Piezoelectric Element Thermal Stress Compensation via Control Voltage
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Solution Overview
Problem
Piezoelectric devices with materials having different coefficients of thermal expansion experience differential expansions due to temperature changes, leading to stress and distortion in actuator displacements or sensor measurements, which existing technologies fail to effectively mitigate.
Innovation Solution
Applying a controlled electric voltage to the piezoelectric element to induce a deformation that compensates for differential thermal expansion between the piezoelectric element and the substrate, ensuring identical expansions and reducing stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the piezoelectric element is brazed or glued on a substrate made of a material different from that of the piezoelectric element, then device manufacturing flexibility is improved, but differential thermal expansion causes stresses that distort actuator displacements and sensor measurements
Solution Approach 1:
The control unit applies a compensation voltage to the piezoelectric element before or during temperature changes to preemptively counteract the differential thermal expansion stresses. This preliminary anti-action prevents the distortion from occurring in the first place, maintaining both manufacturing flexibility and measurement accuracy.
Solution Approach 2:
The system dynamically changes the electrical parameter (voltage applied to piezoelectric element) based on temperature conditions. By adjusting the voltage compensates for thermal expansion differences, allowing the use of diverse substrate materials without sacrificing precision.
2Ease of manufacture
If the piezoelectric element is brazed or glued on a substrate made of a material different from that of the piezoelectric element, then device manufacturing flexibility is improved, but differential expansions cause stresses that affect the binder layer connecting the piezoelectric element to the substrate
Solution Approach 1:
The compensation voltage counteracts thermal stresses before they can damage the binder layer, protecting the connection between piezoelectric element and substrate while allowing flexible material selection.
Solution Approach 2:
The system uses the piezoelectric element's sensitivity to stress as a beneficial feature by applying a compensating voltage that exploits the piezoelectric effect to generate counter-stresses, thereby protecting the binder layer from thermal damage.
3Adaptability or versatility
If temperature variations are significant (from −40° C. to +90° C.), then device operating range is improved, but differential expansions increase stresses that distort measurements and actuator performance
Solution Approach 1:
The control unit continuously monitors temperature and adjusts the compensation voltage accordingly, creating a feedback loop that maintains measurement accuracy across the full temperature range from -40°C to +90°C by dynamically counteracting thermal expansion effects.
Solution Approach 2:
The compensation voltage is dynamically adjusted based on real-time temperature conditions, allowing the system to adapt to significant temperature variations while maintaining precise measurements and actuator performance.
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
This method effectively cancels stress caused by differential thermal expansion, allowing for a wider selection of substrate materials and maintaining device performance across varying temperatures, thereby enhancing the reliability and accuracy of piezoelectric devices.
Implementation Method 1
subjecting the piezoelectric element to an electric voltage so determined as to cause a set deformation of the piezoelectric element
Implementation Method 2
When such a device is subjected to temperature changes, the dimensions of the substrate and the vibrating element will change differently according to the respective coefficients of thermal expansion of said materials
Data Source
AI summary
A method for controlling a piezoelectric device including a piezoelectric element attached to a substrate, with the substrate and the piezoelectric element being made of materials having different coefficients of thermal expansion includes the step of subjecting the piezoelectric element to a predetermined electric voltage in order to cause a predetermined set deformation of the piezoelectric element. The predetermined electric voltage comprises a compensation portion determined according to ambient temperature to cancel a stress generated on the piezoelectric element due to a differential thermal expansion between the piezoelectric element and the substrate.