Touch Sensor Scan Timing for Faster, Low-Noise Display Input
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Solution Overview
Problem
Existing display devices face challenges in achieving high operability in touch input while reducing power consumption and maintaining display quality, particularly in bright environments, due to increased touch sensing frequency causing noise and reduced accuracy, and prolonged display refreshing leading to power leakage and flickers.
Innovation Solution
A display device with integrated gate drivers and touch sensors that allow simultaneous touch sensing and display refreshing by using a novel structure with transmissive and reflective elements, and polysilicon or metal oxide transistors, enabling separate timing control for display and touch operations to minimize noise and power leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the touch sensing frequency is increased to improve operability, then touch input responsiveness is improved, but display driving signals cause noise and touch sensing accuracy is reduced
Solution Approach 1:
The patent segments the sensing period into multiple sub-periods (first sub-period and second sub-period) with different scanning methods. During the first sub-period, row-by-row scanning is performed with display driving signals active. During the second sub-period, column-by-column scanning is performed with display driving signals stopped, providing a low-noise measurement window that improves touch sensing accuracy while maintaining responsive touch input capability.
2Use of energy by moving object
If the display refreshing interval is prolonged to reduce power consumption, then power usage is reduced, but leakage of electric charges occurs and display quality deteriorates with flickers
Solution Approach 1:
The patent implements periodic touch sensing operations between display refresh cycles. Touch sensing is performed at specific intervals (during designated sub-periods) rather than continuously, allowing the display to refresh at normal intervals to maintain image quality while reducing overall power consumption through selective, periodic sensing operations.
3Measurement precision
If multiple touch sensors are scanned sequentially to improve touch sensing accuracy, then measurement precision is improved, but the scanning time increases and operability is reduced
Solution Approach 1:
The patent dynamically switches between different scanning strategies based on the sensing period phase. During the first sub-period, row-by-row scanning is used for initial detection. During the second sub-period, column-by-column scanning is employed for precise measurement. This dynamic adaptation allows comprehensive sensing of multiple touch sensors with improved accuracy while maintaining fast response by utilizing parallel scanning capabilities in different phases.
Data Source
AI summary
Sensing time of a touch sensor is shortened to increase responsiveness of touch sensing. A display device includes a gate driver, a plurality of touch sensors, and a plurality of touch wirings. The gate driver has a function of supplying a scan signal to the plurality of touch wirings at the same timing, and the touch sensors in different positions sense a plurality of touches at the same timing. In this manner, the responsiveness of touch sensing is increased. The gate driver has a function of controlling a scan signal for refreshing display and a scan signal used by the touch sensor for sensing.