LCD Polarity Inversion for DC Image Sticking
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Solution Overview
Problem
Liquid crystal display (LCD) devices suffer from DC image sticking and flicker, which degrade display quality due to prolonged dominance of data voltages with opposite polarities and periodic brightness differences.
Innovation Solution
A liquid crystal display device and driving method that alternately arrange liquid crystal cell groups with inverted and non-inverted polarity patterns, coupled with a timing controller generating polarity control signals to vary polarity levels at frame intervals, ensuring data voltages are supplied with inverted polarities in one group and identical polarities in another, alternating their positions vertically every two horizontal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data voltages are supplied in accordance with an interlace scheme with polarity inversion at frame intervals, then DC offset components are reduced and liquid crystal degradation is minimized, but DC image sticking occurs due to prolonged dominance of data voltages with the same polarity
Solution Approach 1:
The display panel is divided into multiple scan line groups (odd and even groups), and data voltages are supplied to different groups with different polarity patterns. This segmentation allows each group to experience balanced polarity alternation, preventing the cumulative polarity dominance that causes DC image sticking while maintaining the benefits of frame-by-frame polarity inversion for liquid crystal protection.
2Reliability
If polarity inversion occurs between neighboring liquid crystal cells and at frame intervals, then DC offset components are reduced, but image sticking occurs when data voltages with opposite polarities are dominantly supplied for prolonged periods
Solution Approach 1:
Different polarity control patterns are applied to different spatial regions (scan line groups) of the display panel. Odd scan line groups receive one polarity pattern while even scan line groups receive an inverted polarity pattern, creating local quality variations that prevent uniform polarity dominance across the entire panel, thereby eliminating image sticking while maintaining overall display stability.
3Object-affected harmful factors
If data voltages are supplied with frequent polarity changes to prevent DC image sticking, then image distortion is reduced, but flicker occurs due to periodic brightness differences
Solution Approach 1:
The patent implements periodic polarity inversion at frame intervals for each scan line group, creating a regular alternating pattern that prevents DC image sticking. By synchronizing this periodic action with the display refresh rate and using complementary patterns across different scan line groups, the system maintains stable average brightness while preventing image distortion, effectively eliminating flicker.
Data Source
AI summary
A liquid crystal display (LCD) device and a driving method can produce reduced direct current image sticking and flicker. An LCD panel for the LCD device has liquid crystal cells having a common same color in each horizontal line and has columns of liquid crystal cells having a repeating sequence of color, a timing controller for generating a polarity control signal such that the polarity control signal is varied at intervals of one frame period, a data driving circuit supplying data voltages to the data lines in response to the polarity control signal, and a gate driving circuit supplying scan pulses to the gate lines. The liquid crystal cells include first liquid crystal cell groups supplied with data voltages having polarities inverted from polarities the previous frame period, and second liquid crystal cell groups supplied with data voltages having polarities identical to the polarities supplied in the previous frame period.