Piezoelectric Element Stepped Side Surface Insulating Film Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piezoelectric elements in liquid ejection heads face issues with peeling and destruction of the insulating film due to uneven side surfaces, which can lead to gaps and cracks during manufacturing and operation.
Innovation Solution
A piezoelectric element with a side surface shaped in a stepped manner, featuring step portions with first and second side surfaces of different inclination angles, ensuring excellent coverage and adhesion of the insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the side surface of the piezoelectric layer is made uneven by wet etching to increase contact area, then adhesion between piezoelectric layer and insulating film is improved, but gaps and cracks occur during manufacturing and operation
Solution Approach 1:
The side surface of the piezoelectric layer is divided into multiple stepped surfaces rather than a single continuous surface. This segmentation creates multiple contact areas with the insulating film while maintaining proper coverage, preventing gaps and cracks that would occur with conventional uneven surfaces.
Solution Approach 2:
The side surface is transformed from a two-dimensional continuous surface into a three-dimensional stepped structure. This dimensional change allows the insulating film to properly cover each step while increasing the total contact area, simultaneously improving adhesion and maintaining manufacturing precision.
2Area of stationary object
If groove portions are formed on the side surface to increase surface area, then contact area is increased, but insulating film coverage is reduced
Solution Approach 1:
Instead of forming continuous groove portions that create shadow areas, the side surface is segmented into discrete stepped surfaces. Each step provides a contact area for the insulating film while the stepped configuration ensures the film can properly cover all surfaces without gaps.
Solution Approach 2:
Rather than forming grooves that remove material and create coverage problems, the invention inverts the approach by forming steps that add surface area in a configuration that facilitates complete insulating film coverage. The stepped structure ensures the film deposits on all surfaces without creating shadow areas.
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 stepped side surface design enhances the contact area between the piezoelectric film and the insulating film, reducing the likelihood of peeling and destruction, and maintaining the integrity of the piezoelectric element during high-voltage applications.
Implementation Method 1
a piezoelectric body, the shape of which changes when an electric field is applied
Data Source
AI summary
Provided is a piezoelectric element that includes a substrate having a lower electrode, a piezoelectric film, and an upper electrode, in that order, and an insulating film that covers at least a side surface of the piezoelectric film, wherein one of the side surfaces of the piezoelectric film has a plurality of step portions, each of the plurality of step portions has a first side surface and a second side surface, an angle of inclination of the first side surface with respect to an upper surface of the substrate is different from an angle of inclination of the second side surface with respect to the upper surface of the substrate, and an angle between the first side surface and the second side surface is 90° or more.