Touch Detection Display Driving Circuit with Switchable Scan Speeds
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Solution Overview
Problem
In touch detection-attached display apparatuses, overtaking scan can cause disturbance in display operations due to the overlap of display and touch detection driving signals, leading to display interference.
Innovation Solution
A driving circuit and method that utilize a scan driving unit to apply display and touch detection driving signals in a time division manner with different scan speeds, where the touch detection driving signal includes a DC portion during pixel signal application and a pulse portion otherwise, ensuring the same DC potential is applied to adjacent electrodes regardless of overtaking states, thereby reducing display disturbance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the scan period of the touch detection operation is made shorter than the scan period of the display operation to enable overtaking scan, then the touch detection response speed is improved, but the display may be disturbed due to the overlap of driving signals
Solution Approach 1:
The patent divides the common electrode driving into multiple independent scanning units: display scanning units that apply display driving signals and touch detection scanning units that apply touch detection driving signals. These scanning units operate independently with different scan periods, allowing the touch detection to scan faster than the display without causing display disturbance. The segmentation of scanning functions resolves the contradiction by enabling differential scan speeds for different operations on the same electrode.
Solution Approach 2:
The patent implements dynamic switching between different scanning modes (display scanning and touch detection scanning) for the common electrode. The scanning unit can dynamically change its function and scan period based on operational requirements, allowing the system to adaptively adjust the touch detection scan speed independently of the display scan speed, thereby achieving fast touch response without display interference.
2Adaptability or versatility
If different driving signals are applied to different common electrodes to perform display and touch detection operations asynchronously, then the degree of freedom of operation is increased, but the device complexity increases
Solution Approach 1:
The patent makes the common electrode serve multiple functions: it acts as both a display driving electrode and a touch detection electrode. The same physical electrode structure is used for both display operation and touch detection operation, eliminating the need for separate electrodes and reducing device complexity while maintaining operational independence through the scanning unit architecture.
Solution Approach 2:
The scanning unit automatically manages the switching between display scanning and touch detection scanning based on internal control logic. The system self-regulates the application of different driving signals to different scanning units without requiring external complex control, thereby reducing the overall system complexity while maintaining high operational flexibility.
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 approach allows for independent and asynchronous operation of display and touch detection, reducing display interference and enabling faster touch detection response characteristics without affecting display quality.
Implementation Method 1
An electrostatic capacitance is formed between the common electrode and the touch detection electrode, so that the electrostatic capacitance is changed in response to an externally approaching object.
Data Source
AI summary
Provided is a touch-detection-function-attached display apparatus including: common-driving electrodes disposed in parallel to extend in one direction; a display device performing display based on pixel and display-driving signals; a touch-detection device detecting an externally-approaching object based on a touch-detection-driving signal; and a scan-driving unit performing a first-scan driving for sequentially-applying the display-driving signal to the common-driving electrodes in a time-division manner and a second-scan driving for sequentially-applying the touch-detection-driving signal to the common-driving electrodes in a time-division manner at a scan speed different from the first-scan-driving and applying a DC potential to the common-driving electrode which is not selected as an object of the first and second scan driving, wherein the touch-detection-driving signal includes a DC portion sustained at the DC potential in a time interval where the pixel signal is applied to the display device and a pulse portion in a time interval other than the pixel-signal-application time interval.