JP2946802B2 - Manufacturing method of magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the height of a magnetic head in a magnetic storage device using a rotating cylinder.

[0002]

2. Description of the Related Art The positioning accuracy of a magnetic head used in a magnetic recording / reproducing apparatus is an important accuracy for determining the format of information recorded on a medium.

[0003] For example, in a video tape recorder widely used for home use, a rotating cylinder has an angle of 180 °.
Two pairs of magnetic heads mounted opposite to each other record and reproduce image and audio information while sequentially scanning the magnetic tape in an oblique direction. The track pitch actually recorded on the magnetic tape is as extremely small as 60 μm in the 2-hour mode and 20 μm in the 6-hour mode.

If the two pairs of magnetic heads cannot scan these tracks accurately, the recorded information cannot be accurately reproduced, and the quality of the reproduced image is significantly reduced. To prevent this, the scanning pitch of the magnetic head must be accurately adjusted to the track pitch described above. An important factor that determines the scanning pitch is the height of the magnetic head.

The height of the magnetic head is the distance (H in FIG. 3) between the reference surface 5 of the lower cylinder 2 and the gap end of the head fixed to the upper cylinder 1 shown in FIG. It is.

A conventional head height adjusting method will be described below with reference to FIG. However, FIG. 4 is a diagram showing a cross section of the upper cylinder portion in FIG.

First, after roughly adjusting a spacer (not shown) having a predetermined thickness between the upper cylinder 1 and the head base 4 to which the head chip 3 is attached, the head height is adjusted using the objective lens 6. While observing the above, a screw 7 that is in contact with a part of the head base 4 is screwed in the direction of the arrow 8 in the necessary adjustment amount (FIG. 5), and the head base is partially deformed to thereby obtain a predetermined head. Adjust to the height.

[0008]

The basic principle of the conventional adjustment using a screw is that the head base is deformed by the pushing force of the screw within the limit of the elastic deformation of the head base. In such a case, if the pushing amount of the insect screw changes due to mechanical vibration or temperature change, the deformation amount of the head base changes by that amount, and eventually the head height may change.

In an actual VTR, there are various factors that generate vibrations such as rotation of a cylinder and tape transport, and temperature change due to a change with time of heat generated from the driving system or a change in a use environment should be avoided. I can't.

At present, in order to minimize the influence of these factors, a screw loosening preventive (resin that is fixed at room temperature) is used for the insect screw, but the effect is not sufficient, and several microns are required. Had changed the head height. This change in head height is one of the important factors that affect the image quality of a VTR.

When a fluid bearing is used as a bearing for a rotating cylinder, the relative position of the rotating upper cylinder with respect to the lower cylinder changes due to the rotation of the shaft. It was difficult to do so, and after all, the adjustment work had to be trial and error.

Further, the actual adjustment work using a screw is manually performed, which is rather complicated.

An object of the present invention is to solve the above-mentioned problems and to provide a method capable of adjusting the head height of a magnetic head with high accuracy and high efficiency without being affected by vibration or temperature change. .

[0014]

In order to achieve this object, a method of manufacturing a magnetic head according to the present invention comprises the steps of:
Head and a head bed for holding the head in the cylinder.
A recording / reproducing apparatus having a head base.
Irradiates the head with laser light to adjust the head height.
A method of manufacturing a raw device , wherein a deformation state of the head base is adjusted by controlling a focus state of the laser light in a laser irradiation unit of the head base.
It is .

[0015]

According to the present invention, the head height can be adjusted even when the upper cylinder is rotated by using laser processing capable of deforming the head base in a non-contact manner.
Moreover, since the energy density at the irradiated portion of the head base is controlled by adjusting the focus of the laser beam, and the amount of deformation of the head base is adjusted, high-precision adjustment can be quickly performed under laser processing conditions to obtain a stable laser output. It has the effect.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment for adjusting the height of a magnetic head according to the present invention will be described with reference to FIG. A 1.5 mm thick head base 4 made of brass and having a head chip 3 attached thereto is attached to the upper cylinder 1.
Was fixed to the lower cylinder 2 by a fluid bearing (not shown). Next, when the head height was measured using the objective lens 6 while rotating the upper cylinder 1 at a regular rotation speed, it was found that a deformation adjustment of 12.3 μm was required to a predetermined head height.

In this embodiment, the laser beam 11 is N
d: Short pulse oscillation of a YAG laser (wavelength 1.06 μm) was used. Also, the pulse width of the excitation flash light is set to 1
The laser energy obtained when the excitation voltage was 450 volts for msec was about 1 Joule per pulse.

The upper cylinder is provided with a through hole 9 for passing a laser beam. This through hole has a length of 8 mm in an arc shape extending in the rotation direction of the arrow in the figure. In order to transmit the above-mentioned laser light while actually rotating, the laser oscillation was synchronized with the rotation of the upper cylinder 1.

The actual laser beam 11 under the conditions described above
The deformation of the head base due to the above will be described below.

FIG. 2 is a graph showing the relationship between the irradiation distance d and the amount of deformation of the head base, obtained by an experiment conducted in advance using a dummy head base of the same material and shape. As is clear from this figure, it has been found that there is a proportional relationship between the irradiation distance d and the deformation amount of the head base.

Therefore, based on this result, the irradiation distance d is set to 3
When the actual head base was deformed to 9 mm, the obtained deformation amount was 12.0 μm, which was a deviation of only 0.5 μm from the target.

In another embodiment, the required deformation amount is 1
In the case of 5.7 μm, the distance d was divided into multiple stages, and the laser irradiation positions were deformed while being shifted by 0.1 mm. The reason for dividing into multiple stages is to perform the measurement at any time using the additivity of the welding deformation, thereby grasping the target deformation amount again and deforming more accurately. The reason why the irradiation position is shifted by 0.1 mm is to prevent a change in absorptivity of laser energy due to a change in surface properties after irradiation.

Actually, the first deformation was performed with the irradiation distance d set to 29 mm. As a result, the deformation was 9.3 μm. Therefore, the remaining required deformation amount was 6.4 μm. Subsequently, the irradiation position was shifted by 0.1 mm toward the center of rotation, and the second deformation was performed with the irradiation distance d of 17 mm. The deformation amount at this time was 4.2 μm, and was still 2.2 μm short. Therefore, the irradiation distance d is set to 7.5 mm and 3
The result of the second deformation was 2.1 μm. The finally obtained amount of deformation is 0.1 μm shifted from the target by 1.
It was 5.6 μm.

The reason why such high-precision deformation can be performed is that the laser beam can be driven in with a small deformation amount with little error under stable laser emission conditions.

Since the head height adjustment according to the present invention described above does not use a screw, and is based on the plastic deformation of the head base, there is no influence of mechanical vibration or temperature change which has been a problem in the past. I do not receive. In fact, -40
C. and 80.degree. C., and the deformation of the head base before and after the test was 0.1%.
It did not change with an accuracy of less than μm.

In this embodiment, since the fluid bearing is used, the head height is adjusted while rotating the cylinder. However, according to the present invention, in the case of a bearing other than the fluid bearing, for example, a bearing using a bearing is used. In, the head height can be adjusted while the cylinder is stationary.

In this embodiment, the irradiation distance d is changed as the focus control. However, without changing the irradiation distance, the irradiation distance d is changed by changing the focal position of the lens system. It is clear that the effect of (1) is obtained.

Further, the relationship between the irradiation distance d and the amount of deformation can be used as data to automate the laser irradiation and the drive system and measurement system of the condenser lens by computer control. By automating this series of adjustment work, it becomes possible to incorporate it into the actual VTR mass production line, and it will be possible to perform more accurate and reliable head height adjustment more quickly than before. It is clear.

[0029]

According to the present invention, as described in the above embodiment, there is an advantage that the head height can be adjusted with high accuracy while the cylinder is rotating only by controlling the focus state of the laser beam. V by automating
It can be incorporated into a TR mass production line, and its productivity is dramatically improved. Further, according to the present invention, since the head height is not affected by mechanical vibration or temperature change, it is easy to realize a high-quality VTR by narrowing the track.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a main cross section of an upper and lower cylinder and a head height adjusting mechanism using laser light according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between an irradiation distance d and a deformation amount of a head base in the present invention.

FIG. 3 is an explanatory diagram for explaining a definition of a head height.

FIG. 4 is a sectional view of an upper cylinder for explaining a conventional head height adjusting method.

FIG. 5 is an enlarged view of a main part of the upper cylinder of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper cylinder 2 Lower cylinder 3 Head chip 4 Head base 5 Reference surface 6 Objective lens 7 Insect screw 8 Screw screw screw-in direction 9 Through hole 10 Condensing lens 11 Laser light 12 Head base surface

────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Yoshiaki Maekawa 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) G11B 5/56

Claims (2)

(57) [Claims] A cylinder, a head, and the head;
A recording base having a head base held by the cylinder;
In the raw device, the head base is irradiated with laser light.
A method for manufacturing a recording / reproducing apparatus for adjusting the head height by
It, by controlling the focus state of the laser light in the head-based laser irradiation portion, the magnetic head is characterized in that adjusting the amount of deformation of the head base
Production method. Wherein the head base of the deformation, in the laser beam
2. The method according to claim 1, wherein the step is performed in multiple stages by changing the center position .