Multi-axis Strain Sensor with Rigid Patterns
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Solution Overview
Problem
Current strain sensors are limited in their ability to precisely detect deformations in multiple directions, which are essential for capturing complex human body movements, and they often lack sensitivity and manufacturing ease.
Innovation Solution
A multi-axis strain sensor design featuring a flexible substrate with rigid patterns and a piezoresistive layer that connects electrodes, allowing for high sensitivity and directional strain detection, with the rigid patterns having greater stiffness than the substrate and piezoresistive layer, and an upper capping layer to protect the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate is used for the strain sensor, then the sensor can operate under large deformation, but the sensor lacks the ability to precisely detect deformations in multiple directions
Solution Approach 1:
The sensor is segmented into multiple independent measurement units, each equipped with rigid patterns oriented in specific directions. Each unit detects strain along its designated axis, and the combined output enables precise multi-axis strain detection while maintaining flexible substrate advantages for large deformation operation.
Solution Approach 2:
Different regions of the sensor incorporate rigid patterns with different orientations and configurations. Each local region is optimized to detect strain in a specific direction, allowing the overall sensor to capture complex multi-directional deformations with high precision while the flexible substrate provides adaptability to large deformations.
2Measurement precision
If rigid patterns are added to improve strain detection precision, then multi-axis detection capability is enhanced, but the device complexity increases
Solution Approach 1:
Multiple measurement functions are merged into a single integrated sensor structure. The rigid patterns for different measurement units are combined on the same flexible substrate, sharing common elements such as the substrate itself and signal processing circuitry, thereby reducing overall device complexity while maintaining high measurement precision.
Solution Approach 2:
The flexible substrate serves multiple functions simultaneously: it provides mechanical support, enables large deformation operation, and acts as the base for mounting rigid patterns. The rigid patterns themselves serve dual purposes by both defining measurement directions and acting as structural elements that transmit strain to the piezoresistive materials.
3Measurement precision
If rigid patterns with high stiffness are used to restrict deformation directions, then strain detection accuracy improves, but the manufacturing difficulty increases
Solution Approach 1:
The sensor utilizes thin film rigid patterns fabricated on a flexible substrate. These thin film structures can be manufactured using standard flexible electronics fabrication techniques such as screen printing, sputtering, or photolithography, making the manufacturing process relatively simple while still providing sufficient stiffness to restrict deformation directions for accurate strain 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
The sensor achieves high sensitivity and accurate detection of strain magnitude and direction, improving reliability and manufacturing simplicity while restricting deformation to specific directions, enhancing its applicability in fields like tactile sensing and human motion monitoring.
Implementation Method 1
A strain sensor, as a device made of a resistor, is attached to an object to be measured to detect a strain or a stress of the object to be measured by converting mechanical micro-deformation of the object to be measured, which is generated as a force (bending force, tensile force, and compressive force) is applied from the outside, into an electrical signal.
Data Source
AI summary
Provided is a strain sensor. The strain sensor according to embodiments of the inventive concept includes a flexible substrate, rigid patterns on the flexible substrate, the rigid patterns including a first pattern and a second pattern spaced apart from the first pattern in a first direction, a first electrode on the first pattern, a second electrode on the second pattern, the second electrode being spaced apart from the first electrode, and a piezoresistive layer connecting the first electrode and the second electrode. Here, each of the rigid patterns may have a stiffness greater than that of the flexible substrate.