VA Type TFT Array Substrate with Three Pixel Electrodes
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Solution Overview
Problem
Vertical alignment (VA) type LCDs suffer from a smaller viewing angle compared to other types, leading to image distortion when viewed from different directions due to uneven brightness across the display.
Innovation Solution
A manufacturing method for a VA type TFT array substrate that includes forming three pixel electrodes connected to the same TFT but located on different structure layers, allowing for differential liquid crystal transmittance adjustments across regions of a pixel to maintain brightness uniformity when viewed from various angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional single pixel electrode structure is used in VA type LCD, then the manufacturing process is simple, but the viewing angle is small and image distortion occurs when viewed from different directions
Solution Approach 1:
The pixel electrode is divided into three separate pixel electrodes (first, second, and third pixel electrodes) located at different positions within the same pixel region. Each pixel electrode is connected to the same TFT but positioned to control liquid crystal transmittance in different areas, thereby improving viewing angle characteristics by enabling differential transmittance adjustment across the pixel.
Solution Approach 2:
The invention introduces a vertical layering dimension by positioning the three pixel electrodes at different heights within the pixel structure. The first pixel electrode is at a lower layer, the second pixel electrode is at an intermediate layer, and the third pixel electrode is at an upper layer, allowing for three-dimensional control of liquid crystal alignment and light transmittance from different angular perspectives.
2Illumination intensity
If three pixel electrodes are formed in one pixel to improve viewing angle, then the brightness uniformity from different angles is enhanced, but the manufacturing process complexity increases with multiple photomask processes
Solution Approach 1:
The formation of three pixel electrodes is merged into a single photomask process step. The photomask pattern is designed to simultaneously define all three pixel electrodes in their respective positions, allowing them to be formed in one deposition and patterning cycle rather than requiring separate processes for each electrode.
Solution Approach 2:
A single TFT structure serves multiple functions by controlling all three pixel electrodes simultaneously. The TFT acts as a common switch that can modulate the voltage applied to each of the three pixel electrodes, enabling the device to achieve improved viewing angle characteristics while maintaining a relatively simple transistor control architecture.
Data Source
AI summary
The present invention provides a VA type TFT array substrate and a manufacturing thereof. The manufacturing method for a VA type TFT array substrate of the present invention comprises that three pixel electrodes are formed in one pixel. The three pixel electrodes are connected to the same TFT but located on different structure layers. Therefore, the driving capabilities to liquid crystals are different. In the present invention, the three pixel electrodes are used to adjust the liquid crystal transmittances of three regions in one pixel, which is beneficial of keeping the brightness uniformity of the pixel when seeing from different angels, thereby enhancing the viewing angle of the VA type LCDs. The VA type TFT array substrate of the present invention disposes three pixel electrodes are formed in one pixel, which is beneficial of enhancing the viewing angle of the VA type LCDs.