Liquid Crystal Display Driving Method Stabilizing Common Electrode Potential
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Solution Overview
Problem
Liquid crystal display devices in cellular telephones face challenges in maintaining high picture quality while operating in low power consumption modes, particularly during partial display operations, where flickering issues and deteriorated image quality occur due to frequent voltage variations and reduced frame frequencies.
Innovation Solution
A driving method for active matrix liquid crystal display devices that stabilizes the common electrode potential during partial display modes, varying it only during scanning periods and maintaining constant potentials in blank periods, thereby reducing flickering and power consumption without compromising picture quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the frame frequency is reduced to lower power consumption during partial display operation, then power consumption is reduced, but flickering occurs and picture quality deteriorates
Solution Approach 1:
The patent applies periodic action by implementing a dual-frame structure where odd frames scan the partial display area while even frames scan the background display area. This periodic alternation between partial and background scanning in consecutive frames maintains stable luminance and suppresses flickering even at reduced frame frequencies, thereby resolving the contradiction between low power consumption and picture quality
Solution Approach 2:
The patent segments the frame period into two distinct types: odd frames dedicated to partial display area scanning and even frames dedicated to background display area scanning. This segmentation allows independent optimization of scanning strategies for different display regions, enabling power reduction through selective scanning while maintaining overall display quality through the complementary even frames
2Productivity
If voltage is frequently varied to update display content, then display content is updated, but flickering occurs and power consumption increases
Solution Approach 1:
The patent implements periodic voltage variation patterns where the common electrode potential is varied systematically in odd frames for partial display updates and in even frames for background display updates. This periodic pattern ensures that voltage changes occur at optimal intervals, maintaining display content freshness while minimizing unnecessary voltage transitions that would increase power consumption
Solution Approach 2:
The patent applies dynamics by making the common electrode potential variable rather than fixed, allowing it to be adjusted according to the scanning requirements of different frame types. The potential is dynamically set to different values (Vcom1, Vcom2, Vcom3) based on whether the current frame is odd or even, enabling flexible control of voltage variation timing and magnitude to balance display updates with power consumption
Data Source
AI summary
An active matrix type liquid crystal display device driving method for switching a partial display mode and a normal display mode. The respective data lines of the partial display area are scanned in a certain period defined as a frame period, “k” pieces (symbol “k” is integer larger than, or equal to 1) of the partial display areas are present within 1 screen, a common electrode potential is varied 2k times within 1 frame period; a common electrode potential in a partially scanning period for scanning the partial display area is made as a constant potential against a reference of a driving circuit for driving the data lines; and within at least two continued frames, a common electrode potential of a blank period other than the partially scanning period is made as a constant potential which is different from the constant potential in the partially scanning period.