Reflective LCD Blue Filter Light Blocking for Yellowish White Coordinates
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Solution Overview
Problem
In liquid crystal display (LCD) devices with a four-color pixel structure, the smaller blue pixel area leads to yellowish white coordinates due to insufficient blocking of red and green light by the blue color filter, and red and blue light by the green color filter, resulting in deteriorated color saturation and reproducibility, especially in reflective and transflective LCDs that lack a separate backlight.
Innovation Solution
The LCD is designed with red, green, and blue color filters having an overall area smaller than the red and green filters, with the blue filter blocking green light better than the red filter and blocking red light better than the green filter, and the pixel arrangement is optimized to position blue and white pixels diagonally opposite to red and green pixels, ensuring effective light blocking and preventing yellowish white coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the area of blue pixels is reduced in a four-color LCD to improve resolution and luminance, then the overall pixel density increases, but the blue pixel area becomes relatively smaller causing white coordinates to shift toward red and green areas resulting in yellowish white coordinates
Solution Approach 1:
The patent applies local quality by making the blue color filter's light blocking capability locally stronger than that of red and green filters. Specifically, the blue color filter is designed to block green light better than the red filter blocks green light, and to block red light better than the green filter blocks red light. This localized enhancement in the blue filter's performance compensates for the reduced blue pixel area, preventing white coordinate shift and yellowish appearance while maintaining high resolution and luminance.
2Illumination intensity
If conventional color filters with high transmittance are used to maximize luminance, then light loss is minimized, but the color filters cannot sufficiently block other colors leading to deteriorated color saturation and reproducibility
Solution Approach 1:
The patent applies parameter changes by modifying the light blocking characteristics of the blue color filter specifically. Instead of uniformly increasing the blocking capability of all color filters (which would reduce luminance), the invention selectively enhances the blue filter's ability to block red and green light. This parameter change in the blue filter's spectral properties allows it to maintain high transmittance for blue light (preserving luminance) while simultaneously improving its blocking performance for other colors (enhancing color saturation and reproducibility).
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 color reproducibility by reducing red and green elements in the blue pixel area, preventing white coordinates from appearing yellowish and improving the overall color accuracy and luminance of the LCD.
Implementation Method 1
the blue filter blocking green light better than the red filter and blocking red light better than the green filter
Data Source
AI summary
A reflective liquid crystal display (LCD) is provided for efficiently preventing white coordinates from being yellowish. The LCD includes a substrate having red color filters, green color filters, and blue color filters. The blue color filters have an overall area smaller than that of the red color filters and the green color filters while blocking green light better than the red color filters and blocking red light better than the green color filters.