Display Panel Scan Completion Signaling to Prevent Frame Tearing
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Solution Overview
Problem
Screen tearing occurs when a display panel takes a long time to complete data writing, causing the display driver chip to prematurely activate a tear effect signal, resulting in incomplete display data for the current frame and overlapping with the next frame.
Innovation Solution
The display panel outputs a scanning-done signal after completing the data writing of a frame, allowing the display driver chip to write and output data for the next frame only after the current frame is finished, ensuring the integrity of the display by separating the time periods for writing and outputting frame data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the display driver chip activates the tear effect signal prematurely, then the display can start processing the next frame, but the current frame data writing is incomplete causing screen tearing
Solution Approach 1:
The display panel outputs a scanning-done signal after completing data writing for a frame, providing feedback to the display driver chip. This feedback mechanism ensures the driver chip knows when data writing is complete before activating the tear effect signal, preventing screen tearing while maintaining efficient frame processing.
Solution Approach 2:
The display panel performs data writing completion signaling in advance before the display driver chip activates the tear effect signal. By outputting the scanning-done signal beforehand, the system ensures that current frame data is fully written before transitioning to the next frame, preventing display tearing.
2Reliability
If the display panel takes a long time to complete data writing, then the data integrity is maintained, but the display driver chip cannot keep up with frame timing
Solution Approach 1:
The system dynamically adjusts the timing of the tear effect signal activation based on the actual data writing completion status. Instead of using fixed timing, the display driver chip waits for the scanning-done signal from the display panel, allowing flexible adaptation to varying data writing speeds while maintaining frame synchronization.
3Productivity
If the tear effect signal is activated early, then frame continuity is improved, but incomplete data writing causes screen tearing
Solution Approach 1:
The scanning-done signal provides critical feedback that confirms data writing completion. The display driver chip uses this feedback to determine the appropriate moment to activate the tear effect signal, ensuring frame continuity is maintained without causing screen tearing from premature activation.
Data Source
AI summary
A display method is applied to a display apparatus including a display panel, a display driver chip, and a microprocessor. The display method includes outputting, by the display panel, a scanning-done signal of a first frame image generated after scanning rows of pixel circuits of the display panel; after the microprocessor or the display driver chip receives the scanning-done signal, writing, by the display driver chip, initial data of a second frame image provided by the microprocessor and outputting, by the display driver chip, display data of the second frame image to the display panel based on the initial data; or outputting, by the display driver chip, the display data of the second frame image to the display panel in response to the scanning-done signal, the display data being generated based on the initial data provided by the microprocessor. The second frame image follows the first frame image.