Micro light-emitting diode display chip and manufacturing method therefor, and display apparatus

Abstract

Disclosed in the present application are a micro light-emitting diode (LED) display chip and a manufacturing method therefor, and a display apparatus. The display chip comprises a drive substrate, a wavelength conversion layer and a plurality of display screens, wherein the drive substrate comprises a plurality of contacts; the plurality of display screens are arranged on the drive substrate at intervals, and are located on the same plane; each display screen comprises a plurality of LED units arranged in an array, the LED units being used for emitting light of a first color and being separately driven by means of corresponding contacts; and the wavelength conversion layer is arranged on the side of the display screens that is away from the drive substrate. In the display chip of the present application, a plurality of display screens, which are located on the same plane, are arranged on a drive substrate, and the same basic primary color is used for the entire screen; and a quantum dot process can then be used to implement the full-color display of the entire chip. Since the entire surface is of the same basic primary color, the bonding yield of LED units is greatly increased.

Description

Miniature LED display chip and its fabrication method, display device

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411620334.9, filed on November 13, 2024, entitled “Miniature Light Emitting Diode Display Chip and Preparation Method Thereof, Display Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of micro-display technology, specifically relating to a micro light-emitting diode display chip, its fabrication method, and a display device. Background Technology

[0004] To achieve color projection, a three-color combining technique, which uses red, green, and blue light sources to synthesize a color image, was developed. This technique allows three independent light sources to control the color and brightness of each pixel, thus offering advantages such as high resolution and high brightness. Miniature light-emitting diode (LED) display chips not only have the characteristics of small size but also offer advantages such as high brightness, low power consumption, fast response, long lifespan, and high luminous efficiency, making them suitable as light sources for color projection. However, during the combining process, each independent light source requires precise alignment in both time and space to combine them into a seamless color image. However, alignment deviations in the independent light sources can lead to problems such as color misalignment, blurring, or artifacts in the image. Summary of the Invention

[0005] This application provides a micro light-emitting diode (LED) display chip, comprising a driving substrate, a wavelength conversion layer, and multiple display screens. The driving substrate includes multiple contacts, and the multiple display screens are spaced apart on the driving substrate and located on the same plane. Each display screen includes multiple LED units arranged in an array, each LED unit emitting light of a first color, and each LED unit is individually driven through a corresponding contact. The wavelength conversion layer is located on the side of the display screen facing away from the driving substrate. The wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit. The first wavelength conversion unit is correspondingly configured with all the LED units in one display screen to form a first display module, capable of converting the first color light into a second color light. The second wavelength conversion unit is correspondingly configured with all the LED units in another display screen to form a second display module, capable of converting the first color light into a third color light.

[0006] In one specific embodiment of the first aspect of this application, the wavelength conversion layer further includes a third wavelength conversion unit, which is configured in correspondence with all the LED units in another display screen to form a third display module. The third wavelength conversion unit is capable of converting the first color light into the fourth color light.

[0007] In one specific embodiment of the first aspect of this application, the display screen may further include a grid layer located on the side surface of the driving substrate facing the wavelength conversion layer. The grid layer has a plurality of grid holes corresponding to LED units, and the LED units are disposed in the corresponding grid holes. The first wavelength conversion unit, the second wavelength conversion unit, and the third wavelength conversion unit are filled in the grid holes.

[0008] In one specific embodiment of the first aspect of this application, the display screen may further include a bonding layer and a reflective layer. The bonding layer is disposed between the driving substrate and the LED unit, and the LED unit is electrically connected to the bonding layer. The reflective layer at least covers the sidewalls of the grid holes.

[0009] In one specific embodiment of the first aspect of this application, the display screen may further include a passivation layer, an electrode layer, and an etch barrier layer. The passivation layer covers the side of the LED unit, and the electrode layer covers the side of the passivation layer away from the LED unit. The electrode layer is electrically connected to the top surface of both the driving substrate and the LED unit. The passivation layer electrically isolates the electrode layer from the LED unit. The passivation layer also covers the sidewalls of the bonding layer and electrically isolates the electrode layer from the bonding layer. The etch barrier layer is located on the surface of the electrode layer facing the wavelength conversion layer. The electrode layer also has a light-emitting aperture exposing the LED unit, and the etch barrier layer fills the light-emitting aperture and covers the top surface of the LED unit. The etch barrier layer is located between the reflective layer and the electrode layer and electrically isolates the reflective layer from the electrode layer.

[0010] In one specific embodiment of the first aspect of this application, the reflective layer further covers the surface of the grid layer away from the driving substrate, and the surface of the reflective layer away from the grid layer is flush with the surface of the wavelength conversion layer away from the display screen.

[0011] In one specific embodiment of the first aspect of this application, the micro light-emitting diode display chip may further include a first filter layer and a second filter layer. The first filter layer is located on the surface of the first wavelength conversion unit away from the LED unit, and the first filter layer is used to filter other colors of light and allow second colors of light to pass through. The second filter layer is located on the surface of the second wavelength conversion unit away from the LED unit, and the second filter layer is used to filter other colors of light and allow third colors of light to pass through.

[0012] In one specific embodiment of the first aspect of this application, the micro light-emitting diode display chip may further include a third filter layer located on the surface of the third wavelength conversion unit away from the LED unit. The third filter layer is used to filter other colors of light and allow a fourth color of light to pass through.

[0013] In one specific embodiment of the first aspect of this application, the LED unit has a stepped structure, which includes a first doped semiconductor layer, a second doped semiconductor layer, and an active layer located between the two. The stepped structure disconnects and electrically isolates adjacent second doped semiconductor layers, active layers, and first doped semiconductor layers from each other, and the contacts are electrically connected to the corresponding first doped semiconductor layers.

[0014] In one specific embodiment of the first aspect of this application, the size of the LED unit is 0.1 to 10 μm.

[0015] In one specific embodiment of the first aspect of this application, the driving substrate is a silicon-based CMOS driving board or a thin-film field-effect transistor driving board.

[0016] A second aspect of this application provides a method for fabricating a micro light-emitting diode (LED) display chip. The method includes: providing a driving substrate, the driving substrate including multiple contacts; forming an LED epitaxial layer on the driving substrate; dividing the LED epitaxial layer into multiple processing areas; etching the LED epitaxial layer in each processing area to form a display screen, wherein multiple display screens are located on the same plane, each display screen including multiple arrayed LED units, each LED unit emitting light of a first color, and each LED unit being driven individually through corresponding contacts; forming a wavelength conversion layer on the side of the display screen away from the driving substrate, wherein the wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit; in one display screen, a first display module is formed by correspondingly distributing the first wavelength conversion unit on all LED units, the first wavelength conversion unit being capable of converting first-color light into second-color light; in another display screen, a second display module is formed by correspondingly distributing the second wavelength conversion unit on all LED units, the second wavelength conversion unit being capable of converting first-color light into third-color light.

[0017] In one specific embodiment of the second aspect of this application, the wavelength conversion layer further includes a third wavelength conversion unit. The third wavelength conversion unit is correspondingly disposed on all LED units in another display screen to form a third display module. The third wavelength conversion unit is capable of converting the first color light into the fourth color light.

[0018] In one specific embodiment of the second aspect of this application, the step of forming an LED epitaxial layer on a driving substrate includes: providing a substrate having an LED epitaxial layer thereon; forming a bonding layer on the driving substrate and / or the LED epitaxial layer; bonding the driving substrate and the LED epitaxial layer through the bonding layer; and removing the substrate.

[0019] In one specific embodiment of the second aspect of this application, the step of etching the LED epitaxial layer of each processing area to form a display screen includes: etching the LED epitaxial layer to form a plurality of LED units, the LED units being arranged in an array on a bonding layer; forming a grid layer on the side surface of the driving substrate facing the display screen, forming a plurality of grid holes corresponding to the LED units on the grid layer, and the plurality of LED units being disposed in the corresponding grid holes; and forming a reflective layer on the sidewall of the grid holes and on the surface of the grid layer away from the driving substrate.

[0020] In one specific embodiment of the second aspect of this application, the step of etching the LED epitaxial layer in each processing area to form a display screen further includes: forming a passivation layer on the side of the first LED unit and the side of the bonding layer; forming an electrode layer on the side of the passivation layer away from the LED unit, wherein the electrode layer is electrically connected to the corresponding contact and the top surface of the LED unit, and the passivation layer electrically isolates the electrode layer from either the LED unit or the bonding layer; forming a light-emitting hole at the position of the electrode layer corresponding to the top surface of the LED unit, and forming an etching barrier layer on the surface of the electrode layer away from the driving substrate, wherein the etching barrier layer fills the light-emitting hole and covers the top surface of the electrode layer and the LED unit, the etching barrier layer is located between the reflective layer and the electrode layer, and the etching barrier layer electrically isolates the reflective layer and the electrode layer.

[0021] In one specific embodiment of the second aspect of this application, the step of forming a wavelength conversion layer further includes: filling all grid holes in a grid layer of a display screen with a first wavelength conversion unit; and / or, filling all grid holes in a grid layer of another display screen with a second wavelength conversion unit; and / or, filling all grid holes in a grid layer of another display screen with a third wavelength conversion unit; wherein any display screen emits light of one color.

[0022] In one specific embodiment of the second aspect of this application, after the step of forming the wavelength conversion layer, the method further includes: forming a first filter layer on the surface of the first wavelength conversion unit away from the LED unit, the first filter layer being used to filter other colors of light and allow second colors of light to pass through; forming a second filter layer on the surface of the second wavelength conversion unit away from the LED unit, the second filter layer being used to filter other colors of light and allow third colors of light to pass through; and forming a third filter layer on the surface of the third wavelength conversion unit away from the LED unit, the third filter layer being used to filter other colors of light and allow fourth colors of light to pass through.

[0023] A third aspect of this application provides a display device that includes the micro light-emitting diode display chip described in the first aspect above; or, includes the micro light-emitting diode display chip obtained by the preparation method of the second aspect above.

[0024] In one specific embodiment of the third aspect of this application, the light emission direction of the display screen is a first direction, and the direction in which the multiple display screens are spaced apart is a second direction. The first direction and the second direction intersect, and the display device further includes a light combining module. The light combining module includes a first light combining unit and a second light combining unit located on the same plane and spaced apart along the second direction. The first light combining unit is correspondingly disposed with the first display module in the first direction. The first light combining unit is used to convert second color light from the first direction to the second direction for emission. The second light combining unit is correspondingly disposed with the second display module in the first direction and converts third color light from the first direction to the second direction for emission, and allows the second color light emitted along the second direction to pass through.

[0025] In one specific embodiment of the third aspect of this application, the light combining module further includes a third light combining unit. The third light combining unit is located on the same plane as the first light combining unit and the second light combining unit, and the third light combining unit is disposed along the second direction on the side of the second light combining unit away from the first light combining unit. The third light combining unit and the third display module are correspondingly disposed in the first direction. The third light combining unit is used to convert the fourth color light from the first direction to the second direction for emission, and to allow either the second color light or the third color light emitted along the second direction to pass through.

[0026] In one specific embodiment of the third aspect of this application, the first light combining unit has a first optical film facing the first display module, and the orthographic projection of the first optical film on the driving substrate along the first direction covers the first display module; the second light combining unit has a second optical film facing the second display module, and the orthographic projection of the second optical film on the driving substrate along the first direction covers the second display module; the third light combining unit has a third optical film facing the third display module, and the orthographic projection of the third optical film on the driving substrate along the first direction covers the third display module.

[0027] In one specific embodiment of the third aspect of this application, any one of the first optical film, the second optical film, and the third optical film is tilted relative to the surface of the driving substrate. The tilt angle is adjusted according to the light-emitting surface requirements. The first optical film, the second optical film, and the third optical film are arranged parallel to each other to ensure that the light emitted by different light-emitting modules can overlap on the light-emitting surface.

[0028] In one specific embodiment of the third aspect of this application, the first doped semiconductor layer and the second doped semiconductor layer may include one or more layers based on IIVI materials such as ZnSe or ZnO or IIIV nitride materials such as GaN, AlN, InN, InGaN, GaP, AlInGaP, AlGaAs and alloys thereof.

[0029] In one specific embodiment of the third aspect of this application, the first doped semiconductor layer is a p-type semiconductor layer and the second doped semiconductor layer is an n-type semiconductor layer.

[0030] In one specific embodiment of the third aspect of this application, an active layer is further provided between the first doped semiconductor layer and the second doped semiconductor layer. The active layer can be a multi-quantum well structure, which is used to confine electron and hole carriers to the quantum well region. When electrons and holes recombine, the carriers will emit photons after radiative recombination, thus converting electrical energy into light energy.

[0031] Beneficial Effects: Compared with the prior art, the micro light-emitting diode display chip of this application includes a driving substrate, a wavelength conversion layer, and multiple display screens. The driving substrate includes multiple contacts, and the multiple display screens are spaced apart on the driving substrate and located on the same plane. Each display screen includes multiple LED units arranged in an array. The LED units are used to emit light of a first color, and each LED unit is driven individually through a corresponding contact. The wavelength conversion layer is located on the side of the display screen away from the driving substrate. The wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit. The first wavelength conversion unit is correspondingly configured with all the LED units in one display screen to form a first display module, and the first wavelength conversion unit can convert the first color light into second color light. The second wavelength conversion unit is correspondingly configured with all the LED units in another display screen to form a second display module, and the second wavelength conversion unit can convert the first color light into third color light. In the display chip of this application, multiple displays located on the same plane are set on the driving substrate. The entire screen uses the same basic primary color. Then, the full-color display of the entire chip can be completed by using quantum dot technology. Since the entire surface uses the same basic primary color, only one bonding of semiconductor layers and substrate peeling are required, avoiding the yield reduction caused by multiple bonding of semiconductor layers and substrate peeling.

[0032] This application discloses a method for fabricating a micro light-emitting diode (LED) display chip, comprising: providing a driving substrate, the driving substrate including multiple contacts; forming an LED epitaxial layer on the driving substrate and removing the substrate; dividing the LED epitaxial layer into multiple processing areas, etching the LED epitaxial layer in each processing area to form a display screen, wherein multiple display screens are located on the same plane, the display screen including multiple arrayed LED units, the LED units being used to emit light of a first color, and the LED units being driven individually through corresponding contacts; forming a wavelength conversion layer on the side of the display screen away from the driving substrate, wherein the wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit, wherein a first display module is formed by correspondingly distributing the first wavelength conversion unit on all LED units in one display screen, the first wavelength conversion unit being capable of converting the first color light into second color light, and a second display module is formed by correspondingly distributing the second wavelength conversion unit on all LED units in another display screen, the second wavelength conversion unit being capable of converting the first color light into third color light. The fabrication method of this application can realize the fabrication of multiple displays on the same plane by dividing multiple processing areas on the driving substrate. The highly integrated LED unit can improve the compactness and space utilization of the chip, and the display module design is completed by combining wavelength conversion layers, realizing the chip's multi-color display and improving the color display capability of the display chip.

[0033] This application also provides a display device, which includes a micro light-emitting diode display chip and a light-combining module. The light emission direction of the display screen is a first direction, and the direction in which multiple display screens are spaced apart is a second direction. The first direction and the second direction intersect. The light-combining module includes a first light-combining unit and a second light-combining unit located on the same plane and spaced apart along the second direction. The first light-combining unit is correspondingly disposed with a display screen in the first direction and is used to convert second-color light from the first direction to the second direction for emission. The second light-combining unit is correspondingly disposed with another display screen in the second direction and is used to convert third-color light from the first direction to the second direction for emission, and to allow the second-color light emitted along the second direction to pass through. The display device of this application arranges display modules that emit different colors of light on the same driving substrate, so that the light emitted by the display modules is already aligned on the surface along the second direction. The light combining of multiple colors of light can be completed by adjusting the angle and front-back distance of the first light combining unit and the second light combining unit. Compared with the light combining structure of multiple independent display chips through prisms, the alignment difficulty of this application is greatly improved, and the structure and process of the light combining module are simpler, the production efficiency is significantly improved, and it has a wide range of application scenarios. Attached Figure Description

[0034] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0035] Figure 1 shows a partial cross-sectional structural diagram of the micro light-emitting diode display chip of this application;

[0036] Figure 2 shows a schematic diagram of the driving substrate structure provided in this application;

[0037] Figure 3 shows a cross-sectional view along the AA direction in Figure 2;

[0038] Figure 4 shows a schematic diagram of the substrate and LED epitaxial layer structure provided in this application;

[0039] Figure 5 shows a schematic diagram of the bonding process between the substrate and the driving substrate in an embodiment of this application;

[0040] Figure 6 shows a schematic diagram of a processing area on the LED epitaxial layer in an embodiment of this application;

[0041] Figure 7 shows a top view of the structure in Figure 6;

[0042] Figure 8 shows a schematic diagram of forming LED units in the processing area in an embodiment of this application;

[0043] Figure 9 shows a schematic diagram of the formation of the etching barrier layer, the grid layer and the reflective layer in an embodiment of this application;

[0044] Figure 10 shows a top view of the structure in Figure 1;

[0045] Figure 11 shows a schematic diagram of the structure of the display device provided in an embodiment of this application;

[0046] Figure 12 shows a schematic diagram of the light combining principle of the display device;

[0047] Reference numerals: 10-Driver substrate, 102-Contact, 101-Common contact, 20-Display screen, 201-LED unit, 2011-First doped semiconductor layer, 2012-Second doped semiconductor layer, 2013-Active layer, 202-Gate layer, 2021-Gate aperture, 203-Passivation layer, 204-Electrode layer, 2041-Light emission aperture, 205-Reflective layer, 30-Wavelength conversion layer, 301-First wavelength conversion unit, 302-Second wavelength conversion unit, 303-Third wavelength conversion unit Wavelength conversion unit, 40-bonding layer, 50-etching barrier layer, 60-first filter layer, 70-second filter layer, 80-third filter layer, 90-substrate, 901-LED epitaxial layer, 100-first display module, 200-second display module, 300-third display module, 400-processing area, 2-light combining module, 21-first light combining unit, 22-second light combining unit number, 23-third light combining unit, 211-first optical film, 221-second optical film, 231-third optical film. Detailed Implementation

[0048] In some embodiments, the term driving substrate 10 as used herein refers to the material on which subsequent material layers are added. The driving substrate 10 itself may be patterned. The material added on top of the driving substrate 10 may be patterned or may remain unpatterned. The driving substrate 10 may be, for example, but not limited to, a display substrate including a silicon-based CMOS driving board or a thin-film field-effect transistor driving board, such as a CMOS (Complementary Metal Oxide Semiconductor) backplane or a TFT glass substrate.

[0049] In at least one embodiment of this application, referring to Figures 1 and 10, the micro light-emitting diode display chip may include a driving substrate 10, a plurality of display screens 20, and a wavelength conversion layer 30. The driving substrate 10 includes a plurality of contacts 102, and the plurality of display screens 20 are spaced apart on the driving substrate 10 and located on the same plane. Each display screen 20 includes a plurality of LED units 201 arranged in an array. The LED units 201 are used to emit light of a first color, and each LED unit 201 is driven individually through a corresponding contact 102. A wavelength conversion layer 30 is disposed on the side of the display screen 20 away from the driving substrate 10. The wavelength conversion layer 30 includes a first wavelength conversion unit 301 and a second wavelength conversion unit 302. The first wavelength conversion unit 301 is configured with all the LED units 201 in the display screen 20 to form a first display module 100. The first wavelength conversion unit 301 can convert a first color light into a second color light. The second wavelength conversion unit 302 is configured with all the LED units 201 in the other display screen 20 to form a second display module 200. The second wavelength conversion unit 302 can convert a first color light into a third color light.

[0050] It is understood that in the display chip provided in this embodiment, since multiple displays 20 are located on the same plane on the driving substrate 10, the entire display system is more compact and simplified. When multiple displays 20 are located on the same plane, the connections and wiring between components can be reduced, the possibility of errors and defects in the bonding process can be reduced, and the bonding yield can be improved. At the same time, the array arrangement of the displays 20 also makes the bonding process more regular and consistent, improving the bonding yield. The entire screen uses the same basic primary color, and then the quantum dot process can be used to complete the full-color display of the entire chip. Since the entire surface uses the same basic primary color, the bonding yield of the LED unit 201 is greatly improved. Each LED unit 201 is driven individually through the corresponding contact 102. This independent driving design can reduce mutual interference and influence, and improve the accuracy and stability of bonding.

[0051] In some embodiments, further referring to Figures 1 and 10, the wavelength conversion layer 30 may further include a third wavelength conversion unit 303. The third wavelength conversion unit 303 is configured correspondingly with all the LED units 201 in another display screen 20 to form a third display module 300. The third wavelength conversion unit 300 is capable of converting the first color light into a fourth color light. The wavelength conversion layer 30 is located on the side of the display screen 20 away from the driving substrate 10. Through the configuration of the wavelength conversion layer 30, the first color light emitted by the LED unit 201 can be converted into other color light, which provides a light source basis for the subsequent combination of multiple different color lights.

[0052] In some embodiments, the “~” symbol in the drawings represents multiple repeated structures that have been omitted, where multiple specifically refers to a number of two or more.

[0053] In some embodiments, the display screen 20 further includes a grid layer 202, a passivation layer 203, and an electrode layer 204. The grid layer 202 is located on the side surface of the driving substrate 10 facing the wavelength conversion layer 30. The grid layer 202 has a plurality of grid holes 2021 corresponding to LED units 201, and the LED units 201 are disposed in the corresponding grid holes 2021. The first wavelength conversion unit 301, the second wavelength conversion unit 302, and the third wavelength conversion unit 303 fill the grid holes 2021. The passivation layer 203 covers the side surface of the LED units 201. The electrode layer 204 covers the side of the passivation layer 203 away from the LED units 201. The electrode layer 204 is electrically connected to the top surface of the driving substrate 10 and the LED units 201, respectively. The passivation layer 203 electrically isolates the electrode layer 204 from the LED units 201.

[0054] Understandably, the grid layer 202 is located on the surface of the driving substrate 10 facing the wavelength conversion layer 30 and has multiple grid holes 2021 corresponding to the LED units 201. This effectively blocks light interference from other LED units 201, improving the contrast and clarity of the display screen 20 and enhancing the display effect. The first wavelength conversion unit 301, the second wavelength conversion unit 302, and the third wavelength conversion unit 303 fill the grid holes 2021, bringing the wavelength conversion layer 30 closer to the LED units 201, reducing light transmission loss and scattering, and improving the efficiency and accuracy of wavelength conversion. The electrode layer 204 is electrically connected to the top surface of the driving substrate 10 and the LED units 201, respectively, while the passivation layer 203 electrically isolates the electrode layer 204 from the LED units 201, effectively isolating the electrode layer and the LED units and preventing electrical short circuits and interference. Simultaneously, the application of the passivation layer 203 also improves the stability and reliability of the LED units 201.

[0055] In some embodiments, the material of the grid layer 202 is selected from at least one of organic resin, organic black matrix photoresist, color filter photoresist, and polyimide.

[0056] In some embodiments, the passivation layer 203 is made of either inorganic or organic materials to isolate and protect the LED unit 201. The inorganic materials include any one or a combination of SiO2, Al2O3, ZrO2, TiO2, Si3N4, and HfO2. The organic materials include any one or a combination of black matrix photoresist, color filter photoresist, polyimide, barrier adhesive, overcoat adhesive, near-ultraviolet negative photoresist, and styrene.

[0057] In some embodiments, the electrode layer 204 is made of at least one of indium tin oxide, Cr, Ti, Pt, Au, Al, Cu, Ge, or Ni.

[0058] In some embodiments, referring to FIG1, the display chip further includes a bonding layer 40 and an etch barrier layer 50. The bonding layer 40 is disposed between the driving substrate 10 and the LED unit 201, and the LED unit 201 is electrically connected to the bonding layer 40. The passivation layer 203 also covers the sidewall of the bonding layer 40 and electrically isolates the electrode layer 204 from the bonding layer 40. The etch barrier layer 50 is located on the side surface of the electrode layer 204 facing the wavelength conversion layer 30. The electrode layer 204 also has a light-emitting hole 2041 that exposes the LED unit 201. The etch barrier layer 50 fills the light-emitting hole 2041 and covers the top surface of the LED unit 201.

[0059] In some embodiments, the bonding layer 40 is an adhesive material layer that also serves to conduct electricity by being electrically connected to the LED unit 201. The bonding layer 40 is made of metal or a metal alloy. In some embodiments, the bonding layer 40 may include Au, Ag, Cu, Al, and their alloys, but is not limited thereto.

[0060] In some embodiments, the material of the etching barrier layer 50 is selected from silicon dioxide, silicon nitride, aluminum oxide, etc. The main function of the etching barrier layer 50 is to protect the LED unit 201 from being accidentally etched during the etching process. The etching barrier layer 50 also has a shielding function to prevent the etchant from entering the LED unit 201.

[0061] In some embodiments, referring to FIG1, the display screen 20 further includes a reflective layer 205, which at least covers the sidewalls of the grid aperture 2021. An etch barrier layer 50 is located between the reflective layer 205 and the electrode layer 204, electrically isolating the reflective layer 205 and the electrode layer 204. The reflective layer 205, located on the sidewalls of the grid aperture 2021, can effectively reflect the light emitted by the LED unit 201. Through the reflection of the reflective layer 205, the light can be guided back to the front of the display screen, improving the light utilization efficiency. The reflective layer 205 can also reduce light scattering and loss. By reflecting the light back to the display screen 20, energy loss can be reduced, improving the energy efficiency of the display screen. In addition, the etch barrier layer 50, located between the reflective layer 205 and the electrode layer 204, serves as an electrical isolation layer, preventing electrical short circuits or interference between the electrode layer 204 and the reflective layer 205, thus improving the stability and reliability of the display screen. The reflective layer 205 is made of reflective materials such as Al and Ag.

[0062] In some embodiments, referring to FIG1, the reflective layer 205 also covers the surface of the grid layer 202 away from the driving substrate 10, and the surface of the reflective layer 205 away from the grid layer 202 is flush with the surface of the wavelength conversion layer 30 away from the display screen 20. The reflective layer 205 is located between the grid layer 202 and the wavelength conversion layer 30, and can effectively reflect light emitted from the LED unit 201. By covering the grid layer 202 and being flush with the wavelength conversion layer 30, a flat surface facing away from the driving substrate 10 is formed, and the reflective layer 205 can capture and reflect light to the maximum extent, improving light reflection efficiency. Furthermore, the covering of the reflective layer 205 and its flush arrangement with the wavelength conversion layer 30 prevents it from being blocked or scattered by the grid layer 202 or the wavelength conversion layer 30, thereby maintaining light transmission efficiency and directionality.

[0063] In some embodiments, referring to FIG1, the display chip further includes a first filter layer 60, a second filter layer 70, and a third filter layer 80. The first filter layer 60 is located on the surface of the first wavelength conversion unit 301 away from the LED unit 201, and the first filter layer 60 is used to filter other colors of light and allow second colors of light to pass through; the second filter layer 70 is located on the surface of the second wavelength conversion unit 302 away from the LED unit 201, and the second filter layer 70 is used to filter other colors of light and allow third colors of light to pass through; the third filter layer 80 is located on the surface of the third wavelength conversion unit 303 away from the LED unit 201, and the third filter layer 80 is used to filter other colors of light and allow fourth colors of light to pass through.

[0064] It should be noted that the first color light emitted by the LED unit 201 is converted into second, third, and fourth color light by three different wavelength conversion units. For example, the first and second color light can both be blue light, the third color light can be red light, and the fourth color light can be green light; or, the first color light can be ultraviolet light, the second color light can be red light, the third color light can be green light, and the fourth color light can be blue light. In this way, full-color display of the display chip can be realized.

[0065] In some embodiments, the first filter layer 60, the second filter layer 70, and the third filter layer 80 for the first color light are each made of a filter material. Taking an example where the first color light can be ultraviolet light, the second color light can be red light, the third color light can be green light, and the fourth color light can be blue light, the first filter layer 60 uses a red filter material to allow red light to pass through; the second filter layer 70 uses a green filter material to allow green light to pass through; and the third filter layer 80 uses a blue filter material to allow blue light to pass through. For example, the filter material can be an organic color filter photoresist, a Bragg distributed reflector, etc.

[0066] In some embodiments, the wavelength conversion layer may be made of a color conversion material, which may include wavelength conversion particles such as phosphors or quantum dots.

[0067] In some embodiments, referring to FIG8, the LED unit 201 has a stepped structure, which includes a first doped semiconductor layer 2011, a second doped semiconductor layer 2012, and an active layer 2013 located between them. The stepped structure disconnects and electrically isolates adjacent second doped semiconductor layers 2012, active layers 2013, and first doped semiconductor layers 2011 from each other, and the contact 102 is electrically connected to the corresponding first doped semiconductor layer 2011. It can be understood that the stepped structure can prevent current interference between adjacent LED units 201, thereby improving the independence and stability of the LED unit 201.

[0068] In some embodiments, the LED unit 201 can be trapezoidal in shape. That is, the sidewalls of the LED unit 201 can be inclined, and the angle between the sidewalls and the top surface can be obtuse, thereby improving the light-gathering effect of the LED unit 201. It should be understood that the LED unit 201 can also be columnar, in which case the angle between the sidewalls and the top surface of the LED unit 201 is a right angle.

[0069] In some embodiments, the first doped semiconductor layer 2011 and the second doped semiconductor layer 2012 may include one or more layers based on IIVI materials (such as ZnSe or ZnO) or IIIV nitride materials (such as GaN, AlN, InN, InGaN, GaP, AlInGaP, AlGaAs and alloys thereof).

[0070] In some embodiments, the first doped semiconductor layer 2011 may be p-type GaN. In some embodiments, the first doped semiconductor layer 2011 may be p-type InGaN. In some embodiments, the first doped semiconductor layer 2011 may be p-type AlInGaP.

[0071] In some embodiments, the second doped semiconductor layer 2012 may be n-type GaN. In some embodiments, the second doped semiconductor layer 2012 may be n-type InGaN. In some embodiments, the second doped semiconductor layer 2012 may be n-type AlInGaP.

[0072] In some embodiments, the active layer 2013 is the active region of the LED unit 201. The active layer 2013 is disposed between the first doped semiconductor layer 2011 and the second doped semiconductor layer 2012 and provides light. The active layer 2013 is a layer that recombines holes and electrons provided from the first doped semiconductor layer 2011 and the second doped semiconductor layer 2012 respectively and outputs light of a specific wavelength. The active layer 2013 may have a single quantum well structure or a multiple quantum well (MQW) structure and alternating layers of well layers and barrier layers.

[0073] In some embodiments, the spacing between LED units 201 can be 0.1 to 10 μm, and the size of LED unit 201 can be 0.1 to 10 μm. For example, the spacing between LED units 201 can be any one or any two values ​​of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm; the size of LED unit 201 can be any one or any two values ​​of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm.

[0074] In some embodiments, the LED unit 201 can emit any one of red light, green light, blue light, yellow light, or ultraviolet light.

[0075] In some embodiments, the driving substrate 10 may include semiconductor materials such as silicon, silicon carbide, zinc nitride, germanium, zinc arsenide, and zinc phosphide. The driving substrate 10 may have driving circuitry formed therein, and the driving substrate 10 may be a CMOS backplane or a thin-film transistor driving board.

[0076] In some embodiments, referring to FIG1, the driving substrate 10 may further include a common contact 101, and the second doped semiconductor layer 2012 of the plurality of LED units 201 is connected to the corresponding common contact 102. The common contact 101 may be a cathode metal contact, and the contact 102 may be an anode metal contact. The contact 102 is independently connected to each LED unit 201, applying an anode voltage and providing a separate driving signal, thereby achieving the purpose of individually controlling the light emission of each LED unit 201.

[0077] In some embodiments, a method for fabricating a micro light-emitting diode display chip is provided, comprising the following steps S100 to S800.

[0078] S100, referring to Figures 2 and 3, provides a driving substrate 10, which includes a plurality of contacts 101; the driving substrate 10 is a complementary metal-oxide-semiconductor (CMOS) device, and the CMOS device can form a driving circuit in the driving substrate 10.

[0079] S200, see Figure 4, provides a substrate 90, and forms an LED epitaxial layer 901 on the substrate 90.

[0080] For example, the substrate 90 can be a silicon substrate or a sapphire substrate. The specific process of forming the LED epitaxial layer 901 on the substrate 90 is as follows: an n-type layer, an activation layer, and a p-type layer are deposited on the substrate 90, respectively. These layers can be grown using methods such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy. Precise deposition and thin film thickness control can be achieved by controlling parameters such as temperature, flow rate, and reaction time.

[0081] S300, referring to Figure 5, an LED epitaxial layer 901 is formed on the driving substrate 10, and the substrate 90 is removed. First, a bonding layer 40 is formed on the driving substrate 10 and the LED epitaxial layer 90. Then, the substrate 90 is flipped so that the bonding layer 40 on the substrate 90 is opposite to the bonding layer 40 on the driving substrate 10. Through the fusion of the bonding layer 40, the LED epitaxial layer 901 can be bonded to the driving substrate 10. Then, the substrate 90 is peeled off, so that the driving substrate 10 and the LED epitaxial layer 901 are bonded through the bonding layer 40.

[0082] Lifting methods include, but are not limited to, laser lift-off, dry etching, wet etching, and mechanical polishing. The bonding layer 40 can be prepared by atomic layer deposition (ALD), chemical vapor deposition (CVD), evaporation, sputtering, or other methods. In some embodiments, the flipped LED epitaxial layer 901 also needs to be thinned, including by dry etching, wet etching, or mechanical polishing.

[0083] S400, referring to Figures 6 and 7, the LED epitaxial layer 901 is divided into multiple processing regions 400. The LED epitaxial layer 901 in each processing region 400 is etched to form a display screen 20. Multiple display screens 20 are located on the same plane. The display screen 20 includes multiple arrayed LED units 201. Each LED unit 201 emits light of a first color, and each LED unit 201 is individually driven through a corresponding contact 101.

[0084] Referring to Figures 8 and 9, the specific steps for forming the display screen 20 include: etching the LED epitaxial layer 901 to form multiple LED units 201, the LED units 201 being arrayed on the bonding layer 40, and the MESA pattern being designed according to the patterned mask, and etching the LED epitaxial layer 901 to form multiple stepped LED units 201.

[0085] S500, a passivation layer 203 is formed on the side of the first LED unit 201 and the side of the bonding layer 40. The passivation layer 203 is formed by deposition, sputtering or other methods. The passivation layer 203 can be used to form a protective structure on the surface of the LED unit 201 to prevent contaminants from being sputtered onto the surface of the LED unit 201 during subsequent etching.

[0086] In step S600, an electrode layer 204 is formed on the side of the passivation layer 203 away from the LED unit 201. The electrode layer 204 is electrically connected to the corresponding contact 101 and the top surface of the LED unit 201, respectively. The passivation layer 203 electrically isolates the electrode layer 204 from either the LED unit 201 or the bonding layer 40. For example, the electrode layer 204 is made of a transparent conductive material.

[0087] S700, referring to Figures 8 and 9, a light-emitting hole 2041 is formed on the electrode layer 204 at the position corresponding to the top surface of the LED unit 201, and an etching barrier layer 50 is formed on the surface of the electrode layer 204 on the side away from the driving substrate 10.

[0088] The etching barrier layer 50 fills the light emission hole 2041 and covers the top surface of the electrode layer 204 and the LED unit 201. The light emission hole 2041 can be formed by dry etching. The etching barrier layer 50 is used to protect the LED unit 201 when the grid layer 202 is formed subsequently.

[0089] S800, a grid layer 202 is formed on the side surface of the driving substrate 10 facing the display screen 20, and a plurality of grid holes 2021 corresponding to the LED units 201 are formed on the grid layer 202, and the plurality of LED units 201 are disposed in the corresponding grid holes 2021.

[0090] The grid aperture 2021 can be formed by dry etching. The grid aperture 2021 is used for the emission of light emitted by the LED unit 201, and is also used for subsequent filling of different wavelength conversion units to achieve the conversion of different colors of light.

[0091] In at least one embodiment of this application, referring to FIG9, after the step of forming the grid layer 202, the fabrication method may further include: forming a reflective layer 205 on the sidewall of the grid hole 2021 and on the surface of the grid layer 202 away from the driving substrate 10, wherein an etching barrier layer 50 is located between the reflective layer 205 and the electrode layer 204, and the etching barrier layer 50 electrically isolates the reflective layer 205 and the electrode layer 204.

[0092] In at least one embodiment of this application, referring to Figures 1 and 10, the fabrication method may further include: forming a wavelength conversion layer 30 on the side of the display screen 20 away from the driving substrate 10, the wavelength conversion layer 30 including a first wavelength conversion unit 301 and a second wavelength conversion unit 302; forming a first display module 100 by correspondingly distributing the first wavelength conversion unit 301 on all LED units 201 in one display screen 20, the first wavelength conversion unit 301 being capable of converting first color light into second color light; forming a second display module 200 by correspondingly distributing the second wavelength conversion unit 302 on all LED units 201 in another display screen 20, the second wavelength conversion unit 302 being capable of converting first color light into third color light.

[0093] For example, the wavelength conversion layer 30 may also include a third wavelength conversion unit 303, and the third wavelength conversion unit 303 is correspondingly disposed on all LED units 201 in another display screen 20 to form a third display module 300. The third wavelength conversion unit 303 can convert the first color light into the fourth color light.

[0094] It is understood that the method of this application separates multiple processing areas 400 on the driving substrate 10 and realizes the fabrication of multiple display screens 20 on the same plane. The highly integrated LED unit 201 can improve the compactness and space utilization of the chip, and the display module design is completed by combining with the wavelength conversion layer 30, realizing the chip's multiple color display and improving the color display capability of the display chip.

[0095] In at least one embodiment of this application, the step of forming the wavelength conversion layer 30 further includes: filling all the grid holes 2021 in the grid layer 202 of a display screen 20 with a first wavelength conversion unit 301; filling all the grid holes 2021 in the grid layer 202 of another display screen 20 with a second wavelength conversion unit 302; and filling all the grid holes 2021 in the grid layer 202 of another display screen 20 with a third wavelength conversion unit 303; wherein, any display screen 20 emits light of one color.

[0096] In at least one embodiment of this application, referring to FIG1, after the step of forming the wavelength conversion layer 30, the fabrication method may further include: forming a first filter layer 60 on the surface of the first wavelength conversion unit 301 away from the LED unit 201, the first filter layer 60 being used to filter other colors of light and allow second colors of light to pass through; forming a second filter layer 70 on the surface of the second wavelength conversion unit 302 away from the LED unit 201, the second filter layer 70 being used to filter other colors of light and allow third colors of light to pass through; and forming a third filter layer 80 on the surface of the third wavelength conversion unit 303 away from the LED unit 201, the third filter layer 80 being used to filter other colors of light and allow fourth colors of light to pass through.

[0097] It should be noted that the embodiments of this application do not specifically limit the order of steps in the fabrication method of the micro light-emitting diode display chip.

[0098] The embodiments of the manufacturing method in this application only describe the manufacturing process or steps. Device structures, shapes, and materials not described can be referred to the above embodiments of the micro light-emitting diode display chip, and will not be repeated here.

[0099] Referring to Figures 11 and 12, this application provides a display device, which includes the aforementioned micro light-emitting diode display chip and a light-combining module 2. Furthermore, the light-emitting direction of the display screen 20 is defined as a first direction X, and the direction in which at least two of the first display module 100, the second display module 200, and the third display module 300 are spaced apart is defined as a second direction Y. The first direction X intersects the second direction Y, and the display chip and the light-combining module 2 are correspondingly arranged in the first direction X.

[0100] In at least one embodiment of this application, referring to FIG11, the light combining module 2 includes a first light combining unit 21 and a second light combining unit 22 located on the same plane and spaced apart along the second direction Y; the first light combining unit 21 is correspondingly disposed with the first display module 100 in the first direction X, and the first light combining unit 21 is used to convert the second color light from the first direction X to the second direction Y for emission; the second light combining unit 22 is correspondingly disposed with the second display module 200 in the first direction X, and the second light combining unit 22 is used to convert the third color light from the first direction X to the second direction Y for emission, and to allow the second color light emitted along the second direction Y to pass through. The light combining module 2 also includes a third light combining unit 23, which is located on the same plane as the first light combining unit 21 and the second light combining unit 22, and is disposed along the second direction Y on the side of the second light combining unit 22 away from the first light combining unit 21; the third light combining unit 23 is correspondingly disposed with the third display module 300 in the first direction X, and is used to convert the fourth color light from the first direction X to the second direction Y for emission, and to allow either the second color light or the third color light emitted along the second direction Y to pass through.

[0101] It is understandable that by placing display modules emitting different colors of light on the same driving substrate 10, the light emitted by the display modules is already aligned on the surface along the second direction Y. The light combining of multiple colors of light can be completed simply by adjusting the angle and distance between the first light combining unit 21, the second light combining unit 22, and the third light combining unit 23. Compared with the light combining structure of multiple independent display chips through prisms, the alignment difficulty of this application is greatly improved, and the structure of the light combining module 2 is simpler and has a wide range of applications.

[0102] In at least one embodiment of this application, taking FIG11 as an example, the display device is not only used for three-color light combining, but the driving substrate 10 is not limited to three colors, nor is it limited to three display modules.

[0103] Specifically, the color combinations on the driving substrate can be as follows: the first display module 100, the second display module 200, and the third display module 300 all emit light of one color, such as red, green, or blue, to enhance the brightness of monochromatic light; or the first display module 100 emits red light, the second display module 200 emits green light, and the third display module 300 emits blue light to achieve full-color display by combining three colors; or the number of display modules is greater than three, with three of them emitting red, green, and blue light respectively, and one display module emitting white light to enhance the brightness of the combined three colors; or the number of display modules is greater than three, with two of them emitting red light, one emitting green light, and one emitting blue light, with the additional red-emitting display module compensating for the weak red light output.

[0104] In at least one embodiment of this application, referring to FIG12, the first light combining unit 21 has a first optical film 211 facing the first display module 100, and the orthographic projection of the first optical film 211 on the driving substrate 10 along the first direction X covers the first display module 100; the second light combining unit 22 has a second optical film 221 facing the second display module 200, and the orthographic projection of the second optical film 221 on the driving substrate 10 along the first direction X covers the second display module 200; the third light combining unit 23 has a third optical film 231 facing the third display module 300, and the orthographic projection of the third optical film 231 on the driving substrate 10 along the first direction X covers the third display module 300.

[0105] In some embodiments, any one of the first optical film 211, the second optical film 221, and the third optical film 231 is inclined relative to the surface of the driving substrate 10, and the first optical film 211, the second optical film 221, and the third optical film 231 are arranged parallel to each other. It is understood that the inclination angle is in the range of 30 to 60°, which can ensure the stability of light combining.

[0106] In some embodiments, the first optical film 211, the second optical film 221, and the third optical film 231 may be polarizing beam splitters. A polarizing beam splitter is a composite film of multilayer metal or semiconductor materials, which achieves polarization and spectral separation of light by utilizing the interference effect of multilayer films.

[0107] In some embodiments, the surfaces of the first light-combining unit 21, the second light-combining unit 22, and the third light-combining unit 23 may also be made of a single-sided highly reflective transparent material, and the second light-combining unit 22 and the third light-combining unit 23 also need to be made of a material with high transmittance to facilitate the transmission of the first color light and the second color light. Specifically, the high transmittance material may include transparent glass, silicon nitride, etc.

[0108] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0109] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of the present application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions 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 application.

Claims

1. A miniature light-emitting diode display chip, comprising: A driving substrate, the driving substrate including multiple contacts; Multiple displays are spaced apart on the driving substrate and located on the same plane. Each display includes multiple LED units arranged in an array. Each LED unit is used to emit light of a first color and is driven individually through a corresponding contact. A wavelength conversion layer is disposed on the side of the display screen away from the driving substrate. The wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit. The first wavelength conversion unit is configured with all the LED units in one display screen to form a first display module. The first wavelength conversion unit converts the first color light into a second color light. The second wavelength conversion unit is configured with all the LED units in another display screen to form a second display module. The second wavelength conversion unit converts the first color light into a third color light.

2. The micro light-emitting diode display chip according to claim 1, wherein the wavelength conversion layer further comprises a third wavelength conversion unit, the third wavelength conversion unit and all the LED units in the other display screen are correspondingly configured to form a third display module, and the third wavelength conversion unit converts the first color light into a fourth color light. 3.The micro light emitting diode display chip of claim 1 or 2, wherein, The display screen also includes: A grid layer, the grid layer being located on the side surface of the driving substrate facing the wavelength conversion layer; The grid layer has a plurality of grid holes corresponding to the LED units, the LED units are disposed in the corresponding grid holes, and the first wavelength conversion unit and the second wavelength conversion unit fill the corresponding grid holes.

4. The micro light emitting diode display chip of claim 3, wherein, The display screen also includes: A bonding layer is disposed between the driving substrate and the LED unit, and the LED unit is electrically connected to the bonding layer; A reflective layer that at least covers the sidewalls of the grid apertures.

5. The micro light emitting diode display chip of claim 4, wherein, The display screen also includes: A passivation layer covering the side of the LED unit; An electrode layer covers the side of the passivation layer away from the LED unit. The electrode layer is electrically connected to the top surface of the driving substrate and the LED unit, respectively. The passivation layer electrically isolates the electrode layer from the LED unit. The passivation layer also covers the sidewall of the bonding layer and electrically isolates the electrode layer from the bonding layer. An etch barrier layer is located on the side surface of the electrode layer facing the wavelength conversion layer. The electrode layer also has a light-emitting aperture that exposes the LED unit. The etch barrier layer fills the light-emitting aperture and covers the top surface of the LED unit. The etch barrier layer is located between the reflective layer and the electrode layer and electrically isolates the reflective layer and the electrode layer.

6. The miniature light-emitting diode display chip according to any one of claims 1 to 5, further comprising: A first filter layer is located on the surface of the first wavelength conversion unit away from the LED unit. The first filter layer is used to filter other colors of light and allow the second color of light to pass through. The second filter layer is located on the surface of the second wavelength conversion unit away from the LED unit. The second filter layer is used to filter other colors of light and allow the third color of light to pass through.

7. The micro light-emitting diode display chip according to claim 6 further includes a third filter layer, the third filter layer being located on the surface of the third wavelength conversion unit away from the LED unit, the third filter layer being used to filter other colors of light and allow the fourth color of light to pass through. 8.The micro light emitting diode display chip of any one of claims 1-7, wherein, The LED unit has a stepped structure, which includes a first doped semiconductor layer, a second doped semiconductor layer, and an active layer located between the two. The stepped structure disconnects and electrically isolates adjacent second doped semiconductor layers, active layers, and first doped semiconductor layers from each other, and the contacts are electrically connected to the corresponding first doped semiconductor layers.

9. The miniature light-emitting diode display chip according to any one of claims 1 to 8, The size of the LED unit is 0.1–10 μm; and / or The driving substrate is a silicon-based CMOS driving board or a thin-film field-effect transistor driving board.

10. A method for fabricating a miniature light-emitting diode display chip, comprising: A driving substrate is provided, the driving substrate including a plurality of contacts; An LED epitaxial layer is formed on the driving substrate; The LED epitaxial layer is divided into multiple processing areas, and the LED epitaxial layer of each processing area is etched to form a display screen. The multiple display screens are located on the same plane. The display screen includes multiple LED units arranged in an array. The LED units are used to emit light of a first color, and the LED units are individually driven through corresponding contacts. A wavelength conversion layer is formed on the side of the display screen away from the driving substrate. The wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit. In one display screen, the first wavelength conversion unit is correspondingly disposed on all the LED units to form a first display module. The first wavelength conversion unit converts the first color light into a second color light. In another display screen, the second wavelength conversion unit is correspondingly disposed on all the LED units to form a second display module. The second wavelength conversion unit converts the first color light into a third color light.

11. The method for fabricating a micro light-emitting diode display chip according to claim 10, wherein, The wavelength conversion layer further includes a third wavelength conversion unit. The third wavelength conversion unit is correspondingly disposed on all the LED units in another display screen to form a third display module. The third wavelength conversion unit converts the first color light into a fourth color light.

12. The method for fabricating a micro light-emitting diode display chip according to claim 10 or 11, wherein, The step of forming the LED epitaxial layer on the driving substrate includes: A substrate is provided, on which an LED epitaxial layer is provided; A bonding layer is formed on the driving substrate and / or the LED epitaxial layer; The driving substrate and the LED epitaxial layer are bonded together through the bonding layer; Remove the substrate.

13. The method for fabricating a micro light-emitting diode display chip according to claim 12, wherein, The step of etching the LED epitaxial layer in each of the processing areas to form a display screen includes: The LED epitaxial layer is etched to form a plurality of LED units, and the LED units are arranged in an array on the bonding layer; A grid layer is formed on the side surface of the driving substrate facing the display screen, and a plurality of grid holes corresponding to the LED units are formed on the grid layer, and the plurality of LED units are disposed in the corresponding grid holes; A reflective layer is formed on the sidewall of the grid hole and on the surface of the grid layer away from the driving substrate.

14. The method for fabricating a micro light-emitting diode display chip according to claim 13, wherein, The step of etching the LED epitaxial layer in each of the processing areas to form a display screen further includes: A passivation layer is formed on the side of the LED unit and on the side of the bonding layer; An electrode layer is formed on the side of the passivation layer away from the LED unit. The electrode layer is electrically connected to the top surface of the driving substrate and the LED unit, respectively. The passivation layer electrically isolates the electrode layer from either the LED unit or the bonding layer. A light-emitting hole is formed at the position of the electrode layer corresponding to the top surface of the LED unit, and an etching barrier layer is formed on the surface of the electrode layer away from the driving substrate. The etching barrier layer fills the light-emitting hole and covers the top surface of the electrode layer and the LED unit. The etching barrier layer is located between the reflective layer and the electrode layer, and the etching barrier layer electrically isolates the reflective layer and the electrode layer.

15. The method for fabricating a micro light-emitting diode display chip according to any one of claims 10 to 14, wherein the step of forming the wavelength conversion layer comprises: A first wavelength conversion unit is filled in all the grid holes in the grid layer of the display screen; and / or A second wavelength conversion unit is filled in all the grid holes in the grid layer of another display screen.

16. The method of claim 10 to 15, wherein, After the step of forming the wavelength conversion layer, the fabrication method further includes: A first filter layer is formed on the surface of the first wavelength conversion unit on the side away from the LED unit. The first filter layer is used to filter other colors of light and allow the second color of light to pass through. A second filter layer is formed on the surface of the second wavelength conversion unit away from the LED unit. The second filter layer is used to filter other colors of light and allow the third color of light to pass through.

17. The method for fabricating a micro light-emitting diode display chip according to claim 16, wherein, After the step of forming the wavelength conversion layer, the fabrication method further includes: A third filter layer is formed on the surface of the third wavelength conversion unit on the side away from the LED unit. The third filter layer is used to filter other colors of light and allow the fourth color of light to pass through.

18. A display device comprising a micro light-emitting diode display chip according to any one of claims 1 to 9; or comprising a micro light-emitting diode display chip obtained by the preparation method according to any one of claims 10 to 17.

19. The display device of claim 18, in the micro light emitting diode display chip, a light emitting direction of the display screen is a first direction, a direction in which at least two of the first display module, the second display module, and the third display module are spaced apart is a second direction, the first direction intersects the second direction, and wherein, The display device further includes: A light combining module, the light combining module comprising a first light combining unit and a second light combining unit located on the same plane and spaced apart along the second direction; The first light combining unit and the first display module are respectively arranged in the first direction. The first light combining unit is used to convert the second color light from the first direction to the second direction for emission. The second light combining unit and the second display module are respectively arranged in the first direction. The second light combining unit is used to convert the third color light from the first direction to the second direction for emission, and to allow the second color light emitted along the second direction to pass through.

20. The display device of claim 19, wherein, The light combining module further includes a third light combining unit, which is located on the same plane as the first light combining unit and the second light combining unit, and is disposed along the second direction on the side of the second light combining unit away from the first light combining unit. The third light combining unit and the third display module are arranged correspondingly in the first direction. The third light combining unit is used to convert the fourth color light from the first direction to the second direction for emission, and to allow either the second color light or the third color light emitted along the second direction to pass through.

21. The display device according to claim 20, wherein, The first light combining unit has a first optical film facing the first display module, and the first optical film covers the first display module by an orthogonal projection on the driving substrate along the first direction; The second light combining unit has a second optical film facing the second display module, and the orthographic projection of the second optical film on the driving substrate along the first direction covers the second display module; The third light combining unit has a third optical film facing the third display module, and the orthogonal projection of the third optical film on the driving substrate along the first direction covers the third display module.

22. The display device of claim 21, wherein, The first optical film, the second optical film, and the third optical film are inclined relative to the surface of the driving substrate, and the first optical film, the second optical film, and the third optical film are arranged parallel to each other.

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