Capacitive Sensor Unintentional Touch Detection
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Solution Overview
Problem
Capacitive sensors in devices often erroneously detect unintentional touches due to rain, liquids, or other capacitive objects, leading to unwanted device operations, such as volume changes or power activation, which degrade user experience and device functionality.
Innovation Solution
A system comprising electrically coupled proximity sensors forming a sensor arrangement that measures capacitance before sensing the capacitive sensor, with thresholds set to distinguish between unintentional touches and user inputs, allowing the system to skip or ignore outputs from the capacitive sensor when an unintentional touch is detected, thereby preventing erroneous device activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capacitive sensors are used to detect user touches, then device functionality can be controlled through touch input, but unintentional touches from rain or liquids cause erroneous device operations
Solution Approach 1:
The sensor system is divided into multiple independent capacitive sensors arranged in a grid pattern across the touch surface. Each sensor can be independently scanned and evaluated, allowing the system to identify localized capacitance changes from raindrops versus intentional touch patterns across multiple sensors.
Solution Approach 2:
The system performs preliminary scanning of all capacitive sensors before processing touch input. By continuously monitoring baseline capacitance values and comparing current readings against historical data, the system can pre-identify environmental conditions (such as rain or liquid presence) that may cause false touch detections, and adjust detection thresholds accordingly.
2Measurement precision
If multiple proximity sensors are added to detect unintentional touches, then false touch detection accuracy improves, but device complexity increases
Solution Approach 1:
The capacitive sensors serve dual functions: they detect both intentional user touches and unintentional touches from rain or liquids. The same sensor array and scanning circuitry are used for both purposes, eliminating the need for separate sensor systems and reducing overall device complexity while maintaining high detection accuracy.
Solution Approach 2:
The patent combines multiple capacitive sensors into a unified scanning system where a single scanning circuit iteratively measures capacitance across all sensor locations. This merged approach allows the system to process information from multiple sensors efficiently, identifying patterns that distinguish intentional touches from environmental interference without requiring separate processing circuits for each sensor.
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
Effectively prevents unwanted device operations caused by unintentional touches, improving user experience by accurately differentiating between intentional user inputs and environmental or object-induced capacitance changes, thus enhancing the reliability of capacitive touch sensing systems.
Implementation Method 1
measuring, by a scanning operation, a first capacitance of a first sensor arrangement located proximate a capacitive sensor
Data Source
AI summary
A scanning operation is performed to measure a first capacitance of a first sensor arrangement located proximate a capacitive sensor that corresponds to a function of a device. In response to the first capacitance not exceeding a first threshold, the scanning operation measures a second capacitance of the capacitive sensor to create an output used to control the function of the device. In response to the first capacitance exceeding the first threshold, operation of the scanning operation is modified to skip measuring of the second capacitance or to refrain from transmitting the output to a host of the device for controlling the function.