Magnetic Head Shield Segmentation for Perpendicular Recording
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording systems face challenges in preventing adjacent track erase due to skew, where signals on adjacent tracks are erased or attenuated during writing, and existing shield configurations are inefficient in capturing magnetic flux and maintaining close proximity between main pole and return poles.
Innovation Solution
A magnetic head design featuring a shield with a bottom shield, side shields, and a top shield made of magnetic material, along with a gap part and return path sections, where the distance between the main pole and shields decreases with proximity to the substrate, allowing effective capture of magnetic flux and prevention of adjacent track erase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield is provided around the main pole to prevent adjacent track erase, then adjacent track erase is reduced, but the device complexity increases
Solution Approach 1:
The shield is divided into multiple segments: a first shield portion and a second shield portion positioned at different locations relative to the main pole. This segmentation allows each portion to independently capture magnetic flux in specific directions, effectively preventing adjacent track erase while maintaining a manageable structural complexity
Solution Approach 2:
Different portions of the shield are positioned at specific locations: the first shield portion is located at a first distance from the main pole and the second shield portion is located at a second distance from the main pole. This local differentiation optimizes the shield's ability to capture straying magnetic flux at different spatial positions, improving adjacent track protection without requiring a uniformly complex structure
2Loss of energy
If the main pole and shields are kept in close proximity to capture magnetic flux, then magnetic flux capture efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The shield portions are pre-positioned at predetermined distances from the main pole during the manufacturing process. This preliminary positioning ensures that the shields are already in optimal proximity to capture magnetic flux before the head is assembled and used, reducing the need for post-manufacturing adjustment while maintaining high magnetic flux capture efficiency
Solution Approach 2:
The shield structure is designed to create a magnetically equipotential environment around the main pole by strategically positioning shield portions at specific distances. This design equalizes the magnetic field distribution and enhances flux capture without requiring extremely tight tolerances in the positioning of individual components
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 enhanced shield configuration effectively captures magnetic flux, prevents adjacent track erase, and improves recording density by ensuring the main pole and return poles are in close proximity, thereby enhancing the write characteristics and overwrite capability.
Implementation Method 1
a coil that produces a magnetic field corresponding to data to be written on the recording medium; and a main pole that has an end face located in the medium facing surface, allows a magnetic flux corresponding to the magnetic field produced by the coil to pass, and produces a write magnetic field for writing the data on the recording medium by means of a perpendicular magnetic recording system
Implementation Method 2
a shield made of a magnetic material and having an end face that is located in the medium facing surface to wrap around the end face of the main pole
Data Source
AI summary
A magnetic head includes a shield, and first and second return path sections. The shield has an end face that is located in a medium facing surface to wrap around an end face of a main pole. The shield includes a bottom shield, two side shields, and a top shield. The first return path section is magnetically connected to the bottom shield and is greater than the bottom shield in length in a direction perpendicular to the medium facing surface. The second return path section magnetically couples the top shield and the main pole to each other. The coil includes a first portion that passes through a space defined by the main pole and the first return path section, and a second portion that passes through a space defined by the main pole and the second return path section.