Color Substrate with Retroreflective Layer for Display Light Efficiency
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Solution Overview
Problem
Liquid crystal display devices face challenges with low light efficiency and reduced color reproducibility due to the use of color filters, which result in light intensity reduction and color mixing issues, especially when using reflective or light-absorbing black matrices.
Innovation Solution
A color substrate with separate pixel regions, light shielding regions, and quantum dot-based color conversion layers, along with a retroreflective layer to enhance light efficiency and prevent color mixing, is introduced. The substrate includes first and second color conversion layers that convert incident light into specific color lights, and a retroreflective layer that retroreflects light to improve light utilization and reduce color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If color filters are used in liquid crystal display devices, then color reproduction is achieved, but light intensity is reduced by about 1/3 at each color filter
Solution Approach 1:
The patent extracts the color conversion function from traditional color filters and relocates it to a dedicated color conversion layer positioned between the backlight unit and liquid crystal layer. This separation allows the color filters to be removed entirely, eliminating their light absorption effect while preserving color reproduction through quantum dot-based conversion of blue light to red and green wavelengths.
Solution Approach 2:
The patent introduces a color conversion layer as an intermediary component that converts blue light from the backlight into red and green light. This intermediary layer replaces the function of multiple color filters, achieving color reproduction with significantly higher light transmission efficiency since the conversion process does not absorb light in the same way filters do.
2Object-affected harmful factors
If a reflective black matrix is used, then color mixing between adjacent pixels is prevented, but light emitted by color conversion layers is reflected and irradiated onto adjacent pixels causing color mixing
Solution Approach 1:
The patent removes the black matrix component entirely from the display structure. Instead of using a reflective or absorptive black matrix at the edges of pixels, the invention relies on the inherent light shielding properties of the pixel electrode structures and the positioning of color conversion layers to prevent color mixing, thereby eliminating the need for additional light-blocking or reflecting elements.
Solution Approach 2:
Rather than using a reflective black matrix that reflects light onto adjacent pixels (causing color mixing), the patent inverts the approach by using light-absorbing pixel electrode structures and strategic positioning to absorb or block light before it can reach adjacent pixels. This inversion of the reflection principle eliminates the harmful reflective effect.
3Object-affected harmful factors
If a light-absorbing black matrix is used, then color mixing is reduced, but light efficiency is reduced when light emitted by color conversion layers is absorbed
Solution Approach 1:
The patent extracts and removes the black matrix component from the display structure. Color mixing prevention is achieved through alternative means: the pixel electrode structures, the positioning of color conversion layers over pixel regions, and the use of light-shielding sidewalls, eliminating the need for light-absorbing black matrix material that would reduce overall light efficiency.
Solution Approach 2:
The patent introduces light-shielding sidewalls as intermediary structures positioned between adjacent pixel regions. These sidewalls prevent light from escaping one pixel region and entering another, providing color isolation without requiring a continuous light-absorbing black matrix layer that would absorb useful light and reduce efficiency.
4Loss of energy
If quantum dot color conversion layers are used instead of color filters, then light efficiency is improved, but color mixing occurs when light is emitted in various directions
Solution Approach 1:
The patent segments the display into distinct pixel regions with light-shielding boundaries (sidewalls and spacing) that prevent light emitted by quantum dot color conversion layers in one region from reaching adjacent regions. This segmentation maintains the high light efficiency of quantum dots while preventing color mixing through spatial isolation of light paths.
Solution Approach 2:
The patent introduces light-shielding sidewalls and spacing structures as intermediary elements between adjacent pixel regions. These intermediaries block or absorb light that escapes the primary emission direction of quantum dots, preventing it from reaching adjacent pixels and causing color mixing, while allowing the quantum dots to maintain their high conversion efficiency.
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 significantly enhances light efficiency and color reproducibility by minimizing light loss and color mixing, allowing for improved display performance with increased light transmission and reduced absorption, thereby enhancing the overall display quality.
Implementation Method 1
a first color conversion layer over the first pixel region and configured to convert incident light into a first color light, a second color conversion layer over the second pixel region and configured to convert the incident light into a second color light
Implementation Method 2
a retroreflective layer over the light shielding region and configured to retroreflect light incident from the first and second color conversion layer
Data Source
AI summary
A color substrate and a display device including the same. The color substrate includes: a substrate including first and second pixel regions spaced apart from each other, and a light shielding region between the first and second pixel regions; a first color conversion layer over the first pixel region and configured to convert incident light into first color light; a second color conversion layer over the second pixel region and configured to convert the incident light into second color light; and a retroreflective layer over the light shielding region and configured to retroreflect incident light through the first and second color conversion layer.