Crosstalk-resistant microdisplay array

Abstract

The present application provides an anti-crosstalk micro-display array, including a substrate and a plurality of LED light-emitting devices arranged in an array on the substrate, wherein the plurality of LED light-emitting devices are divided into a plurality of independent islands by a plurality of isolation grooves, wherein the LED light-emitting device has a light-emitting layer and a distributed Bragg reflector layer, wherein the distributed Bragg reflector layer is located on the side of the light-emitting layer away from the light-emitting surface, and a plurality of reflective structures are periodically arranged on the substrate, wherein the reflective structures are located at the bottom of the isolation grooves and extend to the lower edge of the bottom surface of the LED light-emitting device, so that the light beam emitted from the edge of the bottom surface is reflected to the distributed Bragg reflector layer, and the edges of adjacent reflective structures define the light-emitting opening of the LED light-emitting device. The present application designs the reflective structures corresponding to the periodic arrangement according to the size of the LED light-emitting device, reflects the light emitted by the "illuminated" edge of the ISO step to the light-emitting area and then emits it, and finally limits the light-emitting range to the light-emitting opening, thereby eliminating stray light interference.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor micro-displays, and in particular relates to a micro-display array and a micro-display device. Background Art

[0002] Micro-LED (Micro Light Emitting Diode) display technology is the latest generation of display technology and has been a research hotspot in the field of display technology in recent years. Micro-LED is completely produced using solid-state semiconductor technology and has the advantages of small size, low power consumption, fast response speed, high contrast, and high color saturation. Its pixel size is mostly below 100 microns.

[0003] Since each LED device of the semiconductor micro display device can be controlled and turned off individually, it can obtain a pure black screen and better contrast. However, in the light-emitting area of ​​each LED device, the light emission and display effect are not uniform, which will appear Figure 1 In the display effect shown, the ISO (Isolation) steps between pixels and the ISO steps of the surrounding pixels will be "illuminated" by the light crosstalk emitted by the LED pixel light-emitting area, presenting a ring-shaped light-emitting area outside the normal light-emitting area, which will affect the display effect and may cause defects such as uneven brightness (mura). Summary of the invention

[0004] The purpose of the present application is to solve the problems of uneven light emitting effect and annular interference light in the micro display array in the prior art.

[0005] In order to achieve the purpose of the above invention, the present invention adopts the following technical scheme: an anti-crosstalk micro-display array, comprising a substrate and a plurality of LED light-emitting devices arranged in an array on the substrate, wherein the plurality of LED light-emitting devices are divided into a plurality of independent island portions by a plurality of isolation grooves, wherein the LED light-emitting device has a light-emitting layer and a distributed Bragg reflection layer, wherein the distributed Bragg reflection layer is located on the side of the light-emitting layer away from the light-emitting surface, and a plurality of reflective structures are periodically arranged on the substrate, wherein the reflective structure is located at the bottom of the isolation groove and extends to the lower edge of the bottom surface of the LED light-emitting device, so that a light beam emitted from the edge of the bottom surface is reflected to the distributed Bragg reflection layer, and the edges of the adjacent reflective structures define the light-emitting opening of the LED light-emitting device.

[0006] In one embodiment, the distributed Bragg reflection layer comprises two or more semiconductor or dielectric materials, and the total thickness of the distributed Bragg reflection layer is greater than 1 nm.

[0007] In one embodiment, the area of the distributed Bragg reflection layer is greater than or equal to the area of the light-emitting layer.

[0008] In one embodiment, the LED light-emitting device further has a plurality of side surfaces connecting the top surface and the bottom surface, wherein the projection of the side surfaces in the light-emitting direction falls on the bottom surface to form an annular light-emitting area with a width of W4, and the light-reflecting structure extends below the annular light-emitting area.

[0009] In one embodiment, the light-reflecting structure has a positive feature protruding upward from the surface of the substrate.

[0010] In one embodiment, the light-reflecting structure has a circular arc surface, and the normal vector of the circular arc surface points in a direction opposite to the light-emitting direction.

[0011] In one embodiment, the light-reflecting structure is ridge-shaped, and the normal vectors of the light-reflecting structure point to two adjacent LED light-emitting devices respectively.

[0012] In one embodiment, the light-reflecting structure is made of one of an organic material, an inorganic / organic laminated material, an organic / organic laminated material, or an inorganic / inorganic laminated material.

[0013] In one embodiment, the light-reflecting structure is made of one or more of Ag, Al, or an opaque metal composite layer material.

[0014] The advantages of the above solution are as follows: According to the size of the LED light-emitting device, the present application designs a corresponding periodically arranged light-reflecting structure, reflects the light emitted by the "illuminated" ISO step edge to the light-emitting area and then emits it again, and finally limits the light-emitting range within the light-emitting opening, thereby eliminating the interference of stray light. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 Is a photo of the light-emitting effect of the microdisplay array before improvement;

[0016] Attached Figure 2 Is a schematic structural diagram of a microdisplay array in an embodiment of the present application;

[0017] Attached Figure 3 Is a schematic structural diagram of a microdisplay array in another embodiment of the present application;

[0018] Wherein: 10, substrate; 11, light-reflecting structure; 12, high-reflection layer; 20, LED light-emitting device; 21, light-emitting layer; 22, Bragg light-reflecting layer; 23, ISO step; 24, top surface; 25, bottom surface; 26, side surface; 30, isolation trench. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To describe in detail the technical content, structural features, achieved objectives and effects of the invention, the following will be a detailed description in conjunction with embodiments and accompanied by drawings. Herein, the "upper" and "lower" positional relationships described in this specification respectively correspond to the upper and lower directions in the attached Figure 2 drawing, and the lower direction in the attached Figure 2 drawing is the light-emitting direction of the microdisplay array.

[0020] In addition, in this application, all spatial relative terms such as "top", "bottom", "under", "below", "beneath", "lower", "above", "upper", "over", "higher", "side" (for example, as in "side wall") are used to describe the relative positional relationship between one element and another (other) element as shown in the drawings. The spatial relative terms are intended to include different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the drawings. For example, if the device in the drawing is flipped, the element described as "under" or "beneath" other elements or features will subsequently be positioned "above" the said other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. In addition, the device can be positioned otherwise (for example, rotated 90 degrees or at other orientations), and accordingly, the spatial relative descriptive terms used herein are interpreted.

[0021] In this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a direct connection or an indirect connection through an intermediate medium.

[0022] The embodiments of this application disclose an anti-crosstalk microdisplay array. After being combined with a driving circuit, the microdisplay array together forms a microdisplay device. The microdisplay device of this embodiment can be applied to electronic devices such as AR / VR glasses, mobile phones, tablets, TVs, and computers.

[0023] When the applicant was studying the light-emitting structure of Micro-LED devices, it was found that the LED light-emitting devices presented Figure 1 the light-emitting effect as shown. It can be seen from the figure that the central area in the photo is the normal light-emitting area, and the annular light-emitting area surrounding the normal light-emitting area for one week is the light-emitting crosstalk area. The purpose of this application is to reduce this annular light-emitting area or prevent light from exiting from the light-emitting surface through this area. During further research, the applicant found that since the light-emitting direction of the LED is 360°, a considerable proportion of the light will irradiate on the side surface of the LED light-emitting device. At the same time, since the angle between the side surface of the epitaxial structure and the light-emitting surface is an acute angle, the light incident on the side surface is reflected and emitted towards the light-emitting surface, thereby forming an annular light-emitting crosstalk area around the normal light-emitting area, resulting in uneven light emission and light leakage.

[0024] Therefore, the present application proposes a crosstalk-proof microdisplay array, which is applicable to Mini-LED and Micro-LED.

[0025] Figure 2 This is an embodiment of the present application. As can be seen from the figure, the crosstalk-proof microdisplay array includes a substrate 10 and a plurality of LED light-emitting devices 20 arranged in an array on the substrate 10. The plurality of LED light-emitting devices 20 are divided into a plurality of independent island parts by a plurality of isolation trenches 30. The LED light-emitting device 20 has a light-emitting layer 21 and a distributed Bragg reflection layer 22 (DBR, Distributed Bragg reflection). The distributed Bragg reflection layer 22 is located above the light-emitting layer 21, and the LED light-emitting device 20 emits light from the lower side.

[0026] The LED light-emitting device 20 also has a plurality of side surfaces 26 connecting the top surface 24 and the bottom surface 25, wherein the area of the top surface 24 is smaller than the area of the bottom surface 25, and the LED light-emitting device 20 is generally in a trapezoidal structure.

[0027] A plurality of reflective structures 11 are periodically arranged on the substrate 10. These reflective structures 11 are located at the bottom of the isolation trench 30 and extend to the lower edge of the bottom surface 25 of the LED light-emitting device 20. That is, the reflective structure 11 is used to block the light emitted from the edge of the LED light-emitting device. The reason for such a setting is that there is a part of the light projected toward the side surface 26 in the light-emitting layer 21. Since the angle between the side surface 26 and the bottom surface is an acute angle, the light reflected by the side surface will be emitted toward the bottom surface 25 and exit through the bottom surface to form an annular light-emitting area. The reflective structure of the present application forms a block at the edge of the LED light-emitting device, so that the light beam emitted from the edge of the bottom surface 25 is reflected and incident into the LED light-emitting device 20 again, and is reflected by the distributed Bragg reflection layer 22 and then emitted downward again. Due to the limitation of the reflective structure, the LED light-emitting device 20 is defined by the edge of the adjacent reflective structure with a light-emitting opening, and the light emitted by the LED light-emitting device 20 can only be emitted toward the light-emitting side through the light-emitting opening.

[0028] In a specific embodiment, first, a periodically arranged positive feature is formed on the substrate by using a patterned sapphire substrate (PSS, Patterned Sapphire Substrate) with a specific design pattern and process, and then a reflective high-reflection layer 12 is formed on the surface of the positive feature by sputtering, CVD, PVD or other methods, thereby forming the reflective structure 11. The high-reflection layer 12 is made of one or more of Ag, Al or an opaque metal composite layer material.

[0029] In one embodiment of the present application, the distributed Bragg reflector layer 22 includes two or more semiconductor or dielectric materials, including a high refractive index layer and a low refractive index layer. The total thickness of the distributed Bragg reflector layer 22 > 1 nm, and the materials are semiconductor or dielectric materials. The film layers of the two materials with large and small refractive indices are alternately grown, and they are transparent to incident light. The greater the refractive index difference between the two materials used to fabricate the distributed Bragg reflector layer 22, the wider the reflection bandwidth of the distributed Bragg reflector layer 22, and the fewer the number of material pairs required to achieve a certain reflectivity. The distributed Bragg reflector layer 22 can not only reflect the light that enters the LED light-emitting device 20 through the light-reflecting structure back towards the light-emitting side, but also reflect the upward light emitted by the light-emitting layer 21 downward. The combination of the light-reflecting structure and the distributed Bragg reflector layer 22 can achieve the effect of reflecting the crosstalk light emitted by the non-light-emitting area of the ISO step 23 being "illuminated" by the crosstalk from the light-emitting area to the light-emitting area for light output.

[0030] In one embodiment of the present application, the area of the distributed Bragg reflector layer 22 is greater than or equal to the area of the light-emitting layer 21.

[0031] In one embodiment of the present application, the light-reflecting structure 11 has a positive feature that protrudes upward from the surface of the substrate 10, that is, the light-reflecting structure protrudes upward, so as to reflect the reflected light towards the direction of the LED light-emitting devices 20 on both sides. In other embodiments of the present application, the light-reflecting structure can also be planar, so that the light-reflecting structure can also reflect the reflected light at the edge of the LED light-emitting device upward.

[0032] Please continue to refer to Figure 2 , in one embodiment, the width of the light-reflecting structure in a row or column direction is W1, and the width of the bottom surface 25 of the LED light-emitting device 20 in this direction is W3. The width of the light-emitting opening on the bottom surface of the LED light-emitting device 20 is W2, and W2 ≤ W3. The projection of the side surface 26 in the light-emitting direction on the bottom surface 25 forms an annular light-emitting area with a width of W4. The light-reflecting structure extends below the annular light-emitting area and satisfies 2W4 + W2 ≥ W3.

[0033] In Figure 2 In the embodiment shown, the light-reflecting structure has a circular arc surface, the normal vector of the circular arc surface points in the direction opposite to the light-emitting direction, and the circular arc surface is a spherical surface.

[0034] In Figure 3 In the embodiment shown, the light-reflecting structure is ridge-shaped, and the normal vectors of the light-reflecting structure point to two adjacent LED light-emitting devices 20 respectively.

[0035] The light-emitting opening corresponds to a normally light-emitting area with uniform light emission and regular shape. Generally, the normally light-emitting area is square, rectangular, circular, hexagonal, etc., and each normally light-emitting area corresponds to a sub-pixel. The size of the light-emitting opening enables the light to be projected towards the substrate within the area of the light-emitting opening.

[0036] Among such LED light-emitting devices 20, the normal direction of the light-reflecting structure points to the side opposite to the light-emitting direction, which enables the light incident on the side surface to be reflected towards the inside of the LED light-emitting device and then to exit from the normally light-emitting area after being reflected by the distributed Bragg reflector layer. As can be seen from the figure, part of the light generated by the light-emitting layer 21 is obliquely incident on the side surface, reflected by the side surface and then exits towards the bottom surface; then it enters the LED light-emitting device again upwards through the light-reflecting structure, and is reflected by the distributed Bragg reflector layer, and finally exits from the light-emitting opening.

[0037] In an embodiment of the present application, the isolation trench 30 can also be filled with a light-absorbing material or a low-refractive-index dielectric material. For example, a dark organic glue can be filled, and the higher the blackness value, the better. The organic glue can be selected as photoresist, etc. When the light is transmitted through the side surface into the isolation trench, it will be absorbed, thus preventing the light from exiting towards the light-emitting side.

[0038] In the present application, by providing a light-reflecting structure on the light-emitting side of the LED light-emitting device, the emitted light is concentrated and emitted from the light-emitting opening, eliminating the annular light-emitting area outside the normally light-emitting area. In the display array, the edge of the island part formed by the epitaxial structure will not reflect or scatter light out from the light-emitting side, thus optimizing the problem of circular interference light.

[0039] The above has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements. The scope of protection required by the present invention is defined by the appended claims, the specification and their equivalents.

Claims

1. A crosstalk - resistant microdisplay array, characterized in that, The invention comprises a substrate (10) and a plurality of LED light-emitting devices (20) arranged in an array on the substrate (10), wherein the plurality of LED light-emitting devices (20) are divided into a plurality of independent island portions by a plurality of isolation grooves (30), wherein the LED light-emitting device (20) comprises a light-emitting layer (21) and a distributed Bragg reflection layer (22), wherein the distributed Bragg reflection layer (22) is located on a side of the light-emitting layer (21) away from a light-emitting surface, and wherein a plurality of reflective structures (11) are periodically arranged on the substrate (10), wherein the reflective structures (11) are located at the bottom of the isolation grooves (30) and extend to the bottom of the bottom surface (25) of the LED light-emitting device (20). The reflective structure (11) has a positive feature protruding upward from the surface of the substrate (10); the normal vector of the reflective structure (11) points in a direction opposite to the light emitting direction; the LED light emitting device (20) further has a plurality of side surfaces (26) connecting the top surface (24) and the bottom surface (25); the angle between the side surfaces (26) and the bottom surface is an acute angle; part of the light projected toward the side surfaces (26) of the light emitting layer (21) is reflected, so that the light beam emitted from the edge of the bottom surface (25) is reflected to the distributed Bragg reflection layer (22); and the edge of the adjacent reflective structure (11) defines a light emitting opening of the LED light emitting device (20).

2. The anti-crosstalk microdisplay array according to claim 1, wherein: The distributed Bragg reflection layer (22) comprises two or more semiconductor or dielectric materials, and the total thickness of the distributed Bragg reflection layer (22) is greater than 1 nm.

3. The anti-crosstalk microdisplay array according to claim 1, wherein: The area of ​​the distributed Bragg reflection layer (22) is greater than or equal to the area of ​​the light-emitting layer (21).

4. The anti-crosstalk microdisplay array according to claim 1, characterized in that: The projection of the side surface (26) in the light emitting direction falls on the bottom surface (25) to form an annular light emitting area with a width of W4, and the reflective structure extends to below the annular light emitting area.

5. The anti-crosstalk microdisplay array according to claim 1, wherein: The reflective structure (11) has an arc surface.

6. The anti-crosstalk microdisplay array according to claim 1, wherein: The reflective structure (11) is ridge-shaped, and the normal vectors of the reflective structure (11) point to two adjacent LED light-emitting devices (20) respectively.

7. The anti-crosstalk microdisplay array according to claim 1, characterized in that: The reflective structure (11) is made of one of organic materials, inorganic / organic laminated materials, organic / organic laminated materials or inorganic / inorganic laminated materials.

8. The anti-crosstalk microdisplay array according to claim 7, characterized in that: The reflective structure (11) is made of one or more of Ag, Al or an opaque metal composite layer material.

Images