JP3503764B2 - Magneto-optical recording method and magneto-optical recording device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording method and a magneto-optical recording apparatus, and can be applied to, for example, high density recording of desired data on a magneto-optical disk.

[0002]

2. Description of the Related Art Conventionally, as a recording / reproducing method for a magneto-optical disk device, an edge position for shifting the edge positions of the front end and / or the rear end of an information bit from a predetermined reference position in a step-like manner according to data to be recorded. It has been proposed to record and reproduce data by modulation (Japanese Patent Application No. 5-12).
No. 6437). According to this recording / reproducing method, changes in the pit length and the position of the pit edge can be detected with high accuracy, and it becomes possible to record and reproduce information with minute changes that have been considered impossible until now. Higher density recording than ever can be realized.

As described above, the principle of recording data on the magneto-optical disk by the edge position modulation is as follows. First, as shown in FIG. 3, PWM (Pulse Width) is applied to the recorded data.
Modulation) A modulated recording signal (FIG. 3B) is generated. Then, an information pit (FIG. 3A) corresponding to the length at the time of the zero cross is formed. In this way, the position of the edge of the information pit will change to the reference clock (Fig.
The position shown in (C) changes from step to step. In accordance with this amount of change, it is possible to record, for example, data of 8 levels (that is, 3 bits) from 0 to 7 for one edge of the information bit.

As shown in FIG. 4, the principle of reproducing the data thus recorded is to amplify the RF signal (FIG. 4 (A)) reproduced from the magneto-optical disk and binarize it.
The F signal (FIG. 4 (B)) is obtained. Since a clock pit is formed on the magneto-optical disk on which data is recorded,
A reference clock (FIG. 4C) with this as a reference is generated, and in synchronization with this reference clock, a sawtooth wave signal (FIG. 4D) is further generated. Then, the position of the edge of the information bit is detected by detecting the value of the sawtooth wave signal at the timing when the sawtooth wave signal and the binarized RF signal cross each other, and the data thus recorded is reproduced. To do.

[0005]

By the way, in a magneto-optical disk device using the above-mentioned recording / reproducing method by edge position modulation of information bits, optical modulation recording is performed while applying an alternating magnetic field onto the magneto-optical disk. There is. That is, in this magneto-optical disk device, first, a recording basic clock synchronized with a reference clock obtained by reproducing the clock pit of the magneto-optical disk is generated, and an alternating magnetic field having the same frequency as that of the recording basic clock is generated to generate the magneto-optical disk. Is applied to the recording position of. At the same time, the phase of the basic recording clock is changed according to the information to be recorded, and the recording position of the magneto-optical disk is irradiated with laser light based on the basic recording clock to perform magneto-optical recording.

However, in the case of this magneto-optical disk device,
The information pit formed on the magneto-optical disk is written by the heat storage effect because the position of the information pit to be written next is shifted from the position to be originally written due to the position of the optical pulse of the preceding information. There was a problem that the pits could not be recorded reliably.

The present invention has been made in consideration of the above points, and a magneto-optical recording method and a magneto-optical recording method capable of surely recording with a simple structure when data is recorded by edge position modulation of an information bit. It is intended to propose a recording device.

[0008]

In order to solve such a problem, according to the present invention, the basic clock of the data (DR0) to be recorded is synchronized with the reference clock pre-recorded on the magneto-optical recording medium (2). Generates a basic recording clock (CLK) with the same frequency as, and slightly shifts the rising and falling edges of the basic recording clock (CLK) from the specified reference position in a step-like manner according to the data (DR0) to be recorded. Generated recording signal (DR1) and irradiating the laser light so that the recording area on the magneto-optical recording medium (2) has a constant temperature, the external magnetic field is modulated according to the recording signal (DR1), and data is recorded. (DR0) was recorded on the magneto-optical recording medium (2).

Further, in the present invention, a recording basic clock (CLK) synchronized with a reference clock prerecorded on the magneto-optical recording medium (2) and having the same frequency as the basic clock of the data (DR0) to be recorded is provided. Clock generating means (8) for generating and data to be recorded (DR0)
Recording signal generating means (9) for generating a recording signal (DR1) in which the positions of the rising and falling edges of the recording basic clock (CLK) are minutely displaced stepwise from a predetermined reference position in accordance with Magneto-optical recording data on the magneto-optical recording medium (2) by modulating the external magnetic field according to the recording signal (DR1) while irradiating the laser light so that the recording area on the medium (2) has a constant temperature. Recording means (5, 6,
10 and 11) are provided.

[0010]

The data (DR) to be recorded in synchronization with the reference clock previously recorded on the magneto-optical recording medium (2)
Data (DR0) to be recorded by generating a recording basic clock (CLK) having the same frequency as the basic clock of (0).
A recording signal (DR1) in which the positions of the rising and falling edges of the recording basic clock (CLK) are minutely displaced in a step-like manner from a predetermined reference position is generated according to the recording area on the magneto-optical recording medium (2). By irradiating the laser light so that the temperature becomes a constant temperature, the external magnetic field is modulated according to the recording signal (DR1) to record the data (DR0) on the magneto-optical recording medium (2). When the data (DR0) is recorded by the edge position modulation of the bits, it can be surely recorded with a simple configuration.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 generally indicates a magneto-optical disk device to which the magneto-optical recording method according to the present invention is applied. The magneto-optical disk 2 is rotationally driven by a spindle motor 4 controlled by a spindle servo circuit 3 so as to satisfy a specified rotational speed or linear velocity. Under the control of the laser power control circuit 6, the pick-up 5 irradiates the magneto-optical disk 2 with laser light, and irradiates an optical spot having a predetermined intensity necessary for magneto-optical recording or reproduction. The pickup 5 detects the reflected light from the magneto-optical disk 2 and demodulates the detection signals S _MO and S _RF from the demodulation / decoding circuit 7 and PL.
Output to the L (Phase Locked Loop) circuit 8.

The demodulation / decoding circuit 7 picks up the pickup 5 during reproduction.
The supplied signal (MO signal) S _MO is demodulated and decoded, and output to an output signal processing circuit (not shown).
The PLL circuit 8 receives an RF signal (light intensity signal) S _RF corresponding to a clock pit, which is previously formed as a prepit at a constant interval on the magneto-optical disc 2 by, for example, embossing, synchronizes with the clock pit, and outputs a magneto-optical signal. A clock (hereinafter referred to as a recording basic clock) C that matches the frequency of the basic clock of the signal to be recorded on the disk 2.
LK is generated and supplied to the multilevel digital phase modulation circuit 9.

An external magnetic field generating coil 11 for applying an external magnetic field to the magneto-optical disk 2 according to the control of the magnet drive circuit 10 at the time of recording is arranged on an extension line of the laser beam emitted from the pickup 5. . Further, the pickup 5 is subjected to focus servo, tracking servo, and threaded servo under the control of the servo circuit 12.

The ECC addition modulation circuit 13 adds an error correction code to the data D _IN supplied from an input signal processing circuit (not shown) and modulates the data D _IN to generate multi-valued digital phase modulation circuit 9 as recording data D _R0. Output to. The multi-level digital phase modulation circuit 9 shifts the rising and falling edges of the basic recording clock CLK minutely in a step-like manner in accordance with the recording data D _R0 to perform multi-level digital phase modulation, and the resulting phase modulation signal. D _R1 is supplied to the magnet drive circuit 10.

In the above-described structure, in the magneto-optical disk device 1, the information pit is formed by the heat of the laser light when recording the data. Therefore, the laser power is controlled by the pick-up 5 and the laser power control circuit 6 so as to keep the recording area at a constant temperature. At the same time, the external magnetic field generating coil 11 is controlled by the magnet drive circuit 10 in accordance with the phase modulation signal D _R1 output from the multilevel digital phase modulation circuit 9, whereby the rising and rising edges of the data to be recorded. An information bit is formed on the magneto-optical disk 2 by the magnetic field modulation signal corresponding to the downstream edge.

With respect to this recording principle, FIG. 2 shows an example in which the recording basic clock CLK is modulated into four values by the multilevel digital phase modulation circuit 9. First, the basic recording clock CLK (Fig. 2
(A)) is modulated by the multi-valued digital phase modulation circuit 9 that slightly changes the edge of the basic clock according to the data D _R0 to be recorded, and the phase modulation signal D _R1 (FIG. 2) is obtained.
(B)) is supplied to the magnet drive circuit 10. Further, as described above, the laser generates, for example, continuous constant power Pw so as to keep the recording area at a constant temperature (FIG. 2 (D)).

In this state, based on the phase modulation signal D _R1 , the external magnetic field generating coil 11 in the magnet drive circuit 10 is generated.
Is driven to generate an external magnetic field (FIG. 2C), and data is recorded. The external magnetic field is the strength of the magnetic field that allows the magnetic film of the magneto-optical disk 2 to be sufficiently magnetized.
In (C), it is assumed that the magneto-optical disk 2 is magnetized in the ⊚ direction by the symbol “+” and magnetized in the x direction by the symbol “−”.

Practically all possible pulse positions t = t
0, t1, t2, t3 and T / 2 + t0, T / 2 + t1
, T / 2 + t2, T / 2 + t3, the information pits are overlapped and written, as shown in FIG. 2E, at the boundary where the magnetization direction is reversed, that is, at the edge of the information pit, the edge is stepwise from the reference position. The digital recording can be performed by edge position modulation by giving a minute displacement according to the data to be recorded.

In such a magneto-optical recording method, the position of the edge having information is determined by the position of reversal of the modulation magnetic field while keeping the recording area at a constant temperature by the laser light. Therefore, overwriting can be performed with a normal magneto-optical disk without receiving thermal interference due to the position of the data before the data to be written. Since the recording method uses a magnetic field modulation method, overwriting can be realized with a magneto-optical disk having a simple structure, as compared with a light intensity modulation method capable of overwriting.

According to the above construction, the recording basic clock CLK which is synchronized with the reference clock previously recorded in the magneto-optical disk 2 and has the same frequency as the basic clock of the data D _R0 to be recorded is generated and recorded. Data D _R0
According to the above, a phase modulation signal D _{R1 in} which the phase of the recording basic clock CLK is slightly shifted is generated, and while irradiating laser light so that the recording area on the magneto-optical disk 2 has a constant temperature,
Since the external magnetic field is modulated according to the phase modulation signal D _R1 and the data D _R0 is recorded on the magneto-optical disc 2, when the data D _R0 is recorded by the edge position modulation of the information bit, Data can be recorded reliably with a simple configuration.

In the above-mentioned embodiment, the continuous constant power P is supplied from the laser power control circuit 6 during recording.
Although the case of generating w has been described, the recording power may be emitted in pulses like a pulse train. Further, in the above-mentioned embodiment, the case where the clock information is pre-recorded on the magneto-optical disk 2 by the pre-pit such as the embossed disk has been described, but not limited to the clock information, the tracking information, sector, address, absolute time, etc. The position information may be formed by embossed pits,
Further, the recording is not limited to the embossing, and pre-groove may be used for pre-recording on the magneto-optical disk.

Further, in the above-mentioned embodiments, the present invention has been described for the case where the edge position of the recording basic clock is shifted stepwise in accordance with the recording data and the magnetic field modulation recording is performed on the disk-shaped recording medium composed of the magneto-optical disk. But,
The shape of the recording medium is not limited to this, and it is suitable for wide application to a magneto-optical recording method and a magneto-optical recording apparatus for various magneto-optical recording media such as a card-shaped or tape-shaped recording medium.

[0024]

As described above, according to the present invention, the recording basic clock which is synchronized with the reference clock pre-recorded on the magneto-optical recording medium and which has the same frequency as the basic clock of the data to be recorded is generated, Generates a recording signal in which the positions of the rising and falling edges of the basic recording clock are minutely displaced stepwise from a predetermined reference position in accordance with the data to be recorded, and the recording area on the magneto-optical recording medium has a constant temperature. When the data is recorded by the edge position modulation of the information bit, the external magnetic field is modulated according to the recording signal and the data is recorded on the magneto-optical recording medium while irradiating the laser beam as described above. Thus, it is possible to realize a magneto-optical recording method and a magneto-optical recording device capable of surely recording with a simple configuration.

[Brief description of drawings]

FIG. 1 is a block diagram showing a magneto-optical disc device according to the magneto-optical recording method and the magneto-optical recording device of the present invention.

FIG. 2 is a timing chart for explaining a recording operation of the magneto-optical disk device of FIG.

FIG. 3 is a timing chart for explaining a high-density recording method by edge position modulation in a conventional magneto-optical disk.

4 is a timing chart for explaining a reproducing method of the magneto-optical disk recorded by the high density recording method of FIG.

[Explanation of symbols]

1 ... Magneto-optical disk device, 2 ... Magneto-optical disk, 3
...... Spindle servo circuit, 4 …… Spindle motor,
5 ... Pickup, 6 ... Laser power control circuit, 7 ... Demodulation / decoding circuit, 8 ... PLL circuit, 9 ...
Multi-valued digital phase modulation circuit, 10 ... Magnet drive circuit, 11 ... External magnetic field generating coil, 12 ... Servo circuit, 13 ... ECC addition modulation circuit.

Claims (2)

(57) [Claims] 1. A recording basic clock which is synchronized with a reference clock pre-recorded on a magneto-optical recording medium and which has the same frequency as the basic clock of the data to be recorded, is recorded according to the data to be recorded. Is the position of the rising and falling edges of the basic clock a predetermined reference position?
Then, a recording signal slightly displaced in a step-like manner is generated, and while irradiating laser light so that the recording area on the magneto-optical recording medium has a constant temperature, the external magnetic field is modulated according to the recording signal, A magneto-optical recording method characterized in that data is recorded on the magneto-optical recording medium. 2. A clock generation means for generating a recording basic clock having the same frequency as the basic clock of the data to be recorded, in synchronization with the reference clock pre-recorded on the magneto-optical recording medium, and to the data to be recorded. Depending on whether the positions of the rising and falling edges of the recording basic clock are the predetermined reference positions,
Recording signal generating means for generating a recording signal slightly displaced in a step-like manner, and an external magnetic field according to the recording signal while irradiating laser light so that the recording area on the magneto-optical recording medium has a constant temperature. A magneto-optical recording device comprising: a magneto-optical recording unit that modulates and records the data in the magneto-optical recording medium.