Display Circuit Switching During Vertical Blanking for Sync Stability
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Solution Overview
Problem
Existing display systems face synchronization continuity issues during video signal switching, leading to unstable synchronization and image distortion due to asynchronous vertical synchronization signals, resulting in low display visual quality.
Innovation Solution
A circuit apparatus with a first and second input circuit, a frame memory, a selection circuit, and a control circuit that controls image data switching and frame rate adjustment in vertical blanking periods to synchronize asynchronous image data, ensuring high visual quality during transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If asynchronous video signal switching is performed without synchronization continuity measures, then switching between different video sources is achieved, but synchronization stability deteriorates causing image distortion or black display periods
Solution Approach 1:
The patent applies preliminary action by preparing synchronization continuity information in advance and using it during the switching process. The system predicts the synchronization timing of the second video signal based on pre-acquired synchronization continuity information, and performs the switch during the vertical blanking period when the image is not being displayed, thereby maintaining synchronization stability without causing image distortion or black periods.
Solution Approach 2:
The patent applies preliminary action by predicting the synchronization timing of the second video signal before the actual switching occurs. The control circuit uses pre-acquired synchronization continuity information to calculate and determine the optimal switching timing, ensuring that the transition happens during the vertical blanking period and maintains synchronization continuity throughout the switching process.
2Speed
If video signal switching occurs during active display period, then real-time switching is achieved, but image quality deteriorates due to synchronization instability and distortion
Solution Approach 1:
The patent applies periodic action by utilizing the vertical blanking period - a regular, periodic interval in the video signal cycle when no image is being displayed - to perform the switching operation. This timing strategy allows the system to switch video signals without affecting the displayed image quality, as the switching occurs during the natural refresh cycle gap of the display system.
3Device complexity
If synchronization timing is not predicted and adjusted during switching, then switching simplicity is maintained, but display visual quality deteriorates due to instability and distortion
Solution Approach 1:
The patent applies feedback by using the acquired synchronization continuity information to adjust and determine the switching timing. The control circuit receives feedback about the synchronization characteristics of the video signals and uses this information to calculate the optimal switching moment, ensuring that the transition maintains synchronization continuity and prevents image distortion while improving display visual quality.
Data Source
AI summary
A first selection circuit switches from first image data to switching image data in a vertical blanking period of the first image data. An output circuit outputs output image data at a frame rate different from that of second image data in a switching period in which the switching image data is selected by the first selection circuit. The first selection circuit switches from the switching image data to the second image data in an overlap period between a vertical blanking period of the switching image data and a vertical blanking period of the second image data.