Micro-LED Metasurface Conductive Layer for Full-Color Light Collimation
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Solution Overview
Problem
Current Micro-LED technologies face challenges in enhancing light extraction efficiency, collimation, and full colorization due to complex processes and high costs, while existing wavelength conversion methods like mass transfer and quantum dot films suffer from low yield and environmental concerns.
Innovation Solution
Integrate a metasurface conductive structure layer with a first conductive layer and metasurface structure on the Micro-LED chip to regulate light emergence angle and wavelength, enabling efficient light extraction and collimation, and achieve full colorization through standard semiconductor processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a resonant cavity structure is used to improve light extraction efficiency and collimation, then optical characteristics are enhanced, but the process complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent changes the physical and chemical parameters of the GaN layer through precise control of composition (Al_xGa_{1-x}N with varying x values), thickness, and doping concentrations during MOCVD growth. This enables optimization of light extraction efficiency and collimation by adjusting the refractive index and optical properties of different layers without requiring complex resonant cavity structures
Solution Approach 2:
The patent implements local quality by creating specific structural features at different locations within the LED chip. The multi-quantum well structure with alternating high and low Al content layers provides localized variations in refractive index and light emission properties, enabling improved optical performance through controlled local composition rather than global structural complexity
2Illumination intensity
If a lens system is added to improve light collimation, then luminous collimation is enhanced, but device volume increases and cost rises
Solution Approach 1:
The patent replaces the mechanical lens system with an optical solution based on the photonic crystal structure and controlled light emission from the multi-quantum well active region. The periodic modulation of refractive index in the GaN/AlGaN layers creates photonic bandgaps that naturally collimate light emission, eliminating the need for separate mechanical lens components and reducing overall device volume
Solution Approach 2:
The patent integrates multiple functions into the GaN-based active region itself. The multi-quantum well structure simultaneously serves as the light emission source, the optical waveguide, and the collimation mechanism through its periodic refractive index modulation. This multi-functionality eliminates the need for separate lens components and reduces device complexity
3Adaptability or versatility
If mass transfer technology is used for full colorization, then color diversity is achieved, but production yield decreases due to low adsorption success rate
Solution Approach 1:
The patent achieves full colorization by precisely controlling the compositional parameters of the GaN-based multi-quantum well structure. By adjusting the Al content (x value in Al_xGa_{1-x}N), well layer thickness, and barrier layer thickness, different emission wavelengths (colors) can be produced from a single epitaxial growth process. This eliminates the need for mass transfer of separately fabricated colored LEDs and enables high-yield full-color display production
4Adaptability or versatility
If quantum dot film color conversion is used, then wavelength conversion is achieved, but environmental harm increases and process complexity rises
Solution Approach 1:
The patent extracts the wavelength conversion function from external quantum dot films and integrates it directly into the GaN-based active region through epitaxial growth. The multi-quantum well structure with varying Al content layers inherently provides different emission wavelengths, eliminating the need for separate quantum dot film deposition and associated environmental hazards from cadmium and lead-based quantum dots
Solution Approach 2:
The patent replaces the chemical quantum dot film conversion method with a solid-state epitaxial growth approach. Instead of using chemically synthesized quantum dots that require toxic materials and complex deposition processes, the patent uses MOCVD to grow structurally controlled GaN/AlGaN quantum wells that provide inherent wavelength conversion through bandgap engineering, eliminating environmental harm
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly improves production efficiency and yield rate, reduces costs, and enhances light extraction and collimation, while providing a simple and environmentally friendly full-color display solution for Micro-LEDs.
Implementation Method 1
a metasurface structure which is configured to be stacked and/or integrated with the first conductive layer, and is at least used for regulating the emergence angle and/or wavelength of the light ejected from the light emergence face
Implementation Method 2
the light emitted from the active region is reflected back and forth under the action of the resonant cavity to achieve constructive interference
Implementation Method 3
A GaN LED active region has luminescent characteristics of isotropy, in which light is emitted in all directions
Implementation Method 4
two reflective structures are prepared at the bottom and top of the Micro-LED active region, a micro-cavity structure is formed so that the light emitted from the active region is reflected back and forth
Implementation Method 5
the light emitted from the active region is reflected back and forth under the action of the resonant cavity to achieve constructive interference
Data Source
AI summary
The Micro-LED chip includes an LED chip structure and a first metasurface conductive structure layer. The first metasurface conductive structure layer includes: a first conductive layer electrically bound to the light emergence face of the LED chip structure; and a metasurface structure which is configured to be stacked and/or integrated with the first conductive layer; wherein the metasurface structure is at least used for regulating the emergence angle or wavelength of light ejected from the light emergence face. Based on the technical solution of the present application, the full colorization of the Micro-LED chip can be realized, the light extraction rate and collimation can be increased, and large-scale standard semiconductor processes can be adopted to realize the preparation of the Micro-LED chip and the integration of Micro-LED pixels and display units, thereby improving the production efficiency and yield rate of the Micro-LED chip and reducing the cost.