JPH064821A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To improve the output characteristic at the time of reproduction by chamfering magnetic metallic thin films to a straight shape at both ends of a magnetic gap, thereby regulating a track width. CONSTITUTION:A front gap is formed across front surfaces 1b, 2b of respective auxiliary core parts 1, 2 and a back gap is formed from the rear end face of a winding groove to the back side, i.e., the rear surfaces 1c, 2c of the respective auxiliary core parts 1, 2. Track width regulating grooves 6, 7 are so bored that the magnetic gap is regulated to the prescribed track width Tw on both surfaces of the butt surfaces 1a. These regulating grooves 6, 7 are so formed to a nearly arc shape in section from the front surfaces 1b, 2b of the core parts 1, 2 to the rear surfaces 1c, 2c. Both ends of the butt surfaces of the magnetic metallic thin films 3, 4 are chamfered to the straight shape by regulating the width Tw of the track of the magnetic gap and are formed to a nearly V shape in section. Consequently, the leakage of the magnetic fluxes in parts exclusive of the butt surfaces is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head mounted on a magnetic recording / reproducing apparatus such as a video tape recorder (VTR).

[0002]

2. Description of the Related Art For example, a video tape recorder (hereinafter referred to as
In a magnetic recording / reproducing apparatus such as a VTR), a short wavelength recording of an information signal has been promoted for the purpose of high image quality and the like.
Accordingly, in the field of media for recording information signals as magnetic signals, that is, in the field of magnetic recording media such as magnetic tapes, so-called metal tapes using ferromagnetic metal powders as magnetic powders or ferromagnetic films on base films are used. A magnetic recording medium having a high coercive force such as a so-called vapor-deposited tape directly coated with a metal powder has been used.

On the other hand, research has also been conducted in the field of magnetic heads to cope with this problem. For example, as shown in FIG. 7, magnetic core halves 11 and 12 made of a magnetic material have a high saturation magnetic flux density. Magnetic thin films 13 and 14 are arranged,
A so-called metal-in-gap type magnetic head has been developed in which the abutting portion of the metal magnetic thin films 13 and 14 is a magnetic gap g. As a magnetic head suitable for the above-mentioned high coercive force magnetic recording medium, a VTR or the like is used. Has been put to practical use in the magnetic recording / reproducing apparatus.

[0004]

By the way, as a method of forming a metal magnetic thin film on a magnetic core half body, conventionally, a vacuum deposition method, a sputtering method, an ion plating method,
A film forming method using a vacuum thin film forming technique typified by a cluster ion beam method is known. However,
In the magnetic head manufactured by applying these film forming methods, when recording / reproducing an information signal, the magnetic gap g
The magnetic gap g is actuated wider than the track width Tw, which is an important problem in promoting shorter wavelength recording.

That is, when the metal magnetic thin film is formed by the above-described film forming method, the magnetic material for the metal magnetic thin film (hereinafter, referred to as the core material) applied to the magnetic core half body (hereinafter, referred to as the core material) , Abbreviated as thin film material), for example, as shown in FIG. 7, both ends of the abutting surfaces 13a and 14a of the metal magnetic thin films 13 and 14, so-called track edges are rounded, that is, the abutting surfaces. Thirteen
The portions a, 14a and the track width regulating grooves 15, 16 are formed in a curved shape having a substantially arc shape. As a result, the magnetic flux leaks not only between the abutting surfaces 13a and 14a but also from the rounded track edge (so-called,
Fringing phenomenon. ), That is, the magnetic flux leaks wider than the predetermined track width Tw of the magnetic gap g, and the erasing action occurs.

Generally, in a magnetic recording / reproducing apparatus such as a consumer video tape recorder (hereinafter abbreviated as VTR), a recording system called so-called azimuth recording is adopted in order to achieve high density recording. Is increasing.
This is formed by the magnetic head having a magnetic gap g having an angle .theta. (So-called azimuth angle .theta.) With respect to the side surface of the magnetic core half body, whereby an information signal as shown in FIG. Is recorded with an inclination with respect to the traveling direction of the magnetic recording medium 17 such as a magnetic tape, that is, with a long track width for recording a large amount of information on one track. Here, when two magnetic heads having different azimuth angles θ are mounted, magnetic anisotropy is generated on the surface of the magnetic recording medium on which information is recorded, that is, the magnetic layer due to the azimuth angles θ, and a so-called guard band is unnecessary. (In other words, crosstalk between adjacent tracks A and B can be prevented.) As a result, higher density recording can be achieved.

However, when the above-mentioned magnetic head is mounted on the magnetic recording / reproducing apparatus adopting the azimuth recording method and the recording medium is recorded / reproduced on the magnetic recording medium, the magnetic head is wider than the predetermined track width Tw of the magnetic gap g. The magnetic gap g is actuated, that is, the information signal is recorded with the track width Tw ₁ wider than the predetermined track width Tw as shown in FIGS. 7 and 8A. The erasing action is generated wider than Tw _1, and as a result, the previously recorded information, that is, a part of the track B area is erased. Therefore, it goes without saying that the output characteristic of the recording track B is deteriorated during reproduction.

Further, in the manufacturing process (or inspection process) of the magnetic head, the dimension of the track width Tw of the magnetic gap g is optically / artificially measured by using, for example, an optical microscope, an image processing device or the like. ing. However, as described above, since both ends of the abutting surface of the metal magnetic thin film have an arc shape, a measurement error occurs in the dimension measurement, and a magnetic head having an accurate / predetermined track width Tw is obtained. It is also difficult to manufacture, and the so-called fringing phenomenon in which the track width Tw ₁ operates wider than the predetermined track width Tw has not been solved yet.

As described above, in the conventional metal-in-gap type magnetic head, both ends of the abutting surface of the metal magnetic thin film, so-called track edges, are formed in a curved / arcuate shape. When recording a signal, the erasing action on a track on which information has already been recorded is enhanced, and when reproducing an information signal, the output characteristic is reduced, and improvement thereof has been awaited.

Therefore, the present invention has been proposed in view of such conventional circumstances, and regulates the track width Tw of the magnetic gap g, that is, reduces the erasing action on an adjacent track at the time of recording, and the output characteristics at the time of reproduction. It is an object of the present invention to provide a magnetic head that can be improved.

[0011]

Means for Solving the Problems The inventors of the present invention have made earnest studies as to achieve the above-mentioned object, and as a result, applied a bias sputtering method to a substrate made of a magnetic material or the like, that is, an abutting surface of a magnetic core half body. It has been found that when a metal magnetic thin film is formed on the metal magnetic thin film, both ends of the abutting surface of the metal magnetic thin film are chamfered linearly to secure a predetermined track width Tw.

The present invention has been completed on the basis of such knowledge, and a metal magnetic thin film is arranged at the abutting portion of at least one magnetic core half body, and these magnetic core half bodies are butted to each other. In a magnetic head having a closed magnetic circuit and a magnetic gap formed on the abutting surface of the metal magnetic thin film, the metal magnetic thin film is chamfered linearly at both ends of the magnetic gap to regulate the track width. It is characterized by that.

Further, in the manufacturing method of the present invention, the magnetic core half body formed by forming the metal magnetic thin film on the substrate on which the track width regulating groove is formed is integrally joined with another magnetic core half body through the gap material. In the method of manufacturing a magnetic head, the metal magnetic thin film is formed by a bias sputtering method.

[0014]

In the present invention, both ends of the abutting surface of the metal magnetic thin film are chamfered linearly, that is, formed to have a substantially V-shaped cross section, so that an information signal can be recorded with a predetermined track width Tw. It is possible to reduce the degaussing / erasing action on the adjacent tracks during recording, and prevent the output from decreasing during reproduction.

Further, since the bias sputtering method is applied in the manufacturing method of the present invention, a metal magnetic thin film having a predetermined track width Tw can be formed with high precision, and
In the manufacturing process (or inspection process) of the magnetic head, the track width Tw can be easily measured / inspected,
Work (inspection) efficiency can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. The magnetic head of this embodiment has auxiliary core portions 1 and 2 as shown in FIGS.
And a pair of magnetic core halves I composed of the metal magnetic thin films 3 and 4,
Reference numeral II is a closed magnetic circuit formed by abutting and integrating the metal magnetic thin films 3 and 4 with each other.

As shown in FIG. 1, the auxiliary core portions 1 and 2 are
For example, it is formed of an oxide magnetic material such as Mn-Zn ferrite or Ni-Zn ferrite and is formed in a substantially rectangular flat plate shape. A winding groove 5 having a substantially trapezoidal cross section, on which a winding for supplying a signal to the magnetic head or for extracting a signal from the magnetic head is wound, is formed on the abutting surface 1a of one auxiliary core portion 1, which will be described later. The magnetic gap g (front gap) is formed by limiting the depth length Dp. As a result, on the abutting surface 1a, from the upper end surface of the winding groove 5 to the front side, that is, each auxiliary core portion 1,
A front gap is formed over the upper surfaces 1b and 2b of the second winding 2, and a back gap is formed from the lower end surface of the winding groove 5 to the back side, that is, the lower surfaces 1c and 2c of the auxiliary core portions 1 and 2.

Further, on both sides of the abutting surface 1a, a track width regulating groove 6 is formed in consideration of the thickness of a metal magnetic thin film which will be described later so as to regulate a magnetic gap g which will be described later to a predetermined track width Tw. 7 is drilled. These track width regulating grooves 6, 7 extend from the front side to the back side, that is, from the upper surfaces 1b, 2b to the lower surface 1 of each auxiliary core portion 1, 2.
It is formed to have a substantially arcuate cross section from c to 2c. Of course, the shape of the track width regulating grooves 6 and 7 is not limited to the above-mentioned shape, that is, a substantially arcuate cross section, and may be a substantially V-shaped cross section or the like depending on the required characteristics of the magnetic head.

The metal magnetic thin film 3 having a high saturation magnetic flux density and an excellent soft magnetic characteristic is formed over the entire butting surfaces 1a, 2a including the winding groove 5 and the track width regulating grooves 6, 7 described above. 4 are deposited by the bias sputtering method. The metal magnetic thin films 3 and 4 are made of Fe-Al.
-Si alloy, Fe-Si alloy, Fe-Ni alloy,
A conventionally known magnetic material such as an Fe-Ga-Si-Ru-based alloy, a Co-Nb-Nd-based alloy, or a Co-Nb-Ta-based alloy may be used.

As a result, the magnetic core halves I and II are formed.

In particular, in this embodiment, both ends of the abutting surfaces 3a, 4a of the metal magnetic thin films 3, 4 described above are chamfered linearly by restricting the track width Tw of the magnetic gap g, and the cross section is approximately V. It is formed in a letter shape. As a result, leakage of magnetic flux other than between the abutting surfaces 3a and 4a, so-called fringing phenomenon is suppressed, and the magnetic gap g is wider than the predetermined track width Tw of the magnetic gap g, that is, the magnetic recording medium as in the conventional magnetic head. For a predetermined track width T
It is possible to eliminate the operation of the magnetic gap g with the track width Tw ₁ for performing recording / erasing or the like greater than w. Therefore, it goes without saying that it is possible to reduce the degaussing action on the adjacent track when recording the information signal, and the reduction in output when reproducing the information signal.

Then, these magnetic core halves I and II are
The metal magnetic thin films 3 and 4 are butted against each other through a gap film (not shown) made of a non-magnetic material such as an amorphous alloy such as SiO ₂ so that the abutting surface 3a of the metal magnetic thin films 3 and 4 is abutted. Magnetic gap g between 4a
Are formed to constitute the magnetic head. The track width regulating grooves 6 and 7 are filled with a non-magnetic material such as the above-mentioned amorphous alloy in order to secure the contact with the magnetic recording medium. Further, in order to secure the contact characteristics, the sliding characteristics, etc. between the magnetic head and the magnetic recording medium, the magnetic recording medium sliding contact surface 1b facing the front side of each auxiliary core portion 1, 2, that is, the magnetic recording medium, 2b
Is polished in an arc shape until one end surfaces of the metal magnetic thin films 3 and 4 are exposed.

By the way, the above-mentioned magnetic head is manufactured as follows. In manufacturing the magnetic head of the present embodiment, first, as shown in FIG. 3, a rectangular rectangular planar core block 1d made of an oxide magnetic material is prepared. The main surface 1a of the core block 1d, that is, the joint surface 1a when the core blocks are abutted to each other
Further, the track width regulating groove 6 having a substantially arcuate cross section as shown in FIG. 4 is formed over the entire width of the joint surface 1a by a mechanical means such as a rotary grindstone. Furthermore, core block 1
In d, a winding groove 5 for winding a winding is formed by a rotary grindstone or the like so as to be substantially orthogonal to the track width regulating groove 6 as shown in FIG.

Next, the flat surface between the track width regulating grooves 6, that is, the magnetic gap g forming surface 1a is mirror-finished. At this time, it goes without saying that the magnetic gap forming surface 1a is provided with a predetermined predetermined dimension in consideration of the thickness of the metal magnetic thin film described later and the like. Further, for example, the track width regulation groove 6 forming surface 6a and the magnetic gap g forming surface 1
The burr formed on the ridgeline formed by a is also removed.

Then, as shown in FIG. 5, a metal magnetic thin film 3 is deposited over the entire one main surface 1a of the core block 1d including the above-mentioned grooves. Here, the bias sputtering method is applied so that the metal magnetic thin film 3 regulates a predetermined track width Tw, that is, the predetermined track width Tw is regulated so that both ends of the abutting surface 3a are chamfered linearly. To film.

In this bias sputtering method, for example, a negative bias voltage is applied to the substrate, that is, a negative potential is concentrated on the substrate surface, and the thin film is formed at a speed V _M and the thin film is removed (so-called flattening). That is, a flat thin film is formed by controlling the balance of the velocity V _E. Therefore, if the above-mentioned metal magnetic thin film 3 is formed on one main surface 1a of the core block 1d by applying this bias sputtering method, by applying a negative bias voltage to the core block 1d, the core block 1d can be formed. The negative potential is concentrated on the one main surface 1a, that is, the ridge angle at which the magnetic gap forming surface 1a and the track width regulation groove 6 forming surface 6a intersect, and as a result, on the magnetic gap forming surface 1a as shown in FIG. Speed V _E at which the metal magnetic thin film 3 is removed
On the other hand, since the speed V _M at which the metal magnetic thin film 3 is formed is high (V _E <V _M ), the flat metal magnetic thin film 3 is formed and the magnetic gap forming surface on which the negative potential is concentrated is formed. At the ridge angle at which 1a intersects with the track width regulation groove 6 forming surface 6a, the speed V at which the metal magnetic thin film 3 is similarly removed
_{Although the} speed V _{M at} which the metal magnetic thin film 3 is formed with respect to _E is high (V _E <V _M ), the difference is smaller than that of the former, so that the metal magnetic thin film 3 has the magnetic gap forming surface 1.
The side edge of a is formed in a linear shape, that is, the side edge is chamfered in a linear shape.

At this time, the negative bias voltage applied to the core block 1d varies depending on the voltage capacity of the power supply device and the like. When a power supply device having a power capacity of 1 kw is used, for example, an electric power of 700 w within an allowable amount is used. Use
A negative bias voltage of about 250V is applied to the core block 1d. Of course, it is needless to say that a higher negative bias voltage can be applied by using a power supply device having a large power capacity, which further flattens the side edge of the metal magnetic thin film 3 on the abutting surface 3a, that is, the accuracy of the track width Tw. Can be expected to increase.

As the material of the metal magnetic thin film 3, a ferromagnetic material having a high saturation magnetic flux density and an excellent soft magnetic property is used. Can also be used, and if exemplified, Fe
-Al-Si type alloy, Fe-Si type alloy, Fe-Ni type alloy, Fe-Ga-Si-Ru type alloy, Co-Nb-N
Examples include d-based alloys and Co-Nb-Ta-based alloys.

The operations described above are repeated to create the core block 2d. At this time, it is not necessary to form a groove portion corresponding to the winding groove in the core block 2d.

As shown in FIG. 6, the core blocks 1d and 2d are formed by using the metal magnetic thin films 3 and 4 as joint surfaces.
The track widths Tw are matched with each other, that is, with the magnetic gap g forming surfaces 1a and 2a facing each other. As a result, the ferrite blocks 1d and 2d are joined and integrated. Then, the front surfaces 1c, 2c of the ferrite blocks 1d, 2d corresponding to the sliding surfaces of the magnetic recording medium are cylindrically polished, and finally, slicing is performed at the cutting position shown by the broken line in FIG. Complete the head.

Although one embodiment of the present invention has been described above, various modifications can be made without departing from the spirit of the present invention.

[0032]

As is apparent from the above description, according to the present invention, the metal magnetic thin film is arranged at the abutting portion of at least one magnetic core half body, and these magnetic core half bodies are abutted with each other. In a magnetic head in which a closed magnetic path is formed by and a magnetic gap is formed on the abutting surface of the metal magnetic thin film, the metal magnetic thin film is chamfered linearly at both ends of the magnetic gap, The fringing phenomenon of the magnetic gap g can be eliminated by being restricted by the track width Tw, and the degaussing action on the adjacent track at the time of recording the information signal and the reduction of the output at the time of reproducing the information signal can be reduced.

Further, according to the manufacturing method of the present invention, the magnetic core half body formed by forming the metal magnetic thin film on the substrate in which the track width regulating groove is formed is passed through another magnetic core half body and the gap member. In a method of manufacturing a magnetic head that is integrally bonded,
Since the metal magnetic thin film is formed by the bias sputtering method, the metal magnetic thin film is formed with high accuracy by controlling the predetermined track width Tw, so that the above-mentioned pseudo-gap effect can be eliminated and the manufacturing process can be improved. The dimension measurement / inspection of the track width Tw in the process or the inspection process can be facilitated, and the work / inspection efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of a magnetic head according to the present invention.

FIG. 2 is a plan view of an essential part of an embodiment of a magnetic head according to the present invention.

FIG. 3 is a schematic perspective view showing a core block, showing an example of a method of manufacturing a magnetic head according to the present invention in the order of steps.

FIG. 4 is a schematic perspective view showing a step of forming a track width regulating groove and a winding groove on one main surface of the core block.

FIG. 5 is a schematic perspective view showing a step of depositing and forming a metal magnetic thin film on one main surface of a core block.

FIG. 6 is a schematic perspective view showing a step of joining and integrating a pair of core blocks.

FIG. 7 is a plan view of a main part of a conventional magnetic head.

FIG. 8 is a schematic diagram showing a state in which a conventional magnetic head has accessed a magnetic recording medium.

[Explanation of symbols]

 I, II ・ ・ ・ Magnetic core half body 1, 2 ・ ・ ・ Auxiliary core portion 3, 4 ・ ・ ・ Metal magnetic thin film 5 ・ ・ ・ Winding groove 6, 7・ Track width control groove

Claims (2)

[Claims] 1. A magnetic metal thin film is arranged at the abutting portion of at least one magnetic core half, and a closed magnetic path is formed by abutting these magnetic core halves, and the abutting surface of the metallic magnetic thin film is formed. 2. A magnetic head having a magnetic gap formed in, wherein the metal magnetic thin film is chamfered linearly at both ends of the magnetic gap, and the track width is regulated. 2. A method of manufacturing a magnetic head in which a magnetic core half body formed by forming a metal magnetic thin film on a substrate having a track width regulating groove is joined and integrated with another magnetic core half body via a gap material. 2. The method of manufacturing a magnetic head according to claim 1, wherein the metal magnetic thin film is formed by a bias sputtering method.