Nano-Porous Quantum Dot Color Conversion Layer for Micro LED Displays
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Solution Overview
Problem
Existing display apparatus methods face challenges in achieving uniform color representation due to issues with indium concentration in micro light-emitting devices, color shift with temperature, and increased complexity in manufacturing processes.
Innovation Solution
A display apparatus featuring a micro light-emitting device emitting blue light and a color conversion layer with quantum dots, designed to minimize quenching and increase absorbance of blue light, is proposed. This includes a nano-porous layer with light blocking patterns and quantum dots impregnated in specific areas to convert blue light into red and green light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If quantum dots are dispersed in a transparent polymer to reduce nonradiative transfer, then nonradiative transfer is reduced, but light conversion efficiency is reduced because most blue light is not absorbed
Solution Approach 1:
The patent applies local quality by creating distinct regions with different optical properties: a first region with light blocking patterns and quantum dots for red light conversion, a second region with light blocking patterns and quantum dots for green light conversion, and a third region that transmits blue light. This spatial differentiation allows each region to optimize for its specific function, with quantum dots positioned where they can effectively absorb blue light while minimizing nonradiative transfer through controlled spacing.
Solution Approach 2:
The patent transitions from a two-dimensional dispersion of quantum dots in a polymer matrix to a three-dimensional structured arrangement with light blocking patterns at specific positions. By introducing the vertical dimension of light blocking patterns and creating separated first, second, and third regions, the patent enables more effective light management and quantum dot positioning to simultaneously reduce nonradiative transfer and improve light conversion efficiency.
2Quantity of substance
If the thickness of the color conversion layer is increased to increase absorbance of blue light, then absorbance increases, but image quality deteriorates and total thickness increases
Solution Approach 1:
The patent segments the color conversion layer into distinct first, second, and third regions with different functions. The first and second regions contain quantum dots for converting blue light to red and green light respectively, while the third region transmits blue light. This segmentation allows each region to be optimized for its specific purpose, achieving high absorbance in the conversion regions while maintaining image quality through the transmitted blue light region.
Solution Approach 2:
The patent incorporates a nano-porous layer between the light blocking patterns that contains the quantum dots. This porous structure increases the surface area and light interaction pathways, enhancing absorbance of blue light by the quantum dots without requiring a significant increase in the overall thickness of the color conversion layer, thereby maintaining image quality.
3Device complexity
If micro light-emitting devices emitting red, green, and blue light are located in sub-pixels, then color mixing is simplified, but uniformity is reduced due to difficulty in controlling indium concentration
Solution Approach 1:
The patent extracts the color conversion function from the micro light-emitting devices themselves and places it in a separate color conversion layer. Instead of relying on indium concentration control in the micro light-emitting devices to achieve different colors, the patent uses a single blue light-emitting micro light-emitting device combined with quantum dots in the color conversion layer to generate red and green light. This separates the light emission function from the color conversion function, eliminating the indium concentration uniformity problem.
4Illumination intensity
If a color filter array is used to convert white light into red, green, and blue light, then white light conversion is achieved, but about 2/3 of the total light is lost
Solution Approach 1:
The patent changes the mechanism of color conversion from absorption-based filtering to emission-based conversion. Instead of using color filter arrays that absorb unwanted wavelengths, the patent uses quantum dots that absorb blue light and emit red and green light at specific wavelengths. This parameter change from filtering to active conversion significantly reduces light loss while achieving the same color separation capability.
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 effectively minimizes quenching of quantum dots and enhances the absorbance of blue light, leading to improved color conversion efficiency and reduced light loss, thereby addressing the challenges of uniform color representation and manufacturing complexity.
Implementation Method 1
a color conversion layer with quantum dots, designed to minimize quenching and increase absorbance of blue light, is proposed. This includes a nano-porous layer with light blocking patterns and quantum dots impregnated in specific areas to convert blue light into red and green light.
Implementation Method 2
the color conversion layer including a red area in which the blue light is converted into the red light, a green area in which the blue light is converted into green light, and a blue area through which the blue light is transmitted
Data Source
AI summary
A display apparatus includes a driving substrate including a plurality of grooves, micro light-emitting devices provided in the plurality of grooves and configured to emit light of a first color, and a color conversion layer provided on the micro light-emitting devices and configured to convert the light of the first color into light of at least one second color, wherein the color conversion layer includes light blocking patterns spaced apart from the micro light-emitting devices and spaced apart from each other on a same plane, a nano-porous layer provided between adjacent ones of the light blocking patterns, spaced apart from the micro light-emitting devices, and including a plurality of nano-pores, and quantum dots impregnated in the nano-porous layer and configured to convert the light of the first color into the light of the at least one second color.