LIGHTING ASSEMBLY INCLUDING SAME

RELATED APPLICATION DATA

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62/360,743, filed July 11, 2016, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] Energy efficiency has become an area of interest for energy consuming devices. One class of energy consuming devices is lighting devices. Light emitting diodes (LEDs) show promise as energy efficient light sources for lighting devices. One example in which such lighting devices may be utilized is ceiling and wall fixtures. Such lighting devices can provide a fixture with a relatively thin profile, but light guides used in these devices provide very little in terms of differentiation.

SUMMARY

[0003] In accordance with one aspect of the present disclosure, a light guide includes: a first major surface; a second major surface opposed the first major surface; a light input edge, the first major surface and the second major surface configured to propagate light input to the light guide through the light input edge by total internal reflection; light extracting elements at at least one of the major surfaces; a first light output region at the first major surface, a first portion of the light extracting elements associated with the first light output region, the first portion of the light extracting elements arranged to extract light from the first light output region at a given intensity and arranged such that the light output intensity profile of the first light output region is nominally uniform; and a second light output region at the first major surface, a second portion of the light extracting elements associated with the second light output region, the second portion of the light extracting elements arranged to extract light from the second light output region at an intensity less than the intensity of the first light output region and arranged such that at least a portion of a light output intensity profile of the second light output region decreases with increasing distance from the first output region toward an edge of the light guide. [0004] In some embodiments, the first major surface is planar and the second major surface is planar.

[0005] In some embodiments, the first light output region is in contact with the second light output region.

[0006] In some embodiments, the first light output region is separated from the second light output region by a separation region having no light extracting elements.

[0007] In some embodiments, the first light output region is centrally located at the first major surface of the light guide.

[0008] In some embodiments, the first light output region is rectangular in shape. The second light output region may be trapezoidal in shape.

[0009] In some embodiments, the first light output region is circular in shape. The second light output region may surround the first light output region.

[0010] In some embodiments, the first light output region is ring-shaped. The light guide may further include a third light output region at the first major surface located within the ring-shaped first light output region, a third portion of the light extracting elements associated with the third light output region, the third portion of the light extracting elements arranged to extract light from the third light output region at an intensity less than the intensity of the first light output region.

[0011] In some embodiments, the light guide further includes a third light output region at the first major surface, a third portion of the light extracting elements associated with the third light output region, the third portion of the light extracting elements arranged to extract light from the third light output region at an intensity less than the intensity of the first light output region and arranged such that a light output intensity profile of the third light output region decreases monotonically with increasing distance from the first output region toward an edge of the light guide. The second light output region may be separated from the third light output region by a separation region having no light extracting elements associated therewith.

[0012] In some embodiments, the second light output region radially extends from the first light output region. [0013] In some embodiments, the light extracting elements associated with the first light output region are light scattering elements and the light extracting elements associated with the second light output region are light extracting elements of well-defined shape.

[0014] In some embodiments, a light output intensity profile of the second light output region decreases monotonically with increasing distance from the first output region to an edge of the light guide.

[0015] In some embodiments, the light output intensity profile of the first light output region has a light output intensity uniformity of 85% or more.

[0016] In some embodiments, a lighting assembly includes the light guide and a light source adjacent the light input edge.

[0017] In accordance with another aspect of the present disclosure, a lighting assembly includes a light guide includes: a first major surface; a second major surface opposed the first major surface; a light input edge, the first major surface and the second major surface configured to propagate light input to the light guide through the light input edge by total internal reflection; light extracting elements at at least one of the major surfaces; a first light output region at the first major surface, a first portion of the light extracting elements associated with the first light output region, the first portion of the light extracting elements arranged to extract light from the first light output region at a given intensity; a second light output region at the first major surface, a second portion of the light extracting elements associated with the second light output region, the second portion of the light extracting elements arranged to extract light from the second light output region at an intensity less than the intensity of the first light output region; and a separation region having no light extracting elements associated therewith separating the first light output region and the second light output region.

[0018] In some embodiments, the first major surface is planar and the second major surface is planar.

[0019] In some embodiments, the first light output region is centrally located at the first major surface of the light guide.

[0020] In some embodiments, the first light output region is rectangular in shape. [0021] In some embodiments, the first light output region is circular in shape.

[0022] In some embodiments, a light output intensity profile of the second light output region decreases monotonically with increasing distance from the first output region to an edge of the light guide.

[0023] In some embodiments, a lighting assembly includes the light guide and a light source adjacent the light input edge.

[0024] In accordance with another aspect of the present disclosure, a lighting assembly includes a first major surface; a second major surface opposed the first major surface; a light input edge, the first major surface and the second major surface configured to propagate light input to the light guide through the light input edge by total internal reflection; first light extracting means for extracting light from a first light output region at the first major surface at a given intensity and with a nominally uniform light output intensity profile; and second light extracting means for extracting light from a second light output region at the first major surface at an intensity less than the intensity of the first light output region and with a light output intensity profile, at least a portion of which decreases with increasing distance from the first output region toward an edge of the light guide.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIGS. 1-3 are schematic perspective views of parts of exemplary lighting assemblies.

[0026] FIGS. 4 and 5 are schematic views of parts of exemplary light guides showing exemplary light extracting elements.

[0027] FIG. 6 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith.

[0028] FIG. 6A is an exemplary field of illumination of the light guide of FIG. 6. [0029] FIG. 7 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith.

[0030] FIG. 7 A is an exemplary field of illumination of the light guide of FIG. 7.

[0031] FIG. 8 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith.

[0032] FIG. 8A is an exemplary field of illumination of the light guide of FIG. 8.

[0033] FIG. 9 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith.

[0034] FIG. 9A is an exemplary field of illumination of the light guide of FIG. 9.

[0035] FIG. 10 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith.

[0036] FIG. 10A is an exemplary field of illumination of the light guide of FIG. 10.

[0037] FIG. 11 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith.

[0038] FIG. 11A is an exemplary field of illumination of the light guide of FIG. 11.

[0039] FIGS. 12 and 13 are schematic top views of parts of exemplary lighting assemblies including a light guide having light output regions with light extracting elements respectively associated therewith.

[0040] FIG. 14 is a schematic perspective view of parts of an exemplary lighting assembly.

[0041] FIG. 15 is a schematic side view of parts of an exemplary lighting assembly. [0042] FIG. 16 is a schematic top view of an exemplary cover element.

DESCRIPTION

[0043] Embodiments will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. The figures are not necessarily to scale. Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other

embodiments. In this disclosure, angles of incidence, reflection, and refraction and output angles are measured relative to the normal to the surface (e.g., the major surface).

[0044] In various embodiments described in the present disclosure, lighting assemblies including light guides (e.g., planar light guides) have arrangements of light output regions and light extracting elements respectively associated therewith, which can provide an edge lit light fixture appearing to have depth / curvature at the major surface when the light guide is edge lit. Although the major surface of the light guide may be planar, the arrangement of the light output regions and the patterning of light extracting elements associated therewith may make the surface of the light guide appear three-dimensional. Even in embodiments where the light guide is curved, the arrangement of the light output regions and the patterning of light extracting elements associated therewith may increase the three-dimensional appearance of the light guide at the major surface.

[0045] With initial reference to FIG. 1, an exemplary embodiment of a lighting assembly is shown at 100. The lighting assembly 100 includes a light guide 102. The light guide 102 is a solid article of manufacture (e.g., a substrate) made from, for example, polycarbonate, poly(methyl-methacrylate) (PMMA), glass, or other appropriate material. The light guide 102 may also be a multi -layer light guide having two or more layers that may differ in refractive index. The light guide 102 includes a first major surface 106 and a second major surface 108 opposite the first major surface 106. The light guide 102 is configured to propagate light by total internal reflection between the first major surface 106 and the second major surface 108. The length and width dimensions of each of the major surfaces 106, 108 are greater, typically ten or more times greater, than the thickness of the light guide 102. The thickness is the dimension of the light guide 102 in a direction orthogonal to the major surfaces 106, 108. The thickness of the light guide 102 may be, for example, about 0.1 millimeters (mm) to about 10 mm.

[0046] At least one edge surface extends between the major surfaces 106, 108 of the light guide in the thickness direction. The total number of edge surfaces depends on the configuration of the light guide. In the case where the light guide is rectangular (e.g., as exemplified in FIG. 1), the light guide has four edge surfaces 110, 112, 114, 116. In the embodiment shown, the light guide extends in a first direction 115 (e.g., a length direction) between edge surface 110 and edge surface 112; and extends in a second direction 117 (e.g., a width direction) orthogonal to the first direction 115 between edge surface 114 and edge surface 116. Other light guide shapes result in a corresponding number of side edges. Although not shown, in some embodiments, the light guide 102 may additionally include one or more edge surfaces defined by the perimeter of an orifice extending through the light guide in the thickness direction. Each edge surface defined by the perimeter of an orifice extending through the light guide 102 will hereinafter be referred to as an internal edge surface. Depending on the shape of the light guide 102, each edge surface may be straight or curved, and adjacent edge surfaces may meet at a vertex or join in a curve. Moreover, each edge surface may include one or more straight portions connected to one or more curved portions. The edge surface through which light from the light source 104 is input to the light guide will now be referred to as a light input edge. In the embodiment shown in FIG. 1, the edge surface 110 is a light input edge. In some embodiments, the light guide 102 includes more than one light input edge. For example, FIG. 2 shows an exemplary embodiment of the lighting assembly in which a light source 104 is also present at the edge surface 112 opposite the edge surface 110. In another example, a light source may also be present at the edge surface 114 and/or the edge surface 116. Furthermore, the one or more light input edges may be straight and/or curved.

[0047] In the embodiment shown in FIG. 1, the major surfaces 106, 108 are planar. In other embodiments, at least a portion of the major surfaces 106, 108 of the light guide 102 is curved in one or more directions. In one example, the intersection of the edge surface 110 and one of the major surfaces 106, 108 defines a first axis, and at least a portion of the light guide 102 curves about an axis parallel to the first axis. In another example, at least a portion of the light guide 102 curves about an axis orthogonal to the first axis. [0048] With continued reference to FIG. 1, the lighting assembly 100 includes a light source 104 positioned adjacent the light input edge 110. The light source 104 is configured to edge light the light guide 102 such that light from the light source 104 enters the light input edge 110 and propagates along the light guide 102 by total internal reflection at the major surfaces 106, 108. In embodiments where the light guide includes more than one light input edge, (e.g., such as the embodiment shown in FIG. 2 in which edge surface 110 and edge surface 112 are both light input edges), the lighting assembly may include more than one light source (e.g., such as in the exemplary embodiment shown in FIG. 2).

[0049] The light source 104 may include one or more solid-state light emitters 118. The solid-state light emitters 118 constituting the light source 104 are arranged linearly or in another suitable pattern depending on the shape of the light input edge of the light guide 102 to which the light source 104 supplies light. Exemplary solid-state light emitters 118 include such devices as LEDs, laser diodes, and organic LEDs (OLEDs). In an embodiment where the solid-state light emitters 118 are LEDs, the LEDs may be top-fire LEDs or side-fire LEDs, and may be broad spectrum LEDs (e.g., white light emitters) or LEDs that emit light of a desired color or spectrum (e.g., red light, green light, blue light, or ultraviolet light), or a mixture of broad-spectrum LEDs and LEDs that emit narrowband light of a desired color. In one embodiment, the solid-state light emitters 118 emit light with no operably-effective intensity at wavelengths greater than 500 nanometers (nm) (i.e., the solid-state light emitters 118 emit light at wavelengths that are

predominantly less than 500 nm). In some embodiments, the solid-state light emitters 118 constituting light source 104 all generate light having the same nominal spectrum. The term "nominally" as used in the present disclosure encompasses variations of one or more parameters that fall within acceptable tolerances in design and/or manufacture. In other embodiments, at least some of the solid-state light emitters 118 constituting light source 104 generate light that differs in spectrum from the light generated by the remaining solid- state light emitters 118.

[0050] The lighting assembly 100 may include one or more additional components. For example, although not specifically shown in detail, in some embodiments of the lighting assembly, the light source 104 includes structural components to retain the solid-state light emitters 118. In the example shown in FIG. 1, the solid-state light emitters 118 may be mounted to one or more printed circuit boards (PCB) 120. In other embodiments, the solid-state light emitters 118 may be mounted to a substrate such as a flexible and/or conformable substrate (FIG. 11, element 121). The light source 104 may additionally include circuitry, power supply, electronics for controlling and driving the solid-state light emitters 118, and/or any other appropriate components.

[0051] With additional reference to FIG. 3, the lighting assembly 100 may include a housing 122 for retaining the light source 104 and the light guide 102. The housing 122 may retain a heat sink or may itself function as a heat sink. In some embodiments, the lighting assembly 100 includes a mounting mechanism to mount the lighting assembly to a retaining structure (e.g., a ceiling, a wall, etc.). For example, the housing of the lighting assembly may be configured to mount directly to a ceiling and/or may be configured to be integrated as part of a dropped/suspended ceiling (e.g., as a dropped ceiling tile). In other embodiments, the housing of the lighting assembly may be configured to mount directly to or to be integrated with a wall.

[0052] The lighting assembly 100 may include a reflector (not shown) adjacent one of the major surfaces 106, 108. The reflector may be a specular reflector, a diffuse reflector, or a patterned reflector. The light extracted through the major surface adjacent the reflector may be reflected by the reflector, re-enter the light guide 102 at the major surface, and be output from the light guide 102 through the other major surface.

[0053] With continued reference to FIGS. 1 and 2, the light guide 102 includes light extracting elements 124 in, on, or beneath at least one of the major surfaces 106, 108. Light extracting elements that are in, on, or beneath a major surface will be referred to as being "at" the major surface. In FIGS. 1 and 2, the light extracting elements 124 are shown as being at the first major surface 106. While the light extracting elements 124 are shown in FIG. 1 as truncated cones (e.g., frustoconical-shaped micro-optical elements), it will be understood that the light extracting elements can respectively have one or more specific configurations, such as those described below. The reference numeral 124 will be generally used to collectively refer to the different embodiments of light extracting elements.

[0054] Each light extracting element 124 functions to disrupt the total internal reflection of the light propagating in the light guide and incident thereon. In one embodiment, the light extracting elements 124 reflect light toward the opposing major surface so that the light exits the light guide 102 through the opposing major surface. Alternatively, the light extracting elements 124 transmit light through the light extracting elements 124 and out of the major surface of the light guide 102 having the light extracting elements 124. In another embodiment, both types of light extracting elements 124 are present. In yet another embodiment, the light extracting elements 124 reflect some of the light and refract the remainder of the light incident thereon, and therefore the light extracting elements 124 are configured to extract light from the light guide 102 through one or both of the major surfaces 106, 108.

[0055] Exemplary light extracting elements 124 include light-scattering elements, which are typically features of indistinct shape or surface texture, such as printed features, ink-jet printed features, selectively-deposited features, chemically etched features, laser etched features, and so forth. FIG. 4 shows an exemplary embodiment of light extracting elements 124 embodied as light-scattering elements. The light-scattering elements are shown as depressions in the major surface having a surface 125 of indistinct shape that may extract the light propagating in the light guide in a diffuse manner. In other embodiments, the light-scattering elements are protrusions at the major surface. In an example, the light-scattering elements shown in FIG. 4 may be formed by laser etching (e.g., directly on the major surface of the light guide, or on a shim or master that is subsequently used to form the light guide).

[0056] Other exemplary light extracting elements 124 include features of well-defined shape, such as grooves (e.g., V-grooves and/or truncated V-grooves) that are recessed into or protrude from the major surface. Other exemplary light extracting elements 124 include micro-optical elements, which are features of well-defined shape that are small relative to the linear dimensions of the major surfaces 106, 108. The smaller of the length and width of a micro-optical element is less than one-tenth of the longer of the length and width (or circumference) of the light guide 102 and the larger of the length and width of the micro-optical element is less than one-half of the smaller of the length and width (or circumference) of the light guide 102. The length and width of the micro-optical element is measured in a plane parallel to the major surface 106, 108 of the light guide 102 for planar light guides or along a surface contour for non-planar light guides 102. [0057] Light extracting elements 124 of well-defined shape (e.g., the above-described grooves and micro-optical elements) are shaped to predictably reflect and/or refract the light propagating in the light guide 102. In some embodiments, at least one of the light extracting elements 124 is an indentation (depression) of well-defined shape in the major surface 106, 108. In other embodiments, at least one of the light extracting elements 124 is a protrusion of well-defined shape from the major surface 106, 108. The light extracting elements of well-defined shape have distinct surfaces on a scale larger than the surface roughness of the major surfaces 106, 108. Light extracting elements of well- defined shape exclude features of indistinct shape or surface textures, such as printed features of indistinct shape, ink-jet printed features of indistinct shape, selectively- deposited features of indistinct shape, and features of indistinct shape wholly formed by chemical etching or laser etching. Each light extracting element 124 of well defined shape includes at least one surface configured to refract and/or reflect light propagating in the light guide 102 and incident thereon such that the light is extracted from the light guide. Such surface(s) is also herein referred to as a light-redirecting surface.

[0058] Exemplary micro-optical element shapes include cones, truncated cones, pyramids, truncated pyramids, and football shapes. FIGS. 1 and 2 show an exemplary embodiment of a light extracting element 124 embodied as a frustoconical-shaped micro- optical element at a major surface of the light guide 102. The frustoconical-shaped micro- optical element 124 includes a side surface 126 and an end surface 128. The

frustoconical-shaped micro-optical element may be a depression or protrusion at the major surface.

[0059] FIG. 5 shows an exemplary embodiment of a light extracting element 124 embodied as a football -shaped micro-optical element at a major surface of a light guide 102, which is configured as v-groove-shaped depression having an arcuate ridge. This football-shaped micro-optical element may alternatively be configured as a v-groove- shaped protrusion with an arcuate ridge. The football-shaped micro-optical element 124 includes a first side surface 130 and a second side surface 132 that come together to form a ridge 134 having ends that intersect the major surface at which the micro-optical element 124 is formed. Other exemplary light extracting elements 124 may have other suitable shapes. Exemplary micro-optical elements are described in U.S. Patent No. 6,752,505, the entire content of which is incorporated by reference, and, for the sake of brevity, are not described in detail in this disclosure.

[0060] The light extracting elements 124 are configured to extract light in a defined intensity profile (e.g., a uniform intensity profile) and with a defined light ray angle distribution from one or both of the major surfaces 106, 108. In this disclosure, intensity profile refers to the variation of intensity with regard to position within a light-emitting region (such as the major surface or a light output region of the major surface). The intensity profile of a light-emitting region may also be referred to as a field of

illumination. The term light ray angle distribution is used to describe the variation of the intensity of light with ray angle (typically a solid angle) over a defined range of light ray angles. In an example in which the light is emitted from an edge-lit light guide, the light ray angles can range from -90° to +90° relative to the normal to the major surface.

[0061] As described above, the edge lit light guide can be used as part of a lighting assembly for one of several general lighting implementations such as ceiling fixtures and wall fixtures. Use of the edge lit light guide provide an option for the lighting fixtures to be provided with a relatively thin profile. As an example, a standard 2' x 2' ceiling fixtures can be made under 0.5" (e.g., less than 15 mm) in total fixture thickness. This can provide a significant advantage over conventional lighting fixtures that use fluorescent and/or incandescent bulbs, as space above a ceiling or behind a wall can be limited.

[0062] In the exemplary embodiments shown in FIGS. 1-3, the major surfaces 106, 108 of the light guide may be nominally planar, which may allow for the thin profile of the lighting assembly. The lighting assembly may be configured to provide a uniform visual appearance over the area of the fixture, which may work well functionally, but provides little in terms of differentiation.

[0063] In various embodiments in the present disclosure, lighting assemblies including light guides (e.g., planar light guides) have arrangements of light output regions and light extracting elements respectively associated therewith, which can provide an edge lit light fixture appearing to have depth / curvature at the major surface when the light guide is edge lit. Although the major surface of the light guide may be planar, the arrangement of the light output regions and the patterning of light extracting elements associated therewith may make the surface of the light guide appear three-dimensional. For example, in some embodiments, the light guide may appear to have depth into or out of the fixture when an observer views the light guide when the light guide is edge lit. Even in embodiments where the light guide is curved, the arrangement of the light output regions and the patterning of light extracting elements associated therewith may increase the three- dimensional appearance of the light guide at the major surface.

[0064] The three-dimensional appearance may be achieved by providing an arrangement of light output regions having respective shapes and patterning of light extracting elements respectively associated with the light output regions, and may be designed to collectively provide the appearance of depth / curvature at the major surface when the light guide is edge lit. In some embodiments, at least one of the light output regions may have a different light output intensity as compared with the other light output regions.

Furthermore, in some embodiments, the light extracting elements associated with at least one of the light output regions may be varied in density and/or type to achieve a change / reduction / fade in the light output intensity over at least a portion of the light output region. In some embodiments, the three-dimensional appearance may also be achieved by including one or more separation regions that separate adjacent light output regions. The one or more separation regions may have no light output elements associated therewith and/or the separation regions may be configured as masks that block light from being extracted from the light guide. A separation region may separate two or more of the respective light output regions and may be shaped to give the appearance of structure to the fixture.

[0065] FIGS. 6-13 show exemplary embodiments of lighting assemblies including a light guide having light output regions with light extracting elements respectively associated therewith. The light output regions are shown as outlined regions with light extracting elements dispersed therein. The light extracting elements shown in FIGS. 6-13 are schematically provided to exemplify the relative density of the light extracting elements among the respective regions (and in some embodiments, the change in density in the respective regions), which may provide the difference and/or variation in light output intensity of the respective regions. It will be understood, however, that the particular arrangement of the light extracting elements shown in the figures is not intended to be limiting, as the light extracting elements respectively associated with the light output regions may be provided in in any suitable amount and arrangement to yield the particular shape of the light output region having the desired light output intensity and desired light output intensity profile. It will also be understood that while the lighting assemblies shown in FIGS. 6-13 include a light source adjacent one of the edge surfaces (e.g., similar to the embodiment shown in FIG. 1), in other embodiments the lighting assembly may include more than one light source, and the light sources may be arranged adjacent respective edge surfaces of the light guide (e.g., such as an arrangement similar to that shown in FIG. 2, or in another suitable arrangement).

[0066] While the light extracting elements are schematically shown in FIGS. 6-13 as dots, it will be understood that the light extracting elements may be provided as one or more suitable shapes such as those described above. For example, the light extracting elements may be light-scattering elements (e.g., laser-etched features). In another example, the light extracting elements may be features of well-defined shape (e.g., the frustoconical-shaped elements shown in FIG. 1 or the football-shaped elements shown in FIG. 5). The light extracting elements of the light guide may be provided as the same type of light extracting elements or as a mixture of two or more light extracting elements. In an example, all the light extracting elements in the respective light output regions of the light guide may be the same type of light extracting element. In another example, there may be multiple types of light extracting elements provided in a given light output region. In another example, the light extracting elements in one of the light output regions may be one type of light extracting element, while the light extracting elements in one or more of the other light output regions may be another type of light extracting element.

[0067] FIG. 6 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith. The light guide 102 includes light output regions 600, 602, 604, 606, 608; and may also include separation regions 650, 652, 654, 656. This arrangement may provide the appearance that the rectangular center is recessed into the fixture (e.g., in a troffer) when the light guide is edge lit. This recessed region may appear to be connected to the end edges of the light guide by angled surfaces (the trapezoid shaped regions as described below).

[0068] The light output regions shown in FIG. 6 include a rectangular-shaped (e.g., square) region 600, as well as four trapezoid- shaped regions 602, 604, 606, 608 that each extend from a respective edge of the light guide toward the rectangular-shaped region. In the embodiment shown, the rectangular-shaped region 600 is proximate the center of the major surface 106 of the light guide 102. Abutting trapezoid-shaped regions are respectively separated by a separation region 650, 652, 654, 656. In some embodiments, the separation regions 650, 652, 654, 656 have no light extracting elements associated therewith. The separation regions 650, 652, 654, 656 are schematically shown as blacked- out regions in FIG. 6, although it will be appreciated that these regions may not actually be shaded as such. Hence, the regions having no light output elements 650, 652, 654, 656 may not be easily differentiated from the light output regions when the lighting assembly is in the off state (e.g., when the light guide is not being edge lit by the light source). In other embodiments, the separation regions 650, 652, 654, 656 may be provided as opaque regions (e.g., defined by a mask provided at the major surface).

[0069] The separation regions 650, 652, 654, 656 are shaped to provide the appearance of structure and/or depth to the flat light guide, which helps to provide the appearance of three-dimensional structure when the light guide is edge lit. In the example shown in FIG. 6, these separation regions 650, 652, 654, 656 are shown as extending from the

rectangular- shaped region 600 to the outer edge of the light guide (e.g., to the intersection of two respective edge surfaces of the light guide). At least a portion of each of these separation regions may increase in width as it extends from the rectangular center region to the outer edge. As an example, each of these separation regions 650, 652, 654, 656 may increase monotonically in width as it extends from the rectangular center region to the outer edge. In some embodiments, the width of the separation regions may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm).

[0070] In some embodiments, the rectangular-shaped region 600 touches the respective trapezoid-shaped regions 602, 604, 606, 608. In such embodiments, the rectangular border 658 between the rectangular-shaped region 600 and the trapezoid-shaped regions 602, 604, 606, 608 is shown in FIG. 6 simply to show demarcation between the rectangular- shaped region and the trapezoid-shaped regions. In other embodiments, the border 658 between the rectangular-shaped region and the trapezoid-shaped regions is also a separation region, and the region 658 may provide the appearance of further structure in the fixture. In some embodiments, the width of the separation regions 658 may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm). [0071] Light extracting elements 124 associated with the respective light output regions 600, 602, 604, 606, 608 may be arranged to provide a field of illumination to the light guide that gives a three-dimensional appearance. As schematically shown in FIG. 6, the portion of the light extracting elements associated with the rectangular-shaped region 600 may be arranged such that they are provided in the densest population as compared with the density light extracting elements associated with the other light output regions. The rectangular- shaped region 600 may therefore be configured such that it is the highest intensity (brightest) region of the light guide when the light guide is edge lit. As an example, the rectangular-shaped region 600 may appear to be the source of light in the fixture. The density of the light extracting elements associated with the rectangular- shaped region may be nominally constant throughout the region and the rectangular- shaped region may therefore provide a nominally uniform light output intensity profile. Although, in other embodiments, the density light extracting elements associated with the rectangular- shaped region may be arranged such that the density and light output intensity profile may vary within the rectangular region 600.

[0072] As described above, the term "nominally" as used in the present disclosure encompasses variations of one or more parameters that fall within acceptable tolerances in design and/or manufacture. As an example, a nominally uniform light output intensity profile of a given light output region may provide a light output intensity uniformity of 80% or more throughout the region. As another example, a nominally uniform light output intensity profile of a given light output region may provide a light output intensity uniformity of 85% or more throughout the region. As another example, a nominally uniform light output intensity profile of a given light output region may provide a light output intensity uniformity of 90% or more throughout the region.

[0073] As further shown in FIG. 6, respective portions of the light extracting elements are associated with the trapezoid-shaped regions 602, 604, 606, 608. The light extracting elements 124 associated with the trapezoid-shaped regions 602, 604, 606, 608 may be patterned such that the density of the light extracting elements decreases over at least a portion of the region. In an example, the density of the light extracting elements decreases (e.g., monotonically) as a function of distance from the rectangular-shaped region 600. This patterning of the light extracting elements may provide a fade in light output as a function of distance from the rectangular-shaped region 600 to the edges of the light guide, thereby giving the appearance that the center is recessed (e.g., by a distance of several inches) into the fixture. At least a portion of the light output intensity profile in the respective trapezoid-shaped regions may decrease with increasing distance from the rectangular- shaped region toward an edge of the light guide. In an example, the light output intensity profile in the respective trapezoid-shaped regions may decrease (e.g., monotonically) with increasing distance from the rectangular- shaped region. Although, in other embodiments, the respective densities of the light extracting elements associated with the trapezoid-shaped regions 602, 604, 606, 608 may be nominally constant (and may provide a nominally uniform light output intensity profile). In such embodiments, the density of the light extracting elements associated with the the trapezoid-shaped regions 602, 604, 606, 608 may be less than the density of the light extracting elements in the rectangular- shaped region 600, such that the rectangular-shaped region may be the most intense (brightest) region of the light guide when the light guide is edge lit. The separation regions 650, 652, 654, 656 may provide the appearance of structure and/or depth to the light guide.

[0074] In some embodiments, the light extracting elements associated with the light output regions may be the same type of light extracting element. For example, each of the light output regions 600, 602, 604, 606, 608 may include light-scattering elements. In other embodiments, the light extracting elements associated with one of the light output regions may be one type of light extracting element, while the light extracting elements associated with one or more of the other light output regions may be another type of light extracting element. In an example, the rectangular-shaped region 600 may include light extracting elements that output light in a diffuse manner (e.g., laser-etched features), while one or more of the trapezoid-shaped regions may include light extracting elements have a defined directional output (e.g., the frustoconical-shaped elements shown in FIG. 1 or the football-shaped elements shown in FIG. 5). The directional output from the trapezoid- shaped regions may further enhance the three-dimensional appearance of the light guide when it is edge lit, as different regions may appear darker or brighter depending on the angle at which the light guide is viewed.

[0075] FIG. 6A shows an exemplary field of illumination of the light guide of FIG. 6. As shown, the rectangular-shaped region may appear as the highest intensity (brightest) source of light and may have a nominally uniform light output intensity profile. The trapezoid-shaped regions may appear less intense (dimmer) than the rectangular region and the light output intensity profile of the respective trapezoid-shaped regions may decrease (e.g., monotonically) with increasing distance from the rectangular center region.

[0076] The embodiment shown in FIGS. 6 and 6A is just one exemplary arrangement of a lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith. Other embodiments of the light guide may include other arrangements and patterns, which may also provide a three- dimensional effect at the major surface of the light guide when the light guide is edge lit.

[0077] FIG. 7 is a schematic top view of parts of another exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith. The light guide 102 includes light output regions 700, 702. The light guide 102 may also include a separation region 705. As contrasted with the design shown in FIG. 6, the region provided proximate the center of the major surface of the light guide is circular, and the light output area that surrounds this circular output area is a continuous area (instead of separate trapezoidal areas). This arrangement may provide the appearance that a circular center is recessed and connected to the end edges of the light guide by an angled surface (e.g., in a troffer). This recessed region may appear to be connected to the end edges of the light guide by an angled surface.

[0078] The light output regions shown in FIG. 7 include a circular region 700 proximate the center of the major surface 106 of the light guide 102, as well as a region 702 surrounding the circular region that extends from the edges of the light guide toward the circular region (a surrounding region). In some embodiments, the circular region 700 and the surrounding region 702 may be separated by a separation region 750. The separation region may have no light output elements associated therewith. This separation region 750 is schematically shown as a line that traces around the circumference of the circular region, although it will be appreciated that this region 750 may not actually be shaded as such. Hence, the separation region 750 may not be easily differentiated from the light output regions when the lighting assembly is in the off state (e.g., when the light guide is not being edge lit by the light source). In other embodiments, the separation region 750 may be provided as an opaque region (e.g., defined by a mask provided at the major surface). In some embodiments, the width/thickness of the separation region 750 may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm). The separation region 750 may provide the appearance of structure in the fixture.

[0079] In other embodiments, the circular region 700 touches the surrounding region 702. In such embodiments, the region 750 between the circular region 700 and the surrounding region is shown in FIG. 7 simply to schematically show demarcation between these two regions.

[0080] Light extracting elements 124 may associated with the respective light output regions 700, 702 to provide a field of illumination that gives a three-dimensional appearance to the light guide. As schematically shown in FIG. 7, the portion of the light extracting elements associated with the circular region 700 may be arranged such that they are provided in the densest population as compared with the density light extracting elements associated with the surrounding region 702. The circular region 702 may therefore be configured such that it is the most intense (brightest) region of the light guide when the light guide is edge lit. As an example, the circular region 700 may appear to be the source of light in the fixture. The density of the light extracting elements in the circular region 700 may be nominally constant throughout the region and the circular region may therefore provide a nominally uniform light output intensity profile.

Although, in other embodiments, the density light extracting elements in the circular region may be arranged such that the density and field of illumination may vary throughout the region.

[0081] As further shown in FIG. 7, the portion light extracting elements 124 associated with the surrounding region 702 may be arranged such that the density of the light extracting elements decreases over at least a portion of the region. In an example, the density of the light extracting elements decreases (e.g., monotonically) as a function of distance from the circular region 700. This arrangement of the light extracting elements may provide a fade in light output as a function of distance from the circular region to the edges of the fixture, thereby giving the appearance that the center is recessed (e.g., by a distance of several inches) into the fixture. At least a portion of the light output intensity profile of the surrounding region 702 may decrease with increasing distance from the circular region toward an edge of the light guide. In an example, the light output intensity profile in the surrounding region may decrease (e.g., monotonically) with increasing distance from the circular region 700. Although, in other embodiments, the density of the light extracting elements associated with the surrounding region may be nominally constant (and may provide a nominally uniform light output intensity profile). In such embodiments, the density of the light extracting elements in the surrounding region 702 may be less than the density of the light extracting elements in the circular region 700, such that the circular region 700 may be the most intense (brightest) region of the light guide when the light guide is edge lit. The separation region 750 (when present) may provide the appearance of structure and/or depth to the light guide.

[0082] In some embodiments, the light extracting elements respectively associated with the light output regions may be the same type of light extracting element. For example, each of the regions 700, 702 may include light-scattering elements. In other

embodiments, the light extracting elements associated with one of the light output regions (e.g., the region surrounding the circular region) may be one type of light extracting element, while the light extracting elements associated with the other of the light output regions may be another type of light extracting element. In an exemplary implementation, the circular region may include light extracting elements that output light in a diffuse manner (e.g., laser-etched features), while the region surrounding the circular region may include light extracting elements have a defined directional output (e.g., the frustoconical- shaped elements shown in FIG. 1 or the football-shaped elements shown in FIG. 5). The directional output from the surrounding region 702 may further enhance the three- dimensional appearance of the light guide, as portions of the region surrounding the circular region may appear darker or brighter depending on the angle at which the light guide is viewed.

[0083] FIG. 7 A shows an exemplary field of illumination of the light guide of FIG. 7. As shown, the circular region may appear as the most intense (brightest) source of light and may have a nominally uniform light output intensity profile. The surrounding region may appear less intense (dimmer) than the circular region and the light output intensity profile may decrease (e.g., monotonically) with increasing distance from the circular region.

[0084] FIG. 8 is a schematic top view of parts of another exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith. The light guide 102 includes light output regions 800, 802, 804, and may also include separation regions 850, 852. As contrasted with the design shown in FIG. 7, a ring-shaped region surrounds a circular region that is provided proximate the center of the major surface 106 of the light guide 102. This arrangement of light output regions may give the appearance that a circular center having a ring-shaped light source is recessed and connected to the end edges of the light guide by an angled surface (e.g., in a troffer). This recessed region may appear to be connected to the end edges of the light guide by an angled surface.

[0085] The light output regions shown in FIG. 8 include a circular region 800 proximate the center of the major surface 106 of the light guide 102, a ring-shaped region 802 surrounding the circular region, and a region 804 surrounding the ring-shaped region 802 that extends from the edges of the light guide toward the ring-shaped region (surrounding region). The circular region 800 and the ring-shaped region 802 may be separated by a separation region 850, and the ring-shaped region 802 and the surrounding region 804 may be separated by a separation region 852. The separation regions 850, 852 may have no light output elements associated therewith. These regions 850, 852 are schematically shown as lines that traces around the circumference of the circular region and ring-shaped region, respectively, although it will be appreciated that these regions may not actually be shaded as such. Hence, the regions 850, 852 having no light output elements may not be easily differentiated from the light output regions when the lighting assembly is in the off state (e.g., when the light guide is not being edge lit by the light source). In other embodiments, the separation regions 850, 852 may be provided as opaque regions (e.g., defined by a mask provided at the major surface). In some embodiments, the

width/thickness of the respective separation regions 850, 852 may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm). The regions 850, 852 may provide the appearance of structure in the fixture.

[0086] In other embodiments, the circular region 800 touches the ring-shaped region 802 and/or the ring-shaped region 802 touches the surrounding region 804. In such embodiments, the border between the circular region and the ring-shaped region and/or the border between the ring-shaped region and the surrounding region is shown in FIG. 8 simply to schematically show demarcation between the regions 800, 802, 804.

[0087] Light extracting elements 124 may be associated with the respective light output regions 800, 802, 804 to provide a field of illumination that gives a three-dimensional appearance to the light guide. As schematically shown in FIG. 8, the portion of the light extracting elements associated with the ring-shaped region 802 may be arranged such that they are provided in the densest population as compared with the density of the light extracting elements associated with the other light output regions 800, 804. The ring- shaped region may therefore be configured such that it is the most intense (brightest) region of the light guide when the light guide is edge lit. As an example, the ring-shaped region 802 may appear to be the source of light in the fixture. The density of the light extracting elements associated with the ring-shaped region 802 may be nominally constant throughout the region and the ring-shaped region 802 may therefore provide a nominally uniform light output intensity profile. Although, in other embodiments, the density of the light extracting elements in the ring-shaped region 802 may be arranged such that the density and light output intensity profile may vary within the region.

[0088] As further shown in FIG. 8, the portion of the light extracting elements 124 associated with the circular region 800 may be arranged such that they are provided at a density that is less than the density of the light extracting elements associated with the ring-shaped region 802. The circular region 800 may therefore be configured such that it is the not as bright as the ring-shaped region 802 when the light guide is edge lit. In some embodiments, the density of the light extracting elements associated with the circular region 800 may be nominally constant and the circular region 800 may therefore provide a nominally uniform light output intensity profile. In other embodiments, the density of the light extracting elements in the circular region 800 may be arranged such that the density and light output intensity profile may vary within the region 800 (and may provide a varied light output intensity profile). The separation region 850 (when present) may provide the appearance of structure and/or depth to the light guide.

[0089] As further shown in FIG. 8, the portion of the light extracting elements 124 associated with the surrounding region 804 may be patterned such that the density of the light extracting elements decreases over at least a portion of the region. In an example, the density of the light extracting elements decreases (e.g., monotonically) as a function of distance from the ring-shaped region 802. This patterning of the light extracting elements in the surrounding region 804 may provide a fade in light output as a function of distance from the ring-shaped region 802 to the edges of the light guide, thereby giving the appearance that the center (including the ring-shaped region) is recessed (e.g., by a distance of several inches) into the fixture. At least a portion of the light output intensity profile in the surrounding region 804 may decrease with increasing distance from the ring- shaped region. In an example, the light output intensity profile in the surrounding region may decrease (e.g., monotonically) with increasing distance from the ring-shaped region 802. Although, in other embodiments, the density of the light extracting elements in the surrounding region 804 may be nominally constant (and may provide a nominally uniform light output intensity profile). In such embodiments, the density of the light extracting elements in the surrounding region 804 may be less than the density of the light extracting elements in the ring-shaped region 802, such that the ring-shaped region may be the brightest region of the light guide when the light guide is edge lit. The separation region 852 (when present) may provide the appearance of structure and/or depth to the light guide.

[0090] In some embodiments, the light extracting elements respectively associated with the light output regions may be the same type of light extracting element. For example, each of the regions 800, 802, 804 may include light-scattering elements. In other embodiments, the light extracting elements associated with one of the light output regions (e.g., the region surrounding the ring-shaped region) may be one type of light extracting element, while the light extracting elements associated with one or more of the other of the light output regions may be another type of light extracting element. In an example, the ring-shaped region and circular region may include light extracting elements that output light in a diffuse manner (e.g., laser-etched features), while the region surrounding the circular region may include light extracting elements have a defined directional output (e.g., the frustoconical-shaped elements shown in FIG. 1 or the football-shaped elements shown in FIG. 5). The directional output from the region surrounding the circular region may further enhance the three-dimensional appearance of the light guide, as portions of the region surrounding the circular region may appear darker or brighter depending on the angle at which the light guide is viewed.

[0091] FIG. 8 A shows an exemplary field of illumination of the light guide of FIG. 8. As shown, the ring-shaped region may appear as the most intense (brightest) source of light and may have a nominally uniform light output intensity profile. The circular region and the surrounding region may appear dimmer than the ring-shaped region. The light output intensity profile for the surrounding region may decrease (e.g., monotonically) with increasing distance from the ring-shaped region. [0092] The embodiment of FIG. 8 shows one example of concentric regions, where the ring-shaped region is configured as the brightest region when the light guide is edge lit. In other embodiments, the concentric regions may be configured to have other respective light output intensity profiles. For example, the circular region may instead be configured such that it is the brightest area in the fixture, the ring-shaped region may be configured such that it is less bright than the circular region, and the surrounding region may be configured such that it is less bright than the circular region and the ring-shaped region. The patterning of the light extracting elements associated with each respective region may provide a nominally uniform light output intensity profile, or may fade in output toward the edge of the light guide.

[0093] In other embodiments, the light guide may include more concentric regions than that which is shown in FIG. 8. For example, the light guide may include two or more concentric ring-shaped regions. The two or more concentric ring-shaped regions may be configured as the brightest region when the light guide is edge lit, such that the light guide appears to have multiple ring-shaped light sources.

[0094] In the exemplary embodiments described above, the light output region that may be configured to simulate a light source is provided in the shape of a rectangle (e.g., square), circle, or ring. In other embodiments, the light output regions of the light guide may be configured to simulate a light source having another suitable shape (e.g., hexagon, triangle, oval, etc.).

[0095] For example, FIG. 9 is a schematic top view of parts of an exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith, and includes a hexagon-shaped region. The light guide 102 includes light output regions 900, 902, 904, 906, 908, 910, 912, 914, 916; and may also include separation regions 950, 952, 954, 956, 958, 960, 962, 964, 966. This arrangement of light output regions may give the appearance that the hexagon-shaped region is recessed into the fixture (e.g., in a troffer). This recessed region may appear to be connected to the end edges of the light guide by angled surfaces (the regions 902, 904, 906, 908, 910, 912, 914, 916 as described below).

[0096] The light output regions shown in FIG. 9 include a hexagon-shaped region 900 proximate the center of the major surface 106 of the light guide 102, as well as eight regions 902, 904, 906, 908, 910, 912, 914, 916 that each extend from one or more of the respective edges of the light guide toward the octagon-shaped region 900. These regions 902, 904, 906, 908, 910, 912, 914, 916 are respectively separated by separation regions 950, 952, 954, 956, 958, 960, 962, 964. The separation regions 950, 952, 954, 956, 958, 960, 962, 964 are schematically shown as blacked-out regions in FIG. 9, although it will be appreciated that these regions may not actually be shaded. Hence, the separation regions 950, 952, 954, 956, 958, 960, 962, 964 may not be easily differentiated from the light output regions when the lighting assembly is in the off state (e.g., when the light guide is not being edge lit by the light source). In some embodiments, light extracting elements are not associated with the separation regions 950, 952, 954, 956, 958, 960, 962, 964. In other embodiments, the separation regions 950, 952, 954, 956, 958, 960, 962, 964 may be provided as opaque regions (e.g., defined by a mask provided at the major surface).

[0097] The separation regions 950, 952, 954, 956, 958, 960, 962, 964 are shaped to provide the appearance of structure and/or depth to the flat light guide, which may help to provide the appearance of three-dimensional structure when the light guide is edge lit. In the example shown in FIG. 9, these regions 950, 952, 954, 956, 958, 960, 962, 964 are shown as extending from the octagon-shaped region 900 to the outer edge of the light guide. Each of these regions may increase (e.g., monotonically) in width as it extends from the octagon-shaped region to the outer edge. In some embodiments, the width of the separation regions may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm).

[0098] In some embodiments, the octagon-shaped region 900 touches the respective regions 902, 904, 906, 908, 910, 912, 914, 916. In such embodiments, the octagon-shaped border 968 between the octagon-shaped region 600 and the regions 902, 904, 906, 908, 910, 912, 914, 916 is shown in FIG. 9 simply to show demarcation between the octagon- shaped region and the other light output regions. In other embodiments, the border 968 between the octagon-shaped region and the other light output regions is also a separation region, and the region 968 may provide the appearance of further structure in the fixture. In some embodiments, the width of the separation regions 968 may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm). [0099] Light extracting elements 124 may be associated with the respective light output regions 900, 902, 904, 906, 908, 910, 912, 914, 916 to provide a field of illumination to the light guide that gives the three-dimensional appearance. As schematically shown in FIG. 6, the portion of the light extracting elements associated with the octagon-shaped region 900 may be arranged such that they are provided in the densest population as compared with the density of light extracting elements associated with the other light output regions. The octagon-shaped region 900 may therefore be configured such that it is the most intense (brightest) region of the light guide when the light guide is edge lit. As an example, the octagon-shaped region 900 may appear to be the source of light in the fixture. The density of the light extracting elements associated with the octagon-shaped region 900 may be nominally constant throughout the region and the octagon-shaped region may therefore provide a nominally uniform light output intensity profile.

Although, in other embodiments, the density light extracting elements in the octagon- shaped region may be arranged such that the density and light output intensity profile may vary within the region.

[00100] As further shown in FIG. 9, the respective portions of the light extracting elements 124 associated with the light output regions 902, 904, 906, 908, 910, 912, 914, 916 may be patterned such that the density of the light extracting elements decreases over at least a portion of the region. In an example, the density of the light extracting elements decreases (e.g., monotonically) as a function of distance from the octagon-shaped region 900. This patterning of the light extracting elements may provide a fade in light output as a function of distance from the octagon- shaped region 900 to the edges of the fixture, thereby giving the appearance that the center is recessed (e.g., by a distance of several inches) into the fixture. At least a portion of the light output intensity profile may decrease with increasing distance from the octagon-shaped region. In an example, the light output intensity profile in the respective regions may decrease (e.g., monotonically) with increasing distance from the octagon-shaped region. Although, in other

embodiments, the respective densities of the regions 902, 904, 906, 908, 910, 912, 914, 916 may be nominally constant (and may provide a nominally uniform light output intensity profile). In such embodiments, the density of the light extracting elements associated with the regions 902, 904, 906, 908, 910, 912, 914, 916 may be less than the density of the light extracting elements associated with the rectangular-shaped region, such that the octagon-shaped region may be the brightest region of the light guide when the light guide is edge lit. The regions having no light output elements 950, 952, 954, 956, 958, 960, 962, 964 may provide the appearance of structure and/or depth to the light guide.

[00101] In some embodiments, the light extracting elements associated with the light output regions may be the same type of light extracting element. For example, each of the regions 900, 902, 904, 906, 908, 910, 912, 914, 916 may include light-scattering elements. In other embodiments, the light extracting elements associated with one of the light output regions may be one type of light extracting element, while the light extracting elements associated with one or more of the other light output regions may be another type of light extracting element. In an example, the octagon-shaped region 900 may include light extracting elements that output light in a diffuse manner (e.g., laser-etched features), while one or more of the other regions 902, 904, 906, 908, 910, 912, 914, 916 may include light extracting elements have a defined directional output (e.g., the frustoconical-shaped elements shown in FIG. 1 or the football-shaped elements shown in FIG. 5). The directional output from the other regions 902, 904, 906, 908, 910, 912, 914, 916 may further enhance the three-dimensional appearance of the light guide, as different regions may appear darker or brighter depending on the angle at which the light guide is viewed.

[00102] FIG. 9A shows an exemplary field of illumination of the light guide of FIG. 9. As shown, the octagon-shaped region may appear as the most intense (brightest) source of light and may have a nominally uniform light output intensity profile. The other light output regions may appear less intense (dimmer) than the rectangular region and the light output intensity profile may decrease (e.g., monotonically) with increasing distance from the octagon- shaped region.

[00103] In the exemplary embodiments described above in FIGS. 6-9, the light output region configured to provide the brightest light output is generally centrally located at the major surface of the light guide. In other embodiments, the light output region configured to provide the brightest light output may be offset from the central location. In still other embodiments, more than one light output region may be configured to provide the brightest light output (e.g., to simulate multiple sources of light at the major surface).

[00104] FIG. 10 is a schematic top view of parts of another exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith. The light guide 102 includes light output regions 1000, 1002, 1004, 1006, 1008; and may include separation regions 1050, 1052, 1054, 1056. In the exemplary embodiment of FIG. 10, rectangular regions 1000, 1002 extend between opposed edges 114, 116 of the light guide. This arrangement of light output regions may provide the appearance that one or more light sources (e.g., fluorescent tubes) are recessed in a structure (e.g., in a troffer) that is connected to the end edges of the light guide by an angled surface.

[00105] The light output regions shown in FIG. 10 include rectangular regions 1000, 1002 that extend between opposed edges 114, 116 of the light guide, a rectangular region 1004 disposed between and adjacent regions 1000, 1002, a rectangular region 1006 adjacent the rectangular region 1000, and a rectangular region 1008 adjacent the rectangular region 1002. Adjacent ones of the rectangular regions 1000, 1002, 1004, 1006, 1008 may be respectively separated by a separation region 1050, 1052, 1054, 1056. The separation region 1050, 1052, 1054, 1056 may have no light extracting elements associated therewith. These regions 1050, 1052, 1054, 1056 are schematically shown as lines that respectively separate the regions 1000, 1002, 1004, 1006, 1008, although it will be appreciated that these regions may not actually be shaded as such. Hence, the separation regions 1050, 1052, 1054, 1056 may not be easily differentiated from the light output regions when the lighting assembly is in the off state (e.g., when the light guide is not being edge lit by the light source). In other embodiments, the separation regions 1050, 1052, 1054, 1056 may be provided as opaque regions (e.g., defined by a mask provided at the major surface). In some embodiments, the width of the respective separation regions 1050, 1052, 1054, 1056 may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm). The separation regions 1050, 1052, 1054, 1056 may provide the appearance of structure in the fixture when the light guide is edge lit.

[00106] In other embodiments, two or more of the adjacent rectangular regions 1000, 1002, 1004, 1006, 1008 touch one another. In such embodiments, the regions 1050, 1052, 1054, 1056 between the adjacent ones of the rectangular regions is shown in FIG. 10 simply to schematically show demarcation between the adjacent regions.

[00107] Light extracting elements 124 may be associated with the respective light output regions 1000, 1002, 1004, 1006, 1008 to provide a field of illumination that gives the three-dimensional appearance. As schematically shown in FIG. 9, the portion of the light extracting elements associated with the rectangular regions 1000, 1002 may be arranged such that they are provided in the densest population as compared with the density light extracting elements associated with the other regions. The rectangular regions 1000, 1002 may therefore be configured such that they are the most intense (brightest) regions of the light guide when the light guide is edge lit. As an example, the rectangular regions 1000, 1002 may appear to be the source of light in the fixture. The density of the light extracting elements in the rectangular regions 1000, 1002 may be nominally constant throughout the regions and the rectangular regions 1000, 1002 may therefore provide a nominally uniform light output intensity profile. Although, in other embodiments, the density of the light extracting elements in the rectangular regions 1000, 1002 may be arranged such that the density and light output intensity profile may vary therein.

[00108] As further shown in FIG. 10, the portion of the light extracting elements 124 associated with the rectangular region 1004 may be arranged such that they are provided at a density that is less than the density of the light extracting elements associated with the rectangular regions 1000, 1002. The rectangular region 1004 may therefore be configured such that it is the not as bright as the rectangular regions 1000, 1002 when the light guide is edge lit. In some embodiments, the density of the light extracting elements associated with the rectangular region 1004 may be nominally constant throughout the region and the rectangular region 1004 may therefore provide a nominally uniform light output intensity profile. In other embodiments, the density of the light extracting elements associated with the rectangular region 1004 may be arranged such that the density and light output intensity profile may vary within the region (and may provide a varied light output intensity profile). The regions 1052 and 1054 having no light output elements (when present) may provide the appearance of structure and/or depth to the light guide.

[00109] As further shown in FIG. 10, the portion of the light extracting elements 124 associated with the rectangular region 1006 may be patterned such that the density of the light extracting elements decreases over at least a portion of the region. In an example, the density of the light extracting elements decreases (e.g., monotonically) as a function of distance from the rectangular region 1000. The portion of the light extracting elements 124 associated with the rectangular region 1008 may be patterned such that the density of the light extracting elements decreases over at least a portion of the region. In an example, the density of the light extracting elements decreases (e.g., monotonically) as a function of distance from the rectangular region 1002. This patterning of the light extracting elements in the rectangular regions 1006, 1008 may provide a fade in light output as a function of distance from the rectangular region 1000 to the edge 110 of the light guide, and from the rectangular region 1002 to the edge 112 of the light guide, thereby giving the appearance that the center is recessed (e.g., by a distance of several inches) into the fixture. At least a portion of the light output intensity profile in the rectangular region 1006 may decrease with increasing distance from the rectangular region 1000. In an example, the light output intensity profile in the rectangular region 1006 may decrease (e.g., monotonically) with increasing distance from the rectangular region 1000. At least a portion of the light output intensity profile in the rectangular region 1008 may decrease with increasing distance from the rectangular region 1002. In an example, the light output intensity profile in the rectangular region 1008 may decrease (e.g., monotonically) with increasing distance from the rectangular region 1002. Although, in other embodiments, the density of the light extracting elements in the rectangular regions 1006, 1008 may be nominally constant (and may provide a nominally uniform light output intensity profile). In such embodiments, the density of the light extracting elements associated with the rectangular regions 1006, 1008 may be less than the density of the light extracting elements associated with the rectangular region 1000, 1002 such that the rectangular regions 1000, 1002 may be the most intense (brightest) regions of the light guide when the light guide is edge lit. The regions 1050, 1056 having no light output elements (when present) may provide the appearance of structure and/or depth to the light guide.

[00110] In some embodiments, the light extracting elements associated with the light output regions may be the same type of light extracting element. For example, each of the regions 1000, 1002, 1004, 1006, 1008 may include light-scattering elements. In other embodiments, the light extracting elements associated with one or more of the light output regions may be one type of light extracting element, while the light extracting elements associated with one or more of the other of the light output regions may be another type of light extracting element. In an example, the rectangular regions 1000, 1002, 1004 may include light extracting elements that output light in a diffuse manner (e.g., laser-etched features), while the region surrounding the rectangular regions 1006, 1008 may include light extracting elements have a defined directional output (e.g., the frustoconical-shaped elements shown in FIG. 1 or the football-shaped elements shown in FIG. 5). The directional output from the rectangular regions 1006, 1008 may further enhance the three- dimensional appearance of the light guide, as portions of the region surrounding the circular region may appear darker or brighter depending on the angle at which the light guide is viewed.

[00111] FIG. 10A shows an exemplary field of illumination of the light guide of FIG. 10. As shown, the rectangular regions 1000, 1002 may appear as the most intense (brightest) source of light and may have a nominally uniform field of illumination. The rectangular regions 1004, 1006, 1008 may appear less intense (dimmer) than the ring-shaped region. The light output intensity profile for the rectangular region 1006, 1008 may decrease (e.g., monotonically) with increasing distance from the rectangular regions 1000, 1002, respectively.

[00112] In the exemplary embodiments described above in FIGS. 6-10, the light guide of the lighting assembly is provided as a rectangular (e.g., square). In some examples, the lighting assembly including the rectangular (e.g., square) light guide may be provided to fit a standard 2' x 2' ceiling fixture. In other embodiments, the light guide and lighting assembly may be any other suitable shape.

[00113] FIG. 11 is a schematic top view of parts of another exemplary lighting assembly including a light guide having light output regions with light extracting elements respectively associated therewith. The light guide 102 includes light output regions 1100, 1102; and may also include a separation region 1150. The light guide shown in FIG. 11 is similar to the light guide shown in FIG. 7, but the overall shape of the light guide is circular instead of rectangular. This arrangement of light output regions may give the appearance that a circular center is recessed and connected to the end edges of the light guide by an angled surface (e.g., in a troffer). This recessed region may appear to be connected to the end edges of the light guide by an angled surface. FIG. 1 1 also shows an embodiment in which the light source is mounted on a flexible and/or conformable substrate 121.

[00114] The light output regions shown in FIG. 11 include a circular region 1100 proximate the center of the major surface 106 of the light guide 102, as well as a surrounding region 1102 that surrounds the circular region and extends from the edge of the light guide toward the circular region 1100. The circular region 1100 and the surrounding region 1102 may be separated by a separation region 1150. The separation region may have no light extracting elements associated therewith. This region 1150 is schematically shown as a line that traces around the circumference of the circular region 1100, although it will be appreciated that this region may not actually be shaded. Hence, the region having no light output elements 1150 may not be easily differentiated from the light output regions when the lighting assembly is in the off state (e.g., when the light guide is not being edge lit by the light source). In other embodiments, the separation regions 1150 may be provided as an opaque region (e.g., defined by a mask provided at the major surface). In some embodiments, the width of the respective separation region 1150 may range, for example from about 0.06 inch (e.g., about 1 mm) to about 0.5 inch (e.g., about 12.5 mm). The region 1150 may provide the appearance of structure in the fixture.

[00115] In other embodiments, the circular region 1100 touches the surrounding region 1102. In such embodiments, the region 1150 between the circular region 1100 and the surrounding region 1102 is shown in FIG. 11 simply to schematically show demarcation between the regions.

[00116] Light extracting elements 124 may be associated with the respective light output regions 1100, 1102 to provide a field of illumination that gives a three-dimensional appearance. As schematically shown in FIG. 11, the portion of the light extracting elements associated with the circular region 1100 may be arranged such that they are provided in the densest population as compared with the density of the light extracting elements associated with the surrounding region 1102. The circular region 1100 may therefore be configured such that it is the brightest region of the light guide when the light guide is edge lit. As an example, the circular region 1100 may appear to be the source of light in the fixture. The density of the light extracting elements associated with the circular region 1100 may be nominally constant throughout the region and the circular region 1100 may therefore provide a nominally uniform light output intensity profile. Although, in other embodiments, the density of the light extracting elements associated with the circular region 1100 may be arranged such that the density and light output intensity profile varies within the region.

[00117] As further shown in FIG. 11, the portion of the light extracting elements 124 associated with the surrounding region 1102 may be patterned such that the density of the light extracting elements decreases over at least a portion of the region. In an example, the density of the light extracting elements decreases (e.g., monotonically) as a function of distance from the circular region 1100. This patterning of the light extracting elements may provide a fade in light output as a function of distance from the circular region to the edges of the fixture, thereby giving the appearance that the center is recessed (e.g., by a distance of several inches) into the fixture. At least a portion of the light output intensity profile of the surrounding region 1102 may decrease with increasing distance from the circular region. In an example, the light output intensity profile of the surrounding region may decrease (e.g., monotonically) with increasing distance from the circular region 1100. Although, in other embodiments, the density of the light extracting elements associated with the surrounding region 1102 may be nominally constant (and may provide a nominally uniform light output intensity profile). In such embodiments, the density of the light extracting elements associated with the surrounding region 1102 may be less than the density of the light extracting elements in the circular region 1100, such that the circular region 1100 may be the most intense (brightest) region of the light guide when the light guide is edge lit. The region having no light output elements 1150 (when present) may provide the appearance of structure and/or depth to the light guide.

[00118] In some embodiments, the light extracting elements associated with the light output regions may be the same type of light extracting element. For example, each of the regions 1100, 1102 may include light-scattering elements. In other embodiments, the light extracting elements associated with one of the light output regions (e.g., the region surrounding the circular region) may be one type of light extracting element, while the light extracting elements associated with the other of the light output regions may be another type of light extracting element. In an exemplary implementation, the circular region may include light extracting elements that output light in a diffuse manner (e.g., laser-etched features), while the surrounding region may include light extracting elements having a defined directional output (e.g., the frustoconical-shaped elements shown in FIG. 1 or the football-shaped elements shown in FIG. 5). The directional output from the surrounding region may further enhance the three-dimensional appearance of the light guide, as portions of the surrounding region may appear darker or brighter depending on the angle at which the light guide is viewed.

[00119] FIG. 11 A shows an exemplary field of illumination of the light guide of FIG. 11. As shown, the circular region 1100 may appear as the most intense (brightest) source of light and may have a nominally uniform light output intensity profile. The surrounding region may appear less intense (dimmer) than the circular region and the light output intensity profile may decrease (e.g., monotonically) with increasing distance from the circular region.

[00120] FIGS. 12 and 13 show other exemplary embodiments of lighting assemblies that include other exemplary rectangular-shaped light guides. As shown, the edges 110, 112 of the light guide are longer than the edges 114, 116. The lengths of the edges 110, 112, 114, 116 may be respectively adjusted to suit a desired application. As an example, such light guide shape may be suitable for use in a x 4' or x 8' ceiling fixture ceiling fixture. The light output region arrangement and light extracting element patterning in FIG. 12 is similar to that shown in FIG. 6 and will therefore not be described herein in detail for the sake of brevity. Reference is made to FIGS. 6 and 6A and the accompanying description regarding the respective regions, light extracting element patterning, and light output intensity profile. The light output region arrangement and light extracting element patterning in FIG. 13 is similar to that shown in FIG. 10 and will therefore not be described herein in detail for the sake of brevity. Reference is made to FIGS. 10 and 10A and the accompanying description regarding the respective regions, light extracting element patterning, and light output intensity profile.

[00121] As described above, the arrangement of the light output regions on the major surface of a light guide and the patterning of light extracting elements therein may provide for several different implementations of light guides that when edge lit in a lighting fixture appearing to have depth / curvature at the major surface of the light guide. These several implementations can provide different visual effects. In accordance with some

embodiments, the light guide included in the lighting assembly may be interchangeable with one or more other light guides. This interchangeability allows for a user to change the light guide having one particular arrangement/pattern out with a light guide having another particular arrangement/pattern. In an example, a housing may be included as part of the lighting assembly and may retain the light source and the light guide (e.g., such as the housing 122 shown in FIG. 3). The housing may allow for the light guide to be removed and replaced with a different light guide of similar shape. This may further increase the versatility of the lighting assembly by allowing the light guide(s) to be changed in the field to meet the changing requirements. [00122] In the exemplary embodiments described above, the light extracting elements of the light guide are arranged in light output regions and are patterned to provide an edge lit fixture with the appearance of depth / curvature. In other embodiments, the lighting assembly 200 may include a cover element configured to provide the appearance of depth / curvature. Reference is made to FIGS. 14-16, which show an exemplary embodiment of a lighting assembly 200 including the cover element 202.

[00123] The light guide 102 and light source 104 of the lighting assembly 200 may be similar to the light guide and light source described above with respect to FIGS. 1-5. However, in some embodiments, the light extracting elements of the light guide may be configured to provide a nominally uniform light output over the area of the major surface. The cover element 202 may be adjacent the major surface of the light guide. The cover element 202 is a solid article of manufacture made from, for example, polycarbonate, poly(methyl-methacrylate) (PMMA), glass, or other appropriate material. The cover element 202 may also be a multi-layer light guide having two or more layers that may differ in refractive index. The cover element 202 includes a first major surface 204 and a second major surface 204 opposite the first major surface 204. In the example shown, the second major surface 206 of the cover element 202 is juxtaposed the first major surface 106 of the light guide 102.

[00124] The cover element is configured such that light extracted from the light guide may pass therethrough. The cover element may include light output regions including patterning provided therein at the major surface(s) thereof. While the major surfaces of the cover element and of the light guide may be planar, the output regions and patterning provided by the cover element may make the major surface of the light guide appear three- dimensional. In other embodiments, the light guide may be curved and the cover element may be similarly curved and may conform to the shape of the light guide. Even in such embodiments where the light guide and cover element are curved, the arrangement of the output regions and the patterning provided by the cover element may increase the three- dimensional appearance of the light guide at the major surface.

[00125] In some embodiments, the cover element may have one or more light output regions with a pattern of light blocking elements 224. In some embodiments, these light blocking elements may be approximately the size of the above-described light extracting elements (e.g., micro-optical elements, grooves, etc.), but may instead be formed as opaque and/or reflective areas at the major surface of the cover element. Patterns similar to those described above in connection with FIGS. 6-13 may be provided at the major surface of the cover element, but the density of the light blocking elements would be inverse to that which is described above in the context of light extracting elements.

[00126] In an example, and with reference to FIG. 16, to obtain an effect similar to that described above in connection with the embodiments of FIGS. 6 and 6 A, the cover element may include a rectangular region 1600 with no light blocking elements 224 or a minimal amount of light blocking elements included therein. The rectangular region 1600 may therefore allow all or most of the light output from the light guide extracted from the light guide and incident the rectangular region 1600 to pass therethrough such that it is the brightest in appearance in the fixture. The cover element may include trapezoid-shaped regions 1602, 1604, 1606, 1608 including a pattern of light blocking elements 224 therein, wherein the density of the light blocking elements increases over at least a portion of the region. In an example, the density of the light blocking elements increases (e.g., monotonically) with increasing distance from the rectangular region 1600. This may decrease the apparent brightness of light extracted from the light guide and passed through the cover element with increasing distance from the center, thereby giving the appearance that the center is recessed into the fixture. The cover element also includes four solid light blocking regions 1650, 1652, 1654, 1656 that separate the trapezoid-shaped regions having the pattern of light blocking elements, the solid light blocking regions shaped to give the appearance of structure and depth to the flat light guide. A separation region 1658 may also separate the rectangular region 1600 from the respective trapezoid-shaped regions 1602, 1604, 1606, 1608. Although, in other embodiments, the separation region 1658 may not be present.

[00127] In other embodiments, the regions of the cover element may be configured in a different manner to achieve a different three-dimensional effect. Exemplary reference is made to the respective shapes of the regions described in connection with FIGS. 7-13.

[00128] In still other embodiments, the lighting assembly may include a light guide and a cover element, and both the light guide and the cover element may be patterned to provide an edge lit fixture. [00129] In this disclosure, the phrase "one of followed by a list is intended to mean the elements of the list in the alterative. For example, "one of A, B and C" means A or B or C. The phrase "at least one of followed by a list is intended to mean one or more of the elements of the list in the alterative. For example, "at least one of A, B and C" means A or B or C or (A and B) or (A and C) or (B and C) or (A and B and C).