Thin Film Magnetic Head Thermal Protrusion Control
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Solution Overview
Problem
The increasing recording density in magnetic disks poses challenges for maintaining a precise and stable small magnetic spacing between the thin film magnetic head and the disk surface, as existing technologies struggle with controlling heat generation and temperature variations, leading to potential contact issues and signal abnormalities.
Innovation Solution
A thin film magnetic head configuration with separate heat generation and temperature detection means for both read and write head sections, allowing independent power adjustment to optimize protrusion and maintain a precise magnetic spacing, featuring heaters and resistance sensors positioned to minimize heat interference and maximize control over the air bearing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the magnetic head slider is moved upward to reduce magnetic spacing, then recording density is improved, but the thin film magnetic head comes in contact with protrusions on the magnetic disk surface causing abnormal signals and abrasion
Solution Approach 1:
The patent applies thermal expansion by providing heat generation means on the substrate to expand the substrate thermally, thereby protruding the air bearing surface in the thickness direction to reduce magnetic spacing. This allows the magnetic head to maintain closer proximity to the disk surface for higher recording density without mechanical contact, as the thermal expansion provides a controlled, uniform protrusion that avoids contact with disk protrusions.
Solution Approach 2:
The patent changes the physical state of the substrate from a fixed dimension to a thermally expandable parameter. By controlling the temperature of the substrate through heat generation means, the magnetic spacing can be dynamically adjusted without mechanical movement of the entire head slider, thus maintaining signal stability while achieving higher recording density.
2Productivity
If heat generation means is provided to reduce magnetic spacing, then recording density is improved, but temperature control becomes difficult leading to contact issues
Solution Approach 1:
The patent implements feedback by providing temperature detection means to detect the temperature of the substrate, and using this information to control the heat generation means. This closed-loop control system maintains temperature stability while enabling the substrate to expand thermally for reduced magnetic spacing, thus preventing contact issues.
Solution Approach 2:
The patent replaces mechanical adjustment mechanisms with a thermal field-based system. Instead of mechanically moving the head slider to change magnetic spacing, the system uses thermal expansion of the substrate to achieve the same effect, thereby eliminating mechanical contact issues while maintaining temperature control through detection and feedback.
3Productivity
If the magnetic head is reduced in dimension to match narrower recording tracks, then recording density is improved, but the capability of magnetic write element and signal magnetic field intensity are reduced
Solution Approach 1:
The patent uses thermal expansion to compensate for the reduced dimensions of the magnetic head. By heating the substrate, it expands in the thickness direction, effectively increasing the protrusion of the air bearing surface. This thermal expansion compensates for the reduced magnetic spacing capability, allowing the smaller magnetic head to maintain sufficient signal magnetic field intensity for high-density recording.
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 precise control of magnetic spacing, reducing the likelihood of contact and enhancing recording density by allowing independent optimization of read and write head sections, thus improving signal integrity and stability.
Implementation Method 1
the magnetic conversion element is protruded to the side of the ABS utilizing the thermal expansion of the area in the vicinity of a heating element due to the heat generation thereof
Implementation Method 2
a temperature detection section is provided, and based on information about the detected temperature, the amount of power supply for a heating element is controlled
Data Source
AI summary
This thin film magnetic head has a magnetic read head and a magnetic write head each having respective end surfaces exposed to an ABS. The magnetic read head includes a magnetic reader including an end surface exposed to the ABS, first heat generator disposed on an opposite side of the magnetic reader from the ABS, and first temperature detector disposed closer to the ABS than the first heat generator is. The magnetic write head includes a magnetic pole having an end surface exposed to the ABS, second heat generator, and second temperature detector disposed closer to the ABS than the second heat generator is. The first heat generator and the first temperature detector adjust the protrusion of the magnetic read head, and the second heat generator and the second temperature detector adjust the protrusion of the magnetic write head.