Transflective LCD Color Filters with Light Holes for Reflectivity
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Solution Overview
Problem
Transflective liquid crystal displays face challenges in achieving high reflectivity while maintaining color accuracy, as the difference in light passage through color filters in transmissive and reflective areas affects color tone, leading to potential yellowish hues.
Innovation Solution
The design incorporates color filters with light holes in the reflective area, where the area of the light holes is between 20% to 80% of the color filter area, ensuring consistent light passage and high reflectivity, with equal-sized light holes for red, green, and blue filters, and includes a structure with a thin film transistor, common electrode, and passivation layers to enhance reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light holes are formed in color filters for reflective area, then reflectivity is improved, but color tone consistency deteriorates due to different light passage through color filters in transmissive and reflective areas
Solution Approach 1:
The patent applies local quality by forming light holes only in the color filters corresponding to the reflective area, while leaving color filters in the transmissive area intact. This localized modification allows external light to pass through the light holes and be reflected by the reflective electrode, thereby improving reflectivity in the reflective area without affecting the transmissive area's color tone. The selective placement of light holes ensures that each area maintains its optimal optical characteristics.
2Illumination intensity
If light hole size is increased to improve reflectivity, then yellowish color tone increases, but color reproducibility deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the size of light holes in color filters to achieve the desired balance between reflectivity and color reproducibility. The light hole diameter is controlled within a specific range (0.5 μm to 2.0 μm) and the light hole area ratio is maintained between 10% to 50% of the color filter area. By precisely controlling these parameters, the patent achieves high reflectivity while minimizing yellowish color tone and maintaining excellent color 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 approach increases reflectivity while minimizing yellowish color tones, achieving a white Y value greater than 45 and maintaining high color reproducibility, thereby improving the display's performance in both transmittance and reflection modes.
Implementation Method 1
The light can be provided to the liquid crystal externally, or a light emitting device can be installed in the LCD device to provide internal light to the liquid crystal. The reflective LCD device displays an image by using the external light that enters the LCD panel through the front side of the LCD panel.
Implementation Method 2
The color filters have light holes in the reflective area, where the area of the light holes is between 20% to 80% of the color filter area, ensuring consistent light passage and high reflectivity
Implementation Method 3
In response to changes in the electric filed that are applied to the liquid crystal layer, an arrangement of liquid crystal molecules of the liquid crystal layer is changed to control the transmittance of light.
Data Source
AI summary
A display device having a transmissive area and a reflective area includes a first substrate, a reflective electrode formed on the first substrate, wherein the reflective electrode is disposed in the reflective area, a second substrate facing the first substrate, a plurality of color filters formed on the second substrate, wherein the plurality of color filters have light holes in the reflective area, and a common electrode formed on the second substrate, wherein an area of the tight holes is more than about 20% of an area of the color filter in the reflective area.