Magnetic Head Coil Configuration for Perpendicular Recording
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in reducing the magnetic path length while maintaining a sufficient magnetomotive force, particularly due to the need for a rapid rise in write current and higher recording densities, which is hindered by the length of the magnetic path defined by the main pole and return path section.
Innovation Solution
The magnetic head design incorporates a coil with a first and second coil portion, where the first coil portion surrounds the outer peripheral surface of a coupling section and the second coil portion surrounds the main pole, with a common portion connecting both, allowing for a shorter magnetic path and increased magnetomotive force by reducing the number of turns and optimizing the placement of the coil elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the number of turns of the coil is reduced to shorten the magnetic path, then the magnetic path length is reduced and write signal frequency can be increased, but the magnetomotive force becomes insufficient
Solution Approach 1:
The patent merges the first coil portion wound around the return path section with the second coil portion wound around the main pole into a single integrated coil structure. This allows the coil to function as both a return path coil and a main pole coil simultaneously, increasing magnetomotive force without requiring additional separate coils or increasing the number of turns, thus maintaining short magnetic path length while providing sufficient writing capability.
2Productivity
If the magnetic path length is reduced to achieve higher recording density, then recording density improves, but the coil cannot provide sufficiently large magnetomotive force
Solution Approach 1:
The patent combines the functions of the return path coil and main pole coil into a single integrated coil structure. The first coil portion is wound around the return path section while the second coil portion is wound around the main pole, and they are electrically connected to form one continuous coil. This integration allows the coil to generate strong magnetomotive force for high recording density while maintaining a short magnetic path length.
Solution Approach 2:
The integrated coil serves multiple functions simultaneously: it acts as both the return path coil and the main pole coil, providing both the magnetic flux return path and the primary writing field generation. This multi-functionality eliminates the need for separate coils and allows sufficient magnetomotive force to be generated within a compact structure suitable for high recording density applications.
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 a shorter magnetic path and a larger magnetomotive force, enhancing the ability to achieve higher recording densities and improve write characteristics, such as overwrite properties and preventing adjacent track erasure.
Implementation Method 1
The coil produces a magnetic field corresponding to data to be written on the recording medium
Implementation Method 2
The main pole passes a magnetic flux corresponding to the magnetic field produced by the coil, and produces a write magnetic field from its end face
Data Source
AI summary
A magnetic head includes a coil, a main pole and a return path section. The return path section includes a yoke section, and a coupling section coupling the yoke section to the main pole. The coil includes a first coil portion surrounding at least part of an outer peripheral surface of the coupling section, and a second coil portion surrounding at least part of the entire perimeter of the main pole as viewed from the medium facing surface. The winding of the coil includes a common portion used in common to form part of the first coil portion and part of the second coil portion.