Piezoelectric Sensor Shielding for Noise Suppression
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Solution Overview
Problem
Piezoelectric sensors are susceptible to electromagnetic noise, which affects measurement accuracy and requires amplification to compensate, leading to potential errors in signal output before amplification.
Innovation Solution
A piezoelectric sensor design that includes a piezoelectric film with an insulating film and a signal electrode layer, an amplifier, and a shield member composed of a grounded conductor to electromagnetically shield the piezoelectric film, signal electrode layer, and amplifier, preventing electromagnetic noise from mixing with the signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic shielding is enhanced to suppress noise, then measurement precision is improved, but device complexity increases due to additional shield layers and grounding structures
Solution Approach 1:
The patent combines the shielding function with existing structural elements by making the amplifier case itself serve as the shield member. This integration eliminates the need for separate shielding layers, maintaining measurement precision through effective electromagnetic shielding while avoiding the complexity increase that would result from adding independent shielding structures.
Solution Approach 2:
The amplifier case is designed to serve dual functions: housing the amplifier and providing electromagnetic shielding. This multi-functionality approach allows the same structural element to perform both mechanical support and noise suppression roles, thereby improving measurement precision without increasing device complexity through additional components.
2Productivity
If miniaturization is pursued to reduce device size, then productivity is improved, but shielding effectiveness deteriorates due to reduced space for shield structures
Solution Approach 1:
The patent merges the shielding function into the amplifier housing structure, eliminating the need for separate shield layers that would consume additional space. This integration enables effective electromagnetic shielding to be achieved within miniaturized device dimensions, maintaining noise suppression capability while pursuing productivity improvements through compact design.
Solution Approach 2:
The amplifier case serves as a thin-walled shield structure that provides effective electromagnetic shielding without requiring thick protective layers. This approach allows miniaturization of the device while maintaining adequate shielding effectiveness, as the conductive amplifier case itself forms an effective barrier against electromagnetic noise.
3Reliability
If signal amplification is applied to compensate for weak signals, then sensitivity is improved, but noise contamination becomes more critical before amplification occurs
Solution Approach 1:
The patent applies preliminary anti-action by implementing electromagnetic shielding before the amplification process. The shield member, integrated with the amplifier case, prevents electromagnetic noise from contaminating the weak piezoelectric signals before they enter the amplifier. This preliminary protection ensures that amplification enhances sensitivity without amplifying noise, thereby maintaining measurement precision.
Solution Approach 2:
The shielding structure is established in advance of signal processing, with the amplifier case serving as the shield member before signals are amplified. This preliminary arrangement ensures that the shielding effect is already in place to protect against electromagnetic noise before the weak signals require amplification, thus preserving signal accuracy while achieving the needed sensitivity.
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 design effectively suppresses electromagnetic noise, enhancing the sensitivity and accuracy of the piezoelectric sensor by ensuring that signals are not contaminated before amplification, thereby improving measurement precision.
Implementation Method 1
a shield member which is not electrically connected to the signal electrode layer and is composed of a grounded conductor, wherein the piezoelectric film, the signal electrode layer, and the amplifier are accommodated inside the shield member
Implementation Method 2
physical signals, e.g., stress, applied to the piezoelectric device are converted to electric signals (direct piezoelectric effect) and are output from the electrodes
Implementation Method 3
electric signals input into the piezoelectric device are converted to physical signals (inverse piezoelectric effect)
Data Source
AI summary
The present disclosure provides a highly sensitive piezoelectric sensor in which mixing of electromagnetic noise into signals output from a piezoelectric device is suppressed. The present disclosure provides a piezoelectric sensor including a piezoelectric device which includes a piezoelectric film having an insulating film and a piezoelectric layer stacked on one principal surface of the insulating film and a signal electrode layer stacked on one principal surface of the piezoelectric film, an amplifier electrically connected to the signal electrode layer, and a shield member which is not electrically connected to the signal electrode layer and is composed of a grounded conductor, wherein the piezoelectric film, the signal electrode layer, and the amplifier are accommodated inside the shield member.