Preparation method of monolithic integrated common-cathode full-color Micro LED device
By adopting the preparation method of a single-chip integrated co-colon full-color Micro LED device in Micro LED display technology, graphene quantum dot and gas phase doping technology, the problems of complex processes of traditional Micro LED devices and low solid crystal yield of quantum dot Micro LED are solved, achieving efficient and uniform full-color display effect.
Patent Information
- Application Number
- CN202411882268.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-03-11
AI Technical Summary
In the existing Micro LED display technology, traditional Micro LED devices need independent red, green and blue chips to achieve full color display, which is complex and difficult; while the solid crystal yield of quantum dot Micro LED is low, costly, and there is a technical bottleneck in color uniformity and ink color consistency.
Using a single-chip integrated co-colon full-color Micro LED device, a graphene quantum dot is sprayed onto the surface of the Micro LED light emitting device, and a gas-phase doping technology is used to divide it into three light areas: red, green and blue, to achieve full-color display.
It reduces the difficulty of the Micro LED full-color process, improves color uniformity and ink color consistency, reduces process flow and chip count, reduces cost and power consumption, and improves the success rate and reliability of the device.
Smart Images
Figure CN119604097A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of Micro LED display technology and relates to a method for preparing a monolithic integrated common cathode full-color Micro LED device. Background Art
[0002] Quantum dot LED (QLED) is a new display technology that combines quantum dot materials and LED technology. Quantum dot materials are considered to be an excellent luminescent and optoelectronic material due to their unique optical properties, such as continuously adjustable full-spectrum luminescence peaks, high color purity, and good stability. Quantum dot display technology uses these special properties to achieve high-performance, low-cost displays.
[0003] Traditional Micro LED devices need to emit red, green and blue light, which requires three independent chips. The process is complex and difficult. Quantum dot LED uses blue light or ultraviolet LED to emit light. When the blue light passes through the quantum dot film, part of the blue light is converted into green and red light by the quantum dots, which together with the unconverted blue light form white light, thereby improving the color gamut and color purity of the LCD display. However, the current ordinary quantum dot Micro LED chip bonding yield is low and requires high-cost repair. In addition, the consistency and uniformity of ink color are the core bottlenecks of the technology. Summary of the invention
[0004] The present invention overcomes the shortcomings of the prior art and proposes a method for preparing a monolithic integrated common cathode full-color Micro LED device; solves the problem of Micro LED full colorization, quantum dot Micro LED and color uniformity, and reduces the process difficulty; the present invention is achieved through the following technical solutions: A method for preparing a monolithic integrated common cathode full-color Micro LED device comprises the following steps: S1, spraying graphene quantum dots onto the surface of the Micro LED light-emitting device to form a quantum dot coating; S2. Gas phase doping to regulate the luminescence of graphene quantum dots: the quantum dot coating is evenly divided into a red light graphene quantum dot coating area, a green light graphene quantum dot coating area and a blue light graphene quantum dot coating area; First, the red light graphene quantum dot coating area is brought into contact with the N element dopant, and the other areas are blocked, so that the mass percentage concentration of N doping is 5%-10%; then the green light graphene quantum dot coating area to be doped is brought into contact with the N element dopant, and the other areas are blocked, so that the N doping concentration is 0.5%-1%; the blue light graphene quantum dot coating area is not brought into contact with the N element dopant.
[0005] Preferably, the temperature on the surface of the Micro LED light-emitting device is 25-30°C and the humidity is 45-55%.
[0006] Preferably, the thickness of the quantum dot coating is 2-5 μm.
[0007] Preferably, the Micro LED light-emitting device uses a Micro LED ultraviolet chip divided into three areas, the substrate is a sapphire substrate, the electrodes are Cu, Ag or Au electrodes, and a common cathode structure is adopted internally.
[0008] Better yet, the Micro LED UV chip has an area of less than 5000 μm 2 Thin-film LED without substrate.
[0009] Preferably, the N element dopant is ammonia or nitrogen or a nitrogen-containing compound.
[0010] Preferably, the particle size of the graphene quantum dots is 3-6 nm.
[0011] Preferably, in step S1, graphene quantum dots are sprayed onto the surface of the Micro LED light-emitting device, and then placed in a 120° C. oven and baked for 15 minutes to form a quantum dot coating.
[0012] The beneficial effects of the present invention compared with the prior art are as follows: The Micro LED chip technology of the present invention converts a group of common cathode monochromatic LEDs into red, green and blue light through a quantum dot coating, thereby reducing the difficulty of the RGB full-color process, avoiding the yield rate, solving the high-cost rework problem, and at the same time improving the display uniformity.
[0013] The Micro LED chip technology mentioned in the present invention only requires one chip, which not only saves the number of chips, but also reduces the problems that may arise due to multiple die bonding and subsequent processes. Moreover, by reducing the process flow, the process difficulty is also reduced, and the success rate of Micro LED devices is improved. The common cathode design also reduces the power consumption of the device and has energy-saving characteristics. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 Schematic diagram of the Micro LED device structure of the present invention; Figure 2 Schematic diagram of the electrode surface of the Micro LED device of the present invention; Figure 3 Schematic diagram of the light-emitting surface of the Micro LED device of the present invention; Markings in the figure: 1 is the passivation layer, 2 is the P junction, 3 is the N junction, 4 is the sapphire substrate, 5 is the quantum dot coating, 6 is the cathode, 7 is the anode of the red light area controlled by the chip, 8 is the red light area, 9 is the green light area, 10 is the blue light area, 11 is the anode of the green light area controlled by the chip, 12 is the anode of the blue light area controlled by the chip, 13 is the red light graphene quantum dot coating area, 14 is the green light graphene quantum dot coating area, and 15 is the blue light graphene quantum dot coating area. DETAILED DESCRIPTION
[0015] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail in conjunction with the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The technical solutions of the present invention are described in detail below in conjunction with the embodiments and the accompanying drawings, but the scope of protection is not limited thereto.
[0016] Example 1 This embodiment proposes a method for preparing a monolithic integrated common cathode full-color Micro LED device, which is beneficial to reducing the cost of Micro LED rework and improving reliability and color uniformity. The attached figure provides a device structure of a new Micro LED, an electrode surface and a light-emitting surface. Figure 1~Figure 3 , the specific implementation methods of the present invention are described in detail.
[0017] The Micro LED device is composed of a passivation layer 1, a P junction 2, an N junction 3 and a sapphire substrate 4. The passivation layer 1 is composed of a UV coating, and the bottom of the passivation layer 1 is an electrode layer, and the electrode is a Cu, Ag or Au electrode, see Figure 2 The electrode layer adopts an energy-saving common cathode design, in which the cathode 6 is located in a corner of the entire chip. A single UV Micro LED chip is evenly divided into three areas, which are used to control the red light area 8, the blue light area 9 and the green light area 10. The corresponding anodes are respectively the anode 7 of the chip controlling the red light area, the anode 11 of the chip controlling the green light area, and the anode 12 of the chip controlling the blue light area. The size of the entire Micro LED device is 0.2mm×0.2mm.
[0018] The preparation method specifically comprises the following steps: 1. Pour black UV light-shielding glue into the device, making sure the glue is flush with the UV Micro LED chip (the Micro LED chip is less than 5000 μm in area). 2A thin film LED without a substrate is then rapidly cured by 365 nm UV light to form a passivation layer 1; after curing, a P junction 2, an N junction 3, and a sapphire substrate 4 are sequentially installed on the upper surface of the passivation layer 1; then, an ultrasonic spraying device is used to spray a purified graphene suspension on the surface of the sapphire substrate 4, i.e., the light-emitting surface, to form a quantum dot coating 5; the size of the graphene quantum dots in the graphene suspension is in the range of 3-6 nm; During the spraying process, the light-emitting surface of the Micro LED device is kept at a temperature of 25°C and the humidity is controlled at about 50%. The thickness of the graphene quantum dot coating 5 formed by spraying is about 3 μm. Then it is placed in a 120°C oven for 15 minutes to fix the graphene quantum dot coating 5 on the surface of the Micro LED device.
[0019] 2. Select nitrogen as the nitrogen source, place the Micro LED device sprayed with the graphene quantum dot coating 5 into the reaction chamber, and use the shielding device to evenly divide the graphene quantum dot coating 5 into three areas: the red light graphene quantum dot coating area 13, the green light graphene quantum dot coating area 14, and the blue light graphene quantum dot coating area 15; first, let the red light graphene quantum dot coating area 13 to be doped contact with nitrogen, and block the other areas from contacting with nitrogen. The flow rate and proportion of the gas are accurately controlled by the mass flow controller to make the mass percentage concentration of N doping 5%, and the doping atom N is doped into the graphene quantum dots, so that the quantum dot area emits red light. Then let the green light graphene quantum dot coating area 14 to be doped contact with nitrogen, and block the other areas from contacting with nitrogen. The flow rate and proportion of the gas are controlled again to make the N doping concentration 0.5%, and the doping atom N is doped into the graphene quantum dots, so that the quantum dot area emits green light.
[0020] The graphene quantum dot coating is evenly divided into three regions through gas phase doping, wherein the undoped region is the blue light graphene quantum dot coating region 15 which emits blue light, the doping concentration is 5% which emits red light, and the doping concentration is 0.5% which emits green light.
[0021] Example 2 This embodiment proposes a method for preparing a monolithic integrated common cathode full-color Micro LED device, which is beneficial to reducing the cost of Micro LED rework and improving reliability and color uniformity. The attached figure provides a device structure of a new Micro LED, an electrode surface and a light-emitting surface. Figure 1~Figure 3 , the specific implementation methods of the present invention are described in detail.
[0022] The Micro LED device is composed of a passivation layer 1, a P junction 2, an N junction 3 and a sapphire substrate 4. The passivation layer 1 is composed of a UV coating, and the bottom of the passivation layer 1 is an electrode layer, see Figure 2The electrode layer adopts an energy-saving common cathode design, in which the cathode 6 is located in a corner of the entire chip. A single UV Micro LED chip is evenly divided into three areas, which are used to control the red light area 8, the blue light area 9 and the green light area 10. The corresponding anodes are respectively the anode 7 of the chip controlling the red light area, the anode 11 of the chip controlling the green light area, and the anode 12 of the chip controlling the blue light area. The size of the entire Micro LED device is 0.2mm×0.2mm.
[0023] The preparation method specifically comprises the following steps: 1. Pour black UV light-shielding glue into the Micro LED device, flush with the ultraviolet light Micro LED chip, and then quickly cure it through 365nm UV ultraviolet light to form a passivation layer 1; after curing, install the P junction 2, N junction 3, and sapphire substrate 4 on the upper surface of the passivation layer 1 in sequence; then use an ultrasonic spraying device to spray the purified graphene suspension on the surface of the sapphire substrate 4, i.e., the light-emitting surface, to form a quantum dot coating 5; the size of the graphene quantum dots in the graphene suspension is in the range of 3-6 nm; During the spraying process, the light-emitting surface of the Micro LED device is kept at a temperature of 30°C and the humidity is controlled at about 50%. The thickness of the graphene quantum dot coating 5 formed by spraying is about 5μm. Then it is placed in a 120°C oven for 15 minutes to fix the graphene quantum dot coating 5 on the surface of the Micro LED device.
[0024] 2. Ammonia is selected as a nitrogen source, and the Micro LED device sprayed with the graphene quantum dot coating 5 is placed in the reaction chamber. The graphene quantum dot coating 5 is evenly divided into three regions: the red light graphene quantum dot coating region 13, the green light graphene quantum dot coating region 14, and the blue light graphene quantum dot coating region 15 by using a shielding device; first, the red light graphene quantum dot coating region 13 to be doped is contacted with nitrogen, and the other regions are shielded and not in contact with nitrogen. The flow rate and proportion of the gas are accurately controlled by a mass flow controller, so that the mass percentage concentration of N doping is 10%, and the doping atom N is doped into the graphene quantum dots, so that the quantum dot region emits red light. Then, the green light graphene quantum dot coating region 14 to be doped is contacted with nitrogen, and the other regions are shielded and not in contact with nitrogen. The flow rate and proportion of the gas are controlled again, so that the N doping concentration is 1%, and the doping atom N is doped into the graphene quantum dots, so that the quantum dot region emits green light.
[0025] The graphene quantum dot coating is evenly divided into three regions through gas phase doping, wherein the undoped region is the blue light graphene quantum dot coating region 15 which emits blue light, the doping concentration is 10% which emits red light, and the doping concentration is 1% which emits green light.
[0026] Example 3 This embodiment proposes a method for preparing a monolithic integrated common cathode full-color Micro LED device, which is beneficial to reducing the cost of Micro LED rework and improving reliability and color uniformity. The attached figure provides a device structure of a new Micro LED, an electrode surface and a light-emitting surface. Figure 1~Figure 3 , the specific implementation methods of the present invention are described in detail.
[0027] The Micro LED device is composed of a passivation layer 1, a P junction 2, an N junction 3 and a sapphire substrate 4. The passivation layer 1 is composed of a UV coating, and the bottom of the passivation layer 1 is an electrode layer, see Figure 2 The electrode layer adopts an energy-saving common cathode design, in which the cathode 6 is located in a corner of the entire chip. A single UV Micro LED chip is evenly divided into three areas, which are used to control the red light area 8, the blue light area 9 and the green light area 10. The corresponding anodes are respectively the anode 7 of the chip controlling the red light area, the anode 11 of the chip controlling the green light area, and the anode 12 of the chip controlling the blue light area. The size of the entire Micro LED device is 0.2mm×0.2mm.
[0028] The preparation method specifically comprises the following steps: 1. Pour black UV light-shielding glue into the Micro LED device, flush with the ultraviolet light Micro LED chip, and then quickly cure it through 365nm UV ultraviolet light to form a passivation layer 1; after curing, install the P junction 2, N junction 3, and sapphire substrate 4 on the upper surface of the passivation layer 1 in sequence; then use an ultrasonic spraying device to spray the purified graphene suspension on the surface of the sapphire substrate 4, i.e., the light-emitting surface, to form a quantum dot coating 5; the size of the graphene quantum dots in the graphene suspension is in the range of 3-6 nm; During the spraying process, the light-emitting surface of the Micro LED device is kept at a temperature of 27°C and the humidity is controlled at about 50%. The thickness of the graphene quantum dot coating 5 formed by spraying is about 2μm. Then it is placed in a 120°C oven for 15 minutes to fix the graphene quantum dot coating 5 on the surface of the Micro LED device.
[0029] 2. Select nitrogen as the nitrogen source, place the Micro LED device sprayed with the graphene quantum dot coating 5 into the reaction chamber, and use the shielding device to evenly divide the graphene quantum dot coating 5 into three areas: the red light graphene quantum dot coating area 13, the green light graphene quantum dot coating area 14, and the blue light graphene quantum dot coating area 15; first, let the red light graphene quantum dot coating area 13 to be doped contact with nitrogen, and block the other areas from contacting with nitrogen. The flow rate and proportion of the gas are accurately controlled by the mass flow controller to make the mass percentage concentration of N doping 8%, and the doping atom N is doped into the graphene quantum dots, so that the quantum dot area emits red light. Then let the green light graphene quantum dot coating area 14 to be doped contact with nitrogen, and block the other areas from contacting with nitrogen. The flow rate and proportion of the gas are controlled again to make the N doping concentration 0.8%, and the doping atom N is doped into the graphene quantum dots, so that the quantum dot area emits green light.
[0030] The graphene quantum dot coating is evenly divided into three regions through gas phase doping, wherein the undoped region is the blue light graphene quantum dot coating region 15 which emits blue light, the doping concentration is 8% which emits red light, and the doping concentration is 0.8% which emits green light.
[0031] The above content is a further detailed description of the present invention in combination with a specific preferred embodiment. It cannot be determined that the specific embodiments of the present invention are limited to this. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the present invention, which should be regarded as belonging to the present invention and the scope of patent protection determined by the submitted claims.
Claims
1. A method for preparing a monolithically integrated common cathode full-color Micro LED device, characterized in that: The following steps are involved: S1, spraying graphene quantum dots onto the surface of the Micro LED light-emitting device to form a quantum dot coating (5); S2. Gas phase doping to regulate the luminescence of graphene quantum dots: the quantum dot coating (5) is evenly divided into a red light graphene quantum dot coating region (13), a green light graphene quantum dot coating region (14) and a blue light graphene quantum dot coating region (15); First, the red light graphene quantum dot coating region (13) is brought into contact with the N element dopant, while the other regions are shielded, so that the mass percentage concentration of N doping is 5%-10%; then, the green light graphene quantum dot coating region (14) to be doped is brought into contact with the N element dopant, while the other regions are shielded, so that the N doping concentration is 0.5%-1%; the blue light graphene quantum dot coating region (15) is not brought into contact with the N element dopant.
2. The method for preparing a monolithically integrated common cathode full-color Micro LED device according to claim 1, characterized in that: The temperature on the surface of the Micro LED light-emitting device is 25-30°C and the humidity is 45-55%.
3. The method for preparing a monolithically integrated common cathode full-color Micro LED device according to claim 1, characterized in that: The thickness of the quantum dot coating (5) is 2-5 μm.
4. The method for preparing a monolithically integrated common cathode full-color Micro LED device according to claim 1, characterized in that: The Micro LED light-emitting device uses a Micro LED ultraviolet chip divided into three areas. The substrate is a sapphire substrate, the electrodes are Cu, Ag or Au electrodes, and a common cathode structure is adopted internally.
5. The method for preparing a monolithically integrated common cathode full-color Micro LED device according to claim 4, characterized in that: Micro LED UV chip has an area of less than 5000μm 2 Thin-film LED without substrate.
6. The method for preparing a monolithically integrated common cathode full-color Micro LED device according to claim 1, characterized in that: The N element dopant is ammonia or nitrogen or a nitrogen-containing compound.
7. The method for preparing a monolithically integrated common cathode full-color Micro LED device according to claim 1, characterized in that: The particle size of graphene quantum dots is 3-6 nm.
8. The method for preparing a monolithically integrated common cathode full-color Micro LED device according to claim 1, characterized in that: In step S1, graphene quantum dots are sprayed onto the surface of the Micro LED light-emitting device, and then placed in a 120° C. oven for baking for 15 minutes to form a quantum dot coating (5).