LCD Gate Pulse Overlap for Pixel Charging Speed
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Solution Overview
Problem
Existing LCD devices have a slow response time due to inadequate charging of liquid crystal cells, leading to poor picture quality, especially in dot or line inversion modes where polarity changes, causing incomplete charging and reduced modulation width.
Innovation Solution
An apparatus and method for driving LCD devices that involve overlapping gate pulses by half a horizontal period or less between adjacent gate lines, with a data driver synchronizing data voltage with gate pulses, and a timing controller to manage the overlap, allowing for a shorter pre-charging period and improved charging properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If gate pulses are overlapped by half a horizontal period to pre-charge the liquid crystal cell, then the response time is improved, but the main-charge time increases due to opposite polarity in dot or line inversion modes
Solution Approach 1:
The patent applies preliminary action by pre-charging the liquid crystal cell with the same polarity as the upcoming data voltage. Instead of using overlapping gate pulses that cause polarity reversal, the invention pre-charges the cell during the previous horizontal period so that when the new data voltage is applied, the cell is already at the correct polarity, eliminating the need for extended main-charge time to overcome opposite polarity effects.
Solution Approach 2:
The patent inverts the conventional pre-charging approach. Rather than pre-charging with opposite polarity (which requires longer main-charge time to correct), the invention pre-charges with the same polarity as the incoming data signal. This reversal of the pre-charging polarity strategy eliminates the charging delay problem in dot and line inversion modes.
2Manufacturing precision
If the modulation width of data voltage is increased to improve picture quality, then the charging completeness is improved, but the main-charge time increases further
Solution Approach 1:
By pre-charging the liquid crystal cell with the correct polarity before the data voltage is applied, the invention reduces the burden on the main-charge phase. The cell is already partially charged to the correct voltage level and polarity, so the main-charge time only needs to complete the charging process rather than overcoming opposite polarity, allowing for adequate charging completeness without excessive main-charge time.
Data Source
AI summary
An apparatus for driving a liquid crystal display device comprises a display area which includes a plurality of liquid crystal cells in portions defined by a plurality of gate and data lines; a gate driver which supplies overlapped gate pulses to the adjacent gate lines; a data driver which supplies a data voltage to the data line in synchronization with the gate pulse; and a timing controller which controls an overlapped section of the gate pulses supplied to the adjacent gate lines.