In-Cell Touch Screen Driving via Horizontal Sync Signals
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Solution Overview
Problem
In-cell type touch screen displays face limitations in driving modes, where touch data is transmitted infrequently relative to display frame rates, leading to reduced touch sensitivity and accuracy due to time-divisional driving based on vertical sync signals.
Innovation Solution
A display device with integrated touch screen that drives display and touch modes using horizontal sync signals, employing a touch IC to apply touch scan signals to electrodes during low logic periods of the horizontal sync signal, ensuring at least one application per frame, thereby increasing touch report rates and improving sensing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If touch data is transmitted once every vertical sync signal to define one frame period, then the display device can maintain simple time-divisional driving, but the touch report rate is low and touch sensitivity is reduced
Solution Approach 1:
The patent segments the frame period into multiple touch scanning cycles by utilizing horizontal sync signals. Instead of a single touch scan per vertical sync, the system performs multiple touch scans within one frame period, effectively segmenting the time resource to increase touch report rate without requiring separate driving circuits.
Solution Approach 2:
The patent dynamically adjusts the touch scanning frequency by leveraging the horizontal sync signal rhythm. The touch IC applies touch scan signals to electrodes multiple times during one frame, creating a dynamic scanning pattern that increases touch responsiveness while maintaining integration with the display timing structure.
2Measurement precision
If touch data is transmitted only once per frame period, then memory requirements remain low, but touch accuracy and responsiveness are reduced
Solution Approach 1:
The patent implements periodic touch scanning by applying touch scan signals multiple times during each frame period. This periodic action allows the system to accumulate more touch data points without requiring proportionally more memory, as the additional scans occur within the same temporal window and can be processed efficiently.
3Ease of operation
If display and touch driving are time-divisional based on vertical sync signals, then the driving structure is simple, but touch sensitivity is reduced
Solution Approach 1:
The patent makes the horizontal sync signal serve multiple functions: it continues to synchronize display timing while simultaneously serving as the trigger for multiple touch scanning cycles. This multi-functionality allows the system to maintain simple integrated driving architecture while significantly improving touch sensitivity through increased scanning frequency.
Data Source
AI summary
Discussed is a display device with integrated touch screen including a panel including a plurality of electrodes; a data driver for converting RGB data inputted from a timing controller into a data voltage, and supplying the data voltage to data lines; a gate driver for sequentially supplying a gate signal to gate lines so as to apply the data voltage to pixels of the panel during a high logic period of a horizontal sync signal; and a touch IC for supplying the touch scan signal to the plurality of electrodes every low logic period of the horizontal sync signal, wherein the touch IC applies the touch scan signal, at least once, to each of the electrodes during one frame.