Flexure Protrusion Layout for Stable Piezoelectric Head Bonding
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Solution Overview
Problem
In disk devices, such as hard disk drives, the bonding material used to attach piezoelectric elements to flexures can spread unintentionally to non-corresponding electrodes, leading to potential short-circuits and unstable electrical characteristics.
Innovation Solution
The use of protrusions on the flexure surface, which are formed by bending or etching, helps to restrict the spread of conductive adhesives between electrodes, preventing them from reaching unintended areas and ensuring stable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bonding material is pressed between piezoelectric element and flexure, then bonding strength is improved, but adhesive spreads to non-corresponding electrodes causing short-circuits
Solution Approach 1:
The bonding area is segmented by introducing protrusions that divide the continuous bonding surface into separate zones. These protrusions create physical barriers that prevent the bonding material from spreading continuously across the entire flexure surface, thereby containing the adhesive within designated bonding regions while maintaining strong local bonds.
Solution Approach 2:
The protrusions act as intermediary structures between the piezoelectric element and the flexure surface. These intermediate features serve as both structural supports for positioning and as physical barriers that control the spread of bonding material, preventing direct contact between adhesive and non-corresponding electrodes.
2Area of stationary object
If bonding material is spread to ensure complete coverage, then bonding area is improved, but risk of short-circuit increases
Solution Approach 1:
Different regions of the flexure surface are given different properties through the protrusion structures. Areas with protrusions are designed to receive and contain bonding material locally, while maintaining clear boundaries. This creates zones of controlled adhesive presence versus absence, ensuring complete coverage where needed while preventing harmful spread in other regions.
Solution Approach 2:
The solution introduces a vertical dimension by adding protrusions that extend from the flexure surface. This three-dimensional feature creates height differences that physically block the bonding material from spreading laterally across the surface, effectively using the Z-dimension to control X-Y plane material distribution and prevent short-circuits.
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 solution effectively prevents short-circuits and maintains stable electrical characteristics by blocking the adhesive from spreading beyond the intended areas, ensuring reliable operation of the disk device.
Implementation Method 1
piezoelectric elements that adjust the magnetic heads in position by deforming the flexures
Implementation Method 2
The bonding material works to bond the electrodes of the piezoelectric elements and flexure pads together
Data Source
AI summary
According to one embodiment, a disk device includes a magnetic disk, a magnetic head, a flexure, a piezoelectric element, a first bonding material, a second bonding material, and a protrusion. The flexure includes a first outer surface, a first pad, and a second pad. The first pad and the second pad are on the first outer surface. The piezoelectric element includes a second outer surface, a first electrode, and a second outer surface. The first electrode and the second electrode are on the second outer surface. The first bonding material, which is conductive, bonds the first pad and the first electrode. The second bonding material, which is conductive, bonds the second pad and the second electrode. The protrusion is provided on the flexure, is located at least partially between the first bonding material and the second bonding material, and protrudes from the first outer surface.