Capacitive Touch Screen Noise Detection via Electrode Isolation
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Solution Overview
Problem
Capacitive touch screen panels face performance degradation due to outside noise, which affects their ability to accurately sense user inputs, as their reception sensitivity is often insufficient to detect and distinguish spurious external signals effectively.
Innovation Solution
The touch screen panel incorporates a controller that selectively cuts off electrical connections between driving and sensing electrodes during a noise measuring mode to enhance the reception sensitivity of external noise, using switches to isolate specific electrodes and maintain connections only where necessary, allowing for improved noise detection without interfering with touch recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch screen panel operates in normal touch recognition mode with all electrical connections maintained, then touch input detection function is preserved, but reception sensitivity to outside noise remains too low to detect spurious external signals effectively
Solution Approach 1:
The patent implements dynamic switching between different electrical connection states through control signals. The controller selectively connects or disconnects driving electrodes and sensing electrodes based on operational mode (noise measurement vs. touch recognition), enabling the system to adapt its sensitivity characteristics dynamically without permanent structural changes
Solution Approach 2:
The patent segments the electrical connection control by individually managing connections for different driving electrodes and sensing electrodes. By selectively disconnecting specific driving electrodes while maintaining sensing electrode connections, the system can isolate noise signals from specific regions without completely disabling touch recognition functionality
2Measurement precision
If switches are introduced to selectively cut off electrical connections for noise measurement, then reception sensitivity to outside noise is enhanced, but device complexity increases
Solution Approach 1:
The patent makes the existing driver and controller circuits multi-functional by enabling them to perform both normal touch recognition operations and noise measurement operations. The same sensing electrodes and driver circuits are reused in both modes, with the switches serving dual purposes of mode selection and signal isolation, thereby reducing the need for separate dedicated noise measurement hardware
3Measurement precision
If electrical connection is cut off between driving electrodes and driver during noise measurement, then outside noise reception sensitivity is increased, but touch recognition mode operation is disrupted
Solution Approach 1:
The patent implements periodic alternation between noise measurement mode and touch recognition mode through controlled switching. The system can periodically disconnect driving electrode connections to measure noise, then restore connections for touch recognition, enabling both functions to operate in sequence without permanent disruption to either capability
Data Source
Figure 1A~1B
Figure 1C~2A
Figure 2B~2C
AI summary
A touch screen panel includes a plurality of driving electrodes, a plurality of sensing electrodes crossing the driving electrodes, a driver for supplying a driving signal to the driving electrodes in a touch recognizing mode, and a controller for receiving signals from the sensing electrodes. In a noise measuring mode, the controller is configured to cut off an electrical connection between one of the driving electrodes and the driver or between one of the sensing electrodes and the controller, maintain an electrical connection between another one of the sensing electrodes and the controller, and detect a noise signal from the other one of the sensing electrodes. The touch screen panel and a driving method of the touch screen panel can increase or maximize the reception sensitivity of outside noise.