Multilayer Piezo Actuator Eliminating Inactive Zones
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Solution Overview
Problem
Piezo actuators with inactive zones experience mechanical stresses and poling cracks due to reduced electric field strength and insulation requirements, leading to inefficient performance and increased risk of damage.
Innovation Solution
A method to produce a fully active multilayer component by forming continuous inner electrode layers across the entire stack, eliminating inactive zones through selective electrical driving and coating of inner electrodes with functional materials, followed by curing and burn-in processes to ensure complete coverage and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inner electrode layers are set back from outer sides to provide insulation, then electrical insulation is ensured, but inactive zones are created causing mechanical stresses and poling cracks
Solution Approach 1:
The patent applies continuous inner electrode layers that extend through the entire stack without setbacks, eliminating inactive zones. This ensures continuous electrical connectivity and uniform electric field distribution across all piezoelectric layers, preventing mechanical stresses and poling cracks while maintaining reliable electrical insulation through the coating process.
Solution Approach 2:
The patent introduces a coating material applied to the outer surfaces of the stack and to the setbacks of continuous inner electrodes. This coating acts as an intermediary that provides electrical insulation between the continuous inner electrodes and the outer electrodes, eliminating the need for setback configurations and enabling fully active piezoelectric layers throughout the stack.
2Reliability
If inactive zones are created for insulation, then electrical insulation is achieved, but performance efficiency decreases due to reduced electric field strength
Solution Approach 1:
The patent implements continuous inner electrode layers that extend across the entire stack, ensuring that all piezoelectric layers are fully active with uniform electric field strength. This eliminates inactive zones and maximizes the productive response of the piezoelectric material, improving overall performance efficiency while maintaining electrical insulation through the coating material.
3Productivity
If continuous inner electrode layers are used, then inactive zones are eliminated improving performance, but electrical insulation from outer electrodes becomes challenging
Solution Approach 1:
The patent applies a coating material to the outer surfaces of the stack and to the setbacks of continuous inner electrodes. This coating material serves as an intermediary insulating layer that prevents direct electrical contact between the continuous inner electrodes and the outer electrodes, enabling the use of continuous electrode configurations while maintaining reliable electrical insulation.
Solution Approach 2:
The patent applies coating material specifically to regions where electrical insulation is required - namely the outer surfaces of the stack and the setback regions of continuous inner electrodes. This localized application of insulating material provides the necessary electrical isolation without affecting the continuous configuration of the inner electrodes in the active regions.
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 solution reduces mechanical stresses in piezoceramic materials during operation, enhancing the performance of piezo actuators by eliminating inactive zones and preventing poling cracks, thereby improving the overall efficiency and reliability of the multilayer components.
Implementation Method 1
coating of at least the electrically driven inner electrodes, or the unsintered precursors thereof, on side A with a coating material and curing
Implementation Method 2
coating of at least the electrically driven inner electrodes, or the unsintered precursors thereof, on side A with a coating material and melting
Implementation Method 3
applying a burn-in paste on sides A and C, debinding and burning the burn-in paste
Implementation Method 4
When an electric voltage is applied to the piezo element, it expands in a direction perpendicular to the generated electric field (inverse piezo effect)
Data Source
AI summary
A method of producing a fully active multilayer element including producing a fully active stack, and optionally sintering of the fully active stack or a green precursor thereof; applying outer electrodes onto sides A' and C' of the fully active stack and contacting of the uncoated inner electrodes so that the two outer electrodes electrically connect to the uncoated inner electrode layers.