Reflective LCD Optical Axis Layout for Dark-State Color Stability
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Solution Overview
Problem
Reflective LCDs face issues with grayscale inversion and chromaticity performance variation due to liquid crystal layer thickness changes, particularly in the dark state.
Innovation Solution
A display device configuration with specific included angles between the liquid crystal optical axis, polarizing layer absorption axis, and compensation film optical axis, along with a front light module and electrode layers, to improve chromaticity performance and mitigate dark state color differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal layer is used in a reflective LCD, then the display can achieve reflective functionality, but the chromaticity performance in the dark state is significantly affected by thickness variation of the liquid crystal layer
Solution Approach 1:
A compensation film is introduced as an intermediary component between the liquid crystal layer and the polarizing layer. This compensation film has specific optical properties (retardation characteristics) that compensate for the thickness variations of the liquid crystal layer, thereby stabilizing the chromaticity performance in the dark state without requiring extremely precise thickness control of the liquid crystal layer.
Solution Approach 2:
The patent changes the optical parameters of the system by introducing a compensation film with specific retardation characteristics and optical axis orientation. By adjusting the retardation value and orientation angle of the compensation film, the system becomes less sensitive to liquid crystal layer thickness variations, thus improving chromaticity stability without demanding higher manufacturing precision.
2Reliability
If the liquid crystal layer thickness is controlled with high precision, then the chromaticity performance in the dark state improves, but the manufacturing complexity and cost increase
Solution Approach 1:
The compensation film acts as a mediator that decouples the relationship between liquid crystal layer thickness precision and chromaticity performance. By introducing this intermediate component with specific optical characteristics, the system achieves stable chromaticity performance even when the liquid crystal layer thickness has normal manufacturing variations, thereby reducing the required manufacturing precision without sacrificing display quality.
Solution Approach 2:
The patent modifies the optical parameter landscape by introducing a compensation film with specific retardation and orientation characteristics. This parameter change allows the system to achieve chromaticity stability through the compensation film's properties rather than relying solely on precise liquid crystal layer thickness control, thus reducing manufacturing complexity while maintaining or improving chromaticity performance.
3Reliability
If a compensation film is introduced to improve chromaticity performance, then the dark state color difference is reduced, but the device structure becomes more complex
Solution Approach 1:
The compensation film is positioned as an intermediary layer between the liquid crystal layer and the polarizing layer. This strategic placement allows the compensation film to address dark state color consistency issues without requiring a complete redesign of the display structure. The film integrates into the existing layer sequence, providing functional improvement with minimal structural disruption.
Solution Approach 2:
The patent optimizes the optical parameters of the compensation film (retardation value, optical axis orientation angle) to achieve the desired chromaticity performance. By carefully selecting these parameters, the system improves dark state color consistency while keeping the compensation film's physical and optical characteristics within manageable ranges, thus balancing performance improvement with structural simplicity.
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
Enhances chromaticity performance in the dark state and reduces color differences caused by liquid crystal layer thickness variations, ensuring consistent display quality.
Implementation Method 1
The liquid crystal layer is disposed between the pixel array substrate and the color filter substrate, and has a liquid crystal optical axis
Implementation Method 2
The polarizing layer is disposed on the color filter substrate, and has an absorption axis
Implementation Method 3
The compensation film is disposed between the polarizing layer and the liquid crystal layer, and has a compensation film optical axis
Data Source
AI summary
A display device includes a pixel array substrate, a color filter substrate, a liquid crystal layer, a polarizing layer, and a compensation film. The color filter substrate is disposed to overlap the pixel array substrate. The liquid crystal layer is disposed between the pixel array substrate and the color filter substrate, and has a liquid crystal optical axis. The polarizing layer is disposed on the color filter substrate, and has an absorption axis. The compensation film is disposed between the polarizing layer and the liquid crystal layer, and has a compensation film optical axis. A first included angle between the liquid crystal optical axis and the compensation film optical axis is within a range between 62.5 degrees to 65 degrees. A second included angle between the absorption axis and the liquid crystal optical axis is within a range between 80 degrees to 85 degrees or 5 degrees to 10 degrees.