JPH04195810A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain good contact with a tape with time by processing a head front part to satisfy such a relation between a taper angle theta1 from a tape sliding surface to at least a gap depth zero point and a taper angle theta2 in the rear of this as theta1 < theta2. CONSTITUTION:At the time of processing the head along a sliding width regulating areas 91 and 92, the area 91 has a width that is not capable of cutting upper and lower magnetic cores, extending from the tape sliding surface to at least the gap depth zero point Z, and the tape angle theta1 is desirable to be small to achieve good tape slidability with time. Then, the area 92 is of a shape that is not in contact with the outermost circumferential part of a coil, and the taper angle theta2 is larger then theta1, and moreover, the shape is not capable of abutting its point B against the curved tape 10 at the time of sliding over the tape. Thus, because the coil forming area is not diminished but the sliding width can be narrowed, good contact with the tape can be obtained without increasing coil resistance.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a thin film magnetic head used in magnetic recording and reproducing devices such as VTRs, which improves tape contact and further reduces the resistance of the thin film coil. The present invention relates to a thin film magnetic head.

[Conventional technology]

Conventionally, as a thin film magnetic head, for example, Japanese Patent Application Laid-Open No. 1182
As described in Publication No. 907, after forming a lower magnetic core, a signal coil, and a coil insulating material on a nonmagnetic substrate, an upper magnetic core is formed to form a magnetic circuit with the lower magnetic core, and a protective film is further formed. An example of this method is to form a film and then cut it into individual head elements.

FIG. 7 is a plan view of a head formed by this conventional technique.

1 is a non-magnetic substrate, 6 is a signal coil, 7 is an upper magnetic core,
9 is a processing position for defining the sliding width, W is the head sliding width, and Tw is the track width. In order to improve the slidability between the tape and the head, the head sliding width W is preferably narrower. Conventionally, in order to avoid cutting the signal coil 6, the structure was such that it became narrower from the outer periphery of the coil toward the sliding surface.

[Problem to be solved by the invention]

However, in the conventional sliding width processing method described above, in order to prevent tape contact from worsening due to wear of the head after tape sliding and widening of the sliding width, the taper angle at the processing position t9 is set at a maximum of 60°. For this reason, the 8th
As shown in the figure, when the sliding width W was further narrowed, the area where the coil was formed had to be made smaller to prevent the coil from being cut, which caused the problem of increased coil resistance6. The wider the sliding width due to surface wear is, the smaller the taper angle is, the smaller the taper angle, but in the past, the minimum limit was 30°, considering that the coil formation area became smaller and the coil resistance increased. It has become difficult to obtain good tape contact.

The purpose of the present invention is to secure a coil formation area and not increase resistance even if the sliding width W is narrowed. Furthermore, by creating a structure in which changes in the head sliding width due to tape sliding are small, it is possible to The purpose is to obtain good tape contact.

[Means to solve the problem]

In order to achieve the second objective, the head front section is designed such that the taper angle θ1 from the tape sliding surface to at least the zero gap depth and the size of the rear taper angle 02 are in the relationship Ol<θ2. Processing is performed on the

Further, in order to widen the coil forming area, the processing behind the zero gap depth position is performed in multiple steps.

Further, processing is performed so that the taper angle 01 from the sliding surface of the head front to the zero gap depth becomes Oo.

[Effect]

Since the tape sliding part of the head front part and the tape sliding part behind it are processed separately, even if the sliding width is narrowed, the coil forming area remains unchanged and the coil resistance does not increase. Similarly, since the sliding width can be narrowed regardless of the coil resistance, tape contact becomes better. Furthermore, since the structure is such that the change in head sliding width due to tape sliding is small, even if the head is worn out after tape sliding, good tape contact can be obtained as in the initial stage.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a thin film magnetic head according to the present invention, and FIG.
The figure is a sectional view taken along the dividing line AA' in FIG.
is a non-magnetic substrate, and 2 is a lower magnetic core.

3 is a lower magnetic core embedding material, 4 is a gap, 5 is a signal coil insulating material, 6 is a signal coil, 7 is an upper magnetic core, 8 is a protective film, 91.92 is a sliding width regulation area.

W is the head sliding width, and Tw is the track width.

1 and 2, the magnetic cores include a lower magnetic core 2 embedded in a groove formed in a non-magnetic substrate 1, and an upper magnetic core formed via a signal coil insulating layer 5 and a signal coil 6. Consists of 7. Further, the upper and lower magnetic cores 2 and 7 are connected via a gap 4 formed in a rear core connecting portion through hole and a front portion through hole opened in the insulating layer 5. Note that the magnetic core material is formed of a Co-based amorphous alloy by sputtering or the like.

The signal coil 6 has a two-layer spiral structure, with the first layer 4
Turn, 2nd layer 3 turns. Note that the coil is formed by evaporating Cu using Cr as a bonding layer.

An insulating material such as forsterite is formed on the upper layer of the upper magnetic core 7 by sputtering or vapor deposition.

After the above steps, each head is cut by machining. Further, processing is performed along the sliding width defining regions 91 and 92. At this time, the region 91 has a width that does not cut the upper and lower magnetic cores, and the tape sliding surface extends to at least the zero gap depth, and the taper angle θ1 is set to be as small as possible in order to improve the tape sliding properties over time. is preferred. Further, the region 92 has a shape that does not touch the outermost circumference of the coil, the taper angle o2 is larger than θ1, and furthermore, when the tape moves as shown in FIG. 3, the point B does not hit the curved tape 10. Any shape is fine.

According to this embodiment, since the sliding width can be narrowed without reducing the coil forming area, good tape contact can be obtained without increasing the coil resistance.

FIG. 4 is a plan view of a thin film magnetic head showing a second embodiment of the present invention, and the same parts as in FIG. 1 are designated by the same numbers. In FIG. 4, the steps up to the area 91 of the head sliding portion are the same as those in the first embodiment, and will therefore be omitted. The area 92 is
The area from point C1 to point C3 behind the region 91 processed at taper angle θ1 is shown, and the processing is performed in two steps: from point C1 to point C2 and from point C2 to point C3. At this point C
2 has a structure in which a corner protrudes from the sliding surface side, and points C2 and C3 need only have a shape that does not come into contact with the tape, as in the first embodiment. In addition, the shape of the area 92 (points C1, C
2 and C3) may be polygonal or arcuate.

According to this embodiment, in addition to the same effects as the first embodiment,
Furthermore, coil resistance can be reduced.

FIG. 5 is a plan view of a thin film magnetic head showing a third embodiment of the present invention, and the same parts as in FIG. 1 are designated by the same numbers. In this embodiment, the taper angle θ1 is set to Oo in the first embodiment. In FIG. 5, the steps up to the formation of the protective film are the same as those in the first embodiment, and are therefore omitted.

After cutting each head by machining, the sliding width specified area 9
1. ．． Processing is performed along 92. At this time, the region 91 is processed in a direction parallel to the gap depth direction. Further, the taper angle θ2 of the region 92 may be any shape as long as it does not come into contact with the tape when sliding. However, considering the coil resistance, it is better to make it as large as possible.

According to this embodiment, the sliding width can be narrowed without reducing the coil forming area, and the head sliding width does not change even after tape sliding, so that the sliding width can be reduced over time without increasing the coil resistance. Stable tape contact can be obtained.

FIG. 6 is a plan view of a thin film magnetic head showing a fourth embodiment of the present invention, and the same parts as in FIG. 1 are designated by the same numbers. In this embodiment, in the second embodiment, the taper angle θ
1 is taken as 0°.

Step 4 up to area 91 of the head sliding part in FIG.
is the same as in the third embodiment, and will therefore be omitted. The area 92 is processed in two steps as in the second embodiment, and the point C
The structure is such that a corner 2 is formed to protrude toward the sliding surface. At this time, the positions of point C2 and point C3 can be expanded within a range that does not contact the tape. In addition, the shape of area 92 (point C1
, C2, and C3) may be polygonal or arcuate.

According to this embodiment, in addition to the same effects as the third embodiment,
Furthermore, coil resistance can be reduced.

〔Effect of the invention〕

According to the present invention, since the coil forming area does not depend on the tape sliding width, the sliding width can be narrowed while maintaining a predetermined coil resistance, and good tape contact can be obtained. Furthermore, since the coil formation area can be expanded, the coil resistance can be reduced. Furthermore, since the change in the sliding width of the head due to tape sliding can be made small, even if the head is worn out after tape sliding, good sliding performance can be obtained as in the initial stage.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the thin film magnetic head according to the present invention; FIG. 7 is a plan view showing another embodiment of the thin film magnetic head according to the present invention;
FIG. 8 is a plan view of a conventional thin film magnetic head. ■--Nonmagnetic substrate 2... Lower magnetic core 6...
- Signal coil 7... Upper magnetic core 91, . 92
...Sliding width specified area

Claims (1)

[Claims] 1. Magnetic cores (2), (7), gap (4), signal coil (6), insulating layers (3), (5), and protective film (8) on substrate (1). In a thin film magnetic head that is formed into a predetermined shape and cut into each head, the shape of the front side of the head, which is narrower than the width of the rear side of the head when viewed from the front in the film deposition direction, is the zero gap depth. It consists of two areas: the area up to (91) and the area behind it (92), and the area (91)
The taper angle (θ1) of the area (92) and the taper angle (θ1) of the area (92)
2) A thin film magnetic head characterized in that there is a relationship (θ1)<(θ2). 2. The thin film magnetic head according to claim 1, wherein the shape of the region (92) is polygonal or arcuate, which is convex toward the sliding surface and has at least one inflection point. Thin film magnetic head. 3. The thin film magnetic head according to claim 1 or 2, wherein the taper angle (θ1) of the region (91) is 0°.