Liquid Crystal Display Viewing Angle Compensators
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Solution Overview
Problem
Conventional liquid crystal displays face challenges in achieving high contrast and optical transmittance, especially at large viewing angles due to limitations in retardation values and the use of negative biaxial films, which can lead to reduced display visibility and color shifts.
Innovation Solution
A liquid crystal display configuration featuring first and second transparent substrates with a liquid crystal layer aligned vertically, two or three viewing angle compensators with specific retardation values, and polarizers oriented to optimize in-plane and thickness direction retardations, ensuring good display characteristics across various viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional liquid crystal display uses negative biaxial films for viewing angle compensation, then viewing angle characteristics are improved, but optical transmittance and contrast deteriorate at large observation angles
Solution Approach 1:
The patent changes the optical parameters of the liquid crystal layer by setting specific retardation values (300-940 nm) and using vertically aligned liquid crystal molecules, combined with viewing angle compensators having specific retardation ranges, to achieve high optical transmittance at large viewing angles while maintaining contrast
Solution Approach 2:
The patent uses a composite structure combining vertically aligned liquid crystal layer with viewing angle compensators (C plates) having negative uniaxial optical anisotropy, creating a multi-layer optical system that simultaneously achieves wide viewing angle compensation and high optical transmittance
2Illumination intensity
If the liquid crystal layer retardation is increased to maintain high contrast, then contrast is improved, but viewing angle characteristics deteriorate due to color shifts and reduced visibility
Solution Approach 1:
The patent optimizes the retardation parameter of the liquid crystal layer to be within 300-940 nm, which is a specific range that balances contrast and viewing angle characteristics, preventing color shifts while maintaining high contrast at large observation angles
Solution Approach 2:
The patent introduces viewing angle compensators (C plates) with negative uniaxial optical anisotropy at specific positions (between polarizers and glass substrates) to locally compensate for viewing angle dependencies, allowing the liquid crystal layer to maintain high contrast while the compensators correct viewing angle issues
3Adaptability or versatility
If negative biaxial films are used for viewing angle compensation, then right/left viewing is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces expensive negative biaxial films with viewing angle compensators (C plates) having negative uniaxial optical anisotropy, which are simpler and cheaper to manufacture while achieving the same viewing angle compensation effect for right/left viewing
Solution Approach 2:
The patent simplifies the optical compensation system by changing from biaxial to uniaxial optical anisotropy in the compensators, reducing the number of parameters that need to be controlled during manufacturing while maintaining effective viewing angle compensation
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
This configuration enhances viewing angle characteristics, maintaining high optical transmittance and contrast even at large observation angles, supporting high duty driving conditions without increasing manufacturing costs.
Implementation Method 1
liquid crystal molecules in a liquid crystal layer formed between two upper and lower glass substrates are vertically or approximately vertically aligned relative to a substrate surface
Implementation Method 2
a viewing angle compensator (C plate) having negative uniaxial optical anisotropy or a viewing angle compensator (negative biaxial film) having negative biaxial optical anisotropy is inserted
Implementation Method 3
the structure is known in which a vertical alignment mode (VA mode) liquid crystal cell is disposed between approximately crossed-Nichol disposed polarizers
Data Source
AI summary
A liquid crystal display includes: a liquid crystal layer squeezed between first and second transparent substrates and vertically aligned at a retardation of 300 nm or larger to 940 nm or smaller; two or three viewing angle compensators disposed on the first transparent substrate on the side opposite to the liquid crystal layer, each of the viewing angle compensators having a retardation of 90 nm or larger to 350 nm or smaller in a thickness direction and a retardation of 5 nm or larger to 30 nm or smaller in an in-plane direction; a first polarizer disposed on the two or three viewing angle compensator; and a second polarizer disposed on the second transparent substrate and crossed-Nichol disposed relative to the first polarizer, wherein an in-plane slow axis of each viewing angle compensator is disposed perpendicular to an absorption axis of the first polarizer.