Liquid Crystal Panel Compensation Structure for Viewing Angle Light Leakage
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Solution Overview
Problem
Conventional liquid crystal display panels experience significant light leakage and reduced contrast and definition at large viewing angles due to birefringence variations, particularly in the horizontal viewing angles, which affect the overall viewing effect.
Innovation Solution
A liquid crystal panel compensation structure comprising two second uniaxial compensation films and one first biaxial compensation film, with specific compensation values and refractive index settings, is used to reduce light leakage and enhance contrast and definition at large viewing angles for panels with optical path differences between 324.8 and 361.4 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional optical compensation films are used, then the viewing angle is increased, but light leakage occurs and contrast decreases at large viewing angles
Solution Approach 1:
The patent divides the compensation structure into three separate compensation films with different optical properties. The first compensation film has a positive uniaxial refractive index, the second has a negative uniaxial refractive index, and the third has a negative biaxial refractive index. Each film segment addresses specific viewing angle issues, collectively reducing light leakage while maintaining wide viewing angles.
Solution Approach 2:
The patent employs a composite compensation structure combining three different types of compensation films with distinct optical characteristics. By stacking films with positive uniaxial, negative uniaxial, and negative biaxial refractive indices, the system creates a composite optical compensation mechanism that simultaneously achieves wide viewing angles and minimal light leakage.
2Adaptability or versatility
If conventional optical compensation films are used, then the viewing angle is increased, but contrast and definition decrease at large viewing angles
Solution Approach 1:
The compensation structure is segmented into three specialized films, each contributing to different aspects of image quality. The first film (positive uniaxial) addresses brightness uniformity, the second film (negative uniaxial) controls contrast, and the third film (negative biaxial) maintains definition. This segmentation allows each film to optimize specific parameters while achieving wide viewing angles collectively.
Solution Approach 2:
The composite structure of three compensation films with different optical signs and axes creates synergistic effects. The combination of positive uniaxial, negative uniaxial, and negative biaxial films produces a composite compensation effect that preserves contrast and definition across wide viewing angles, overcoming the limitations of single-film or two-film structures.
3Measurement precision
If the optical path difference is increased to improve image quality, then the phase retardation is enhanced, but the viewing angle performance deteriorates
Solution Approach 1:
The patent optimizes the optical path difference parameters of each compensation film individually and collectively. By carefully selecting the thickness and refractive index of each film, the system achieves a balanced total optical path difference that provides sufficient phase retardation for image quality while maintaining wide viewing angle performance through the distributed compensation approach.
Solution Approach 2:
Instead of using a single thick compensation film with high optical path difference, the patent segments the total compensation into three thinner films with lower individual optical path differences. This segmentation distributes the phase retardation across multiple layers, each contributing to the overall image quality while maintaining better viewing angle characteristics than a single high-OPTD film would provide.
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 proposed compensation structure effectively reduces light leakage in the dark state and improves contrast and definition at large viewing angles, enhancing the visual range and image quality by optimizing the compensation values of the films.
Implementation Method 1
The nematic liquid crystal is a substance having birefringence Δn. The light passing through the liquid crystal molecule is divided into an ordinary ray and an extraordinary ray. If the light is obliquely incident into the liquid crystal molecule, two refracted light would be generated. The birefringence of the light is Δn=ne−no
Implementation Method 2
after the light passing through the liquid crystal clamped between the top and bottom glasses, a phase retardation would be occurred on the light. The light characteristic of a liquid crystal cell is measured by the phase retardation Δn·d, which is so called as optical path difference
Implementation Method 3
If the light is obliquely incident into the liquid crystal molecule, two refracted light would be generated. The birefringence of the light is Δn=ne−no, wherein ne represents the refractive index of the liquid crystal molecule for the ordinary ray, and no represents the refractive index of the liquid crystal molecule for the extraordinary ray
Data Source
AI summary
The present invention provides a liquid crystal panel compensation structure comprising two second compensation film disposed at two sides of a liquid crystal panel and a first compensation film disposed above one of the second compensation film; a liquid crystal layer comprising a plurality of liquid crystal molecules being disposed in the liquid crystal panel, a refractive index anisotropy of the liquid crystal layer being Δn, a depth of the liquid crystal layer being d, and a pretilt angle of the liquid crystal molecules being θ; the first compensation film being a biaxial compensation film, an in-plane compensation value thereof being Ro1, and a depth compensation value thereof being Rth1; each of the second compensation film being an uniaxial compensation film, and the depth compensation value thereof being Rth2, wherein 342.8 nm≦Δn·d≦361.4 nm, 85°≦θ<90°, 52 nm≦Ro1≦78 nm, 196 nm≦Rth1≦293 nm, Y1 nm≦Rth2≦Y2 nm, Y1=−0.50645·Rth1+164.1, and Y2=−0.003085·(Rth1)2+0.932·Rth1+23.7. The present invention further provides a liquid crystal display apparatus comprising the compensation structure described above.