JPH0757217A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To suppress a coil resistance value to a low level and to avoid too much increasing in the occupying area of coil patterns. CONSTITUTION:This thin-film magnetic head includes a coil for electromagnetic induction provided with spiral patterns formed by a coil line 20 consisting of a thin-film conductor. The spiral coil patterns are formed to a shape with which the line widths spread gradually from the inner peripheral side toward the outer peripheral side and the space widths between the adjacent lines line up evenly. The more particularly preferable constitution of the coil patterns is as follows: The line widths are even from the center of the spiral patterns to a front direction (-Y direction); the space widths between the adjacent lines line up evenly; in directions exclusive of these directions, the line widths spread gradually from the inner peripheral side toward the outer peripheral side and the space widths between the adjacent lines line up evenly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head, and more particularly to a spiral pattern shape of an electromagnetic induction coil formed on a ceramic substrate.

[0002]

2. Description of the Related Art In a thin film magnetic head for a hard disk, two upper and lower magnetic films (magnetic pole patterns) provided on a ceramic substrate (slider) are separated by a gap film, and a coil film for generating a magnetic field and picking up an induced current is provided therebetween. It is configured to be provided. The coil made of a thin film conductor has a spiral pattern, and when the coil pattern is viewed in all directions from the center, all lines extending from the inner circumference side to the outer circumference side have the same line width and are adjacent to each other. The space width between lines is set to be uniform, and the thickness of all lines is set to be constant.

[0003]

In a magnetic head, it is desirable to keep the total coil resistance value as low as possible. This is because the lower the coil resistance value, the better the S / N and the higher frequency response. For that purpose, it is necessary to widen the coil line width. The number of turns of the coil is determined by design specifications, but it is usually about 30 turns or more, and the larger the number of turns, the better the electromagnetic conversion efficiency. All of these elements act in the direction of increasing the occupied area of the coil pattern. However, in reality, due to the structure of the magnetic head, the area occupied by the spiral coil pattern has a certain limit and cannot be extremely increased.

In the spiral coil pattern, the length of one round becomes longer toward the outer peripheral side. In the conventional coil pattern, the resistance value rapidly increases, and the total coil resistance value becomes a considerably high value. In order to solve this, if the line width is simply widened, the area occupied by the coil pattern becomes large, the length of one round at the outer circumference becomes even longer, and the total coil resistance value does not become so low.
Some conventional thin-film magnetic heads have a line width from the outermost circumference to the 1st to 2nd turns only wider than other parts, but in a magnetic head with a total of 30 turns or more, Hardly contributes to the reduction of the resistance value of.

An object of the present invention is to provide a thin film magnetic head which solves the above technical drawbacks, can keep the total resistance value low, and devises so that the occupied area of the coil pattern does not increase so much. That is.

[0006]

According to the present invention, in a thin film magnetic head having an electromagnetic induction coil in which thin film conductor lines form a spiral pattern, the spiral pattern goes from the inner circumference side to the outer circumference side. A thin film magnetic head having a coil pattern in which the line width gradually expands and the space widths between adjacent lines are evenly arranged.

Here, the line width is uniform from the center of the spiral pattern to the front direction, and the space width between adjacent lines is evenly arranged, and in the other directions, it is from the inner peripheral side to the outer peripheral side. Accordingly, it is preferable to have a coil pattern in which the line width gradually expands and the space widths between adjacent lines are evenly arranged.

[0008]

In the spiral coil pattern, the length of one round becomes longer toward the outer peripheral side. If the cross-sectional area of the lines (thin film conductors) forming the coil pattern is constant, the resistance value increases sharply toward the outer circumference, and the total coil resistance value also increases. In the present invention, the line width is gradually widened toward the outer peripheral side. Therefore, although the length of one round becomes longer, the increase of the resistance value is suppressed and the total resistance value is reduced. Especially, if the line width is constant only in the front direction from the center of the coil pattern, the distance from the center of the coil to the head gap does not become long.

[0009]

EXAMPLE FIG. 2 shows the overall structure of a thin film magnetic head for a hard disk. In the thin-film magnetic head of the present invention, basically, similarly to the conventional case, the upper and lower two layers of magnetic films (magnetic pole patterns) 12 and 14 provided on the ceramic substrate (slider) 10 are separated by the gap film 16, and a magnetic field is generated and generated between them. The configuration is such that a coil line 20 for the induction current pickup is provided.
The coil line 20 is a spiral pattern of thin film conductors (such as copper). The feature of the present invention lies in the shape of the coil line 20.

FIG. 1 shows an embodiment of the coil pattern according to the present invention. In the present invention, the line width is uniform from the center of the spiral coil pattern to the front direction (−Y direction) (this corresponds to the head gap direction, which is the downward direction in FIG. 2), and adjacent lines are adjacent to each other. The space widths between them are evenly arranged, and in the other directions (+ Y direction, + X direction and −X direction orthogonal thereto), the line width gradually expands from the inner peripheral side toward the outer peripheral side and is adjacent. It has a coil pattern in which the spaces between the lines are evenly arranged. In FIG. 1, for convenience, the entire circumference is divided into 20 and drawn by linear approximation, but in reality, patterning is performed with a smooth curve.

Next, Table 1 shows the results of calculation of the total coil resistance value of the coil pattern in which the entire circumference is divided into 20 as shown in FIG. 1 and comparison with the prior art. The conventional example is
All directions from the center of the coil pattern (± X direction and ±
(Y direction), when all the line widths from the innermost peripheral side to the outermost peripheral side are equal, the space width between adjacent lines is also uniform, and the thickness of all lines is set to be constant. is there. The line width in the front direction (-Y direction) is the same in each example, and the other directions are different. Conventional Example 1 is a design example in which the size is made as small as possible (the area occupied by the coil pattern is minimized). The product of the present invention gradually widens the line width from the inner peripheral side to the outer peripheral side in all directions except the -Y direction. Therefore, the occupied area of the coil pattern is slightly larger than that of the conventional example 1, especially on the back side. Conventional Example 2 is an example in which the line width is selected to be slightly larger in each direction other than the -Y direction so that the area occupied by the coil pattern becomes the same as that of the product of the present invention. However, the line width is the same in each direction. The result of Table 1 is that the entire circumference is divided into 20 as described above, the average length and the line width of each coil element are obtained, the line thickness is assumed to be constant, and the specific resistance is multiplied to obtain the resistance of each element. It is the result of calculating the value and adding it for all elements.

[0012]

[Table 1]

From the above, according to the conventional method, the conventional example 2 is used.
Even if the line width is simply expanded as much as possible within the allowable coil pattern occupation area as shown in the above, if the line width is made uniform from the inner circumference side to the outer circumference side in each direction, the total coil resistance It can be seen that it is insufficient to reduce the value.

In the above embodiment, the line width is constant from the center of the coil pattern to the front side. This shape is preferable in that the distance on the front side can be shortened, but in some cases, the line width including the front side may gradually widen from the inner peripheral side toward the outer peripheral side.

[0015]

As described above, the present invention employs a pattern in which the line width gradually increases from the inner circumference side to the outer circumference side, so that the resistance value increases due to the length of one circumference becoming longer toward the outer circumference. Can be suppressed and the total coil resistance value can be reduced. As a result, S
/ N is good, high-frequency response is also improved, and a thin film magnetic head with excellent head characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a coil pattern according to the present invention.

FIG. 2 is a schematic diagram showing the structure of a thin film magnetic head.

[Explanation of symbols]

 10 Ceramics Substrate 12, 14 Magnetic Layer 16 Gap Film 20 Coil Line

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kenji Utsumi 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd.

Claims (2)

[Claims] 1. In a thin film magnetic head comprising an electromagnetic induction coil in which thin film conductor lines form a spiral pattern, the line width gradually expands from the inner circumference side to the outer circumference side of the spiral pattern and is adjacent. A thin-film magnetic head having a coil pattern in which the space widths between adjacent lines are evenly arranged. 2. A thin-film magnetic head comprising an electromagnetic induction coil in which thin-film conductor lines form a spiral pattern, wherein the line width is uniform from the center of the spiral pattern toward the front and adjacent lines are adjacent to each other. In the other direction, the space width is evenly arranged, and in the other directions, the line width gradually expands from the inner peripheral side to the outer peripheral side, and the space widths between adjacent lines are evenly arranged. A thin film magnetic head characterized in that