Piezoelectric Element Corner Thickness Control
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Solution Overview
Problem
Existing piezoelectric element manufacturing methods face challenges in controlling the film thickness of the orientation control layer, leading to deteriorated piezoelectric characteristics due to either excessive thickness reducing the piezoelectric layer's thickness or inadequate coverage at corner portions, resulting in unintended crystal growth and cracks.
Innovation Solution
A manufacturing method involving the formation of a first electrode with a step region, followed by a liquid phase deposition of an orientation control layer and a piezoelectric film, which includes etching to create a piezoelectric body, ensuring uniform thickness and preventing defects at corner portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the film thickness of the orientation control layer is increased, then the coverage and uniformity of the layer is improved, but the thickness of the piezoelectric layer is reduced and piezoelectric characteristics deteriorate
Solution Approach 1:
The first electrode is designed with different thicknesses at different locations: a first thickness at the flat portion and a second thickness (greater than the first) at the corner portion. This local variation allows the orientation control layer to achieve appropriate thickness at corners while maintaining sufficient piezoelectric layer thickness at flat areas, resolving the contradiction between uniform coverage and piezoelectric performance.
2Reliability
If the film thickness of the orientation control layer is reduced, then the piezoelectric layer thickness is maintained, but the orientation control layer becomes too thin or fails to form at corner portions
Solution Approach 1:
The first electrode incorporates a corner portion with greater thickness than the flat portion, providing local reinforcement at critical areas. This ensures the orientation control layer forms completely and uniformly at corners while maintaining overall thinness to preserve piezoelectric layer thickness, eliminating formation defects without sacrificing piezoelectric performance.
3Ease of manufacture
If the orientation control layer is not formed at the corner portion of the end of the first electrode, then the film formation process is simplified, but unintended crystal growth and cracks occur in the piezoelectric layer
Solution Approach 1:
The corner portion of the first electrode is designed with greater thickness to provide adequate nucleation and growth area for the orientation control layer. This local structural feature ensures complete and uniform formation of the orientation control layer at corners, preventing unintended crystal growth and cracks while maintaining a relatively simple overall fabrication process.
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 method enhances piezoelectric characteristics by preventing defects and unintended crystal growth, resulting in a piezoelectric element with improved performance and reliability.
Implementation Method 1
forming an orientation control layer covering the first electrode by a liquid phase method
Implementation Method 2
dispenses ink droplets from the nozzle by causing a pressure change in an ink in the pressure chamber by the piezoelectric element
Data Source
AI summary
A manufacturing method of a piezoelectric element includes: forming a first conductive film on a vibration plate as a substrate; etching a first conductive film; forming a second conductive film on the first conductive film; etching the second conductive film to form a first electrode having a step region as a step formed by the second conductive film and the first conductive film at ends thereof; forming a seed layer as an orientation control layer covering the first electrode by a liquid phase method; forming a piezoelectric film on the seed layer; etching the piezoelectric film to form a piezoelectric body; and forming a second electrode covering the piezoelectric body.