JPH01223612A - Coil shape for thin film magnetic head - Google Patents

Abstract

PURPOSE:To offer a thin film coil shape for realizing a conversion to a low resistance by using a thin film process technique by forming the coil width of a coil which has been wound round like a plane so as to become gradually larger as it is wound round from the inside periphery to the outside periphery. CONSTITUTION:As for a coil 4' which has been wound round like a plane plural times, although an inter-coil space 10 is constant, coil width 11 of the outside periphery is made large in advance so that the coil width 11 becomes gradually larger as it goes to the outside from the inside periphery. In such a way, a coil resistance is lowered, and a drop rate of the coil resistance is different in accordance with the inter-coil space 10, the external form and the number of turns, but in case of an optimized shape, an effect of a drop of about 10-20% has been obtained. The conversion to a low resistance of the coil can be realized by optimizing the coil shape and using a conventional thin film process technique as it is, therefore, the S/N of a recording and reproducing system can be improved by a drop of a head noise.

Description

[Detailed Description of the Invention] [Summary] Regarding the coil shape of a thin-film magnetic head, the aim is to provide a thin-film coil shape that achieves low resistance using conventional process technology. The coil shape of the thin film magnetic head has a coil having a coil shape, and the width of the coil is gradually increased as the coil is wound from the inner circumference to the outer circumference.

[Industrial application field]

The present invention relates to a coil shape for a thin film magnetic head.

Thin film magnetic heads are used in magnetic recording devices, and have emerged as having excellent high frequency characteristics and being suitable for narrowing tracks, and are gradually establishing their position with the trend toward higher density recording. However, since the coil is formed of a thin film, head noise due to resistance is large, and there is a demand for lower resistance of the coil.

[Conventional technology]

A conventional thin-film magnetic head is shown in Figure 3 (a) and (b).
(a) is a plan view, and (b) is a sectional view taken along the line A-A' in (a).

In FIG. 3, the thin film magnetic head is provided on a substrate 1 made of ceramic or the like, and a lower magnetic layer 3, a coil 4 made of four layers, and a protective film 2 for protecting the upper and lower parts of the element.
It has a structure in which an upper magnetic N5 and an insulating layer 6 are laminated, and a gap 7 is provided at the tip for reading/writing information on the recording medium.

8.9 is a terminal connected to the coil 4.

The shape of the coil 4 has conventionally been an elliptical shape wound multiple times in a plane as shown in FIG.
The space 10 between the coils is constant in the B' and c-c' directions, and the coils are formed with the same width. 12.
13 is a coil end connected to a terminal.

[Problem to be solved by the invention]

The conventional coil 4 shown in FIG. 4 is formed of a thin film,
(Explanation in Figure 3) Its thickness t is 2 to 3 μm, and its width d is 10 μm.
Unlike conventional bulkheads, which are coiled with wire rods with a wire diameter of several tens of micrometers, the resistance value is high because the cross-sectional area is small. Therefore, the thermal noise of the head due to the resistance is large and accounts for a large proportion of the total noise of the recording/reproducing system, making it a challenge to reduce the resistance of the coil.

Therefore, the present invention aims to provide a thin film coil shape that achieves low resistance using conventional thin film process technology.

[Means to solve the problem]

The problem is that, as shown in FIG. 1, the thin film 6-layer head has a coil 4' wound multiple times in a plane, and the coil width 11 of the coil 4' is changed from the inner circumference to the outer circumference. This problem is solved by the coil shape of the present invention, which is formed to gradually become larger as it is wound.

[Effect]

That is, the conventional coil is formed with the same coil width 11 and the same inter-coil space 10 from the innermost circumference to the outermost circumference, and the distance of one round is increased at the outermost circumference compared to the innermost circumference.
Since the resistance was increased, in the present invention, the outer circumferential coil width 11 is made larger than the inner circumferential coil width 11 to reduce the resistance. By optimizing the shape of the coil, an effect of reducing the coil resistance by about 10 to 20% was obtained.

〔Example〕

Generally speaking, methods for lowering the resistance of a coil include (11 increasing the coil thickness, (2) decreasing the space between the coils, and (3) increasing the outermost shape of the coil, but (11 and (2)
(3) requires improvement in process technology, and (3) has the disadvantage of decreasing head efficiency due to an increase in the size of the magnetic circuit (the magnetic path length becomes longer and the magnetic resistance increases). Therefore, in the embodiment of the present invention, by optimizing the coil shape and using the conventional process technology as is, lower resistance was achieved.

The conventional coil 4 shown in FIG. 4 has the same coil width 11 from the innermost circumference to the outermost circumference, and the space between the coils 10.
;Since it was formed by winding, the distance of one round is greater on the outermost circumference than on the innermost circumference. Therefore, in the present invention, the outer coil width 11 is made larger than the inner coil width 11 to reduce the overall resistance.

FIG. 1 shows an embodiment of the present invention, and the outermost and innermost coil shapes are the same as those of the conventional example shown in FIG. 4. A-A' as shown
, B-B', and c-c' directions, the space 10 between the coils was constant, and the coil width 11 was gradually increased toward the outside.

As a result, the relationship shown in Figure 2 was obtained.

FIG. 2 is a graph showing changes in coil resistance, with the vertical axis representing the coil resistance and the horizontal axis representing the width of the outermost coil when the innermost coil width is 1. The figure shows an 8-turn coil, and the ratio of the outermost coil width to the innermost coil width shows the minimum coil resistance at 3, and increases thereafter. This is thought to be because the inner circumferential coil width becomes narrower and the resistance becomes larger.

As shown in the graph in Figure 2, in this example, when the ratio of the outermost coil width to the innermost coil width is about 3, the coil resistance becomes the minimum, which is about 1% compared to the conventional coil with the same pitch.
0% coil resistance has become smaller. (Conventionally 6.59Ω was 5Ω
．． The rate of decrease in coil resistance (graph in Figure 2) when the shape is optimized according to the present invention varies depending on the space 10 between the coils, the outer shape, and the number of turns, but by changing the conditions, it can be reduced to approximately An effect of 10% to 20% reduction was obtained.

〔Effect of the invention〕

As explained above, according to the present invention, by optimizing the coil shape without changing the thin film process technology, etc.
It is possible to reduce the coil resistance value.

This reduces head noise and improves the recording/reproducing system's S/
N can be improved, and high performance thin film magnetic heads can be realized.

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining one embodiment of the present invention, Fig. 2 is a diagram showing changes in coil resistance of the present invention, and Fig. 3 (a) (b).
4 is a diagram illustrating a conventional thin film magnetic head, and FIG. 4 is a diagram illustrating a conventional coil shape. In the figure, 4' is a coil, 10 is a space between coils, 11 is a coil width, and 12.13 is a coil end. Agent Patent Attorney Sada Igeta - Fig. 4/2345678 Mr. Kofuruj's boyfriend of PuJ494 > fiLT Fig.] 5
2 Figure 9.

Claims (1)

[Claims] A coil shape of a thin film magnetic head having a coil (4') wound a plurality of times in a plane, the coil (4')
A coil shape of a thin film magnetic head characterized in that the coil width (11) is gradually increased as it is wound from the inner circumference to the outer circumference.