Thin Film Piezoelectric Actuator Surface Roughness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current piezoelectric devices with thin sintered bulk bodies face challenges in achieving high piezoelectric performance and operational stability due to surface roughness and electric field concentration, particularly when the thickness is 10 micrometers or smaller, which affects their reliability and longevity.
Innovation Solution
A bimorph-type piezoelectric device is developed with piezoelectric films of 10 micrometers or smaller thickness and an arithmetic average surface roughness of 0.5 micrometers or smaller, utilizing vapor phase deposition and an intermediate electrode for parallel drive mode operation, eliminating the need for polarization-inversion processing and reducing electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the piezoelectric body is reduced to 10 micrometers or smaller to achieve high installation density, then the installation density is improved, but the surface roughness increases and electric field concentration occurs, degrading piezoelectric performance and reliability
Solution Approach 1:
The patent changes the surface roughness parameter from conventional levels (several micrometers) to 0.5 micrometers or smaller, and controls the thickness parameter to 10 micrometers or smaller. This parameter transformation resolves the contradiction by achieving the required thinness for high installation density while maintaining surface quality to prevent electric field concentration and ensure reliable piezoelectric performance.
2Reliability
If sintered bulk piezoelectric bodies are used to achieve high piezoelectric performance, then the piezoelectric performance is improved, but the surface roughness is great and manufacturing complexity increases
Solution Approach 1:
The patent transforms the material form from sintered bulk bodies to thin films with controlled thickness (10 micrometers or smaller) and surface roughness (0.5 micrometers or smaller). This parameter change enables high piezoelectric performance while simplifying the manufacturing process by eliminating the need for complex sintering operations and reducing the number of processing steps.
3Length of stationary object
If the thickness of the piezoelectric body is reduced to minimize thickness for high installation density, then the installation density is improved, but the grain size becomes large relative to thickness, increasing surface roughness
Solution Approach 1:
The patent simultaneously controls two parameters: thickness (10 micrometers or smaller) and surface roughness (0.5 micrometers or smaller). By transforming the material into a thin film structure with controlled surface quality, the patent resolves the contradiction between minimizing thickness and maintaining surface uniformness, ensuring that grain size does not dominate the thickness dimension.
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 solution provides high piezoelectric performance and operational stability by minimizing surface roughness and electric field concentration, enabling efficient and reliable operation of piezoelectric devices in applications like inkjet recording heads.
Implementation Method 1
the piezoelectric body expands and contracts in correspondence with increase and decrease in the strength of an electric field applied from the electrodes to the piezoelectric body
Implementation Method 2
utilizing vapor phase deposition
Data Source
AI summary
In a piezoelectric device, a first electrode, a first piezoelectric film, a second piezoelectric film, and a second electrode are formed in this order on a first electrode formed above a surface of the substrate, and an intermediate electrode is arranged between the first and second piezoelectric films. Each of the first and second piezoelectric films has a thickness of 10 micrometers or smaller, and has a first surface facing toward the substrate and a second surface opposite to the first surface. At least one of the first and second surfaces has an arithmetic average surface roughness (Ra) of 0.5 micrometers or smaller.