Stacked-structure Micro-LED display module capable of preventing optical crosstalk and preparation method of stacked-structure Micro-LED display module

Abstract

The invention discloses a stacked structure Micro-LED display module capable of preventing optical crosstalk and a preparation method of the stacked structure Micro-LED display module. Relates to the field of optical semiconductors, the display module comprises a plurality of pixel units arranged in an array mode, each pixel unit comprises a substrate layer and a passivation layer which are arranged in a stacked mode, a plurality of light-emitting blocks are arranged between the substrate layer and the passivation layer, and the light-emitting blocks are arranged in a stacked mode; an N electrode is arranged on each light-emitting block, the N electrodes are not communicated with one another, and the light-emitting blocks are jointly connected with a P electrode; the N electrode and the P electrode are isolated through a passivation layer; according to the method, the display module is prepared through layer-by-layer stacking and patterning; the electrodes of the multiple light-emitting blocks are arranged at intervals, under the control of forward and reverse voltages or currents, photon-generated carriers generated by the short-wavelength LED on the photoluminescence effect of the long-wavelength LED are made to reversely migrate, composite light emitting is not conducted on the light-emitting layer, light emitting of different wavelengths completely depends on electric control is achieved, and under the condition that bias voltage is applied for regulation and control, the light emitting efficiency is improved. The phenomenon of light crosstalk in the multi-color stacked Micro-LED chips is reduced, and the saturation degree of Micro-LED display is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a stacked structure Micro-LED display module for preventing light crosstalk and a preparation method thereof. Background Art

[0002] Light Emitting Diode (LED) is a solid-state light source with high brightness and high luminous efficiency. In recent years, Micro-LED production technology has attracted widespread attention in related fields. Compared with LCD and OLED, Micro-LED has great advantages in low power consumption, fast response and high light efficiency, and has great commercial value in technical fields such as high-resolution displays, virtual reality and augmented reality.

[0003] In the field of semiconductor technology, optical crosstalk of Micro-LED light-emitting pixels has a significant impact on display saturation. For example, in the existing three-color stacked display screens on the market, the blue light LED has photoluminescence on the green light LED and the red light LED, which in turn affects the purity of the pixel light emission.

[0004] In the prior art, optical crosstalk between pixels is usually restrained by reflection and blocking. The common method within a pixel is to reduce the brightness of short-wavelength light through reflection, thereby reducing its photoluminescence effect on long wavelengths and reducing the optical crosstalk phenomenon, but affecting the brightness of the pixel. In addition, it is difficult to restrain the optical crosstalk within the pixel by blocking. Therefore, it is urgent to provide a preparation scheme that can avoid optical crosstalk within micro-display luminous pixels. Summary of the invention

[0005] In order to reduce the influence of light crosstalk on the purity and brightness of pixel light emission, the present application provides a stacked structure Micro-LED display module with anti-light crosstalk and a preparation method thereof.

[0006] In a first aspect, the present application provides a stacked structure Micro-LED display module for preventing light crosstalk, which adopts the following technical solutions:

[0007] A stacked structure Micro-LED display module for preventing light crosstalk includes a plurality of pixel units arranged in an array, the pixel units include a substrate layer and a passivation layer arranged in a stacked manner, a plurality of light-emitting blocks are arranged between the substrate layer and the passivation layer, and the plurality of light-emitting blocks are arranged in a stacked manner; an N electrode is provided on each light-emitting block, the plurality of N electrodes are not connected to each other, and the plurality of light-emitting blocks are commonly connected to a P electrode; the N electrode and the P electrode are isolated from each other by the passivation layer.

[0008] Optionally, the light-emitting block includes a bonding layer and an epitaxial layer, and the epitaxial layer is stacked on the bonding layer; each epitaxial layer is provided with an N electrode, and multiple epitaxial layers are commonly connected to a P electrode, and the N electrodes can be controlled individually.

[0009] Optionally, the passivation layer is SiO2 and is wrapped around the surface of the pixel unit.

[0010] Optionally, the passivation layer is SiO2 and is wrapped around the surface of the pixel unit and between two adjacent light-emitting blocks.

[0011] Optionally, the P electrode and the N electrode are a single-layer structure or a multi-layer structure; the electrode material is one or more of ITO or a conductive two-dimensional material.

[0012] Optionally, the substrate layer is a pixel driving substrate layer.

[0013] Optionally, the material system of the epitaxial layer is one of AlGaInN, AlGaInP or AsGaInP based III-V group compounds.

[0014] Optionally, the epitaxial layer includes a reflective layer, a P-type current spreading layer, a P-type layer, a light-emitting layer, an N-type layer, an N-type ohmic contact layer and a transparent electrode layer stacked in sequence; the reflective layer is connected to the bonding layer, the transparent electrode layer is connected to the N-electrode, and the P-type current spreading layer is connected to the P-electrode.

[0015] In a second aspect, the present application also provides a method for manufacturing a stacked structure Micro-LED display module that prevents light crosstalk, using the following technical solution:

[0016] A method for manufacturing a stacked structure Micro-LED display module for preventing light crosstalk comprises the following steps:

[0017] S1, bonding the light-emitting block to the substrate;

[0018] S2, stacking a plurality of light-emitting blocks on the light-emitting block;

[0019] S3, patterning the entire stacked structure;

[0020] S4, depositing a passivation layer on the outer surface of the overall structure;

[0021] S5. Patterning the passivation layer and depositing electrodes.

[0022] In summary, this application includes the following beneficial technical effects:

[0023] The present application separates and sets multiple light-emitting blocks, and under the control of forward and reverse voltages or currents, causes the photogenerated carriers produced by the photoluminescence effect of short-wavelength LEDs on long-wavelength LEDs to migrate in the opposite direction, without recombining the light in the light-emitting layer, thereby achieving light emission of different wavelengths completely relying on electrical control. Under the condition of forward and reverse voltage regulation, the phenomenon of optical crosstalk in multi-color stacked Micro-LED chips is reduced, thereby improving the saturation of Micro-LED display. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an overall top view of the stacked structure Micro-LED display module for preventing light crosstalk in the present application;

[0025] Figure 2 yes Figure 1 A cross-sectional view of the overall structure of the embodiment 1 of the pixel unit;

[0026] Figure 3 yes Figure 2 A cross-sectional view of the overall structure of the epitaxial layer;

[0027] Figure 4 is a top view of the overall structure of Example 2;

[0028] Figure 5 is a cross-sectional view of the overall structure of the pixel unit embodiment 3;

[0029] Figure 6 is a cross-sectional view of the overall structure of a pixel unit embodiment 4;

[0030] Figure 7 This is a photoluminescence spectrum diagram of the long wavelength LED of Example 3 under reverse bias.

[0031] Description of reference numerals:

[0032] 1. Pixel unit; 11. Substrate layer; 12. Bonding layer; 13. Epitaxial layer; 14. Passivation layer; 15. N-electrode; 16. P-electrode; 131. Reflective layer; 132. P-type current spreading layer; 133. P-type layer; 134. Light-emitting layer; 135. N-type layer; 136. N-type ohmic contact layer; 137. Transparent electrode layer. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-7 This application is described in further detail.

[0034] Embodiment 1;

[0035] The present application embodiment discloses a stacked structure Micro-LED display module to prevent light crosstalk, such as Figure 1 and Figure 2As shown, the display screen includes a plurality of pixel units 1 arranged in an array, and the pixel unit 1 includes a stacked substrate layer 11 and a passivation layer 14, the substrate layer 11 is a pixel driving substrate layer 11, and the passivation layer 14 is SiO2; a plurality of stacked light-emitting blocks are arranged between the passivation layer 14 and the substrate layer 11, and the light-emitting blocks include a bonding layer 12 and an epitaxial layer 13, the epitaxial layer 13 is stacked on the bonding layer 12 to be connected to the substrate layer 11, and the bonding layer 12 in the bottom light-emitting block is connected to the substrate layer 11; in the present embodiment, there are three light-emitting blocks, namely, there are three bonding layers 12 and three epitaxial layers 13, and adjacent epitaxial layers 13 and bonding layers 12 are tightly stacked; the passivation layer 14 is wrapped around the surface of the pixel unit 1.

[0036] like Figure 3 As shown, the material system of the epitaxial layer 13 is one of the III-V compounds based on AlGaInN, AlGaInP or AsGaInP; it includes a reflective layer 131, a P-type current spreading layer 132, a P-type layer 133, a light-emitting layer 134, an N-type layer 135, an N-type ohmic contact layer and a transparent electrode layer 137 stacked in sequence from bottom to top; the reflective layer 131 is connected to the bonding layer 12, the transparent electrode layer 137 is connected to the N-electrode 15 with one end extending out of the surface of the passivation layer 14, and the P-type current spreading layer 132 is connected to the P-electrode 16 with one end extending out of the surface of the passivation layer 14; the P-electrode 16 and the N-electrode 15 are single-layer structures; the electrode material is ITO; the N-electrodes 15 of the three epitaxial layers 13 are not connected, and the three epitaxial layers 13 share the same P-electrode 16 ; The N electrode 15 is isolated from the P electrode 16 by the passivation layer 14; therefore, a single light-emitting block can be electrically controlled separately; in order to reduce optical crosstalk during operation, the P electrode is grounded, and when a positive bias is applied to the N electrode of the top blue light LED, a negative bias is applied to the N electrode of the middle green light LED, and a negative bias is applied to the N electrode of the bottom red light LED or no power is applied; when a positive bias is applied to the N electrode of the middle green light LED, the top blue light LED is not powered, and a negative bias is applied to the N electrode of the bottom red light LED; by applying a reverse bias to the long-wavelength LED, electrical unblocking is achieved, the carriers generated by the short-wavelength LED exciting the long-wavelength LED in the Micro-LED light-emitting layer are reduced, the photoluminescence effect of the short-wavelength LED on the long-wavelength LED is reduced, and crosstalk of light of different wavelengths is prevented.

[0037] It should be noted that the pixel unit 1 may be circular or square. In the embodiment of the present application, the pixel unit 1 is square.

[0038] Embodiment 2;

[0039] like Figure 4As shown, in the embodiment of the present application, the pixel unit 1 is circular; the P electrode 16 and the N electrode 15 have a mutual angle and are distributed around the pixel, and the N electrode 15 is three small-angle concentric rings, which can also be controlled separately.

[0040] Embodiment 3,;

[0041] like Figure 5 As shown, the difference between the embodiment of the present application and embodiment 1 is that the number of light-emitting blocks is different. In the embodiment of the present application, the number of light-emitting blocks is two, which is a dual-color Micro-LED; in order to reduce optical crosstalk during operation, the P electrode is grounded, and when a positive bias is applied to the N electrode of the top short-wavelength LED, a negative bias is applied to the N electrode of the bottom long-wavelength LED; it is used in some fields that only require dual-color Micro-LEDs, and at the same time, the complexity of the chip process can be reduced.

[0042] like Figure 7 As shown, in the implementation of the present application, a negative bias is applied to the long-wavelength LED, and its photoluminescence is weakened, and as the negative bias increases, the weakening effect becomes more obvious. This is because the photogenerated carriers in the long-wavelength LED excited by the short-wavelength LED light move in the opposite direction under the action of the electric field, that is, the holes migrate to the P-type layer 133, and the electrons migrate to the N-type layer 135, and the electron holes do not recombine and emit light in the light-emitting layer 134. In this way, when the short-wavelength LED emits light, the long-wavelength LED is not affected by the photoluminescence, reducing the light crosstalk within the pixel.

[0043] Embodiment 4;

[0044] like Figure 6 As shown, the embodiment of the present application is different from Embodiment 1 in that: the setting of the passivation layer 14 is different. In the embodiment of the present application, the passivation layer 14 not only exists on the surface of the pixel unit 1, but also exists between the adjacent light-emitting blocks; the three epitaxial layers 13 are isolated and filled in the entire Micro-LED as supporting materials; multiple epitaxial layers 13 are connected by the P electrode 16, and at the same time, the passivation layer 14 also realizes the function of partially supporting the epitaxial layer 13.

[0045] The present application also discloses a method for manufacturing a stacked structure Micro-LED display module with light crosstalk prevention, which is applicable to the display screens shown in Examples 1, 2, and 3; the method comprises the following steps:

[0046] S1, bonding the light-emitting block to the substrate;

[0047] S2, stacking a plurality of light-emitting blocks on the light-emitting block;

[0048] S3, patterning the entire stacked structure;

[0049] S4, depositing a passivation layer 14 on the outer surface of the overall structure;

[0050] S5, patterning the passivation layer 14 and depositing electrodes; the patterning of the passivation layer 14 can be complementary to the electrode pattern, and the electrodes can be prepared by spin coating or deposition.

[0051] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A stacked structure Micro-LED display module for preventing light crosstalk, characterized in that: The invention comprises a plurality of pixel point units (1) arranged in an array, wherein the pixel point unit (1) comprises a substrate layer (11) and a passivation layer (14) arranged in a stacked manner, wherein a plurality of light-emitting blocks are arranged between the substrate layer (11) and the passivation layer (14), and the plurality of light-emitting blocks are arranged in a stacked manner; an N electrode (15) is arranged on each light-emitting block, the plurality of N electrodes (15) are not interconnected, and the plurality of light-emitting blocks are connected to a P electrode (16) in common; and the N electrode (15) and the P electrode (16) are isolated from each other by the passivation layer (14).

2. The stacked structure Micro-LED display module with light crosstalk prevention according to claim 1, characterized in that: The light-emitting block comprises a bonding layer (12) and an epitaxial layer (13), wherein the epitaxial layer (13) is stacked on the bonding layer (12); an N electrode (15) is provided on each epitaxial layer (13), a plurality of epitaxial layers (13) are commonly connected to a P electrode (16), and the N electrodes (15) can be individually controlled.

3. The stacked structure Micro-LED display module with light crosstalk prevention according to claim 2, characterized in that: The passivation layer (14) is SiO2 and is wrapped around the surface of the pixel unit (1).

4. The stacked structure Micro-LED display module with light crosstalk prevention according to claim 2, characterized in that: The passivation layer (14) is SiO2 and wraps around the surface of the pixel unit (1) and between two adjacent light-emitting blocks.

5. The stacked structure Micro-LED display module with light crosstalk prevention according to claim 1, characterized in that: The P electrode (16) and the N electrode (15) are single-layer structures or multi-layer structures; the electrode material is one or more of ITO or conductive two-dimensional materials.

6. The stacked structure Micro-LED display module with light crosstalk prevention according to claim 1, characterized in that: The substrate layer (11) is a pixel driving substrate layer (11).

7. The stacked structure Micro-LED display module with light crosstalk prevention according to claim 2, characterized in that: The material system of the epitaxial layer (13) is one of AlGaInN, AlGaInP or AsGaInP based III-V group compounds.

8. The stacked structure Micro-LED display module with light crosstalk prevention according to claim 2, characterized in that: The epitaxial layer (13) comprises a reflective layer (131), a P-type current spreading layer (132), a P-type layer (133), a light-emitting layer (134), an N-type layer (135), an N-type ohmic contact layer and a transparent electrode layer (137) which are stacked in sequence; the reflective layer (131) is connected to the bonding layer (12), the transparent electrode layer (137) is connected to the N-electrode (15), and the P-type current spreading layer (132) is connected to the P-electrode (16).

9. A method for manufacturing a stacked structure Micro-LED display module with light crosstalk protection, which is used to prepare a stacked structure Micro-LED display module with light crosstalk protection as claimed in claim 3, characterized in that The steps include: S1, bonding the light-emitting block to the substrate; S2, stacking a plurality of light-emitting blocks on the light-emitting block; S3, patterning the entire stacked structure; S4, depositing a passivation layer (14) on the outer surface of the overall structure; S5, patterning the passivation layer (14) and depositing electrodes.

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