Pressure-Activated Touch Sensor Structure for Sweat-Resistant Detection
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Solution Overview
Problem
Existing touch sensors are susceptible to interference from sweat, impurities, and human movement, and lack sufficient sensitivity for reliable human-computer interaction in wearable devices.
Innovation Solution
A touch sensor design featuring a substrate with a first electrode and a second electrode separated by an elastic layer, which remains disconnected until pressure is applied, causing the electrodes to contact and generate an electrical signal, thereby improving sensitivity and stability by adjusting the distance between the electrodes and using a protective layer for encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing touch sensors are used, then basic touch detection is possible, but they are susceptible to interference from sweat, impurities, and human movement, and lack sufficient sensitivity
Solution Approach 1:
The patent introduces an elastic layer as an intermediary between the first and second electrodes. This elastic layer acts as a mediator that transmits mechanical pressure from the touch surface to the electrodes while isolating them from direct contact with interfering substances like sweat and impurities. The elastic layer deforms under pressure to close the circuit between electrodes, providing reliable touch detection without being affected by the harmful factors present in the environment.
Solution Approach 2:
The patent replaces traditional capacitive or resistive touch sensing mechanisms with a mechanical pressure-based switching system. Instead of detecting changes in electrical properties caused by human capacitance or moisture, the system uses mechanical pressure to deform the elastic layer and directly close the electrical circuit between electrodes. This mechanical substitution eliminates sensitivity to electromagnetic interference and environmental factors while maintaining high touch detection sensitivity.
2Measurement precision
If the distance between electrodes is reduced to improve sensitivity, then touch detection becomes more sensitive, but the sensor becomes more susceptible to false triggering from minor movements or contaminants
Solution Approach 1:
The elastic layer serves as a controlled intermediary that manages the distance between electrodes. It allows the electrodes to be positioned close together for high sensitivity while preventing direct contact or false triggering from minor contaminants. The elastic layer's mechanical properties ensure that only sufficient pressure from intentional touch gestures can close the circuit, filtering out false triggers from minor movements or impurities.
Solution Approach 2:
The patent utilizes the elastic layer's deformable parameter to dynamically adjust the electrode distance. In the resting state, the elastic layer maintains a small but sufficient gap between electrodes for high sensitivity. When touch pressure is applied, the elastic layer deforms to close the gap and trigger the circuit. This parameter change approach allows the system to optimize both sensitivity and false trigger resistance through controlled mechanical deformation rather than fixed electrode spacing.
3Object-affected harmful factors
If a protective layer is added to encapsulate the sensor components, then resistance to sweat and impurities is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The elastic layer performs multiple functions simultaneously: it serves as a protective barrier against sweat and impurities, acts as a mechanical transmitter to close the circuit under pressure, and provides structural support for the second electrode. By combining protection and functionality in a single component, the design avoids adding separate protective layers that would increase complexity, achieving both contamination resistance and operational functionality without excessive structural complexity.
Solution Approach 2:
The patent employs a thin elastic layer as a flexible protective film that encapsulates the electrode interface. This thin film approach provides effective protection against sweat and impurities while minimizing the addition of structural complexity. The flexible nature of the elastic layer allows it to conform to the touch surface and transmit pressure effectively, maintaining sensor functionality while providing environmental protection without requiring complex multi-layer encapsulation 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 touch sensor effectively filters out interference from human capacitance, sweat, and movement, providing high sensitivity and stability, and allows for accurate determination of touch gestures, enhancing the reliability of human-computer interaction in wearable devices.
Implementation Method 1
when a user applies a pressure to the touch sensor, the elastic layer deforms, the first electrode comes into contact with the second electrode
Data Source
AI summary
Embodiments of the present disclosure relate to a touch sensor. The touch sensor includes: a substrate; a first electrode and a second electrode, the first electrode being disposed on the substrate; and an elastic layer disposed on the first electrode or the substrate, the second electrode being disposed on the elastic layer. When the elastic layer is in a natural state, the first electrode and the second electrode are not in contact, and the touch sensor is in a disconnected state; and when a user applies a pressure to the touch sensor, the elastic layer deforms, the first electrode comes into contact with the second electrode, and the touch sensor switches from the disconnected state to a connected state and generates an electrical signal.