Shear and Normal Force Sensor Injection Molding
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Solution Overview
Problem
Current methods for manufacturing shear and normal force sensors using polyvinylidene fluoride (PVDF) and polydimethylsiloxane (PDMS) are complex and require advanced processes like lithography and sputtering, making them difficult to produce effectively.
Innovation Solution
A method involving the fabrication of raised and sunken polymers with bent shapes, embedding a piezoelectric PVDF element between them, and incorporating a flexible printed circuit board (FPCB) for simple and efficient sensing of shear and normal forces, eliminating the need for external power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lithography and sputtering processes are used to manufacture piezoelectric force sensors, then measurement precision and sensitivity are improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent replaces complex lithography and sputtering processes with a simple mold-based injection molding process. The piezoelectric element is formed by injecting liquid polymer into a mold cavity that defines the raised and sunken patterns, eliminating the need for advanced semiconductor manufacturing equipment while maintaining sensing precision.
Solution Approach 2:
The sensor structure is divided into distinct raised portions and sunken portions that are formed separately in the mold cavity. This segmentation allows each region to be optimized for specific sensing functions (shear force in sunken regions, normal force in raised regions) while simplifying the overall manufacturing process through modular mold design.
2Measurement precision
If piezoelectric materials with high sensitivity are used, then measurement precision is improved, but manufacturing difficulty and process complexity increase
Solution Approach 1:
The patent substitutes complex material deposition processes with a straightforward injection molding technique. The piezoelectric polymer is injected in liquid form and cured in the mold, achieving high sensitivity without requiring sophisticated material processing equipment or expertise.
Solution Approach 2:
The patent changes the physical state of the piezoelectric material from solid (requiring sputtering) to liquid (amenable to injection molding). This parameter change enables simple manufacturing while maintaining the piezoelectric properties necessary for sensitive force detection.
3Manufacturing precision
If complex electrode patterns are created through sputtering, then sensing accuracy is improved, but manufacturing time and complexity increase
Solution Approach 1:
The electrode patterns and sensor geometry are pre-defined in the mold cavity structure. When the piezoelectric material is injected, the patterns are formed automatically in a single step, eliminating the need for subsequent electrode deposition processes and significantly reducing manufacturing time.
Solution Approach 2:
The patent merges the electrode pattern formation with the piezoelectric element fabrication into a single injection molding operation. The mold cavity simultaneously defines both the structural features and the electrode patterns, consolidating multiple manufacturing steps into one process.
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 the production of flexible, self-powered shear and normal force sensors that can accurately measure force magnitude and direction in real-time, with a simplified manufacturing process and improved sensitivity, suitable for wearable devices and robotic applications.
Implementation Method 1
the piezoelectric ones have an advantageous characteristic of being self-powered, i.e., generating electrical signals in response to external mechanical inputs
Data Source
AI summary
Provided are a method of manufacturing a shear and normal force sensor including fabricating raised and sunken polymers having a plurality of bent parts of bent shapes, forming an electrode pattern on one surface of a piezoelectric element, and embedding the piezoelectric element between the raised and sunken polymers, and a shear and normal force sensor including raised and sunken polymers having a plurality of bent parts of bent shapes, a piezoelectric element embedded between the raised and sunken polymers and having an electrode pattern on one surface, and a flexible printed circuit board (FPCB) embedded between the sunken polymer and the piezoelectric element and electrically connected to the electrode pattern.