JPH07105025B2 - Magnetic head positioning device - 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 positioning apparatus used for manufacturing a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus, the improvement of the recording density is a time lapse, and the added value of higher performance and smaller size is produced. As the elemental technology, it is important to improve the performance of the tape and the head as an elemental component, and more importantly, to secure the relative positional accuracy at the time of recording of the tape and the head. That is, the track position accuracy in narrow track recording is that.

A conventional technique for a home VTR will be described. In the VHS system, the track pitch is 58 microns in the 2-hour recording specification, and the track pitch is 19 microns in the 6-hour recording specification.

The accuracy of the track pitch is determined by the relative positional accuracy (head height) of the two pairs of video heads mounted on the rotary cylinder and located 180 degrees apart. At present, a manufacturing method is adopted in which the head base is mechanically deformed by a screw embedded in a rotary cylinder to which the head is attached so that the magnetic head comes to a predetermined position.

On the other hand, as a technique for bending a plate material, there is bending of the plate material due to thermal deformation which is seen in welding deformation other than mechanical deformation (for example, Sato's work, Welding Optical Science & Engineering Co., Ltd. publication), and its laser source There is a technique for laser bending using the above (for example, JP-A-2-93028).

[0006]

When mechanically deformed by a screw embedded in a rotary cylinder, a positioning error occurs due to loosening of the screw, and it is difficult to secure the positioning accuracy on the order of submicrons in consideration of the change over time. Met.

The thermal deformation caused by welding deformation is almost permanent deformation and is satisfactory in terms of reliability, but the strain itself is affected by the initial strain state of the material, and is required as a head positioning accuracy. There was a problem that the accuracy on the order of micron could not be achieved.

[0008]

In the magnetic head of the present invention,
The positioning device is a magnetic cylinder with one end fixed to a rotating cylinder.
As a head positioning device, it is provided on a rotating cylinder.
The through hole, and heat a part of the head base through it.
It is composed of a laser light source to be deformed, a measuring unit for measuring the amount of deformation, and a feedback control unit for controlling the energy and irradiation position of the laser light source to be irradiated based on the measured value.

[0009]

The light energy emitted from the laser light source is applied to the head base, and the heat energy causes the head base to be thermally deformed.

The amount of deformation of the head at that time is measured by the measuring unit, and the amount of deformation from the initial value is measured. By calculating the amount of deformation with respect to the energy of the added laser light, the deformation to the final target head position is performed. The head positioning can be controlled in the sub-micron order by feeding back the laser energy required for the amount and the irradiation position.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed description will be given by taking as an example the positioning of a video head mounted on a rotary cylinder.

In FIG. 1, reference numeral 1 denotes a rotary cylinder, on which a video head fixed by a head mounting screw 9 is mounted. As a video head, a head chip 4 is attached to the tip of a head base 3.

In order to set the position of the head chip 4 at a desired position, the rotary cylinder 1 is provided with a laser beam through hole 8 for irradiating a laser beam, and a laser beam is radiated from the laser light source unit 5 through this hole to make the head. The base 3 is deformed by welding.

The position of the head chip 4 before and after the irradiation of the laser light is measured by a head chip position measuring unit 6 which is an optical microscope. This measured value is sent to the feedback control unit 7 and the relation between the variable measurement and the laser energy for each irradiation is calculated.

Based on the result of this calculation, the power of the laser light source unit 5 is controlled or the laser irradiation position is moved to irradiate the laser again. The result is measured again by the measuring unit 6, and by repeating these, the head chip 4 can be positioned with sub-micron accuracy.

As for the irradiation of the laser light to the head base 3, a position 11 between the head chip 4 and the head fixing surface 13 is suitable as shown in FIG. 2, and the pulsed laser light 10 is applied to the laser irradiation position 11. A large deformation amount 12 was obtained when irradiation was performed with high energy, and the deformation amount could be increased even with the same laser power by shifting the laser irradiation position for each pulse. However, when the same energy was applied to the same place, the amount of deformation increased only slightly.

This means that welding deformation correlates with the volume of the heat-melted portion, and the amount of deformation can be controlled by the laser power or irradiation area.

The head chip 4 is deformed in parallel to the head fixing surface 13 when the laser irradiation position 11 is uniformly irradiated to the head base 3, or when the head base 3 is irradiated uniformly. In the first place, it is usually made of metal such as brass, there is an internal strain due to punching, and the amount of deformation by a constant laser beam is not constant.

Therefore, the laser energy and the amount of deformation could not be uniquely determined. For this reason, when positioning in the degree of configuration or in order to deform the head base 3 in parallel to the head fixing surface 13, it is necessary to make the laser irradiation positions slightly nonuniform and deform so as to cancel the internal strain. , Feedback controller 7 for feeding back the amount of deformation
is necessary.

This feedback control unit is necessary in order to intentionally control the attitude (azimuth) of the head chip 4 or to perform positioning with sub-micron accuracy, and this feedback control unit is required. It is necessary to repeat the cycle of controlling the laser power and determining the irradiation position and repeating this cycle.

As described above, in order to position the head by using the thermal deformation of the head base by the laser beam, the measuring unit for measuring the amount of deformation and the power of the laser beam to be irradiated next by calculating the measured value. By using a configuration in which a feedback control unit that determines the irradiation position and the laser light source are combined, it is possible to perform highly accurate submicron positioning.

Although a laser light source is used as a heat source for causing thermal deformation from the gist of the present invention, a pulse laser is suitable from the viewpoint of energy of thermal melting.

The heat source is not limited to the laser light source,
It is also possible to collect a white light source such as a halogen lamp,
Electron beam focusing and the like are also applicable to the present invention.

[0024]

As described above, when the magnetic head positioning device according to the present invention is used, the positioning of the magnetic head can be controlled on the order of submicrons, and the recording density of the magnetic recording / reproducing device is dramatically improved. You can

[Brief description of drawings]

FIG. 1 is a configuration diagram of a head positioning device according to the present invention.

FIG. 2 is a perspective view for explaining a laser irradiation unit.

[Explanation of symbols]

 1 rotating cylinder 3 head base 4 head chip 5 laser light source section 6 measuring section 7 feedback control section

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Noriaki Maekawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-58-88873 (JP, A) JP-A-1- 227279 (JP, A) JP 63-303237 (JP, A) JP 62-36725 (JP, A)

Claims (1)

[Claims] 1. A magnet fixed to a rotating portion of a rotating cylinder.
For the air head, a through hole is provided in a part of the rotary cylinder.
And thermally deform a part of the head through the through hole.
A magnetic head positioning device comprising a laser light source, a measuring unit that measures the amount of deformation of the laser light source, and a feedback control unit that controls the energy and irradiation position of the laser light source that irradiates based on the measured value.