JPH04167244A - Recording, reproducing and erasing method for magneto-optical recording medium and apparatus for the same - Google Patents

Abstract

PURPOSE:To curtail the time required for a series of recording operation including erasing, recording, recognition and reproducing operation by inverting bias magnetic field only immediately before the recording operation and immediately after starting the recognition and reproducing operation and by always applying the magnetic field in the erasing direction during the reproducing operation. CONSTITUTION:In a series of recording operations for sequentially realizing erasing, recording, recognizing and reproducing operations stored in a controller 1 to control the magneto-optical drive, a means 2 for detecting the end of erasing process during a series of the recording operations, a means 3 for detecting the end of the recording process, a bias magnetic field control means 4 for quickly inversing the bias magnetic field depending on respective detecting operations and a bias magnetic field applying means 5 are provided. The magnetic field is inversed when the erasing process during a series of recording operations is completed and when the recording process during a series of recording operations is completed. As a result, the magnetic field in the same direction is always applied during the erasing and reproducing operations to immediately execute the erasing operation without inversion of magnetic field. Thereby, the time required for the recording can be curtailed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording/reproducing apparatus for a magneto-optical recording medium used for recording information.

Conventional technology Although the technology of magneto-optical recording has made remarkable progress in recent years, and some of them have begun to be put into practical use, issues such as stability over repeated use have not been sufficiently studied, and issues remain.

Below, we will explain an example of the conventional magneto-optical recording and reproducing device mentioned above. The bias magnetic field applying means has a function of reversing the polarity by using a bias magnetic field, a drive system for moving them and the magneto-optical recording medium relatively, and a circuit system for controlling them or processing signals. When recording with this magneto-optical recording/reproducing device, it is performed by irradiating a light beam that is pulse-modulated according to the recording signal under a constant applied magnetic field. This is done by irradiating a light beam at a constant intensity under an applied magnetic field of opposite polarity.

Problems to be Solved by the Invention However, the above configuration had the following problems.In other words, in a normal magneto-optical recording/reproducing device, it is necessary to reverse the direction of the bias magnetic field during recording and erasing. Am
This bias magnetic field can be easily created using an electromagnet, but the power consumption is extremely large.
By the way, in order to simplify the drive system of the bias magnetic field applying means, two-point driving is desirable, and one of the methods is to apply a bias magnetic field during reproduction and recording. In this method, the bias magnetic field must be reversed during the recording operation, which consists of the erasing process and the recording process, before the recording operation can start, that is, before the erasing process begins. It takes a long time from receiving a recording start command to completing recording.

In view of the above-mentioned problems, the present invention provides a magneto-optical recording/reproducing device using a permanent magnet as a bias magnetic field applying means, which enables two-point drive of a bias magnetic field corresponding to two modes: alignment, erasure, and only. To provide a magneto-optical recording/reproducing device which reduces the recording time by reversing the bias magnetic field only once during the recording operation. The magneto-optical recording/reproducing device of the invention is a device that applies a magnetic field in the same direction as during erasing during reproduction. C-dai
If the transition metal is rich at room temperature, the coercive force is 14) (oe
It is desirable that the coercive force is above 1 OK, and in the case of rare earth rich, it is desirable that the coercive force is 1 OKoe or more.
This is to suppress the phenomenon in which the magnetic domain wall of a domain gradually moves when it is repeatedly reproduced in the presence of an erasing magnetic field. Recording L Renumbering is performed by a series of operations called playback to confirm the recording. At this time, the magnetic field is reversed before recording. When a magnetic field is always applied in the erasing direction, the erasing operation can be started immediately without reversing the magnetic field.According to the method described above, after a recording start command is given, erasing can be performed immediately without reversing the magnetic field. In other words, after a recording start command is issued, normally (1) applying a magnetic field in the erasing direction, (2) erasing, (3) applying a magnetic field in the recording direction, (4) recording, and (5) confirming reproduction. Whereas recording is performed in the order of
.

An embodiment of the present invention will be described below with reference to the drawings. A means 2 for detecting the end of the erasing process in the series of recording operations, which is built in a controller 1 for controlling the magneto-optical drive, in a series of recording operations performed in the order of erasing, power distribution, and confirmation playback. , means 3 for detecting the end of the recording process in the series of recording operations, bias magnetic field control means 4 for quickly reversing the bias magnetic field at each detection section, and bias magnetic field applying means 5. Of course, the controller 1 also has control means for laser light arc control, servo arc control, address arc control, playback signal control, etc.These are completely the same as conventional ones, and are not directly related to the present invention. Even though they are omitted because they are not available, with these configurations, in a series of recording operations performed in the order of erasure, power distribution, and confirmation playback, at the end of the erasing process in the above series of recording operations, and at the end of the above series of recording operations. Even if the magnetic field is reversed at the end of each recording process, in other words, the magnetic field is reversed only immediately after direct recording, and as a result, the magnetic field is always applied in the same direction during erasing and reproducing.4a The recording film of the disc used was T.
It is composed of bFeCo, is rich in transition metals, and has a coercive force of 20 Koe at room temperature.The reproduction characteristics obtained with this structure are explained below. In a series of recording operations performed in the order of erase, power distribution, and confirmation playback, magnetic field application in the erase direction is required in addition to address seek.
...20ms e c erase ・
... 2m5ec Magnetic field application in the recording direction ...20
m5ec record...2ms e
Confirmation playback requires a total of 46 ms eC of 2 m 5 ecs, whereas with this method, a magnetic field in the erasing direction is already applied at the start of the erasing process, so erasure... 2 ms e c recording time. Application of magnetic field in the direction...20ms e c recording
... 2m5ec confirmation playback
... It only takes a total time of 26 msec (2m5ec).

As described above, according to this embodiment, by restricting the magnetic field applied during reproduction in the erasing direction, it is possible to shorten the time required for consecutive recording operations. Since the magnetic field is directed in the erasing direction at the same time, there is normally no waiting time for directing the magnetic field in the erasing direction. This figure shows the configuration of a second embodiment of the invention, in which the above-mentioned series of recording operations are performed in the order of erasing, power distribution, and confirmation playback. means 6 for detecting the start of the erasing process in the series of recording operations, means 7 for detecting the start of the recording process in the series of recording operations, and means 8 for detecting the start of the reproduction process in the series of recording operations;
It is comprised of a means 9 for controlling the magnetic field applying means so as to apply a magnetic field in the same direction during erasing and reproducing based on these determination results, and a bias magnetic field applying means 10.

Of course, in the controller 1 (as in the first embodiment)
In addition, it also has control means for laser beam arc control, servo arc control, address arc control, reproduction signal control, etc. These are completely the same as conventional ones, and are omitted because they are not directly related to the present invention. .

In normal use, the mode is playback before erasing, and with these configurations, in a series of recording operations in which erasing, power distribution confirmation playback, etc. The magnetic field is reversed at each start of the reproduction process in the series of recording operations.

In other words, the magnetic field is reversed only immediately after direct recording, and as a result, the magnetic field is always applied in the same direction during erasing and reproducing.

At this time, since the magnetic field is directed in the erasing direction while starting reproduction, there is no waiting time for directing the magnetic field in the erasing direction (l With these configurations, the same effect as in the first embodiment can be obtained. Now let's talk about the third example.T as a recording film
By changing the amount of Tb in bFeCo, we fabricated disks with coercive forces varying from 5 Koe to 20 Koe at room temperature. Linear speed 7
．． Continuous reproduction was performed 106 times with an erase magnetic field of 4000 e applied at 5 m/s. At this time, when the reproduction power was large, the domain wall of the recorded domain moved and the jitter gradually increased. FIG. 3 shows the relationship between the maximum permissible power during reproducing and the coercive force of the recording film, assuming that the reproducing power reaching 7% of the data window is the maximum permissible power during reproducing. The maximum allowable power during playback is usually 1.
A coercive force of 5 rnW or more is desired.In the present invention, in which an erase magnetic field is always applied during reproduction, a coercive force of 14 Koe or more at room temperature is required for a transition metal-rich film. As T
By changing the amount of Tb in bFeCo, disks with coercive force varying from 10 Koe to 20 Koe at room temperature were fabricated.Although these disks were all rich in rare earth elements, the same method as in the third example was made using these disks. The results of the measurements are shown in Figure 4. The maximum permissible power during reproduction (usually 1.5 mW or more is desired), and in the present invention, where an erase magnetic field is always applied during reproduction, a coercive force of 10 Koe or more at room temperature is required for a transition metal-rich film. In the third and fourth embodiments, TbFeCo was used as the recording film.
Even if alloys such as dTb and DyTb are used, the effects of the present invention (as described above) can be obtained. The bi and ass magnetic fields are reversed only during playback, and a magnetic field in the erase direction is always applied during playback.This greatly reduces the time required for a series of recordings, consisting of erase and power distribution confirmation playback.

[Brief explanation of the drawing]

FIG. 1 shows a block doctor configured in a first embodiment of the present invention. FIG. 2 shows a block doctor configured in a second embodiment of the present invention. FIG. 3 shows a block doctor configured in a transition metal-rich recording film. Characteristics of the maximum permissible power during reproduction in a rare earth-rich recording film @ Fig. 4 is a characteristic diagram of the maximum permissible power during reproduction in a rare earth-rich recording film. 1... Controller, 2... Detection of end of erasure process, half-set 3... Detection of end of recording process, half-set 4... Bias magnetic field control, half-set 5... Bias magnetic field application, half-set 6... Start of erasure Detection half-immersion 7...Recording start detection half-immersion 8...Reproduction start detection means, 9...Bias magnetic field control half-immersion 10...Bias magnetic field application hand skin Name of agent Patent attorney Akira Kokaji 2 people-1 1g 2 Figure 113
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(in Oe)

Claims (5)

[Claims] (1) In a magneto-optical recording/reproducing device equipped with a means for applying a bias magnetic field in the opposite direction to the light beam irradiation position on the surface of the magneto-optical recording medium during recording and erasing, the bias magnetic field is applied in the same direction as during erasing during reproducing. A method for recording, reproducing and erasing information on a magneto-optical recording medium, the method comprising applying a bias magnetic field. (2) The recording film is composed of a rare earth-transition metal ferrimagnetic film, is rich in transition metals, and has a coercive force of 14 Koe at room temperature.
The method for recording, reproducing and erasing information on a magneto-optical recording medium according to claim 1. (3) The recording/reproducing/erasing method for a magneto-optical recording medium according to claim 1, wherein the recording film is composed of a rare earth-transition metal ferrimagnetic film, is rare earth rich at room temperature, and has a coercive force of 10 Koe or more. (4) Install means for applying a bias magnetic field to the light beam irradiation position on the surface of the magneto-optical recording medium, and perform a series of recording operations on the magneto-optical recording medium in the order of erasing and recording.
means for detecting the end of the series of recording operations; means for quickly reversing the bias magnetic field after detecting the end of the series of recording operations; and means for detecting the end of the erasing process in the series of recording operations. and a magneto-optical recording and reproducing apparatus characterized by comprising means for quickly re-inverting the bias magnetic field after detecting the end of the erasing process in the series of recording operations. (5) A means for applying a bias magnetic field to the light beam irradiation position on the surface of the magneto-optical recording medium, a means for determining the start of each mode of recording, reproduction, and erasing, and based on the determination result, during erasing and reproduction. 1. A magneto-optical recording and reproducing apparatus comprising: and means for controlling a magnetic field applying means so as to apply a magnetic field in the same direction.