Color Conversion Sheet with Dual Organic Layers for High Purity White Light
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Solution Overview
Problem
Current color conversion methods for liquid crystal displays and lighting apparatuses face challenges in achieving both high color reproducibility and luminance, with existing techniques using quantum dots being durable but limited by heat and chemical sensitivity, and organic light-emitting materials falling short in improving both color gamut and luminance simultaneously.
Innovation Solution
A color conversion sheet comprising two layers with specific organic light-emitting materials and binder resins, where one layer emits light in the green spectrum and the other in the red spectrum, optimized to reduce spectral overlap and enhance color purity, using compounds represented by General Formula (1) to achieve high emission quantum yield and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If quantum dots are used as color conversion material, then color purity and color reproducibility are improved, but durability deteriorates due to vulnerability to heat, water, and oxygen
Solution Approach 1:
The patent replaces quantum dots with organic light-emitting materials that have shorter operational lifetimes but can be easily replaced and are less sensitive to environmental degradation. The organic materials are encapsulated in protective layers to extend their service life while maintaining ease of replacement.
Solution Approach 2:
The patent uses composite structures combining organic light-emitting materials with protective encapsulation layers and binder resins. This composite approach provides both the color conversion functionality and environmental protection, resolving the durability issue while maintaining color purity.
2Reliability
If organic light-emitting materials are used as color conversion material, then durability is improved, but color purity and luminance are insufficient
Solution Approach 1:
The patent optimizes parameters including the chemical structure of organic light-emitting materials, their concentration in the color conversion layer, and the thickness of the layer to achieve both high color purity and high luminance while maintaining durability.
Solution Approach 2:
The patent creates different regions with different organic light-emitting materials optimized for specific color ranges (blue, green, red). Each region is locally optimized for its specific function while contributing to the overall performance of the display device.
3Reliability
If organic light-emitting materials are used as color conversion material, then durability is improved, but luminance is insufficient
Solution Approach 1:
The patent combines multiple organic light-emitting materials with different emission characteristics in the color conversion layer to achieve both high luminance and high color purity. The synergistic effect of combined materials overcomes the limitations of individual materials.
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 enables the production of white light with high color purity and a large color gamut, improving color reproducibility and luminance in displays and lighting applications, while maintaining durability and reducing material costs.
Implementation Method 1
Color conversion means converting light emission from a light-emitting body into light with a longer wavelength and means converting blue light emission into green or red light emission, for example
Data Source
AI summary
A color conversion sheet that converts incident light into light with a wavelength longer than that of the incident light, the color conversion sheet including the following layer (A) and layer (B): the layer (A): a layer containing an organic light-emitting material (a) that exhibits light emission with a peak wavelength observed in a region of 500 nm or more and 580 nm or less by using excitation light in a wavelength range of 400 nm or more and 500 nm or less, and a binder resin; and the layer (B): a layer containing an organic light-emitting material (b) that exhibits light emission with a peak wavelength observed in a region of 580 nm or more and 750 nm or less by being excited by either or both of excitation light in a wavelength range of 400 nm or more and 500 nm or less and light emission from the organic light-emitting material (a), and a binder resin; wherein SPA>SPB where SP values as solubility parameters of the binder resin contained in the layer (A) and the binder resin contained in the layer (B) are SPA (cal/cm3)0.5 and SPB (cal/cm3)0.5, respectively.