JPS61158016A - Double azimuth head of vtr and its manufacture - Google Patents

Abstract

PURPOSE:To improve yield by making platelike part constituting a head chip half body a thin Sendust plate. CONSTITUTION:The device is provided with a pair of head chips 51 arranged in parallel in the moving direction X relative to a video tape and different in azimuth angle of magnetic gaps 17, 18. The head chip consists of a magnetic chip half body made up of a base body 20 and a leg 22 and another platelike half body 52 coupled by a principal face on the side of the same direction of the base body 20 and leg 22 relating to the direction of elongation of the leg and the top forms a part of contact face 21 of the tape. The chip half body 52 is made by joining a non-magnetic plate 54 and a thin Sendust plate 55 on the principal faces and joined to a magnetic chip half body 23 to make the non-magnetic plate 54 outside. That is, the non-magnetic plate 54 is positioned on opposite face side of the two head chips 51.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double azimuth gutter in a VTR.

In a VTR (video tape recorder), a signal for one field is recorded on each track running diagonally to the tape running direction on the videotape, and the recording is performed at 180 degrees on a high-speed rotating head drum. This is done using two magnetic heads installed at a distance. Also called the azimuth recording method, these two magnetic heads have different positive and negative azimuth angles to avoid interference between adjacent tracks, and the system extracts signals from tracks with the same azimuth. There is.

It is well known that the videotape is stopped when playing a methyl picture, and the two magnetic heads described above split the track corresponding to each azimuth angle and the track with the opposite azimuth by about half. It becomes a form of reproduction. Therefore, two frames of images are alternately reproduced on the screen, resulting in so-called sluggish operation, and the S/N ratio is degraded because a complete output for one track cannot be obtained. Incidentally, since slow playback is performed by intermittently stopping the videotape, the same problem as above occurs in this case as well.

In order to solve this problem, one of the above two magnetic heads is a normal magnetic head having a positive azimuth angle, and the other is a double azimuth head having both a positive and negative azimuth angle. V
TR has been developed. For normal recording and playback, the negative azimuth side of the double azimuth head and a normal magnetic head are used, and for still image playback and slow playback, the positive azimuth side of the double azimuth head is used. It is something. By doing this, both the normal magnetic head and the double azimuth head can extract signals only from the positive azimuth track during still image playback and slow playback, making it possible to completely eliminate motion blur. . Furthermore, if the stop positions of the video tape for both magnetic heads are accurately set, almost one track's worth can be completely obtained as a reproduced signal output, and the problem of S/H deterioration can be solved.

FIG. 1 shows the above-mentioned conventional magnetic head.

As shown in the figure, the head chip and IH of the magnetic head are
A pair of rectangular magnetic chip halves 2 and 3 are bonded together, and a magnetic gap 4 is formed by depositing a gap spacer made of a non-magnetic material on a portion of the mutual bonding surfaces. A coil window 5 is formed in the head chip l near the magnetic gap 4, and a pair of notches 7 and 8 are provided at both ends corresponding to the coil window 5 and the notch. M pairs of coils 9 and 10 are wound through the portions 7 and 8 such that the center axis of each coil is substantially perpendicular to the tape contact surface 11.

A double azimuth head is shown in FIG.

As shown in FIG. 2, the double azimuth head has a pair of helad chips 15 arranged in parallel in the direction of relative movement with the video tape (not shown): 16. As is clear from Fig. 3, the magnetic gap 1 between both head chips
7 and 18 are each inclined by θ° in the plus and minus directions, in this case about 10°. A pair of Herad chips 15 includes a magnetic chip half body 23 consisting of a base part 20 and a leg part 22 extending in one predetermined direction from the base part and having a tip thereof forming a part of the tape contact surface 21; Another chip half body 24 in the form of a plate whose main surface is joined to the side surfaces of the base body part 20 and the leg part 22 in the same direction in the direction of extension of the part 22, and whose tip part forms a part of the tape contact surface 21. It is composed of.

A gap spacer made of a non-magnetic material is deposited on the bonding surface of each chip half body 23 and 24 and very close to the tape contact surface 21, thereby forming a magnetic gap 17.
18 are formed. Each head chip 15 is provided with a coil window 26 near the magnetic gaps 17 and 18,
Further, a notch 27 is formed at the opposite end of each head chip corresponding to the coil window. These coil windows 2
A coil 28 is attached to the leg portion 22 through the cutout portion 27 and the coil 28.
The coil is wound so that its central axis is substantially perpendicular to the tape contact surface 21. Note that the dimension indicated by S in Figure 2 of the conduit is the separation distance between the magnetic gaps 17 and 18, but this dimension is set extremely small, approximately several hundred μm.
It becomes.

Next, a method of manufacturing the herad tip l (shown in FIG. 1) of the above-mentioned normal magnetic head and the helad tip 15 of the double azimuth head will be described with reference to FIGS. 4 to 8. First, a method for manufacturing a conventional magnetic herad tip 1 will be explained.

As shown in FIG. 4(α), a longitudinal magnetic member 31 whose cross-sectional shape perpendicular to the longitudinal direction is approximately rectangular is formed, and two of the rectangular
A pair of grooves 32 and 33 are formed in the longitudinal direction of the longitudinal magnetic member so that notches are formed on the two long sides. however,
The cross-sectional shape of one groove 32 is approximately trapezoidal;
The cross-sectional shape of No. 3 is approximately rectangular. Next, of each surface of the longitudinal magnetic member 31, the surface on which the grooves 32 are provided is polished, and a surface 34 of the trapezoidal tapered portion side, which is a part of the polished surface and has the cross-sectional shape of the grooves 32, is polished. A non-magnetic material as a gap spacer is deposited on the gap spacer.

On the other hand, as shown in FIG. 4(b), another longitudinal magnetic member 36 is formed whose cross-sectional shape perpendicular to the longitudinal direction is approximately rectangular, and a notch is formed on one of the two long sides of the rectangle. A groove 37 is formed in the longitudinal direction of the longitudinal magnetic member. Thereafter, a surface 38 of each surface of the longitudinal magnetic member 36 opposite to the side on which the groove 37 is formed is polished, and a gap spacer is added to one end 39 of the polished surface in the longitudinal direction. A barrel of non-magnetic material is deposited.

Then, as shown in FIG. 5, both longitudinal magnetic members 31 and 36 are joined with silver solder, for example, on each polished surface.
A longitudinal assembly 41 is formed. As shown by broken lines 42 in FIG. 5, each of the longitudinal magnetic members 31 and 3
The assembly 41 is curved to remove one short side of the rectangle (cross-sectional shape) No. 6 to form a tape contact surface.

Then, as shown by the broken line 43 in FIG.
The assembly 41 is cut to a predetermined size in one longitudinal direction in a direction perpendicular to its longitudinal direction. Thereafter, each cut piece is subjected to finishing processing, and further a coil 7.8 (shown in the first figure) is wound thereon, thereby obtaining a typical Herad tip l of a magnetic head shown in FIG. 1.

Next, the double azimuth head Herad tip 15 (second
4 (α) and (b).
The steps up to and including the steps shown in FIG. 5 are the same as the method for manufacturing the helad tip l of the conventional magnetic head described above.

When the polishing indicated by the broken line 42 in FIG. 5, that is, the formation of the tape contact surface, is completed, the broken line 42 in FIG.
As shown in , most of the longitudinal magnetic member 36 is cut and removed, leaving only the plate-shaped portion 47. Thereafter, as shown by the broken line 48 in FIG. 8, the assembly 41 is cut to a predetermined size in a direction perpendicular to its elongated direction and in its longitudinal direction. Then, each cut piece is subjected to finishing processing, and a coil 28 is further wound to obtain the head chip 15 shown in FIG. 2.

As mentioned above, when manufacturing the Herad chip 15 of the double azimuth head that has already been proposed, the manufacturing process up to the middle is the same as the manufacturing process of the head chip l of a normal magnetic head, and is shown in FIG. By removing most of one longitudinal magnetic member 36, the original shape of the Herad tip 15, which is not yet a cut piece, can be obtained.

Incidentally, the cutting indicated by the broken line 44 in FIG. 7 is performed using a predetermined cutter or the like, and when this cutting is performed, the plate-shaped portion 4 that is the remaining portion of the longitudinal member 36 is cut.
Residual stress was generated in 7, which caused deterioration of various properties.

On the other hand, in response to the recent demand for smaller VTRs and higher performance such as long-duration recording, video tapes made of high magnetic coercivity recording media have begun to be used. Sendust, which has a higher saturation magnetic density than other materials, is often used. However, since sendust has poor workability, forming the plate-shaped portion 47 by cutting the sendust material, which is molded to a certain large size as a so-called raw material, as described above, will result in low retention and cost. There was a problem that the amount of

The present invention has been made in view of the above-mentioned points, and its object is to provide a double azimuth head which is suitable for use in a video tape made of a highly coercive recording medium and is inexpensive. Another object of the present invention is to provide a manufacturing method that does not cause any concern about deterioration of characteristics of the head chip.

A double azimuth head according to the present invention includes a pair of head chips that are arranged in parallel in the direction of relative movement with a video tape and have different azimuth angles of magnetic gaps, and the head chips include a base part and an extension in a predetermined direction from the base part. a magnetic chip half body consisting of a leg portion whose tip portion forms a part of the tape contact surface; The present invention is characterized in that it consists of another plate-shaped magnetic tip half that is joined together and whose tip portion forms part of the tape contact surface, and that the other tip half is made of a Sendust thin plate.

Further, the method for manufacturing a double azimuth head according to the present invention includes a step of forming a longitudinal magnetic member having a substantially rectangular cross-sectional shape perpendicular to the longitudinal direction, and forming a notch on at least one of the two long sides of the rectangle. forming a groove in the longitudinal direction in the longitudinal magnetic member; plane-polishing one side surface of the longitudinal magnetic member corresponding to the long side where the notch is formed; and forming a cross-sectional shape perpendicular to the longitudinal direction. forming a substantially rectangular longitudinal sendust thin plate, plane-polishing one main surface of the longitudinal thin sendust plate, and joining each polished surface of the longitudinal magnetic member and the longitudinal thin sendust plate to form a first child assembly. and polishing the assembly to remove one short side of each rectangle of the longitudinal magnetic member and the longitudinal sendust thin plate to form a tape abutment surface;
The method is characterized in that it includes the step of cutting the assembly in a direction perpendicular to the longitudinal direction and with a predetermined dimension in the longitudinal direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a double azimuth head and a method for manufacturing the same as an embodiment of the present invention will be described with reference to the accompanying drawings. The double azimuth head has the same structure as the double azimuth head shown in FIGS. 2 and 3 except for the parts explained below, and in the following explanation,
The same reference numerals are used for the same parts as in the double azimuth head shown in FIGS.

As shown in FIG. 9, the double azimuth head is arranged in parallel in the relative movement direction: X with the video tape (not shown) and has a magnetic gap of 17.1.
It has a pair of helad chips 51 with different azimuth angles of 8, and a magnetic chip half body 23 consisting of a base part 2o and a leg part 22, and a base part 2o and a leg part in the extending direction of the leg part. It is comprised of another plate-shaped chip half 52 which is joined to each side face of the portion 22 in the same direction at its main surface and whose tip portion forms a part of the tape abutting surface 21 . The chip half body 52 is formed by joining a non-magnetic plate material 54 and a sendust thin plate 55 at their main surfaces, and is coupled to the magnetic chip half body 23 with the non-magnetic plate material 54 on the outside. That is, the non-magnetic plate material 54 is located on each opposing surface side of the two Herad chips 51.

Next, a method for manufacturing the helad tip 51 of the double azimuth head will be described with reference to FIGS. 10 to 12.

Note that in the double azimuth head, part of the manufacturing process, in this case the process for manufacturing the chip half 23, is the same as the manufacturing process for the double azimuth head shown in FIGS. 2 and 3. This process is shown in Figure 4 (
α), and will not be explained here.

While forming the longitudinal magnetic member 31 shown in FIG. 4(a), as shown in FIG. forms a substantially rectangular longitudinal plate member 59. Then, of each surface of the longitudinal plate-like member 59, the main surface formed by the longitudinal sendust thin plate 58 is polished, and then,
A nonmagnetic material as a gap spacer is deposited on one end 60 of the polished surface in the longitudinal direction.

Next, as shown in FIG. 11, the longitudinal magnetic member 31 (
4(a)) and the longitudinal plate member 59 are silver-soldered to each other on each polished surface to form a longitudinal assembly 62. Thereafter, as shown by a broken line 63 in FIG.
The longitudinal assembly 62 is curved to remove one short side portion of the tape assembly 62 to form a tape contact surface. The longitudinal assembly 62 is then cut perpendicular to its longitudinal direction and to a predetermined length in the longitudinal direction, as shown by dashed line 64 in FIG. Thereafter, each cut piece is subjected to finishing processing, and a coil 28 (shown in FIG. 9) is wound thereon to obtain a head chip 51 shown in FIG. 2.

In addition, the longitudinal sendust thin plate mentioned above can be produced by sputtering,
It is formed by vacuum evaporation or melt ultra-quenching method.

Effects of the Invention As detailed above, in the method for manufacturing a double unmasked head according to the present invention, the longitudinal magnetic member (31) and the longitudinal thin sendust plate (58) are bonded (however, in the embodiment, the longitudinal thin plate is bonded to the thin longitudinal sendust plate). The original shape of the head chip (51) is formed by simply joining the longitudinal plate-like member 59 formed by joining the magnetic plates 54 to the longitudinal magnetic member 31. Therefore, as in the already developed method of manufacturing a double azimuth head, a pair of longitudinal magnetic members (indicated by reference numerals 31 and 36 in FIG. 4) are joined together.
Residual stress due to forming the original shape of the head chip (15) by cutting off most of one of them (longitudinal magnetic member 36) is not generated.

In addition, in the double azimuth head according to the present invention, as mentioned above, the plate-shaped portion forming the half of the head chip is made of a Sendust thin plate (55), and this Sendust thin plate is formed in advance into a plate shape by sputtering, for example, and is compared to a conventional double azimuth head in which the plate-shaped part is formed by cutting a sendust material that has been formed to a certain large size as a material. As a result, the yield rate is high, making it easier to reduce costs.

[Brief explanation of drawings]

Fig. 1 is a plan view of a normal magnetic head, Fig. 2 is a plan view of a double azimuth head that has already been developed, Fig. 3 is a view taken along arrows I-III in relation to Fig. 2, and Figs. 4 to 8 are 9 is a plan view of the double azimuth head according to the present invention. FIGS. 10 to 12 are diagrams for explaining the manufacturing method of the double azimuth head. It is a figure for explaining. Explanation of symbols of main parts 20...Base portion 21...Tape contact surface 2
2... Leg portion 23.52... Chip half body 51... Dochig 54... Non-magnetic plate material 55
...Sendust thin plate 57...Longitudinal non-magnetic plate material 58
・・・Longitudinal sendust thin plate

Claims (5)

[Claims] (1) It includes a pair of head chips that are arranged in parallel in the direction of relative movement with the video tape and have different azimuth angles of magnetic gaps, and the head chips include a base part and a tip end thereof extending in a predetermined direction from the base part. a magnetic chip half body consisting of a leg portion forming a part of the tape contact surface; and another plate-shaped magnetic chip half whose part forms part of the tape contact surface,
A double azimuth head characterized in that the other chip half is made of a Sendust thin plate. (2) Claim 1, characterized in that the sendust thin plate is obtained by sputtering.
Double azimuth head as described in section. (3) The double azimuth head according to claim 1, wherein the sendust thin plate is obtained by vacuum deposition. (4) The double azimuth head according to claim 1, wherein the sendust thin plate is obtained by a melt ultra-quenching method. (5) forming a longitudinal magnetic member having a substantially rectangular cross-sectional shape perpendicular to the longitudinal direction, and grooves in the longitudinal direction so that a notch is formed in at least one of the two long sides of the rectangle; a step of plane-polishing one side surface of the longitudinal magnetic member corresponding to the long side where the notch is formed; and a step of forming a longitudinal sendust thin plate having a substantially rectangular cross-sectional shape perpendicular to the longitudinal direction. a step of plane-polishing one main surface of the longitudinal thin thin plate of thin longitudinal sendust; a step of joining each polished surface of the thin longitudinal magnetic member and the thin thin longitudinal thin plate of longitudinal senddust to form a longitudinal assembly; polishing the assembly to form a tape contact surface by removing one short side of each rectangle of the thin plate; and polishing the assembly in a direction perpendicular to the longitudinal direction and with a predetermined dimension in the longitudinal direction. A method for manufacturing a double azimuth head, comprising the step of cutting.