Wavelength Conversion Member with Light Scattering Layer
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Solution Overview
Problem
The existing wavelength conversion members in liquid crystal display devices suffer from insufficient brightness and scattering uniformity, poor stability of the wavelength conversion layer, and peeling issues between the barrier and wavelength conversion layers, leading to durability problems and brightness unevenness.
Innovation Solution
A wavelength conversion member is designed with a wavelength conversion layer interposed between two barrier layers, featuring a light scattering layer with specific binder and scattering particles, where one barrier layer is inorganic, and the thickness and refractive index ratios are optimized to enhance stability and peeling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If scattering particles are embedded in the QD phosphor material film layer, then light scattering function is provided, but brightness and scattering uniformity become insufficient
Solution Approach 1:
The patent divides the wavelength conversion member into distinct functional layers: a separate light scattering layer containing scattering particles is positioned adjacent to the QD phosphor material film layer. This segmentation allows each layer to perform its specific function optimally without interfering with the other, resolving the contradiction between providing light scattering function and maintaining brightness uniformity.
Solution Approach 2:
The patent introduces a barrier layer as an intermediary between the light scattering layer and the QD phosphor material film layer. This barrier layer prevents direct contact between scattering particles and quantum dots, avoiding the degradation of both scattering uniformity and quantum dot stability while still allowing the light scattering function to be effective.
2Illumination intensity
If scattering particles with high refractive index are used, then light scattering function is enhanced, but stability of wavelength conversion layer and peeling resistance deteriorate
Solution Approach 1:
The barrier layer serves as a mediator that separates the light scattering layer from the QD phosphor material film layer. This prevents direct interaction between high refractive index scattering particles and the quantum dots, maintaining the stability and peeling resistance of the wavelength conversion layer while still allowing the light scattering layer to provide enhanced light scattering function through the barrier layer.
3Reliability
If barrier layers are added to protect quantum dots, then stability improves, but peeling resistance between layers deteriorates
Solution Approach 1:
The patent specifies particular parameter ranges for the barrier layer including thickness (50-500 nm), refractive index (1.3-1.7), and material composition to optimize both protective function and adhesion. By carefully controlling these parameters, the barrier layer provides stability protection to quantum dots while maintaining sufficient peeling resistance through proper material selection and thickness optimization.
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
This configuration improves the stability and durability of the wavelength conversion layer, ensuring excellent brightness and scattering uniformity in image display devices by separating scattering particles and quantum dots into different layers and using a specific binder for improved peeling resistance.
Implementation Method 1
a light scattering layer which comprises a binder and scattering particles
Implementation Method 2
the quantum dots are excited to emit fluorescence. Here, by using quantum dots having different light emitting properties to emit various kinds of bright light including red light, green light, and blue light, white light can be realized
Data Source
AI summary
A wavelength conversion member, is provided with a wavelength conversion layer that includes quantum dots and is interposed between two barrier layers. The wavelength conversion member includes a light scattering layer that is provided between the barrier layers and the wavelength conversion layer, in which one of the barrier layers closest to the light scattering layer is formed of an inorganic component, the light scattering layer includes a binder, which is formed of either a compound having a hydrogen bonding functional group and a polymerizable group in a molecule or an organic metal coupling agent, and scattering particles having a diameter R of 0.2 to 5 μm, a thickness d of the light scattering layer is 0.2 to 4 μm, a thickness D of the wavelength conversion layer is 10 to 100 μm, and a ratio of d to D is 0.2% to 10%.