Pixel Driving Circuit Voltage Consistency LCD
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Solution Overview
Problem
Conventional pixel driving circuits in LCD devices experience voltage inconsistencies across the array substrate common voltage line, leading to abnormal image display due to voltage deviations in different areas, which affects the overall display quality.
Innovation Solution
The proposed pixel driving circuit connects the drain of the third TFT in each sub-pixel row to the first end of the second LC capacitor of the corresponding sub-pixel in the next row, ensuring that the voltage is released without affecting the array substrate common voltage line, thereby maintaining consistent voltage values across all areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the voltage at one end of the second LC capacitor is released to the array substrate common voltage line, then the color shift at large view angle is improved, but the array substrate common voltage deviates from the initially set voltage value, resulting in abnormal display
Solution Approach 1:
The pixel circuit is divided into a main area and a sub-area, with separate TFTs and LC capacitors for each area. The sub-pixel is further segmented into multiple functional blocks (main TFT T10, sub TFT T20, auxiliary TFT T30, main LC capacitor C11, sub LC capacitor C12) that can be independently controlled. This segmentation allows different voltage differences to be applied to different areas, correcting color shift while isolating the voltage release operation from the common voltage line.
Solution Approach 2:
The invention introduces an auxiliary TFT (T30) and a second LC capacitor (C12) as intermediary elements between the sub-pixel and the common voltage line. Instead of directly connecting the sub-pixel to the common voltage line Acom, the voltage is released through the auxiliary TFT and second LC capacitor, which act as buffers. This intermediary structure prevents direct voltage fluctuations from affecting the common voltage line, thus maintaining voltage stability while still achieving color shift correction.
2Ease of manufacture
If different voltage differences are applied to main area and sub-area to improve color shift, then display quality at large view angle is improved, but voltage inconsistency across the array substrate common voltage line occurs
Solution Approach 1:
The array substrate is segmented into multiple independent pixel circuits, each with its own main area and sub-area. Each pixel circuit has dedicated TFTs and LC capacitors that can be independently controlled. This segmentation allows each pixel to maintain its own voltage differences for color shift correction without affecting the voltage consistency of the common voltage line, as each pixel operates independently with isolated voltage release paths.
Solution Approach 2:
The invention maintains equipotentiality of the array substrate common voltage line by providing a dedicated common voltage line (Acom) that is kept at a stable reference potential. The auxiliary TFT and second LC capacitor in each pixel circuit serve as local voltage regulation elements that can release excess voltage locally without disrupting the global equipotential state of the common voltage line, thus maintaining voltage consistency across the entire array substrate.
Data Source
AI summary
The invention provides a pixel driving circuit and LCD device. The pixel driving circuit electrically connects the drain of the third TFT of each sub-pixel in the N-th sub-pixel row to the first end of the second LC capacitor of a corresponding sub-pixel of the (N+1)th row. When driving, when scanning the N-th sub-pixel row, the third TFT of the N-th sub-pixel row turns on to release the voltage at the first end of the second LC capacitor of the N-th sub-pixel row to the first end of the second LC capacitor of the (N+1)th sub-pixel row, and does not affect the voltage on the array substrate common voltage line, thereby effectively ensuring consistent voltage value for various areas on the array substrate common voltage line. When applied to LCD device, the invention can improve the display quality of the LCD device.