Piezoelectric Deflection Sensor Segmented Electrode Design
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Solution Overview
Problem
Conventional piezoelectric sensors for detecting substrate deflection require measurement of both upper and lower layer outputs and necessitate a correction circuit, leading to poor detection efficiency.
Innovation Solution
A piezoelectric deflection sensor design featuring segmented electrodes on opposing surfaces of a piezoelectric plate, with external electrodes connecting opposing electrodes, and a stacked package substrate configuration to enhance detection efficiency and charge sensitivity, eliminating the need for a correction circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bimorph structure with upper and lower layer piezoelectric thin films is used to detect deflection, then the pyroelectric effect can be compensated, but the detection efficiency deteriorates due to the need to measure both outputs and provide a correction circuit
Solution Approach 1:
The piezoelectric plate is divided into multiple segments with electrodes arranged in a specific pattern (first and second electrodes on one surface, third and fourth electrodes on the opposing surface). This segmentation allows selective measurement of electrode outputs to detect deflection while inherently compensating for pyroelectric effects, eliminating the need for complex correction circuits and improving detection efficiency.
Solution Approach 2:
Instead of using a conventional bimorph structure with two separate piezoelectric layers requiring dual measurement and correction, the patent inverts the approach by using a single piezoelectric plate with strategically positioned segmented electrodes. This inversion simplifies the structure while maintaining pyroelectric compensation capability and improving detection efficiency.
2Measurement precision
If a correction circuit is provided to compensate for pyroelectric effects in conventional piezoelectric sensors, then measurement accuracy can be maintained, but the device complexity increases
Solution Approach 1:
The patent extracts the pyroelectric compensation function from the external correction circuit and integrates it into the sensor structure itself through the segmented electrode arrangement. The specific electrode configuration inherently compensates for pyroelectric effects during measurement, eliminating the need for separate correction circuits and reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The segmented electrode structure on the piezoelectric plate performs self-compensation for pyroelectric effects. The arrangement of electrodes and their connection configuration allows the sensor to automatically compensate for temperature-induced charges without requiring external correction circuits, making the system self-sufficient and simpler.
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 improves detection efficiency and charge sensitivity by efficiently transmitting stress from the substrate to the piezoelectric plate, allowing for high-capacity signal detection across a lower frequency band without the need for a correction circuit.
Implementation Method 1
a piezoelectric sensor using a d31 mode... a piezoelectric element includes the first piezoelectric plate and the first to fourth segmented electrodes
Data Source
AI summary
A piezoelectric deflection sensor includes a first piezoelectric plate having a polarization axis direction that is parallel to first and second principal surfaces, first and second segmented electrodes provided on the first principal surface of the first piezoelectric plate, and third and fourth segmented electrodes provided on the second principal surface of the first piezoelectric plate. A piezoelectric element is defined by the first piezoelectric plate and the first to fourth segmented electrodes. The first segmented electrode and the third segmented electrode oppose each other across the first piezoelectric plate, and the second segmented electrode and the fourth segmented electrode oppose each other across the first piezoelectric plate. The first segmented electrode and the fourth segmented electrode are electrically connected to each other, and the second segmented electrode and the third segmented electrode are electrically connected to each other.