JPS6248285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic head suitable for application to a video tape recorder.

In a general video tape recorder, as shown in Fig. 1, a pair of magnetic heads 2 and 3 installed at symmetrical positions on a rotary disk 1 are operated alternately to create a recording trail in a direction diagonal to the longitudinal direction of the magnetic tape. or, conversely, to extract signals from the recorded traces. In order to reduce the amount of magnetic tape consumed for magnetic recording and reproduction, or in other words, to lengthen the recording and reproduction operation, the track width and pitch of the recording trace during recording and reproduction should be made as small as possible, especially the track pitch. There is a tendency to make it smaller than the track width. This overlapping recording method is made possible by utilizing the azimuth loss of the magnetic head, but in order to maintain high quality recording and reproducing characteristics in this method, 1.
Uniformity of the individual characteristics of the magnetic heads of the set as well as accuracy of the azimuth angle must be ensured.
That is, each of the magnetic heads 2 and 3 must be arranged so that the shape of the tape contacting surface when viewed from the direction of arrows A and B in FIG. 1A is as shown in FIG. 1B and C, respectively. Here, the angle θ is the azimuth angle.

On the other hand, various materials have been proposed for the core material that makes up the magnetic head, taking into consideration magnetic properties, lifespan, cost, etc., but overall, the material that makes up the magnetic head core and the tape contacting part of the magnetic head. The first layer is made of a magnetic material suitable for
There is an opinion that it is better to use a combination of a magnetic material and a second magnetic material made of a magnetic material suitable for forming the magnetic circuit section of the magnetic head (for example, polycrystalline ferrite with low core loss).

In order to manufacture magnetic heads with different azimuth angles using this composite core, as shown in FIG. 1 B and C, two blocks 4 obtained by the process shown in FIG. It was said that each block had to be sliced to have a different azimuth angle (θ, -θ) and each slice had to be used as a set of magnetic head cores. It was difficult to obtain something that was symmetrical with respect to a plane perpendicular to the abutment surface. In Fig. 2, 5 and 6 are ingots of single crystal and polycrystalline ferrite, 7 is a block obtained by dividing and joining these ingots,
Reference numerals 8 and 9 are block halves that constitute the core halves and constitute the above-mentioned block 4.

The present invention seeks to provide a manufacturing method for obtaining a set of magnetic heads with uniform characteristics.

FIG. 3 shows a part of the process of the method of the present invention, that is, the process of producing core halves for constructing a composite core. A single-crystal ferrite ingot 10 is sliced into rounds, each slice is processed to have a specific crystal orientation, and a wafer 11 is made.
get. Both sides 11a and 11b of this wafer
A block 14 is obtained by mirror-polishing the wafers 12 and 13 made of polycrystalline ferrite whose opposite surfaces are mirror-polished. That is, this block 14 has a first magnetic body 11 made of a magnetic material suitable for forming the tape contact portion of the magnetic head (single-crystal ferrite in the embodiment, but may also be an alloy such as sendust). Second magnetic bodies 12 and 13 made of a magnetic material (polycrystalline ferrite in the embodiment) suitable for configuring the magnetic circuit section of the head excluding the tape contacting section are bonded together. is further cut along the direction 15 perpendicular to each bonding surface, and as shown in the figure, a wafer 16, which is made of a composite magnetic material and will eventually become the core half of the magnetic head, is cut.
17 can be obtained.

FIGS. 4 and 5 show the process of mirror-polishing each opposing surface of the wafer and then forming various grooves on the polished surface. One wafer 16
The groove 19 defining the track width 18 is placed on the reference surface 2.
Cut parallel to the other wafer 1 at equal pitches from 0.
7 has a groove 21 corresponding to this groove 19 on the reference surface 22.
Similarly, winding grooves 2 are cut at equal pitches and parallel to each other, and winding grooves 2 are cut symmetrically with respect to the first magnetic body 11 and in a direction perpendicular to the track width defining grooves 19 and 21.
2 and 23 are cut, and bonding material insertion grooves 24, 25, 25 are cut on the first magnetic body 11 and the second magnetic bodies 12, 13 in parallel to the winding grooves 23, 23. As shown in FIG. 6, the wafers 16 and 17 which have been grooved in this manner are bonded to bonding material insertion grooves 24, 25, 25 by inserting spacers (not shown) to leave a certain space corresponding to the gap length. A bonding material (for example, glass, not shown) is inserted into the grooves, and the track width defining grooves 19 and 21 are brought into contact with each other so as to face each other. This wafer is then heated under constant pressure. Then, the binding material is in the grooves 19 and 21.
The liquid then flows into the space between the wafers and fills the corresponding area. Thereafter, the temperature is lowered and the wafer 16,
A block 26 is obtained in which the blocks 17 are integrated with a bonding material. This block 26 has surfaces 27 and 2 shown in the figure.
It is divided at 7 and 28, and so-called R polishing is performed to expose curved surfaces 29 and 29. Here, the cut surfaces 27, 27 have an angle (θ) with respect to the plane 30 perpendicular to the abutment surface of the wafer, and therefore, a pair of cut surfaces 27, 27 formed by the cut surfaces 27, 27 and the curved surfaces 29, 29 are formed. As shown in FIGS. 7A and 7B, core chips suitable for mounting at symmetrical positions on a rotating disk of a video tape recorder can be obtained.

In the above embodiment, the wafers 16 and 17 constituting the composite core halves have one first magnetic body 11, but there is also one first magnetic body 11 on the second magnetic body 12 of the block 14 in FIG. A first magnetic body 11 and a second magnetic body 12 are alternately stacked and bonded, cut into wafers, and track width defining grooves and winding grooves are formed on the wafer. The groove and the groove for inserting the bonding material are joined facing each other to obtain the block shown in FIG. 8, and then this block is divided at the surface 31 to obtain a plurality of blocks corresponding to FIG. 6. It's okay.

As described above, according to the present invention, a composite core is provided in which a first magnetic body made of a magnetic material suitable for the tape contact portion of the magnetic head and a second magnetic body made of a magnetic material suitable for the magnetic circuit portion of the magnetic head are combined. It is possible to construct a pair of magnetic heads, which require a symmetrical azimuth angle, in particular the characteristics of the operating gap part, at approximately the same location of the integrated block, that is, on the core chips on both sides of the first magnetic body. It can be useful.

[Brief explanation of the drawing]

FIG. 1A is a plan view of a set of magnetic heads attached to a rotary disk, and FIGS. 1B and 1C are plan views of the magnetic heads of FIG. Second
The figure is a diagram of a conventional composite core manufacturing process. 3 to 6 show a part of the process of the method of the present invention. and fifth
Figures A, B, and C are plan, front, and side views, respectively, of a grooved wafer. FIG. 6 is a perspective view of a block used to explain the process of integrating both wafers and the subsequent dividing process.
FIGS. 7A and 7B are perspective views of a set of core chips cut out from this block. FIG. 8 is an explanatory diagram of another embodiment. 11... first magnetic body, 12, 13... second magnetic body,
19, 21... Track width defining groove, 23, 23... Winding groove, 24, 25, 25... Binding material insertion groove.

Claims (1)

[Claims] 1. A second magnetic body made of a magnetic material suitable for forming the magnetic circuit portion of the magnetic head is attached to the first magnetic body made of a magnetic material suitable for forming the tape contact portion of the magnetic head. a step of joining the blocks so as to sandwich the magnetic material between them; a step of cutting the block obtained by this joining step along a direction perpendicular to the bonding surface; and a step of cutting one of the wafers obtained by this cutting step.
For each set, a groove defining the track width of the magnetic head is machined on one surface of one wafer along a direction perpendicular to the extending direction of the first magnetic body of one wafer, and a groove is machined on one surface of the other wafer. forms a track width defining groove corresponding to the groove, and forms a track width defining groove corresponding to the first groove.
Winding grooves are machined symmetrically with the magnetic material as a boundary and in a direction orthogonal to the track width defining groove, and the first magnetic material is formed on the first and second magnetic materials of one or the other wafer. a step of machining a bonding material insertion groove parallel to the extending direction of the body, and inserting a bonding material into the bonding material insertion groove with a small space between a set of wafers processed in this way; a step of abutting the track width defining grooves so that they face each other, and integrating the set of wafers in this state with the bonding material; A method for manufacturing a magnetic head, comprising the steps of dividing the magnetic head so as to be inclined at an angle corresponding to the azimuth angle of the magnetic head with respect to the mating surface, and further dividing the magnetic head along the bonding material insertion groove.