JPH0689407A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To improve mass productivity by superposing a pair of laminated cores, which are formed by notching only the one surface at magnetic gap ends to allow a track width to remain, on each other in the track width part via a gap material, thereby forming the prescribed track width. CONSTITUTION:Only a part of the gap surface 21 is worked to have notched grooves and thereafter, a nonmagnetic material, such as glass, is packed into the notched grooves and the gap surface is finished smooth. A winding groove 10 is then worked in a laminated block 20 to form a laminated block 20a. The laminated block 20a and the laminated block 20b subjected to the same working are superposed on each other via the gap material 6 of the thickness corresponding to a gap length and these blocks are heated, thereby, the low melting glass within the notched grooves 15 is partly remelted. The surface blocks are thus joined and the head is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal-based laminated magnetic head suitable for recording and reproducing high frequency signals and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, a magnetic recording / reproducing apparatus for recording / reproducing a high frequency signal such as a VTR has been increased in density. As a means therefor, there is a method of shifting a recording signal to a high frequency band or a method of narrowing a track width. As a result of using the high coercive force medium in order to improve the performance in the high frequency band, a metal-based magnetic material having a high magnetic flux density characteristic such as amorphous or sendust is used in the core of the magnetic head. In general, a metal-based magnetic material has a low specific resistance, and thus has a drawback that eddy current loss occurs in a high frequency band and magnetic characteristics deteriorate.

As a countermeasure, a laminated structure is widely used in which a metal magnetic material is thinned by a method such as sputtering or vapor deposition without using a bulk material and is laminated via an insulating layer to form a predetermined track.

A conventional laminated magnetic head will be described below. FIG. 9 shows an example of the magnetic head. The magnetic alloy thin film 2 and the electrically and magnetically insulating thin film 3 are alternately laminated between the auxiliary substrates 1a and 1b until a predetermined track width is obtained to form a laminated core half 4, and a similar laminated core 5 is formed as a gap. The material 6 is sandwiched between the magnetic heads. Reference numeral 7 is glass for joining the laminated cores 4 and 5. Also, FIG.
Reference numeral 0 is a combination type magnetic head often used in recent VTRs, in which two head cores having different track widths and gap inclination angles are bonded on a base 9 at a constant gap interval 8. Normally, since the gap spacing 8 is narrow and if 620μm when 740Myuemu, PAL system NTSC system, is it not possible to apply directly bond the head core as shown in FIG. 9, a ₁ the head core 4 as shown in FIG. 9, It is necessary to use a core cut at the cutting line of a ₂ .

[0005]

As described above, in the above conventional structure, since the thickness of the entire magnetic path of the core is the same as the track width, the magnetic field is reduced when the track width is reduced for high density recording. There is a problem that the width of the laminated layer, which is a path, is also narrowed, the magnetic resistance of the core increases, and the reproduction efficiency decreases.
Further, in order to obtain a combination type head as shown in FIG.
By cutting the core 4 along the cutting lines a ₁ and a ₂ as described above, the cross-sectional area 10 of the core 4 becomes as small as the cross-sectional area 11. When the thickness of the magnetic alloy film becomes thin due to the narrow track width, the cross-sectional area 1
1 also becomes smaller and the magnetic resistance of the core 4 further increases, which causes the reproduction efficiency of the head to be significantly reduced.
This is one of the important issues of the laminated type magnetic head in order to meet the demands of the circuit that require higher reproduction output in a narrow track width.

The present invention solves the above-mentioned conventional problems. Even if the track width becomes narrow, the magnetic flux is effectively linked to the coil without lowering the magnetic resistance of the magnetic circuit of the core, thereby improving the reproduction efficiency. An object is to provide a high output head without lowering.

[0007]

To achieve this object, the present invention provides a pair of magnetic alloy film laminated core halves each having a magnetic alloy thin film and an insulating film alternately laminated between auxiliary substrates. In a magnetic head in which the gap width is abutted and the abutting width is the track width, the magnetic alloy thin film and the insulating film whose thickness per layer is T ₁ are alternately stacked to have a thickness T ₂ wider than the track width T _3. The first step of sandwiching the magnetic alloy film between the auxiliary substrates to form a laminated core half body, and notching the end face of at least one of the gap surfaces of the magnetic alloy film of the laminated core with a remaining length of the gap surface. After processing so that the gap becomes almost equal to the track width, a second step of polishing the gap surface smoothly and forming a gap material of a non-magnetic material such as an oxide on the gap surface of the laminated core and butting them together It has a configuration comprising a third step of occupying dressed glass melt in the notches of the magnetic alloy layer with the butt length and track width.

[0008]

With this structure, the magnetic alloy film wider than the track is used as the magnetic path, so that the reduction of the reproducing efficiency can be minimized even in the narrow track width head.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of the head as seen from the tape contact surface side. In the figure, a magnetic alloy thin film 2 such as amorphous or sendust and an insulating thin film 3 are alternately laminated between auxiliary substrates 1a and 1b, which are non-magnetic materials such as ceramics and glass, by a sputtering technique, a vapor deposition technique, etc. A magnetic alloy film 12 of T ₂ is formed to form a half 13a of the laminated core. A notch groove 15 is formed on one end surface of the magnetic alloy film 12 leaving a gap surface length substantially equal to the track width 14. The same laminated core 13b is a head in which the gap surface of the magnetic alloy film 12 is abutted via the gap material 6 to have a track width 14. Winding 16 is laminated core 1
3a or the laminated core 13b is wound around a winding window 17 provided at the center of one or both of them. 18
Is a base for attaching these heads to the VTR main body. An embodiment of the magnetic head manufacturing method of the present invention will be described with reference to FIG. FIG. 2 shows a magnetic alloy film having a thickness wider than the track width, which is obtained by alternately laminating a magnetic alloy thin film 2 such as amorphous or sendust and an insulating thin film 3 such as SiO ₂ on the auxiliary substrate 1a by a thin film forming method such as a sputtering technique or a vapor deposition technique. Form 12 to make a laminated core. Generally magnetic alloy thin film 2
Is determined by the skin depth at which magnetic flux flows when eddy currents are generated at the frequency used. As a guideline for the film thickness per layer of the laminated film 2, considering the thickness twice the skin depth, the upper limit of the frequency band is 10 MHz, and when the magnetic permeability is 2000, the skin depth is about 4 μm. As 8
It is better to set the thickness to about μm or less. In the case of the SVHS head, the track width is 50 μm in the NTSC standard mode head and is in the vicinity of 25 to 30 μm in the triple mode, but in order to make the film thickness of each layer uniform, the track width is an integral multiple of the film thickness per layer. It decides and is laminated. The magnetic alloy film 12 laminated to a predetermined thickness by a sputtering technique or the like is bonded to the auxiliary substrate 1b by a bonding material 19.
When the magnetic alloy thin film 2 is amorphous, a low melting point glass having a melting point lower than the crystallization temperature of amorphous is used as the bonding material 19. FIG. 3 shows a laminated block 20 in which a plurality of auxiliary substrates 1a and 1b and a magnetic alloy film 12 are arranged in consideration of production efficiency. In FIG. 4, the gap surface 21, the sliding surface 22, and a part of at least one side of the magnetic alloy film 12 are processed together with the auxiliary substrate to form the notch groove 15 to regulate the track width.
FIG. 5 shows a case where the notch groove is formed only on a part of the gap surface 21, and the same effect as that of FIG. 4 is obtained. Then, a non-magnetic material such as glass is filled in the notch groove to finish the gap surface smooth. FIG. 6 shows a bonding state. The laminated block 20 shown in FIG. 5 is processed into the laminated groove 20a by processing the winding groove 10, and the laminated block 20b subjected to the same processing as the laminated block 20a is superposed via the gap material 6 having a thickness corresponding to the gap length. By heating, a part of the low melting point glass in the notch groove 15 is melted again, and both blocks are joined to form a head. FIG. 7 shows the laminated block joined at the gap surface as seen from the tape contact surface 22.

The magnetic alloy film 12 is inclined by an angle α with respect to the perpendicular 23 of the gap surface. Further, the notch groove for controlling the track width is processed at an angle β with respect to the gap surface 25 so that the processed surface 24 does not act as a pseudo gap, so that a signal from an adjacent or adjacent track is rarely reproduced. Become. At this time, α and β have the following relational expressions. b ₁ and b ₂ are cutting lines, which are cut into each core and then adhered to the base 18 as shown in FIG. 1, and then the tape sliding surface is polished to form a head.

FIG. 11 shows the effect of improving the reproduction efficiency according to the present embodiment described with reference to FIG. 1 in comparison with the conventional example. The head has a track width of 20 μm and a magnetic alloy film thickness of 2
The regeneration efficiency when changing from 0 to 80 μm is required. The amount of change is expressed in dB based on the thickness of the magnetic alloy film of 20 μm, that is, the conventional example. As is clear from FIG. 11, by forming the core with a magnetic alloy film wider than the track width, the magnetic resistance of the core is lowered and the reproduction efficiency is improved. According to the present embodiment, the thickness of the magnetic alloy film is set to 50 μm, which is almost the same as the track width in the standard mode, so that the thickness is about 4 dB.
Can be improved.

[0013]

[Equation 2]

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. FIG. 8 is a second embodiment of the present invention as seen from the tape sliding surface 22 of the laminated block 20.

The difference from the configuration of FIG.
The point is that a laminated block 20c in which the thickness of a magnetic alloy film of the same type as the conventional one is made the same as the track width is used for b.

If the core 20a of the present invention is used on the side of the core 4 of FIG. 9 when the combination head is manufactured as shown in FIG. 10 described above, the core cross section is narrowed by cutting along the cutting lines a ₁ and a _2. Even so, since the magnetic alloy film is thick, the increase in magnetic resistance is smaller than that of the conventional product.

[0017]

As described above, according to the present invention, since the magnetic alloy thin film and the insulating thin film are laminated to form the laminated core of the magnetic alloy film, the head having a small eddy current loss even in the high frequency band can be obtained. In addition, the laminated core is taken wide and the notch processing is put in,
Since the magnetic flux in the track portion is narrowed down, the magnetic resistance of the magnetic path is small even when the track width is narrow. Further, since the notch is processed only on one side of the magnetic alloy film of the laminated core, the other is held by the auxiliary substrate, and even a magnetic alloy film that is easily subjected to processing strain can be processed without being subjected to excessive strain. It is possible to realize a high-performance head having excellent properties.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic head according to a first embodiment of the invention.

FIG. 2 is a structural diagram of a magnetic alloy film in the first embodiment.

FIG. 3 is a perspective view of a laminated block according to the first embodiment.

FIG. 4 is a cutaway perspective view of a laminated block according to the first embodiment.

FIG. 5 is a cutaway perspective view of a laminated block according to the first embodiment.

FIG. 6 is a perspective view of a laminated block according to the first embodiment.

FIG. 7 is a front view of a laminated block according to the first embodiment.

FIG. 8 is a front view of a laminated block according to a second embodiment.

FIG. 9 is a front view and a side view of a core of a conventional laminated type magnetic head.

FIG. 10 is a plan view of a conventional combination type magnetic head.

FIG. 11 is a graph showing the effect of improving the regeneration efficiency according to the first embodiment.

[Explanation of symbols]

 1a, 1b Auxiliary substrate 2 Magnetic alloy thin film 3 Insulating thin film 6 Gap material 12 Magnetic alloy film 13a, 13b Laminated core 14 Track width 15 Notch groove 16 Winding 17 Winding window 18 Base 19 Binder

Claims (4)

[Claims] 1. A pair of laminated cores of a magnetic alloy film in which a magnetic alloy thin film and an insulating thin film are alternately multilayered between auxiliary substrates are overlapped with a gap made of a nonmagnetic material interposed therebetween, and the overlapping width is taken as a track width. In the magnetic head, when the film thickness per _one layer of the magnetic alloy thin film is T ₁ , the total film thickness when multilayered is T ₂ , and the track width is T ₃ , the multilayered wide film having the following general formula is given. After a laminated core is formed from the magnetic alloy film of, a pair of laminated cores, which are notched only on one side of the magnetic gap edge with the track width left, are stacked at the track width portion via a gap material to form a predetermined track width. A magnetic head characterized in that [Equation 1] 2. When regulating at least one of the magnetic gaps of the magnetic film by notching and leaving a track width and controlling the track width, the angle of the processed surface is at least 2 of the gap inclination angle on the tape pattern with respect to the gap surface. 2. The magnetic head according to claim 1, wherein the magnetic head is doubled or more. 3. A magnetic head in which a pair of half pairs of the laminated core, each of which has a cutout having a track width formed at one end of a magnetic gap, is joined through a gap material, wherein the cutout has a center line of the track. A magnetic head characterized in that the magnetic heads are arranged on opposite sides of each other. 4. A first step of forming a laminated core half body having a core thickness thicker than a predetermined track width with a magnetic alloy film laminated between auxiliary substrates with an insulating film interposed between the auxiliary substrate and at least one of the laminated core halves. A second step of notching so that the length of the gap surface of the laminated core half is approximately equal to the track width, and smoothing and polishing the gap forming surface; and laminating both of them by interposing an oxide non-magnetic material on the gap forming surface. The core half bodies are butted against each other at the gap surface to form a predetermined track width, and glass is fused to the cut-out processed portion of the magnetic alloy film.
A method of manufacturing a magnetic head, comprising the steps of: