Monolithic multicolor matrix emitter with patterned phosphor layer

Abstract

A lighting device is disclosed, comprising a plurality of light-emitting diodes arranged in an array, a plurality of optical isolation barriers disposed between the light-emitting diodes and optically isolating the light-emitting diodes, and a patterned converter layer disposed on an array surface formed by the light-emitting surfaces of the light-emitting diodes and the upper surfaces of the optical isolation barriers. The patterned converter layer includes a first region having a first converter and a second region having a second converter different from the first converter, the first region and the second region being disposed on different regions of the array surface.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Patent Application No. 17 / 199,171, filed on March 11, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to phosphor converted lighting devices, and more particularly to lighting devices having patterned phosphor converter layers of two or more colors on arrays and microarrays of light emitting diodes, and methods of forming the patterned phosphor converter layers. Background Art

[0004] Semiconductor light emitting diodes and laser diodes (collectively referred to herein as "LEDs") are among the most efficient light sources currently available. The emission spectrum of an LED typically exhibits a single narrow peak at a wavelength determined by the structure of the device and the composition of the semiconductor material from which it is constructed. By appropriately selecting the device structure and material system, an LED can be designed to operate at ultraviolet, visible, or infrared wavelengths.

[0005] The LED may be combined with one or more wavelength converting materials (generally referred to herein as "phosphors") that absorb light emitted by the LED and in response emit light of a longer wavelength. For such phosphor-converted LEDs ("pcLEDs"), the fraction of light emitted by the LED that is absorbed by the phosphor depends on the amount of phosphor material in the optical path of the light emitted by the LED, for example, on the concentration of the phosphor material in a phosphor layer disposed on or around the LED and the thickness of the layer.

[0006] Phosphor-converted LEDs can be designed so that all light emitted by the LED is absorbed by one or more phosphors, in which case the emission from the pcLED is entirely from the phosphors. In this case, for example, the phosphors can be selected to emit light in a narrow spectral region that is not efficiently produced directly by the LED.

[0007] Alternatively, the pcLED can be designed so that only a portion of the light emitted by the LED is absorbed by the phosphor, in which case the emission from the pcLED is a mixture of the light emitted by the LED and the light emitted by the phosphor. By appropriately selecting the LED, phosphor, and phosphor composition, such a pcLED can be designed to emit, for example, white light having a desired color temperature and desired color rendering characteristics.

[0008] Technical and commercial applications of LEDs and pcLEDs include use in displays, matrices, and light engines, including: automotive adaptive headlights, augmented reality (AR) displays, virtual reality (VR) displays, mixed reality (MR) displays, smart glasses, and displays for mobile phones, smart watches, monitors, and televisions, as well as flash lighting for cameras in mobile phones. For example, the backlighting of liquid crystal displays typically employs pcLEDs that include a combination of green and red phosphors. Individual LEDs or pcLEDs in these architectures can have an area of ​​a few square millimeters to a few square micrometers (microLEDs). Summary of the invention

[0009] In one aspect, a lighting device is disclosed, comprising a plurality of light emitting diodes arranged in an array, a plurality of optical isolation barriers disposed between and optically isolating the light emitting diodes, and a patterned converter layer disposed over an array surface formed by light emitting surfaces of the light emitting diodes and upper surfaces of the optical isolation barriers, the patterned converter layer comprising a first region having a first converter and a second region having a second converter different from the first converter, the first region and the second region being disposed over different regions of the array surface. The first region may be disposed over the light emitting surface, and the second region may be disposed over the optical isolation barrier. The first converter may be a phosphor that converts light emitted from a light emitting diode structure into a warm white color, and the second converter may be a phosphor that converts light emitted from the light emitting diode structure into a cooler white color than the first converter. The area of ​​the first region is less than the area of ​​the light emitting surface, and the second region covers portions of the optical isolation barrier and the edge of the light emitting surface. The light emitting surface may have an area of ​​less than 500 μm by 500 μm, the first converter and the second converter may be formed in an alternating pattern over each adjacent light emitting surface, and each light emitting diode structure may be individually addressable. The light emitting diodes may form a segmented monolithic microLED array. The first converter may emit warm white light, and the second converter may emit cool white light.The first converter may emit white light, and the second converter may emit non-white light, such as red light or infrared light.

[0010] In another aspect, a lighting device is disclosed, comprising a plurality of light emitting diodes arranged in an array, each light emitting diode comprising a light emitting surface; and a patterned converter layer disposed over the light emitting surfaces of the light emitting diodes, the patterned converter layer comprising a first region having a first converter and a second region having a second converter different from the first converter, and at least one first region and at least one second region are disposed over each light emitting surface. The first region or the second region or both may cover portions of an optical isolation barrier. The lighting device may further include a first electrical contact configured to activate light emission from a first portion of the light emitting surface and a second electrical contact configured to activate light emission from a second portion of the light emitting surface. The first region of the converter layer may be disposed over the first portion of the light emitting surface, and the second region of the converter layer may be disposed over the second portion of the light emitting surface. The first portion may be a first half of the light emitting surface, and the second portion may be a second half of the light emitting surface adjacent to the first half. The first portion may include a first quarter of the light emitting surface and a second quarter of the light emitting surface in an angle opposite to the first quarter, and the second portion may include a third quarter of the light emitting surface and a fourth quarter of the light emitting surface in another angle opposite to the third quarter and adjacent to the second quarter. The lighting device may include a circuit driver including a mixer connected to a first electrical contact and a second electrical contact, the mixer being configured to receive an input voltage and an input duty cycle and to distribute the input voltage between the first electrical contact and the second electrical contact based on the input duty cycle. The first converter may be a phosphor that converts light emitted from the light emitting diode structure into a warm white color, and the second converter may be a phosphor that converts light emitted from the light emitting diode structure into a cooler white color than the first converter.

[0011] In yet another aspect, a lighting device is disclosed, comprising: a plurality of light emitting diodes, each light emitting diode including a light emitting surface; a plurality of first electrical contacts, each of which is electrically connected to one of the light emitting diodes and configured to activate light emission from a first portion of each light emitting diode; a plurality of second electrical contacts, each of which is electrically connected to one of the light emitting diodes and configured to activate light emission from a second portion of each light emitting diode; and a patterned converter layer disposed over the light emitting surface of the light emitting diodes, the patterned converter layer comprising a plurality of first regions having a first converter and disposed over the first portion of the light emitting diodes, and a plurality of second regions having a second converter different from the first converter and disposed over the second portion of the light emitting diodes. The first portion may be ¾ of the light emitting surface of each light emitting diode, and the second portion may be the remaining ¼ of the light emitting surface of each light emitting diode. For two adjacent light emitting diodes of the plurality of light emitting diodes, the second portion may be adjacent, and the second converter region may cover a portion of an optical isolation barrier formed between the two adjacent light emitting diodes. For four adjacent light emitting diodes of the plurality of light emitting diodes, the second portion may be adjacent, and the second converter region may cover a portion of an optical isolation barrier formed between the four adjacent light emitting diodes. The lighting device may further include a circuit driver including a mixer connected to the first electrical contact and the second electrical contact, the mixer being configured to receive an input voltage and an input duty cycle and to distribute the input voltage between the first electrical contact and the second electrical contact based on the input duty cycle. The first converter may be a phosphor that converts light emitted from the light emitting diode structure into a warm white color, and the second converter may be a phosphor that converts light emitted from the light emitting diode structure into a cooler white color than the first converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic cross-sectional view of an example pcLED is shown.

[0013] Figure 2A and Figure 2B A schematic cross-sectional view and a top view of a pcLED array are shown, respectively. Figure 2C A perspective view of several LEDs of an example pc-miniLED or pc-microLED array monolithically formed on a substrate is shown.

[0014] Figure 3A and Figure 3B A top schematic view and a cross-sectional view, respectively, of another example of a matrix or array of pcLEDs are shown.

[0015] Figure 4A , Figure 4B and Figure 4CA schematic top view, a cross-sectional view, and an enlarged cross-sectional view, respectively, of a lighting device having a patterned converter layer over an array of light emitting diode structures as disclosed herein are shown.

[0016] Figure 5 is a graph showing simulated color variation across pixels as a function of light source comparing a prior art lighting device and a lighting device disclosed herein.

[0017] Fig. 6A and Figure 6B A top schematic view and a cross-sectional view, respectively, of an example embodiment of a lighting device for an adjustable lighting system disclosed herein having a patterned converter layer over an array of light emitting diode structures. Figure 6C Such as Fig. 6A and Figure 6B Simulation of the adjustment range between warm white and cool white in the chromaticity diagram of the lighting device shown in . Fig.6D and Fig. 6E Shows such as Fig. 6A and Figure 6B Simulated color point transitions between adjacent pixels in the adjustable lighting device shown in .

[0018] Fig. 7A and Figure 7B A schematic top view and a cross-sectional view, respectively, are shown of another example embodiment of a lighting device for an adjustable lighting system having a patterned converter layer over an array of light emitting diode structures. Figure 7C Such as Fig. 7A and Figure 7B Color illumination simulation of an enlarged view of the lighting device shown in FIG. Fig.7D and Fig. 7E Such as Fig. 7A and Figure 7B Graph of simulated color points between adjacent pixels of the lighting device shown in .

[0019] Fig. 8A and Figure 8B A schematic top view and a cross-sectional view, respectively, of an example embodiment of a lighting device with a patterned converter layer and with a dual-color pixel arrangement are shown. Figure 8C Shows Fig. 8A and Figure 8B Schematic top view of a two-color pixel of the lighting device shown in , which shows the electrical contacts of the light-emitting diode structure.

[0020] Fig.9A and Fig. 9B A schematic top view and a cross-sectional view, respectively, of another example embodiment of a lighting device having a patterned converter layer and also having a two-color pixel arrangement are shown. Fig. 9C Shows Fig.9Aand Fig. 9B Schematic top view of a two-color pixel of the lighting device shown in , which shows the electrical contacts of the light-emitting diode structure.

[0021] Fig.10 Shown is a circuit diagram of a complementary dual output pixel driver circuit for use in a lighting device as disclosed herein.

[0022] Fig.11A and Fig. 11B A top schematic view and a cross-sectional view, respectively, of another example embodiment of a lighting device having an array of light emitters and a patterned converter layer are shown. Fig. 11C Shows Fig.11A and Fig. 11B Schematic top view of a two-color pixel of the lighting device shown in , which shows the electrical contacts of the light-emitting diode structure. Fig.11D Shows Fig. 11B An enlarged cross-sectional view of a portion of.

[0023] Fig.12 A diagram illustrating an example embodiment of a method for forming a patterned converter layer such as disclosed herein is shown.

[0024] Fig.13A shows a schematic top view of an electronic board on which a pcLED array may be mounted, and Fig. 13B Similarly, the installation Fig.13A The pcLED array on the electronics board.

[0025] Fig.14A A schematic cross-sectional view of a pcLED array arranged relative to a waveguide and projection lens is shown. Fig. 14B shows the difference between the case without waveguide and Fig.14A The arrangement is similar to the arrangement of .

[0026] Fig.15 An example camera flash system is schematically shown.

[0027] Fig.16 An example display (e.g., AR / VR / MR) system is schematically illustrated. DETAILED DESCRIPTION

[0028] The following detailed description should be read with reference to the accompanying drawings, wherein the same reference numerals refer to similar elements throughout the different figures. The drawings, which are not necessarily to scale, depict selective embodiments and are not intended to limit the scope of the invention. The detailed description illustrates the principles of the invention by way of example, not by way of limitation.

[0029] Figure 1An example of an individual pcLED 100 is shown, which includes a light emitting semiconductor diode structure 102 (collectively referred to herein as an "LED") disposed on a substrate 104, and a converter layer 106 disposed on the LED. The light emitting semiconductor diode structure 102 generally includes an active region disposed between an n-type layer and a p-type layer. Application of a suitable forward bias across the semiconductor structure results in light emission from the active region. The wavelength of the emitted light is determined by the composition and structure of the active region.

[0030] For example, the LED may be a Group III nitride LED that emits blue, violet, or ultraviolet light. LEDs formed from any other suitable material system and emitting any other suitable wavelength of light may also be used. Other suitable material systems may include, for example, Group III phosphide materials, Group III arsenide materials, and Group II-IV materials.

[0031] The converter layer 106 includes a converter material (such as a phosphor, an organic dye or quantum dots) that down converts the light emitted by the LED. The choice of converter material depends on the desired optical output from the pcLED.

[0032] Figure 2A and Figure 2B A cross-sectional view and a top view of a matrix or array of pcLEDs are shown, respectively.

[0033] Figure 2A and Figure 2B The array 200 includes a converter layer 106 formed of a plurality of converter layer pixels 211. The converter layer pixels 211 are separated by a grid of optical isolation barriers 220 between the converter layer pixels 211. The optical isolation barriers 220 may extend into the trenches 230 separating the LEDs. Such optical isolation barriers 220 may allow the segmented converter layer 106 to have infinite contrast between adjacent pixels. The converter layer 106 covers a plurality of individual light emitting diode structures 102 (which will be referred to below). Figure 2C ) and contacts 236 for electrically connecting each light emitting diode structure 102. The contacts 236 and the light emitting diode structures 102 may be located on the substrate 204.

[0034] Such an array 200 may include 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 pcLED array may be formed from separate individual pcLEDs. The substrate 204 may optionally include CMOS circuitry for driving the LEDs, and may be formed from any suitable material.

[0035] although Figure 2A and Figure 2BA four-by-four array of sixteen pcLEDs is shown, but such an array may include, for example, tens, hundreds, or thousands of LEDs. The width (e.g., side length) of each LED in the plane of the array may be, for example, less than or equal to 1 millimeter (mm), less than or equal to 500 microns, less than or equal to 100 microns, or less than or equal to 50 microns. The LEDs in such an array may be spaced apart from each other by grooves (sometimes referred to as streets or lanes) 230 having a width in the plane of the array of, for example, hundreds of microns, less than or equal to 100 microns, less than or equal to 50 microns, less than or equal to 10 microns, or less than or equal to 5 microns. Although the example shown shows rectangular pixels arranged in a symmetrical matrix, the pixels and array may have any suitable shape.

[0036] LEDs with a dimension in the plane of the array (eg, a side length) less than or equal to about 50 microns are generally referred to as microLEDs, and an array of such microLEDs may be referred to as a microLED array.

[0037] Although the illustrated examples show rectangular LEDs or pcLEDs arranged in a symmetrical matrix, the LEDs or pcLEDs and arrays may have any suitable shape or arrangement and need not all be of the same shape or size. For example, LEDs or pcLEDs located in the center portion of the array may be larger than LEDs or pcLEDs located in the peripheral portion of the array. Alternatively, LEDs or pcLEDs located in the center portion of the array may be smaller than LEDs or pcLEDs located in the peripheral portion of the array.

[0038] In a pcLED array, all pcLEDs can be configured to emit substantially the same spectrum. Alternatively, the pcLED array can be a multicolor array, where different pcLEDs in the array can be configured to emit different spectra (colors) of light by employing different phosphor compositions. Similarly, in an array of direct emitting LEDs (i.e., without wavelength conversion by a phosphor), all LEDs in the array can be configured to emit substantially the same spectrum, or the array can be a multicolor array that includes LEDs configured to emit different colors of light.

[0039] Individual LEDs or pcLEDs in the array may be individually operable (addressable) and / or may be operable as part of a group or subset of (eg, adjacent) LEDs or pcLEDs in the array.

[0040] An array of LEDs, or portions of such an array, can be formed as a segmented monolithic structure in which individual LED pixels are electrically isolated from each other by trenches, and optionally by insulating material placed within the trenches, but in which the electrically isolated segments are still physically connected to each other by portions of the semiconductor structure. Figure 2C A perspective view of one example of such a segmented monolithic LED structure is shown, which can be used to form an array such as array 200. Individual semiconductor LED devices 102 in array 200 are separated by trenches 230, which are filled to form n-type contacts 234. The monolithic structure is grown or disposed on substrate 204. Each pixel includes a p-type contact 236, a p-GaN semiconductor layer 102b, an active region 102a, and an n-GaN semiconductor layer 102c; layers 102a / 102b / 102c together form a semiconductor LED 102. A converter layer 106 can be deposited on semiconductor layer 102c (or other intervening layers as applicable). A passivation layer 232 can be formed within trenches 230 to separate at least a portion of n-type contact 234 from one or more layers of semiconductor. As described above, the n-contact 234 , other materials within the trench 230 , or a material different than the material within the trench 230 may extend into the converter layer 106 to form a complete or partial optical isolation barrier 220 between pixels.

[0041] Each LED in the LED array can be individually addressable, can be addressable as part of a group or subset of pixels in the array, or can be non-addressable. Therefore, for any application that requires or benefits from fine-grained intensity, spatial and temporal control of light distribution, the luminous pixel array is useful. These applications may include, but are not limited to, precise special patterning of the emitted light from a pixel block or individual pixels. Depending on the application, the emitted light can be spectrally distinct, adaptive over time, and / or environmentally responsive. Such a luminous pixel array can provide pre-programmed light distribution with various intensity, space, or time patterns. The emitted light can be based at least in part on received sensor data and can be used for optical wireless communication. The associated electronic devices and optical devices can be distinct at the pixel, pixel block, or device level.

[0042] Figure 3A and Figure 3B A top view and a cross-sectional view, respectively, are shown of another example of a matrix or array of pcLEDs.

[0043] Figure 3A and Figure 3B The array 300 includes a plurality of individual LED structures 302 and contacts 336 for electrically connecting to each LED structure 302. The contacts 336 and the LED structures 302 may be located on a substrate 304. Each LED 302 is separated by a trench filled with an optical isolation material to form an optical isolation barrier 330. The structure of the LEDs 302, the contacts 336, and the trenches may be similar to that of the reference Figure 2CHowever, in array 300, the converter layer 306 is not divided by optical barriers, but forms a single blanket layer over the LEDs. Figure 3A In the top view of FIG. 3 , the dashed boxes represent light-emitting diodes disposed below the blanket converter layer 306 .

[0044] Disclosed herein is a light emitting device having a converter layer comprising a pattern of two different converter materials disposed on the same plane on a multi-pixel array light emitting diode, such as the above Figure 2C As shown in , each individual pixel is addressable, and a method for forming such a patterned converter layer is disclosed. As disclosed herein, a lighting device having such a patterned multicolor converter layer on an LED array can be used to solve various problems of prior art lighting devices.

[0045] In prior art light emitting arrays, converter layers 106 and 306 are formed of a single color converter material. That is, the same color converter material (such as the same color phosphor) is used in each converter layer pixel 211 in an array such as array 200, and the blanket layer converter 306 shown in array 300 is also a single color converter material.

[0046] Both arrays 200, 300 have the problem of providing a uniform light source. Both arrays 200 and 300 have optical isolation barriers 220, 330 between each light emitting diode 102, 302, which optically isolate the light emitters. In array 200, the optical isolation barrier 220 further isolates the emitted light. This optical isolation results in dark gaps visible in the light projected from the arrays 200, 300, which may appear as grid lines. In the case of array 300 with a blanket converter layer 306 without the optical isolation barrier 220, the dark gaps may not appear darker than the dark gaps from array 300, but the optical isolation barriers 330 separating the light emitting diodes 302 still reduce the uniformity of the projected light from the array 300. Traditionally, in order to remove these dark gaps from the projected light, a diffuser or system-level lens must be added to the device to compensate for these lines.

[0047] Another cause of unevenly projected light from the arrays 200, 300 is the color variations with angle and the color variations with the light source in the color of the emitted light. That is, some of the light emitted from the light emitters 102, 302 propagates in a direction perpendicular or mostly perpendicular to the surface of the light emitters and passes directly through the converter layer. On the other hand, some of the light emitted from the light emitters 102, 302 propagates more laterally through the layer before leaving the converter layer. Light that propagates laterally has a larger optical pathway and, therefore, can be more down-converted and "warmer" than light emitted more perpendicular to the light emitting surface of the LED. These differences in the optical paths can result in color variations with angle and the color variations with the light source in the light projected from the arrays 200, 300. Traditionally, color mixing is achieved by using secondary optics including a diffuser to obtain a uniform appearance of light.

[0048] A patterned converter layer, which comprises two or more different converters arranged in a pattern over an array of individually addressable LEDs, can be used to improve the appearance of light projected from a light emitting device, in particular the uniformity of the light.

[0049] Figure 4A , Figure 4B and Figure 4C A top view, a cross-sectional view, and an enlarged cross-sectional view are shown, respectively, of a pcLED array that has improved uniformity of the projected light and can therefore be used without additional diffusers and lenses to remove dark gaps, color variations with angle, and color variations with light source of the projected light. This is achieved by using a pattern of two different color converters within the converter layer.

[0050] Figure 4A , Figure 4B and Figure 4C The array 400 includes a plurality of individual LED structures 402 and contacts 436 for electrically connecting to each LED structure 402. The contacts 436 and the LEDs 402 may be located on a substrate 404. Each LED 402 is separated by an optical isolation barrier 430. The structure of the LEDs 402, the contacts 436, and the optical isolation barrier 430 may be similar to that described in reference to FIG. Figure 3B However, in array 400, upper surface 431 of optical isolation barrier 430 is aligned or substantially aligned with the light emitting surface of light emitting diodes 402, such that the surface is flat or substantially flat, and there is no optical isolation barrier protruding into converter layer 406.

[0051] The converter layer 406 of the array 400 has a first portion or region 407 formed by a first converter 417, and a second region 409 formed by a second converter 419 that is different from the first converter 417. For example, the first converter 417 may be a phosphor or a combination of phosphors that emits a warm white color, and the second converter 419 may be a phosphor or a combination of phosphors that emits a cool white color.

[0052] Both the first region 407 and the second region 409 are formed in the same blanket layer 406 in the same plane. Figure 4A , the squares marked with dashed lines represent the light emitting regions 412 of the light emitting diodes 402 below the converter layer 406, and the grid between the light emitting regions 412 indicates the location of the optical isolation barriers 430. The first regions 407 and the second regions 409 form a grid pattern, wherein the first regions 407 are patterned into squares and are surrounded by the second regions 409 formed in a pattern around those squares.

[0053] The square of the first region 407 is located over the light emitting region 412 of the light emitting diode 402 , and the grid pattern of the second region 409 is located over the optical isolation barrier 430 .

[0054] In one example, if Figure 4A-4C As shown in , the area of ​​each independent square of the first region 407 in the converter layer 406 can be smaller than the area of ​​the light emitting region 412 of the light emitting diode 402 (each independent square is located above the light emitting region 412). In this case, the width of the grid pattern of the second region 409 of the converter layer 406 is wider than the width of the optical isolation barrier 430, and the second region 409 also covers the edge of the light emitting region 412 of the light emitting diode 402. In particular, see Figure 4A , width P represents the width of the light emitting area 412 of the light emitting diode 402, and width T represents the width of the optical isolation barrier 430. Width Cp represents the width of the square of the first area 407 having the first converters 417, and width Ct represents the width of the second area 409 having the second converters 419 between the first areas 407. Figure 4A A converter layer 406 is shown where the width Cp is less than the width P, and the width Ct is greater than the width T. In general, the area of ​​the first region 407 may be 80% to 95% of the area of ​​the light emitting surface 412 of the light emitting diode 402 (the first region 407 is located above the light emitting surface 412). This pattern has the advantage of improving color correction and compensating for misalignment during the formation of the converter layer 406. However, other patterns where the area of ​​the first region 407 is substantially equal to or greater than the light emitting region 412 may be used depending on the application.

[0055] like Figure 4BAs shown in FIG. 4 , the first region 407 and the second region 409 are formed in the same layer in a single plane and meet at a junction 411 without the use of an optical barrier. Figure 4B Bond 411 is shown aligned over the light emitting area of ​​LED 402 , but as described above, depending on the pattern, the bond may be aligned with an edge of LED 402 and optical isolation barrier 430 , or even directly over optical isolation barrier 430 .

[0056] Figure 4C yes Figure 4B An expanded view of the portion 450 shown in outline. Figure 4C 406, and how the first region 407 and the second region 409 improve the uniformity of the light emitted from the array 400. The light emitting diode 402 emits light into the converter layer 406, as shown by the large arrow 480 that passes through the light emitting surface 412 of the light emitting diode 402. The converter material in the converter layer then converts the light or part of the light into a different color or color combination. For example, blue light emitted from the light emitting diode 402 can be converted to light that appears white by a combination of yellow and red phosphor materials in the converter layer 406. Light that has a path through the converter layer 406 that is more perpendicular to the light emitting surface 412 is less converted (such as light represented by arrow 482 and labeled as CW light, i.e., a cooler white) than light that moves more laterally through the converter layer 406. Light that moves more laterally through the converter layer 406 has a longer optical path through the converter layer 406 and can therefore be more converted (such as light represented by arrow 484 labeled WW ray, i.e., a warmer white that is more converted due to the longer path length through the converter layer). In a homogenous converter layer such as converter layer 306 of array 300 in FIG. 3 , such light is more likely to be significantly down-converted and result in color variations with angle and color variations with light source. However, as Figure 4CAs shown in FIG. 4 , light moving laterally through converter layer 406 encounters second region 409. The converters in second region 409 of converter layer 406 are different from the converters in first region 407. For example, the converters in second region 409 may be the same converter material as the converters in first region 407, but may have a lower concentration in second region 409 than in first region 407, such that converter light 484 encounters less converter material to convert the light. Alternatively, the converters in second region 409 may be adjusted to compensate for the additional path length of light ray 484, and, for example, the converters in second region 409 may be a warmer white or a cooler white than the converters in first region 407 to adjust the color. For example, if second region 409 has a cooler white converter, then the warmer white light ray 484 will then encounter the cooler white converter material in region 409, which will adjust the color to match the color of light ray 482, such that the light emitted from second region 409, represented by arrow 486, matches or approaches the same color as light ray 482.

[0057] Figure 5 is a graph showing a curve 510 of simulated color as a function of light source for a prior art array, and a curve 511 for the array 400 disclosed herein. Figure 5 The example in uses a 50 μm thick converter layer on a highly compact emitter array of 220 μm × 220 μm pixels. Figure 5 The x-axis in indicates the distance across the light emitting surface of the light emitting diode, where "0" is the center point of the light emitting surface. Figure 5 The y-axis in indicates one of the color coordinates v' of the light emitted from the array at that location. A flatter curve indicates a more uniform color of the emitted light. Comparing curve 510 with curve 511, it can be seen that the prior art shows a large variation in color across the light emitting diodes at + / -100 μm, and particularly over the optical isolation barrier.

[0058] Light emitting devices with a patterned multicolor converter layer on an array of individually addressable LEDs can also be used to improve tunable lighting systems.

[0059] Lighting devices that provide adjustable light output (e.g., a light output that can be changed between warmer white light and cooler white light) are traditionally formed from separate light emitters that provide two or more different colors of light that are combined in the light output. One problem with conventional devices is that in the combined output light, light from emitters of different colors may still be individually discernible. The use of a multi-converter layer as disclosed herein alleviates this problem and improves the light output from an adjustable lighting device. In the lighting device provided herein, two or more different colors of light are emitted from an array of individually addressable pcLEDs with a patterned converter layer, the array having a small scale so that the different pixels are not visible to a person without further magnification. For example, each light emitting diode can have a light emitting surface area of ​​500 μm by 500 μm or less. For example, for certain flash applications, the light emitting surface area can be 300 μm×300 μm. For other applications, the light emitting surface area can be 200 μm by 200 μm.

[0060] Fig. 6A and Figure 6B A top view and a cross-sectional view are respectively shown of another lighting device in an adjustable lighting system, the other lighting device having a pcLED array and a patterned converter layer using two different converters.

[0061] Fig. 6A and Figure 6B The array 600 includes a plurality of individual LED structures 602 and contacts 636 for electrically connecting to each LED structure 602. The contacts 636 and the LED structures 602 may be located on a substrate 604. Each LED 602 ​​is separated by an optical isolation barrier 630. The structure of the LEDs 602, the contacts 636, and the optical isolation barrier 630 may be similar to that of the reference Figure 3B However, in array 600, upper surface 631 of optical isolation barrier 630 is aligned or substantially aligned with the light emitting surface of LED 602, so the surface is flat or substantially flat, and there is no optical isolation barrier protruding into converter layer 606.

[0062] The converter layer 606 of the array 600 is formed of a first region 607 formed of a first converter 617 and a second region 609 formed of a second converter 619 different from the first converter 617. The first converter 617 can result in the emission of warm white light, for example, the first converter 617 can be formed of a phosphor or a combination of phosphors that emit warm white light in response to light emitted from a blue LED. The second converter 619 can result in the emission of cool white light, for example, the second converter 619 can be formed of a phosphor or a combination of phosphors that emit cool white light in response to light emitted from a blue LED.

[0063] The first regions 607 and the second regions 609 are formed in a checkerboard pattern, wherein the shape and area of ​​each region corresponds to and covers the light emitting surface 612 of the LED structure 602. In the checkerboard pattern, the first regions 607 and the second regions 609 alternate along both the rows and the columns of the array of LED structures 602. The first regions 607 and the second regions 609 are in the same plane parallel to the light emitting surface 612, and the first converter 617 and the second converter 619 meet at the junction 611, which in this example is aligned above the optical isolation barrier 630. Each LED structure 602 covered by the first region 607 of the converter layer 606 may be referred to herein as a "warm white pixel" or "WW pixel" (in Fig. 6A and Figure 6B ” WW” in the figure), and each light emitting diode structure 602 covered by the second region 609 of the converter layer 606 may be referred to herein as a “cold white pixel” or “CW pixel” (indicated as “WW” in the figure). Fig. 6A and Figure 6B indicated as “CW” in the figure).

[0064] In array 600, each light emitting diode 602 is individually addressable, and therefore the color of light emitted from array 600 can be adjusted along the black body axis between warm white and cool white colors, such as Figure 6C as shown in . Figure 6C is a simulation of the adjustment range between warm white and cool white in the chromaticity diagram of array 600. Figure 6C , point 627 represents the CIE 1976 color value of the color emitted by the warm white pixel in array 600, and point 629 represents the CIE color value of the color emitted by the cool white pixel in array 600. Line 655 indicates the range of color values ​​that array 600 can emit when the ratio of light emitted from the warm white and cool white pixels is adjusted. That is, in this example, when the warm white pixel is turned on and the cool white pixel is turned off, the color of the light emitted from array 600 is indicated by point 627. On the other hand, when the cool white pixel is turned on and the warm white pixel is turned off, in this example, the color of the light emitted from array 600 is represented by point 629. By adjusting the ratio of light emitted between the warm white pixel and the cool white pixel, the light emitted from array 600 can have a color along line 655. For reference, curve 656 represents a black body emitter.

[0065] Because the warm white and cool white pixels in array 600 are very small in size, for example, having a light emitting surface of 500 μm×500 μm or less, a human cannot discern individual pixel colors in the light emitted by array 600 (without additional magnification). Fig.6D and Fig. 6EA simulated color point transition between adjacent pixels in a 7 pixel by 7 pixel array (i.e., 7×7 pcLEDs) is shown, where each pcLED has a light emitting surface with an area of ​​200 μm by 200 μm, and the thickness of the converter layer 606 measured perpendicular to the light emitting surface 612 from the light emitting surface 612 of the light emitting diode 602 to the upper surface of the converter layer 606 is 60 μm. The simulations were performed using commercial ray tracing software. Fig.6D shows the value of v' (CIE 1976) across a warm white pixel Px(n), and Fig. 6E The values ​​of u' (CIE 1976) across warm white pixels Px(n) are shown. Fig.6D and Fig. 6E It is shown that there is a color point transition between adjacent pixels in array 600, and the colors of adjacent pixels can be resolved when using converter layer 606 even though there is no optical isolation barrier in converter layer 606. Therefore, there is sufficient optical decoupling between adjacent pixels to make independent color control possible, even if the light at the pixel boundaries is partially mixed. To increase uniform illumination, in addition to having a sufficiently small pixel size, a top diffuser lens can also be used.

[0066] Fig. 7A and Figure 7B A top view and a cross-sectional view are respectively shown of another lighting device in an adjustable lighting system, the other lighting device having a pcLED array and a patterned converter layer using two different converters.

[0067] Refer to above Fig. 6A and Figure 6B Similar to the disclosed array 600, Fig. 7A and Figure 7B The array 700 includes a plurality of individual light emitting diode structures 702 and contacts 736 for electrically connecting to each light emitting diode structure 702. The contacts 736 and the light emitting diode structures 702 may be located on a substrate 704. Each light emitting diode 702 is separated by an optical isolation barrier 730. The structure of the light emitting diodes 702, the contacts 736, and the optical isolation barrier 730 may be similar to that of the reference Figure 3B However, in array 700, upper surface 731 of optical isolation barrier 730 is aligned or substantially aligned with the light emitting surface of light emitting diodes 702, such that the surface is flat or substantially flat, and there is no optical isolation barrier protruding into converter layer 706.

[0068] The transducer layer 706 of the array 700 is formed by a first region 707 formed by a first transducer 717 and a second region 709 formed by a second transducer 719 different from the first transducer 717. Fig. 6A and Figure 6B In the array 600 of the example, the first converter and the second converter are phosphors that produce warm white light and cool white light, respectively, but the two converters in the example array 700 are two different colors. For example, the first converter 717 can cause the emission of red light and can be formed by a phosphor that emits red light in response to light emitted from a blue LED. The second converter 719 can cause the emission of cool white light, for example, the second converter 719 can be formed by a phosphor material that emits cool white light in response to light emitted from a blue LED. In another example, the first converter 717 can cause the emission of infrared (IR) light (having a wavelength, for example, in the range of 800nm ​​to 1000nm).

[0069] The first regions 707 and the second regions 709 form a checkerboard pattern, wherein the shape and area of ​​each region corresponds to and covers the light emitting surface 712 of one of the LED structures 702. In the checkerboard pattern, the first regions 707 and the second regions 709 alternate along both the rows and columns of the array of LED structures 702. The first regions 707 and the second regions 709 are in the same plane, parallel to the light emitting surface 712, and the first converters 717 and the second converters 719 meet at the junction 711, which in this example is aligned above the optical isolation barrier 730. Each LED structure 702 covered by the first region 707 of the converter layer 706 may be referred to herein as a "red pixel" (in Fig. 7A and Figure 7B Each LED 702 covered by the second region 709 of the converter layer 706 may be referred to herein as a “cold white pixel” or “CW pixel” (indicated by “R” in FIG. Fig. 7A and Figure 7B “CW” in the diagram).

[0070] In array 700, each light emitting diode 702 is individually addressable and therefore independently controllable, and therefore the color of the light emitted from array 700 can be changed between two colors. When one group of light emitting diode structures 702 under red pixels are turned on and another group of light emitting diode structures 702 under cool white pixels are turned off, the light emitted from array 700 is red. Conversely, when the opposite group of light emitting diodes 702 under cool white pixels are turned on and the light emitting diode structures 702 under red pixels are turned off, the light emitted from array 700 is white. This type of color-changing array can be made of more than two colors. Similar to array 600 disclosed above, by providing power to pixels in a ratio, array 700 can also be adjusted to a color that is a mixture of red pixels and cool white pixels, or any one color used.

[0071] Figure 7CColor illumination simulation of a magnified view of a 3 pixel x 3 pixel array of 200 μm x 200 μm pixels with a 60 μm thick converter film 706. The converter film 706 has red areas 707 and cool white areas 709 in the checkerboard pattern disclosed above. Figure 7C The simulation in FIG. 1 shows that, under magnified view, there are two different converter regions 707 and 709, with two different colors (red and cool white in this example). Furthermore, although the converter layer is formed without an optical barrier (such as Figure 2B and Figure 2C ), but the method of forming converter layer 706 provides optical separation of the different color pixels, where the two different converters are in the same plane and meet at junction 711. Because the pixels are too small to be visually distinguished, the two colors cannot be distinguished individually.

[0072] Fig.7D and Fig. 7E Further shown is the optical separation of two different converter areas 707 , 709 in the converter layer 706 . Fig.7D and Fig. 7E is a graph of simulated color points between adjacent pixels on a 7 pixel by 7 pixel pcLED array with 200 μm by 200 μm pixels and a 60 μm thick converter layer. Fig.7D The "second coordinate value" of is u', and Fig. 7E The "first coordinate value" of is v'. Therefore, Fig.7D and Fig. 7E The color transition between adjacent pixels is depicted and can be used to estimate how much light mixing there is between pixels. It can be seen that for both the first and second coordinate values, there is a relatively abrupt change in color at the junction (+ / - 100 μm). Therefore, despite not having an optical isolation barrier (such as Figure 2B and Figure 2C ), but there is sufficient optical isolation to prevent light from propagating into adjacent pixels. Figure 7A-7E The lighting device disclosed in the invention can be useful for automotive applications, or, for example, to project traffic signs on roads with their corresponding colors. The use of a first converter emitting red light and a second converter emitting infrared light can further contribute to night vision and optical communication capabilities.

[0073] When color contrast between adjacent pixels is not critical to the application, and some mixing of light between the two colors emitted by the two converters is acceptable, other architectures of the lighting device and patterns of the converter layers can be used that can help maximize the efficiency of the lighting device.

[0074] Figure 8A-8C and Figure 9A-9CA lighting device with improved optical efficiency is shown.

[0075] exist Figure 8B 800 includes a plurality of individual LED structures 842. However, in the array 800, each LED has two electrical contacts 846, 847 for electrically connecting to each LED structure 842. The electrical contacts 846, 847 and the LEDs 842 can be located on the substrate 804. Each LED 842 is separated by an optical isolation barrier 830, which electrically isolates each LED structure 842 in the array 800. In one example, the structure of the LEDs 842, the optical isolation barrier 830, and the contacts 846, 847 can be similar to Figure 3B 2c , except that there are two separate and independent p-type contacts electrically connected to each light emitting diode (layers 102a, 102b, and 102c of FIG. 2c ). Additionally, an upper surface 831 of optical isolation barrier 830 is aligned or substantially aligned with light emitting surface 812 of light emitting diode 842 such that the surface is flat or substantially flat, and there is no optical isolation barrier protruding into converter layer 806.

[0076] The converter layer 806 of the array 800 is formed of a first region 807 formed of a first converter 817 and a second region 809 formed of a second converter 819 different from the first converter 817. The first converter 817 may, for example, result in emission of red light and may be formed of a phosphor that emits red light in response to light emitted from a blue LED. The second converter 819 may, for example, result in emission of cool white light and may, for example, be formed of a phosphor material that emits cool white light in response to light emitted from a blue LED.

[0077] The first regions 807 and the second regions 809 form a checkerboard pattern, and the first regions 807 and the second regions 809 are in the same plane in the converter layer 806. In the checkerboard pattern, the first regions 807 and the second regions 809 alternate along both the rows and the columns of the array of light emitting diode structures 802. Fig. 8A , the light emitting surface 812 of the light emitting diode 842 below the converter layer 806 is indicated by a dotted line. The regions 807, 809 of the converter layer 806 are located on the LEDs 842 of the array 800 so that each light emitting surface 806 is disposed under two regions (a first region 807 and a second region 809). Thus, in the converter layer 806, two separate regions 807, 809 form a shape and area corresponding to and covering the light emitting surface 812 of one of the LEDs 842. The first converter 817 and the second converter 819 meet at the junction 811. As shown in Fig. 8AAs can be seen in FIG. 8 , portions of the bond 811 are aligned over the optical isolation barrier 830, and portions of the bond 811 are over the light emitting surface 812. Each light emitting surface 812 covered by the first region 807 and the second region 809 of the converter layer 806 may be referred to herein as a "dual color pixel."

[0078] Each LED 842 (and therefore each two-color pixel) is electrically connected to two independent electrical contacts 846, 847 (e.g., two independent anodes), which allows the LED structure to receive two different current levels. The active layer of each LED 842 acts as a common cathode for the two independent anodes 846, 847. Figure 8C 8 is a top view of a single two-color pixel showing the light emitting surface 812 and common cathode 843 of the light emitting diode, two electrical connections 846 (also labeled A1) and 847 (also labeled A2) below and connected to the common cathode 843 of the light emitting diode, and the junction 811 between the first and second regions 807 and 809 of the converter layer 806. Using two different current levels, the single two-color pixel can be tuned to a specific color within a specific range in the color space provided by the two converter materials 817, 819. Fig.10 Provides more details on driving two-color pixels.

[0079] Fig.9A and Fig. 9B An array 900 is shown which also has a two-color pixel arrangement, but with four converter layer regions per pixel. Array 900 is also shown with a converter layer comprising warm white and cool white phosphors.

[0080] and Fig. 8A and Figure 8B Like array 800 of FIG. 8 , array 900 includes a plurality of individual LED structures 942 having two independent electrical contacts 946, 947, both of which may be located on substrate 904. Optical isolation barriers 930 separate and electrically isolate each LED structure 942 in array 900, wherein upper surfaces 930 of optical isolation barriers 930 are aligned with light emitting surfaces 912 of LED structures 942. There is no optical isolation barrier protruding into converter layer 906.

[0081] The converter layer 906 of the array 900 is formed of a first region 907 formed of a first converter 917 and a second region 909 formed of a second converter 919 different from the first converter 917. The first converter 917 may, for example, result in the emission of warm white light and may be formed of a phosphor that emits warm white light in response to light emitted from a blue LED. The second converter 919 may, for example, result in the emission of cool white light and may, for example, be formed of a phosphor material that emits cool white light in response to light emitted from a blue LED.

[0082] The first regions 907 and the second regions 909 form a checkerboard pattern, and the first regions 907 and the second regions 909 are in the same plane in the converter layer 906. In the checkerboard pattern, the first regions 907 and the second regions 909 alternate along both the rows and the columns of the array of light emitting diode structures 902. Fig.9A , the light emitting surface 912 of the LED 942 below the converter layer 906 is indicated by a dashed line. The checkerboard pattern of the converter layer 906 is located on the LED structures 942 of the array 900 so that each light emitting surface 912 has a total of four regions, two first regions 907 and two second regions 909. Thus, in the converter layer 906, four separate regions form a shape and area corresponding to and covering the light emitting surface 912 of one LED structure 942. Portions of the bond 911 are aligned over the optical isolation barrier 930, and portions of the bond 911 are over the light emitting surface 944.

[0083] Each light emitting surface 912 covered with two first regions 907 and two second regions 909 of the converter layer 960 may be referred to herein as a "two-color pixel", however, more than two colors may be used to form four regions on each pixel, so the pixel may be considered a four-region pixel. In general, such a four-region pixel may be formed by converters of any two, three, or four colors.

[0084] Similar to array 800, two independent electrical contacts 946, 947 of array 900 allow the LED structure to receive two different current levels. The active layer of each LED 942 acts as a common cathode for two independent anodes 946, 947. Using these two different current levels, a single two-color pixel can be adjusted to a specific white value between a warm white converter and a cool white converter. Fig. 9C 9 is a top view of a single two-color pixel of array 900, showing the light emitting surface 912 and common cathode 943 of the light emitting diode, two electrical contacts 946 (also labeled A1) and 947 (also labeled A2) below and connected to the common cathode 943 of the light emitting diode, and the junction 911 between the first and second regions 907 and 909 of the converter layer 906. Fig. 9C As shown in FIG. 1 , each electrical contact 946, 947 is divided into two parts that are electrically connected together, as represented by a connection 977 connecting the two parts of electrical contact 947 and a connection 976 connecting the two parts of electrical contact 946. Therefore, the two parts of each electrical contact 946, 947 provide current to the light-emitting diode 942 under the two regions each having the same color. That is, the electrical contact 946 provides current for the light-emitting diode 942 to emit light into the two cool white regions 909, and the electrical contact 947 provides current for the light-emitting diode 942 to emit light into the two warm white regions 907.

[0085] Using two different current levels, a single four-region two-color pixel can be tuned to a specific color, for example, from cool white to warm white, within a specific range in the color space provided by the two converters 917, 919. It should be noted that the two-color pixels of arrays 800 and 900 can be formed by any combination of two converters, and the concept can be extended to include three or more colors and three or more independent electrodes for each light emitting diode. Fig.10 Provides more details on driving two-color pixels.

[0086] This two-color pixel arrangement reduces the contrast between pixels, but can significantly improve optical efficiency.

[0087] Fig.10 A complementary dual output pixel driver circuit 1000 is shown for use with array 800 or 900 (and array 1100 of FIG. 11 below). Each dual color pixel is driven by its own driver circuit 1000 and can be considered as a single pixel driven by a common drive current and control signal to establish a target color. Figure 8B , Figure 8C , Fig. 9B and Fig. 9C As shown in FIG. 1 , each light emitting diode 842, 942 has two electrical contacts 846, 847 and 946, 947, which are connected to the Fig.10 1046 and A2.Px(n)1047, respectively. Since the LEDs 842, 942 can be activated using two independent electrodes, different regions of the converter layer 806, 906 can be excited using different levels of current applied to the LEDs in different regions. Thus, a single pixel can be tuned to a specific color within the color space provided by the first converter and the second converter.

[0088] In the driver circuit 1000, a small signal analog multiplier 1010 is connected to a first capacitor 1027 and a second capacitor 1029. Each capacitor is directly connected to one of the two electrical contacts of the light emitting diode. That is, the first capacitor 1027 is directly connected to the electrical contact 1046 of the dual-color pixel light emitting diode 1042, and the second capacitor 1029 is directly connected to the electrical contact 1047 of the dual-color pixel light emitting diode 1042. The first and second electrical contacts 1046, 1047 can be, for example, electrical contacts 846, 847 of the light emitting diode 802 in the array 800, or electrical contacts 946, 947 of the light emitting diode 902 in the array 900. The multiplier 1010 is connected to an amplifier 1012 and receives a voltage Vg from the amplifier 1012. The amplifier 1012 is connected to a power supply 1014 through a resistor 1015 (Rsen) and receives power from the power supply 1014.

[0089] The driver circuit 1000 has two inputs. The first input 1030 allows the user to input Vref, which controls the amount of drive power delivered to the light emitting diode 1002. That is, the first input 1030 is input through the amplifier 1012 to provide Vg to the multiplier 1010. The second input 1032 (color control d) determines which of the two anodes receives power. The second input 1020 sets the duty cycle d. In the multiplier 1010, Vg is multiplied by the duty cycle d to determine how much current flows to one electrical contact 1046 or the other electrical contact 1047. If d=0, all power flows through A2 and reaches the electrode 1047, causing light to be emitted from the light emitting diode to the first area of ​​the converter layer, and the light has the color set by the first converter. If d=1, all power flows through A1 and reaches the electrode 1046, causing light to be emitted from the light emitting diode to the second area of ​​the converter layer, and the light has the color set by the second converter. If d is set to a value between 0 and 1, the amount of power sent to the first and second electrodes is set proportionally, resulting in a mix of light emitted by the first converter and the second converter that is proportional to the amount of power supplied to the respective electrodes. That is, a multiplier 1010 is employed to balance the set drive current through each light emitting diode such that I(1ed.color1(1046))=d*ldrv and I(1ed.color2(1047))=(1-d)*ldrv, where ldrv is the set drive current of the current source and d can vary between 0 and 1. This allows for adjustment functionality and control of the color point of a dual color pixel. This allows for control of both power and color point. This arrangement can significantly simplify the complexity of the drive and / or reduce the number of components and / or improve driver efficiency.

[0090] Patterned converter layers that improve the uniformity of light emitted from the array may also be used in dual pixel type arrangements. Figures 11A-11D An array 1100 having a patterned converter layer and pixel arrangement is shown that can emit light with improved color uniformity and reduced dark gap artifacts. Array 1100 also uses a two-color pixel arrangement similar to arrays 800 and 900, but has an uneven number of two converters. For example, a warmer white converter forms 75% of the converter layer and a cooler white converter forms 25% of the converter layer.

[0091] As with arrays 800 and 900, array 1100 includes a plurality of individual LED structures 1142 having two independent electrical contacts 1146, 1147, both of which may be located on substrate 1104. Optical isolation barriers 1130 separate and electrically isolate each LED structure 1142 in array 1100, wherein upper surfaces 1131 of optical isolation barriers 1130 are substantially aligned with light emitting surfaces 1112 of LED structures 1142. There are no optical isolation barriers protruding into converter layer 1106.

[0092] The converter layer 1106 of the array 1100 has a first region 1107 formed by a first converter 1117 and a second region 1109 formed by a second converter 1119 that is different from the first converter 1117. The first converter 1117 may, for example, result in emission of white light having a slightly warmer color and may be formed of a phosphor that emits warm white light in response to light emitted from a blue LED. The second converter 1119 may, for example, result in emission of white light having a slightly cooler color and may, for example, be formed of a phosphor material that emits cooler white light in response to light emitted from a blue LED.

[0093] The first region 1107 and the second region 1109 form a grid pattern, wherein the larger area of ​​the first region 1107 surrounds the smaller area of ​​the second region 1109. Fig.11A, the light emitting surface 1112 of the light emitting diode 1142 below the converter layer 1106 is indicated by a dotted line. The pattern of the first region 1107 and the second region 1109 is formed so that a portion of each light emitting surface 1112 is covered by portions of both the first region and the second region. In this example, approximately 75% of the light emitting surface 1112 is covered by the first region 1107 of the converter layer 1106, and approximately 25% (one corner) of the light emitting surface 1112 is covered by the second region 1109. The converter layer 1106 is formed so that the smaller area of ​​the second region 1109 is positioned to cover the intersection 1160 where the four corners of four adjacent light emitting surfaces 1112 meet. The junction 1111 of the first region 1107 and the second region 1109 is located above the optical isolation barrier 1130 and the light emitting surface 1112 to pass through the junction 1130.

[0094] Similar to arrays 800 and 900, two independent electrical contacts 1146, 1147 of array 1100 allow the LED structure to receive two different current levels. Using these two different current levels, a single two-color pixel can be adjusted to a specific white value between a warm white converter and a cool white converter. Fig. 11C 1 is a top view of a single two-color pixel of array 1100, showing the light emitting surface 1112 and common cathode 1143 of the light emitting diode, two electrical contacts 1146 and 1147 below and connected to the light emitting diode, and a portion of the junction 1111 between the first and second regions 1107 and 1109 of the converter layer 1106 above the light emitting surface 1112. The two portions of each electrical contact 1146, 1147 provide current to the common cathode 1143 of the light emitting diode under the first and second regions 1107, 1109, respectively. That is, the electrical contact 1146 provides current to the light emitting diode 1142 to emit light into the warmer white region 1107, and the electrical contact 1147 provides current to the light emitting diode 1142 to emit light into the cooler white region 1109. Using two different current levels, the two-color pixel of array 1100 can be tuned to a specific color within a specific range in the color space provided by the two converter materials 1117, 1119, and in particular can be adjusted to provide a more uniform light source. You can use (for example) Fig.10 The circuit provides current to the two-color pixels of array 1100.

[0095] Fig.11D yes Fig. 11C An expanded view of the portion 1150 shown in outline. Fig.11D1 shows how light emitted from the light emitting diode 1142 propagates through the converter layer 1106, and how the first region 1107 and the second region 1109 improve the uniformity of the light emitted from the array 1100. The light emitting diode 1142 emits light into the converter layer 1106, as shown by the large arrow 1180 that passes through the light emitting surface 1112 of the light emitting diode 1142. The converter material in the converter layer then converts the light or part of the light into a different color or color combination. For example, blue light emitted from the light emitting diode 1142 can be converted to light that appears white by a combination of yellow and red phosphor materials in the converter layer 1106. Light that has a more vertical path through the converter layer 1106 is less converted (such as light represented by arrow 1182 and labeled as CW light, i.e., a cooler white) than light that moves more laterally through the converter layer 1106. Light that moves more laterally through the converter layer 1106 has a longer optical path through the converter layer 1106 and can therefore be more converted (such as light represented by arrow 1184 labeled WW ray, i.e., a warmer white that is more converted due to the longer path length through the converter layer). In a homogenous converter layer such as converter layer 306 of array 300 in FIG. 3 , such light is more likely to be significantly down-converted and result in color variations with angle and color variations with light source. However, as Fig.11DAs shown in FIG. 1 , light moving laterally through the converter layer 1106 encounters the second region 1109. The converters in the second region 1109 of the converter layer 1106 are different from the converters in the first region 1107. For example, the converters in the second region 1109 may be the same converter material as the converters in the first region 1107, but may have a lower concentration in the second region 1109 than in the first region 1107, such that the converter light 1184 encounters less converter material to convert the light. Alternatively, the converters in the second region 1109 may be adjusted to compensate for the additional path length of the light ray 1184, and, for example, the converters in the second region 1109 may be a warmer white or a cooler white than the converters in the first region 1107 to adjust the color. For example, if the second region 1109 has a cooler white converter, the warmer white light ray 1148 will then encounter the cooler white converter material in the region 1109, which will adjust the color to match the color of the light ray 1182, such that the light emitted from the second region 1109, represented by arrow 1186, matches or is close to the same color as the light ray 1182. The light emitted from the second region 1109, represented by arrows 1186, thus also has a cooler white color. In addition, for each light emitting diode 1142, the amount of light emitted into the first region 1107 and the second region 1109 can be controlled by two different electrical contacts 1146, 1147 under each region, respectively. Therefore, by adjusting the ratio of light from the light emitting diode 1142 entering each of the two regions 1107, 1109, the uniformity of the light emitted by the array 1100 can be further improved.

[0096] This dual-color pixel arrangement of array 1100 reduces the contrast between pixels, but can significantly improve optical efficiency. Color mixing improves as the pixel size decreases, for example, to a size of a few microns. The pixel size can, for example, drop from 20-50μm×20-50μm to, for example, 2-5μm×2-5μm. When the pixel size is significantly larger than the size of the converter (e.g., the phosphor particle size), the dual-color pixel has improved performance. When quantum dots are used as converters, the quantum dots are so small that they can be deposited in relatively large quantities even if the pixel size is only 2-5μm×2-5μm.

[0097] Fig.12A method for forming a patterned converter layer (such as the patterned converter layer disclosed herein) is shown. At S1210, a photoresist pattern is formed directly onto a light-emitting diode structure or onto a carrier substrate. As will be appreciated by one of ordinary skill in the art, a positive or negative photoresist may be used. After applying and developing the photoresist pattern, a first converter mixture is applied. The first converter mixture may include a first converter material, such as a phosphor, an organic dye, or a quantum dot, dispersed in a binder such as a silicone. The first converter mixture may be applied to the photoresist pattern using, for example, blade coating or slot coating, which may leave an excess of the first converter mixture. At S1230, the first converter mixture is cured or partially cured, and the excess amount may then be removed, for example, by a planarization process (S1240). The selected photoresist should be compatible with the curing process of the first converter mixture. At S1250, after removing the excess first converter material, the photoresist may be stripped, for example by plasma ashing, or by wet chemical stripping in the case of a positive photoresist. Removing the photoresist leaves a gap in the converter layer around the cured or partially cured first converter mixture, which will be filled by the second converter. At S1260, the second converter mixture is applied using, for example, blade coating or slot coating, which may leave excess second converter mixture. The second converter mixture may include a second converter material, such as a phosphor, an organic dye, or a quantum dot, dispersed in a binder such as silicone. After application, the second converter material fills the gap in the converter layer surrounding the cured first converter mixture left by removing the photoresist. At S1270, the second converter mixture is cured, and, if the first converter mixture was only partially cured at S1230, the curing process of the first converter mixture is complete. In addition, if desired, any remaining excess second converter mixture can be removed, for example, by planarization.

[0098] like Figure 13A-13B As shown in FIG. 1 , an LED or pcLED array 1301 can be mounted on an electronic board 1300 that includes a power and control module 1302, a sensor module 1304, and an attachment area 1306. The power and control module 1302 can receive power and control signals from an external source and signals from the sensor module 1304, and the power and control module 1302 controls the operation of the LED / pcLED based on these signals. The sensor module 1304 can receive signals from any suitable sensor (e.g., from a temperature or light sensor). Alternatively, the array 1301 can be mounted on a board (not shown) separate from the power and control module and the sensor module.

[0099] Each LED or pcLED may optionally be combined or arranged in combination with a lens or other optical element positioned adjacent to or disposed on the converter layer. Such optical elements, not shown in the figures, may be referred to as "primary optical elements". Figure 14A-14B As shown in , an LED array (e.g., mounted on an electronic board 1403) can be arranged in combination with a secondary optical element (such as a waveguide, a lens, or both) for use in an intended application. Fig.14A In FIG. 1 , light emitted by pcLED 1401 is collected by waveguide 1402 and directed to projection lens 1404. For example, projection lens 1404 may be a Fresnel lens. This arrangement may be suitable for use, for example, in motor vehicle headlights or fog lights. Fig. 14B In the embodiment of FIG. 1 , light emitted by pcLED 1401 is collected directly by projection lens 1404 without the use of an intervening waveguide. This arrangement may be particularly suitable when the LEDs or pcLEDs can be spaced sufficiently close to each other, and may also be used in automotive headlights and camera flash applications. For example, microLED display applications may use a method similar to Figure 14A-14B An optical arrangement of the optical arrangement depicted in .

[0100] In another example arrangement, a central block of LEDs or pcLEDs in an array may be associated with a single common (shared) optic, and edge LEDs or pcLEDs in the array located at the periphery of the central block are each associated with a corresponding individual optic. In general, any suitable arrangement of optical elements may be used in combination with the LED and pcLED arrays described herein, depending on the desired application.

[0101] LED and pcLED arrays as described herein can be used in applications that require or benefit from fine-grained intensity, spatial, and temporal control of light distribution. These applications can include, but are not limited to, precise special patterning of light emitted from individual LEDs or pcLEDs or from groups (e.g., blocks) of LEDs or pcLEDs. Depending on the application, the emitted light can be spectrally distinct, adaptive over time, and / or environmentally responsive. Such arrays can provide pre-programmed light distributions in various intensity, spatial, or temporal patterns. The emitted light can be based at least in part on received sensor data and can be used for optical wireless communications. The associated electronics and optics can be distinct at the individual LED / pcLED, group, or device level.

[0102] Independently operable LED or pcLED arrays can be used in conjunction with lenses, lens systems, or other optical devices or optical systems (e.g., as described above) to provide lighting suitable for a particular purpose. For example, in operation, such an adaptive lighting system can provide lighting that varies with color and / or intensity across the illuminated scene or object, and / or is aimed in a desired direction. The beam focusing or manipulation of the light emitted by the LED or pcLED array can be performed electronically by activating the LED or pcLED in groups of different sizes or in sequence to allow dynamic adjustment of the beam shape and / or direction without moving the optical device or changing the focus of the lens in the lighting device. The controller can be configured to receive data indicating the position and color characteristics of an object or person in the scene, and based on this information, control the LED or pcLED in the array to provide lighting suitable for the scene. Such data can be provided by, for example, an image sensor, an optical (e.g., laser scanning) sensor, or a non-optical (e.g., millimeter wave radar) sensor. Such adaptive lighting is increasingly important for automotive vehicles (e.g., adaptive headlights), mobile device cameras (e.g., adaptive flash), VR and AR applications (such as those described below).

[0103] Fig.15 An example camera flash system 1500 is schematically shown including an LED or pcLED array and a lens system 1502, which can be or include an adaptive lighting system as described above, wherein the LEDs or pcLEDs in the array can be individually operable. In operation of the camera flash system, illumination from some or all of the LEDs or pcLEDs in the array and lens system 1502 can be adjusted - deactivated, operated at full intensity, or operated at intermediate intensities. As described above, the array can be a monolithic array, or include one or more monolithic arrays. The use of a multi-color array (e.g., warm white and cool white as described above in FIGS. 6 and 9) allows the flash to be color-adjustable, and further provides greater uniformity of color over angle.

[0104] The flash system 1500 also includes an LED driver 1506 controlled by a controller 1504, such as a microprocessor. The controller 1504 may also be coupled to a camera 1507 and a sensor 1508, and operate according to instructions and profiles stored in a memory 1510. The camera 1507 and the LED or pcLED array and lens system 1502 may be controlled by the controller 1504, for example, to match the illumination provided by the system 1502 (i.e., the field of view of the illumination system) to the field of view of the camera 1507, or otherwise adapt the illumination provided by the system 1502 to the scene viewed by the camera as described above. The sensor 1508 may include, for example, a position sensor (e.g., a gyroscope and / or accelerometer) and / or other sensors that may be used to determine the position and orientation of the system 1500.

[0105] Fig.16 An example display (e.g., AR / VR / MR) system 1600 is schematically shown and includes an array 1610 of individually operable LEDs or pcLEDs, a display 1620, a light array controller 1630, a sensor system 1640, and a system controller 1650. As described above, the array 1610 can be a monolithic array, or include one or more monolithic arrays. The array can be monochrome. Alternatively, the array can be a multi-color array, in which different LEDs or pcLEDs in the array are configured to emit light of different colors, as described above. Thus, the array can be or include a monolithic multi-color matrix of individually operable LED or pcLED light emitters (which can, for example, be microLEDs as described above). For example, a group of three individually operable adjacent LEDs or pcLEDs including a red emitter, a blue emitter, and a green emitter can correspond to a single color-adjustable pixel in a display. For example, Fig.9A Can correspond to four pixels in a display, where each quadrant includes a red converter, a blue converter, a green converter, and an optional CW converter. Other combinations of converters are possible when forming pixels in a display. Array 1610 can be used to project light in a graphic or object pattern that can support AR / VR / MR systems.

[0106] Control inputs are provided to the sensor system 1640, while power and user data inputs are provided to the system controller 1650. In some embodiments, the modules included in the system 1600 may be compactly arranged in a single structure, or one or more elements may be separately mounted and connected via wireless or wired communications. For example, the array 1610, display 1620, and sensor system 1640 may be mounted on a headset or glasses, with the light array controller and / or system controller 1650 mounted separately.

[0107] System 1600 may incorporate a variety of optics (not shown) to couple light emitted by array 1610 into display 1620. Any suitable optics may be used for this purpose.

[0108] Sensor system 1640 may include, for example: external sensors to monitor the environment, such as cameras, depth sensors, or audio sensors; and internal sensors to monitor the position of the AR / VR / MR headset, such as accelerometers or two-axis or three-axis gyroscopes. Other sensors may include, but are not limited to, air pressure, strain sensors, temperature sensors, or any other suitable sensor required for local or remote environmental monitoring. In some embodiments, control inputs may include detected touches or taps, gesture inputs, or controls based on the position of the headset or display.

[0109] In response to data from the sensor system 1640, the system controller 1650 can send images or instructions to the light array controller 1630. Changes or modifications to the images or instructions can also be made through user data input or automatic data input as needed. User data input can include, but is not limited to, data input provided by audio commands, tactile feedback, eye or pupil positioning, or a connected keyboard, mouse, or game controller.

[0110] This disclosure is illustrative, and not limiting. Further modifications will be apparent to those skilled in the art in view of this disclosure, and are intended to fall within the scope of the appended claims.

Claims

1. A light emitting device, comprising: a plurality of light emitting diodes arranged in an array; a plurality of trenches disposed between the light emitting diodes and optically isolating the light emitting diodes; and a patterned converter layer disposed on an array surface formed by the light emitting surfaces of the light emitting diodes and the upper surfaces of the grooves, the patterned converter layer comprising a first region having a first converter and a second region having a second converter configured to emit light of a different color from the first converter, the first region being disposed on and in contact with one of the light emitting surfaces, and the second region being disposed on, in contact with, and covering the entire upper surface of one of the grooves, The area of ​​the first region is smaller than the area of ​​the light emitting surface, and the second region covers portions of the groove and the edge of the light emitting surface. 2 . The light emitting device according to claim 1 , wherein the first converter is a phosphor that converts light emitted from a light emitting diode structure into a warm white color, and the second converter is a phosphor that converts light emitted from a light emitting diode structure into a cooler white color than the first converter.

3. The light emitting device of claim 1, wherein the light emitting surface has an area of ​​less than 500 μm×500 μm, the first converter and the second converter are formed in an alternating pattern over each adjacent light emitting surface, and each light emitting diode structure is individually addressable. The light emitting device according to claim 3 , wherein the first converter emits warm white light and the second converter emits cool white light. The light emitting device according to claim 3 , wherein the first converter emits white light and the second converter emits colored light.

6. A lighting device, comprising: a plurality of light emitting diodes arranged in an array, each light emitting diode comprising a light emitting surface; and a patterned converter layer disposed over and in contact with a light emitting surface of the light emitting diode, the patterned converter layer comprising first regions having first converters and second regions having second converters configured to emit light of a different color than the first converters, and at least one first region and at least one second region being disposed over each light emitting surface, The light emitting diode further comprises a first electrical contact configured to activate light emission from a first portion of the light emitting surface and a second electrical contact configured to activate light emission from a second portion of the light emitting surface. 7 . The lighting device of claim 6 , wherein a first region of the converter layer is arranged over a first portion of the light emitting surface and a second region of the converter layer is arranged over a second portion of the light emitting surface.

8. The lighting device of claim 6, wherein the first portion is a first half of the light emitting surface, and the second portion is a second half of the light emitting surface adjacent to the first half.

9. The lighting device of claim 6, wherein the first portion includes a first quarter of the light emitting surface and a second quarter of the light emitting surface in an angle opposite to the first quarter, and the second portion includes a third quarter of the light emitting surface and a fourth quarter of the light emitting surface in another angle opposite to the third quarter and adjacent to the second quarter.

10. The lighting device of claim 6, further comprising a circuit driver comprising a mixer connected to the first electrical contact and the second electrical contact, the mixer being configured to receive an input voltage and an input duty cycle and to distribute the input voltage between the first electrical contact and the second electrical contact based on the input duty cycle.

11. The lighting device of claim 6, wherein the first converter is a phosphor that converts light emitted from a light emitting diode structure into a warm white color, and the second converter is a phosphor that converts light emitted from a light emitting diode structure into a cooler white color than the first converter.

12. A lighting device, comprising: a plurality of light emitting diodes, each light emitting diode comprising a light emitting surface; a plurality of first electrical contacts, each first electrical contact electrically connected to one of the light emitting diodes and configured to activate emission of a first portion of light from each light emitting diode; a plurality of second electrical contacts, each second electrical contact electrically connected to one of the light emitting diodes and configured to activate emission of light from a second portion of each light emitting diode; as well as A patterned converter layer is disposed over the light emitting surface of the light emitting diode, the patterned converter layer comprising a plurality of first regions having a first converter and disposed over a first portion of the light emitting diode, and a plurality of second regions having a second converter configured to emit light of a different color than the first converter and disposed over a second portion of the light emitting diode. 13 . The lighting device according to claim 12 , wherein the first portion is ¾ of the light emitting surface of each light emitting diode, and the second portion is the remaining ¼ of the light emitting surface of each light emitting diode. 14 . The lighting device of claim 13 , wherein for two adjacent light emitting diodes of the plurality of light emitting diodes, the second portions are adjacent, and the second converter region covers a portion of a trench formed between the two adjacent light emitting diodes. 15 . The lighting device of claim 13 , wherein for four adjacent LEDs of the plurality of LEDs, the second portions are adjacent, and the second converter region covers a portion of a trench formed between the four adjacent LEDs.

16. The lighting device of claim 12, further comprising a circuit driver comprising a mixer connected to the first electrical contact and the second electrical contact, the mixer being configured to receive an input voltage and an input duty cycle and to distribute the input voltage between the first electrical contact and the second electrical contact based on the input duty cycle.

17. The lighting device of claim 12, wherein the first converter is a phosphor that converts light emitted from a light emitting diode structure into a warm white color, and the second converter is a phosphor that converts light emitted from a light emitting diode structure into a cooler white color than the first converter.

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