Piezoelectric Pressing Sensor with Oblique Electrodes
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Solution Overview
Problem
Existing pressing sensors fail to accurately detect pressing operations regardless of the pressing position on the operation surface, as the warping of the surface affects potential generation, leading to reduced or reversed output.
Innovation Solution
A pressing sensor utilizing a piezoelectric film made of chiral polymer drawn in a uniaxial direction with detection electrodes arranged obliquely to the drawing direction, ensuring consistent potential generation and high sensitivity across different pressing positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the entire circumference of the operation surface is fixed to the housing, then the structure is stable, but the potential generated in the piezoelectric element may be reversed depending on the pressing position, causing the output to be reduced or reversed
Solution Approach 1:
The patent applies asymmetry by making the lateral section shape of the holding member different from the longitudinal section shape. This asymmetric configuration ensures that the operation surface warps in a controlled manner that generates potentials of the same polarity regardless of pressing position, resolving the contradiction between structural stability and measurement precision
Solution Approach 2:
The patent implements local quality by creating specific warping characteristics in different regions of the operation surface. The holding member is designed to produce consistent potential polarity in local areas across the surface, ensuring accurate pressing detection at any position while maintaining overall structural stability
2Adaptability or versatility
If the operation surface is pressed at different positions (center or end), then various warping patterns occur, but the pressing operation may not be detected accurately depending on the pressing position
Solution Approach 1:
The patent achieves universality by designing the holding member and operation surface combination to function effectively across all pressing positions. The asymmetric holding member configuration ensures that whether pressed at the center or end, the operation surface generates detectable potentials of consistent polarity, making the sensor universally responsive to pressing operations regardless of location
3Measurement precision
If electrodes are arranged to face each other obliquely to the drawing direction, then the sensitivity is high and consistent potential polarity is generated, but the electrode arrangement becomes more complex
Solution Approach 1:
The patent applies asymmetry in electrode arrangement by positioning electrodes to face each other obliquely to the uniaxial drawing direction rather than parallel or perpendicular. This asymmetric orientation optimizes the detection of shear strain in the piezoelectric film, generating consistent potential polarity across different pressing positions while maintaining a relatively simple two-electrode configuration
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 sensor effectively detects pressing operations regardless of the position, maintaining high sensitivity and accuracy by generating potentials of the same polarity at obliquely facing electrode locations, thus overcoming the limitations of existing technologies.
Implementation Method 1
a piezoelectric element may be reversed with respect to the warping of the operation surface
Data Source
AI summary
A pressing sensor includes a piezoelectric film and first and second detection electrodes. The piezoelectric film has a chiral polymer drawn at least in a uniaxial direction, and has a first main surface and a second main surface. The first and second detection electrodes are arranged on at least one of the first and second main surfaces. The first and second detection electrodes are arranged so as to face each other obliquely to the uniaxial direction.