CROSS REFERENCE TO RELATED APPLICATION

[1] This application claims the benefit of U.S. Provisional Application 61/425,328, entitled "Light emitting device comprising a removable and replaceable lightgiude," filed December 21, 2010, the entire contents of which is incorporated herein by reference.

TECHNICAL FIELD

[2] The subject matter disclosed herein generally relates to light emitting devices such as luminous signs, light fixuires, backlights, light emitting signs, packaging, light emitting packaging, point-of-piuchase displays, passive displays, and active displays and their components and methods of manufacuue.

BACKGROUND

[3] Traditionally, in order to reduce the thickness of displays edge-lit configurations using rigid lightguides have been used to receive light from the edge and direct light out of a larger area face. These types of light emitting devices are typically housed in relatively thick. rigid frames that do not allow for component or device flexibility and require long lead times for design changes. The volume of these devices rernaiiis large and often includes thick or large frames or bezels around the device. The thick lightguides (typically 2 mm and larger) limit the design configurations, production methods, and illumination modes.

[4] The ability to further reduce the thickness and overall volume of these area light emitting devices has been limited by the ability to couple sufficient light flux into a thinner lightgiude. Typical LED light sources have a light emitting area dimension of at least 1 mm, and there is often difficulty controlling the light entering, propagating through, and coupled out of the 2 mm lightguide to meet design requirements. The displays incorporating the 2 mm lightguides are typically limited to small displays such as those with a 33 cm diagonal or less. Many system sizes are thick due to designs that use large light sources and large input coupling optics or methods. Some systems using one lightguide per pixel (such as fiber optic based systems) require a large volume and have low alignment tolerances. In production, thin lightguides have been limited to coatings on rigid wafers for integrated optical components. SUMMARY

[5] In one embodiment, a packaging for a product comprises a film-based Hghtguide including a light input surface disposed to receive light propagating orthogonal to the light input surface, and a light emitting region defined by the film-based Hghtguide including at least one light extraction feature. Light received by the light input surface propagates through the film-based Hghtguide by total internal reflection and exits the film-based Hghtguide in the light emitting region.

[6] In another embodiment, a packaging for a product includes a Hghtguide defining a Hghtguide region, and including an array of coupling lightguides continuous with the Hghtguide region. Each coupling Hghtguide of the array of coupHng lightguides terminates in an edge and each coupling Hghtguide is folded such that the edges of the array of coupling lightguides form a stack defining a light input surface. A light emitting region is defined within the Hghtguide region by at least one light extraction feature. Light received by the light input siuface propagates through tlie Hghtguide region by total internal reflection and exits the hghtguide region in the light emitting region.

[7] In another embodiment, a method of manufacturing a packaging for a product includes forming a pluraHty of coupling lightguides in a film continuous with a Hghtguide region of the film, arranging at least one light exdaction feature within a light emitting region defined by the hghtguide region, and folding at least one coupling Hghtguide of tlie plurality of coupling lightguides such that ends of the plurality of coupling lightguides form a stack defining a light input surface such that Ught received by the light input surface propagates through the Hghtguide region by total internal reflection and exits tlie Hghtguide region in tlie light emitting region.

BRIEF DESCRIPTION OF THE DRAWINGS

[8] FIG 1 is a top view of one embodiment of a Hght emitting device comprising a light input coupler disposed on one side of a Hghtguide.

[9] FIG 2 is a perspective view of one embodiment of a light input coupler with coupling lightguides folded in tlie -y direction.

[10] FIG 3 is a perspective view of one embodiment of a light emitting point of piu chase (POP) display comprising printed indicia on a surface layer of the POP display and luminous indicia emitting light from the Hghtgiude that is visible through tlie surface layer of the POP display. [11] FIG 4 is a perspective view!of one embodiment of a point of purchase display comprising printed indicia on a surface layer and light emitting indicia emitting light from the first lightguide that is visible through the surface layer and a second input coupler comprising a light source and a second lightguide comprising a fust light emitting region and a second light emitting region disposed to emit light through apertures in the POP display toward the interior region of the POP display.

[12] FIG 5 is a perspective view of the point of purchase display of FIG 4 further comprising products.

[13] FIG 6 is a perspective view of the point of purchase display comprising products of FIG 5 illustrating the path of light through the POP display and products.

[14] FIG 7 is a perspective view of the product of FIG 5 comprising printed indicia on the outer surface of the packaging and a stacked anay of coupling liglitguides with the light input surface comprising input edges of the coupling lightguides disposed to receive light and transmit light into the lightguide on the inner side of the packaging of the product where it is emitted due to the light extraction features in light emitting indicia region of the lightguide through the packaging.

[15] FIG 8 is a perspective view of one embodiment of a product disposed to receive light from a light emitting device with a component in the -y direction and uansinit the light through a lightguide in die -x direction.

[16] FIG 9 is a perspective view of one embodiment of a first product and a second product stacked upon each other disposed to receive light from a light emitting device.

[17] FIG 10 is a cross-sectional side view of one embodiment of a light emitting device comprising a light input coupler and a lightguide with a reflective optical element disposed adjacent a surface.

[18] FIG 11 illustrates an exemplary method of manufacturing a packaging.

DETAILED DESCRIPTION

[19] The features and other details of several embodiments will now be more particulaily described. It will be understood that particular embodiments described herein are shown by way of illustration and not as limitations. The principal features can be employed in vaiious embodiments without departing from the scope of any particular embodiment. All parts and percentages are by weight unless otherwise specified. DEFINITIONS

[20] "Optically coupled" as defined herein refers to coupling of two or more regions or layers such that the luminance of liglit passing from one region to another region is not substantially reduced by Fresnel interfacial reflection losses due to differences in refractive indices between the regions. "Optical coupling" methods include methods of coupling wherein two regions coupled together have similar refractive indices or using an optical adhesive with a refractive index substantially near or between the refractive index of the regions or layers. Examples of "optical coupling" include, without limitation, lamination using an index-matched optical adhesive, coating a region or layer onto another region or layer, or hot lamination using applied pressure to join two or more layers or regions that have substantially close refractive indices. Thermal transferring is another mediod that can be used to optically couple two regions of material. Forming, altering, pruning, or applying a material on the surface of another material are other examples of optically coupling two materials. "Optically coupled" also includes forming, adding, or removing regions, features, or materials of a first refractive index within a volume of a material of a second refractive index such that light travels from the first material to die second material. For example, a white light scattering ink (such as titanium dioxide in a methacrylate, vinyl, or polyurethane based binder) may be optically coupled to a surface of a polycarbonate or silicone film by inkjet printing the ink onto the surface. Similarly, a light scattering material such as titanium dioxide in a solvent applied to a surface may allow the light scattering material to penetrate or adhere in close physical contact with the surface of a polycarbonate or silicone film such that it is optically coupled to the film surface or volume.

[21] "Lightguide" or "waveguide" refers to a region bounded by the condition that liglit rays propagating at an angle that is larger than the critical angle will reflect and remain within the region. In a lightguide, the liglit will reflect or TIR (totally internally reflect) if the angle (a) satisfies the condition:

where iii is the refractive index of the medium inside the lightguide and n ₂ is the refractive index of the medium outside the lightguide. Typically, n ₂ is air with a refractive index of n~l : however, high and low refractive index materials can be used to achieve lightguide regions. The lightguide may comprise reflective components such as reflective films, aluininized coatings, surface relief featuies, and other components that can re-direct or reflect light. The lightguide may also contain non-scattering regions such as substrates. Light can be incident on a lightguide region from the sides or below and surface relief features or light scattering domains, phases or elements within the region can direct light into larger angles such that the light totally internally reflects or into smaller angles such that the light escapes the lightguide. The lightguide does not need to be optically coupled to all of its components to be considered as a lightguide. Light may enter from any face (or interfacial refractive index boundary) of the waveguide region and may totally internally reflect from the same or another refractive index interfacial boundary. A region can be functional as a waveguide or lightguide for purposes illustrated herein as long as the thickness is larger than the wavelength of light of interest. For example, a lightguide may be a 5 micron region or layer of a film or it may be a 3 millimeter sheet comprising a light transmitting polymer.

[22] "In contact" and "disposed on" are used generally to describe that two items are adjacent one another such that the whole item can function as desired. This may mean that additional materials can be present between the adjacent items, as long as the item can function as desired.

[23] A "film" as used herein refers to a thin extended region, membrane, or layer of material.

[24] A "bend" as used herein refers to a deformation or aansformation in shape by the movement of a first region of an element relative to a second region, for example. Examples of bends include the bending of a clothes rod when heavy clothes are hung on the rod or rolling up a paper document to fit it into a cylindrical mailing mbe. A "fold" as used herein is a type of bend and refers to the bend or lay of one region of an element onto a second region such that the fust region covers at least a portion of the second region. An example of a fold includes bending a letter and forming creases to place it in an envelope. A fold does not require that all regions of the element overlap. A bend or fold may be a change in the direction along a first direction along a surface of the object. A fold or bend may or may not have creases and the bend or fold may occur in one or more directions or planes such as 90 degrees or 45 degrees. A bend or fold may be lateral, vertical, torsional, or a combination thereof.

LIGHT EMITTING DEVICE

[25] In one embodiment, a light emitting device comprises a first light source, a light input coupler, a light mixing region, and a lightguide comprising a light enutting region with a liglit extraction feature. In one embodiment, the first light source has a fust liglit source emirting surface, the liglit input coupler comprises an input surface disposed to receive light from the fust light source and transmit- the light through the light input coupler by total internal reflection through a plurality of coupling lightguides. In this embodiment, light exiting the coupling lightguides is re-combined and mixed in a light mixing region and directed dirough total internal reflection within a lightguide or lightguide region. Within the lightguide, a portion of incident light is directed within the light extracting region by light extracting feanires into a condition whereupon the angle of light is less than the critical angle for the lightguide and the directed light exits the lightguide through the liglitguide light emitting surface.

[26] In a further embodiment, the liglitguide is a film with light extracting features below a light eniitting device output surface within the film and film is separated into coupling lightguide ships which are folded such that they form a light input coupler with a first input surface formed by the collection of edges of the coupling lightguides. LIGHT INPUT COUPLER

[27] In one embodiment, a light input coupler comprises a plurality of coupling lightguides disposed to receive light emitting from one or more light sources and channel the light into a lightguide. In one embodiment, the plurality of coupling lightguides are ships cut from a lightguide film such that they remain un-cut on at least one edge but can be rotated or positioned (or translated) substantially independently from the lightguide to couple liglit through at least one edge or surface of 'the strip. In another embodiment, the plurality of coupling lightguides are not cut from the lightguide film and are separately optically coupled to the light source and the lightguide. hi one embodiment, the light input coupler comprises at least one light source optically coupled to the coupling lightguides which join together in a light mixing region. In another embodiment, the light input coupler is a collection of strip sections cut from a region film which are arranged in a grouping such that light may enter through the edge of a grouping or arrangement of strips. In another embodiment, the light emitting device comprises a light input coupler comprising a core region of a core material and a cladding region or cladding layer of a cladding material on at least one face or edge of the core material with a refractive index less than the core material. In another embodiment, the liglit input coupler compiises a plurality of coupling lightguides wherein a portion of liglit from a light source incident on the face of at least one strip is directed into the lightguide such that the portion of light propagates in a waveguide condition. The light input coupler may also comprise one or more of the following: a snip folding device, a strip holding element, and an input surface optical element.

LIGHT SOURCE

[28] In one embodiment, a light emitting device comprises one or more of the following light sources: fluorescent lamp, cylindrical cold-cathode fluorescent lamp, flat fluorescent lamp, light emitting diode, organic light emitting diode, field emissive lamp, gas discharge lamp, neon lamp, filament lamp, incandescent lamp, electroluminescent lamp, radiofhiorescent lamp, halogen lamp, incandescent lamp, mercury vapor lamp, sodium vapor lamp, high pressure sodium lamp, metal halide lamp, tungsten lamp, carbon arc lamp, electiOluminescent lamp, laser, photonic bandgap based light source, quantum dot based light source, high efficiency plasma light sotirce, microplasma lamp. The light emitting device may comprise a plurality of liglit sources arranged in an anay, on opposite sides of lightguide, on orthogonal sides of a lightguide, on 3 or more sides of a lightguide, or on 4 sides of a substantially planer lightguide. The array of light sources may be a linear array with discrete LED packages comprising at least one LED die. In another embodiment, a liglit emitting device comprises a plurality of light sources within one package disposed to emit light toward a liglit input surface. In one embodiment, the light emitting device comprises any suitable number of liglit sources, such as 1 , 2. 3, 4, 5, 6, 8, 9, 10, or more than 10 light sources. In another embodiment, the light emitting device comprises an organic light emitting diode disposed to emit liglit as a light emitting film or sheet. In another embodiment, the light emitting device comprises an organic light emitting diode disposed to emit light into a lightguide.

[29] In one embodiment, a light emitting device comprises at least one broadband light source that emits light in a wavelength specnnni larger than 100 nanometers. In another embodiment, a light emitting device comprises at least one narrowband light source that emits light in a narrow bandwidth less than 100 nanometers. In another embodiment, a light emitting device comprises at least one broadband light source that emits light in a wavelength spectrum larger than 100 nanometers or at least one narrowband light source that emits liglit in a narrow bandwidth less than 100 nanometers. In one embodiment a light emitting device comprises at least one nanowband light somce with a peak wavelength within a range selected from the group: 300nm-350um, 350nin-400nm, 400nm-450nm, 4 ^' 50um-500nin, 5OOnni-550nm, 550nni-600run, 600nn*-650nm, 650nm-700ntn, 700nm-750nm. 750nni- 800nin, and 800nni-1200nrn. In one embodiment, at least one ligh source is a white LED package comprising a red LED. green LED, and blue LED. In another embodiment a light enntring device comprises a light source emitting light in an angular full-width at half maximum inteusity of less than one selected from 150 degrees, 120 degrees. 100 degrees, 80 degrees, 70 degrees, 60 degrees, 50 degrees, 40 degrees, 30 degrees. 20 degrees, and 10 degrees.

DYNAMIC LIGHT EMITTING EFFECTS

[30] In one embodiment, the light emitting device comprises a light source and a controller wherein the light is turned off and on in a flashing manner. The delay between the on to off transition and the delay between the off to on transition may be constant, variable, or equal to each other. For example, in one embodiment, a liglit emitting sign comprises a lightguide with light emitting indicia in the form of "OPEN" that flashes off for 1 second and then back on for 10 seconds before repeating the cycle. In another embodiment, the liglit emitting device comprises a fust light source and a second light source wherein by sequentially turning on the first light source and then the second light source, a dynamic sign effect is achieved, hi another embodiment, the light output of one or more light sources is slowly decreased or increased such that a gradual fade-off or fade-on effect is achieved.

[31] The light sources may be disposed in the same or different light input couplers or lightguides. For example, in one embodiment, the light emitting device comprises a red LED light source disposed to couple light into a first set of coupling lightguides and a blue LED liglit source disposed to couple light into a second set of coupling lightguides. By switching the lights on and off in an alternating fashion, a dynamic sign effect can be achieved (to attract attention for example). In another example, in one embodiment, a liglit emitting device comprises thiee lightguides and tliree light input couplers disposed to receive liglit from three white light sources. The light extraction feauires on the three different lightguides foim diree different images suggesting movement of the images, hi this embodiment, by cycling through the thiee white LEDs, the images will sequentially illuminate and suggest motion. In another embodiment, the relative output of two or more light sources in a light emitting device are adjusted such that the color, luminance, or both are changed in one or more light emitting regions. For example, in one embodiment, the liglit emitting device comprises a red LED. green LED, and blue LED disposed to couple light into a stack of coupling lightguides such that the light propagates through the coupling lightguides, mixes within the coxipling lightguides, mixes within a light mixing region and lightguide region and is output in a light emitting region in the form of indicia. By changing the relative output of LEDs, the color of the light emitting indicia will change and can be used to draw attention or provide instructive or other dynamic effects.

[32] In another embodiment, a light emitting device comprises a first lightguide and second lightguide disposed to receive light from a first and second light source, respectively, through two different optical paths wherein die first and second light source are different colors and the light emitting regions of the first and second lightguides comprise an overlap region wherein combined light emitted from both regions exits the light emitting device from the same light emitting overlap region in a color different than the color of the first or second light sources. For example, in one embodiment, a light emitting device comprises a first lightguide with a white light LED disposed to couple light through coupling lightguides into the first lightguide such that light is emitted from die lightguide displaying the indicia "SALE". In a particular embodiment, the light emitting device further comprises a blue LED disposed to couple light into a different set of coupling lightguides and into a second lightguide laminated to the first lightguide with an overlapping and aligned light emitting region also displaying the indicia "SALE", hi this embodiment, by increasing the blue LED light output, the color of the indicia "SALE" may transition from white to bluish white or pale blue color. Also, for example, in this embodiment, the output of die blue light source may be increased to compensate for blue light absorption and/or scattering from the core lightguide material.

[33] hi another embodiment, for example, two differently shaped light emitting regions on two lightguides disposed to receive light from two different colored light soiuces emit light in different colors such that die combination or separate regions have different visible colore, hi another embodiment, the light emitting device compiises two or more lightguides disposed to receive light from two or more light sources and the lightguides are sequentially illuminated by the light sources such that a dynamic effect is achieved. For example, a first, second, and third lightguide comprise light extraction regions spatially separated and the lightguides are sequentially Uhiniinated with light from three white LEDs and the display appears to show snow moving down the display. In anotlier embodiment, a light emitting device comprises a first lightguide and second lightguide disposed to receive light from a fust and second light source through two different optical paths, respectively. wherein the first and second light source are diffeieut colors and the light emitting regions of the first and second lightguides comprise an overlap region wherein light emitted from both regions exits the light emitting device from the same light emitting overlap region, and when the first and second light sources are emitting light, the light emitting device emits light in the overlap region of a color different than the color of the first or second light sour ces and emits light in a non-overlap region of the first color. For example, in one embodiment, one lightguide comprises a large red square light emitting region illuminated by a red LED and a second lightguide comprises a blue light emitting region in the form of the text "SALE" centered in a region above the red light emitting square region such that when the blue LED is turned on a purple "SALE" indicia is seen centered within the red square.

LIGHT INPUT COUPLER INPUT SURFACE

[34] In one embodiment, a film-based lightguide comprises an array of coupling lightguides and the film comprises bounding edges along its periphery. In one embodiment, the light input coupler comprises a collection of coupling lightguides with a plurality of bounding edges forming a light coupler input surface. In one embodiment, the light input coupler comprises a collection of coupling lightguides with a plurality of edges forming a light coupler input surface. The coupling lightguides may be grouped together such the edges opposite the lightguide region are brouglit together to form an input surface comprising of their thin edges, hi another embodiment, a substantially planar light ttansmitting element is optically coupled to the grouped edges of coupling lightguides. The light input coupler or an element or region therein may also comprise a cladding material or region.

[35] The light input coupler may also comprise a guide that comprises a mechanical, electrical, manual, guided, or other system or component to facilitate the alignment of the light source in relation to the light input surface. The guide device may define an opening or window and may physically or optically couple together one or more of the following: a light source (or component physically attached to a light source), a light input coupler, a coupling lightguide, a housing, and an electrical, thermal, or mechanical element of the light emitting device.

LIGHT TURNING AND LIGHT COLLI ATING OPTICAL ELEMENT

[36] In another embodiment, a light mining optical element turns the optical axis of the light from the light source in a first plane within the light tiuning element and colliinates the light in the first plane, in a second plane orthogonal to the first plane, or a combination thereof, hi another embodiment, the light uuning optical element comprises a light mining region and a collimating region. For example, in one embodiment, the light turning optical element is a 1 millimeter (mm) duck lens with a curved profile in one plane cut from a 1 mm sheet of PMMA using a carbon dioxide (C0 ₂ ) laser cutter.

LIGHT BLOCKING ELEMENT

[37] In one embodiment, the light input coupler comprises a light blocking element to block external light from reaching the lightguide or lightguide region or to block light emitted from a region of the light emitting device from escaping the device being seen by a viewer. In one embodiment, the light blocking element prevents a significant portion of incident light from escaping or entering the light input coupler through absorption, reflection, or a combination thereof.

COUPLING LIGHTGUIDES

[38] hi one embodiment, the coupling lightguide is a region wherein light within the region can propagate in a waveguide condition and a portion of the light input into a surface or region of the coupling lightguides passes through the coupling lightguide toward a lightguide or light mixing region. In one embodiment, coupling lightguides are defined by "leg" regions extending from a "body" (lightguide region) of a film, hi one embodiment, the light propagating in a waveguide condition within the coupling lightguide reflects from the outer surfaces of the coupling lightguide, thus totally internally reflecting within the volume of the coupling lightgtude. hi another embodiment, the coupling lightguide comprises a cladding region or other region optically coupled to a core region of the coupling lightguide. In this embodiment, a portion of the light within the coupling lightguide may propagate through the core region, a portion of the light within the coupling lightguide may propagate through the cladding region or other region, or light may propagate through both regions in a waveguide condition (or hi a non-waveguide condition near the input surface, near a light extracting layer on the cladding or other area, or near the bend region). The coupling lightguide, in some embodiments, may serve to geometrically transform a portion of the flux from a light source from a first shaped area to a second shaped area different from the first. In an example of this embodiment, the light input surface of the light input coupler formed from the edges of folded ships (coupling liglitguides) of a planar film has dimensions of a rectangle that is 3 millimeters by 2.7 millimeters and the light input coupler couples light into a planar section of a film in the Ught mixing region with cross-sectional dimensions of 40.5 millimeters by 0.2 millimeters. In one embodiment, the coupling lightguides provide light channels whereby light flux entering the coupling lightguides in a fust cross-sectional area can be redistributed into a second cross-sectional area different from the first cross-sectional area at the light output region of the liglit input coupler. The light exiting the liglit input coupler or light mixing region may then propagate to a lightguide or lightguide region which may be a separate region of the same element (such as a separate region of the same film). In one embodiment, one or more of the following: light source, light collimating optical element, liglit source primary optic, light source secondary optic, Ught input surface, optical element disposed between the light source and one or more of the following: coupling lightguide, shape of the coupling lightguide, shape of the mixing region, shape of the light input coupler, and shape of an element or region of the light input coupler provides light within the coupling lightguide with an angular full-width of half maximum intensity chosen from the group of less than 80 degrees, less than 70 degrees, less than 60 degrees, less than 50 degrees, less than 40 degrees, less than 30 degrees, less than 20 degrees, less than 10 degrees, between 10 degrees and 30 degrees, between 30 degrees and 50 degrees, between 10 degrees and 60 degrees and between 30 degrees and 80 degrees.

LIGHT MIXING REGION

[39] In one embodiment, a light emitting device comprises a light mixing region disposed in an optical path between the light input coupler and the lightguide region. The light mixing region can provide a region for the light output from individual coupling lightguides to mix together and improve at least one of the spatial luminance imifonnity, spatial color luuformity, angular color uniformity, angular luminance uniformity, angular luminous intensity uniformity or any combination thereof within a region of the lightguide or of the surface or output of the light emitting region or light einirting device.

LIGHT OUTPUT OPTICAL ELEMENT

[40] In one embodiment, a light emitting device comprises a light output optical element disposed to receive liglit from a light source and couple the liglit into a film-based lightguide. In one embodiment, the light output optical element is a light transmitting optical element that receives liglit from a liglit source and transmits liglit from the liglit soiuce through a light transmitting region such that when optically coupled to a film-based lightguide, a portion of the light will propagate into the lightguide through a light receiving region and propagate under total internal reflection.

CLADDING LAYER

[41] In one embodiment, at least one of the light input coupler, coupling lightguide, light mixing region, lightguide region, and lightguide comprises a cladding layer optically coupled to at least one surface. A cladding region, as used herein, is a layer optically coupled to a surface wherein the cladding layer comprises a material with a refractive index, n _cbd , less than the refractive index of the material, rim, of the surface to which it is optically coupled. In one embodiment, n _m -n _< :i_d is one selected from the group: 0.001-0.005, 0.001-0.01, 0.001-0.1 , 0.001-0.2, 0.001-0.3, 0.001-0.4, 0.01-0.1, 0.1-0.5, 0.1-0.3, 0.2-0.5, greater- than 0.01 , greater than 0.1, greater than 0.2, and greater than 0.3. In one embodiment, the cladding includes one or more of the following: methyl based silicone pressure sensitive adhesive, fluoropolymer material (applied with using coating comprising a fluoropolymer substantially dissolved in a solvent), and a fluoropolymer film. In another embodiment, the cladding is removed or absent in the region disposed between the lightguide regions of two coupling lightguides disposed to receive light from a light source or near a light input surface. By removing or not applying or disposing a cladding in the region between the input ends of two or more coupling lightguides disposed to receive light from a light source, light is not directly coupled into the cladding region edge.

CLADDING LAYER MATERIALS

[42] In one embodiment, fluoropolymer materials may be used as a low refractive index cladding material and may be broadly categorized into one of two basic classes: amorphous fluoropolymers comprising interpolymerized units derived from vinylidene fluoride (VDF) and hexafluoropropylene (HFP) and optionally tetrafluoroethylene (TFE) monomers, and homo and copolymers based on fluorinated monomers such as TFE or VDF which do contain a crystalline melting point such as polyvinylideue fluoride (PVDF).

[43] In one embodiment, the cladding material is a nano-structured material comprising fibers, particles, or domains widi an average diameter or dimension in the plane parallel to the core layer surface or perpendicular to the core layer surface less than one selected from the group: 1000, 500, 300, 200, 100, 50, 20, 10, 5, and 2 nanometers. For example, in one embodiment, the cladding layer is a coating comprising nauostructured fibers including polymeric materials such as, without limitation, cellulose, polyester. PVC, PTFE. polystyrene. PMMA. PDMS. or other light transmittin or partially light transmitting materials.

REFLECTIVE ELEMENTS

[44] In one embodiment, one or more of the following: light source, light input siuface, light input coupler, coupling lightguide, lightguide region, and lightguide comprises a reflective element or siuface optically coupled to it, disposed adjacent to it, or disposed to receive light from it wherein the reflective region is one selected from the group: specularly reflecting region, diffusely reflecting region, metallic coating on a region (such as an ΓΓΟ coating, Alumiuized PET, Silver coating, etc.), multi-layer reflector dichroic reflector, multilayer polymeric reflector, giant birefringent optical films, enhanced specular reflector films, reflective ink or particles within a coating or layer, and a white reflective film comprising one or more of the following: titanium dioxide, barium sulfate, and voids.

HOUSING OR HOLDING DEVICE FOR LIGHT INPUT COUPLER

[45] hi one embodiment, a light emitting device comprises a housing or holding device that holds or contains at least part of a light input coupler and hght source. The housing or holding device may house or coutain within one or more of the following: light input coupler, light source, coupling lightguides, lightguide, optical components, electtical components, heat sink or other thermal components, attachment mechanisms, registration mechanisms, folding mechanisms devices, and frames. The housing or holding device may comprise a plurality of components or any combination of the aforementioned components. The housing or holding device may serve one or more of fiinctions including, without limitation, the following: protection fiOm dust and debris contamination, provide air-tight seal, provide a water-tight seal, house or contain components, provide a safety housing for electrical or optical components, assist with the folding or bending of the coupling lightguides, assist in the alignment or holding of the lightguide, coupling lightguide, hght source or light input coupler relative to another component, maintain the arrangement of the coupling lightguides, recycle light (such as with reflecting inner walls), provide attachment mechanisms for attaching the light emitting device to an external object or surface, provide an opaque container such that stray light does not escape through specific regions, provide a translucent surface for displaying indicia or providing illumination to an object external to the light emitting device, comprise a connector for release and interchangeability of components, and provide a latch or connector to connect with other holding devices or housings.

CURVED OR FLEXIBLE HOUSING

[46] In a particular embodiment, the housing comprises at least one curved surface. A curved surface can permit non-linear shapes or devices or facilitate incorporating non-planer or bent lightguides or coupling lightguides. In one embodiment, a light emitting device comprises a housing with at least one curved surface wherein the housing comprises curved or bent coupling lightguides. In another embodiment, the housing is flexible such that it may be bent temporarily, permanently or serni-permanently.

REMOVABLE AND REPLACEABLE COMPONENT OF LIGHT EMITTING DEVICE

[47] In one embodiment, the light emitting device comprises one or more removable and replaceable sections, regions, components, or collection of components. By removing less than all of the components of the light emitting device, a portion of the light emitting device may remain installed or usable. For example, in one embodiment, the light source may be removed and a new one may be installed as an upgrade or replacement. Similarly, in another example, the lightguide and coupling lightguides may be removed to display a new logo or indicia without requiring replacement of the hght input coupler. Other examples include, but are not limited to, replacing the light input coupler, the light extraction region, the lightguide comprising the light extraction region, the lightguide comprising coupling lightguides, a cartridge, a total internal reflection component comprising a cladding region or a low contact area cover, electrical components, a power cord, an LED driver, a light input optical element, a security component, a memory chip, a light emitting region, etc.

LOW CONTACT AREA COVER

[48] In one embodiment, a low contact area cover is disposed between at least one coupling lightguide and the exterior to the light emitting device. The low contact area cover or wrap provides a low smface area of contact with a region of the hghtguide or a coupling lightguide and may further provide at least one selected from the group: protection froin fingerprints, protection from dust or air contaminants, protection froin moisture, protection from internal or external objects that would decouple or absorb more light than the low contact area cover when in contact in one or more regions with one or more coupling liglitguides, provide a means for holding or containing at least one coupling lightguide, hold the relative position of one or more coupling lightguides. and prevent the coupling liglitguides from unfolding into a larger volume or contact with a surface that could de-couple or absorb light. In one embodiment, the low contact area cover is disposed substantially around one or more coupling lightguide stacks or arrays and provides one or more of the functions selected from the group: reducing the dust buildup on the coupling hghtguides. protecting one or more coupling liglitguides from frustrated total internal reflection or absorption by contact with another light transmitting or absorbing material, and preventing or limiting scratches, cuts, dents, or deformities from physical contact with other components or assemblers and/or users of the device.

[49] In another embodiment, the low contact area cover comprises a material with an effective refractive index less than the core layer due to microstructures and/or nanostructiues. For example, in one embodiment, the low contact area cover is a coating or material comprising nanostrucmred fibers, comprising polymeric materials such as. without limitation, cellulose, polyester, PVC, PTFE, polystyrene, PMMA, PDMS, or other light transmitting or partially light transmirting materials. In one embodiment, the low contact area is a paper or similar sheet or film (such as a filter paper) comprising fibrous, micro- stmctured, or nano-strucnired materials or surfaces. In one embodiment, the low contact area material is a woven material. In another embodiment, the low contact area material is non- woven material.

LIGHTGUIDE CONFIGURATION AND PROPERTIES

[50] The use of plastic film with thickness less than 0.5mm for edge lit hghtguides can hold many advantages over using plastic plate or sheets. A flexible film may be able to be shaped to surfaces, be folded up for storage, change shape as needed, or wave in the air. Another advantage may be lower cost. The reduction in dnckuess helps reduce the cost for material, fabrication, storage and shipping for a lightguide of a given width and length. Another reason may be that the decreased thickness makes it able to be added to surfaces without appreciable change in the surface's shape, thickness and or appearance. For example, it can be added to the siuface of a window easily without changing the look of the window. Another advantage may be that the film or lightguide can be rolled up. This helps in transportability, can hold some functionality, and may be particularly useful for hand-held devices where a roll-out screen is used. A fifth reason is that the film can weigh less, which again makes it easier to handle and transport, A sixth reason may be that film is commonly exnuded in large rolls so larger edge-lit signage can be produced. Finally, a seventh reason may be that there are many companies set up to coat, cut, laminate and manipulate film since film is useful for many other industries. Plastic films are made by blown or cast-extrusion in widths up to 6.096 metei's or longer and in rolls thousands of metei's long. Co-extrusion of different materials from two to 100 layers can be achieved with special extrusion dies.

THICKNESS OF THE FILM OR LIGHTGUIDE

[51] In one embodiment, the thickness of the film, lightguide or lightguide region is within a range of 0.005mm to 0.5mni. In another embodiment, the thickness of the film or lightguide is within a range of 0.025 millimeters to 0.5 millimeters. In a fiirther embodiment, the thickness of the film, lightguide or lightguide region is within a range of 0.050 millimeters to 0.175 millimeters. In one embodiment, the thickness of the film, lightguide or lightguide region is less than 0.2 millimeters or less than 0.5 millimeters. In one embodiment, the average thickness of the lightguide or core region is less than one selected from the group: 150 microns, 100 microns. 60 microns, 30 microns, 20 microns, 10 microns, 6 microns, and 4 microns. In one embodiment, at least one selected from the group: thickness, largest thickness, average thickness, greater than 90% of the entire thickness of the film, lightguide, and a lightguide region is less than 0.2 millimeters.

REFRACTIVE INDEX OF THE LIGHT TRANSMITTING MATERIAL

[52] In one embodiment, the core material of the lightguide has a high refractive index and the cladding material has a low refiactive index. In one embodiment, the core is formed from a material with a refractive index (n _D ) greater than one selected from the group: 1.3. 1.4, 1.5, 1.6, 1.7, 1.8. 1.9. 2.0, 2.1 , 2.2, 2.3, 2.4, 2.5, 2.6. 2.7, 2.8 _; 2.9, and 3.0. In another embodiment, the refractive index (n _D ) of the cladding material is less than one selected from the group: 1.1. 1.2, 1.3, 1.4. 1.5. 1.6, 1.7. 1.8, 1.9. 2.0. 2.1. 2.2. 2.3, 2.4, and 2.5.

SHAPE OF THE LIGHTGUIDE

[53] In one embodiment, at least a portion of the lightguide shape or lightguide surface is at least one selected from the group: substantially planar, curved, cylindrical, a formed shape from a substantially planar film spherical, partially spherical, angled, twisted, rounded, have a quadric surface, spheroid, cuboid, parallelepiped, triangular prism. rectangular prism, ellipsoid, ovoid, cone pyramid, tapered triangular prism, wave-like shape, and other known geometrical solids or shapes.

LIGHTGUIDE MATERIAL

[54] hi one embodiment, a light emitting device comprises a lightguide or lightguide region formed from at least one light transmitting material. In one embodiment, the lightguide is a film comprising at least one core region and at least one cladding region, each comprising at least one light transmitting material, hi one embodiment, the core material is substantially flexible (such as a rubber or adhesive) and the claddmg material supports and provides at least one selected from the group: increased fiexiual modulus, increased impact strength, increased tear resistance, and increased scratch resistance for die combined element. In another embodiment, the cladding material is substantially flexible (such as a rubber or adhesive) and the core material supports and provides at least one selected from the group: increased flexural modulus, increased impact strength, increased tear resistance, and increased scratch resistance for the combined element. The ^' light, transmitting material used within an embodiment may be a thermoplastic, thennoset, rubber, polymer, high transmission silicone, glass, composite, alloy, blend, silicone, other light transmitting material, or a combination thereof, hi one embodiment, a component or region of the light emitting device comprises a light transmitting material selected from the group: cellulose derivatives (e.g., cellulose ethers such as ethylcellulose and cyanoethylcellulose, cellulose esters such as cellulose acetate), acrylic resins, styrenic resins (e.g., polystyrene), polyvinyl-series resms [e.g., poly(vinyl ester) such as poly(vinyl acetate), poly(vinyl halide) such as poly(vinyl chloride), polyvinyl alkyl ethers or polyether-series resins such as poly(vinyl methyl ether), polyvinyl isobutyl ether) and poly(vinyl t-butyl ether)], polycarbonate-series resins (e.g., aromatic polycarbonates such as bispheuol A-type polycarbonate), polyester-series resins(e.g.. homopolyesters. for example, polyalkylene terephtlialates such as polyethylene terephthalate and polybutylene terephthalate, polyalkylene naphthalates corresponding to the polyalkylene terephtlialates: copolyesters containing an alkylene terephthalate and/or alkylene naphthalate as a main component; honiopolymers of lactones such as polycaprolactone), polyamide-series resin (e.g., nylon 6. nylon 66, nylon 610), uretliane- series resins (e.g., thermoplastic polyurethane resins), copolymers of monomers forming the above resins [e.g., styrenic copolymers such as methyl methacrylate-styrene copolymer (MS resin), aciylouitrile-styrene copolymer (AS resin). styrene-(meth)acrylic acid copolymer. styrene-maleic anhydride copolymer and styrene-butadiene copolymer, vinyl acetate-vinyl chloride copolymer, vinyl alkyl ether-maleic anliydride copolymer], Incidentally, the copolymer may be whichever of a random copolymer, a block copolymer, or a graft copolymer. MULTILAYER LIGHTGUIDE

[55] In one embodiment, the lightguide comprises at least two layers or coatings. In another embodiment, die layers or coatings function as at least one selected froui the group: a core layer, a cladding layer, a tie layer (to promote adhesion between two other layers), a layer to increase flexural strength, a layer to increase the impact strength (such as Izod, Charpy. Gardner, for example), and a carrier layer. In a further embodiment, at least one layer or coating comprises a inicrostructure, surface relief pattern, light extraction features, lenses, or other non-flat surface feamres which redirect a portion of incident light from within the lightguide to an angle whereupon it escapes the lightguide in the region near- the feahire. For example, the carrier film may be a silicone film with embossed light extraction features disposed to receive a thennoset polycarbonate resin. In another embodiment, the carrier' film is removed from contact with the core material in at least one region. For example, the carrier film may be an embossed FEP film and a thennoset methacrylate based resin is coated upon the film and cured by heat, light, other radiation, or a combination thereof. In another embodiment, the core material comprises a rnediacrylate material and the cladding comprises a silicone mateiial. In anotlier emboduneut, a cladding material is coated onto a carrier film and subsequently, a core layer material, such as a silicone, a PC, or a PMMA based material, is coated or extruded onto the cladding material. In one embodiment, the cladding layer is too thin to support itself in a coating line and therefore a carrier film is used. The coating may have surface relief properties one the side opposite the carrier film, for example. LIGHT EXTRACTION METHOD

[56] In one embodiment, at least one selected from the group: the lightguide, the lightguide region, and the hght emitting region comprises at least one light exnaction feature or region. In one embodiment, the light extraction method includes operatively coupling a light extraction feature to the core region, lightguide region, or to a mateiial operatively coupled to the core region or lightguide region. Operatively coupling the light exnaction feature to a region includes, without limitation: adding, removing, or altering material on the suiface of the region or within the volume of the region; disposing a material on the surface of the region or within the volume of the region; applying a material on the surface of the region or within the volume of the region: printing or painting a material on the surface of the region or within the volume of the region; removing material from the surface of the region or fr om the volume of the region; modifying a surface of the region or region within the volume of the region; stamping or embossing a surface of the region or region within the volume of the region: scratching, sanding, ablating, or scribing a suiface of the region or region within the volume of the region; forming a light extraction feature on the surface of the region or within the volume of the region; bonding a material on the surface of the region or within the volume of the region; adhering a material to the suiface of the cladding region or within the volume of the cladding region; optically coupling the light extraction feature to the surface of the region or volume of the region; optically coupling or physically coupling the light extraction feature to the region by an intermediate surface, layer or material disposed between the light extraction feature and the region. In another embodiment, a light extraction feature is operatively coupled to a region such that a portion of light propagating within the region incident on the light extraction feature will exit the region or be re-directed to an angle smaller than the critical angle such that it does not remain within the region, core region, coupling lightguide, lightguide, or other region through which it is propagating by total internal reflection.

[57] In one embodiment, the light extraction region or feamre is defined by a raised or recessed surface partem or a volumetric region. Raised and recessed surface patterns include, without limitation, scattering material, raised lenses, scattering surfaces, pits, grooves, surface modulations, microlenses, lenses, diffractive surface features, holographic suiface features, photonic bandgap features, wavelength conversion materials, holes, edges of layers (such as regions where the cladding is removed from covering the core layer), pyramid shapes, prism shapes, and other geometrical shapes with flat surfaces, curved surfaces, random surfaces, quasi-random surfaces and combinations thereof. The volumetric scattering regions within the light extraction region may comprise dispersed phase domains, voids, absence of other materials or regions (gaps, holes), air gaps, boimdaiies between layers and regions, and other refractive index discontinuities within the volume of the material different that co-planar layers with parallel inteifacial surfaces. In one embodiment, the light extracting region comprises angled or curved suiface or volumetric light extracting features that redirect a first rediiectiou percentage of light into an angular range within 5 degrees of the nonnal to the light emitting surface of the light emitting device, hi another embodiment, the first redirection percentage is greater than one selected from the group: 5, 10, 20. 30, 40. 50, 60. 70, 80, and 90. In one embodiment, the light extr action features are light redirecting features, light extracting regions or light output coupling features. In a further embodiment, the light extraction feature has an angular FWHM intensity of transmitted light greater than one selected from the group: 10 degrees, 20 degrees, 30 degrees. 40 degrees. 50 degrees, 60 degrees, 70 degrees. 80 degrees, 90 degrees, and 100 degrees when measured with light incident normal to the large area surface of the film at the feature with a 532nm laser diode with a divergence less than 5 milliradians where the size of the cross-sectional area of tire light from the laser is smaller than the light extraction feature.

[58] In one embodiment, the lightguide or lightguide region comprises light extraction features in a plurality of regions. In one embodiment, the lightguide or lightguide region comprises light extraction features on or within at least one selected from the group: one outer surface, two outer surfaces, two outer and opposite surfaces, an outer surface and at least one region disposed between the two outer surfaces, within two different volumetric regions substantially within two different volumetric planes parallel to at least one outer surface or light emitting surface or plane, and within a plurality of volumetric planes. In another embodiment, a light emitting device comprises a light emitting region on the lightguide region of a lightguide comprising more than one region of light extraction featiu es. In another embodiment, one or more light extraction featiues are disposed on top of another light extraction feature. For example, grooved light extraction features could comprise light scattering hollow microspheres which may increase the amount of light extracted from die lightguide or which could fiirther scatter or redirect the light that is extracted by the grooves. More than one type of light extraction feature may be used on the surface, within the volume of a lightguide or lightguide region, or a combination thereof.

[59] In another embodiment, the average dimension of the light extraction features in the light emitting region in a direction peipendicular to the optical axis of the light within the lightguide at the light extraction feature or the direction peipendicular to the surface of the lightguide between die light extracting features is less than one selected from die group: 1mm, 500 microns, 250 microns, 200 microns. 150 microns, 100 microns, 75 microns, 50 microns, 25 microns. 20 microns, 10 microns, 5 microns, 2 microns, 1 microns, 0.5 microns, and 0.3 microns. [60] In one embodiment, die separation distance between a first light extraction feature and the closest neighboring light extraction feature is less than one selected from the group: 200 microns. 150 microns. 100 microns. 75 microns, 50 microns. 25 microns, and 20 microns. In another embodiment, the average separation distance between two neighboring light extraction fea ires in one or more light emitting regions of the film-based lightguide in a direction substantially parallel to the optical axis of the light propagating within the lightguide in the region of the light extracting feanires is less than one selected from the group: 200 microns, 150 microns, 100 microns, 75 microns, 50 microns, 25 microns, and 20 microns.

[61] hi one embodiment, the light extraction feature is substantially directional and comprises one or more selected from the group: angled surface feature, curved surface feature, rough surface feature, random surface feature, asymmetric surface feature, scribed surface feanire, cut surface feature, noh-planar surface feature, stamped surface feanire. molded surface feature, compression molded surface feanire. thermoformed surface feature, milled surface feanire, extruded rnixnire, bleuded materials, alloy of materials, composite of symmetric or asymmetrically shaped materials, laser ablated surface feanire, embossed surface feanire, coated surface feature, injection molded surface feature, extruded surface feature, and one of the aforementioned features disposed in the volume of the lightguide. For example, in one embodiment, the directional light extraction feature is a 100 micron long 45 degree angled facet groove formed by UV cured embossing a coating on the lightguide film that substantially directs a portion of the incident light within the lightguide toward 0 degrees from the surface nonual of the lightguide. The light extraction region, light extraction feanire, or light emitting region may be disposed on the upper and/or lower surface of the lightguide.

[62] In one embodiment, at least one light extraction feanire is an array, pattern or arrangement of a wavelength conversion material selected from the group: a fluorophore. phosphor, a fluorescent dye, an inorganic phosphor, photonic bandgap mateiial. a quantum dot material, a fluorescent protein, a fusion protein, a fluorophores attached to protein to specific functional groups, quantum dot fluorophores, small molecule fluorophores, aromatic fluorophores. conjugated fluorophores, and a fluorescent dye scintillators, phosphors such as Cadmium sulfide, rare-earth doped phosphor, and other known wavelength conveision materials.

[63] In one embodiment, the light extraction feature is a specularly, diffusive, or a combination thereof reflective material. For example, the light extraction feature may be a substantially specularly reflecting ink disposed at an angle (such as coated onto a groove) or it may be a substantially diffusely reflective ink such as an ink comprising titanium dioxide particles within a methacrylate-based binder (white paint).

[64] In another embodiment, the light emitting device comprises a lightguide with a liglit exuaction feature optically coupled to the core region of the lightguide. For example, in one embodiment, the light extraction feature is a white reflective film coupled spatially and optically by a partem of liglit transmitting adhesive regions disposed on the core region of the lightguide. In this embodiment, the air gaps between the adhesive regions totally internally reflect the light incident at the core region-air interface and the adhesive transmits incident light to a white reflection film that redirects light to angles outside the total internal reflection condition.

[65] The pattern or arrangement of liglit extraction features may vary in size, shape, pitch, location, height, width, depth, shape, orientation, in the x, y, or z directions. Patterns and formulas or equations to assist in the determination of the arrangement to achieve spatial luminance or color uniformity are known in the art of edge-illuminated backlights.

VISIBILITY OF LIGHT EXTRACTION FEATURES

[66] In one embodiment, at least one light extraction region comprises liglit extraction features which have a low visibility to the viewer when the region is not illmuinated by light from within the lightguide (such as when the device is in the off-state or the particular lightguide in a multi-lightgiude device is not illuminated). In one embodiment, the liuiiinance at a first measurement angle of at least one selected from the group: lightguide region, square centimeter measurement area of the light enutting surface corresponding to light redirected by at least one light extraction featiue, light emitting region, light extraction feature, and liglit extracting surface feature or collection of light extraction features is less than one selected from the group: 0.5 cd/in ² , 1 cd m ² , 5 cd m ² . 10 cd/ru ² , 50 cd/m ² . and 100 cd/m ² when exposed to diffuse illuminance from an integrating sphere of one selected froin the group: 10 lux. 50 lux. 75 lux, 100 lux, 200 lux. 300 lux. 400 lux. 500 lax, 750 lux, and 1000 lux incident on the surface when place over a black, light absorbing surface. Examples of a light absorbing surface include, witliout limitation, a black velour cloth material, a black anodized aluminum, a material with a diffuse reflectance (specular component included) less than 5%, Light Absorbing Black-Out Material from Edmund Optics Inc., and a window to a light trap box (a box with light absorbing black veloiu- or other material lining the walls). [67] In one embodiment, the individual light extracting surface features, regions, or pixels, are not discernible as an individual pixel when the device is emitting light in an on state and is not readily discernible when the light emitting device is in the off state when viewed at a distance greater than one selected from the group: 10 centimeters. 20 centimeters. 30 centimeters. 40 centimeters, 50 centimeters, 100 centimeters, and 200 centimeters. In this embodiment, the area may appear to be emitting light, but the individual pixels or sub-pixels cannot be readily discerned from one another. In another embodiment, the intensity or color of a light emitting region of rhe light emitting device is controlled by spatial or temporal dithering or halftone printing. In one embodiment, the average size of the light extracting regions in a square centimeter of a light emitting region on the outer surface of the light emitting device is less than 500 microns and the color and or luminance is varied by increasing or decreasing the number of light extracting regions within a predetermined area. In one embodiment, the luminance of the light extraction region or light extraction features is less than one selected from the group: 1. 5. 10, 20, and 50 Cd m ² when viewed normal to the surface from the side with the light extraction features or the side without the light extraction feanues with the light source not emitting light and under 50 lux ambient illumination.

[68] In one embodiment, the light emitting device is a sign with a light emitting surface comprising at least one selected from the group: a light emitting region, a light exnacting region, and a light extraction feature which is not readily discernible by a person with a visual acuity between 0.5 and 1.5 arcrninutes at a distance of 20 cm when ilhuninated with 200 lux of diffuse light in front of Light Absorbing Black-Out Material from Edmimd Optics Inc. In another embodiment, the light emitting device is a sign with a light emitting siuface comprising at least one selected from the group: a light emitting region, a light extracting region, and a single light extraction feature which is not readily discernible by a person with a visual acuity of 1 arcminute at a distance of 50 cm when illiim nated with 200 lux of diffuse light in front of Light Absorbing Black-Out Material from Edmimd Optics Inc.

[69] hi another embodiment, the fill factor of the light extracting features, defined as the percentage of the surface area comprising light extracting features in a light emitting region, siuface or layer of the lightguide or film, is one selected from the group: less than 80%, less than 70%, less than 60%, less than 50%. less than 40%. less than 30%, less than 20%. and less than 10%. The fill factor can be measured within a full light emitting square centimeter surface region or area of the lightguide or film (bounded by regions in all directions within the plane of the lightguide which emit light) or it may be the average of the light emitting areas of the lightguides. The fill factor may be measured when the light emitting device is in the on state or in the off state (not emitting light). In one embodiment, in the on state, the light extracting features are visible as discontinuities seen by a person with a visual acuity of one aicminute at a distance of 10 cm when the light emitting region of the film is placed in front of a black light absorbing surface and the film lias a luminance of 100 coVm2 from light directed through the film by a light input coupler.

[70] In another embodiment, the light emitting device is a sign with a light emitting surface comprising light emitting regions wherein when the device is not emitting light, the angle subtended by two neighboring light extracting features that are visible when the device is on, at a distance of 20 cm is less than one selected from the group: 0.001 degrees, 0.002 degrees, 0.004 degrees. 0.008 degrees, 0.010 degrees, 0.015 degrees, 0.0167 degrees, 0.02 degrees, 0.05 degrees, 0.08 degrees, 0.1 degrees, 0.16 degrees, 0.2 degrees, 0.3 degrees, 0.4 degrees, 0.5 degrees, 0.6 degrees, 0.7 degrees, 0.8 degrees, 1 degree. 2 degrees, and 5 degrees. In another embodiment, the light emitting device is a sign with a light emitting surface comprising light emitting regions wherein when the device is not emitting light, the angle subtended by two neighboring light extracting features (that are which are not easily visible when the device is off when illuminated with 200 lux of diffuse light) at a distance of 20 cm is less than one selected from the group: 0.3 degrees, 0.4 degrees, 0.5 degrees, 0.6 degrees. 0.7 degrees, 0.8 degrees, 1 degree, 2 degrees, and 5 degrees.

[71] In one embodiment, the thickness of the Hghtguide or core layer at the light extraction feanire in a first direction selected from the group: perpendicular to the light emitting surface of the hghtguide, perpendicular to the optical axis of the light within the hghtguide at the light extraction feature, and perpendicular to the direction of light propagating in the hghtguide at the light extraction feature divided by the length of one or more light extraction features in a first direction parallel to the direction of light propagating in the hghtguide or parallel to the optical axis of the light within the Hghtguide is greater than one selected from the group: 1. 2, 5. 10, 15, 20, and 50.

[72] In one embodiment, the Hghtguide comprises a coating or layer disposed in optical contact with the Hghtguide comprising the light extraction features. In one embodiment, for example, a UV curable methacrylate-based coating is coated onto a plasma surface treated silicoue-based Hghtguide and is cured in when in contact with an embossing drum such that the Hght extraction features are formed on the coating on the silicone-based Hghtguide. Various UV cxuable coatings are suitable for use in this embodiment, and the refractive index, light transmission properties, adhesion properties, and scattering properties are known in the optical film industry.

[73] In one embodiment, the light extraction feature comprises a light scattering material (such as titanium dioxide, for example) and a light absorbing tint, dye or material on one or more surfaces, in the volume of the feature, or optically coupled to or adjacent to the scattering material.

VISIBLE LIGHT EXTRACTION FEATURES ALSO PROVIDING ILLUMINATION

[74] In one embodiment, the light front the light extraction features provides illiunination of an object or surface and the light extraction feamres provide a visible partem, logo, indicia or graphic. In one embodiment a first percentage of light exiting the lightguide due to the light extraction feamres illuminates a surface, object or region, and the second percentage of light exits the lightguide in a partem, logo, indicia, or graphic and is visible directly, hi another embodiment, a first percentage of light exiting a light emitting device from the first surface of the lightguide illuminates a surface, object, or region and a second percentage of light exits the light emitting device from the second surface of the lightguide opposite the first surface and the light extraction features form a visible pattern, logo, indicia, or graphic. For example, in one embodiment, a printed white ink light extraction region on one side of a lightguide with a diffuse reflectance of about 60% (measured from the air side and not througli the lightguide), reflects a first percentage (approximately 30%) of incident light out of the lightguide toward a viewing side, transmits approximately 40% through the light extraction features out of the lightguide to illuminated a product in a POP display, and approximately 30% of the reflected light remains within the lightguide.

MULTIPLE LIGHTGUIDES

[75] In one embodiment, a light emitting device comprises more than one lightguide to provide at least one selected from the-: group: color sequential display, localized diniming backlight, red, green, and blue lightgiiides, animation effects, multiple messages of different colore. NVIS and daylight mode backlight (one lightguide for NVIS, one lightguide for daylight for example), tiled lightguides or backlights, and large area light emitting devices comprised of smaller light emitting devices. REGISTRATION HOLES AND CAVITIES AND ALIGNMENT GUIDE

[76] In one embodiment, one or more of the following: lightguide. lightguide region, light mixing region, light input coupler, housing, holding device and plurality of coupling lightguides comprises at least one opening or aperture suitable for registration with another component of the device that contains at least one pin or object which may pass through the at least one opening or aperture. In another embodiment, the 'light nirning optical element has an alignment guide physically coupled to the light turning optical element such that the guide directs the coupling lightguide input surfaces to align in at least one of the following directions: a direction perpendicular to the film surface of the coupling lightguides, a direction parallel to the coupling lightguide film surfaces, a direction parallel to the optical axis of the light source, and a direction orthogonal to the optical axis of the light source.

MOTION SENSOR

[77] In another embodiment, the light emitting device comprises a motion sensor. Types of motion sensors include passive infrared sensors, active infrared sensors, ultrasonic motion sensors, and microwave motion sensors. In one embodiment, die motion sensor is disposed to receive radiation passing through the film-based lightguide or from within the film-based lightguide (such as when exterior light is redirected into the lightguide by the light extraction features and propagates through the lightguide to reach die motion sensor). In another embodiment, movement detected by the motion sensor triggers the light emitting device to change the light output characteristics. In one embodiment, the light emitting device changes its light emitting characteristics by one or more selected from the group: emittmg light in one or more light emitting regions, stopping emitting light in one or more light emitting regions, changing the overall light flux output (increase or decrease by an amount) in one or more light emitting regions, changing the angular light output profile in one or more light emitting regions, changing the color of the light output in one or more light emitting regions. For example, in one embodiment, the motion sensor triggers the light emitting device to nun on. In another example, the motion sensor triggers the light emitting device to pulse one LED off and on for a flashing logo in a first light emitting region while maintaining the light output of a second LED at a constant visible light output level in a second light emitting region. EXTRACTING LIGHT FROM THE CLADDING

[78] In one embodiment, a cladding region is disposed on or optically coupled to a core region of a lightguide and comprises a light extracting region operatively coupled to the cladding region on the side of the first cladding region opposite the lightguide that extracts light from the cladding region. For exainple, in one embodiment, the outer surface of a cladding region is rougheued or comprises surface relief features that extract light propagating in the cladding. In another embodiment, a layer or region is optically coupled to the cladding region that comprises a light extracting region. For example, in one embodiment, a black PET film is optically coupled to the core region of a lightguide using a pressure sensitive adhesive that functions as the cladding in the region.

POINT OF PURCHASE DISPLAY

[79] In one embodiment, a light emitting point of purchase (POP) display comprises a film-based lightguide, coupling lightguides. and a light input coupler. In another embodiment, die point of purchase display is a shelving system with tags, indicators, indicia. graphics, and/or other media. In another embodiment, the POP display comprises a light emitting device electrically connected to a motion sensor. In one embodiment, die light emitting device is integrated into the POP display such that one or more regions of the POP display have light emitting indicia (such as a logo, graphic, text, symbol, and/or picture). In another embodiment, the lightguide has one or more substantially transparent regions and is disposed with respect, such as in front of a region of the point of purchase display. For example, in one embodiment, a POP display comprises a printed cardboard region with a substantially transparent lightguide disposed above it. In this embodiment, for example, the red printed cardboard region is visible through the lightguide when the light emitting device is not emitting light and is visible in non-light emitting regions of the lightguide when the light emitting device is emitting light. In one embodiment, the lightguide is disposed over text regions, grapluc regions, unifoitn colored regions (red or white background for example) or other printed or imprinted regions of the display. In one embodiment, the light emitting region is used to enhance the printed region. For example, in one embodiment, the light emitting region emits red light in the fonn of indicia spelling "SALE" and is disposed above a similar size and shape printed region bf the POP display spellmg "SALE". In another embodiment, the light emitting region emits light that facilitates one or more of the following: enhances edges, outlines shapes or printed indicia, and indicates a particular product within or region of tlie POP display. In another embodiment, the light emitting region of a lightguide in a first output region is disposed above a printed region of a display or sign that lias a diffuse reflectance less than one selected from the group: 60%, 50%, 40%, 30%, 20%, 10%, and 5%. For example, in one embodiment, a light emitting device comprises a white light emitting region on a lightguide above a black printed region such that the luminance contrast ratio of tlie light emitting region is high.

[80] In another embodiment, a POP display comprises a light emitting device wherein the light emitting region of the lightguide is disposed behind a region of the display. In one embodiment, the light emitting region is disposed behind a printed graphic, logo, uniform, patterned and/or other visible region of the display and the light emitting region indicia or pattern includes one or more of the following: a high luminance contrast ratio, a high color contrast, and both a high luminance contrast ratio and a high color contrast. In order for a lightguide to be visible through a layer of the POP display, the layer should have transmittance sufficient for the light to transmit through the laya- such that the light emitting region has a sufficiently high luminance contrast ratio or color contrast. In one embodiment, a layer or region of a POP display comprising a light emitting device is disposed to receive light from the hght emitting region and transmit a portion of the hght through the layer or region having an ASTM D1003 luminous transmittance greater than one selected from the group: 2%, 5%, 10%, 20%, and 50%. hi another embodiment, the aforementioned layer or region of the POP display has an average transmittance for tlie wavelength of the light emitted from the light emitting region greater than one selected from the group: 2%, 5%, 10%, 20%, and 50%.

[81] hi one embodiment, the POP display comprises and is powered by one or more of the following: batteries, fuel cell, wired AC power from an AC cord, DC power fr om a driver, or photovoltaic power from a photovoltaic cell. In another embodiment, the POP display comprises a digital device reader that reads a device inserted into the POP display. In another embodiment, the POP display uses the information derived from a digital device by the digital device reader to determine one or more of the following: authenticity of the product, authenticity of the POP display; authenticity of the user, tlie illumination color for the display, the on/off cycle for one or more colors of the display, the time period duration for tlie light source to be on/off (dmation of sale items or daytime hours that the store is open for example), and/or other user or manufacturer information related to the light emitting properties and fimctionality of tlie POP display, hi one emboduueut. the digital device comprises one or more of the following: microchip, microprocessor, microcontroller, integrated circuit, computer circuit, memory (flash memory, for example), a computer, a digital storage device (memory, flash memory, hard drive. CDROM, DVD DRO , etc.), radio frequency tag, and an electronic information carrying device. For example, in one embodiment, the POP display comprises a radio frequency reader and an RF tag is disposed near the reader such that POP display reads the information from the RF tag and the light output appropriately modified. In this embodiment, the product manufachire could send the appropriate RF ID tag to illuminate a certain pan of the display (the region of the display comprising the indicia reading "20% off' for example) rather than another region of the display (the region that reads "'10% OFF" for example). In another embodiment, the POP display comprises a radio frequency transceiver that allows the display to coininunicate with a remote server to determine the optical output for the display. For example, in one embodiment, the POP display comprises a microcontroller and an IEEE 802.11 wireless radio that communicates with a server to determine the correct light output for a particular product at a particular location and rime.

POP DISPLAY PROVIDES PRODUCT ILLUMINATION

[82] In one embodiment, a POP display comprises a hght emitting device including a lightguide diat disuibutes light from a light input coupler to provide illumination to one or more regions designed to hold products. In another embodiment, the POP display comprises a light emitting device including a lightguide that disuibutes light from a light input coupler to provide illumination to one or more products within the POP display. For example, in one embodiment, a POP display comprises a light emitting device comprising a light input coupler wherein light from an LED is directed into the input ends of an array of coupling lightguides. The light propagates within the coupling lightguides and into a lightguide region. One or more light emitting regions are defined within the lightguide region proximate the products (such as the underside of a shelf above products where the light emitting region directs hght down toward the products). In one embodiment, the lightguide comprises one or more light emitting regions for illuminating more than one product or area. In another embodiment, the lightguide region comprises a substantially linear region disposed to illuminate a linear array of products. For example, the light emitting region could be in the shape of a long thin rectangular "line" of light on the underside of a shelf emitting light downwards toward a horizontal array of products. In this embodiment, the shelf may be substantially opaque such that the line of light is not directly visible under normal POP display viewing siniations. In another embodiment, the light emitting region of a lightguide region of a film-based lightguide of a light emitting POP display is disposed vertically along a vertical structure of a POP display such that the "line" of light from the long thin rectangular light emitting region illuminates the outer front surfaces of a vertical array of products. In one embodiment, the POP display comprises any suitable number of light emitting devices, such as one, two. three, or more separate light emitting devices, to provide light for one or more of the following: light emitting indicia, illumination of the products or region near the products, and distributing light into the products. For example, in one embodiment, the POP display comprises a light emitting device for illuminatiiig the products and an additional light emitting device for providing light emitting indicia or graphics. In another example, a light emitting device comprises a light source and an array of coupling lightguides that transmit light to first and second lightguide regions that provide product illumination and light emitting indicia, respectively. In another embodiment, a POP display comprises a sensor that detects the presence or absence of one or more products. By using a sensor, such as a photocell or mechanical switch, power can be reduced and saved when there are no products. For example, in one embodiment, a POP display comprises a mechanical switch at the back of the display with slightly angled shelves. Any product in the display would slide to the back and press against the switch, thus indicating that the light source for the light emitting POP display should be ninied on. In another embodiment, a photodetector at the back of the POP display is designed to nirn on the light source for the light emitting POP display when a shadow is detected, signifying that a product is disposed between an ambient or internal light source and the photodetector.

[83] In one embodiment, the light emitting device is disposed on a viewing side of an object or region of a container (such as a cooler point of purchase display) and provides illumination through light exiting a region substantially longer than it is wide (similar to a strip) disposed along a top edge, bottom edge, side edge, or along the top, bottom, or side of a shelf. For example, in one embodiment, the light emitting device has a substantially rectangular light emitting strip disposed along the side frame area between doors in a transparent cooler (such as used for displaying drinks in a convenience store). In this embodiment, the thin lightguide in a narrow snip form provides illumination of the objects in the cooler without the light from the strip being visible from outside the cooler. In this embodiment, for example, the light emitting device can be built into the door. In another embodiment, for example, the light emitting strip is disposed along the underside of a shelf and provides illumination of the products below the shelf. In a further embodiment, the light emitting strip is disposed on the top side of a shelf (or disposed underneath the top surface and emitting liglit out of the top surface through a shelf with a transparent region). In the aforementioned embodiment, the liglit emitting strip may be disposed parallel to the shelf such that it ilhiminates a row of products (parallel to the shelf) or it may be oriented at an angle approximately 90 degrees from the shelf, door, or viewing region such that it illuminates a column of products. For example, in one embodiment, a light emitting device comprises a strip emitting red light disposed in a cooler on a shelf beneath a liglit transmitting acrylic sheet that illuminates a column of red colored carbonated beverages in transparent plastic bottles. The red light in this embodiment provides a glowing red illirmiuarion of the bottles.

LIGHT EMITTING DEVICE THAT DISTRIBUTES LIGHT TO BE EMITTED FROM PRODUCTS

[84] hi one embodiment, a liglit emitting device comprises a liglit distribution system that receives light from a light input coupler, transmits the light through a lightguide to light emitting regions, wherein products placed in proximity to the light emitting regions receive the liglit from the light emitting region and emit the light in a predetermined location of the packaging or product. In one embodiment, the product is located on a shelving system, rack. display, platform or point of purchase display. For example, in one embodiment, a POP display comprises a light input coupler that directs light from a light source into coupling lightguides that are extensions from a lightguide. The lightguide comprises first light emitting regions disposed along a first or vertical wall of the display. The first liglit emitting regions are disposed to emit light in regions corresponding to light receiving input surfaces of products vertically stacked in the POP display. In one embodiment, the products comprise a lightguide with coupling lightguides disposed to receive light from the first light emitting region, transnut the light througli a lightguide and exit the lightguide in a liglit emitting region of the lightguide comprising light extraction features. For example, when the light emitting device of the previous example is turned on and products stacked vertically in the POP display, light exits the first light emitting region and propagates into die product and is emitted from a second light emitting region ilhumnating the text "NEW AND IMPROVED," for example. When the product is removed from the shelf, the light emitting region of the product stops emitting light. Thus, in this example, each product can be illuminated without requiring hght sources, electronics, batteries, etc. within each product. In another embodiment, the product uses a lightguide and does not comprise coupling lightguides. For example, the light receiving region of the product may comprise a light scattering region disposed behind a light transmitting lightguide such that a portion of the light from the light emitting region of the POP display passes through the lightguide, reaches the scattering region on the back side of the lightguide, is reflectively scattered into the lightguide in a waveguide condition, and propagates to light emitting regions disposed on a second side of the packaging such that light is emitted in the fonn of liglit eihitting indicia or graphics.

[85] hi one embodiment, the liglit enntting region has a low luminance contrast ratio or low color contrast when the product is removed from the POP display. For example, a light eiiutting region comprises surface relief liglit extraction features of nicro-indentations into a transparent lightguide of sizes less than 100 microns in one or more directions and spaced more than about 100 microns apart may not be readily discernible under some illumination conditions and the print or packaging below the light emitting region (looking through the lightguide) using ambient liglit is readily discernible or sufficiently uniform, hi this example, when light is input into the lightguide of the product, a portion of the light exits the light emitting region such that an image, logo, indicia, graphic or other pattern is visible and when the product is removed from the POP display it disappears, hi another embodiment, the color of the light extraction feaaire in the liglit emitting region is substantially the same as the region beneath the feature. For example, a red ink liglit extraction feature disposed on the product side of a lightguide in a light emitting region disposed in front of a red region of the packaging will maintain the red appeaiauce when Uluminated with ambient hght when removed from the POP display.

[86] hi another embodiment, a shelf (such as a grocery store shelf) comprises light emitting regions on the top side of the shelf such that when products are disposed on top of the light emitting regions, the products "liglit up" (have light emitting regions) or have hght emitting indicia or graphic regions. When a product is removed from the shelf, the product does not receive light from the first light ernitting region and the liglit emitting from the product is reduced or ehminated. In another embodiment, a portion of the ambient light is reflected fr om the package in the hght emitting region or ambient light is transmitted through the lightguide in the product to provide illumination to indicia or graphics. [87] In one embodiment, the product further comprises a light output window disposed to permit a portion of the incident light to propagate into a second product. For example, in the preceding example, a product stacked on another product would not directly receive light from the light emitting regions on the shelf below. In another embodiment, the product comprises one or more of the following: a lightguide, coupling lightguide, cavity, hole, or light transmitting optical element that permits or directs light from one light receiving region of the product to a light transmitting region of the product such that when a second product is disposed and aligned upon the first product, the second product emits light through second light emitting regions or indicia. OTHER APPLICATIONS AND FUNCTIONALITY OF THE LIGHT EMITTING DEVICE

[88] In one embodiment, the light emitting device comprises a light input coupler, lightguide, and light source which provide il unination for translucent objects or film such as stained glass windows or signs or displays such as point-of-purchase displays. In one embodiment, the thin film enables the light extraction features to be printed such that they overall negligibly scatter light that propagates normal to the face of the film. In this embodiment, when the film is not illuminated, objects can be seen clearly through the film without significant haze. When placed behind a transparent or partially transparent stained glass window, the overall assembly allows low-scattering transmission of light through the assembly if desired. LUMINANCE CONTRAST RATIO OF THE LIGHT EMITTING REGION

[89] The luminance contrast ratio of the light emitting region may be measured under specific light conditions to ascertain the visibility of the light emitting indicia or region. The desired visibility of the light emitting region (whether emitting light in the on-state or not emitting light in the off-state) may vary depending on the application and desired appearance of the light emitting device. The perceived visibility of the light emitting region under different ambient light conditions can be measured by the luminance contrast ratio. The luminance contrast ratio is the ratio of the luminance of the liglit enritting region to the luminance of the neighboring region under specific ambient liglit levels. For high ambient liglit levels, the peak illuminance of the liglit emitting region and the neighboring region is greater than 100 lux. For low ambient light levels, the peak illuminance of the light emitting region and the neighboring region is less than 100 lux. For a spot measurement area, the measurement spot size may be from 1 nun ² to 10 cm ² , with a typical 1 cm ² circular spot measurement. For light emitting regions comprising small text font size, for example, the liglit emittmg region measurement spot size may be 1 mm ² . For large emitting regions with a continuous light emitting partem, the light emitting region measurement spot size may be, for example, 10 cm ² or a 9 point average of 1 cm ² spot sizes. In one embodiment the light emitting region is visibly perceived as a continuous light emitting region representing text, graphics, logos, a uniform partem, etc. and is comprised of smaller light extraction feamres that are not readily discerned without close inspection. In this example, the luminance contrast ratio may be measured in the perceivable characteristic region that represents the logo or perceived pattern. For example, when standing in front of a POP display, the text "SALE" may be perceived and upon closer inspection, the bend in the middle region of the "S" comprises a collection of light extiaction features extracting hght in-between regions that do not extract light. In this embodiment, the luminance measurement for the light emitting region should have a spot size less than size of the bend in the middle region of the "S" and large enough to encompass at least about 4 or more light extraction features. The luminance contrast ratio in this example is the luminance of the middle region of the "S" divided by the luminance of the substantially non-light emitting region near the ^* 'S".

[90] A high luminance contrast ratio is desired when the sign, graphic, logo, or light emitting region should be perceived over the neighboring area or region. For example, an exit sign should be perceived when emitting light in the light emitting indicia forming the text "EXIT" such that the sign is readily visible, hi some applications, it is desirable that die light emitting region have a low huninance contrast ratio when the light emitting region does not emit light. For example, one may desire that a cooler door sign be very visible when illuminated, but substantially transparent when not illuminated. In another embodiment, the luminance of the light emitting region in ambient light depends on one or more properties selected from the group: the type of the light extraction features, the reflectance of the light exnaction featuies. the size of die light extraction features, the shape of die hght extiaction features, the density of the light extraction features, the thickness of the light extiaction features, other films or components disposed in front of the liglit emitting region, other films or components disposed in behind the hght emitting region, the ambient light illuminance from the front of the liglit emitting region, and the ambient light illuminance from behind the light emitting region. In another embodiment, the hght emitting region does not require a high huninance contiast ratio in high ambient liglit environments because it is nonnally used in low ambient light environments. For example, a sign or display in a low ambient light level restaurant does not necessarily need a high contrast ratio in a high ambient light environment. In another embodiment, the light emitting region is designed to primarily display the light emitting indicia when in low ambient light level environments. For example, an exterior sign painted red may be readily visible during the day but needs supplemental lighting (of the red paint) or light emitting indicia (displaying the same indicia) at night to be readily seen.

[91] In another embodiment, for example, a low luminance white light emitting indicia region of a substantially transparent lightguide disposed in front of a white region of a POP display may not be very visible in a bright ambient light environment, but will be more visible in a very low ambient light environment, hi this embodiment, the region of die POP comprising the light emitting region has a low Liiminance Connast Ratio, On-state, High Ambient Light and a high Luminance Contrast Ratio, On-state, Low Ambient Light. In another embodiment, the light emitting region has a low himinance contrast ratio in the off- state in low and high ambient light levels and has a high luminance contrast ratio in the on- state in low and high ambient light levels.

[92] The luminance contrast ratio needed for a particular task (such as viewing a sign or display) may depend on the ambient environment, the individual viewing the sign, arid the color of the light emitting region and the neighboring region. In one embodiment, the luminance contrast ratio of the light eiiutting region in the on-state (emitting light in the region) for a low ambient light level, high ambient light level, or both is greater than one selected frotn the group: 1, 2, 5, 10, and 20. In another embodiment, the himinance contrast ratio of the light emitting region in the off-state (not emitting light in the region) for a low ambient light level, high ambient light level, or both is greater than one selected from the group: 2, 5. 10, and 20.

[93] In some applications, the luminance contrast ratio of the hght emitting region may not need to be high. For example, if the light emitting region serves only to accent or supplement the outline or feature of the printed indicia it is placed in front of or behind. In a fiuther embodiment, the luminance contrast ratio of the light emitting region in the on-state (emitting light in the region) for a low ambient light level, high ambient light level, or both is less than one selected from the group: 2. 5, 10, and 20. In a another embodiment, the luminance contrast ratio of the light emitting region in the off-state (not ermtting light in the region) for a low ambient light level, high ambient light level, or both is less than one selected from the group: 2, 5, 10, and 20. COLOR CONTRAST OF THE LIGHT EMITTING REGION

[94] The contrast of a sign, display or light emitting display is also be dependent on the color of the light emitting region and the neighboring region. For example, red light emitting indicia on a transparent lightguide may have the same luminance as the green background under standard illiuninant A illumination, but the color contrast is significantly greater. The color contrast of the Ught emitting region, as defined herein, is the length of the line between the color of the light emitting region and the neighboring region, Διι'ν', measured on the 1976 u', v' CIE Uniform Chromaticity Scale when illuminated by an Illiuninant A standard illiuninant. The measurement spot size for the color contrast may be ascertained the same way as described above for the luminance contrast ratio. The color contrast may be measured under high and low ambient light levels as described above for the luminance contrast ratio. The typical color contrast, AuV, needed to perceive two colors adjacent each other is 0.004. However, for some applications, the contrast ratio is desired to be higher to provide increased visibility and perception against the background. The color contrast may be low or high in the off-state and be the opposite in the on-state. For example, a light enutting region may be designed to be the same color as the background by using white ink light extraction features on a transparent lightguide when placed above a white region of a POP display. In this example, when the light emitting region emits light from a red LED, the color contrast of the light emitting region is significantly higher than when the light emitting region emits white light.

[95] hi some applications, for example, the color contrast may be desired to be low in the on state or off state such that the light emitting indicia matches the background. For example, a POP display may be designed to have a matching color contrast when on where red light emitting indicia match the color of the display in the on-state, and when the light emitting indicia are turned off, the black background beneath the indicia provides a high color contrast. Similarly as with the luminance contrast ratio, the color contrast may be designed to high or low under low or high ambient light levels depending on the application and desired visibility in either state under the lighting conditions.

[96] In one embodiment, the color contrast of Hie light emitting region in the on-state (emitting light in the region) for a low ambient light level, high ambient light level, or both is greater than one selected from the group: 0.004. 0.01, 0.04. and 0.1. In another embodiment, the color contrast of the light emitting region in the off-state (not enutting light in the region) for a low ambient light level, high ambient light level, or both is greater than one selected from the group: 0.004, 0.01, 0.04, and 0,1. In another embodiment, the color contrast of the light emitting region in the on-state (emitting light in the region) for a low ambient light level, high ambient light level, or both is less than one selected from the group: 0.004, 0.01, 0.04, and 0.1. In a another embodiment, the color conhast of the light emitting region in the off-state (not emitting light in the region) for a low ambient light level, high ambient light level, or both is less than one selected from the group: 0.004, 0.01 , 0.04, and 0.1.

METHOD OF MANUFACTURING LIGHT INPUT/OUTPUT COUPLER

[97] In one embodiment, the lightguide and light input or output coupler are formed from a light transmitting film by creating segments of the film corresponding to the coupling lightguides and translating and bending the segments such that a plurality of segments overlap. In a further embodiment, the input surfaces of the coupling lightguides are arranged to create a collective light input siuface by translation of the coupling lightguides to create at least one bend or fold.

[98] In another embodiment, a method of manufacftiring a lightguide and light input coupler comprising a light transmitting film with a lightguide region continuously coupled to each coupling lightguide in an anay of coupling lightguides, said array of coupling lightguides comprising a first linear fold region and a second linear- fold region, comprises the steps: (a) increasing the distance between the first linear fold region and the second linear fold region of the array of coupling lightguides in a direction perpendicular to the light transmitting film surface at the fust linear fold region; (b) decreasing the distance between the first linear fold region and the second linear fold region of the array of coupling lightguides in a direction substantially perpendicular to the first linear fold region and parallel to the light transmitting film surface at the fust linear fold region; (c) increasing the distance between the first linear fold region and the second linear fold region of the anay of coupling lightguides in a direction substantially parallel to the first linear fold region and parallel to the light transmitting film surface at the first linear fold region; decreasing the distance between the first linear fold region and the second linear fold region of the anay of coupling lightguides in a direction perpendicular to the light transmining film surface at the first linear fold region: (d) such that the coupling lightguides are bent, disposed substantially one above another, and aligned substantially parallel to each other. These steps (a), (b), (c) and (d) do not need to occur in alphabetical order and the linear fold regions may be substantially parallel. RELATIVE POSITION MAINTAINING ELEMENT

[99] In one embodiment, at least one relative position maintaining element substantially maintains the relative position of the coupling lightguides in the region of the first linear fold region, the second linear fold region or both the first and second linear fold regions. In one embodiment, the relative position maintaining element is disposed adjacent the fust linear fold region of the array of coupling lightguides such that the combination of the relative position maintaining element with the coupling lightguide provides sufficient stability or rigidity to substantially maintain the relative position of the coupling lightguides within the first linear fold region during translational movements of the first linear fold region relative to the second linear fold region to create the overlapping collection of coupling lightguides and the bends in the coupling lightguides.

PACKAGING

[100] In one embodiment, a kit suitable for providing illumination comprises a light source, a light input coupler, and a lightguide. FILM PRODUCTION

[101] In one embodiment, the film or lightguide is one selected from the group: extruded film, co-extruded film, cast film, solvent cast film, UV cast film, pressed film, injection molded film, knife coated film, spin coated film, and coated film. In one embodiment, one or two cladding layers are co-extruded on one or both sides of a lightguide region.

SEPARATE COUPLING LIGHTGUIDES

[102] In another embodiment, the coupling lightguides are discontinuous with the lightguide and are subsequently optically coupled to the lightguide. In one embodiment, the coupling lightguides are one selected from the group: extruded onto the lightguide, optically coupled to the lightguide using an adhesive, optically coupled to the lightguide by injection molding a light nansnntting material that bonds or remains in contact with the coupling lightguides and lightguide. thermally bonded to the lightguide. solvent bonded to the lightguide, laser welded to the lightguide, sonic welded to the lightguide. chemically bonded to the lightguide, and otherwise bonded, adliered or disposed in optical contact with the lightguide. LIGHT EXTRACTION FEATURES

[103] In one embodiment, the light extraction features are disposed on or within a film, lightgiiide region or cladding region by embossing or employing a "knurl roll" to imprint surface features on a surface. In another embodiment,, the light extraction features are created by radiation (such as UV exposure) curing a polymer while it is in contact with a drum, roll, mold or other surface with surface features disposed thereon. In another embodiment, light extraction features are formed in regions where the cladding or low refractive index material or other material on or within die lightgiiide is removed or formed as a gap. In another embodiment, the lightguide region comprises a light reflecting region wherein light extraction features are formed where the light reflecting region is removed. Light extraction may comprise or be modified (such as the percent of light reaching the region that is extracted or direction profile of the extracted light) by adding scattering, diffusion, or other surface or volumetric prismatic, refracting, diffracting, reflecting, or scattering elements within or adjacent the light extraction features or regions where the cladding or other layer has been removed.

[104] In one embodiment, the light extraction features comprise an ink or material within a binder comprising least one selected from the group: titanium dioxide, barium sulfate, metal oxides, microspheres or other non-spherical particles comprising polymers (such as PMMA, polystyrene), rubber, or other inorganic materials. In one embodiment, the ink or material is deposited by one selected from the group: thermal inkjet printing, piezoelectric inkjet printing, continuous inkjet printing, screen printing (solvent or UV), laser printing, sublimation printing, dye-sublimation printing, UV printing, toner-based printing, LED toner printing, solid ink piinting, thermal transfer printing, impact printing, offset printing, rotogravure printing, photogravure printing, offset piinting, flexographic printing, hot wax dye transfer printing, pad piinting, relief piinting, letterpress piinting, xerography, solid ink piinting, foil imaging, foil stamping, hot metal typesetting, in-mold decoration, and in-mold labeling.

[105] In another embodiment, the light extraction features are formed by removing or altering the surface by one selected from the group: mechanical scribing, laser scribing, laser ablation, surface scratching, stamping, hot stamping, sandblasting, radiation exposure, ion bombardment, solvent exposure, material deposition, etching, solvent etching, plasma etching, and chemical etching. [106] In a further embodiment, the light extraction features are formed by adding material to a surface or region by one selected from the group: UV casting, solvent casting with a mold, injection molding, thermoforming, vacuum forming, vacuum thermofonning, and laminating or otherwise bonding, and coupling a film or region comprising smface rehef or volumetric features.

[107] In one embodiment, at least one selected from the group: mask, tool, screen, patterned film or component, photo resist, capillary film, stencil, and other patterned material or element is used to facilitate the transfer of the light extraction feamre to the lightguide. film, lightguide region, cladding region or a layer or region disposed on or within the lightguide.

[108] Following is a more detailed description of various embodiments illustrated in FIGS 1-11.

[109] FIG 1 is a top view of one embodiment of a Ught emitting device 100 comprising a light input coupler 101 disposed on one side of a film-based lightguide. The light input coupler 101 comprises coupling lightguides 104 and a light source 102 disposed to direct light into the coupling lightguides 104 through a light input surface 103 comprising one or more input edges of the coupling lightguides 104. In one embodiment, each coupling lightguide 104 terminates at a bounding edge. Each coupling lightguide is folded such that the bounding edges of the coupling lightguides are stacked to form the light input surface 103. The light emitting device 100 further comprises a lightguide region 106 comprising a light mixing region 105, a lightguide 107, and a light emitting region 108. Light from the light source 102 exits the light input coupler 101 and enters ^' the lightguide region 106 of the film. This light spatially mixes with light from different coupling lightguides 104 within the light mixing region 105 as it propagates through the lightguide 107. In one embodiment, light is emitted from the lightguide 107 in the light emitting region 108 due to light extraction features (not shown).

[110] FIG 2 is a perspective view of one embodiment of a light input coupler 200 with coupling lightguides 104 folded in the -y direction. Light from the light source 102 is directed into the light input surface 103 comprising input edges 204 of the coupling lightguides 104. A portion of the light from the Ught source 102 propagating within the coupling lightguides 104 with a directional component in the +y direction will reflect in the +x and -x directions from the lateral edges 203 of the coupling lightguides 104 and will reflect in the +z and -z directions from the top and bottom surfaces of die coupling lightguides 104. The light propagating within the coupling lightguides is redirected by the folds 201 in the coupling lightguides 104 toward the -x direction

(111) FIG 3 is a perspective view of one embodiment of a light emitting point of purchase (POP) display 1700 comprising printed indicia 1702 on a surface layer 1730 of the POP display 1700. In this embodiment, the light enutting indicia 1001 emits light from the lightguide 106 that visible through the surface layer 1730 of the POP display 1700. For example, in one embodiment, the POP display 1700 comprises a suitable material, such as cardboard, with printed indicia and the lightguide region 106 comprises printed light extraction features on a surface of the lightguide region 106 such that the light emitted from the lightguide region 106 passes thiough the cardboard and is visible. In another embodiment, the lightguide region 106 is disposed on an outer surface of the POP display 1700 and the liglit emittmg indicia 1001 is visible directly when illuminated.

[112] FIG 4 is a perspective view of one embodiment of a point of purchase (POP) display 1703 comprising the printed indicia 1702 on die surface layer 1730 and the luminous light emitting indicia 1001 emitting liglit from the first lightguide region 106 and visible through the surface layer 1730. In this embodiment, a second input coupler 1704 comprises a light source (not shown in FIG 4) and a second lightguide 1705 defining a first hght emitting region 1706 and a second light emitting region 1708 disposed to emit light thiough apertures 1707 in the POP display 1703 toward an interior volume or region 1760 of the POP display 1703. The interior region 1760 is configured to contain one or more products for display. For example, in one embodiment, the light emitted from the first light emitting region 1706 and the liglit emitted from the second liglit emitting region 1708 illuminate the products such that the products are more clearly visible, the packaging distinct or more legible, and/or enhanced through supplemental illumination. In another embodiment, the POP display 1703 provides distribution of liglit thiough the first light emitting region 1706 and the second light emitting region 1708 to be coupled into and emitted from a product.

[113] FIG 5 is a perspective view of the POP display 1703 shown in FIG 4 further comprising one or more products 1710 with packaging (two products 1710 are shown in FIG 5). The POP display 1703 includes a lightguide 1705 having a first liglit emitting region 1706 and a second light emitting region 1708 on a first side of the POP display 1703. In the embodiment shown, the light emitted fiom the fiist light emitting regions 1706 and the light emitted from the second hght emitting region 1708 passes into the products 1710 and is emitted from the products 1710 in the form of liglit emitting indicia 1715. For example, as shown in FIG 5, the products 1715 are boxes of candy that comprise coupling lightguides (shown in FIG 6) that receive light from the first light emitting region 1706 or second light emitting region 1708 and transinit the light out of the product 1710 in the form of light enntfing indicia 1715. In this manner, the product can appear luminous without requiring any light sources or power supplies within the product. Othe products, for example, include without limitation, food or grocery items in cardboard, paper, metal, or plastic packages, toothpaste products, cereal products, potato chip bags, goods^ cereals, soft drinks in cans, and water in bottles. The coupling lightguides (shown in FIG 6) for the products/packages may be placed in a range of packaging materials and may be disposed on the inner region of the package, the outer region of the packaging, or within the packaging material.

[114] FIG 6 is a perspective view of the POP display 1703 comprising products 1710 shown in FIG 5 and illustrating a path of light through the POP display 1703 and products 1710. The products 1710 comprise coupling lightguides 1709 and a lightguide 1711. Light 1712 from the light input coupler 1704 propagates through the lightguide 1705 in the +y direction and then in the +z direction and exits the lightguide 1705 at the second light emitting region 1708 propagating in the -y direction and is coupled into coupling lightguides 1709 in the product 1710. The light 1712 then propagates through the coupling lightguides 1709 in the product 1710 in the -x direction and is directed into the lightguide 1711 propagating in the -y direction within the product 1710 until the light is extracted from the lightguide 1711 by light extraction feanires (not shown) and exits the product 1710 with a component in the -x direction in the form of light emitting indicia 1714. Light 1713 from the light input coupler 1704 propagates through the lightguide 1705 and exits the lightguide 1705 at the first light emitting region 1706 and is coupled into coupling lightguides 1709 in the product 1710. The light 1713 then propagates through the coupling lightguides 1709 in the product 1710 and within the lightguide 1711 within the product 1710 until the liglit is emitted from individual liglit extraction features (not shown) o the lightguide 1711 that collectively form light emitting indicia 1715.

[115] FIG 7 is a perspective view of the product 1710 shown in FIG 5 comprising printed indicia 1716 on one or more outer surfaces of the packaging 1719 arid a stacked array of coupling lightguides 1709 with the light input surface 103 comprising the light input edges 204 of the coupling lightguides 1709 disposed to receive light and transmit the light into the lightguide 1711 positioned within an interior region of the packaging 1719 of the product 1710. The liglit is then extracted from the lightguide 1711 to exit the product 1710 by light extraction features (not shown) on, within, or optically coupled to the Ughtguide 1711 where the light emitted from the packaging 1719 and product 1710 due to the light extraction features collectively form light emitting indicia 1717.

[116] FIG 8 is a perspective view of one embodiment of a product 1720 disposed to receive light 1712 from a light emitting device 1703 (shown in FIG 5) with a component in the -y direction, transmit the light through a Ughtguide 1722 in the -x direction, and then the -y direction to a second region 1780 of the product 1720 where the light is emitted with a component in the -x direction in the form of light emitting indicia 1716. The product 1720 can be used in the POP display 1703 illustrated in FIGS 5 and 6. As shown in FIG 8, light 1712 (also shown in FIG 6) from the light emitting region 1708 (shown in FIG 6) of the Ughtguide 1705 in the POP display 1703 propagating in the -y direction is transmitted through an input window 1721 in the packaging 1719, transmitted tlirough the Ughtguide

1722 and is reflectively scattered in the +y diiection and -x direction from one of the light scattering features 1724 back into the Ughtguide 1722 in a waveguide condition. The light 1712 propagates through the Ughtguide 1722 in the -x direction and then the +y direction and exits a different side 1780 of the product 1720 than the light entered with a directional component in the -x direction when the Ught reaches a light extraction feature (not shown), fonning part of the light emitting indicia 1716.

[117] FIG 9 is a perspective view of one embodiment of a first product 1728 and a second product 1729 stacked upon each other and disposed to receive light 1712 from the POP display 1703 (shown in FIG 6) propagating in the -y direction. The first product 1728 and the second product 1729 comprise lightguides 1722 disposed to receive light passing through a light input window 1721 in the packaging 1719, and the light output windows 1726 in the packaging 1719. Light 1727 propagating in the -y diiection incident on the first product 1728 passes tlirough the input window 1721, through the Ughtguide 1722 in a region

1723 without light extraction features, passes through the first product 1728 and exits the first product 1728 through the light output window 1726 in the packaging 1719. This light 1727 propagating in the -y direction is transmitted through an input window 1721 in the packaging 1719 of the second product 1729, transmitted through the Ughtguide 1722 and is reflectively scattered in the +y direction and -x direction from one of die Ught scattering features 1724 back into die Ughtguide 1722 in a waveguide condition. The light 1727 propagates tlirough the Ughtguide 1722 in the -x direction and then the +y diiection and exits a different side of the first product 1728 than die light 1727 entered with a directional component in the -x direction when the light 1727 reaches a light extraction feature (not shown). The light is extracted from the second product 1729 where the hght collectively combines from other light scattering features to form pail of the light emitting indicia 1716. The light 1727 propagating in the -y direction received from the POP display 1703 (shown in FIG 6) propagating in the -y direction is transmitted through an input window 1721 in the packaging 1719 of the fust product 1729, transmitted through the lightguide 1722 and is reflectively scattered in the +y direction and -x direction from one of the light scattering feamres 1724 back into the lightguide 1722 in a waveguide condition. The light 1712 then propagates through the lightguide in the -x direction and then the +y direction and exits a different side of the first product 1729 than the light 1712 entered with a directional component in the -x direction when the light 1712 reaches a hght extraction feature (not shown). The light is extracted from the second product 1729 where the light collectively combines from other light scattering feamres to form part of the light emitting indicia 1716 of the first product 1728. In another embodiment, the lightguide 1722 is disposed on an outer surface 1760 of the packaging 1719 in the region of the light emitting indicia 1716.

[118] FIG 10 is a cross-sectional side view of one embodiment of a light enntting device 2020 comprising the hght input coupler 101 (shown in phantom lines) and the lightguide region 106 with a reflective optical element 2021 disposed adjacent a surface 2050 of the cladding region 602 and a light source 2022 emitting light with a directional component in the +y direction disposed to direct light into the coupling lightguides 104. Light from the light source 2022 propagates through the coupling lightguides 104 widiin the light input coupler 101 and dirough the light mixing region 105 and the light emitting region 108 within the lightguide region 106. A first portion of light 2024 reaching the light extraction feamres 1007 is redirected toward the reflecting optical element 2021 at an angle such that the light escapes the lightguide region 106, reflects from the reflective optical element 1101, passes back through the lightguide region 106, and exits the lightguide region 106 through the light emitting surface 2023 witliin the light emitting region 108. A second portion of hght 2025 reaching the light extraction features 1007 is redirected toward the light emitting surface 2023 at an angle less than a critical angle, escapes the lightguide region 106. and exits the lightguide region 106 through the light emitting surface 2023 within the light emitting region 108.

[119] FIG 11 is a block diagram of an exemplary method 10500 of manufacturing a packaging for a product. A pliuality of coupling lightguides are formed in a film continuous with a liglitguide region of the film 10501. At least oue light extraction feaftue is arranged within a light emitting region defined by the lightguide region 10502. At least one coupling liglitguide of the plmaiity of coupling lightgiiides is folded such that ends of the plmaiity of coupling lightguides form a stack defining a light input surface, wherein light received by the light input surface propagates through the lightguide region by total internal reflection and exits the liglitguide region in the light emitting region 10503.

[120] In one embodiment, a packaging for a product is provided. The packaging includes a film-based lightguide having a light input surface disposed to receive light propagating orthogonal to the light input surface, and a light emitting region defined by the film-based lightguide including at least one light extraction feature. Light received by the light input surface propagates through the film-based lightguide by total internal reflection and exits the film-based lightguide in the light emitting region.

[121] In certain embodiments, the packaging comprises a film having a thickness not greater than 0.5 millimeters. In a further embodiment, the packaging comprises a first side and a second side different from the first side, wherein the light input surface is coupled to the first side and the light emitting region is defined on the second side, hi another embodiment, the light emitting region is substantially transparent when not illuminated by light propagating through the film-based liglitguide. In another embodiment, the light emitting region has a hirninance less than 50 Cd ni2 when not illuminated by light propagating through the film-based lightguide and illuminated by 50 lux of ambient light. In another embodiment, the at least one light extraction feamre has an average largest dimensional size in a plane parallel to the light emitting region less than 100 microns. In another embodiment, the packaging is formed into a container defining a region or volume, and the light emitting region of the film-based lightguide is positioned inside or within the region or volume. In a further embodiment, the packaging is formed into a container defining a volume, and the light emitting region of the film-based lightguide is positioned outside of the volume, hi a further embodiment, die packaging is formed into a container for housing the product and the film-based lightguide forms a translucent surface. In another embodiment, the packaging comprises a printed layer defining a light input window positioned to transmit Ught into the light input surface when the packagiug is formed into a container. In a fiirther embodiment, a point of purchase display comprises the packaging as described herein and a light source positioned to input light into the light input surface. [122] In another embodiment, a packaging for a product is provided. The packaging includes a lightguide defining a lightguide region. An array of coupling lightguides are continuous with the lightguide region. Each coupling lightguide terminates in an edge and each coupling lightguide is folded such that the edges of the array of coupling lightguides fonn a stack defining a light input surface. A light emitting region is defined within the lightguide region by at least one liglit extraction feamre. Liglit received by the light input surface propagates through the lightguide region by total internal reflection and exits the lightguide region in the light emitting region, hi certain embodiments, die lightguide comprises a film having a thickness . ^' not greater than 0.5 millimeters. In a further embodiment, the liglit emitting region is substantially transparent when not illuminated by liglit received by the light input surface propagating through the lightguide region. In a further embodiment, the light emitting region has a luminance less than 50 Cd/m2 when not ilhiminated by light received by the light input surface propagating through the lightguide region and illuminated by 50 lux of ambient light. In another embodiment, the at least one liglit extraction feature has an average largest dimensional size in a plane parallel to the light emitting region less than 100 microns. In another embodiment, the packaging is formed into a container for housing the product and the lightguide forms a translucent surface. In a further embodiment, the packaging is formed into a container defining a region or volume, and the light emitting region is positioned inside or within die region or volume, hi another embodiment, the packaging is formed into a container defining a region or volume, and the light emitting region of the lightguide is positioned outside of the region or volume. In another embodiment, die packaging further comprises a printed layer defining a liglit input window positioned to transmit external light into the light input surface when the packaging is formed into a container. In another embodiment, a point of purchase display comprises a packaging including a film-based lightguide and a light source positioned to input light into the light input surface. In another embodiment, a point of purchase display includes a liglitgiiide comprising a film.

[123] In another embodiment, a method of manufacturing a packaging for a product is provided. The method includes fonning a plurality of coupling lightguides in a film continuous with a lightguide region of the film, arranging at least one light extraction feature within a liglit eminmg region defined by die liglitgiiide region, and folding at least one coupling lightguide of the plurality of coupling lightguides such that ends of the plurality of coupling lightguides fonn a stack defining a light input surface. Liglit received by the light input surface propagates through the lightguide region by total internal reflection and exits the lightguide region in the light emitting region. In one embodiment, the method further comprises coupling a printed layer to the film. In further embodiment, the method further comprises forrning the packaging into a container such that the light input surface and the light emitting region are positioned on different sides of die container.

EXAMPLES

[124] Certain embodiments are illustrated in the following example(s). The following examples are given for the puipose of illustration, but not for lirniting die scope or spirit of the invention.

[125] In one embodiment, coupling lightguides are formed by cutting strips at one or more ends of a film which forms coupling lightguides (strips) and a lightguide region (remainder of the film). On the free end of the strips, the strips are bundled together into an arrangement much thicker than the thickness of the film itself. On the other end, they remain physically and optically attached and aligned to the larger film lightguide. The film cutting is achieved by stamping, laser-cutting, mechanical cutting, water-jet cutting, local melting or other film processing methods. Preferably die cut results in an optically smooth surface to promote total internal reflection of the light to improve light guiding through the length of the snips. A light source is coupled to the bundled strips. The ships are arranged so that light propagates through them via total internal reflection and is transferred into the film lightguide portion. The bundled strips form a light input edge having a thickness much greater than the film lightguide region. The light input edge of the bundled ships defines a light input surface to facilitate more efficient transfer of light from die light source into die lightguide, as compared to conventional methods that couple to the edge or top of the film. The ships can be melted or mechanically forced together at the input to improve coupling efficiency. If the bundle is square shaped, the length of one of its sides I, is given by I~V(w x t) where w is the total width of the lightguide input edge and t is the thickness of the film. For example, a 0.1mm thick film with lm edge would give a square input bundle with dimensions of 1cm x 1 cm. Considering these dimensions, the bundle is much easier to couple light into compared to coupling along the length of die film when using typical light sources (e.g. incandescent, fluorescent: metal halide, xenon and LED sources). The improvement in coupling efficiency and cost is particularly pronounced at film thicknesses below 0.25mm. because that thickness is approximately the size of many LED and laser diode chips. Therefore, it would be difficult and or expensive to manufacture micro-optics to efficiently couple light into the film edge from an LED chip because of the etendue and manivfacturing tolerance limitations. Also, it should be noted that the folds in the slots are not creases but rather have some radius of curvature to allow effective light transfer. Typically the fold radius of curvature will be at least ten times the thickuess of the film.

[126] An example of one embodiment that has been brought to practice is described here. The apparanis began with a 381 micron thick polycarbonate film which was 457 nun wide and 762 mm long. The 457 mm edge of the film is cut into 6.35 mm wide strips using an array of razor blades. These snips are grouped into three 152.4 mm wide sets of snips, which are further split into two equal sets that were folded towards each other and stacked separately into 4.19 mm by 6.35 mm stacks. Each of the three pairs of stacks was then combined together in the center in the method to create a combined and singular input stack of 8.38 mm by 6.35 mm size. An LED module, MCE LED module from Cree Inc.. is coupled into each of the three input stacks. Light emitted from the LED enters the film stack with an even input, and a portion of tins light remains within each of the 15 mil strips via total internal reflections while propagating through the strip. The light continues to propagate down each strip as they break apart in their separate configurations, before entering the larger lightguide. Fimhermoie. a finned aluminum heat sink was placed down the length of each of the. three coupling apparatuses to dissipate heat from the LED. This assembly shows a compact design that can be aligned in a linear array, to create uniform light. Light traveling within the film exits in a light emitting region representing indicia due to light extraction from individual light extt"action features that collectively arrange to form a light emitting indicia, graphic, icon, or image.

[127] A method to manufacture one embodiment of a backlight comprising three film-based lightguides is as follows. Three layers of thin film lightguides (<250 microns) are laminated to each other with a layer of lower refractive index material between them (e.g. methyl-based silicone PSA). Then, an angled beam of light, ions or mechanical substance (i.e. particles and/or fluid) patterns lines or spots into the film. If necessary, a photosensitive material should be layered on each material beforeliand. The angle of the beam is such that the extraction features on the layers have the proper offset. The angle of the beam is dictated by the lightguide thickness and the width of the pixels and is given by 9=tan ^" '(t w). where Θ is the relative angle of light to the plane of the lightguide, t is the lightguide and cladding thickness and w is the width of the pixels. Ideally the extraction fearares direct the light primarily in a direction toward the intended pixel to rninimize cross-talk.

[128] Exemplary embodiments of light emitting devices and methods for making or producing the same are described above in detail. The devices, components, and methods are not limited to die specific embodiments described herein, but rather, the devices, components of the devices and/or steps of the methods may be utihzed independently and separately from other devices, components and/or steps described herein. iFiuther, the described devices, components and/or the described methods steps can also be defined in, or used in combination with, other devices and/or methods, and are not limited to practice with only the devices and methods as described herein.

EQUIVALENTS

[129J Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of the invention. Various substitutions, alterations, and modifications may be made to the invention without departing from the spirit and scope of the invention. Other aspects, advantages, and modifications are within the scope of the invention. This application is intended to cover any adaptations or vaiiations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

[130] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be imderstood as being modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. Unless indicated to the contrary, all tests and properties are measured at an ambient temperature of 25 degrees Celsius or the environmental temperanire within or uear the device when powered on (when indicated) under constant ambient room temperanire of 25 degrees Celsius. As used throughout the specification, the term "one or more of the following" is intended to indicate that one or more of the listed items, components, or fimctions, for example, can be selected, and the selection may include one or more of each of the selected items, components, or fimctions. for example.