Display device

Abstract

The display device includes a driving substrate, a plurality of micro light-emitting elements, and a common electrode. The micro light-emitting elements are dispersedly disposed on the driving substrate, and grooves are provided on the driving substrate between the micro light-emitting elements. Each micro light-emitting element includes an epitaxial structure layer and a first electrode and a second electrode disposed on opposite sides of the epitaxial structure layer. The common electrode is disposed on the driving substrate and located between the first electrodes of the micro light-emitting elements. The common electrode exposes an upper surface of the first electrode. The sidewalls of the micro light-emitting elements are covered with an insulating layer that extends into the groove to improve device reliability.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing, specifically relating to a display device that uses miniature light-emitting diodes as display pixels. Background Technology

[0002] In recent years, light-emitting diodes (LEDs) have been widely used in lighting and other fields due to their unique advantages, and have replaced traditional lighting sources. With technological advancements, micro LEDs, with their advantages of low power consumption, high brightness, ultra-high resolution, ultra-high color saturation, fast response speed, low energy consumption, and long lifespan, are gradually becoming the light-emitting components in next-generation displays. However, the miniaturization of micro LEDs has increased the difficulty of manufacturing processes, and improving device reliability and reducing production costs are particularly important topics within the industry. Summary of the Invention

[0003] This invention provides a solution for improving the mass production of micro-display devices, particularly focusing on solving product reliability issues and reducing the overall manufacturing cost of the solution.

[0004] In some embodiments, a display device includes: a driving substrate for providing driving control, a plurality of micro light-emitting elements as a display light source, and a common electrode for providing current to the micro light-emitting elements. The micro light-emitting elements are dispersedly disposed on the driving substrate. Each micro light-emitting element includes an epitaxial structure layer for providing hole recombination and a first electrode and a second electrode disposed on opposite sides of the epitaxial structure layer. The common electrode is located between the first electrodes of the micro light-emitting elements and is electrically connected to the first electrodes. A groove is provided on the driving substrate between the micro light-emitting elements. The sidewalls of the micro light-emitting elements are covered with an insulating layer that extends into the groove. By covering the groove with the insulating layer, the reliability of the device is improved in the field of ultra-small pitch displays.

[0005] Based on the above-described embodiments, and due to the design of the present invention, the present invention has better reliability and enhances the prospects for the large-scale application of micro-display devices. To make the above-described features and advantages of the present invention more apparent and understandable, embodiments are listed below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0007] Figure 1This is a cross-sectional structural schematic diagram of Embodiment 1 of the present invention;

[0008] Figure 2 This is a top view of the structure of Embodiment 1 of the present invention;

[0009] Figure 3 This is an enlarged cross-sectional view of the groove in Embodiment 1 of the present invention;

[0010] Figure 4 This is a cross-sectional structural schematic diagram of Embodiment 2 of the present invention;

[0011] Figure 5 This is a cross-sectional structural schematic diagram of Embodiment 3 of the present invention;

[0012] Figure 6 This is a cross-sectional structural schematic diagram of Embodiment 4 of the present invention;

[0013] Figure 7 This is a cross-sectional structural schematic diagram of Embodiment 5 of the present invention;

[0014] Figure 8 This is a cross-sectional structural schematic diagram of Embodiment 6 of the present invention;

[0015] Figure 9 This is a cross-sectional structural schematic diagram of Embodiment 7 of the present invention;

[0016] Figure 10 This is a cross-sectional structural schematic diagram of Embodiment 8 of the present invention;

[0017] Figure 11 This is a cross-sectional structural diagram of Embodiment 9 of the present invention.

[0018] The diagram shows the following labels: 100, driving substrate; 110, conductive contact; 120, groove; 200, common electrode; 210, common electrode reflective layer; 300, epitaxial structure layer; 310, first semiconductor layer; 320, second semiconductor layer; 330, active layer; 410, first electrode; 420, second electrode; 420', support layer; 421, metal bonding layer; 422, metal barrier layer; 423, metal reflective layer; 500, insulating layer; 600, isolation groove. Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] In some embodiments, a display device includes: a driving substrate for providing driving control, a plurality of micro light-emitting elements as a display light source, and a common electrode for providing current to the micro light-emitting elements. The micro light-emitting elements are dispersedly disposed on the driving substrate. Each micro light-emitting element includes an epitaxial structure layer for providing hole recombination and a first electrode and a second electrode disposed on opposite sides of the epitaxial structure layer. The common electrode is located between the first electrodes of the micro light-emitting elements and is electrically connected to the first electrodes. A groove is provided on the driving substrate between the micro light-emitting elements. An insulating layer is covered on the sidewall of the micro light-emitting elements and extends into the groove. The groove serves as a current blocking groove. The insulating layer covers the groove, improving device reliability in the field of ultra-small pitch displays.

[0021] In some embodiments, preferably, the insulating layer contacts the groove, the groove depth is greater than 100 nanometers and less than 1000 nanometers, thereby improving the sealing properties of the insulating layer.

[0022] In some embodiments, preferably, the groove has a V-shaped or U-shaped profile, and the insulating layer extends through the smooth sidewalls of the groove.

[0023] In some embodiments, preferably, the minimum spacing between the micro-light-emitting elements is 0.1 micrometers to 2 micrometers, thereby increasing the display pixels.

[0024] In some embodiments, preferably, the common electrode and the first electrode are an integral structure. The common electrode material includes a transparent conductive layer or a metal layer. From a top view, the common electrode is in the shape of a grid. An integral structure means that the same material is used or the same process is used to manufacture them simultaneously.

[0025] In some embodiments, preferably, the second electrode is at least partially located between the epitaxial structure layer and the driving substrate, and the micro light-emitting element is bonded to the driving substrate through the second electrode, for example, the second electrode is disposed below the epitaxial structure layer.

[0026] In some embodiments, preferably, the projected area of ​​the second electrode, viewed from above, is 0.5 square micrometers to 10 square micrometers. For example, the projected area of ​​the bonding metal layer in the second electrode is no more than 10 square micrometers. With the trend of miniaturization design of micro light-emitting elements, the size of the second electrode will be further reduced.

[0027] In some embodiments, preferably, the insulating layer within the groove is V-shaped or U-shaped, and maintaining smooth groove sidewalls helps to improve the barrier properties of the insulating layer.

[0028] In some embodiments, preferably, an isolation groove is provided between the micro light-emitting elements, and a recess is provided in the isolation groove, for example, the recess is provided in the middle of adjacent micro light-emitting elements.

[0029] In some embodiments, preferably, the projected area of ​​the second electrode, viewed from above, is 0.3 to 0.8 times, or 0.8 to 1 times, the projected area of ​​the micro-light-emitting element. In some processes, the second electrode is reduced in size, but the support reliability will decrease.

[0030] In some embodiments, preferably, an insulating layer is disposed on a driving substrate and at least partially covers the first electrode of each micro light-emitting element, while a common electrode is located on the insulating layer and disposed on the upper surface of the first electrode.

[0031] In some embodiments, preferably, the transmittance of the common electrode is less than that of the first electrode, thereby reducing light absorption by the common electrode.

[0032] In some embodiments, preferably, the insulating layer extends sequentially from the sidewall of the epitaxial structure layer, the sidewall of the second electrode, to the sidewall of the groove. The insulating layer is an insulating inorganic material or an insulating organic material. The angle between the sidewall of the epitaxial structure layer and the horizontal plane is α1, the angle between the sidewall of the second electrode and the horizontal plane is α2, and the angle between the sidewall of the groove and the horizontal plane is α3. α1, α2, and α3 are between 30° and 80°, and the difference between α1 and α2, and the difference between α2 and α3, is no greater than 20°. By utilizing the consistent sidewall design of each layer structure, a smooth transition of the insulating layer covering the sidewall is achieved, improving the reliability of the insulating layer.

[0033] In some embodiments, preferably, the epitaxial structure layer includes a first semiconductor layer, a second semiconductor layer, and an active layer located between the two, wherein the first semiconductor layer is electrically connected to a first electrode, the second semiconductor layer is electrically connected to a second electrode, the first electrode is an N-type electrode, and the second electrode is a P-type electrode.

[0034] In some embodiments, preferably, the insulating layer fills the groove, thereby improving the reliability of the micro-light-emitting element. Since the common electrode covers the insulating layer, as in this embodiment, the common electrode is not placed inside the groove, thus avoiding poor continuity of the common electrode within the small space of the groove.

[0035] In some embodiments, preferably, a metal filling layer is further included, one side of which partially or completely fills the isolation groove, and at least part of the other side of the metal filling layer covers the micro light-emitting element. An insulating layer and / or a common electrode are disposed between the upper surface of the epitaxial structure layer and the metal filling layer, and a snap-fit ​​structure is formed by utilizing the metal filling layer to improve the strength of the device.

[0036] In some embodiments, preferably, the second electrode includes a metal reflective layer, a metal barrier layer, or a metal bonding layer. The material of the metal bonding layer includes gold, tin, a nickel-tin mixture, or a gold-tin mixture. However, when the metal barrier layer includes tin, the reliability of the display product is prone to decrease during use. Therefore, the insulating layer laying method of this embodiment is preferred.

[0037] In some embodiments, preferably, the insulating layer extends sequentially from the sidewall of the epitaxial structure layer, the sidewall of the metal bonding layer, to the sidewall of the groove. The angle between the sidewall of the epitaxial structure layer and the horizontal plane is α1, the angle between the sidewall of the metal bonding layer and the horizontal plane is α2', and the angle between the sidewall of the groove and the horizontal plane is α3. α1, α2', and α3 are between 30° and 80°, and the difference between α1 and α2' and the difference between α2' and α3 is no greater than 20°. This reduces the angular difference between the sidewalls of the micro-light-emitting element and improves the isolation characteristics of the insulating layer.

[0038] In some embodiments, preferably, the metal bonding layer spacing between two adjacent micro-light-emitting elements is 0.1 micrometers to 2 micrometers, or 2 micrometers to 5 micrometers. Under the reliability design of this embodiment, reducing the metal bonding layer spacing to 0.1 micrometers to 2 micrometers can improve display pixels, but it also necessitates improving the reliability of the insulating layer.

[0039] In some embodiments, preferably, the edge of the metal bonding layer contacts the groove opening, and at the contact position, the sidewall of the metal bonding layer and the sidewall of the groove form a continuous surface, and the difference in the inclination angle of the sidewall of the metal bonding layer and the sidewall of the groove about the horizontal plane is not greater than 20°, thereby improving the adhesion of the insulating layer and avoiding large-angle bends in the insulating layer on the surface of the driving substrate.

[0040] In some embodiments, the driving substrate is a metal oxide semiconductor substrate, a silicon-based liquid crystal substrate, or a thin-film transistor substrate.

[0041] For details, see Figure 1 and Figure 2In a first embodiment of the present invention, a display device includes: a driving substrate 100 providing driving control, a plurality of micro-light-emitting elements serving as a display light source, and a common electrode 200 providing current to the micro-light-emitting elements. The micro-light-emitting elements are dispersedly disposed on the driving substrate 100, and each micro-light-emitting element constitutes a pixel. The display device can be a micro-light-emitting diode display (Micro LED Display), and the driving substrate 100 can be a metal-oxide-semiconductor substrate, a silicon-based liquid crystal substrate, or a thin-film transistor substrate. The cross-section in the figure shows three micro-light-emitting elements as an example, but the number of micro-light-emitting elements is not limited to this. The minimum spacing between the micro-light-emitting elements is 0.1 micrometers to 2 micrometers. Theoretically, the smaller the spacing, the better the display pixels.

[0042] Each micro-light-emitting element includes an epitaxial structure layer 300 for providing hole recombination and a first electrode 410 and a second electrode 420 disposed on opposite sides of the epitaxial structure layer 300. The first electrode 410 is located above the epitaxial structure layer 300, and the second electrode 420 is located below the epitaxial structure layer 300. The epitaxial structure layer 300 includes a first semiconductor layer 310, a second semiconductor layer 320, and an active layer 330 located between them. The first semiconductor layer 310 is electrically connected to the first electrode 410, and the second semiconductor layer 320 is electrically connected to the second electrode 420. The first electrode 410 is an N-type electrode, and the second electrode 420 is a P-type electrode. A conductive contact 110 is also provided within the driving substrate 100, and the conductive contact 110 is electrically connected to the second electrode 420.

[0043] A common electrode 200 is located between the first electrodes 410 of adjacent micro-light-emitting elements, and the common electrode 200 is electrically connected to the first electrode 410. In some embodiments, the common electrode 200 located between the micro-light-emitting elements may have a common electrode reflective layer 210 to improve light extraction efficiency. An isolation groove 600 is provided between the micro-light-emitting elements, extending towards the driving substrate and forming a recess on the driving substrate. A recess 120 is provided within the isolation groove 600, for example, the recess 120 is located at the middle position of adjacent micro-light-emitting elements. A recess 120 is provided on the driving substrate 100 between the micro-light-emitting elements, and the sidewalls of the micro-light-emitting elements are covered with an insulating layer 500, extending into the recess 120, covering or filling the recess 120 through the insulating layer 500. In some embodiments, the micro-light-emitting elements have a lens, which is disposed above the epitaxial structure layer 300 (not shown in the figure), and light is emitted from the lens.

[0044] The driving substrate 100 around the groove is non-conductive. By providing a groove 120 on the driving substrate 100 between adjacent light-emitting elements, the second electrodes 420 of the two adjacent light-emitting elements are isolated.

[0045] The second electrode 420 is at least partially located between the epitaxial layer 300 and the driving substrate 100. The micro-light-emitting element is bonded to the driving substrate 100 via the second electrode 420. The second electrode 420 can be composed of a single or multiple metals. Viewed from above, the projected area of ​​the second electrode 420 is 0.5 square micrometers to 10 square micrometers. For example, the projected area of ​​the bonding metal layer 421 in the second electrode 420 is no greater than 10 square micrometers. It is possible that with advancements in manufacturing processes and the trend towards miniaturization of micro-light-emitting elements, the size of the second electrode 420 will be further reduced. The projected area of ​​the second electrode 420 is 0.8 to 1 times the projected area of ​​the micro-light-emitting element.

[0046] The second electrode 420 includes a metal bonding layer 421, a metal barrier layer 422, or a metal reflective layer 423. The material of the metal bonding layer 421 includes gold, tin, a nickel-tin mixture, or a gold-tin mixture. When the metal barrier layer 422 includes tin, the reliability of the display product is prone to decrease during use. Therefore, the insulating layer 500 laying method of this embodiment is preferred. As the pixel count increases, the spacing between the micro-light-emitting elements gradually decreases. In this embodiment, the spacing of the metal bonding layer 421 between two adjacent micro-light-emitting elements is 0.1 micrometers to 2 micrometers, or 2 micrometers to 5 micrometers. Under the reliability design of this embodiment, reducing the spacing of the metal bonding layer 421 can improve the display pixel count.

[0047] An insulating layer 500 is disposed on the driving substrate 100 and at least partially covers the first electrode 410 of each micro light-emitting element, while a common electrode 200 is located on the insulating layer 500 and disposed on the upper surface of the first electrode 410. The transmittance of the common electrode 200 is less than that of the first electrode 410, thereby reducing the light absorption of the common electrode 200.

[0048] See in combination Figure 3 The insulating layer 500 contacts the groove 120, and the groove 120 has a depth d1 greater than 100 nanometers and less than 1000 nanometers, which improves the sealing performance of the insulating layer 500. The groove 120 has a V-shaped cross-section, and the insulating layer 500 extends through the smooth sidewalls of the groove 120. In some embodiments, the insulating layer 500 within the groove 120 is V-shaped, maintaining the smooth sidewalls of the groove 120. Alternatively, the insulating layer 500 can be provided by filling the groove 120 completely.

[0049] The insulating layer 500 extends sequentially from the sidewall of the epitaxial structure layer 300, the sidewall of the second electrode 420, to the sidewall of the groove 120. The insulating layer 500 is an insulating inorganic material or an insulating organic material. The angle between the sidewall of the epitaxial structure layer 300 and the horizontal plane is α1. Due to etching errors, in order to ensure a smooth transition between the layers, α1 is the angle between the bottom sidewall of the epitaxial structure layer 300 and the horizontal plane. The angle between the sidewall of the second electrode 420 and the horizontal plane is α2, which is the angle between the bottom sidewall of the second electrode 420 and the horizontal plane. The angle between the sidewall of the groove 120 and the horizontal plane is α3, which is the angle between the top of the sidewall of the groove 120 and the horizontal plane. α1, α2, and α3 are between 30° and 80°, and the difference between α1 and α2, and the difference between α2 and α3, is no greater than 20°. By utilizing the consistent sidewall design of each layer structure, a smooth transition of the insulating layer 500 covering the sidewalls is achieved, improving the reliability of the insulating layer 500.

[0050] In some embodiments, the insulating layer 500 extends sequentially from the sidewall of the epitaxial structure layer 300, the sidewall of the metal bonding layer 421, to the sidewall of the groove. The angle between the sidewall of the epitaxial structure layer 300 and the horizontal plane is α1, the angle between the sidewall of the metal bonding layer 421 and the horizontal plane is α2', and the angle between the sidewall of the groove 120 and the horizontal plane is α3. α1, α2', and α3 are between 30° and 80°, and the difference between α1 and α2' and the difference between α2' and α3 is no greater than 20°.

[0051] The edge of the metal bonding layer 421 contacts the opening of the groove 120, and at the contact position, the sidewall of the metal bonding layer 421 and the sidewall of the groove 120 form a continuous surface. The difference in the tilt angle between the sidewall of the metal bonding layer 421 and the sidewall of the groove 120 about the horizontal plane is no more than 20°, which improves the continuity of the insulating layer 500 and avoids large-angle bends in the insulating layer 500 on the surface of the drive substrate 100.

[0052] The minimum spacing between the metal bonding layers 421 of adjacent micro-light-emitting elements is d2. In this embodiment, d2 is also the minimum spacing between micro-light-emitting elements, ranging from 0.1 micrometers to 2 micrometers.

[0053] See Figure 4 In a second embodiment of the present invention, the groove 120 has a U-shaped cross-section, and the insulating layer 500 extends through the smooth sidewalls of the groove 120. The insulating layer 500 in the groove 120 is U-shaped, and the insulating layer 500 can be provided by filling the groove 120 to maintain the smooth sidewalls of the groove 120.

[0054] See Figure 5In the third embodiment of the present invention, the common electrode 200 and the first electrode 410 are integrally formed. The material of the common electrode 200 includes a transparent conductive layer or a metal layer. From a top view, the common electrode 200 has a mesh-like structure. The integral structure refers to the use of the same material or the simultaneous fabrication of the same process. This can reduce the need for a photomask design. The common electrode 200 extends from the isolation trench 600 to the surface of the epitaxial structure layer 300.

[0055] See Figure 6 In a fourth embodiment of the present invention, the common electrode 200 is positioned above the epitaxial structure layer 300 at a height greater than the epitaxial structure layer 300, for example, greater than the first semiconductor layer 310. The common electrode 200 can be made of metal. Due to the significantly increased density of light-emitting elements in microLED applications, and the difficulty in repairing malfunctioning light-emitting elements, heat dissipation and reliability are key indicators. In this embodiment, the common electrode 200 is extended from the area between the light-emitting elements to the upper surface of the microdisplay device above the epitaxial structure layer, thereby improving the overall heat dissipation characteristics of the device.

[0056] See Figure 7 In a fifth embodiment of the present invention, a metal filling layer is further included. The metal filling layer partially or completely fills the isolation trench 600, and at least a portion of the metal filling layer extends from the isolation trench 600 to cover the micro light-emitting element. An insulating layer 500 and / or a common electrode 200 are disposed between the upper surface of the epitaxial structure layer 300 and the metal filling layer. The metal filling layer forms a snap-fit ​​structure, improving the device strength. The design of the metal filling layer also provides a better heat dissipation solution.

[0057] See Figure 8 In a sixth embodiment of the present invention, the second electrode 420 and the groove 120 are spaced apart, for example, the metal bonding layer 421 and the groove 120 are spaced apart, and the insulating layer 500 partially covers the surface of the driving substrate 100. This embodiment can improve the bonding reliability between the device and the driving substrate 100, but it will reduce the reliability of the insulating layer 500.

[0058] See Figure 9 In the seventh embodiment of the present invention, the projected area of ​​the second electrode 420 is 0.3 to 0.8 times the projected area of ​​the micro light-emitting element. The supporting force provided by the second electrode 420 is reduced. By setting the insulating layer 500 and the groove 120 together, the overall device reliability is improved.

[0059] In some embodiments, the support layer 420' may not be limited to the second electrode 420. That is, the support layer 420' may be disposed below the epitaxial structure layer 300, and its conductivity characteristics may not be limited. For example, the first electrode 410 and the second electrode 420 may also be located on one side of the micro light-emitting element, while the support layer 420' is disposed independently.

[0060] See Figure 10 In the eighth embodiment of the present invention, as viewed from the projection, the bottom area of ​​the epitaxial structure layer 300 is smaller than the top area of ​​the second electrode 420. The insulating layer 500 covers a portion of the second electrode 420, for example, covering the metal reflective layer 423, the metal barrier layer 422, or the metal bonding layer 421. The portion above this portion is the surface of the top surface of the second electrode 420 exposed from the epitaxial structure layer 300.

[0061] See Figure 11 In the ninth embodiment of the present invention, the manufacturing process of the display device involves a removal process, such as dry etching or wet etching. In this embodiment, the tilt angle of each sidewall is controlled by the removal process. In this embodiment, the angle between the sidewall of the epitaxial structure layer 300 and the horizontal plane is set to α1, and the angle between the sidewall of the metal bonding layer 421 and the horizontal plane is set to α2'. In this embodiment, α1 < α2', for example, 0.5α2' ≤ α1 ≤ 0.9α2'. Setting the sidewall of the epitaxial structure layer 300 to be more gentle improves the coverage of the sidewall insulating layer 500 and improves the reliability of the device. Setting the sidewall of the metal bonding layer 421 to be steeper reduces the spacing between the micro light-emitting diodes, which helps to expand the light-emitting area of ​​the device under the requirement of ultra-small spacing.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and 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 invention.

Claims

1. A display device, comprising: a driving substrate, a plurality of micro light-emitting elements, and a common electrode, wherein the micro light-emitting elements are dispersedly disposed on the driving substrate, each micro light-emitting element includes an epitaxial structure layer and a first electrode and a second electrode disposed on opposite sides of the epitaxial structure layer, and the common electrode is located between the first electrodes of the micro light-emitting element and is electrically connected to the first electrodes, characterized in that, A groove is provided on the driving substrate between the micro light-emitting elements. The sidewalls of the micro light-emitting elements are covered with an insulating layer that extends into the groove. An isolation groove is provided between the micro light-emitting elements. The groove is located in the isolation groove. The angle between the sidewall of the groove and the horizontal plane is α3, where α3 is 30° to 80°.

2. The display device according to claim 1, characterized in that, An insulating layer covers the groove and is in contact with the groove. The groove depth is greater than 100 nanometers and less than 1000 nanometers.

3. A display device according to claim 1, characterized in that, The groove has a V-shaped or U-shaped cross-section.

4. A display device according to claim 1, characterized in that, The minimum spacing between micro-light-emitting elements is 0.1 micrometers to 2 micrometers.

5. A display device according to claim 1, characterized in that, The common electrode and the first electrode are integrated into one structure. The common electrode material includes a transparent conductive layer or a metal layer. When viewed from above, the common electrode has a grid-like structure.

6. A display device according to claim 1, characterized in that, The second electrode is located at least partially between the epitaxial structure layer and the driving substrate, and the micro light-emitting element is bonded to the driving substrate through the second electrode.

7. A display device according to claim 1, characterized in that, Viewed from above, the projected area of ​​the second electrode is 0.5 square micrometers to 10 square micrometers.

8. A display device according to claim 1, characterized in that, The insulating layer inside the groove is V-shaped or U-shaped.

9. A display device according to claim 1, characterized in that, Isolation grooves are provided between the miniature light-emitting elements, and the grooves are set inside the isolation grooves.

10. A display device according to claim 1, characterized in that, Viewed from above, the projected area of ​​the second electrode is 0.3 to 0.8 times, or 0.8 to 1 times, the projected area of ​​the micro light-emitting element.

11. A display device according to claim 1, characterized in that, An insulating layer is disposed on a driving substrate and at least partially covers the first electrode of each micro light-emitting element, while a common electrode is located on the insulating layer, the insulating layer covers the sidewall of the groove, and the common electrode is disposed on the upper surface of the first electrode, wherein the transmittance of the common electrode is less than that of the first electrode.

12. A display device according to claim 1, characterized in that, The insulating layer extends sequentially from the sidewall of the epitaxial structure layer, the sidewall of the second electrode, to the sidewall of the groove. The insulating layer is an insulating inorganic material or an insulating organic material. The angle between the sidewall of the epitaxial structure layer and the horizontal plane is α1, and the angle between the sidewall of the second electrode and the horizontal plane is α2. α1 and α2 are between 30° and 80°, and the difference between α1 and α2, and the difference between α2 and α3 are not greater than 20°.

13. A display device according to claim 1, characterized in that, The epitaxial structure layer includes a first semiconductor layer, a second semiconductor layer, and an active layer located between the two. The first semiconductor layer is electrically connected to a first electrode, and the second semiconductor layer is electrically connected to a second electrode. The first electrode is an N-type electrode, and the second electrode is a P-type electrode.

14. A display device according to claim 9, characterized in that, It also includes a metal filling layer, one side of which partially or completely fills the isolation groove, and at least part of the other side of the metal filling layer covers the micro light-emitting element. An insulating layer and / or a common electrode are disposed between the upper surface of the epitaxial structure layer and the metal filling layer.

15. A display device according to claim 1, characterized in that, The second electrode includes a metal reflective layer, a metal barrier layer, or a metal bonding layer, and the material of the metal bonding layer includes gold, tin, a mixture of nickel and tin, or a mixture of gold and tin.

16. A display device according to claim 15, characterized in that, The insulating layer extends sequentially from the sidewall of the epitaxial structure layer, the sidewall of the metal bonding layer, to the sidewall of the groove. The angle between the sidewall of the epitaxial structure layer and the horizontal plane is α1, and the angle between the sidewall of the metal bonding layer and the horizontal plane is α2'. α1 and α2' are between 30° and 80°, and the difference between α1 and α2' and the difference between α2' and α3 are both no greater than 20°.

17. A display device according to claim 16, characterized in that, The spacing between the metal bonding layers of two adjacent micro-light-emitting elements is 0.1 micrometers to 2 micrometers, or 2 micrometers to 5 micrometers, α1 < α2', 0.5α2' ≤ α1 ≤ 0.9α2'.

18. A display device according to claim 16, characterized in that, The edge of the metal bonding layer contacts the groove opening, and at the contact position, the sidewall of the metal bonding layer and the sidewall of the groove form a continuous surface, and the difference in the inclination angle of the sidewall of the metal bonding layer and the sidewall of the groove about the horizontal plane is no greater than 20°.

19. A display device according to claim 1, characterized in that, The driving substrate is a metal oxide semiconductor substrate, a silicon-based liquid crystal substrate, or a thin-film transistor substrate.

20. A display device, comprising: a driving substrate, a plurality of micro light-emitting elements, and a common electrode, wherein the micro light-emitting elements are dispersedly disposed on the driving substrate, each micro light-emitting element includes an epitaxial structure layer and a first electrode and a second electrode disposed on opposite sides of the epitaxial structure layer, and the common electrode is located between the first electrodes of the micro light-emitting element and is electrically connected to the first electrodes, characterized in that, An isolation groove is provided between the micro light-emitting elements. The isolation groove extends towards the driving substrate and forms a groove on the driving substrate. The sidewall of the micro light-emitting element is covered with an insulating layer and extends into the groove. The groove is set in the isolation groove. The angle between the sidewall of the groove and the horizontal plane is α3, where α3 is 30° to 80°.

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