Thin-Film Magnetic Head Coil Relocation for Resistance Reduction
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Solution Overview
Problem
Conventional thin-film magnetic heads face challenges in reducing the electric resistance of the thin-film coil within the restricted read/write separation range without increasing the magnetic path length, leading to protrusion issues that affect recording density and head stability.
Innovation Solution
A thin-film magnetic head design where the main magnetic pole layer, write shield layer, and thin-film coil are laminated on a substrate, with a leading shield part and substrate side coil layer configuration that equalizes the space between the lower and upper end faces, allowing for reduced read/write separation and increased coil height without gaps, thereby decreasing electric resistance and magnetic path length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thin-film coil is made thicker to reduce electric resistance, then the electric resistance decreases, but the read/write separation increases beyond the allowed range
Solution Approach 1:
The patent repositions the thin-film coil from a location between the main magnetic pole layer and the reproducing head to a location between the main magnetic pole layer and the substrate. This spatial relocation in the vertical dimension allows the coil to achieve greater thickness (reducing resistance) without increasing the horizontal read/write separation distance, as the coil now extends downward toward the substrate rather than upward toward the reproducing head.
Solution Approach 2:
The patent divides the coil structure into distinct segments: the thin-film coil is separated from the reproducing head by the main magnetic pole layer and gap layer. This segmentation allows independent optimization of coil thickness and read/write separation, enabling the coil to be made thicker for lower resistance while maintaining the required separation distance through the magnetic pole structure.
2Power
If the magnetic path length is increased to improve magnetic field generation, then the magnetic field strength improves, but the read/write separation increases beyond constraints
Solution Approach 1:
The patent extends the magnetic path vertically by positioning the thin-film coil closer to the substrate, allowing the magnetic flux to travel through a longer path in the vertical dimension (through the substrate and base insulating layer) rather than horizontally. This increases the magnetic path length for improved field generation without increasing the horizontal read/write separation distance.
3Use of energy by moving object
If the coil-insulating layer is made thicker to accommodate higher current, then the current carrying capacity increases, but the layer protrudes and causes collision with the recording medium
Solution Approach 1:
The patent relocates the thin-film coil and its insulating layer to a position between the main magnetic pole layer and the substrate, away from the reproducing head and recording medium interface. This vertical relocation allows the coil-insulating layer to be made thicker for higher current capacity without protruding toward the recording medium, thereby maintaining head stability and preventing collisions.
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 design effectively decreases the electric resistance of the thin-film coil within the read/write separation constraints, enhances recording density, and improves the stability and writing characteristics of the magnetic head.
Implementation Method 1
a current is caused to flow through the thin-film coil 602 so as to record data onto the recording medium
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
the thin-film coil 602 generates heat when electric current is passed therethrough
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 leading shield part opposing the main magnetic pole layer on the substrate side of the main magnetic pole layer. The thin-film magnetic head has a substrate side coil layer disposed between the main magnetic pole layer and the substrate. In the thin-film magnetic head, a space between a lower end face of the leading shield part and the substrate and a space between an upper end face in the substrate side coil layer and the substrate are formed equal to each other.