Piezoelectric Actuator Bowing Control via Parallel Films
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Solution Overview
Problem
Conventional piezoelectric actuators experience bowing due to stress and temperature changes, leading to operational issues, as they are formed by layering different materials which cause deformation and affect their performance.
Innovation Solution
A switching apparatus is designed with a first piezoelectric film that expands and contracts under drive voltage, and a second piezoelectric film provided in parallel to restrict bowing when voltage is not applied, using perovskite ferroelectric substances like PZT, which are deposited symmetrically to manage stress and thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single piezoelectric film is used to form the actuator, then the actuator can be driven by voltage to change shape, but bowing occurs due to stress and temperature changes
Solution Approach 1:
The actuator is segmented into multiple piezoelectric films (first and second piezoelectric films) with different functional roles. The first piezoelectric film is responsible for drive-induced shape change, while the second piezoelectric film compensates for bowing, dividing the overall function into specialized sub-functions that resolve the contradiction between drive capability and stability.
Solution Approach 2:
The actuator uses a composite structure of multiple piezoelectric films layered together. This composite material approach allows combining the piezoelectric properties needed for actuation with additional films that provide stress compensation and thermal stability, enabling both drive capability and bowing reduction.
2Ease of operation
If different materials are layered to form the piezoelectric actuator, then the actuator can function, but bowing occurs due to stress between layers
Solution Approach 1:
Different regions of the actuator structure have different local qualities - the first piezoelectric film is optimized for piezoelectric actuation while the second piezoelectric film is optimized for stress compensation. This local differentiation allows each layer to perform its specific function, resolving the contradiction between operational functionality and manufacturing precision.
3Adaptability or versatility
If the ambient temperature changes, then the actuator operates in different environments, but the bowing amount changes making proper operation difficult
Solution Approach 1:
The actuator design changes the physical parameters of the structure by adding a second piezoelectric film that specifically addresses thermal expansion and contraction effects. This parameter modification enables the actuator to maintain stable operation across a wider temperature range by compensating for thermal-induced bowing.
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 effectively reduces bowing and maintains operational stability across varying temperatures, enabling reliable switching and testing in a wide range of environments with reduced power consumption.
Implementation Method 1
a first piezoelectric film that expands and contracts according to a drive voltage to change a bowing amount of the actuator
Implementation Method 2
a second piezoelectric film that is provided in parallel with the first piezoelectric film and restricts bowing of the actuator when the drive voltage is not being supplied to the first piezoelectric film
Data Source
AI summary
To restrict a bowing amount of a piezoelectric actuator, provided is a switching apparatus comprising a contact point section including a first contact point; and an actuator that moves a second contact point to contact or move away from the first contact point. The actuator includes a first piezoelectric film that expands and contracts according to a drive voltage to change a bowing amount of the actuator, and a second piezoelectric film that is provided in parallel with the first piezoelectric film and restricts bowing of the actuator when the drive voltage is not being supplied to the first piezoelectric film.