Circular Polarizer Angular Alignment for Reflective LCD Color Correction
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Solution Overview
Problem
Reflective liquid crystal displays (LCDs) suffer from color differences and reduced brightness due to path differences in reflected light, leading to a yellowish tint and lower light transmittance compared to transmissive LCDs.
Innovation Solution
A circular polarizer is designed with a polarizing film having an absorption axis at 85° to 95° and a ¼ wavelength plate with an optical axis at 130° to 140° relative to the liquid crystal alignment direction, using a poly vinyl alcohol film with specific transmittance and color coordinates, and a monoaxial oriented film for improved light conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a reflective LCD uses external light as a light source, then power consumption is reduced and the display becomes thinner and lighter, but light transmittance is reduced and brightness is lowered
Solution Approach 1:
The patent optimizes the optical parameters of the circular polarizer components, specifically setting the absorption axis of the polarizing film at 85°-95° and the optical axis of the 1/4 wavelength plate at 130°-140° relative to the liquid crystal alignment direction. These parameter adjustments improve light transmittance and brightness while maintaining the reflective LCD's low power consumption characteristics
2Use of energy by moving object
If a reflective LCD uses external light as a light source, then power consumption is reduced, but a yellowish phenomenon occurs due to path difference of reflected light, deteriorating color tone
Solution Approach 1:
The patent specifies precise angular parameters for the circular polarizer components (absorption axis at 85°-95°, optical axis at 130°-140°) to compensate for the path difference of reflected light. These parameter changes shift the white light from the yellow region to the blue region in CIE coordinates, eliminating the yellowish tint while preserving the low power consumption advantage
Solution Approach 2:
The patent directly addresses the color tone deterioration by adjusting the optical configuration to shift the perceived color from yellow to blue. The specific angular parameters of the polarizing film and wavelength plate are designed to correct the color imbalance caused by reflected light path differences
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 visibility and color tone by shifting the white light from a yellow region to a blue region, improving brightness and color balance in reflective LCDs.
Implementation Method 1
a polarizer including a polarizing film in which an absorption axis has an angle of about 85° to about 95° with respect to a liquid crystal alignment direction of a liquid crystal cell
Implementation Method 2
a 1⁄4 wavelength plate in which an optical axis has an angle of about 130° to about 140° with respect to the liquid crystal alignment direction of the light crystal cell
Data Source
AI summary
Provided are a circular polarizer and a reflective liquid crystal display including the same. The circular polarizer includes a polarizer comprising a polarizing film in which an absorption axis has an angle of about 85° to about 95° with respect to a liquid crystal alignment direction of a liquid crystal cell, where, in CIE coordinates, a color “a” is about −1 to about −0.6 and a color “b” is about 0.3 to about 2.5 and a ¼ wavelength plate in which an optical axis has an angle of about 130° to about 140° with respect to the liquid crystal alignment direction of the light crystal cell. When the circular polarizer is used, the visibility and color tone of the reflective liquid crystal display may be improved.