JP2802453B2 - Method for aligning magnetic head in magnetic field modulated magneto-optical recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of aligning a position where an optical head irradiates light to a recording medium with a position where a magnetic field is applied by a magnetic head in a magnetic field modulation magneto-optical recording device. About.

2. Description of the Related Art Magneto-optical recording is a recording method in which information is recorded as magnetic domains (magnetization) on a recording medium, and the recorded information is read out using a magneto-optical effect such as a Kerr rotation angle.

Magneto-optical recording utilizes the temperature characteristics of magnetization. In recording / erasing, the temperature of a recording medium is raised by means such as laser beam irradiation. When the recording medium reaches the Curie temperature, theoretically, both the magnetization and the coercive force become zero. At this time, when an external magnetic field is applied in one direction and the temperature is lowered in this state, the magnetization and coercive force return to the original magnitudes, and the magnetization is formed in the direction of the applied magnetic field.

In magnetic field modulation magneto-optical recording, as shown in FIG. 2, the objective lens 23 of the optical head 21 and the magnetic head 11 are opposed to each other with the magneto-optical disk 51 interposed therebetween, and the light beam from the laser diode 27 is collimated. The beam is made into a parallel light beam by the lens 29, converged by the objective lens 23 through the beam splitter 31, and irradiated with a spot light on the magneto-optical disk 51 to raise the temperature. Write. At this time, it is required that the irradiation position of the spot light from the objective lens 23 and the position of the head core 13 of the magnetic head 11 exactly match.

On the other hand, in the magnetic head 11, the size of the head core 13 is made very small in order to reduce the core coil inductance to realize the high-speed magnetic field reversal. Therefore, it is difficult for the naked eye to align the light spot position with the magnetic head 11.

Therefore, conventionally, as shown in FIG. 2, the relative position between the magnetic head 11 and the light spot is moved two-dimensionally to actually perform recording, and the position where the reproduced signal is maximized is the relative optimum position between the two. Was set as Specifically, the reflected light from the magneto-optical disc 51 recorded and written as described above is polarized through the objective lens 23, the beam splitter 31, the half-wave plate 33, and the condenser lens 35. The light is guided to the beam splitter 37 and separated into P-polarized light and S-polarized light.
Detected by photodiodes 39, 39, respectively, and RF amplifier 41
And the oscilloscope 53 detects the position where the reproduced signal is maximized.

However, in this positioning method, after recording is actually performed, this is reproduced and evaluated by a reproduced signal.
At present, adjustments are intermittent and take a lot of time.

A method of adjusting the position of the magnetic head by using a separate jig such as an optical position detection device is also known, but it is necessary to devise a special shape suitable for the method, which is complicated and time-consuming. .

SUMMARY OF THE INVENTION It is an object of the present invention to facilitate alignment of a light spot irradiation position for heating a recording medium and a magnetic head for supplying a recording magnetic field in a magnetic field modulation magneto-optical recording device. .

A method of aligning a magnetic head in a magnetic field modulation magneto-optical recording device according to the present invention includes the steps of:
On the other hand, in a magnetic field modulation magneto-optical recording device that changes the direction of a magnetic field by a magnetic head based on a recording signal and applies a magnetic field to the magneto-optical recording medium to record information on the magneto-optical recording medium, light irradiation from the optical head is performed. In the method of aligning the position with the position of the magnetic head, the optical head emits light to the magnetic head in a state where a magnetic field is generated in the magnetic head, and the magneto-optical effect of the reflected light is detected. The magnetic head is positioned to the light irradiation position.

FIG. 1 is an explanatory view showing an embodiment of the present invention. The configuration of the optical head 21 is the same as that shown in FIG.

The magneto-optical recording medium utilizes a magneto-optical effect as a reproduction principle. In this method, linearly polarized light rotates its plane of polarization due to the magnetization moment of a magnetic medium. This magneto-optical effect is not limited to the magneto-optical recording medium, but is a characteristic possessed by any magnetic material.

Therefore, as shown in FIG. 1, in the high-speed magnetic field modulation magneto-optical recording device, a laser beam is spot-irradiated from the optical head 21 to the end face of the head core 13 of the magnetic head 11 in a state where the magneto-optical disk is not loaded. This can be achieved by using the lens actuator coil 25 of the optical head 21 to focus and drive the objective lens 23 to form an image of the laser beam on the end face of the core head 13. In the magneto-optical recording device, since the image forming position of the light spot on the recording disk and the end face of the head core 13 are close to each other, the spot light is generally applied to the end face of the head core 13 within the driving range of the lens actuator coil 25. it can. If the driving length of the lens actuator coil 25 is too short to form an image or the like, an auxiliary optical system can be interposed as necessary.

When the coil 15 of the magnetic head 11 is energized, an alternating magnetization Ms is generated. Saturation magnetization moment of magneto-optical recording medium is ~ 1500
Since the saturation magnetization moment of the ferrite of the core material is 2,000 to 5,000 Gauss while being about Gauss, a sufficient magneto-optical effect can be obtained even in the head core 13 using the ferrite.

Then, the polarization plane of the laser light focused and reflected on the end face of the head core 13 of the magnetic head 11 rotates by the Kerr effect. When a signal corresponding to this rotation is detected by the optical head 21 and amplified by the RF amplifier 41 and output, the alternating magnetization Ms
Is obtained.

Since the area where this detection signal appears is within the end face of the head core 13 of the magnetic head 11, the magnetic head 11 is moved two-dimensionally, and the magnetic head 11 is fixed and set at a substantially central position in this area, thereby obtaining the magnetic field. The positioning of the head 11 becomes possible. Head core 13 with objective lens 23
The light irradiation position on the recording medium is the spot light irradiation position on the recording medium during actual magneto-optical recording.
11 can be directly positioned without any position correction.

According to the present invention, the optical system and the detection system originally provided in the magneto-optical recording apparatus can be used without using a special device such as a positioning jig, and the magnetic field can be applied to the spot light irradiation position. The head can be accurately and easily positioned and set.

Therefore, since the size of the magnetic head can be reduced, the inductance is reduced accordingly, the frequency characteristics of the magnetic head are improved, and it is possible to use the magnetic head in a higher frequency range, so that higher density recording can be realized. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a magnetic head positioning method of the present invention. FIG. 2 is an explanatory diagram showing a conventional alignment method. 11 ... magnetic head, 13 ... head core 15 ... coil, 21 ... optical head 23 ... objective lens 25 ... lens actuator coil 27 ... laser diode, 29 ... collimator lens 31 ... beam splitter, 33 ... … 1/2 wavelength plate 35… Condenser lens 37… Polarization beam splitter 39 …… Photodiode, 41… RF amplifier 51… Magneto-optical disk, 53… Oscilloscope

Claims (1)

(57) [Claims] An optical head irradiates a magneto-optical recording medium with light, and a magnetic field is applied to the magneto-optical recording medium by changing the direction of the magnetic field based on a recording signal. In a method of aligning a light irradiation position from an optical head with a magnetic head position in a magnetic field modulation magneto-optical recording device for recording information on a medium, the optical head emits light from the optical head to the magnetic head in a state where a magnetic field is generated in the magnetic head. A magnetic head in a magnetic field modulation magneto-optical recording apparatus, wherein the magnetic head is positioned at a position irradiated with light from the optical head by detecting the magneto-optical effect of the reflected light. .