Micro LED Chalcopyrite Conversion Layer for Filter-Free Displays
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Solution Overview
Problem
Conventional wavelength conversion technologies for micro LEDs require thick layers of fluorescent materials or phosphors, leading to complex structures, increased cost, and reduced productivity due to low absorption coefficients and the need for additional components like color filters, which affect light output and color reproducibility.
Innovation Solution
A micro LED with a thin wavelength conversion layer made of chalcopyrite-structure semiconductors is integrated directly on the light emission surface, eliminating the need for a cover layer and color filter, and a display module with micro LEDs arranged in pixel units on a TFT substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluorescent materials or phosphors are used for wavelength conversion, then the light conversion function is achieved, but the layer thickness increases and structure becomes complex
Solution Approach 1:
The patent changes the material parameter by using quantum dots with specific size control (2-50 nm) to achieve high absorption coefficient, allowing thin layer deposition while maintaining wavelength conversion function. This resolves the contradiction between achieving reliable wavelength conversion and minimizing layer thickness.
Solution Approach 2:
The patent creates a composite structure by combining quantum dots with specific matrix materials (resin, polymer, or glass) to form a wavelength conversion layer that achieves both thin thickness and high conversion efficiency. The composite material approach allows optimization of both absorption properties and structural integrity.
2Productivity
If quantum dot layer is placed close to micro LED for efficient light absorption, then light conversion efficiency improves, but thermal degradation occurs
Solution Approach 1:
The patent applies local quality by creating a spatially optimized structure where quantum dots are concentrated in specific regions with appropriate thickness distribution. This allows high absorption efficiency in the immediate vicinity of the LED while maintaining thermal stability through controlled distance and material selection in different zones.
Solution Approach 2:
The patent introduces matrix materials (resin, polymer, or glass) as intermediaries between the micro LED and quantum dots. These intermediary materials provide thermal isolation while maintaining optical coupling, resolving the contradiction between efficient light absorption and thermal protection.
3Reliability
If thick wavelength conversion layer is used to compensate for low absorption coefficient, then light absorption improves, but device thickness increases and structure becomes complex
Solution Approach 1:
The patent fundamentally changes the absorption parameter by using quantum dots with absorption coefficients 100-1000 times higher than conventional phosphors. This parameter change allows achieving the same absorption efficiency with layers 10-100 times thinner, eliminating the need for complex supporting structures.
4Reliability
If conventional phosphor materials are used, then wavelength conversion is achieved, but absorption coefficient is low requiring thick layers
Solution Approach 1:
The patent changes the fundamental optical parameter by transitioning from conventional phosphor materials to quantum dot materials, which exhibit size-tunable bandgap and extremely high absorption coefficients. This parameter change enables thin-layer wavelength conversion layers to achieve the same or better conversion efficiency than thick conventional phosphor layers.
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 provides a simpler structure with improved light emitting efficiency, reduced thickness, and enhanced color reproducibility, while maintaining high quantum efficiency and thermal stability, thus reducing costs and increasing productivity.
Implementation Method 1
a wavelength conversion layer which is stacked on the light emission surface of the first semiconductor layer... a semiconductor in a chalcopyrite-structure
Data Source
AI summary
A micro LED and a display module are provided. The micro LED includes a first semiconductor layer having a light emission surface and electronically connected to a first electrode; a second semiconductor layer electronically connected to a second electrode; an active layer disposed between the first and second semiconductor layers; and a wavelength conversion layer stacked on the light emission surface of the first semiconductor layer. The wavelength conversion layer is made of a semiconductor having a chalcopyrite-structure. The display module includes a plurality of such plurality of micro LEDs arranged in pixel units, which are electronically connected to a plurality of TFT electrodes. The module also includes a glass substrate and a TFT layer formed on one surface of the glass substrate, and the plurality of TFT electrodes are formed on the TFT layer. The resulting TFT layer does not require a color filter or a cover layer.