Multi-Wavelength Micro-LED Structure for Monolithic RGB Integration
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Solution Overview
Problem
The commercialization of full-color micro-LED displays is hindered by the complexity of the assembly process, which requires precise alignment of red, green, and blue micro-LEDs grown on different wafers, leading to increased production costs and reduced efficiency.
Innovation Solution
A multi-wavelength light-emitting device is developed with a substrate and semiconductor layers having different porosities to emit red, green, and blue light, allowing for monolithic integration of RGB micro-LEDs on the same substrate, eliminating the need for precise alignment and additional color conversion layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If red, green, and blue micro-LEDs are grown on different wafers and assembled on the same TFT, then full color micro-LED display is achieved, but precise alignment is required which limits resolution, lowers production efficiency, and increases production cost
Solution Approach 1:
The patent merges the previously separate R/G/B micro-LED manufacturing processes by growing all three color micro-LEDs on a single substrate simultaneously. This is achieved by forming a single active layer with spatially varying indium composition ratios, where different regions emit different colors (red, green, blue) based on their local composition, eliminating the need for separate wafers and assembly steps.
Solution Approach 2:
The active layer serves multiple functions simultaneously: it acts as the light-emitting layer for all three colors, the structural foundation for R/G/B micro-LEDs, and the medium for achieving wavelength differentiation through composition control. The single substrate supports all three color micro-LEDs, providing multi-functionality that replaces multiple separate manufacturing systems.
2Adaptability or versatility
If red, green, and blue micro-LEDs are grown on different wafers and assembled on the same TFT, then full color micro-LED display is achieved, but precise alignment is required which limits resolution
Solution Approach 1:
The patent eliminates the alignment problem by merging the R/G/B micro-LED structures into a single monolithic device on one substrate. Since all color elements are grown simultaneously in their final positions, no post-growth alignment or transfer processes are needed, thereby achieving high resolution without alignment limitations.
3Device complexity
If monolithic multi-color manufacturing technology is used to manufacture RGB micro-LEDs on the same substrate, then assembly complexity is reduced, but the manufacturing process becomes complicated because the micro-LED growth conditions for each R/G/B are different
Solution Approach 1:
The patent applies local quality by creating spatial variations in the indium composition ratio within the active layer. Different regions of the layer have different compositions optimized for specific colors: higher indium for blue, intermediate for green, and lower for red. This allows each region to have locally optimized growth conditions while maintaining a single continuous layer structure, simplifying the overall manufacturing process.
Solution Approach 2:
The patent changes the indium composition ratio parameter across different regions of the active layer to achieve different emission wavelengths. By controlling the indium content (e.g., InGaN with varying In composition), the emission color is tuned from blue to green to red, allowing single-step growth of multi-color micro-LEDs with different optimal conditions encoded in the composition gradient.
4Adaptability or versatility
If a color conversion layer is used to convert blue light to other colors, then full color display is achieved, but the volume of the display device increases and the manufacturing step becomes complicated
Solution Approach 1:
The patent extracts the color conversion function from a separate physical layer and integrates it directly into the active layer through composition control. Instead of adding a distinct color conversion layer that increases volume, the color differentiation is achieved by varying the indium composition within the existing active layer structure, thereby eliminating the need for additional layers and reducing overall device volume.
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
This approach simplifies the manufacturing process, reduces production costs, and enhances efficiency by enabling the monolithic integration of micro-LEDs with varying porosities, allowing for the direct growth of RGB sub-pixels on a single substrate, thus avoiding the need for complex assembly and color conversion layers.
Implementation Method 1
a first area of the first type semiconductor layer includes a first nanopore, the second area of the first type semiconductor layer includes a second nanopore, and a first porosity of the first area of the first type semiconductor layer is different from a second porosity of the second area of the first type semiconductor layer
Data Source
AI summary
A multi-wavelength light-emitting device configured to emit light of a first wavelength, light of a second wavelength, and a third wavelength, includes a substrate, a first type semiconductor layer provided on the substrate, an active layer provided on the first type semiconductor layer, a second type semiconductor layer provided on the active layer, and an electrode provided on the second type semiconductor layer. The active layer includes a first active area configured to emit the light of the first wavelength, a second active area configured to emit the light of the second wavelength, and a third active area configured to emit the light of the third wavelength.