JPH04177644A - Megnetooptical compact disk drive - Google Patents

Abstract

PURPOSE:To realize real-time rewrite in a simulated manner by reading out recorded data at a high speed by dividing them for each one track at a speed two to three times as high as the one at the time of reproduction and by executing erasure of pre-data, recording of fresh data, etc., on the occasion of the rewrite of data. CONSTITUTION:Recorded data 4 to be rewritten afresh are divided for each one track on a magnetooptical compact disk 1 by a dividing means 5 being synchronous with a signal from a spindle motor 2 and the recorded data divided are stored in a buffer memory 6. On the occasion of the rewrite of the data, a disk 1 is rotated at a linear speed twice as high as the one at the time of reproduction. At the first rotation thereof, a magnetic field impressing device 10 is controlled in the direction of an erasing magnetic field and a drive circuit 9 is so controlled as to generate an erasing power, by a control signal from a timing control circuit 8 being synchronous with the signal from the motor 2, whereby erasure is executed. At the second rotation, the device 10 is controlled in the direction of a recording magnetic field by the control signal from the circuit 8 and the data read out from the memory 6 at a high speed are recorded by a means 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical compact disk device in which information can be rewritten using a magneto-optical recording method.

[Conventional technology]

By using focused light to reproduce the data on the disc, compact discs can store extremely high-density, large-capacity information in the form of digital signals. Magneto-optical compact discs using a magneto-optical recording method have been developed so that users can easily rewrite data on such high-performance compact discs by themselves, similar to a table recorder.

A magneto-optical compact disc is a recording film made of a perpendicularly magnetized film such as a Tb-Fe thin film formed on a transparent disc-shaped substrate. By simultaneously applying a bias magnetic field perpendicularly to the magneto-optical recording film using a bias magnetic field generating coil,
The direction of magnetization of the recording film can be recorded as recording data in the portion irradiated with the light spot.

In the case of the commonly used optical intensity modulation recording method, when rewriting information, a focused laser beam is irradiated while applying a -degree erasure magnetic field (-He) to raise the irradiated area to a temperature above the Curie temperature. After that, in the process of cooling the recording film, an erasing operation is performed to uniformly align the direction of magnetization in the direction of the erasing magnetic field, and then a recording magnetic field (Hw) in the opposite direction to the erasing magnetic field is applied to generate a laser beam. By turning it on and off, information is recorded as the direction of magnetization. Therefore, since override is not possible, the transfer speed is effectively reduced during recording.

[Problem to be solved by the invention]

With this conventional technology, automatic writing cannot be performed in the case of optical intensity modulation recording in which recording is performed by modulating the recording data while applying a constant magnetic field strength, so when rewriting data, - It was necessary to erase the pre-data before recording new data.

In addition, in order to further improve reliability, it is necessary to verify whether the recorded data is correctly recorded, which requires three times as much time as erasing, recording, and verifying.

In particular, since compact discs are used to store continuous data such as music and video, conventional methods have had the problem of requiring a very long time to rewrite the data.

The object of the present invention is to double or triple the linear velocity of the magneto-optical compact disk compared to the reproduction speed and erase and record, or erase and erase data while rotating two or three times, respectively, when rewriting data. An object of the present invention is to provide a magneto-optical compact disk device that can realize pseudo real-time rewriting by performing recording and verifying.

[Means to solve the problem]

The magneto-optical compact disk device of the present invention includes an optical head that records, erases, or reproduces information by irradiating focused laser light onto the recording film surface of the magneto-optical compact disk, and a magneto-optical compact disk that rotates at a constant linear velocity. In a magneto-optical compact disk device, the magneto-optical compact disk device includes a rotating means for rotating the magneto-optical compact disk, and a bias magnetic field applying device for applying a necessary magnetic field strength onto the magneto-optical compact disk recording film surface. A dividing means for dividing into tracks, a buffer memory for storing digital data for l tracks divided by the dividing means, and a dividing means for dividing the digital data into half on the time axis. The magneto-optical compact disk is equipped with a signal processing means for high-speed reading and recording data, and when rewriting data, the magneto-optical compact disk is rotated at a linear velocity twice the linear velocity during reproduction, and the pre-recording is performed in the first rotation. It is characterized in that data is erased, and in the next rotation, the recorded data read out at high speed by the signal processing means is recorded. Alternatively, the signal processing means reads the digital data stored in the buffer memory at a high speed of one-third on the time axis, and when rewriting the data, the signal processing means reads the digital data stored in the buffer memory at a linear speed three times the linear speed at the time of reproduction. The magneto-optical compact disk is rotated, the pre-data is erased in the first rotation, the recorded data read out at high speed by the signal processing means is recorded in the next rotation, and the recorded data is erased in the next rotation. It is characterized by verifying the data obtained.

[Effect]

With the above-described configuration, the magneto-optical compact disk device of the present invention doubles or triples the linear velocity of the magneto-optical compact disk when rewriting data, and transfers the recorded data to one level on the magneto-optical compact disk. The recorded data is divided into tracks, and each divided recording data is read out in half or third at high speed. While the magneto-optical compact disc makes two or three revolutions, pre-data is erased and new data is added. Deleting records or pre-data 2
Record new data and verify the recorded data.

During reproduction, it is possible to reproduce at the same speed as the recorded data by returning the normal linear velocity. Thereby, when rewriting data, it is possible to perform erasing and recording, or erasing, recording, and verifying at the same time as recorded data, making it possible to realize pseudo real-time rewriting.

[Actual travel example]

Next, a practical example of the present invention will be described with reference to the drawings.

FIG. 1 is a basic configuration diagram showing a preferred embodiment of the magneto-optical compact disk device δ of the present invention, and FIGS. 2 and 3 respectively show an example of a time chart and another example when rewriting data in this embodiment. It is a diagram.

In FIG. 1, 1 is a magneto-optical compact disk, 2 is a spindle motor that rotates the magneto-optical compact disk at a constant linear velocity, 3 is an optical head that records, erases or reproduces data on the magneto-optical compact disk, and 4 is a spindle motor that rotates the magneto-optical compact disk at a constant linear velocity. Recorded data to be rewritten; 5 is dividing means for dividing the recorded data 4 into one track on the magneto-optical compact disk 1; 6 is a buffer memory for storing the divided digital data; 7 is digital data stored in the buffer memory 6. 8 is a signal processing means for high-speed reading of 1/2 or 1/3 on the time axis.

A timing control circuit controls the timing of recording, verifying, etc.; 9 is a semiconductor laser drive circuit that drives a semiconductor laser that is the light source of the optical head 3; and 10 is a bias magnetic field applying device.

These operations will be explained below with reference to the time chart of FIG. 2.

In FIG. 2, A indicates recorded data 4 to be newly rewritten, which is divided into sections on the magneto-optical compact disk 1 by a dividing means 5 synchronized with the signal from the spindle motor 2, and the divided recorded data is stored in a buffer. It is stored in memory 6. B is digital data obtained by reading out the recorded data stored in the buffer memory 6 at high speed by half on the time axis by the signal processing means 7.

Here, when rewriting data, the magneto-optical compact disk l rotates at twice the linear velocity during playback, so 1
The disk rotates twice for each track of data.

Then, as shown in time chart C, in the first rotation, the bias magnetic field applying device 10 is controlled to be in the erase magnetic field direction by the control signal from the timing control circuit 8 synchronized with the signal from the spindle motor 2, Furthermore, the pre-data is erased by controlling the semiconductor laser drive circuit 9 to generate erasing power.

Next, in the second rotation, the bias magnetic field applying device 10 is controlled to be in the recording magnetic field direction by the control signal from the timing control circuit 8 synchronized with the signal from the spindle motor 2, and the semiconductor laser drive circuit 9 is New data is recorded by driving in accordance with high-speed read data B read out at high speed by the signal processing means 7.

Another example will be explained with reference to the time chart of FIG.

In FIG. 3, A indicates the recorded data 4 to be newly rewritten, which is divided into tracks on the magneto-optical compact disc 1 by the dividing means 5 synchronized with the signal from the spindle motor 2, and the divided recorded data is B' is stored in the rough memory 6, and B' is the signal processing means 7.
This is digital data obtained by reading out the recorded data stored in the buffer memory 6 at a high speed of one-third on the time axis.

When rewriting data, the magneto-optical disk rotates at a linear velocity three times that of reproducing data, so 1
The disk rotates three times for each track of data.

Then, as shown in time chart C', in the first rotation, the bias magnetic field applying device 10 is controlled in the direction of the erase magnetic field by the control signal from the timing control circuit 8 synchronized with the signal from the spindle motor 2. ,Also,
Pre-data is erased by controlling the semiconductor laser drive circuit 9 to generate erasing power.

Next, in the second rotation, the spindle motor 2 controls the direction so that the direction of
′, new data is recorded.

Furthermore, in the third rotation, the newly recorded data is read by controlling the semiconductor laser drive circuit 9 to generate reproduction power using a control signal from the timing control circuit 8 synchronized with the signal from the spindle motor 2. The reproduced data and high-speed read data B'
Verification can be performed by comparing.

Here, in order to maintain compatibility, the specifications of the magneto-optical compact disc are the same as those of the playback-only compact disc: the linear velocity during playback is approximately 1.2 m/s, and the maximum recording frequency is approximately 720 kHz. be. Therefore, even if the linear velocity triples, the linear velocity will only be 3.6 m/s at most.
Since the maximum recording frequency is approximately 2.2 MHz, it is possible to record and erase data.

〔Effect of the invention〕

As explained above, when rewriting data, the magneto-optical compact disk device of the present invention doubles or triples the linear velocity of the magneto-optical compact disk as that during playback, and transfers recorded data onto the magneto-optical compact disk. The recorded data is divided into one track at a time, and the divided recorded data is read out at high speed into one-half or one-third, and while the magneto-optical compact disc makes two or three revolutions, pre-data is erased and new data is added. Deletion of records or pre-data,
Record new data and verify recorded data. At the time of reproduction, it is possible to reproduce at the same speed as the recorded data by reproducing at a normal linear velocity. Thereby, when rewriting data, it is possible to perform erasing, recording, or erasing, recording, and verifying at the same time as recorded data, and it is possible to realize pseudo real-time data rewriting.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram showing one embodiment of the magneto-optical compact disk device of the present invention, and FIGS. 2 and 3 show one example and another example of a time chart when rewriting data in this embodiment, respectively. It is a diagram. 1...Magneto-optical compact disc, 2...
...Spindle motor, 3...Optical head, 4.
...Recorded data, 5...Dividing means, 6...
... Buffer memory, 7 ... Signal processing means, 8 ... Timing control circuit, 9 ...
Semiconductor laser drive circuit, 10... Bias magnetic field application device, A... Recorded data, B, B'...
...High-speed read data, c, c' ...Time chart. Agent Patent Attorney Oto Uchihara

Claims (1)

[Claims] 1. An optical head that records, erases, or reproduces information by irradiating a focused laser beam onto the recording film surface of a magneto-optical compact disk, and a rotation that rotates the magneto-optical compact disk at a constant linear velocity. and a bias magnetic field applying device for applying a necessary magnetic field strength onto the magneto-optical compact disk recording film surface, the magneto-optical compact disk device includes a bias magnetic field applying device that applies a necessary magnetic field strength onto the magneto-optical compact disk recording film surface, the data to be recorded is distributed over one track on the magneto-optical compact disk. a buffer memory for storing one track's worth of digital data divided by the dividing means; and a buffer memory for storing the digital data for one track divided by the dividing means; When rewriting data, the magneto-optical compact disk is rotated at a linear velocity twice the linear velocity during reproduction, and the pre-data is read out during the first rotation. A magneto-optical compact disk device, characterized in that after erasing, the recorded data read out at high speed by the signal processing means is stored in the next rotation. 2. The signal processing means reads the digital data stored in the buffer memory at a high speed of one-third on the time axis, and when rewriting the data, the signal processing means reads the digital data stored in the buffer memory at a linear velocity three times the linear velocity during reproduction. rotate the magneto-optical compact disk with
Pre-data is erased in the first revolution, recorded data read out at high speed by the signal processing means is recorded in the next revolution, and further, the recorded data is verified in the next revolution. 2. A magneto-optical compact disc device according to claim 1.