Light Conversion Device Using Segmented Fluorescent Films
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Solution Overview
Problem
Existing light conversion devices face challenges in achieving excellent durability and conversion efficiency, particularly with organic fluorescent dyes, which are prone to instability under heat and light, and nanocrystal fluorescent substances are costly and vulnerable to heat and oxygen.
Innovation Solution
A light conversion device comprising a first and second light conversion film with organic fluorescent dyes, where the maximum emission wavelength of the second film is smaller than the first, and a barrier film to prevent moisture and oxygen ingress, enhancing light conversion efficiency and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the concentration of organic fluorescent dye is increased to increase conversion efficiency and intensity of converted light, then conversion efficiency is improved, but extinction phenomenon occurs and stability against heat or light is deteriorated
Solution Approach 1:
The patent divides the light conversion function into multiple layers with different organic fluorescent dyes having different emission wavelengths. Each layer operates at optimized dye concentrations without causing extinction phenomena, while collectively achieving high overall conversion efficiency. This segmentation allows each layer to maintain stability while contributing to high productivity.
Solution Approach 2:
Different regions (layers) of the light conversion device use different organic fluorescent dyes with specific emission characteristics optimized for their local function. Each layer is designed with appropriate dye concentration and composition tailored to its specific wavelength conversion requirement, allowing high conversion efficiency in each local region without suffering from extinction phenomena.
2Productivity
If nanocrystal fluorescent substance is used to achieve high quantum efficiency and strong fluorescence, then conversion efficiency is improved, but price competitiveness is difficult to secure and vulnerability to heat and oxygen increases
Solution Approach 1:
The patent replaces expensive nanocrystal fluorescent substances with organic fluorescent dyes that are significantly cheaper and can be easily replaced or renewed. While individual organic dyes may have shorter operational lifetimes than nanocrystals, the overall system achieves cost-effectiveness and maintains performance through the multi-layer design that protects against degradation.
Solution Approach 2:
The patent uses composite structures combining multiple organic fluorescent dyes in different layers, each selected for specific wavelength conversion properties. This composite approach achieves high quantum efficiency comparable to nanocrystals while avoiding their vulnerability to heat and oxygen, as the organic dye composite system can be designed with appropriate encapsulation and stabilization.
3Reliability
If inorganic fluorescent substance is used to achieve excellent physical and chemical stability and high color purity, then reliability is improved, but emission efficiency is low and development of fluorescent substances excited in near ultraviolet or blue region is limited
Solution Approach 1:
The patent changes the fundamental parameter of fluorescent material type from inorganic to organic, enabling excitation in the near ultraviolet or blue region with high emission efficiency. By carefully selecting organic fluorescent dyes with appropriate absorption and emission characteristics for each layer, the system achieves both high productivity and maintained reliability through the stable polymer matrix encapsulation.
4Device complexity
If a single light conversion film is used to simplify device structure, then device complexity is reduced, but conversion efficiency and color purity are insufficient
Solution Approach 1:
The patent segments the light conversion function into multiple layers, each responsible for specific wavelength conversions. This segmentation achieves high overall conversion efficiency and color purity by dividing the broad spectrum conversion task into specialized layers, while still maintaining relatively simple device structure through the straightforward layered architecture.
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 device improves color purity and reproducibility by converting light into white light, maintaining emission characteristics and extending the lifespan of the light conversion film by preventing external damage.
Implementation Method 1
The fluorescent substance absorbs a part of a specific wavelength of the light emitted from the light source and converts and emits the part of the light into light having a longer wavelength in a visible light region
Implementation Method 2
a barrier film provided on one surface of the light conversion film or on the other surface of the transparent substrate, to prevent external moisture or oxygen from penetrating into the light conversion film
Data Source
AI summary
This application relates to a light conversion device and a display device.