Piezoelectric Flexure Bonding Layout to Contain Conductive Adhesive
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Solution Overview
Problem
The bonding of piezoelectric elements to flexures in disk devices can lead to adhesive spread along the side surfaces, potentially causing electrical issues and mechanical instability.
Innovation Solution
A conductive adhesive is used to bond piezoelectric elements to flexures, with the adhesive being partially accommodated in through holes to prevent spread and maintain electrical connectivity and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive adhesive is used to bond the piezoelectric element to the flexure, then electrical connectivity is achieved, but the adhesive may spread along the side surface of the piezoelectric element causing electrical issues
Solution Approach 1:
The flexure pad is divided into a first pad and a second pad separated by a first groove. The piezoelectric element is positioned such that its side surface is exposed between these pads, creating a physical barrier that segments the adhesive spread path and prevents the conductive adhesive from reaching the side surface while maintaining electrical connectivity through the groove structure.
Solution Approach 2:
The first groove acts as an intermediary structure between the first pad and the second pad. This groove serves as a barrier that mediates the adhesive spread, allowing the conductive adhesive to bond the piezoelectric element to the flexure while preventing it from spreading along the side surface to cause electrical issues.
2Manufacturing precision
If the piezoelectric element is precisely positioned on the flexure pad, then positioning accuracy is improved, but the adhesive may still spread to unintended areas
Solution Approach 1:
The flexure pad is segmented into multiple pads (first pad, second pad, third pad) separated by grooves. This segmentation creates defined boundaries that guide the adhesive to specific bonding areas while preventing spread to unintended regions, even when the piezoelectric element is precisely positioned.
Solution Approach 2:
Different regions of the flexure pad have different properties: the first pad provides bonding surface for one electrode, the second pad for the other electrode, and the grooves provide barrier regions. This local differentiation ensures that adhesive is contained to appropriate areas while maintaining positioning accuracy.
3Object-affected harmful factors
If through holes are provided in the flexure pad to accommodate adhesive, then adhesive spread is prevented, but the structure becomes more complex
Solution Approach 1:
Instead of using complex through holes, the flexure pad is segmented into multiple pads separated by grooves. This segmentation approach contains the adhesive within defined regions without requiring through-hole drilling, maintaining structural simplicity while preventing adhesive spread.
Solution Approach 2:
The adhesive containment function is extracted from the piezoelectric element bonding interface and transferred to the flexure pad groove structure. The grooves independently perform the containment function, eliminating the need for complex through-hole structures in the element itself.
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 ensures reliable electrical connection and mechanical stability of piezoelectric elements, enhancing the performance and durability of disk devices by preventing adhesive spread and maintaining precise positioning of magnetic heads.
Implementation Method 1
The piezoelectric element works to adjust the position of the magnetic head by deforming the flexure
Data Source
AI summary
A disk device according to one embodiment includes a magnetic disk, a magnetic head, a piezoelectric element, a flexure, a first bond, and a second bond. The piezoelectric element includes a first piezoelectric body, a first electrode and a second electrode on a first surface of the first piezoelectric body, and a third electrode on a second surface of the piezoelectric body. The third electrode is connected to the second electrode. A first pad and a second pad are disposed on an outer surface of the flexure. A first through hole is open to a part of the first pad. The first electrode and the third electrode overlap with the part. The first bond joins the first pad and the first electrode together and is partly accommodated in the first through hole. The second bond joins the second pad and the second electrode together.