Perovskite quantum dot rgb micro-led backlight device and preparation method
By combining a blue MicroLED chip and a perovskite quantum dot film layer prepared from the same source, the problems of high packaging and testing costs and complex driving circuits in RGB MicroLED backlight solutions are solved, achieving efficient and low-cost RGB backlight output to meet the needs of high-end displays.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU SIKELET OPTOELECTRONICS TECHNOLOGY CO LTD
- Filing Date
- 2026-02-27
- Publication Date
- 2026-05-29
AI Technical Summary
Existing RGB MicroLED backlight solutions suffer from high packaging and testing costs and complex driver circuit designs due to differences in the material systems of MicroLED chips of different colors. Furthermore, the different operating voltages of MicroLED chips of different colors increase the design difficulty and hardware cost of driver ICs.
Using three blue MicroLED chips fabricated from the same source as the base, color conversion is achieved by setting red and green perovskite quantum dot films on their light-emitting surfaces respectively. Combined with a single-channel synchronous driving architecture, the driving circuit design is simplified, and the uniform mixing of RGB three-color light is achieved by using a high thermal conductivity AlN substrate and an optical homogenizing module.
It effectively reduces packaging and testing costs by 40%-50%, simplifies driver circuit design by 30%-40%, achieves 100% BT2020 color gamut coverage, ensures high stability and high uniformity of backlight output, and reduces hardware costs by 30%-40%.
Smart Images
Figure CN122121385A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor display technology, specifically to a perovskite quantum dot RGB MicroLED backlight device and its fabrication method. Background Technology
[0002] As display technology advances towards higher color gamut, higher resolution, and higher dynamic range, RGB MicroLED backlighting has become a core research direction in the high-end display field due to its advantages such as high brightness, fast response speed, and long lifespan. In backlighting applications, existing RGB MicroLED backlighting solutions mainly use three different wavelengths of MicroLEDs (red, green, and blue light) as three-color light sources, which are arranged in an array on a light-emitting substrate to achieve RGB backlight output, thereby achieving a wider color gamut and better image quality. However, current RGB MicroLED backlight solutions suffer from inherent differences in emission wavelength, operating voltage, and brightness due to the use of different material systems for red, green, and blue MicroLED chips. For example, red chips typically use AlGaInP, while green / blue chips use GaN. To ensure color uniformity in the backlight module, a massive number of chips must be meticulously sorted, i.e., binning and binning. This process is extremely complex and has limited yield, leading to increased packaging and testing costs for RGB MicroLED backlight solutions. Furthermore, since different colored MicroLED chips operate at different voltages—for example, red MicroLEDs operate at approximately 1.8–2.2V, while green / blue MicroLEDs operate at approximately 2.8–3.2V—the light-emitting substrate must provide independent driving channels and power management for each or each group of different colored MicroLED chips. This significantly increases the design difficulty of the driver IC, the complexity of the backplane wiring, and the overall hardware cost. Summary of the Invention
[0003] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a perovskite quantum dot RGB MicroLED backlight device and its preparation method, which solves the problems of high packaging and testing costs and complex driving circuit design in the prior art RGB MicroLED backlight scheme that uses three different wavelengths of MicroLED as three color light sources.
[0004] To achieve the above and other related objectives, the present invention provides a perovskite quantum dot RGB MicroLED backlight device, comprising: A light-emitting substrate, wherein at least one light-emitting unit is integrated on the light-emitting substrate, the light-emitting unit is composed of three blue MicroLED chips fabricated from the same source, the three blue MicroLED chips have the same emission wavelength and the same driving voltage, and are arranged in a preset geometric pattern; The color conversion layer includes a red perovskite quantum dot film and a green perovskite quantum dot film. The red perovskite quantum dot film and the green perovskite quantum dot film are independently disposed on the light-emitting surfaces of two of the blue MicroLED chips as red light sources and green light sources, respectively. The third blue MicroLED chip that is not covered serves as a blue light source. The red light source, green light source, and blue light source together constitute RGB three-color light-emitting points. The driving module is electrically connected to the three blue MicroLED chips. The driving module adopts a single-channel synchronous driving architecture to output the same driving signal to the three blue MicroLED chips. An optical homogenizing module is disposed on the light emission path of the light-emitting unit and is used to mix RGB three-color light evenly.
[0005] In one embodiment of the present invention, the emission wavelengths of the three blue MicroLED chips are all 445nm-455nm, the driving voltage deviations are all ≤±5%, and the three blue MicroLED chips are arranged in an equilateral triangle array, with a spacing of 50-200μm between adjacent blue MicroLED chips.
[0006] In one embodiment of the present invention, the material of the red perovskite quantum dot film is CsPbI3, which is used to convert blue light into red light with a peak wavelength of 620nm-630nm; the material of the green perovskite quantum dot film is CsPbBr3, which is used to convert blue light into green light with a peak wavelength of 525nm-535nm.
[0007] In one embodiment of the present invention, the thickness of the red perovskite quantum dot film is 8-15 μm, and the thickness of the green perovskite quantum dot film is 6-12 μm.
[0008] In one embodiment of the present invention, the optical uniform light module includes a microlens array and a diffuser plate. The diffuser plate is disposed at the upper end of the light-emitting unit for uniform backlight output; the microlens array is disposed above the diffuser plate for converging three-color light.
[0009] In one embodiment of the present invention, the driving module has a built-in brightness calibration unit, which adjusts the pulse width or amplitude of the driving signal to adjust the luminous brightness of the three blue MicroLED chips.
[0010] In one embodiment of the present invention, the light-emitting substrate is a high thermal conductivity AlN substrate with a thermal conductivity of ≥170W / (m·K), and the three blue MicroLED chips are fixed on the AlN substrate by flip-chip bonding and are completely encapsulated with encapsulant.
[0011] This invention provides a method for fabricating a perovskite quantum dot RGB MicroLED backlight device, comprising the following steps: S1. Same-die chip fabrication: Provide an epitaxial wafer, and fabricate three blue MicroLED chips with the same structure on the same epitaxial wafer through photolithography and etching processes to form a same-die chip group; S2. Chip transfer and bonding: The same die chip group is transferred and fixed onto the light-emitting substrate, and electrode connections are made between the same die chip group and the light-emitting substrate. S3. Quantum dot color conversion layer preparation: A red perovskite quantum dot film and a green perovskite quantum dot film are prepared on the light-emitting surfaces of the two blue MicroLED chips in the same die chip group, respectively. The third blue MicroLED chip is not treated. S4. Optical Module Integration and Packaging: On top of the chipset after the color conversion layer has been prepared, an optical homogenizing module is assembled and then packaged as a whole. S5. Drive Connection and Calibration: Connect the drive module electrically to the light-emitting substrate, and adjust the brightness of the three blue MicroLED chips through the brightness calibration unit built into the drive module to complete the device debugging.
[0012] In one embodiment of the present invention, in step S3, perovskite quantum dot material is coated onto the surface of the corresponding blue MicroLED chip using inkjet printing or precision dispensing. Subsequently, annealing is performed in an inert gas atmosphere at a temperature of 120-150°C for 30-60 minutes to form a solid-state preparation of red and green perovskite quantum dot films.
[0013] In one embodiment of the present invention, in step S2, a flip-chip bonding process is used to fix the same die chip group onto the light-emitting substrate, and then the growth substrate of the epitaxial wafer is removed by laser lift-off.
[0014] As described above, the perovskite quantum dot RGB MicroLED backlight device and its fabrication method of the present invention have the following beneficial effects: 1. This invention uses three identical blue MicroLED chips fabricated from the same source, which can fundamentally eliminate parameter differences between multi-color MicroLED chips and completely avoid complex binning and binning processes. This not only effectively reduces packaging and testing costs but also simplifies the chip transfer and mass bonding processes, thereby reducing the packaging and manufacturing costs of backlight devices from the source. Furthermore, since the voltage and current characteristics of the three blue MicroLED chips are completely identical, a single-channel synchronous driving architecture can be adopted in the driving circuit design. Compared with traditional solutions, the number of driving circuit components can be reduced by more than 50%, and the hardware cost can be reduced by 30%-40%. At the same time, the design complexity of the backlight device is also significantly reduced, further reducing the manufacturing cost of the backlight device.
[0015] 2. This invention uses cadmium-free, high-performance perovskite solid quantum dot materials for color conversion. The full width at half maximum (FWHM) of perovskite red quantum dots is ≤20nm, and that of perovskite green quantum dots is ≤18nm, resulting in extremely high color purity. Through driving modes and precise control, it can easily achieve 100% coverage of the BT2020 color gamut, achieving an industry-leading ultra-high color gamut. Furthermore, due to the extremely high stability of solid quantum dots, the color gamut decay is minimal under harsh environments such as high temperature and high humidity, meeting the requirements of top-tier display devices.
[0016] 3. The fabrication method employed in this invention integrates three homogeneous blue MicroLED chips on the same epitaxial wafer, fundamentally eliminating wavelength and voltage differences between multiple chips and completely avoiding the complex binning and binning process in traditional RGB solutions, thus reducing packaging and testing costs by 40%-50%. Simultaneously, this invention utilizes a single-channel synchronous drive architecture based on chip voltage consistency, significantly simplifying circuit design and reducing control circuit hardware costs by 30%-40%. Furthermore, by precisely coating cadmium-free perovskite solid quantum dots on a high thermal conductivity substrate and optimizing the annealing process, efficient and high-purity conversion of red and green light can be achieved, resulting in 100% BT2020 color gamut coverage for the backlight module, with minimal color gamut attenuation under high temperature, high humidity, and high temperature environments. This method also integrates brightness calibration and optical homogenization design to ensure backlight uniformity. Ultimately, while significantly reducing manufacturing costs, it achieves ultra-high color gamut, high stability, and high uniformity backlight output, providing a cost-effective and performance-advantageous industrial solution for the high-end display field. Attached Figure Description
[0017] Figure 1 The diagram shown is a cross-sectional view of the perovskite quantum dot RGB MicroLED backlight device disclosed in this invention.
[0018] Figure 2The image shown is a top view of a blue MicroLED chip group with three MicroLED chips arranged in an equilateral triangle in the perovskite quantum dot RGB MicroLED backlight device disclosed in this invention.
[0019] Figure 3 The diagram shown is a schematic of the perovskite quantum dot RGB MicroLED backlight device package disclosed in this invention.
[0020] Figure 4 The flowchart shown is a process for fabricating the perovskite quantum dot RGB MicroLED backlight device disclosed in this invention.
[0021] Component designation explanation 1. Light-emitting substrate; 2. MicroLED chip; 3. Red perovskite quantum dot film; 4. Green perovskite quantum dot film; 5. Driving module; 6. Microlens array; 7. Diffuser plate. Detailed Implementation
[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.
[0023] Please see Figures 1 to 4 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of the invention, should fall within the scope of the disclosed technical content. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.
[0024] Example 1, please refer to Figure 1 - Figure 3This embodiment provides a perovskite quantum dot RGB MicroLED backlight device, including a light-emitting substrate 1, a color conversion layer, a driving module 5, and an optical homogenizing module. The light-emitting substrate 1 integrates at least one light-emitting unit, which consists of three homogeneously fabricated blue MicroLED chips 2. The three blue MicroLED chips 2 have the same emission wavelength and driving voltage, and are arranged in a preset geometric pattern. Specifically, the emission wavelengths of the three blue MicroLED chips 2 are all 445nm-455nm, the driving voltage deviations are all ≤±5%, and the three blue MicroLED chips 2 are arranged in an equilateral triangular array. The spacing between adjacent blue MicroLED chips 2 is 50-200μm to ensure uniform mixing of the three colors. The light-emitting substrate 1 is a high thermal conductivity AlN substrate with a thermal conductivity ≥170W / (m·K). The three blue MicroLED chips 2 are fixed to the AlN substrate using flip-chip bonding and are entirely encapsulated with a high-transmittance encapsulating adhesive. The optical homogenizing module is disposed on the light output path of the light-emitting unit and is used to mix the RGB three-color light evenly. Specifically, the optical homogenizing module includes a microlens array 6 and a diffuser plate 7. The diffuser plate 7 is disposed at the upper end of the light-emitting unit and is used to uniformly output backlight. The microlens array 6 is disposed above the diffuser plate 7 and is used to converge the three-color light.
[0025] The color conversion layer comprises a red perovskite quantum dot film 3 and a green perovskite quantum dot film 4. The red perovskite quantum dot film 3 is made of CsPbI3 and is used to convert blue light into red light with a peak wavelength of 620nm-630nm. The green perovskite quantum dot film 4 is made of CsPbBr3 and is used to convert blue light into green light with a peak wavelength of 525nm-535nm. The thickness of the red perovskite quantum dot film 3 is 8-15μm, and the thickness of the green perovskite quantum dot film 4 is 6-12μm. The red perovskite quantum dot film 3 and the green perovskite quantum dot film 4 are independently disposed on the light-emitting surfaces of two of the blue MicroLED chips 2 as red light sources and green light sources, respectively. The uncovered third blue MicroLED chip 2 serves as a blue light source. The red, green, and blue light sources together constitute RGB three-color light-emitting points.
[0026] The driving module 5 is electrically connected to the three blue MicroLED chips 2. The driving module 5 adopts a single-channel synchronous driving architecture to output the same driving signal to the three blue MicroLED chips 2. The driving module 5 has a built-in brightness calibration unit. The brightness calibration unit adjusts the pulse width or amplitude of the driving signal to adjust the light emission brightness of the three blue MicroLED chips 2 in order to compensate for the efficiency difference of the color conversion layer.
[0027] This invention uses three identical blue MicroLED chips 2, prepared from the same source, which can fundamentally eliminate parameter differences between multi-color MicroLED chips 2 and completely avoid complex binning and binning processes. This not only effectively reduces packaging and testing costs but also simplifies the process difficulty of chip transfer and mass bonding, thereby reducing the packaging and manufacturing costs of backlight devices from the source. Furthermore, since the voltage and current characteristics of the three blue MicroLED chips 2 are completely identical, a single-channel synchronous driving architecture can be adopted in the driving circuit design. Compared with traditional solutions, the number of driving circuit components can be reduced by more than 50%, and the hardware cost can be reduced by 30%-40%. At the same time, the design complexity of the backlight device is also significantly reduced, further reducing the manufacturing cost of the backlight device.
[0028] Existing solutions also employ traditional quantum dots such as CdSe quantum dots or phosphors for color conversion. However, due to limitations in the optical properties of the materials themselves, it is difficult to achieve 100% coverage of the BT2020 color gamut, and the color purity and color gamut stability under complex scenarios cannot meet the requirements of high-end displays. This invention uses cadmium-free, high-performance perovskite solid-state quantum dot materials for color conversion. The full width at half maximum (FWHM) of perovskite red quantum dots is ≤20nm, and that of perovskite green quantum dots is ≤18nm, resulting in extremely high color purity. Through driving modes and precise control, 100% coverage of the BT2020 color gamut can be easily achieved, realizing an industry-leading ultra-high color gamut. Furthermore, due to the extremely high stability of solid-state quantum dots, the color gamut attenuation is ≤2% under complex and harsh environmental conditions such as -40℃ to 85℃ and RH≥90% humidity. The color conversion performance of perovskite solid-state quantum dot materials is far superior to that of traditional quantum dot materials, meeting the requirements of top-tier display devices.
[0029] Example 2, please refer to Figure 4 This embodiment provides a method for fabricating a perovskite quantum dot RGB MicroLED backlight device, including the following steps: S1. Same-die chip fabrication: Provide an epitaxial wafer, and fabricate three identical blue MicroLED chips 2 on the same epitaxial wafer through photolithography and etching processes to form a same-die chip group; the three MicroLED chips are fabricated using the same die, and their emission wavelength, voltage, brightness and other parameters are highly consistent, eliminating the need for bin mixing and bin sorting processes, simplifying the packaging and testing process by more than 60%, and reducing packaging and testing costs by 40%-50%; at the same time, same-die integration reduces chip handling and sorting steps, further improving production efficiency.
[0030] S2. Chip transfer and bonding: The same die chip group is transferred and fixed onto the light-emitting substrate 1 using flip-chip bonding process, and electrode connections are made between the same die chip group and the light-emitting substrate 1. Then, the growth substrate of the epitaxial wafer is removed by laser lift-off. S3. Quantum Dot Color Conversion Layer Preparation: A red perovskite quantum dot film layer 3 and a green perovskite quantum dot film layer 4 are prepared on the light-emitting surfaces of the two blue MicroLED chips 2 in the same die chip group, respectively. Specifically, perovskite quantum dot material is coated onto the surface of the corresponding blue MicroLED chip 2 using inkjet printing or precision dispensing process, and then annealed in an inert gas atmosphere at a temperature of 120-150℃ for 30-60 minutes to form a solid-state preparation of the red perovskite quantum dot film layer 3 and the green perovskite quantum dot film layer 4; the third blue MicroLED chip 2 is not treated.
[0031] S4. Optical Module Integration and Packaging: An optical homogenizing module is assembled on top of the chipset after the color conversion layer has been prepared, and the entire module is packaged. The AlN substrate is packaged with high-transmittance silicone to ensure that the chip operating temperature is ≤70℃ and the service life is increased to more than 100,000 hours. The device has a compact structure and a wide range of applications.
[0032] S5. Driving Connection and Calibration: The driving module 5 is electrically connected to the light-emitting substrate 1, and the brightness of the three blue MicroLED chips 2 is adjusted through the brightness calibration unit built into the driving module 5 to complete the device debugging. The driving voltage of the three MicroLED chips is consistent, which can adopt a single-channel synchronous driving architecture, abandoning the multi-channel independent driving design of the traditional solution. The number of control circuit components is reduced by more than 50%, the circuit design complexity is reduced, and the hardware cost is reduced by 30%-40%.
[0033] The fabrication method employed in this invention integrates three homogeneous blue MicroLED chips 2 on the same epitaxial wafer, fundamentally eliminating wavelength and voltage differences between multiple chips and completely avoiding the complex binning and binning process in traditional RGB solutions, thus reducing packaging and testing costs by 40%-50%. Simultaneously, this invention utilizes a single-channel synchronous drive architecture based on the voltage consistency of the same chips, significantly simplifying circuit design and reducing control circuit hardware costs by 30%-40%. Furthermore, by precisely coating cadmium-free perovskite solid quantum dots on a high thermal conductivity substrate and optimizing the annealing process, efficient and high-purity conversion of red and green light can be achieved, enabling the backlight module to achieve 100% BT2020 color gamut coverage, with minimal color gamut attenuation under high temperature, high humidity, and high temperature environments. This method also integrates brightness calibration and optical uniformity design to ensure backlight uniformity. Ultimately, while significantly reducing manufacturing costs, it achieves ultra-high color gamut, high stability, and high uniformity backlight output, providing a cost-effective and performance-advantageous industrial solution for the high-end display field.
[0034] Example 3: Based on the above examples, the core parameters of the perovskite quantum dot RGB MicroLED backlight device in this example are as follows: Light-emitting unit: Three blue MicroLED chips 2 are used. The size of each MicroLED chip 2 is 10μm, the emission wavelength is 450nm, the rated driving voltage is 3.0V, and the voltage deviation is ±3%. The three MicroLED chips 2 are arranged in an equilateral triangle with a spacing of 100μm. The maximum brightness of each chip is 8000cd / m². Perovskite solid-state quantum dot color conversion layer: Red quantum dots are CsPbI3 material, with a particle size of 15nm, a light conversion efficiency of 93%, color coordinates (0.71, 0.29), and a layer thickness of 10μm; Green quantum dots are CsPbBr3 material, with a particle size of 10nm, a light conversion efficiency of 95%, color coordinates (0.15, 0.85), and a layer thickness of 8μm; Blue chip color coordinates (0.14, 0.05); Drive module 5: A single-channel MOSFET driver chip is used as drive module 5, with a drive current range of 0-20mA, brightness adjustment accuracy of 16bit, and synchronization response time ≤50ns; Optical homogenizing module: Microlens array 6 with a diameter of 50μm and a numerical aperture of 0.5; diffuser plate 7 is made of frosted acrylic material with a thickness of 1.0mm and a haze of 85%; Packaging structure: AlN substrate thickness 300μm, thermal conductivity 180W / (m·K); encapsulant light transmittance 99%, thermal conductivity 1.5W / (m·K).
[0035] The preparation method of this embodiment includes the following steps: S1. A GaN-based epitaxial layer is grown on a sapphire substrate using MOCVD technology. The chip pattern is defined by deep ultraviolet lithography, and three independent blue MicroLED chips with identical structural dimensions are fabricated on the same die using ICP etching technology (etching gas Cl2 / BCl3=3:1). After completion, electrode evaporation and surface cleaning are performed. In this step, the growth temperature of the GaN buffer layer is 1050℃, the growth temperature of the n-GaN layer is 1150℃, the growth temperature of the multi-quantum-well light-emitting layer is 780℃, and the growth temperature of the p-GaN layer is 1000℃. The ICP etching parameters are: etching gas Cl2 / BCl3=3:1, etching power 200W, and etching rate 60nm / min.
[0036] S2. The prepared same-die chip assembly is precisely bonded to the AlN substrate using a flip-chip bonding process. Subsequently, the sapphire substrate is removed using laser lift-off technology. In this step, the flip-chip bonding process is carried out at a temperature of 260°C and a pressure of 20 MPa.
[0037] S3. Using high-precision dispensing equipment, precisely coat the surface of one MicroLED chip 2 with 20 mg / mL CsPbI3 red quantum dot adhesive; similarly, precisely coat the surface of another MicroLED chip 2 with 18 mg / mL CsPbBr3 green quantum dot adhesive. The surface of the third MicroLED chip 2 is left uncoated. Then, place the light-emitting substrate 1 in an annealing furnace under a nitrogen protective atmosphere and anneal at 130-140℃ for 30-45 minutes to cure the quantum dot adhesive into a solid film layer. In this step, the concentration of the red quantum dot adhesive is 20 mg / mL, the annealing temperature is 130℃, and the annealing time is 45 min; the concentration of the green quantum dot adhesive is 18 mg / mL, the annealing temperature is 140℃, and the annealing time is 30 min; the protective gas is nitrogen with a flow rate of 50 sccm.
[0038] S4. Align and mount the microlens array 6 above the same die chip group after the quantum dot layer has been prepared; then, fix the diffuser plate 7 above the microlens array 6 using a precision bonding process; finally, pour high-transmittance silicone into the entire structure, degas it in a vacuum environment, and then perform thermal curing to form an encapsulation layer; in this step, the vacuum degassing pressure of the encapsulation adhesive is -0.1MPa, the degassing time is 30min, the curing temperature is 150℃, and the curing time is 1.5h.
[0039] S5. Connect the driving module 5 to the electrode pads on the AlN substrate; start the backlight device, and fine-tune the driving parameters of the three MicroLED chips 2 through the brightness calibration unit in the driving module 5. Measure and ensure that the uniformity of the final output backlight is within the required range, thus completing the fabrication of the entire device. In this step, the brightness calibration unit achieves brightness fine-tuning by adjusting the duty cycle of the driving current (adjustment range 0-100%), and the final backlight uniformity deviation after calibration is 2.5%.
[0040] This invention conducts performance tests on the backlight device prepared in Example 3 from four dimensions: optical performance, electrical performance, reliability, and cost-effectiveness. Optical testing uses a spectroradiometer to measure color gamut coverage and full width at half maximum (FWHM), an imaging luminance meter to detect brightness uniformity, an integrating sphere to evaluate quantum dot conversion efficiency, and an oscilloscope to verify response time. Electrical testing ensures voltage consistency among the three homogeneous chips. Reliability testing verifies color gamut and brightness attenuation through high-low temperature cycling and high-temperature, high-humidity aging. Cost evaluation compares the backlight device with traditional solutions, verifying packaging and testing costs and control circuit costs. The results are as follows: 1) Color gamut coverage: 100% coverage of BT2020 color gamut, 100% coverage of DCI-P3 color gamut, 18nm half-width at half-maximum for red quantum dots, 16nm half-width at half-maximum for green quantum dots, with excellent color purity; 2) Brightness and uniformity: Maximum backlight brightness is 9500 cd / m², and the brightness uniformity deviation across the entire area is 2.5%, meeting the requirements of high-end display devices; 3) Cost Comparison: Packaging and testing costs are reduced by 45% compared to traditional solutions, control circuit costs are reduced by 35%, and overall costs are reduced by 40%; 4) Reliability test: After 100 cycles of testing at -40℃ to 85℃, the color gamut decayed by 1.2%; after 1000 hours of continuous operation in an environment with RH=95%, the brightness decayed by ≤2%, demonstrating excellent stability; 5) Response speed: The on response time is 40ns and the off response time is 35ns, which meets the requirements of high dynamic range display.
[0041] In summary, this invention uses three blue MicroLED chips 2 fabricated on the same die as the basic light source. Color conversion is achieved by coating the surfaces of two of the chips with red and green perovskite solid quantum dots. Together with the blue chip without quantum dot coating, they form an RGB three-color backlight. This invention simplifies the control circuit by utilizing the voltage consistency advantage of chips fabricated on the same die, and achieves high color gamut coverage through the excellent optical properties of perovskite solid quantum dots. The compact structure of the same-die chip group, combined with a high thermal conductivity AlN substrate and flip-chip bonding technology, effectively reduces thermal resistance, ensures that the chips operate at a suitable temperature, and extends the overall lifespan of the device. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.
[0042] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.
Claims
1. A perovskite quantum dot RGB MicroLED backlight device, characterized in that, The device includes: The light-emitting substrate (1) has at least one light-emitting unit integrated on it. The light-emitting unit is composed of three blue MicroLED chips (2) fabricated from the same source. The three blue MicroLED chips (2) have the same light-emitting wavelength and the same driving voltage, and are arranged in a preset geometric pattern. The color conversion layer includes a red perovskite quantum dot film (3) and a green perovskite quantum dot film (4). The red perovskite quantum dot film (3) and the green perovskite quantum dot film (4) are independently disposed on the light-emitting surfaces of two of the blue MicroLED chips (2) as red light source and green light source, respectively. The third blue MicroLED chip (2) that is not covered is used as blue light source. The red light source, green light source and blue light source together constitute RGB three-color light-emitting points. The driving module (5) is electrically connected to the three blue MicroLED chips (2). The driving module (5) adopts a single-channel synchronous driving architecture to output the same driving signal to the three blue MicroLED chips (2). An optical homogenizing module is disposed on the light emission path of the light-emitting unit and is used to mix RGB three-color light evenly.
2. The perovskite quantum dot RGB MicroLED backlight device according to claim 1, characterized in that: The three blue MicroLED chips (2) have emission wavelengths of 445nm-455nm and driving voltage deviations of ≤±5%. The three blue MicroLED chips (2) are arranged in an equilateral triangle array, and the spacing between two adjacent blue MicroLED chips (2) is 50-200μm.
3. The perovskite quantum dot RGB MicroLED backlight device according to claim 1, characterized in that: The red perovskite quantum dot film (3) is made of CsPbI3 and is used to convert blue light into red light with a peak wavelength of 620nm-630nm; the green perovskite quantum dot film (4) is made of CsPbBr3 and is used to convert blue light into green light with a peak wavelength of 525nm-535nm.
4. The perovskite quantum dot RGB MicroLED backlight device according to claim 3, characterized in that: The thickness of the red perovskite quantum dot film (3) is 8-15 μm, and the thickness of the green perovskite quantum dot film (4) is 6-12 μm.
5. The perovskite quantum dot RGB MicroLED backlight device according to claim 1, characterized in that: The optical uniform light module includes a microlens array (6) and a diffuser plate (7). The diffuser plate (7) is located at the top of the light-emitting unit and is used for uniform backlight output. The microlens array (6) is located above the diffuser plate (7) and is used to converge the three colors of light.
6. The perovskite quantum dot RGB MicroLED backlight device according to claim 1, characterized in that: The driving module (5) has a built-in brightness calibration unit, which adjusts the pulse width or amplitude of the driving signal to adjust the luminous brightness of the three blue MicroLED chips (2).
7. The perovskite quantum dot RGB MicroLED backlight device according to claim 1, characterized in that: The light-emitting substrate (1) is a high thermal conductivity AlN substrate with a thermal conductivity of ≥170W / (m·K). The three blue MicroLED chips (2) are fixed on the AlN substrate by flip-chip bonding and are completely covered by encapsulating glue.
8. A method for fabricating a perovskite quantum dot RGB MicroLED backlight device, characterized in that, Includes the following steps: S1. Same-die chip fabrication: Provide an epitaxial wafer, and fabricate three blue MicroLED chips with the same structure on the same epitaxial wafer through photolithography and etching processes (2) to form a same-die chip group; S2, Chip Transfer and Bonding: The same die chip group is transferred and fixed onto the light-emitting substrate (1), and electrode connections are made between the same die chip group and the light-emitting substrate (1); S3, Quantum dot color conversion layer preparation: Red perovskite quantum dot film layer (3) and green perovskite quantum dot film layer (4) are prepared on the light-emitting surfaces of the two blue MicroLED chips (2) in the same die chip group, respectively. The third blue MicroLED chip (2) is not treated. S4. Optical Module Integration and Packaging: On top of the chipset after the color conversion layer has been prepared, an optical homogenizing module is assembled and then packaged as a whole. S5. Drive connection and calibration: Connect the drive module (5) to the light-emitting substrate (1) and adjust the brightness of the three blue MicroLED chips (2) through the built-in brightness calibration unit of the drive module (5) to complete the device debugging.
9. The method for fabricating the perovskite quantum dot RGB MicroLED backlight device according to claim 8, characterized in that: In step S3, perovskite quantum dot material is coated onto the surface of the corresponding blue MicroLED chip (2) using inkjet printing or precision dispensing. Then, it is annealed in an inert gas atmosphere at a temperature of 120-150°C for 30-60 minutes to form a solid red perovskite quantum dot film (3) and a green perovskite quantum dot film (4).
10. The method for fabricating the perovskite quantum dot RGB MicroLED backlight device according to claim 8, characterized in that: In step S2, the same die chip group is fixed to the light-emitting substrate (1) using flip-chip bonding process, and then the growth substrate of the epitaxial wafer is removed by laser lift-off.