JPH02206047A - Magneto-optical recorder - Google Patents

Abstract

PURPOSE:To obtain high reproducing S/N ratio by vibrating the irradiating position of laser beams on a recording medium in a direction perpendicular to a tracking direction. CONSTITUTION:The laser light for recording or erasing from a laser light source 1 through a beam shaping lens 2 and a beam splitter 3 is made incident on an acoustooptical or electrooptical deflecting element 4 in which frequency is modulated to be driven, so as to obtain the laser beams 8 whose irradiating position on the recording medium 6 is vibrated in the direction perpendicular to the tracking direction. The recording medium 6 is irradiated with the vibrated laser beams 8 through a condensing lens 5 to extend the width of the heated area on a recording medium 6 in the direction perpendicular to the tracking direction and also extend a range where the difference of the temperature distribution is small in the heated area. The laser beam spot 23 is relatively moved in the tracking direction while being vibrated with the amplitude <=about 0.3mum on a track 21 for recording in the direction perpendicular to the tracking direction. Then, recording magnetic domain 24 having a shape where round projection or angular projection is prevented from occurring in the end part of a recording magnetic domain is obtained. Thus, the occurrence of jitter at the time of detecting a signal is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magneto-optical recording device that performs recording using the heat of laser light and reproducing using the magneto-optic effect.

Conventional technology In magneto-optical recording devices, recording is carried out thermomagnetically by utilizing the local temperature rise of the recording medium caused by laser beam irradiation, and for reproduction, a weak linearly polarized laser beam is applied to the recorded area of the recording medium. This is done by irradiating the area and detecting the direction of surname change in that area using the Kerr effect or Faraday effect (magneto-optical effect).

Conventional magneto-optical recording devices have two methods for recording signals: one is to modulate the recording laser beam intensity according to the signal under a constant recording magnetic field, and the other is to modulate the recording laser beam intensity according to the signal under a constant recording magnetic field. There is a method of recording by modulating the direction of the recording magnetic field.

Problems to be Solved by the Invention However, when recording is performed using the two methods described above in a conventional magneto-optical recording device, the magnetic domain shapes formed by recording are as shown in FIGS. 4(a) and 4(b). The problem is that the magnetic domain area is small compared to the optical spot area, and a sufficient reproduced signal amplitude cannot be obtained (reproduced signal-to-noise ratio is low). In particular, in the method of recording by modulating the recording magnetic field, angular protrusions occur on the recording magnetic domain as shown in Figure 4(b), and even when the optical spot is between the recording magnetic domains, the angular protrusions do not produce light. Since it enters the spot area, when the recording wavelength is short, the reproduction signal amplitude decreases greatly. Furthermore, long angular protrusions have the problem of not only affecting the reproduced signal amplitude but also causing jitter during signal detection.

In view of the above problems, the present invention provides a high reproduction SN ratio,
In order to reduce the occurrence of jitter during signal detection, a rounded protrusion or angular protrusion (Fig. 4 (a) (b The present invention provides a magneto-optical recording device having means for forming a recording magnetic domain that suppresses the occurrence of (see ).

Means for Solving the Problems In order to solve the above problems, the magneto-optical recording device of the present invention includes:
The apparatus includes a means for vibrating the irradiation position of the laser beam on the recording medium in a direction perpendicular to the track direction during at least one of a recording operation and an erasing operation.

Effect of the Invention With the above configuration, the present invention vibrates the irradiation position of the laser beam on the recording medium in the direction perpendicular to the track direction at a sufficiently fast period compared to the relative movement speed of the recording medium with respect to the laser beam, thereby performing recording and erasing. At times, the width of the heating area on the recording medium is expanded in the direction perpendicular to the track direction, and the range where the temperature distribution difference in the heating area is small is widened. Since the generation of angular protrusions is suppressed, a high reproduction SN ratio can be obtained, and the occurrence of jitter during signal detection can also be reduced. Furthermore, during the erasing operation, the recorded magnetic domain can be completely erased.

EXAMPLE Hereinafter, a magneto-optical recording apparatus according to an example of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows the configuration of an optical system of a magneto-optical recording apparatus in an embodiment of the present invention. In Figure 1,
1 is a laser light source, 2 is a beam shaping lens, 3 is a beam splitter, and 14 is an acousto-optic deflection element such as LiNbO3 (
AO deflection element), 5 is a condensing lens, 6 is a recording medium, 7 is a photodetector, 8 is a laser beam whose irradiation position is vibrating, and 9 is a recording magnetic field generator. Recording or erasing laser light from a laser light source 1 passes through a beam shaping lens 2 and a beam splitter 3 and is incident on an AO deflection element 4 driven by frequency modulation, so that the irradiation position on the recording medium 6 is perpendicular to the track direction. A laser beam 8 that vibrates is obtained. This oscillating laser beam 8 is irradiated onto the recording medium 6 through the condensing lens 5 to widen the width of the heated area on the recording medium 6 in the direction perpendicular to the track direction, and to widen the range where the temperature distribution difference in the heated area is small. . FIGS. 2 and 3 respectively show the recorded magnetic domains on the recording medium and the vibration state of the laser beam when recording is performed using a method of modulating the recording magnetic field using a magneto-optical recording device according to an embodiment of the present invention. What is shown schematically and the temperature distribution of the heated area on the recording medium in the direction perpendicular to the track direction is compared with the temperature distribution of the heated area on the recording medium when recording is performed using a conventional magneto-optical recording device. It is.

In FIG. 2, 21 is a recording track on a recording medium;
22 is a track separating the recording tracks, 23 is a laser beam spot that moves relatively while vibrating, 24 is a recorded magnetic domain, and 25 is a direction in which the laser beam spot moves relative to each other. When the laser beam spot 23 is relatively moved in the track direction on the recording track 21 while vibrating with an amplitude of about 0.3 μm or less in the direction perpendicular to the track direction, a rounded protrusion or an angular shape at the end of the recording magnetic domain is generated. A recording magnetic domain 24 having a shape as shown in the figure in which the generation of protrusions is suppressed is obtained. As shown in Figure 3, this is due to the fact that when recording with a conventional device, the width of the heating area in the direction perpendicular to the relative track direction increases, and at the same time the range in which the difference in temperature distribution in the heating area is small (Figure 3(a)) b) A-A' range and B-B' range)
This is because it spreads.

As described above, according to this embodiment, by using the AO polarizing element to vibrate the irradiation position of the laser beam on the recording medium in the direction perpendicular to the track direction, the shape of the recording magnetic domain is improved and the reproduction SN ratio is increased. This makes it possible to reduce jitter generation during signal detection.

In this example, a magnetic field modulation recording method was used as the recording method, and an AO deflection element such as LiNb0° was used as the laser beam deflection element, but a laser light intensity modulation method was used as the recording method, and a LiTa0. An electro-optic deflection element (EO deflection element) such as , etc. may be used.

Furthermore, as is clear from its basic configuration, the present invention is applicable to optical recording other than magneto-optical recording.

Effects of the Invention As described above, the present invention provides a magneto-optical recording device having means for vibrating the irradiation position of a laser beam on a recording medium in a direction perpendicular to the track direction during at least one of a recording operation and an erasing operation. A reproduction SN ratio can be obtained, and jitter generation at the time of signal detection can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of the optical system of a magneto-optical recording device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the state in which the magneto-optical recording device according to an embodiment of the present invention is recording using the magnetic field modulation recording method. Schematic diagram of the vibration state of recording magnetic domain and laser light, Figure 3 (a)
4(b) is a graph showing the temperature distribution of the heating area in the direction perpendicular to the track direction on the recording medium in an embodiment of the present invention and in a conventional example, respectively. FIGS. FIG. 2 is an explanatory diagram showing magnetic domain shapes recorded by a light intensity modulation method and a recording magnetic field modulation method. 1-... Laser light source, 4... AO deflection element, 6... Recording medium, 8... Laser light whose irradiation position is vibrating, 9- ... Recording magnetic field generating section, 21 ... Recording track, 23 ...
- Laser light spot that moves relatively while vibrating, 24.
... Recording magnetic domain, 41 ... Recording track, 43 ... Reproduction laser beam spot, 44 ...
... Recording magnetic domain, 45 ... Recording track, 4
7...Reproduction laser light spot, 48...
・Recording magnetic domain. Name of agent: Patent attorney Shigetaka Awano 1 person? π Ward C＼ Castle number map ↑ Boundary center gift record tiger W Wage compensation direct connection center center record! Diagram of the upper device for fireflies

Claims (2)

[Claims] (1) A magneto-optical recording device characterized by comprising means for vibrating the irradiation position of a laser beam on a recording medium in a direction perpendicular to the track direction during at least one of a recording operation and an erasing operation. (2) Magneto-optical recording according to claim (1), characterized in that either an acousto-optic deflection effect element or an electro-optic deflection effect element is used as means for vibrating the irradiation position of the laser beam in a direction perpendicular to the track direction. Device.