JPH05250626A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve the characteristics of a magnetic head and to make the head adaptable even to a narrowed track by regulating the ratio of gap depth to track width to <=0.5. CONSTITUTION:A pair of core chips 16, 16 obtd. by coating soft magnetic thin films 2 formed on substrates 1 with low m.p. glass 3 are joined so that ends of the thin films 2 confront each other and a magnetic gap 15 is formed between the cross sections of the thin films 2. The ratio of gap depth to track width is regulated to <=0.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used for recording and reproducing information in a magnetic recording and reproducing apparatus such as a video tape recorder.

[0002]

2. Description of the Related Art With the increasing density of magnetic recording technology,
For example, a high coercive force medium such as a metal tape has become mainstream nowadays, and a core material used for a magnetic head is required to have a high saturation magnetic flux density.

At present, a magnetic head often used in a video tape recorder or the like is, as shown in FIG. 1 which is an explanatory view of the present invention, on a substrate 1.1 made of a non-magnetic material or an oxide magnetic material. Soft magnetic thin film 2 having high saturation magnetic flux density
2 is formed as a core material, filled with a filling material 3 such as low-melting glass, and then joined at a gap surface 13 through a non-magnetic gap material (not shown) to be used as a head chip 10. In this case, the length of the soft magnetic thin film 2 along the magnetic gap 13, that is, the gap width is made substantially equal to the recording track width Tw.

On the other hand, the gap depth Gd of the head chip 10 in FIG. 1 is often selected to be slightly large because it has been determined only by considering the life of the head. Therefore, the Gd of the head in the conventional magnetic head is selected. The / Tw value was about 1.4.

[0005]

However, regarding the magnetic head having the above-mentioned structure, for example, looking at the relationship between the loss in the gap and Gd / Tw, as shown in the experimental results of FIG. 2, the value of Gd / Tw is 0. The loss becomes the minimum when the value becomes 0.5 or less, and becomes saturated when the value of Gd / Tw is less than that. From this, it can be seen that the head performance can be fully utilized when the ratio is equal to or lower than the above ratio, but the performance of the head is not sufficient with the conventional magnetic head having a Gd / Tw value of 1.4.

Further, if the track width Tw of the conventional magnetic head is reduced so as to cope with the current narrow track, the Gd / Tw value further increases and the head loss characteristic further deteriorates. From this, it is understood that the current narrow track cannot be supported.

The present invention has been made in view of the above conventional problems, and an object thereof is to make the gap depth as small as possible, thereby making the Gd / Tw value as small as possible and improving the characteristics of the head. It is an object of the present invention to provide a magnetic head that can handle such a narrow track.

[0008]

The magnetic head of the present invention comprises:
A pair of core pieces, in which a soft magnetic thin film formed on a substrate is covered with a low melting point glass, are joined so that the end faces of the soft magnetic thin film face each other, and a magnetic gap is formed between the end faces of the soft magnetic thin film. Ratio Gd of gap depth Gd and recording track width Tw
The feature is that the value of / Tw is 0.5 or less.

[0009]

According to the above structure, the gap width of the magnetic head is considered to be a constant value because it is made almost equal to the recording track width Tw.

On the other hand, when the gap depth Gd is large, the facing surfaces of the gap become large, so the magnetic flux density decreases,
Recording loss increases. Therefore, the gap depth Gd
When the Gd / Tw value is made as small as possible and the Gd / Tw value is 0.5 or less, the loss is minimized and the characteristics of the head are improved as shown in FIG. As long as it is held, it is possible to cope with a narrow track.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. A head chip 10 used in the magnetic head of this embodiment will be described with reference to FIG. The head chip 10 is, for example, a photosensitive crystallized glass,
A substrate 1 made of crystallized glass, a non-magnetic material such as ceramics, or an oxide magnetic material such as soft magnetic ferrite, a soft magnetic thin film 2 having a high saturation magnetic flux density formed on the substrate 1, and a soft magnetic thin film. It is composed of a pair of core pieces 16 and 16 having a low-melting glass 3 that covers 2 The pair of core pieces 16 and 16 are arranged so that the end surfaces of the soft magnetic thin films 2 and 2 face each other so that the soft magnetic thin films 2 and 2 on the substrate 1 and 1 form a head core having the magnetic gap 15. It is joined at 13. Further, the sliding surface 17 is polished and finished to have a predetermined surface roughness so that the magnetic gap 15 and a magnetic recording medium such as a magnetic tape are brought into smooth contact with each other.

In the core piece 16, the soft magnetic thin film 2
Is formed along the groove 5 formed obliquely with respect to the gap surface 13, and is sandwiched between the substrate 1 and the low melting point glass 3. The head chip 10 has a gap surface 13 of the substrate 1 for winding a head coil (not shown) around the head core formed of the soft magnetic thin film 2.2.
Inner winding groove 11, 11 is formed on the
External winding grooves 12 and 12 are formed on the side opposite to 3. Then, the inner winding hole 11 is formed by the inner winding groove 11.

Here, the gap surface 1 of the magnetic gap 15
The length of the portion parallel to 3 is the track width Tw, and the film thickness of the soft magnetic thin film 2 in the magnetic gap 15 is the gap depth Gd. In this embodiment, the gap depth Gd is set to 0.5 times the track width Tw or less in order to set the Gd / Tw value to 0.5 or less.

A method of manufacturing the above magnetic head will be described with reference to FIGS.

As shown in FIG. 3, a predetermined pitch dimension A is formed on the surface of the substrate 1 made of the above non-magnetic material or oxide magnetic material.
, Which are substantially V-shaped, are formed in parallel. The grooves 5 are formed linearly from one end to the other end of the substrate 1,
It has a certain depth.

Next, as shown in FIG. 4, soft magnetic material having a high saturation magnetic flux density such as Fe--Al--Si alloy with a predetermined film thickness is formed on one side slope of the groove 5 by, for example, vacuum deposition or sputtering. The thin film 2 is formed. The soft magnetic thin film 2 has a constant film thickness along the groove 5 and is uniformly formed from one end to the other end.

Next, as shown in FIG. 5, the groove 5 formed in the substrate 1 is filled with the low melting point glass 3. At this time, the low melting point glass 3 is sufficiently filled so as to cover the tops of the grooves 5 provided in the substrate 1. Then, after the low-melting glass is solidified, as shown in FIG.
Is ground flat.

Thereafter, as shown in FIG. 7, in the head chip 10, a head coil (not shown) is wound around a head core composed of the soft magnetic thin films 2 and 2. The inner winding groove 11 is formed, and the outer winding groove 12 is formed on the opposite side of the gap surface 13 of the substrate 1. Further, a non-magnetic gap material such as SiO2 (not shown) is uniformly formed on the gap surface 13 by a method such as vacuum deposition or sputtering so that a predetermined gap is formed.
This is a substrate block 17.

Next, as shown in FIG. 8, the gap surfaces 13 of the substrate block 17 having the above structure are made to face each other, and the magnetic gap 15 is formed by the soft magnetic thin films 2.2.
The core block 20 is formed by aligning the positions so that the core block 20 can be formed. Next, the core block 2
A head chip 10 shown in FIG. 1 is obtained by cutting 0 at a predetermined pitch dimension B along the broken line in FIG.

After the head chip 10 is bonded and fixed to a base plate (not shown), the internal winding groove 1 is formed.
1 and the external winding groove 12 are used to perform winding to form a head coil and a sliding surface 1 with a magnetic recording medium such as a magnetic tape.
A magnetic head is formed by tape-polishing 7. At this time, the gap depth Gd is set to 0.
The magnetic head of the present embodiment is obtained by polishing so as to be 5 times or less.

In the above structure, the head chip 10 used for the magnetic head is manufactured so that the Gd / Tw value at the gap depth Gd and the track width Tw is 0.5 or less. Here, the reason why the Gd / Tw value is set to 0.5 or less will be described below.

First, FIG. 2 shows the relationship between the ratio of the gap depth Gd to the track width Tw in the head chip 10 and the loss in the gap, for example. From the graph shown in this figure, it can be seen that the performance of the head can be brought out by setting the loss characteristic value of the head to a saturated state when the Gd / Tw value is 0.5 or less and setting it to the above ratio or less.

Further, if the Gd / Tw value is always set to 0.5 or less, the head characteristic does not deteriorate even if the track width is reduced, so that the track can be narrowed. From the above, the value of Gd / Tw in the present invention was determined.

On the other hand, since the gap depth Gd in the conventional magnetic head is determined only by the life of the head, it is larger than the track width, and Gd / T
The w value is about 1.4. From FIG. 2, when the Gd / Tw value is 1.4, the performance of the head cannot be sufficiently obtained.

When the track width Tw is reduced, G
Since the d / Tw value becomes larger than 1.4, it can be seen that it is not possible to cope with the narrow track.

Therefore, from the above, the gap depth G
By setting d to be 0.5 times or less of the track width Tw,
The characteristics of the magnetic head can be improved, and it is possible to deal with narrower tracks.

The gap depth Gd is set to the track width Tw.
When a problem occurs in terms of the life of the head when it is 0.5 times or less, it is necessary to consider that the soft magnetic thin film forming the core and the material of the substrate have higher hardness.

[0028]

As described above, the magnetic head of the present invention has the following features.
A soft magnetic thin film formed on a substrate is covered with a low melting point glass, and a pair of core pieces are joined together so that the cross sections of the soft magnetic thin film face each other, and a magnetic gap is formed between the cross sections of the soft magnetic thin film. In the head, the ratio of the gap depth Gd in the soft magnetic thin film to the track width Tw, Gd / Tw, is 0.5 or less.

With the above configuration, the value of Gd / Tw is set to 0.
By setting the ratio to 5 or less, it is possible to improve the characteristics of the head, and it is possible to cope with the future narrowing of the track.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a head chip used in a magnetic head of the present invention.

FIG. 2 is a diagram showing an experimental result showing a relationship between a ratio of a track width Tw and a gap depth Gd and a loss in a gap according to the present invention.

FIG. 3 is a perspective view showing a manufacturing process of the magnetic head of the present invention and showing a process of forming a V-shaped groove.

FIG. 4 is a front view showing a step of forming a soft magnetic thin film on one side slope of the V-shaped groove of FIG.

5 is a front view showing a step of filling low melting point glass on the soft magnetic thin film formed in FIG. 4. FIG.

6 is a front view showing a step of polishing the low melting point glass filled in FIG. 5 into a flat surface to form a gap surface 13. FIG.

FIG. 7 is a perspective view showing a step of forming an inner winding groove and an outer winding groove on both side surfaces of the substrate of FIG. 6 to produce a core block.

FIG. 8 is a perspective view showing a step of forming a magnetic head block by combining the core blocks of FIG. 7 with each other.

[Explanation of symbols]

 1 substrate 2 soft magnetic thin film 3 low melting glass 15 magnetic gap 16 core piece

Claims (1)

[Claims] 1. A pair of core pieces obtained by covering a soft magnetic thin film formed on a substrate with low melting point glass are joined so that the end faces of the soft magnetic thin film face each other, and between the end faces of the soft magnetic thin film. In a magnetic head having a magnetic gap, the ratio of the gap depth Gd to the recording track width Tw Gd / T
A magnetic head having a value of w of 0.5 or less.