Piezoelectric Actuator Electrode Composition Against Domain Fixation
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Solution Overview
Problem
The continuous driving of piezoelectric elements in liquid ejection heads leads to domain fixation within the piezoelectric ceramic body, resulting in a decrease in displacement amount and potential driving degradation.
Innovation Solution
Incorporating a base material containing a noble metal and a dispersed metal oxide in the electrode of the piezoelectric element, with specific area ratios of the metal oxide within the base material, to increase the coercive field and reduce excessive distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the piezoelectric element is continuously driven, then the liquid ejection function is maintained, but domain fixation occurs and displacement amount decreases
Solution Approach 1:
The patent changes the material composition parameter of the electrode by incorporating metal oxide particles (such as PbO, ZnO, or TiO2) into the noble metal base material. This compositional parameter change increases the coercive field of the piezoelectric element, enabling it to resist domain fixation during continuous driving and maintain displacement performance over time.
Solution Approach 2:
The electrode is constructed as a composite material system combining a noble metal base material with dispersed metal oxide particles. This composite structure provides both the electrical conductivity of the noble metal and the field-enhancing properties of the metal oxide, resolving the contradiction between continuous operation and performance maintenance.
2Use of energy by moving object
If the electrode uses only noble metal material, then electrical conductivity is ensured, but coercive field is insufficient leading to excessive distortion
Solution Approach 1:
The electrode combines noble metal (providing electrical conductivity) with metal oxide particles (providing high coercive field). The noble metal ensures efficient electrical energy transmission to the piezoelectric ceramic, while the metal oxide particles create localized high-field regions that prevent domain fixation and reduce excessive distortion during operation.
Solution Approach 2:
The metal oxide particles are dispersed locally within the noble metal matrix, creating localized regions of high coercive field strength. This local quality enhancement allows the electrode to provide both good electrical conductivity and sufficient coercive field where needed, without compromising overall electrical performance.
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 driving degradation by minimizing domain fixation and enhancing the reliability of the piezoelectric element, ensuring consistent performance.
Implementation Method 1
the piezoelectric ceramic body, when subjected to a voltage, is displaced by moving the domain such that the c-axis is oriented in the electric field direction in the piezoelectric ceramic body, thereby generating a driving force
Implementation Method 2
the metal oxide is dispersed within the base material... to increase the coercive field and reduce excessive distortion
Data Source
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AI summary
A piezoelectric actuator includes a piezoelectric element that deforms in response to an applied voltage. The piezoelectric element includes: a piezoelectric ceramic body; and an electrode that applies a voltage to the piezoelectric ceramic body. The electrode includes: a base material containing a noble metal; and a metal oxide, and the metal oxide is dispersed within the base material.