Liquid Crystal Display Common Voltage Compensation Circuit
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Solution Overview
Problem
In liquid crystal display devices, the common voltage compensation circuit fails to uniformly compensate voltage drops across different lengths and arrangements of common lines, leading to incomplete voltage application and display quality deterioration, such as a greenish phenomenon, due to uneven current distribution.
Innovation Solution
The liquid crystal display device incorporates a common voltage compensation circuit that generates a compensated voltage by equally distributing current through first and second common lines with similar resistance and capacitance, ensuring uniform voltage application across the entire common electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common voltage compensation circuit is used to supply common voltage through common lines of different lengths and arrangements, then the common voltage can be supplied to the liquid crystal panel, but the voltage drops are not uniformly compensated across different portions of the panel, leading to display quality deterioration
Solution Approach 1:
The patent divides the common electrode into multiple regions (first common electrode region and second common electrode region) corresponding to different common lines. Each region is independently controlled by its own common voltage signal, allowing separate compensation for voltage drops in different areas. This segmentation enables uniform voltage distribution across the entire liquid crystal panel despite variations in common line lengths and arrangements.
2Area of stationary object
If common lines of different lengths are used to supply common voltage to different portions of the liquid crystal panel, then the liquid crystal panel can be fully covered, but the different resistance and capacitance of the common lines cause uneven voltage distribution and display quality issues
Solution Approach 1:
The patent applies different common voltage signals to different regions of the common electrode based on the specific characteristics of each region's common lines. By tailoring the voltage signal to each local region's needs (compensating for different line lengths, resistances, and capacitances), the system achieves uniform voltage distribution across the entire panel while maintaining full coverage area.
Data Source
AI summary
A liquid crystal display device includes: a first substrate having a display area and a non-display area surrounding the display area, the first substrate including first, second, third and fourth sides; a first common line formed in the non-display area corresponding to the second, third and fourth sides of the first substrate; a second substrate facing and spaced apart from the first substrate; a common electrode formed on an entire surface of the second substrate; and a liquid crystal layer between the first and second substrates.