Capacitive Touch Screen Interference Detection Mode Switching
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Solution Overview
Problem
Capacitive touch screens face challenges in efficiently balancing noise detection and input detection operations, with existing methods either reducing frame rates or signal-to-noise ratios to detect interference, which can lead to inaccurate hypothesis testing and reduced usability.
Innovation Solution
A processing system for capacitive touch screens that operates in two modes: one for interference sensing during non-display update times and another for input object sensing, with the ability to switch between these modes based on interference conditions and input presence, allowing for efficient detection of input objects while minimizing interference detection time once an object is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interference sensing is performed continuously at high fidelity, then interference detection accuracy is improved, but frame rate and input detection speed deteriorate
Solution Approach 1:
The system dynamically adjusts the interference sensing mode based on operational context. When an input object is detected, the system switches from high-fidelity interference sensing to lower-fidelity or no interference sensing, allowing frame rate to increase while maintaining adequate interference detection capability when needed
Solution Approach 2:
The system performs interference sensing periodically rather than continuously, specifically during non-display update times. This periodic approach allows the system to maintain interference detection capability while freeing up time for input detection operations, thereby maintaining high frame rates
2Measurement precision
If interference sensing time is increased, then interference detection accuracy is improved, but input detection speed deteriorates
Solution Approach 1:
The system performs interference sensing during non-display update times, which occur periodically in the display refresh cycle. This preliminary action allows interference to be detected in advance without interfering with subsequent input detection operations, as the interference sensing is scheduled during otherwise unused time periods
Solution Approach 2:
The system dynamically adjusts interference sensing duration and fidelity based on whether an input object has been detected. When no input is present, higher-fidelity interference sensing is performed; when input is detected, the system reduces interference sensing time and switches to input detection mode
3Measurement precision
If the system operates in high-fidelity interference sensing mode, then noise detection accuracy is improved, but signal-to-noise ratio for input detection deteriorates
Solution Approach 1:
The system dynamically switches between operational modes based on detection needs. In interference sensing mode, high-fidelity noise detection is performed; when an input object is detected, the system transitions to input detection mode with lower fidelity interference sensing, thereby improving the signal-to-noise ratio for input detection
Solution Approach 2:
The system alternates between interference sensing periods and input detection periods within the display refresh cycle. During non-display update times, high-fidelity interference sensing is performed; during display update and input detection times, lower-fidelity or no interference sensing occurs, maintaining adequate signal-to-noise ratio for input detection
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 enables accurate and timely detection of input objects while maintaining high frame rates and signal-to-noise ratios, improving the overall usability and efficiency of capacitive touch screens by optimizing interference avoidance and input sensing operations.
Implementation Method 1
A processing system for a capacitive touch screen comprises sensor circuitry configured to be communicatively coupled with sensor electrodes of the capacitive touch screen
Data Source
AI summary
A processing system for a capacitive touch screen comprises sensor circuitry and control logic. The sensor circuitry is configured to communicatively couple with sensor electrodes of the capacitive touch screen. The control logic is configured to operate the capacitive touch screen in a first mode comprising interference sensing at a first level and input object sensing. The control logic is also configured to operate the capacitive touch screen in a second mode instead of the first mode in response to: interference measured in the first mode meeting an interference condition; and a determination that input is in a sensing region of the capacitive touch screen. Operating in the first mode, interference sensing is performed during a non-display update time. Operating in the second mode, interference sensing with the capacitive touch screen is either not performed or is performed at a second level, lower in fidelity than the first level.