Capacitive Input Interference Detection for Faster Touch Sensing
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Solution Overview
Problem
Capacitive input devices face challenges in efficiently balancing noise detection and input detection operations due to interference issues, which affect the accuracy and frame rate of sensing in capacitive input devices.
Innovation Solution
The processing system of a capacitive input device is configured to operate in two modes: a first mode for interference sensing and input sensing, and a second mode where interference sensing is reduced or omitted if interference is deemed acceptable, allowing for higher fidelity input sensing when an input object is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interference sensing is performed at a high fidelity level continuously, then interference detection accuracy is improved, but input detection speed and frame rate 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 to a second mode where interference sensing is either not performed or performed at a lower fidelity level, thereby prioritizing input detection speed while maintaining sufficient interference monitoring capability
Solution Approach 2:
The system changes the sensing parameters by switching between two distinct modes: a first mode with high fidelity interference sensing and a second mode with reduced or omitted interference sensing. This parameter change allows the system to optimize performance characteristics based on real-time operational conditions
2Measurement precision
If interference sensing is performed at high fidelity, then noise detection accuracy is improved, but time consumption increases
Solution Approach 1:
The system applies partial action by performing interference sensing at a reduced fidelity level in the second mode, or omitting interference sensing entirely when an input object is present. This partial action is sufficient for the context since the primary focus shifts to input object detection, thereby reducing time consumption while maintaining adequate noise detection capability
3Reliability
If the system operates in first mode with interference sensing, then interference detection reliability is improved, but input sensing efficiency deteriorates
Solution Approach 1:
The system dynamically switches between two operational modes based on the presence of input objects. In the second mode, when an input object is detected, the system reduces or omits interference sensing to prioritize input sensing efficiency, while maintaining the capability to switch back to high-reliability interference detection when needed
Data Source
AI summary
A processing system for a capacitive input device comprises sensor circuitry and control logic. The sensor circuitry is configured to be communicatively coupled with sensor electrodes of the capacitive input device. The control logic is configured to operate the capacitive input device 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 input device in a second mode instead of in 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 input device. While operating in the second mode, interference sensing with the capacitive input device is either not performed or else is performed at a second level that is lower in fidelity than the first level.