Micro-led light emitting array structure

Abstract

This disclosure provides a MicroLED light-emitting array structure, which includes: a plurality of MicroLED pixel units arranged in an array structure with interconnected rows and columns; the MicroLED pixel unit includes: a substrate; a MicroLED pixel unit substrate formed on the substrate; and an absorption layer formed on the substrate, located on both sides of the MicroLED pixel unit substrate and above the surface of the MicroLED pixel unit substrate.

Description

Technical Field

[0001] This disclosure relates to the field of optoelectronic devices, and in particular to a MicroLED light-emitting array structure and its fabrication method, and a MicroLED display device. Background Technology

[0002] Light-emitting diodes (LEDs) are widely used in the field of solid-state lighting as the third generation of green light sources due to their high luminous efficiency and high brightness. They are also increasingly used in the field of flat panel displays due to their self-illumination, no viewing angle, and fast response, especially in the emerging field of miniature LEDs (Mini / MicroLEDs) flat panel displays in recent years.

[0003] MicroLED displays are primarily used in AR / VR headsets and wearable electronics. With a pixel pitch of less than 50µm and a chip spacing of less than 10µm, such small chip spacing leads to severe crosstalk in full-color displays. Furthermore, the micron-sized chips exhibit higher brightness at the edges than in the center, resulting in uneven brightness distribution and negatively impacting display quality. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of this, the main objective of this disclosure is to provide a MicroLED light-emitting array structure and its fabrication method, as well as a MicroLED display device, in order to at least partially solve at least one of the aforementioned technical problems.

[0006] (II) Technical Solution

[0007] According to one aspect of this disclosure, a MicroLED light-emitting array structure is provided, comprising:

[0008] Multiple MicroLED pixel units are arranged in an array structure with interconnected rows and columns; each MicroLED pixel unit includes: a substrate; a MicroLED pixel unit substrate formed on the substrate; and an absorption layer formed on the substrate, located on both sides of the MicroLED pixel unit substrate and above the surface of the MicroLED pixel unit substrate.

[0009] In some embodiments of this disclosure, the MicroLED pixel unit further includes: a reflective layer formed on the bottom of the substrate; the reflective layer is recessed by 2-8 μm relative to the bottom edge of the substrate; the reflective layer is made of a white polymeric organic material with a thickness of 20-40 μm, the white polymeric organic material including a white photosensitive cover film.

[0010] In some embodiments of this disclosure, the MicroLED pixel unit substrate includes: an epitaxial layer formed on the surface of the substrate; an electrode layer formed on the surface of the epitaxial layer and located at both ends of the surface of the epitaxial layer; and an insulating layer covering a first remaining portion of the surface of the epitaxial layer; wherein the insulating layer and the electrode layer form a plane, and the first remaining portion is the portion of the epitaxial layer not covered by the electrode layer; wherein the absorption layer covers the sidewalls of the epitaxial layer and the electrode layer, and covers a second remaining portion of the surface of the substrate; the absorption layer is higher than the plane formed by the insulating layer and the electrode layer, and the second remaining portion is the portion of the substrate not covered by the epitaxial layer.

[0011] In some embodiments of this disclosure, the epitaxial layer includes: a u-GaN buffer layer formed on the surface of the substrate; an N-GaN epitaxial layer covering the surface of the u-GaN buffer layer; a multiple quantum well (MQW) layer covering the surface of the N-GaN epitaxial layer, one end of the electrode layer being formed on the MQW layer; and a P-GaN layer formed on the surface of the MQW layer and extending from the surface edge of the MQW layer, the other end of the electrode layer being formed on the P-GaN layer; wherein the insulating layer covers the portion of the P-GaN layer not covered by the electrode layer, and the insulating layer covers the portion of the MQW layer not covered by the electrode layer and the P-GaN layer.

[0012] In some embodiments of this disclosure, the electrode layer includes: a P-electrode formed on the surface of the P-GaN layer and extending from the surface edge of the P-GaN layer, the electrode material being CrAlAu; and an N-electrode formed on the surface of the multiple quantum well (MQW) layer and extending from the surface edge of the MQW layer, the electrode material being CrAlAu; wherein the P-electrode, the N-electrode, and the insulating layer form a plane.

[0013] In some embodiments of this disclosure, the area of ​​the MicroLED pixel unit is less than 0.003 mm². 2 The absorption layer is made of a black polymer-based organic material with a thickness of 20-40 μm, including a black photosensitive cover film.

[0014] In some embodiments of this disclosure, the substrate is made of sapphire; the insulating layer is made of SiO2; and the epitaxial layer is made of a non-conductive material.

[0015] According to another aspect of this disclosure, a method for fabricating a MicroLED light-emitting array structure as described above is provided, comprising: step 1: fabricating a plurality of MicroLED pixel unit substrates on a substrate; step 2: fabricating absorption layers on both sides of each MicroLED pixel unit substrate to form a plurality of MicroLED pixel units; step 3: interconnecting the plurality of MicroLED pixel units with row lines and column lines to form the MicroLED light-emitting array structure.

[0016] In some embodiments of this disclosure, the method further includes: step 4: preparing a plurality of reflective layers at the bottom of the substrate 1, wherein the plurality of reflective layers are correspondingly disposed with respect to the plurality of MicroLED pixel unit substrates; wherein step 2 is prepared by vacuum hot pressing or coating method to prepare the absorption layer, and step 4 is prepared by vacuum hot pressing or coating method to prepare the reflective layer.

[0017] According to another aspect of this disclosure, a MicroLED display device is provided, including the MicroLED light-emitting array structure described above.

[0018] (III) Beneficial Effects

[0019] Based on the above technical solution, this disclosure has at least one or a portion of the following beneficial effects compared to the prior art:

[0020] 1. This disclosure improves contrast by preparing an absorption layer between MicroLED pixel units to absorb side light from the pixel units, and the process is simple and low cost.

[0021] 2. This disclosure improves the chip reflectivity by preparing a reflective layer on the back side of the substrate of the MicroLED pixel unit, and not preparing a reflective layer on the edge of each pixel unit, while solving the problems of high light intensity and uneven light output at the chip corners. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the MicroLED light-emitting array structure according to an embodiment of the present disclosure.

[0023] [Explanation of Labels in the Attached Image]

[0024] 1: Substrate

[0025] 2: u-GaN buffer layer

[0026] 3: N-GaN epitaxial layer

[0027] 4: Multi-quantum well MQW layer

[0028] 5: P-GaN layer

[0029] 6: P electrode

[0030] 7: N electrode

[0031] 8: Insulation layer

[0032] 9: Absorption layer

[0033] 10: Reflective layer

[0034] 11: MicroLED pixel unit

[0035] 12: Epitaxial layer

[0036] 13: Electrode layer Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0038] Certain embodiments of this disclosure will be described more fully below with reference to the accompanying drawings, some of which, but not all, will be shown. In fact, various embodiments of this disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable this disclosure to meet applicable legal requirements.

[0039] As one aspect of this disclosure, a MicroLED light-emitting array structure is provided. Figure 1 A schematic diagram of a MicroLED light-emitting array structure according to an embodiment of the present disclosure is shown.

[0040] like Figure 1 As shown, the MicroLED light-emitting array structure includes multiple MicroLED pixel units 11 arranged in an array structure with interconnected rows and columns, wherein the area of ​​each MicroLED pixel unit 11 is less than 0.003 mm². 2 .

[0041] like Figure 1 As shown, the MicroLED pixel unit 11 includes a substrate 1, a MicroLED pixel unit substrate, and an absorption layer 9.

[0042] Substrate 1 can be made of sapphire; the MicroLED pixel unit substrate is formed on substrate 1, providing a light source for the MicroLED pixel unit 11; such as Figure 1 As shown, the absorption layer 9 is formed on the substrate 1 and located on both sides of the MicroLED pixel unit substrate, and is higher than the surface of the MicroLED pixel unit substrate. The absorption layer 9 can absorb the side light of the MicroLED pixel unit 11 and prevent crosstalk between different colors of light.

[0043] According to the embodiments of this disclosure, the absorption layer 9 can be made of a black polymer-based organic material with a thickness of 20-40 μm, and the black polymer-based organic material can be a black photosensitive and developable cover film.

[0044] In some embodiments of this disclosure, the MicroLED pixel unit 11 further includes a reflective layer 10.

[0045] A reflective layer 10 is formed on the bottom of the substrate 1. It reflects visible light from the MicroLED pixel unit 11, improving reflectivity and solving the problems of high light intensity and uneven light emission at the corners. The reflective layer 10 is recessed by 2-8 μm from the bottom edge of the substrate 1. The reflective layer 10 can be made of a white polymer-based organic material with a thickness of 20-40 μm, and the white polymer-based organic material can be a white photosensitive and developable cover film.

[0046] In some embodiments of this disclosure, the MicroLED pixel unit substrate includes an epitaxial layer 12, an electrode layer 13, and an insulating layer 8.

[0047] The epitaxial layer 12 can be made of a non-conductive material and is formed on the surface of the substrate 1.

[0048] Electrode layer 13 is formed on the surface of epitaxial layer 12 and is located at both ends of the surface of epitaxial layer 12, such as... Figure 1 As shown, the electrode layer 13 is divided into two parts. One part extends from the left edge of the epitaxial layer 12 to the right, and the other part extends from the right edge of the epitaxial layer 12 to the left. The electrode layer 13 is suitable for interconnecting the row lines and column lines of multiple MicroLED pixel units 11 to form a MicroLED light-emitting array structure.

[0049] The insulating layer 8 can be made of SiO2. The insulating layer 8 covers the first remaining portion of the surface of the epitaxial layer 12, which is the portion of the epitaxial layer 12 not covered by the electrode layer 13. Figure 1 As shown, the insulating layer 8 covers the portion of the surface of the epitaxial layer 12 that is not covered by the electrode layer 13, and the insulating layer 8 and the electrode layer 13 form a plane.

[0050] In some embodiments of this disclosure, the absorber layer 9 covers the sidewalls of the epitaxial layer 12 and the electrode layer 13, and covers the portion of the substrate 1 surface not covered by the epitaxial layer 12. Furthermore, the upper surface of the absorber layer 9 is higher than the upper surfaces of the epitaxial layer 12 and the electrode layer 13. Figure 1 As shown.

[0051] In some embodiments of this disclosure, the epitaxial layer 12 includes: a u-GaN buffer layer 2, an N-GaN epitaxial layer 3, a multiple quantum well (MQW) layer 4, and a P-GaN layer 5.

[0052] u-GaN buffer layer 2 is formed on the surface of substrate 1; N-GaN epitaxial layer 3 covers the surface of u-GaN buffer layer 2; multi-quantum well (MQW) layer 4 covers the surface of N-GaN epitaxial layer 3; P-GaN layer 5 is formed on the surface of multi-quantum well (MQW) layer 4 and extends from the surface edge of multi-quantum well (MQW) layer 4, such as... Figure 1 As shown, the P-GaN layer 5 extends to the right from the left edge of the multi-quantum-well (MQW) layer 4; one end of the electrode layer 13 is formed on the MQW layer 4, and the other end of the electrode layer 13 is formed on the P-GaN layer 5, as shown. Figure 1 As shown, the electrode layer 13 is divided into two parts. One part extends from the right edge of the multi-quantum well (MQW) layer 4 to the left, and the other part extends from the left edge of the P-GaN layer 5 to the right.

[0053] In this configuration, insulating layer 8 covers the portion of P-GaN layer 5 not covered by electrode layer 13, and insulating layer 8 also covers the portion of multiple quantum well (MQW) layer 4 not covered by electrode layer 13 and P-GaN layer 5. Insulating layer 8 and electrode layer 13 form a plane. Figure 1 As shown.

[0054] In some embodiments of this disclosure, the electrode layer 13 includes a P electrode 6 and an N electrode 7.

[0055] P-electrode 6 is formed on the surface of P-GaN layer 5 and extends from the surface edge of P-GaN layer 5. The electrode material can be CrAlAu. For example... Figure 1 As shown, the P electrode 6 extends to the right from the left edge of the surface of the P-GaN layer 5.

[0056] The N-electrode 7 is formed on the surface of the multi-quantum-well (MQW) layer 4 and extends from the surface edge of the MQW layer 4. The electrode material can be CrAlAu. For example... Figure 1 As shown, the N electrode 7 extends from the right edge of the surface of the multi-quantum well (MQW) layer 4 to the left.

[0057] The upper surfaces of the P electrode 6, N electrode 7, and insulating layer 8 form a plane. The P electrode 6 and N electrode 7 are used to interconnect the row and column lines of multiple MicroLED pixel units 11 to form a MicroLED light-emitting array structure.

[0058] As another aspect of this disclosure, a method for fabricating a MicroLED light-emitting array structure is also provided, specifically including the following steps:

[0059] Step 1: Take a substrate 1 and sequentially grow a u-GaN buffer layer 2, an N-GaN epitaxial layer 3, a multiple quantum well (MQW) layer 4 and a P-GaN layer 5 in an MOCVD device to form an epitaxial layer 12;

[0060] Step 2: Perform ICP mesa etching on epitaxial layer 12, etching part of epitaxial layer 12 up to the surface of multi-quantum well (MQW) layer 4;

[0061] Step 3: Perform ICP deep etching on the pixel edges of the epitaxial layer 12, etching down to the bottom of the substrate 1 to form multiple MicroLED pixel unit substrates;

[0062] Step 4: Fabricate N electrode 7 on the multi-quantum well (MQW) layer 4 on the multiple MicroLED pixel unit substrates, and fabricate P electrode 6 on the P-GaN layer 5 on the multiple MicroLED pixel unit substrates;

[0063] Step 5: Cover the portion of the multiple MicroLED pixel unit substrate that is not covered by the P electrode 6 and N electrode 7 with an insulating layer 8;

[0064] Step 6: Prepare an absorption layer 9 between multiple MicroLED pixel unit substrates;

[0065] Step 7: A plurality of reflective layers 10 are prepared on the bottom of the substrate 1, and the plurality of reflective layers 10 are disposed in a one-to-one correspondence with the plurality of MicroLED pixel unit substrates to form a plurality of MicroLED pixel units 11;

[0066] Step 8: Interconnect the row lines and column lines of multiple MicroLED pixel units 11 to form a MicroLED light-emitting array structure.

[0067] According to an embodiment of this disclosure, in step 2, the absorbent layer 9 can be prepared by vacuum hot pressing or coating.

[0068] According to an embodiment of this disclosure, in step 4, the reflective layer 10 can be prepared by a vacuum hot pressing method or a coating method.

[0069] As another aspect of this disclosure, a MicroLED display device is also provided, specifically including the MicroLED light-emitting array structure as described above, wherein the MicroLED light-emitting array structure can be prepared using the preparation method described above.

[0070] The embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and have not been described in detail.

[0071] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0072] Furthermore, the shapes and dimensions of the components in the figures do not reflect actual size and proportion, but are merely illustrative of embodiments of this disclosure. Additionally, any reference signs placed between parentheses in the claims should not be construed as limiting the scope of the claims.

[0073] Unless otherwise stated, the numerical parameters in this specification and the appended claims are approximate values ​​and can be varied according to desired characteristics derived from the content of this disclosure. Specifically, all figures used in the specification and claims to indicate composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. Generally, this means that a specific amount varies by ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments.

[0074] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0075] The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify the corresponding elements does not imply that the element has any ordinal number, nor does it represent the order of one element with another element, or the order of manufacturing methods. The use of these ordinal numbers is only to enable a clear distinction between an element with a certain name and another element with the same name.

[0076] Furthermore, unless specifically described or required to occur in a specific order, the order of the above steps is not limited to those listed above and can be varied or rearranged according to the desired design. Moreover, the above embodiments can be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments.

[0077] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose. Furthermore, in the unit claims enumerating several means, several of these means may be embodied by the same hardware item.

[0078] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the disclosure, in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. However, this approach to disclosure should not be construed as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the aspects of the disclosure consist of fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the disclosure.

[0079] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of this disclosure. It should be understood that the above are only specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A MicroLED light-emitting array structure, comprising: Multiple MicroLED pixel units (11) are arranged in an array structure with interconnected rows and columns; The MicroLED pixel unit (11) includes: Substrate (1); MicroLED pixel unit substrate, formed on the substrate (1); and An absorption layer (9) is formed on the substrate (1), located on both sides of the MicroLED pixel unit substrate, and above the surface of the MicroLED pixel unit substrate; A reflective layer (10) is formed at the bottom of the substrate (1). The reflective layer (10) is recessed by 2-8 μm relative to the bottom edge of the substrate (1) to reflect visible light from the MicroLED pixel unit (11) so that the light emission of the MicroLED pixel unit (11) is uniform.

2. The MicroLED light-emitting array structure according to claim 1, wherein, The reflective layer (10) is made of a white polymeric organic material with a thickness of 20-40 μm, and the white polymeric organic material includes a white photosensitive cover film.

3. The MicroLED light-emitting array structure according to claim 1, wherein, The MicroLED pixel unit substrate includes: An epitaxial layer (12) is formed on the surface of the substrate (1); An electrode layer (13) is formed on the surface of the epitaxial layer (12) and located at both ends of the surface of the epitaxial layer (12); and An insulating layer (8) covers a first remaining portion of the surface of the epitaxial layer (12); wherein the insulating layer (8) and the electrode layer (13) form a plane, and the first remaining portion is the portion of the epitaxial layer (12) not covered by the electrode layer (13); The absorption layer (9) covers the sidewalls of the epitaxial layer (12) and the electrode layer (13), and covers the second remaining portion of the surface of the substrate (1); the absorption layer (9) is higher than the plane formed by the insulating layer (8) and the electrode layer (13), and the second remaining portion is the part of the substrate (1) not covered by the epitaxial layer (12).

4. The MicroLED light-emitting array structure according to claim 3, wherein, The epitaxial layer (12) includes: A u-GaN buffer layer (2) is formed on the surface of the substrate (1); An N-GaN epitaxial layer (3) covers the surface of the u-GaN buffer layer (2); A multi-quantum well (MQW) layer (4) covers the surface of the N-GaN epitaxial layer (3), and one end of the electrode layer (13) is formed on the multi-quantum well (MQW) layer (4); and A P-GaN layer (5) is formed on the surface of the multi-quantum well (MQW) layer (4) and extends from the surface edge of the multi-quantum well (MQW) layer (4), and the other end of the electrode layer (13) is formed on the P-GaN layer (5); The insulating layer (8) covers the portion of the P-GaN layer (5) not covered by the electrode layer (13), and the insulating layer (8) covers the portion of the multiple quantum well (MQW) layer (4) not covered by the electrode layer (13) and the P-GaN layer (5).

5. The MicroLED light-emitting array structure according to claim 4, wherein, The electrode layer (13) includes: A P-electrode (6) is formed on the surface of the P-GaN layer (5) and extends from the surface edge of the P-GaN layer (5), the electrode material being CrAlAu; and The N electrode (7) is formed on the surface of the multi-quantum well (MQW) layer (4) and extends from the surface edge of the multi-quantum well (MQW) layer (4), and the electrode material is CrAlAu; The P electrode (6), the N electrode (7), and the insulating layer (8) form a plane.

6. The MicroLED light-emitting array structure according to any one of claims 1 to 5, wherein: The area of ​​the MicroLED pixel unit (11) is less than 0.003 mm². 2 ; The absorption layer (9) is made of a black polymer organic material with a thickness of 20-40 μm, including a black photosensitive cover film.

7. The MicroLED light-emitting array structure according to any one of claims 3 to 5, wherein: The substrate (1) is made of sapphire. The insulating layer (8) is made of SiO2 material; The material of the epitaxial layer (12) is a non-conductive material.

8. A method for fabricating a MicroLED light-emitting array structure as described in any one of claims 1 to 7, comprising: Step 1: Fabricate multiple MicroLED pixel unit substrates on substrate (1); Step 2: Prepare absorption layers (9) on both sides of each MicroLED pixel unit substrate to form multiple MicroLED pixel units (11). Step 3: Interconnect the row lines and column lines of the multiple MicroLED pixel units (11) to form the MicroLED light-emitting array structure; Step 4: A plurality of reflective layers (10) are prepared at the bottom of the substrate 1. The plurality of reflective layers (10) are disposed corresponding to the plurality of MicroLED pixel unit substrates. The reflective layers (10) are recessed by 2-8 μm relative to the bottom edge of the substrate (1) to reflect visible light from the MicroLED pixel unit (11) so that the light emission of the MicroLED pixel unit (11) is uniform.

9. The preparation method according to claim 8, wherein, Step 2 uses a vacuum hot pressing method or a coating method to prepare the absorption layer (9), and step 4 uses a vacuum hot pressing method or a coating method to prepare the reflective layer (10).

10. A MicroLED display device, comprising a MicroLED light-emitting array structure as described in any one of claims 1 to 7.

Images