Field of the Invention

The invention relates to the field of laminated automotive glazing and automotive lighting, specifically, automotive glazing with embedded lighting means.

Background of the Invention

As automotive manufacturers work to meet government regulations for fuel efficiency and emissions, as well as to provide the type of environmentally friendly vehicles that the public is increasingly demanding, reducing weight has been a key strategy. While substituting lighter weight materials has been a big part of the trend, we have also seen a reduction in the average size of most vehicles. As the cabin volume decreases, it can lead to an unpleasant claustrophobic effect. To counter this, manufacturers have been increasing the glazed area of vehicles for several years. The increased viewing area and natural light helps to give the cabin a more open feeling.

The panoramic glass roof has seen rapid growth over the last several years where it has become an exceedingly popular option. A vehicle so equipped has a roof that is comprised substantially of glass. The large panoramic glass roof gives the vehicle an open airy feel as well as a luxurious look. In recent years, on models offered with a panoramic roof option in North American and Europe, the percentage of vehicles sold with this option has been in the 30% to 40% range. Market research predicts that this trend will continue and accelerate over the next several years.

On vehicles with large glass roofs cabin lighting can present a problem. It is often not possible, practical, or desirable to mount a light near the center of the roof due to the need to route the wiring harness, supplying power to the light, across the glazing, to add a cover to hide the harness from the interior of the vehicle and to add a black print to hide the harness from the exterior. Instead, auto makers have been placing lights above the doors and at other locations near the roof. However, the large panoramic roofs tend to encroach on even these areas. LED (light emitting diode) lighting is being used more and more in automotive applications. From ambient cabin lighting to headlamps and signals, the cost, reliability, and intensity of LEDs have reached the point where they are a cost-effective replacement for incandescent bulbs and other conventional lighting technologies. Indeed, with a lifetime as long as 50,000 hours, the LEDs may well last much longerthan the vehicle.

1 In commercial and residential lighting, LED light bulbs have largely replaced incandescent bulbs. While LED bulbs are currently more expensive, the declining price, higher energy efficiency, and long life has given them a short payback period. Commercial and residential lighting fixtures now often incorporate LEDs as a permanent part of the light fixture as the LEDs are expected and likely to outlast the fixture.

Efforts to embed LEDs in laminated glass have had mixed results. One of the primary issues is the omnidirectional nature of an LED. The LED acts as a point source radiating equally in all directions. While this may be acceptable and even desirable for general illumination a more directed beam is desired for specific task lighting such as reading lamps, entry illumination, footwell lighting, etc.

An LED die, laminated in a roof glazing, will radiate over a large area. Light transmission is greatest at 90 degrees with the light perpendicular to the glass surface. As the angle between the light and the glass decreases, the percentage of light transmitted decreases.

At the interface between the glass and air there is a significant mismatch between the index of refraction of the glass and the air. This mismatch results in high reflectivity of light traveling at small angles from the LED. As the angle approaches zero degrees, reflection approaches 100%. This light does not exit the glass but rather is reflected and travels inside of laminate.

Automotive lighting specifications call out the amount of light required per unit area for specific applications. To compensate for the omnidirectional beam and achieve the level of lighting required, we are forced increase the intensity of the source which is undesirable.

Another issue is the high intensity of LEDs intended for general illumination. Due to the small size of the LED die and the difficulty in including any kind of a lens or diffuser in a laminate, the light intensity of the LED die tends to be extremely high. This bright point source can make night driving difficult.

Heat is another issue. While LEDs are much more energy efficient than incandescent lamps, producing far less waste heat, they still generate some heat which must be managed. Glass and the plastic interlayer are both good thermal insulators. As a result, LEDs must be space apart or overheating can occur. A single high intensity LED die may produce too much heat to be used. It is typical to use multiple lower power LED die to lower the thermal density while achieving the desired light intensity.

LEDs do not generally burn out. Rather, as LEDs age, their intensity tends to drop. We define the lifetime of a LED as the time that it takes for its intensity to drop to some

2 percentage of its original. While LEDs do tend to be very consistent electrically, they do have some variation in light output and efficiency due to manufacturing variation. When multiple LEDs are grouped together, any variation in brightness can potentially become noticeable. In the same manner the LEDs may age at a different rate overtime. Even if we were to initially sort and match the LEDs there is no guarantee that they will remain balanced.

As LEDs operate at a low voltage, several are typically connected in series as shown in Figure 6. Due to variation in the resistance of each there will be corresponding variation in the voltage across each die and in the light intensity.

While the expected lifetime is high, a small number of the LEDs may fail. In the event of a failure, the defective LEDs may be very noticeable.

One approach to solve these problems is to move the LED light source to the edge of glass. Light is injected along the edge of glass. The light, traveling parallel to the major surfaces of the glazing is reflected internally with the glazing itself serving as a wave guide. Light is then decoupled by means of various methods to provide for illumination. The issue of variation in intensity is also solved by moving the LEDs to the edge of glass as the decoupling means emits diffused light. There are still the issues of directing the light for task lighting and the general low intensity of the light provided.

Another approach has been to bond an optical component (diffuser, lens, etc.) to the interior glass surface. This allows the light beam to be shaped. While effective, these extra components must be bonded to and optically coupled to the glass surface adding cost and weight to the assembly. They also detract from the aesthetics of the glazing. Being separated from the light source by at least the thickness of the inner glass layer, these optical components are not as effective as they could be due to the losses inside of the glass.

The prior art exhibit examples of embedded LEDs coupled with touch control circuits. An optical component mounted to the inside surface of the glazing may interfere with such a circuit making it undesirable in that type of implementation.

The inner glass layer itself can be modified to form an optical component. This can be done by means of sculpting the surface with a femto-second LASER orthrough localized heating and pressing to form a lens in the glass. Both approaches are not economical and bring their own problems to the implementation including issues with residual stress, glass strength, probability of breakage, optical distortion, aesthetics throughput, and capital investment.

3 It would be desirable to have an illuminated laminate without the drawbacks of the prior art which can also be manufactured with standard automotive glazing equipment, materials, and processes.

Brief Summary of the Invention

The drawbacks of the prior art are solved by means of a laminate comprising a thin, flexible, micro-structured beam shaping layer combined with a lighting means within the laminate. The beam shaping means is located between the glass layers becoming a permanent part of the laminate. It is substantially thin, flexible, and uniform in thickness which facilitates lamination. The beam shaping means comprises at least one micro- structured: film, glass, or coating layer or a combination of film, glass, or coating layers. The term micro-structured is used to describe an object comprising functional features that are difficult if not impossible to observe and view the details of with the naked eye. One of the major surfaces of the film, coating or glass layers of the beam shaping layer may be micro-structured to form optical elements which allow the beam to be shaped as desired. The micro-structure may also apply through at least a portion of the thickness of the beam shaping layer in addition to or in place of micro-structuring of the major surfaces of the beam shaping layer.

Due to the exceedingly small scale of the micro-structures many can be placed close together allowing the beam to be directed over a wide range of angles. The microstructures are based upon well-known and understood optical principles and laws. Methods for designing and producing such micro-structured beam shaping layers are disclosed in US10, 534,114B2, US10,452,025B2, US2018/0188685A1 , US9, 568, 885B2, US9,182,648B2, US8,465,193B1 , and US8,778,706B2.

The micro-structure shapes the beam by shifting the direction of the rays of light emitted from the LEDs. They can be designed to serve as a disperser, blending the light from multiple sources as well as directing the light. The beam shaping layer can be but is not limited to implementation by modifying the surface of a sheet of plastic, such as a polycarbonate or other suitable material, which is compatible with the automotive lamination process. A number of clear plastic films may be used as well as micro- structured thin glass, or a coating or a combination of at least two of the former elements, formed by means of a femto-second or similar LASER. Thus, the glazing may be manufactured by means of standard automotive lamination equipment and with little or no capital investment. The shaped beam also has the advantage of having less stray unwanted light and being able to utilize a lower power light source.

4 This results in an illuminated laminate with targeted illumination performance that can be produced with standard automotive glazing equipment and processes.

Advantages

• Able to meet task illumination requirements

• Low capital investment

• High level of illumination

• Process utilizes standard automotive glazing equipment

• Low level of light leakage to exterior of vehicle

• Improved aesthetics

• Higher energy efficiency

• Lower weight

• Fewer part numbers

Brief Description of the Several Views of the Drawings

The features and advantages of the present invention will become apparent from the detailed description of the embodiments in conjunction with the accompanying drawings, wherein:

Figure 1 A shows a cross section of a typical laminated automotive glazing.

Figure 1 B shows a cross section of a typical laminated glazing with performance film and coating.

Figure 1C shows a cross section of a typical tempered monolithic automotive glazing. Figure 2 illustrates an exploded isometric view of a large panoramic roof. The beam shaping means is implemented in a single sheet of transparent plastic, a reflective coating and a dielectric light diffusing coating.

Figure 3 illustrates an exploded isometric view of a large panoramic roof. The beam shaping means is implemented in a multiple sheet of transparent plastic with one beam shaping layer provided for each set of LEDs and bonded by means of an optical adhesive. The beam shaping means also includes a reflective coating layer and a dielectric diffusing coating layer.

Figure 4 shows a top view of the panoramic roof of Figures 2 and 3.

Figure 5 shows an isometric view of the panoramic roof of Figures 2 and 3.

Figure 6 shows a set of LEDs wired in series with a circular beam shaping means. Figure 7 A shows a cross section of a solar coated laminate with a beam shaping coating and a switchable film.

5 Figure 7B shows a cross section of a solar coated laminate with a beam shaping film adhered between two sheets of plastic interlayer.

Figure 8A shows a cross section of a solar coated laminate having a beam shaping layer optically bonded to the inner glass layer by means of an optical adhesive. Figure 8B shows a cross section of a solar coated laminate with a single plastic interlayer, with the beam shaping layer optically bonded to the inner glass layer by means of an optical adhesive with the beam shaping layer film serving as a carrier for the LEDs. Figure 9A shows a cross section of a solar coated laminate with a beam shaping gradient index lens and a switchable film. Figure 9B shows a cross section of a solar coated laminate with the beam shaping film adhered between two sheet of plastic interlayer and a touch sensor.

Reference Numerals of Drawings

2 Glass 4 Plastic Bonding Layer

6 Obscuration Layer

8 Switchable Film

10 Beam Shaping Coating

12 Performance Film 14 LED Group

16 Connector

18 Performance Coating

20 Beam Shaping Film

22 Carrier Sheet 24 LED

26 Optical Adhesive

28 Wire

30 Beam Shaping Gradient Index Lens

32 Touch sensor 34 Reflector

101 Surface One

102 Surface Two

103 Surface Three

104 Surface Four 201 Outer Layer

6 202 Inner Layer

Detailed Description of the Invention

The following terminology is used to describe the laminated glazing of the invention. Typical automotive laminated glazing cross sections are illustrated in Figures 1 A and 1 B. A laminate is comprised of two layers of glass, the exterior or outer 201 and interior or inner 202 that are permanently bonded together by a plastic bonding layer 4 (interlayer). In a laminate, the glass surface that is on the exterior of the vehicle is referred to as surface one 101 orthe number one surface. The opposite face of the exterior glass layer 201 is surface two 102 or the number two surface. The glass 2 surface that is on the interior of the vehicle is referred to as surface four 104 or the number four surface. The opposite face of the interior layer of glass 202 is surface three 103 or the number three surface. Surfaces two 102 and three 103 are bonded together by the plastic bonding layer 4. An obscuration 6 may be also applied to the glass. Obscurations are commonly comprised of black enamel frit printed on either the number two 102 or number four surface 104 or on both. The laminate may have a coating 18, that provides additional features such as solar control, on one or more of the surfaces. The laminate may also comprise a performance film 12, providing such as reinforcement, color, solar control properties, etc., laminated between at least two plastic bonding layers 4. The types of film that may be used include variable light transmission switchable films 8.

A laminate may have more than two glass layers as is typical in ballistic glazing. In such instances, the additional glass layers and surfaces will be numbered sequentially. Thus, a third glass layer can be used having surfaces five and six for example.

Figure 1C shows a typical tempered automotive glazing cross section. Tempered glazing is typically comprised of a single layer of glass 201 which has been heat strengthened. The glass surface that is on the exterior of the vehicle is referred to as surface one 101 orthe number one surface. The opposite face of the exterior glass layer 201 is surface two 102 or the number two surface. The number two surface 102 of a tempered glazing is on the interior of the vehicle. An obscuration 6 may be also applied to the glass. Obscurations are commonly printed on the number two surface 102. The glazing may have a coating 18 on the number one 101 and /or number two surface 102 (not shown in the figure).

Glazing, in the context of this document shall mean any safety glazing certified to any of the regulatory standards for automotive safety glazing.

7 The structure of the invention is described in terms of the layers comprising the glazing. The meaning of “layer”, as used in this context, shall include the common definition of the word: a sheet, quantity, or thickness, of material, typically of some homogeneous substance and one of several. We also note that the layers are generally substantially flat at least at the macro level.

A layer may further be comprised of multiple layers as in the case of a multi-layer coating such as a solar coating. When multiple layers together provide a common function, the multiple layers may be referred to as a layer even if the multiple layers comprising the layer are not adjacent each other. An example would be a solar protection layer comprising: a solar absorbing glass inner glass layer and a solar reflecting coating applied to the outer glass layer.

A typical laminated windshield comprises two glass layers and a plastic bonding layer (interlayer). An interlayer layer is generally of the same area as the glass layers. The typical laminate may further comprise additional layers including but not limited to coatings and films. The surface area of a layer may be substantially less than that of the glazing. A film layer will have a smaller area than the glass. An obscuration layer will have an area that is substantially less than that of the glass.

Other types of material and components may also be included within the structure. A lighting or heating circuit may be referenced respectively as the lighting layer or the heating layer even though the layer comprises multiple separate components rather than a substantially flat homogeneous sheet of material. In this case, the reference is to the position within the thickness in much the same way that we would reference the floor of a building.

When multiple layers that vary widely in thickness are illustrated, it is not always possible to show the layer thicknesses to scale without losing clarity.

The term “glass” can be applied to many inorganic materials, including many that are not transparent. For this document we will only be referring to transparent glass. From a scientific standpoint, glass is defined as a state of matter comprising a non-crystalline amorphous solid that lacks the ordered molecular structure of true solids. Glasses have the mechanical rigidity of crystals with the random structure of liquids.

Glass is formed by mixing various substances together and then heating to a temperature where they melt and fully dissolve in each other, forming a miscible homogeneous fluid.

Most of the worlds’ flat glass is produced by the float glass process, first commercialized in the 1950s. In the float glass process, the raw ingredients are melted in a large

8 refractory vessel and then the molten glass is extruded from the vessel onto a bath of molten tin where the glass floats.

The types of glass that may be used include but are not limited to the common soda-lime variety typical of automotive glazing as well as aluminosilicate, lithium aluminosilicate, borosilicate, glass ceramics, and the various other inorganic solid amorphous compositions which undergo a glass transition and are classified as glass including those that are not transparent. The glass layers may be comprised of heat absorbing glass compositions as well as infrared reflecting and other types of coatings.

Laminates, in general, are articles comprised of multiple sheets of thin, relative to their length and width, material, with each thin sheet having two oppositely disposed major faces and typically of relatively uniform thickness, which are permanently bonded to one and other across at least one major face of each sheet.

Laminated safety glass is made by bonding two sheets (201 and 202) of annealed glass 2 together using a plastic bonding layer comprised of a thin sheet of transparent thermo plastic 4 (plastic bonding layer) as shown in Figures 1A and 1 B.

Annealed glass is glass that has been slowly cooled from the bending temperature down through the glass transition range. This process relieves any stress left in the glass from the bending process. Annealed glass breaks into large shards with sharp edges. When laminated glass breaks, the shards of broken glass are held together, much like the pieces of a jigsaw puzzle, by the plastic layer helping to maintain the structural integrity of the glass. A vehicle with a broken windshield can still be operated. The plastic bonding layer 4 also helps to prevent penetration by objects striking the laminate from the exterior and in the event of a crash occupant retention is improved.

The glass layers may be strengthened. There are two processes that can be used to increase the strength of glass. They are thermal strengthening, in which the hot glass is rapidly cooled (quenched) and chemical tempering which achieves the same effect through an ion exchange chemical treatment.

Heat strengthened, full temper soda-lime float glass, with a compressive strength in the range of at least 70 MPa, can be used in all vehicle positions other than the windshield. Heat strengthened (tempered) glass has a layer of high compression on the outside surfaces of the glass, balanced by tension on the inside of the glass which is produced by the rapid cooling of the hot softened glass. When tempered glass breaks, the tension and compression are no longer in balance and the glass breaks into small beads with dull edges. Tempered glass is much stronger than annealed laminated glass. The thickness limits of the typical automotive heat strengthening process are in the 3.2 mm

9 to 3.6 mm range. This is due to the rapid heat transfer that is required. It is not possible to achieve the high surface compression needed with thinner glass using the typical blower type low pressure air quenching systems.

A wide range of coatings, used to enhance the performance and properties of glass, are available and in common use. These include but are not limited to anti-reflective, infrared reflecting, hydrophobic, hydrophilic, self-healing, self-cleaning, anti-bacterial, antiscratch, anti-graffiti, anti-fingerprint, and anti-glare.

Methods of application of a coating include Magnetron Sputtered Vacuum Deposition (MSVD) as well as others known in the art that are applied via pyrolytic, spray, Controlled Vapor Deposition (CVD), dip, sol-gel, and other methods.

The glass layers are formed using gravity bending, press bending, cold bending or any other conventional means known in the art. In the gravity bending process, the flat glass is supported near the edge of glass and then heated. The hot glass sags to the desired shape under the force of gravity. With press bending, the flat glass is heated and then bent on a full of partial surface mold. Air pressure and vacuum are often used to assist the bending process. Gravity and press bending methods for forming glass are well known in the art and will not be discussed in detail in the present disclosure.

The plastic bonding layer 4 has the primary function of bonding the major faces of adjacent layers to each other. The material selected is typically a clear thermoset plastic. For automotive use, the most commonly used plastic bonding layer 4 (interlayer) is polyvinyl butyral (PVB). PVB has excellent adhesion to glass and is optically clear once laminated. It is produced by the reaction between polyvinyl alcohol and n-butyraldehyde. However, PVB by itself, it is too brittle. Plasticizers must be added to make the material flexible and to give it the ability to dissipate energy over the temperature range required for an automobile. Only a small number of plasticizers are used. They are typically linear dicarboxylic esters. Two in common use are di-n-hexyl adipate and tetra-ethylene glycol di-n-heptanoate. A typical automotive PVB interlayer is comprised of 30-40% plasticizer by weight.

In addition to polyvinyl butyl, ionoplast polymers, Ethylene Vinyl Acetate (EVA), Cast in Place (CIP) liquid resin and thermoplastic polyurethane (TPU) can also be used. Automotive plastic bonding layers are made by an extrusion process which has a thickness tolerance and process variation. As a smooth surface tends to stick to the glass, making it difficult to position on the glass and to trap air, to facilitate the handling of the plastic sheet and the removal or air (deairing) from the laminate, the surface of the

10 plastic is normally embossed contributing additional variation to the sheet. Standard thicknesses for automotive PVB interlayer are 0.38 mm and 0.76 mm (15 and 30 mil). When a film or other material needs to be included within the laminate more than one interlayer sheet may be required to accommodate the thickness of the added film or material. While much depends upon the various process and product variables, in general, one can laminate an object that has a thickness that is no greater than 1/3 of the total thickness of the plastic interlayers. In the case of a film, if the film extends substantially to the edge of glass, the thickness is not so much of a problem. It is the change in thickness that causes optical distortion and breakage. Still, an additional layer of interlayer is needed to bond the two major surfaces of the film to the glass layers. An object that has a surface area that is substantially less than that of the interlayer and which is sufficiently thin, may be bonded to one of the glass surfaces by means of an adhesive and laminated with a single plastic interlayer sheet.

Plastic bonding layers are available with enhanced capabilities beyond bonding the glass layers together. The invention may include interlayers designed to dampen sound. Such interlayers are comprised whole or in part of a layer of plastic that is softer and more flexible than that normally used. The interlayer may also be of a type which has solar attenuating properties.

A wide variety of performance films 12 are available that can be incorporated into a laminate. The uses for these films include but are not limited to solar control, variable light transmission, increased stiffness, increased structural integrity, improved penetration resistance, improved occupant retention, providing a barrier, tint, providing a sunshade, color correction, and as a substrate for functional and aesthetic graphics. The term “film” shall include these as well as other products that may be developed or which are currently available which enhance the performance, function, aesthetics, or cost of a laminated glazing. Most films do not have adhesive properties and therefore need to be combined with other adhesives such as optical clear adhesives or plastic bonding layers.

The beam shaping means, when comprised of a film, may make use of a performance film as described above which has been treated and altered to create the optical elements needed or a film so modified that serves no other purpose.

One type of performance film that may be used with the laminate of the invention is variable light transmission film also known as switchable film 8.

To control the level of light transmission through the laminate, there are many technologies available: electrochromic, photochromic, thermochromic and electric field

11 sensitive films which are designed to be incorporated into laminated glass. Of interest are suspended particle device (SPD) films and polymer dispensed liquid crystal (PDLC) films which can quickly change their light transmittance in response to an electrical field. SPD is a variable tint technology with which the level of tint can be controlled and varied in response to an applied electrical field. SPD goes from dark in the off state to less dark in the on state. In an SPD film, microscopic droplets of liquid containing needle like particles, light valves, are suspended in a matrix. In the off state the particles are in a random state of alignment and block the transmission of light. The degree of alignment and resulting tint can be varied in response to the applied voltage. The light transmittance in the on and off states can also be shifted through changes to the thickness and composition of the active material. In the off state, it is still possible to see clearly through SPD.

SPD glazing is produced by adding a special film to a laminate. The typical construction of the film is comprised of the active material sandwiched between two thin plastic layers having a transparent conductive coating on each. The film is laminated in between two plastic bonding layers to form a laminated glazing.

PDLC is a light scattering technology which goes from opaque in the off state to clear in the on state. In a PDLC film, microscopic droplets of liquid crystal are suspended in a polymer matrix. In the off state the liquid crystals are in a random state of alignment and scatterthe light providing privacy. In the off state, the film is substantially opaque. When an electric filed is applied, the crystals align and allow light to pass. The degree of scattering can be varied by varying the amplitude of the applied voltage. The level of light transmittance in the on and off states can also be shifted by making changes to the thickness and composition of the active material. PDLC is primarily a privacy product though it can also be used for solar control as it reduces the solar energy transmitted. Laminates that incorporate these variable light transmittance technologies are sometime referred to as “smart” glass or switchable glass.

Automotive glazing often makes use of heat absorbing glass compositions to reduce the solar load on the vehicle. While a heat absorbing window can be highly effective the glass will heat up and transfer energy to the passenger compartment through convective transfer and radiation. A more efficient method is to reflect the heat back to the atmosphere allowing the glass to stay cooler. This is done using various infrared reflecting performance films and coatings. Infrared coatings and films are generally too soft to be mounted or applied to a glass surface exposed to the exterior of the vehicle.

12 Instead, they must be fabricated as one of the internal layers of a laminated product to prevent damage and degradation of the film or coating.

One of the big advantages of a laminated window over a tempered monolithic glazing is that a laminate can make use of infrared reflecting coatings and films in addition to heat absorbing compositions and interlayers.

Infrared reflecting coatings include but are not limited to the various metal/dielectric layered coatings.

Infrared reflecting performance films include both metallic coated plastic substrates as well as organic based non-metallic optical films which reflect light in the infrared wavelength range.

The glazing of the invention may comprise any combination of coatings, plastic bonding layers, performance films, glass compositions and treatments as described.

A panoramic roof is a roof that is comprised substantially of glass. The roof glazing may be comprised of a single or multiple glazing. One or more of the roof glazings may be fixed or movable. The glazings may be laminated, tempered or a mixture of both types. Likewise, the glazings may be monolithic or laminated.

A panoramic windshield is a windshield on which the top edge has been substantially extended such that it comprises a portion of the vehicle roof.

While the focus of the disclosure and embodiments is on panoramic roof glazing, the invention may be implemented on a panoramic windshield or in any of the other laminated glazing positions of the vehicle such as a conventional sunroof, windshield, sidelites or backlites

The invention claimed is an illuminated laminate with beam shaping to improve the quality of the light provided. The lighting and beam shaping means are embedded within the laminate.

The lighting mean of the present disclosure comprises but is not limited to Light Emitting Diodes (LED), but should also be understood that may be other kind of means to generate light.

While LEDs have been in commercial use for over 50 years, it has only been in more recent years that the durability, cost, size, color, light intensity, and lifetime have improved to the point where the technology can compete with other forms of lighting such as incandescent. Indeed, the price point has been reached where LED bulbs for home and commercial lighting have a relatively short payback period from energy savings. For the most part, adaptation has been through installation of LED bulbs that are compatible with lighting devices that were originally designed for incandescent lighting. Ironically,

13 most of these new states of the art lighting devices utilize Edison screw type threaded bases which are substantially the same as when they were first introduced in 1909.

The screw type base made perfect sense as the early carbon filament incandescent lights had a lifetime that was measured in hours. While the technology has vastly improved over the years, modern tungsten filament bulbs have a lifetime that is rated in the 500-2000-hour range so it still makes sense to have replaceable bulbs in lighting devices that are designed for incandescent bulbs.

In automotive applications, due to the extremes of temperature, shock and vibration, incandescent bulbs are even more prone to failure than in static indoor installations. In automotive applications, LEDs have a major advantage as they are less susceptible to temperature extremes, shock, and vibration. An important additional benefit is that an LED reaches full brightness in less time than an incandescent bulb. While the difference is just a fraction of a second, in a vehicle traveling at a high rate of speed, it can make the difference between life and death. LED replacement bulbs for signals and cabin lighting have been available in the automotive aftermarket for several years. Many early adaptors were willing to pay a premium to replace their incandescent bulbs with LED bulbs. Early OEM automotive applications were the brake lights where the faster rise time improved safety. Today we can find LED lighting in use in almost all of the traditional automotive light positions including head lamps. LED lighting is especially of value in battery powered vehicle where the higher efficiency and lower weight translates into extended mileage range.

The estimated lifetime of current production LEDs today is as high as 50,000 hours. Unlike incandescent bulbs, the end of life is not when the bulb stops producing light but when the intensity of the light drops to 70% of the original value. Over the typical life of an automotive vehicle, the LED will outlast the vehicle in most application. However, even though the bulb will outlast the vehicle, automotive lighting fixtures are manufactured to accept bulbs with the same replaceable base and socket design of their incandescent predecessors.

As the quality and durability of other automotive components has improved, we are seeing some adaptations in design and manufacture in response to the extended lifetimes. Drive shafts, control arms and other assemblies are often manufactured such that the individual components that comprise the assembly are not replaceable. When one of the components fails, the entire assembly must be replaced. This helps to reduce the initial cost of the assembly and the weight as well as reducing the part count.

14 Attempts have been made to incorporate LED lighting as an integral permanent part of other components such as adding LEDs to laminated glass. All windshields are made from laminated glass. Laminated glass is also sometimes used for door windows, backlites, sunroofs, and panoramic roofs.

The bonding layer used for most automotive laminates has a thickness of 0.76 mm (30 mils). The actual LED chip is thinner and so can be incorporated into the bonding layer. The problems associated with commercializing this technology have been primarily in supplying power to the LEDs.

One method that has been found to achieve excellent results makes use of CNC (Computer Numeric Control) machine technology to produce a sheet of thermoplastic containing LEDs that is subsequently laminated between two glass layers. The CNC requires movement of the tool in the up/down, left/right, and forwards/backwards directions (X, Y & Z) as well as a rotary axis perpendicular to the bed and a tool changer and tools to embed the wire, cut the wire, place the LED chips, and connect the LED chips to the wires. Machines with this capability are commercially available. Such machines are also used to produce articles with embedded wire antennas and electronics for RFID (Radio Frequency Identification), applications such as passports, identification cards and admission tickets.

The CNC machine removes the LED chips from a reel and then places them on the plastic sheet in much the same way as a pick and place robot is used to populate printed circuit boards with component. The sheet is held flat and in place by means of vacuum holes on the bed of the machine.

After the LEDs have been placed, the tool is changed, and the wire is dispensed connecting the LEDs and forming the circuits to power the LEDs. The wire used is a fine, black, drawn, solid, uninsulated, Tungsten wire, the same as used to make the filaments of incandescent lights. The wire is substantially embedded in the plastic sheet using heat and pressure. Ultrasound may also be used in conjunction with pressure to embed the wire in addition to or in place of heat. The wire may be cut by mechanical means, using a LASER, or any other cutting means. Using a LASER, the wire for the entire circuit can be dispensed as a single continuous length and then afterward all the cuts can be made. A LASER can also be used to weld the wire to the LEDs.

The selection of Tungsten for the power wiring may appear counter intuitive due to its relatively high resistivity as compared to Copper. However, while the resistivity of Tungsten is three times that of Copper, the tensile strength is twelve times that of Copper. The higher strength allows for the wire to be embedded at a much higher speed and to

15 withstand handling during assembly better with a lower probability of breakage as well as to withstand the stress of the lamination process. The wire is electrically connected to the LEDs by means of a conductive adhesive, crimping, welding, soldering or other suitable means. Even with the higher resistance of the Tungsten, due to the low power requirements of the LEDs, a very thin wire can still be used. The wire is largely hidden by the black obscuration. Where the wire does encroach on the daylight opening, it is substantially invisible.

Flexible circuits, like those employed in commercial consumer electronic goods, are used to make the electrical connections to the wires and to bring the connections out from inside ofthe laminate.

An alternate method makes use of the beam shaping layer using it as a carrier for the LED die and electrical connections. Touch sensitive areas can also be included on the same carrier. A cross section illustrating this concept is shown in Figure 8B where the beam shaping film 20 is optically bonded to the inner glass layer 202. This is especially advantageous when only a small number of illuminated areas are required as may be the case in a backlite with the high mounted stop light (CHMSL).

While the discussion has been focused on interior illumination, the invention may also be employed for the purpose of exterior illumination needs such as signaling. Such signals may be intended to provide information to the occupants or to other drivers. As an example, a backlite implementing the claims of the invention may comprise an embedded LED high mounted brake light with a beam shaping means which diffuses the light from multiple LEDs as well as directing the beam in the direction of trailing vehicles. Figure 8B also shows the use of a reflector 34. The reflector may comprise a reflective film bonded to the glass or a reflective coating applied to the glass. In this example, the reflector is used to increase the intensity of light. The reflector could be used in some embodiments to enhance the light illumination on one specific region.

Touch control sensors 32 can optionally be embedded in the plastic bonding layer as well without interference from the beam shaping layer if a non-conductive material is used in the construction of said layer such as illustrated in Figure 9B. If a conductive material is used, then the beam shaping layer may be employed as a part of the touch sensitive circuit.

The plastic layers must also be able to remain clear for the life of the vehicle. Several such plastics are known. A partial list includes but is not limited to polycarbonate, acrylic, PET, PMMA, PVB, PU, EVA, and methacrylate. More generally speaking, any

16 transparent elastomers that can meet automotive lamination and durability specifications may be used.

Beam shaping films are known in the art. Various types are manufactured by multiple companies. The products go under various names including but not limited to: Direction Turning Film, Image Directing Film and Light Shaping Diffuser. They are commonly used in displays, traffic signals and backlights to direct an image, to diffuse light or to shift a beam of light. Some work to alter the angular distribution characteristics of a beam of light by means of a microscopic Fresnel prism structure. Others reproduce a holograph on the surface of the plastic. We shall use the term “sheet” to denote said films.

The beam shaping film of the invention, in some embodiments, may be made from an optically clear plastic that is compatible with the automotive lamination process, has good adhesion to automotive interlayer and high visible light transmission. Suitable plastics include by are not limited to PMMA, PVB, PU, EVA, and methacrylate. More generally speaking, any transparent elastomers that can meet automotive lamination and durability specifications may be used.

The surface of the beam shaping means may be altered, to form optical micro-structures, by means developed and employed in the semi-conductor and display industry. The optical structures of the beam shaping means are designed both empirically and using optical modeling software. These optical micro-structures are responsible for “shaping” the beam rays redirecting them in a desired way to either result in light focus or light diffusion or both.

Due to the optical elements, the beam can be directed over a wide range of angles. The structures are based upon well-known and understood optical principles and laws. The structures shape the beam by shifting the direction of the rays of light emitted from the LEDs. They can also be designed to serve as a disperser, blending the light from multiple sources as well as directing the light. The beam shaping means may be implemented by modifying the surface of a sheet of film, such as a polycarbonate or other suitable material, which is compatible with the automotive lamination process. Several clear plastics may be used as well as micro-structured thin glass, formed by means of a femtosecond or similar LASER. The beam shaping means may also be implemented in a coating. A combination of a film and a coating may be used to form the beam shaping means as well. The surface of a glass layer may also be altered to serve as an element of the beam shaping means.

17 A coating may be micro-structured by means of a LASER to form optical structures that refract the light. As an example, a sufficiently thick silica coating may be micro-structured by means of a femto-second LASER to form microscopic Fresnel prisms.

The beam shaping means may be implemented as a single large sheet extending substantially to as far as the edge of glass. The extended optical layer may comprise unmodified surface areas where beam shaping structures are not needed. This allows for a single large sheet to be produced which can then be easily and accurately indexed and assembled into the laminate precisely locating the individual modified surface beam shaping areas of the sheet.

Alternately, the beam shaping means may be implemented as multiple separate films, coating layers or treated glass layer areas with each located in the area immediate to and in the path of the light emitted from the LEDs. Individual sheets may overlap multiple LEDs and/or groups of LEDs.

In addition to forming the surface of a beam shaping means layer to create optical structures, it is also possible to form a Gradient-index (GRIN) lens, in which the refractive index is gradually decreased from the center region to the edge/peripheral region and which can be formed in a glass, film or coating layer.

A polymer coating with partial polymerization can be used to form a beam shaping means (beam shaping layer). In this process, a monomer is partially polymerized or partially cross-linked using UV Light or Laser Light at varying intensities from center to edge region to give a refractive gradient. Examples of polymer coating include acrylic and polyurethane. Coating methods include Spray, Dip, Slot Die, etc.

Likewise, the same effect can be achieved in an Si0 ₂ coating with gradient doping of Ti0 ₂ . In the center region, the doping concentration of Ti0 ₂ is highest and therefore the refractive index is highest. By gradually varying the doping concentration of Ti0 ₂ from the center to the edge, (high doping to low doping, from center to edge), a GRIN flat surface lens is created. Coating methods include Chemical Vapor Deposition (CVD), Spray.

Ion Exchange with molten salt with Lithium ions can also selectively alter the refractive index of the glass surface. In this process, Sodium ions in the glass are partially exchanged with Lithium ions, with a larger amount of exchange occurring at the edge of the optical structure. The glass obtains a gradient material structure and a corresponding gradient of the refractive index.

Ion Implantation can also be used to alter the index of refraction. The refractive index of Silicate glass or silica (Si0 ₂ ) can be tuned by implanting with ions of Ga or Ar. A gradient

18 of refractive index can be obtained by varying the incident energies and doses of ion implantation.

The beam shaping means may be comprised of one or more films, coatings, glass layers or combination of films, coatings, and glass layers just as an optical lens may be comprised of multiple elements. Regardless of the number of separate films/sheets/glass layers, we shall refer to them in the singular as they work together as a system. As an example, a beam shaping means may comprise: a reflective coating on surface two, an optical film between the LEDs and the number three surface and a coating on the number three surface.

A coating may be applied to one or more to at least a portion of the glass surfaces to create a reflector or to serve as a light diffuser.

In a standard two glass layer automotive laminate, the beam shaping means, other than a reflective element if used, must be located between the LEDs and surface two orthree of the laminate. Surface three if the light is to be directed towards the interior of the passenger compartment, surface two if towards the vehicle exterior.

The beam shaping means layers must be optically bonded to the adjacent layers of the laminate. With a beam shaping film, this can be accomplished by means of an additional plastic bonding layer as is often done when performance films are used. This additional plastic bonding layer can also serve as a carrier sheet 22. In the case of a beam shaping coating, the coating itself is formulated and applied in a mannerthat will achieve sufficient adhesion to the glass layers and the plastic bonding layer.

If there is only a single LED group or a small number, it may be advantageous to just produce the beam shaping layer to the minimum size needed. In this case, the beam shaping layer must be precisely placed on the plastic bonding layer/ carrier sheet 22 or precisely located on the glass surface and optically bonded therein.

The beam shaping means may be designed to function as just a diffuser. In this case, the beam is shaped by blending and dispersing the beams coming from the LEDs. In this manner, we can minimize the effect of non-uniform aging, manufacturing variation or the failure of a single LED in a group of multiple LEDs. This may be a preferred option for general cabin illumination where it is desirable to scatter the light over a large area. The beam shaping means may also be designed to shift the direction of the beam. In this manner the beam can be directed and focused to increase the intensity in the target area while reducing unwanted stray light. In this instance, the beam shaping means must contain optical elements that function as a lens.

19 In areas where it is not desired to have light emitted from the opposite glass surface, the black obscuration may be printed to block the light. Conversely, a reflective coating or reflecting means may be applied to increase the light directed in the desired direction. The phrase beam shaping shall include any and all of the means that may be used to change the direction of the light being emitted from the lighting means including but not limited to means that focus, disperse, diffuse, reflected, diffract, refract or otherwise shape the light with the limitation that said means must be suitable for implementation in a form that is suitably thin and flat so as to facilitate lamination between the glass layers of the laminate.

It should be noted that other means of illumination may be used in place of the LEDs of the described embodiments and this disclosure without departing from the concept of the invention. Any means that can provide the intensity and packaging requirements may be utilized including, OLEDs, electro luminescent, fiber optics, light pipes and even means not yet invented such that can provide light and may be connected and embedded in the laminate. We shall refer to these as laminate embedded lighting means.

Description of Embodiments Produced by the Method

1 . Embodiment one, a large panoramic laminated roof, is shown in Figures 2, 4 and 5. The roof has two glass 2 layers. The exterior glass layer 201 is 2.3 mm thick clear soda-lime glass with an MSVD solar control coating 18 on surface two 102. The interior glass layer is 2.1 mm thick solar green soda-lime glass. Both glass layers are bent to shape by means of a singlet pressing process and thermally strengthened but not fully tempered. Surface two 102 of the outer glass layer 201 and surface four 104 of the inner glass layer 202 are each screen printed with a black obscuration band 6 as shown in the figures.

Groups of LEDs are embedded in the plastic bonding layer 4. Each LED group 14 comprises a set of five LED dies 24 connected in series as shown in Figure 6. Eleven sets of three groups 14 each are used. The LEDs 24 are wired using a 200-micron diameter Tungsten wire 28. The LED die 24 and wire 28 are embedded in a sheet of automotive PVB with a thickness of 0.76 mm. The PVB plastic bonding layer 4 has a grey tint having a visible light transmission of 40% which helps to hide the wires and LEDs. The PVB plastic bonding layer 4 with the embedded wire and LEDs is positioned such that the LEDs are on the side of the PVB layer 4 facing the vehicle interior. The wires terminate in a flexible circuit exiting the edge of glass at the center rear which joins to a multipin, watertight, locking automotive connector 16.

20 A 0.24 mm thick sheet of polycarbonate plastic film is used to form the beam shaping layer 20. In the immediate area of each set of LED groups, the surface of the sheet is modified at the microscopic level to form beam shaping micro-structures. Alternately, the beam shaping elements may be fabricated separately and then bonded to a carrier sheet 22 rather than forming all from a single sheet.

The set of LEDs at the center of the roof acts as a replacement for the traditional dome light. The light is shaped such as to diffuse and radiate in a 160-degree cone. There is one set of LEDs positioned above each of the door locations. These serve to illuminate the entry when the door is opened. The beam shaping elements for these diffuse and direct the beam in an elongated oval shape. There are also six sets of lights intended for reading or task illumination located on either side of the front to back centerline. These also are provided with a beam shaping element that diffuses and focuses the light in a narrow cone.

An exploded view is shown in Figure 2 where we can see the beam shaping layer 20, and the additional plastic bonding layer 4 that is needed to bond the beam shaping layer 20 to the inner glass layer 202. The opposite major face of the beam shaping layer on the carrier sheet is bonded to the laminate by the plastic bonding layer 4 that the LED circuits are embedded in.

2. Embodiment two is illustrated in Figures 3, 4 and 5. It differs from embodiment one in that only a single sheet of PVB plastic bonding layer 4 is required. The beam shaping layer 20 is implemented as separate film elements for each LED set. Further, the LEDs are attached to the PVB plastic bonding layer. Each beam shaping film 20 film is bonded to surface three 103 of the inner glass layer 202 by means of an optical adhesive 26. Each group is also provided with a reflector 34 on surface two (similar to the one shown in Figure 8B).

3. Embodiment three differs from embodiment one only in that each LED group also has a capacitive touch sensor within the laminate. A cross section of a laminate with a capacitive touch sensor 32 is shown in Figure 9B.

4. Embodiment four differs from embodiment one in that it further comprises a switchable layer 8 and with the exception that the carrier layer and the beam shaping means are replaced by a beam shaping coating 10 on surface three 103. A cross section of a laminate with these features is shown in Figure 7 A.

21 5. Embodiment five differs from embodiment four in that it = comprises a beam shaping gradient index layer 30 instead of a beam shaping coating 10. A cross section of a laminate with these features is shown in Figure 9A.

6. Embodiment six differs from embodiment one in that it further comprises a third plastic interlayer as may be required based upon the manufacturing process. A cross section is shown in Figure 7B. As can be appreciated, numerous further embodiments can be made by the various combinations of beam shaping elements including various types of reflector and diffuser layers, optically micro-structured glass, film and coating layers and gradient index of refraction lens glass, film, and coatings. Any and all of the full factorial of combinations are obvious considering this disclosure and thus are claimed without enumeration of each individual combination.

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