JP2000276734A - Method and device for detecting recording laser power, recording laser power control method, and recording device and recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make settable a recording laser power by recording a reference signal for examination of a predetermined pattern on a recording medium while changing the laser power, obtaining the reproducing signal of the recorded reference signal for examination and detecting the change information of the laser power as information on a change in a phase difference from the examination reference signal. SOLUTION: An APC area reference signal generating circuit 17 outputs a reference signal for examination in a fixed cycle and a system controller 10 writes a pattern corresponding to the reference signal for examination on the APC area of a magneto- optical disk 1 while controlling the output laser power of the semiconductor layer of an optical pickup 4 through a laser power control circuit 6. A phase difference detecting circuit 23 compares the phase of the reference signal for examination with the reproducing signal of the recorded reference signal for examination, supplies an exclusive OR output to a proper power determining circuit 24, sends step information to be the optimum phase difference to a system controller 10 and controls the optimum laser power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of forming a next recording mark such that a recording mark which alternates between two states is partially overlapped with a previous recording mark, such as a magnetic field modulation recording method. Method for detecting a recording laser power used in a recording method for performing recording on a recording medium, and a detecting device, a recording laser power control method, and a method thereof,
The present invention relates to a recording device and a recording / reproducing device using the device.

[0002]

2. Description of the Related Art There are a light modulation recording method and a magnetic field modulation recording method as a method of recording a mark on a magneto-optical disk.

In the light modulation recording method, before recording, the direction of magnetization of the recording layer of the magneto-optical disk is aligned, and at the time of recording, a portion irradiated with laser light to raise the Curie temperature is irradiated with laser light. The recording is performed by reversing the direction of magnetization by using a magnetic head disposed at a position facing the portion and having the opposite polarity to the direction of magnetization of the recording layer.

For example, first, the recording layer of the entire disc is set to N
Then, an external magnetic field generated by the magnetic head is set to the S pole, and a laser beam corresponding to the digital signal is applied to a portion facing the magnetic head. Then, the portion of the signal “0”, for example, which has risen to the Curie temperature by the laser beam, is inverted to the S pole. As a result, a binary digital signal of “1” and “0” is recorded.

On the other hand, in the magnetic field modulation recording method, at the time of recording,
While continuously irradiating the recording medium with the laser beam to warm the recording layer to the Curie temperature, a recording signal is supplied to the magnetic head, and the N pole and the S pole are alternately recorded on the recording layer. It is a method. In this case, in the magnetic field modulation recording method, unlike the light modulation recording method, the N-pole area and the S-pole area as recording marks are symmetrical with each other in a state where they overlap a part of a previously recorded mark. It can be formed well.

The above-described magnetic field modulation recording method is superior to the light modulation recording method in that overwriting can be performed, minute marks can be recorded, and recording marks are formed with high symmetry. And, due to the formation of the recording mark with good symmetry, the magnetic field modulation recording method has a very wide recording power margin.

However, as the recording track density increases as the density of the optical disk increases, the upper limit of the recording power is determined by not destroying the data of the adjacent track rather than recording the mark with high quality. As the number of recording laser powers is becoming restricted, it is important to set the optimum value of the recording laser power.

[0008]

By the way, in optical modulation recording, the laser power value where the N and S recording marks have the best symmetry naturally has good jitter of the reproduced waveform, which is the optimum recording laser power. Value. Therefore, in the optical modulation recording method, the optimum recording laser power is set by detecting the symmetry of a recording mark from its reproduction signal.

However, as described above, in magnetic field modulation recording, if the recording laser power is a certain power or more, the symmetry remains good. Was difficult to get.

This will be described with reference to FIGS. Normally, an APC (auto power control) area is provided on the disk separately from the data writing area, and the laser power is set in that area.

Normally, in the optical modulation recording system, in order to obtain the optimum recording laser power, recording and reproduction are actually performed on the recording medium while changing the recording laser power, and the asymmetry of the reproduction waveform of the recorded mark is examined. Select the recording laser power so that a signal with appropriate symmetry is reproduced,
This is the optimum recording laser power value. This will be briefly described with reference to FIG.

FIG. 4 shows a change in the recording power in the APC area due to the optical modulation recording and a change in the reproduction RF signal accompanying the change in the recording power.

In a state where the magnetization direction of the recording medium is aligned in one direction in advance (erasing state), as shown in FIG.
While sequentially changing the recording laser power value in a step-up manner, using a magnetic head, as shown in FIG.
While applying an external magnetic field in the + Hw direction, a recording laser pulse having a duty of 50% as shown in FIG. Then, as shown in FIG. 4D, a mark M whose size changes according to the recording laser power value is recorded. FIG. 4D shows an example of recording on a land, but the recording track may be a groove.

When this recorded mark is reproduced, FIG.
When the recording laser power is a low value, the ratio of exceeding the 0 level is small, and when the recording laser power is an appropriate laser power value, the reproduction RF signal exceeds the 0 level at half the ratio and the recording laser power is high. At the time of the value, the ratio exceeding the 0 level increases. In this manner, a change in the reproduction signal according to the recording laser power value is detected as a signal asymmetry state.

However, in the case of recording by the magnetic field modulation recording method, even if the recording laser power is changed in principle, no significant waveform asymmetry appears. This will be briefly described with reference to FIG.

FIG. 5 shows a change in the recording laser power in the APC area according to the magnetic field modulation recording method, and the accompanying reproduction R.
It shows how the F signal changes. In the case of the magnetic field modulation recording method, as shown in FIG. 5A, while changing the recording laser power value, the recording external magnetic field by the magnetic head is changed to + Hw as shown in FIG.
And -Hw in both directions at a duty of 50%. For example, as shown in FIG. 5B, a laser is used as a recording laser pulse in synchronization with a recording external magnetic field (FIG. 5C). Irradiation.

Then, as shown in FIG. 5D, a mark M corresponding to data is recorded while partially overwriting a previously recorded mark. When the recording mark M is reproduced, as shown in FIG. 5 (E), when the recording laser power is low, the amplitude of the reproduction signal is small, and when the recording laser power is appropriate, the amplitude has an appropriate level. The ratio exceeding the zero level is also about half. However, even when the recording laser power is a high value, the amplitude does not increase so much, and the ratio exceeding the zero level remains about half.

As described above, in the case of the magnetic field modulation recording method, a change in the reproduction signal corresponding to a change in the recording laser power value is not detected as the symmetry of the signal. Therefore, in the case of the magnetic field modulation recording method, the appropriate laser power for increasing the recording track density cannot be appropriately set in view of the symmetry of the reproduced RF signal.

Therefore, as described above, the upper limit of the recording laser power when the recording track density is increased is limited by not destroying the data of the adjacent track, rather than recording the mark with high quality. From two adjacent
It is necessary to record a mark on a track or a higher track while changing the recording laser power as described above, and to set an optimum recording laser power using a reproduction signal from the recording track.

For example, a signal is recorded on a certain track TA, and then a signal is recorded on tracks on both sides of the recording track TA. Then, a signal is reproduced from the track TA, and it is monitored that the data on the track TA is not destroyed by recording the tracks on both sides of the track TA. This operation is performed by changing the recording laser power to set the optimum recording laser power.

For this reason, it is necessary to use three adjacent recording tracks as the APC area, so that the APC area is required to be wide, and it is necessary to record or reproduce the three tracks. There is a drawback that it takes time to set.

According to the present invention, in consideration of the above points, two states are alternately formed as recording marks as in a magnetic field modulation recording system, and the recording marks are partially overlapped with the preceding recording mark.
In the recording method for forming the next recording mark, the value of the recording laser power is appropriately detected and extended,
Provided is a method and apparatus capable of easily setting an optimum recording laser power.

[0023]

In order to solve the above-mentioned problems, according to the present invention, a laser is irradiated onto a recording medium to form recording marks which can take two states alternately in the two states. A recording laser power detection method for use in a recording method in which recording is performed on a recording medium by forming a next recording mark in a state where the recording mark partially overlaps with a recording mark of a predetermined pattern. The signal is recorded on the recording medium while changing the recording laser power, a reproduced signal of the recorded inspection reference signal is obtained from the recording medium, and the inspection reference signal,
As information of a change in a phase difference between the read signal of the inspection reference signal and the reproduction signal at each value of the recording laser power,
A method for detecting a recording laser power, comprising detecting information on a change in the recording laser power.

According to the present invention, a change in the value of the recording laser power is detected as a phase difference between the recording mark pattern and its reproduction signal. This phase difference is, as described below,
This parameter changes according to the change in the recording laser power.

Therefore, by determining the optimum recording laser power phase difference as a value corresponding to the optimum recording laser power, the laser power value corresponding to the optimum recording laser power value is determined. Can be set easily.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a recording laser power detecting method according to the present invention will be described below together with an embodiment of a recording / reproducing apparatus to which the method is applied, with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration of an embodiment of a recording / reproducing apparatus using a recording laser power control system according to the present invention. The recording / reproducing apparatus according to the embodiment shown in FIG. 1 performs recording on a magneto-optical disk by a magnetic field modulation recording method.

In FIG. 1, the magneto-optical disk 1 is rotated at a specified rotational speed by controlling the driving of a spindle motor 3 by a spindle servo circuit 2.

The optical pickup 4 includes a semiconductor laser (not shown) as a laser light source, and is slidable in the radial direction of the magneto-optical disk 1. The position of the optical pickup 4 in the radial direction of the magneto-optical disk 1, that is, the write / read position with respect to the magneto-optical disk 1, is a predetermined position controlled by the thread servo circuit 5 under the control of the system controller 10. .

In order to control the position of the optical pickup 4, the optical pickup 4 reads out, for example, a track address recorded on the magneto-optical disk 1 as pits having irregularities as a light intensity signal (PITRF signal), and reads the P address.
The ITRF signal is input to the address decoding circuit 9.

The address decoding circuit 9 decodes track address information and the like recorded on the magneto-optical disk 1, and stores the position and address information in the system controller 1.
Give to 0. The system controller 10 writes data at a desired position on the magneto-optical disk 1 based on the position and address information, and outputs a control signal of the desired position to the thread servo circuit 5 and other circuits.

The laser power of the semiconductor laser of the optical pickup 4 is controlled by a laser power control circuit 6 so that the output laser power becomes a predetermined value.
The laser power at the time of recording is optimally set as described later, and the semiconductor laser is drive-controlled by the laser power control circuit 6 so as to emit the laser at the set recording laser power.

An external magnetic field generating coil (magnetic head) 7 is provided at a position opposite to the optical pickup 4 with respect to the magneto-optical disk 1 and on an extension of the laser beam emitted from the optical pickup 4. . The external magnetic field generating coil 7 is driven by a magnet drive circuit 8.

Since the present invention is not directly related to the present invention, the tracking servo system is omitted in FIG. 1 for simplicity of explanation.

Next, the flow of data when data is normally recorded and reproduced will be briefly described with reference to FIG.

First, an error correction code is added to the input recording data by the ECC adding circuit 11 and, for example, EF suitable for recording on the optical disk by the modulation circuit 12 is used.
M (Eight-Fourteen Modulati
on) Modulation is performed. The modulated data is input to the magnet drive circuit 8 through the selector 13. The magnet drive circuit 8 drives the external magnetic field generating coil 7 according to the modulation data. This allows
The external magnetic field generating coil 7 includes +,
A negative recording magnetic field is generated.

At the same time, the system controller 10
Sets the power to the laser power control circuit 6 so that the laser beam emitted from the semiconductor laser of the optical pickup becomes the recording power (laser power at the time of recording). The recording power at this time is an optimum recording laser power value obtained in advance as described later.

As described above, the recording mark corresponding to the polarity of the magnetic field generated by the external magnetic field generating coil 7 is formed on the magneto-optical disk 1.
Formed on top.

When reproducing data from a magneto-optical disk on which marks have been recorded as described above, first, a magneto-optical signal (MORF signal) is read from a recording track (for example, a land) by the optical pickup 4. The read magneto-optical signal is subjected to waveform shaping by an equalizer 14, converted into digital “0” and “1” data by an RF binarization circuit 15, input to a demodulation circuit 16, and demodulated. The data demodulated by the demodulation circuit 16 is supplied to the ECC decoding circuit 17, and when there is an error in the data, the data is corrected and the original information is reproduced.

The magneto-optical signal is recorded / reproduced in this manner. The value of the optimum recording laser power required for recording described above is set in advance as follows.

That is, prior to actual data recording,
A method for detecting a recording laser power by a magnetic field modulation recording method according to an embodiment of the present invention is performed. This allows
As described later, the value of the laser power is determined by a recording mark,
It is detected as the magnitude of the phase difference of the reproduced signal. Therefore, the recording laser power at the phase difference at the preset optimum recording laser power (recording laser power optimum phase difference) is detected, and the detected laser power value is set as the optimum recording laser power value. To do.

First, an embodiment of a method for detecting recording laser power by magnetic field modulation recording according to the present invention will be described.

In FIG. 1, the system controller 10
Controls the position of the optical pickup 4 by controlling the thread servo circuit 5 so that an APC area preset on the magneto-optical disk is used as a recording / reproducing area for detecting the recording laser power. I do.

Next, the system controller 10 detects the APC area based on the address signal from the address decoding circuit 9, and outputs a timing signal (APC area signal) indicating the position of the detected APC area. This APC area signal is input to the APC area reference signal generation circuit 17 and is also supplied to the selector 13 so that the selector 1
3 is controlled to select the output signal of the APC area reference signal generation circuit 21 only in the APC area specified by the APC area signal.

The APC area reference signal generation circuit 17
An inspection reference signal (inspection recording mark pattern) having a constant period is output in the PC area. This inspection reference signal is input to the magnet drive circuit 8 through the selector 13, and the external magnetic field generation coil 5 generates a desired recording magnetic field. In this example, a recording magnetic field that changes at a duty of 50% in both directions of + Hw and -Hw as shown in FIG. 2B is generated, similar to that shown in FIG. 5C.

At the same time, the system controller 10
Represents the recording laser power, as shown in FIG.
The laser power control circuit 6 is controlled so that the power is changed stepwise from low power to high power. For example, in the case of the example of FIG. 5, the laser power is sequentially changed from 8 mW to 0.5 mW every unit time.
It is changed to step up. The laser power control circuit 6 controls the output laser power of the semiconductor laser of the optical pickup 4 according to this control.

At this time, in this example, the laser power control circuit 6 irradiates the laser in a pulse form from the semiconductor laser in synchronism with the external magnetic field generated by the external magnetic field generating coil 5 based on the above-mentioned inspection reference signal. The semiconductor laser is driven and controlled in such a manner (see FIG. 5B). In the case of the example of FIG. 5, recording is performed using three recording laser pulses for each of the ± Hw external magnetic fields. Note that, instead of irradiating the laser in a pulse shape, the laser may be DC-irradiated (directly irradiated).

By the above process, the recording mark pattern for inspection (FIG. 5D and FIG.
(See (A)) is written in the APC area of the magneto-optical disk 1. In the inspection recording mark pattern, when the laser power is low, the next recording mark has few overwrite portions overlapping the previous recording mark, but as the laser power increases, the next recording mark becomes the same as the previous recording mark. It can be seen that the overlapping overwrite portion becomes large.

Next, the recording mark pattern for inspection as shown in FIG. 2A recorded in the APC area as described above is reproduced. Then, from the optical pickup 4, FIG.
An MORF signal having a waveform as shown in FIG.

The MORF signal is supplied to the RF binarization circuit 15 and the gate generation circuit 22 via the equalizer 14. The gate generation circuit 22 has a predetermined threshold ± Vth for the amplitude of the RF signal, compares the threshold ± Vth with the amplitude of the MORF signal,
A gate signal GT (see FIG. 2D) for extracting only the MORF signal exceeding the threshold value ± Vth is generated, and the gate signal GT is supplied to the RF binarization circuit 15.

The RF binarization circuit 15 outputs the gate signal G
By T, only the signal whose amplitude is larger than ± threshold value Vth is output from the MORF signal. Thereby, MORF
Unwanted components that are not proper power in the portion where the recording laser power is low in the signal are excluded from the target of proper recording laser power inspection. At this time, the APC area reference signal generation circuit 2
1 is supplied to the RF binarization circuit 15, and the RF binarization circuit 15 outputs the reproduced RF binarization signal PB in the APC area indicated by the APC area signal.
(See FIG. 2E) only.

In FIG. 2, the invalid data portion eliminated by the gate signal GT is also shown for reference. However, as described above, this invalid data portion is actually
No signal is output from the RF binarization circuit 15.

The reproduced RF binarized signal PB in the APC area from the RF binarization circuit 15 is supplied to the phase difference detection circuit 23. Then, the inspection reference signal REF (see FIG. 2F) used for recording is supplied from the APC area reference signal generation circuit 21 to the phase difference detection circuit 23. In the phase difference detection circuit 23, the phase of the inspection reference signal REF is compared with the phase of the reproduced RF binary signal PB of the inspection reference signal. In this example, this phase comparison is performed by an exclusive OR operation (exclusive OR), and by this operation, a detection output EXOR of the phase difference Φ between the two (FIG. 2 (G)
Reference) is obtained.

As described above, when the laser power is low, the recording mark pattern of the inspection reference signal REF is
The overwrite portion where the next recording mark overlaps the previous recording mark is small, and as the laser power increases, the overwriting portion where the next recording mark overlaps the previous recording mark increases. Therefore, the reproduced RF binary signal PB
(FIG. 2E) and an inspection reference signal REF (FIG.
(F)) is large when the laser power is low, and becomes small as the laser power becomes high.
Of the detection output EXOR corresponding to the detection output EXOR, as shown in FIG.

The phase difference detecting circuit 23 supplies the exclusive OR output EXOR to the appropriate power determining circuit 24 through a low-pass filter (not shown). At this time, the phase difference detection output from the phase difference detection circuit 23 changes as shown in FIG. 2H according to the change in the laser power value when the inspection reference signal is recorded. That is, information on a change in the recording laser power value is obtained as information on a change in the phase difference Φ. In other words, the playback R
A change in the recording laser power can be detected as a change in the phase between the F-binarized signal PB and the inspection reference signal REF.

The appropriate power determining circuit 24 determines the value of the recording laser power at the time of the target phase difference Φa held in the target phase difference holding circuit 25 as the value of the optimum recording laser power. The target phase difference Φa is set to a value of a predetermined phase difference (recording power optimum phase difference) within an appropriate power range which is not low power and not high power which destroys recording data of an adjacent track. Stipulated.

In the appropriate power determining circuit 24, the low power reproduced RF binarized signal PB is treated as invalid data by the gate signal GT from the gate generating circuit 22 and is not input. Then, the appropriate power determining circuit 24 can detect the phase difference information according to the power from the appropriate power to the high power, and thus determines the recording laser power value with the effective data that becomes the target phase difference Φa.

For example, the proper power determining circuit 19 is shown in FIG.
In the case of stepping up sequentially for each unit time as in the example of the above, by knowing at what order of the laser power step the target reference phase was recorded when the inspection reference signal waveform was recorded. , MW is the target power. In the example shown in FIG. 2, the value of the laser power at which the optimum phase difference Φa is 10.5 mW in the sixth step.
This 10.5 mW is detected as the value of the optimum recording laser power.

The appropriate power determining circuit 19 sends to the system controller 10 information on the number of steps at which the optimum phase difference is reached as information on the appropriate recording laser power. The system controller 10 supplies information on the appropriate recording power indicating the order of the step to the laser power control circuit 6 as recording power setting information. The laser power control circuit 6 sets the optimum laser recording power based on the information on the appropriate recording power. In the case of this example, since the sixth laser power is optimal and is 10.5 mW, the optimum recording laser power value is set to 10.5 mW, and at the time of recording, the set power is used. Record the data.

As described above, the recording / reproducing apparatus of the example shown in FIG. 1 records the reference signal for inspection using the APC area while changing the laser power, and reproduces it before recording. The optimum recording laser power is detected as described above to control the recording laser power.

In the example described above, the exclusive OR of the binarized reproduction RF signal (MORF signal) of the inspection reference signal and the inspection reference signal which is binarized data is obtained and recorded. Although the information on the phase difference Φ as the information according to the change in the laser power is obtained, the information on the phase difference Φ according to the change in the recording laser power can also be obtained without using the exclusive OR operation.

FIG. 3 is a diagram for explaining an example of a method not using the exclusive OR operation. In this example, the reproduction RF signal of the inspection reference signal is sampled by the inspection reference signal REF to obtain information on the phase difference Φ corresponding to the change in the recording laser power.

FIGS. 3 (A), (B) and (C) show FIG.
(C), (D), and (F), which are a reproduced RF waveform (MORF signal) of a test reference signal, a gate signal, and a test reference signal REF, respectively.

In this example, as shown in FIG. 3D, the reproduced RF waveform of the test reference signal is sampled at the rising edge of the test reference signal REF, so that the waveform shown in FIG. As shown, a phase difference detection signal that changes according to the value of the recording laser power is obtained. Therefore, the optimum recording laser power value can be set by determining the target phase difference Φa in the effective data in the same manner as in the above-described example.

Another example not using the exclusive OR operation is not limited to the above example. For example, a method of forming a sawtooth wave rising at the rising edge of the signal REF in synchronization with the inspection reference signal REF and sampling and holding the sawtooth wave at the rising edge of the reproduced RF binary signal PB may be used. it can. In this case, if the sample-and-hold signal is passed through a low-pass filter, a phase difference detection signal that changes according to the value of the recording laser power can be obtained.

By using the above method,
By recording the recording mark of the reference signal for inspection in the APC area,
By reproducing it and detecting the phase difference between the reproduced signal and the inspection reference signal, the recording laser power in the magnetic field modulation recording method can be detected.

The target optimum phase difference Φa is obtained, for example, as follows. First, a standard magneto-optical disk is prepared as a recording medium. A recording device having an average characteristic (a concept including a recording system of a recording / reproducing device).
Hereinafter, the same method is used to detect the recording laser power, and the information on the change in the phase difference according to the change in the recording laser power is detected. Then, it is considered that the optimum power is within the range of the appropriate power, excluding the low-power area which is invalidated by the gate signal GT and becomes ineffective, and the high-power area which destroys the recording data of the adjacent track. The value of the recording laser power to be used is selected, and the phase difference corresponding to the value of the optimum recording laser power is set as the optimum phase difference Φa. Then, the optimum phase difference Φa is set in the target phase difference holding circuit 25.

The optimum phase difference Φa set as described above
Is a standard one, so the optimum recording laser power set prior to actual data recording differs as described above in each recording device due to variations in the characteristics of the laser drive system for each recording device. It may be set as something.

When the optimum recording laser power is kept constant irrespective of the variation in the characteristics of the laser drive system in all the recording devices, the information of the optimum phase difference Φ stored in the target phase difference holding circuit 25 is recorded. What is necessary is just to make it different for every apparatus.

For this purpose, the following is performed. That is, for example, the inspection reference signal REF is recorded in the APC area of the magneto-optical disk with the optimum recording laser power obtained by the standard recording apparatus as described above, and is reproduced. Then, the phase difference between the reproduced signal and the inspection reference signal REF is obtained by the above-described method, and the information of the phase difference is
It is stored in the target phase difference holding circuit 25.

Using the optimum phase difference thus set as the target phase difference, the above-described setting of the recording laser power is
In each recording apparatus, if executed prior to actual recording, the set value of the recording laser power is set to a predetermined optimum value even if the laser drive system has variations in characteristics. .

As described above, according to the above-described embodiment, even in the magnetic field modulation recording method, the reproduction RF signal of the power setting area (not limited to the APC area) on the recording medium corresponds to the recording laser power. Information to be detected can be detected. Therefore, a recording mark can be recorded with the optimum recording laser power.

In this case, the reliability is high because the phase difference information is detected not from the power monitor of the laser emission light but from the actually recorded mark according to the recording laser power value.

Then, the recording laser power can be set without performing trial writing on both adjacent tracks, so that the recording laser power can be set quickly. Further, since the recording laser power can be set without performing test writing on the tracks on both sides, there is also an effect that the APC area on the magneto-optical disk can be reduced.

[Other Embodiments] In the above embodiment, the recording apparatus or the recording / reproducing apparatus uses the APC area to change the recording laser power and change the inspection reference signal before the actual data recording. And the optimum recording laser power is set based on the information of the phase difference between the reproduced signal and the reference signal for inspection. Of course, it can be used when setting the optimum recording laser power of the reproducing apparatus. In this case, the recording device or the recording / reproducing device may not include a means for detecting a change in the recording laser power as a change in the phase difference Φ.

Although the recording and reproduction of the inspection reference signal are performed using the APC area, the recording and reproduction of the inspection reference signal are performed prior to recording. The present invention is not limited to this, and any area may be used as long as the address is known in advance.

The recording method to which the present invention is applied is not limited to the magnetic field modulation recording method.
For example, the present invention can be applied to a phase change recording method. Data recording is not limited to land recording, but may be groove recording.

[0078]

As described above, according to the present invention, in a magnetic field modulation recording system, information corresponding to a recording laser power is converted into a reference signal for inspection and a reproduction signal from a recording medium on which the signal is recorded. Can be detected as information on the phase difference between the two.

That is, according to the present invention, a phase difference signal according to the recording laser power is detected not from the power monitor of the laser emission light but from the actually recorded recording mark, so that the reliability is high. Therefore, the optimum recording laser power can be easily set based on the phase difference, and the mark can be recorded with the optimum recording laser power.

According to the present invention, when setting the appropriate recording laser power for the magnetic field modulation recording method, it is not necessary to test-write an inspection reference signal on both adjacent tracks to check whether data is destroyed. Therefore, the recording laser power can be quickly set.

[Brief description of the drawings]

FIG. 1 is an overall block diagram of an embodiment of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram for explaining an embodiment of a recording laser power detection method according to the present invention.

FIG. 3 is a diagram for explaining another embodiment of the recording laser power detection method according to the present invention.

FIG. 4 is a diagram for explaining a reproduced RF waveform according to a change in recording laser power in the case of a light modulation recording method.

FIG. 5 is a diagram for explaining a reproduction RF waveform according to a change in recording laser power in the case of a magnetic field modulation recording method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magneto-optical disk, 4 ... Optical pickup, 6 ... Laser power control circuit, 7 ... External magnetic field generating coil (magnetic head), 8 ... Magnet drive circuit, 9 ... Address decoding circuit, 10 ... System controller, 15 ...
RF binarization circuit, 21 APC area reference signal generation circuit, 22 gate generation circuit, 23 phase difference detection circuit, 2
4: Appropriate power determination circuit, 25: Target phase difference holding circuit

Claims (25)

[Claims] 1. A laser beam is irradiated onto a recording medium to form recording marks that can take two states alternately in the two states, and form a next recording mark in a state that partially overlaps a preceding recording mark. A method for detecting a recording laser power used in a recording method for recording on a recording medium in such a manner that a reference signal for inspection of a predetermined pattern is recorded on the recording medium while changing the recording laser power. Obtaining a recorded reproduction signal of the inspection reference signal from the recording medium; and combining the inspection reference signal and the reproduction signal of the inspection reference signal at each value of the recording laser power. A method for detecting recording laser power, comprising detecting information on a change in recording laser power as information on a change in phase difference. 2. The recording laser power detection method according to claim 1, wherein a phase difference between an edge phase of the recorded reproduction signal of the inspection reference signal and an edge phase of the inspection reference signal. Wherein the information on the change in the recording laser power is detected as the information on the change in the recording laser power. 3. The method for detecting recording laser power according to claim 1, wherein the reproduction signal of the recorded inspection reference signal is sampled at a phase of an edge of the inspection reference signal, thereby obtaining the position. A method for detecting recording laser power, wherein information on a change in phase difference is obtained. 4. The recording laser power detection method according to claim 1, wherein an optimum recording laser power phase difference is determined in advance for said phase difference, and said recording laser power corresponding to said optimum phase difference is determined. The recording laser power is detected as an optimum recording laser power value. 5. The recording laser power detection method according to claim 4, wherein when detecting the optimum recording laser power value, the amplitude of a reproduction signal of the inspection reference signal is equal to or greater than a predetermined value. A method for detecting recording laser power, wherein a reproduction signal is a detection target. 6. A method according to claim 1, wherein said recording method is a magnetic field modulation recording method. 7. A recording mark that can take two states is formed alternately while irradiating a recording medium with a laser, and a next recording mark is formed while partially overlapping the previous recording mark. An apparatus for detecting the power of a recording laser used for a recording method of recording on a recording medium by forming the recording medium, wherein a reference signal for inspection of a predetermined pattern is changed while changing the recording laser power. Recording means for recording on the recording medium; reproducing means for obtaining a reproduction signal of the inspection reference signal recorded by the recording means from the recording medium; when the inspection reference signal and the recording laser power have respective values. Recording means for detecting information on a change in the recording laser power as information on a change in a phase difference between the inspection reference signal and a reproduction signal. Power of the detection device. 8. The detecting means detects information on a change in the recording laser power as information on a change in a phase difference between the phase of the edge of the reproduction signal and the phase of the edge of the reference signal for inspection. The recording laser power detection device according to claim 7, wherein: 9. The detection means obtains information on a change in the phase difference by sampling a reproduced signal of the inspection reference signal at a phase of an edge of the inspection reference signal. Item 8. A recording laser power detection device according to item 7. 10. The recording laser power detecting apparatus according to claim 7, wherein an optimum recording laser power phase difference is determined in advance for said phase difference, and based on a detection result of said detection means, An apparatus for detecting a recording laser power, comprising an optimum recording laser power value setting means for setting a value of the recording laser power according to an optimum phase difference as an optimum recording laser power value. 11. The recording laser power detecting device according to claim 10, wherein the optimum recording laser power value detecting means is configured to detect the reproduction signal whose amplitude of the reproduction signal of the inspection reference signal is equal to or larger than a predetermined value. A means for setting the optimum recording laser power value for a detection result. 12. A recording laser power detecting apparatus according to claim 7, wherein said recording system is a magnetic field modulation recording system. 13. While irradiating a laser on a recording medium,
In a recording apparatus which performs recording on a recording medium by forming a recording mark capable of taking a state alternately in the two states and forming a next recording mark in a state partially overlapping a previous recording mark, A laser light source that emits the laser, a laser power control unit that changes and controls a laser power output from the laser light source, receives reflected light of the laser from the recording medium, and outputs a read output of the recording mark. Reading means for obtaining; a recording mark recording means for recording a reference signal for inspection of a predetermined pattern on the recording medium while changing the laser power by the laser power control means; and a recording mark recording for inspection. Means for reading the reference signal for inspection recorded by the reading means, and reading the reference signal for inspection with the laser power. Detecting means for detecting information on a change in the recording laser power as information on a change in a phase difference between the reference signal for inspection and a reproduced signal at each of the values of the above, and information detected by the detecting means A recording apparatus for controlling a laser power at the time of recording according to the following. 14. The detecting means detects information on a change in the recording laser power as information on a change in a phase difference between the phase of the edge of the reproduction signal and the phase of the edge of the reference signal for inspection. 2. The method according to claim 1, wherein
4. The recording device according to 3. 15. The apparatus according to claim 13, wherein said detecting means obtains information on a change in the phase difference by sampling the reproduced signal at a phase of an edge of the inspection reference signal. Recording device. 16. The recording apparatus according to claim 13, wherein an optimum recording laser power value corresponding to a predetermined recording laser power optimum phase difference is determined based on a detection output of said detection means. A recording apparatus comprising an optimum recording laser power value setting means for setting power control means. 17. The recording apparatus according to claim 16, wherein said optimum recording laser power value setting means detects a detection result of said reproduction signal whose amplitude of said reproduction signal of said inspection reference signal is equal to or greater than a predetermined value. Recording means for setting the optimum recording laser power value for the recording apparatus. 18. The recording apparatus according to claim 13, wherein the recording system is a magnetic field modulation recording system. 19. The recording apparatus according to claim 16, wherein a reference signal for inspection of a predetermined pattern is controlled by the laser power control means of the laser light source.
Means for recording on the recording medium in a state of a predetermined optimum recording laser power value, and setting a phase difference between a reproduction signal thereof and the inspection reference signal as the recording laser power optimum phase difference. Characteristic recording device. 20. While irradiating a laser on a recording medium,
In a recording apparatus which performs recording on a recording medium by forming a recording mark capable of taking a state alternately in the two states and forming a next recording mark in a state partially overlapping a previous recording mark, A laser light source that emits the laser, a laser power control unit that changes and controls a laser power output from the laser light source, receives reflected light of the laser from the recording medium, and outputs a read output of the recording mark. Reading means to obtain, a reference signal for inspection of a predetermined pattern, by the laser power control means of the laser light source,
Inspection reference signal recording means for recording on the recording medium in the state of the optimum recording laser power value, The inspection reference signal recorded by the inspection reference signal recording means is read by the reading means, the reproduction signal thereof Recording power adjustment means for adjusting a value of the optimum recording laser power set by the laser power control means so that a phase difference from the inspection reference signal becomes a predetermined optimum phase difference. A recording device, characterized in that: 21. A recording / reproducing apparatus comprising the recording apparatus according to claim 13 in a recording system. 22. A laser beam is irradiated on a recording medium to form recording marks which can take two states alternately in the two states, and form the next recording mark in a state partially overlapping the previous recording mark. A method for controlling a recording laser power used in a recording method for recording on a recording medium in such a manner that a reference signal for inspection of a predetermined pattern is recorded on the recording medium while changing the recording laser power. Obtaining a recorded reproduction signal of the inspection reference signal from the recording medium; and combining the inspection reference signal and the reproduction signal of the inspection reference signal at each value of the recording laser power. The correspondence between the information on the change in the phase difference and the information on the change in the recording laser power is detected, and the value of the recording laser power at the predetermined recording laser power optimum phase difference is recorded. A recording laser power control method characterized by setting an optimum recording laser power value at the time of recording. 23. The recording laser power control method according to claim 22, wherein said optimum phase difference is determined for each recording device in consideration of its variation. 24. A reference signal for inspection of a predetermined pattern is recorded on the recording medium in the state of the optimum recording laser power value, and a reproduced signal of the reference signal for inspection and the reference signal for inspection are recorded. 24. The recording laser power control method according to claim 22, wherein the value of the optimum recording laser power is calibrated so that a phase difference between the optimum recording laser power and the optimum recording laser power becomes the optimum phase difference. 25. A method according to claim 22, wherein said recording system is a magnetic field modulation recording system.