Adaptive Threshold Touch Sensor Circuit for Interference Mitigation
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Solution Overview
Problem
Typical mechanical switches require significant space, are structurally non-integral, prone to electric shocks, and difficult to dustproof and waterproof, while non-mechanical switches rely on physical distance changes for touch detection, leading to potential malfunctions when sensors are close.
Innovation Solution
A touch sensing device with a first and second sensor, a threshold generator, and a sensor circuit that generates differential signals based on sensing signals to determine touches by setting adaptive thresholds, allowing for independent detection of touches on separate members and preventing unintended sensing due to signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If non-mechanical switches with close sensors are used, then device size is reduced and integration is improved, but touch detection accuracy deteriorates due to signal interference between adjacent sensors
Solution Approach 1:
The patent segments the touch detection function into multiple independent sensors, each responsible for detecting touches in specific regions. By dividing the sensing area into discrete zones with dedicated sensors, the system maintains high detection accuracy even when sensors are placed close together, as each sensor operates independently with its own threshold criteria
Solution Approach 2:
The patent implements dynamic threshold adjustment where the touch detection threshold for each sensor is not fixed but adapts based on the operational state and signals from other sensors. This dynamic approach allows the system to distinguish between genuine touches and interference signals, maintaining measurement precision in compact configurations
2Reliability
If mechanical switches are used, then touch detection is reliable, but device complexity and space requirements increase
Solution Approach 1:
The patent replaces mechanical switch structures with non-mechanical touch sensors that detect touches through electrical or electromagnetic fields. This substitution eliminates moving parts, contact wear, and structural complexity while maintaining reliable touch detection, allowing for more compact and integrated device designs
3Reliability
If mechanical switches are used, then switch function is implemented, but dustproofing and waterproofing become difficult
Solution Approach 1:
The patent replaces mechanical switches with non-mechanical touch sensors that have no moving parts or openings requiring sealing. The sensors can be implemented as flat, sealed surfaces that are inherently resistant to dust and water ingress, eliminating the need for complex gaskets or seals required by mechanical switch structures
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
The solution enables a thinner, simpler, and more unified electronic device design with improved dustproofing and waterproofing, effectively preventing touch detection malfunctions between adjacent sensors by using adaptive threshold settings to accurately sense individual and simultaneous touches.
Implementation Method 1
a force sensor sensing a pressing force by using a change in resonance frequency when force is applied to surface
Implementation Method 2
a sensor (e.g., a coil) and a case (e.g., a conductor) of may become closer, which may result in an eddy current being induced in the sensor, changing, e.g., reducing, an inductance of the sensor
Data Source
AI summary
A device with touch sensing. The device includes a first sensor configured to detect a touch and to provide a first sensing signal, a second sensor configured to detect another touch and to provide a second sensing signal, a threshold generator configured to set a first threshold by a reflecting of an amount of change of the second sensing signal to an initial threshold, and a sensor circuit configured to generate a first differential signal based on the first sensing signal, and to determine a first touch based on a consideration of the first threshold with respect to a first signal generated based on the first differential signal and the first sensing signal.