JPH08203024A - Magnetic head - Google Patents

Abstract

PURPOSE: To provide a highly efficient magnetic head capable of giving a wide sectional area of a back gap without any failures when a pair of magnetic core half blocks are coupled together with a simple structure. CONSTITUTION: A magnetic head is provided, wherein a pair of magnetic core half blocks composed of a thin film coil 4 and a magnetic core half body 10a formed on a substrate are coupled together so that the coil connecting terminals 4a and 4b of the thin film coil 4 of one magnetic core half block 10b are connected to the coil connecting terminals 4a and 4b of the thin film coil of the other magnetic core half block. The coil connecting terminals 4a and 4b of this thin film coil 4 are disposed so as to surround the back gap section 2bg of the magnetic core half body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head suitable for a video tape recorder, a video cassette recorder, a magnetic disk device, etc., and more particularly to a magnetic head formed by forming a thin film coil by a thin film forming process.

[0002]

2. Description of the Related Art In recent years, high density recording of information signals has been advanced in the field of magnetic recording such as video tape recorders, video cassette recorders, magnetic disk devices, etc. Therefore, for a magnetic head that is responsible for recording and reproduction, high efficiency is achieved by downsizing the magnetic core,
Low inductance is required by thinning the coil,
Along with this, processing of the magnetic head has become complicated and precise.

A small magnetic head using such a thin film coil is, for example, as shown in FIG. 14, a pair of magnetic heads in which a magnetic layer 12 serving as a magnetic core and a thin film coil 14 are formed on a substrate. The half bodies 110a and 110b are joined together.

Here, a pair of magnetic head halves 110a,
110b connects the coil connection terminal 14c located at the center of the thin film coil 14 of the one magnetic head half body 110a and the coil connection terminal 14c located at the center of the thin film coil 14 of the other magnetic head half body 110b. , A portion of one magnetic head half 110a on the front gap side of the magnetic layer 12, that is, the front gap portion 12fg.
And the front gap portion 12fg of the other magnetic head half body 110b abut against each other to form a front gap, and the back gap side portion of the magnetic layer 12 of one magnetic head half body 110a, that is, the back gap portion. 12bg and the back gap part 12bg of the other magnetic head half 110b are butted against each other and joined so as to form a back gap.

Here, as shown in FIG. 15, the thin-film coil 14 is patterned around the back gap portion 12bg so that the coil connecting terminal 14c is located below the back gap portion 12bg.
Then, the thin film coil 14 of one magnetic head half 110a
And the thin film coil 14 of the other magnetic head half 110b are connected.

[0006]

By the way, in the above-described magnetic head, not only the pair of magnetic head halves are joined so as to form the back gap and the front gap, but also the thin films of the respective magnetic head halves are joined. It is necessary to join the coils so that they are connected at the coil connection terminals, and the structure is complicated.

Since the structure is complicated, it is difficult to join the magnetic head halves, and there are many defects during joining. Specifically, when the front gap part and the back gap part are projected more than the coil connection terminal part of the thin film coil, the connection between the thin film coils becomes insufficient when the pair of magnetic head halves are joined. Will end up. On the contrary, if the coil connection terminal portion of the thin-film coil is projected more than the front gap portion and the back gap portion, the front gap and the back gap are appropriately formed when joining the pair of magnetic head halves. It's gone.

Further, in the magnetic head as described above, since it is necessary to secure the area of the coil connection terminal portion of the thin film coil, the cross-sectional area of the back gap portion is limited, and the efficiency of the magnetic head can be improved. difficult. Although it is possible to increase the cross-sectional area of the back gap by increasing the diameter of the thin film coil, increasing the diameter of the thin film coil increases the total length of the thin film coil and increases the resistance value. Therefore, it is still difficult to improve the efficiency of the magnetic head.

Therefore, the present invention has been proposed in view of such a conventional situation, has a simple structure, has few defects when joining a pair of magnetic head halves, and has a cross-sectional area of the back gap portion. It is an object of the present invention to provide a highly efficient magnetic head capable of taking a wide range.

[0010]

In order to achieve the above object, the magnetic head of the present invention comprises a pair of magnetic head halves each having a thin film coil and a magnetic core formed on a substrate. A magnetic head in which a coil connecting terminal of a thin film coil of a half body and a coil connecting terminal of a thin film coil of the other magnetic head are joined so as to be connected, and the coil connecting terminal of the thin film coil is a magnetic core. It is in contact with the back gap part of.

Here, the coil connection terminal of the thin film coil is
For example, it is arranged so as to surround the back gap portion of the magnetic core.

The pair of magnetic head halves are joined by, for example, gold joining.

The magnetic core preferably has a laminated structure in which a plurality of metal magnetic films are laminated with an insulating film interposed therebetween in order to reduce eddy current loss.

[0014]

In the magnetic head of the present invention, since the coil connection terminal of the thin film coil is in contact with the back gap portion of the magnetic core, the coil connection terminals of the respective magnetic head halves are connected through the back gap. Therefore, the structure is very simple.

Since the formation of the back gap and the connection of the coil connection terminals of the respective magnetic head halves can be combined, the magnetic head halves can be easily joined, and the magnetic head halves are not properly joined. Is less likely to occur.

Since the back gap part of the magnetic core and the coil connecting terminal of the thin film coil are formed at the same place,
The cross-sectional area of the back gap portion is not limited by the coil connection terminal portion of the thin film coil, and the back gap portion can have a large cross-sectional area.

[0017]

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 is a magnetic head used for a video tape recorder, a video cassette recorder, etc., and as shown in FIGS. 1 and 2, a pair of magnetic head halves 10a, 10b has a magnetic gap. They are joined and integrated so as to abut each other via g.

Here, the magnetic head halves 10a, 10b
Is a substrate 1, a magnetic layer 2 formed on the substrate 1 and functioning as a magnetic core, and a glass 3 filled on the magnetic layer 2.
And a thin film coil 4 formed on the glass 3 portion by a thin film forming process.

The pair of magnetic head halves 10a, 1
0b is bonded via a non-magnetic material so that the respective magnetic layers 2 abut each other and a front gap fg and a back gap bg are formed between the respective magnetic layers 2.
The thin film coils 4 formed on the pair of magnetic head halves 10a and 10b are connected via a back gap bg.

The magnetic head will be described in detail below through its manufacturing method.

First, as shown in FIG. 3, MnO--NiO.
A substrate 1 made of a non-magnetic material such as a system is prepared. Here, the size of the substrate 1 is, for example, about 30 mm in length and about 30 m in width.
m and the thickness is about 2 mm.

Next, as shown in FIG. 4, in order to form an inclined surface on which a magnetic core is formed, a plurality of magnetic core grooves 1a are formed on one side of the magnetic core groove 1a. It is formed in parallel and at equal intervals so as to form an inclined surface. The magnetic core groove 1a has a depth of about 130 μm and a width of about 150 μm, for example, using a grinding wheel having one surface molded at about 45 degrees.
Dozens are formed so that the inclination of the inclined surface is about 45 degrees. Here, the inclination of the inclined surface does not have to be 45 degrees, but is preferably about 45 degrees in consideration of the pseudo gap and the track width accuracy.

Next, the substrate 1 on which the magnetic core groove 1a is formed
As shown in FIG. 5, the magnetic layer 2 is formed thereon. Here, the magnetic layer 2 may be composed of a single magnetic film, but in order to have high sensitivity in a high frequency region, a plurality of metal magnetic films are laminated by interposing an insulating film. You had better. However, in the case where the magnetic layer 2 has a laminated structure as described above, the thickness of the insulating film needs to be such that a sufficient insulating effect can be obtained, and is made as thin as possible so that the insulating film does not act as a pseudo gap. There is a need.

Therefore, in this embodiment, the magnetic layer 2 is made of sendust (Fe-Al-Si alloy) and has a thickness of about 5 μm.
Made of alumina and a metal magnetic film of about 0.15 μm thick
And the insulating film of No. 1 were alternately laminated so that the metal magnetic film had three layers. As described above, by forming the magnetic layer 2 into a laminated structure, eddy current loss is reduced, and higher sensitivity can be obtained especially in a high frequency region.

As a method for forming the magnetic layer 2, sputtering is suitable, but vapor deposition or molecular beam epitaxy (MB
A physical film forming method (PVD) other than sputtering such as E) or a chemical film forming method (CVD) may be used.

The material of the metal magnetic film is preferably sendust, but other metal magnetic materials such as an alloy similar to sendust, a nitriding type soft magnetic alloy, and a carbonizing type soft magnetic alloy can also be used. . Also, the insulating film is not limited to alumina, and SiO ₂ , SiO, or a mixture thereof can be used.

Next, as shown in FIG. 6, the magnetic core groove 1a is formed.
Winding groove 1 for arranging thin film coil 4 at right angles to
b and a separation groove 1c for separating the magnetic layer 3 for each magnetic core are formed.

Here, as shown in FIG. 2, the winding groove 1b has a shape in which the magnetic layer 2 on the front gap side is slanted toward the front gap fg.
For example, the front gap side of the winding groove 1b is formed by a grindstone having a slope of about 45 degrees. As described above, when the magnetic layer 2 on the front gap side 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 1b is such that the magnetic layer 2 on the front gap side is narrowed toward the front gap fg, the angle of the slope on the front gap side of the winding groove 1b is not 45 degrees. Further, the shape of the winding groove 1b on the front gap side may be an arc shape or a polygonal shape. Further, the depth of the winding groove 1b may be a depth that does not divide the magnetic layer 2,
If it is too deep, the magnetic path length increases and the magnetic flux transmission efficiency decreases. Therefore, in this embodiment, the winding groove 1b is formed to a depth of about 20 μm from the apex of the slope of the magnetic core groove 1a. The width of the winding groove 1b is determined by the width of the thin-film coil 4 and the number of windings to be formed in a later step, and in this embodiment, it is set to about 140 μm.

On the other hand, the separation groove 1c may have any shape as long as the magnetic layer 2 is divided, and has, for example, a rectangular shape that can be easily processed. The depth of the separation groove 1c needs to be such that the magnetic layer 2 is completely divided. In the present embodiment, the separation groove 1c extends from the bottom of the magnetic core groove 1a to a depth of about 150 μm.
c was formed. In addition, the length of the front gap portion 2fg, which is the front gap side portion of the magnetic layer 2, and the magnetic layer 2
Back gap portion 2bg which is a back gap side portion of
The width of the separation groove 1c that defines the length of the back gap b is the desired length of the front gap fg of the magnetic head and the back gap b.
It is determined by the trade-off of the length of g. However, the length of the front gap portion 2fg is set longer than the finally desired length of the front gap portion 2fg because the medium sliding surface is lapped when the magnetic head is finally processed into a predetermined shape. Then, the separation groove 1c is formed. Therefore, in this embodiment, the length of the front gap portion 2fg is about 300 μm and the length of the back gap portion 2bg is about 85 μm.
The separation groove 1c was formed to have a thickness of μm.

Next, as shown in FIG. 7, the magnetic core groove 1
A, the winding groove 1b, and the separation groove 1c are melt-filled with the glass 3 having a low melting point, and then the surface is mirror-finished.

Next, by the thin film forming process, as shown in FIG. 8, the thin film coil 4 is formed on the glass 3 portion for each magnetic core so as to pass through the winding groove 1b. However,
In order to lead the external connection terminals 4b to the outside, the thin film coils 4 are formed by alternately forming one row of thin film coils 4 having different external connection terminal 4b portions, as shown in FIG.

When forming such a thin film coil 4,
First, as shown in FIG. 9, a portion where the thin film coil 4 is arranged is etched to form a recess 4a of about 4 μm,
A resist is patterned in the recess 4a according to the shape of the thin film coil 4. Here, as shown in FIG. 10, the pattern of the thin film coil 4 is patterned so that the coil connection terminal 4c located at the center of the thin film coil 4 is in contact with the periphery of the back gap portion 2bg. Then, after patterning the resist, electrolytic plating of Cu or the like is performed to obtain about 3
The thin film coil 4 having a thickness of about μm is formed. Although the thin-film coil 4 is formed by electrolytic plating in this embodiment, it goes without saying that it may be formed by sputtering, vapor deposition, or the like.

By arranging the coil connection terminals 4c around the back gap portion 2bg in this way, the cross-sectional area of the back gap portion 2bg is not restricted by the coil connection terminal 4c portion of the thin film coil 4. Therefore, as compared with the case where the coil connection terminal 4c and the back gap portion 2bg are formed apart from each other as in the conventional magnetic head,
The cross-sectional area of the back gap portion 2bg can be made more than double, and the efficiency of the magnetic head is improved.

Further, when the cross-sectional area of the back gap portion 2bg is the same as that of the conventional magnetic head, the diameter of the thin film coil 4 can be made smaller. By reducing the diameter of the thin-film coil 4, the total length of the thin-film coil 4 is shortened, the resistance value of the thin-film coil 4 is lowered, the efficiency of the magnetic head is improved, and the magnetic head can be made smaller. .

Further, by arranging the coil connection terminals 4c around the back gap portion 2bg in this way, the formation of the back gap bg also serves as the connection of the coil connection terminals 4c of the respective magnetic head halves 10a and 10b. It will be. Therefore, the magnetic head halves 10a, 10b
Of the magnetic head halves 10a and 10b are easily joined, and defects are less likely to occur when the magnetic head halves 10a and 10b are joined.

Next, the pair of magnetic head halves 10a, 10
In order to bond b to gold, as shown in FIG. 11, an Au thin film 5 is patterned on a portion which becomes a joint between the magnetic head halves 10a and 10b. At this time, as shown in FIG. 12, the Au thin film 5 is also formed on the coil connection terminal 4c and the back gap portion 2bg. When the pair of magnetic head halves 10a and 10b are joined by the coil connecting terminal 4c and the Au thin film 5 on the back gap portion 2bg,
The back gap bg is formed, and the thin film coils 4 of the magnetic head halves 10a and 10b are connected to each other.

Next, as shown in FIG. 13, the substrate 1 on which the magnetic cores, the thin film coils 4 and the like are formed is cut row by row for each magnetic core to prepare magnetic head half blocks 11a and 11b. The pair of magnetic head half blocks 11a and 11b thus manufactured are joined by gold joining so that the magnetic layers 2 are abutted. However, if the magnetic head half blocks 11a and 11b are joined so that the coil connection terminals 4c of the thin film coils 4 of the respective magnetic head half blocks 11a and 11b are conducted, a chemical agent such as an adhesive is used. You may join by a typical joining method.

Finally, the magnetic cores are cut one by one, processed into a predetermined shape, and a pair of magnetic head halves 10a and 10b as shown in FIG. 1 are joined. A magnetic head is manufactured.

In the above-mentioned embodiment, the magnetic head half block is prepared by cutting the substrate on which the magnetic layer, the thin film coil and the like are formed one by one for each magnetic core. After joining, each magnetic core was cut one by one, but the magnetic layer, thin-film coil, and other substrates were cut in advance for each magnetic core to create a magnetic head half body. The head halves may be bonded to each other, or the substrates on which the magnetic layers and the thin film coils are formed may be bonded as they are, and then the magnetic cores may be cut one by one.

Further, in the above embodiment, the coil connecting terminal is formed so as to be in contact with the periphery of the back gap portion.
The shape of the coil connection terminal is not particularly limited as long as the back gap portion and the coil connection terminal are simultaneously covered with the Au thin film arranged on the coil connection terminal and the back gap portion. May be formed so as to contact only the lower part or the upper part of the back gap part, or only the left side or the right side.

[0042]

As is apparent from the above description, the magnetic head of the present invention has a very simple structure because the coil connection terminals of the respective magnetic head halves are connected at the back gap. Since the back gap can be formed and the coil connection terminals of the respective magnetic head halves can be connected together, the magnetic head halves can be easily joined, and a defect is less likely to occur when the magnetic head halves are joined. .

Further, since the back gap part of the magnetic core and the coil connecting terminal part of the thin film coil are located at the same place, the cross sectional area of the back gap part is not limited by the coil connecting terminal part of the thin film coil. Therefore, if the size of the magnetic head is the same as that of the conventional magnetic head, the cross-sectional area of the back gap portion can be made larger than that of the conventional magnetic head, so that the efficiency of the magnetic head can be improved. Further, when the cross-sectional area of the back gap portion is the same as that of the conventional magnetic head, the diameter of the thin film coil can be made smaller than that of the conventional magnetic head.
The resistance value of the thin-film coil can be reduced to improve the efficiency of the magnetic head, and the magnetic head can be made smaller.

[Brief description of drawings]

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

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

FIG. 3 is a perspective view showing an example of a substrate.

FIG. 4 is a perspective view showing an example of a state in which a magnetic core groove is formed on a substrate.

FIG. 5 is a perspective view showing an example of a state in which a magnetic layer is formed on a substrate.

FIG. 6 is a perspective view showing an example of a state where winding grooves and separation grooves are formed on a substrate and a magnetic layer.

FIG. 7 is a perspective view showing an example of a state where glass is filled in the magnetic core groove, the winding groove, and the separation groove.

FIG. 8 is a perspective view showing an example of a state in which a thin film coil is formed.

FIG. 9 is a front view showing an example of a thin film coil pattern of a pair of magnetic head halves.

FIG. 10 is an enlarged front view showing an example of a thin film coil pattern in the vicinity of a back gap portion.

FIG. 11 is a perspective view showing an example of a state in which an Au thin film is patterned.

FIG. 12 is a schematic diagram showing how an Au thin film is patterned on a back gap part and a coil connection terminal.

FIG. 13 is a perspective view showing an example of how a pair of magnetic head half blocks are joined together.

FIG. 14 is a front view showing a thin film coil pattern of a pair of magnetic head halves constituting a conventional magnetic head.

FIG. 15 is an enlarged front view showing the vicinity of a back gap portion of a thin film coil pattern of a conventional magnetic head.

[Explanation of symbols]

 1 Substrate 1a Magnetic Core Groove 1b Winding Groove 1c Separation Groove 2 Magnetic Layer 2fg Front Gap Part 2bg Back Gap Part 3 Glass 4 Thin Film Coil 5 Au Thin Film 10a, 10b Magnetic Head Half 11a, 11b Magnetic Head Half Block g Magnetic Gap fg front gap bg back gap

Claims (4)

[Claims] 1. A pair of magnetic head halves each having a thin film coil and a magnetic core formed on a substrate, a coil connecting terminal of a thin film coil of one magnetic head half, and a thin film coil of the other magnetic head half. A magnetic head formed by joining the coil connecting terminal and the coil connecting terminal so that the coil connecting terminal of the thin film coil is in contact with the back gap portion of the magnetic core. 2. The magnetic head according to claim 1, wherein the coil connection terminal of the thin film coil is arranged so as to surround the back gap portion of the magnetic core. 3. The magnetic head according to claim 1, wherein the pair of magnetic head halves are joined by gold joining. 4. The magnetic head according to claim 1, wherein the magnetic core is formed by laminating a plurality of metal magnetic films with an insulating film interposed therebetween.