TFT-LCD Driver Memory Read Timing Control for Tearing Effect
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Solution Overview
Problem
The conventional TFT-LCDs experience a 'tearing effect' when using interlaced scanning video transmitting methods, where approximately 50% of the prior video frame's data is retained, leading to improper video frame display due to improper read modes in the driver's memory, and this is exacerbated by increased power consumption.
Innovation Solution
A method for reading/writing memory that introduces a delayed read timing, where data is not read from the memory until after it has been written, allowing for asynchronous operations, and includes specific steps such as writing M video input data and then starting to output odd data when the [(M/2)+1]th data is written, and switching to even data output when the Mth data is written, effectively eliminating the tearing effect without requiring additional memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If interlaced scanning video transmitting method is used, then power consumption is reduced, but tearing effect occurs due to improper read mode in memory
Solution Approach 1:
The patent applies preliminary action by pre-writing video data into the memory buffer before the display panel is ready to read it. The driver controller writes video data sequentially into the memory, and only after the writing is complete does it start reading the data for display. This timing control ensures that the display panel always reads the most recent complete frame data, preventing the tearing effect while maintaining interlaced scanning's low power consumption benefits.
2Reliability
If sequence transmitting method is used, then video data is transmitted correctly, but power consumption increases due to AC common voltage inversion on each scan line
Solution Approach 1:
The patent uses preliminary action by pre-writing the complete video frame data into the memory buffer before the display panel starts reading it. The driver controller manages the timing so that writing completes before reading begins, ensuring data integrity while enabling interlaced scanning mode that reduces power consumption by inverting AC common voltage only once per frame instead of per scan line.
3Loss of energy
If interlaced scanning mode is used, then power consumption is reduced, but 50% of prior video frame data is retained causing tearing effect
Solution Approach 1:
The patent applies preliminary action by ensuring that the complete video frame data is written into the memory buffer before the display panel begins reading it. The driver controller coordinates the writing and reading operations in such a way that the display panel always accesses the most recent complete frame data, preventing any retention of prior frame data and eliminating the tearing effect while maintaining interlaced scanning's energy efficiency.
Data Source
AI summary
A driver for driving a display panel and a method for reading/writing in a memory thereof and thin film transistor liquid crystal display (TFT-LCD) using the same are provided. The method of the present invention is a reading timing of memory which different than the prior reading timing of memory, so that, if using the method of the present invention in the driver even having only one memory, the tearing effect of the prior TFT-LCD can be solved and the whole power consumption thereof can also be reduced.