Braided Piezoelectric Element with Conductive Core for Signal Stability
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Solution Overview
Problem
Existing piezoelectric elements fail to effectively extract large electrical signals from small deformations and suffer from noise issues, particularly when used in wearable devices and touch panel systems, due to the instability of braided piezoelectric fibers and difficulties in connecting terminals to conductive fibers covered with braided piezoelectric layers.
Innovation Solution
A braided piezoelectric element comprising a conductive fiber core covered with braided piezoelectric fibers, where the terminal is anchored to both the core and the conductive layer, reducing noise and stabilizing the connection, and a method to efficiently connect and disconnect multiple braids for use in wearable devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric fibers are used to extract electrical signals from small deformations, then the sensitivity to small stress is improved, but the stability and noise suppression are insufficient
Solution Approach 1:
The patent combines piezoelectric fibers with conductive fibers to form a composite structure. The piezoelectric fibers (e.g., PVDF) provide sensitivity to small deformations, while the conductive fibers (e.g., stainless steel, nickel, or conductive polymer) provide structural stability and noise suppression. This composite approach allows the piezoelectric component to detect small stresses while the conductive component maintains structural integrity and shields against electrical noise.
Solution Approach 2:
The conductive fibers act as an intermediary between the piezoelectric fibers and the external environment. They provide a stable conductive path for signal extraction while mechanically supporting the piezoelectric fibers during deformation. The conductive fibers mediate the mechanical stress distribution and electrical signal transmission, improving both stability and noise suppression without compromising the piezoelectric effect.
2Productivity
If conductive fibers are used as signal wires in piezoelectric elements, then electrical signal extraction is enabled, but noise signals increase requiring separate shielding structures
Solution Approach 1:
The patent merges the signal wire function and the noise shielding function into a single integrated structure. The conductive fibers that extract electrical signals from the piezoelectric fibers also serve as the noise shielding structure. This eliminates the need for separate shielding components while providing both signal extraction and noise suppression capabilities through the same conductive fiber network.
3Productivity
If piezoelectric sheets are used for touch panel systems, then electrical signal output by deformation is achieved, but flexibility and free bending capability are poor
Solution Approach 1:
The patent transitions from rigid piezoelectric sheets to flexible piezoelectric fibers arranged in a braided or woven structure. These fiber-based structures can be bent, stretched, and conform to various shapes while maintaining their piezoelectric properties. The flexible fiber construction enables free bending and adaptation to curved surfaces, making it suitable for wearable devices and flexible touch panels.
Solution Approach 2:
The patent segments the continuous piezoelectric sheet into discrete piezoelectric fibers. This segmentation allows the material to flex and bend more easily while maintaining structural integrity. The individual fibers can move independently during deformation, enabling the overall structure to adapt to various shapes and movements while still generating electrical signals from mechanical deformation.
4Productivity
If terminals are connected to conductive fibers covered with braided piezoelectric layers, then signal extraction is enabled, but connection stability and noise suppression are insufficient
Solution Approach 1:
The conductive fibers serve as an intermediary layer between the braided piezoelectric layers and the terminals. They provide a stable, exposed conductive path for terminal connection while the braided piezoelectric layers maintain their sensing function. This intermediary structure ensures reliable electrical connection without compromising the piezoelectric effect or noise suppression capabilities.
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 extraction of large electrical signals from small deformations while suppressing noise, allowing for efficient connection and disconnection of braided piezoelectric elements in wearable devices, enhancing their functionality and reliability.
Implementation Method 1
Piezoelectric elements using the piezoelectric effect of piezoelectric fibers are known as such types of sensors
Data Source
AI summary
Provided is a configuration capable of improving the signal strength of a piezoelectric element using piezoelectric fibers. This braided piezoelectric element comprises a core comprising conductive fibers and a sheath comprising braided piezoelectric fibers so as to cover the core, the braided piezoelectric element further comprising a metal terminal connected and fixed to the core in either of the following states A or B. A) A state where a portion of the metal terminal grasps a fiber portion constituting the end of a braided piezoelectric element and the core and the metal terminal are electrically connected to each other and fixed within 1 mm from where the metal terminal grasps the fiber portion. B) A state where: a portion of the metal terminal has a fork or needle shape; the fork-shaped or needle-shaped portion is electrically connected to the core while in contact with the sheath; and the braided piezoelectric element is secured to the metal terminal by another portion of the metal terminal or a component fixed to the metal terminal within 10 mm from the point of the electrical connection.