Curved Piezoelectric Membrane Grain Alignment
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Solution Overview
Problem
Conventional methods for forming curved piezoelectric membranes in MEMS actuators result in misaligned grain structures, leading to high internal stress and reduced actuator lifespan, particularly when printing at lower resolutions where larger droplet volumes are required.
Innovation Solution
A process involving a profile-transferring substrate with a curved surface surrounded by a planar surface is used to deposit piezoelectric material, resulting in aligned columnar grains perpendicular to the surface, reducing internal stress and enhancing deflection efficiency and actuator longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional methods are used to form curved piezoelectric membranes, then the membrane can be formed with a curved shape, but the grain structures become misaligned leading to high internal stress and reduced actuator lifespan
Solution Approach 1:
A profile-transferring substrate with a pre-formed curved surface is used before depositing the piezoelectric material. This preliminary preparation of the substrate surface ensures that the piezoelectric layer is deposited on a curved surface from the beginning, allowing grain structures to align perpendicular to the curved surface during deposition, thereby reducing internal stress while maintaining the curved shape.
Solution Approach 2:
The profile-transferring substrate acts as an intermediary tool that temporarily provides the curved surface geometry during the deposition process. After the piezoelectric layer is deposited with proper grain alignment on the curved surface, the profile-transferring substrate is removed, leaving the curved piezoelectric membrane with aligned grain structures and reduced internal stress.
2Area of stationary object
If the printhead module is made smaller to reduce footprint, then the device size is reduced, but the actuators can only eject smaller drops which limits printing resolution flexibility
Solution Approach 1:
The piezoelectric membrane is formed with a curved shape (convex or concave) rather than being flat. This curvature increases the surface area and volume displacement capability of the membrane within a smaller footprint, enabling the actuator to eject larger droplets while maintaining a compact printhead design, thus providing flexibility for both high and low resolution printing.
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 process produces piezoelectric membranes with improved deflection efficiency and extended lifespan, capable of handling higher volume displacement while maintaining a smaller footprint, suitable for both high and low printing resolutions.
Implementation Method 1
The piezoelectric actuator includes a layer of piezoelectric material that changes geometry (or actuates) in response to a voltage applied across the piezoelectric layer by a pair of opposing electrodes
Implementation Method 2
The piezoelectric material used for the piezoelectric actuator is deposited on at least the curved surface of the profile-transferring substrate
Data Source
AI summary
Processes for forming an actuator having a curved piezoelectric membrane are disclosed. The processes utilize a profile-transferring substrate having a curved surface surrounded by a planar surface to form the curved piezoelectric membrane. The piezoelectric material used for the piezoelectric actuator is deposited on at least the curved surface of the profile-transferring substrate before the profile-transferring substrate is removed from the underside of the curved piezoelectric membrane. The resulting curved piezoelectric membrane includes grain structures that are columnar and aligned, and all or substantially all of the columnar grains are locally perpendicular to the curved surface of the piezoelectric membrane.