Piezoelectric Actuator Vibration Plate Thickness Variation
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Solution Overview
Problem
The existing liquid discharging heads with piezoelectric actuators face issues of stress concentration and potential cracking due to the absence of the piezoelectric body in non-active portions, leading to reduced rigidity and performance.
Innovation Solution
The liquid discharging head design includes a piezoelectric body and vibration plate provided side by side in specific positions within the pressure chamber, with varying thicknesses to distribute stress and prevent cracking, allowing for improved rigidity and deformation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the piezoelectric body is not provided in the non-active portion, then the device complexity is reduced, but stress concentration occurs and the reliability deteriorates
Solution Approach 1:
The piezoelectric body is provided selectively in different regions: in the active portion where deflection is needed, and also in the non-active portion where stress concentration occurs. This local differentiation allows the non-active portion to have enhanced stress distribution without affecting the overall device complexity significantly.
2Reliability
If the piezoelectric body is provided in the non-active portion, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The piezoelectric body in the non-active portion is merged with the vibration plate structure, forming an integrated component. This combining approach provides stress distribution benefits while minimizing the increase in device complexity through structural integration.
3Strength
If the vibration plate thickness is increased, then the rigidity is improved, but the deformation efficiency deteriorates
Solution Approach 1:
The vibration plate is designed with non-uniform thickness: thicker in the non-active portion to provide rigidity and stress distribution, and thinner in the active portion to maintain deformation efficiency. This local quality variation allows simultaneous optimization of both rigidity and deformation efficiency.
Solution Approach 2:
The vibration plate is segmented into different thickness zones corresponding to different functional regions. The first thickness in the non-active portion and second thickness in the active portion create distinct mechanical properties in different areas, optimizing both structural strength and actuation performance.
4Power
If the vibration plate thickness is decreased, then the deformation efficiency is improved, but the rigidity deteriorates
Solution Approach 1:
The vibration plate employs local quality variation with different thicknesses in different regions. The thinner active portion ensures high deformation efficiency for ink ejection, while the thicker non-active portion maintains overall rigidity and provides stress distribution, resolving the contradiction between these two requirements.
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 reduces the occurrence of cracks and enhances the overall rigidity and deformation efficiency of the piezoelectric actuator, maintaining discharge characteristics while suppressing stress concentration.
Implementation Method 1
A liquid discharging apparatus such as a printer is provided with a liquid discharging head that changes the volume of a pressure chamber accommodating ink by a piezoelectric actuator
Data Source
AI summary
when one position where a distance in the second direction to the partition wall located at a nearest position in the second direction is long is assumed as a first position, and the other position where the distance is short is assumed as a second position, both the piezoelectric body and the vibration plate are provided at the first position and the second position, and a thickness of the vibration plate at the second position is smaller than a thickness of the vibration plate at the first position.