Display Touch Noise Avoidance via Dynamic Frequency Control
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Solution Overview
Problem
Noise interference from the display unit can cause touch errors in touch screen devices due to changes in capacitance between the display panel and sensing electrodes, leading to inaccurate touch position detection.
Innovation Solution
A display device with a noise analyzer that determines the frequency band of panel noise using a feedback signal and a driving frequency controller that adjusts the display driving frequency to avoid overlapping with the touch driving frequency, thereby minimizing noise interference and optimizing touch-sensing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display unit operates at a fixed display driving frequency, then the display operation is simple and stable, but noise from the display unit may interfere with touch sensing when the noise frequency coincides with the touch driving frequency
Solution Approach 1:
The display driving frequency is changed from a fixed value to a dynamically adjustable parameter. The driving frequency controller continuously monitors noise frequency information and adjusts the display driving frequency accordingly to avoid coincidence with the touch driving frequency, thereby resolving the interference problem while maintaining system reliability
Solution Approach 2:
The patent changes the operating parameter (display driving frequency) to avoid interference. By adjusting the display driving frequency based on noise frequency analysis, the system prevents noise from coinciding with the touch driving frequency, thus eliminating touch errors caused by noise interference
2Reliability
If the display driving frequency is frequently adjusted to avoid noise interference, then touch sensing accuracy is improved, but the complexity of frequency control increases
Solution Approach 1:
The system implements a feedback mechanism where noise frequency information is continuously fed back to the driving frequency controller. The controller uses this feedback to adjust the display driving frequency, ensuring that noise interference is minimized while maintaining touch sensing accuracy. This closed-loop control manages the complexity through intelligent automation
3Reliability
If noise frequency analysis is performed continuously, then the display driving frequency can be optimized to avoid interference, but the processing time and computational complexity increase
Solution Approach 1:
The system performs noise frequency analysis in advance and uses the results to pre-adjust the display driving frequency. By analyzing noise characteristics before they cause interference and proactively adjusting frequencies accordingly, the system prevents touch errors without requiring continuous real-time processing, thus reducing computational burden
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
The solution effectively reduces the impact of display unit noise on touch sensing, enhancing the accuracy and reliability of touch position detection in display devices with touch-sensing screens.
Implementation Method 1
The noise analyzer may identify the frequency band of the panel noise by performing a fast Fourier transform (FFT) computation with the feedback signal as input
Implementation Method 2
A touch screen panel may determine a touch position by sensing change in capacitance when a human hand or a stylus pen contacts sensing electrodes
Data Source
AI summary
A display device may include the following elements: a touch screen unit (or touch-sensing unit) operating with a preset touch driving frequency; a display unit operating with a display driving frequency corresponding to a driving control signal; a noise analyzer determining a frequency band of a panel noise based on a feedback signal provided from the display unit, wherein the panel noise is caused by operation of the display unit; and a driving frequency controller controlling the display driving frequency such that the frequency band of the panel noise avoids the touch driving frequency.