Touch Detection Method Using Split Vertical Blanking Intervals
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Solution Overview
Problem
Current touch detection methods in display devices can only perform a single touch detection procedure within one frame period, limited by the availability of vertical blanking intervals, which restricts the number and timing of touch detections.
Innovation Solution
The method involves creating two discontinuous vertical blanking intervals within each frame period, allowing multiple touch detections to be performed within these intervals, and also utilizes horizontal blanking intervals by initiating touch detections through a detection start signal to perform touch detections on different blocks of the display device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If touch detection is performed only during vertical blanking interval, then noise interference is minimal, but the number of touch detections per frame period is limited to one
Solution Approach 1:
The vertical blanking interval is divided into two separate parts: a first vertical blanking interval after the gate driver finishes scanning, and a second vertical blanking interval before the gate driver starts scanning the next frame. This segmentation allows the touch detection circuit to perform multiple touch detections during different segments of the blanking period, thereby increasing touch detection frequency while maintaining low noise conditions in each segment
Solution Approach 2:
Touch detection is performed periodically at multiple discrete time points within the frame period - specifically during the first vertical blanking interval and the second vertical blanking interval. This periodic action pattern enables multiple touch detections per frame while ensuring each detection occurs during a low-noise blanking period
2Productivity
If horizontal blanking interval is used for touch detection, then more detection opportunities are available, but the interval is too short to complete full touch detection procedure
Solution Approach 1:
The display frame is divided into multiple scanning periods with multiple horizontal blanking intervals, and the touch detection task is segmented across these intervals. Each horizontal blanking interval performs a partial touch detection on specific pixel blocks, and the results are accumulated to form complete touch detection information, thereby completing the full touch detection procedure through multiple short intervals
Solution Approach 2:
Instead of attempting to complete the entire touch detection procedure in a single long interval, the system performs partial touch detections on different pixel blocks during different horizontal blanking intervals. This partial action approach allows the system to utilize the limited time in each short blanking interval effectively while accumulating complete detection results across multiple intervals
Data Source
AI summary
A method for touch detection is provided for detecting a touch point on a display device. The method includes: providing a display signal, according to which the display device has two parts of a vertical blanking interval within each frame period, wherein the two parts of the vertical blanking interval are discontinuous; and performing a touch detection in the two parts of the vertical blanking interval, respectively. The touch detection method is capable of performing multiple touch detections within one frame period.