JPH05225513A - Magnetic head - Google Patents

Abstract

PURPOSE:To considerably improve the magnetic characteristics of thin magnetic metal films formed in winding grooves. CONSTITUTION:A closed magnetic path is formed by disposing a pair of halves 1, 2 of a magnetic core composed separately of ferrite substrates 7, 8 with formed winding grooves 9, 10 and thin magnetic metal films 3, 4 formed along the opposite surfaces of the substrates 7, 8 including the insides of the grooves 9, 10 so that the metal films 3, 4 are butted on each other. The winding grooves 9, 10 formed in the halves 1, 2 are made asymmetric.

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, for example, a video tape recorder (VTR), and more particularly to the shape of a winding groove.

[0002]

2. Description of the Related Art For example, in a magnetic recording / reproducing apparatus such as a VTR, a shorter wavelength recording of an information signal has been promoted for the purpose of improving the image quality, whereas a ferromagnetic metal powder is used as the magnetic powder. In addition, a high coercive force magnetic recording medium such as a so-called metal tape or a vapor deposition tape in which a ferromagnetic metal material is directly deposited on a base film has been used.

On the other hand, research has also been advanced in the field of magnetic heads to deal with this, and a so-called metal-in-type magnetic head using a metal magnetic material as a magnetic head suitable for a high coercive force magnetic recording medium. Various gap type magnetic heads have been developed.

As an example of the magnetic head, for example, FIG.
It is known that it is constructed as shown in FIG. Such a magnetic head includes a pair of magnetic core halves 107, 108 formed by forming metal magnetic thin films 105, 106 on the abutting surfaces of substrates 103, 104 made of ferrite or the like in which winding grooves 101, 102 are formed. A closed magnetic circuit is formed by abutting the metal magnetic thin films 105 and 106 as the abutting surfaces.

Usually, in a magnetic head, a ferrite block substrate is formed by forming winding grooves having a substantially U-shaped cross section and a track width regulating groove having an arc cross section on one ferrite block substrate and then dividing the ferrite block substrate into two parts. It is formed by joining and integrating ferrite block substrates. Therefore, the winding grooves 101 provided in the magnetic core halves 107 and 108,
The shape of 102 is generally symmetrical. The magnetic gap g of the winding grooves 101 and 102 is
Side walls 101a that serve to control the depth of the
The angle θ formed by 102a is approximately 90 degrees. That is, the side walls 101a and 102a and the metal magnetic thin film 105,
The angles θ ₁ and θ ₂ formed by the abutting surfaces S of 106 are both about 45 degrees.

However, when the applicant of the present invention examined the magnetic characteristics of the above magnetic head, the side wall surface 101 was set at 45 degrees.
a, a magnetic thin film 105, 10 formed on 102a
It was found that the magnetic characteristics of No. 6 are deteriorated as compared with the magnetic characteristics of the metal magnetic thin films 105 and 106 formed on a flat surface such as the abutting surface S between the metal magnetic thin films 105 and 106. did. Therefore, although the metal magnetic thin films 105 and 106 are used as auxiliary core materials for the purpose of improving the magnetic characteristics, sufficient reproduction characteristics cannot be obtained. Therefore, the recording / reproducing on the high coercive force magnetic recording medium becomes insufficient, and it is the current situation that it is not possible to cope with the high image quality required for VTR and the like.

[0007]

Therefore, the present invention has been proposed in order to solve the above-mentioned technical problems, and it is possible to improve the magnetic characteristics of a metal magnetic thin film formed in a winding groove. It is an object of the present invention to provide a magnetic head having high reproduction efficiency.

[0008]

In order to achieve the above-mentioned object, the present invention provides a substrate made of an oxide magnetic material in which winding grooves are formed, and a butt surface including the inside of the winding grooves of the substrate. A pair of magnetic core halves made up of metal magnetic thin films formed along the above, forming a closed magnetic path by abutting the metal magnetic thin films to each other. The winding groove to be formed is asymmetric in shape.

[0009]

In the magnetic head according to the present invention, since the winding grooves formed in the pair of magnetic core halves are asymmetrical in shape, the metal magnetic thin film formed in the winding grooves is transparent. The magnetic susceptibility is increased and the reproduction efficiency is improved.

[0010]

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. In the magnetic head of the present embodiment, as shown in FIG. 1, a pair of magnetic core halves 1 and 2 which are separately manufactured on the left and right with a magnetic gap g acting as a recording / reproducing gap as a boundary are metal magnetic thin films of each other. 3 and 4 are abutted to form a closed magnetic circuit, and are fused and integrated by the fused glasses 5 and 6.

The magnetic core halves 1 and 2 are made of Mn-, for example.
The substrates 7 and 8 are made of an oxide magnetic material such as Zn ferrite or Ni-Zn ferrite, and the metal magnetic thin films 3 and 4 are formed along the abutting surfaces of the substrates 7 and 8. A winding for winding a coil for supplying an electric signal based on recording information to the head and transmitting a magnetic signal from the medium as an electric signal to the apparatus side in the middle of the abutting surfaces of the substrates 7 and 8. Grooves 9 and 10 are formed. Further, in the substrates 7 and 8, track width regulating grooves 11 and 1 for regulating the track width Tw of the magnetic gap g.
2 is formed. The track width regulating grooves 11 and 12 are
Grooves having substantially arcuate plane shapes are formed at both ends of the magnetic gap g only on the magnetic recording medium sliding contact surface 13 side. In addition, the magnetic recording medium sliding contact surface 13 of the substrates 7 and 8
The width W is regulated in order to secure a good contact property with the magnetic recording medium. That is, steps 14 and 15 are provided by scraping off both edges of the upper end surfaces of the substrates 7 and 8 along the running direction of the magnetic recording medium, and the steps W and W of the magnetic recording medium sliding contact surface 13 are provided by these steps 14 and 15. Is regulated. The winding grooves 9 and 10 are formed on the abutting surfaces of the substrates 7 and 8 thus formed.
The metal magnetic thin films 3 and 4 are formed as a continuous film from the front gap side where the magnetic gap g is provided to the back gap side along the abutting surface shape of the substrates 7 and 8 including the inside. There is.

As the ferromagnetic metal materials used for the metal magnetic thin films 3 and 4, there are used conventionally known ferromagnetic alloy materials having a high saturation magnetic flux density and an excellent soft magnetic property, which are crystalline or amorphous. It doesn't matter. For example, Fe-based alloy, Co-based alloy, Fe-Ni-based alloy, Fe-C-based alloy,
Fe-Al-Si based alloy, Fe-Ga-Si based alloy, F
e-Al-Ge-based alloy, Fe-Ga-Ge-based alloy, Fe
-Si-Ge based alloy, Fe-Co-Si based alloy, Fe-
A crystalline alloy material such as Ru-Ga-Si-based alloy or Fe-Co-Si-Al-based alloy, Co-Zr-Nb, Co-Z
Examples thereof include amorphous alloys such as r-Nb-Ta.
Of course, commonly used amorphous alloys (for example, one or more elements of Fe, Ni, Co and P, C, B, S
An alloy consisting of one or more elements of i, or Al, Be, Sn, In, Mo, W, Ti, M containing this as a main component
Metal-metalloid amorphous alloys such as alloys containing n, Cr, Zr, Hf, Nb, etc., or Co-Zr,
A metal-metal amorphous alloy such as an alloy containing a transition element such as Co—Hf as a main component, or an alloy obtained by adding a rare earth element thereto. ) Etc. can also be used.

In order to further increase the output of the magnetic head and to avoid the eddy current loss in a high band, the metal magnetic thin films 3 and 4 are provided with an insulating film and a number of thin metal layers. Alternatively, a multilayer film structure formed by stacking the layers may be used. In this case, Ta ₂ O ₅ , Al ₂ O ₃ and Zr are used in addition to SiO ₂ which has been used as an insulating film.
A film made of a material such as O ₂ or Si ₃ N ₄ is used.
As a method for forming each metal layer and the insulating film at this time, a vacuum thin film forming technique typified by a vacuum vapor deposition method, a sputtering method, an ion plating method, a cluster ion beam method or the like can be adopted.

In the pair of magnetic core halves 1 and 2 thus formed, the end faces of the metallic magnetic thin films 3 and 4 are butted against each other with a gap film (not shown) interposed therebetween, and They are integrated by being joined by the fused glasses 5 and 6. Therefore, the metal magnetic thin films 3 and 4 facing each other
A magnetic gap g that operates as a recording / reproducing gap is formed therebetween. Track width Tw of this magnetic gap g
Is regulated by the track width regulating grooves 11 and 12 which are formed by cutting out the metal magnetic thin films 3 and 4 provided in the gap portion from both end edges thereof. The fused glasses 5 and 6 filled in the track width regulating grooves 11 and 12 are
It plays a role of ensuring the contact property with the magnetic recording medium.

Here, particularly in the present embodiment, the shapes of the winding grooves 9 and 10 that greatly affect the magnetic characteristics of the metal magnetic thin films 3 and 4 forming the magnetic path will be described below with reference to FIG. One of the winding grooves 9 and 10 provided on each of the substrates 7 and 8 has a substantially V-shaped side surface shape, and the other has a substantially U-shaped side surface shape. That is, these winding grooves 9 and 10 are asymmetrical to each other. The substantially V-shaped winding groove 9 is composed of a pair of side walls 9a and 9b that are inclined in opposite directions with respect to the abutting surface S of the metal magnetic thin films 3 and 4, and these side walls 9a and 9b are used. The shape of the side surface is substantially V-shaped. The winding grooves 9 and 10 have a substantially triangular shape including the abutting surface S of the metal magnetic thin films 3 and 4. On the other hand, the winding groove 10 having a substantially U-shaped side surface has a pair of side walls 10a and 10b inclined in opposite directions with respect to the abutting surface S of the metal magnetic thin films 3 and 4, and the side walls 10a. , 10b, and a coil winding wall 10c that is substantially parallel to the abutting surface S, and the side surface thereof is generally U-shaped. When the winding groove 10 is viewed in a shape including the abutting surface S, the side surface thereof has a substantially trapezoidal shape.

The magnetic properties of the metal magnetic thin films 3 and 4 formed in the winding grooves 9 and 10 are particularly affected.
The metal magnetic thin films 3 and 4 are the portions formed on the side walls 9a and 10a near the magnetic gap. Therefore, in this embodiment, the shapes of the side walls 9a and 10a near the magnetic gap are defined as follows. That is, the side wall 9a of the winding groove 9 having a substantially V-shaped side surface and the metal magnetic thin film 3,
When the angle formed by the abutting surfaces S of the four is α, and the angle between the side wall 10a of the winding groove 10 having a substantially U-shaped side surface and the abutting surface S is β, 5 ° ≤α≤30
And 30 ° ≦ β ≦ 50 °, 50 ° ≦ α + β ≦ 80 °. Further, the core width of the magnetic core half 1 in which the V-shaped winding groove 9 is formed in the magnetic recording medium running direction is L ₁ , and the other magnetic core half 2 is in the magnetic recording medium running direction. If the core width at L is L ₂ , then L ₁ ≤L ₂ .

When the winding grooves 9 and 10 are formed with such a relationship, the magnetic permeability of the metal magnetic thin films 3 and 4 formed on the side walls 9a and 10a near the magnetic gap is increased, and as a result, the magnetic path is formed. The magnetic characteristics of the constituent metal magnetic thin films 3 and 4 are significantly improved. Therefore, the reproduction efficiency is improved, the recording / reproducing can be sufficiently performed on the high coercive force magnetic recording medium, and the magnetic recording / reproducing apparatus aiming at high image quality can be supported. Further, the core width L ₁ of the magnetic core half body 1 in which the winding groove 9 whose side surface is substantially V-shaped is formed is made narrower than the core width L ₂ of the other magnetic core half body 2. Therefore, a double azimuth head in which a pair of magnetic heads are closely arranged to face each other can be easily formed.

By the way, the angles α and β of the side walls 9a and 10a of the winding grooves 9 and 10 in the vicinity of the magnetic gap are regulated to the above values based on the following consideration. Side walls 9a, 10a near the magnetic gap of the winding grooves 9, 10
As shown in FIG. 3, the magnetic permeability of the metal magnetic thin films 3 and 4 formed above tends to deteriorate as the angles α and β increase. Dependent. From this data, it can be seen that the angles α and β of the side walls 9a and 10a have the highest magnetic permeability when they are zero.
When the angle α of the side wall 9a of one winding groove 9 is set to zero, the core volume of the magnetic core half body 1 in which this winding groove 9 is formed increases, and the increase in the inductance is greater than the increase in the reproduction efficiency. However, the efficiency per number of windings (L conversion regeneration efficiency) decreases. Then, when the L-converted reproduction efficiency was obtained using the angle α as a parameter, a value as shown in FIG. 4 was obtained. From this result, when the range that does not affect the recording and reproduction is obtained, the above-mentioned angular range is obtained.

In order to manufacture the magnetic head in which the winding grooves 9 and 10 are asymmetrical as described above, the magnetic head is manufactured according to the following procedure. First, as shown in FIG. 5, a ferrite block substrate 1 cut out in a rectangular shape made of an oxide magnetic material such as Mn—Zn ferrite or Ni—Zn ferrite.
Prepare a pair of 6 and 17.

Next, one ferrite block substrate 16
As shown in FIG. 6, a track width regulation groove 18 for regulating the track width of the magnetic gap is formed in the one main surface 16a which is the abutting surface of. Such track width regulation groove 1
8 are formed as continuous grooves having an arcuate cross-section in the short side direction of the ferrite block substrate 16, and a plurality of them are formed in accordance with the number of magnetic heads to be manufactured with a predetermined pitch in the longitudinal direction of the ferrite block substrate 16. To do.

Then, a winding groove 19 and a glass groove 20 are formed along the longitudinal direction of the ferrite block substrate 16 in a direction orthogonal to the track width regulating groove 18. To form the winding groove 19, as shown in FIG. 7, a cutting process is performed using a rotary grindstone 21 having a substantially V-shaped cutting edge portion. At this time, the angle α between the side wall 19a of the winding groove 19 near the magnetic gap and the one main surface 16a of the ferrite block substrate 16 is 5 ° ≦ α ≦ as described above.
Set to 30 °. On the other hand, the glass groove 20 has a substantially U-shaped cross section.

Similarly, as shown in FIG. 8, a track width regulating groove 22, a winding groove 23, and a glass groove 24 are formed on one main surface 17a which is the abutting surface of the other ferrite block substrate 17. .. Winding groove 23 formed here
Is formed by cutting the cutting edge portion with a rotary grindstone 25 having a substantially trapezoidal shape, as shown in FIG. At this time, the side wall 23a near the magnetic gap of the winding groove 23
The angle β between the main surface 17a of the ferrite block substrate 17 and 30 ° ≦ β ≦ 50 ° is set as described above.

Next, as shown in FIGS. 9 and 10, one main surface 16a of each of the ferrite block substrates 16 and 17,
Fe-A over the entire surface of 17a including each groove.
Ferromagnetic metal materials such as 1-Si alloys and Fe-Ru-Ga-Si alloys are deposited by vacuum thin film forming techniques such as sputtering and vapor deposition to form metal magnetic thin films 26 and 27, respectively. The metal magnetic thin films 26 and 27 are made to have a film thickness of 4 μm to 10 μm.

Next, as shown in FIG. 12, these ferrite block substrates 16 and 17 are connected to each other by the metal magnetic thin film 2 of each other.
6 and 27 are butted against each other while the tracks are aligned. When these ferrite block substrates 16 and 17 are butted, a gap spacer for defining the gap length of the magnetic gap is interposed.

Then, the winding grooves 19 butted against each other,
A round bar of glass is inserted into each of 23 and the glass grooves 20 and 24 to fuse the glass. As a result, the fused glass 28 is filled in the space portion having an elliptical shape sandwiched by the track width regulating grooves 18, 22 facing each other, and the metal magnetic thin films 26 facing each other between the track width regulating grooves 18, 22 are filled. , 27 flows through the fused glass 28. The fused glass 28 flowing between the metal magnetic thin films 26 and 27 operates as a gap film. It should be noted that a gap film made of SiO ₂ or the like is preliminarily attached on the metal magnetic thin film 26 of one of the ferrite block substrates 16 to make it
You may make it join 6 and 17.

Then, the block 29 integrally joined is formed.
Is sliced at the positions of line aa and line bb shown in FIG. As a result, the head chip 30 as shown in FIG. 13 is manufactured. Then, the head chip 30 is cut into a predetermined size to manufacture the magnetic head described above.

[0027]

As is clear from the above description, in the magnetic head of the present invention, the asymmetric winding groove shape is formed so that the magnetic permeability of the metal magnetic thin film formed in the winding groove does not decrease. Therefore, the magnetic permeability of the metal magnetic thin film formed in the winding groove can be significantly improved. Therefore, according to the magnetic head of the present invention, it is possible to sufficiently perform recording / reproducing even on a magnetic recording medium having a higher coercive force due to improved magnetic characteristics and high reproducing efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic head to which the present invention is applied.

FIG. 2 is a sectional view of a magnetic head to which the present invention is applied.

FIG. 3 is a characteristic diagram showing angle dependence of relative magnetic permeability.

FIG. 4 is a characteristic diagram showing the angle dependence of L conversion regeneration efficiency.

FIG. 5 is a perspective view showing a step of producing a ferrite block substrate, which sequentially shows steps of producing a magnetic head to which the present invention is applied.

FIG. 6 is a perspective view sequentially showing steps of manufacturing a magnetic head to which the present invention is applied, showing steps of forming winding grooves and the like on one ferrite block substrate.

FIG. 7 is a side view of a step of forming a winding groove on one ferrite block substrate, which sequentially shows steps of manufacturing a magnetic head to which the present invention is applied.

FIG. 8 is a perspective view sequentially showing steps of manufacturing a magnetic head to which the present invention is applied, showing steps of forming winding grooves and the like on the other ferrite block substrate.

FIG. 9 is a side view showing a sequence of steps of producing a magnetic head to which the present invention is applied, and a step of forming a winding groove on the other ferrite block substrate.

FIG. 10 is a perspective view sequentially showing steps of manufacturing a magnetic head to which the present invention is applied, showing steps of forming a metal magnetic thin film on one ferrite block substrate.

FIG. 11 is a perspective view sequentially showing steps of manufacturing a magnetic head to which the present invention is applied, showing steps of forming a metal magnetic thin film on the other ferrite block substrate.

FIG. 12 is a perspective view showing a step of manufacturing a magnetic head to which the present invention is applied in sequence, showing a step of joining ferrite block substrates.

FIG. 13 is a perspective view of a head chip cut out in a slicing step, which sequentially shows steps of manufacturing a magnetic head to which the present invention is applied.

FIG. 14 is a sectional view of a conventional magnetic head.

[Explanation of symbols]

 1, 2 ... Magnetic core half 3, 4 ... Metal magnetic thin film 5, 6 ... Fused glass 7, 8 ... Substrate 9, 10 ... Winding groove 11, 12 ... Track width regulation groove

Claims (1)

[Claims] 1. A pair of magnetic core halves each comprising a substrate made of an oxide magnetic material having a winding groove formed therein and a metal magnetic thin film formed along the abutting surface of the substrate including the inside of the winding groove. In a magnetic head having a closed magnetic circuit formed by abutting metal magnetic thin films on each other, the winding grooves formed in the pair of magnetic core halves are asymmetrical in shape. Magnetic head.