JPH0369004A - Magneto-optical recording device - Google Patents

Abstract

PURPOSE:To allow the rewriting of data in a short period of time by erasing the recording of another group simultaneously at the time of recording of information in one groove with the recording film of two data regions. CONSTITUTION:A light beam 1 emitted from a laser diode is converged by an objective lens 2 onto the recording tracks of the group A of a magneto- optical disk 6 rotated by a motor 5, by which the data is written. A driving current is applied to a coil 3 from a current control circuit 4 right under the point where the spot is formed, by which the direction of the recording magnetic field of the spot part is controlled. The intensity of the light beam is increased and is magnetized all to the recording level to erase the recording when the spot comes to the position above the B grooves. The recording is executed in the previously erased groove at every execution of the writing in this way and the previously recorded groove is formatted to erase the recording.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magneto-optical recording and reproducing device that records information at high density by creating upward and downward residual magnetization perpendicular to the surface of a recording medium. It is.

[Conventional technology]

In recent years, recording devices that use magneto-optical disks have become known as devices for storing large amounts of information. Like laser disks and compact disks, these devices can record and reproduce information at high density without contact, and can be accessed at high speed. It has the characteristic of being wet. Furthermore, since the recording film of the disk is made of a magnetic material, it has the characteristic that recording and erasing can be repeated.

As this magneto-optical recording method, an optical modulation method and a magnetic field modulation method are known. The optical modulation method records by turning the recording laser beam on and off according to the recording signal, and it is necessary to change the direction of the magnetic field between recording and erasing by reversing the magnet. Overrides that perform simultaneous recording are not allowed. On the other hand, the magnetic field modulation method performs recording by irradiating a recording laser beam at a constant level and reversing the alternating magnetic field using an electromagnet in accordance with the bit signal of the recording data.
Although overriding is theoretically possible, in reality it is difficult to generate a magnetic field with the strength necessary to reverse the magnetization of the recording film at a high frequency using an electromagnet, so it is not suitable for high-density recording.

[Problem to be solved by the invention]

In this way, the optical modulation method is optimal for high-density recording, but in order to rewrite information, it is necessary to first erase and then record, and the recording medium must be rotated at least twice. When recorded data is frequently rewritten and used, the problem of long access time remains.

Therefore, the present invention provides a magneto-optical recording device that performs pseudo override without requiring a high-frequency alternating magnetic field and enables high-speed access.

[Means to solve the problem]

A magneto-optical recording device according to the present invention defines a plurality of data areas on a recording film of a magneto-optical recording medium and records information in these data areas by changing the direction of magnetization. a magnetism generating means capable of reversing a magnetic field in one direction; a means for dividing the data area into at least a first group and a second group and identifying them; means for recording information in a group and aligning the magnetization direction of the other group to erase the recording; means for recording the one magnetic field direction for the desired data area on the magneto-optical recording medium; Means for applying a magnetic field in the opposite direction to the one magnetic field direction to the desired data area in which information has been recorded, aligning the magnetization direction of the one group to erase the recording, and at the same time recording in the other group. It is characterized by having the following.

[Effect]

Therefore, since one of the two groups in each data area is always in the erased state, it is sufficient to perform a recording operation on this group and an erase operation on the other group.
These recording and erasing operations can be completed in one access.

〔Example〕

FIG. 2 shows a schematic diagram of an embodiment of a magneto-optical recording device using this recording method. Light beam emitted from a laser diode
is focused by the objective lens 2 onto a recording track of a magneto-optical disk 6 which is rotationally driven by a motor 5, thereby forming a light spot. Further, a driving current is applied to the coil 3 by a current control circuit 4 immediately below where the spot is formed, thereby controlling the direction of the recording magnetic field at the spot.

When recording with the above recording device, each sector 7 on the recording disk 6 has an ID area 7a,
Data record S! An area 7b and a blank area 7C are provided, and the data recording area 7b is divided into two groups, A and B. In this case, as shown in FIG. 1(a), each bit in the recording area of one sector is allocated alternately to A and B. Immediately after formatting of such a magneto-optical disk 6, the data area is magnetized, for example, in the upward direction for each bit of the A group and B group, as shown in FIG.

8-bit data a = ”100 in this data area
When writing "11101", data is written to the bits of group A while applying a downward magnetic field by the coil 3. In other words, when the spot of the laser beam comes on the bits of group A, the data is written based on "13" of the data to be recorded. By increasing the laser beam intensity and reversing the magnetization direction downward,
For "O", the laser beam intensity is lowered so as not to invert. Also, when the spot comes into focus in group B,
Increase the laser beam intensity to the recording level and align all magnetization directions downward. As a result, a signal based on the recorded data is written into the bits of the A group, and all the bits of the B group are magnetized downward and the recording is erased.

For example, the data of this sector is data b ='01100
When rewriting to 111m, an upward magnetic field opposite to the downward magnetic field applied during the previous recording is applied by the coil 3, and for group B, only the level "1" bit in the recording data b is inverted, and the above data b is rewritten. is written, and all the focus points in group A are magnetized upward and formant.

Each time writing is performed in this way, the previously erased group is recorded using a magnetic field opposite to that used in the previous recording, and the previously recorded group is formatted and its recording is erased. In this way, each time a new write is performed, the direction of the magnetic field and the group for writing data are exchanged.

In addition, each time recording is performed, the direction of the magnetic field and the name of the group that wrote the data should be recorded in the ID area 7a at the beginning of each sector, and should be added to each sector for the next recording. The direction of the magnetic field and the group name to be recorded are read, and the recording as described above is performed without error. in this case,
Since the magnetic field reversal interval is at least equal to each sector interval,
The frequency of the alternating magnetic field may be relatively low.

In the above embodiment, the two groups are arranged alternately with one bit each, but the present invention is not limited to each group, but may also be arranged with multiple bits alternately. ! The first half of the area may be set as group A, and the second half may be set as group B.

〔Effect of the invention〕

According to the present invention, since recording and erasing can be performed simultaneously in one access, data can be rewritten in a short time.

[Brief explanation of drawings]

FIG. 1 is a data arrangement diagram showing an embodiment of the present invention, and FIG. 2 is a schematic diagram showing an example of a magneto-optical recording device according to the present invention. l...Light beam 2...Objective lens 3...Coil 4...Current control circuit 5...Motor 6...Magneto-optical disk

Claims (1)

[Claims] Defining multiple data areas on the recording film of the magneto-optical recording medium,
In a magneto-optical recording device that records information in these data areas by changing the magnetization direction, a magnetism generating means capable of reversing a magnetic field in two directions with respect to a recording film is provided, and the data area is arranged in at least a first group and a second group. means for recording information in one of the groups within a desired data area in one magnetic field direction and erasing the recording by aligning the magnetization direction of the other group; means for recording the one magnetic field direction for the desired data area on the magneto-optical recording medium;
Applying a magnetic field in the opposite direction to the one magnetic field direction to the desired data area where the information has been recorded to align the magnetization direction of the one group to erase the record and record in the other group. 1. A magneto-optical recording device comprising: means.