Dual Write Head Design for Magnetic Recording Density
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Solution Overview
Problem
Conventional magnetic recording heads face a tradeoff between linear density and track density, leading to limitations in signal-to-noise ratio and adjacent track interference, due to the curvature of track edges and the need for a strong write head, which affects the bits per track inch capability.
Innovation Solution
A dual write head design comprising a wide-writing first write head and a narrow-writing second write head, with the second write head having a curved or U-shaped surface and side shields, optimized for improved bit per inch and track per inch capabilities, and aligned with a thermal fly height control element and read heads for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a wide-writing write head is used to increase track density, then track per inch capability is improved, but linear density and signal-to-noise ratio deteriorate due to large track edge curvature
Solution Approach 1:
The patent divides the single write head into two separate write heads: a first write head with a narrow write pole for writing tracks with minimal curvature, and a second write head with a wide write pole for trimming track edges. This segmentation allows each head to be optimized for its specific function, resolving the contradiction between track width and track edge curvature.
2Force
If a strong write head is used to increase linear density, then bits per track inch capability is improved, but adjacent track interference increases
Solution Approach 1:
The patent applies local quality by giving each write head different pole widths optimized for its specific function. The first write head has a narrow pole concentrated at the center for strong field writing, while the second write head has a wide pole for distributing the field across multiple tracks for trimming. This localized optimization allows strong writing capability without excessive adjacent track interference.
3Area of moving object
If track edges have large curvature from wide-writing, then track per inch is maintained, but signal-to-noise ratio and bits per track inch are limited
Solution Approach 1:
The patent uses preliminary action by having the first write head write tracks with minimal curvature first, establishing high signal-to-noise ratio tracks. Then the second write head performs a preliminary trimming action on the track edges to maintain proper spacing. This sequence of actions ensures both high SNR and appropriate track density.
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 dual write head design increases areal density capacity by allowing random writing without track edge curvature, improving signal-to-noise ratio and bits per track inch, while maintaining track per inch capability, thus overcoming the limitations of conventional single-write head designs.
Implementation Method 1
a thermal fly height control element aligned with the second main pole of the second write head
Data Source
AI summary
The present disclosure generally relates to a magnetic media drive employing a magnetic recording head. The magnetic recording head comprises a first write head, a second write head, at least one read head, and a thermal fly height control element. The first write head is a wide writing write head comprising a first main pole and a first trailing shield. The second write head a narrow writing write head comprising a second main pole, a trailing gap, a second trailing shield, and one or more side shields. The first main pole has a shorter height and a greater width than the second main pole. The second main pole has a curved or U-shaped surface disposed adjacent to the trailing gap. The thermal fly height control element and the at least one read head are aligned with a center axis of the second main pole of the second write head.