JPH0963024A - Positioning device for magnetic head and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a magnetic head positioning with high reliability and with high accuracy by rotating the rotary optical system of a laser beam while making the degree of revolution and a phase synchronized by a rotary synchronization control part a rotating rotary cylinder. SOLUTION: The laser beam 8 emitted from a laser oscillator 7 is bent at right angle on a total reflection mirror 9 and at this time, the optical axis of the laser beam 8 is made so as to be on the same straight line as the rotary axis of a rotary cylinder 1. The bent laser beam 8 is once deflected to the outer side (the left side in the figure) on a next total reflection mirror 10. Moreover the beam is deflected at right angle on another one sheet of a total reflection mirror 11 so as to become parallel with the original laser beam 8 to be made incident on a condensing optical system 12. Thus, the magnetic head positioning having high reliability, high accuracy and also of high efficiency is performed.

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 in the manufacture of a magnetic recording / reproducing apparatus and a positioning method thereof.

[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.

For example, in a VTR for home use, two pairs of magnetic heads, which are attached to the outer periphery of a rotary cylinder so as to face each other by 180 °, sequentially scan the magnetic tape obliquely while recording image and audio information. Playing. In fact, V
In the HS 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.
m. Furthermore, in order to improve the recording density, improve the image quality, and record for a long time, a narrow track pitch (5 to 1
5 μm) is being studied.

The track pitch accuracy is determined by the positioning accuracy of the two pairs of magnetic heads. Among these precisions, the relative height precision of two pairs of magnetic heads, 18
There are 0 ° indexing accuracy and absolute height accuracy of each magnetic head. Among these, the relative height accuracy of the two pairs of magnetic heads is
Most affected track pitch accuracy. That is,
In order to improve the track pitch accuracy, it is necessary to increase the relative height accuracy of the two pairs of magnetic heads mounted on the rotary cylinder, as described above.

Normally, the cylinder unit of a VTR is mainly a rotating cylinder (upper cylinder) as shown in FIG.
1, a fixed cylinder (lower cylinder) 2 and a magnetic head. Further, the magnetic head is mainly composed of a head chip 3 and a head base 4, as shown in FIG. The head chip 3 is adhered to the tip of the head base 4, and is fixed to the rotary cylinder 1 by a head base mounting screw 5 via the head base 4.

Here, the height of the magnetic head means (FIG. 4).
3, the distance (H) between the reference surface at the lower end of the fixed cylinder 2 and the gap end of the head chip 3 of the magnetic head fixed to the rotary cylinder 1 is shown. A conventional magnetic head height adjusting method will be described with reference to FIG.

In the rotary cylinder 1 to which the magnetic head is attached, the insect screw 6 is embedded above the center of the head base 4 to which the head chip 3 is adhered. The insect screw 6 is screwed downward to the head base 4 by a necessary adjustment amount. That is, the head base 4
Is partially elastically deformed downward by the insect screw 6, and the height of the magnetic head is adjusted by trial and error.

On the other hand, by arc welding, laser irradiation, etc.,
It has long been known that heat deformation occurs when heat is applied to a material. Conventionally, a measure to minimize the thermal deformation that occurs when these heat sources are added to a material has been studied (for example, welding engineering, Kunihiko Sato, edited by Rikagakusha,
Issued in 1979). On the other hand, it is proposed that the thermal deformation (plastic deformation) when a laser beam is used as a heat source is positively used and applied to the bending of a plate material (for example,
JP-A-62-93028).

However, in these techniques, the plate material is largely deformed macroscopically by using a laser beam. On the contrary, a method of processing (adjusting) the plate material by laser irradiation with high precision in the submicron unit is hardly studied.

Therefore, according to the present invention, the head base 4 to which the head chip 3 is adhered is irradiated with a laser beam and melted to plastically deform the head base 4,
A method of positioning (adjusting) the height of the magnetic head is proposed.

Further, the present invention synchronizes with the head base 4 mounted on the rotating cylinder 1,
Since the laser irradiation is performed locally, the height of the magnetic head can be positioned with higher accuracy.

[0012]

The basic method of adjusting the height of a magnetic head using a conventional insect screw is based on the pushing force of the insect screw within the limit range of the elastic deformation of the head base.
The point is that the partial elastic deformation of the head base is used. Therefore, if the pushing amount of the insect screw changes due to mechanical vibration or temperature change, the deformation amount of the head base changes correspondingly, and eventually the height of the magnetic head changes.

Actual VTR has various causes of vibration such as cylinder rotation, tape running, and external vibration, and the temperature generated by the heat generated from these drive systems and the change of operating environment. Change is inevitable.

At present, an insect screw loosening preventive agent, which is a screw lock, is used for insect screws in an attempt to minimize the influence from these fluctuation factors. The height of the magnetic head had changed.

On the other hand, when two head chips are attached to one head base like a combination head base, there is another problem. In the conventional insect screw adjustment method, the elastic deformation of the head base when adjusting the height of one magnetic head interferes with the height of the remaining magnetic heads, and changes that height. It was very difficult to adjust the height of both magnetic heads.

Recently, in high performance VTRs, fluid bearings are often used as bearings for rotating cylinders. This type of rotating cylinder is a dynamic pressure generated by the rotation of the shaft,
Since the structure supports the shaft, when the rotating cylinder rotates, the upper cylinder floats, and when the rotation stops, the floating upper cylinder descends and the upper cylinder tilts without reproducibility. Therefore, the relative height of the two pairs of magnetic heads of the rotary cylinder is as follows if the rotary cylinder is not rotating.
Its exact height cannot be measured.

Therefore, in the conventional insect screw adjusting method, first, the rotary cylinder is rotated to measure the heights of the two pairs of magnetic heads, and then, when the heights are adjusted,
The rotating cylinder had to be stopped and done with insect screws. Furthermore, the height of the adjusted magnetic head is
It was necessary to rotate the rotary cylinder again and measure the height of the magnetic head to see if it was adjusted correctly. Since the height of the magnetic head is adjusted when the rotary cylinder is in a stationary state, the height of the magnetic head was inspected in a rotating state, and it was often found that the height was not sufficiently adjusted. Therefore, after the inspection, for the cylinder that is not adjusted sufficiently, the rotation measurement and the stationary adjustment are repeatedly performed as described above until the height accuracy is achieved. in this way,
With the conventional insect screw adjusting method, it is very difficult to adjust the height of the magnetic head in units of submicrons.

An object of the present invention is to solve the above-mentioned problems, to obtain high reliability with strong resistance to mechanical vibration and temperature change, with high accuracy and efficiency, and for a rotating cylinder as well as a magnetic head. A positioning device for a magnetic head that can perform positioning, and a positioning method for the same.

[0019]

In order to solve the above-mentioned problems, a magnetic head positioning apparatus according to the present invention comprises a laser oscillator, a focusing optical system for focusing a laser beam emitted from the laser oscillator, and a focusing optical system. A magnetic head comprising: a rotation mechanism section for rotating an optical optical system; a rotation control section thereof; and a rotation synchronization control section for synchronizing the rotation of the rotary cylinder and the rotation of the condensing optical system. It is a positioning device.

Further, the positioning method is such that a laser beam emitted from a laser oscillator is made incident on a condensing optical system which is synchronously rotating with the rotating cylinder, and the laser beam condensed by this condensing optical system is further made. Is applied to the head base of a rotating rotary cylinder to deform the head base to position the magnetic head.

[0021]

According to the present invention, the condensing optical system for condensing the laser beam emitted from the laser oscillator while the rotating cylinder is rotating is also controlled by the rotation synchronization control section. Rotates in synchronization with. Therefore, the laser beam emitted from the focusing optical system can be synchronously focused and irradiated onto a desired position of the head base of the rotating cylinder.

The head base is plastically deformed by laser irradiation, and the tip of the head base to which the head chip is attached changes in the height direction. By appropriately controlling the amount of deformation, the magnetic head can be positioned with high accuracy. Further, since the head base is plastically deformed, the amount of deformation is strong against mechanical vibration and temperature change, and high reliability is obtained.

As described above, according to the present invention, the magnetic head can be positioned with high reliability, high accuracy and high efficiency.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, an example of a cylinder unit of a VTR will be described below with reference to the drawings.

A concrete device configuration and its operation will be briefly described with reference to the embodiments of the first and second inventions (FIG. 1).

Laser beam 8 emitted from laser oscillator 7
Is bent at a right angle (downward in the drawing) by the total reflection mirror 9. At this time, the optical axis of the laser beam 8 is made coaxial (colinear) with the rotation axis of the rotary cylinder 1. The bent laser beam 8 is deflected once outside (left side in the drawing) by the next total reflection mirror 10. Further, it is deflected at a right angle by another total reflection mirror 11 so as to become a beam parallel to the original laser beam 8 and is incident on the condensing optical system 12. Further, the laser beam 8 emitted from the laser oscillator 7 may be incident on the optical system using an optical fiber (not shown) or the like.

Usually, in the VHS type (stationary type) of the VTR, the diameter of the rotary cylinder 1 is 62 mm and the number of rotations is 1800 rpm, so the peripheral speed is about 5.
8 m / s. That is, one rotation is made in about 33 ms.
Normally, the irradiation time (pulse width) of the laser beam 8 used for processing is 1 to 20 ms in the case of Nd: YAG laser.
It is.

Consider a case where the laser beam 8 is radiated to the rotating rotary cylinder 1 while the laser beam 8 is fixed without being rotated. From the relationship between the peripheral speed of the rotating cylinder 1 and the irradiation time of the laser beam 8,
The rotating cylinder 1 rotates about 1/30 to 1/3 of the circumference within the time when the laser beam 8 is irradiated. This means that the laser irradiation position moves in the rotation direction accordingly. Therefore, in order to irradiate the desired position of the head base 4 of the rotating cylinder 1 with the laser beam 8 without causing displacement, the laser beam 8
Also, it is necessary to rotate the rotary cylinder 1 synchronously and set its relative speed to zero.

The above-mentioned optical system (total reflection mirrors 10 and 11 and condensing optical system 12) includes a motor 1 which is a rotation mechanism section.
3 is attached. At this time, the rotation axis of this optical system and the optical axis of the laser beam 8 incident on this optical system are installed on the same straight line. The rotation of the motor 13 is controlled by the motor rotation controller 14. Thereafter, the optical system including the motor 13 is replaced with the rotating optical system 15
I will call it. Condensing optical system 1 of this rotating optical system 15
The focal point of the laser beam 8 exiting 2 makes a rotational scanning movement on a circle having a certain radius r on a certain plane.

The cylinder unit is installed below the rotary optical system 15, and the rotary cylinder 1 is provided with a laser irradiation window 16 for passing the laser beam 8. The cylinder unit is a rotating optical system 1
The upper surface of the head base 4 attached to the rotary cylinder 1 is aligned with the plane on which the laser beam 8 emitted from the laser beam 8 is focused, and the rotary optical axis of the laser beam 8 for rotary scanning and the rotary axis of the rotary cylinder 1 are Positioned so that they are on the same straight line. Further, the laser beam 8 which is rotationally scanned is irradiated to the outside from the rotational optical axis by a distance r. That is, the laser beam 8 is focused on the upper surface of the head base 4 attached to the rotary cylinder 1 at a position separated from the rotation axis of the rotary cylinder 1 by a distance r.

Further, the motor rotation control unit 14 of the rotary optical system 15 and the cylinder rotation control unit 17 of the rotary cylinder 1 are controlled in synchronization in rotation speed and phase by a rotation synchronization control unit 18 having a delay circuit. There is. That is,
The rotary optical system 15 and the rotary cylinder 1 are synchronously rotated at a substantially constant speed, and their phases (rotation angles) are substantially matched. In this embodiment, the speed / phase of the rotary optical system 15 is matched with the speed / phase of the rotary cylinder 1. When observing the rotary cylinder 1 from the rotary optical system 15, the rotary cylinder 1 is almost stationary. Further, the Del included in the rotation synchronization control unit 18
These phases can be adjusted to arbitrary positions by the ay circuit.

When the rotary cylinder 1 and the rotary optical system 15 are stably rotating, and the rotary cylinder 1 and the rotary optical system 15 are synchronized (speed / phase), the laser oscillator 7 outputs The emitted laser beam 8 is rotated by the rotating optical system 15.
And is focused on the upper surface of the head base 4 attached to the rotary cylinder 1. At this time, the delay circuit of the rotation synchronization control unit 18 needs to match the phase of the rotary optical system 15 to a desired position of the head base 4 of the rotary cylinder 1.

In this embodiment, the rotational speed of the rotary cylinder 1 is the rotational speed used when actually recording / reproducing the rotary cylinder 1. However, the number of rotations may be reduced as long as the rotation performance of the rotary cylinder 1 (height of each magnetic head, inclination of the shaft, etc.) is not significantly affected (for example, 1/10 to 1). / 2).

Next, the behavior when the laser beam 8 is irradiated onto the upper surface of the head base 4 through the laser irradiation window 16 will be described with reference to the enlarged view of FIG. (Fig. 2)
It is an enlarged view of the laser irradiation part vicinity of the rotating cylinder 1.

The head base 4 is locally and rapidly heated by the focused laser beam 8. Therefore, a sharp temperature gradient is generated in the vicinity of where the laser beam 8 is focused.

When the laser beam 8 is being irradiated, the temperature of the upper surface of the head base 4 rises and the thermal expansion thereof causes the head base 4 to bend with the irradiation direction of the laser beam 8 outward (see FIG. a)). At this time, a large compressive stress acts on the upper surface of the head base 4, and when the compressive stress exceeds the yield point of the material, the upper surface of the head base 4 shifts from elastic deformation to plastic deformation. Further, the yield point has a close relationship with the temperature of the material, and generally, the yield point tends to decrease as the temperature rises.

When the intensity of the laser beam 8 is very weak,
Since the compressive stress does not exceed the yield point of the material, the head base 4 is elastically deformed, and when the irradiation of the laser beam 8 is completed, the deformation is restored to the original state.

When the intensity of the laser beam 8 increases, the compressive stress exceeds the yield point of the material, so that part of the deformation of the head base 4 becomes plastic deformation. Even if the irradiation of the laser beam 8 is completed, the plastic deformation remains, so during natural cooling, the head base 4 is plastically deformed accordingly.
It is bent with the irradiation direction of the laser beam 8 inward (FIG. 3B).

When the intensity of the laser beam 8 is further increased, the head base 4 is locally melted, and the head base 4 is largely plastically deformed by the compressive stress at the time of solidification by natural cooling, and the irradiation direction of the laser beam 8 is increased. Can be bent greatly with the inside.

As described above, the height of the magnetic head can be adjusted by utilizing the plastic deformation of the head base 4 by the laser irradiation. The amount of plastic deformation depends on the energy of the laser beam 8, the pulse width, the irradiation position on the head base 4, the number of irradiations, and the like.

As a specific example, the relationship between the energy P (J / P) of the laser beam 8 applied to the head base 4 and the plastic deformation amount ε of the head base 4 (converted into the amount of displacement at the tip of the head chip 3). Is shown in the graph of FIG. 5 (the pulse width is fixed at 5 ms). From this graph, for example, the magnetic head can be displaced by 12 μm by irradiating the head base 4 with the laser beam 8 at an energy of 5 J / P. Conversely, a certain magnetic head is 6 μm
When it is desired to displace, the head base 4 may be irradiated with the laser beam 8 at an energy of 2.5 J / P.

Further, even if the heat shock test is repeated for 10 hours by repeating -40 ° C. and 80 ° C., the amount of deformation only changes within 0.1 μm, which is an extremely reliable adjusting method.

Further, as described above, since the head base 4 of the rotating cylinder 1 can be irradiated with the laser, the height of the magnetic head in the rotating state can be adjusted.

Next, an embodiment of the third invention (FIG. 6 (a))
This will be described with reference to (d). The rotating optical system 15 has a first
In the embodiment of the invention, the total reflection mirrors 10 and 11, the condensing optical system 12, and the motor 13 are included. The rotating optical system 15 (1) deflects the incident laser beam 8 with respect to the optical axis (distance: r). (2) The incident laser beam 8 is condensed. (3) The focused laser beam 8 is rotationally scanned. It is enough if there is a function that satisfies the requirements.

FIG. 6A shows an example of a concrete structure of the rotary optical system 15. The rotating optical system 15 includes a condensing optical system 12, a deflection optical system 19, and a hollow motor 20. For example, as the deflection optical system 19, as shown in FIG.
Although the prism is described in (a)), the laser beam 8 may be deflected by using two mirrors. The condensing optical system 12 and the deflection optical system 19 are attached to the hollow shaft 21 of the hollow motor 20.

The laser beam 8 is incident on the approximate center of the hollow shaft 21 of the hollow motor 20, is condensed by the condensing optical system 12, is once deflected in the outer peripheral direction by the deflecting optical system 19, and then is deflected. The hollow shaft 21 of the hollow motor 20 is deflected substantially in the direction of the rotation axis. The laser beam 8 that has passed through the deflection optical system 19 is moved parallel to the outside by a distance r from the rotation axis of the hollow shaft 21 of the hollow motor 20. This distance r
Is determined by the shape of the deflection optical system 19 (prism).

As described above, the hollow shaft 21 of the hollow motor 20
Condensing optical system 12 and deflecting optical system 19 attached to
Is rotated together with the hollow shaft 21 by the motor rotation control unit 14, so that the laser beam 8 can be rotationally scanned and focused.

In FIG. 6 (a), the condensing optical system 12 is attached above the deflection optical system 19 (see FIG. 6).
As shown in (b)), the condensing optical system 12 is replaced with the deflecting optical system 1.
It may be attached below 9. In addition, the condensing optical system 12
Need not necessarily be attached to the hollow shaft 21 of the hollow motor 20, but may be installed above the hollow shaft 21 of the hollow motor 20 as shown in FIG. 6C.

On the other hand, in order to reduce the number of parts and downsize,
As shown in FIG. 6D, a deflecting / converging optical system 22 (for example, a decentering lens) in which the converging optical system 12 and the deflecting optical system 19 are integrated may be used.

Next, an embodiment of the fourth invention will be described with reference to FIG. In the following description, the same parts as in FIG. 1 will be omitted as much as possible.

The first to third inventions described above are methods of adjusting the height of the magnetic head by using the laser beam 8. In fact, before adjusting the height of the magnetic head, it is necessary to accurately measure the height of the magnetic head in advance. With this function added,
It is the fourth invention.

In the magnetic head mounted on the rotary cylinder 1, the head main surface observing optical system for observing the main surface of the magnetic head in contact with the medium (eg, magnetic tape) is the lens barrel 2.
3, an objective lens 24, a CCD camera 25, and a TV monitor 26. An illumination light source 27 that emits light in synchronization with the rotary cylinder 1 is attached to the lens barrel 23. For example, a strobe light source having a short pulse width, a pulsed dye laser such as an N ₂ / Dye laser, or the like is used as the illumination light source 27. A synchronization signal generation unit 28 having a delay circuit is added to the cylinder rotation control unit 17 of the rotary cylinder 1, and the illumination light source 27 emits light based on the synchronization signal generated from the synchronization signal generation unit 28. . For example, a PG signal, which is a control signal for the cylinder, an FG signal, or the like is used as the synchronization signal.

The light emitted from the illumination light source 27 is reflected by the half mirror 29 in the lens barrel 23 and applied to the main surface of the magnetic head. The reflected light from the main surface of the magnetic head is magnified by the objective lens 24 and focused on the CCD camera 25. CC
The head position measuring device 30 is used to measure the height of the magnetic head from the image data obtained from the D camera 25.
As the head position measuring device 30, a measuring method by image recognition is often used, but separately, the height of the magnetic head may be measured by aligning the cursor line of the TV monitor 26 with the gap end of the magnetic head. .

As described above, the head main surface observing optical system,
By adding the illumination light source 27 and the head position measuring device 30, the height of the rotating magnetic head can be measured with high accuracy and the height of the magnetic head can be adjusted with high accuracy.

Illumination light source 27 for irradiating the main surface of the magnetic head
At present, the position of the light emission timing with respect to the rotation direction (phase) of the main surface of the magnetic head is not constant. This is due to a mounting error of the magnetic head, a difference in magnetic characteristics of the magnetic head, and the like. Therefore, if the magnetic head or the cylinder unit changes, the position (rotational direction) of the main surface of the magnetic head observed on the TV monitor 26 also moves. When it gets worse, the main surface of the magnetic head may move to a position where it cannot be observed by the monitor 26 even when the illumination light source 24 emits light.

When the head position measuring device 30 is used to measure the height of the magnetic head from the image data of the main surface of the magnetic head observed on the TV monitor 26, the magnetic head main unit is placed at the approximate center of the TV monitor 26. It is desirable that the surface comes, and in that case, the measurement accuracy is highest.

In order to realize this, the position (rotation direction) of the main surface of the magnetic head measured by the head position measuring device 30 is
The timing of the synchronous light emission of the illumination light source 27 is transmitted so that the magnetic head main surface can be observed at the approximate center of the head main surface observation optical system based on this value (head position). To control. This is performed by the delay circuit of the synchronization signal generator 28. Further, when the main surface of the magnetic head is not displayed on the TV monitor 23, the main surface of the magnetic head is searched for by greatly shifting the timing of the synchronized light emission of the illumination light source 27 for irradiation.

By performing the method as described above, the height of the rotating magnetic head can be measured stably and highly accurately.

Next, an embodiment of the fifth invention will be described with reference to FIG. The configuration of the present invention (FIG. 8) is a configuration in which a central processing unit (CPU) 31 is added to the configuration of the fourth invention (FIG. 7). In the following description (Fig. 7)
Omit the same points as

The central processing unit (CPU) 31 (1) laser oscillation control (ON-OFF of laser oscillation, output energy, pulse width) (2) selection of the head base 4 to be adjusted in the cylinder 1 (3 ) Laser irradiation position control (irradiation position control on the head base 4) (4) Magnetic head height measurement timing control (5) Basic displacement data bank (correlation between laser irradiation condition and magnetic head height displacement amount) Relations) (6) Calculation of laser irradiation conditions (irradiation position, output energy, pulse width) (7) Functions such as judgment of adjustment success / failure.

The method of adjusting the height of the magnetic head by the central processing unit (CPU) 31 proceeds according to the following procedure.

(1) Initial head height measurement of desired magnetic head (by head position measuring device 30) (2) Calculation of required adjustment amount of desired magnetic head (3) Calculation of laser irradiation conditions from required adjustment amount (4) ) Laser irradiation condition setting, laser irradiation positioning (5) Laser irradiation (6) Head height measurement of desired magnetic head after laser irradiation (7) Judgment of pass / fail is performed in order, and the desired magnetic head is moved to a desired position. Until the time comes, the work from (2) to (7) is repeated automatically.

Next, an example of adjusting the height of the magnetic head will be specifically described. Also, for the sake of clarity, we will use the simplest possible example.

The number of magnetic heads mounted on the rotary cylinder 1 is two (Rch, Lch), and the relative height accuracy (target value) is ± 0.5 μm.

(1) Initial measurement result: Rch = 0 μm, L
ch = 5.3 μm (Rch reference relative position) (Lch is 5.3 μm higher than Rch) (2) Calculation of required adjustment amount: Lch: Reference head Rch: 5.3 μm adjustment required ( 3) Calculation of laser conditions: Energy: 2.2 J / P: Pulse width: 5 ms (from FIG. 5) (Expected displacement: 5.28 μ)
m) (4) Laser condition setting (2.2 J, 5 ms), laser irradiation positioning (Rch) (5) Laser irradiation (6) Inspection measurement result: Rch = 0.4 μm, Lch = 0
μm (reference head) (7) Judgment result: adjustment completed (Rch-Lch = 0.4 μm)
m <0.5 μm) As described above, based on the position of the magnetic head measured by the head position measuring device 30, the laser irradiation condition of the laser beam 8 with which the head base 4 is irradiated, the laser irradiation position, and the like are calculated,
In addition, a central processing unit (CP) that performs laser oscillation control, selection of the adjustment head base 4, measurement timing control, and the like, and performs feedback control until the final target adjustment accuracy is reached.
By adding (U) 31, the height of the magnetic head can be automatically adjusted with higher accuracy and in a shorter time.

Next, an embodiment of the sixth invention will be described with reference to FIG. 9 (FIG. 9). In FIG. 9, only the points which are the key points of the present invention are described.

The external magnetic field generator comprises a magnetic field yoke 32,
It is composed of a magnetic field generator 33, and the magnetic field yoke 32 is
It is arranged near the magnetic head attached to the rotary cylinder 1 as shown in FIG. For example, as the magnetic field yoke 32, a bar-shaped soft magnetic ferrite having a sharp tip and a winding is often used. It is also possible to use the magnetic head itself as the magnetic field yoke 32. When a current (AC or DC) is applied to this winding from the magnetic field generator 33, a magnetic field is formed at the tip of the magnetic field yoke 27.

When the rotary cylinder 1 is rotated and the magnetic head attached to the rotary cylinder 1 crosses this magnetic field, a magnetic head reproduction output signal is generated from this magnetic head.

The synchronizing signal generator 34 amplifies, filters, and differentiates the magnetic head reproduction output signal,
A synchronization signal is generated according to the position of the magnetic head attached to the rotary cylinder 1.

Conventionally, the synchronizing signal for the rotary cylinder 1 is a PG signal which is a control signal for the rotary cylinder 1 or an FG signal.
I was using the signal. The synchronization signals based on these signals maintain the synchronization accuracy, but have no correlation with the position of the magnetic head attached to the rotary cylinder 1. Therefore, during mass production, when synchronizing the phases of the rotary optical system 15 and the rotary cylinder 1, or when observing the main surface of the magnetic head,
Since the position of the magnetic head attached to the rotary cylinder 1 is not stable between the individual cylinder units, it is difficult to adjust the phase of the synchronization accuracy to a desired phase position.

Therefore, as described above, the rotary cylinder 1
The above problem can be solved by using a synchronization signal generated by the synchronization signal generator 34 according to the position of the magnetic head attached to the rotary cylinder 1 as the synchronization signal for the.

Next, an embodiment of the seventh invention will be described with reference to FIG. Also in FIG. 10, only the points that are the key points of the present invention are described.

The head base observation optical system for observing the head base 4 mounted on the rotary cylinder 1 from the laser irradiation surface side is a lens barrel 35, a CCD camera 36, and a TV monitor 3.
7. Furthermore, a light source 38 for illumination that emits light in synchronization with the rotary cylinder 1 is attached to the lens barrel 35. As the illumination light source 38, for example, a strobe light source having a short pulse width, a pulsed dye laser such as an N ₂ / Dye laser, or the like is used. The lens barrel 35 contains a dichroic mirror 39, a half mirror 40, and an imaging lens 41. The dichroic mirror 39 is a mirror capable of totally reflecting the laser beam 8 (usually 99% or more) and almost transmitting visible light (usually 90% or more).

The light emitted from the illumination light source 38 is reflected by the half mirror 40 in the lens barrel 35, and is irradiated onto the head base 4 through the rotary optical system 15. The light reflected from the head base 4 is imaged on the CCD camera 36 by the imaging lens 41. Since the illumination light source 38 emits light synchronously with the rotating cylinder 1, the position of the rotating head base 4 can be observed and confirmed on the TV monitor 37.

On the other hand, the magnetic head has its head base 4
The positioning between the head chip 3 and the head chip 3 is not assembled with high accuracy. Further, the rotary cylinder 1 and the rotary optical system 15 are connected to each other by the PG signal of the rotary cylinder 1 and the FG signal.
The signal or the reproduction output signal from the magnetic head is controlled as a reference. Therefore, the irradiation position of the laser beam 8 is based on the position of the head chip 3 of the magnetic head. On the other hand, the displacement amount of the height of the magnetic head when the laser beam 8 is irradiated on the head base 4 depends on the irradiation position on the head base 4. That is, when the laser beam 8 is applied, it is better to use the reference of the head base 4.

Therefore, on the basis of the position (rotational direction) of the head base 4 obtained by the head base observation optical system, the rotary cylinder 1 and the rotary optical system 1 are arranged so that the laser beam 8 can be irradiated to a desired position of the head base 4. If the synchronous adjustment (Delay adjustment) with the system 15 is performed, a more stable displacement can be obtained.

[0077]

As is apparent from the above embodiments, according to the present invention, the rotation optical system of the laser beam also controls the rotation speed / phase of the rotating rotation cylinder by the rotation synchronization control unit. Rotate in synchronization. Therefore, the laser beam emitted from the laser oscillator can be synchronously focused and irradiated onto a desired position on the head base of the rotating cylinder.

The head base is plastically deformed by laser irradiation, and by appropriately controlling the amount of plastic deformation, the magnetic head can be positioned with high accuracy. Further, since the head base is plastically deformed, the amount of deformation is strong against mechanical vibration and temperature change, and high reliability is obtained.

As described above, according to the present invention, it is possible to perform the positioning of the magnetic head with high reliability, high accuracy and high efficiency.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a magnetic head positioning device in an embodiment of the first and second inventions.

[Fig. 2] Enlarged view of laser irradiation part

FIG. 3 is an explanatory diagram of the behavior of the head base during laser beam irradiation.

FIG. 4 is an explanatory diagram of a conventional magnetic head positioning method.

FIG. 5 is a diagram showing a correlation between energy of a laser beam and an amount of plastic deformation.

FIG. 6 is a configuration diagram of a magnetic head positioning device according to an embodiment of the third invention.

FIG. 7 is a configuration diagram of a magnetic head positioning device according to an embodiment of the fourth invention.

FIG. 8 is a configuration diagram of a magnetic head positioning device according to an embodiment of the fifth invention.

FIG. 9 is a configuration diagram of a magnetic head positioning device according to an embodiment of the sixth invention.

FIG. 10 is a configuration diagram of a magnetic head positioning device according to an embodiment of the seventh invention.

[Explanation of symbols]

 1 rotating cylinder (upper cylinder) 2 fixed cylinder (lower cylinder) 3 head chip 4 head base 5 head base mounting screw 6 insect screw 7 laser oscillator 8 laser beam 9, 10, 11 total reflection mirror 12 condensing optical system 13 rotation mechanism Part (motor) 14 Motor rotation control unit 15 Rotation optical system 16 Laser irradiation window 17 Cylinder rotation control unit 18 Rotation synchronization control unit 19 Deflection optical system (prism) 20 Hollow motor 21 Hollow shaft 22 Deflection focusing optical system 23 Lens barrel 24 Objective lens 25 CCD camera 26 TV monitor 27 Illumination light source 28 Sync signal generator 29 Half mirror 30 Head position measuring device 31 Central processing unit (CPU) 32 Magnetic field yoke 33 Magnetic field generator 34 Synchronous signal generator 35 Lens tube 36 CCD Camera 37 TV monitor 38 Light source for lighting 9 dichroic mirror 40 a half mirror 41 imaging lens

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masateru Doi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Tatsuo Nagasaki, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Emi Kagami 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A magnetic recording / reproducing apparatus having a rotating cylinder on which a magnetic head is mounted, a laser oscillator, a focusing optical system for focusing a laser beam emitted from the laser oscillator, and rotating the focusing optical system. A magnetic head positioning device comprising: a rotation mechanism section; a rotation control section thereof; and a rotation synchronization control section for synchronizing the rotation of the rotary cylinder and the rotation of the focusing optical system. 2. A condensing optical system for condensing a laser beam emitted from a laser oscillator, and a deflection optical system for deflecting the laser beam to a head base as a rotation mechanism section for rotating the condensing optical system, 2. The magnetic head positioning device according to claim 1, wherein the condensing optical system and the deflection optical system are constituted by a hollow motor having a hollow shaft attached thereto. 3. In a magnetic head mounted on a rotary cylinder, a head main surface observing optical system for observing a magnetic head main surface in contact with a medium, and synchronous light emission to the rotary cylinder to irradiate the magnetic head main surface. 2. The magnetic head positioning device according to claim 1, further comprising a head position measuring device for measuring the position of the magnetic head based on an illumination light source and image data obtained by the head main surface observation optical system. 4. A rotating cylinder equipped with a magnetic head,
An external magnetic field generator for applying an external magnetic field, and a sync signal generator for generating a sync signal from a magnetic head reproduction output when the magnetic head crosses the external magnetic field are added. Head positioning device. 5. A head base observation optical system for observing a head base to which a head chip is attached from a laser irradiation surface side, and an illumination light source for emitting light synchronously to the rotating cylinder to irradiate the head base surface. The magnetic head positioning device according to claim 1, wherein: 6. A magnetic recording / reproducing apparatus having a rotating cylinder on which a magnetic head is mounted, wherein a laser beam emitted from a laser oscillator is made incident on a converging optical system which is synchronously rotating with the rotating cylinder, and the laser beam is further collected. A method of positioning a magnetic head, comprising irradiating a head base of a rotating rotary cylinder with a laser beam condensed by an optical optical system, deforming the head base, and positioning the magnetic head. 7. A head main surface observation optical system for observing a main surface of a magnetic head in contact with a medium in a magnetic head mounted on a rotary cylinder;
An illumination light source for irradiating the main surface of the magnetic head and image data obtained by the optical system for observing the main surface of the head, while irradiating the head base while measuring the magnetic head position obtained using a head position measuring device. The magnetic head positioning method according to claim 6, wherein the magnetic head is positioned by controlling the laser irradiation conditions, the number of times of irradiation, and the irradiation position of the laser beam.