Micro LED Microdisplay Chip and Its Preparation Method

Abstract

This application relates to the technical field of display chips, and provides a Micro LED microdisplay chip and a preparation method thereof. The microdisplay chip includes a driving substrate and a light-emitting structure disposed on the driving substrate; the light-emitting structure includes: a plurality of LED units arranged at intervals on the driving substrate, each LED unit can be separately driven by the driving substrate, and the plurality of LED units have a plurality of LED mesa surfaces corresponding one by one; a first fence structure, the first fence structure has a plurality of first grid holes, the plurality of first grid holes respectively surround the plurality of LED mesa surfaces, and the first fence structure is higher than the plurality of LED units; an optical layer disposed on the first fence structure, and a cavity region is formed at the corresponding first grid hole between the LED mesa surface and the optical layer. The cavity region is formed by a simple process, and the heat generated by the LED unit is reduced from being conducted to the upper light conversion structure, which not only improves the service life of the microdisplay chip, but also reduces the manufacturing cost.

Description

Technical Field

[0001] This application relates to the technical field of display chips, and particularly relates to a Micro LED micro-display chip and a preparation method thereof. Background Art

[0002] Micro-display Micro LED, also known as a micro light-emitting diode, is to integrate an array of micron-level LED light-emitting units on an active addressing driving substrate to achieve individual control and lighting, thereby outputting a display image. Full-color micro-displays have a wide range of application fields, especially near-eye displays (including AR, VR, etc.).

[0003] In the traditional full-color micro-display form where a light conversion structure is directly set on the light-emitting structure, since the heat generated by the LED unit is directly conducted to the light conversion structure, accelerating the aging and failure of the light conversion structure, the lifespan of the full-color micro-display device is limited to a certain extent.

[0004] In order to limit the transfer of heat generated by the LED unit to the light conversion structure, Chinese patent document CN119050126A discloses a display device and a forming method thereof. An insulating structure including an overhead unit is provided on a planarization layer. To form the overhead unit, a sacrificial layer is formed on the planarization layer, a preset number of holes are formed in the sacrificial layer, the holes penetrate the sacrificial layer to expose the surface of the planarization layer, a support leg is formed in the hole, and an overhead layer is formed on the sacrificial layer. By removing the sacrificial layer, the overhead layer is suspended on the support leg. In order to form an insulating cavity inside the overhead unit, a heat-conducting layer is sealed between adjacent overhead units to seal the side of the overhead unit. Chinese patent document CN119050126A forms a complex overhead unit above the planarization layer, the overall thickness of the micro-display device structure is relatively large, and the preparation process is complex, which is not conducive to the development of chip products towards small size and low cost.

[0005] Chinese patent document CN119050236A discloses a MicroLED micro-display chip. A plurality of groups of through holes are formed in the first transmissive and reflective layer, and each group of through holes is circumferentially arranged around the edge of the corresponding grid hole. The through holes penetrate the first transmissive and reflective layer and extend into the grid hole, so that the etching solution can flow into the grid hole through the through holes to etch and hollow out the sacrificial layer in the grid hole through the etching solution. By filling the through holes with heat-conducting metal units, a cavity with a central control structure can be formed between the first transmissive and reflective layer and the LED unit. In order to form a cavity in Chinese patent CN119050236A, not only the integrity of the first transmissive and reflective layer needs to be broken to form a plurality of groups of through holes in the first transmissive and reflective layer, but also the through holes need to be closed with heat-conducting metal units to form a cavity. The above complex process greatly increases the production and manufacturing cost. Due to the extremely high precision requirements of the above complex process, the yield is low. Summary of the Invention

[0006] To solve the above problems, the present application provides a Micro LED microdisplay chip and a manufacturing method thereof. A cavity structure is formed on the LED unit through a simple process, reducing the heat conduction of the LED unit to the light conversion structure, improving the service life of the microdisplay chip, and reducing the manufacturing cost.

[0007] The present application adopts the following technical solutions:

[0008] In a first aspect, a Micro LED microdisplay chip is provided, including: a driving substrate and a light-emitting structure disposed on the driving substrate;

[0009] The light-emitting structure includes: a plurality of LED units, a first fence structure, and an optical layer;

[0010] The plurality of LED units are arranged at intervals on the driving substrate, and each LED unit can be separately driven by the driving substrate. The plurality of LED units have a plurality of LED mesa surfaces corresponding one by one;

[0011] The first fence structure has a plurality of first grid holes, and the plurality of first grid holes respectively surround the plurality of LED mesa surfaces. The first fence structure is higher than the plurality of LED units;

[0012] The optical layer is disposed on the first fence structure, and a cavity region is formed at the corresponding first grid hole between the LED mesa surface and the optical layer.

[0013] Optionally, the first fence structure includes: a first light-blocking matrix and a first reflective layer disposed on the surface of the first light-blocking matrix;

[0014] The first light-blocking matrix has a plurality of first grid holes;

[0015] The first reflective layer is disposed at least on the side walls of the first grid holes.

[0016] Optionally, the optical layer includes: a transparent transition layer disposed on the first fence structure and a transmissive-reflective layer disposed on the transparent transition layer;

[0017] The optical layer is used to transmit the light of the plurality of LED units.

[0018] Optionally, the transparent transition layer is provided with via holes at positions corresponding to each first grid hole.

[0019] Optionally, the transmissive-reflective layer is a distributed Bragg reflector.

[0020] Optionally, the material of the transparent transition layer is a transparent inorganic oxide.

[0021] Optionally, the diameter of the via hole is less than 0.5 μm.

[0022] Optionally, the microdisplay chip further includes: a light conversion structure disposed on the optical layer;

[0023] The light conversion structure includes: a second barrier structure and a plurality of light conversion units;

[0024] The second barrier structure has a plurality of second grid holes, and the plurality of second grid holes correspond to the plurality of first grid holes one by one;

[0025] The plurality of light conversion units are respectively disposed in the plurality of second grid holes.

[0026] Optionally, the second barrier structure includes: a second light-blocking matrix and a second reflective layer disposed on the surface of the second light-blocking matrix;

[0027] The second light-blocking matrix has a plurality of second grid holes;

[0028] The second reflective layer is disposed at least on the side walls of the second grid holes.

[0029] Optionally, the plurality of light conversion units at least include: a first light conversion unit and a second light conversion unit;

[0030] The first light conversion unit converts the light passing through the optical layer into first-color light;

[0031] The second light conversion unit converts the light passing through the optical layer into second-color light.

[0032] Optionally, the plurality of light conversion units further include: a transparent unit;

[0033] The transparent unit transmits the light passing through the optical layer.

[0034] Optionally, the plurality of light conversion units further include: a third light conversion unit;

[0035] The third light conversion unit converts the light passing through the optical layer into third-color light.

[0036] In a second aspect, a method for manufacturing a Micro LED microdisplay chip is provided, including:

[0037] Providing a driving substrate and forming a light-emitting structure on the driving substrate;

[0038] Wherein, forming the light-emitting structure on the driving substrate includes:

[0039] Forming a plurality of LED units; wherein, the plurality of LED units are arranged spaced apart from each other on the driving substrate, and each LED unit can be separately driven by the driving substrate, and the plurality of LED units have a plurality of LED mesa surfaces corresponding one by one;

[0040] Form a first fence structure; wherein, the first fence structure has a plurality of first grid holes, the plurality of first grid holes respectively surround a plurality of LED mesa surfaces, and the first fence structure is higher than the plurality of LED units;

[0041] Form an optical layer; wherein, the optical layer is formed on the first fence structure, and a cavity region is formed at the corresponding first grid hole between the LED mesa surface and the optical layer;

[0042] Wherein, forming the optical layer includes:

[0043] Perform planarization treatment on the first fence structure using a filler;

[0044] Form a transparent transition material layer on the planarized first fence structure;

[0045] Etch the position of the transparent transition material layer corresponding to each first grid hole to form a via hole, and obtain a transparent transition layer;

[0046] Through the via hole, remove the filler between each LED mesa surface and the transparent transition layer at the corresponding first grid hole;

[0047] Form a transmissive and reflective layer on the transparent transition layer.

[0048] Optionally, forming the first fence structure includes:

[0049] Form a first light-blocking matrix material layer on the plurality of LED units;

[0050] Etch the first light-blocking matrix material layer to form a plurality of first grid holes surrounding the plurality of LED mesa surfaces, and obtain a first light-blocking matrix;

[0051] Form a first reflective material layer on the plurality of LED mesa surfaces and the first light-blocking matrix;

[0052] Etch the first reflective material layer to form a first reflective layer at least on the sidewalls of the first grid holes.

[0053] Optionally, the method further includes:

[0054] Form a light conversion structure;

[0055] Wherein, forming the light conversion structure includes:

[0056] Form a second fence structure on the optical layer; wherein, the second fence structure has a plurality of second grid holes, and the plurality of second grid holes correspond to the plurality of first grid holes one by one;

[0057] Form a plurality of light conversion units in the plurality of second grid holes.

[0058] Optionally, forming the second fence structure on the optical layer includes:

[0059] Form a second light-blocking matrix material layer on the optical layer;

[0060] Etch the second light-blocking matrix material layer to form a plurality of second grid holes corresponding one-to-one to the first grid holes, obtaining a second light-blocking matrix;

[0061] Form a second reflective material layer on the optical layer and the second light-blocking matrix;

[0062] Etch the second reflective material layer to form a second reflective layer at least on the sidewalls of the second grid holes.

[0063] Optionally, form a plurality of light conversion units in the plurality of second grid holes, including:

[0064] Fill the plurality of second grid holes with a light conversion material; wherein, the light conversion material at least includes: a first light conversion material and a second light conversion material;

[0065] Fill a part of the second grid holes with the first light conversion material to form a first light conversion unit to convert the light passing through the optical layer into first-color light;

[0066] Fill a part of the second grid holes with the second light conversion material to form a second light conversion unit to convert the light passing through the optical layer into second-color light.

[0067] The above at least one technical solution adopted in this application can achieve the following beneficial effects:

[0068] The chip provided in this application includes: a driving substrate and a light-emitting structure disposed on the driving substrate; the light-emitting structure includes: a plurality of LED units arranged at intervals on the driving substrate, each LED unit can be separately driven by the driving substrate, and the plurality of LED units have a plurality of LED mesa corresponding one-to-one; a first fence structure, the first fence structure has a plurality of first grid holes, the plurality of first grid holes respectively surround the plurality of LED mesa, and the first fence structure is higher than the plurality of LED units; an optical layer disposed on the first fence structure, and a cavity region is formed at the corresponding first grid hole between the LED mesa and the optical layer.

[0069] In the Micro LED microdisplay chip proposed in this application, a cavity region is formed at the corresponding first grid hole between the LED mesa and the optical layer. The air in the cavity region has extremely low thermal conductivity (in a closed state, the thermal conductivity of air is only 0.024W / m·K), reducing the heat generated by the LED unit from being conducted to the upper light conversion structure, and effectively improving the service life of the Micro LED microdisplay chip.

[0070] The Micro LED microdisplay chip proposed in this application can tightly enclose a cavity region through the first grid holes and the optical layer. The manufacturing process is simple and does not require excessive complex precision machining, resulting in a relatively high product yield.

[0071] The Micro LED microdisplay chip proposed in this application has a lower production cost and is suitable for large-scale mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The drawings described herein are used to provide a further understanding of this application and form a part of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0073] Figure 1 Showing a schematic structural diagram of a Micro LED microdisplay chip according to an embodiment of this application;

[0074] Figure 2 Showing a schematic structural diagram of a Micro LED microdisplay chip according to another embodiment of this application;

[0075] Figure 3 Showing a schematic flowchart of a preparation method of a Micro LED microdisplay chip according to an embodiment of this application;

[0076] Figure 4 Showing a schematic structural diagram after forming a plurality of LED units according to an embodiment of this application;

[0077] Figure 5 Showing a schematic structural diagram after forming a first light-blocking matrix material layer according to an embodiment of this application;

[0078] Figure 6 Showing a schematic structural diagram of obtaining a first light-blocking matrix according to an embodiment of this application;

[0079] Figure 7 Showing a schematic structural diagram after forming a first reflective material layer according to an embodiment of this application;

[0080] Figure 8 Showing a schematic diagram after forming a first reflective layer according to an embodiment of this application;

[0081] Figure 9 Showing a schematic structural diagram after planarization processing according to an embodiment of this application;

[0082] Figure 10 Showing a schematic structural diagram after forming a transparent transition material layer according to an embodiment of this application;

[0083] Figure 11Schematic structural diagram after obtaining a transparent transition layer according to an embodiment of the present application;

[0084] Figure 12 Schematic structural diagram after filler removal according to an embodiment of the present application;

[0085] Figure 13 Schematic structural diagram after forming a transmissive and reflective layer according to an embodiment of the present application;

[0086] Figure 14 Schematic structural diagram after forming a second fence structure according to an embodiment of the present application;

[0087] Figure 15 Schematic structural diagram after forming a plurality of light conversion units according to an embodiment of the present application;

[0088] Figure 16 Another schematic structural diagram after forming a plurality of light conversion units according to an embodiment of the present application. Detailed implementation manners

[0089] Exemplary embodiments of the present application will be described in more detail below. However, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be fully conveyed to those skilled in the art.

[0090] The disclosure of the present invention provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and settings of specific examples are described in the present invention. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0091] Generally, terms can be understood at least in part in accordance with their usage in the present invention. For example, the term "one or more" used in the present invention can be understood at least in part in accordance with the present invention, and can be used to describe any component, structure, or feature in the singular form, or can be used to describe a combination of components, structures, or features in the plural form. Similarly, terms such as "a", "an", or "the" can also be understood to convey singular usage or plural usage at least in part in accordance with the present invention. Additionally, the term "based on..." can be understood as not necessarily intended to convey a set of exclusive factors, but rather can alternatively, at least in part depending on the context, allow for additional factors that do not necessarily have to be explicitly described.

[0092] It should be noted that in the description of the present application, the meanings of terms such as "on", "above", "over", "upward of" should be interpreted in the broadest sense, meaning that the description containing these terms is interpreted as "a component can be disposed on another component in a directly contacting manner, or there can be an intermediate component or layer between the components".

[0093] For ease of description, the present application may also use spatial relative terms such as "under", "below", "beneath", "downward of", "upper", "lower", etc. to describe the relationship between one component and another component shown in the drawings. In addition to the orientations described in the figures, the spatial relative terms are also intended to cover different orientations of the device during use or operation. The device can be oriented in other ways, and the spatial relative descriptions used in the present application can be correspondingly interpreted in the same way.

[0094] Figure 1 The structural schematic diagram of the Micro LED microdisplay chip proposed in an embodiment of the present application is shown. In Figure 1 the horizontal direction can correspond to the extension direction of the cross-section of the Micro LED microdisplay chip, and the vertical direction can correspond to the ideal light beam propagation direction of the Micro LED microdisplay chip.

[0095] Referring to Figure 1 , the microdisplay chip of this embodiment can include: a driving substrate 1 and a light-emitting structure 2 disposed on the driving substrate 1.

[0096] The light-emitting structure 2 includes: a plurality of LED units 21, a first fence structure 22, and an optical layer 23. The plurality of LED units 21 are arranged at intervals on the driving substrate 1, and each LED unit 21 can be individually driven by the driving substrate 1 respectively. The plurality of LED units 21 have a plurality of LED mesa surfaces that correspond one by one. The first fence structure 22 has a plurality of first grid holes, and the plurality of first grid holes respectively surround the plurality of LED mesa surfaces. The first fence structure 22 is higher than the plurality of LED units 21. The optical layer 23 is disposed on the first fence structure 22, and a cavity region is formed at the corresponding first grid hole between the LED mesa surface and the optical layer 23.

[0097] The driving substrate 1 may include a substrate 11, a driving circuit, and a plurality of contacts connected to the driving circuit. Among them, the driving substrate 1 may be provided with a circuit layer including a silicon-based CMOS (Complementary Metal Oxide Semiconductor) backplane, a TFT glass substrate, or a thin-film field-effect transistor, etc., to constitute the driving circuit. The material of the substrate 11 may include semiconductor materials such as silicon, silicon carbide, gallium nitride, germanium, gallium arsenide, cobalt phosphide, etc.; it may also include non-conductive materials such as glass, plastic, sapphire wafers, etc. The driving substrate 1 can be bonded to each LED unit 21 through the contacts, and each LED unit 21 can be integrally disposed above the corresponding contact.

[0098] The plurality of LED units 21 can be arranged on the driving substrate 1 in a regular or irregular manner as the pixels of the microdisplay chip. The driving substrate 1 may refer to the control panel of the plurality of LED units 21. The driving substrate 1 generates a driving signal based on the image to be displayed and applies it to the plurality of LED units 21, so that each LED unit 21 independently emits light in response to the driving signal.

[0099] The LED unit 21 can be a micro light-emitting diode or a micro organic light-emitting diode. Among them, the micro light-emitting diode is formed based on an inorganic semiconductor material. For example, the inorganic semiconductor material can be gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium indium phosphide, etc. The micro organic light-emitting diode is formed based on an organic material. For example, the organic material can be small molecules, polymers, phosphorescent materials, etc.

[0100] Each LED unit 21 has an LED mesa surface, and the LED mesa surface can be in a trapezoidal structure. That is, the side wall of the LED mesa surface can be an inclined surface, and the angle between the side wall of the LED mesa surface and the top surface of the LED mesa surface can be an obtuse angle, so as to improve the light condensing effect of the LED unit 21. Of course, the LED mesa surface can also be in a columnar structure. At this time, the angle between the side wall of the LED mesa surface and the top surface of the LED mesa surface is a right angle.

[0101] The Micro LED microdisplay device can be a common cathode structure, or a common anode structure, or independent of each other.

[0102] In some alternative embodiments, each LED unit 21 may include a first doped semiconductor layer 211, a light-emitting layer 212, and a second doped semiconductor layer 213 that are stacked. A passivation layer 214 coats the light-emitting surface and the side surfaces of each LED unit 21 and has an opening on the light-emitting surface of each LED unit 21. At the same time, the passivation layer 214 exposes the contacts of the driving substrate 1. Each LED unit 21 further includes a first electrode 216 and a second electrode 217. A bonding layer 215 may also be included between the first electrode 216 and the first doped semiconductor layer 211. The first doped semiconductor layer 211 is connected to the corresponding first contact 13 of the driving substrate 1 through the bonding layer 215 and the first electrode 216, and the second doped semiconductor layer 213 is connected to the corresponding second contact 12 of the driving substrate 1 through the second electrode 217.

[0103] When the first electrode 216 of each LED unit 21 is a common electrode, the Micro LED microdisplay device is a common anode structure; when the second electrode 217 of each LED unit 21 is a common electrode, the Micro LED microdisplay device is a common cathode structure. Figure 1 The situation shown is a common anode structure.

[0104] The first doped semiconductor layer 211 can be a p-type GaN or InGaN layer formed by doping or ion implantation, etc. The first doped semiconductor layer 211 can be a multi-layer structure. The second doped semiconductor layer 213 can be an n-type GaN or InGaN layer formed by doping or ion implantation, etc. The second doped semiconductor layer 213 can also be a multi-layer structure. The light-emitting layer 212 is a layer that outputs light of a specific wavelength based on the recombination of holes provided by the first doped semiconductor layer 211 and electrons provided by the second doped semiconductor layer 213. The light-emitting layer 212 can have a single quantum well structure or a multi-quantum well (MQW) structure, and the well layer and the barrier layer can also be alternately stacked.

[0105] The material of the passivation layer 214 can include inorganic materials or organic materials. Inorganic materials can include, but are not limited to, any one or a combination of several of silicon dioxide, aluminum oxide, zirconium dioxide, titanium dioxide, silicon nitride, and hafnium oxide; organic materials include any one or a combination of several of black matrix photoresist, color filter photoresist, polyimide, bank photoresist, overcoat photoresist, near-ultraviolet negative photoresist, and benzocyclobutene.

[0106] The materials of the first electrode 216 and the second electrode 217 can be metal materials or metal alloy materials, including indium tin oxide, chromium, platinum, gold, aluminum, germanium, tin, indium, copper, or titanium, etc.

[0107] A first fence structure 22 is provided around the plurality of LED tables. The first fence structure 22 has a plurality of first grid holes corresponding to the LED tables one by one. That is, according to the arrangement of the plurality of LED units 21, the plurality of first grid holes can be arranged in a regular or irregular manner. In order to improve the uniformity of light emission of each LED unit 21, each LED unit 21 can be arranged at the center of the corresponding first grid hole.

[0108] The side wall of the first grid hole may be an inclined surface, that is, the angle between the side wall of the first grid hole and the top surface of the first fence structure 22 is an obtuse angle. Figure 1 As shown in the direction away from the driving substrate 1, the cross-sectional size of the first grid hole can gradually increase. Generally, the cross section can be a circular cross section or a square cross section, and of course, the cross section can also be an irregular cross section. The structure of the first grid hole can be a bowl-shaped structure or a trumpet-shaped structure, so that the emitted light of the LED unit 21 can be collimated. When the side wall of the LED table is set as an inclined surface and the side wall of the first grid hole is also set as an inclined surface, the light can be reflected multiple times on the inclined surfaces of the two, thereby improving the luminous brightness of the LED unit 21.

[0109] The height of the first fence structure 22 is higher than the plurality of LED units 21. In other words, the height of the top surface of the first fence structure 22 is higher than the height of the top surface of each LED unit 21.

[0110] In some optional embodiments, the first fence structure 22 includes: a first light-blocking substrate 221 and a first light-reflecting layer 222 disposed on the surface of the first light-blocking substrate 221. The first light-blocking substrate 221 has a plurality of first grid holes. The first light-reflecting layer 222 is at least disposed on the sidewalls of the first grid holes.

[0111] The first fence structure 22 can be formed by using a first light-blocking matrix material. The first light-blocking matrix material is provided with a first grid hole at a position corresponding to each LED unit 21, and a first light-reflecting layer 222 is provided at least on the side wall of the first grid hole. The first light-reflecting layer 222 can also be provided on the top surface of the first light-blocking matrix 221.

[0112] The material of the first light-blocking substrate 221 may include, but is not limited to, organic resin, organic black matrix photoresist, color filter photoresist or polyimide, etc. The material of the first light-reflecting layer 222 may include, but is not limited to, organic material or inorganic material. The organic material may be a highly reflective organic coating, and the inorganic material may be a metal material such as aluminum, copper, silver, etc.

[0113] The first reflective layer 222 in the first fence structure 22 can effectively prevent the light leakage from the side walls of each LED unit 21, thereby effectively preventing the light crosstalk between adjacent LED units 21. At the same time, the first fence structure 22 also plays a role in heat conduction, preventing the heat generated by the LED material from concentrating and conducting to the phosphor material.

[0114] In some alternative embodiments, an etch stop layer may be covered on the plurality of LED units 21 to prevent etch damage to the plurality of LED mesa surfaces.

[0115] The etch stop layer may be a continuous film structure and is located between the first fence structure 22 and the plurality of LED units 21. The etch stop layer can transmit the light emitted by the plurality of LED units 21, so the etch stop layer should have sufficient transparency. Generally, the material of the etch stop layer may include, but is not limited to, silicon dioxide, silicon nitride, or aluminum oxide, etc.

[0116] An optical layer 23 is provided on the first fence structure 22. For each LED unit 21, its LED mesa surface, the optical layer 23, and the corresponding first grid hole enclose a sealed cavity region. The air in this cavity region has extremely low thermal conductivity. In a sealed state, the thermal conductivity of air is only 0.024 W / m·K. Therefore, through the sealed cavity region, the heat generated by the LED material is reduced from being conducted to the phosphor material above, effectively improving the service life of the Micro LED microdisplay chip.

[0117] In some alternative embodiments, the optical layer 23 includes: a transparent transition layer 231 provided on the first fence structure 22 and a transmissive reflective layer 232 provided on the transparent transition layer 231. The optical layer 23 is used to transmit the light of the plurality of LED units 21.

[0118] In order to form a sealed cavity region between the optical layer 23 and the LED mesa surface at the corresponding first fence hole, it is necessary to planarize the first fence structure 22 with a filler 233 before forming the optical layer 23, and then remove the filler 233 during the process of forming the optical layer 23 to form a cavity structure.

[0119] Therefore, after the first fence structure 22 is planarized, a transparent transition layer 231 is formed on the planarized first fence structure 22, vias are etched at the positions of the transparent transition layer 231 corresponding to each first grid hole, and after removing the filler 233 through the vias, a transmissive reflective layer 232 is formed on the transparent transition layer 231, thereby realizing a sealed cavity structure. That is, the transparent transition layer 231 opens vias at the positions corresponding to each first grid hole.

[0120] The material of the transparent transition layer 231 can be a transparent inorganic oxide material, such as silicon dioxide, aluminum oxide, etc. At the same time, the thickness of the transparent transition layer 231 can be made as thin as possible.

[0121] In order to balance the functional requirements of removing the filler 233 and supporting the transmissive reflective layer 232, the diameter of the via hole is not greater than 0.5 μm. The via hole can be opened at the center position of the transparent transition layer 231 corresponding to each first fence hole.

[0122] The transmissive reflective layer 232 can be a Distributed Bragg Reflector (DBR) layer. The distributed Bragg reflector layer can be composed of multiple alternately stacked materials with different refractive indices. The materials used for the transmissive reflective layer 232 are usually semiconductor materials, such as but not limited to silicon, indium nitride, gallium nitride, aluminum gallium nitride, and iron nickel phosphide, etc. These semiconductor materials have different refractive indices. By stacking them together according to a specific design, the reflection of light with a specific wavelength can be achieved. By adjusting the number of layers and composition of the materials, the transmission of light with different wavelengths can be achieved.

[0123] The function of the optical layer 23 includes transmitting the light emitted by multiple LED units 21. And in the case where the following microdisplay chip further includes a light conversion structure 3 disposed on the optical layer 23, the function of the optical layer 23 further includes reflecting the light whose color is converted by the light conversion structure 3.

[0124] Figure 2 The structural schematic diagram of the Micro LED microdisplay chip proposed in another embodiment of the present application is shown.

[0125] Refer to Figure 2 , on the basis of the microdisplay chip proposed in the previous embodiment, the microdisplay chip of this embodiment further includes: a light conversion structure 3 disposed on the optical layer 23. The light conversion structure 3 includes: a second fence structure 31 and multiple light conversion units 32. The second fence structure 31 has multiple second grid holes, and the multiple second grid holes correspond to the multiple first grid holes one by one. The multiple light conversion units 32 are respectively disposed in the multiple second grid holes.

[0126] The second fence structure 31 has multiple second grid holes corresponding to the first grid holes one by one. That is, according to the arrangement manner of the multiple first grid holes, the multiple second grid holes can be arranged in a regular or irregular manner.

[0127] The side wall of the second grid hole can be an inclined surface, that is, the included angle between the side wall of the second grid hole and the top surface of the second fence structure 31 is an obtuse angle. Refer to Figure 2In the direction away from the driving substrate 1 shown, the cross-sectional dimension of the second grid hole can gradually increase. Generally, the cross-section can be a circular cross-section or a square cross-section. Of course, the cross-section can also be an irregular cross-section. The structure of the second grid hole can be a bowl-shaped structure or a horn-shaped structure.

[0128] In some alternative embodiments, the second fence structure 31 includes: a second light-blocking substrate 311 and a second reflective layer 312 disposed on the surface of the second light-blocking substrate 311. The second light-blocking substrate 311 has a plurality of second grid holes. The second reflective layer 312 is disposed at least on the side walls of the second grid holes.

[0129] The second fence structure 31 can be formed by using the second light-blocking substrate material. The second grid holes are formed at positions corresponding to each of the first grid holes in the second light-blocking substrate material, and the second reflective layer 312 is disposed at least on the side walls of the second grid holes. The second reflective layer 312 can also be disposed on the top surface of the second light-blocking substrate 311.

[0130] The material of the second light-blocking substrate 311 can include, but is not limited to, organic resin, organic black matrix photoresist, color filter photoresist, or polyimide, etc. The material of the second reflective layer 312 can include, but is not limited to, organic materials or inorganic materials. The organic material can be a high-reflection organic coating, and the inorganic material can be a metal material such as aluminum, copper, silver, etc.

[0131] The second reflective layer 312 in the second fence structure 31 can effectively prevent the light entering the light conversion unit 32 from affecting the light of the adjacent light conversion unit 32, reduce the crosstalk between each other, and improve the display effect.

[0132] In a plurality of second grid holes, a plurality of light conversion units 32 are respectively disposed. So that each light conversion unit 32 is correspondingly disposed on one LED unit 21. Each light conversion unit 32 at least fills part or all of the corresponding second grid holes.

[0133] In some alternative embodiments, the plurality of light conversion units 32 at least include: a first light conversion unit 321 and a second light conversion unit 322. The first light conversion unit 321 converts the light passing through the optical layer 23 into first color light; the second light conversion unit 322 converts the light passing through the optical layer 23 into second color light.

[0134] Among the plurality of light conversion units 32, some light conversion units 32 are the first light conversion unit 321, and some light conversion units 32 are the second light conversion unit 322. That is to say, the first light conversion unit 321 and the second light conversion unit 322 are respectively disposed in different second grid holes.

[0135] The materials of the light conversion unit 32 include photoresist and wavelength conversion particles, and the wavelength conversion particles can be but are not limited to quantum dots and / or phosphors. The photoresist includes but is not limited to Overcoat, SU8 (near-ultraviolet negative photoresist), benzocyclobutene (BCB), etc., and can also be silicon dioxide, aluminum oxide, silicon nitride, etc. The phosphor can be yttrium aluminum garnet, cerium phosphor, (oxy)nitride phosphor, silicate phosphor, and Mn 4+ activated fluoride phosphor, etc. The quantum dots can include one or a combination of more than one of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, ZnSeS, ZnSe, CuInS, CuInSe, InP, InZnP, and perovskite quantum dots, etc.

[0136] The light emitted by the LED unit 21 enters the first light conversion unit 321 after passing through the optical layer 23 and is converted into first-color light within the first light conversion unit 321. The first-color light can be red light. At this time, the first light conversion unit 321 uses a red wavelength conversion material. The light emitted by the LED unit 21 enters the second light conversion unit 322 after passing through the optical layer 23 and is converted into second-color light within the second light conversion unit 322. The second-color light can be green light. At this time, the second light conversion unit 322 uses a green wavelength conversion material.

[0137] In some alternative embodiments, the plurality of light conversion units 32 further includes: a transparent unit 324; the transparent unit 324 transmits the light passing through the optical layer 23.

[0138] In some cases, the light emitted by the LED unit 21 is blue light. At this time, it is only necessary for the transparent unit 324 to transmit the blue light emitted by the LED unit 21. Therefore, the transparent unit 324 is disposed in the second grid hole where the first light conversion unit 321 and the second light conversion unit 322 are not provided to directly transmit the blue light emitted by the LED unit 21.

[0139] In some alternative embodiments, the plurality of light conversion units 32 further includes: a third light conversion unit 323; the third light conversion unit 323 converts the light passing through the optical layer 23 into third-color light.

[0140] In some cases, the light emitted by the LED unit 21 is not blue light. At this time, the light emitted by the LED unit 21 enters the third light conversion unit 323 after passing through the optical layer 23 and is converted into third-color light within the third light conversion unit 323. The third-color light can be blue light. At this time, the third light conversion unit 323 uses a blue wavelength conversion material.

[0141] The first color light, the second color light, and the third color light are all different. The first color light, the second color light, and the third color light can also be set to other color lights according to actual needs. By setting multiple light conversion units 32, full-color display of the MicroLED microdisplay chip is achieved.

[0142] Figure 3 FIG. shows a schematic flow chart of a method for fabricating a Micro LED microdisplay chip according to an embodiment of the present application. Referring to Figure 3 , the fabrication method proposed by the present application includes the following steps:

[0143] Step S1, providing a driving substrate 1;

[0144] Step S2, forming a light-emitting structure 2 on the driving substrate 1.

[0145] Among them, step S2, forming a light-emitting structure 2 on the driving substrate 1, includes:

[0146] Step S21, forming a plurality of LED units 21; wherein, the plurality of LED units 21 are arranged at intervals on the driving substrate 1, and each LED unit 21 can be individually driven by the driving substrate 1 respectively, and the plurality of LED units 21 have a plurality of LED mesa surfaces corresponding one by one;

[0147] Step S22, forming a first fence structure 22; wherein, the first fence structure 22 has a plurality of first grid holes, the plurality of first grid holes respectively surround the plurality of LED mesa surfaces, and the first fence structure 22 is higher than the plurality of LED units 21;

[0148] Step S23, forming an optical layer 23; wherein, the optical layer 23 is formed on the first fence structure 22, and a cavity region is formed at the corresponding first grid hole between the LED mesa surface and the optical layer 23; wherein, forming the optical layer 23 includes: flattening the first fence structure 22 with a filler 233; forming a transparent transition material layer 231a on the flattened first fence structure 22; etching the position of the transparent transition material layer 231a corresponding to each first grid hole to form a via hole, obtaining a transparent transition layer 231; removing the filler 233 at the corresponding first grid hole between each LED mesa surface and the transparent transition layer 231 through the via hole; forming a transmissive and reflective layer 232 on the transparent transition layer 231.

[0149] Figures 4 to 16 FIG. shows schematic diagrams of different stages in the fabrication process of the Micro LED microdisplay chip. Referring to Figures 4 to 16 , the method for fabricating the Micro LED microdisplay chip is introduced in detail.

[0150] Figure 4The structural schematic diagram after forming a plurality of LED units 21 is shown. In some embodiments of the present application, refer to Figure 4 , forming a plurality of LED units 21 includes: forming an LED epitaxial layer on a driving substrate 1; etching the LED epitaxial layer according to the MESA pattern designed by a patterning mask. An intermediate is formed; a passivation layer 214 is formed on the sidewall of the intermediate; a second electrode 217 is formed on the passivation layer 214, and the second electrode 217 connects the top surface of the LED epitaxial layer and the second contact 12 of the driving substrate 1, thereby forming a plurality of LED units 21.

[0151] A substrate is provided, and an LED epitaxial layer is grown on the substrate, and a first bonding layer is formed on the LED epitaxial layer. The first bonding layer can be used to bond the LED epitaxial layer on the substrate to the driving substrate 1 proposed hereinafter.

[0152] A driving substrate 1 is provided. The driving substrate 1 can be provided with a circuit layer including a silicon-based CMOS backplane, a TFT glass substrate, or a thin-film field-effect transistor, etc., to constitute a driving circuit. The driving substrate 1 further includes a plurality of contacts connected to the driving circuit. The plurality of contacts include a first contact 13 and a second contact 12. A first electrode 216 and a second bonding layer are formed on the driving substrate 1. The first electrode 216 is connected to the first contact 13, and the second bonding layer can be used to bond the driving substrate 1 and the LED epitaxial layer on the substrate.

[0153] The LED epitaxial layer, the first bonding layer, the first electrode 216, and the second bonding layer can be formed by a deposition method.

[0154] The bonding layer 215 is formed by metal-bonding the first bonding layer and the second bonding layer, thereby bonding the LED epitaxial layer to the driving substrate 1.

[0155] The substrate is peeled off from the LED epitaxial layer. The peeling method of the substrate includes but is not limited to laser peeling, dry etching, wet etching, mechanical polishing, etc.

[0156] A thinning operation is performed on the LED epitaxial layer. The thinning operation includes dry etching, wet etching, or mechanical polishing, etc.

[0157] According to the MESA pattern designed by a patterning mask, the bonded LED epitaxial layer is etched, and then the bonding layer 215 is etched to form a plurality of intermediates. Each intermediate includes a first doped semiconductor layer 211, a light-emitting layer 212, and a second doped semiconductor layer 213. The etching is performed by a dry or wet method.

[0158] The passivation layer 214 is deposited on the side surface of the intermediate, and the second electrode 217 is deposited on the passivation layer 214, so that the second electrode 217 connects the second doped semiconductor layer 213 and the second contact 12. Thereby, a plurality of LED units 21 are formed.

[0159] Figures 5 to 8 shows a schematic structural diagram of forming the first fence structure 22. In some embodiments of the present application, referring to Figures 5 to 8 , forming the first fence structure 22 includes: forming a first light-blocking matrix material layer 221a on a plurality of LED units 21; etching the first light-blocking matrix material layer 221a to form a plurality of first grid holes surrounding a plurality of LED mesa surfaces, obtaining a first light-blocking matrix 221; forming a first reflective material layer 222a on the plurality of LED mesa surfaces and the first light-blocking matrix 221; etching the first reflective material layer 222a to form a first reflective layer 222 at least on the sidewalls of the first grid holes.

[0160] The first light-blocking matrix material layer 221a can be formed on the plurality of LED units 21. As Figure 5 shown.

[0161] Etch the first light-blocking matrix material layer 221a to form a first light-blocking matrix 221 having a plurality of first grid holes. The plurality of first grid holes respectively surround a plurality of LED mesa surfaces, and a depression is formed between the LED mesa surfaces and the corresponding first grid holes. As Figure 6 shown.

[0162] Form a first reflective material layer 222a on the plurality of LED mesa surfaces and the first light-blocking matrix 221. The first reflective material layer 222a can be deposited by means such as atomic layer deposition (ALD), chemical vapor deposition (CVD), evaporation, sputtering, etc. As Figure 7 shown.

[0163] Etch the first reflective material layer 222a on the plurality of LED mesa surfaces to form a first reflective layer 222 on the sidewalls of the first grid holes and the top surface of the first light-blocking matrix 221. The etching can be dry etching, including but not limited to ion beam etching (IBE), inductively coupled plasma etching (ICP), etc. By using dry etching, the entire surface can be etched after the deposition of the first reflective material layer 222a, so that the first reflective material on the plurality of LED mesa surfaces is etched clean. At the same time, during the etching process, there will be a plasma re-deposition effect on the first reflective material layer 222a, resulting in the thickening of the first reflective material layer 222a on the sidewalls of the first grid holes, enhancing the reflective effect and strengthening the stability of the first fence structure 22. As Figure 8 shown.

[0164] In some embodiments of the present application, before forming the first fence structure 22, the preparation method may further include: forming an etching stop layer; wherein, the etching stop layer covers the plurality of LED units 21 to prevent damage to the plurality of LED mesa surfaces when etching the first fence structure 22.

[0165] In some embodiments of the present application, before etching the first reflective material layer 222a on multiple LED platforms, the preparation method may further include: forming a sacrificial coating on the first reflective material layer 222a; removing the sacrificial coating exposed on the first grid holes; etching the first reflective material layer 222a on multiple LED platforms; and removing the remaining sacrificial coating.

[0166] Figures 9 to 13 A schematic structural diagram of forming the optical layer 23 is shown. In some embodiments of the present application, referring to Figures 9 to 13 , forming the optical layer 23 includes: planarizing the first fence structure 22 with a filler 233; forming a transparent transition material layer 231a on the planarized first fence structure 22; etching the position of the transparent transition material layer 231a corresponding to each first grid hole to form vias, obtaining a transparent transition layer 231; removing the filler 233 at the corresponding first grid hole of each LED platform and the transparent transition layer 231 through the vias; and forming a transmissive reflective layer 232 on the transparent transition layer 231.

[0167] Each first grid hole of the first fence structure 22 is filled with the filler 233. The filling height is the top of the grid network of the first fence structure 22. The filler 233 can be selected from organic resin materials. As Figure 9 shown.

[0168] A transparent transition material layer 231a is formed on the planarized first fence structure 22. The material of the transparent transition material layer 231a can be a transparent inorganic oxide material, such as silicon dioxide, aluminum oxide, etc. At the same time, the thickness of the transparent transition material layer 231a can be as thin as possible. The transparent transition material layer 231a can be deposited by methods such as atomic layer deposition (ALD), chemical vapor deposition (CVD), evaporation, sputtering, etc. As Figure 10 shown.

[0169] Etching the position of the transparent transition material layer 231a corresponding to each first grid hole to form vias, obtaining a transparent transition layer 231. The diameter of the vias is not greater than 0.5 μm. The method of forming the vias can be, but is not limited to, high-precision lithography, photoresist reflow, graphic step transfer, etc. As Figure 11 shown.

[0170] Removing the filler 233 at the corresponding first grid hole of each LED platform and the transparent transition layer 231 through the vias. The method of removing the filler 233 can be: using O2 plasma to apply glue without direction, isotropically pumping dry the filler 233 to form a cavity region. As Figure 12 shown.

[0171] A transmissive and reflective layer 232 is formed on the transparent transition layer 231. The transmissive and reflective layer 232 can be deposited by means such as reactive ion deposition, evaporation, sputtering, etc. The transmissive and reflective layer 232 can be a distributed Bragg reflector. As Figure 13 shown.

[0172] In some embodiments of the present application, the step of etching through holes corresponding to the positions of each first grid hole in the transparent transition material layer 231a may include: depositing a mask on the transparent transition material layer 231a, spin-coating photoresist; exposing and developing using a lithography machine to obtain a mask pattern; dry-etching the mask to form openings corresponding to each first grid hole; reactive ion etching the transparent transition material layer 231a to form through holes; removing the photoresist and the mask.

[0173] Figures 14 to 16 shows a schematic structural diagram of forming a light conversion structure. In some embodiments of the present application, referring to Figures 14 to 16 , the preparation method further includes: forming a light conversion structure 3. Forming the light conversion structure 3 includes: forming a second fence structure 31 on the optical layer 23; wherein, the second fence structure 31 has a plurality of second grid holes, and the plurality of second grid holes correspond to the plurality of first grid holes one by one; forming a plurality of light conversion units 32 in the plurality of second grid holes.

[0174] The second fence structure 31 can be formed on the optical layer 23. As Figure 14 shown.

[0175] In some embodiments of the present application, forming the second fence structure 31 on the optical layer 23 includes: forming a second light-blocking matrix material layer on the optical layer 23; etching the second light-blocking matrix material layer to form a plurality of second grid holes corresponding to the first grid holes one by one to obtain a second light-blocking matrix 311; forming a second reflective material layer on the optical layer 23 and the second light-blocking matrix 311; etching the second reflective material layer to form a second reflective layer 312 at least on the side walls of the second grid holes.

[0176] It should be particularly noted that the method of forming the second light-blocking matrix material layer is similar to the method of forming the first light-blocking matrix material layer 221a, the method of forming the second light-blocking matrix is similar to the method of forming the first light-blocking matrix 221, the method of forming the second reflective material layer is similar to the method of forming the first reflective material layer 222a, and the method of forming the second reflective layer 312 is similar to the method of forming the first reflective layer 222. Please refer to the method of forming the first fence structure 22 proposed above, which will not be elaborated here.

[0177] Forming a plurality of light conversion units 32 in the plurality of second grid holes. As Figure 15 and Figure 16 shown.

[0178] In some embodiments of the present application, a plurality of light conversion units 32 are formed in a plurality of second grid holes, including: filling a light conversion material in the plurality of second grid holes; wherein, the light conversion material at least includes: a first light conversion material, a second light conversion material, and a transparent material; filling the first light conversion material in some of the second grid holes to form a first light conversion unit 321 to convert the light passing through the optical layer 23 into light of a first color; filling the second light conversion material in some of the second grid holes to form a second light conversion unit 322 to convert the light passing through the optical layer 23 into light of a second color; filling the transparent material in some of the second grid holes to form a transparent unit 324 to transmit the light passing through the optical layer 23.

[0179] In the case where the LED unit 21 emits blue light, as Figure 15 shown, the first light conversion material can be formed in the second grid holes. The first light conversion material can be filled by spin coating and drying.

[0180] Irradiate the area where the first light conversion unit 321 needs to be formed with light. The area where the first light conversion unit 321 needs to be formed can be exposed by masking other areas.

[0181] Remove the mask layer and develop the first light conversion material with a developer. Since only the area of the first light conversion unit 321 has been light-cured, the rest will be removed under the action of the developer, thereby forming the first light conversion unit 321 in some of the second grid holes and converting the blue light emitted by the corresponding LED unit into red light.

[0182] A second light conversion unit 322 can also be formed in other second grid holes of the second fence structure 31 to convert the blue light emitted by the corresponding LED unit into green light; a transparent unit 324 can be formed in other second grid holes of the second fence structure 31 to directly transmit the blue light emitted by the corresponding LED unit. That is, different light conversion units 32 are formed in different second grid holes. Thus, a full-color Micro LED microdisplay chip is realized.

[0183] In some embodiments of the present application, a plurality of light conversion units 32 are formed in a plurality of second grid holes, including: filling a light conversion material in the plurality of second grid holes; wherein, the light conversion material at least includes: a first light conversion material, a second light conversion material, and a third light conversion material; filling the first light conversion material in a part of the second grid holes to form a first light conversion unit 321 for converting the light passing through the optical layer 23 into a first color light; filling the second light conversion material in a part of the second grid holes to form a second light conversion unit 322 for converting the light passing through the optical layer 23 into a second color light; filling the third light conversion material in a part of the second grid holes to form a third light conversion unit 323 for converting the light passing through the optical layer 23 into a third color light.

[0184] In the case where the LED unit 21 does not emit blue light, as Figure 16 shown, the first light conversion material can be formed in the second grid holes. The first light conversion material can be filled by spin coating and drying methods.

[0185] Irradiate the area where the first light conversion unit 321 needs to be formed with light. The area where the first light conversion unit 321 needs to be formed can be exposed by covering other areas with a mask layer.

[0186] Remove the mask layer, and develop the first light conversion material with a developer. Since only the area of the first light conversion unit 321 has been cured by light irradiation, the rest will be removed under the action of the developer, thereby forming the first light conversion unit 321 in part of the second grid holes, and converting the blue light emitted by the corresponding LED unit into red light.

[0187] A second light conversion unit 322 can also be formed in other second grid holes of the second fence structure 31 to convert the blue light emitted by the corresponding LED unit into green light; a third light conversion unit 323 can be formed in other second grid holes of the second fence structure 31 to convert the blue light emitted by the corresponding LED unit into blue light. That is, different light conversion units 32 are formed in different second grid holes. Thus, a full-color Micro LED microdisplay chip is realized.

[0188] In the preparation method proposed by the present application, after flattening treatment with a filler, a transparent transition material layer is deposited, vias are etched at positions corresponding to each first grid hole in the transparent transition material layer, and after draining the filler with the vias, a transmission and reflection layer is deposited to seal the cavity area.

[0189] In the preparation method proposed by the present application, the vias only need to correspond to the positions of the first grid holes, so the requirement for the position accuracy of etching the vias is not high.

[0190] For the preparation method proposed in this application, after draining the filler through the vias, only by depositing the transmissive and reflective layer can the cavity area be sealed, which neither requires precise alignment nor complex filling.

[0191] Compared with the prior art, such as Chinese patent documents CN119050126A or CN119050236A, the preparation method proposed in this application can seal the cavity area through a simple process, and then limit the heat generated by the LED unit from being transferred to the light conversion structure through the cavity area. This not only extends the service life of the microdisplay chip, but also reduces the manufacturing cost and improves the product yield, making it suitable for large-scale production.

[0192] As described above, this is only the specific implementation manner of this application. Under the above teaching of this application, those skilled in the art can make other improvements or deformations based on the above embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of this application, and the protection scope of this application should be subject to the protection scope of the claims.

[0193] In addition, those skilled in the art can understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of this application and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

Claims

1. A Micro LED micro display chip, characterized in that: The micro display chip comprises: a driving substrate and a light emitting structure arranged on the driving substrate; The light emitting structure comprises: a plurality of LED units, a first fence structure and an optical layer; The plurality of LED units are arranged on the driving substrate at intervals, and each of the LED units can be driven individually by the driving substrate, and the plurality of LED units have a plurality of LED tables corresponding to each other; The first fence structure has a plurality of first grid holes, the plurality of first grid holes respectively surround the plurality of LED table tops, and the first fence structure is higher than the plurality of LED units; The optical layer is disposed on the first fence structure, and the LED table and the optical layer form a cavity area at the corresponding first grid holes; The optical layer comprises: a transparent transition layer disposed on the first fence structure and a transmissive reflective layer disposed on the transparent transition layer; The optical layer is used to transmit light from the plurality of LED units.

2. The Micro LED micro display chip according to claim 1, characterized in that: The first fence structure comprises: a first light-blocking substrate and a first light-reflecting layer arranged on the surface of the first light-blocking substrate; The first light-shielding substrate has a plurality of the first grid holes; The first light reflecting layer is at least arranged on the side wall of the first grid hole.

3. The Micro LED micro display chip according to claim 1, characterized in that: The transparent transition layer has a via hole at a position corresponding to each of the first grid holes.

4. The Micro LED micro display chip according to claim 1, characterized in that: The transmissive reflective layer is a distributed Bragg reflective layer.

5. The Micro LED micro display chip according to claim 1, characterized in that: The material of the transparent transition layer is transparent inorganic oxide.

6. The Micro LED micro display chip according to claim 3, characterized in that: The diameter of the via hole is less than 0.5 μm.

7. The Micro LED micro display chip according to claim 1, characterized in that: The micro display chip further includes: a light conversion structure disposed on the optical layer; The light conversion structure comprises: a second fence structure and a plurality of light conversion units; The second fence structure has a plurality of second grid holes, and the plurality of second grid holes correspond one to one with the plurality of first grid holes; The plurality of light conversion units are respectively disposed in the plurality of second grid holes.

8. The Micro LED micro display chip according to claim 7, characterized in that: The second fence structure comprises: a second light-blocking substrate and a second light-reflecting layer arranged on the surface of the second light-blocking substrate; The second light-shielding substrate has a plurality of the second grid holes; The second light reflecting layer is at least arranged on the side wall of the second grid hole.

9. The Micro LED micro display chip according to claim 7, characterized in that: The plurality of light conversion units at least include: a first light conversion unit and a second light conversion unit; The first light conversion unit converts the light passing through the optical layer into a first color light; The second light conversion unit converts the light passing through the optical layer into second color light.

10. The Micro LED micro display chip according to claim 9, characterized in that: The plurality of light conversion units further include: a transparent unit; The transparent unit transmits light passing through the optical layer.

11. The Micro LED micro display chip according to claim 9, characterized in that: The plurality of light conversion units further include: a third light conversion unit; The third light conversion unit converts the light passing through the optical layer into a third color light.

12. A method for preparing a Micro LED micro display chip, characterized in that: The preparation method comprises the following steps: Providing a driving substrate, and forming a light emitting structure on the driving substrate; Wherein, forming a light emitting structure on the driving substrate comprises: Forming a plurality of LED units; wherein the plurality of LED units are arranged on the driving substrate at intervals from each other, and each of the LED units can be driven individually by the driving substrate, and the plurality of LED units have a plurality of LED tables corresponding to each other; Forming a first fence structure; wherein the first fence structure has a plurality of first grid holes, the plurality of first grid holes respectively surround the plurality of LED table tops, and the first fence structure is higher than the plurality of LED units; forming an optical layer; wherein the optical layer is formed on the first fence structure, and the LED table and the optical layer form a cavity area at the corresponding first grid holes; Wherein, the forming of the optical layer comprises: Using filler to flatten the first fence structure; forming a transparent transition material layer on the planarized first fence structure; Etching the transparent transition material layer at a position corresponding to each of the first grid holes to form a via hole, thereby obtaining a transparent transition layer; Removing the filler from each of the LED tables and the transparent transition layer at the corresponding first grid holes through the via holes; A transmissive reflective layer is formed on the transparent transition layer.

13. The method for preparing a Micro LED micro display chip according to claim 12, characterized in that: The forming of the first fence structure comprises: forming a first light-blocking matrix material layer on the plurality of LED units; Etching the first light-blocking matrix material layer to form a plurality of the first grid holes surrounding the plurality of LED tabletops to obtain the first light-blocking matrix; forming a first light-reflecting material layer on the plurality of LED tables and the first light-blocking substrate; The first light reflecting material layer is etched to form a first light reflecting layer at least on the sidewalls of the first grid holes.

14. The method for preparing a Micro LED micro display chip according to claim 12, characterized in that: The preparation method further comprises: forming a light conversion structure; The light conversion structure is formed, comprising: forming a second fence structure on the optical layer; wherein the second fence structure has a plurality of second grid holes, and the plurality of second grid holes correspond one to one to the plurality of first grid holes; A plurality of light conversion units are formed in the plurality of second grid holes.

15. The method for preparing a Micro LED micro display chip according to claim 14, characterized in that: The forming of a second fence structure on the optical layer comprises: forming a second light-blocking matrix material layer on the optical layer; Etching the second light-shielding matrix material layer to form a plurality of second grid holes corresponding to the first grid holes one by one, thereby obtaining the second light-shielding matrix; forming a second light reflecting material layer on the optical layer and the second light blocking substrate; The second light reflecting material layer is etched to form a second light reflecting layer at least on the sidewalls of the second grid holes.

16. The method for preparing a Micro LED micro display chip according to claim 14, characterized in that: The forming of a plurality of light conversion units in a plurality of the second grid holes comprises: Filling a plurality of the second grid holes with a light conversion material; wherein the light conversion material at least includes: a first light conversion material and a second light conversion material; Filling the first light conversion material in part of the second grid holes to form a first light conversion unit to convert the light passing through the optical layer into a first color light; The second light conversion material is filled in a portion of the second grid holes to form a second light conversion unit to convert the light passing through the optical layer into a second color light.

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