JP2000020931A - Positioning method for magnetic head and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To practically position a magnetic head with high precision by irradiating with light, and moreover, to prevent interferences from occurring between the irradiated light and a rotary cylinder. SOLUTION: While a rotary cylinder 2 with a magnetic head 1 mounted thereon is rotated, the magnetic head 1 is positioned by being displaced toward a target position by having a specified position 5 of the magnetic head 1 irradiated with light 6 from an optical system 4 rotating in synchronization with the rotary cylinder on the same rotary axis 3 and thermally deforming the position. Then, the irradiation of the light 6 to the specified position of the magnetic head 1 from the optical system 4 is performed via a straight-advancing light path 8 tilted to be directed to the near position from the far position around the rotary axis 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for positioning a magnetic head of a magnetic recording / reproducing device for video equipment and a device therefor.

[0002]

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

For example, in a home VTR, a magnetic head mounted 180 degrees opposite to the outer periphery of a rotary cylinder records image and audio information while sequentially scanning the magnetic tape in an oblique direction. To play again. Specifically, in the case of the VHS system, the track pitch recorded on the magnetic tape is 58 μm in the 2-hour mode and 19 μm in the 6-hour mode. Furthermore, the track pitch is becoming very narrow in the digital video standard. It is 10 μm in the standard mode and 7 μm in the LP mode.

The track pitch accuracy is determined by the relative height accuracy of the two pairs of magnetic heads. This accuracy includes relative height accuracy of two pairs of magnetic heads, 18
There are 0 degree indexing accuracy, absolute height accuracy of each magnetic head, and the like. In particular, the relative height accuracy of the two pairs of magnetic heads most affects the track pitch accuracy. That is, in order to improve the track pitch accuracy, it is necessary to increase the accuracy of the relative height in addition to the absolute height of the magnetic head mounted on the rotary cylinder as described above.

As shown in FIG. 4, a cylinder unit of a VHS type VTR generally includes a rotary cylinder (upper cylinder) a, a fixed cylinder (lower cylinder) b, and a rotary cylinder a. It is composed of a pair of magnetic heads c. As shown in FIG. 4, the magnetic head c mainly includes a head chip c1 and a head base c2 that supports the head chip c1. The head chip c1 is adhered to the tip of the head base c2, and is fixed to the rotating cylinder a via the head base c2 by attaching the head base c2 to the rotating cylinder a with the screw d.
Here, the height of the magnetic head c is, as shown in FIG.
From the reference surface c3 at the lower end of the fixed cylinder b to the head chip c
1 is the distance h from the gap end.

The conventional method of adjusting the height of a magnetic head c shown in FIG. 4 is based on a rotary cylinder a to which the magnetic head c is mounted, above a center portion of a head base c2 which adheres and holds a head chip c1. The screw e is screwed from below. The screw screw e pushes the head base c2 downward against its spring force in accordance with the amount of protrusion from the rotary cylinder a.
By rotating the head base c2 from above to adjust the amount of downward projection from the rotary cylinder a, it is possible to change the depressed position of the head base c2 and adjust the height of the head chip c1.

[0007] On the other hand, it has been well known for a long time that heat is applied to a material by arc welding or laser welding to cause a heat change, and it has been studied and applied to minimize the amount of thermal deformation as much as possible. In some cases, bending of a sheet material is performed by positively utilizing thermal deformation caused by laser beam irradiation (Japanese Patent Application Laid-Open No. Sho 62-93028).

In recent years, there has been proposed a method of adjusting the height of a magnetic head by thermal deformation when irradiating a laser beam and positioning the magnetic head (Japanese Patent Application Laid-Open No. 04-195,813).
JP-A-09-63024, etc.).

These components have a basic structure as shown in FIG. 4 and are provided in place of the screw e in a portion of the rotary cylinder a corresponding to a predetermined position of the magnetic head c as shown in FIG. A hole g is provided, and a laser beam j is applied to a predetermined position of the head base c2 through the through hole g.

In the head base c2, a portion where the laser beam j is focused and irradiated is locally and rapidly heated. Therefore, a sharp temperature rise occurs near the laser beam j being condensed, and the expansion causes the head base c2 to be bent with the irradiation side of the laser beam j out as shown in FIG. At this time, a large compressive force acts on the upper surface of the head base c2, and when the compressive force exceeds the yield point of the material, the upper surface of the head base c2 shifts from elastic deformation to plastic deformation. Further, the yield point has a close relationship with the temperature of the material, and generally, as the temperature increases, the yield point tends to decrease.

When the intensity of the laser beam j is very low, the compressive stress does not exceed the yield point of the material, so that the head base c2 is elastically deformed. Is restored.

When the intensity of the laser beam j increases, the compressive stress exceeds the yield point of the material, so that part of the deformation of the head base c2 becomes plastic deformation. Even if the irradiation of the laser beam j is completed, the plastic deformation remains, so that the head base c2 is plastically deformed by that amount during natural cooling, and the irradiation direction of the laser beam j is set to the inside as shown in FIG. Bend.

When the intensity of the laser beam j is further increased, the head base c2 is locally melted, and the head base c2 is largely plastically deformed by the compressive stress at the time of solidification by natural cooling, and the irradiation direction of the laser beam j is increased. The inside can be bent greatly.

As described above, the height adjustment and positioning of the magnetic head c can be performed by utilizing the difference in the degree of plastic deformation according to the degree of irradiation of the laser beam j from the head base c2. The amount of plastic deformation can be controlled by controlling the irradiation energy of the laser beam j, the driving pulse width of the laser beam j, the irradiation position on the head base c2, the number of irradiations, the irradiation time, and the like.

[0015]

The above-mentioned conventional apparatus measures the current height position from a reference position in a state where the rotary cylinder is stopped, and, based on the measurement result, measures the current height position on the stopped rotary cylinder. The magnetic head is moved or displaced toward the target height position. However, in many cases, even if recording and reproduction are actually performed by the magnetic recording and reproducing apparatus whose height has been adjusted, preferable results cannot be obtained.
Therefore, after the positioning operation, the positioning result is determined by trial and error such that the positioning result is determined by using a test, and if the positioning operation is not possible, the positioning is performed again.

In this connection, the present inventors have conducted various experiments and studied repeatedly, and found that the height position of the magnetic head when the rotary cylinder was actually rotated to perform recording and reproduction stopped. It was found that the reason was that the height position did not match the height position of the rotating cylinder. In particular, in a magnetic recording / reproducing apparatus in which a rotating cylinder employs a fluid bearing that supports the rotating shaft with dynamic pressure generated by rotation of the rotating shaft,
The height position of the magnetic head is greatly different between the stopped state and the used state of the rotary cylinder.

Further, the conventional apparatus shown in FIG. 5 irradiates the laser beam j to the head base c2 of the magnetic head c from directly above, that is, from the direction parallel to the rotation axis k of the rotary cylinder a. For this reason, as shown in FIG.
When the height of the laser beam increases, the rotating cylinder a and the laser beam j
Causes the problem of interference. For example, the bearing portion of the rotary cylinder a may be lengthened to achieve stable rotation, or the rotary cylinder a
When a rotary transformer is mounted on the rotary cylinder a, the height of the rotary cylinder a increases, and the laser beam j and the rotary cylinder a interfere with each other at a portion a1 shaded black in FIG. Irradiation energy for a predetermined position of the head base c2 decreases, height adjustment and positioning become unstable, and a portion of the rotary cylinder a that interferes with the laser beam j is damaged or deteriorated by thermal energy of the laser beam j. There is a problem to do.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic head positioning method and a magnetic head positioning method in which the positioning of a magnetic head can be accurately performed in accordance with actual light irradiation, and there is no problem of interference between irradiation light and a rotary cylinder. Is to provide.

[0019]

In order to achieve the above object, a method of positioning a magnetic head according to the present invention comprises rotating a rotary cylinder on which a magnetic head is mounted while simultaneously rotating the rotary cylinder on the same rotation axis. One characteristic is that the magnetic head is displaced toward a target position and positioned by irradiating a predetermined position of the magnetic head with light from a rotating optical system and thermally deforming that portion.

As described above, by rotating the rotary cylinder for positioning the magnetic head, the measurement of the position of the magnetic head and the target position based on the measurement can be properly obtained in the pseudo use state. In addition, the magnetic head of the rotating cylinder that is rotated is irradiated with light from an optical system that rotates synchronously with the rotating cylinder, thereby stopping the magnetic head at a predetermined position on the rotating cylinder in the pseudo use state without relative movement. The necessary time without displacement as in the case of matching ones can be continuously irradiated with light, so that the magnetic head is thermally deformed as set based on the appropriate measurement information without the influence of rotation, Positioning can be accurately performed at an appropriate target position.

Further, in the magnetic head positioning method according to the present invention, the light irradiation from the optical system to a predetermined position of the magnetic head is performed along an inclined straight optical path from a position far from the rotation axis to a position close to the rotation axis. Is also one of the features.

With this arrangement, the final straight optical path for irradiating the magnetic head with light has a position from the rotation axis of the rotary cylinder to a predetermined position where the magnetic head irradiates light is set as the closest position to the rotation axis, and the upstream side is rotated. It is inclined with respect to the rotation axis so as to move away from the axis, so that it is advantageous to irradiate light with an optical system that rotates synchronously with the rotation cylinder on this rotation axis. Even if the light coming from the head is once directed in the direction away from the rotation axis, and then is made to enter the final straight light path, by setting the length of the straight light path appropriately, the size of the rotary cylinder above the magnetic head mounting position can be increased. No matter what setting is made, interference with the optical path can be prevented, and positioning using thermal deformation due to light irradiation can be stably achieved without loss of light energy Is to, such as a rotating cylinder is avoided as is denature or damage interferes with light irradiated.

As described above, the light to be applied to the predetermined position of the magnetic head is made incident on the rotation axis, directed once in a direction away from the rotation axis, and then made incident on the straight optical path. The downstream irradiation-side optical system including an optical element arranged to direct incident light in a direction away from the rotation axis needs to be rotated around the rotation axis, but the light source-side optics that causes light to enter the optical element. The system only needs to be incident on the axis of rotation, and does not need to be rotated. This reduces the rotational load on the optical system, thereby reducing the size and improving the reliability.

The position of the magnetic head on the rotating rotary cylinder from the reference position is measured by image recognition, and a target position for positioning the magnetic head is set based on the measurement information. The position of the magnetic head can be accurately measured in a non-contact manner, and the target position of the magnetic head set based on the position can be set appropriately.

According to the magnetic head positioning apparatus of the present invention, a rotary cylinder on which a magnetic head of a magnetic recording / reproducing apparatus is mounted corresponds to a predetermined position where the rotary cylinder is rotated for positioning.
An optical system for guiding and irradiating light to a predetermined position of the magnetic head,
A rotation mechanism for rotating the optical system on the rotation axis of the rotation cylinder, and a rotation synchronization controller for controlling the rotation of the rotation cylinder and the rotation of the optical system to be synchronized, the optical system is provided around the rotation axis. One feature is that light is emitted to a predetermined position of the magnetic head along a straight optical path that is inclined from a distant position to a close position.

According to this, the positioning method of the magnetic head by irradiating light while the rotating cylinder and the optical system are synchronously rotated by an appropriate related operation of each component, and a straight traveling optical path inclined with respect to the rotation axis. The method for positioning the magnetic head for irradiating the magnetic head with light is automatically and stably achieved according to a predetermined program.

If the light incident from the rotation axis is once directed by a prism in a direction away from the rotation axis, the light is incident on the optical path and is irradiated on a predetermined position of the magnetic head. Since bending can be performed with one optical element, the number of parts and the number of assembly steps are reduced,
Since the relationship between the positions and orientations of the two reflecting surfaces is mechanically set at the stage of manufacturing the prism, the step of setting the mutual positions and orientations when a human is assembling the two total reflection mirrors becomes unnecessary. Manufacturing cost can be reduced and reliability can be improved.

[0028] Further objects and features of the present invention will become apparent from the following detailed description and the accompanying drawings. Each feature of the present invention can be used alone or combined in various combinations as much as possible.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic head positioning method and apparatus according to a representative embodiment of the present invention will be described below with reference to FIGS. Serve for understanding.

This embodiment is an example of the case where the magnetic head of the VHS type magnetic recording / reproducing apparatus is positioned.
Therefore, the cylinder unit of the magnetic recording / reproducing apparatus 11 of each embodiment shown in FIGS. 1 and 2 has the rotating cylinder 2 disposed on the fixed cylinder 21 and the outer periphery 18 on the lower surface of the rotating cylinder 2.
The magnetic head 1 is fixed at the 0-degree position, and the rotating cylinder 2 is rotated at a predetermined speed by a motor (not shown) mounted on the fixed cylinder 21 so that the magnetic tape running on the outer circumference of the fixed cylinder 21 and the rotating cylinder 2 can be moved. Thus, magnetic recording and reproduction are performed through the magnetic head 1.

However, the present invention is not limited to this, and the present invention can be similarly applied to a magnetic head of any magnetic recording / reproducing apparatus having a similar problem.

The magnetic head positioning method according to the present embodiment is performed by rotating the rotary cylinder 2 on which the magnetic head 1 is mounted with reference to the positioning device 12 of each embodiment shown in FIGS. A predetermined position 5 of the magnetic head 1 is irradiated with light 6 from an optical system 4 that rotates synchronously on the same rotation axis 3 as above to thermally deform the portion, thereby displacing the magnetic head 1 toward a target position for positioning. . The irradiation of the light 6 from the optical system 4 to the predetermined position 5 of the magnetic head 1 is performed along an inclined straight optical path 8 which is directed from a far position around the rotation axis 3 to a near position.

The light 6 irradiates a very small predetermined position 5 of the magnetic head 1, preferably a straight light in terms of irradiation efficiency, and is preferably a laser beam having a large thermal energy for thermal deformation. . However, the present invention is not limited to this, and any light may be used as long as the object is achieved. The predetermined position 5 of the magnetic head 1 can be set to any position as long as the magnetic head 1 can be positioned by applying a partial thermal deformation, in particular, a portion for performing recording and reproduction of the magnetic head 1 can be positioned.

As described above, the magnetic head 1 is of a conventional type in which a head chip 1a for recording and reproducing is provided at the tip of a head base 1b attached to a rotary cylinder 2 by screws 16 or the like as shown in the figure. Thus, an appropriate position in the longitudinal direction of the head base 1b may be selected. As the position is set closer to the tip of the head base 1b, the final straight light path 8 of the light 6 reaching the predetermined position 5 becomes farther from the rotation axis 3 of the rotary cylinder 2, so that the light 6 and the rotary cylinder 2 This is advantageous for preventing interference. However, there is a disadvantage that the closer to the head base 1b, the smaller the amount of displacement of the head chip 1a with respect to the degree of bending of the head base 1b. These points and the head base 1b
It may be appropriately set in consideration of the bending characteristics with respect to the irradiation of the light 6 such as the material and thickness of the material.

In order to realize the above-described positioning method, the positioning device 12 for the magnetic head 1 according to the present embodiment, as shown in FIGS.
A light 6 is guided to a predetermined position 5 of the magnetic head 1 and radiated corresponding to a predetermined position where the rotary cylinder 2 equipped with the magnetic head 1 is rotated for positioning, in one embodiment, a predetermined position on the positioning device 12. And a rotation mechanism 1 for rotating the optical system 4 on the rotation axis 3 of the rotary cylinder 2.
3 and a rotation synchronization controller 14 for controlling the rotation of the rotary cylinder 2 and the rotation of the optical system 4 so as to be synchronized with each other. The light 6 is applied to a predetermined position 5 of the magnetic head 1 on the optical path 8.
Is irradiated.

Further, on the positioning device 12, a measuring instrument 114 for measuring the height position of the magnetic head 1 above the rotating cylinder 2 by the recognition camera 113 and measuring the height position by image recognition is also provided. The height position of the magnetic head 1 is
As described above, the lower surface 21a of the fixed cylinder 21 is used as a reference position, and the gap end between the head base 1b attached to the rotary cylinder 2 with screws or the like from this reference position and the head chip 1a attached to the tip thereof by bonding or the like. Since the relative height of the pair of magnetic heads 1 mounted on the rotary cylinder 2 at a position of 180 degrees is important, the distance H is measured. When the measured height position of the magnetic head 1 is inappropriate, for example, the displacement amount from the measured position to the desired height position, that is, the correction amount is set as the target position, and the rotation cylinder 2 The above-described positioning operation is performed so that the height position of the rotating magnetic head 1 becomes the target position.

In the embodiment shown in FIG. 1, the optical system 4 directs the laser beam 6 emitted from the laser oscillator 122 onto the rotation axis 3 by a total reflection mirror 23 on the rotation axis 3, and directs the laser beam 6 to a magnetic head. It has a light source side optical system 4b that is incident on an irradiation side optical system 4a for irradiating the predetermined position 5. The irradiation-side optical system 4a directs the laser beam 6 incident on the rotation axis 3 in a direction away from the rotation axis 3 at a right angle, for example, by a total reflection mirror 25 on the rotation axis 3, and then moves the magnetic head 1 from the rotation axis 3. At a position separated from the rotation axis 3 by a distance Y2 larger than the distance Y1 to the predetermined position 5,
An inclined final straight optical path 8 that is reflected by one total reflection mirror 25a toward the predetermined position 5 of the magnetic head 1 is formed. A condensing lens 32 for condensing the laser beam 6 at a predetermined position 5 of the magnetic head 1, that is, for forming an image, is provided in the middle of the straight traveling optical path 8.

The condenser lens 32 may be provided at any position, and two or more condenser lenses may be provided at various positions. Further, the light source side optical system 4b receives the laser light 6 from the laser oscillator 122.
Can be made to enter the total reflection mirror 25 of the irradiation side optical system 4a on the rotation axis 3 by an optical fiber or the like.
The point is that the light 3 only needs to be incident on the irradiation-side optical system 4a from the rotation axis 3;

The rotation mechanism 13 is, for example, a positioning device 12
The optical system 4 is rotatably driven on the rotation axis 3 by a drive motor 27 directly connected to a support 26 which supports the optical system 4 so that the optical system 4 can be rotated.
Circuit, and a rotation control unit 28 of the drive motor 27.
And the rotation control unit 29 of the drive motor (not shown) of the rotary cylinder 2 provided in the fixed cylinder 21 so that the rotary cylinder 2 and the optical system 4 are synchronously rotated. That is, the rotating cylinder 2 and the optical system 4
Basically, they are synchronously rotated at a substantially constant speed, and their phases (absolute rotation angles) also substantially match. Thus, the optical system 4
, The rotary cylinder 2 becomes almost stationary. Further, the rotation synchronization controller 14 can adjust the phase of the optical system 4 and the rotation cylinder 2 to an arbitrary position by the delay circuit.

Here, the rotating cylinder 2 and the optical system 4 are rotating stably, and the rotating cylinder 2 and the optical system 4
Is synchronized (speed, phase) with the laser light 6 emitted from the laser oscillator 122 through the optical system 4,
The light is focused on a predetermined position 5 of the magnetic head 1 on the rotating cylinder 2. At this time, it is necessary for the rotation synchronization controller 14 to control the phase of the optical system 4 by a delay circuit so that the phase is adjusted to a desired position of the head base 1b of the rotary cylinder 2.

A target position is set based on the measurement result from the measuring device 114, and the light irradiation time or / and the emission intensity of the laser beam 6 for accurately displacing the height position of the magnetic head 1 to the target position are set. As can be obtained, the laser oscillator 1
A positioning control unit 31 for controlling the operation of the rotation control unit 22 and / or the rotation control units 28 and 29 is provided.

As described above, by rotating the rotary cylinder 2 for positioning the magnetic head 1, the measurement of the position of the magnetic head 1 and the target position based on the measurement can be properly obtained in the pseudo use state. Therefore, a fluid bearing is employed in which the rotating shaft 2a of the rotating cylinder 2 is supported by dynamic pressure due to its rotation, and the height position from the reference position of the magnetic head 1 differs greatly between the stopped state and the rotating use state. This is particularly suitable when such a situation occurs.

The magnetic head 1 of the rotating cylinder 2 which is rotated is irradiated with laser light 6 from an optical system 4 which rotates synchronously with the rotating cylinder 2 so that the magnetic head 1 on the rotating cylinder 2 in the simulated use state is irradiated. 1 can be continuously irradiated with light for a required period of time without any positional displacement, as in the case of stationary objects having no relative movement, so that the magnetic head 1 is not affected by rotation and the proper measurement information Is thermally deformed as set on the basis of the above, and can be accurately positioned at the appropriate target position. Therefore, it is free from the conventional trial and error positioning operation, and highly accurate positioning can be automatically and stably achieved in a short time by the device according to a predetermined program.

A laser beam 6 for irradiating a predetermined position 5 of the magnetic head 1 is incident on the rotation axis 3 and once directed in a direction away from the rotation axis 3, and is then inclined with respect to the rotation axis 3. The irradiation side optical system on the downstream side including the total reflection mirror 25 which is an optical element disposed on the rotation axis 3 and directing the incident laser beam 6 in a direction away from the rotation axis 3 by being incident on the rectilinear light path 8. Although the light source 4a needs to be rotated about the rotation axis 3, the light source side optical system 4b for making the laser light 6 incident on the total reflection mirror 25 needs to be rotated only by making the laser light 6 incident on the rotation axis 3. However, this can reduce the size of the optical system 4 by reducing the rotational load of the optical system 4 and improve the reliability.

Further, the final straight light path 8 for irradiating the laser beam 6 to the predetermined position 5 of the magnetic head 1 has a distance Y1 from the rotation axis 3 of the rotary cylinder 2 to the predetermined position 5 for irradiating the magnetic head 1 with light. Is the closest position to the rotation axis 3, and the upstream side is inclined with respect to the rotation axis 3 so as to be further away from the rotation axis 3 to the position of the distance Y2. With rotating cylinder 2
In order to realize light irradiation by the optical system 4 that rotates synchronously with the optical axis 4 under advantageous conditions, the laser light 6 incident on the rotation axis 3 is once directed in a direction away from the rotation axis 3, and then the final Even when the light is incident on the rectilinear light path 8, by setting the optical path length of the rectilinear light path 8 as appropriate, the size of the rotary cylinder 2 from the lower surface position where the magnetic head 1 is mounted can be set in any manner. Including the configuration shown in FIG.
Can be prevented from interfering with each other. This allows
Positioning utilizing thermal deformation due to light irradiation is stably achieved without loss of light energy, and it is possible to prevent the rotary cylinder 2 or the like from being damaged or deteriorated by interfering with the irradiated laser beam 6. You. In this case, the rotating cylinder 2
Is not a part that exhibits a special function, so that it can be designed in any shape, for example, formed in a low part that does not interfere with the laser beam 6.

Incidentally, in the embodiment shown in FIG.
The laser light 6 incident from above is once directed in a direction away from the rotation axis 3 by the first reflection surface 41a of the prism 41, and then is incident on the straight light path 8 by the second reflection surface 41b, so that the magnetic head 1 is different from the embodiment of FIG. Although some of the drawings are omitted, other configurations are not particularly changed.

In this way, the laser beam 7 incident from the axis of rotation 3 can be bent twice so as to be incident on the predetermined position 5 of the magnetic head 1 by one optical element composed of the prism 41. Therefore, the number of parts and the number of assembling steps are reduced, and the relationship between the positions and orientations of the two reflecting surfaces 41a and 41b is mechanically set at the stage of manufacturing the prism 41. Since the setting process of the mutual position and the orientation as described above is not required, the manufacturing cost can be reduced and the reliability can be improved.

More specifically, the total reflection mirror 25 and the first reflection surface 41a of the prism 41 are set at 45 degrees with respect to the rotation axis 3, but the present invention is not limited to this. In order to adjust the irradiation position of the laser beam 6 to the predetermined position 5 of the magnetic head 1, the reflection surface of the total reflection mirror 25 or the first reflection surface 41 a of the prism 41 is moved to one point on the rotation axis 3. It can be easily done by rotating the center and changing the angle.

VHS type of normal VTR (stationary type)
Then, the diameter of the rotating cylinder 2 is 62 mm and the number of rotations is 18
00 rpm. Therefore, the peripheral speed is about 5.8 m / s.

That is, one rotation is performed in about 33 ms. Normal,
The irradiation time (pulse width) of the laser beam used for processing is
In the case of the Nd: YAG laser, it is 1 to 10 ms.

Now, let us consider a case where the laser beam 6 is irradiated onto the rotating cylinder 2 at a fixed timing without rotating the laser beam 6 without rotating. Considering the peripheral speed of the rotating cylinder 2 and the laser beam 6 Of the laser light 6
During the irradiation time, the rotary cylinder 2
It rotates 0 to 1/3 turns. This means that the irradiation position of the laser beam 6 moves in the rotation direction accordingly. For this reason, the laser beam 6 can be applied to the predetermined position 5 of the head base 1b of the rotating rotary cylinder 2 without causing any displacement.
In order to keep irradiating, the laser beam 6 also needs to be rotated synchronously with respect to the rotary cylinder 2 as described above to make the relative speed of each other zero.

In the embodiment, the pseudo use state is obtained by using the number of revolutions used when actually recording and reproducing the rotating cylinder 2 as the number of revolutions of the rotating cylinder 2. However, the rotation speed may be reduced as long as the rotation accuracy of the rotation cylinder 2 (the height of each magnetic head 1, the inclination of the rotation shaft 2a, etc.) is not significantly affected. For example, a range of 1/2 to 1/10 can be considered.

The data of the embodiment is as follows.
The relationship between the energy P (J / P) of the laser beam 6 applied to the head base 1 and the amount of plastic deformation ε of the head base 1b (converted to the amount of displacement at the tip of the head chip 1a) is as shown in the graph of FIG. (The pulse width is fixed at 5 ms). From this graph, it can be seen that, for example, when the laser beam 6 is irradiated on the head base 1b at an energy of 5 J / P, the head chip 1a of the magnetic head 1 is displaced by 12 μm. vice versa,
When it is desired to displace a certain magnetic head 1 by 6 μm, the laser beam 6 may be applied to the head base 1b at an energy of 2.5 J / P.

[0054]

According to the present invention, the measurement of the position of the magnetic head and the target position based on the measurement can be properly obtained in the pseudo use state by the rotation of the rotary cylinder, and the light from the optical system that rotates synchronously with the rotary cylinder can be obtained. By irradiation, the magnetic head is thermally deformed as set based on the appropriate measurement information without being affected by the rotation of the rotary cylinder, and can be accurately positioned at the appropriate target position.

Further, by a specific inclination with respect to the rotation axis of the final straight light path for irradiating the magnetic head with light, it is possible to prevent the rotation cylinder from interfering with the light path, that is, light, and to reduce thermal deformation due to light irradiation. The used positioning is stably achieved without loss of light energy, and the rotating cylinder and the like are prevented from being damaged or deteriorated by interfering with the irradiated light.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a typical embodiment of the present invention together with one example.

FIG. 2 is an overall configuration diagram showing another embodiment.

3A and 3B show a plastic deformation state of a magnetic head due to light irradiation and a relationship between them. FIG. 3A shows a magnetic head plastically deformed by light irradiation, and FIG. 4 is a graph showing the relationship between energy and the amount of plastic deformation of the magnetic head as shown in FIG.

FIG. 4 is a cross-sectional view showing a conventional magnetic head positioning device using a screw.

FIG. 5 is a cross-sectional view showing a conventional magnetic head positioning operation method by light irradiation.

FIG. 6 is a sectional view showing a state of plastic deformation in one direction by the operation of FIG. 5;

7 is a cross-sectional view showing a state of plastic deformation in the direction opposite to that of FIG. 6 by the operation of FIG. 5;

FIG. 8 is an explanatory diagram showing an interference state between irradiation light and a rotating cylinder by the operation of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic head 1a Head chip 1b Head base 2 Rotating cylinder 2a Rotating shaft 3 Rotating axis 4 Optical system 4a Irradiation side optical system 4b Light source side optical system 5 Predetermined position 6 Light 8 Straight light path 11 Magnetic recording / reproducing device 12 Positioning device 13 Rotating mechanism 14 Rotation synchronization controller 31 Positioning controller 41 Prism 41a, 41b Reflecting surface 114 Measuring device

Continued on the front page F term (reference) 4E068 AH00 CA05 CA14 CB05 CC02 CC06 CD09 CE01 DA12 5D036 AA05 AA08 AA14 AA16 CC04 CC86 GG05

Claims (9)

[Claims] 1. A rotating cylinder on which a magnetic head is mounted is rotated, and a predetermined position of the magnetic head is irradiated with light from an optical system synchronously rotating on the same rotation axis to thermally deform the portion. A method for positioning a magnetic head, wherein the positioning is performed by displacing the magnetic head toward a target position. 2. A method of positioning a magnetic head, comprising: irradiating a predetermined position of a magnetic head from an optical system with a straight light path inclined from a position far from a position around a rotation axis of the rotary cylinder to a position close to the position. Method. 3. While rotating a rotary cylinder on which a magnetic head is mounted, a predetermined position of the magnetic head is irradiated with light from an optical system that rotates synchronously on the same rotation axis to thermally deform the portion. When positioning the magnetic head by displacing the magnetic head toward the target position, light irradiation from the optical system to a predetermined position of the magnetic head is performed on a straight traveling optical path that is inclined from a position far from the rotation axis to a position close to the rotation axis. A method for positioning a magnetic head, comprising: 4. A light irradiating a predetermined position of the magnetic head,
The light is incident on the rotation axis, is directed once in a direction away from the rotation axis, and then is incident on the straight light path.
3. The method for positioning a magnetic head according to claim 3. 5. The positioning according to claim 1, wherein a target position is set based on positional information from a reference position of the magnetic head measured when the rotary cylinder is being rotated, and positioning is performed. Magnetic head positioning method. 6. An optical system which guides and irradiates a predetermined position of a magnetic head with a rotary cylinder mounting a magnetic head of a magnetic recording / reproducing apparatus corresponding to a predetermined position rotated for positioning; A rotation mechanism that rotates the optical system on the rotation axis of the rotation cylinder, and a rotation synchronization controller that controls the rotation of the rotation cylinder and the rotation of the optical system to be synchronized, the optical system is distant about the rotation axis. A magnetic head positioning device, wherein light is applied to a predetermined position of a magnetic head along an inclined straight optical path directed to a position close to the position. 7. The optical system according to claim 6, wherein the light incident from the rotation axis is directed in a direction away from the rotation axis, and then is incident on the straight light path to irradiate a predetermined position of the magnetic head. 3. The magnetic head positioning device according to claim 1. 8. The optical system according to claim 1, wherein the light incident from the rotation axis is once directed in a direction away from the rotation axis by a prism, and then is incident on the straight light path to irradiate a predetermined position of the magnetic head. Item 8. A magnetic head positioning device according to Item 7. 9. A measuring means for measuring a position of a rotating rotary cylinder from a reference position of a magnetic head by image recognition, and an optical device for displacing the magnetic head toward a target position based on positional information of the measurement result. 9. The magnetic head positioning device according to claim 6, further comprising a positioning control unit that operates the system.