Dynamic information storage or retrieval – Storage or retrieval by simultaneous application of diverse... – Magnetic field and light beam
Reexamination Certificate
2002-02-14
2004-03-09
Davis, David (Department: 2652)
Dynamic information storage or retrieval
Storage or retrieval by simultaneous application of diverse...
Magnetic field and light beam
Reexamination Certificate
active
06704249
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head used for writing data to or reading data from a magneto-optical disk or a magnetic disk. The term “magnetic head” used in this specification refers to any type of data-writing/reading head provided with a magnetic field generating coil. Thus, for example, the “magnetic head” may refer to a magneto-optical head.
2. Description of the Related Art
When an electric current passes through the coil of a magnetic head for generation of a magnetic field, the coil is heated up. As the temperature of a coil increases, the electric resistance of the coil also increases. Thus, to generate an appropriately strong magnetic field with the coil heated up to a higher temperature, the power supply to the coil needs to be increased. However, with a large power supply, the coil may be overheated, thereby damaging the coil itself and/or the surrounding components of the magnetic head. Further, the large power supply may cause “electromigration” in the coil. As a result, the conductive element of the coil may become thinner or even break due to the growth of a void (in the conductive element) resulting from the electromigration.
Since the heat generation in the coil can lead to the damaging of the coil, an appropriate countermeasure should be provided. One solution is suggested in JP-A-8-235556 which discloses a magnetic head as shown in FIG.
14
. This conventional magnetic head includes a slider
91
supported by a suspension
90
in facing relation to a data storage disk D. The slider
91
is provided with a coil
92
for generating a magnetic field. In its bottom surface (facing the disk D), the slider
91
is formed several grooves
93
each of which extends generally in the track direction of the disk D.
With the above arrangements, the slider
91
is caused to float over the disk D in rotation, and the air flowing between the slider
91
and the disk D passes through the grooves
93
. The passing air takes away some heat from the slider
91
.
While the conventional magnetic head is functional in many respects, it still has some drawbacks in terms of prevention of the temperature rise in the coil
92
.
Specifically, the slider
91
is typically made of a synthetic resin, which is not an excellent heat conductor. In addition, the coil
92
is enclosed by a dielectric protection coating made of e.g. silicon oxide which is not an excellent heat conductor, either. Thus, while the exposed surface of the slider
91
is cooled by the high-speed air flow, the temperature of the heated coil may not significantly decrease due to the existence of the materials of low heat conductivity.
Further, though the conventional slider
91
is provided with the grooves
93
for enlarging the heat-dissipating area, each groove
93
has merely a simple, straight configuration whose width is constant over the entire length of the groove. Thus, the passing air may fail to contact with the entire wall surface of the groove
93
, and therefore cannot take away a sufficient amount of heat from the slider
91
.
SUMMARY OF THE INVENTION
The present invention has been proposed under the circumstances described above. It is, therefore, an object of the present invention to provide a magnetic head which is capable of efficiently preventing the temperature rise in the coil.
According to a first aspect of the present invention, there is provided a magnetic head comprising: a dielectric member including an obverse surface facing a data storage disk; a coil that generates a magnetic field and is held in engagement with the dielectric member; and a heat conductor that takes heat generated by the coil and has a heat conductivity higher than a heat conductivity of the dielectric member. The heat conductor includes an irregular surface.
Preferably, the irregular surface may be exposed from the obverse surface of the dielectric member.
According to a second aspect of the present invention, there is provided a magnetic head comprising: a dielectric member including an obverse surface facing a data storage disk; a coil that generates a magnetic field and is held in engagement with the dielectric member; and a heat conductor that is provided in the dielectric member and includes a first portion and a second portion. The first portion is positioned opposite to the disk with respect to the coil, while the second portion is exposed from the obverse surface of the dielectric member. The heat conductor has a heat conductivity higher than the heat conductivity of the dielectric member.
According to a third aspect of the present invention, there is provided a magnetic head comprising: a coil for generating a magnetic field; and a surface that faces a data storage disk and is formed with a plurality of grooves for allowing air to pass when the disk is rotated. Each groove includes an inlet end for entry of the passing air and an outlet end for exit of the passing air. Each groove becomes narrower from the inlet end to the outlet end.
According to a fourth aspect of the present invention, there is provided a magnetic head comprising: a coil for generating a magnetic field; and a surface facing a data storage disk. This surface includes an irregular portion provided with a plurality of projections spaced from each other in a track direction and a tracking direction of the disk.
Other features and advantages of the present invention will become clearer from the detailed description given below with reference to the accompanying drawings.
REFERENCES:
patent: 6584045 (2003-06-01), Ishii et al.
patent: 8-235556 (1996-09-01), None
patent: 9-305903 (1997-11-01), None
patent: 2000-090403 (2000-03-01), None
Machine Translation of JP 2000-090403, Mar. 31, 2003, Kazunori.
Fujimaki Tohru
Kawasaki Goro
Matsumoto Tsuyoshi
Yoshikawa Hiroyasu
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