Color Display Device Using White Light Emission and Quantum Dot Filters
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Solution Overview
Problem
Current OLED color display technologies face challenges with low productivity, high costs, and color shifting due to the need for precise mask alignment and differences in lifespan and excitability among primary colors, while existing solutions like white light plus RGB filters suffer from low efficiency due to optical energy absorption.
Innovation Solution
A color display device utilizing a white light emission layer and a color change layer with quantum dot materials in a blue, green, and red sub-pixel zone, eliminating the need for fine metal masks and allowing for simpler manufacturing, reduced costs, and improved color purity through thermal evaporation and quantum dot filter layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If RGB primary color emission technique is used, then color display capability is achieved, but manufacturing complexity and cost increase due to high precision mask alignment requirements
Solution Approach 1:
The patent extracts the color filtering function from the emission process itself and places it in a separate color filter layer. Instead of requiring each sub-pixel to emit its primary color directly (which requires precise mask alignment), the invention uses a white light emission layer combined with a color filter layer containing quantum dots that passively filter the white light to produce the desired colors. This separation of emission and filtering functions eliminates the need for high precision mask alignment during the emission layer fabrication.
2Ease of manufacture
If white light plus RGB filter technique is used, then manufacturing complexity is reduced, but light efficiency decreases due to optical energy absorption
Solution Approach 1:
The patent employs quantum dot materials with specific size-controlled bandgaps to create a composite color filter layer. These quantum dots are embedded in a matrix material, forming a composite structure where the quantum dots selectively absorb specific wavelengths of white light and re-emit them at desired wavelengths. This composite material approach reduces energy loss compared to conventional organic dyes while maintaining manufacturing simplicity.
3Ease of manufacture
If conventional color filter materials are used, then manufacturing is simplified, but color purity is reduced
Solution Approach 1:
The patent utilizes the size-dependent optical properties of quantum dots, where changing the particle size directly changes the absorption and emission wavelengths. By precisely controlling the quantum dot size during synthesis (a parameter change in the material fabrication process), the invention achieves high color purity in the filter layers while maintaining relatively simple manufacturing procedures. Different sized quantum dots produce different colors, enabling precise color control without complex manufacturing.
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 achieves high color purity, reduced thickness, and lower power consumption, with the white sub-pixel zone saving manufacturing costs and enabling flexible, ultra-thin, and transparent displays on various substrates.
Implementation Method 1
a white light emission layer formed on the hole transporting layer, an electron transporting layer formed on the white light emission layer... wherein the white light emission layer emits white light
Implementation Method 2
Inorganic quantum dot possesses advantages, such as photoluminescence, stable performance, long lifespan, wide absorption spectrum, and good color purity... the blue sub-pixel zone comprising a blue light filter layer formed therein, the green sub-pixel zone comprising a green light filter layer or a green light change layer formed therein, the red sub-pixel zone comprising a red light filter layer or a red light change layer formed therein
Data Source
AI summary
The present invention provides a color display device, including a substrate, an anode formed on the substrate, a TFT array formed on the anode, a hole injection layer formed on the TFT array, a hole transporting layer formed on the hole injection layer, a white light emission layer formed on the hole transporting layer, an electron transporting layer formed on the white light emission layer, a cathode formed on the electron transporting layer, a cover plate disposed above the cathode and bonded to the substrate, a color change layer formed on an inside surface of the cover plate, and a sealing enclosure resin bonding the substrate and the cover plate together, wherein the color change layer includes a blue sub-pixel zone, a green sub-pixel zone, a red sub-pixel zone, and a white sub-pixel zone that are spaced from each other, the blue sub-pixel zone including a blue light filter layer formed therein, the green sub-pixel zone including a green light filter layer or a green light change layer formed therein, the red sub-pixel zone including a red light filter layer or a red light change layer formed therein, the white sub-pixel zone comprising no filter layer formed therein.