Display Drive Device Field Through Voltage Control
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Solution Overview
Problem
In active-matrix liquid crystal display panels, the 'field through phenomenon' causes pixel electrode voltage asymmetry, leading to flicker and liquid crystal molecule sticking, which existing methods fail to adequately control due to insufficient cancellation of the field through voltage's direct current component.
Innovation Solution
The display drive device incorporates a gradation voltage setting circuit that reverses and adjusts gradation voltages, using a voltage divider circuit and correction voltages to maintain a constant change characteristic, thereby controlling the field through voltage's effect on the display signal voltage, ensuring linear or nonlinear change inclination to stabilize the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional data driver configuration with changeover switches and division resistance is used, then polarity changeover control is achieved, but field through voltage fluctuation cannot be adequately controlled
Solution Approach 1:
The invention changes the voltage range parameters by switching between first and second gradation voltage groups with different voltage ranges. The first group has a smaller voltage range while the second group has a larger voltage range, allowing dynamic adjustment to control field through voltage fluctuations and improve display quality stability.
Solution Approach 2:
The invention dynamically switches between different gradation voltage groups based on the polarity changeover signal. The data driver can select from multiple stored gradation voltage groups, making the system adaptive and dynamic rather than static, thereby controlling harmful voltage fluctuations.
2Reliability
If fixed gradation voltage range is used, then circuit simplicity is maintained, but display quality deteriorates due to field through phenomenon
Solution Approach 1:
The invention performs preliminary action by pre-storing multiple gradation voltage groups in the data driver before operation. These groups are prepared in advance with different voltage ranges, allowing the system to quickly switch to appropriate groups without complex real-time calculations, thus improving display quality without excessive circuit complexity.
Solution Approach 2:
The invention creates copies of gradation voltage tables in different polarity states. By storing multiple gradation voltage groups that correspond to different polarity conditions, the system can select the appropriate copy based on the current state, simplifying the control logic while improving display quality.
3Reliability
If center voltage is not adjusted in polarity changeover, then circuit operation is simple, but pixel electrode voltage asymmetry occurs causing flicker
Solution Approach 1:
The invention intentionally introduces asymmetry by adjusting the center voltage differently for different polarity states. The gradation voltage groups are designed with different voltage ranges and center points corresponding to positive and negative polarity states, creating an asymmetric control scheme that compensates for the inherent asymmetry in pixel electrode voltage caused by field through phenomenon.
Data Source
AI summary
A display drive device applied to a display device which drives a display panel (110) comprising a plurality of display pixels (Px) which comprises a gradation voltage setting circuit (40a, 40c) which sets a plurality of gradation voltages and voltage ranges according to each luminosity gradation of the display data, which reverses the gradation voltages for each luminosity gradation of the display data in a predetermined period while providing a change characteristic of the center voltage in reversal of the gradation voltages for each luminosity gradation corresponding to the change inclination of the field through voltage produced when the display signal voltage of each luminosity gradation is applied, and which maintains this change characteristic constant for changing the voltage range value; and a gradation conversion circuit (30a, 30d) which produces display signal voltages based on gradation voltages corresponding to the luminosity gradations of the display data.