JPH07105014B2 - 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 magnetic head used in a video tape recorder (hereinafter abbreviated as VTR).

[0002]

2. Description of the Related Art A conventional VTR recorded track format has a track pitch of 60 μ in a 2-hour mode.
It has a very narrow track recording of 20 μm in m, 6 hours mode. Moreover, the tape and the head are required to accurately mark the track pitch by two pairs of heads facing each other by 180 degrees by the helical scan method.

As shown in FIG. 2 (a), the head chip 23 is adhered to the head base 22 and joined to the upper cylinder 21 with the screw 24, and the head height of the other 180 degrees opposite is confirmed and specified. When there is a deviation from the value, the preinstalled magnetic head base 22 is deformed by screwing the insect screw 25 in the direction of the arrow 27 as shown in FIG. Had been set.

A conventional magnetic head made of brass is shown in FIGS. 3 (a) and 3 (b). The magnetic head base 14 is 1
The thickness of the magnetic head base 14 is made to be deformed by the screw 25.
A surface 18 to be joined to the cylinder as shown in FIG. 3 (b).
Is flat throughout.

[0005]

The basic principle of the conventional adjustment using the insect screw is that the deformation of the magnetic head base due to the pushing force of the insect screw within the limit of the elastic deformation of the magnetic head base is utilized. is there. 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 magnetic head base changes by that amount, and eventually the head height may change.

Actual VTR has various factors that generate vibrations such as cylinder rotation and tape transport, and avoids temperature changes due to changes with time of heat generated from these drive systems and changes in operating environment. I can't.

At present, a screw loosening preventive agent (resin that is fixed at room temperature) is used for insect screws in an attempt to minimize the influence from these factors, but the effect is not sufficient, and it is several microns. The head height had changed in the order of.

In the magnetic head base 14 having a flat surface as described above, for example, when the head height is adjusted by laser processing, in order to efficiently deform the magnetic head base 14, the laser heat irradiation point 13 and the magnetic head are used. The longer the distance from the head to the head of the base, the larger the amount of deformation can be obtained with the same energy. However, the current magnetic head base has a problem that the heat irradiation point 13 and the head at the tip of the magnetic head base are short and cannot be efficiently deformed.
The adjustment work with the actual insect screw is done by human hands,
It was quite complicated.

In the conventional height adjustment of the magnetic head chip by the deformation of the insect screw 25 and the magnetic head base 22, the head height is changed when looseness of the insect screw occurs due to mechanical vibration or environmental change. However, since it is not possible to secure an accurate recording track pitch, there is a method of improving the head height by laser processing in a non-contact manner as an improvement. However, when a conventional magnetic head base is irradiated with heat such as a laser, displacement can be obtained only in the direction of irradiation, and if the target displacement amount is exceeded, displacement in the opposite direction can be obtained with the conventional magnetic head shape. There is a problem that can not be done.

[0010]

In order to solve the above-mentioned problems, the present invention provides a recessed portion in a part of a magnetic head base and irradiates the recessed portion with light rays or heat so that the height direction of the magnetic head is increased. The height of the magnetic head is adjusted by obtaining the displacement. In addition, the depth of the hollow portion of the magnetic head is more than half the thickness of the main surface of the magnetic head.

[0011]

According to the present invention, the heat energy is concentrated on the hole-machined portion on the magnetic head base by the above-described structure, and the magnetic head base is deformed by being deformed by melting due to the shape deformation. In this case, as the displacement amount of the magnetic head, the displacement amount in the direction opposite to the energy irradiation side can be obtained. Further, since the magnetic head base material is melted at a high temperature and at a relatively high temperature, the stability after deformation is sufficient.

[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 structure of the magnetic head of the present invention. Here, a winding hole 11 for passing the head winding and a screw hole 15 for fixing the magnetic head base 14 to the cylinder.
A method of irradiating a position between and with, for example, thermal energy of a laser for adjusting the head height and adjusting the head height is assumed.
In this case, the output of the YAG laser that is the irradiation heat source is 3
The magnetic head base 14 is irradiated with a laser beam having a diameter of 00 watts and a laser beam diameter of 600 μm.

An irradiation hole 12 is provided at a position of about 3 mm to 6 mm from the tip of the magnetic head chip 10.
When this laser beam is irradiated for 1 pulse with a pulse width of 9 ms, the surface 1 to be installed on the cylinder in the height direction of the magnetic head
The height of the magnetic head changes by 1 μm in the direction opposite to 8.

Similarly, when the parallel irradiation area 13 is irradiated, in this case, the surface 1 to be installed on the cylinder in the opposite direction to that described above.
On the 8 side, the magnetic head height changes by 1 μm. From this, by processing the magnetic head base 14, it is possible to obtain the displacement in the vertical direction of the magnetic head height even by laser irradiation from one direction.

The irradiation hole depth 16 which is the depth of the irradiation hole 12 on the magnetic head base 14 is the magnetic head base thickness 17
By making the depth more than half, the laser energy is applied to the thickness difference portion between the magnetic head base thickness 17 and the irradiation hole depth 16. The larger the thickness difference portion is, the larger the displacement amount can be obtained, but it is remarkable when the irradiation hole depth 16 is more than half of the magnetic head base thickness 17. Although this portion is subjected to the action of heat contraction, the surface 18 which is installed in the cylinder around the irradiation hole 12 does not receive energy from the laser and is not displaced by the force of heat contraction. Undergoes displacement in the direction opposite to the surface 18 installed on the cylinder. After all, when the irradiation hole 12 is irradiated, it is displaced in the direction opposite to the irradiation side. Further, when the parallel irradiation area 13 on the magnetic head base 14 is irradiated, only the irradiated surface receives energy, and therefore the displacement is only in the irradiation direction.

If the height of the magnetic head is adjusted by using the thermal energy of the laser, even if the irradiation amount is accidentally exceeded and the target irradiation displacement amount is exceeded, the irradiation position of the magnetic head base is changed to change the magnetic position. It is possible to return the excess of the head height adjustment amount by laser irradiation from the same direction. The head height can be adjusted by synchronizing the rotation of the head on the fluid bearing rotary cylinder and irradiating the laser to adjust the magnetic head height while rotating. Also, if the laser energy is increased, one pulse can be adjusted in units of a few milliseconds for one pulse per head, and the head height can be adjusted in a short time. Fine adjustment can be easily performed by simply reducing the amount, and high-precision adjustment is possible.

In the head height adjusted by using the energy of the laser as described above, the displacement amount does not change due to the influence of mechanical vibration or environmental change.

This magnetic head base can also be provided by forming a plurality of irradiation holes in a base having a plurality of magnetic head chip mounting portions on one magnetic head base such as a multi-head. is there. Also in this case, the head height adjustment time can be shortened or the irradiation energy can be small.

In the present embodiment, welding deformation by irradiation of laser light using light energy was used, but in principle, any method can be used as long as local heating can be performed. Examples include arc welding using electron energy, electron beam welding, ultrasonic welding using ultrasonic energy, and gas welding using chemical energy.

[0021]

As described in the above embodiments, according to the present invention, a plurality of magnetic head chips are combined into a single magnetic head base without performing final adjustment in a cylinder state and selection of the magnetic head chips. The position of the magnetic head chip can be adjusted with high accuracy when mounted on the.

Further, even in the case of heat irradiation from one direction, when the displacement in the height direction of the magnetic head is applied to the hole formed on the magnetic head, the displacement in the direction opposite to the irradiation side is obtained, and the part other than the hole is irradiated. Then, since the displacement can be obtained on the irradiation side, it is possible to adjust later even if the target displacement amount is exceeded. In addition to reducing the number of parts in the manufacturing process of the current VTR, rationalizing the adjustment work, and improving the yield of the head, it is possible to mass-produce VTRs with higher image quality in addition to the cost reduction merits.

[Brief description of drawings]

1A is a front view of a magnetic head according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of a magnetic head according to an embodiment of the present invention.

FIG. 2A is a partially cutaway cross-sectional view for explaining a state of a head installed by a conventional magnetic head base with an insect screw. FIG. 2B is a head by a conventional magnetic head base with a pushing force of an insect screw. Partially enlarged view for explaining the height adjustment

3A is a front view of a conventional magnetic head having a uniform thickness, and FIG. 3B is a cross-sectional view of a conventional magnetic head having a uniform thickness.

[Explanation of symbols]

 10 Magnetic Head Chip 11 Winding Hole 12 Irradiation Hole 13 Parallel Irradiation Area 14 Magnetic Head Base 15 Screw Hole 16 Irradiation Hole Depth 17 Magnetic Head Base Thickness 18 Surface Mounted on Cylinder 21 Cylinder 22 Magnetic Head Base 23 Magnetic Head Chip 24 Installation Screw 25 Bug screw 27 Force direction of bug screw 28 Magnetic head chip height

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Toinchi, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-1-102715 (JP, A) JP-A-4 -195813 (JP, A)

Claims (2)

[Claims] 1. The height of the magnetic head is provided by providing a recessed portion in a part of the magnetic head base near the magnetic head chip and irradiating the recessed portion with light rays or heat to obtain displacement in the height direction of the magnetic head. A magnetic head characterized by being adjusted. 2. The magnetic head according to claim 1, wherein the depth of the recessed portion of the magnetic head base is not less than half the thickness of the main surface of the magnetic head base.