Magnetic Head Double Bump Wrap Around Shield
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Solution Overview
Problem
Magnetic hard disk drives (HDDs) face challenges in increasing recording density due to adjacent track interference (ATI) and far track interference (FTI) caused by ineffective shielding of the main pole, leading to unintended flipping of magnetic bits in adjacent or distant tracks.
Innovation Solution
A magnetic head design featuring a main pole with side and trailing shields, where the trailing shield and side shields incorporate a multi-bump structure to effectively shunt magnetic flux, reducing interference by optimizing the write field gradient and minimizing excessive excitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the main pole is not shielded effectively, then the flux delivery to the recording medium is strong, but adjacent track interference and far track interference occur causing unintended bit flipping
Solution Approach 1:
A trailing shield is introduced as an intermediary component positioned between the main pole and the trailing side of the recording medium. This shield acts as a mediator to redirect and contain magnetic flux, preventing it from spreading to adjacent tracks and causing interference. The shield effectively blocks the harmful magnetic field propagation while allowing the main pole to maintain strong flux delivery to the intended recording location.
Solution Approach 2:
The trailing shield is designed with a non-uniform structure featuring a first portion closer to the main pole and a second portion extending further trailing. This creates local variations in shielding density and magnetic flux distribution, allowing optimal control of flux containment at different spatial locations. The differential structure enables precise management of magnetic field gradients to minimize interference while preserving write efficiency.
2Object-affected harmful factors
If the main pole is shielded with a conventional trailing shield, then adjacent track interference is reduced, but the shield excitation increases reducing write efficiency
Solution Approach 1:
The trailing shield is segmented into distinct portions: a first portion positioned closer to the main pole and a second portion extending further in the trailing direction. This segmentation allows different regions of the shield to perform specialized functions - the first portion provides primary flux containment near the pole, while the second portion extends the shielding effect further trailing. The segmented structure reduces overall shield excitation by distributing the flux management burden across multiple zones, thereby improving write efficiency while maintaining interference suppression.
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 multi-bump structure design reduces wrap-around shield excitation by approximately 20% compared to conventional designs, effectively alleviating ATI and FTI, while maintaining write efficiency, thereby enhancing recording density without compromising performance.
Implementation Method 1
the trailing shield and side shields incorporate a multi-bump structure to effectively shunt magnetic flux, reducing interference by optimizing the write field gradient
Data Source
AI summary
In one embodiment, an apparatus includes a main pole, at least one side shield positioned on sides of the main pole, and a trailing shield having a multi-bump structure positioned near a trailing side of the main pole, wherein the multi-bump structure has six junctures along the trailing shield facing the main pole, a first juncture positioned at a media-facing surface, a sixth juncture positioned away from the media-facing surface, and second, third, fourth, and fifth junctures positioned along the side of the trailing shield facing the main pole between the first and sixth juncture, wherein an element height of a first face of the trailing shield positioned between the fourth and fifth juncture is less than an element height of a second face of the trailing shield positioned at an end of the trailing shield positioned opposite the media-facing surface of the trailing shield.