Multi-Modal Sensing Transducer for Curved Surface Force Detection
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Solution Overview
Problem
Conventional force sensing devices are limited to flat surfaces and face challenges when implemented on irregular or curved surfaces due to mechanical pre-load issues, requiring direct physical contact and struggling with accurate force detection.
Innovation Solution
The development of multi-modal sensing transducers that provide proximity, touch, and variable force sensing capabilities, featuring a customizable force concentrator and piezoresistive sensors, enabling operation on non-planar surfaces with reduced mechanical pre-load and the ability to detect forces without direct contact through capacitance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional force sensing devices are used on flat surfaces, then force detection is straightforward, but they cannot accurately detect forces on irregular or curved surfaces due to mechanical pre-load issues
Solution Approach 1:
The patent employs a flexible substrate that can conform to irregular and curved surfaces, replacing rigid conventional sensor housings. This flexible base layer allows the sensor to adapt to various surface geometries while maintaining accurate force detection through the piezoresistive sensing element that measures actual applied force rather than being affected by mechanical pre-load from surface conformity requirements
Solution Approach 2:
The patent replaces traditional mechanical contact-based force sensing with a multi-modal approach that includes capacitive sensing for proximity detection and piezoresistive sensing for actual force measurement. This substitution eliminates the need for direct mechanical pre-loading and contact, allowing accurate force detection on curved surfaces by measuring electrical properties that change with proximity and applied force
2Device complexity
If direct physical contact is required for force sensing, then simple sensor structure is maintained, but accurate force detection on curved surfaces becomes complex and challenging
Solution Approach 1:
The patent integrates multiple sensing modalities (capacitive proximity sensing and piezoresistive force sensing) into a single universal sensor device. The capacitive electrode detects proximity and touch without requiring direct physical contact, while the piezoresistive element measures applied force. This multi-functional approach enables the same sensor structure to work on both flat and curved surfaces without requiring direct contact for all sensing functions
Solution Approach 2:
The patent introduces a flexible substrate as an intermediary between the sensing elements and the target surface. This flexible base layer mediates the interaction by conforming to curved surfaces while transmitting force information to the piezoresistive sensor, and allowing capacitive coupling for proximity detection without requiring the sensing elements to directly contact the target surface
3Area of stationary object
If conventional force sensing is implemented on non-planar surfaces, then surface coverage is increased, but mechanical pre-load becomes undesirable and uncontrollable
Solution Approach 1:
The patent replaces mechanical pre-load-based force sensing with capacitive proximity sensing and piezoresistive force measurement. The capacitive electrode can detect proximity and touch across the entire flexible substrate surface without requiring mechanical contact or pre-load, enabling reliable wide-area sensing on curved surfaces. The piezoresistive element measures only the actual applied force perpendicular to the surface, independent of surface geometry
Solution Approach 2:
The flexible substrate acts as a conformal mounting surface that increases sensing area coverage on curved surfaces without creating unwanted mechanical pre-load. The flexibility allows the substrate to naturally conform to the surface geometry while the piezoresistive sensing measures only the differential force applied during interaction, separating the conformity function from the force measurement function
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
Enables accurate force detection and tactile feedback on curved or non-planar surfaces, enhancing applications in human-machine interfaces and safety systems by reducing mechanical pre-load and allowing nearly full surface functionality as a touch-enabled device.
Implementation Method 1
a force sensitive element including a piezoresistive sensor
Implementation Method 2
the transducer may include a capacitive sensor including an electrode
Data Source
AI summary
A multi-modal sensing transducer may include a force concentrator having an external sensing surface. The multi-modal sensing transducer may also include at least one electrode coupled to the force concentrator. Further, the multi-modal sensing transducer may include at least one force sensitive element disposed adjacent to the at least one electrode. Moreover, the multi-modal sensing transducer may include at least one air gap disposed between the at least one electrode and the at least one force sensitive element.