阅读说明：本技术 支持两步磷光体沉积以形成led矩阵阵列的光刻胶图案化工艺 (Photoresist patterning process supporting two-step phosphor deposition to form LED matrix array ) 是由 D·B·罗伊特曼 E·多纳 清水健太郎 M·R·博默 于 2019-12-17 设计创作，主要内容包括：描述了一种用于硅树脂结构的低温固化的方法,包括在衬底上提供图案化光刻胶结构的步骤。光刻胶结构限定了可以至少部分地填充有缩合固化硅树脂体系的至少一个开放区。气相催化剂沉积用于加速缩合固化硅树脂的固化,并且去除光刻胶结构以留下独立或分层的硅树脂结构。该方法实现了包含硅树脂结构的磷光体,该硅树脂结构可涂敷有反射金属或其他材料。(A method for low temperature curing of silicone structures is described, comprising the step of providing a patterned photoresist structure on a substrate. The photoresist structure defines at least one open area that can be at least partially filled with a condensation-cured silicone system. Vapor phase catalyst deposition is used to accelerate the cure of the condensation-cured silicone and the photoresist structure is removed to leave a freestanding or layered silicone structure. The method achieves a phosphor comprising a silicone structure that may be coated with a reflective metal or other material.)

1. A method of making a phosphor pixel array, the method comprising:

in a first phosphor deposition step, depositing and patterning a photoresist layer to form an array of photoresist blocks, the photoresist blocks being separated from each other by gaps, the photoresist blocks and the gaps occupying alternating positions in a matrix array and forming a checkerboard pattern;

depositing a first phosphor composition in the gap, the first phosphor composition comprising phosphor particles dispersed in a condensation-cured silicone system;

after depositing the phosphor composition, curing the condensation-cured silicone system using one or more vapor phase catalysts to form a first plurality of phosphor pixels occupying alternating positions in the matrix array;

removing the photoresist block after curing the condensation-cured silicone system;

depositing a reflective structure on sidewalls of the first plurality of phosphor pixels after removing the photoresist block;

after depositing the reflective structure, depositing a second phosphor composition in a second phosphor deposition step at locations in the matrix array previously occupied by photoresist blocks; and

curing the phosphor composition deposited in the second phosphor deposition step to form a second plurality of phosphor pixels occupying alternating positions in the matrix array, wherein adjacent phosphor pixels in the matrix array are in contact with and separated by one of the reflective structures.

2. The method of claim 1, wherein the condensation-cured silicone system comprises an organosiloxane block copolymer.

3. The method of claim 1, wherein the one or more gas phase catalysts comprise a superbase catalyst.

4. The method of claim 1, wherein the one or more gas phase catalysts comprise 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU).

5. The method of claim 1, wherein the second phosphor composition is the same as the first phosphor composition.

6. The method of claim 1, wherein the second phosphor composition is different from the first phosphor composition.

7. The method of claim 1, wherein the first phosphor composition, when excited, emits light of a first color, the second phosphor composition, when excited, emits light of a second color, and the second color is different from the first color.

8. The method of claim 1, wherein:

the second phosphor composition includes phosphor particles dispersed in a condensation-cured silicone system; and

curing the phosphor composition deposited in the second phosphor deposition step includes using one or more vapor phase catalysts.

9. The method of claim 1, wherein adjacent phosphor pixels are separated by less than or equal to about 10 microns by the reflective structure.

10. The method of claim 1, wherein adjacent phosphor pixels are separated by less than or equal to about 3 microns by the reflective structure.

11. The method of claim 1, wherein the reflective structure comprises scattering particles dispersed in a matrix.

12. The method of claim 1, wherein the reflective structure comprises a reflective metal layer.

13. The method of claim 1, wherein the reflective structure comprises a distributed bragg reflector structure.

14. A method of forming a phosphor converted LED array comprising attaching an array of phosphor pixels prepared by the method of claim 1 to a corresponding array of light emitting diodes.

15. A phosphor pixel array, comprising:

a plurality of phosphor pixels spaced apart from one another, each phosphor pixel including a sidewall facing an adjacent pixel in the array; and

a plurality of reflective structures disposed between the sidewalls of adjacent phosphor pixels;

wherein a spacing between adjacent phosphor pixels is equal to a thickness of the reflective structure disposed therebetween, the thickness being less than or equal to about 3 microns.

16. The matrix array of phosphor pixels according to claim 15, wherein said reflective structure comprises a distributed bragg reflector structure.

17. The matrix array of phosphor particles of claim 15, wherein the reflective structure comprises one or more reflective metal layers.

Technical Field

The present disclosure generally relates to a patterning process that allows for the curing of silicone or siloxane without substantially compromising the release properties of the patterned photoresist. Fabricating a reflective wall phosphor pixel array for an LED matrix array is one embodiment implemented using the disclosed patterning process.

Background

Low temperature patterning of silicone using conventional positive photoresists can be difficult. The temperature required to cure the silicone is typically higher than that required to ensure clean removal of the photoresist, thereby preventing the widespread use of photoresist patterned silicone. A process is needed that allows for low temperature curing of the silicone in conjunction with photoresist patterned structures.

This limitation may prevent semiconductor Light Emitting Devices (LEDs) from being patterned using photoresist. The LED array may be fabricated to include pixels formed by a combination of an LED array and a stacked array of phosphors embedded in silicone. However, since the temperatures required to cure the phosphor containing silicone are typically higher than those required to ensure clean removal of the photoresist, there is a need for an improved process for patterning the silicone using a photoresist structure.

As another example, to improve the efficiency and operation of LEDs, light from the LED array may be arranged to pass from the top of each member of the LED array through a separately matched phosphor/silicone array, with a certain percentage being wavelength converted to provide the required spectral output. Typically, a certain proportion of the light is lost by reflection or direct transmission out the sides of the phosphor layer. To minimize such losses and cross-talk with neighboring pixels, a reflective material may be used to coat the sidewalls of each pixel of the phosphor/silicone array. However, when the LEDs are positioned in close proximity to each other in the array, it is difficult to uniformly coat the sidewalls. There is a need for improved processes and structures that allow the use of photoresist structures to form such reflective coated phosphor/silicone structures.

Disclosure of Invention

According to an embodiment of the invention, a method for low temperature curing of a silicone structure is described, comprising the step of providing a patterned photoresist structure on a substrate. The photoresist structure defines at least one open area that can be at least partially filled with a condensation-cured silicone system. Gas phase catalysis is used to cure condensation-cured silicone systems, removing the photoresist structure to leave a freestanding or layered silicone structure.

In some embodiments, the condensation-cured silicone system further comprises an organosiloxane block copolymer.

In some embodiments, the gas phase catalysis further comprises the use of a superbase catalyst, which may include, but is not limited to, the use of 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU).

In another embodiment, a method for defining a phosphor comprising a silicone structure adapted to receive light from an LED element is disclosed. The method includes the step of providing a patterned photoresist structure on a substrate, wherein the photoresist structure defines at least one open region. The at least one open area is at least partially filled with phosphor particles comprising a condensation-cured silicone system. The condensation cure silicone system may then be cured after or simultaneously with the vapor phase catalyst deposition. The photoresist structure is removed and the silicone-bonded phosphor particles are coated with a reflective material. The cavity defined by the structure of bonded phosphor particles may be filled with additional bonded phosphor particles, leaving vertical walls of reflective material.

In some embodiments, the checkerboard structure may be defined by a combination of phosphor particles coated with a reflective material. The reflective material may be removed from the top or bottom of the checkerboard structures to leave vertically arranged walls of reflective material positioned only between the checkerboard structures.

Drawings

Non-limiting and non-exhaustive embodiments of the present disclosure are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

Fig. 1 shows a schematic cross-sectional view of an example pcLED.

Fig. 2A and 2B show a schematic cross-sectional view and a schematic top view, respectively, of a pcLED array.

Fig. 3A shows a schematic top view of an electronic board on which a pcLED array may be mounted, and fig. 3B similarly shows the pcLED array mounted on the electronic board of fig. 3A.

Fig. 4A shows a schematic cross-sectional view of a pcLED array arranged relative to a waveguide and a projection lens. Fig. 4B shows an arrangement similar to that of fig. 4A, without the waveguide.

Fig. 5 is a flow chart illustrating an example process for patterning silicone using a photoresist structure.

Fig. 6A, 6B, 6C, 6D, 6E, 6F, and 6G illustrate steps in an example method of fabricating a silicone and phosphor structure for an LED package.

Fig. 7 illustrates the intermediate checkerboard structure prior to filling with the silicone and phosphor materials.

Detailed Description

The following detailed description should be read with reference to the drawings, in which like reference numerals refer to like elements throughout the various figures. The drawings, which are not necessarily to scale, depict alternative embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, and not by way of limitation, the principles of the invention.

Fig. 1 shows an example of a stand-alone pcLED 100 including a semiconductor diode structure 102, referred to herein collectively as an "LED", disposed on a substrate 104, and a phosphor layer 106 disposed over the LED. The semiconductor diode structure 102 generally includes an active region disposed between n-type and p-type layers. Application of a suitable forward bias across the diode structure results in light being emitted from the active region. The wavelength of the emitted light is determined by the composition and structure of the active region.

The LED may be, for example, a group III-nitride LED that emits blue, violet, or ultraviolet light. LEDs formed from any other suitable material system and emitting light at any other suitable wavelength may also be used. Other suitable material systems may include, for example, group III-phosphide materials, group III-arsenide materials, and group II-VI materials.

Any suitable phosphor material may be used, depending on the desired light output from the pcLED.

Fig. 2A-2B show a cross-sectional view and a top view, respectively, of an array 200 of pcleds 100 comprising phosphor pixels 106 disposed on a substrate 202. Such an array may comprise any suitable number of pcleds arranged in any suitable manner. In the illustrated example, the array is depicted as being monolithically formed on a shared substrate, but alternatively the array of pcleds may be formed from separate individual pcleds. The substrate 202 may optionally include CMOS circuitry for driving the LEDs and may be formed of any suitable material.

As shown in fig. 3A-3B, the pcLED array 200 may be mounted on an electronic board 300, the electronic board 300 including a power and control module 302, a sensor module 304, and an LED attachment region 306. The power and control module 302 may receive power and control signals from an external source and signals from the sensor module 304, based on which the power and control module 302 controls the operation of the LEDs. The sensor module 304 may receive signals from any suitable sensor, such as from a temperature or light sensor. Alternatively, the pcLED array 200 may be mounted on a separate board from the power and control module and the sensor module (not shown).

The individual LEDs may optionally be combined or arranged in combination with a lens or other optical element positioned adjacent to or disposed on the phosphor layer. Such an optical element, not shown in the figures, may be referred to as "primary optical element". In addition, as shown in fig. 4A-4B, the pcLED array 200 (e.g., mounted on the electronic board 300) may be arranged in combination with secondary optical elements, such as waveguides, lenses, or both, for use in the intended application. In fig. 4A, light emitted by the pcLED 100 is collected by a waveguide 402 and directed to a projection lens 404. For example, the projection lens 404 may be a Fresnel lens. Such an arrangement may be suitable for use in, for example, an automotive headlamp. In fig. 4B, the light emitted by the pcLED 100 is directly collected by the projection lens 404 without using an intermediate waveguide. Such an arrangement may be particularly suitable when pcleds can be spaced close enough to each other, and may also be used in automotive headlight and camera flash applications. For example, micro LED display applications may use an optical arrangement similar to that depicted in fig. 4A-4B. In general, any suitable arrangement of optical elements may be used in combination with the pcleds described herein, depending on the desired application.

For many uses of pcLED arrays, it is desirable to divide the light emitted from individual pcleds in the array. That is, it is advantageous to be able to operate individual pcleds in the array as light sources while adjacent pcleds in the array remain dark. This allows for better control of the display or lighting.

In many applications it is also advantageous to place the pcleds close together in an array. For example, a preferred configuration in a micro LED is to have a minimum spacing between individual LEDs. Closely spaced pcleds in an array for use as a camera flash light source or in an automotive headlight may simplify the requirements for any secondary optics and improve the illumination provided by the array.

However, if the pcleds in the array are placed close together, optical crosstalk between adjacent pcleds may occur. That is, light emitted by a pcLED may scatter into or otherwise couple into an adjacent pcLED and appear to originate from another pcLED, thereby preventing the desired division of light.

The possibility of optical cross-talk between pixels in the array prohibits the use of a single shared phosphor layer on top of the LED array. Instead, a patterned phosphor deposition, providing discrete phosphor pixels on each light emitting element, is required, in combination with reflective sidewalls on the phosphor pixels.

If the spacing between the LEDs in the array is small, e.g., less than 10 or 20 microns, it is difficult to form reflective sidewalls on the phosphor pixels using wet chemical or physical deposition methods due to the high aspect ratio of the channels to be filled or coated. The most common scattering layer used as a side coating for LEDs comprises TiO embedded in silicone₂Scattering particles. Another option is a reflective metal layer such as, for example, aluminum or silver. Yet another option is a multilayer Distributed Bragg Reflector (DBR) structure formed from a stack of alternating layers of high and low refractive index materials, which can provide very high reflectivity depending on the design. To ensure that the reflective layer or structure is uniformly coated on the sidewalls of the phosphor pixels, the sidewalls should be accessible. If the aspect ratio of the gap between adjacent phosphor pixels is high, then the non-uniformity of the reflective coating thickness can be expected to result in non-uniform, non-optimal reflective properties.

This specification discloses methods that can be used to fabricate closely spaced phosphor pixel arrays with thin sidewall reflectors. As summarized above, these methods employ a vapor-phase catalyzed combination of a patterned photoresist structure with a condensation-cured silicone system that includes a phosphor.

The temperatures required to cure the silicone or siloxane are typically higher than those required to ensure clean removal of the photoresist, preventing widespread use of photoresist patterning silicones. For example, if the photoresist is subjected to a typical silicone cure temperature of 120 degrees celsius, sufficient cross-linking occurs in the photoresist to prevent clean removal. Alternatively, if a maximum temperature of 90 degrees celsius is used to ensure later cleaning to remove the photoresist, the silicone is not sufficiently cured and partial removal or edge erosion of the silicone structure may occur during the cleaning step.

As seen in fig. 5, a novel low temperature process 500 for patterning silicone using conventional photoresist is described. The process 500 allows for low temperature curing of the silicone in conjunction with photoresist patterning structures and includes a first step 510 of applying a photoresist to a substrate and patterning or removing the photoresist to form the desired structures. In a second step 520, the cavity or region defined after the removal of the photoresist is at least partially filled with a condensation-cured silicone system. In a third step, catalyst 530 is added from the gas phase. This is followed by a silicone condensation curing step 540. The photoresist is then removed in a fifth step 550, either simultaneously with or after the silicone condensation cure 540.

Positive photoresist compounds suitable for use in the low temperature processes described herein may include a photosensitive material that is photodegraded such that a developer will dissolve away the deposited regions exposed to light. In effect, this leaves a coating where the mask is placed (i.e., the film remains on the previously dark portions of the irradiated resist). Positive resists are typically required to be used at low temperatures because they are susceptible to permanent crosslinking (also known as "hard baking") at high temperatures, thereby rendering the resist incapable of being removed later by a stripping bath (typically a mild solvent system).

Condensation-curable silicone resin systems may include curable polysiloxane compositions that can provide acceptable cure rates without significant processing and storage difficulties.

In certain embodiments, the condensation-curable silicone system may include optional organic, inorganic, or organic/inorganic binders and filler materials. In one embodiment, the light activated phosphors, dyes, or nanoparticles may be bonded together by silicone. In other embodiments, the silicone may form an optical structure, including a lens, a light guide, or a refractive element.

The catalyst used for the condensation cure silicone system catalyst may be selected to minimize the generation of species that require removal, and/or should not require high temperature activation to enable curing at relatively low temperatures and/or use of heat sensitive substrates. The compositions may employ catalysts that are relatively non-toxic and relatively stable in solution but cure relatively rapidly upon drying. The catalyst may be effective at relatively low concentrations, and/or at relatively low (or no) humidity conditions. Catalysts which can be used as the gas phase can be used. In one embodiment, the vapor phase cure of the condensation cure silicone system may be performed using a basic (basic or alkaline) catalyst. In one embodiment, a superbase catalyst may be used, such as described by Swier et al in U.S. patent 9688035. In some embodiments, the silicone solid compositions made using the superbase catalyst exhibit enhanced cure rates, improved mechanical strength, and improved thermal stability compared to similar compositions without the superbase catalyst.

The term "superbase" as used herein refers to compounds having a very high basicity, such as lithium diisopropylamide. The term "superbase" also covers bases resulting from the mixing of two (or more) bases, resulting in new basic materials possessing inherently new properties. The term "superbase" does not necessarily mean a base that is thermodynamically and/or kinetically stronger than another base. Instead, in some embodiments, this means creating the alkaline agent by combining the properties of several different bases. The term "superbase" also encompasses any substance with higher absolute proton affinity (APA =245.3 kcal/mole) and intrinsic gas phase basicity (GB =239 kcal/mole) relative to 1, 8-bis- (dimethylamino) -naphthalene.

Non-limiting examples of super bases include organic super bases, organometallic super bases, and inorganic super bases. Organic superbases include, but are not limited to, nitrogen-containing compounds. In some embodiments, the nitrogen-containing compounds also have low nucleophilicity and relatively mild use conditions. Non-limiting examples of nitrogen-containing compounds include phosphazenes, amidines, guanidines, and polycyclic polyamines. Organic superbases also include compounds in which the active metal has been exchanged with a hydrogen on a heteroatom, such as oxygen (labile alkoxide) or nitrogen (metal amide, such as lithium diisopropylamide). In some embodiments, the superbase catalyst is an amidine compound. In some embodiments, the term "superbase" refers to an organic superbase having at least two nitrogen atoms and a pKb of about 0.5 to about 11, as measured in water.

In certain embodiments of the invention, the superbase catalyst is an organic superbase, such as any of the organic superbases described above or known in the art.

In further embodiments, the superbase catalyst comprises:

1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU), (CAS # 6674-22-2).

The amount of superbase catalyst may vary and is not limited. Generally, the amount added by the gas phase is a catalytically effective amount, which may vary depending on the selected superbase and the vapor permeability properties of the siloxane polymer resin. The amount of superbase catalyst is typically measured in parts per million (ppm) in the solid composition. In particular, the catalyst level is calculated with respect to the copolymer solids. The amount of superbase catalyst added to the curable composition may range from 0.1 to 1000 ppm, alternatively from 1 to 500 ppm, or alternatively from 10 to 100 ppm, as based on the polymer resin content (by weight) present in the solid composition.

The silicone material or siloxane may be selected for mechanical stability, low temperature cure properties (e.g., less than 150-120 degrees celsius), and the ability to be catalyzed using a gas phase catalyst. In one embodiment, organosiloxane block copolymers may be used. Organopolysiloxanes comprising D and T units can be used, wherein the D units are predominantly bonded together to form linear blocks having from 10 to 400D units and the T units are predominantly bonded to one another to form branched polymer chains, which are referred to as "non-linear blocks".

Patterned vapor catalyzed silicone or siloxane materials such as those previously described may be used in LED and micro LED packages. The LED package may contain phosphor materials bonded together using vapor catalyzed silicone. In some embodiments, the silicone-bonded phosphor material may form sidewalls that may be coated with a metal, a light reflective material, or a mirror (e.g., a distributed bragg reflector- "DBR mirror").

Phosphors bonded together using vapor-catalyzed silicone may be positioned on a substrate formed of sapphire or silicon carbide, which is capable of supporting an epitaxially grown or deposited n-type layer of semiconductor. A semiconductor p-type layer may be sequentially grown or deposited on the n-type layer to form an active region at the junction between the layers. Semiconductor materials capable of forming high brightness light emitting devices may include, but are not limited to, group III-V semiconductors, particularly binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen, also referred to as ill-nitride materials.

The phosphor may include one or more wavelength converting materials capable of producing white light or other colors of monochromatic light. All or only a portion of the light emitted by the LED may be converted by the wavelength converting material of the phosphor. Unconverted light may be part of the final spectrum of light, although it need not be. Examples of common devices include a blue-emitting LED segment combined with a yellow-emitting phosphor, a blue-emitting LED segment combined with green and red-emitting phosphors, a UV-emitting LED segment combined with blue and yellow-emitting phosphors, and a UV-emitting LED segment combined with blue, green and red-emitting phosphors. The phosphor combined with the silicone may be molded, dispensed, screen printed, sprayed, or laminated.

In one embodiment, the light reflective material may be a metallization layer. In other embodiments, a dielectric mirror or DBR may be used. In some embodiments, the light reflective material may include a thin layer of a binder, such as silicone and light reflective particles. The light reflecting material may also include organic, inorganic, or organic/inorganic binders and filler materials. For example, the organic/inorganic binder and filler may be, for example, titanium oxide (TiO) with embedded reflectivity₂）、SiO₂Or other reflective/scattering particles. The inorganic binder may include a sol-gel (e.g., a sol-gel of TEOS or MTMS) or a liquid glass (e.g., sodium silicate or potassium silicate), also known as water glass. In some embodimentsThe binder may include a filler for adjusting physical properties. The filler may include inorganic nanoparticles, silica, glass particles or fibers, or other materials capable of improving optical or thermal properties. The light reflective material can be applied to the sidewalls by a variety of processes including evaporation deposition (for metals), atomic layer deposition (for DBR mirrors), or molding, dispensing, screen printing, spraying, or laminating (for reflective particles in an adhesive).

In still other embodiments, the primary or secondary optic may be attached or positioned near the silicone-bonded phosphor in the LED package. The optics may include concave or convex lenses, lenslet arrays, graded index lenses, reflectors, scattering elements, beam homogenizers, diffusers, or other light focusing or blurring optics. A protective layer, transparent layer, thermal layer, or other packaging structure may be used as desired for a particular application.

As seen in fig. 6A-6G, a process is described for forming patterned phosphor structures using positive photoresist and vapor-catalyzed silicone containing particulate phosphor. As seen in fig. 6A, structure 600A includes: a substrate 610 supporting a removable positive photoresist 620; and a silicone structure 630 containing optional phosphors, dyes, light activated nanoparticles, fillers, or other materials.

Fig. 6B illustrates the defined structure 600B after removal of the positive photoresist, leaving a free standing column or template (form) of silicone 630, wherein a cavity 622 is defined adjacent to the silicone structure 630. The cavities may include, but are not limited to, holes, channels, regular patterns (such as rectangular layouts, checkerboard layouts, curved or serpentine layouts, or hexagonal layouts).

Fig. 6C illustrates structure 600C after a reflective layer 640 is applied over the top, sidewalls and substrate 610 of the silicone structure. The reflective layer may be a metal, a dielectric mirror, or reflective particles contained in a binder.

Fig. 6D illustrates structure 620D after filling cavity 622 with silicone and optionally phosphors, dyes, light activated nanoparticles, fillers, or other materials. The silicone may be identical to that used in fig. 6A-6C, or other types of silicone systems and phosphors may be used. For example, a high temperature silicone system that does not require steam catalysis may be used with a set of phosphors having different emission properties.

FIG. 6E illustrates structure 600E after the top reflective layer is removed by grinding, polishing, or etching.

Fig. 6F illustrates the structure 600F after flipping and attachment to an LED substrate including an active light emitter. The LED substrate may be a micro LED with micron-scale features and/or millimeter-scale pixels.

Fig. 6G illustrates structure 600G after substrate 610 and the top reflective layer have been removed by conventional release techniques and/or grinding, polishing, or etching. This leaves a vertically reflective coating 640 on the sidewalls between the silicone structures 630, providing optical isolation between the phosphor pixel structures.

Fig. 7 illustrates an intermediate structure 700 corresponding to the processing steps illustrated by fig. 6C. This includes: a checkerboard pattern in which half of the phosphor array is formed and cured; and a reflective layer formed to cover the vapor catalyzed silicone containing the particulate phosphor "islands" 730. The cavities, channels or grooves (gaps) 722 between islands 730 will be filled with additional phosphor that is cured in the next step, and any coated reflective material on the top and bottom surfaces that is removed prior to attaching the phosphor structure to both the LED array and any additional optics.

Light emitting arrays or micro LED arrays such as disclosed herein may support a wide range of applications that benefit from fine-grained intensity, spatial, and temporal control of light distribution. This may include, but is not limited to, precise spatial patterning of light emitted from the block or individual LEDs. Depending on the application, the emitted light may be spectrally distinct, time adaptive, and/or environmentally responsive. In some embodiments, the light emitting array may provide a preprogrammed light distribution in various intensity, spatial, or temporal patterns. The emitted light may be based at least in part on the received sensor data and may be used for optical wireless communication. As described above, the associated optics may be distinct at the single or multiple LED levels. An example lighting array may include a device having a central block of commonly controlled high intensity LEDs and associated common optics, while edge-positioned LEDs may have individual optics. Common applications supported by arrays of light emitting LEDs include video lighting, automotive headlights, architectural and area lighting, street lighting, and information displays.

Programmable light emitting arrays may be used to selectively and adaptively illuminate buildings or areas for improved visual display or reduced illumination costs. In addition, the light emitting array may be used to project a media facade for decorative sports or video effects. In combination with a tracking sensor and/or a camera, selective illumination of the area around the pedestrian may be possible. Spectrally distinct LEDs can be used to tune the color temperature of lighting, as well as support horticulture illumination of specific wavelengths.

Street lighting is an important application that may greatly benefit from the use of programmable light emitting arrays. A single type of light emitting array may be used to simulate various street light types, for example, allowing switching between a linear street light of type I and a semicircular street light of type IV by appropriate activation or deactivation of selected LEDs. In addition, street lighting costs may be reduced by adjusting the beam intensity or distribution depending on environmental conditions or age. For example, when no pedestrian is present, the light intensity and distribution area may be reduced. If the LEDs of the light emitting array are spectrally distinct, the color temperature of the light can be adjusted according to the corresponding day, dusk, or night conditions.

Programmable light emitting LEDs are also well suited to support applications requiring direct or projected displays. For example, automotive headlamps requiring calibration, or warning, emergency, or informational signs, may all be displayed or projected using a light emitting array. This allows, for example, to modify the directionality of the light output from the automobile headlights. If the light emitting array is composed of a large number of LEDs or comprises a suitable dynamic photomask, textual or numerical information may be presented in user-directed positions. Directional arrows or similar indicators may also be provided.

Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and embodiments are intended to be included within the scope of the appended claims. It is also to be understood that other embodiments of the invention may be practiced without specifically disclosed elements/steps herein.