JPH04117650A - Magneto-optical recording and reproducing method - Google Patents

Abstract

PURPOSE:To surely read out the signals of a preformat part in a recording or erasing mode by making an optical power stronger than a normal reproducing power at the time of reproducing the preformat part, and increasing the S/N of detected prepit signals. CONSTITUTION:When the preformat part is reproduced in the recording or erasing mode by using a magneto-optical recording medium 3 having a perpendicular magnetic anisotropy, the preformat part is irradiated with a high power obtained by making a light emitting power stronger than the reproducing power in the reproducing mode, and the preformat part is reproduced by the reflected lights. Thus, the noise of a semiconductor laser (LD) 7 is relatively reduced with the increase of the power, and the prepit signals are taken out as the change of the reflectance, so that the signal intensity can be large with the increase of the power, and the S/N can be increased. Thus, prepit information with little error rate can be obtained.

Description

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

[Prior Art] In recent years, optical systems have been developed that can optically record information and reproduce recorded information by focusing laser light and irradiating it onto a recording medium instead of using a magnetic head. Information recording and reproducing equipment was put into practical use.

In the above-mentioned optical information recording device, since the magneto-optical recording/reproducing device can rewrite recorded information, it is expected that it will be widely used in the future in place of a magnetic head type recording/reproducing device such as a hard disk device.

In the above-mentioned magneto-optical recording/reproducing device, a disc-shaped recording medium (hereinafter abbreviated as magneto-optical disk) is used as a magneto-optical recording body provided with a record having perpendicular magnetic circumferentiality, and this magneto-optical disk stores information. The track to be recorded is divided into a plurality of sectors, and recording is performed in units of sectors.

Therefore, address information indicating the track number or sector number is required at the beginning of each sector. A preformat section is provided in which these information and VFO signals are preformatted on the magneto-optical disk (for example, "Optical Disk Technology" Radio Gijutsu Sha P, 224-P.
, 230).

The signal of this preformat section is formed by uneven pre-pits. After this pre-pit signal, information is recorded using a magneto-optical signal.

Therefore, in a magneto-optical recording/reproducing device (hereinafter abbreviated as magneto-optical disk device), it is necessary to detect both the change in the intensity of reflected light due to the unevenness and the change in the plane of polarization due to the Kerr effect.

FIGS. 10(a), 10(b), and 10(c) show the laser power in erasing mode, recording mode, and reproducing mode in the conventional example.

As can be seen from this figure (C), in the reproduction mode, irradiation is performed at a constant power at a low level, and the prepit signal and the magneto-optical signal are detected by the reflected light from the magneto-optical disk.

On the other hand, in the erase and record mode, the preformat area is irradiated with the same power as the playback mode, the pre-pit signal is detected, and the data area is erased or recorded with a high level of power. The power is at a high level only in the case of recording, and the power is at a low level when no recording light is emitted, as in the playback mode.

Generally, when a semicircular laser (LD) is used as a laser light source for a magneto-optical disk, reflected light from the magneto-optical disk returns to the LD, generating noise.

This noise is defined as relative noise intensity (RIN), and as shown in FIG. 11, the value of RIN increases as the laser power decreases. When the noise increases, the reproduced signal deteriorates, causing reading errors. Increasing the laser power in the reproduction mode reduces noise, but the first
As shown in Figure 2, the Kerr rotation angle of the magneto-optical signal decreases as the temperature rises, and the power cannot be increased more than necessary because there is a risk of erasing information.

To deal with this, as shown in Japanese Patent Publication No. 59-9086, high frequency superposition is used to reduce the noise in the reproduction mode, so that it is not necessary to increase the laser power during reading.

In other words, in the reproduction mode shown in FIG. 10(C), since signals are constantly read, high frequency superimposition is always turned on and reproduction is performed at a constant low level power.

On the other hand, in the erasing or recording mode shown in FIGS. 10(a) and 10(b), when reading the recorded information in the preformat section, the level is set to low and the high frequency superimposition is turned off.
When erasing or recording in the data section, the high frequency superimposition is turned off and the power is switched to a high level.

[Problems to be Solved by the Invention] However, when recording or erasing is performed with high frequency superimposition applied, the peak power of light emission increases and exceeds the rated output.

For this reason, as shown in Japanese Patent Laid-Open No. 63-90037, it is necessary to stop the high frequency superimposition when recording or erasing data in the data section.

Therefore, as shown in FIGS. 10(a) and (b), in the erasure or recording mode, the preformat area (when reading) and the data area (when erasing or recording) are switched in time. Therefore, high-frequency superposition must be switched at high speed.

When high-frequency superposition is turned on by this switching, it takes time for the high-frequency superposition to reach the specified value (rise), and the S/N of the signal portion reproduced within this time will decrease. It will end up being put away. For this reason, the switching circuit must be refined to have a good start-up, resulting in a complicated circuit configuration and the need to use expensive elements, causing problems.

In addition, there are other problems as follows.

For example, in order to read the information in the preformat section in the recording or erasing mode, when reproduction is performed with the power of the reproduction mode (referred to as reproduction power or read power), as shown in FIG. The reflected light from the incident light R1 or R has its plane of polarization rotated by an angle θ in the child direction or in one direction with respect to the incident linearly polarized light depending on the direction of magnetization.
It becomes 1'. And in the preformat section,
In addition to this, changes in reflectance due to unevenness are added. Therefore, when detecting a pre-pit signal using the same optical system used for detecting a magneto-optical signal, the light passes through an analyzer whose transmission direction is set at an appropriate angle with respect to the direction of the incident linearly polarized light, as shown in Figure 13. When a pre-pit signal is obtained from the output, the amplitude of the pre-pit signal changes between 11-I2 to II' to I2' depending on the direction of magnetization of a part of the magnetized film of the BRIFOMATSU 1, and a constant amplitude is obtained.

In this way, when the amplitude changes depending on the direction of magnetization, 2
When attempting to obtain pre-pit information by digitization, it becomes difficult to set a threshold for binarization, resulting in a high error rate.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a magneto-optical recording and reproducing method that can reliably read signals in a preformat section even in recording or erasing mode.

[Means and effects for solving the problems] In the present invention, at least when reproducing a preformatted section in recording or erasing mode, the light emitting power is irradiated with a high power higher than the reproducing power in the reproducing mode. The preformat section is played back using reflected light.

By doing this, the noise of the LD becomes relatively smaller as the power increases, as shown in Figure 11, and since the pre-pit signal is extracted as a change in reflectance, the signal strength increases as the power increases. becomes larger, and the S/N
It is possible to obtain pre-pit information with a low error rate.

Also, when the preformat area is irradiated with the recording light emission power or erasing light emission power in the recording mode or erasing mode,
The temperature rise caused by this irradiation erases the magnetization of the preformatted part, and the reflected light does not undergo any rotation of the plane of polarization, so it is possible to reproduce reproduced signals with fewer errors without being affected by the disadvantageous effects shown in Figure 13. Obtainable.

[Example〕 Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIGS. 1 to 4 relate to a first embodiment of the present invention.
The figure shows the laser power in erasing mode, recording mode and reproduction mode in the method of the first embodiment, and Fig. 2 shows the laser power in the method of the first embodiment.
The main parts of the recording and reproducing apparatus according to the embodiment are shown, FIG. 3 shows the intensity of the pre-pit signal and the magneto-optical signal with respect to the laser power, and FIG. 4 shows that a reproducing signal that is not affected by the Kerr rotation angle can be obtained. show.

As shown in FIG. 2, a magneto-optical disk device according to the method of the first embodiment! 1, a magneto-optical pickup 4 is disposed facing one surface of a magneto-optical disk 3 which is rotationally driven by a spindle motor 2, and an electromagnet 5 for applying a bias magnetic field is disposed opposite the other surface. There is.

The magneto-optical pickup 4 houses an LD 7, and the linearly polarized laser light from the LD 7 is converted into a non-diffusing light beam by a collimator lens 8, then enters a first beam splitter 9, and is transmitted through this beam splitter 9. The emitted light is focused by an objective lens 11 and directed onto a magneto-optical disk 3.
is irradiated.

The light reflected by this magneto-optical disk 3 is transmitted to the objective lens 1
The light is focused by the beam splitter 1 and proceeds to the first beam splitter 9, and the light reflected by the beam splitter 9 is incident on the second beam splitter 12.

The light transmitted through this beam splitter 12 is incident on a critical angle prism 13, and the light reflected on the slope of this critical angle prism 13 is received by a four-split photodetector 14.

On the other hand, the light reflected by the second beam splitter 12 is
The polarization direction is rotated by 45° by the λ/2 plate 15, and the light transmitted through the λ/2 plate 15 is sent to the polarizing beam splitter 1.
6, P! The Ji light component is transmitted, and the S polarized light component is reflected and received by photodetectors 17a and 17b, respectively. This device 1 uses a differential optical system to obtain magneto-optical signals.

The signal photoelectrically converted by the 4-split photodetector 14 is input to the matrix circuit 21, where addition and subtraction are performed.
A track error signal TE, focus error signal FE, and summation signal SU are generated. Track error signal TE
The focus error signal FE and the focus error signal FE are respectively input to dividers 22 and 23 together with the sum signal SU, and are divided by the sum signal SU to obtain a standardized track error signal NT.
E, NFE is generated. In other words, the track error signal TE and the focus error signal FE are divided by the sum signal SU proportional to the total light intensity of the light beam, so that a standardized track error signal NTE and a focus error signal that do not depend on the intensity of the light beam are obtained. Become an NFE.

The standardized track error signal NTE is sent to switch 2.
5. The light beam is supplied to the tracking coil 28 that refines the lens actuator through the phase compensation circuit 26 and the servo amplifier 27, and in the tracking servo state when this switch 25 is turned on, the spot of the light beam irradiated on the magneto-optical disk 3 will now follow the truck.

The standardized focus error signal NFE is supplied to the focusing coil 32 via the phase compensation circuit 29 and servo amplifier 31, and the spot of the light beam irradiated onto the magneto-optical disk 3 is maintained in a focused state.

On the other hand, the signal output detected by the pair of photodetectors 17a and 17b is input to a differential amplifier 33 for detecting magneto-optical signals.
A magneto-optical signal PM is obtained by differential output of the two signals. or,
By adding the two signals in an adder 34, a bleep I-signal Pr (is obtained).

The LD 7 is driven by a current supplied from the LD driver 35, and the current output from the LD driver 35 changes according to the signal passed through the OR gate 36.

The OR gate 36 is configured to receive an erase signal ES output during the erase mode and a recording signal WS output during the record mode.

Furthermore, the LD 7 includes a high frequency superimposition module (hereinafter referred to as HF).
When 37 (abbreviated as M) is turned on, the LD driver 3
The high frequency signal is superimposed on the current from 5. For example, this HFM37 is turned ON by the reproduction mode signal RMS which becomes "H" in the reproduction mode, and is always OFF in other than this reproduction mode, that is, in the recording mode and the erasing mode.
is maintained.

Therefore, in the LD 7, a high frequency signal current is superimposed on the reproduction light emission current from the LD driver 35 only in the reproduction mode, and in the erase mode and the recording mode, the LD 7 is driven (laser emission) only by the current from the LD driver 35. ).

The above erase signal ES is generated when the drive current of the LD driver 35 is L.
This is a signal that causes D7 to emit light with erase light power,
LD driver 3 when this erase signal ES is not output
The drive current is made larger than that of No.5.

In this first embodiment, the erase signal ES is constant, and therefore the laser power of the LD 7 is adjusted so that the irradiation positions on the magneto-optical disk 3 are the data section, the preformat section, and the data section, as shown in FIG. 1(a). It will remain constant even if it changes. As mentioned above, the HFM37 is always OFF in this erase mode, and as in the conventional example shown in FIG. 10(a), it is ONL in the preformat section and OFF in the data section.
There is no need for high-speed switching to F.

Further, the recording signal WS is such that in the data section, the power of the LD 7 is switched in a pulsed manner to the recording light emission power level and the reproduction light emission power level in accordance with the information to be recorded, as shown in FIG. 1(b). and a drive signal that causes the preformat section to emit light at the recording light emission power level.

Even in this recording mode, when the light spot scans the preformat area, it is held in the recording light emitting power,
In addition, the HFM 37 is always kept OFF, so there is no need for high-speed switching such that it is ONL in the first to third sections and OFF in the data section.

In the recording mode and erasing mode, the switch 38 constituting the bias magnetic field means is switched, and the current flowing from the constant current source 39 to the electromagnet 5 has opposite polarity in both modes. Therefore, the portion irradiated with the beam spot by recording light emission in the recording mode can be magnetized in the opposite direction to the direction magnetized in the erasing mode.

According to this first embodiment, as shown in FIG. 1(a), even in the erase mode, the power of D7 is kept constant in both erasing the data section and reproducing the preformat section. There is no need for control to change the
The configuration of the LD control system (LD drive system) becomes simple.

Further, even in the recording mode, even if the irradiation position changes from the data area to the preformat area, the recording light emission power is maintained, so it is only necessary to control the peak power.

Also, high frequency superimposition is turned on in the preformat section and data section both during erase mode and during recording mode.

Since switching to turn off is not required, a high-speed switching circuit can be made unnecessary.

In addition, the pre-pit reproduction signal and the magneto-optical reproduction signal (Kerr rotation angle signal) with respect to the laser power are as shown in Fig. 3, and the pre-pit reproduction signal shown by the solid line increases linearly in proportion to the power, while the double-dashed line In the conventional example, the magneto-optical reproduction signal shown by increases almost in proportion to the power at low levels, but then deviates greatly from this linear characteristic and gradually decreases, becoming O as the magnetization disappears.
Since the preformat section is also reproduced with the reproduction power in the low level region where the magneto-optical signal increases almost in proportion to the power, the pre-pit reproduction signal obtained through the adder 34 shown in FIG. (It is assumed that Ia and Tb are only due to the difference in reflectance due to the unevenness and do not depend on the Kerr rotation angle.) To obtain information corresponding to the unevenness from this reproduced signal, These values■
a.

Binarization is performed using a threshold value Is between Ib.

On the other hand, as in the first embodiment, when irradiation is performed at a high power near the level at which the Kerr rotation angle disappears, the pre-pit reproduction signals obtained are as shown in Ia' and Ib' in FIG. For example, the threshold value in this case can be set to Is'.

Therefore, even if the relative noise intensity RIN of LD7 does not depend on the laser power, the pre-pit reproduction signal in erase mode or recording mode will change by the amount (
The S/N is improved by Ia'/Ia) (compared to the case where it is not increased). In other words, the noise margin becomes sufficiently large, so
Misreading of pre-pit information in erase mode or recording mode is eliminated.

By the way, as shown in FIG. 11, the LD exhibits a characteristic that the RIN decreases as the laser power increases, so increasing the laser power when reproducing the preformat portion further increases the above-mentioned S/N improvement. It turns out.

Therefore, a highly reliable device can be realized.

Further, in this first embodiment, the S/N of the standardized track error signal NTE and focus error signal NFE is also improved by increasing the laser power when reproducing the preformatted portion in the erase or record mode. In other words, in the conventional example, the laser power is at a low level when scanning a preformatted area even in erase mode and recording mode, so tracking control and focusing control (erase light emitting power or recording (from the state controlled by light emitting power)
In contrast, according to the method of the first embodiment, tracking control and focusing control with good S/N ratio can be maintained even while scanning the preformat area.

Therefore, vibration resistance characteristics and the like can also be improved.

Note that if, for example, only one of the photodetectors 17a or 17b in FIG. 2 is used as the detection system for obtaining the pre-pit signal, or if an equivalent detection system is used, the power of the LD 7 may be reduced when reproducing the preformat section. If the reproduction power is set to the erasing (or recording) emission power, problems as shown in FIG. 13 will occur, but even in the case of this detection system, if the method of the first embodiment is applied and the erasing (or recording) emission power is set, the pre-pit reproduction signal obtained As shown in FIG. 4, it is possible to obtain signals with very large amplitudes Ia and Ib, a small RIN, and a good S/N ratio without being affected by the magnetic Kerr effect.

Therefore, the first embodiment is also effective even if a detection system is used that directly obtains a prepit signal from one of the photodetectors 17a or 17b without using the adder 34 in FIG.

Further, according to the first embodiment, high-speed switching of the HFM 37 is unnecessary, so that costs can be reduced.

FIG. 5 shows the main parts of the optical system of a magneto-optical disk device according to a second embodiment of the present invention.

This device uses two light sources to perform sword atomization so that recorded data can be verified immediately after recording.

In the DBF format using the sample servo method, it is necessary to detect the recording start timing using a pre-pit signal. Then, the pick-up 41 is adopted.

That is, the recording/erasing LD 42 is an LD that can emit light with high power, and emits a laser beam having a wavelength of, for example, 830 nm. This laser light passes through a collimator lens 43 and enters a beam splitter 44 . The light beam transmitted through this beam splitter 44 is transmitted to a dichroic mirror 45.
The light passes through, is focused by an objective lens 46, and is irradiated onto a magneto-optical disk 47.

The light reflected by the magneto-optical disk 47 passes through an objective lens 46 and a dichroic mirror 45 to a beam splitter 44, and the light reflected by this beam splitter 44 is received by a pre-pit detection photodetector 48. .

On the other hand, for example, the wavelength emitted from the reproduction LD 51 is 78
The low power laser beam of 0 na+ is collimated by the collimator lens 5.
The light beam that passes through the beam splitter 53 is reflected by the reflection mirror 54 and then enters the dichroic mirror 45.

This dichroic mirror 45 has the characteristic of transmitting light with a wavelength of 830 nm and reflecting light with a wavelength of 780 nm, in this case, the wavelength of 780 nm.
The n- light beam is reflected, focused by the objective lens 46, and irradiated onto the magneto-optical disk 47.

The light reflected by the magneto-optical disk 47 passes through the objective lens 46, the dichroic mirror 45, and the mirror 54, and then proceeds to the beam splitter 53.
A servo signal and a magneto-optical signal (and a pre-pit signal) are obtained from the light reflected by the mirror.

The optical axis of the optical system on the recording/erasing LD42 side and the reproduction L
Since the optical axis of the optical system on the D51 side does not coincide with the optical axis of the optical system on the D51 side, as shown in FIG. It is set to be more upstream in the track direction.

In other words, immediately after recording is performed with the recording spot, the reproduction spot illuminates the recorded data portion so that the data in that data portion can be read and verified.

Note that an electromagnet 55 is disposed opposite to the surface of the magneto-optical disk 47 opposite to the surface facing the pickup 41.

In this pickup 41, the recording/erasing LD4
In the erase mode, No. 2 continuously emits light with high power as in No. 1 [M(a). Further, in the recording mode, as shown in FIG. 1(b), the preformat section emits light continuously at high power, and the data section emits light in a pulsed manner in accordance with the recording signal.

In the reproducing mode, the reproducing LD 51 continuously emits light at low power as shown in FIG. 1(C).

In addition, since this pickup 41 does not have HFM,
The high frequency superimposition in FIGS. 1(a), (b), and (c) is all OFF.

This is because the playback LD 51 is used only for continuous light emission at low power, so it is possible to use a low-noise LD used for playback-only devices such as video discs. In other words, an LD that oscillates in multiple modes with low power.
There is no need to use HF M. ) This second embodiment operates in erase mode and recording mode in the same manner as in the first embodiment.
Similar to the embodiment, and also in the playback mode, f(F
Signal reproduction with good S/N can be performed without using M.

FIG. 7 shows a schematic configuration of a magnetic field modulation type magneto-optical disk device 61 according to a third embodiment of the present invention.

A pickup 63 is arranged opposite to one surface of the magneto-optical disk 62, and an electromagnet 64 for applying a magnetic field is arranged opposite to the other surface.

The pickup 63 houses an LD 64, and this L
The laser beam of D64 hits a collimator lens 65, a beam splitter 66, an objective lens 67, and a magneto-optical disk 62.
is focused and irradiated.

The light reflected by the magneto-optical disk 62 passes through the objective lens 6.
7 to a beam splitter 66, and a servo signal, a magneto-optical signal, and a prepit signal are obtained from the light reflected by this beam splitter 66 (for example, the same detection system as shown in FIG. 2 can be used). .

The LD 64 emits light with the driving current from the LD driver 68, and emits light in the reproduction mode by being superimposed with a high frequency signal from the HFM 69 which is turned on by the reproduction mode signal RMS only in this mode.

A recording mode signal WMS that becomes 'H' in the recording mode is input to the LD driver 68, and when this signal becomes 'H', the LD 64 emits light with high power.In addition, in this magnetic field modulation method, data recording When performing this, one of the features is that it is possible to overwrite without erasing in erase mode.

The LD 64 continuously emits light at high power during the recording mode, and continuously emits light at low power during the playback mode.

On the other hand, the electromagnet 64 is supplied with a drive current from a modulation drive circuit (abbreviated as a modulation circuit) 71 that outputs a drive IJJJ current whose polarity changes according to the binarized recording signal.

In this third embodiment, the L
D power, magnetic field, and HFM69(7) ON and OF are controlled as shown in FIGS. 8(a), (b), and (c).

That is, in the reproduction mode, the LD power is at a low level, no driving current flows through the electromagnet 64, the magnetic field H is O, and the HF
M69 is always turned on.

On the other hand, in the recording mode, the LD power is always kept at a constant high power value, and the electromagnet 64 is supplied with a drive current according to the binarization level of the recording signal, so that the magnetic field is adjusted according to the polarity of the drive current. becomes +Ha or -Ha. Also, H
FM 69 is always OFF.

1. The magnetic field H is controlled to be, for example, Ha in the preformat section (of course, it may be set to +Ha).

Therefore, when reproducing the preformat section in the reproduction mode, the magnetization direction of the preformat section is magnetized in one direction, so the amplitude is not affected by the magnetization direction. Similar to the example.

In each of the embodiments described above, when reading information from the preformat section in recording mode or erasing mode, the light emitting power is made equal to the recording or erasing light emitting power.

However, the present invention is not limited to these.
For example, the power may be greater than the reproduction power in the reproduction mode and less than the recording or erasing power.

For example, in the RIN characteristics with respect to the LD power shown in FIG. 11, if a certain upper limit value R of the relative strength desired from the detection system used is determined, then if the power is set to a power value of 2 or more corresponding to this value R, then Good. However, if the effect of improving the S/N by increasing the LD power is also taken into consideration, a smaller LD power will be sufficient.

Furthermore, in each of the above-described embodiments, the playback mode is the same as the conventional one, but the drive current from the LD driver may be increased in the preformat section as shown in FIG. 9, for example. If the drive current from the LD driver is increased while the HFM is turned on,
(Set the value to a value that can be maintained below the maximum rating of the LD).

By doing this, it is possible to improve the S/N when reading the preformat section in the playback mode and controlling the servo.
It is also unnecessary to switch the HFM at high speeds.

Furthermore, if a means of high-speed switching is used,
Even in the playback mode, playback may be performed by setting the recording light emission power or erasing light emission power in the preformat section and turning off the HFM.

Note that each of the embodiments described above may be partially adapted.

[Effects of the Invention] As described above, according to the present invention, when reproducing a preformat section, the optical power is made larger than the normal reproduction power, thereby increasing the S/N of the detected pre-pit signal. Therefore, even when using high frequency superimposition means,
The control can be significantly simplified, and errors in reading the pre-pit I signal and the like can be reduced. It also contributes to high reliability and low cost of the device.

[Brief explanation of drawings]

FIGS. 1 to 4 relate to the first embodiment of the present invention.
The figure shows the control state of laser power in each mode and the ON state of high frequency superimposition according to the first embodiment. An explanatory diagram that does not show the OFF control state, FIG. 2 is a configuration diagram of the device used in the first embodiment, FIG. 3 is a characteristic diagram showing the intensity of the pre-pit reproduction signal and magneto-optical reproduction signal with respect to laser power, and FIG. 4 is an explanatory diagram showing that a pre-pit reproduction signal that is not affected by the Kerr rotation angle is obtained; FIGS. 5 and 6 relate to the second embodiment of the present invention; and FIG. 5 shows the light used in the second embodiment. FIG. 6 is an explanatory diagram showing the positional relationship between the recording optical spot and the reproducing optical spot, and FIGS. 7 and 8 are diagrams showing the main parts of the optical system of the magnetic pickup.
Regarding the embodiment, FIG. 7 is a schematic configuration diagram of the apparatus used in the third embodiment, FIG. 8 is an explanatory diagram showing the laser power etc. controlled according to the third embodiment, and FIG. 9 is a diagram showing the structure of the apparatus used in the third embodiment. An explanatory diagram showing how the drive current is controlled in the reproduction mode according to the fourth embodiment, FIG. 10 is an explanatory diagram showing how the control is performed in the conventional example, and FIG.
:Characteristic diagram showing the outline of intensity characteristics, Figure 12 is a characteristic diagram showing the magnitude of Kerr rotation angle with respect to laser power, Figure 13
The figure is an explanatory diagram showing that the prepit signal obtained in the conventional example is influenced by the car rotation angle. 1... Magneto-optical disk device 3... Magneto-optical disk 4... Magneto-optical pickup 5... Electromagnet 7...
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Claims (1)

[Scope of Claims] 1. In a magneto-optical recording device that optically performs recording and reproduction using a magneto-optical recording medium having perpendicular magnetic anisotropy, a preformatted part of the magneto-optical recording medium is preformatted. A magneto-optical recording and reproducing method, characterized in that optical power for reading information is set to be greater than optical power irradiated onto the magneto-optical recording medium when reproducing magnetically recorded information. 2. The magneto-optical recording according to claim 1, wherein in the recording mode or the erasing mode, the optical power irradiated to the preformat section is made almost the same as the recording or erasing light emission power, so that magnetization is lost. How to play. 3. In a magneto-optical recording/reproducing device that records data by continuously irradiating light onto a magneto-optical recording medium and at the same time modulating an external magnetic field according to the information to be recorded, it is possible to continuously record multiple sectors. When recording, a magneto-optical recording and reproducing method is characterized in that the preformat area is irradiated with the same recording light emitting power as the data area, and an external magnetic field is applied in one direction.