Piezoelectric Actuator with Segmented Electrode Strain Gauge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piezoelectric actuator devices face challenges in integrating deflection measurement and actuation without increasing production complexity or cost, as the surface area for measurement competes with actuation, and current solutions like piezoresistive gauges are sensitive to temperature and require costly manufacturing steps.
Innovation Solution
A piezoelectric actuation structure that incorporates a piezoresistive strain gauge produced within the electrode layers, allowing for complete integration of actuation and measurement without additional technological steps, using photolithography to define the gauge within the electrode layers, thereby maximizing actuation surface area without degrading deflection measurement zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the surface area of the electrode is increased to maximize charge recovery, then the measurement sensitivity is improved, but the actuation surface area is reduced
Solution Approach 1:
The electrode is segmented into two distinct functional zones: a first electrode area dedicated to actuation and a second electrode area dedicated to measurement. This segmentation allows each zone to be optimized for its specific function without compromising the other, resolving the contradiction between measurement sensitivity and actuation surface area.
Solution Approach 2:
Different regions of the electrode are assigned different qualities and functions. The first electrode area is optimized for actuation with appropriate material properties and geometry, while the second electrode area is optimized for measurement with high sensitivity characteristics. This local differentiation enables both functions to perform optimally simultaneously.
2Measurement precision
If piezoresistive gauges based on p-doped silicon are used to achieve high gauge factors, then measurement sensitivity is improved, but temperature sensitivity and manufacturing complexity increase
Solution Approach 1:
The patent replaces expensive, complex-to-manufacture p-doped silicon piezoresistive gauges with a simpler metallic or conductive material-based electrode that serves both actuation and measurement functions. This substitution reduces manufacturing complexity and cost while maintaining adequate measurement sensitivity through the segmented electrode design.
Solution Approach 2:
The electrode is designed to serve multiple functions: it acts as both the actuation element (first electrode area) and the measurement sensor (second electrode area). This multi-functionality eliminates the need for separate piezoresistive gauge structures and their associated complex manufacturing processes, thereby reducing device complexity while maintaining measurement capability.
3Reliability
If separate zones for actuation and measurement are created, then each function can be optimized, but device integration and production simplicity are reduced
Solution Approach 1:
The patent merges the actuation function and measurement function into a single integrated electrode structure. The segmented electrode areas are formed as part of the same fabrication process sequence, combining multiple functions into one component without requiring separate manufacturing steps for actuation and sensor elements, thus maintaining production simplicity.
Solution Approach 2:
The segmented electrode structure is designed and fabricated in advance during the standard piezoelectric actuator manufacturing process. The division into first and second electrode areas is established during initial fabrication steps, allowing both actuation and measurement functions to be pre-integrated before final assembly, thereby maintaining ease of manufacture while achieving functional optimization.
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
Enables the production of completely integrated devices with enhanced sensitivity and reduced thermal noise, achieving precision comparable to optical measurements without additional cost or complexity, by utilizing a strain gauge integrated into the electrode layers.
Implementation Method 1
a layer of piezoelectric material (42) arranged between a lower electrode layer (43) and an upper electrode layer (44)
Implementation Method 2
at least one piezoresistive strain gauge (44j) produced in the same layer as the upper and/or lower electrode layer
Data Source
Figure 1~2
Figure 3~4a
Figure 4b~4c
AI summary
The invention relates to a piezoelectric actuation structure comprising at least one strain gauge and at least one actuator made from a stack on the surface of a support of at least one layer of piezoelectric material (42) arranged between a lower electrode layer (43) and an upper electrode layer (44), at least a portion of the stack forming the actuator being arranged above a cavity formed in the support characterized in that the strain gauge is a piezoresistive gauge located in the upper electrode layer and/or the lower electrode layer (44j, 43/44j), said layer(s) having electrode discontinuities allowing the piezoresistive gauge to be made. The invention also relates to a method for manufacturing such a structure.