Piezoelectric Actuator Thickness Uniformity via Inclined Substrate
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Solution Overview
Problem
The existing piezoelectric actuators face issues with uneven thickness variations in the second piezoelectric body layer, which can lead to inconsistent deformation and desired driving characteristics not being achieved.
Innovation Solution
A piezoelectric actuator design with two stacked piezoelectric body layers, where the second piezoelectric body covers at least a part of the first piezoelectric body's end surface, with specific inclination angles to minimize thickness variations and optimize deformation, using a sol-gel method for layer formation and etching to achieve uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spin coat method is used to form piezoelectric material layers, then the manufacturing process is simple and efficient, but the thickness of the piezoelectric body layers becomes uneven due to convex and concave portions on the substrate surface
Solution Approach 1:
The patent applies preliminary action by forming an inclined surface on the substrate before depositing the piezoelectric material layers. This pre-prepared surface geometry ensures that when the spin coat method is used, the material flows and distributes more uniformly, preventing thickness variations caused by subsequent convex and concave portions. The inclined surface acts as a guiding structure that directs material flow during the coating process.
Solution Approach 2:
The patent changes the geometric parameter of the substrate surface by creating an inclined surface with a specific angle range (15-45 degrees). This parameter modification fundamentally alters how the piezoelectric material distributes during the spin coating process, transforming the surface from one that creates thickness variations to one that promotes uniform deposition while maintaining manufacturing efficiency.
2Stability of the object's composition
If the second piezoelectric body layer is made thicker to cover the end surfaces, then the coverage and structural integrity are improved, but the thickness variation and deformation inconsistency worsen
Solution Approach 1:
The patent applies asymmetry by designing the second piezoelectric body layer with an inclined coverage pattern rather than a symmetric uniform thickness. The layer is thicker at certain regions to provide adequate coverage of the end surfaces while gradually thinning toward other regions. This asymmetric design ensures structural integrity where needed while maintaining overall thickness control to prevent deformation inconsistencies.
Solution Approach 2:
The patent implements local quality by varying the thickness of the second piezoelectric body layer according to the specific functional requirements of different regions. The layer provides enhanced coverage and thickness at the end surfaces where structural integrity is critical, while maintaining appropriate thickness in other regions to ensure uniform deformation characteristics. This localized quality optimization resolves the contradiction between coverage and deformation consistency.
3Ease of manufacture
If traditional etching methods are used to form piezoelectric body layers, then the process is well-established, but the end surfaces remain flat causing uneven material distribution in subsequent layers
Solution Approach 1:
The patent applies the principle of curvature by replacing the traditional flat etched surface with an inclined surface geometry. This curved/angled surface configuration fundamentally changes how subsequent material layers interact with the substrate, enabling more uniform material distribution during the spin coating process while still using conventional etching techniques to create the inclined geometry.
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 design ensures consistent and controlled deformation, maintaining desired driving characteristics and suppressing variations in the piezoelectric actuator's performance, while also reducing material costs and size.
Implementation Method 1
a first piezoelectric body arranged on one side in a thickness direction of the vibration plate; a second piezoelectric body arranged on a side, of the first piezoelectric body, which is opposite to the vibration plate in the thickness direction
Data Source
AI summary
A piezoelectric actuator includes: a vibration plate: a first piezoelectric body arranged on one side in a thickness direction of the vibration plate; a second piezoelectric body arranged on a side, of the first piezoelectric body, opposite to the vibration plate in the thickness direction; a first electrode arranged between the vibration plate and the first piezoelectric body; a second electrode arranged between the first and second piezoelectric bodies in the thickness direction, and overlapping with the first electrode in the thickness direction; and a third electrode arranged on a side, of the second piezoelectric body, opposite to the first piezoelectric body in the thickness direction, and overlapping with the second electrode in the thickness direction. The second piezoelectric body covers at least a part of a first end surface, of the first piezoelectric body, which is an end surface in a first direction orthogonal to the thickness direction.