Piezoelectric Membrane Mixed Mode Actuation for Curvature Optimization
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Solution Overview
Problem
Existing piezoelectric membranes used in micropumps and inkjet printers exhibit non-monotonic curvature profiles, leading to counterproductive actuation when the piezoelectric material is actuated in zones of different curvature signs, limiting optimal deflection and efficiency.
Innovation Solution
A process for manufacturing membranes with optimized actuation using a mixed mode of d31 and d33 actuation in zones of different curvature, involving the determination of points of inflection to define distinct zones for perpendicular and parallel electric field applications, with structured electrodes and a stack of layers including a piezoelectric material between upper and lower electrode layers on a substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piezoelectric material is actuated uniformly across the entire membrane, then the membrane can be actuated, but the actuation becomes counterproductive in zones of different curvature signs, limiting optimal deflection
Solution Approach 1:
The membrane is divided into distinct zones (first zone and second zone) separated by a curve passing through inflection points. Each zone has different curvature characteristics and is actuated independently with appropriately signed voltages, preventing counterproductive actuation and optimizing overall deflection
Solution Approach 2:
Different actuation strategies are applied to different regions of the membrane. In the first zone, voltage is applied between upper and lower electrodes, while in the second zone, voltage is applied between upper electrodes. This local differentiation ensures that each region contributes constructively to the overall membrane deflection
2Device complexity
If the membrane operates in a single actuation mode (d31 or d33), then the structure is simpler, but the ability to optimize deflection across zones of different curvature is limited
Solution Approach 1:
The system dynamically adapts the actuation mode based on local curvature characteristics. The control system determines the curvature profile, identifies inflection points, and selectively applies d31 or d33 actuation modes in different zones, allowing the membrane to optimize its deflection response across varying curvature 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
This approach enables optimal deflection by imposing piezoelectric deformations of different signs in the membrane plane, enhancing actuation efficiency and compatibility with ferroelectric materials that can be repolarized, operating within strong electric fields without breaking.
Implementation Method 1
the piezoelectric material being previously biased with a bias voltage... the coefficients d31 and d33 correspond to the following equations, as a function of variation in deformation under the action of an electric field applied to a material with polarization P
Data Source
Figure 1~3
Figure 2a~2b
Figure 4a~4b
AI summary
The invention relates to a method for manufacturing a membrane comprising on a substrate (10) a stack of layers including at least: - a layer of piezoelectric material (30) disposed between an upper electrode layer (Esup) and a lower electrode layer (Einf) and - an elastic layer (20) supporting said piezoelectric layer, characterized in that it comprises the following steps: - the prior determination of at least one concavity/convexity curve of said membrane along an axis parallel to the plane of the layers so as to define at least one inflection point, said point allowing to isolate a first zone and a second zone corresponding to a concave part and a convex part or vice versa; - the deposition on the surface of the substrate of a stack of layers including at least one layer of piezoelectric material, a lower electrode layer, an upper electrode layer;- the structuring of at least one of the electrode layers so as to define at least said first membrane zone in which an electric field can be applied perpendicular to the plane of the layers and at least said second zone in which an electric field parallel to the plane of the layers can be applied.