Capacitive Touch Panel Noise Suppression via Sampling Capacitor
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Solution Overview
Problem
Conventional capacitive touch panels integrated into display devices face challenges such as low resolution, inability to respond to small contact areas, and issues caused by parasitic capacitors and noise between the panel and the display device, limiting their effectiveness.
Innovation Solution
The integration of a capacitive touch panel with a sensing capacitor module and a sampling capacitor, coupled to a common electrode, along with a charge/discharge circuit and noise suppressing circuit, allows for accurate capacitance measurement and noise reduction, enabling improved touch detection and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a capacitive touch panel is integrated into a flat display device, then the touch panel can be incorporated into the display device, but parasitic capacitors and noises between the panel and the display device will cause problems
Solution Approach 1:
The patent extracts the harmful parasitic capacitors and noise from the system by introducing a noise suppressing circuit that separates and eliminates these interfering elements, allowing the capacitive touch panel to function properly without the harmful effects of parasitic capacitance
Solution Approach 2:
The patent introduces an intermediary noise suppressing circuit between the capacitive touch panel and the display device that acts as a mediator to filter out parasitic capacitors and noise, enabling the integration to work effectively by blocking the harmful interactions
2Adaptability or versatility
If a capacitive touch panel is used in a flat display device, then the touch panel can be integrated, but the frequency limitation prevents line-by-line scanning from being used
Solution Approach 1:
The patent applies dynamic scanning methods that adapt to the frequency limitations of the capacitive touch panel, using variable scanning rates and adaptive timing to achieve effective touch detection without requiring line-by-line scanning speeds
3Ease of operation
If a capacitive touch panel is used, then the touch panel can detect touch inputs, but it cannot provide high resolution and cannot respond to small contact areas
Solution Approach 1:
The patent divides the touch panel into multiple sensing regions and uses an array of sensing capacitors distributed across the panel, allowing each capacitor to detect touch inputs in its specific region, thereby achieving high resolution touch detection capable of identifying small contact areas like stylus tips
Solution Approach 2:
The patent implements local quality enhancement by using different sensing capacitor configurations and densities in different regions of the touch panel, optimizing the detection capability for small contact areas while maintaining overall high resolution across the entire panel surface
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 enhances the capacitive touch panel's ability to detect touch inputs with higher resolution and reduces noise interference, addressing the limitations of parasitic capacitors and noise, thereby improving the overall performance of the image display system.
Implementation Method 1
The touch panel includes a sensing capacitor module and a sampling capacitor. The sensing capacitor module is coupled to the common electrode, and the capacitance of the sensing capacitor module is variable.
Implementation Method 2
The sampling capacitor is selectively electrically connected to the sensing capacitor module and the common electrode.
Data Source
AI summary
The present invention provides an image display system including a display device. The display device further includes a capacitive touch panel and a power supply. In operation, the display device has a common electrode. The touch panel includes a sensing capacitor module and a sampling capacitor. The sensing capacitor module is connected to the common electrode, and has a variable capacitance. The sampling capacitor is selectively electrically connected to the sensing capacitor and the common electrode.