JPS62128011A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To extend the area of heat radiation and to obtain a small-sized exciting coil operated with a large current by providing a metallic piece forming a part of the exciting coil or a metallic piece adjacent to the exciting coil. CONSTITUTION:Since an exciting coil projecting part 9 is provided and heat is radiated even from under the exciting coil projecting part 9, the rise of temperature can be reduced. In this case, the electric characteristic is scarcely degraded by this exciting coil projecting part 9 because the inside coil shape is equal to conventional that though the exciting coil shape is larger. The exciting coil projecting part 9 is notched radially to reduce furthermore the degradation in electric characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a thin film magnetic head that reduces temperature rise due to excitation current and enables large current operation.

<Prior art and its problems> FIG. 4 shows an example of the configuration of a conventional thin film magnetic head. 1 is an excitation coil, 2 is a lower magnetic pole, 3 is an upper magnetic pole, 4 is an insulating layer, 5
6 represents a base protective layer, 6 represents an upper protective layer, 7 represents a substrate, and 8 represents a land.

The function of this head is to cause an excitation current to flow through the excitation coil 1 to generate a recording magnetic field in the gap, and to record a signal on a magnetic recording medium placed near the gap. In this case, it is generally known that increasing the coercive force of the medium is effective in increasing the amount of information written per unit length on the medium (recording density). In order to improve this, there is a tendency to use media with a large coercive force. In order to increase the magnetic field generated by the magnetic head as the coercive force increases, it is necessary to flow a higher excitation current.

Furthermore, in order to use thin-film magnetic heads at higher frequencies, there is a tendency to reduce the number of windings and reduce the inductance, but a reduction in the number of windings results in an increase in the excitation current required for recording.

This increase in excitation current causes a rise in temperature, and as shown in FIG. However, since the insulating layer 4 is generally made of a material such as resist, which has a lower thermal conductivity than metal, or a material such as SiO2, a The flow of the generated Joule heat to the substrate 7 is blocked, and the excitation coil 1
The temperature of the insulating layer 4 is increased, and this temperature increases approximately in proportion to the excitation current. In a thin film head constructed by laminating different materials, there is a natural limit to the temperature at which it can be used, and the resist material undergoes thermal deformation at a temperature of several hundred degrees, reducing the reliability of the thin film head. As a result, the current ・＼nod has the disadvantage that the excitation current is limited.

In order to improve this drawback, there is a method of increasing the length of the excitation coil wire 11 to reduce the generated Joule heat, but this increases the size of the excitation coil and loses the characteristics of the thin-film magnetic head that can be made smaller. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film magnetic head that enables large current operation with a small excitation coil by efficiently discharging Joule heat generated in the excitation coil and heat from the substrate.

Means for solving the problems and their effects〉The present invention has the following features:
The most important feature is that a convex portion is formed radially on the outside of the excitation coil, or a metal piece is formed that is thermally connected to the excitation coil. This makes it possible to equivalently increase the thermally opposing area between the excitation coil and the substrate, making it possible to efficiently dissipate the Joule heat generated in the excitation coil to the substrate. can flow a large current.

Embodiment Example 1 FIG. 1 shows a head showing a first embodiment of the present invention,
1 is an excitation coil, 2 is a lower magnetic pole, 3 is an upper magnetic pole, 4 is an insulating layer, 5 is an underlying protective layer, 6 is an upper protective layer, 7 is a substrate, 8 is a land, and 9 is a convex portion of an exciting coil. The excitation coil convex portion 9 is connected to the excitation coil 1 and extends in a plate shape around the excitation coil 1, and has radial grooves formed therein, so that it is configured as a plate-like convex portion.

By providing the excitation coil convex part 9, heat is exhausted only from the lower part of the excitation coil 1 in the conventional thin film magnetic head, but in this thin film magnetic head, heat is also exhausted from the lower part of the excitation coil and coil convex part 9. aB, it is possible to reduce the temperature rise. In this case, although the shape of the excitation coil becomes larger, the inner coil shape is the same as the conventional one, so there is almost no deterioration in electrical characteristics due to the provision of the excitation coil convex portion 9.

Moreover, in this embodiment, by providing radial sparks in the excitation coil convex portion, deterioration in electrical characteristics can be further reduced.

[Example 2] FIG. 2 shows a head showing a second example of the present invention,
1 is an excitation coil, 2 is a lower magnetic pole, 3 is an upper magnetic pole, 4 is an insulating layer, 5 is an underlying protective layer, 6 is an upper protective layer, 7 is a substrate, 8 is a run, and 10 is a metal piece. This metal piece 10 is located below the excitation coil 1 and has a plate-shaped structure extending substantially on the same plane as the lower magnetic pole 2. By providing this metal piece, whereas in conventional thin-film magnetic heads heat is exhausted only from the lower part of the excitation coil 1, in this thin-film magnetic head heat is also exhausted from the lower part of the metal piece. It becomes possible to reduce the increase. In this case, the manufacturing process is slightly complicated, but the excitation coil 1 and the metal piece 10
Although it is thermally connected to the excitation coil 1, it is electrically insulated, and there is no deterioration in the electrical characteristics of the excitation coil 1 at all.

[Embodiment 3] FIG. 3 shows a head showing an embodiment in which the present invention is applied to an excitation coil 1 having a shape other than a spiral, in which 1 is an excitation coil,
2 is a lower magnetic pole, 3 is an upper magnetic pole, 4 is an insulating layer, 5 is a base protective layer, 6 is an upper protective layer, 7 is a substrate, 8 is a land, and 9 is a convex portion of an exciting coil. This excitation coil 1 is a coil formed by connecting wires between the cows 1:8 so that the upper part surrounds the lid 3 three-dimensionally, and has excitation coil convex portions 9 on both sides of the coil. In this way, the present invention can obtain similar effects even when applied to an excitation coil having a shape other than a spiral shape.

<Effects of the Invention> As described above, by forming the metal pieces and the convex portions, the heat dissipation area becomes wider, the heat dissipation efficiency can be increased, and a small excitation coil can be obtained with large current operation.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a first embodiment of the present invention, FIG. 2 is a structural diagram of a second embodiment of the present invention, and FIG. 3 is a structural diagram of a third embodiment of the present invention. FIG. 4 is a perspective view of a conventional thin film magnetic head, and FIG. 5 is an explanatory diagram of heat flow within the head. In the figure, 1 excitation coil, 2 lower magnetic pole, 3-- upper magnetic pole, 4
Insulating layer, 5 Base protective layer, 6. Upper protective layer, 7. Substrate,
8 land, 9 - excitation coil convex portion, 10 metal piece. Patent applicant: Agent of Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] In a thin film magnetic head that is constructed by laminating a magnetic circuit, an insulating layer, an excitation coil, etc. formed of thin films having a predetermined shape and thickness, a metal piece forming a part of the excitation coil or a A thin film magnetic head comprising adjacent metal pieces.