Micro light-emitting diode array device and preparation method therefor

Abstract

A micro light-emitting diode array device and a preparation method therefor. The device comprises a driving circuit layer and a dielectric layer disposed above the driving circuit layer; a plurality of columns of light-emitting array strips are provided in the dielectric layer, and each column of light-emitting array strip comprises a P-type electrode layer and a plurality of light-emitting units arranged on the P-type electrode layer one by one; each light-emitting unit comprises a light-emitting layer and an N-type electrode layer disposed above the light-emitting layer; the N-type electrode layer is connected to the driving circuit layer by means of an N-type through hole, and the P-type electrode layer is connected to the driving circuit layer by means of a P-type through hole. The technical problems in the prior art of high preparation technology difficulty and costs, being not suitable to use a semiconductor process method, and being difficult to achieve mass production of devices are solved.

Description

Micro light emitting diode array device and preparation method thereof Technical Field

[0001] The present disclosure relates to the technical field of LED chips, and in particular to a micro light emitting diode array device and a preparation method thereof. Background Art

[0002] Micro light emitting diode (LED) arrays have the advantages of high color saturation, high contrast, fast response, low energy consumption and long service life.

[0003] Currently, micro-LED arrays have two structures: vertical and flip-chip. However, vertical LED arrays require light output through the bottom or side, which limits the selectivity of the light emission direction. In addition, since light needs to be transmitted through the material interfaces between multiple layers in the vertical structure, light loss and reflection increase, thereby reducing light extraction efficiency. At the same time, the preparation process of the vertical structure is relatively complex, requiring multiple deposition and processing steps between different layers, which increases the technical difficulty and cost of preparation. In the flip-chip structure, the LED chip is flip-chip mounted on a heat dissipation substrate, which makes thermal management difficult. The lack of direct contact between the optoelectronic chip and the heat dissipation substrate limits heat conduction and heat dissipation efficiency, which can easily lead to chip overheating and performance degradation. At the same time, the electrical connection in the flip-chip structure needs to be made through gold wires or micro solder joints, which increases the complexity of the manufacturing process and increases the fragility and reliability of the electrical connection. In addition, the light output in the flip-chip structure is mainly carried out at the bottom of the chip, and the light output direction is limited, making it difficult to achieve multi-directional light output.

[0004] Therefore, there is an urgent need for a micro light emitting diode array device that can reduce the technical difficulty and cost of preparation and is more suitable for mass production of devices using semiconductor process methods. Summary of the Invention

[0005] The present disclosure provides a micro light emitting diode array device and a preparation method thereof to solve the technical problems in the prior art of high technical difficulty and cost, unsuitability for semiconductor process methods, and difficulty in achieving mass production of devices.

[0006] In order to solve the above technical problems, the embodiments of the present disclosure provide a micro light emitting diode array device, comprising: a driving circuit layer and a dielectric layer disposed above the driving circuit layer;

[0007] A plurality of columns of light-emitting array strips are provided in the dielectric layer, each column of the light-emitting array strips comprising a P-type electrode layer and a plurality of light-emitting units arranged one by one on the P-type electrode layer; each of the light-emitting units comprises a light-emitting layer and an N-type electrode layer provided above the light-emitting layer;

[0008] The N-type electrode layer is connected to the driving circuit layer through an N-type through-hole, and the P-type electrode layer is connected to the driving circuit layer through a P-type through-hole.

[0009] As a preferred solution, the light emitting array strips are evenly distributed in the dielectric layer.

[0010] As a preferred solution, the P-type electrode layer and the light-emitting layer on the P-type electrode layer are both arranged inside the dielectric layer, and the N-type electrode layer is arranged outside the dielectric layer.

[0011] As a preferred solution, there is a gap between the P-type electrode layer and the driving circuit layer, and the gap is filled with the dielectric layer.

[0012] As a preferred solution, the N-type electrode layer is connected to an N-contact pad provided in the driving circuit layer through the N-type through-holes; each of the N-type through-holes is connected to a corresponding N-contact pad.

[0013] As a preferred solution, the P-type electrode layer is connected to the P contact pad provided in the driving circuit layer through the P-type through-hole; each of the P-type through-holes is connected to a corresponding P contact pad, and each light-emitting array strip is only provided with one corresponding P-type through-hole and its connected P contact pad.

[0014] As a preferred solution, the N-type electrode layer is a transparent electrode.

[0015] As a preferred solution, the P-type electrode layer includes any one or more of ITO, nickel, gold, indium and copper.

[0016] As a preferred solution, the light-emitting units in the same column of the light-emitting array strips are arranged at equal intervals.

[0017] As a preferred solution, the projection size of each column of the light emitting array strips on the driving circuit layer is the same.

[0018] As a preferred solution, the light-emitting units in the same column of the light-emitting array strips have the same projection size on the driving circuit layer.

[0019] As a preferred solution, the P-type electrode layer and the driving circuit layer in different columns of the light emitting array strips have the same vertical distance.

[0020] As a preferred solution, in the arrangement direction of the light-emitting array strips of several columns, the P-type electrode layer and the light-emitting units thereon have the same width.

[0021] As a preferred solution, the N-type electrode layers in the same column of the light-emitting array strips are arranged at equal intervals.

[0022] As a preferred solution, in the arrangement direction of the light-emitting array strips in the columns, any two adjacent N-type electrode layers have the same spacing.

[0023] Accordingly, the present disclosure further provides a method for preparing a micro-LED array device, which is used to prepare the micro-LED array device as described in any one of the above items, comprising:

[0024] A gallium nitride substrate, a dielectric layer, an N-type gallium nitride, a multi-layer quantum well, and a P-type gallium nitride are sequentially grown on a silicon substrate to obtain a light-emitting diode epitaxial wafer; wherein the multi-layer quantum well is a light-emitting layer;

[0025] A light emitting array is fabricated on the light emitting diode epitaxial wafer, and a silicon-based CMOS wafer is used as a driving circuit; wherein the silicon-based CMOS wafer is provided with a P-type contact pad and an N-type contact pad, and the light emitting array includes a plurality of columns of light emitting array strips;

[0026] In the light emitting array, the common anode and each cathode of the light emitting array strips in the same row are independently connected to the driving circuit through corresponding through holes until all the light emitting array strips in all rows are connected to the driving circuit;

[0027] Connecting the light-emitting diode epitaxial wafer to the driving circuit by hybrid bonding, thereby achieving the combination of the common anode P-type through hole and the P contact pad of the driving circuit;

[0028] After wafer bonding, N-type through-hole metal of each cathode is made to connect with the driving circuit, and an N-type electrode layer is made;

[0029] The dielectric layer is filled to complete the preparation of the micro light emitting diode array device.

[0030] Compared with the prior art, the embodiments of the present disclosure have the following beneficial effects:

[0031] The technical solution disclosed herein adopts a micro-light-emitting diode array device structure. By arranging multiple columns of light-emitting array strips in a dielectric layer, each column includes multiple light-emitting units, so that the device can integrate a large number of light-emitting units in a smaller space, thereby achieving high integration and miniaturization, and is suitable for application scenarios requiring high-density light emission. At the same time, each light-emitting array strip adopts a light-emitting unit structure arranged one by one, and adjacent units are isolated by a dielectric layer. The entire column of light-emitting units can be prepared at one time, thereby improving production efficiency. In addition, by connecting with the through-holes of the driving circuit layer, the assembly process of the device can also be simplified, further improving production efficiency, reducing the technical difficulty and cost of preparation, and being suitable for mass production of devices using semiconductor process methods.

[0032] Furthermore, each light-emitting unit is composed of an independent light-emitting layer and an N-type electrode layer, and is connected to the driving circuit layer through an N-type through-hole, so that each light-emitting unit can be independently controlled to achieve precise adjustment of the current and light emission of each unit, providing flexibility. At the same time, the N-type through-hole and the P-type through-hole achieve an improvement in the current injection efficiency, avoid current loss and leakage, and improve the brightness and efficiency of the light-emitting unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a front cross-sectional view and a side cross-sectional view of a micro-LED array device provided in an embodiment of the present disclosure;

[0034] FIG2 is a front cross-sectional view and a side cross-sectional view of a through hole in a micro-LED array device provided by an embodiment of the present disclosure;

[0035] FIG3 is a flowchart of the steps of a method for preparing a micro-light emitting diode array device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present disclosure in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0037] Example 1

[0038] Please refer to FIG. 1 , which shows a micro light emitting diode array device provided in an embodiment of the present disclosure, including: a driving circuit layer and a dielectric layer disposed above the driving circuit layer.

[0039] In this embodiment, referring to FIG. 2 , the driving circuit layer in the LED chip controls the current and voltage of the LED chip, ensures its normal operation and stability, provides reverse current protection, and has functions such as brightness adjustment and dimming control.

[0040] It should be noted that the dielectric layer serves as an electrical and optical isolation layer, and is used to achieve electrical isolation between micro-LED arrays and between electrodes, and also to achieve optical and electrical isolation between light-emitting layers.

[0041] Several columns of light-emitting array strips are arranged in the dielectric layer, each column of the light-emitting array strips includes a P-type electrode layer and several light-emitting units arranged one by one on the P-type electrode layer; each light-emitting unit includes a light-emitting layer and an N-type electrode layer arranged above the light-emitting layer.

[0042] As a preferred solution of this embodiment, the light-emitting array strips are evenly distributed in the dielectric layer.

[0043] As a preferred solution of this embodiment, the P-type electrode layer and the light-emitting layer on the P-type electrode layer are both arranged inside the dielectric layer, and the N-type electrode layer is arranged outside the dielectric layer.

[0044] As a preferred solution of this embodiment, there is a gap between the P-type electrode layer and the driving circuit layer, and the gap is filled with the dielectric layer.

[0045] In this embodiment, the light-emitting array strips are evenly distributed within the dielectric layer, achieving more uniform light output and improving the brightness uniformity of the LED device, resulting in a more balanced and consistent light output. Each row of light-emitting array strips is composed of multiple light-emitting units arranged one behind the other, each including a light-emitting layer and an N-type electrode layer. This highly integrated design allows for a greater number of light-emitting units, improving the brightness output of the LED device.

[0046] Furthermore, the P-type electrode layer and light-emitting layer are disposed within the dielectric layer, while the N-type electrode layer is disposed outside the dielectric layer. This achieves electrical isolation, prevents short circuits within the device, and improves device stability and reliability. Furthermore, a gap exists between the P-type electrode layer and the driver circuit layer, which is filled with the dielectric layer. This simplifies the manufacturing process, reduces the number of steps and material usage, and lowers manufacturing costs.

[0047] In this embodiment, the light-emitting unit is designed so that the light-emitting layer is located above the N-type electrode layer. This design can effectively improve the light transmission efficiency and transmittance performance, and by optimizing the optical performance, the brightness and light output effect of the LED device can be improved.

[0048] In this embodiment, the thickness parameters between the layers are specific process parameters and can be adjusted according to the size and requirements of different LED array devices.

[0049] The N-type electrode layer is connected to the driving circuit layer through an N-type through-hole, and the P-type electrode layer is connected to the driving circuit layer through a P-type through-hole.

[0050] As a preferred solution of this embodiment, the N-type electrode layer is connected to the N-contact pad provided in the driving circuit layer through the N-type through-hole; each of the N-type through-holes is connected to a corresponding N-contact pad.

[0051] As a preferred solution of this embodiment, the P-type electrode layer is connected to the P contact pad provided in the driving circuit layer through the P-type through-hole; each of the P-type through-holes is connected to a corresponding P contact pad, and each light-emitting array strip is only provided with one corresponding P-type through-hole and its connected P contact pad.

[0052] In this embodiment, the N-type electrode is a transparent electrode made of indium tin oxide (ITO); the P-type electrode can be made of metal electrode materials such as ITO, nickel, gold, indium, and copper.

[0053] In this embodiment, different electrodes are connected to corresponding contact pads through their corresponding different through holes, thereby connecting the P-type electrode layer and / or the N-type electrode layer to the driving circuit layer, ensuring that the driving circuit layer can control the P-type electrode layer and / or the N-type electrode layer, thereby realizing functions such as brightness adjustment and dimming control of the light-emitting layer.

[0054] It is understood that the micro-LED array device in this embodiment employs a compact structural design, tightly integrating the driver circuit layer with the dielectric layer and the light-emitting array strip. This allows for lightweight and miniaturized devices, making them suitable for a variety of miniaturized applications. Furthermore, the light-emitting array strip is composed of several columns of light-emitting units, each of which includes a P-type electrode layer and an N-type electrode layer. By arranging the light-emitting units one by one, a high level of integration of multiple light-emitting units can be achieved within a limited space, improving the device's luminous density and functionality.

[0055] By connecting the N-type electrode layer and the P-type electrode layer to the driving circuit layer through N-type through-holes and P-type through-holes, effective current transmission can be achieved, ensuring that the current can accurately flow into the light-emitting unit, thereby improving the current injection efficiency and stability of the device. Each light-emitting unit includes a light-emitting layer and an N-type electrode layer arranged above it, so that efficient light transmission and low light loss can be achieved. At the same time, the provision of the dielectric layer can provide optical isolation, prevent light reflection and transmission, and improve the light output efficiency and brightness of the device. The preparation of the driving circuit layer, the dielectric layer, and the light-emitting array strip is relatively independent, and can be prepared using different process parameters and material selections. This flexibility can be optimized according to specific needs and can improve the performance and adaptability of the device.

[0056] The implementation of the above embodiment has the following effects:

[0057] The technical solution disclosed herein adopts a micro-LED array device structure. By arranging multiple columns of light-emitting array strips in a dielectric layer, each column includes multiple light-emitting units, so that the device can integrate a large number of light-emitting units in a smaller space, thereby achieving high integration and miniaturization, and is suitable for application scenarios requiring high-density light emission. At the same time, each light-emitting array strip adopts a light-emitting unit structure arranged one by one, and adjacent units are isolated by a dielectric layer. The entire column of light-emitting units can be prepared at one time, thereby improving production efficiency. Moreover, by connecting with the through-holes of the driving circuit layer, the assembly process of the device can also be simplified, further improving production efficiency, reducing the technical difficulty and cost of preparation, and being suitable for mass production of the device using semiconductor process methods.

[0058] Example 2

[0059] Please refer to FIG3 , which shows a method for preparing a micro-LED array device according to the present disclosure, and is used to prepare the micro-LED array device as described in the first embodiment, including the following steps S101-S106:

[0060] S101: Growing a gallium nitride base, a dielectric layer, an N-type gallium nitride, a multi-layer quantum well, and a P-type gallium nitride in sequence on a silicon substrate to obtain a light-emitting diode epitaxial wafer; wherein the multi-layer quantum well is a light-emitting layer.

[0061] In this embodiment, a three-dimensional through-hole connection method is used to connect the light-emitting diode array to the driving circuit. A light-emitting diode epitaxial wafer is obtained by sequentially growing a gallium nitride base, a buffer layer, an N-type gallium nitride, a multi-layer quantum well, and a P-type gallium nitride on a silicon substrate, and a light-emitting array is manufactured on the epitaxial wafer.

[0062] S102: manufacturing a light emitting array on the light emitting diode epitaxial wafer, and using a silicon-based CMOS wafer as a driving circuit; wherein a P-type contact pad and an N-type contact pad are provided on the silicon-based CMOS wafer, and the light emitting array includes a plurality of columns of light emitting array strips.

[0063] In this embodiment, a silicon-based CMOS wafer is used as the driving circuit, and P-type and N-type contact pads are manufactured on the wafer.

[0064] S103: In the light emitting array, the common anode and each cathode of the light emitting array strip in the same row are independently connected to the driving circuit through corresponding through holes until all the light emitting array strips in all rows are connected to the driving circuit.

[0065] In this embodiment, the common anode (P) and cathodes (N) of the units in the same row of the light emitting diode unit array are independently connected to the driving circuit through corresponding through holes.

[0066] S104: Connecting the light emitting diode epitaxial wafer to the driving circuit through hybrid bonding, thereby achieving the combination of the common anode P-type through hole and the P contact pad of the driving circuit.

[0067] In this embodiment, the light emitting diode wafer and the driving circuit wafer are combined by hybrid bonding, and the common anode P-type through-hole and the driving circuit P contact pad are combined at the same time.

[0068] S105: After wafer bonding, N-type through-hole metal of each cathode is made to connect with the driving circuit, and an N-type electrode layer is made.

[0069] In this embodiment, after wafer bonding, an N-type through-hole metal is fabricated to connect with the driving circuit, and an N-type transparent electrode is fabricated.

[0070] S106: Filling the dielectric layer, thereby completing the preparation of the micro light emitting diode array device.

[0071] In this embodiment, the dielectric layer serves as an electrical and optical isolation layer, and is used to achieve electrical isolation between micro-LED arrays and between electrodes, and also to achieve optical and electrical isolation between light-emitting layers.

[0072] It is understood that this embodiment uses a silicon substrate to grow a gallium nitride base, a buffer layer, an N-type gallium nitride, a multi-layer quantum well, and a P-type gallium nitride, and then fabricates a light-emitting array, which can achieve a high-quality light-emitting diode structure and improve the performance and efficiency of the device. At the same time, a silicon-based CMOS wafer is used as the substrate for the driver circuit to fabricate P-type and N-type contact pads. This method can integrate the driver circuit and the light-emitting diode on the same wafer, simplifying the manufacturing process and reducing manufacturing costs. The units in the same row of the light-emitting diode unit array share a common anode (P-type), and each cathode (N-type) is independently connected to the driver circuit through a through hole, which can reduce the complexity of the device, save space, and improve manufacturing efficiency. At the same time, the light-emitting diode wafer is combined with the driver circuit wafer through a hybrid bonding method to realize the combination of the common anode P-type through hole and the driver circuit N contact pad, and reliable device connection and good current transmission can be achieved, thereby improving the reliability and performance of the device. After the wafers are bonded, the N-type through hole metal is fabricated to connect to the driver circuit, and the N-type transparent electrode is fabricated, which can achieve good current distribution and light transmission, and improve the efficiency and brightness of the device. Finally, the dielectric layer is used as an electrical isolation and optical isolation layer to prevent mutual interference between current and light, thereby improving the performance and reliability of the device.

[0073] The implementation of the above embodiment has the following effects:

[0074] The technical solution disclosed herein adopts a micro-light-emitting diode array device structure. By arranging multiple columns of light-emitting array strips in a dielectric layer, each column includes multiple light-emitting units, so that the device can integrate a large number of light-emitting units in a smaller space, thereby achieving high integration and miniaturization, and is suitable for application scenarios requiring high-density light emission. At the same time, each light-emitting array strip adopts a light-emitting unit structure arranged one by one, and adjacent units are isolated by a dielectric layer. The entire column of light-emitting units can be prepared at one time, thereby improving production efficiency. In addition, by connecting with the through-holes of the driving circuit layer, the assembly process of the device can also be simplified, further improving production efficiency, reducing the technical difficulty and cost of preparation, and being suitable for mass production of devices using semiconductor process methods.

[0075] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the present disclosure. It should be understood that the above descriptions are merely specific embodiments of the present disclosure and are not intended to limit the scope of protection of the present disclosure. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure by those skilled in the art should be included within the scope of protection of the present disclosure.

Claims

1. A micro light emitting diode array device, comprising: A driving circuit layer and a dielectric layer disposed above the driving circuit layer; A plurality of columns of light-emitting array strips are arranged in the dielectric layer, each column of the light-emitting array strips comprises a P-type electrode layer and a plurality of light-emitting units arranged one by one on the P-type electrode layer; each of the light-emitting units comprises a light-emitting layer and an N-type electrode layer arranged above the light-emitting layer; The N-type electrode layer is connected to the driving circuit layer through an N-type through hole, and the P-type electrode layer is connected to the driving circuit layer through a P-type through hole.

2. A micro light emitting diode array device as claimed in claim 1, wherein: The light emitting array strips are evenly distributed in the dielectric layer.

3. A micro light emitting diode array device as claimed in claim 1, wherein: The P-type electrode layer and the light-emitting layer on the P-type electrode layer are both arranged inside the dielectric layer, and the N-type electrode layer is arranged outside the dielectric layer.

4. A micro light emitting diode array device as claimed in claim 3, wherein: There is a gap between the P-type electrode layer and the driving circuit layer, and the gap is filled with the dielectric layer.

5. A micro light emitting diode array device as claimed in any one of claims 1 to 4, wherein: The N-type electrode layer is connected to an N-contact plate arranged in the driving circuit layer through the N-type through hole; each of the N-type through holes is connected to a corresponding N-contact plate.

6. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: The P-type electrode layer is connected to the P contact plate arranged in the driving circuit layer through the P-type through hole; each of the P-type through holes is connected to a corresponding P contact plate, and each light-emitting array band is only provided with a corresponding P-type through hole and its connected P contact plate.

7. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: The N-type electrode layer is a transparent electrode.

8. A micro light emitting diode array device as claimed in any one of claims 1 to 4, wherein: The P-type electrode layer includes any one or more of ITO, nickel, gold, indium and copper.

9. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: The light-emitting units in the same row of the light-emitting array strips are arranged at equal intervals.

10. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: The projection size of each column of the light emitting array strips on the driving circuit layer is the same.

11. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: The projection sizes of the light-emitting units in the same column of the light-emitting array strip on the driving circuit layer are the same.

12. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: The P-type electrode layer and the driving circuit layer in different columns of the light emitting array strips have the same vertical distance.

13. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: In the arrangement direction of the light-emitting array strips of several columns, the P-type electrode layer has the same width as the light-emitting units thereon.

14. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: The N-type electrode layers in the same column of the light-emitting array strips are arranged at equal intervals.

15. A micro light emitting diode array device according to any one of claims 1 to 4, wherein: In the arrangement direction of the light-emitting array strips in several columns, any two adjacent N-type electrode layers have the same spacing.

16. A method for preparing a micro light emitting diode array device, wherein: For preparing the micro light emitting diode array device as claimed in claim 1, comprising: A gallium nitride substrate, a dielectric layer, an N-type gallium nitride, a multi-layer quantum well and a P-type gallium nitride are sequentially grown on a silicon substrate to obtain a light-emitting diode epitaxial wafer; wherein the multi-layer quantum well is a light-emitting layer; A light-emitting array is manufactured on the light-emitting diode epitaxial wafer, and a silicon-based CMOS wafer is used as a driving circuit; wherein a P-type contact pad and an N-type contact pad are arranged on the silicon-based CMOS wafer, and the light-emitting array includes a plurality of columns of light-emitting array strips; In the light-emitting array, the common anode and each cathode of the light-emitting array strip in the same row are independently connected to the driving circuit through the corresponding through holes until all the light-emitting array strips in all rows are connected to the driving circuit; Connecting the light emitting diode epitaxial wafer to the driving circuit by hybrid bonding, thereby realizing the combination of the P-type through hole of the common anode and the P contact pad of the driving circuit; After wafer bonding, N-type through-hole metal of each cathode is made to connect with the driving circuit, and an N-type electrode layer is made; The dielectric layer is filled to complete the preparation of the micro light emitting diode array device.

17. The method for preparing a micro light emitting diode array device according to claim 16, wherein: The light emitting array strips are evenly distributed in the dielectric layer.

18. The method for preparing a micro light emitting diode array device according to claim 16, wherein: The P-type electrode layer and the light-emitting layer on the P-type electrode layer are both arranged inside the dielectric layer, and the N-type electrode layer is arranged outside the dielectric layer.

19. The method for preparing a micro light emitting diode array device according to claim 18, wherein: There is a gap between the P-type electrode layer and the driving circuit layer, and the gap is filled with the dielectric layer.

20. The method for preparing a micro light emitting diode array device according to any one of claims 16 to 19, wherein: The N-type electrode layer is connected to an N-contact plate arranged in the driving circuit layer through the N-type through hole; each of the N-type through holes is connected to a corresponding N-contact plate.

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