Liquid Crystal Display Color Filters for Uneven Backlight Compensation
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Solution Overview
Problem
Liquid crystal display devices suffer from luminance inconsistencies due to uneven illumination, particularly at the outer periphery, leading to decreased in-plane luminance uniformity and visibility issues when used in tiled displays.
Innovation Solution
A liquid crystal display device with a dual illumination system featuring regions of varying luminance, combined with color filters in pixels that have different transmittance ratios to compensate for luminance differences, ensuring uniformity by adjusting the transmittance of light across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local dimming is implemented to control backlight brightness by area units, then high contrast is achieved, but luminance uniformity in the display region decreases
Solution Approach 1:
The invention applies local quality by differentiating pixel structures between first and second regions. Pixels in the first region (higher luminance area) have color filters with only a first transmittance, while pixels in the second region (lower luminance area) have color filters with both first and second portions where the second portion has higher transmittance. This local differentiation compensates for the luminance decrease in the outer periphery while maintaining the local dimming contrast effect.
Solution Approach 2:
The invention changes the transmittance parameter of the color filter to compensate for luminance differences. By adjusting the ratio of the second portion (higher transmittance) relative to the first portion in pixels of the second region, the invention compensates for the reduced light supply from the backlight, thereby improving in-plane luminance uniformity without sacrificing the contrast benefit of local dimming.
2Device complexity
If light emitting elements are not disposed in the outermost periphery area, then device complexity is reduced, but luminance uniformity decreases
Solution Approach 1:
Instead of adding complex structures to the backlight, the invention changes the transmittance parameter of the color filter in pixels located in the second region. By increasing the transmittance of the second portion in these pixels, the invention compensates for the reduced light supply from the backlight's uneven illumination, thereby improving luminance uniformity without increasing backlight structure 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
Enhances in-plane luminance uniformity and reduces power consumption by compensating for luminance decreases, minimizing visible seams between displays and maintaining consistent brightness across the screen.
Implementation Method 1
a pixel provided in the second region of the liquid crystal display includes a color filter including a first portion having a first transmittance, and a second portion having a second transmittance higher than the first transmittance
Data Source
AI summary
An illuminator includes a first illumination region having a first luminance and a second illumination region having a second luminance that is lower. A liquid crystal display includes a first region illuminated by the first illumination region and a second region illuminated by the second illumination region. A pixel in the second region includes a color filter including a first portion having a first transmittance and a second portion having a second transmittance that is higher. A pixel in the first region includes a color filter including only the first portion, or includes a color filter including the first portion and the second portion and a ratio of the second portion to the first portion and the second portion in the pixel in the second region is greater than a ratio of the second portion to the first portion and the second portion in the pixel in the first region.