Recording Head Writer Protrusion and Coating Thickness
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Solution Overview
Problem
Current hard disk drives face high failure rates during single-head-stress-tests due to burnish-induced reader degradations, which are exacerbated by increased write head-media spacing when attempting to protect the reader with thicker head-overcoat, leading to reduced areal density capability.
Innovation Solution
The solution involves employing a thinner head-overcoat on the main write pole and a relatively thicker head-overcoat on the reader, with the write pole's surface protruding in front of the reader's surface, thereby reducing write head-media spacing while maintaining reader protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the head-overcoat thickness is increased to protect the reader, then reader protection is improved, but write head-media spacing increases leading to reduced areal density capability
Solution Approach 1:
The patent applies different head-overcoat thicknesses to different components: a first thickness for the reader and a second (thinner) thickness for the write pole. This local differentiation allows the reader to have enhanced protection while the write pole maintains smaller spacing to the media, resolving the contradiction between reader protection and areal density capability
Solution Approach 2:
The head assembly is segmented into distinct protective coating regions: the reader portion receives a thicker head-overcoat while the write pole portion receives a thinner head-overcoat. This segmentation enables independent optimization of protection levels for each component, allowing reader protection without compromising write spacing
2Productivity
If the write head-media spacing is reduced to improve areal density capability, then areal density capability is improved, but reader protection is reduced leading to increased failure rates
Solution Approach 1:
The patent implements location-specific head-overcoat thicknesses where the reader area receives thicker coating for protection while the write pole area uses thinner coating to enable closer spacing. This local quality differentiation resolves the contradiction by allowing each component to have the spacing/thickness appropriate for its function
Solution Approach 2:
The head-overcoat is segmented into at least two distinct thickness zones: one covering the reader with greater thickness and another covering the write pole with lesser thickness. This segmentation allows the system to achieve both reader protection and reduced write spacing simultaneously
Data Source
AI summary
An apparatus includes a recording head for reading and writing data on a data storage medium. The recording head includes a reader having a first media-confronting surface. The recording head also includes a main write pole having a second media-confronting surface that protrudes in front of the first media-confronting surface.