Piezoelectric Element Anti-Oxidation Layer Design
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Solution Overview
Problem
Existing piezoelectric actuators and ink jet recording heads face issues with the oxidation of base metal lower electrodes during the formation of piezoelectric layers, leading to detachment or cracking, which limits the freedom in selecting electrode materials.
Innovation Solution
A piezoelectric element design that includes a base metal layer with an anti-oxidation layer between the metal layer and the piezoelectric layer, and a resin layer covering the side surfaces of the first electrode, allowing the use of easily oxidizable base metals while preventing oxidation and enhancing material selection freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base metal is used for the lower electrode to reduce cost and improve electrical conductivity, then the electrical conductivity and cost-performance are improved, but the electrode oxidizes during piezoelectric layer formation causing detachment or cracking
Solution Approach 1:
An anti-oxidation layer is introduced as an intermediary between the base metal lower electrode and the piezoelectric layer. This intermediate layer prevents direct contact between the base metal and oxidizing atmosphere during piezoelectric layer formation, thereby preventing oxidation and subsequent electrode detachment or cracking while allowing the use of cost-effective base metals.
Solution Approach 2:
The lower electrode is constructed as a composite structure consisting of a base metal layer combined with an anti-oxidation layer. This composite material approach allows the base metal to provide excellent electrical conductivity and cost benefits, while the anti-oxidation layer provides protective functionality against oxidation during the manufacturing process.
2Object-affected harmful factors
If a noble metal is used for the lower electrode to prevent oxidation, then the oxidation resistance is improved, but the cost increases and electrical conductivity may be reduced
Solution Approach 1:
The anti-oxidation layer serves as a protective intermediary that eliminates the need to use noble metals for oxidation resistance. This allows designers to freely select base metals with superior electrical conductivity properties without worrying about oxidation issues, thereby restoring material selection freedom.
Solution Approach 2:
The anti-oxidation layer is applied locally only where needed - specifically on the surfaces of the lower electrode that will be exposed to oxidizing atmosphere during piezoelectric layer formation. This localized protection approach maintains the bulk properties of the base metal while providing oxidation resistance only where required.
3Ease of manufacture
If the lower electrode is exposed to oxidizing atmosphere during piezoelectric layer formation, then the piezoelectric layer can be formed properly, but the lower electrode oxidizes and expands causing detachment or cracking
Solution Approach 1:
The anti-oxidation layer acts as a protective intermediary that allows the piezoelectric layer formation process to proceed in an oxidizing atmosphere while preventing the lower electrode from oxidizing. This maintains both the ease of piezoelectric layer formation and the dimensional stability of the lower electrode.
Solution Approach 2:
The anti-oxidation layer is applied to the lower electrode surface before the piezoelectric layer formation process begins. This preliminary protective action prevents oxidation from occurring during the subsequent heating process, thereby maintaining electrode dimensional stability while allowing the piezoelectric layer to form properly.
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 design prevents oxidation of the base metal electrodes, allowing for the use of a wider range of materials and improving the reliability and stability of the piezoelectric elements and actuators, thereby enhancing their performance and manufacturing flexibility.
Implementation Method 1
the anti-oxidation layer is disposed between the metal layer and the piezoelectric layer to prevent contact between the metal layer and the piezoelectric layer
Implementation Method 2
piezoelectric actuators or ink jet recording heads can be manufactured by thin-film technology
Data Source
AI summary
A piezoelectric element includes a first electrode disposed on a substrate, a piezoelectric layer disposed on the first electrode, a second electrode disposed on the piezoelectric layer, and a resin layer that covers at least the side surfaces of the first electrode. The first electrode includes a metal layer and an anti-oxidation layer. The metal layer is formed of a base metal. The anti-oxidation layer is disposed between the metal layer and the piezoelectric layer to prevent contact between the metal layer and the piezoelectric layer.