Thin-Film Magnetic Head Leading Shield Variable Distance Structure
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Solution Overview
Problem
Conventional thin-film magnetic heads with perpendicular magnetic recording schemes face issues with heat generation leading to protrusion of the magnetic pole layer, which affects recording density and write performance due to Joule heat, and suffer from Adjacent Track Erasure (ATE) and Wide Area Track Erasure (WATE) caused by magnetic flux leakage.
Innovation Solution
A thin-film magnetic head with a leading shield part having a variable distance structure and a middle insulating layer with a variable thickness, reducing magnetic flux leakage and maintaining the shielding function while preventing data erasure, by ensuring a gap between the leading shield part and the main magnetic pole layer without decreasing its size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thin-film coil is made larger in sectional area to reduce electric resistance, then heat generation is reduced, but the magnetic path length increases making it difficult to shorten
Solution Approach 1:
The invention transitions from planar coil winding to three-dimensional coil winding that utilizes the thickness direction of the magnetic pole layer. By winding the coil in multiple layers along the thickness direction, the effective sectional area increases without extending the magnetic path length in the plane direction, thus reducing heat generation while maintaining a short magnetic path length.
Solution Approach 2:
The coil is wound in a nested multi-layer structure where inner layers are positioned closer to the magnetic pole layer and outer layers surround them. This nested arrangement increases the effective conductor cross-sectional area within a compact volume, reducing electric resistance and heat generation without increasing the magnetic path length.
2Reliability
If the leading shield part is placed close to the main magnetic pole layer, then shielding function is improved, but magnetic flux leakage occurs causing ATE and WATE
Solution Approach 1:
The leading shield part is designed with non-uniform thickness, being thicker at the rear end (远离记录面) and thinner at the front end (接近记录面). This local quality variation allows the shield to effectively block magnetic flux leakage paths while minimizing interference with the main magnetic pole layer, preventing ATE and WATE without compromising shielding function.
Solution Approach 2:
The shield structure extends in the thickness direction with varying thickness, creating a three-dimensional shielding configuration. This dimensional approach allows effective magnetic flux containment while maintaining appropriate spacing from the main magnetic pole layer, preventing flux leakage-induced erasure.
3Temperature
If the coil-insulating layer expands due to heat, then the shield layer protrudes outward, but recording precision deteriorates
Solution Approach 1:
The coil-insulating layer is designed with gradual thickness variation rather than uniform thickness. This parameter change approach allows the layer to accommodate thermal expansion more uniformly, distributing stress and preventing concentrated protrusion of the shield layer, thus maintaining position precision under thermal conditions.
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 solution effectively reduces heat generation and magnetic flux leakage, enhancing recording density and preventing data erasure, thereby improving Adjacent Track Erasure (ATE) and Wide Area Track Erasure (WATE) performance.
Implementation Method 1
the thin-film coil 602 generates heat when electric current is passed therethrough, and the heat conducts to the coil-insulating layer 605 around the thin-film coil 602
Implementation Method 2
the coil-insulating layer 605 is formed of an organic material such as photoresist or the like and is thus larger in expansion coefficient than the thin-film coil 602. For this reason, when heat is applied, the coil-insulating layer 605 is likely to expand
Implementation Method 3
Conventional thin-film magnetic heads with perpendicular magnetic recording schemes face issues with heat generation leading to protrusion of the magnetic pole layer, which affects recording density and write performance due to Joule heat
Data Source
AI summary
A thin-film magnetic head is constructed such that a main magnetic pole layer, a write shield layer, a gap layer, and a thin-film coil are laminated on a substrate. The thin-film magnetic head has a shield magnetic layer. The shield magnetic layer has a leading shield part. The leading shield part is disposed on a substrate side of the main magnetic pole layer. The leading shield part has a variable distance structure in which a rearmost part most distanced from the medium-opposing surface is distanced more from the main magnetic pole layer than is a foremost part on the main magnetic pole layer side.