Touch Sensor Timing Controller Stylus Synchronization
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Solution Overview
Problem
Devices with touch sensors often experience touch input errors and coordinate calculation errors due to mismatched driving frequencies or cycles between the stylus pen and the display panel, particularly with passive stylus pens that cannot communicate bidirectionally.
Innovation Solution
The implementation of an electronic device with a touch sensor that includes a timing controller generating a control signal with an extended vertical blanking period, allowing the display driving period and touch sensor driving period to alternate multiple times per frame, synchronizing with the stylus pen's signal output to match its frequency, thereby improving synchronization and reducing recognition errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display panel uses a standard driving frequency, then the display performance is maintained, but touch input errors and coordinate calculation errors occur due to frequency mismatch with the stylus pen
Solution Approach 1:
The timing controller dynamically adjusts the driving frequency of the display panel to match the stylus pen's frequency. The controller detects the stylus pen's driving frequency and modifies the display panel's driving frequency accordingly, enabling adaptive frequency matching that eliminates touch input errors while maintaining display performance
Solution Approach 2:
The patent changes the driving frequency parameter of the display panel from a fixed standard value to a variable value that can be adjusted to match the stylus pen's frequency. This parameter change enables the system to adapt to different stylus pens with different frequencies, resolving the frequency mismatch problem
2Measurement precision
If the vertical blanking period is extended to allow frequency synchronization, then stylus pen recognition accuracy improves, but the display refresh rate decreases
Solution Approach 1:
The timing controller implements periodic action by alternating between display driving periods and touch sensor driving periods within each frame. The extended vertical blanking period is utilized to perform touch sensor driving at specific intervals, allowing accurate stylus pen detection without continuously interrupting the display refresh process
Solution Approach 2:
The frame period is segmented into distinct display driving periods and touch sensor driving periods. This segmentation allows the system to allocate specific time slots for stylus pen detection within the extended vertical blanking period, enabling simultaneous optimization of both recognition accuracy and display refresh rate
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively synchronizes the driving frequency of the display panel with the stylus pen's frequency, reducing touch input errors and coordinate calculation errors, enhancing the accuracy and recognition rate of stylus pen inputs.
Implementation Method 1
The timing controller, in order to synchronize with the stylus pen, generates and outputs a control signal having an extended vertical blanking period in which a vertical blanking period is extended
Implementation Method 2
When a finger or a conductive material touches (or approaches) the touch sensor, a touch screen having a capacitive touch sensor senses a touch input by sensing change in capacitance, that is, an amount of change in charge of the touch sensor
Data Source
AI summary
An electronic device having a touch sensor and a method of driving the same are disclosed. The electronic device includes a display panel having a touch screen, a touch driver configured to drive the touch screen, a timing controller configured to control the display panel and the touch driver, and a stylus pen configured to provide a signal to the touch screen. The timing controller, in order to synchronize with the stylus pen, generates and outputs a control signal having an extended vertical blanking period in which a vertical blanking period is extended, and a display driving period and a touch sensor driving period which alternate in two or more times for one frame.