LCD VCOM Polarity Hold During Display Data Rewriting
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Solution Overview
Problem
Display quality deterioration in liquid crystal display devices due to unsatisfactory display data rewriting operations, which fail to meet the specifications of the display device, leading to potential screen burn-in and image sticking issues.
Innovation Solution
A semiconductor device with a display control unit that outputs an AC signal with inverted polarity on a constant cycle, stops the polarity reversal of the AC signal during display data rewriting, and maintains the polarity until the rewriting is complete, ensuring that the display data is rewritten without interfering with the polarity inversion timing of the VCOM signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If display data rewriting operation is performed without coordinating with VCOM signal polarity inversion timing, then display data can be rewritten freely, but display quality deteriorates due to screen burn-in and image sticking
Solution Approach 1:
The control unit determines in advance whether VCOM signal polarity inversion is performed during the display data rewriting period. Based on this determination, it either prohibits rewriting during inversion periods or adjusts the rewriting timing to avoid inversion, thereby preventing display quality deterioration before it occurs
Solution Approach 2:
The system dynamically adjusts the display data rewriting operation based on the VCOM signal polarity inversion timing. The rewriting enable signal is controlled to be active only during periods when polarity inversion is not performed, making the rewriting capability adaptive to the VCOM signal state
2Reliability
If VCOM signal polarity inversion is continuously performed to prevent screen burn-in, then display quality is maintained, but display data rewriting operation is restricted
Solution Approach 1:
The system utilizes the periodic nature of VCOM signal polarity inversion to schedule display data rewriting operations. By identifying periods when polarity inversion is not performed, the system can periodically execute rewriting operations without compromising display quality protection
Solution Approach 2:
The system temporarily suspends display data rewriting during VCOM polarity inversion periods (discarding rewriting opportunity) and resumes it during safe periods (recovering rewriting capability), thereby balancing display quality maintenance with rewriting functionality
Data Source
AI summary
A display control device comprises an output unit that outputs an inverted polarity of an AC signal in a constant cycle, based on a signal of the constant cycle; a stop control unit that stops the reversal of the polarity of the AC signal in the output unit, based on a stop signal; a rewrite control unit for outputting a display data rewrite signal; and a transmission control unit for controlling the rewrite control unit. The stop signal stops the reversal of the polarity of the AC signal during a period in which the display data rewrite signal is output. The AC signal stopped by the stop signal maintains a polarity before the stop of polarity reversal. The output unit inverts and outputs the polarity of the AC signal, based on the signal of the constant cycle, after a period in which the display data rewrite signal is output.