Touch Sensor Driver Circuit Vertical Blanking Period Segmentation
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Solution Overview
Problem
Existing touch sensors in display devices face challenges in achieving high touch recognition rates due to limited operating time, which degrades touch sensitivity and video display quality, as they often require time division between display and touch sensing, leading to inadequate touch sensitivity and operational inefficiency.
Innovation Solution
A driver circuit for touch sensitive display devices that divides the vertical frame period into display and touch periods, allowing touch sensing during the vertical blanking period, thereby increasing touch report rate without reducing display time or memory clock frequency, and enhancing touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If touch sensing is performed during the vertical blanking period only, then touch sensitivity is improved, but touch report rate is limited
Solution Approach 1:
The patent divides the touch sensing operation into two segments: first touch sensing during the vertical blanking period and second touch sensing during the vertical active period. This segmentation allows the system to accumulate touch sensing opportunities throughout the frame period, thereby increasing the touch report rate while maintaining adequate touch sensitivity through the combined sensing time from both segments.
2Measurement precision
If display time is reduced to increase touch sensing time, then touch sensitivity is improved, but video display quality is degraded
Solution Approach 1:
The patent implements dynamic time allocation by performing touch sensing at two different time points within the frame period (vertical blanking period and vertical active period) rather than allocating a fixed continuous time segment. This dynamic approach allows the display time to remain unchanged while touch sensing utilizes otherwise underutilized time periods, thereby improving touch sensitivity without compromising video display quality.
3Adaptability or versatility
If time division scheme is used between display and touch sensing, then both functions can be implemented, but operating time for touch sensor is insufficient
Solution Approach 1:
The patent performs preliminary touch sensing during the vertical blanking period before the display active period begins, and then performs additional touch sensing during the vertical active period. This preliminary and supplemental sensing approach ensures that the touch sensor has adequate operating time accumulated throughout the frame period, resolving the insufficiency of touch sensor operating time while maintaining the time division scheme for dual function implementation.
Data Source
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AI summary
A method for driving a display device including a display panel (100) including a first and a second display area each of which is divided into a plurality of display blocks (D_Block1, ..., D_Blockn) and n touch blocks comprises a first and a second step. The first step drives the respective display blocks of the first display area sequentially, drives at least one touch block after driving the display blocks, and generates a first touch report after driving all of the n touch blocks. The second step drives the respective display blocks of the second display area sequentially, drives at least one touch block after driving the display blocks, and generates a second touch report after driving the n touch blocks again. The first and the second step are processed within one frame period (F1), and the one frame period (F1) includes a vertical blanking interval (VB) void of input image data.