JPH1064008A - Magnetic head - Google Patents

Abstract

(57) [Problem] To provide a magnetic head having high head efficiency while realizing good contact characteristics with a recording medium. A magnetic head (1) has a pair of magnetic head halves (2a, 2b) formed on a non-magnetic substrate and having a magnetic layer functioning as a magnetic core (4) joined thereto via a magnetic gap (g). Notches 9 are formed on both sides of the recording medium sliding surface 8 in a direction substantially parallel to the recording medium sliding direction, and are perpendicular to the depth direction of the magnetic gap g.
The distance between the imaginary plane S in contact with the recording medium and the surface of the notch 9 facing the recording medium, that is, the sliding width processing bottom surface 9 is closer to both ends in the recording medium sliding direction than the distance t ₁ near the magnetic gap. Write interval t ₂ of is larger.

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 cassette recorder, and more particularly, to a magnetic head having a sliding surface formed on a sliding surface of a recording medium.

[0002]

2. Description of the Related Art A magnetic head must exhibit good electromagnetic conversion characteristics in a higher frequency band in order to cope with a higher density of a magnetic recording medium and digitization of an information signal. Requested.

Conventionally, magnetic heads used in video cassette recorders and the like include a metal-in-gap (MIG) magnetic head in which a metal film is formed on a magnetic gap forming surface of a magnetic core made of ferrite, and a non-magnetic head. A laminated magnetic head having a magnetic layer sandwiched between magnetic ceramic substrates has been put to practical use.

However, the MIG type magnetic head has a large impedance and is not suitable for use in a high frequency band. On the other hand, in the stacked magnetic head, it is necessary to reduce the thickness dimension of the magnetic layer constituting the magnetic path with the decrease in the track width due to the high-density recording.
The head efficiency is reduced.

Therefore, a magnetic head having high head efficiency in a high frequency band has a magnetic path which is shortened by forming a magnetic layer functioning as a magnetic core on a non-magnetic substrate, and a magnetic gap forming surface is formed by a thin film forming process. A magnetic head having a thin film coil has been proposed.

In this magnetic head 100, as shown in FIG. 14, in order to obtain good contact characteristics between the recording medium sliding surface 101 and the recording medium, the recording medium sliding surface 101 is processed by sliding. The width T is controlled. That is,
Notch portions 102 are formed at both ends of the recording medium sliding surface 101, whereby the sliding width T, which is the width of the portion where the recording medium sliding surface 101 contacts the recording medium, is regulated.

In the magnetic head 100, the surface of the notch 102 facing the recording medium, that is, the sliding width processing bottom surface 103, is similar to the MIG type magnetic head or the like in the depth direction of the magnetic gap g. It is formed linearly so as to be substantially orthogonal. The notch 102 formed to regulate the sliding width T in this way is
The purpose of the present invention is to obtain good contact characteristics between the recording medium and the recording medium.
Need to be deep enough to obtain

[0008]

By the way, in the above-described magnetic head 100, a magnetic layer is formed on a part of the inclined surface formed on the non-magnetic substrate, and a magnetic path is constituted only by the magnetic layer. . Then, a part of the magnetic layer is cut out by a notch 102 for regulating the sliding width T.
Therefore, when the processing depth of the notch 102 is large, the volume of the magnetic core 104 formed by the magnetic layer becomes small, and the head efficiency is reduced.

The magnetic head 100 has a recording medium sliding surface 101 having a smaller radius of curvature as the drum diameter of the mounted drum is reduced.
It is necessary to increase the distance between the bottom surface 01 and the sliding width processing bottom surface 103. In the magnetic head 100, when the distance between the recording medium sliding surface 101 and the sliding width processing bottom surface 103 increases, the volume of the magnetic core 104 further decreases, and the head efficiency of the magnetic head 100 further decreases.

[0010] Such a tendency becomes more remarkable as the thickness of the magnetic layer becomes thinner as the track width decreases due to the higher recording density of the recording medium.

Accordingly, the present invention has been proposed in view of the above situation, and has a sliding width processing bottom surface 10 formed by a recording medium sliding surface 101 and a notch 102.
An object of the present invention is to provide a magnetic head having high reproduction efficiency while realizing good contact characteristics with a recording medium by controlling an interval with the recording medium.

[0012]

According to the present invention, there is provided a magnetic head comprising a pair of magnetic head halves each having a magnetic layer formed on a non-magnetic substrate and functioning as a magnetic core. A magnetic head which is joined through a magnetic gap and has cutouts formed on both sides of a recording medium sliding surface in a direction substantially parallel to the recording medium sliding direction, the magnetic head being orthogonal to the depth direction of the magnetic gap. The gap between the virtual plane that is in contact with the recording medium sliding surface and the surface of the notch facing the recording medium is formed to be larger on both sides near both ends in the recording medium sliding direction than on the side near the magnetic gap. I do.

In this magnetic head, the distance between the imaginary plane and the sliding width processing bottom surface facing the recording medium in the notch is closer to both ends in the sliding direction of the recording medium than to the vicinity of the magnetic gap. Is large, it is possible to increase the volume of the magnetic layer functioning as a magnetic core while maintaining good contact characteristics with the recording medium, and to improve the head efficiency.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a magnetic head and a method of manufacturing the same according to the present invention will be described in detail with reference to the drawings. In this embodiment, the present invention is applied to a magnetic head for a video cassette recorder.

As shown in FIGS. 1 and 2, the magnetic head 1 according to the present embodiment has a pair of magnetic head halves 2a and 2b abutted through a magnetic gap g to be joined and integrated. The magnetic head 1 includes a pair of magnetic head halves 2.
A metal film made of Au or the like formed on the surfaces of a and 2b is bonded by forming a magnetic gap g by metal diffusion bonding.

The magnetic head halves 2 a and 2 b are composed of a substrate 3, a magnetic layer 4 formed on the substrate 3 and functioning as a magnetic core, and a glass 5 filled on the substrate 3 and the magnetic layer 4. And a thin film coil 6 formed on the glass 5 by a thin film forming process, and a terminal groove 7 for electrically connecting the thin film coil 6 to an external terminal. And a pair of magnetic head halves 2a, 2b
Are joined so that the respective magnetic layers 4 abut each other to form a front gap fg and a back gap bg between the respective magnetic layers 4. The magnetic head 1 is subjected to a sliding width process in order to control a sliding width T of the recording medium sliding surface 8.

As shown in FIG. 1 (a), the magnetic head 1 is provided with cutouts on both sides of the recording medium sliding surface 8 which are substantially parallel to the recording medium sliding direction by performing the sliding width processing. 9
The sliding width T is set to a predetermined width by the notch 9. The magnetic head 1 is formed so that the radius of curvature of the recording medium sliding surface 8 and the radius of curvature of the notch 9 facing the recording medium, that is, the radius of curvature of the sliding width processing bottom surface 10 are substantially the same.

Therefore, the magnetic head 1 is shown in FIG.
As shown in (b), in the vicinity of the magnetic gap g, the interval between the virtual plane S perpendicular to the depth direction and in contact with the recording medium sliding surface 8 and the sliding width processing bottom surface 10 is t ₁ , and the notch is notched. In the vicinity of both ends of the portion 9, t ₁ <t ₂ , where t ₂ is the distance between the virtual plane S perpendicular to the depth direction and in contact with the recording medium sliding surface 8 and the sliding width processing bottom surface 10. It is formed as follows. The magnetic head 1 is formed such that the interval t between the recording medium sliding surface 8 and the sliding width processing bottom surface 10 is substantially constant from the vicinity of the magnetic gap g to the vicinity of both ends of the notch 9. ing.

In this embodiment, the magnetic head 1
Is formed so that t ₁ is about 10 μm, and the radius of curvature of the sliding width processed bottom face 10 and the radius of curvature of the recording medium sliding face 8 are both about 3 μm.
mm.

That is, in the magnetic head 1, the distance between the virtual plane S near the magnetic gap g and the sliding width processing bottom surface 10 is t _1, and the virtual plane S near the both ends of the notch 9 and the sliding width processing bottom surface are set. It is formed such that t ₁ <t ₂ when the interval from the reference numeral 10 is t ₂ . In the magnetic head 1, the recording medium sliding surface 8 and the sliding width processed bottom surface 10 are formed.
Are formed with substantially the same radius of curvature, it is possible to obtain good hitting characteristics with respect to the recording medium, and it is possible to increase the volume of the magnetic layer 4 functioning as a magnetic core, It is possible to improve head efficiency.

In the magnetic head 1, the distance between the virtual plane S and the sliding width processing bottom surface 10 in the depth direction is
Notch 9 than the interval t ₁ near the magnetic gap
As shown in FIG. 3, if the distance t ₂ in the vicinity of both ends is large, the sliding width processed bottom surface 10 may be formed in a trapezoidal shape. Further, the magnetic head 1 is formed so that the sliding width processing bottom surface 10 is formed in a polygonal shape, and the distance between the virtual plane S and the sliding width processing bottom surface 10 increases toward both ends of the notch 9. You may.

In the magnetic head 1 configured as described above, the sliding width processing bottom surface 10 is formed with a small distance from the virtual plane S in the vicinity of the magnetic gap, and is near both ends in the recording medium sliding direction. In this case, the distance between the magnetic layer 4 and the virtual plane S is increased, so that it is possible to obtain good hitting characteristics with respect to the recording medium and increase the volume of the magnetic layer 4 functioning as a magnetic core. Yes, it is possible to improve the head efficiency.

[0023] Incidentally, the magnetic head 1, the distance between the virtual plane S and the slide width processing bottom 10 in the vicinity of the magnetic gap and t _1, a virtual plane S and the sliding width processing in the vicinity of both ends of the recording medium sliding direction If the distance from the bottom surface 10 is t ₂ , the radius of curvature of the sliding width processed bottom surface 10 is set smaller than the radius of curvature of the recording medium sliding surface 8 if t ₁ <t _2. May be formed.

Hereinafter, the detailed configuration of the magnetic head 1 will be described through the method of manufacturing the magnetic head 1 described above.

When manufacturing the magnetic head 1, first, FIG.
As shown in FIG. 2, a flat substrate 3 made of a nonmagnetic material such as a MnO-NiO mixed binder is formed into a length of about 30 mm, a width of about 30 mm, and a thickness of about 2 mm.

Next, as shown in FIG. 5, a plurality of magnetic core grooves 3a for forming magnetic cores on the substrate 3 are formed on the substrate 3 by a grindstone having one surface formed at 45 degrees so that the inclined surface has an inclination of about 45 degrees. They are formed at equal intervals and in parallel. here,
The inclination of the slope of the magnetic core groove 3a is not limited to 45 degrees. However, considering the pseudo gap generated in the completed magnetic head 1 and the track width accuracy, about 45 degrees is preferable. In the present embodiment, the magnetic core groove 3a is formed to have a depth of about 130 μm and a width of about 150 μm.

Next, a magnetic layer 4 is formed on the substrate 3 on which the magnetic core groove 3a is formed, as shown in FIG.
The magnetic layer 4 has a sendust (Fe-A
a metal magnetic film made of (1-Si alloy) and a film thickness of about 0.15
An insulating film made of Al ₂ O _{3 having a} thickness of μm is alternately laminated so that three metallic magnetic films are formed.

The structure of the magnetic layer 4 may be a single metal magnetic film, but it is necessary to reduce the thickness of the metal magnetic film in order to reduce eddy current loss and provide high sensitivity in a high frequency band. . Further, the thickness of the insulating film is required to be at least such that an insulating effect can be obtained, but it is necessary to make it sufficiently thin so that the effective track width does not decrease.

The magnetic layer 4 is preferably formed by sputtering, but is preferably formed by vapor deposition, molecular epitaxy (MB), or the like.
A physical film forming method other than the sputtering method such as the E) method or a chemical film forming method may be used.

As a material for the metal magnetic film, Sendust is suitable, but other metal magnetic materials, for example, alloys similar to Sendust, nitrided soft magnetic alloys, carbonized soft magnetic alloys, etc. can also be used. It is. As a material of the insulating film, Al ₂ O ₃ , SiO ₂ , or SiO can be used, and a mixed state of these Al ₂ O ₃ , SiO ₂ , and SiO can also be used.

Next, the substrate 3 on which the magnetic layer 4 has been formed
As shown in FIG. 7, a winding groove 3b for forming the thin film coil 6 and a separation groove 3c for separating the magnetic layer 4 for each magnetic core are perpendicular to the magnetic core groove 3a. It is formed.

As shown in FIG. 2, the winding groove 3b is formed so that the magnetic layer 4 on the front gap side is obliquely narrowed down toward the front gap fg. The fg side is formed with a grindstone having a slope of about 45 degrees. Thus, the front gap f
When the g-side magnetic layer 4 is narrowed toward the front gap fg, the magnetic flux is concentrated and high recording sensitivity is obtained.

However, if the shape of the winding groove 3b is such that the magnetic layer 4 on the front gap fg side is narrowed down toward the front gap fg, the angle of the slope of the winding groove 3b on the front gap fg side is obtained. May not be 45 degrees.
Further, the shape of the winding groove 3b on the front gap fg side may be an arc or a polygon.

The depth of the winding groove 3b may be any depth as long as the magnetic layer 4 is not divided. However, if it is too deep, the magnetic path length increases, and the efficiency of magnetic flux transmission decreases. The width of the winding groove 3b is determined by the width and the number of windings of the thin film coil 6 formed in a later step. In the present embodiment, the line width of the winding groove 3b is about 140 μm,
The depth of b was about 20 μm.

On the other hand, the separation groove 3c may have any shape as long as the magnetic layer 4 is divided, for example, a rectangular shape which is easy to process. The separation groove 3c was formed to a depth of about 150 μm from the bottom of the magnetic core groove 3a. The width of the separation groove 3c defines the length of the magnetic layer 4 on the front gap fg side and the length of the magnetic layer 4 on the back gap bg side. Therefore, the width of the separation groove 3c is determined by a desired balance between the length of the front gap fg of the magnetic head 1 and the length of the back gap bg. However, since the length of the front gap fg is set to wrap the sliding surface 8 of the recording medium when the magnetic head 1 is finally processed into a predetermined shape, the desired front gap fg
The separation groove 3c is formed to be longer than the length. Therefore, in the present embodiment, the separation groove 3c is formed such that the length of the front gap fg is about 300 μm and the length of the back gap bg is about 85 μm.

Next, as shown in FIG.
a, the winding groove 3b and the separation groove 3c are melt-filled with glass 5 having a low melting point.

Next, as shown in FIG. 9, the terminal groove 12 is formed on the substrate 3 so as to overlap with one end of the lead portion of the thin film coil 6. In the present embodiment, the terminal groove 12 is formed to have a width and a depth of about 100 μm.
The cross-sectional shape of the terminal groove 12 is rectangular, polygonal,
Alternatively, the bottom of the terminal groove 12 may be formed to have a round bottom.

Next, as shown in FIG. 10, a good conductive material such as Cu is filled into the terminal groove 12 by a method of pouring a conductive paste or an electrolytic plating method. The surface is flattened by polishing.

Next, as shown in FIG. 11, a spiral thin film coil 6 is formed for each magnetic core in the glass 5 so as to pass through the winding groove 3b by a thin film forming process. In forming the thin film coil 6, first, a concave portion of about 5 μm is formed in a portion where the thin film coil 6 is installed. afterwards,
After patterning the shape of the thin-film coil 6 with a resist, about 3 μm of Cu or the like is formed by electrolytic plating or the like. Here, the thin film coil 6 is formed such that the end thereof contacts the terminal groove 12. In the present embodiment,
Although the coil pattern of the thin film coil 6 is grown by the electrolytic plating method, the present invention is not limited to the electrolytic plating method, but may be a sputtering method, a vapor deposition method, or the like.

Next, each magnetic head half 2 is placed on the substrate 3.
In order to join a and 2b, the joining portion is patterned with an Au thin film.

Next, the substrate 3 is divided in parallel with each terminal groove 12 to produce each magnetic head block half. Thereafter, as shown in FIGS. 12 and 13, the Au thin films formed on the respective magnetic head block halves are brought into contact with each other so as to be in contact with each other, and are subjected to metal diffusion bonding while applying a load to form a magnetic head block. In this embodiment, the magnetic head block halves are joined by metal diffusion bonding, but may be joined by a chemical joining method such as an adhesive.

Next, a sliding width processing is performed in the direction of the recording medium sliding surface of the magnetic head block. In this sliding width processing, a notch 9 is formed to form a sliding width processing bottom surface 10 and the recording medium sliding surface 8 is formed to have a predetermined sliding width T.

In this sliding width processing, the radius of curvature is, for example, about 3 mm to form the recording medium sliding surface 8, and the radius of curvature of the sliding width processing bottom face 10 is about 3 mm to form the notch 9. In this manner, the sliding width processing is performed so that the distance t between the recording medium sliding surface 8 and the sliding width processed bottom surface 10 is substantially the same over the entire cutout 9. In the present embodiment, the distance t between the recording medium sliding surface 8 and the sliding width processed bottom surface 10 is formed to be about 10 μm.

The processing of the sliding width is performed by the distance t between the virtual plane S and the bottom surface 10 of the sliding surface in the vicinity of the magnetic gap.
May be formed so that the radius of curvature of the sliding width processed bottom surface 10 is smaller than the radius of curvature of the recording medium sliding surface 8.

Further, the sliding width processing, as the interval between the virtual plane S and the slide width processing bottom 10, interval t ₂ at both ends of the notches 9 than the interval t ₁ in the vicinity of the magnetic gap becomes larger For example, the sliding width processing bottom face 10 may be formed in a trapezoidal or polygonal shape, and the virtual plane S and the sliding width processing may be formed from the vicinity of the magnetic gap g to both ends of the notch 9. It may be formed so that the interval t with the bottom surface 10 is increased.

Thereafter, the magnetic head block is sliced for each magnetic core and cut out.
Each head chip is manufactured.

By subjecting these head chips to predetermined post-processing, the magnetic head is completed.

The magnetic head 1 will not function as a magnetic head if the sliding surface 8 of the recording medium is worn due to contact with the recording medium and the magnetic gap g is eliminated. The life of such a magnetic head is usually
This is determined by the gap depth, and the longer the gap depth, the longer the life.

However, if the distance t ₁ between the virtual plane S near the magnetic gap and the sliding width processing bottom surface 10 is smaller than the gap depth, when the wear reaches the sliding width processing bottom surface 10, the recording medium is The width of contact with the magnetic head is not properly regulated, and cannot be used as a magnetic head. Therefore, in consideration of the life due to abrasion, it is preferable that the interval t ₁ between the virtual plane S and the sliding width processing bottom surface 10 in the vicinity of the magnetic gap is substantially equal to the gap depth.

However, when the magnetic head 1 is mounted on a rotating drum, the life of the magnetic head may be determined not by the gap depth but by the amount of protrusion from the rotating drum. That is, even if the gap depth is formed sufficiently deep, if the portion protruding from the rotating drum is worn, it cannot be used as a magnetic head. In such a case, the interval t ₁ between the virtual plane S and the sliding width processing bottom surface 10 in the vicinity of the magnetic gap should not be approximately equal to the gap depth but approximately equal to the amount of protrusion from the rotary drum. preferable. This allows
It is possible to increase the volume of the magnetic core without shortening the life of the magnetic head by the processing of the sliding width.

The gap depth is set to about 10 μm,
The distance t ₁ between the virtual plane S and the sliding width processing bottom surface 10 in the vicinity of the magnetic gap is set to about 10 μm, and the recording medium sliding surface 8
And a magnetic head that has been subjected to sliding width processing with the radius of curvature of the sliding width processed bottom surface 10 being 3 mm and the sliding width T of the recording medium sliding surface 8 being 40 μm, and the virtual plane S and the sliding width processed bottom surface. The reproduction output was compared with that of a magnetic head formed by conventional sliding width processing in which the interval was set to about 50 μm and the sliding width processing bottom face was formed linearly. At this time, when the relative speed between the recording medium sliding surface 8 and the metal-deposited tape as the recording medium was set to 10.2 m / s using a drum tester, the magnetic head 1 according to the present embodiment showed the conventional sliding. A reproduction output higher by about 1.5 dB than that of the magnetic head formed by the width processing was obtained.

[0052]

As described in detail above, the magnetic head according to the present invention has a plane perpendicular to the depth direction of the magnetic gap and in contact with the recording medium sliding surface, and a surface of the notch facing the recording medium. Are formed to be larger on both sides near both ends in the recording medium sliding direction than on the side near the magnetic gap.

The magnetic head thus configured can obtain good hitting characteristics with respect to a recording medium, can increase the volume of a magnetic layer functioning as a magnetic core, and can improve head efficiency. It is possible to improve.

[Brief description of the drawings]

FIG. 1 shows a configuration example of a magnetic head according to the present invention,
(a) is a perspective view, (b) is a main part plan view.

FIG. 2 is an enlarged perspective view of a main part showing the vicinity of a magnetic gap of the magnetic head.

FIG. 3 is a plan view of a main part showing a configuration example of a magnetic head.

FIG. 4 is a perspective view showing a substrate.

FIG. 5 is a perspective view showing a state where a magnetic core groove is formed in a substrate.

FIG. 6 is a perspective view showing a state in which a magnetic layer is formed on a substrate on which a magnetic core groove is formed.

FIG. 7 is a perspective view showing a state in which a winding groove and a separation groove are formed on a substrate.

FIG. 8 is a perspective view showing a state where glass is filled on a substrate.

FIG. 9 is a perspective view showing a state in which terminal grooves are formed on glass filled on a substrate.

FIG. 10 is a perspective view showing a state where a conductive material is filled in a terminal groove formed on a substrate.

FIG. 11 is a perspective view showing a state where a thin film coil is formed.

FIG. 12 is a perspective view showing a state in which the substrate is cut in parallel with the terminal grooves and a pair of magnetic head block halves are joined.

FIG. 13 is a perspective view showing a state where a pair of magnetic head block halves are joined.

FIG. 14 is a perspective view showing a conventional magnetic head.

[Explanation of symbols]

1 magnetic head, 2 magnetic head halves, 3 substrates, 4
Magnetic layer, 6 Thin film coil, 5 Magnetic layer, 8 Recording medium sliding surface, 9 Notch, 10 Sliding width processed bottom

Claims (3)

[Claims] A pair of magnetic head halves each having a magnetic layer formed on a non-magnetic substrate and functioning as a magnetic core are joined via a magnetic gap, and recording is performed on both sides of a recording medium sliding surface. In a magnetic head having a notch portion substantially parallel to a medium sliding direction, a virtual plane orthogonal to a depth direction of a magnetic gap and in contact with a recording medium sliding surface is opposed to the recording medium in the notch portion. A magnetic head characterized in that the distance from the surface is greater on both sides near both ends in the sliding direction of the recording medium than on the side near the magnetic gap. 2. The magnetic head according to claim 1, wherein a thin-film coil for winding a magnetic layer is formed on at least one of the pair of magnetic head halves. 3. The recording medium according to claim 1, wherein a surface of the notch facing the recording medium is a curved surface, and a radius of curvature of the curved surface is smaller than a radius of curvature of a sliding surface of the recording medium.
The magnetic head as described.