Transfer device and method for preparing display panel

Abstract

The present invention relates to the field of display panel technology, and discloses a transfer device and a method for manufacturing a display panel. In this method, a laser is irradiated on the side of the growth substrate facing away from a first temporary substrate, i.e., a laser lift-off process is performed to transfer the epitaxial layer to the first temporary substrate. In other words, the epitaxial layer of the present invention is first transferred to the first temporary substrate before forming a micro-luminescent device. In this way, during the laser lift-off process, the epitaxial layer can block the laser and prevent the laser from irradiating the bonding layer on the first temporary substrate, thereby reducing the degree to which the bonding layer is affected by the laser, thereby improving the yield of the laser lift-off process.

Description

Technical Field

[0001] The present invention relates to the technical field of display panels, and in particular to a transfer device and a method for preparing a display panel. Background Art

[0002] Micro-LED display technology, with its advantages of high brightness, fast response time, low power consumption, and long life, is becoming a research hotspot for the next generation of display technology. Micro-LED display technology involves the batch transfer of LED chips, efficiently and with high yield, transferring hundreds of thousands of LED chips to a driver backplane.

[0003] Micro-LED batch transfer processes include laser lift-off (LLO). However, in current LLO processes, the temporary bonding layer on the temporary substrate used to transfer the LED chips is easily affected by the laser, resulting in a low yield rate for the current LLO process. Summary of the Invention

[0004] In view of this, the main technical problem to be solved by the present invention is to provide a transfer device and a method for preparing a display panel, which can improve the yield of the laser lift-off process.

[0005] To solve the above technical problems, the present invention adopts a technical solution: providing a method for manufacturing a display panel. The method includes: forming an epitaxial layer on a growth substrate; bonding the epitaxial layer to a bonding layer on a first temporary substrate; irradiating the growth substrate with a laser on a side facing away from the first temporary substrate to transfer the epitaxial layer to the first temporary substrate; patterning the epitaxial layer to form at least two micro-light-emitting devices; and transferring the micro-light-emitting devices on the first temporary substrate to a driver backplane.

[0006] In one embodiment of the present invention, the step of patterning the epitaxial layer to form at least two micro-light-emitting devices includes: patterning the epitaxial layer using an etching gas to form at least two epitaxial units; and forming an electrode on each epitaxial unit to form a micro-light-emitting device.

[0007] In one embodiment of the present invention, the etching depth of the etching gas stops at the surface of the bonding layer facing the epitaxial layer.

[0008] In one embodiment of the present invention, the bonding layer is made of polyimide.

[0009] In one embodiment of the present invention, the step of patterning the epitaxial layer to form at least two micro-light-emitting devices includes: patterning the epitaxial layer to form at least two epitaxial units; forming an electrode on a side of each epitaxial unit facing away from the first temporary substrate, wherein the epitaxial unit and the electrode thereon constitute the micro-light-emitting device.

[0010] In one embodiment of the present invention, the step of transferring the micro light-emitting devices on the first temporary substrate to the driving backplane includes: directly transferring the micro light-emitting devices on the first temporary substrate to the driving backplane.

[0011] In one embodiment of the present invention, the step of directly transferring the micro-light-emitting devices on the first temporary substrate to the driving backplane includes: providing at least two first temporary substrates, wherein the micro-light-emitting devices on different first temporary substrates have different luminous colors; and directly transferring the micro-light-emitting devices on each first temporary substrate to the driving backplane.

[0012] In one embodiment of the present invention, the step of patterning the epitaxial layer to form at least two micro-light-emitting devices includes: patterning the epitaxial layer to form at least two epitaxial units; forming an electrode on a side of each epitaxial unit facing away from the first temporary substrate, wherein the epitaxial unit and the electrode thereon constitute a micro-light-emitting device; forming a light-blocking structure on a side of each epitaxial unit facing away from the first temporary substrate, wherein the light-blocking structure covers the outer surface of the epitaxial unit except the area occupied by the electrode.

[0013] In one embodiment of the present invention, the step of forming a light-blocking structure on the side of each epitaxial unit facing away from the first temporary substrate includes: forming a light-blocking material layer on the side of the first temporary substrate facing the epitaxial unit, wherein the light-blocking material layer covers each epitaxial unit and the electrodes thereon, and also covers the bonding layer between adjacent epitaxial units; removing the light-blocking material layer covering the electrodes, and retaining the light-blocking material layer covering the outer surface of the epitaxial unit to form a light-blocking structure.

[0014] In one embodiment of the present invention, the light-shielding material layer is made of photoresist with light-blocking properties, has a thickness of 0.1 μm to 10 μm, and is in a grid shape.

[0015] In one embodiment of the present invention, the step of removing the light-shielding material layer covering the electrode further comprises: removing the light-shielding material layer covering the bonding layer between adjacent epitaxial units.

[0016] In one embodiment of the present invention, before transferring the micro-light-emitting devices on the first temporary substrate to the driving backplane, the steps include: forming a plurality of retaining structures on the driving backplane, wherein retaining grooves are formed between adjacent retaining structures; and transferring the micro-light-emitting devices into the retaining grooves to restrict the position of the micro-light-emitting devices on the driving backplane. In one embodiment of the present invention, the retaining structures are adhesive and / or elastic.

[0017] In one embodiment of the present invention, the limiting structure is made of photoresist, has a thickness of 0.5 μm to 50 μm, and is in a grid shape.

[0018] To solve the above technical problems, the present invention adopts another technical solution: providing a transfer device. The transfer device includes a first temporary substrate; a bonding layer stacked on the first temporary substrate; and an epitaxial layer disposed on a side of the bonding layer facing away from the first temporary substrate. The epitaxial layer is a single-layer structure and is used to form a micro-luminescent device.

[0019] The beneficial effects of the present invention are as follows: Different from the prior art, the present invention provides a transfer device and a method for preparing a display panel. In this preparation method, a laser is irradiated on the side of the growth substrate facing away from the first temporary substrate, that is, a laser lift-off process is performed to transfer the epitaxial layer to the first temporary substrate. In other words, the epitaxial layer of the present invention is first transferred to the first temporary substrate before forming the micro-light-emitting device. In this way, the epitaxial layer can block the laser during the laser lift-off process, preventing the laser from irradiating the bonding layer on the first temporary substrate, thereby reducing the degree to which the bonding layer is affected by the laser, thereby improving the yield of the laser lift-off process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the description, serve to explain the principles of the present invention. In addition, these drawings and the description are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by reference to specific embodiments.

[0021] Figure 1 1 is a schematic flow chart of an embodiment of a method for manufacturing a display panel according to the present invention;

[0022] Figure 2 is a schematic flow chart of another embodiment of a method for manufacturing a display panel of the present invention;

[0023] Figures 3a-3g yes Figure 2 Schematic diagram of the structure of each step in the preparation method shown;

[0024] Figure 4 1 is a schematic structural diagram of an embodiment of a transfer device of the present invention;

[0025] Figure 5 It is a schematic structural diagram of another embodiment of the transfer device of the present invention. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention. The following embodiments and features in the embodiments can be combined with each other unless there is a conflict.

[0027] See also Figure 1 , Figure 1 1 is a flow chart of an embodiment of a method for manufacturing a display panel according to the present invention.

[0028] S101: forming an epitaxial layer on a growth substrate.

[0029] In this embodiment, some structures related to the fabrication of the micro-light-emitting device are formed on the growth substrate, while the remaining structures related to the fabrication of the micro-light-emitting device are formed in other process steps. Specifically, an epitaxial layer is formed on the growth substrate, and the epitaxial layer is used to subsequently form the micro-light-emitting device.

[0030] S102: Bonding the epitaxial layer to the bonding layer on the first temporary substrate.

[0031] In this embodiment, before the epitaxial layer is formed into a micro-light-emitting device, the entire epitaxial layer is transferred to a first temporary substrate. A bonding layer is formed on the first temporary substrate, which is used to temporarily bond the epitaxial layer on the growth substrate. Specifically, to separate the epitaxial layer from the growth substrate, the growth substrate and the first temporary substrate need to be joined so that the epitaxial layer bonds to the bonding layer on the first temporary substrate, facilitating the subsequent laser lift-off process.

[0032] S103: irradiating a laser on a side of the growth substrate facing away from the first temporary substrate to transfer the epitaxial layer to the first temporary substrate.

[0033] In this embodiment, after the epitaxial layer is bonded to the bonding layer on the first temporary substrate, a laser lift-off process can be performed. Specifically, a laser is irradiated on the side of the growth substrate facing away from the first temporary substrate to transfer the epitaxial layer to the first temporary substrate.

[0034] The entire epitaxial layer can shield the laser, thereby preventing the laser from irradiating the bonding layer on the first temporary substrate, reducing the degree to which the bonding layer is affected by the laser, and thereby improving the yield of the laser lift-off process.

[0035] S104: performing patterning on the epitaxial layer to form at least two micro light-emitting devices.

[0036] In this embodiment, after the epitaxial layer is transferred to the first temporary substrate, the epitaxial layer is patterned to form at least two micro-light-emitting devices. Specifically, the epitaxial layer is patterned to separate the epitaxial layer into at least two epitaxial units. Electrodes are then formed on the side of each epitaxial unit facing away from the first temporary substrate, thereby forming at least two micro-light-emitting devices.

[0037] S105: transferring the micro light-emitting devices on the first temporary substrate to a driving backplane.

[0038] In this embodiment, after forming the micro-light-emitting devices on the first temporary substrate, the micro-light-emitting devices on the first temporary substrate are transferred to the driving backplane. The driving backplane is integrated with a driving circuit, and the micro-light-emitting devices are electrically connected to the driving circuit, which is used to drive the micro-light-emitting devices to emit light for display.

[0039] From the above, it can be seen that in this embodiment, the epitaxial layer is first transferred to the first temporary substrate before forming the micro-light-emitting device. In this way, the epitaxial layer can block the laser during the laser lift-off process to prevent the laser from irradiating the bonding layer on the first temporary substrate, thereby reducing the degree to which the bonding layer is affected by the laser, thereby improving the yield of the laser lift-off process.

[0040] See also Figure 2 and Figures 3a-3g , Figure 2 FIG. 1 is a flow chart of another embodiment of a method for manufacturing a display panel according to the present invention. Figures 3a-3g yes Figure 2 Schematic diagram of the structures of each step in the preparation method shown.

[0041] S201: forming an epitaxial layer on a growth substrate.

[0042] In this embodiment, if Figure 3a As shown, an epitaxial layer 24 is formed on the growth substrate 10 , and the epitaxial layer 24 is used to subsequently form the micro light-emitting device 20 .

[0043] S202: Bonding the epitaxial layer to the bonding layer on the first temporary substrate.

[0044] In this embodiment, if Figure 3b As shown, before the epitaxial layer 24 is formed into the micro-light-emitting device 20, the entire epitaxial layer 24 is first transferred to a first temporary substrate 50. A bonding layer 51 is formed on the first temporary substrate 50, which is used to temporarily bond the epitaxial layer 24 on the growth substrate 10. Specifically, to separate the epitaxial layer 24 from the growth substrate 10, the growth substrate 10 and the first temporary substrate 50 need to be joined so that the epitaxial layer 24 is bonded to the bonding layer 51 on the first temporary substrate 50, facilitating the subsequent laser lift-off process.

[0045] Optionally, the bonding layer 51 may be made of a photosensitive adhesive, which exhibits reduced adhesion when exposed to laser light of a specific wavelength. Specifically, the bonding layer 51 may be made of a triazene polymer, polyimide, or the like. The thickness of the bonding layer 51 may range from 1 μm to 1 mm. Furthermore, the bonding layer 51 is entirely applied to the first temporary substrate 50.

[0046] S203: irradiating a laser on a side of the growth substrate facing away from the first temporary substrate to transfer the epitaxial layer to the first temporary substrate.

[0047] In this embodiment, if Figure 3b and Figure 3c As shown, after the epitaxial layer 24 is bonded to the bonding layer 51 on the first temporary substrate 50 , the laser lift-off process can be performed. Specifically, a laser is irradiated on the side of the growth substrate 10 facing away from the first temporary substrate 50 to transfer the epitaxial layer 24 to the first temporary substrate 50 .

[0048] The entire epitaxial layer 24 can shield the laser, thereby preventing the laser from irradiating the bonding layer 51 on the first temporary substrate 50 , reducing the degree to which the bonding layer 51 is affected by the laser, and thereby improving the yield of the laser lift-off process.

[0049] S204: performing patterning on the epitaxial layer to form at least two epitaxial units.

[0050] In this embodiment, if Figure 3d As shown, after the epitaxial layer 24 is transferred to the first temporary substrate 50, the epitaxial layer 24 is patterned to form at least two micro-light-emitting devices 20. Specifically, the epitaxial layer 24 is first patterned to form at least two epitaxial units 21, that is, the epitaxial layer 24 is separated into at least two epitaxial units 21.

[0051] Furthermore, the epitaxial layer 24 is patterned using an etching gas to form the at least two epitaxial units 21. Furthermore, the etching depth of the etching gas is cut off at the surface of the bonding layer 51 facing the epitaxial layer 24. In other words, by properly selecting the etching gas used to etch the epitaxial layer 24, the etching gas will not corrode the bonding layer 51, which is conducive to ensuring the stability of the bonding layer 51. For example, a mixed gas of boron chloride and chlorine is selected.

[0052] Optionally, since the epitaxial layer 24 generates a large amount of heat during the patterning process, the bonding layer 51 is preferably made of a high-temperature resistant material, such as polyimide, which is beneficial to ensure the stability of the bonding layer 51 .

[0053] S205: forming an electrode on a side of each epitaxial unit facing away from the first temporary substrate.

[0054] In this embodiment, if Figure 3d As shown, after forming at least two epitaxial units 21, an electrode 22 is formed on a side of each epitaxial unit 21 facing away from the first temporary substrate 50. Each epitaxial unit 21 and the electrode 22 thereon constitute a micro light-emitting device 20.

[0055] S206: forming a light-blocking structure on a side of each epitaxial unit facing away from the first temporary substrate.

[0056] In this embodiment, if Figure 3e As shown, a light-blocking structure 71 is formed on the side of each epitaxial unit 21 facing away from the first temporary substrate 50. The light-blocking structure 71 covers the outer surface of the epitaxial unit 21 except for the area occupied by the electrode 22. As a result, after the micro-light-emitting devices 20 of this embodiment are transferred to the driving backplane 40, the light-blocking structure 71 can prevent crosstalk between the light output from adjacent micro-light-emitting devices 20, thereby reducing the difficulty of packaging the micro-light-emitting devices 20.

[0057] Furthermore, the specific process of forming the light-blocking structure 71 on the side of each epitaxial unit 21 facing away from the first temporary substrate 50 can be: forming a light-shielding material layer on the side of the first temporary substrate 50 facing the epitaxial unit 21, wherein the light-shielding material layer covers each epitaxial unit 21 and the electrode 22 thereon, and the light-shielding material layer also covers the bonding layer 51 between adjacent epitaxial units 21. Thereafter, the light-shielding material layer covering the electrode 22 is removed, and the light-shielding material layer covering the outer surface of the epitaxial unit 21 is retained to form the light-blocking structure 71. Removing the light-shielding material layer covering the electrode 22 can facilitate the subsequent electrical connection of the electrode 22 to the drive circuit.

[0058] Optionally, the light-shielding material layer may be made of a photoresist with light-blocking properties. The thickness of the light-shielding material layer may be 0.1 μm to 10 μm to ensure that the light-shielding material layer has sufficient light-blocking properties. In addition, the light-shielding material layer is in a grid shape.

[0059] Furthermore, in the process of removing the shading material layer covering the electrode 22, the shading material layer covering the bonding layer 51 between adjacent epitaxial units 21 is also removed, which can facilitate the separation of the epitaxial unit 21 from the bonding layer 51, and further facilitate the transfer of the micro-light-emitting device 20 to the driving backplane 40.

[0060] S207: providing at least two first temporary substrates, and directly transferring the micro-light-emitting devices on each of the first temporary substrates to a driving backplane.

[0061] In this embodiment, if Figure 3f and Figure 3gAs shown, since the micro-light-emitting device 20 is fabricated on the bonding layer 51 of the first temporary substrate 50, the electrode 22 of the micro-light-emitting device 20 is already away from the first temporary substrate 50. This allows the micro-light-emitting device 20 to be directly transferred to the driving backplane 40 without first transferring the micro-light-emitting device 20 to a temporary substrate other than the first temporary substrate 50 and then to the driving backplane 40. This reduces the number of transfers of the micro-light-emitting device 20, which helps improve the transfer efficiency and yield of the micro-light-emitting device 20.

[0062] Furthermore, at least two first temporary substrates 50 are provided, wherein the micro-light-emitting devices 20 on different first temporary substrates 50 emit different colors, and the micro-light-emitting devices 20 on the same first temporary substrate 50 emit the same color. Furthermore, the micro-light-emitting devices 20 on each first temporary substrate 50 can be obtained using the above-described method and steps. To achieve the integration of micro-light-emitting devices 20 with multiple luminous colors on the driver backplane 40, this embodiment selectively transfers the micro-light-emitting devices 20 on each first temporary substrate 50 directly to the driver backplane 40.

[0063] A plurality of retaining structures 80 are formed on the driver backplane 40. Retaining grooves 81 are formed between adjacent retaining structures 80. The retaining grooves 81 expose the solder 41 on the driver backplane 40 for electrically connecting the micro-light-emitting devices 20. The electrodes 22 of the micro-light-emitting devices 20 are electrically connected to the driver circuit board through the solder 41.

[0064] Optionally, the solder 41 may be made of ACF (Anisotropic Conductive Film) or metal solder, and the solder 41 may be made of indium, tin, indium-tin alloy or other metal solder.

[0065] In this embodiment, the micro-light emitting device 20 is transferred to the limiting groove 81. In this embodiment, the limiting groove 81 limits the position of the micro-light emitting device 20 on the driving back plate 40, thereby reducing the risk of thermal mismatch, sliding, crystal breakage, and other problems occurring during the electrical connection between the micro-light emitting device 20 and the driving back plate 40.

[0066] Optionally, the limiting structure 80 can be made of a photoresist, such as PDMS (Polydimethylsiloxane). The limiting structure 80 has a thickness of 0.5 μm to 50 μm. By properly setting the thickness of the limiting structure 80, that is, properly setting the size of the limiting groove 81, the limiting groove 81 can reliably limit the micro-light-emitting device 20 and ensure that the electrode 22 of the micro-light-emitting device 20 can contact the solder 41. In addition, the limiting structure 80 has a grid shape.

[0067] A layer of photoresist is spin-coated on the driver backplane 40 and then subjected to processes such as baking, exposure, and development to form the retaining structure 80 and the retaining groove 81. Furthermore, the retaining structure 80 may be viscous and / or elastic, meaning that the retaining structure 80 exhibits at least one of these properties. The viscous retaining structure 80 can temporarily secure the micro-light-emitting device 20 after it has been transferred to the retaining groove 81, further reducing the risk of the micro-light-emitting device 20 slipping. Furthermore, the elastic retaining structure 80 can act as a buffer for the micro-light-emitting device 20 during its transfer to the retaining groove 81, reducing the impact force on the micro-light-emitting device 20 and facilitating the transfer yield of the micro-light-emitting device 20.

[0068] As can be seen from the above, in this embodiment, the epitaxial layer 24 is first transferred to the first temporary substrate 50 before forming the micro-light-emitting device 20. In this way, the epitaxial layer 24 can block the laser during the laser lift-off process to prevent the laser from irradiating the bonding layer 51 on the first temporary substrate 50, thereby reducing the degree to which the bonding layer 51 is affected by the laser, thereby improving the yield of the laser lift-off process.

[0069] See also Figure 4 , Figure 4 It is a structural schematic diagram of an embodiment of a transfer device of the present invention.

[0070] In one embodiment, the transfer device includes a first temporary substrate 50. The transfer device also includes a bonding layer 51. The bonding layer 51 is stacked on the first temporary substrate 50. The bonding layer 51 is used to temporarily bond the micro-light-emitting device on the growth substrate, allowing the micro-light-emitting device to be transferred to the bonding layer 51 after the micro-light-emitting device is separated from the growth substrate in a subsequent laser lift-off process.

[0071] The transfer device further includes an epitaxial layer 24. The epitaxial layer 24 is disposed on the side of the bonding layer 51 facing away from the first temporary substrate 50. The epitaxial layer 24 is a whole-layer structure, that is, the epitaxial layer 24 is entirely laid on the bonding layer 51, and the epitaxial layer 24 is used to form a micro-light-emitting device.

[0072] In other words, the epitaxial layer 24 is first transferred to the first temporary substrate 50 before forming the micro-light emitting device. The epitaxial layer 24 is separated from the growth substrate by a laser lift-off process, and then the epitaxial layer 24 is formed on the bonding layer 51 to form the micro-light emitting device.

[0073] In the above manner, since the epitaxial layer 24 on the bonding layer 51 is a whole layer structure, the epitaxial layer 24 can block the laser during the laser stripping process, preventing the laser from irradiating the bonding layer 51 on the first temporary substrate 50, thereby reducing the degree to which the bonding layer 51 is affected by the laser, thereby improving the yield of the laser stripping process.

[0074] Optionally, since the epitaxial layer 24 generates a large amount of heat during the process of forming the micro-light-emitting device, the bonding layer 51 is preferably made of a high-temperature resistant material, such as polyimide, which is beneficial to ensure the stability of the bonding layer 51 .

[0075] Further, please also refer to Figure 5 The transfer device further includes a growth substrate 10 , which is located on a side of the epitaxial layer 24 facing away from the bonding layer 51 .

[0076] Furthermore, in the present invention, unless otherwise expressly specified or limited, terms such as "connected," "connected," and "stacked" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two elements or interaction between two elements. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a display panel, characterized in that: The preparation method comprises: forming an epitaxial layer on a growth substrate; bonding the epitaxial layer to the bonding layer on the first temporary substrate; irradiating a laser on a side of the growth substrate facing away from the first temporary substrate to transfer the epitaxial layer to the first temporary substrate; performing patterning on the epitaxial layer to form at least two micro light-emitting devices; transferring the micro light-emitting device on the first temporary substrate to a driving backplane; The step of patterning the epitaxial layer to form at least two micro-light-emitting devices includes: performing patterning on the epitaxial layer to form at least two epitaxial units; forming an electrode on a side of each epitaxial unit facing away from the first temporary substrate, wherein the epitaxial unit and the electrode thereon constitute the micro light-emitting device; forming a light-shielding material layer on a side of the first temporary substrate facing the epitaxial units, wherein the light-shielding material layer covers each epitaxial unit and the electrodes thereon, and also covers the bonding layer between adjacent epitaxial units; removing the light-shielding material layer covering the electrode and the bonding layer between adjacent epitaxial units, and retaining the light-shielding material layer covering the outer surface of the epitaxial unit to form a light-blocking structure; Wherein, before the step of transferring the micro-light-emitting device on the first temporary substrate to the driving backplane, the method further comprises: A plurality of limiting structures are formed on the driving back plate, wherein limiting grooves are formed between adjacent limiting structures; The micro-light emitting device is transferred to the limiting groove to limit the position of the micro-light emitting device on the driving backplane, and the limiting structure has viscosity and elasticity.

2. The preparation method according to claim 1, characterized in that The step of patterning the epitaxial layer to form at least two epitaxial units includes: The epitaxial layer is patterned using an etching gas to form at least two epitaxial units.

3. The preparation method according to claim 2, characterized in that The etching depth of the etching gas stops at the surface of the bonding layer facing the epitaxial layer.

4. The preparation method according to claim 1 or 2, characterized in that The bonding layer is made of polyimide.

5. The preparation method according to claim 1, characterized in that The step of transferring the micro-light emitting device on the first temporary substrate to a driving backplane comprises: The micro light-emitting device on the first temporary substrate is directly transferred to the driving backplane.

6. The preparation method according to claim 5, characterized in that The step of directly transferring the micro-light-emitting device on the first temporary substrate to the driving backplane includes: providing at least two first temporary substrates, wherein the micro-light-emitting devices on different first temporary substrates emit different colors of light; The micro light-emitting devices on each first temporary substrate are directly transferred to the driving backplane.

7. The preparation method according to claim 1, characterized in that The light-shielding material layer is made of photoresist with light-blocking properties, has a thickness of 0.1 μm to 10 μm, and is in a grid shape.

8. The preparation method according to claim 1, characterized in that The material of the limiting structure is photoresist, the thickness of the limiting structure is 0.5 μm to 50 μm, and the limiting structure is in a grid shape.

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