Touch Panel Controller Phase-Shifted Drive Cycle
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Solution Overview
Problem
Existing touch panel systems face interference issues when the detection frame cycle of a touch sensor is shorter than the display frame cycle of a liquid crystal panel, leading to reduced touch detection accuracy and display quality, as the coincidence between display-scan and touch-detection positions cannot be adequately avoided without thinning touch detections.
Innovation Solution
A touch panel controller is designed to set the detection frame cycle to 1/n of the display frame cycle, where n is an integer, and determines the order of driving detection-scan electrodes with predetermined phase-delay and phase-advance positions relative to the display-scan electrode drive position, preventing coincidence between display-scan and touch-detection positions without thinning touch detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the detection frame cycle of the touch sensor is made shorter than the display frame cycle of the liquid crystal panel, then touch detection responsiveness is improved, but signal interference occurs between display-scan and touch-detection positions causing distorted display and reduced touch detection accuracy
Solution Approach 1:
The patent applies dynamics by making the phase difference between display-scan and touch-detection positions variable rather than fixed. The control device dynamically adjusts the phase difference based on the detection frame cycle and display frame cycle relationship, ensuring that the touch detection positions are consistently separated from display scan positions even when the detection frame cycle is shorter than the display frame cycle. This dynamic adjustment prevents signal interference while maintaining high touch detection responsiveness.
Solution Approach 2:
The patent changes the parameter of phase difference between display-scan and touch-detection positions to resolve the contradiction. By setting an appropriate phase difference based on the ratio between detection frame cycle and display frame cycle, the system ensures that touch detection positions do not coincide with display scan positions. This parameter adjustment allows the detection frame cycle to be shorter than the display frame cycle without causing signal interference, thus improving responsiveness while maintaining reliability.
2Reliability
If a fixed phase difference is set between display-scan electrode drive cycle and touch-scan electrode drive cycle, then coincidence timing can be avoided when detection frame cycle equals display frame cycle, but coincidence still occurs when detection frame cycle is shorter than display frame cycle
Solution Approach 1:
The patent transforms the static fixed phase difference approach into a dynamic adjustment mechanism. The control device calculates the appropriate phase difference based on the ratio between detection frame cycle and display frame cycle, and adjusts the touch detection position accordingly. This dynamic approach enables the system to adapt to different frame cycle ratios, including cases where the detection frame cycle is shorter than the display frame cycle, thereby preventing coincidence in all scenarios.
Solution Approach 2:
The patent changes the phase difference parameter dynamically based on the frame cycle ratio. When the detection frame cycle is shorter than the display frame cycle, the system adjusts the phase difference to ensure that touch detection positions remain separated from display scan positions. This parameter adaptation allows the system to maintain reliability across various frame cycle configurations without requiring a fixed phase difference.
3Area of stationary object
If electrodes of the touch panel are arranged to double as electrodes of the liquid crystal panel, then device size is reduced, but signal interference occurs causing distorted display and reduced touch detection accuracy
Solution Approach 1:
The patent applies dynamics by dynamically controlling the phase difference between display-scan and touch-detection positions in integrated touch panel systems. By adjusting the phase difference based on the detection frame cycle and display frame cycle relationship, the system prevents coincidence between display-scan and touch-detection positions even when sharing common electrodes. This enables size reduction through electrode integration while maintaining display quality and touch detection accuracy.
Solution Approach 2:
The patent changes the phase difference parameter to prevent signal interference in integrated electrode systems. By setting an appropriate phase difference based on frame cycle ratios, the system ensures that touch detection operations do not coincide with display scan operations on shared electrodes. This parameter adjustment allows electrode integration for size reduction while preventing the signal interference that would otherwise degrade display quality and touch detection accuracy.
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 maintains a consistent spatial distance between display-scan and touch-detection positions, preventing signal interference and enhancing touch detection accuracy while maintaining display quality, even when detection frame cycles are shorter than display frame cycles.
Implementation Method 1
a number of detection capacitances formed at intersections of the drive and detection electrodes like a matrix. Such a touch panel integrates changes in voltage arising on the detection electrodes through the detection capacitances while driving the drive electrodes sequentially, thereby forming detection signals
Implementation Method 2
In case that a finger is brought close to the detection capacitances, the stray capacitance of the finger is combined with the detection capacitances, and thus the combined capacitance values become smaller
Data Source
AI summary
The touch panel controller activates a touch panel having a detection plane superposed on a display plane of a display device, and performs a touch detection. The touch panel controller uses a cycle of 1/n (n is a positive integer) of a display frame cycle on the display plane as the detection frame cycle of the detection plane. The touch panel controller decides an order of driving the detection-scan electrodes in each detection frame cycle according to predetermined phase-delay and phase-advance positions with respect to a display-scan electrode drive position of the display device so as to correspond to an order of the detection-scan electrode array of the touch panel. The touch panel controller makes possible to avoid the coincidence of display-scan and touch-detection positions without thinning touch detections even with the detection frame cycle of a touch sensor shorter than the display frame cycle of a liquid crystal panel.