Overlapping Pixel Electrodes for High Contrast LCD Light Source
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Solution Overview
Problem
Liquid crystal display devices have a low contrast ratio compared to OLED displays, which limits their ability to display high dynamic range images effectively, as they cannot achieve the required contrast ratio of dozens of thousands to one.
Innovation Solution
A light source device for a display device is proposed, comprising a planar light source and a monochrome liquid crystal panel with overlapping pixel electrodes, which enhances the contrast ratio by controlling light transmission and reducing the black level, allowing for improved display of high dynamic range images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional liquid crystal display device is used, then the device structure is simple, but the contrast ratio is low (about 2000:1 at most)
Solution Approach 1:
The invention divides the pixel electrode into multiple sub-pixel electrodes (first, second, third, and fourth sub-pixel electrodes) within each pixel region. This segmentation allows independent control of light transmission for different color components, enabling precise grayscale control and significantly improving the contrast ratio while maintaining a single liquid crystal panel structure.
Solution Approach 2:
Different regions of the pixel electrode are assigned different functions: the first and second sub-pixel electrodes control one color component, while the third and fourth sub-pixel electrodes control another color component. This local differentiation enables precise control of light transmission characteristics in different areas, achieving high contrast ratio and accurate color reproduction.
2Illumination intensity
If multiple liquid crystal panels are stacked to improve contrast ratio, then the contrast ratio increases, but the device complexity and black level control difficulty increase
Solution Approach 1:
Instead of stacking multiple panels, the invention segments the pixel electrode into multiple sub-pixel electrodes within a single panel. This approach achieves high contrast ratio improvement without the complexity of multi-panel stacking, while also simplifying black level control since all sub-pixel electrodes are controlled within one panel structure.
3Illumination intensity
If pixel electrodes are made larger to improve light transmission, then the brightness increases, but the overlap region between adjacent pixels increases causing color contamination
Solution Approach 1:
The invention assigns different control functions to different sub-pixel electrodes. The first and second sub-pixel electrodes control one color component while the third and fourth control another color component. This local quality differentiation allows the overlap regions to be controlled independently, preventing color contamination while maintaining large electrode areas for high brightness.
Solution Approach 2:
The invention dynamically controls the voltage applied to different sub-pixel electrodes to achieve desired grayscale levels. By independently adjusting the voltage on each sub-pixel electrode, the system can control the liquid crystal orientation in overlap regions to prevent color contamination while maintaining high light transmission in exclusive regions.
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 increases the contrast ratio of liquid crystal display devices, enabling them to display high dynamic range images with improved brightness and color accuracy, comparable to OLED displays.
Implementation Method 1
a liquid crystal panel (131, 132) including a liquid crystal layer (211) between the two substrates (200, 250)
Implementation Method 2
Each pixel electrode (203) and common electrode (204) apply an electric field to the liquid crystal (211)
Data Source
AI summary
A light source device for a display device includes a planar light source and a monochrome liquid crystal panel. The monochrome liquid crystal panel includes a plurality of pixel electrodes. Pixel electrodes adjacent to each other in the plurality of pixel electrodes partially overlap each other within one pixel. The monochrome liquid crystal panel includes an exclusive region including a part of one of the plurality of pixel electrodes but not including the other pixel electrodes and an overlap region including parts of pixel electrodes adjacent to each other.