IPS Liquid Crystal Display Optical Compensation for Oblique Viewing
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Solution Overview
Problem
In-plane switching (IPS) mode liquid crystal display devices experience brightness increase and coloring when viewed obliquely during black display due to light leakage and wavelength dispersion, which are not adequately addressed by existing technologies.
Innovation Solution
The implementation of a liquid crystal display device configuration that includes a first and second polarizing layer with absorption axes perpendicular to each other, a homogeneously aligned liquid crystal layer, a matrix-drive electrode group, a rear-surface illuminating device, at least one optical compensating member, and a color filter layer with different thickness-direction retardations for red, green, and blue pixels, where the optical compensating members are strategically placed between the polarizing layers and the liquid crystal layer to reduce light leakage and coloring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single retardation film is positioned inside one polarizer to improve viewing angle, then polarizer viewing angle is improved, but black display characteristics at oblique angles are not sufficiently improved and coloring due to wavelength dispersion is not reduced
Solution Approach 1:
The invention divides the optical compensation function into two separate components: a first retardation film positioned inside the first polarizer and a second retardation film positioned inside the second polarizer. This segmentation allows each retardation film to independently compensate for viewing angle dependence and wavelength dispersion effects, achieving superior black display characteristics and color accuracy at oblique viewing angles compared to using a single retardation film.
2Adaptability or versatility
If the absorption axis of the first polarizing layer and the optical axis of the liquid crystal layer are made substantially perpendicular to each other, then one configuration is achieved, but the absorption axis of the first polarizing layer and the slow axis of the optical compensating member must be substantially parallel to each other
Solution Approach 1:
The invention specifies precise local alignment relationships between optical components: the absorption axis of the first polarizing layer is substantially perpendicular to the optical axis of the liquid crystal layer, while the absorption axis of the first polarizing layer is substantially parallel to the slow axis of the optical compensating member. These localized alignment specifications optimize the optical compensation effect for each component's position and function within the overall display structure.
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 effectively reduces black brightness and coloring in the oblique direction, providing improved viewing-angle characteristics for black display by eliminating light leakage and compensating for wavelength dispersion effects.
Implementation Method 1
an electrical field is applied to the molecules in a lateral direction, to thereby control light transmittance and blockage
Implementation Method 2
a first polarizing layer on a light-input side; a second polarizing layer on another side, the first polarizing layer and the second polarizing layer having absorption axes substantially perpendicular to each other
Implementation Method 3
at least one optical compensating member... to reduce light leakage and coloring... compensating for wavelength dispersion effects
Data Source
AI summary
Provided is a liquid crystal display device including: a substrate (13) including a polarizing layer (11) on a light-input side; a substrate (14) including a polarizing layer (12) on another side, the polarizing layers having absorption axes substantially perpendicular; a liquid crystal layer (15) in which a liquid-crystal-molecule is aligned to be substantially horizontal to the substrates. In a case where an absorption axis of the polarizing layer (11) and an optical axis of the liquid crystal layer are substantially perpendicular, the optical compensating members (17 and 18) may be provided between the polarizing layer (11) and the liquid crystal layer; the absorption axis of the polarizing layer (11) and a slow axis of the optical compensating members are substantially perpendicular; each pixel satisfies nx≈ny≠nz; thickness-direction retardation for pixels of one color is different from other colors; and the thickness-direction retardation for red pixels is larger than 0 nm.