JPH04318316A - Magnetic head - Google Patents

Abstract

PURPOSE:To highly accurately adjust the azimuth by making the thickness of a magnetic head to be disposed in a magnetic recording and reproducing device ununiform. CONSTITUTION:The adjustment of the azimuth of the magnetic head to be disposed in the magnetic recording and reproducing device is performed by utilizing irradiation energy of a laser. The thickness of an irradiated part 12 of a magnetic head base 11 is made different in its irradiated area to obtain displacement of the azimuth in this method. That is, when a thickness difference in the irradiated area is thicker on the right side as seen from the center of the magnetic head, the azimuth can be adjusted anticlockwise, and in the opposite case, the adjustment can be made clockwise. The similar azimuth adjustment is feasible in either case of this different thickness surface on the side of a magnetic head main surface 16 or the reverse side of this main surface.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for a magnetic recording/reproducing device used in a video tape recorder (hereinafter abbreviated as VTR).

0002

[Prior Art] The track format recorded on a conventional VTR has a track pitch of 60 μm in 2-hour mode.
In the 6-hour mode, track recording is extremely narrow at 20 μm. Moreover, the tape and the head must use a helical scan method to accurately carve this track pitch using two pairs of heads that are 180 degrees opposed to each other.

[0003] With such high-density recording, the influence of signals close to the head cannot be ignored, resulting in the problem of crosstalk. As a countermeasure to this problem, there is an idea of azimuth recording using a magnetic head. In VHS, the head gaps between the pair of magnetic heads H1 and H2 are set to have different azimuth angles. Tilt H1 by 6 degrees and make H2 angle 6 degrees in the opposite direction. In this method, crosstalk from adjacent tracks is removed using azimuth loss, and for another adjacent track with the same azimuth angle,
The reverse azimuth track in between is used as a guard band.

As shown in FIG. 2(a), a head chip 23 is bonded to a magnetic head base 22, and an upper cylinder 21 is attached.
Check the height of the other 180-degree opposing head with screws 24, and if the deviation is greater than the specified value, replace the previously installed magnetic head base 22 (Fig. 2(b)).
), the head chip height 28 was set by screwing in the direction of the arrow 27 to deform it.

FIG. 3 shows a conventional magnetic head made of brass material.
Shown in (a) and (b). The magnetic head 31 has a diameter of 1 mm to 2 mm.
mm thick, and in order to deform it with the insect screw 25, on the surface of the magnetic head 31 (FIG. 3(b)
), the surface 35 that joins the cylinder is entirely flat.

[0006]

[Problems to be Solved by the Invention] To adjust the azimuth of a magnetic head, simply create a specified azimuth angle at the time of manufacturing the magnetic head gap and install it on the magnetic head. It is also very difficult to convert the angle into minutes. If the magnetic head base on which the head chip is installed is deformed due to mechanical vibration or temperature change, the mounting magnetic angle will also change, making it impossible to maintain the initial accuracy. If the azimuth of the magnetic head of a VHS VTR remains misaligned and reproduction is performed on another VHS, a problem arises in that the output decreases due to the difference in azimuth angle.

[0007] Furthermore, although the azimuth angle of the magnetic head is adjusted using a magnifying screw as in the M2 VTR, there are various factors that generate vibrations, such as cylinder rotation and tape transport, and vibrations are generated from their drive systems. It is unavoidable that the azimuth angle will change due to temperature changes due to changes in heat over time or changes in the usage environment.

[0008]Currently, in an attempt to minimize the effects of these factors, screw loosening agents (resin that sticks at room temperature) are used for insect screws, but the effect is not sufficient; The head height changed on the order of , and the azimuth angle also changed.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention is directed to adjusting the azimuth of the magnetic head so that the thickness of the magnetic head is not uniform. Make sure that the thickness is not uniform. To set the thickness of the magnetic head unevenly, either the main surface of the magnetic head or the back side of the main surface is depressed, or a chevron-shaped protrusion with an oblique side is created on the main surface or the back side of the main surface of the magnetic head. do.

A thermal melting section is provided on the magnetic head to distort the magnetic head to adjust the azimuth of the magnetic head. 2. The magnetic head according to claim 1, wherein the thickness of the magnetic head at a position before becoming the thermally melted portion is different within the region that becomes the melted portion.

[0011]

According to the present invention, with the above structure, thermal energy is concentrated on the grooved portion on the magnetic head base, and the magnetic head base is deformed by being subjected to distortion due to shape deformation due to melting. This amount of deformation is inversely proportional to the square of the thickness of the irradiated portion for the same irradiation energy. In a magnetic head base in which the thickness of the irradiated portion differs diagonally, it is possible to obtain displacement of the magnetic head in the azimuth direction because a difference occurs in the amount of deformation of the tip of the magnetic head chip.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic head according to an embodiment of the present invention will be described below with reference to the drawings. (FIG. 1) shows the configuration of the magnetic head of the present invention. For example, a method for adjusting the azimuth of a magnetic head using laser irradiation energy is set. When the temperature of the part irradiated by the laser rises to half the melting point of the magnetic head base material, the magnetic head gap 14 in the azimuth direction is distorted.
The amount of change in angle is obtained. In this case, the irradiation position 12 is irradiated with a YAG laser, which is an irradiation light source, having an output of 300 watts and a laser beam focused to a diameter of 600 μm. For the same irradiation energy, the angular change of the magnetic head gap 14 in the azimuth direction is proportional to the square of the thickness difference within the irradiation area of the magnetic head. For example, the thickness of the magnetic head base 11 is made to have a trapezoidal cross section, and portions are cut off so that the thickness within the irradiation area is different. The thickness of the irradiated portion 12 of the manufactured magnetic head base 11 is 1.5 mm at its thickest point, and
When the thinnest point is 0.5 mm, one pulse time of the laser described above is 9 milliseconds and the energy of one pulse provides a rotational displacement of one degree in the azimuth direction of the magnetic head.

[0013] In this way, by setting the part of the magnetic head base that is a hypotenuse, the thickness in the irradiation depth direction within the laser irradiation area is made different. In addition, the irradiation surface is
Even on the oblique side on the magnetic head main surface 16 side, the magnetic head main surface back 18
Similar effects can be obtained with either flat surface.

The rotational direction of the azimuth is rotationally displaced in the direction in which the laser irradiation portion 12 is thinner. The hypotenuse of the magnetic head base is manufactured in the case of the right azimuth of the head gap and the case of the left azimuth.
If there is a type, it is possible to handle either an individual magnetic head with an azimuth that rises to the right or, conversely, a magnetic head with an azimuth that rises to the left. That is, the difference in the magnetic head base thickness can be adjusted to an angle that rotates to the left if the right side is thicker when viewed from the center of the magnetic head, and can be adjusted in the opposite direction if the magnetic head is thicker on the right side.

Furthermore, when adjusting the rotational angle of the azimuth in a magnetic head as shown in FIG. 4, the oblique side of the laser irradiation position 42 is irradiated and the angle is displaced to 7 degrees even though the set angle is 6 degrees. If 1 degree is excessive, when the laser is irradiated to the oblique side of the laser irradiation position 46 bordering on the apex 50 of the irradiation position 42, the irradiated part of the magnetic head base 1
Since the thickness relationship of 1 is opposite to that of the irradiation position 42, the rotational displacement in the azimuth direction is reversed and the excess of 1 degree can be recovered. Conversely, even if the adjustment angle becomes excessive by first irradiating the oblique side of the irradiation position 46, the same adjustment can be made by irradiating the irradiation position 42 later.

This magnetic head base 11 can also be provided to a multi-head base in which a plurality of head chip installation sections are provided on one magnetic head base, such as a multi-head, and in this case as well, the azimuth adjustment of the head is It is possible. Furthermore, even when a magnetic head is installed on a rotating cylinder, it is possible to efficiently adjust the azimuth of the head by irradiating only a certain oblique side of the magnetic head base with a laser while rotating.

When adjusting the set value of the azimuth angle by one irradiation, although there are differences depending on the irradiation energy, a part of the irradiation area may reach the melting point temperature and a melted portion may remain on the magnetic head. However, when using low energy irradiation with fine angle adjustment, the melted area may not be apparent.

The displacement obtained by laser irradiation does not change even under an environment of 500 degrees Celsius for one hour.

[0019]

As described in the above embodiments, according to the present invention, the azimuth angle of the magnetic head can be finely adjusted with a high degree of precision that has not been possible in the past. Even when multiple head chips are mounted on a single head base, which is the case with multi-heads, head azimuth adjustment can be performed with high precision. Furthermore, items adjusted by laser irradiation do not change due to daily environmental changes.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a magnetic head that is an embodiment of the present invention.

FIG. 2(a) is an explanatory diagram for explaining head installation using a conventional magnetic head using an insect screw. (b) is a partially enlarged view for explaining the head height adjustment by the pushing force of the insect screw of the conventional magnetic head of (a).

FIG. 3(a) is a front view of a conventional magnetic head base having a uniform thickness. (b) is a sectional view of a conventional magnetic head base having a uniform thickness.

FIG. 4 is a configuration diagram of a magnetic head with a protrusion according to an embodiment of the present invention.

[Explanation of symbols]

11 Magnetic head base 12 Irradiation position 13 Magnetic head chip 14 Magnetic head gap 15 Magnetic head winding through hole 16 Magnetic head main surface 17 Magnetic head base installation screw hole 18 Magnetic head main surface back 21 Cylinder 22 Magnetic head base 23 Head chip 24 Installation screw 25 Magnetic screw 27 Force direction of insect screw 28 Head chip height 31 Magnetic head base 32 Magnetic head base installation screw hole 34 Head winding hole 35 Surface to be installed on the cylinder side 41 Magnetic head base 42 Projection part Irradiation position 43 Magnetic head chip 44 Magnetic head gap 45 Magnetic head gap depth direction 46 Magnetic head irradiation position 47 on the protrusion Back main surface of magnetic head 48 Main surface of magnetic head 49 Hole for magnetic head base installation screw 50 Vertex

Claims (6)

[Claims] 1. A magnetic head characterized in that the thickness of the magnetic head is not uniform. 2. The magnetic head according to claim 1, wherein the azimuth angle of the magnetic head is adjusted by taking advantage of the fact that the thickness of the magnetic head within an irradiation area where the magnetic head is irradiated with light and heat is not uniform. . 3. The magnetic head according to claim 1, wherein the non-uniform thickness of the magnetic head is such that the main surface of the magnetic head or the back side of the main surface is depressed. 4. The magnetic head according to claim 1, wherein the non-uniform thickness of the magnetic head is such that the main surface of the magnetic head or the back side of the main surface has a chevron-shaped protrusion having an oblique side. 5. The magnetic head according to claim 1, wherein the azimuth of the magnetic head is adjusted by providing a thermal melting section on the magnetic head to distort the magnetic head. 6. The magnetic head according to claim 1, wherein the thickness of the magnetic head at a position before becoming a thermally melted portion is different within a region that becomes a melted portion.