Lateral heterostructure wavelength conversion layer

Abstract

A lateral hetero wavelength conversion optical element includes a pixel region surrounded by a border region; each region includes down-conversion phosphor particles bound by a coating or a solid medium. The pixel regions are aligned with LEDs in an array. The phosphor regions differ in one or more of composition, particle size, coating thickness, refractive index, or voids (size, number density, or volume fraction). The difference(s) can cause the border region to exhibit greater optical scattering, which can improve contrast of down-converted light emitted by adjacent pixels of the array.

Description

[0001] Priority requirements

[0002] This application claims priority to (i) U.S. Provisional Application No. 63 / 119976, filed December 1, 2020, entitled “Laterally heterogenous conversion layers,” by Bohmer et al., and (ii) U.S. Non-Provisional Application No. 17 / 537919, filed November 30, 2021, entitled “Laterally heterogenous wavelength-converting layer,” by Bohmer et al., each of which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention generally relates to light-emitting diodes and phosphor-converted light-emitting diodes. Background Technology

[0004] Semiconductor light-emitting diodes and laser diodes (collectively referred to as "LEDs" in this document) 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 materials it constitutes. By appropriately selecting the device structure and material system, LEDs can be designed to operate at ultraviolet, visible, or infrared wavelengths.

[0005] LEDs can be combined with one or more wavelength conversion materials (generally referred to herein as "phosphors") that absorb the light emitted by the LED and, in response, emit longer wavelength light. For such phosphor-converting LEDs ("pcLEDs"), the proportion 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 phosphor material in a phosphor layer disposed on or around the LED and the thickness of that layer.

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

[0007] Alternatively, a pcLED can be designed such that only a portion of the light emitted by the LED is absorbed by the phosphor. In this case, the emission from the pcLED is a mixture of light emitted by the LED and light emitted by the phosphor. By appropriately selecting the LED, phosphor, and phosphor components, such a pcLED can be designed to emit white light, for example, with a desired color temperature and desired color rendering properties.

[0008] Multiple LEDs or pcLEDs can be formed together on a single substrate to form an array. Such arrays can be used to form active lighting displays, such as those used in smartphones and smartwatches, computer or video displays, augmented or virtual reality displays, or signage; or to form adaptive lighting sources, such as those used in vehicle headlights, streetlights, camera flash sources, or flashlights (i.e., flashlights). Arrays with one or more individual devices per millimeter (e.g., device spacing or intervals of approximately one millimeter, several hundred micrometers, or less than 100 micrometers, and separations of less than 100 micrometers or only tens of micrometers or less between adjacent devices) are generally referred to as miniLED arrays or microLED arrays (alternatively, μLED arrays). In many instances, such miniLED or microLED arrays may also include phosphor converters as described above; such arrays may be referred to as pc-miniLED arrays or pc-microLED arrays. Summary of the Invention

[0009] A wavelength conversion optical element includes a solid material layer having opposing first and second surfaces and comprising a plurality of discrete pixel regions and intervening boundary regions. The boundary regions at least partially surround each pixel region and at least partially separate each pixel region from adjacent pixel regions.

[0010] For each pixel region, the optical element includes a corresponding plurality of pixel phosphor particles and a transparent pixel adhesive. The pixel adhesive may include: (i) a transparent pixel coating that at least partially coats each pixel phosphor particle and bonds them together within each pixel region while leaving gaps between the bonded pixel phosphor particles; or (ii) a transparent solid pixel medium that substantially fills each pixel region in which the pixel phosphor particles are embedded. In the boundary region, the optical element includes a plurality of boundary phosphor particles and a transparent boundary adhesive. The boundary adhesive may include: (i) a transparent boundary coating that at least partially coats each boundary phosphor particle and bonds them together while leaving gaps between the bonded boundary phosphor particles; or (ii) a transparent solid boundary medium that substantially fills the boundary region in which the boundary phosphor particles are embedded.

[0011] The pixel region differs from the boundary region in one or more of the following ways: (i) characterizing the different sizes, compositions, or refractive indices of the pixel phosphor particles and the boundary phosphor particles; (ii) characterizing the different thicknesses, compositions, or refractive indices of the pixel coating and the boundary coating; (iii) characterizing the different sizes or number densities of the voids between the pixel phosphor particles and the voids between the boundary phosphor particles; or (iv) characterizing the different compositions or refractive indices of the solid pixel medium and the solid boundary medium. Thus, the boundary region may exhibit greater optical scattering of light emitted by either the pixel phosphor particles or the boundary phosphor particles than the pixel region.

[0012] The light-emitting device combines a wavelength-converting optics element with an array of semiconductor light-emitting pixels that emit light of a first wavelength. The spacing of the light-emitting pixels can match the spacing of the pixel regions of the wavelength-converting optics element. Light emitted by the light-emitting pixels enters a first surface of the wavelength-converting optics element and is at least partially absorbed by the pixel phosphor particles and boundary phosphor particles, resulting in the emission of down-converted light of one or more down-converted wavelengths longer than the first wavelength from those phosphor particles. The wavelength-converting optics element can be positioned such that the pixel regions are substantially aligned with the light-emitting pixels of the array. The increased optical scattering exhibited by the boundary regions can improve the contrast between the down-converted light emitted by adjacent pixels.

[0013] The objects and advantages associated with LEDs, pcLEDs, miniLED arrays, pc-miniLED arrays, microLED arrays, and pc-microLED arrays may become clear when referenced to the illustrations in the accompanying drawings and the examples disclosed in the following written description or the appended claims.

[0014] This summary is provided to present a simplified description of selected concepts, which will be further described in the detailed description below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter. Attached Figure Description

[0015] Figure 1 A schematic cross-sectional view of an example pcLED is shown.

[0016] Figure 2A and Figure 2B A schematic cross-sectional view and a top view of a pcLED example array are shown, respectively.

[0017] Figure 3A A schematic cross-sectional view of an example pcLED array relative to the waveguide and projection lens arrangement is shown. Figure 3B It shows the relationship with Figure 3AIt has a similar arrangement, but without waveguides.

[0018] Figure 4A A schematic top view of an example miniLED or microLED array is shown, along with a magnified portion of the array's 3×3 LEDs. Figure 4B A perspective view of several LEDs in an example pc-miniLED or pc-microLED array monolithically formed on a substrate is shown. Figure 4C This is a side cross-sectional schematic diagram of an example of a close-packed array of multicolor phosphor conversion LEDs on a single die and substrate.

[0019] Figure 5A This is a schematic top view of a portion of an example LED display, where each display pixel is a red, green, or blue phosphor-converted LED pixel. Figure 5B This is a schematic top view of a portion of an example LED display, where each display pixel includes multiple phosphor-converting LED pixels (red, green, and blue) integrated onto a single die, which is coupled to a control circuitry backplane.

[0020] Figure 6A A schematic top view of an example electronic board on which a pcLED array can be mounted is shown, and Figure 6B Similarly, installations are shown. Figure 6A An example pcLED array on an electronic board.

[0021] Figure 7 This is a planar schematic diagram of the wavelength conversion optical element of the present invention.

[0022] Figure 8A and Figure 8B This is a schematic side cross-sectional view of an example of the wavelength conversion optical element of the present invention.

[0023] Figure 9A and Figure 9B This is a schematic side cross-sectional view of an example of the wavelength conversion optical element of the present invention.

[0024] Figures 10A-10F The illustration shows an example method for manufacturing the wavelength conversion optical element of the present invention.

[0025] Figures 11A-11F The illustration shows an example method for manufacturing the wavelength conversion optical element of the present invention.

[0026] Figure 12 A schematic side cross-sectional view of an example wavelength conversion optical element located on an array of light-emitting pixels.

[0027] Figure 13This is a simulated data curve showing the brightness versus contrast of a lateral heterogeneous wavelength conversion optical element and a lateral homogeneous wavelength conversion layer.

[0028] The examples depicted are merely illustrative; all features may not be shown in full detail or to the proper scale; for clarity, some features or structures may be exaggerated or reduced relative to others, or omitted entirely; the figures should not be considered to scale unless explicitly indicated otherwise. For example, the vertical dimensions or layer thicknesses of individual LEDs may be exaggerated relative to their lateral extent or relative to the thickness of the substrate or phosphor. The examples shown should not be construed as limiting the scope of this disclosure or the appended claims. Detailed Implementation

[0029] The following detailed description should be read with reference to the accompanying drawings, in which the same reference numerals refer to similar elements throughout the various figures. The drawings, which are not necessarily to scale, depict selective examples 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.

[0030] Figure 1 An example of a standalone pcLED 100 is shown, comprising a semiconductor diode structure 102 (collectively referred to herein as "LED" or "semiconductor LED") disposed on a substrate 104, and a wavelength conversion structure (e.g., a phosphor layer) 106 disposed on the semiconductor LED. The semiconductor diode structure 102 typically includes an active region disposed between an n-type layer and a p-type layer. Applying a suitable forward bias across the diode structure 102 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.

[0031] The LED can be, for example, a group III nitride LED that emits blue, violet, or ultraviolet light. Alternatively, an LED formed from any other suitable material system and emitting light of any other suitable wavelength can be used. Other suitable material systems may include, for example, group III phosphide materials, group III arsenide materials, other binary, ternary, or quaternary alloys of gallium, aluminum, indium, nitrogen, phosphorus, or arsenic, or group II-VI materials.

[0032] Depending on the desired optical output from the pcLED, any suitable phosphor material can be used in or incorporated into the wavelength conversion structure 106.

[0033] Figures 2A-2BCross-sectional and top views of an array 200 of pcLEDs 100 disposed on a substrate 204 are shown, each pcLED 100 including a phosphor pixel 106. Such an array may include any suitable number of pcLEDs arranged in any suitable manner. In the illustrated example, the array is depicted as monolithically formed on a shared substrate; however, alternatively, the pcLED array may be formed from separate individual pcLEDs. The substrate 204 may optionally include traces or interconnects, or CMOS or other circuitry for driving the LEDs, and may be formed from any suitable material.

[0034] Optionally, each pcLED 100 may include a lens or other optical element, or be arranged in combination with a lens or other optical element, said lens or other optical element being positioned adjacent to or disposed on the phosphor layer. Such an optical element (not shown in the figures) may be referred to as a "primary optical element". Additionally, as... Figures 3A-3B As shown, the pcLED array 200 (e.g., mounted on an electronics board) can be arranged in combination with secondary optical elements (such as waveguides, lenses, or both) for use in the intended application. Figure 3A In this arrangement, the light emitted by each pcLED 100 of array 200 is collected by a corresponding waveguide 192 and guided to projection lens 294. For example, projection lens 294 can be a Fresnel lens. This arrangement can be suitable for use in motor vehicle headlights or other adaptive lighting sources. Each pixel may include other primary or secondary optical elements of any suitable type or arrangement, as needed or desired. Figure 3B In this arrangement, the light emitted by the pcLEDs of array 200 is directly collected by projection lens 294 without the use of an intermediate waveguide. This arrangement can be particularly suitable when the pcLEDs can be spaced sufficiently close to each other, and can also be used in automotive headlights, camera flash applications, or other lighting sources. For example, miniLED or microLED display applications can use... Figures 3A-3B The optical arrangement is similar to that described herein. Generally, depending on the desired application, any suitable arrangement of optical elements (primary, secondary, or both) can be used in combination with the pcLED described herein.

[0035] although Figure 2A and Figure 2B A 3×3 array of nine pcLEDs is shown, but such arrays can include, for example, arrays of 10 pcLEDs. 1 10 2 10 3 10 4 or more LEDs, for example, Figure 4AThe diagram illustrates the process. Individual LEDs 100 (i.e., pixels) can have a width w1 (e.g., side length) in the plane of array 200, for example, less than or equal to 1 millimeter (mm), less than or equal to 500 micrometers, less than or equal to 100 micrometers, or less than or equal to 50 micrometers. The LEDs 100 in array 200 can be separated from each other by streets, lanes, or trenches 230 having a width w2 in the plane of array 200, for example, several hundred micrometers, less than or equal to 100 micrometers, less than or equal to 50 micrometers, less than or equal to 20 micrometers, less than or equal to 10 micrometers, or less than or equal to 5 micrometers. The pixel pitch or spacing D1 is the sum of w1 and w2. While the illustrated example shows rectangular pixels arranged in a symmetrical matrix, these pixels and arrays can have any suitable shape or arrangement, whether symmetrical or asymmetrical. Multiple separate LED arrays can be combined in any suitable arrangement in any applicable format to form a larger combined array or display.

[0036] LEDs with a dimension w1 (e.g., side length) less than or equal to about 0.10 mm in the array plane are generally called microLEDs, and an array of such microLEDs can be called a microLED array. LEDs with a dimension w1 (e.g., side length) between about 0.10 mm and about 1.0 mm in the array plane are generally called miniLEDs, and an array of such miniLEDs can be called a miniLED array.

[0037] An array of LEDs, miniLEDs, or microLEDs, or portions thereof, can be formed as a segmented monolithic structure, wherein the individual LED pixels are electrically isolated from each other by trenches and / or insulating materials. Figure 4B A perspective view of an example of such a segmented monolithic LED array 200 is shown. Pixels (i.e., individual semiconductor LED devices 102) in the array are separated by trenches 230 filled to form n-type contacts 234. The monolithic structure is grown or disposed on a 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 the semiconductor LED 102. Wavelength conversion material 106 may be deposited on semiconductor layer 102c (or other applicable intermediate layers). A passivation layer 232 may be formed within the trenches 230 to separate at least a portion of the n-type contacts 234 from one or more layers of the semiconductor. The n-type contact 234, other materials within the trench 230, or materials different from those within the trench 230 may extend into the converter material 106 to form a complete or partial optical isolation barrier 220 between pixels.

[0038] Figure 4C This is a schematic cross-sectional view of a close-packed array 200 of multicolor phosphor-converting LEDs 100 on a monolithic die and substrate 204. The side view shows a GaN LED 102 attached to the substrate 204 via metal interconnects 239 (e.g., gold-to-gold interconnects or solder attached to copper micropillars) and metal interconnects 238. Phosphor pixels 106 are located on or above the corresponding GaN LED pixels 102. The semiconductor LED pixels 102 or phosphor pixels 106 (typically both) may have mirrors or diffuse scattering layers coated on their sides to form an optical isolation barrier 220. In this example, each phosphor pixel 106 is one of three different colors, for example, a red phosphor pixel 106R, a green phosphor pixel 106G, and a blue phosphor pixel 106B (still generally or collectively referred to as phosphor pixels 106). This arrangement allows the LED array 200 to be used as a color display.

[0039] Individual LEDs (pixels) in an LED array can be individually addressable, addressable as part of a group or subset of pixels in the array, or not addressable. Therefore, luminescent pixel arrays are useful for any application that requires or benefits from fine-grained intensity, spatial, and temporal control of light distribution. These applications can include, but are not limited to, precise, specific patterning of emitted light from pixel blocks or individual pixels, and in some instances, forming images as a display device. Depending on the application, the emitted light can be spectrally distinct, time-adaptive, and / or environmentally responsive. Luminescent pixel arrays can provide pre-programmed light distributions with various intensity, spatial, or temporal patterns. The emitted light can be at least partially based on received sensor data and can be used for optical wireless communication. The associated electronics and optics can be distinctly different at the pixel, pixel block, or device level.

[0040] Figure 5A and Figure 5B This is an example of an LED array 200 used in a display application, where the LED display includes a large number of display pixels. In some examples (e.g., such as...) Figure 5A In the example (e.g.), each display pixel includes a single semiconductor LED pixel 102 and a corresponding phosphor pixel 106R, 106G, or 106B of a single color (red, green, or blue). Each display pixel provides only one of the three colors. In some examples (e.g., ...), Figure 5BEach display pixel (in the example shown) comprises a plurality of semiconductor LED pixels 102 and a plurality of corresponding phosphor pixels 106 of a plurality of colors. In the example shown, each display pixel comprises a 3×3 array of semiconductor pixels 102; three of those LED pixels have red phosphor pixels 106R, three have green phosphor pixels 106G, and three have blue phosphor pixels 106B. Therefore, each display pixel can produce any desired color combination. In the example shown, the spatial arrangement of the phosphor pixels 106 of different colors differs among the display pixels; in some examples (not shown), each display pixel may have the same arrangement of phosphor pixels 106 of different colors.

[0041] like Figure 6A and 6B As shown, the pcLED array 200 can be mounted on an electronics board 300, which includes a power and control module 302, a sensor module 304, and an LED attachment area 306. The power and control module 302 can receive power and control signals from an external source and signals from the sensor module 304, based on which it controls the operation of the LEDs. The sensor module 304 can receive signals from any suitable sensor (e.g., a temperature or light sensor). Alternatively, the pcLED array 200 can be mounted on a separate board (not shown) from the power and control module and the sensor module.

[0042] In some instances, reducing pixel size and increasing pixel density can lead to problems. Light emitted by LED pixels or their associated phosphors is emitted in all directions, and in some examples, at an angle distribution approximating a Lambertian distribution. Therefore, as pixel spacing and separation decrease, it can become difficult to prevent light emitted by one LED pixel from overlapping with light emitted by another LED pixel in the pixel array (a phenomenon known as crosstalk), thereby reducing the effective resolution of the LED pixel array or causing unwanted pixel illumination overlap in already illuminated areas. This can be particularly problematic for designs that have separated LED light emitters in the pixel array but still use a single phosphor layer. Figure 4B In the example, the optical isolation barrier 220 formed in the converter material 106 is designed to reduce crosstalk between adjacent pixels in the array. This barrier can take many different forms. In some examples, multiple separated phosphor regions can be used, each associated with a corresponding LED pixel. Separation can be achieved using optical reflective sidewalls, scattering sidewalls, or absorbing sidewalls. In many examples, the wafer-level application and processing of such sidewalls can be difficult and expensive, becoming even more difficult and expensive as pixel spacing and / or separation decreases.

[0043] The wavelength conversion optical element 699 of the present invention includes a phosphor material layer 700 having lateral heterogeneous optical properties, which can be arranged to, for example, at least partially mitigate the crosstalk problem described above. Figure 7 , Figure 8A / Figure 8B and Figure 9A / Figure 9B An example is schematically illustrated. "Lateral" indicates a direction generally parallel to the opposing surfaces 701 and 702 of layer 700 and generally perpendicular to the emitting surfaces of the LED pixels in the LED array employing wavelength-converting optics 699. Material layer 700 includes a plurality of discrete pixel regions 710 and an intermediate boundary region 720; the boundary region 720 at least partially surrounds each pixel region 710 and at least partially separates each pixel region 710 from adjacent pixel regions 710. In some examples, the first and second surfaces 701 and 702 may be substantially flat.

[0044] In each pixel region 710, there are corresponding multiple pixel phosphor particles 712 and transparent pixel adhesive. In some examples (e.g., Figure 8A and Figure 8B The pixel adhesive includes a transparent pixel coating 714 that at least partially coats each pixel phosphor particle 712 and bonds them together within the corresponding pixel region 710; the pixel coating 714 leaves gaps 716 between the bonded pixel phosphor particles 712. In some other examples (e.g., Figure 9A and Figure 9B The pixel adhesive includes a transparent solid pixel medium 718 that substantially fills the corresponding pixel area 710; pixel phosphor particles 712 are embedded within the solid pixel medium 718.

[0045] In some examples, the pixel phosphor particles 712 and the boundary phosphor particles 722 may have the same material composition. In some other examples, the pixel phosphor particles 712 may have a different material composition than the boundary phosphor particles 722; in some such examples, the pixel phosphor particles 712 and the boundary phosphor particles 722 may still exhibit similar optical emission spectra. In some examples, the pixel phosphor particles 712 and the boundary phosphor particles 722 may have the same refractive index. In some other examples, the pixel phosphor particles 712 may have a different refractive index than the boundary phosphor particles 722.

[0046] There are multiple boundary phosphor particles 722 and a transparent boundary binder in the boundary region 720. In some examples (e.g., such as...) Figure 8A and Figure 8BIn the middle, the boundary adhesive includes a transparent boundary coating 724 that at least partially coats each boundary phosphor particle 722 and bonds them together; the boundary coating 724 leaves gaps 726 between the bonded boundary phosphor particles 722. In some other examples (e.g., Figure 9A and Figure 9B The boundary adhesive includes a transparent solid boundary medium 728 that substantially fills the boundary region 720; boundary phosphor particles 722 are embedded within the solid boundary medium 728.

[0047] Pixel region 710 differs from boundary region 720 in one or more of the following aspects: (i) characterizing different sizes, compositions, or refractive indices of pixel phosphor particles 712 and boundary phosphor particles 722; (ii) characterizing different thicknesses, compositions, or refractive indices of pixel coating 714 and boundary coating 724; (iii) characterizing different sizes, number densities, or volume fractions of the voids between pixel phosphor particles 712 and the voids 716 / 726 between boundary phosphor particles 722; or (iv) characterizing different compositions or refractive indices of solid pixel medium 718 and solid boundary medium 728. This difference may result in greater optical scattering (of light emitted by pixel phosphor particles or boundary phosphor particles 712 / 722) exhibited by boundary region 720 than by pixel region 710.

[0048] In some examples (e.g., Figure 8A or Figure 9A Each pixel region 710 and boundary region 720 extend completely through layer 700 from the first surface 701 to the second surface 702. In this arrangement, each pixel region 710 is completely separated from its adjacent pixel region 710 by an intermediate boundary region 720. In other examples (e.g., such as...) Figure 8B or Figure 9B In this arrangement, each pixel region 710 extends completely through layer 700 from the first surface 701 to the second surface 702, but each boundary region 720 extends only partially from the first surface 701 toward the second surface 702. In this arrangement, each pixel region 710 is separated from adjacent pixel regions 710 at the first surface 701, but is adjacent to one or more adjacent pixel regions 710 at the second surface 702.

[0049] In some examples, optical element 699 may include a substrate 698 positioned abutting against a first surface 701 of material layer 700. In some examples, such substrate 698 may include one or more transparent dielectric layers 697, or one or more semiconductor LED layers or structures 696, or both (typically wherein dielectric layer 697 is between optical element 699 and semiconductor LED layer 696). In some instances, layer 700 may be formed directly on substrate 698; in other examples, pre-formed layer 700 may be attached to substrate 698.

[0050] In such Figure 8A or Figure 8B In the examples arranged in the diagram, the pixel adhesive is pixel coating 714, and the boundary adhesive is boundary coating 724. In some of these examples, the boundary phosphor particles 722 may be smaller than the pixel phosphor particles 712. In some examples, the boundary phosphor particles 722 may have a feature size smaller than 30%, 50%, 67%, or 75% of the feature size of the pixel phosphor particles. In some examples, the pixel phosphor particles 712 may have a non-zero feature size smaller than 20 μm, 10 μm, or 5 μm; in some examples, the boundary phosphor particles 722 may have a non-zero feature size smaller than 10 μm, 5 μm, or 2.5 μm. In some examples, the boundary phosphor particles 722 may have a non-zero feature size smaller than 50% of the separation between adjacent pixel regions 710. "Feature size" can be defined in any suitable manner, including D50 (i.e., median particle size), average particle size, maximum particle size, particle size range (defined in any suitable manner), etc.

[0051] In such Figure 8A or Figure 8B In the example arranged in the example, any one or more differences (e.g., feature particle size, material composition, or refractive index) between the pixel phosphor particles 712 and the boundary phosphor particles 722 can lead to an increase in optical scattering of the boundary region 720 relative to the pixel region 710, which in turn can reduce optical crosstalk between adjacent pixel regions 710.

[0052] In such Figure 8A or Figure 8BIn some examples of the arrangement, the boundary coating 724 may be thinner than the pixel coating 714. In some examples, the boundary coating 724 may have a feature thickness less than 30%, 50%, 67%, or 75% of the feature thickness of the pixel coating 724. "Feature thickness" can be defined in any suitable manner, including average thickness, median thickness, minimum or maximum thickness, thickness range (defined in any suitable manner), etc. In examples where the coating thicknesses between the pixel coating 714 and the boundary coating 724 differ, the feature sizes of the phosphor particles 712 and the boundary phosphor particles 722 may also differ, or they may be substantially the same. In examples where the feature sizes of the phosphor particles 712 and the boundary phosphor particles 722 differ from each other, the coating thicknesses between the pixel coating 714 and the boundary coating 724 may also differ, or they may be substantially the same.

[0053] In some examples, the thickness of the pixel coating 714 may be greater than 0.10 μm, greater than 0.20 μm, or greater than 0.30 μm. In some examples, the non-zero thickness of the boundary coating 724 may be less than 0.15 μm, less than 0.10 μm, or less than 0.05 μm.

[0054] In such Figure 8A or Figure 8B In some examples of the arrangement, the pixel region 710 and the boundary region 720 may differ in the size or number density of the voids 716 / 726 (typically, but not necessarily, voids filled with air or gas) left between the bonded phosphor particles 712 / 722 in each region. In some examples, the number density of the voids 716 between the pixel phosphor particles 712 may be less than 30%, 50%, 67%, or 75% of the number density of the voids 726 between the boundary phosphor particles 722. In some examples, the volume fraction of the voids 716 between the pixel phosphor particles 712 may be less than 30%, 50%, 67%, or 75% of the volume fraction of the voids 726 between the boundary phosphor particles 722. In some examples, the feature size of the voids 716 between the pixel phosphor particles 712 may be less than 30%, 50%, 67%, or 75% of the feature size of the voids 726 between the boundary phosphor particles 722. These different number densities, sizes, or volume fractions between voids 716 and 726 may be accompanied by different sizes between phosphor particles 712 and 722, different thicknesses between coatings 714 and 724, or both.

[0055] In such Figure 8A or Figure 8BIn some examples of the arrangement, pixel coating 714 and boundary coating 724 may have the same material composition; in some of these examples, pixel coating 714 and boundary coating 724 may comprise the same single coating material. In some other examples, pixel coating 714 may have a material composition different from that of boundary coating 724; in some of these examples, pixel coating 714 may comprise one or more materials not present in boundary coating 724. In some examples, pixel coating 714 and boundary coating 724 may have the same refractive index; in other examples, pixel coating 714 may have a refractive index different from that of boundary coating 724. In some examples, pixel coating 714 may comprise an inner coating and an outer coating with different corresponding material compositions or refractive indices.

[0056] In some examples, the pixel coating 714 or the boundary coating 724, or both, may comprise one or more metal or semiconductor oxides, including but not limited to any one or more materials such as Al2O3, HfO2, SiO2, Ga2O3, GeO2, SnO2, CrO2, TiO2, Ta2O5, Nb2O5, V2O5, Y2O3, or ZrO2. In some examples, the pixel coating or the boundary coating, or both, may comprise one or more materials compatible with formation using atomic layer deposition (ALD) or conformal chemical vapor deposition (CVD) processes.

[0057] In such Figure 8A or Figure 8B In the example arranged herein, any one or more differences (e.g., feature thickness, material composition, or refractive index) between pixel coating 714 and boundary coating 724 can lead to increased optical scattering of boundary region 720 relative to pixel region 710, which in turn can reduce optical crosstalk between adjacent pixel regions 710. Similarly, any one or more differences (e.g., feature size, number density, or volume fraction) between gap 716 in pixel region 710 and gap 726 in boundary region 720 can lead to increased optical scattering of boundary region 720 relative to pixel region 710, which in turn can reduce optical crosstalk between adjacent pixel regions 710.

[0058] In such Figure 9A or Figure 9B In the example arranged in the diagram, the pixel adhesive is pixel medium 718, and the boundary adhesive is boundary medium 728. Pixel phosphor particles 712 are embedded in pixel medium 718, and boundary phosphor particles 722 are embedded in boundary medium 728. Figure 8A and Figure 8BIn the examples arranged in the diagram, the boundary phosphor particles 722 may have a feature size smaller than 30%, 50%, 67%, or 75% of the feature size of the pixel phosphor particles 712. In some examples, the pixel phosphor particles 712 may have a non-zero feature size smaller than 20 μm, 10 μm, or 5 μm. In some examples, the boundary phosphor particles 722 may have a non-zero feature size smaller than 10 μm, 5 μm, or 2.5 μm. In some examples, the boundary phosphor particles 722 may have a non-zero feature size smaller than 50% of the separation between adjacent pixel regions 710.

[0059] In such Figure 9A or Figure 9B In some examples of the arrangement, the boundary region 720 may also include scattering particles embedded in the boundary medium 728, such as TiO2 or other metal oxide or semiconductor oxide particles.

[0060] In such Figure 9A or Figure 9B In some examples of the arrangement, pixel medium 718 may include one or more polymers, such as one or more silicone resins. In some examples, boundary medium 728 may include one or more polymers, such as one or more silicone resins. In some examples, pixel medium 718 and boundary medium 728 may have the same material composition; in other examples, pixel medium 718 may have a material composition different from that of boundary medium 728. In some examples, pixel medium 718 and boundary medium 728 may have the same refractive index; in other examples, pixel medium 718 may have a refractive index different from that of boundary medium 728.

[0061] In such Figure 9A or Figure 9B In the example arranged herein, any one or more differences (e.g., feature particle size, material composition, or refractive index) between the pixel phosphor particles 712 and the boundary phosphor particles 722 can lead to increased optical scattering of the boundary region 720 relative to the pixel region 710, which in turn can reduce optical crosstalk between adjacent pixel regions 710. Similarly, any one or more differences (e.g., material composition or refractive index) between the pixel medium 718 and the boundary medium 728 can lead to increased optical scattering of the boundary region 720 relative to the pixel region 710, which in turn can reduce optical crosstalk between adjacent pixel regions 710.

[0062] The wavelength conversion optical element of the present invention can be combined with an array 800 of semiconductor light-emitting pixels 810 (e.g., light-emitting diodes (LEDs) 810) that emit light of a first wavelength. Figure 12An example is schematically illustrated. Array 800 can have any suitable type or arrangement (including any of the types or arrangements described above) and can include any suitable or desired number or arrangement of light-emitting pixels 810. The pixels of the array can be monolithically formed on a single semiconductor wafer or can be singulated devices assembled onto an array substrate. Pixel array 800 is positioned such that light emitted by the light-emitting pixels 810 enters a first surface 701 of layer 700 of wavelength conversion optics 699, where at least partially the light is absorbed by pixel phosphor particles 712 and boundary phosphor particles 722. Phosphor particles 712 and 722 then emit down-converted light of one or more down-converted wavelengths longer than a first wavelength. The spacing of the light-emitting pixels 810 substantially matches the spacing of the pixel regions 710 of wavelength conversion optics 699, and wavelength conversion optics 699 is positioned such that its pixel regions 710 are substantially aligned with the light-emitting pixels 810 of array 800; in some instances, some degree of misalignment can be tolerated. In some examples, each luminescent pixel 810 of array 800 may be operable independently of at least one other luminescent pixel 810 of array 800. In some examples, each pixel 810 may be operable independently of all other pixels 810 of array 800.

[0063] In some examples, array 800 can be a miniLED array or a microLED array. In some examples, the spacing between the light-emitting pixels 810 of array 800 can be less than about 1.0 mm, less than about 0.50 mm, less than about 0.33 mm, less than about 0.20 mm, less than about 0.10 mm, less than about 0.08 mm, less than about 0.05 mm, less than about 0.033 mm, or less than about 0.020 mm. Therefore, the spacing between the pixel regions 710 of optical element 699 can also be less than about 1.0 mm, less than about 0.50 mm, less than about 0.33 mm, less than about 0.20 mm, less than about 0.10 mm, less than about 0.08 mm, less than about 0.05 mm, less than about 0.033 mm, or less than about 0.020 mm.

[0064] In many examples, the luminescent pixels 810 are separated by dark (i.e., non-luminescent) pixel boundaries 820 (e.g., trenches, alleys, or channels; in some instances filled with one or more solid materials). The pixel boundaries 820 delineate and separate the array of pixels 810. In some examples, the boundary region 720 of the optical element may be aligned with the pixel boundary 820. In some examples, the non-luminescent pixel boundary 820 may have a non-zero width less than 0.10 mm, less than 0.050 mm, less than 0.033 mm, less than 0.020 mm, less than 0.010 mm, or less than 0.005 mm. In some examples, the boundary region 720 may have a corresponding width equal to the width of the corresponding pixel boundary 820. In some examples, the boundary region 720 may have a corresponding width greater than the width of the corresponding pixel boundary 820. In some examples, the width of the boundary region 720 can be less than 0.10 mm, less than 0.050 mm, less than 0.033 mm, less than 0.020 mm, less than 0.010 mm, less than 0.008 mm, or less than 0.005 mm.

[0065] The boundary region 720 of the optical element 699 can reduce crosstalk between adjacent pixels 810 of the array 800 regarding emitted downconverted light. This reduced crosstalk can be caused by increased optical scattering of the boundary region 720 (as described above) relative to the pixel region 710. In some examples, the pixel region 720 can exhibit a contrast ratio greater than 5:1, greater than 10:1, greater than 20:1, greater than 50:1, greater than 100:1, or greater than 300:1 for downconverted light exiting the second surface 702 of the layer 700 from adjacent pixel regions 720. A lower contrast ratio (e.g., 5:1 or 10:1) may represent an acceptable improvement in arrays with relatively small spacing (e.g., less than 100 μm or less than 50 μm); in arrays with larger spacing, a higher contrast ratio can be expected.

[0066] In some examples, an array of light-emitting pixels 800 used in conjunction with the wavelength conversion optics 699 of the present invention can exhibit overall brightness that changes very little with observed contrast. This contrasts with devices having a laterally homogeneous wavelength conversion layer, which can exhibit a decrease in brightness with increasing contrast. For the same layer except for the presence of the boundary region 720, in Figure 13 The simulation data was plotted in the image.

[0067] In some examples, the first surface 701 of layer 700 of optical element 699 may be positioned against the light-emitting surface of light-emitting pixel array 800. In other examples, one or more transparent dielectric layers may be located between optical element 699 and the light-emitting surface of light-emitting pixel array 800. In such examples, the first surface 701 of material layer 700 of optical element 699 may be positioned against dielectric substrate layer.

[0068] In some examples, array 800 may include an array of semiconductor light-emitting diodes (i.e., LED pixels 810). In some examples, LED pixels 810 may include one or more doped or undoped group III-V, II-VI, or IV semiconductor materials or alloys, or mixtures thereof. In some examples, each LED pixel may include one or more pn junctions, one or more quantum wells, one or more multiple quantum wells, or one or more quantum dots. In some examples, the light emitted by the semiconductor light-emitting pixels may have a vacuum wavelength greater than 0.20 μm, greater than 0.4 μm, greater than 0.8 μm, less than 10 μm, less than 2.5 μm, or less than 1.0 μm.

[0069] Generally, a method of manufacturing a light-emitting device including the optical element 699 of the present invention and the light-emitting array 800 includes positioning the optical element 699 such that a first surface 701 of its material layer 700 faces the light-emitting surface of the light-emitting pixels 810 of the array 800, and wherein the pixel region 710 is substantially aligned with the light-emitting pixel 810. In some examples, the optical element 699 may be positioned directly against the light-emitting surface of the array 800; in other examples, one or more transparent dielectric layers may be located between the optical element 699 and the array 800.

[0070] Material layer 700 can be fabricated in any suitable manner. Typically, this method includes: (i) bonding a plurality of corresponding pixel phosphor particles 712 in each pixel region 720 together with a pixel adhesive; and (ii) bonding a plurality of boundary phosphor particles 722 in a boundary region 720 together with a boundary adhesive. The phosphor particles in pixel regions 710 and boundary regions 720 are also bonded together to form material layer 700.

[0071] In some examples (e.g., in) Figures 10A-10F or Figures 11A-11F In the example sequence), the fabrication method can begin with a selected area of ​​the masking substrate 900 (by spatially selectively forming or depositing mask material 902 in those selected areas, while leaving the remaining areas of the substrate 900 unmasked, which results in...). Figure 10A or Figure 11A(Arrangement). Any suitable spatially selective technique can be used; in some examples, photolithography can be used, with negative or positive photoresist used as needed or desired. Multiple first phosphor particles (or as... Figure 10B and Figure 10C The pixel phosphor particles 712 shown are, or as... Figure 11B and Figure 11C The boundary phosphor particles 722 shown can be deposited onto the unmasked area of ​​the substrate in any suitable manner (e.g., precipitation, blade coating, electrophoretic deposition, etc.). In some instances, no first phosphor particles are deposited on top of the mask material 902 (e.g., Figure 10C or Figure 11C (in the middle); In some other instances, the first phosphor particles may also be deposited on top of the masking material 902 in the masking region (e.g. Figure 10B or Figure 11B In either case, the deposited first phosphor particles are then followed by a first binder (or...) Figure 10B or Figure 10C Pixel adhesive in, or Figure 11B or Figure 11C The boundary adhesive shown in the figure is used to bond them together.

[0072] If the first phosphor particles are deposited on top of the mask material 902 (e.g.) Figure 10B or Figure 11B In the middle), any suitable planarization process (e.g., grinding, polishing, or chemical mechanical polishing (CMP)) can be used to remove the deposited phosphor particles, thereby resulting in... Figure 10C or Figure 11C The arrangement. Once in one of these arrangements, the mask material 902 is then removed by any suitable process, resulting in respectively Figure 10D or Figure 11D The arrangement.

[0073] Next, multiple second phosphor particles (or such as Figure 10E and 10F The boundary phosphor particles 722 shown, or as... Figure 11E and Figure 11F The pixel phosphor particles 712 shown are deposited on the substrate 900, between the deposited, bonded first phosphor particles. Second phosphor particles can be deposited in any suitable manner (e.g., deposition, blade coating, electrophoretic deposition, etc.). In some instances, no second phosphor particles are deposited on top of the bonded first phosphor particles (e.g., ...). Figure 10F or Figure 11F (in the middle); in some other instances, the second phosphor particle may also be deposited on top of the bonded first phosphor particle (e.g. Figure 10E or Figure 11EIn either case, the deposited second phosphor particles are then followed by a second binder (or...). Figure 10E or Figure 10F Boundary adhesive in, or Figure 11E or Figure 11F The pixels (as shown) are bonded together by a second adhesive. A second adhesive further bonds the areas of the first and second phosphor particles together to form material layer 700.

[0074] If no second phosphor particles are deposited onto the bonded first phosphor particles, then... Figure 10F or Figure 11F The arrangement. If some second phosphor particles are deposited on top of the bonded first phosphor particles (e.g. Figure 10E or Figure 11E If desired, those deposited second phosphor particles can be removed using any suitable planarization process (e.g., grinding, polishing, or chemical mechanical polishing (CMP)), thereby resulting in... Figure 10F or Figure 11F The arrangement. However, in some instances, it may be desirable to leave a second phosphor particle covering the first phosphor particle, thereby causing, respectively, Figure 10E or Figure 11E The arrangement.

[0075] exist Figures 10A-10F In the fabrication sequence schematically shown, the masked area of ​​substrate 900 corresponds to boundary region 720, the deposited first phosphor particles are pixel phosphor particles 712, and the first binder is pixel coating 714 (resulting in, for example, Figure 8A The arrangement of the pixels (in the middle) or the pixel medium 718 (causing such as Figure 9A (Arrangement in the middle). After removing the mask material 902, the deposited second phosphor particles are boundary phosphor particles 722, and the second binder is a boundary coating 724 (producing, for example,...). Figure 8A (arrangement in the middle) or boundary medium 728 (generating such as Figure 9A (Arrangement in the middle). If any boundary phosphor particles 722 are adhered to the top of the pixel phosphor particles 712, they can be removed by planarization, thereby producing Figure 8A or Figure 9A The arrangement.

[0076] exist Figures 11A-11F In the fabrication sequence schematically shown, the masked area of ​​substrate 900 corresponds to pixel area 710, the deposited first phosphor particles are boundary phosphor particles 722, and the first binder is a boundary coating 724 (resulting in, for example,...). Figure 8A or Figure 8B Arrangement in the middle) or boundary medium 728 (leading to such as Figure 9A or Figure 9B (Arrangement in the middle). After removing the mask material 902, the deposited second phosphor particles are pixel phosphor particles 712, and the second binder is a pixel coating 714 (producing, for example,...). Figure 8A or Figure 8B (arrangement in the middle) or pixel medium 718 (producing such as Figure 9A or Figure 9B (Arrangement in the middle). If any pixel phosphor particles 712 are adhered to the top of the boundary phosphor particles 722, they can be removed by planarization to produce Figure 8A or Figure 9A The arrangement allows them to remain in place to produce Figure 8B or Figure 9B The arrangement.

[0077] In some examples, one or more atomic layer deposition (ALD) processes or one or more chemical vapor deposition (CVD) processes can be used to form a first binder as a first coating on the first phosphor particles, thereby bonding the first phosphor particles together (e.g., pixel coating 714). Figures 10A-10F The sequence of events binds the pixel phosphor particles 712 together, resulting in Figure 8A or Figure 8B The arrangement; or the boundary coating 724 with Figures 11A-11F The sequence binds the boundary phosphor particles 722 together, thereby causing Figure 8A or Figure 8B (Arrangement). In some examples, the mask material and / or the first coating can be selected such that the coating medium can be formed with reagents or under conditions that do not cause excessive degradation or deformation of the mask material 902. In some examples, a protective layer can be formed on the substrate 900 prior to mask formation, which is less reactive to ALD or CVD reagents than the substrate 900.

[0078] In some examples, one or more ALD processes or one or more CVD processes can be used to form a second binder as a second coating on the second phosphor particles, thereby bonding the second phosphor particles together (e.g., boundary coating 724). Figures 10A-10F The sequence binds the boundary phosphor particles 722 together, thereby causing Figure 8A or Figure 8B The arrangement; or the pixel coating 714 with Figures 11A-11F The sequence of events binds the pixel phosphor particles 712 together, resulting in Figure 8A or Figure 8B (The arrangement). In some examples, the second coating can be formed on the first phosphor particles bonded above the first coating, resulting in a greater thickness of the coating material on the first phosphor particles. For example, in Figures 10A-10FIn the process, the use of ALD or CVD processes to form both the pixel coating 714 and the boundary coating 724 results in a thicker total coating 714 on the pixel phosphor particles 712, and the voids 716 (generated by both the first and second adhesive deposition processes) are smaller and fewer in number compared to the coating 724 and voids 726 (generated only by the second adhesive deposition process) on the boundary phosphor particles 722.

[0079] In some examples, one or more precursors (e.g., monomers, initiators, crosslinking agents, or other polymer precursors) can be deposited and cured to form a first adhesive that serves as a first transparent solid medium for embedding first phosphor particles, thereby bonding the first phosphor particles together (e.g., pixel medium 718). Figures 10A-10F The sequence of events binds the pixel phosphor particles 712 together, resulting in Figure 9A or Figure 9B The arrangement; or the boundary medium 728 Figures 11A-11F The sequence binds the boundary phosphor particles 722 together, thereby causing Figure 9A or Figure 9B (Arrangement). In some examples, the mask material and / or the first solid transparent medium can be selected such that the solid medium can be cured at a temperature or other conditions that do not cause excessive degradation or deformation of the mask material 902. In some examples, one or more precursors (e.g., monomers, initiators, crosslinking agents, or other polymer precursors) can be deposited and cured to form a second adhesive as a second transparent solid medium embedded with the second phosphor particles, thereby bonding the second phosphor particles together (e.g., boundary medium 728). Figures 10A-10F The sequence binds the boundary phosphor particles 722 together, thereby producing Figure 9A or Figure 9B The arrangement; or the pixel medium 718 in Figures 11A-11F The pixel phosphor particles 712 are bonded together in sequence to produce Figure 9A or Figure 9B (Arrangement).

[0080] In some examples, the material layer formed as described above can be removed from substrate 900 and transferred to substrate 698, which may include one or more dielectric layers 697, one or more semiconductor LED layers 696, or both. In some other examples, material layer 700 can be formed on the light-emitting pixel array 800, which serves as substrate 900. In such examples, the material layer can be formed directly on the light-emitting surface of array 800, or on one or more intermediate transparent dielectric layers.

[0081] In addition to the foregoing, the following example embodiments fall within the scope of this disclosure or the appended claims.

[0082] Example 1. A wavelength conversion optical element comprising: (a) a solid material layer having opposing first and second surfaces and including a plurality of discrete pixel regions and an intermediate boundary region, said intermediate boundary region at least partially surrounding each pixel region and at least partially separating each pixel region from adjacent pixel regions; (b) for each pixel region, a plurality of corresponding pixel phosphor particles and a transparent pixel adhesive, said pixel adhesive comprising: or (i) a transparent pixel coating that at least partially coats each pixel phosphor particle and bonds the pixel phosphor particles of the corresponding pixel region together while leaving gaps between the bonded pixel phosphor particles, or (ii) a transparent solid pixel medium that substantially fills the corresponding pixel region in which the pixel phosphor particles are embedded; and (c) in the boundary region, a plurality of boundary phosphor particles. The transparent boundary adhesive comprises: (i) a transparent boundary coating that at least partially coats each boundary phosphor particle and bonds the boundary phosphor particles together while leaving gaps between the bonded boundary phosphor particles; or (ii) a transparent solid boundary medium that substantially fills the boundary region in which the boundary phosphor particles are embedded; or (d) a pixel region that differs from the boundary region in one or more of the following aspects: (i) characterizing different sizes, compositions, or refractive indices of the pixel phosphor particles and the boundary phosphor particles; (ii) characterizing different thicknesses, compositions, or refractive indices of the pixel coating and the boundary coating; (iii) characterizing different sizes, number densities, or volume fractions of the gaps between the pixel phosphor particles and the gaps between the boundary phosphor particles; or (iv) characterizing different compositions or refractive indices of the solid pixel medium and the solid boundary medium.

[0083] Example 2. According to the optical element described in Example 1, the optical scattering of light emitted by the pixel phosphor particles or the boundary phosphor particles in the boundary region is greater than the optical scattering exhibited by the pixel region.

[0084] Example 3. The optical element according to any one of Examples 1 or 2 further includes a substrate positioned against a first surface of the solid material layer.

[0085] Example 4. According to the optical element described in Example 3, the substrate includes one or more transparent dielectric layers.

[0086] Example 5. The optical element according to any one of Examples 3 or 4, wherein the substrate comprises one or more semiconductor LED structures.

[0087] Example 6. In the optical element according to any one of Examples 1 to 5, the feature size of the boundary phosphor particles is less than 30%, 50%, 67%, or 75% of the feature size of the pixel phosphor particles.

[0088] Example 7. The optical element according to any one of Examples 1 to 6, wherein the pixel phosphor particles have a non-zero feature size of less than 20 μm, less than 10 μm, or less than 5 μm.

[0089] Example 8. The optical element according to any one of Examples 1 to 7, wherein the boundary phosphor particles have a non-zero feature size of less than 10 μm, less than 5 μm, or less than 2.5 μm.

[0090] Example 9. In the optical element according to any one of Examples 1 to 8, the boundary phosphor particles have a non-zero feature size that is less than 50% of the separation between adjacent pixel regions.

[0091] Example 10. In the optical element according to any one of Examples 1 to 9, the material composition of the pixel phosphor particles is different from the material composition of the boundary phosphor particles.

[0092] Example 11. In the optical element according to any one of Examples 1 to 9, the pixel phosphor particles and the boundary phosphor particles have the same material composition.

[0093] Example 12. In any one of Examples 1 to 11, the refractive index of the pixel phosphor particles is different from the refractive index of the boundary phosphor particles.

[0094] Example 13. In the optical element according to any one of Examples 1 to 11, the pixel phosphor particles and the boundary phosphor particles have the same refractive index.

[0095] Example 14. In the optical element according to any one of Examples 1 to 13, the characteristic thickness of the boundary coating is less than 30%, 50%, 67%, or 75% of the characteristic thickness of the pixel coating.

[0096] Example 15. In the optical element according to any one of Examples 1 to 14, the number density of the voids between the pixel phosphor particles is less than 30%, 50%, 67%, or 75% of the number density of the voids between the boundary phosphor particles.

[0097] Example 16. In the optical element according to any one of Examples 1 to 15, the volume fraction of the voids between the pixel phosphor particles is less than 30%, 50%, 67%, or 75% of the volume fraction of the voids between the boundary phosphor particles.

[0098] Example 17. In the optical element according to any one of Examples 1 to 16, the characteristic size of the gap between the pixel phosphor particles is less than 30%, 50%, 67%, or 75% of the characteristic size of the gap between the boundary phosphor particles.

[0099] Example 18. In any one of Examples 1 to 17, the refractive index of the pixel coating is different from the refractive index of the boundary coating.

[0100] Example 19. In the optical element according to any one of Examples 1 to 17, the pixel coating and the boundary coating have the same refractive index.

[0101] Example 20. In the optical element according to any one of Examples 1 to 19, the pixel coating and the boundary coating have the same material composition.

[0102] Example 21. In the optical element described in Example 20, the pixel coating and the boundary coating contain the same single coating material.

[0103] Example 22. In any one of Examples 1 to 19, the material composition of the pixel coating differs from that of the boundary coating in the optical element.

[0104] Example 23. According to the optical element of Example 22, the pixel coating comprises one or more materials not present in the boundary coating.

[0105] Example 24. According to the optical element of Example 23, the pixel coating includes an inner coating and an outer coating with different corresponding material compositions or refractive indices.

[0106] Example 25. In any one of Examples 1 to 24, the pixel coating or boundary coating of the optical element comprises one or more metal or semiconductor oxides.

[0107] Example 26. The pixel coating or boundary coating of the optical element according to any one of Examples 1 to 25 comprises any one or more materials including Al2O3, HfO2, SiO2, Ga2O3, GeO2, SnO2, CrO2, TiO2, Ta2O5, Nb2O5, V2O5, Y2O3 or ZrO2.

[0108] Example 27. In any one of Examples 1 to 26, the pixel coating or the boundary coating comprises one or more materials compatible with formation using an atomic layer deposition (ALD) process or a conformal chemical vapor deposition (CVD) process.

[0109] Example 28. The optical element according to any one of Examples 1 to 27, wherein the pixel coating has a thickness greater than 0.10 μm, greater than 0.20 μm, or greater than 0.30 μm.

[0110] Example 29. The optical element according to any one of Examples 1 to 28, wherein the boundary coating has a non-zero thickness of less than 0.15 μm, less than 0.10 μm, or less than 0.05 μm.

[0111] Example 30. In the optical element according to any one of Examples 6 to 13, pixel phosphor particles are embedded in a pixel medium, and boundary phosphor particles are embedded in a boundary medium.

[0112] Example 31. The optical element according to Example 30 further includes scattering particles embedded in the boundary medium.

[0113] Example 32. In the optical element according to Example 31, the scattering particles comprise TiO2 particles.

[0114] Example 33. In the optical element according to any one of Examples 30 to 32, the pixel medium comprises one or more polymers, or the boundary medium comprises one or more polymers.

[0115] Example 34. In the optical element according to Example 33, the pixel medium comprises one or more silicone resins, or the boundary medium comprises one or more silicone resins.

[0116] Example 35. In any one of Examples 30 to 34, the material composition of the pixel medium differs from the material composition of the boundary medium.

[0117] Example 36. In any one of Examples 30 to 35, the pixel medium and the boundary medium have the same material composition.

[0118] Example 37. In any one of Examples 30 to 36, the refractive index of the pixel medium is different from the refractive index of the boundary medium.

[0119] Example 38. In any one of Examples 30 to 36, the pixel medium and the boundary medium have the same refractive index.

[0120] Example 39. In the optical element according to any one of Examples 1 to 38, each pixel region and boundary region extend from a first surface to a second surface such that each pixel region is completely separated from its adjacent pixel regions.

[0121] Example 40. An optical element according to any one of Examples 1 to 38, wherein each pixel region extends from a first surface to a second surface, each boundary region extends only partially from the first surface toward the second surface, each pixel region is separated from an adjacent pixel region at the first surface, and each pixel region is adjacent to one or more adjacent pixel regions at the second surface.

[0122] Example 41. In the optical element according to any one of Examples 1 to 40, the first surface and the second surface are substantially flat.

[0123] Example 42. The optical element according to any one of Examples 1 to 41, wherein the pixel region spacing of the optical element is less than 1.0 mm, less than 0.50 mm, less than 0.33 mm, less than 0.20 mm, less than 0.10 mm, less than 0.08 mm, less than 0.05 mm, less than 0.033 mm, or less than 0.020 mm.

[0124] Example 43. In any one of Examples 1 to 42, the width of the boundary region separating adjacent pixel regions of the optical element is less than 0.10 mm, less than 0.050 mm, less than 0.033 mm, less than 0.020 mm, less than 0.010 mm, less than 0.008 mm, or less than 0.005 mm.

[0125] Example 44. A light-emitting device comprising any one of Examples 1 to 43, the light-emitting device comprising: (A) a wavelength-converting optical element; and (B) a semiconductor light-emitting pixel array emitting light of a first wavelength, the spacing of the light-emitting pixels substantially matching the spacing of the pixel regions of the wavelength-converting optical element, the light-emitting pixel array being positioned such that light emitted by the light-emitting pixels enters a first surface of a material layer of the wavelength-converting optical element and is at least partially absorbed by pixel phosphor particles and boundary phosphor particles, thereby causing down-converted light of one or more down-converted wavelengths longer than the first wavelength to be emitted from those phosphor particles, the wavelength-converting optical element being positioned such that its pixel regions are substantially aligned with the light-emitting pixels of the array.

[0126] Example 45. According to the device described in Example 44, each light-emitting pixel of the array can operate independently of at least one other light-emitting pixel in the array.

[0127] Example 46. The device according to any one of Examples 44 or 45, wherein the pixel region exhibits a contrast ratio greater than 5:1, greater than 10:1, greater than 20:1, greater than 50:1, greater than 100:1, or greater than 300:1 for downconverted light exiting the second surface of the optical element from adjacent pixel regions of the optical element.

[0128] Example 47. In any one of Examples 44 to 46, the first surface of the material layer of the optical element is positioned against the light-emitting surface of the light-emitting pixel array.

[0129] Example 48. The device according to any one of Examples 44 to 47 further includes one or more transparent dielectric layers between the material layer and the light-emitting surface of the light-emitting pixel array, the first surface of the material layer being positioned against the dielectric substrate layer.

[0130] Example 49. In the device according to any one of Examples 44 to 48, the spacing of the light-emitting pixels of the array is equal to the spacing of the pixel regions of the optical element.

[0131] Example 50. According to the device described in Example 49, the spacing of the light-emitting pixels of the array is less than 1.0 mm, less than 0.50 mm, less than 0.33 mm, less than 0.20 mm, less than 0.10 mm, less than 0.08 mm, less than 0.05 mm, less than 0.033 mm, or less than 0.020 mm.

[0132] Example 51. In the device according to any one of Examples 44 to 50, the light-emitting pixels of the array are separated by non-light-emitting pixel boundaries, and the boundary regions of the optical elements are aligned with the pixel boundaries.

[0133] Example 52. According to the device described in Example 51, the non-light-emitting pixel boundary has a non-zero width of less than 0.10 mm, less than 0.050 mm, less than 0.033 mm, less than 0.020 mm, less than 0.010 mm, or less than 0.005 mm.

[0134] Example 53. In the device according to any one of Examples 51 or 52, one or more of the boundary regions have a corresponding width equal to the width of the corresponding pixel boundary.

[0135] Example 54. In any one of Examples 51 to 53, the width of one or more of the boundary regions is greater than the width of the corresponding pixel boundary.

[0136] Example 55. The device according to any one of Examples 44 to 54, wherein the semiconductor light-emitting pixel array comprises a semiconductor light-emitting diode (LED) array.

[0137] Example 56. The device according to any one of Examples 44 to 55, wherein the light-emitting diode comprises one or more doped or undoped group III-V, group II-VI or group IV semiconductor materials or alloys or mixtures thereof.

[0138] Example 57. The device according to any one of Examples 44 to 56, each light-emitting diode includes one or more pn junctions, one or more quantum wells, one or more multiple quantum wells, or one or more quantum dots.

[0139] Example 58. In any one of Examples 44 to 57, the light emitted by the semiconductor light-emitting pixel has a vacuum wavelength greater than 0.20 μm, greater than 0.4 μm, greater than 0.8 μm, less than 10 μm, less than 2.5 μm, or less than 1.0 μm.

[0140] Example 59. A method of manufacturing a device according to any one of Examples 44 to 58, comprising positioning an optical element such that a first surface faces the light-emitting surface of an array of light-emitting pixels.

[0141] Example 60. According to the method described in Example 59, the first surface of the optical element is positioned directly against the light-emitting surface.

[0142] Example 61. According to the method of Example 59, one or more transparent dielectric layers are located between the optical element and the array of light-emitting pixels.

[0143] Example 62. A method of manufacturing an optical element according to any one of Examples 1 to 42, the method comprising: (A) bonding together a plurality of pixel phosphor particles corresponding to each pixel region using a pixel adhesive; and (B) bonding together a plurality of boundary phosphor particles in a boundary region using a boundary adhesive; and (C) bonding together the phosphor particles in the pixel region and the boundary region to form a material layer of the optical element.

[0144] Example 63. A method of manufacturing an optical element according to any one of Examples 1 to 42, comprising: (A) forming a mask on a selected area of ​​a substrate, leaving a remaining area of ​​the substrate unmasked; (B) depositing a plurality of first phosphor particles onto the unmasked area of ​​the substrate and bonding the deposited first phosphor particles together with a first adhesive; (C) removing the mask from the selected area; and (D) depositing a plurality of second phosphor particles onto the substrate between the deposited and bonded plurality of first phosphor particles and bonding the deposited second phosphor particles together with a second adhesive, and bonding the plurality of second phosphor particles to the bonded plurality of first phosphor particles with a second adhesive; and (E) wherein either (i) the first phosphor particles are pixel phosphor particles, the first adhesive is a pixel adhesive, the second phosphor particles are boundary phosphor particles, and the second adhesive is a boundary adhesive, or (ii) the first phosphor particles are boundary phosphor particles, the first adhesive is a boundary adhesive, the second phosphor particles are pixel phosphor particles, and the second adhesive is a pixel adhesive.

[0145] Example 64. According to the method of any one of Examples 62 or 63, the substrate comprises one or more dielectric layers.

[0146] Example 65. According to any one of Examples 62 to 64, the substrate comprises one or more semiconductor layers.

[0147] Example 66. According to the method described in Example 65, the one or more semiconductor layers are arranged as one or more LED structures.

[0148] Example 67. The method according to any one of Examples 62 to 66 further includes removing the optical element from the substrate.

[0149] Example 68. The method according to any one of Examples 62 to 67: (i) using one or more ALD processes or one or more CVD processes to form a first adhesive as a first coating on the first phosphor particles, thereby bonding the first phosphor particles together; or (ii) using one or more ALD processes or one or more CVD processes to form a second adhesive as a second coating on the second phosphor particles, thereby bonding the second phosphor particles together.

[0150] Example 69. According to the method described in Example 68, the second coating is formed on the bonded first phosphor particles over the first coating.

[0151] Example 70. The method according to any one of Examples 68 or 69 further includes forming a protective layer on the substrate prior to forming the mask, the protective layer being less reactive than the substrate relative to one or more reagents used in one or more ALD processes or one or more CVD processes.

[0152] Example 71. A method according to any one of Examples 62 to 67: (i) depositing and curing one or more precursors to form a first adhesive as a first transparent solid medium embedded with first phosphor particles, thereby bonding the first phosphor particles together; or (ii) depositing and curing one or more precursors to form a second adhesive as a second transparent solid medium embedded with second phosphor particles, thereby bonding the second phosphor particles together.

[0153] Example 72. The method according to any one of Examples 63 to 71 further includes removing any first phosphor particles deposited on the mask material from the masked area before removing the mask.

[0154] Example 73. The method according to any one of Examples 63 to 72 further includes removing any second phosphor particles thereon from the deposited, bonded plurality of first phosphor particles.

[0155] Example 74. According to any one of Examples 63 to 72, any second phosphor particles deposited and bonded to the plurality of deposited and bonded first phosphor particles are left in situ, such that the plurality of bonded first phosphor particles are covered by the bonded second phosphor particles.

[0156] This disclosure is illustrative and not restrictive. Further modifications will be apparent to those skilled in the art in light of this disclosure and are intended to fall within the scope of this disclosure or the appended claims. It is intended that equivalents of the disclosed exemplary embodiments and methods, or modifications thereof, should fall within the scope of this disclosure or the appended claims.

[0157] In the foregoing specific embodiments, various features from several example embodiments may be combined for the purpose of streamlining the disclosure. This method of disclosure should not be construed as reflecting an intention that any claimed embodiment requires more features than expressly listed in the corresponding claim. Rather, as reflected in the appended claims, the inventive subject matter may lie in fewer than all features of a single disclosed example embodiment. Therefore, this disclosure should be interpreted as implicitly disclosing any embodiment having any suitable subset of one or more features shown, described, or claimed in this application, including those subsets that may not be expressly disclosed herein. A “suitable” subset of features includes only features that are neither incompatible nor mutually exclusive with any other features relative to that subset. Therefore, the appended claims are thus incorporated into the specific embodiments in their entirety, with each claim itself serving as a separately disclosed embodiment. Furthermore, each of the appended dependent claims should be interpreted as being solely for the purpose of disclosure by incorporating the claims into the specific embodiments, as if written in multiple dependent forms and subordinate to all the foregoing claims that do not contradict them. It should also be noted that the cumulative scope of the appended claims may, but does not necessarily, cover all the subject matter disclosed in this application.

[0158] The following interpretations shall apply to the purposes of this disclosure and the appended claims. Unless expressly stated otherwise, the words “comprising,” “including,” “having,” and variations thereof, wherever they appear, shall be understood as open-ended terms meaning as if a phrase such as “at least” were appended after each instance. The article “a” shall be interpreted as “one or more” unless “only one,” “single,” or other similar limitation is expressly stated or implied in the particular context; similarly, the article “the” shall be interpreted as “one or more of…” unless “only one of…,” “single of…,” or other similar limitation is expressly stated or implied in the particular context. The conjunction “or” shall be interpreted as inclusive unless: (i) it is otherwise expressly stated, for example, by using “or…or…,” “only one of…,” or similar language; or (ii) two or more of the listed alternatives are understood or disclosed (implicitly or explicitly) as incompatible or mutually exclusive in the particular context. In the latter case, “or” will be understood to cover only those combinations involving non-mutually exclusive alternatives. In one example, each of “dog or cat,” “one or more dogs or cats,” and “one or more dogs or cats” will be interpreted as one or more dogs without any cats, or one or more cats without any dogs, or one or more of each. In another example, each of “dog, cat, or mouse,” “one or more dogs, cats, or mice,” and “one or more dogs, cats, or mice” will be interpreted as (i) one or more dogs without any cats or mice, (ii) one or more cats without any dogs or mice, (iii) one or more mice without any dogs or cats, (iv) one or more dogs and one or more cats without any mice, (v) one or more dogs and one or more mice without any cats, (vi) one or more cats and one or more mice without any dogs, or (vii) one or more dogs, one or more cats, and one or more mice. In another example, each of “two or more of dogs, cats or mice” or “two or more dogs, cats or mice” will be interpreted as (i) one or more dogs and one or more cats, without any mice, (ii) one or more dogs and one or more mice, without any cats, (iii) one or more cats and one or more mice, without any dogs, or (iv) one or more dogs, one or more cats, and one or more mice; “three or more”, “four or more”, etc., will be interpreted similarly.

[0159] For the purposes of this disclosure or the appended claims, when enumerating numerical values ​​(with or without terms such as “approximately equal to,” “substantially equal to,” “greater than about,” “less than about,” etc.), standard conventions relating to measurement precision and significant figures shall apply, unless a different interpretation is explicitly stated. For zero quantities described by phrases such as “substantially prevent,” “substantially non-existent,” “substantially eliminated,” “approximately equal to zero,” “negligible,” etc., each such phrase should indicate that the quantity in question has been reduced or diminished to such an extent that, in the context of the intended operation or use of the disclosed or claimed apparatus or method, for practical purposes, the overall behavior or performance of the apparatus or method would be no different from that which would have occurred if the zero quantity had been completely removed, precisely equal to zero, or otherwise precisely zero.

[0160] For the purposes of this disclosure and the appended claims, any designation (e.g., first, second, third, etc., (a), (b), (c), etc., or (i), (ii), (iii), etc.) of elements, steps, limitations, or other parts of embodiments, examples, or claims is merely for clarity and should not be construed as implying any kind of order or priority of such designations. If any such order or priority is intentional, it will be expressly enumerated in the embodiments, examples, or claims, or in some instances, it will be implicit or inherent based on the specific content of the embodiments, examples, or claims. In the appended claims, if the provisions of 35 USC § 112(f) are to be invoked in an apparatus claim, the word “apparatus” will appear in that apparatus claim. If those provisions are to be invoked in a method claim, the word “for the step of…” will appear in that method claim. Conversely, if the words “apparatus” or “for the step of…” do not appear in the claim, then the provisions of 35 USC § 112(f) are not intended to be invoked in that claim.

[0161] If any one or more disclosures are incorporated herein by reference and such incorporated disclosures conflict in whole or in part with this disclosure, or differ in scope from this disclosure, then this disclosure shall prevail as to the extent of the conflict, the broader disclosure, or the broader definitions of terms. If any of such incorporated disclosures conflict in whole or in part with each other, then the later-date disclosure shall prevail as to the extent of the conflict.

[0162] Abstracts are provided as needed to assist those searching for specific topics within the patent literature. However, these abstracts are not intended to imply that any particular claim necessarily covers any element, feature, or limitation listed therein. The scope of the subject matter covered by each claim should be determined solely by the enumeration of that claim.

Claims

1. A light-emitting device, comprising: An array comprising multiple microLEDs and non-emitting regions separating adjacent microLEDs; as well as A solid-state wavelength conversion layer disposed on the array and comprising: Multiple first regions aligned with the multiple microLEDs and comprising phosphor particles of a first characteristic size dispersed in a first transparent adhesive material, and The second region, aligned with the non-luminescent region, includes phosphor particles of a second characteristic size dispersed in a second transparent adhesive material, and the second region exhibits greater optical scattering than the first region.

2. The light-emitting device according to claim 1, wherein the first feature dimension is different from the second feature dimension.

3. The light-emitting device according to claim 1, wherein the second feature size is less than 50% of the first feature size.

4. The light-emitting device according to claim 1, wherein the first feature size is less than 10 μm, or the second feature size is less than 5 μm.

5. The light-emitting device according to claim 1, wherein the spacing between the microLEDs in the array is less than 0.10 mm, or the width of the non-light-emitting region separating adjacent microLEDs in the array is less than 0.010 mm.

6. The light-emitting device according to claim 1, (i) the first region includes phosphor particles of a first characteristic size embedded in a transparent first solid medium, and (ii) the second region includes phosphor particles of a second characteristic size embedded in a transparent second solid medium.

7. The light-emitting device according to claim 6, wherein the first region differs from the second region in characterizing the different components or refractive indices of the first solid medium and the second solid medium.

8. The light-emitting device according to claim 6, further comprising scattering particles embedded in the second solid medium.

9. The light-emitting device according to claim 6, wherein the first solid medium comprises one or more polymers, or the second solid medium comprises one or more polymers.

10. The light-emitting device according to claim 6, wherein the first solid medium comprises one or more silicone resins, and the second solid medium comprises one or more silicone resins.

11. The light-emitting device according to claim 6, wherein the first solid medium and the second solid medium have the same material composition.

12. The light-emitting device according to claim 1, (i) the first region includes phosphor particles of a first characteristic size and a transparent first coating on the phosphor particles of the first region to bond the phosphor particles of the first region together, and (ii) the second region includes phosphor particles of a second characteristic size and a transparent second coating on the phosphor particles of the second region to bond the phosphor particles of the second region together.

13. The light-emitting device of claim 12, wherein the first region differs from the second region in characterizing the different sizes, number densities, or volume fractions of the gaps between phosphor particles in the first region and the gaps between phosphor particles in the second region.

14. The light-emitting device of claim 12, wherein the first region differs from the second region in characterizing the different thicknesses, compositions or refractive indices of the first coating and the second coating.

15. The light-emitting device according to claim 12, wherein the first coating has a thickness greater than 0.20 μm, or the second coating has a non-zero thickness of less than 0.10 μm.

16. The light-emitting device according to claim 12, wherein the first coating comprises one or more metal or semiconductor oxides, and the second coating comprises one or more metal or semiconductor oxides.

17. The light-emitting device according to claim 12, wherein the first coating and the second coating have the same material composition.

18. The light-emitting device of claim 12, wherein the first coating or the second coating comprises one or more materials compatible with formation using an atomic layer deposition (ALD) process or a conformal chemical vapor deposition (CVD) process.

19. The light-emitting device according to claim 12, (i) the characteristic thickness of the second coating is less than 50% of the characteristic thickness of the first coating, or (ii) the number density or volume fraction of the voids between the phosphor particles in the first region is less than 50% of the number density or volume fraction of the voids between the phosphor particles in the second region.

20. The light-emitting device of claim 1, wherein the first region exhibits a contrast ratio greater than 5:1 for downconverted light exiting the wavelength conversion layer from an adjacent first region of the wavelength conversion layer, the downconverted light being generated by the absorption of light emitted by the microLED and subsequent emission of downconverted light at a wavelength longer than that of the light emitted by the microLED.

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