JPH0514976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an information recording and reproducing apparatus that records information on or reproduces information on a disk-shaped recording medium.

This type of device, such as a magneto-optical disk device,
Fe.Gd. on the surface of a substrate such as glass as a recording medium.
A magneto-optical disk carrying a ferromagnetic thin film made of an alloy such as Tb is used. When recording information on a magneto-optical disk, the magnetization direction of the ferromagnetic thin film on the magneto-optical disk is aligned in advance in one direction perpendicular to the disk surface. Next, a light beam spot (approximately 1μ
m). Then, the temperature of the area irradiated by the light beam spot rises due to the energy of the light beam, reaching the Curie point (160°C) or higher, and the predetermined magnetization direction becomes disordered. As the magneto-optical disk rotates, the area irradiated by the light beam spot also moves, and the temperature of the irradiated area decreases. At this time, it is magnetized in the opposite direction to the surroundings by an external magnetic field. In this way, information is recorded on the ferromagnetic thin film as a reversal of the magnetization direction.

Next, the case of playback will be explained. An unmodulated light beam spot is irradiated onto a rotating magneto-optical disk. Then, a portion of the light beam is reflected on the magneto-optical disk surface. This reflected light passes through a known beam splitter, analyzer, etc., enters the photoelectric conversion element, and is extracted as a reproduced signal. In other words, when this reflected light is reflected on the magneto-optical disk surface, the plane of polarization is rotated (due to the well-known Kerr effect) according to the direction of magnetization, and from this direction of polarization, the direction of magnetization of the ferromagnetic thin film can be determined ( This polarization direction is selected by an analyzer provided immediately before the photoelectric conversion element), and is extracted from the photoelectric conversion element as a reproduced signal.

A feature of this type of device is that it uses a light beam spot narrowed to approximately 1 μm to perform recording and playback, making it possible to perform high-density recording, which is one to two orders of magnitude higher than that of magnetic disks. It has density. For example, an A4 magneto-optical disk with a diameter of 300 mm
It is possible to record 10,000 pages of original size at a resolution of 16 lines/mm. Furthermore, since information is recorded as a change in the magnetization direction, once recorded information can be erased, and therefore, it is possible to erase information that is no longer needed and re-record new information.

Generally, when erasing information, an information track is erased by an unmodulated light beam (one information track) while applying an external magnetic field in the opposite direction to that used during recording.
Scan each time. Then, the magnetization direction of the information track can be reversed to the state before recording, that is, erased, by a process similar to that during recording.

However, when erasing the entire recording medium on a magneto-optical disk in order to completely rewrite it, the above-mentioned method takes too much time and is not practical. Therefore, conventional methods have been to move the permanent magnet 1 in the radial direction (arrow direction) of the magneto-optical disk 2 as shown in FIG. 3 were installed in parallel, and the entire surface was erased by energizing the electromagnet 3.

However, in the above case, a complicated mechanism such as a wire mechanism or a screw feeding mechanism is required as a means for moving the permanent magnet 1 in the radial direction of the magneto-optical disk 2, and the recorded information on the innermost track is also securely moved. When moving the permanent magnet 1 to the innermost circumferential side to erase data, be careful not to hit the permanent magnet 1 etc. with the spindle motor (not shown) that rotates the magneto-optical disk 2 (in the direction of the arrow in Fig. 1). A means of stopping it reliably was needed. In the latter case, as mentioned above, a moving means is not required, but the electromagnets must be arranged from the outermost position to the innermost position to ensure that no erase is missed, and therefore the number of parts is reduced. There was a problem with many expensive items.

SUMMARY OF THE INVENTION An object of the present invention is to provide an information recording/reproducing apparatus that solves the above-mentioned problems and can provide a simple, low-cost erasing mechanism.

In order to achieve this object, the present invention provides a magnet for erasing recorded information, and a part of the rotation trajectory of the magnet while maintaining an equal distance from the recording area surface of the disk-shaped recording medium. A full-surface erasing mechanism is formed by a magnet rotating means that rotates the magnet so as to radially cross the recording area, and a magnet stopping means that stops the magnet at a position outside the recording area of the disk-shaped recording medium. The feature is that the entire surface is erased by rotational movement of.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 3 is a partially cutaway perspective view schematically showing a magneto-optical disk device according to an embodiment of the present invention. 4 is a magneto-optical disk carrying a ferromagnetic thin film made of an alloy such as Fe.Gd.Tb on its surface; 5 is a spindle motor that rotates the magneto-optical disk 4 in the direction of the arrow;
A turntable 6 is fixed to the rotating shaft of the spindle motor 5. Reference numeral 7 denotes a clamp member having a conical end surface, and has the role of pressing and fixing the magneto-optical disk 4 against the turntable 6. Reference numeral 8 indicates a recording/reproducing head which is driven along guide rails 9 and 10 fixed to the main body of the apparatus by a drive mechanism (not shown) such as a motor, and reference numeral 11 indicates a turntable 13 which is rotated in the direction of the arrow by a drive motor 12. Permanent magnet 14 fixed to the outermost circumferential side of the upper surface of turntable 13, position a where permanent magnet 14 is indicated by the dotted line
This is a full-scale erasing mechanism consisting of a permanent magnet 16 fixedly held by a support plate 15 so that the polarity surface different from that of the permanent magnet 14 faces the permanent magnet 14 when the magneto-optical disk reaches a position outside the 4th surface of the magneto-optical disk. be.

The turntable 13 is arranged parallel to and partially overlaps the magneto-optical disk 4 in the vertical direction. Therefore, the permanent magnet 14 is rotated by the rotation of the turntable 13 while maintaining an equal distance from the recording area surface of the magneto-optical disk 4. The rotation locus of the permanent magnet 14 is determined so that a portion thereof crosses the recording area of the magneto-optical disk 4 in the radial direction (outermost track←→innermost track). still,
The above-mentioned equal spacing with respect to the magneto-optical disk 4 is an interval determined at a distance at which the magnetic field of the permanent magnet 14 can cause magnetization reversal of the ferromagnetic thin film on the magneto-optical disk 4.

Next, the operation will be explained. magneto-optical disk 4
When erasing all the information recorded on the disk by the recording/reproducing head 8, the drive motor 12 is energized while the magneto-optical disk 4 is kept rotating (by the spindle motor 5), and the permanent magnet 14 is turned on. (Turntable 13) is rotated once. Then, due to the magnetic field of the permanent magnet 14, the magnetization direction of all recorded information (information tracks) formed on the magneto-optical disk 4 is uniformly aligned in a predetermined direction (opposite direction to that during recording), and the recorded information is Erasure is performed. At this time, during the rotation of the magneto-optical disk 4, all the recorded information is transferred to the permanent magnet 14 while the permanent magnet 14 rotates once.
It has a speed that can be erased by still,
If the recorded information cannot be completely erased during one rotation of the permanent magnet 14, the permanent magnet 14 is rotated multiple times. After erasing the recorded information is completed, the power supply to the drive motor 12 is stopped. At this time, even if the power supply to the drive motor 12 is stopped, the rotation of the turntable 13 does not stop immediately.
The turntable 13 continues to rotate due to inertia. Then, the rotation stops when the permanent magnet 14 reaches position a. That is, since the permanent magnet 16 fixedly held on the support plate 15 and the permanent magnet 14 have different polarities, when the permanent magnet 14 reaches the position a, an attractive force acts between the permanent magnet 16 and the permanent magnet 16. The rotation of the turntable 13 is stopped.

After recording new information, if the recorded information is to be erased, the drive motor 12 is energized, the turntable 13 (permanent magnet 14) begins to rotate, and the recorded information can be erased. At this time, the starting torque of the drive motor 12 is
Since the attraction force between the permanent magnet 16 and the permanent magnet 16 is greater, the turntable 13 can be rotated against the attraction force.

According to this embodiment, the permanent magnet 14 for erasing recorded information is rotated at equal intervals to the recording area surface of the magneto-optical disk 4 so as to traverse the recording area of the magneto-optical disk 4 in the radial direction. Since information is erased and the permanent magnet 14 is stopped at a position away from the magneto-optical disk 4 after the erasure is completed, stable information erasure can be performed. Further, the drive motor 12 for rotating the permanent magnet 14 does not need to have high performance, and an inexpensive commercially available motor is sufficient, and other parts do not need high performance, and furthermore, a small number of parts can be used. Therefore, the entire erase mechanism 11 becomes a simple mechanism and a low-cost one.

In this embodiment, the turntable 13 and the drive motor 12 correspond to the magnet rotating means of the present invention, and the permanent magnet 16 and the support plate 15 correspond to the magnet stopping means.

In the illustrated embodiment, a permanent magnet 14 is used as a magnet for erasing recorded information, but an electromagnet may be used instead. Similarly, an electromagnet can be used instead of the permanent magnet 16. In this case, a circuit for turning on and off the electromagnet must be added, resulting in a somewhat complicated configuration, but since the electromagnet can be turned off when erasing starts, there is no binding force on the permanent magnet 14. , drive motor 12
The advantage is that the starting torque is small.
Further, a stepping motor may be used as the drive motor 12. However, in this case, no special stopping means is required, and the stopping means is a means for stopping energization to the motor.

Further, in this embodiment, a magneto-optical disk device is used as the information recording/reproducing device, but the present invention is not limited to this, and the present invention can also be applied to a magnetic disk device.

As explained above, according to the present invention, the magnet for erasing recorded information and the magnet are kept at equal intervals with the recording area surface of the disk-shaped recording medium, while a part of the rotation locus is on the disk-shaped recording medium. A full-surface erasing mechanism is formed by a magnet rotating means that rotates the magnet so as to radially cross the recording area, and a magnet stopping means that stops the magnet at a position outside the recording area of the disk-shaped recording medium. Since the entire surface is erased by the rotational movement of , the entire surface erasing mechanism can be made simple and inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a side view schematically showing an example of a conventional entire surface erasing mechanism, FIG. 2 is a side view schematically showing another example of the conventional surface erasing mechanism, and FIG. FIG. 2 is a partially cutaway perspective view. 4... Magneto-optical disk, 8... Recording/reproducing head, 11... Whole-plane erasing mechanism, 12... Drive motor, 13... Turntable, 14... Permanent magnet, 15... Support plate, 16... Permanent magnet , a...
position.

Claims (1)

[Claims] 1 Information recorded on a disk-shaped recording medium,
In an information recording and reproducing device equipped with a full-scale erasing mechanism that completely erases recorded information, a magnet that erases recorded information;
The magnet is rotated so that a part of its rotation locus crosses the recording area of the disk-shaped recording medium in the radial direction while maintaining an equal distance from the recording area surface of the disk-shaped recording medium.
An information recording/reproducing device characterized in that the entire erase mechanism is formed by a magnet rotating means for rotating the magnet and a magnet stopping means for stopping the magnet at a position outside a recording area of a disk-shaped recording medium.