In-Plane Switching LCD Optical Compensation Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In-plane switching liquid crystal display (IPS-LCD) devices experience light leakage in the black state, leading to a lowered contrast ratio due to the orthogonality of polarizers being broken at various viewing angles, which affects the viewing angle and color shift.
Innovation Solution
The implementation of a liquid crystal display panel with first and second polarizers, each having protective and polarizing films, and optical compensation films with specific refractive index properties to control light leakage and polarization states, including a +C plate and an A plate to manage phase retardation and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If orthogonally arranged polarizers are used in IPS-LCD to achieve wide viewing angles, then viewing angle is improved, but light leakage occurs at diagonal directions causing lowered contrast ratio
Solution Approach 1:
Optical compensation films are introduced as intermediary elements between the polarizers and the liquid crystal layer. These compensation films have specific refractive index properties that mediate the optical path differences caused by oblique viewing angles, preventing light leakage while preserving the wide viewing angle capability of the orthogonal polarizer arrangement.
Solution Approach 2:
The refractive indices of the optical compensation films are specifically designed and adjusted to match and compensate for the optical anisotropy of the liquid crystal layer at different viewing angles. By changing the refractive index parameters of the compensation films, the optical path differences are corrected, eliminating light leakage at diagonal directions while maintaining the orthogonal polarizer configuration.
2Object-generated harmful factors
If optical compensation films with specific refractive index properties are added to reduce light leakage, then contrast ratio is improved, but device complexity increases
Solution Approach 1:
The optical compensation films are applied selectively in specific regions where light leakage occurs, particularly at diagonal viewing angles. Rather than uniformly complicating the entire display structure, the compensation films are positioned to address local optical path differences, thereby reducing light leakage without unnecessarily increasing overall device complexity.
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 significantly reduces light leakage at diagonal directions, thereby improving the contrast ratio and minimizing color shift, enhancing the viewing angles and overall display performance.
Implementation Method 1
optical compensation films with specific refractive index properties to control light leakage and polarization states, including a +C plate and an A plate to manage phase retardation and alignment
Implementation Method 2
first and second polarizers, each having protective and polarizing films
Data Source
AI summary
An in-plane switching liquid crystal display device includes a liquid crystal display panel having first and second substrates, a first polarizer disposed at a first surface of the liquid crystal display panel and having a first protective film, a first polarizing film, and a second protective film, a second polarizer disposed at a second surface of the liquid crystal display panel and having a third protective film, a second polarizing film, and a fourth protective film, and a first optical compensation film between the first polarizer and the liquid crystal display panel, the third protective film being adjacent to the liquid crystal display panel and having a substantially zero retardation value.