Piezoelectric Actuator Insulating Layer for Strain Suppression
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Solution Overview
Problem
The existing ink-jet head designs with piezoelectric actuators suffer from unstable electric potential and strain issues due to the partial cutting of common electrodes, affecting driving stability and potentially causing unintended pressure changes in adjacent pressure chambers.
Innovation Solution
The design incorporates an insulating layer between the wiring sections and the common electrode, preventing electric field interaction with the piezoelectric layer and eliminating the need for a complex common electrode shape, thereby stabilizing the electric potential and reducing strain in the piezoelectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the common electrode is partially cut to avoid electric field interaction with wiring sections, then piezoelectric strain in adjacent areas is reduced, but the shape of the common electrode becomes complicated and electric potential stability deteriorates
Solution Approach 1:
An insulating layer is introduced as an intermediary between the wiring sections and the common electrode. This insulating layer prevents direct electric field interaction between the wiring sections and the piezoelectric layer, eliminating the need to cut the common electrode while still preventing unwanted piezoelectric strain in adjacent pressure chambers.
Solution Approach 2:
The solution segments the electric field interaction by introducing a distinct insulating layer between the wiring section and the common electrode/piezoelectric layer. This segmentation allows the common electrode to maintain its full, simple shape while still preventing harmful electric field coupling through the insulating barrier.
2Object-affected harmful factors
If the common electrode is partially cut to prevent electric field interaction, then unintended pressure changes in adjacent chambers are reduced, but driving stability deteriorates due to unstable electric potential
Solution Approach 1:
The insulating layer serves as a mediator that prevents harmful electric field interaction between wiring sections and the piezoelectric layer, thereby preventing unintended pressure changes in adjacent chambers while allowing the common electrode to maintain stable electric potential across its entire surface.
Solution Approach 2:
By segmenting the electric field paths through the insulating layer, the solution prevents harmful field coupling that causes unintended pressure changes while maintaining continuous, stable electric potential distribution across the common electrode surface.
3Reliability
If the common electrode is formed entirely on the piezoelectric layer surface, then electric potential stability is improved, but piezoelectric strain occurs in areas between individual electrodes through which wiring sections pass
Solution Approach 1:
The insulating layer is positioned between the wiring sections and the piezoelectric layer to block harmful electric field interaction. This allows the common electrode to be formed completely on the piezoelectric layer surface for stable electric potential while preventing piezoelectric strain in the areas between individual electrodes through which wiring sections pass.
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 configuration enhances the driving stability of the piezoelectric actuator by suppressing strain in the piezoelectric layer and maintaining consistent electric potential, reducing the risk of unintended pressure changes and improving the overall performance of the liquid transport apparatus.
Implementation Method 1
the electric potential is applied simultaneously to the wiring section which is connected to the individual electrode as well. As a result, the electric potential difference is generated between the wiring section and the common electrode, and the piezoelectric strain arises in the piezoelectric layer in an area which is disposed between the another individual electrodes and through which the wiring section is allowed to pass
Implementation Method 2
the piezoelectric strain arises at the portion, of the piezoelectric layer, interposed by the certain individual electrode and the common electrode. Accordingly, the vibration plate is deformed, the volume of the pressure chamber corresponding to the certain individual electrode is changed, and the pressure is applied to the ink contained in the pressure chamber
Data Source
AI summary
A piezoelectric actuator includes a vibration plate, a plurality of individual electrodes, wiring sections each extending from corresponding one of the individual electrodes and passing between the other individual electrodes other than the corresponding individual electrode, a piezoelectric layer arranged on the vibration plate to cover the individual electrodes, and a common electrode arranged on a surface of the piezoelectric layer disposed on a side opposite to the piezoelectric layer. At least portions of the plurality of wiring sections, each of which is allowed to pass between the another individual electrodes, are covered with a second insulating layer. Accordingly, it is possible to suppress the occurrence of the strain of the piezoelectric layer in the area between the individual electrodes through which the wiring section is allowed to pass, without providing any complicated shape of the common electrode in which the common electrode is partially cut out.