Pixel isolation structure and manufacturing method thereof

Abstract

The described processing method includes forming a group of LED structures on a substrate layer to form a patterned LED substrate. The method also includes depositing a light absorbing material on the patterned LED substrate, wherein the light absorbing material includes at least one photocurable compound and at least one ultraviolet light absorbing material. The method further includes exposing a portion of a light absorbing material to patterned light, wherein the patterned light cures the exposed portion of the light absorbing material into a pixel isolation structure. The method additionally includes depositing isotropic layers on top and side portions of the pixel isolation structure, wherein the LED structure is substantially free of isotropic light reflecting layers in a deposited state.

Description

Technical Field

[0001] This application claims the benefit of and priority to U.S. Patent Application No. 63 / 406,929, filed on September 15, 2022, entitled “PIXEL ISOLATION STRUCTURES AND METHODS OF MAKING THEM,” the entire contents of which are hereby incorporated by reference.

[0002] The present technology relates to displays having pixels including pixel isolation structures to prevent crosstalk between adjacent pixels. Background Art

[0003] High-resolution light-emitting diode (LED) displays may include millions of micron-sized pixels arranged to form a viewing screen. Conventional LED displays produce color images by filtering white light from an LED light source into red, green, and blue pixels that are emitted at different intensities across the viewing screen. Other LED displays excite organic or inorganic compounds so that they emit light of a specific color, such as red, green, or blue, depending on the pixel. The LED displays typically require fewer filters to block light of undesirable colors and can produce a more accurate color gamut. However, they emit and scatter light in all directions, which can cause photoluminescent crosstalk between adjacent pixels, which can distort the color of the displayed image.

[0004] Therefore, display devices containing stimulable light-emitting materials need pixel designs that produce images with less photoluminescent crosstalk. The present technology addresses these and other needs. Summary of the invention

[0005] Embodiments of the present technology include a processing method, the processing method including forming a group of LED structures on a substrate layer to form a patterned LED substrate. The method also includes depositing a light absorbing material on the patterned LED substrate, wherein the light absorbing material includes at least one light curable compound and at least one ultraviolet light absorbing material. The method further includes exposing a portion of the light absorbing material to patterned light, wherein the patterned light cures the exposed portion of the light absorbing material into a pixel isolation structure. The method additionally includes depositing an isotropic layer on a top portion and a side portion of the pixel isolation structure, wherein the LED structure is substantially free of an isotropic light reflecting layer in the deposited state.

[0006] In additional embodiments, depositing the light absorbing material onto the patterned LED substrate comprises spin coating the light absorbing material onto the patterned LED substrate. In further embodiments, at least one photocurable compound in the light absorbing material comprises an epoxy-based photocurable material. In further embodiments, at least one ultraviolet light absorbing compound in the light absorbing material comprises a benzotriazole derivative, a 2-[3-(2H-benzotriazole-2-yl)-4-hydroxyphenyl] derivative, and a triazine derivative. In further embodiments, the method further comprises rinsing the uncured light absorbing material from the patterned LED substrate after curing the exposed portion of the light absorbing material into the pixel isolation structure. In further embodiments, the deposition of the isotropic light reflecting layer comprises directional deposition of the isotropic light reflecting layer on the top portion and the side portion of the pixel isolation structure, and wherein the directional deposition does not deposit the isotropic light reflecting layer on the top surface of the LED structure. In further embodiments, the pixel isolation structure forms the sidewalls of the photoluminescent region on the LED structure of the patterned LED substrate. In yet further embodiments, the pixel isolation structure forms the sidewalls of the photoluminescent region on the LED structure of the patterned LED substrate.

[0007] Additional embodiments of the present technology include a processing method, the processing method including depositing a light absorbing material on a substrate, wherein the light absorbing material includes at least one photocurable compound and at least one ultraviolet light absorbing compound. The method also includes exposing a portion of the light absorbing material to patterned light, wherein the patterned light cures the exposed portion of the light absorbing material into a first portion of a pixel isolation structure, and wherein the first portion of the pixel isolation structure forms a sidewall of a photoluminescent region located on the substrate. The method further includes depositing an isotropic light reflecting layer on the sidewall of the first portion of the pixel isolation structure, wherein the substrate is substantially free of the as-deposited isotropic light reflecting layer.

[0008] In further embodiments, the method includes depositing a photoluminescent material in at least a portion of the photoluminescent region to form a photoluminescent component. In additional embodiments, the method further includes attaching the photoluminescent component to a patterned LED substrate, wherein the patterned LED substrate includes a second portion of a pixel isolation structure, the second portion being bonded to the first portion of the pixel isolation structure along the top side of the first portion and the second portion of the pixel isolation structure. In further embodiments, at least one photocurable compound in the light absorbing material includes an epoxy-based photocurable material. In further embodiments, at least one ultraviolet light absorbing compound in the light absorbing material includes a benzotriazole derivative, a 2-[3-(2H-benzotriazole-2-yl)-4-hydroxyphenyl] derivative, and a triazine derivative. In further embodiments, the deposition of the isotropic light reflecting layer includes directional deposition of the isotropic light reflecting layer on the sidewalls of the first portion of the pixel isolation structure, wherein the directional deposition does not deposit the isotropic light reflecting layer on the substrate.

[0009] Additional embodiments of the present technology include a display structure comprising a light emitting diode structure operable to generate ultraviolet light. The structure further comprises: a photoluminescent region containing a photoluminescent material; and a pixel isolation structure comprising at least one photocurable compound and at least one ultraviolet light absorbing compound, wherein at least one sidewall of the photoluminescent region comprises the pixel isolation structure. The structure also comprises a light reflecting layer located between the photoluminescent material in the photoluminescent region and the pixel isolation structure.

[0010] In further embodiments, the light emitting diode structure comprises a micro-light emitting diode operable to generate ultraviolet light characterized by a wavelength of less than or about 420 nm. In further embodiments, the photoluminescent material in the photoluminescent region comprises a quantum dot material operable to absorb ultraviolet light from the light emitting diode structure and emit visible light characterized by a wavelength greater than 420 nm. In further embodiments, at least one photocurable compound in the light absorbing material comprises an epoxy-based photocurable material. In further embodiments, at least one ultraviolet light absorbing compound in the light absorbing material comprises a benzotriazole derivative, a 2-[3-(2H-benzotriazole-2-yl)-4-hydroxyphenyl] derivative, and a triazine derivative. In further embodiments, the light reflecting layer comprises at least one metal compound selected from the group consisting of aluminum, copper, chromium, silver, gold, platinum, and molybdenum.

[0011] Compared with the conventional method of manufacturing a pixel structure including a light-emitting diode component and a photoluminescent region containing a photoluminescent material, the present technology provides many benefits. In the conventional manufacturing method, the patterned LED substrate is covered by a silicon-containing passivation film before undergoing a series of photolithographic patterning operations to form a support for anisotropically deposited reflective light reflecting layer. Both deposition and removal operations for the passivation film, the photoresist, and the portion of the light reflecting layer are required to form a pixel structure including both the light-emitting diode component and the photoluminescent region. All of the operations significantly reduce the manufacturing efficiency of the pixel structure. In contrast, the embodiments of the present technology deposit a light-absorbing material, which includes both a photocurable compound and an ultraviolet light-absorbing compound that can be cured into a pixel isolation structure. The embodiments of the present technology allow a single deposition and patterned curing of the light-absorbing material to form a pixel isolation structure, instead of depositing, patterning, and removing multiple operations of the light-curable material to form a pixel isolation structure. The initial light-absorbing material is wet and can be spin-coated on the structured LED substrate, and the uncured portion of the light-absorbing material after patterning can be washed away in a single operation. Embodiments of the present technology also include directional deposition of a reflective light reflecting layer that deposits the light reflecting layer on those portions of the pixel isolation structure, which increases the percentage of light directed into the displayed image while leaving other portions of the pixel structure uncoated, such as the top surface of the light emitting diode structure. This eliminates another removal operation in the traditional manufacturing process that opens the blanket deposited light reflecting layer at those LED surfaces to allow light generated by the LED to be transmitted into the photoluminescent region of the pixel structure. These and other embodiments and their many advantages and features are described in more detail in conjunction with the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A further understanding of the nature and advantages of the invention may be realized by reference to the remainder of the specification and to the drawings, wherein like reference components are used throughout the several drawings to represent like parts. In some cases, a sub-label is associated with a reference component and is followed by a hyphen to represent one component of a plurality of similar components. When a reference component is referenced without specifying an existing sub-label, the reference component is intended to represent all such plurality of similar components.

[0013] Figure 1 A flow diagram illustrating selected operations of an illustrative method of fabricating a pixel structure in accordance with embodiments of the present technology.

[0014] FIG. 2A to FIG. 2E Illustrated are simplified cross-sectional views of stages in the fabrication of an illustrative single pixel structure in accordance with embodiments of the present technology.

[0015] Figure 3Another flow chart illustrating selected operations of an illustrative method of fabricating a pixel structure in accordance with embodiments of the present technology.

[0016] FIG. 4A to FIG. 4D Additional simplified cross-sectional views of stages in the fabrication of an illustrative single pixel structure in accordance with embodiments of the present technology are illustrated. DETAILED DESCRIPTION

[0017] Technological advances in high-resolution displays include the development of microscopic light-emitting diodes (µLEDs) from inorganic semiconductor materials and the use of photoluminescent materials such as quantum dots in displays. µLEDs are made of layers of semiconductor materials, such as indium gallium nitride (InGaN), that can be arranged to emit light of a specific peak emission wavelength when excited by an applied electric field. Semiconductor manufacturing processes are used to make µLEDs that are less than or about 50 μm in their longest dimension and that are operable to emit red, green, or blue light. Quantum dots are nanometer-sized particles of inorganic material that can emit light of a specific color after being excited by more energetic light. The color of the light emitted can depend on one or more properties of the particles, including their size, shape, and composition, among other properties. For quantum dots made of inorganic semiconductor materials, the color of the light they emit depends on the energy gap between the conduction band and the valence band of the dot. When a quantum dot is excited, one or more electrons jump from the lower energy valence band to the higher energy conduction band. When the excited electrons fall back to the valence band, the color of the light they emit depends on the size of the energy gap between the valence band and the conduction band. The narrower the energy gap, the more the emitted light is shifted toward the red, while the wider the energy gap, the more the emitted light is shifted toward the blue. By adjusting one or more properties of the quantum dots that change the energy gap between the conduction band and the valence band, quantum dots can be made to emit light of almost any color in the visible spectrum.

[0018] An additional advancement is the combination of µLEDs and quantum dots in high-resolution displays. The µLEDs are independently turned on and off by electronic circuitry in the backplane control panel to create a light source that light-excites the quantum dots. A higher energy µLED light source, such as blue or ultraviolet light, excites the quantum dots and causes them to emit light of a specific lower energy color, such as blue, green, orange, or red. The excited quantum dots can emit light with improved emission characteristics, such as a narrower full-width half-maximum wavelength spectrum than the µLEDs. The ability of the quantum dots to emit light with sharper colors reduces the number of color filters and polarizers needed in the display to block light of undesirable colors from contaminating the displayed image.

[0019] Unfortunately, conventional manufacturing methods for manufacturing pixel structures including a µLED and a photoluminescent region including a photoluminescent material have multiple deposition, patterning, and removal operations to form a pixel isolation structure and a reflective light reflecting layer along with the stack of the µLED and the photoluminescent region. These conventional manufacturing methods may include covering the LED structure with a silicon-containing passivation film (such as silicon nitride) to protect the LED structure during the formation of the pixel isolation structure. Conventional manufacturing methods may also include a series of photolithographic patterning operations to form a support for the anisotropically deposited reflective light reflecting layer. Both deposition and removal operations for the passivation film, the photolithographic photoresist, and portions of the light reflecting layer are required to form a pixel structure including both a light emitting diode component and a photoluminescent region. All of these operations significantly reduce the manufacturing efficiency of the pixel structure.

[0020] The present technology solves these and other problems of manufacturing methods for manufacturing pixel structures by forming pixel isolation structures and reflective light reflecting layers with significantly fewer operations. In an embodiment, the manufacturing method of the present invention deposits a light absorbing material, the light absorbing material including a light curable compound and an ultraviolet light absorbing compound that can be cured into a pixel isolation structure. Embodiments of the present technology allow a single deposition and patterned curing of the light absorbing material to form the pixel isolation structure, instead of depositing, patterning, and removing multiple operations of the light curable material to form the pixel isolation structure. In an additional embodiment, the initial light absorbing material is wet and can be spin-coated on the structured LED substrate, and the uncured portion of the light absorbing material after patterning can be washed away in a single operation. In another embodiment, a directional deposition of a reflective light reflecting layer can be performed, the directional deposition depositing the light reflecting layer on those portions of the pixel isolation structure, which increases the percentage of light directed into the displayed image, while leaving other portions of the pixel structure uncoated, such as the top surface of the light emitting diode structure. This eliminates another removal operation in the traditional manufacturing process, the other removal operation opens the blanket deposited light reflecting layer at those LED surfaces to allow the light generated by the LED to be transmitted into the photoluminescent region of the pixel structure.

[0021] Figure 1 A flow chart of selected operations in a method 100 for manufacturing a pixel structure 200 according to an embodiment of the present technology is illustrated. The method 100 may or may not include one or more operations before the method begins, including front-end processing, deposition, etching, polishing, cleaning, or any other operations that may be performed before the operations. The method may include optional operations that may or may not be particularly associated with some embodiments of the method according to the present technology. The method 100 describes operations for forming an embodiment of a pixel structure, one of which is illustrated in simplified schematic form as Figure 2E The pixel structure 200 in FIG. 1 and another operation in the operation is shown as follows: Figure 4D Pixel structure 400 in. Figure 2E and Figure 4D The cross-sectional views of the pixel structures 200 and 400 in FIG. 1 are cut-away cross-sectional views illustrating a pixel structure that is cut between a first pair of sub-pixels and a second pair of sub-pixels and is cut to reveal a cross-sectional linear arrangement of red pixels, green pixels, blue pixels, and blank pixels. Figure 2E and Figure 4D Only partial schematics with limited detail are shown. In additional embodiments not shown, the exemplary pixel structure may contain additional layers, regions, and materials with aspects as shown, as well as alternative structural and material aspects that may still benefit from any of the aspects of the present technology.

[0022] The method 100 includes forming a patterned LED structure 210a to 210d on a substrate 202 at operation 105, such as Figure 2A . In embodiments, the LED structures 210a to 210d may be µLED structures operable to emit blue light or ultraviolet light. In some embodiments, the substrate 202 may be removed to expose the surface on which the photoluminescent region is formed and the LED structures 210a to 210d. In other embodiments, the substrate 202 may form a backplane in electronic communication with the LED structures 210a to 210d. In other embodiments, the LED structures 210a to 210d may be operable to emit ultraviolet light or blue light. In yet another embodiment, the LED structures 210a to 210d may be operable to emit light characterized by a peak emission wavelength of less than or about 400 nm, less than or about 390 nm, less than or about 380 nm, less than or about 370 nm, less than or about 360 nm, less than or about 350 nm, less than or about 340 nm, less than or about 330 nm, or less. In additional embodiments, the LED structures 210a to 210d are characterized by a width of less than or about 10 μm, less than or about 5 μm, less than or about 4 μm, less than or about 3.5 μm, less than or about 3 μm, less than or about 2.5 μm, less than or about 2 μm, less than or about 1.5 μm, less than or about 1 μm, or less.

[0023] In an embodiment, the LED structures 210a to 210d may be LED structures containing gallium and nitrogen. In another embodiment, the LED structures 210a to 210d may be gallium nitride LED structures epitaxially formed on a substrate or a previously formed LED structure. In an additional embodiment, the substrate 202 may be a silicon substrate or a sapphire substrate as well as other types of substrates. In still additional embodiments, the LED structures 210a to 210d may further include an n-doped GaN layer and a p-doped GaN layer. A multi-quantum well (MQW) region is formed between the n-doped and p-doped GaN layers, in which light emitted by the LED structures 210a to 210d is generated. The LED structures 210a to 210d may further include a conductive N pad contact, which forms a path for current to pass through the n-doped GaN layer. The LED structures 210a to 210d may also include a conductive P pad contact, which forms a path for current to pass through the p-doped GaN layer. The N-pad and P-pad contacts can be connected to conductive layers in the LED subpixels, or directly to contacts in the control circuitry of the backplane. In an embodiment, an electrical signal from the control circuitry causes a flow of current through the LED structures 210a to 210d, which causes light to be emitted from the MQW region of the structure. In additional embodiments, the MQW region is formed to emit light characterized by a repeatable peak intensity wavelength and quantum efficiency of an applied electrical signal (e.g., current and / or voltage). In an embodiment, the peak intensity wavelength of light emitted from the MQW region can be an ultraviolet wavelength (e.g., a wavelength of light less than or about 400 nm).

[0024] The method 100 may further include depositing a light absorbing material 212 on the substrate 202 and the patterned LED structures 210a to 210d, as shown in FIG. 2B. In an embodiment, the light absorbing material 212 may be applied to the substrate 202 and the patterned LED structures 210a to 210d as a liquid or wet slurry. In other embodiments, the light absorbing material 212 may be applied using one or more deposition techniques, such as spin coating, dip coating, spray coating, doctor blade coating, and inkjet coating, among other deposition techniques.

[0025] In an embodiment, the light absorbing material 212 includes at least one photoresist compound and at least one ultraviolet light absorbing compound. In additional embodiments, the photoresist compound may include one or more compounds such as naphthoquinone diazide, bis diphenyl ketone type photoinitiators, crosslinkers based on bis (arylazides), phenolic resins, poly (methyl methacrylate), poly (methyl glutarimide) and different types of SU-8, acrylic monomer thiol-ene resins, polysiloxanes, polyvinyl cinnamate and other photoresist compounds.

[0026] In further embodiments, the ultraviolet light absorbing compound in the light absorbing material 212 may include one or more compounds, such as N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD); N,N'-bis(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB); N,N'-bis(phenanthrene-9-yl)-N,N'-bis(phenyl)-benzidine (PAPB or PPD); 4,7-diphenyl-1,10-phenanthroline (BPhen); bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum (BAlq); tris-(8-hydroxyquinoline)aluminum (Alq); fused tetraphenyl (C8H 12 ); 4-phenyl (4P); and 6-phenyl (6P); Tinuvin CarboPreotect available from BASF, the Riasorb line of UV absorbers from Rianlon; titanium oxide; zinc oxide; and carbon black; as well as other ultraviolet light absorbing compounds.

[0027] In further embodiments, the light absorbing material 212 may include a solvent for a photoresist compound and / or a UV light absorbing compound. In further embodiments, the solvent may include gamma-butyrolactone (GBL) and / or cyclopentanone, cyclohexanone, propyl methyl ether acetate, methoxypropyl ether acetate, anisole, toluene, xylene, dimethylformamide, acetone, acetylacetone, methyl ethyl ketone, methyl isobutyl ketone, and other solvents.

[0028] The method 100 may also include patterning the light absorbing material 212 deposited on the substrate 202 and the patterned LED structures 210a to 210d by exposing the material to patterned light at operation 115. In an embodiment, the light may be passed through a photolithographic mask to form a pattern of light projected onto the light absorbing material 212. In additional embodiments, the patterned light cures the light absorbing material 212 exposed to the light while leaving the material not exposed to the light in an uncured state. In further embodiments, the patterned light may include ultraviolet light having sufficient energy to cure the photocurable compound in the light absorbing material 212 by, for example, photochemical crosslinking of the photocurable compound.

[0029] In additional embodiments, the cured portion of the light absorbing material 212 may form pixel isolation structures 214a to 214e made of at least one cured light-curable compound and at least one ultraviolet light absorbing compound in the light absorbing material. As shown in FIG. 2C , the pixel isolation structures 214a to 214e may be formed between adjacent patterned LED structures 210a to 210d. In additional embodiments, the pixel isolation structures 214a to 214e may also be formed in the gap space between the patterned LED structures 210a to 210d and the substrate 202. In further embodiments, the pixel isolation structures 214a-214e can be characterized as a light absorbing barrier layer operable to absorb high energy ultraviolet light and wavelengths less than or about 350 nm, less than or about 340 nm, less than or about 330 nm, less than or about 320 nm, less than or about 310 nm, less than or about 300 nm, less than or about 290 nm, less than or about 280 nm, less than or about 270 nm, less than or about 260 nm, less than or about 250 nm, or less. In further embodiments, the pixel isolation structures 214a-214e can absorb greater than or about 50%, greater than or about 60%, greater than or about 70%, greater than or about 80%, greater than or about 90%, greater than or about 92.5%, greater than or about 95%, greater than or about 99%, or more of the high energy ultraviolet light reaching the barrier layer.

[0030] The method 100 may also include removing the uncured light absorbing material 212 at operation 120. In an embodiment, the uncured light absorbing material 212 may be removed by a wet rinsing operation that washes the uncured material off the substrate 202 and the patterned LED structures 210a to 210d. In additional embodiments, the removal of the uncured light absorbing material 212 leaves the top surfaces of the LED structures 210a to 210d free of light absorbing material. This allows the LED structures 210a to 210d to emit light into the photoluminescent regions 218a to 218d without attenuation from the light absorbing material 212, without requiring an additional removal operation.

[0031] As shown in FIG. 2C , the removal of the uncured light absorbing material 212 leaves pixel isolation structures 214 a to 214 e located between adjacent LED structures 210 a to 210 d. In further embodiments, the pixel isolation structures extend above the height of the LED structures 210 a to 210 d to form a portion of the sidewall portions of the photoluminescent regions 218 a to 218 d. In further embodiments, the pixel isolation structures 214 a to 214 e may be characterized by a height of greater than or about 2.5 μm, greater than or about 5 μm, greater than or about 7.5 μm, greater than or about 10 μm, greater than or about 12.5 μm, greater than or about 15 μm, greater than or about 17.5 μm, greater than or about 20 μm, or greater. In still additional embodiments, the pixel isolation structures 214a-214e may be characterized by a width of less than or about 5 μm, less than or about 4.5 μm, less than or about 4 μm, less than or about 3.5 μm, less than or about 3 μm, less than or about 2.5 μm, less than or about 2 μm, or less. In further embodiments, the pixel isolation structures 214a-214e may be characterized by an aspect ratio of height to width of greater than or about 1.5:1, greater than or about 2:1, greater than or about 2.5:1, greater than or about 3:1, greater than or about 3.5:1, greater than or about 4:1, greater than or about 4.5:1, greater than or about 5:1, or greater.

[0032] The method 100 still further includes depositing an isotropic light reflecting layer 220 on portions of the pixel isolation structures 214a to 214e at operation 125. In the embodiment shown in FIG. 2D , the isotropic light reflecting layer 220 is deposited on the top and side surfaces of the pixel isolation structures 214a to 214e, but not on the top surfaces of the LED structures 210a to 210d adjacent to the photoluminescent regions 218a to 218d. In an embodiment, the lack of a light reflecting layer on the top surfaces of the LED structures 210a to 210d eliminates a patterned etching operation to remove the light reflecting layer from the top surfaces, while retaining the light reflecting layer on the surfaces of the pixel isolation structures 214a to 214d.

[0033] In an embodiment, the deposition of the isotropic light reflecting layer 220 may include sputtering or otherwise directing metal onto the pixel isolation structures 214a to 214e at an angle other than 90° relative to the substrate 202. In further embodiments, the substrate 202 may be rotated during the deposition of the isotropic light reflecting layer 220 to cover a larger portion of the sidewalls of the pixel isolation structures 214a to 214e and to keep the light reflecting layer from having a non-uniform thickness in a non-orthogonal metal deposition direction. In further embodiments, the metal forming the light reflecting layer 220 may be selected from the group consisting of: aluminum, copper, chromium, silver, gold, platinum, and molybdenum. In further embodiments, the light reflecting layer 220 may be operable to directly or indirectly reflect light in a direction that increases the efficiency of the pixel structure in converting the generated light into a displayed image. In an embodiment, a portion of the light generated by the LED structures 210a to 210d that was initially directed away from the photoluminescent regions 218a to 218d may be redirected by the light reflecting layer 220 in the direction of those photoluminescent regions. In additional embodiments, a portion of the light generated by the photoluminescent material 222a - 222c in the photoluminescent regions 218a - 218c that was initially directed away from the displayed image may be redirected by the light reflective layer 220 in the direction of the displayed image.

[0034] In additional embodiments, the light reflective layer 220 can have a reflective efficiency of greater than or about 50%, greater than or about 60%, greater than or about 70%, greater than or about 80%, greater than or about 90%, greater than or about 95%, greater than or about 99%, or more for reflecting light in the ultraviolet and visible portions of the electromagnetic spectrum. In further embodiments, the light reflective layer 220 can be operable to direct a greater portion of light emitted by the LED structures 210a-210d and the photoluminescent materials 222a-222c in the photoluminescent regions 218a-218c into a direction that facilitates illuminating a device, such as a display or other illuminable device component. In further embodiments, the light reflective layer 220 increases the intensity of light from a pixel structure illuminating a device by greater than or about 5%, greater than or about 10%, greater than or about 15%, greater than or about 20%, greater than or about 25%, or more, as compared to the same pixel structure lacking the light reflective layer.

[0035] The method 100 also includes depositing photoluminescent materials 222a to 222c into the photoluminescent regions 218a to 218c at operation 130, such as Figure 2EAs shown. In an embodiment, the photoluminescent material 222a to 222c may include organic luminescent compounds and / or inorganic luminescent particles known as quantum dots (QDs) that are operable to absorb light emitted from the LED structures 210a to 210d and emit light having specific color characteristics. In further embodiments, a different photoluminescent material 222a to 222c may be deposited in each of the photoluminescent regions 218a to 218c. In further embodiments, the pixel structure includes a fourth photoluminescent region 218d in which no photoluminescent material is deposited unless one of the other photoluminescent regions 218a to 218c fails to produce light within the parameters of the expected brightness and color. In this case, the photoluminescent region 218d is filled with the same type of photoluminescent material as the failed photoluminescent region and is operable to serve as a replacement for the failed photoluminescent region.

[0036] In further embodiments, the photoluminescent material 222a to 222c is deposited into the photoluminescent regions 218a to 218c formed in part by the pixel isolation structures 214a to 214e coated with the light reflective layer 220. In further embodiments, the pixel isolation structures 214a to 214e extend over and around the LED structures 210a to 210d. In further embodiments, the sub-pixel isolation structures may extend adjacent to and below the contact areas of the LED structures 210a to 210d, and may further extend downward to the backplane of the pixel structures. In further embodiments, the pixel isolation structures 214a to 214e may have a height greater than or about 2.5 μm, greater than or about 5 μm, greater than or about 7.5 μm, greater than or about 10 μm, greater than or about 12.5 μm, greater than or about 15 μm, greater than or about 17.5 μm, greater than or about 20 μm, or greater. In still additional embodiments, the pixel isolation structures 214a-214e may have a width of less than or about 5 μm, less than or about 4.5 μm, less than or about 4 μm, less than or about 3.5 μm, less than or about 3 μm, less than or about 2.5 μm, less than or about 2 μm, or less. In further embodiments, the pixel isolation structures 214a-214e may have an aspect ratio of height to width of greater than or about 1.5:1, greater than or about 2:1, greater than or about 2.5:1, greater than or about 3:1, greater than or about 3.5:1, greater than or about 4:1, greater than or about 4.5:1, greater than or about 5:1, or greater. In further embodiments, the pixel isolation structures 214a-214e reduce crosstalk generated by light from adjacent and nearby pixel structures. In embodiments, the reduction in intensity of light from adjacent and nearby pixel structures may be greater than or about 50%, greater than or about 60%, greater than or about 70%, greater than or about 80%, greater than or about 90%, greater than or about 95%, greater than or about 99%, or more.

[0037] In an embodiment, the pixel isolation structures 214a to 214e form sidewalls of the photoluminescent regions 218a to 218d, which also include a bottom side adjacent to the top surface of the LED structures 210a to 210d. In further embodiments, the bottom side of the photoluminescent regions 218a to 218d has a width of less than or about 10 μm, less than or about 5 μm, less than or about 4 μm, less than or about 3.5 μm, less than or about 3 μm, less than or about 2.5 μm, less than or about 2 μm, less than or about 1.5 μm, less than or about 1 μm, or less.

[0038] In further embodiments, the deposited photoluminescent material may include one or more photoluminescent precursors in a mixture or slurry, the mixture or slurry including a photocurable fluid and one or more photoluminescent particles or compounds. In further embodiments, the one or more photoluminescent compounds may include quantum dot materials that are operable to emit light having specific color characteristics when excited by a light source. In additional embodiments, these quantum dot materials may include nanoparticles made of one or more inorganic semiconductor materials such as indium phosphide, zinc selenide, zinc sulfide, silicon, silicates, and graphene, as well as doped inorganic oxides and other semiconductor materials. In further embodiments, the photocurable fluid may include one or more crosslinkable compounds, photoinitiators, and color converters. In further embodiments, the crosslinkable compound may include monomers that form polymers when cured. In further embodiments, the monomers may include acrylate monomers, methacrylate monomers, and acrylamide monomers. In further embodiments, the crosslinkable compound may include a negative photocurable material such as SU-8 photocurable material. In other embodiments, the photoinitiator may include phosphine oxide compounds and ketone compounds, as well as other types of photoinitiator compounds, which, when excited by ultraviolet light, generate free radicals that initiate the curing of unsaturated compounds. Commercially available photoinitiator compounds include Irgacure 184, Irgacure 819, Darocur 1173, Darocur 4265, Darocur TPO, Omnicat 250, and Omnicat 550, as well as other photoinitiators.

[0039] When the deposited photoluminescent material includes one or more photoluminescent precursors, the precursors may be cured to form the photoluminescent materials 220a to 220c. In an embodiment, the curing operation may include exposing the photoluminescent precursors in the photoluminescent regions 218a to 218c to a curing light that converts the photoluminescent precursors into the photoluminescent materials 220a to 220c. In other embodiments, the curing light may be characterized by a peak emission wavelength that is short enough to activate one or more of the photocurable compounds in the photocurable fluid of the photoluminescent precursor. In further embodiments, the curing light is characterized by a peak emission wavelength of less than or about 405 nm, less than or about 400 nm, less than or about 395 nm, less than or about 390 nm, less than or about 385 nm, less than or about 380 nm, less than or about 375 nm, less than or about 370 nm, less than or about 365 nm, less than or about 360 nm, less than or about 355 nm, less than or about 350 nm, less than or about 340 nm, less than or about 330 nm, less than or about 320 nm, less than or about 310 nm, less than or about 300 nm, or less. In further embodiments, the curing light can be supplied by the LED structure 210. In these embodiments, supplying the curing light from the LED structure 210 can allow the photoluminescent material 218 in the photoluminescent regions 214a to 214e to self-align with the LED structures 210a to 210d. As the sub-pixel size decreases and the pixel density increases, the self-alignment of the photoluminescent material with the LED structure becomes increasingly beneficial.

[0040] refer to Figure 3 and FIG. 4A to FIG. 4D , illustrates another embodiment of a method 300 for manufacturing a pixel structure 400 according to an embodiment of the present technology. In an embodiment, the method 300 includes depositing a light absorbing material on a substrate 402 at operation 310. In further embodiments, the substrate 402 may not include a patterned LED structure, which will be supplied in a separate component attached to a component including the substrate 302. In additional embodiments, the substrate 402 may be a transparent substrate capable of transmitting light generated in the photoluminescent regions 418a to 418d to display an image. In additional embodiments, the substrate 402 may be operable to be removed from the photoluminescent regions 418a to 418d.

[0041] In further embodiments, the light absorbing material includes at least one photocurable compound and at least one ultraviolet light absorbing material. In additional embodiments, substrate 402 may include a planar region on which the light absorbing material may be deposited as a blanket layer. In additional embodiments, the light absorbing material may be a liquid or slurry, and the light absorbing material 212 may be applied using one or more deposition techniques, such as spin coating, dip coating, spray coating, doctor blade coating, and inkjet coating, among other deposition techniques.

[0042] The method 300 also includes patterning the deposited light absorbing material at operation 315. In an embodiment, the patterning operation may include light passing through a photolithographic mask to form a pattern of light projected onto the light absorbing material. In additional embodiments, the patterned light cures the light absorbing material exposed to the light while leaving the material not exposed to the light in an uncured state. In other embodiments, the patterned light may include ultraviolet light having an energy sufficient to cure the light-curable compound in the light absorbing material by, for example, photochemical cross-linking of the light-curable compound.

[0043] The method 300 further includes removing the uncured light absorbing material at operation 320. In an embodiment, the removal of the uncured light absorbing material forms spaces for the photoluminescent regions 418a to 418d, such as Figure 4A As shown. In further embodiments, the photoluminescent regions 418a to 418d may include sidewall regions that are formed in part by the pixel isolation structures 414a to 414e made during patterning of the light absorbing material deposited on the substrate 402. In further embodiments, the photoluminescent regions 418a to 418d include a top surface formed by the surface of the substrate 402 on which the light absorbing material is deposited. In embodiments, the substrate 402 may be incorporated into the final pixel structure 400, or may be removed and replaced with a different component of the pixel structure.

[0044] The method 300 also includes depositing an isotropic light reflecting layer 420 on the pixel isolation structures 414a to 414e at operation 325, as shown in FIG. 4B. In an embodiment, the isotropic light reflecting layer 320 is deposited on the top and side surfaces of the pixel isolation structures 414a to 414e, but not on the surface of the substrate 302 forming the top surface of the photoluminescent regions 418a to 418d. In an embodiment, the lack of a light reflecting layer on the surface of the substrate 402 eliminates a patterned etching operation to remove the light reflecting layer from the surface while retaining the light reflecting layer on the surface of the pixel isolation structures 414a to 414e. In further embodiments, the metal forming the light reflecting layer 420 may be selected from the group consisting of aluminum, copper, chromium, silver, gold, platinum, and molybdenum. In further embodiments, the light reflecting layer 320 is operable to directly or indirectly reflect light in a direction that increases the efficiency of the pixel structure in converting the generated light into a displayed image.

[0045] The method 300 still also includes depositing photoluminescent materials 322a-322c into the photoluminescent regions 418a-418c at operation 330, as shown in FIG. 4C. In embodiments, the photoluminescent materials 422a-422c may include organic luminescent compounds and / or inorganic luminescent particles known as quantum dots (QDs) operable to absorb light emitted from the LED structures 410a-410d and emit light having specific color characteristics. In further embodiments, a different photoluminescent material 422a-422c may be deposited in each of the photoluminescent regions 418a-418c. In further embodiments, the pixel structure includes a fourth photoluminescent region 418d in which no photoluminescent material is deposited unless one of the other photoluminescent regions 418a-418c fails to produce light within the parameters of the desired brightness and color. In this case, the photoluminescent region 418d is filled with the same type of photoluminescent material as the failed photoluminescent region and is operable to serve as a replacement for the failed photoluminescent region.

[0046] The method 300 may further include bonding the substrate 402 having the photoluminescent regions 418a to 418d to the patterned LED substrate 450 at operation 335, such as Figure 4D In an embodiment, substrate 402 may be bonded to patterned LED substrate 450 with bonding layer 425 that holds the substrate bonded in the final pixel structure 400. In an embodiment, separate fabrication of photoluminescent regions 418a to 418d and patterned LED substrate 450 may accommodate different processing tolerances of different substrates, such as different thermal budgets and chemical exposures.

[0047] In embodiments of the present technology, pixel structures 200 and 400 can be combined with additional pixel structures to form a display component. In other embodiments, the display component can be incorporated into a display device, such as a headset, glasses, a screen or monitor, and other display devices. In other embodiments, a display component including the pixel structure of the present invention can be incorporated into a display device for virtual reality and / or augmented reality services.

[0048] In further embodiments, a display component incorporating the pixel structure of the present invention is characterized by a pixel density of greater than or about 500 pixels per inch (ppi), greater than or about 1000 ppi, greater than or about 1500 ppi, greater than or about 2000 ppi, greater than or about 2500 ppi, greater than or about 3000 ppi, greater than or about 3500 ppi, greater than or about 4000 ppi, greater than or about 4500 ppi, greater than or about 5000 ppi, or more. In further embodiments, the increased pixel density of the display component does not result in a decrease in the brightness of a displayed image produced by the display component. In embodiments, the image brightness may be characterized as greater than or about 100 nits, greater than or about 250 nits, greater than or about 500 nits, greater than or about 750 nits, greater than or about 1000 nits, greater than or about 2500 nits, or greater. In further embodiments, pixel structures of the present technology are characterized by an optical density greater than or about 0.5, greater than or about 0.75, greater than or about 0.8, greater than or about 0.9, greater than or about 0.95, greater than or about 0.99, or greater.

[0049] Several embodiments have been described, and those skilled in the art will recognize that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the present invention. In addition, in order to avoid unnecessarily obscuring the present invention, many well-known processes and components are not described. Therefore, the above description should not be construed as limiting the scope of the present invention.

[0050] Where a range of values ​​is provided, it is to be understood that, unless the context clearly indicates otherwise, each intervening value between the upper and lower limits of the range to one tenth of the unit of the lower limit is also specifically disclosed. Each smaller range between any specified value or intervening value in a specified range and any other specified value or intervening value in the specified range is contemplated. The upper and lower limits of the smaller range may be independently included in the range or excluded from the range, and the invention also contemplates each range in which either limit is included in the smaller range, none of the limits is included in the smaller range, or both limits are included in the smaller range, subject to any specifically excluded limits in the specified range. When a specified range includes one or both of the limits, a range excluding one or both of those included limits is also contemplated.

[0051] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a process" includes a plurality of such processes, and reference to "the pixel structure" includes reference to one or more pixel structures and equivalents thereof known to those skilled in the art, and so forth.

[0052] Furthermore, when used in this specification and the appended claims, the words “comprise,” “comprising,” “include,” and “including” are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, actions, or groups.

Claims

1. A processing method comprising the following steps: forming an LED structure group on the substrate layer to form a patterned LED substrate; A light absorbing material is deposited on the patterned LED substrate, wherein the light absorbing material comprises at least one photocurable compound and at least one ultraviolet light absorbing compound. exposing a portion of the light absorbing material to patterned light, wherein the patterned light cures the exposed portion of the light absorbing material into a pixel isolation structure; as well as An isotropic light reflecting layer is deposited on a top portion and a side portion of the pixel isolation structure, wherein the LED structure is substantially free of the deposited isotropic light reflecting layer.

2. The processing method of claim 1, wherein depositing the light absorbing material on the patterned LED substrate comprises: The light absorbing material is spin coated on the patterned LED substrate.

3. The processing method of claim 1, wherein the at least one photocurable compound in the light absorbing material comprises an epoxy-based photocurable material.

4. The processing method of claim 1, wherein the at least one ultraviolet light absorbing compound in the light absorbing material comprises a benzotriazole derivative, a 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl] derivative, or a triazine derivative.

5. The processing method according to claim 1, wherein the method further comprises: After curing the exposed portions of the light absorbing material into the pixel isolation structures, the uncured light absorbing material is rinsed away from the patterned LED substrate.

6. The processing method of claim 1, wherein the depositing of the isotropic light reflecting layer comprises: Directional deposition of the isotropic light reflecting layer on the top portion and side portions of the pixel isolation structure, and wherein the directional deposition does not deposit the isotropic light reflecting layer on the top surface of the LED structure.

7. The processing method of claim 1, wherein the pixel isolation structure forms a sidewall of a photoluminescent region on the LED structure of the patterned LED substrate.

8. The processing method according to claim 7, wherein the method further comprises: A photoluminescent material is deposited in the photoluminescent region.

9. A processing method comprising the following steps: depositing a light absorbing material on a substrate, wherein the light absorbing material comprises at least one photocurable compound and at least one ultraviolet light absorbing compound; exposing a portion of the light absorbing material to patterned light, wherein the patterned light cures the exposed portion of the light absorbing material into a first portion of a pixel isolation structure, and wherein the first portion of the pixel isolation structure forms a sidewall of a photoluminescent region located on the substrate; as well as An isotropic light reflecting layer is deposited on the sidewall of the first portion of the pixel isolation structure, wherein the substrate is substantially free of the deposited isotropic light reflecting layer.

10. The processing method according to claim 9, wherein the method further comprises: A photoluminescent material is deposited in at least a portion of the photoluminescent region to form a photoluminescent feature.

11. The processing method according to claim 9, wherein the method further comprises: The photoluminescent component is attached to a patterned LED substrate, wherein the patterned LED substrate includes a second portion of the pixel isolation structure joined to the first portion of the pixel isolation structure along a top portion of the first and second portions of the pixel isolation structure.

12. The process of claim 9, wherein the at least one photocurable compound in the light absorbing material comprises an epoxy-based photocurable material.

13. The processing method of claim 9, wherein the at least one ultraviolet light absorbing compound in the light absorbing material comprises a benzotriazole derivative, a 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl] derivative, or a triazine derivative.

14. The processing method of claim 9, wherein said depositing of said isotropic light reflecting layer comprises: Directional deposition of the isotropic light reflecting layer on the sidewalls of the first portion of the pixel isolation structure, and wherein the directional deposition does not deposit the isotropic light reflecting layer on the substrate.

15. A display structure comprising: a light emitting diode structure operable to generate ultraviolet light; a photoluminescent region, wherein the photoluminescent region contains a photoluminescent material; a pixel isolation structure comprising at least one photocurable compound and at least one ultraviolet light absorbing compound, wherein at least one sidewall of the photoluminescent region includes the pixel isolation structure; as well as A light reflecting layer is located between the photoluminescent material in the photoluminescent area and the pixel isolation structure.

16. The display structure of claim 15, wherein the light emitting diode structure comprises micro-light emitting diodes operable to generate ultraviolet light characterized by a wavelength of less than or about 420 nm.

17. The display structure of claim 15, wherein the photoluminescent material in the photoluminescent region comprises a quantum dot material operable to absorb the ultraviolet light from the light emitting diode structure and emit visible light characterized by a wavelength greater than 420 nm.

18. The display structure of claim 15, wherein the at least one photocurable compound in the light absorbing material comprises an epoxy-based photocurable material.

19. The display structure of claim 15, wherein the at least one ultraviolet light absorbing compound in the light absorbing material comprises a benzotriazole derivative, a 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl] derivative, or a triazine derivative.

20. The display structure of claim 15, wherein the light reflective layer comprises at least one metal selected from the group consisting of aluminum, copper, chromium, silver, gold, platinum, and molybdenum.

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