Flat Display Device Voltage Polarity Control Circuit
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Solution Overview
Problem
Conventional liquid crystal display devices experience display failures and prominent brightness differences between lines when switching voltage polarity at the beginning of a frame, leading to unevenness and poor display quality, especially when displaying half tones.
Innovation Solution
A flat display device with a control circuit that provides a periodicity of every M scanning lines to the voltage polarity of signal lines and preliminarily drives the signal line corresponding to the first scanning line at the beginning of a frame, ensuring the voltage polarity of the final line in the M-line cycle is applied before driving the first scanning line, maintaining periodicity and distributing drive conditions evenly across the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage polarity of signal lines is switched at the beginning of a frame to provide periodicity, then the display can maintain chromogenic characteristics and reduce afterimages, but the periodicity may be disrupted causing display failures and brightness differences
Solution Approach 1:
The control circuit performs a preliminary action by applying the voltage polarity of the final line in the M-line cycle to the signal line before driving the first scanning line. This preliminary polarity application ensures that when the frame starts, the signal line already has the correct polarity state, preventing disruption of the periodicity and avoiding display failures or brightness differences in the first scanning line.
2Device complexity
If multi-selection drive is used to reduce driver IC complexity, then the number of connection parts is reduced, but the selection order of signal lines becomes more complex and may cause unevenness in display
Solution Approach 1:
Instead of following the conventional selection order of signal lines in the multi-selection drive, the control circuit inverts the approach by applying the polarity of the final line in the cycle to the signal line before driving the first scanning line. This inversion compensates for the complexity introduced by multi-selection drive and ensures uniform display across all scanning lines.
Data Source
AI summary
An object of the present invention is to provide a flat display device which achieves an excellent and stable display even when the periodicity of voltage polarity is switched at the beginning of a frame at the time of driving a signal line while providing a periodicity of every M scanning lines to the voltage polarity of signal lines in each frame. A control circuit 22 controls so as to provide a voltage polarity of the final line in the periodicity of every four scanning lines to a signal line prior to driving a signal line corresponding to the first scanning line Y(1) at the beginning of a frame.