Pixel Circuit Segmentation for LCD Side View Color Washout
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Solution Overview
Problem
Conventional liquid crystal display (LCD) devices, particularly vertical alignment (VA) LCDs, suffer from the color washout phenomenon at side view angles, with existing solutions only managing to limit luminance to gamma 2.2 at certain grey levels, which is not satisfactory.
Innovation Solution
A pixel circuit design that includes three sub-electrode control circuits electrically coupled to successively arranged data and scan lines, allowing for the control of transparency in multiple pixel areas through data reception and charge sharing, enabling the generation of multiple electric potentials for varied luminance, thereby improving side view angle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional VA LCD device is used to achieve wider view angle than TN LCD device, then view angle range is improved, but color washout phenomenon occurs at side view angles
Solution Approach 1:
The pixel circuit is divided into three sub-pixel areas (first, second, and third sub-pixel areas) with different transparency control mechanisms. Each sub-pixel area is controlled by dedicated control circuits that can independently adjust transparency, allowing different parts of the same pixel to have different optical properties to compensate for side view angle color washout
Solution Approach 2:
Different sub-pixel areas are assigned different transparency characteristics and control strategies. The first sub-pixel area uses data from the first data line, the second sub-pixel area uses data from the second data line, and the third sub-pixel area uses modified data through charge sharing, creating local variations in transparency to correct color washout at specific viewing angles
2Object-affected harmful factors
If conventional method divides each pixel circuit into two sub-pixels with different voltages to limit luminance to gamma 2.2, then color washout is partially limited, but the improving effect is not satisfactory and luminance is limited only at certain grey levels
Solution Approach 1:
The pixel circuit is segmented into three sub-pixel areas instead of the conventional two, with each area having independent transparency control through dedicated control circuits. This segmentation provides finer granularity for luminance adjustment and enables continuous luminance control across multiple grey levels rather than being limited to specific grey levels
Solution Approach 2:
The pixel circuit employs dynamic charge sharing between capacitors (first capacitor and second capacitor) controlled by the third scan line to continuously adjust the transparency of the third sub-pixel area. This dynamic adjustment mechanism enables precise luminance control across a wider range of grey levels, improving luminance control accuracy beyond static voltage assignment methods
Data Source
AI summary
An exemplary pixel circuit and a flat display panel using the same are provided. The pixel circuit includes three sub-electrode control circuits. The sub-electrode control circuits are controlled by two scan lines to receive data transmitted from two data lines. One of the three sub-electrode control circuits adjusts stored data by charge sharing. Accordingly, a display control of the pixel circuit is achieved by the three sub-electrode control circuits.