MicroLED chip with multi-layer micro lens structure and preparation method thereof

Abstract

The invention relates to the technical field of display chips, and discloses a MicroLED chip with a multi-layer microlens structure and a preparation method thereof.The MicroLED chip with the multi-layer microlens structure comprises a driving substrate, a light-emitting layer and the microlens structure, the microlens structure is arranged at a light outlet in the top of an epitaxial layer and comprises at least two layers of lenses, and the light-emitting layer is arranged on the driving substrate. According to the invention, the multi-layer micro-lens structure is arranged at the light outlet of the light-emitting unit, and the refractive index matching of multiple materials is utilized, so that the internal total reflection is reduced, the light efficiency is improved, the brightness is improved, the light-emitting angle is reduced, the light energy waste is reduced, and the power consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of display chips, and specifically relates to a MicroLED chip with a multi-layer microlens structure and a preparation method thereof. Background Art

[0002] Micro LED stands for Micro Light Emitting Diode, and in Chinese it's called micro-light-emitting diode, also known as μLED. It generally refers to a technology that uses LED light-emitting units ranging in size from 1 to 60 μm to form a display array. The underlying MicroLED technology uses a standard CMOS integrated circuit manufacturing process to create an LED display driver circuit. An MOCVD machine is then used to create an LED array on the integrated circuit, thus creating a micro-display, or what is known as a scaled-down version of an LED display. MicroLED display panels typically include multiple LED pixels (i.e., light-emitting units). Currently, Micro LEDs are manufactured by etching away continuous functional epitaxial layers to create multiple, completely isolated functional pixels. The light emitted by MicroLED pixels is relatively scattered and has low light utilization efficiency. Microlens structures are typically added to improve light utilization and collimation.

[0003] For example, Japanese patent application number JP2007273975A discloses a light-emitting device, which specifically includes a semiconductor layer 1 including a P-type semiconductor layer 11, a light-emitting layer 12, and an N-type semiconductor layer 13. The top surface of the N-type semiconductor layer 13 is provided with an array of microlens structures, and the microlens structure can be a convex lens that focuses light. For another example, Chinese patent application number CN115472730B discloses a Micro LED micro-display chip, which includes: a driver panel; a plurality of LED units arranged on the driver panel, the plurality of LED units having a one-to-one correspondence of a plurality of LED mesas, each of the LED units being capable of being driven individually by the driver panel; a fence structure having a plurality of grid holes, the plurality of grid holes being respectively arranged around the plurality of LED mesas, with recessed areas formed between the LED mesas and the corresponding grid holes; and a plurality of microlenses, each having a light-emitting curved surface, the microlenses being filled in the corresponding recessed areas and configured to focus and / or collimate the light emitted by the LED units.

[0004] Currently, Micro LED display panels with microlens structures all have a certain focusing effect, but they are all single-layer lens structures and are limited to changes in shape and material, and the focusing effect on light is poor. Therefore, there is an urgent need to develop a new type of microlens structure to further improve the collimation of Micro LED pixel light sources, thereby improving light utilization and increasing the brightness of Micro LED. Summary of the Invention

[0005] In order to address the deficiencies mentioned in the above background technology, the purpose of the present invention is to provide a MicroLED chip with a multi-layer microlens structure and a preparation method thereof. By setting a multi-layer microlens structure at the light outlet of the light-emitting unit and utilizing multi-material refractive index matching, internal total reflection is reduced, light efficiency is improved, and brightness is increased. At the same time, the light output angle is reduced, light energy waste is reduced, and power consumption is reduced.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A MicroLED chip with a multi-layer microlens structure includes a driving substrate having metal contacts connected to internal circuits;

[0008] The light-emitting layer includes a leveling layer, in which light-emitting units are arranged in a rectangular array. The light-emitting units include an epitaxial layer, an ITO layer is provided at the bottom of the epitaxial layer, an insulating layer is provided on the sidewalls of the epitaxial layer and the bottom of the ITO layer, a reflective layer is provided between the epitaxial layers, the reflective layer is deposited on the outer wall of the insulating layer, an electrode transition layer is provided at the bottom of the ITO layer, the electrode transition layer penetrates the insulating layer and the leveling layer, the ITO layer is connected to the metal contacts of the driving substrate through the electrode transition layer, an N electrode layer is provided on the top of the epitaxial layer, and the N electrode layer has an opening corresponding to the light outlet of the epitaxial layer;

[0009] The microlens structure is arranged at the light outlet on the top of the epitaxial layer. The microlens structure includes at least two layers of lenses. The refractive index of the lens material in the microlens structure decreases from the inside to the outside.

[0010] In some embodiments, the driving substrate is a silicon-based CMOS backplane or a TFT field effect transistor display substrate.

[0011] In some embodiments, the leveling layer is organic black matrix photoresist, color filter photoresist, polyimide, barrier glue, OC glue, SU8 photoresist, benzocyclobutene, Al, Cu, Ag, SiO2, Al2O3, ZrO2, TiO2, Si3N4 or HfO2.

[0012] In some embodiments, the insulating layer is SiO2, Al2O3, or Si3N4.

[0013] In some embodiments, the reflective layer is made of a highly reflective dielectric material.

[0014] In some embodiments, the N-electrode layer material is one or more of metals selected from the group consisting of Cr, Ti, Pt, Au, Al, Cu, Ge, and Ni.

[0015] In some embodiments, the lens surface is one of a sphere, an ellipsoid or a parabola, and the lens material is one of H-K9, Al2O3, MgF2, TiO2, SiN, and SiO2.

[0016] The present invention also provides a method for preparing a MicroLED chip having a multi-layer microlens structure, comprising the following steps:

[0017] S1, sputtering an ITO film on the surface of the epitaxial layer of the epitaxial wafer, and then etching the ITO film by photolithography-etching to pattern it;

[0018] S2, etching the epitaxial layer by dry or wet etching to form independent pixels;

[0019] S3, filling the insulating layer material and patterning;

[0020] S4. forming a reflective layer on the surface of the insulating layer by evaporation or deposition;

[0021] S5, filling the leveling layer and etching the electrode connection layer holes;

[0022] S6, filling bonding metal, CMP removes excess metal, and forms an electrode transition layer;

[0023] S7, bonding the epitaxial wafer to the driving substrate, and removing the epitaxial wafer substrate;

[0024] S8, forming an N-electrode layer on the surface of the reflective layer by photolithography, evaporation or lift-off, and completing the patterning of the N-electrode layer;

[0025] S9. Fill the lens materials in sequence and pattern them to form a multi-layer lens structure.

[0026] Beneficial effects of the present invention:

[0027] The present invention sets a multi-layer microlens structure at the light outlet of the light-emitting unit and utilizes multi-material refractive index matching to reduce internal total reflection, improve light efficiency, and enhance brightness. At the same time, it reduces the light output angle, with a narrow angle of less than 20°, reducing light energy waste, reducing invalid scattering due to the directionality of light, and reducing power consumption at the same brightness. For full-color products, reducing the light output angle can suppress the problem of light crosstalk between pixels and improve the color deviation problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] Figure 1 2 is a schematic structural diagram of a MicroLED chip with a multi-layer microlens structure in Example 1 of the present invention;

[0030] Figure 2 Schematic diagram of the process flow of step S1 of the present invention;

[0031] Figure 3 Schematic diagram of the process flow of step S2 of the present invention;

[0032] Figure 4 Schematic diagram of the process flow of step S3 of the present invention;

[0033] Figure 5 Schematic diagram of the process flow of step S4 of the present invention;

[0034] Figure 6 Schematic diagram of the process flow of step S5 of the present invention;

[0035] Figure 7 Schematic diagram of the process flow of step S6 of the present invention;

[0036] Figure 8 Schematic diagram of the process flow of step S7 of the present invention;

[0037] Figure 9 Schematic diagram of the process flow of step S8 of the present invention;

[0038] Figure 10 Schematic diagram of the process flow of step S9 of the present invention;

[0039] Figure 11 : This is a test curve of the divergence angle light intensity of the MicroLED chip with a multi-layer microlens structure in Example 1, Example 2, Example 5, Example 6 and Comparative Example 1 of the present invention;

[0040] Figure 12 3 and 4 are test curves of the divergence angle light intensity of the MicroLED chip with a multi-layer microlens structure in Examples 3, 4, 7, 8 and Comparative Example 2 of the present invention.

[0041] In the figure: 1-substrate, 2-epitaxial layer, 3-ITO layer, 4-insulating layer, 5-reflective layer, 6-leveling layer, 7-electrode transition layer, 8-driving substrate, 9-metal contact, 10-N electrode layer, 11-first lens, 12-second lens, 13-third lens. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] Example 1

[0044] A MicroLED chip with a multi-layer microlens structure, such as Figure 1 As shown, it includes a driving substrate 8, and the driving substrate 8 has metal contacts 9 connected to the internal circuit;

[0045] The light-emitting layer includes a leveling layer 6, in which light-emitting units are arranged in a rectangular array. The light-emitting units include an epitaxial layer 2, an ITO layer 3 is provided at the bottom of the epitaxial layer 2, an insulating layer 4 is provided on the sidewalls of the epitaxial layer 2 and the bottom of the ITO layer 3, a reflective layer 5 is provided between the epitaxial layers 2, and the reflective layer 5 is deposited on the outer wall of the insulating layer 4. An electrode transition layer 7 is also provided at the bottom of the ITO layer 3, and the electrode transition layer 7 passes through the insulating layer 4 and the leveling layer 6. The ITO layer 3 is connected to the metal contact 9 of the driving substrate 8 through the electrode transition layer 7. An N electrode layer is provided on the top of the epitaxial layer, and the N electrode layer has an opening corresponding to the light outlet of the epitaxial layer;

[0046] The microlens structure is arranged at the light outlet at the top of the epitaxial layer 2. The microlens structure includes a first lens 11, a second lens 12, and a third lens 13 arranged in sequence from the inside to the outside. The first lens 11, the second lens 12, and the third lens 13 are all spherical. The specific parameters of the first lens 11, the second lens 12, and the third lens 13 are shown in Table 1 below.

[0047] Table 1 Lens parameters of the microlens structure in Example 1

[0048]

[0049]

[0050] In this embodiment, the driving substrate is a silicon-based CMOS backplane, the leveling layer is polyimide, the insulating layer is SiO2, the reflective layer is Al, and the N-electrode layer material is metal Cu.

[0051] Figures 2 to 10 The schematic diagrams of the structure of the MicroLED chip with a multi-layer microlens structure at different stages of the manufacturing process are illustrated. The manufacturing method specifically includes the following steps:

[0052] S1, sputtering an ITO film on the surface of the epitaxial layer of the epitaxial wafer, and then etching the ITO film by photolithography-etching to pattern it;

[0053] S2, etching the epitaxial layer by dry or wet etching to form independent pixels;

[0054] S3, filling the insulating layer material and patterning;

[0055] S4. forming a reflective layer on the surface of the insulating layer by evaporation or deposition;

[0056] S5, filling the leveling layer and etching the electrode connection layer holes;

[0057] S6, filling bonding metal, CMP removes excess metal, and forms an electrode transition layer;

[0058] S7, bonding the epitaxial wafer to the driving substrate, and removing the epitaxial wafer substrate;

[0059] S8, forming an N-electrode layer on the surface of the reflective layer by photolithography, evaporation or lift-off, and completing the patterning of the N-electrode layer;

[0060] S9, filling a first layer of lens material and patterning it, then filling a second layer of lens material and patterning it, and repeating this process multiple times to form a multi-layer lens structure.

[0061] Example 2

[0062] A MicroLED chip with a multi-layer microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and light-emitting layer are the same as those in Example 1. The microlens structure is disposed at the light exit at the top of the epitaxial layer. The microlens structure includes a first lens, a second lens, and a third lens, arranged sequentially from the inside out. The first lens, the second lens, and the third lens are all spherical. Specific parameters of the first lens, the second lens, and the third lens are shown in Table 2.

[0063] Table 2 Lens parameters of the microlens structure in Example 2

[0064] First lens Second lens The third lens Material <![CDATA[TiO2]]> SiN <![CDATA[SiO2]]> Surface coefficient 0 0 0 curvature 0.67 0.625 0.588 Radius (μm) 1.5 1.6 1.8 Thickness (μm) 1.6 2 3.5

[0065] In this embodiment, the driving substrate is a silicon-based CMOS backplane, the leveling layer is SU8 photoresist, the insulating layer is Al2O3, the reflective layer is Ag, and the N-electrode layer material is Al.

[0066] The preparation method of the MicroLED chip with a multi-layer microlens structure is the same as that in Example 1.

[0067] Example 3

[0068] A MicroLED chip with a multi-layer microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and light-emitting layer are the same as those in Example 1. The microlens structure is disposed at the light exit at the top of the epitaxial layer. The microlens structure includes a first lens, a second lens, and a third lens, arranged sequentially from the inside out. The first lens, the second lens, and the third lens are all parabolic. Specific parameters of the first lens, the second lens, and the third lens are shown in Table 3.

[0069] Table 3 Lens parameters of the microlens structure in Example 3

[0070] First lens Second lens The third lens Material H-K9 <![CDATA[Al2O3]]> <![CDATA[MgF2 <!-- 4 -->]]> Surface coefficient -1 -1 -1 curvature Aspheric Aspheric Aspheric Radius (μm) 1.5 1.6 1.7 Thickness (μm) 2.1 2.3 2.8

[0071] In this embodiment, the driving substrate is a silicon-based CMOS backplane, the leveling layer is an organic black matrix photoresist, the insulating layer is Si3N4, the reflective layer is Al, and the N-electrode layer material is metal Au.

[0072] The preparation method of the MicroLED chip with a multi-layer microlens structure is the same as that in Example 1.

[0073] Example 4

[0074] A MicroLED chip with a multi-layer microlens structure includes a driver substrate, a light-emitting layer, and a microlens structure. The driver substrate and light-emitting layer are the same as those in Example 1. The microlens structure is disposed at the light exit at the top of the epitaxial layer. The microlens structure includes a first lens, a second lens, and a third lens, disposed sequentially from the inside out. The first lens, the second lens, and the third lens are all parabolic. Specific parameters of the first lens, the second lens, and the third lens are shown in Table 4.

[0075] Table 4 Lens parameters of the microlens structure in Example 4

[0076] First lens Second lens The third lens Material H-K9 <![CDATA[Al2O3]]> <![CDATA[MgF2]]> Quadric surface coefficient -1 -1 -1 curvature Aspheric Aspheric Aspheric Radius (μm) 1.5 1.6 1.7 Thickness (μm) 2 2.3 3

[0077] In this embodiment, the driving substrate is a silicon-based CMOS backplane, the leveling layer is a color filter photoresist, the insulating layer is SiO2, the reflective layer is Ag, and the N-electrode layer material is metal Pt.

[0078] The preparation method of the MicroLED chip with a multi-layer microlens structure is the same as that in Example 1.

[0079] Example 5

[0080] A MicroLED chip with a multi-layer microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and light-emitting layer are the same as those in Example 1. The microlens structure is disposed at the light exit at the top of the epitaxial layer. The microlens structure includes a first lens and a second lens disposed sequentially from the inside out. Both the first lens and the second lens are spherical. Specific parameters of the first lens and the second lens are shown in Table 5.

[0081] Table 5 Lens parameters of the microlens structure in Example 5

[0082] First lens Second lens Material <![CDATA[TiO2]]> <![CDATA[SiO2]]> Surface coefficient 0 0 curvature 0.71 0.588 Radius (μm) 1.4 1.7 Thickness (μm) 1.6 2.5

[0083] In this embodiment, the driving substrate is a TFT field effect tube display substrate, the leveling layer is polyimide, the insulating layer is Si3N4, the reflective layer is Ag, and the N-electrode layer material is metal Pt.

[0084] The preparation method of the MicroLED chip with a multi-layer microlens structure is the same as that in Example 1.

[0085] Example 6

[0086] A MicroLED chip with a multi-layer microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and light-emitting layer are the same as those in Example 1. The microlens structure is arranged at the light outlet at the top of the epitaxial layer. The microlens structure includes a first lens and a second lens arranged sequentially from the inside out. Both the first lens and the second lens are spherical. Specific parameters of the first lens and the second lens are shown in Table 6 below.

[0087] Table 6 Lens parameters of the microlens structure in Example 6

[0088] First lens Second lens Material <![CDATA[TiO2]]> <![CDATA[MgF2]]> Surface coefficient 0 0 curvature 0.71 0.588 Radius (μm) 1.4 1.7 Thickness (μm) 1.6 3.5

[0089] In this embodiment, the driving substrate is a TFT field effect tube display substrate, the leveling layer is an organic black matrix photoresist, the insulating layer is Al2O3, the reflective layer is high Al, and the N electrode layer material is metal Ti.

[0090] The preparation method of the MicroLED chip with a multi-layer microlens structure is the same as that in Example 1.

[0091] Example 7

[0092] A MicroLED chip with a multi-layer microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and light-emitting layer are the same as those in Example 1. The microlens structure is arranged at the light outlet at the top of the epitaxial layer. The microlens structure includes a first lens and a second lens arranged sequentially from the inside out. Both the first lens and the second lens are parabolic. Specific parameters of the first lens and the second lens are shown in Table 7.

[0093] Table 7 Lens parameters of the microlens structure in Example 7

[0094]

[0095]

[0096] In this embodiment, the driving substrate is a TFT field effect tube display substrate, the leveling layer is OC glue, the insulating layer is SiO2, the reflective layer is Ag, and the N-electrode layer material is metal Au.

[0097] The preparation method of the MicroLED chip with a multi-layer microlens structure is the same as that in Example 1.

[0098] Example 8

[0099] A MicroLED chip with a multi-layer microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and light-emitting layer are the same as those in Example 1. The microlens structure is arranged at the light outlet at the top of the epitaxial layer. The microlens structure includes a first lens and a second lens arranged sequentially from the inside out. Both the first lens and the second lens are parabolic. Specific parameters of the first lens and the second lens are shown in Table 8.

[0100] Table 8 Lens parameters of the microlens structure in Example 8

[0101] First lens Second lens Material H-K9 <![CDATA[MgF2]]> Surface coefficient -1 -1 curvature Aspheric Aspheric Radius (μm) 1.4 1.7 Thickness (μm) 2.3 3

[0102] In this embodiment, the driving substrate is a TFT field effect tube display substrate, the leveling layer is made of benzocyclobutene, the insulating layer is made of SiO2, the reflective layer is made of Al, and the N-electrode layer is made of metal Cu.

[0103] The preparation method of the MicroLED chip with a multi-layer microlens structure is the same as that in Example 1.

[0104] Comparative Example 1

[0105] A MicroLED chip with a microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and the light-emitting layer are the same as those in Example 1. The microlens structure is arranged at the light outlet at the top of the epitaxial layer. The microlens structure is a layer of spherical lens with a radius of 1.8 μm and a thickness of 2.5 μm, and the material is TiO2.

[0106] Comparative Example 2

[0107] A MicroLED chip with a microlens structure includes a driving substrate, a light-emitting layer, and a microlens structure. The driving substrate and the light-emitting layer are the same as those in Example 1. The microlens structure is arranged at the light outlet at the top of the epitaxial layer. The microlens structure is a parabolic lens with a surface coefficient of -1, a curvature of 1.2, a thickness of 2.8 μm, and a material of TiO2.

[0108] Performance testing

[0109] The divergence angle light intensity test of the MicroLED chips with microlens structures in Examples 1 to 8 and Comparative Examples 1 to 2 was carried out, and the results were as follows: Figure 11 and Figure 12 As shown, the horizontal axis in the figure is the divergence angle (°), and the vertical axis is the light intensity (cd) at the corresponding divergence angle. Therefore, the more the curve in the figure converges towards the vertical axis, the smaller the divergence angle width of the microlens structure is, and the better the light focusing effect of the microlens structure is. The higher the height of the curve in the figure, the higher the brightness of the MicroLED.

[0110] from Figure 11 and Figure 12 It can be seen that the microlens structures in Examples 1, 2, 5, and 6 have a greater light focusing effect than Comparative Example 1, and the microlens structures in Examples 3, 4, 7, and 8 have a greater light focusing effect than Comparative Example 2. This shows that the multi-layer microlens structure (three-layer and two-layer) provided by the present invention has a significantly improved light collimation effect compared to the single-layer microlens structure, has excellent light collimation effect, reduces ineffective scattering, reduces light energy waste, and improves light efficiency and brightness. It can also be seen that the spherical microlens structure has a greater light focusing effect than the aspherical structure.

[0111] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0112] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A MicroLED chip with a multi-layer microlens structure, characterized in that: The drive substrate includes a driving substrate having metal contacts connected to an internal circuit; The light-emitting layer includes a leveling layer, in which light-emitting units are arranged in a rectangular array. The light-emitting units include an epitaxial layer, an ITO layer is provided at the bottom of the epitaxial layer, an insulating layer is provided on the sidewalls of the epitaxial layer and the bottom of the ITO layer, a reflective layer is provided between the epitaxial layers, the reflective layer is deposited on the outer wall of the insulating layer, an electrode transition layer is provided at the bottom of the ITO layer, the electrode transition layer penetrates the insulating layer and the leveling layer, the ITO layer is connected to the metal contacts of the driving substrate through the electrode transition layer, an N electrode layer is provided on the top of the epitaxial layer, and the N electrode layer has an opening corresponding to the light outlet of the epitaxial layer; The microlens structure is arranged at the light outlet on the top of the epitaxial layer. The microlens structure includes at least two layers of lenses. The refractive index of the lens material in the microlens structure decreases from the inside to the outside.

2. The MicroLED chip with a multi-layer microlens structure according to claim 1, wherein: The driving substrate is a silicon-based CMOS backplane or a TFT field effect tube display substrate.

3. The MicroLED chip with a multi-layer microlens structure according to claim 1, wherein: The leveling layer is one of organic black matrix photoresist, color filter photoresist, polyimide, wall glue, OC glue, SU8 photoresist, benzocyclobutene, Al, Cu, Ag, SiO2, Al2O3, ZrO2, TiO2, Si3N4 or HfO2.

4. The MicroLED chip with a multi-layer microlens structure according to claim 1, wherein: The insulating layer is one of SiO2, Al2O3 or Si3N4.

5. The MicroLED chip with a multi-layer microlens structure according to claim 1, wherein: The reflective layer is made of a highly reflective dielectric material.

6. The MicroLED chip with a multi-layer microlens structure according to claim 1, wherein: The N electrode layer material is one or more of metals selected from Cr, Ti, Pt, Au, Al, Cu, Ge and Ni.

7. The MicroLED chip with a multi-layer microlens structure according to claim 1, wherein: The lens surface is one of a spherical surface, an ellipsoidal surface or a parabolic surface, and the lens material is one of H-K9, Al2O3, MgF2, TiO2, SiN, and SiO2.

8. The method for preparing a MicroLED chip having a multi-layer microlens structure according to any one of claims 1 to 7, wherein: The following steps are involved: S1, sputtering an ITO film on the surface of the epitaxial layer of the epitaxial wafer, and then etching the ITO film by photolithography-etching to pattern it; S2, etching the epitaxial layer by dry or wet etching to form independent pixels; S3, filling the insulating layer material and patterning; S4. forming a reflective layer on the surface of the insulating layer by evaporation or deposition; S5, filling the leveling layer and etching the electrode connection layer holes; S6, filling bonding metal, CMP removes excess metal, and forms an electrode transition layer; S7, bonding the epitaxial wafer to the driving substrate, and removing the epitaxial wafer substrate; S8, forming an N-electrode layer on the surface of the reflective layer by photolithography, evaporation or lift-off, and completing the patterning of the N-electrode layer; S9, filling a first layer of lens material and patterning it, then filling a second layer of lens material and patterning it, and repeating this process multiple times to form a multi-layer lens structure.

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