Piezoelectric Device Electrode Intersection Geometry
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Solution Overview
Problem
Conduction failures often occur between the top surface and side surface electrodes in piezoelectric devices due to sharp angle shapes or burrs at the intersection points, especially when the devices are small, making it difficult to perform grinding processes.
Innovation Solution
A piezoelectric device design where the thickness ratio of the side surface electrode at its minimum point (Tb) to the top surface electrode (Tc) is maintained between 1.0 to 5.0, with a circular arc formed at the intersection to prevent conduction failures, and a production method involving an elastic body to press and form inclined parts before forming the side surface electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a machining process such as cutting or punching is performed on a large green compact to obtain multiple green piezoelectric device corresponding parts, then productivity is improved by mass production, but sharp angle shapes or burrs are generated at the intersection parts between the top surface and side surface
Solution Approach 1:
The patent applies preliminary action by forming a rounded corner part at the intersection of the top surface and side surface before depositing the side surface electrode. This preliminary shaping prevents the formation of sharp angles and burrs that would otherwise occur during machining, ensuring that the subsequent electrode deposition creates a uniform film thickness without conduction failures.
Solution Approach 2:
The patent implements spheroidality by replacing the sharp corner geometry with a rounded corner part having a specific radius of curvature. This curvature modification eliminates the geometric discontinuity that causes poor electrode adhesion and thin film formation, allowing the side surface electrode to be deposited uniformly across the entire surface including the transition zone.
2Manufacturing precision
If grinding is performed on the edge of the top surface to remove sharp angle shapes or burr, then manufacturing precision is improved, but device complexity increases and this becomes difficult for very small piezoelectric devices
Solution Approach 1:
Instead of performing corrective grinding after machining, the patent applies preliminary action by forming the rounded corner part during the initial shaping process. This prevents the need for subsequent grinding operations, simplifying the overall manufacturing process while maintaining high surface quality for electrode deposition.
Solution Approach 2:
The patent replaces the mechanical grinding process with a forming process that creates rounded corners during the initial manufacturing stage. This substitution eliminates the need for complex grinding equipment and operations, particularly benefiting very small piezoelectric devices where grinding would be extremely difficult or impossible.
3Ease of manufacture
If the side surface electrode is formed on a green piezoelectric device corresponding part with sharp angle shapes or burr, then the production process is simplified, but conduction failure occurs between the top surface electrode and side surface electrode
Solution Approach 1:
The patent applies preliminary action by pre-forming the rounded corner part before side surface electrode deposition. This ensures that when the electrode is deposited, the surface geometry allows for uniform film formation and good adhesion, preventing conduction failures while maintaining process simplicity.
Solution Approach 2:
The patent changes the geometric parameter of the intersection corner from a sharp angle to a rounded corner with a specific radius. This parameter change fundamentally alters how the electrode material deposits on the surface, ensuring continuous and uniform coverage that maintains electrical conduction reliability.
Data Source
AI summary
A plurality of piezoelectric device corresponding parts including a green main body part and a green top surface electrode formed on a top surface of the green main body part are placed on a tabular substrate at intervals. Next, a tabular elastic body is pressed from above to the plurality of piezoelectric device corresponding parts, so as to form an inclined part declined toward an outer side in an edge of a top surface of each piezoelectric device corresponding part, and to form a circular arc part at an intersection between the inclined part and a side surface of the piezoelectric device corresponding part. Next, a green side surface electrode is formed on the side surface of each piezoelectric device corresponding part so that the green side surface electrode is connected to the green top surface electrode. Next, this molded body is sintered so that a piezoelectric device is obtained.