Polyhedral Piezoelectric Element for Multi-Signal Touchpad Detection
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Solution Overview
Problem
Conventional piezoelectric elements can only generate a single signal in response to external mechanical pressure, limiting their reliability and utilization in sensors, actuators, transducers, and energy harvesters, as well as security touchpads like door locks.
Innovation Solution
A polyhedral piezoelectric element with multiple unit piezoelectric films forming its faces, allowing the generation of multiple electrical signals in response to a single external force by varying the poling direction and stress patterns of each film, and a touchpad design that processes these signals for enhanced security and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single piezoelectric element is used, then the structure is simple, but it can only generate one signal which limits reliability and utilization
Solution Approach 1:
The piezoelectric element is divided into multiple unit piezoelectric films (first, second, third, and fourth unit films) with different poling directions. Each unit film generates an electrical signal in response to external force, allowing multiple signals to be obtained from a single integrated element. This segmentation enables improved reliability and utilization without requiring multiple separate elements.
Solution Approach 2:
The piezoelectric element is designed to perform multiple functions simultaneously: it can detect force applied to different faces (first face, second face, third face, fourth face), generate multiple electrical signals, and provide directional information. This multi-functionality is achieved within a single element structure, improving versatility without proportionally increasing complexity.
2Reliability
If multiple unit piezoelectric films with different poling directions are integrated, then multiple signals can be generated improving reliability, but the manufacturing process becomes more complex
Solution Approach 1:
Different poling directions are established during the manufacturing process before the element is put into service. The first, second, third, and fourth unit piezoelectric films are poled in predetermined directions (first poling direction, second poling direction, third poling direction, fourth poling direction) respectively. This preliminary action of establishing poling directions during manufacturing enables the element to generate multiple distinct signals in response to force applied to different faces, improving reliability while managing manufacturing complexity through systematic pre-processing.
3Adaptability or versatility
If a polyhedral structure with multiple faces is used, then the element can detect force from multiple directions improving security level, but the shape becomes more complex
Solution Approach 1:
The piezoelectric element employs a polyhedral structure with multiple asymmetric faces (first face, second face, third face, fourth face), where each face has a specific orientation and is associated with unit piezoelectric films having distinct poling directions. This asymmetric geometric design enables the element to differentiate between forces applied to different faces, providing multi-directional detection capability and enhanced adaptability for security applications such as touchpads and door locks.
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 polyhedral piezoelectric element significantly improves the reliability and security of touchpads and other piezoelectric devices by generating multiple signals based on the face and magnitude of applied force, enhancing their operational reliability and security levels.
Implementation Method 1
When pressure (force) is applied to the piezoelectric element in a certain direction, opposite charges are induced on the first electrode and the second electrode, respectively, in response to displacement of the piezoelectric thin film due to resistance (stress) against the applied pressure, causing generation of voltage between the first electrode and the second electrode, which is called a direct piezoelectric effect.
Implementation Method 2
Conversely, voltage applied between the first electrode and the second electrode causes mechanical displacement of the piezoelectric thin film, which is called a reverse piezoelectric effect.
Data Source
AI summary
Disclosed herein are a piezoelectric element, a method of manufacturing the piezoelectric element, a touchpad including the piezoelectric element, and a method of operating the touchpad, wherein the piezoelectric element has a shape of an N-hedron and includes N polygonal unit piezoelectric films forming N faces of the N-hedron, and the touchpad includes: a first piezoelectric element having a shape of an N-hedron; a pad body having a first installation groove detachably supporting the first piezoelectric element; and a signal processer receiving and processing a first signal generated by the first piezoelectric element in response to a first external force, wherein N unit signals are generated by N unit piezoelectric films forming N faces of the first piezoelectric element in response to one external force.