JPS6329325B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite magnetic head that integrally includes a recording and/or reproducing gap and an erasing gap.

Recently, there has been an increasing need for editing such as replacing information only in the necessary parts with VTRs and magnetic disks, etc., and in order to erase and rewrite each field and each channel, a recording/playback gap 1 is required as shown in Figure 1. In order to obtain a desired track width 2, the erase gap 6 is narrowed down by the notch holes 3 and 4 that define the width and is spaced apart from the recording/reproducing gap by a predetermined distance 5, and the erase gap 6 is widened to the full width 7. Proposed. However, with this configuration, there is a limit to reducing the total width of the magnetic head from the viewpoint of wear resistance, so the erase track width cannot be further reduced.
Therefore, even if the track width 2 of the recording/reproducing gap that is forced by the notches 3 and 4 is reduced, the track pitch must be increased in order to erase only that track, thus achieving the goal of high density. Can not. Therefore, in order to eliminate this drawback, it is conceivable to provide the erase gap with a cutout hole that defines the track width in the same way as in the case of the recording/reproducing gap, but in order to ensure the erase operation, the entire width of the erase gap is recorded. It is necessary to make the track width larger than the track width of the regenerating gap, which has been a difficult point in manufacturing. That is, as shown in FIG.
To make the track width 2 larger than the track width 2, the shape of the notch holes 10 and 11 that define the overall width 9 is changed to the shape of the notch holes 10 and 11 that define the track width 2. This is because it was thought that the cutter blade had to be different from that of No. 4, and the cutter blade or the feed pitch etc. had to be changed during each gap molding.

By devising the shape of each core constituting the composite magnetic head, the present invention enables efficient processing without changing the conditions for forming the notch holes that define the track width, and is inexpensive. Moreover, it is an object of the present invention to provide a method for manufacturing a composite magnetic head suitable for narrowing the track.

FIG. 2 shows a plan view of one embodiment of the composite magnetic head of the present invention. In the figure, reference numeral 12 denotes a central core constituting a common magnetic path for recording, reproducing and erasing operations, and its length 5 is selected to be approximately 0.8 to 1.0 [mm]. Reference numeral 13 denotes a first core that constitutes a magnetic path for recording and reproducing together with the central core 12, and this first core has a total thickness 7 of approximately 160 [μm] in order to define a track width 1 of approximately 60 [μm]. Notch holes 3 and 4 are provided symmetrically from both sides as shown. 14 and 15 are central core 1
2 and the first core 13, the notch holes 3 and 4 are filled with the glass body at the same time. Incidentally, the gap length of the recording/reproducing gap 1 is selected to be approximately 0.4 [μm], and the total length 16 of the first core 13 is selected to be approximately 1.5 [mm].

Reference numeral 17 denotes a second core that constitutes a magnetic path for erasing operation together with the central core 12. In order to define the track width 8 of approximately 66 [μm], this second core 17 also has cut holes as shown in the figure from both sides. 10 and 11 are provided. This second core 17 is spaced approximately 20 to 30 [μ] from the center core 12 (elimination gap length).
They are fused together by glass bodies 18 and 19 with a gap in between. The total length 20 of the second core 17 is determined by the length 20 of the second core 17 in order to leave different track widths 1 and 8 on the first and second cores 13 and 17 under the same cutting conditions, as will be described later.
It is set slightly smaller than that of the core 13 (approximately 1.5 [mm]).

Next, the main steps for constructing such a composite magnetic head will be explained. Figure 3 shows the first core 1
FIG. 4 shows a state in which a predetermined groove has been formed on the first wafer 21 constituting the second core 17, and FIG. There is. Thickness 23 of first wafer 21
is formed to be slightly larger than the thickness 24 of the second wafer 22. These cutter blades 2 are placed on the same reference plane and have the same shape as shown enlarged in Fig. 5.
5, when grooves are formed to define the track width, the track width for the first wafer 21 is
T ₁ and groove width W ₁ can be formed, and for the second wafer 22, the track width can be
Groove 27 with T ₂ and groove width W ₂ (T ₁ +W ₁ =T ₂ +W ₂ )
can be formed. Therefore, the first and second
As shown on wafers 21 and 22, grooves 26 and 27 for forming different notch holes 3 and 10 can be obtained under the same cutting conditions. _D1 , _D2
indicates the respective grinding depths of the first and second wafers 21 and 22, and θ is the inclination angle (45°) of the blade surface. Incidentally, on each wafer 21, 22, non-magnetic layers 28, 29 for defining the gap length, coil winding grooves 30,
31 and glass filling grooves 32, 33, etc., are also formed, but these are no different from the conventional ones.

FIG. 6 shows first and second wafers 21 and
22 is shown. groove 32,3
The glass rod 35 inserted into the wafer 3 is melted and solidified to fill the grooves 26 and 27 of the first and second wafers 21 and 22 and the gaps between each wafer with the glass body, and also to integrate each wafer. . This is A-A', B-B',
The block is cut along C--C', and then polished so that the tape contact surface 36 has a predetermined shape and the gap depth 37 has a desired depth, as shown in FIG. After that, as shown in Figure 8,
On this tape abutting surface, grooves 38 are sequentially ground so as to define the core total thickness 7 and leave notch holes 3, 10 symmetrically, and then D-D', E-E', . . . The composite magnetic head shown in FIG. 9 is obtained by slicing along the lines. Incidentally, FIG. 2 shows a plan view of the tape abutting surface of this composite magnetic head.

As mentioned above, in the present invention, the erasing gap is also provided with a cutout hole for defining the track width in the same way as the recording/reproducing gap, so that it is possible to use a recording/reproducing track with a narrow track pitch to cover an adjacent track without impairing wear resistance. Erasing can be performed without erasing, and since the overall length of the erasing core (second core) is slightly shorter than that of the recording/reproducing core (first core), the cutting operation for forming the notched hole is There is no need to change the first and second cores individually, and it is possible to provide a method of manufacturing a composite magnetic head that is suitable for mass production and is inexpensive.

[Brief explanation of the drawing]

Figure 1 is a plan view of the conventional tape contact surface;
The figure is a plan view of the tape abutting surface of one embodiment of the present invention. 3 and 4 show the first and second wafers, and in each figure, A is a plan view and B is a side view. FIG. 5 is an explanatory diagram of the cutting operation, and FIG. 6 is a perspective view showing the process of integrating each layer. 7 and 8A and 8B are explanatory views of the molding process, and FIG. 9 is a perspective view of the configuration of the composite magnetic head. Explanation of main drawing numbers 12...Central core, 13...1st
Core, 14...second core, 16, 20...first, second
Each total length of the core.

Claims (1)

[Claims] 1. A first wafer made of an oxide magnetic material and a second wafer made of an oxide magnetic material and having a different thickness from the first wafer are placed on the same reference surface, and the first wafer and the second wafer are A strip structure with different groove widths is formed on the upper surface by cutter blades of the same shape, and a coil winding groove and a glass filling groove are formed on the upper surfaces of the first wafer and the second wafer, which are substantially orthogonal to the strip structure. After the first step, the top surface of the first wafer and one surface of the center wafer are brought into contact with each other through a non-magnetic layer that defines a gap length, and the second wafer is The upper surface and the other surface of the central wafer are brought into contact with each other through a non-magnetic layer that defines a gap length, and the glass filled in the glass filling groove is melted and solidified to melt and solidify the glass filled in the first glass filling groove.
a second step of integrating the wafer and the second wafer by sandwiching the center wafer to form a block; and a third step of cutting the block to form a magnetic head core after the second step is completed. A method for manufacturing a composite magnetic head, comprising: