Liquid Crystal Compensation Layers to Reduce Side-View Light Leakage
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Solution Overview
Problem
The side-view contrast ratio of current vertical alignment liquid crystal display devices is not well due to side-view light leakage in the dark state, which is exacerbated by the limitations of conventional compensation films that adjust compensation values through stretching, failing to match the phase difference of the liquid crystal display panel.
Innovation Solution
A display device is designed with liquid crystal compensation layers on both polarizers, adjusting compensation values through refractive index difference and thickness of liquid crystal molecules rather than stretching, to improve the dark state side-view light leakage and contrast ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional compensation film is used to compensate for birefringence, then light leakage is reduced within a certain viewing angle range, but the compensation value is limited and cannot match the phase difference of the vertical alignment liquid crystal display device
Solution Approach 1:
The patent changes the fundamental parameter of compensation from mechanical stretching (limited range) to liquid crystal molecular orientation (tunable range). By controlling the orientation of liquid crystal molecules in the compensation layer through rubbing or magnetic field application, the compensation value can be continuously adjusted to precisely match the phase difference of the vertical alignment liquid crystal display device across wide viewing angles.
Solution Approach 2:
The patent replaces the mechanical stretching system of conventional films with a liquid crystal molecular orientation system. Instead of physically deforming a film to achieve compensation, the invention uses the optical anisotropy of liquid crystal molecules whose orientation can be controlled by external fields or surface treatment, providing a more flexible and adaptable compensation mechanism.
2Area of stationary object
If the viewing angle of the liquid crystal display device is increased, then the coverage area is improved, but the contrast ratio of images decreases
Solution Approach 1:
The patent applies different properties to different parts of the optical path by introducing a compensation layer with specific liquid crystal molecular orientation between the polarizer and the liquid crystal display panel. This local compensation structure addresses the viewing angle-dependent contrast ratio issue by providing position-specific optical compensation that maintains high contrast across wide viewing angles while preserving the wide viewing angle coverage of the display device.
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 effectively reduces dark state side-view light leakage and enhances the contrast ratio and image quality by compensating for birefringence of liquid crystal molecules, providing a comprehensive compensation effect with liquid crystal compensation layers on both sides of the panel.
Implementation Method 1
the birefringence of the liquid crystal molecules in the liquid crystal layer changes with observation angles
Implementation Method 2
The principle of the compensation film is to compensate the phase differences generated by the liquid crystals at different viewing angles
Implementation Method 3
adjusting the refractive index difference and thickness of the liquid crystal molecules
Data Source
AI summary
A display device is provided. In the present application, a liquid crystal compensation layer is provided on both first polarizer and second polarizer, and an improvement of compensation value is not realized by stretching the liquid crystal compensation layer but by adjusting the refractive index difference and thickness of the liquid crystal molecules, so the adjustment range is large, the restriction is small, and it can be matched with the high phase difference of the liquid crystal display panel. Therefore, the dark state side-view light leakage of the liquid crystal display panel and the contrast ratio of the liquid crystal display panel are improved, and the image quality is enhanced.