Cantilevered Strain Sensor Amplifies Capacitance for Force Detection
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Solution Overview
Problem
Existing strain sensors with selective spectral responses to incident electromagnetic signals have insufficient sensitivity to detect a wide range of forces and moderate efforts effectively.
Innovation Solution
The strain sensor design includes a cantilevered portion with an anchored end and a free end, amplifying displacements and capacitance changes, allowing for enhanced detection of stress applied to the substrate, along with features like resonant frequencies, a ground plane for electromagnetic decoupling, and the absence of discrete electronic components for improved reliability and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional strain sensor design is used, then the device structure is simple, but the sensitivity is insufficient to detect moderate forces and stretches
Solution Approach 1:
The patent introduces a cantilevered portion that can dynamically deflect under applied force, transforming small substrate deformations into larger displacements of the second end. This dynamic mechanical amplification enables the sensor to detect moderate forces with high sensitivity while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent adds a vertical dimension to the sensor design by incorporating a cantilevered portion that deflects perpendicular to the substrate plane. This dimensional transformation converts in-plane substrate stretching into out-of-plane displacement, significantly amplifying the measurable signal without complicating the base structure.
2Measurement precision
If the open loop structure is used without cantilevered portion, then the device is simpler, but the displacements cannot be amplified for easy stress detection
Solution Approach 1:
The cantilevered portion acts as a dynamic amplification mechanism within the open loop structure. When force is applied to the substrate, the cantilever deflects and amplifies the displacement of the second end, enabling sensitive stress detection while preserving the simplicity of the open loop configuration.
Solution Approach 2:
The cantilevered portion serves as an intermediary mechanical element between the substrate and the second end of the open loop. It mediates the transmission of force and displacement, amplifying subtle substrate deformations into larger, more easily detectable movements without requiring complex structural modifications.
3Adaptability or versatility
If multiple conductive portions and open loops are added to detect stress direction, then the measurement capability is improved, but the device complexity increases
Solution Approach 1:
The patent implements multi-functionality by adding a third conductive portion with a second open loop that can also detect transverse direction stress. This allows the sensor to universally detect stress in multiple directions using the same cantilevered amplification mechanism, enhancing adaptability without proportionally increasing complexity.
Solution Approach 2:
The patent segments the sensing function into independent conductive portions and open loops, each capable of detecting stress in specific directions. This modular segmentation allows the addition of directional detection capabilities while maintaining clear functional separation and manageable device complexity.
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 enhanced design significantly increases sensitivity, enabling the detection of moderate and greater forces, and allows for the determination of stress direction, with improved reliability and reduced maintenance requirements.
Implementation Method 1
The first end and the second end together define a capacitor having an electrical capacitance of a value dependent on the position of the first end relative to the second end
Implementation Method 2
When a predetermined force or predetermined constraint is applied to the substrate in a longitudinal direction, there is a stretching of the substrate in the longitudinal direction
Implementation Method 3
the open loop comprises at least one cantilevered portion, extending in the longitudinal direction, which has an end of anchor bonded to the substrate, a central part not bonded to the substrate and a free end forming the second end. Thanks to these arrangements, the displacements of the cantilevered portion and in particular of the second end are amplified
Implementation Method 4
a force detection system comprising a transmitter-receiver and a stress sensor as described above, interacting through electromagnetic signals, in which said transmitter-receiver is arranged to analyze a selective spectral response from the strain sensor to the incident electromagnetic signals emitted by said transceiver
Data Source
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AI summary
The invention relates to a strain sensor (10) used as a strain gauge, which has a selective spectral response with regard to incident electromagnetic signals, including a supporting substrate (10), a first conductive portion (2), a second conductive portion comprising an open loop (3) including a first end (31) and a second end (32) arranged facing one another, together generating an electrical capacity having a value that is dependent on the position of the first end (31), wherein the open loop includes a cantilevered portion (4) which has an anchoring end (41) connected to the substrate, a central portion (43) not connected to the substrate, and a free end (32). The invention further relates to a system using such a sensor.