JPS6151609A - Manufacture of magnetic head - Google Patents

Abstract

PURPOSE:To manufacture a magnetic head having excellent touch with a tape and stable output and long life by forming a notch to a base near the head gap in the direction of gap depth to reduce partially the tickness of a chip. CONSTITUTION:An amorphous alloy 11 is formed by sputtering on a photosensitive glass substrate 10, a laser beam is irradiated on the substrator 10 near a gap 12 of a magnetic head in the direction of gap depth to form a notch A. In this case, the nearest distance to the amorphous alloy 11 is processed in 10mum at the apex of the notched triangle form. Similarly, a head processed with notches of shapes B, C is formed. The head output having a wider notch area than that of the shape A is made stable and the head with the shape B has excellent wear resistance. Thus, the head provided with the notches near the gap to decrease the head chip width, with long service life and stable output and excellent touch with a tape is manufactured in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic head for a magnetic recording/reproducing device.

Conventional Structures and Problems Generally, alloy materials such as permalloy and sendust, ferrite, and the like are used as head core materials for magnetic heads. When considering these materials especially for heads for video tape recorders (hereinafter referred to as VTR), ferrite is currently the most popular material because it has the best wear resistance.

By the way, in the case of a VTR head, the track width is 30 mm.
Since the track width is extremely small, on the order of μm, making a chip with the same width as the track width may cause problems in machining, strength of the chip itself, or handling, so in reality, the chip thickness is increased and the track width is specified only in the vicinity of the gap. A so-called notch process has been applied to reduce the trunk width.

This state is shown in FIG. In FIG. 1a, 1 is a magnetic material made of ferrite, 2 is a winding window, 3 is a head gap, and 4 is a notch portion. That is, before forming the gap, a notch is formed in advance, and the notch portion 4 is filled with glass or the like and then the gap is formed to obtain a gap-formed rod.

This gap forming rod is cut along the plane indicated by X-X,
A head chip as shown in Figure 1 is obtained. As a result, a track width t smaller than the chip thickness is obtained.

On the other hand, various recording media are used,
Recently, high-density recording media with high coercive force have appeared. When using this, the material must have a high saturation magnetic flux density so that the magnetic helad core does not undergo magnetic saturation. For this reason, ferrite is inappropriate as the core material for magnetic heads that are compatible with the above-mentioned high-density recording media, and alloy materials are suitable.From this perspective, amorphous materials have been attracting attention in recent years. There is a quality alloy. Amorphous alloy materials have different manufacturing characteristics,
Since it is characterized by making a rather thin material of about 20 to 5 Q .mu.m, various companies have announced magnetic heads whose material itself is equal to the track width. Generally, it has a laminated structure in which the head core is made of the above amorphous alloy and is sandwiched between substrates having good wear resistance.

An example of the manufacturing method will be explained with reference to FIG.

FIG. 2a shows a Guyang-formed rod with a gap formed therein, where 5 is an amorphous alloy, 6 is a non-magnetic substrate material, 7 is a magnetic gap, 8 is a winding window, and 9 is an adhesive glass. Y, depending on the desired chip width for such a gap forming rod.
-Yl, Y2-Y2 to obtain a bar as shown in Figure 2. It is further cut as indicated by Z--Z in Figure 2, and each chip as indicated by C is cut out to complete the magnetic head.

By actually running the tape with the conventional head described above,
When evaluating the characteristics of the head, first of all, the ferrite head has very good wear resistance, but since the glass in the notch has inferior wear resistance compared to ferrite, only the ferrite core has a protruding shape on the order of angstroms. This allows for good contact between the front of the head and the tape, resulting in stable output.

On the other hand, amorphous alloys have inferior wear resistance compared to ferrite, so as mentioned above, they are sandwiched between glass or non-magnetic ferrite substrates with good wear resistance, creating a so-called sand inch structure. A magnetic head with wear resistance comparable to that of ferrite has been obtained.

However, in magnetic heads with such a laminated structure, the substrate material used as the head core is an amorphous alloy, which also has good wear resistance, so if the magnetic tape is run for a long time, the tape slider that comes into contact with the magnetic tape will wear out. On the moving surface, the head core also sinks into the substrate, causing uneven wear. When this uneven wear occurs, the contact between the magnetic tape and the head core becomes poor, and the resulting spacing loss significantly reduces the output, especially in the MHz order. If the wear exceeds 500 Å, it becomes difficult to record and play back video signals, for example.

From this point of view, it is easy to think that uneven wear would be reduced if the amorphous alloy head had the same structure as the ferrite head, that is, a notch type head, but as mentioned above, the amorphous It is impossible to notch a quality alloy head in advance.

In that case, it is sufficient to process a notch in the substrate material near the gap after forming the head chip, but in the case of a VTR head, for example, the total tip thickness is 130 μm.

The gap is 0.3μm, the chip width is about 2aJI,
Creating a notch while maintaining the gap is impossible with current processing technology.

A slightly possible method is to taper only the head tip 7 by lapping as shown in Fig. 3, but with this method, the contact between the head and the tape is good at the beginning of the tape run, but As head wear progresses, the core width that comes into contact with the tape near the head gap increases, causing the aforementioned uneven wear and resulting in a decrease in head output.

On the other hand, a part of the amorphous alloy is irradiated with the beam from a laser beam or an electron beam processing machine, and is locally heated to crystallize it and make it non-magnetic, thereby trimming the head track width. Although it has not been put into practical use, it has been proposed as an idea to do this or create a pseudo gap. All of these are heated → crystallized →
It was devised using a process called demagnetization. It was common knowledge that irradiating the vicinity of the amorphous alloy with the beam in this way was to make it non-magnetic.

OBJECTS OF THE INVENTION The present invention provides a practical magnetic head that has good contact between the head and tape, stable head output, and has a long life.

In a magnetic head with a laminated structure in which a magnetic core is sandwiched between highly wear-resistant substrates, the portion of the substrate near the gap is also processed in the direction of the gap depth using a laser beam or an electron beam to provide a notch. Another feature is that the chip width near the gap is reduced.

Words using laser beams or electron beams,
Fine notches can be easily processed without damaging the magnetic alloy layer.

Description of examples Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 4 is a drawing of the tape sliding part of the completed amorphous head, which has dimensions of 2×0.14 all, and 10 is a substrate made of commercially available photosensitive glass. 11 is an amorphous alloy, which is a so-called metal of Co-Nb-Zr system.
A metal material was formed on the substrate 10 by sputtering. 12 indicates a gap.

A notch was formed in the shape shown in FIG. 4 (a) by processing the substrate 10 in the vicinity of the gigantic head 12 of the magnetic head constructed in this manner by irradiating the YAG laser beam in the direction of the gap depth. . Examining the apex of the triangle of the notch shape, that is, the closest distance to the amorphous alloy 11, it was found that the distance up to 10 μm could be processed without any loss in the characteristics of the magnetic head. The processing described below was also performed with the closest distance being 10 μm. In the same way as above, heads with mouth and no-1 shaped notches were also created.

Note that the diameter of the irradiated laser beam at this time was approximately 10 μm.
Machining was performed almost vertically. Considering practicality, the machining depth should be about the gap depth.
-The crystallization temperature of the Nb-Zr amorphous alloy is 580″C
Met.

Changes in head output and amount of head wear with respect to the running time of various tapes processed in this way were measured in the fifth and
It is shown in Figure 6. In the diagram (a), (b), ? -i corresponds to the notch shapes (A), (B), and (C) in FIG. 4, and 9) in the figure shows a conventional head without a notch for reference. As is clear from the figure, regarding the head output (A).

(B) and (C) It was found that the wider the area of the notch, the more stable the head output could be obtained.

Regarding (b) and (c), the initial values themselves are improved compared to (without notches), but this is due to the fact that when the front surface of the head is polished and finished, there is already a gap between the amorphous alloy and the substrate glass. This means that uneven wear has occurred.

As for head wear, as is clear from Figure 6, (
Shapes A) and (B) are the same as conventional heads, so there is no problem at all, and shape (C) has slightly more head wear than the conventional head. From the above results, the shape (b) has a head output,
It can be seen that good results are obtained with respect to wear.

The shape of the notch in this embodiment has been described above as a triangular one-arc shape, but there is no problem with rectangular, square, semicircular trapezoid, etc., but tape residue may adhere to the notch. Taking this into consideration, the shapes (0) and (c) described in the embodiment are desirable.

Further, the amorphous alloy may be a so-called metal-metalloid amorphous alloy represented by the Fe-Co-3i-B system, and the manufacturing method may not be a sparter, but an ultra-quenched ribbon using a normal roll method. Considering the influence of heat caused by the irradiation of the irradiation beam, it is preferable to use a material with a high crystallization temperature.

' The substrate material may be any material that can be processed by laser or electron beam, such as non-magnetic ferrite, S s 0
Any glass material containing 2 as a main component can be used.

Although this embodiment describes a YAG laser, it is also possible to use a carbon e gas laser, a ruby laser, a glass laser, etc., but there are difficulties in narrowing down the beam.
AG laser is the best.

Processing by electron beam irradiation is also possible, but it is inferior in terms of workability because the process must be performed in a vacuum.

Effects of the Invention The present invention provides an amorphous alloy magnetic head having a laminated structure.
The substrate near the head gap is partially cut out using laser beams or electron beams, etc., and the head step width is reduced only near the gap, resulting in good contact between the head and tape and stable head output. A practical magnetic head with a long life can be provided.

A perspective view illustrating the manufacturing process of the head, FIG. 3a,
b and C show the front end of a conventional amorphous alloy head, respectively, a front view, a top view, and a side view; FIGS.
FIG. 5 is a plan view and a front view of an amorphous alloy head according to an embodiment of the present invention. FIG.
The figure is also a graph showing head wear versus tape running time.

1o...Substrate, 11...Amorphous alloy,
12...gap, (a), ←), l/tsu...
...notch part.

Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (3)

[Claims] (1) A magnetic head chip has a laminated structure in which a head core made of a magnetic material is sandwiched between substrates having good wear resistance in the vicinity of the tape sliding surface of the head chip that contacts the magnetic tape, and The substrate near the magnetic head gap, including the sliding surface, is processed in the gap depth direction using a laser beam, an electron beam, etc. to form a notch, thereby partially reducing the thickness of the head chip. A method of manufacturing a magnetic head. (2) The method of manufacturing a magnetic head according to claim 1, wherein the process of partially reducing the thickness of the head chip is performed after the head gap is formed. (3) The method of manufacturing a magnetic head according to claim 1, wherein the magnetic material constituting the head core is an amorphous soft magnetic alloy.