Stacked Liquid Crystal Display Light Diffusion Layer Moire Reduction
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Solution Overview
Problem
Stacked liquid crystal displays experience significant moire pattern occurrences, leading to degraded display quality, particularly when two panels are combined, and existing methods to improve contrast often result in technical issues such as poor reliability and response properties.
Innovation Solution
Incorporating a light diffusion layer with a haze value of 50% or greater in at least one of the liquid crystal panels, either on the display plane side or between the panels, to mitigate moire patterns and improve contrast by reducing mutual interference between fine structures, and using polarized light absorbing layers to form crossed Nicols for enhanced shutter performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two liquid crystal panels are stacked to improve contrast ratio, then contrast ratio increases to three to four digit values, but moire pattern occurrences increase significantly degrading display quality
Solution Approach 1:
An optical compensation film is introduced as an intermediary layer between the two liquid crystal panels. This film compensates for the optical path differences and interferes with the formation of moire patterns by adjusting the polarization state and optical phase of light passing through the stacked panels, thereby maintaining high contrast ratio while eliminating display quality degradation.
2Manufacturing precision
If pigment content or cell thickness is increased to improve light absorption by dichroic pigment, then contrast is improved, but reliability and response properties deteriorate
Solution Approach 1:
The invention changes the optical parameters of the system by introducing an optical compensation film with specific retardation characteristics. Instead of increasing pigment content or cell thickness, the film modifies the optical path and polarization state to enhance light absorption efficiency of the dichroic pigment, thereby improving contrast while maintaining acceptable reliability and response properties.
3Manufacturing precision
If optical compensation is performed to improve contrast ratio from 8 to 100, then contrast ratio increases, but absolute contrast ratio remains lower than stacked panel solutions
Solution Approach 1:
The invention creates a composite optical system combining two liquid crystal panels with different liquid crystal materials and an optical compensation film. This composite structure leverages the complementary optical properties of the different liquid crystal materials and the compensation film to achieve synergistic effect, producing a contrast ratio that exceeds the sum of individual panel performances.
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 moire pattern occurrences and improves contrast by smudging periodic information from fine structures, resulting in higher display quality and reduced contrast deterioration, while maintaining mechanical strength and cost-effectiveness.
Implementation Method 1
a light diffusion layer having a light diffusing property... to mitigate moire patterns and improve contrast by reducing mutual interference between fine structures
Implementation Method 2
using polarized light absorbing layers to form crossed Nicols for enhanced shutter performance
Data Source
AI summary
A liquid crystal display of the present invention contains a first panel and a second panel being stacked. Adjacent pairs of polarizers (A to C) disposed on the panels form crossed Nicols. When the first panel produces a display according to a first display signal, the second panel produces a display according to a second display signal obtained from the first display signal. Each of the two joined panels is provided with a light diffusion layer having a light diffusing property. The provision of the light diffusion layers enables reducing moire pattern occurrences which would otherwise markedly increase when two liquid crystal panels are stacked. As a result, the liquid crystal display has high display quality.