Perpendicular Magnetic Head Return Path Segmentation
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in producing a sufficient write magnetic field while reducing the length of the return path section, which affects recording density and write characteristics.
Innovation Solution
The magnetic head design includes first and second coils, a main pole, a write shield, a gap part, and return path sections, with the first coil wound around the coupling part and the second coil around the core part, allowing magnetic flux to pass through the main pole to produce a write magnetic field of sufficient magnitude, even with a reduced return path length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the length of the return path section is reduced, then recording density is improved, but the write magnetic field magnitude deteriorates
Solution Approach 1:
The return path section is divided into multiple segments (first return path section, second return path section, third return path section) positioned at different locations. This segmentation allows the magnetic flux to return through multiple paths, maintaining sufficient write magnetic field magnitude while reducing the overall length of any single return path segment, thereby improving recording density.
Solution Approach 2:
The return path sections are arranged in different spatial dimensions and orientations around the main pole. Instead of a single long return path, multiple shorter return paths are distributed in three-dimensional space, reducing the effective magnetic path length while maintaining the necessary magnetic flux circulation for adequate write field strength.
2Manufacturing precision
If the track width is reduced, then recording density is improved, but write characteristics deteriorate
Solution Approach 1:
The return path sections are strategically positioned at specific locations relative to the main pole and shield, creating localized magnetic flux concentration zones. This local optimization ensures that even with reduced track width, the write magnetic field is sufficiently concentrated and strong where needed, maintaining write characteristics while achieving higher recording density.
3Ease of operation
If skew is present, then head positioning is simplified, but adjacent track erasure occurs
Solution Approach 1:
The return path sections act as intermediary magnetic flux pathways that redirect and contain the magnetic flux. By providing controlled return paths, the magnetic flux is prevented from spreading laterally due to skew, thereby eliminating adjacent track erasure while maintaining the simplicity of head positioning.
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 configuration enables the main pole to generate a write magnetic field of sufficient magnitude while reducing the length of the return path section, enhancing recording density and preventing adjacent track erasure due to skew.
Implementation Method 1
first and second coils produce magnetic fields corresponding to data to be written on a recording medium
Implementation Method 2
The main pole allows magnetic fluxes corresponding to the magnetic fields produced by the first and second coils to pass, and produces a write magnetic field
Data Source
AI summary
A magnetic head includes first and second coils, a main pole, a write shield, a return path section, and a core part. The return path section includes a yoke part magnetically connected to the write shield, and a coupling part located away from a medium facing surface and magnetically coupling the yoke part and the main pole to each other. The first coil is located on the front side in the direction of travel of a recording medium relative to the main pole and wound around the coupling part. The core part is located farther from the medium facing surface than is the coupling part, and is magnetically connected to the main pole. The second coil is located on the front side in the direction of travel of the recording medium relative to the main pole and wound around the core part.