IPS Liquid Crystal Display with Optical Compensation for Oblique Viewing
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Solution Overview
Problem
Horizontal electric field mode liquid crystal display devices suffer from light leak and tint changes when viewed from an oblique direction due to the limitations in their structure, which affects the viewing angle and color shift during black display.
Innovation Solution
A liquid crystal display device configuration that includes a first polarizer, a first optical compensation layer, a liquid crystal cell, and a second polarizer, where the liquid crystal cell has electrodes forming an electric field parallel to the substrates, with specific retardation values for the optical compensation layers and a color filter to minimize light leak and tint changes during black display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an optically-anisotropic layer is added to compensate for color shift, then viewing angle performance is improved, but device complexity increases
Solution Approach 1:
The patent combines the optically-anisotropic layer with the protective film into a single integrated component. The protective film is configured to have both protective function and optical compensation function, eliminating the need for a separate optically-anisotropic layer while achieving color shift compensation and wide viewing angle performance.
Solution Approach 2:
The protective film is designed to serve multiple functions simultaneously: it protects the liquid crystal cell while also providing optical compensation for color shift. By making the protective film optically-anisotropic, it becomes a multi-functional component that addresses both protection and viewing angle requirements.
2Ease of manufacture
If the liquid crystal cell structure is simplified, then manufacturing ease is improved, but light leak and tint change occur at oblique viewing angles
Solution Approach 1:
The patent applies optical anisotropy locally to the protective film rather than changing the entire liquid crystal cell structure. By configuring only the protective film with specific optical properties (optically-anisotropic characteristics), it compensates for light leak and tint change at oblique angles while keeping the rest of the cell structure simple and easy to manufacture.
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 configuration significantly reduces light leak and tint changes when viewed from an oblique direction, enhancing the display performance by controlling the alignment and retardation of the liquid crystal molecules and optical compensation layers.
Implementation Method 1
liquid crystal molecules are allowed to respond in a substrate in-plane direction by an electric field including a component substantially parallel to a substrate surface
Implementation Method 2
liquid crystal layer being disposed between the pair of substrates and having controlled alignment
Implementation Method 3
an absorption axis of the first polarizer is parallel to a slow axis of the first optical compensation layer
Implementation Method 4
a liquid crystal display device comprising at least a first polarizer, a first optical compensation layer, a liquid crystal cell, and a second polarizer
Data Source
AI summary
Provided is a horizontal electric field mode liquid crystal display device in which light leak and tint change at the time of black display are reduced in case of being seen from an oblique direction. The liquid crystal display device is an IPS mode liquid crystal display device including at least a first polarizer, a first optical compensation layer, a liquid crystal cell, and a second polarizer in this order, in which the first optical compensation layer satisfies a predetermined relational expression, a total thickness-direction retardation Rth total(550) present between the liquid crystal layer and the second polarizer in the liquid crystal cell satisfies a predetermined relational expression, and a slow axis of the first optical compensation layer is parallel to an absorption axis of a polarizer layer.