Color Filter Substrate Alignment in COA Display Devices
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Solution Overview
Problem
In liquid crystal display devices, misalignment of pixel electrodes and color filters due to substrate misalignment during the layering process leads to color mixture and decreased aperture ratio, especially in high-definition displays where narrower pixels exacerbate this issue, affecting image quality.
Innovation Solution
A color filter substrate design where pixel electrodes and color filters are formed on the same substrate, with a specific arrangement of signal lines, switching elements, and apertures to ensure precise alignment and reduce positional shifts, implemented in a COA (Color-Filter-On-Array) scheme, which enhances the aperture ratio and minimizes color mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel width is reduced to achieve higher definition, then image resolution is improved, but misalignment between pixel electrodes and color filters occurs more frequently and severely
Solution Approach 1:
The invention introduces a light-shielding layer with light-shielding portions positioned between adjacent color filters. This segmentation approach creates physical barriers that prevent light from adjacent pixels from reaching the wrong color filter, thereby preventing color mixture even when misalignment occurs. The light-shielding portions are strategically placed to bridge the gap between color filters, effectively dividing the optical path and ensuring that each color filter receives light only from its corresponding pixel electrode.
2Ease of manufacture
If substrates are misaligned during layering process, then positional relationship between pixel electrodes and color filters shifts, but this causes color mixture and decreased aperture ratio
Solution Approach 1:
The light-shielding layer is formed in advance during the substrate manufacturing process, before the final assembly and layering. This preliminary action ensures that the light-shielding portions are already in place to compensate for any potential misalignment that may occur during the layering process. The light-shielding layer acts as a pre-configured correction mechanism that automatically addresses alignment issues without requiring post-assembly adjustments.
3Illumination intensity
If aperture ratio is increased to improve luminosity, then brightness is improved, but color mixture between adjacent pixels may occur
Solution Approach 1:
The invention converts the potential harmful effect of light spreading (which causes color mixture) into a beneficial effect by using the light-shielding layer to guide and confine light paths. The light-shielding portions strategically block light that would otherwise spread to adjacent pixels, while allowing sufficient light to pass through the aperture to maintain high luminosity. This approach effectively manages light distribution to prevent color mixture while preserving brightness.
Data Source
AI summary
In an embodiment, a color filter substrate includes an substrate, first to fifth lines, first to third switching elements, first to third electrodes, color filter layer between electrodes and the substrate, and insulating layer with first to third apertures. The first electrode is formed in a first area defined by lines at the first line side, and the second electrode is formed in the first area at the second line side. The third electrode is formed in a second area defined by lines. Electrodes are connected to switching elements through apertures respectively. The first aperture is formed at the first line side, and the second aperture is formed at the second line side.