Transparent optical structure, micro light emitting structure and method of manufacture

Abstract

The application provides a transparent optical structure, a micro light emitting structure and a preparation method, and belongs to the technical field of light emitting. The preparation method of the optical structure comprises the following steps: obtaining an optical carrier, coating photoresist on the surface of the optical carrier; performing exposure and development on the optical carrier coated with the photoresist, so as to obtain photoresist of a plurality of microlens front structures; and etching the optical carrier after development, so as to set a microlens part on the surface of the optical carrier, thereby obtaining the optical structure.

Description

Technical Field

[0001] This invention relates to the field of light-emitting technology, and in particular to a transparent optical structure, a micro-light-emitting structure, and a method for its fabrication. Background Technology

[0002] Micro-LED technology boasts advantages in brightness, luminous efficacy, reliability, response time, and color saturation, thus its applications cover AR (Augmented Reality), HUD (head-up display), transparent displays, flexible displays, wearable devices, high-end displays, and more. Currently, sapphire wafers such as PSS (Phase Shifting Surface) are difficult to apply to the various specifications and sizes of micro-LEDs used in actual production. Summary of the Invention

[0003] In view of this, the present invention provides a transparent optical structure, a micro-luminescent structure, and a method for its preparation.

[0004] This invention provides the following technical solution: a method for fabricating a transparent optical structure, the method comprising the following steps:

[0005] Obtain an optical substrate and coat its surface with photoresist;

[0006] The optical substrate coated with photoresist is exposed and developed to obtain photoresist for multiple microlens front structures.

[0007] After etching and development, an optical carrier is used to set microlens portions on the surface of the optical carrier to obtain an optical structure.

[0008] Further, the process of exposing and developing the photoresist-coated optical substrate to obtain photoresist with multiple microlens front structures; etching and developing the developed optical substrate to form microlens portions on the surface of the optical substrate to obtain an optical structure, includes: exposing and developing a first portion of the first photoresist coated on the optical substrate.

[0009] The optical substrate coated with the developed first photoresist is etched to transfer the first part of the exposed microlens front structure onto the optical substrate.

[0010] After cleaning away the first photoresist on the surface of the optical substrate, a second photoresist layer is coated on the etched surface of the optical substrate.

[0011] The second portion of the second photoresist coated on the optical carrier is exposed and developed.

[0012] The optical substrate coated with the developed second photoresist is etched to transfer the exposed second part of the microlens front structure onto the optical substrate.

[0013] The first and second parts are misaligned in their orthographic projections onto the plane of the optical slide.

[0014] Furthermore, the thickness of the first photoresist is equal to the thickness of the second photoresist.

[0015] Furthermore, the exposure method includes at least one of the following: exposing and developing the photoresist using an exposure machine and a grayscale exposure plate;

[0016] The photoresist is exposed and developed using an electron beam exposure machine.

[0017] Furthermore, the microlens front structure includes at least one of a hemisphere, a frustum, and a cone.

[0018] Some embodiments of the present invention provide a transparent optical structure, which is prepared using the method described above.

[0019] Furthermore, it includes a substrate and a plurality of microlens portions disposed on one side of the substrate in the thickness direction;

[0020] The microlens portion is a protrusion, and the shape of the microlens portion is any one or a combination of two or more of the following: hemispherical, conical, polygonal prism, and oblique prism.

[0021] Some embodiments of the present invention provide a micro-luminescent structure, including a transparent optical structure fabricated by the method for fabricating the transparent optical structure described above;

[0022] Or the aforementioned transparent optical structure;

[0023] The transparent optical structure has multiple micro-light-emitting chips on the side opposite to the microlens section.

[0024] In the thickness direction of the transparent optical structure, at least a portion of the micro-light-emitting chips corresponds one-to-one with the microlens portion.

[0025] Furthermore, the number of the micro-light-emitting chips corresponds to the number of the microlens portions, and each micro-light-emitting chip corresponds to one microlens portion.

[0026] Some embodiments of the present invention provide a method for fabricating a micro-luminescent structure, comprising the following steps:

[0027] Obtain an optical carrier containing multiple micro-light-emitting chips;

[0028] The side of the optical carrier facing away from the plurality of micro-light-emitting chips is processed using the transparent optical structure fabrication method described above to obtain a micro-light-emitting structure with a microlens portion corresponding to the micro-light-emitting chips.

[0029] Some embodiments of the present invention provide a method for fabricating a micro-luminescent structure, comprising the following steps:

[0030] Obtain transparent optical structures and micro-light-emitting chips;

[0031] The micro-light-emitting chip is disposed on the side of the transparent optical structure away from the microlens to obtain the micro-light-emitting structure.

[0032] The embodiments of the present invention have the following advantages: by processing the photoresist coated on the optical substrate into a microlens front structure, and using the photoresist of the microlens front structure to etch the optical substrate, the barrier of limiting the fabrication of light-emitting structures to 2D structure etching can be broken, and a 3D structure pattern can be obtained. The 3D structure etched Micro Lens can be better compatible with various types, specifications and arrangements of micro LED structures, thereby effectively improving the performance of micro LED structures.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A flowchart of a first embodiment of a method for fabricating a transparent optical structure according to some embodiments of the present invention is shown;

[0036] Figure 2 A flowchart illustrating a second embodiment of a method for fabricating a transparent optical structure according to some embodiments of the present invention is shown;

[0037] Figure 3 This diagram illustrates a structural schematic of an optical carrier from one perspective in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0038] Figure 4 This diagram illustrates a method for fabricating a transparent optical structure according to some embodiments of the present invention, showing a schematic diagram of the optical carrier and the first photoresist.

[0039] Figure 5This diagram illustrates a first embodiment of the exposure and development of a first photoresist in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0040] Figure 6 This diagram illustrates a first embodiment of the exposure and development of a second photoresist in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0041] Figure 7 A first structural schematic diagram of a transparent optical structure provided by some embodiments of the present invention is shown;

[0042] Figure 8 This diagram illustrates a second embodiment of the exposure and development of a first photoresist in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0043] Figure 9 This diagram illustrates a structural schematic of the first etching method of an optical carrier in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0044] Figure 10 This diagram illustrates the structure of the optical carrier and the second photoresist in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0045] Figure 11 This diagram illustrates a second embodiment of the exposure and development of a second photoresist in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0046] Figure 12 A second structural schematic diagram of a transparent optical structure provided by some embodiments of the present invention is shown;

[0047] Figure 13 The diagram illustrates a third embodiment of the exposure and development of a first photoresist in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0048] Figure 14 This diagram illustrates a second etching method for an optical carrier in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0049] Figure 15 The diagram illustrates a third embodiment of the exposure and development of a second photoresist in a method for fabricating a transparent optical structure according to some embodiments of the present invention.

[0050] Figure 16 A third structural schematic diagram of a transparent optical structure provided by some embodiments of the present invention is shown;

[0051] Figure 17 A flowchart of a third embodiment of a method for fabricating a transparent optical structure provided by some embodiments of the present invention is shown;

[0052] Figure 18 A flowchart of a fourth embodiment of a method for fabricating a transparent optical structure provided by some embodiments of the present invention is shown;

[0053] Figure 19 A flowchart of a fifth embodiment of a method for fabricating a transparent optical structure provided by some embodiments of the present invention is shown;

[0054] Figure 20 This diagram illustrates a schematic view of a transparent light-emitting structure provided by some embodiments of the present invention.

[0055] Figure 21 A flowchart of a sixth embodiment of a method for fabricating a transparent optical structure provided by some embodiments of the present invention is shown;

[0056] Figure 22 A flowchart of a first embodiment of a method for fabricating a micro-luminescent structure provided by some embodiments of the present invention is shown;

[0057] Figure 23 A flowchart of a second embodiment of a method for fabricating a microluminescent structure provided by some embodiments of the present invention is shown.

[0058] Explanation of key component symbols:

[0059] 100 - Optical substrate; 200 - First photoresist; 300 - First hemisphere; 400 - First frustum; 500 - Second photoresist; 600 - Second frustum; 700 - Second hemisphere; 800 - Hemispherical protrusion; 110 - Microlens section; 900 - Micro light-emitting chip; 1000 - Microlens front structure. Detailed Implementation

[0060] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0061] It should be noted that when an element is said to be "fixed" to another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly" on another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0062] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the template description is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0065] The inventors of this invention discovered that micro LED structures have high requirements for lens precision. However, as the etching depth and the number of structures increase, the density of the reactant gas decreases due to the generation of byproduct gas at the etched structure, and the lateral movement of particles after bombardment leads to lateral etching of the sidewalls, as well as a decrease in uniformity, and even the formation of slopes at the bottom of the vertical structure.

[0066] Based on the above issues, such as Figure 1 As shown, some embodiments of the present invention provide a method for fabricating a transparent optical structure, mainly applied to the fabrication of lenses suitable for micro-LED structures, to solve the problem of incomplete fit of phase-shifting surfaces (PSS). The method for fabricating this optical structure includes the following steps:

[0067] Step S100: Obtain an optical substrate and coat the surface of the optical substrate with photoresist.

[0068] The shape of the optical slide 100 can be any of the following: a sheet-like circle, a polygon, a regular polygon, an ellipse, a trapezoid, a letter shape, or an irregular shape. Alternatively, the shape of the optical slide 100 can also be any of the following: a sphere, an ellipsoid, a polygonal prism, or a cylinder.

[0069] Specifically, in this embodiment, the optical carrier 100 has a sheet-like structure, which facilitates the subsequent fabrication of optical structures.

[0070] It should be noted that a phase-shifting surface (PSS) array is a quasi-periodic structure formed by arranging patches or aperture units with different operating states in a two-dimensional rectangular grid. It plays a role in spatially shifting the phase of incident plane electromagnetic waves. By adjusting the operating states of the array units, different phase delays can be formed to achieve the desired phase wavefront.

[0071] Photoresist can be uniformly coated onto the optical carrier 100 by spin coating. High-contrast photoresist can be used.

[0072] Spin coating (or spin coating) is a coating process that relies on the centrifugal force and gravity generated when the workpiece rotates to evenly distribute paint droplets falling on the workpiece surface. Spin coating is only suitable for preparing single-sided coatings on simple planar workpieces, and is mainly used for preparing electron beam tube fluorescent screen coatings, etc. The main advantage of spin coating is that it is easy to obtain coatings with high density and relatively uniform coating thickness. In addition, spin coating is short for spin coating method, which is a commonly used preparation method in organic light-emitting diodes. The main equipment is a spin coater. The spin coating method can include three steps: material preparation, high-speed rotation, and evaporation to form a film. The film thickness is controlled by controlling the spin coating time, rotation speed, drop volume, and the concentration and viscosity of the solution used. In practice, other coating methods can also be used to coat a layer of photoresist, such as blade coating.

[0073] In addition, the photoresist spin-coated on the optical carrier 100 forms a photoresist layer on the surface of the optical carrier 100, and the thickness of the photoresist layer can range from 1 μm to 20 μm. Furthermore, in the various embodiments of the present invention, the micro-LED structure generally refers to an LED structure with a chip size of less than 200 μm, which can be a Mini LED or a Micro LED.

[0074] Step S200: Expose and develop the optical substrate coated with photoresist to obtain photoresist for multiple microlens front structures.

[0075] It should be noted that the photoresist can be exposed and developed according to the preset shape, structure and position to solidify the exposed photoresist, thereby obtaining the preset pattern, so as to provide a reference for subsequent etching and thus improve the etching accuracy.

[0076] In step S300, the etched and developed optical substrate is used to form a microlens portion on the surface of the optical substrate to obtain an optical structure.

[0077] An etching machine is used to etch the image formed on the photoresist after exposure and development onto the optical substrate, so as to etch the image on the photoresist onto the optical substrate and form microlenses on the surface of the optical substrate, thereby obtaining an optical structure.

[0078] like Figure 2 As shown, in some embodiments of the present invention, the method further includes: step S110, obtaining an optical carrier and coating a first photoresist layer on the surface of the optical carrier.

[0079] It should be noted that this can be done by completing the fabrication process of the micro-light-emitting chips on the back side first, and then fabricating the microlens structure on the other side; or it can be done by fabricating the microlens structure first, and then completing the fabrication process of the micro-light-emitting chips. During implementation, positioning marks from the micro-light-emitting chip fabrication process are captured. Typically, the light-emitting chips are fabricated first, followed by the corresponding microlens structure. For example, the micro-light-emitting chip array is fabricated first, and then when fabricating the microlens structure on the opposite side of the fabricated micro-light-emitting chip array, positioning marks from the fabrication process of the micro-light-emitting chip array are captured. This ensures that the microlens structure fabricated on the back side corresponds precisely to the micro-light-emitting chip array. This allows micro-light-emitting chip arrays with different sizes and arrangements of light-emitting chips to obtain corresponding microlens structures, thereby improving the performance of the micro-LED structure including the micro-light-emitting chip array.

[0080] The first photoresist 200 can be uniformly coated on the optical carrier 100 by spin coating. The first photoresist 200 can be a high-contrast photoresist.

[0081] Step S210: Expose and develop the first portion of the first photoresist coated on the optical carrier.

[0082] It is understandable that a hemispherical structure can be formed on a portion of the first photoresist 200 coated on an optical substrate by using an exposure machine and a grayscale exposure plate to expose and develop the first portion of the first photoresist 200 at a first hemispherical 300.

[0083] In addition, an exposure machine and a grayscale exposure plate can be used to expose and develop the first portion of the first photoresist 200 in a first frustum 400, so that a portion of the first photoresist 200 forms a frustum-shaped structure.

[0084] In this embodiment, an exposure machine and a grayscale exposure plate can be used to simultaneously expose and develop the first portion of the first photoresist 200 into a first hemisphere 300 and a first frustum 400, so that a portion of the first photoresist 200 forms a hemisphere structure, while the other portion of the first photoresist 200 forms a frustum structure.

[0085] It should be noted that the first part refers to a portion of the first photoresist 200 spin-coated onto the surface of the optical carrier 100. Specifically, the first part may be one-third or one-half of the first photoresist 200 located on the same side. Alternatively, the first part may be distributed in a ring shape on the first photoresist 200. This first part on the first photoresist 200 may be a designated location on the first photoresist 200, specifically, the designated location may be the area corresponding to the light-emitting area.

[0086] The first portion of the first photoresist 200 is exposed and developed using an exposure machine and a grayscale exposure plate to obtain the first photoresist 200 of the desired shape, in preparation for the next step of etching on the optical substrate 100 in combination with the obtained shape of the first photoresist 200.

[0087] In practice, the UV (ultraviolet, photopolymer exposure) light source emitted by the exposure machine passes through the exposure plate to transfer the pattern onto the first photoresist 200, and the unexposed areas on the first photoresist 200 are developed and preserved by the developing solution to obtain the desired 3D pattern on the first photoresist 200.

[0088] In this embodiment, the exposure machine is an ultraviolet (UV) exposure machine. A UV exposure machine is a device that uses UVA wavelength ultraviolet light to transfer image information from film or other transparent materials to a surface coated with a photosensitive material. Grayscale refers to the level of tonal depth in a black-and-white image, representing the intensity of electromagnetic radiation from ground features. It is a scale for classifying the spectral characteristics of ground features. This facilitates the control of screen brightness corresponding to signal input. It can be understood that grayscale exposure plates are designed based on the different intensities of electromagnetic radiation (reflection or emission) from different materials. Therefore, the degree of light exposure on the grayscale exposure plate varies, resulting in tonal variations between black and white, which constitute the grayscale levels.

[0089] Step S310: Etch the optical substrate coated with the developed first photoresist to transfer the exposed first part of the microlens front structure onto the optical substrate.

[0090] It should be noted that the microlens front structure 1000 includes at least one of a hemisphere, a frustum, and a cone.

[0091] Specifically, in this embodiment, the etching machine can be an ICP (Inductively Coupled Plasma) etching machine. It should be noted that ICP etching is a widely used technique that provides high-rate, high-selectivity, and low-damage etching. Plasma can remain stable under low pressure, thus allowing for better control of the etching morphology.

[0092] Plasma etching is the most common form of dry etching. Its principle is that the gas exposed to the electron region forms plasma, and the resulting ionized gas and the gas that releases high-energy electrons form plasma or ions. When the ionized gas atoms are accelerated by the electric field, they release enough force to tightly bond the material or etch the surface with the surface expulsion force.

[0093] It should be noted that, in this embodiment, ICP etching is performed under vacuum and low pressure. The radio frequency output generated by the ICP RF power supply is sent to the ring coupling coil. A certain proportion of mixed etching gas is coupled to glow discharge to generate high-density plasma. Under the RF action of the lower electrode, these plasmas bombard the surface of the optical carrier 100. The chemical bonds of the semiconductor material in the patterned area of ​​the optical carrier 100 are broken, and volatile substances are generated with the etching gas. These volatile substances are separated from the optical carrier 100 in gaseous form and are extracted from the vacuum tube.

[0094] The optical carrier 100 is etched using an etching machine. The etched shape on the optical carrier 100 can be any one of an ellipsoid, a pyramid, a trapezoid, or a triangle.

[0095] It should be noted that when the first portion of the first photoresist 200 is exposed and developed using an exposure machine and a grayscale exposure plate in step S210, the exposed first hemisphere 300 is transferred to the optical carrier 100 by an etching machine in step S310. That is, hemisphere etching is performed on the optical carrier 100 to form a hemisphere structure on the optical carrier 100, thereby transferring the hemisphere structure on the first photoresist 200 to the optical carrier 100.

[0096] When the first portion of the first photoresist 200 is exposed and developed using an exposure machine and a grayscale exposure plate in step S210, the exposed first frustum 400 is transferred to the optical carrier 100 by an etching machine in step S310. That is, frustum etching is performed on the optical carrier 100 to form a frustum structure on the optical carrier 100, thereby transferring the frustum structure on the first photoresist 200 to the optical carrier 100.

[0097] When the first portion of the first photoresist 200 is simultaneously exposed and developed using an exposure machine and a grayscale exposure plate in step S210, the first hemisphere 300 and the first frustum 400 are simultaneously transferred to the optical carrier 100 by an etching machine in step S310. That is, a hemisphere is etched on a portion of the optical carrier 100, and a frustum is etched on another portion of the optical carrier 100, so as to form a hemisphere structure and a frustum structure on the optical carrier 100, thereby transferring the hemisphere structure and the frustum structure on the first photoresist 200 to the optical carrier 100 at the same time.

[0098] It is understandable that the etching on the optical carrier 100 by the etching machine is based on the shape on the first photoresist 200. That is, the etching machine etches the optical carrier 100 according to the shape of the first photoresist 200, thereby transferring the pattern or design on the first photoresist 200 to the optical carrier 100.

[0099] Specifically, an ICP etching machine bombards the surface of the optical substrate 100 with chlorine gas or ions in a proportional manner to transfer the pattern on the first photoresist 200 onto the optical substrate 100, thereby forming a 3D pattern on the optical substrate 100.

[0100] Step S410: After cleaning away the first photoresist on the surface of the optical carrier, a second photoresist is coated on the etched surface of the optical carrier.

[0101] Specifically, the first photoresist 200 on the surface of the optical carrier 100 obtained in step S310 is cleaned away.

[0102] The specific cleaning steps are as follows: First, the optical substrate 100 is immersed in acetone for 5 to 10 minutes and then ultrasonically cleaned to remove the first photoresist 200 on the surface of the optical substrate 100 by acetone and ultrasonic cleaning.

[0103] Next, the optical slide 100 is immersed in isopropanol for 5 to 10 minutes and then ultrasonically cleaned to remove any residual acetone from its surface. It should be noted that acetone is insoluble in water, therefore isopropanol is used to remove the acetone from the surface of the optical slide 100.

[0104] Finally, the optical carrier 100 is cleaned with deionized water to dissolve the residual isopropanol on the surface of the optical carrier 100 in the water, thereby removing the isopropanol from the surface of the optical carrier 100.

[0105] It should be noted that deionized water is nearly pure water obtained by removing ionic impurities from water using ion exchange resin. Using deionized water to clean the optical substrate 100 improves the cleaning quality.

[0106] Specifically, a layer of high-contrast second photoresist 500 can be uniformly coated on the etched surface of the optical carrier 100 by spin coating. At the same time, a second photoresist 500 layer is formed on the etched surface of the optical carrier 100, and the thickness of the second photoresist 500 layer can range from 1 μm to 20 μm.

[0107] Step S510: Expose and develop the second portion of the second photoresist coated on the optical carrier.

[0108] It should be noted that when the etched surface on the optical carrier 100 is hemispherical, the second part of the second photoresist 500 is exposed and developed using an exposure machine and a grayscale exposure plate to form a 3D second hemisphere 700 on the second part of the second photoresist 500.

[0109] In addition, when the etched surface on the optical carrier 100 is a frustum, the second portion of the second photoresist 500 is exposed and developed using an exposure machine and a grayscale exposure plate to form a 3D second frustum 600 on the second portion of the second photoresist 500.

[0110] In this embodiment, when the etched surface on the optical carrier 100 has both a hemisphere and a frustum, the second portion of the second photoresist 500 is simultaneously exposed and developed using an exposure machine and a grayscale exposure plate to form a 3D second hemisphere 700 and a frustum 600 on the second portion of the second photoresist 500.

[0111] In this embodiment, the orthographic projections of the first part and the second part onto the plane of the optical carrier are misaligned. It should be noted that the misalignment referred to here means that there is no overlap between the orthographic projections of the first part and the second part onto the plane of the optical carrier. This lack of overlap means that there is a gap between the first part and the second part, or that the first part and the second part are in contact with each other.

[0112] Step S610 involves etching the optical substrate coated with the developed second photoresist to transfer the exposed second portion of the microlens front structure onto the optical substrate.

[0113] When the second portion of the second photoresist is exposed and developed in step S510 using an exposure machine and a grayscale exposure plate, the exposed second hemisphere is transferred to the optical carrier 100 in step S610 by an etching machine. That is, hemisphere etching is performed on the optical carrier 100 to form a hemisphere structure on the optical carrier 100, thereby transferring the hemisphere structure on the second photoresist to the optical carrier 100.

[0114] When the second portion of the second photoresist is exposed and developed using an exposure machine and a grayscale exposure plate in step S510, the exposed second frustum is transferred to the optical carrier 100 by an etching machine in step S610. That is, frustum etching is performed on the optical carrier 100 to form a frustum structure on the optical carrier 100, thereby transferring the frustum structure on the second photoresist to the optical carrier 100.

[0115] When the second portion of the second photoresist is simultaneously exposed and developed using an exposure machine and a grayscale exposure plate in step S510, the exposed second hemisphere and the second frustum are simultaneously transferred to the optical carrier 100 by an etching machine in step S610. That is, a hemisphere is etched on a part of the optical carrier 100, and a frustum is etched on another part of the optical carrier 100, so as to form a hemisphere structure and a frustum structure on the optical carrier 100, thereby transferring the hemisphere structure and the frustum structure on the second photoresist to the optical carrier 100 at the same time.

[0116] It is understandable that the etching on the optical substrate 100 by the etching machine is based on the shape on the second photoresist. That is, the etching machine etches the optical substrate 100 according to the shape of the second photoresist, thereby transferring the pattern or design on the second photoresist to the optical substrate 100.

[0117] Specifically, an ICP etching machine bombards the surface of the optical substrate 100 with chlorine gas or ions in a proportional manner to transfer the pattern on the second photoresist to the optical substrate 100, thereby forming a 3D pattern on the optical substrate 100.

[0118] In this embodiment, when the first hemisphere of the first photoresist is exposed and developed by the exposure machine and the grayscale exposure plate respectively, and the second hemisphere of the second photoresist is exposed and developed at the same time, the exposed first hemisphere and the second hemisphere are transferred to the optical substrate by the etching machine, so that the first hemisphere 300 on the optical substrate 100 is connected with the second hemisphere 700 on the optical substrate 100 to form a hemispherical protrusion.

[0119] In this embodiment, when the first frustum is exposed and developed by the exposure machine and the grayscale exposure plate respectively, and the second frustum is exposed and developed by the second photoresist, the exposed first frustum and the second frustum are transferred to the optical substrate by the etching machine, so as to etch the frustum structure on the optical substrate 100 into a triangular structure.

[0120] In this embodiment, when the first photoresist is exposed and developed using an exposure machine and a grayscale exposure plate to form a first frustum and a first hemisphere, and the second photoresist is exposed and developed to form a second frustum and a second hemisphere, the exposed first frustum, second frustum, first hemisphere, and second hemisphere are transferred to an optical substrate by an etching machine to etch the frustum structure on the optical substrate 100 into a triangular structure. At the same time, a hemispherical protrusion 800 is formed in the middle of the optical substrate 100.

[0121] It should be noted that the first and second hemispheres on the optical slide 100 are symmetrical about the junction of the two hemispheres.

[0122] Step S710: Clean away the second photoresist on the surface of the optical carrier to obtain an optical structure with microlenses.

[0123] In this embodiment, the optical structure is obtained by cleaning away the excess second photoresist 500 on the surface of the optical carrier 100.

[0124] Specifically, the optical substrate 100 obtained in step S610 is immersed in acetone for 5 to 10 minutes and then ultrasonically cleaned to remove the first photoresist 200 from the surface of the optical substrate 100 by acetone and ultrasonic cleaning.

[0125] Next, the optical slide 100 is immersed in isopropanol for 5 to 10 minutes and then ultrasonically cleaned to remove any residual acetone from its surface. It should be noted that acetone is insoluble in water, therefore isopropanol is used to remove the acetone from the surface of the optical slide 100.

[0126] Finally, the optical carrier 100 is cleaned with deionized water coated with the developed second photoresist, so as to dissolve the isopropanol remaining on the surface of the optical carrier 100 in the water, thereby cleaning away the isopropanol on the surface of the optical carrier 100 to obtain the optical structure.

[0127] By utilizing exposure and development, a 3D structure (microlens front structure) is fabricated on a high-contrast photoresist coated on an optical substrate. The photoresist from this microlens front structure is then used to etch the optical substrate, overcoming the 2D etching barrier inherent in microlens fabrication. Furthermore, by separating the 3D optical structure into two parts for separate exposure and etching, the desired optical structure is obtained, significantly improving the adaptability of the phase-shifting surface and achieving better compatibility with the fabricated optical chip. This not only simplifies the fabrication process and increases efficiency but also reduces manufacturing costs.

[0128] In some embodiments of the present invention, the optical carrier 100 is a sapphire substrate. Sapphire (Al₂O₃, also known as white sapphire) single crystal is an excellent multifunctional material. It is heat-resistant, has good thermal conductivity, high hardness, infrared transmittance, and good chemical stability. It is widely used in various fields of industry, defense, and scientific research. It is also a versatile single-crystal substrate material, currently the preferred substrate for blue, violet, and white light-emitting diodes (LEDs) and blue lasers (LDs) (requiring the initial epitaxial growth of gallium nitride thin films on a sapphire substrate), and an important superconducting thin film substrate.

[0129] It should be noted that by using secondary exposure and etching, this invention can reduce the ratio between the depth and width of each etching step, thereby improving structural integrity and greatly enhancing the adaptability of the phase-shifting surface. This results in better compatibility with the fabricated optical chip, simplifying the fabrication steps of the light-emitting structure, improving the fabrication efficiency, and reducing the fabrication cost.

[0130] like Figure 17 As shown, in some embodiments of the present invention, the method for fabricating the optical structure includes the following steps:

[0131] Step S110: Obtain an optical substrate and coat the surface of the optical substrate with a first photoresist.

[0132] Specifically, such as Figure 3 and 4 As shown, the first photoresist 200 is stacked on one side of the optical carrier 100 in the thickness direction, wherein the thickness of the first photoresist can be in the range of 1μm to 20μm.

[0133] Preferably, the orthographic projection of the first photoresist onto the plane of the optical carrier completely overlaps.

[0134] Step S201: The first portion of the first photoresist is exposed and developed in the first hemisphere using an exposure machine and a grayscale exposure plate.

[0135] It should be noted that the first hemisphere mentioned here refers to one-quarter of a sphere, meaning that the first hemisphere has both curved and right-angled surfaces.

[0136] like Figure 5 As shown, the first hemisphere 300 is uniformly distributed on the first photoresist 200.

[0137] Step S301: Etching is performed using an etching machine to transfer the exposed first hemisphere onto the optical carrier.

[0138] In step S400, after cleaning away the first photoresist on the surface of the optical carrier, a second photoresist is coated on the etched surface of the optical carrier.

[0139] Step S501: The second portion of the second photoresist is exposed and developed in the second hemisphere using an exposure machine and a grayscale exposure plate.

[0140] Step S601: Etching is performed using an etching machine to transfer the exposed second hemisphere onto the optical carrier.

[0141] like Figure 6 As shown, the number of first hemispheres 300 and second hemispheres 700 etched on the optical carrier 100 is equal, and the depth of the first hemispheres 300 is equal to the depth of the second hemispheres 700.

[0142] Specifically, a first hemisphere 300 and a second hemisphere 700 are joined to form a smooth hemisphere, and the hemisphere is symmetrical about the joint between the first hemisphere 300 and the second hemisphere 700.

[0143] Step S700: Clean away the second photoresist on the surface of the optical substrate to obtain an optical structure with microlenses.

[0144] It should be noted that the optical structure fabricated using the method described in this embodiment is as follows: Figure 7 The optical structure shown.

[0145] like Figure 18 As shown, in some embodiments of the present invention, the method for fabricating the optical structure includes the following steps: Step S110, obtaining an optical carrier and coating a first photoresist layer on the surface of the optical carrier.

[0146] Step S202: The first portion of the first photoresist is exposed and developed using an exposure machine and a grayscale exposure plate in a first frustum configuration.

[0147] like Figure 8 As shown, the first frustum 400 is evenly distributed on the first photoresist 200.

[0148] In step S302, etching is performed using an etching machine to transfer the exposed first frustum onto the optical carrier.

[0149] like Figure 9 As shown, the optical substrate 100 is etched using an etching machine to form a frustum structure on the optical substrate 100.

[0150] In step S400, after cleaning away the first photoresist on the surface of the optical carrier, a second photoresist is coated on the etched surface of the optical carrier.

[0151] like Figure 10 As shown, a second photoresist 500 is coated on an optical carrier 100 with an etched frustum structure.

[0152] Step S502: The second portion of the second photoresist is exposed and developed using an exposure machine and a grayscale exposure plate in a second frustum configuration.

[0153] In step S602, etching is performed using an etching machine to transfer the exposed second frustum onto the optical carrier.

[0154] like Figure 11 As shown, the first frustum 400 and the second frustum 600 partially overlap, and the overlapping part of the first frustum 400 and the second frustum 600 is a triangular structure, so that the etching machine can etch away the overlapping part of the first frustum 400 and the second frustum 600 during the etching process of the optical carrier 100, so as to form a triangular structure on the optical carrier 100.

[0155] Step S700: Clean away the second photoresist on the surface of the optical substrate to obtain an optical structure with microlenses.

[0156] Specifically, the optical structure fabrication method of this embodiment is used to create a structure as shown in the example. Figure 12 The optical structure shown.

[0157] like Figure 19 As shown, in some embodiments of the present invention, the method for fabricating the optical structure includes the following steps: Step S110, obtaining an optical carrier and coating a first photoresist layer on the surface of the optical carrier.

[0158] Step S203: The first portion of the first photoresist is exposed and developed using an exposure machine and a grayscale exposure plate, forming the first hemisphere and the first frustum.

[0159] The positions of the first hemisphere 300 and the first frustum 400 on the first photoresist 200 can be specifically set according to the actual situation. Specifically, in this embodiment, the first hemisphere 300 is located at the center of the exposed and developed image, the first frustum 400 is spaced apart from the first hemisphere 300, and multiple first frustums 400 are arranged around the first hemisphere 300, and the multiple first frustums 400 can be arranged in a matrix or a ring array.

[0160] like Figure 13 As shown, in this embodiment, the hemisphere is located in the middle of the first photoresist 200, and the first frustum 400 is located around the first hemisphere 300.

[0161] In step S303, etching is performed using an etching machine to transfer the exposed first hemisphere and first frustum onto the optical carrier.

[0162] It is understandable that, such as Figure 14As shown, the first hemisphere 300 is located in the middle of the optical carrier 100, and the first frustum 400 is located around the first hemisphere 300 etched on the optical carrier 100.

[0163] In step S400, after cleaning away the first photoresist on the surface of the optical carrier, a second photoresist is coated on the etched surface of the optical carrier.

[0164] Step S503: The second portion of the second photoresist is exposed and developed using an exposure machine and a grayscale exposure plate to create a second hemisphere and a second frustum.

[0165] In step S603, etching is performed using an etching machine to transfer the exposed second hemisphere and second frustum onto the optical carrier.

[0166] like Figure 15 As shown, in this embodiment, the first hemisphere 300 and the second hemisphere 700 etched on the optical carrier 100 are connected to each other to form a hemispherical protrusion. The triangular structure located on the circumference of the hemispherical protrusion is symmetrical with respect to the connection between the first hemisphere 300 and the second hemisphere 700.

[0167] Step S700: Clean away the second photoresist on the surface of the optical substrate to obtain an optical structure with microlenses.

[0168] The optical structure fabricated using the method described in this embodiment is as follows: Figure 16 The optical structure shown.

[0169] It should be noted that the Micro Fresnel lens is obtained by cleaning away the optical carrier 100 obtained in step S703.

[0170] Fresnel lenses, also known as threaded lenses, are mostly thin sheets made of polyolefin material through injection molding, but some are made of glass. One side of the lens surface is smooth, while the other side is engraved with concentric circles of varying sizes. Its texture is designed based on light interference and scattering, as well as relative sensitivity and receiving angle requirements.

[0171] Based on any of the above embodiments, in some embodiments of the present invention, the method for fabricating the optical structure includes obtaining an electron beam exposure machine and replacing the exposure machine and grayscale exposure plate in steps S300 and S700 with the electron beam exposure machine.

[0172] It is understandable that, such as Figure 21 As shown, in this embodiment, the method for fabricating the optical structure includes: step S110, obtaining an optical carrier and coating a layer of first photoresist on the surface of the optical carrier.

[0173] Step S204: The first portion of the first photoresist is exposed and developed using an electron beam exposure machine to the first hemisphere and / or the first frustum.

[0174] In step S300, etching is performed using an etching machine to transfer the exposed first hemisphere and / or first frustum onto an optical carrier.

[0175] In step S400, after cleaning away the first photoresist on the surface of the optical carrier, a second photoresist is coated on the etched surface of the optical carrier.

[0176] Step S504: The second portion of the second photoresist is exposed and developed using an electron beam exposure machine to form a second hemisphere and / or a second frustum.

[0177] In step S600, etching is performed using an etching machine to transfer the exposed second hemisphere and / or second frustum onto an optical carrier.

[0178] Step S700: Clean away the second photoresist on the surface of the optical substrate to obtain an optical structure with microlenses.

[0179] Electron beam lithography, or electron beam lithography, is a process that uses an electron beam to create patterns on a surface; it is an extension of photolithography. The precision of photolithography is affected by the scattering of photons at the wavelength scale. The shorter the wavelength of light used, the higher the precision that photolithography can achieve. According to de Broglie's matter-wave theory, electrons are waves with extremely short wavelengths. Thus, electron beam lithography can achieve precision at the nanometer scale, providing a very useful tool for fabricating nanowires.

[0180] In addition, the electron beam exposure machine prepares nanoscale structures on electron beam photosensitive emulsion. The equipment has an electron acceleration voltage of 100KV, a scanning speed of 12MHz, and multiple substrate stages. Therefore, it has the characteristics of high processing accuracy, high speed, and high degree of automation, thus having relatively high working efficiency.

[0181] This invention reduces etching density through a two-stage etching process, thereby increasing protection of the sidewalls of the optical substrate and reducing the ratio between the depth and width of each etching step, thus improving structural integrity and etching accuracy.

[0182] like Figure 7 , Figure 12 and Figure 16 As shown, some embodiments of the present invention provide an optical structure, which is prepared using the optical structure preparation method described in any of the above embodiments.

[0183] This includes a substrate and a plurality of microlens portions 110 disposed on one side of the substrate in the thickness direction. It should be noted that, in this embodiment, the substrate is the optical carrier described in the above embodiments.

[0184] It is understandable that multiple microlens portions 110 are formed by etching one side of the optical carrier in the thickness direction through optical structure fabrication methods.

[0185] Specifically, the microlens portion 110 described in this embodiment is a frustum and / or hemisphere as described in any of the above embodiments. For example, when the optical structure is entirely hemispherical, the microlens portion 110 is a hemisphere. When the optical structure is entirely frustum-shaped, the microlens portion 110 is a frustum. When the optical structure is a combination of hemispherical and frustum-shaped structures, the microlens portion can refer to either a frustum or a hemisphere.

[0186] The shape of the microlens portion 110 is any one or a combination of two or more of the following: hemispherical, conical, polygonal prism, and oblique prism.

[0187] In this embodiment, the substrate is made of a transparent material.

[0188] like Figure 20 As shown, some embodiments of the present invention provide a light-emitting structure, including the optical structure described in any of the above embodiments, and an optical structure made by the preparation method of the optical structure described in any of the above embodiments.

[0189] Specifically, the optical structure has multiple micro-light-emitting chips on the side opposite to the microlens portion.

[0190] Furthermore, in the thickness direction of the optical structure, at least a portion of the micro-light-emitting chips corresponds one-to-one with the microlens portion.

[0191] It should be noted that when the number of micro-light-emitting chips is greater than the number of microlenses, a portion of the micro-light-emitting chips correspond one-to-one with the microlenses.

[0192] Furthermore, in some embodiments of the present invention, the number of the micro-light-emitting chips 900 is equal to the number of the microlens portions 110, with each micro-light-emitting chip 900 corresponding to one microlens portion 110, thereby improving the accuracy of the light-emitting structure and reducing costs.

[0193] In addition, such as Figure 22 As shown, some embodiments of the present invention provide a method for preparing a light-emitting structure, comprising the following steps:

[0194] Step S120: Obtain the transparent optical structure and the micro-light-emitting chip.

[0195] The optical structure described in any of the above embodiments is an optical structure. Additionally, the micro-light-emitting chip 900 is a micro-LED chip.

[0196] Step S220: The micro-light-emitting chip is positioned on the side of the transparent optical structure opposite to the microlens section to obtain the micro-light-emitting structure.

[0197] Specifically, the number of micro-light-emitting chips 900 is equal to the number of microlenses, and the light-emitting surface of each micro-light-emitting chip 900 faces the microlens.

[0198] Among them, the micro light-emitting chip 900 can be set on the optical structure by mass transfer and other methods.

[0199] In addition, such as Figure 23 As shown, some embodiments of the present invention provide a method for preparing a light-emitting structure, comprising the following steps:

[0200] Step S130: Obtain an optical carrier with multiple micro-light-emitting chips.

[0201] It should be noted that a plurality of micro-light-emitting chips 900 are provided on one side of the optical carrier 100 in the thickness direction. The number and arrangement of the plurality of micro-light-emitting chips 900 are arranged in a pre-set manner to obtain the optical carrier 100 required in this embodiment.

[0202] Step S230: The side of the optical carrier facing away from the plurality of micro-light-emitting chips is processed by any of the above-described methods for preparing a transparent optical structure to obtain a micro-light-emitting structure with a microlens portion corresponding to the micro-light-emitting chip.

[0203] Specifically, the side of the optical carrier 100 facing away from the micro-light-emitting chip 900 is processed by the transparent optical structure preparation method described in any of the above embodiments, thereby forming a plurality of microlens portions 110 on the side of the optical carrier 100 facing away from the micro-light-emitting chip 900, i.e. forming a microlens array, and each microlens portion 110 corresponds to a micro-light-emitting chip 900, thereby obtaining the micro-light-emitting structure.

[0204] It should be noted that, in some embodiments, during the operation of the micro-LED structure, the light is refracted through the interface of the microlens array, and the light is emitted in a straight line in a parallel manner, which collimates the diverging light and has a good light-gathering effect, thereby improving the utilization rate of light.

[0205] This invention provides a micro-light-emitting structure that can be applied to electronic devices to realize XR (Extended Reality) technologies such as AR (Augmented Reality), VR (Virtual Reality), and MR (Mixed Reality). For example, the micro-light-emitting structure can be a projection part of an electronic device, such as a projector or HUD; or it can be a display part of an electronic device, such as a smartphone, smartwatch, laptop, tablet, dashcam, navigator, head-mounted device, or any other device with a display screen; or it can be an illumination part of an electronic device, such as a vehicle or streetlight, or any other device with an illumination component.

[0206] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0207] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0208] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method of making a transparent optical structure, characterized by, The method comprises the following steps: obtaining an optical wafer, and coating photoresist on the surface of the optical wafer; exposing and developing the optical wafer coated with the photoresist to obtain photoresist of a plurality of microlens pre-structures; etching the developed optical wafer to set microlens portions on the surface of the optical wafer to obtain an optical structure; exposing and developing the optical wafer coated with the photoresist to obtain photoresist of a plurality of microlens pre-structures; etching the developed optical wafer to set microlens portions on the surface of the optical wafer to obtain an optical structure, comprising: exposing and developing a first part of the first photoresist coated on the optical wafer; etching the optical wafer coated with the developed first photoresist to transfer the exposed first part of the microlens pre-structure to the optical wafer; after cleaning the first photoresist on the surface of the optical wafer, coating a layer of second photoresist on the etched surface of the optical wafer; exposing and developing a second part of the second photoresist coated on the optical wafer; etching the optical wafer coated with the developed second photoresist to transfer the exposed second part of the microlens pre-structure to the optical wafer; wherein the first part and the second part are mutually staggered in the orthographic projection of the plane in which the optical wafer lies.

2. The method of making a transparent optical structure of claim 1, wherein, The thickness of the first photoresist is equal to the thickness of the second photoresist.

3. The method of producing a transparent optical structure according to any one of claims 1 to 2, characterized in that, The exposure mode comprises at least one of the following: exposing the photoresist by an exposure machine and a gray-scale exposure plate; exposing the photoresist by an electron beam exposure machine.

4. The method of making a transparent optical structure of claim 1, wherein, The microlens pre-structure comprises at least one of a hemisphere, a circular truncated cone, and a pyramid.

5. A transparent optical structure, characterized by The optical structure is prepared by the method of any one of claims 1 to 4.

6. The transparent optical structure of claim 5, wherein, The optical structure comprises a substrate and a plurality of microlens portions arranged on one side of the substrate in the thickness direction of the substrate. The microlens portion is convex, and the shape of the microlens portion is any one of a hemisphere, a cone, a polygonal prism, and an oblique prism, or a combination of two or more thereof.

7. A micro light emitting structure, characterized by The transparent optical structure is prepared by the method of any one of claims 1 to 3. Or the transparent optical structure of any one of claims 4 to 6. The transparent optical structure is provided with a plurality of micro light emitting chips on the side away from the microlens portion. In the thickness direction of the transparent optical structure, at least part of the micro light emitting chips correspond to the microlens portions one by one.

8. The micro light emitting structure of claim 7, wherein, The number of the micro light emitting chips corresponds to the number of the microlens portions, and each of the micro light emitting chips corresponds to one of the microlens portions.

9. A method of fabricating a micro light emitting structure, characterized by, The method comprises the following steps: obtaining an optical wafer provided with a plurality of micro light emitting chips; processing the side of the optical wafer away from the plurality of micro light emitting chips by the method of preparing the transparent optical structure of any one of claims 1 to 4 to obtain a micro light emitting structure provided with microlens portions corresponding to the micro light emitting chips.

10. A method of fabricating a micro light emitting structure, characterized by, The method comprises the following steps: obtaining a transparent optical structure and a micro light emitting chip; correspondingly arranging the micro light emitting chip on the side of the transparent optical structure away from the microlens portion to obtain the micro light emitting structure of claim 7 or 8.

Images