JP2001229590A - Magneto-optical recorder, magneto-optical reproducing device and their methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-optical recorder recording prescribed information in the state incapable of being reproduced by recording/reproducing processing of a usual and regular magneto-optical recording medium together with contents signals on the magneto-optical recording medium. SOLUTION: ID information showing the serial number of the magneto-optical disk 1 is recorded on the magneto-optical disk 1 together with the contents signals S30. In the relevant recording, a magnetic field applied to a laser irradiation position (signal recording position) on the magneto-optical disk 1 is modulated, and a recording mark according to the contents signals S30 is formed on the magneto-optical disk 1, and at this time, a phase of a laser drive signal is modulated, and the ID information is recorded. Further, the reproduction of the ID information is detected in an ID information detecting circuit 22 based on a VCO control voltage of a PLL circuit.

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 apparatus, a magneto-optical reproducing apparatus, and a method for recording information using a laser beam.

[0002]

2. Description of the Related Art In a recording / reproducing apparatus for a magneto-optical recording medium, recording is performed from a magnetic head in a state where a signal recording position of the magneto-optical recording medium is irradiated with a laser beam to raise the temperature of the position to the Curie temperature. A signal is recorded by applying a magnetic field according to the information and magnetizing the position according to the recording information.
In addition, the recording / reproducing apparatus irradiates a laser beam to a signal reproducing position on a magneto-optical recording medium during reproduction, and reproduces a signal based on the polarization state of the reflected light. In a conventional recording / reproducing apparatus for a magneto-optical recording medium, a laser beam emitted from a laser is controlled based on a laser drive pulse signal. At this time, the laser drive pulse signal is not modulated and has a constant pulse height (amplitude), pulse width, and phase.

[0003]

In recent years, in order to prevent illegal copying of a content signal such as video and audio, particularly a content signal distributed via a network, to a recording medium, the normal recording and reproduction as described above is performed. There is a demand that information for preventing unauthorized duplication be recorded on a magneto-optical recording medium together with a content signal so that reproduction and recording cannot be performed in the processing. However, the above-mentioned conventional recording / reproducing apparatus cannot meet such a demand.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magneto-optical recording apparatus capable of recording predetermined information on a magneto-optical recording medium together with a content signal in a state where the information cannot be reproduced by a conventional ordinary magneto-optical recording and reproducing process, and a method thereof. It is to be. Another object of the present invention is to provide a magneto-optical reproducing apparatus capable of reproducing predetermined information recorded in this manner independently of reproduction of a normal content signal, and a method thereof.

[0005]

In order to solve the above-mentioned problems of the prior art and to achieve the above-mentioned object, a magneto-optical recording apparatus according to a first aspect of the present invention employs a light beam based on a drive signal. A light source for irradiating the magneto-optical recording medium with light, a driving signal generating circuit for generating the driving signal, and a light beam on the magneto-optical recording medium for applying a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium And a drive signal modulation circuit that modulates the drive signal in accordance with the second information recorded on the magneto-optical recording medium.

The operation of the magneto-optical recording apparatus according to the first aspect of the present invention is as follows. A light beam from a light source is applied to a recording target position on the magneto-optical recording medium, and the temperature at that position is raised to a Curie temperature or higher. In that state, the first
Is supplied from the magnetic head to the recording target position, the recording target position has a polarity corresponding to the direction of the magnetic field. Then, when the recording target position is no longer irradiated with the light beam, the temperature of the recording target position becomes lower than the Curie temperature, and the polarity is maintained. In the magneto-optical recording device, the drive signal of the light source is modulated according to the second information. Therefore, the influence of this modulation appears in the state of the polarity held in the magneto-optical recording medium. In the magneto-optical reproducing apparatus of the present invention described later, the second information recorded together with the first information on the magneto-optical recording medium is detected by detecting the polarity state of the recording surface of the magneto-optical recording medium. To detect. The following magneto-optical recording device of the present invention specifies a method of modulating the drive signal according to the second information.

A magneto-optical recording device according to a second aspect of the present invention comprises:
A light source for irradiating the magneto-optical recording medium with a light beam based on the driving pulse signal; a driving signal generating circuit for generating the driving pulse signal; and a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium. A magnetic head for applying the light beam to the irradiation position on the magneto-optical recording medium; and a driving signal modulation circuit for modulating the phase of the driving pulse signal in accordance with the second information to be recorded on the magneto-optical recording medium. .

A magneto-optical recording device according to a second aspect of the present invention comprises:
Preferably, the second information is information used to control at least one of recording and reproduction of the first information.

A magneto-optical recording apparatus according to a second aspect of the present invention comprises:
Preferably, the second information includes a first logical value and a second logical value, and the driving signal modulating circuit includes the second logical value.
The phase of the pulse of the drive pulse signal is shifted in a first direction with respect to the phase of the master clock signal in accordance with the first logical value of the information, and in accordance with the second logical value of the second information. Thus, the phase of the pulse of the drive pulse signal is shifted in the second direction with respect to the phase of the master clock signal.

A magneto-optical recording apparatus according to a third aspect of the present invention comprises:
A light source for irradiating the magneto-optical recording medium with a light beam based on the driving pulse signal; a driving signal generating circuit for generating the driving pulse signal; and a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium. A magnetic head for applying the light beam irradiation position on the magneto-optical recording medium, and a drive signal modulation circuit for modulating a pulse height of the drive pulse signal in accordance with second information recorded on the magneto-optical recording medium And
Magneto-optical recording device.

A magneto-optical recording device according to a fourth aspect of the present invention comprises:
A light source for irradiating the magneto-optical recording medium with a light beam based on the driving pulse signal; a driving signal generating circuit for generating the driving pulse signal; and a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium. A magnetic head for applying the light beam irradiation position on the magneto-optical recording medium, a drive signal modulation circuit for modulating a pulse width of the drive pulse signal in accordance with second information to be recorded on the magneto-optical recording medium; Having.

According to a fifth aspect of the present invention, there is provided a magneto-optical recording apparatus comprising: a light source for irradiating a light beam to a magneto-optical recording medium based on a driving signal; a driving signal generating circuit for generating the driving signal; A magnetic head for applying a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium to the irradiation position of the light beam on the magneto-optical recording medium; and the drive signal according to the second information to be recorded on the magneto-optical recording medium. And a drive signal modulation circuit for modulating the amplitude of the signal.

A magneto-optical recording device according to a sixth aspect of the present invention comprises:
A light source for irradiating a light beam to the magneto-optical recording medium based on the driving signal; a driving signal generating circuit for generating the driving signal; and a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium. A magnetic head applied to the light beam irradiation position on the recording medium; and a second head used to control at least one of recording and reproduction of the first information.
And a drive signal modulation circuit that generates a third information by performing a logical operation on the information of the first information and the first information, and modulates the drive signal in accordance with the third information.

A magneto-optical recording device according to a seventh aspect of the present invention comprises:
A light source for irradiating the magneto-optical recording medium with a light beam, a magnetic head for supplying a magnetic field according to a drive signal to an irradiation position of the light beam, and a magnetic head for supplying a magnetic field in a direction corresponding to the first information. A driving signal generating circuit for generating a driving signal, and a driving signal modulating circuit for modulating the driving signal so as to cause intersymbol interference according to the second information.

Further, a magneto-optical reproducing apparatus according to a first aspect of the present invention comprises a light source for irradiating a light beam to a magneto-optical recording medium, and a light receiving circuit for receiving reflected light of the light beam from the magneto-optical recording medium. A signal generation circuit for generating a magneto-optical reproduction signal based on a light-receiving result of the light-receiving circuit, a PLL circuit for performing phase synchronization processing on the magneto-optical reproduction signal, and a voltage-controlled oscillation circuit of the PLL circuit. An information detection circuit for detecting information in the magneto-optical reproduction signal based on the drive voltage signal.

The operation of the magneto-optical reproducing apparatus according to the first aspect of the present invention is as follows. A light beam from a light source is applied to the magneto-optical recording medium, and the reflected light is received by a light receiving circuit. Next, in a signal generation circuit, a magneto-optical reproduction signal is generated based on a light reception result of the light reception circuit. The generated magneto-optical reproduction signal is subjected to a phase synchronization process in a PLL circuit. At this time, the drive voltage signal of the voltage controlled oscillation circuit of the PLL circuit is output to the information detection circuit. The information detection circuit detects information in the magneto-optical reproduction signal based on the drive voltage signal.

A magneto-optical reproducing apparatus according to a first aspect of the present invention comprises:
Preferably, the apparatus further comprises a reproduction circuit for generating a reproduction signal based on the amplitude of the magneto-optical reproduction signal.

A magneto-optical reproducing apparatus according to a first aspect of the present invention comprises:
Preferably, the phase change of the magneto-optical reproduction signal is
The LL circuit has a time constant that can be followed by the phase processing.

A magneto-optical reproducing apparatus according to a first aspect of the present invention comprises:
Preferably, the information is information used for controlling at least one of recording and reproduction of the first reproduction signal.

A magneto-optical reproducing apparatus according to a second aspect of the present invention comprises:
A light source for irradiating the magneto-optical recording medium with a light beam; a light receiving circuit for receiving the reflected light of the light beam from the magneto-optical recording medium; and generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit. A signal generation circuit, a PLL circuit that performs a phase synchronization process on the magneto-optical reproduction signal, and a time difference between the magneto-optical reproduction signal and a PLL clock signal output from a voltage-controlled oscillation circuit of the PLL circuit. An information detection circuit for detecting information in the magneto-optical reproduction signal.

A magneto-optical reproducing apparatus according to a second aspect of the present invention comprises:
Preferably, the information detection circuit is configured to output the magneto-optical reproduction signal and a P-level signal output from a voltage-controlled oscillation circuit of the PLL circuit.
A time difference detection circuit for detecting a time difference from the LL clock signal to generate a time difference signal; a comparison circuit for comparing the amplitude of the time difference detection signal with a predetermined value to generate a comparison result signal; And an encoding circuit for reproducing the information in the magneto-optical reproduction signal.

A magneto-optical reproducing apparatus according to a second aspect of the present invention comprises:
The phase change of the magneto-optical reproduction signal has a time constant that the phase processing of the PLL circuit cannot follow.

A magneto-optical reproducing apparatus according to a third aspect of the present invention comprises:
A light source for irradiating the magneto-optical recording medium with a light beam; a light receiving circuit for receiving the reflected light of the light beam from the magneto-optical recording medium; and generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit. A signal generation circuit; and an information detection circuit that calculates a center value of the amplitude of the magneto-optical reproduction signal and detects information in the magneto-optical reproduction signal based on the calculated center value.

A magneto-optical reproducing apparatus according to a fourth aspect of the present invention comprises:
A light source for irradiating the magneto-optical recording medium with a light beam; a light receiving circuit for receiving the reflected light of the light beam from the magneto-optical recording medium; and generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit. A signal generation circuit; and an information detection circuit for detecting information in the magneto-optical reproduction signal based on a state of intersymbol interference in the magneto-optical reproduction signal.

The magneto-optical recording method according to the first aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam based on the drive signal, and applying a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium to an irradiation position of the light beam on the magneto-optical recording medium; A magneto-optical recording method for modulating the drive signal in accordance with second information recorded on the magneto-optical recording medium.

A magneto-optical recording method according to a second aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam based on the drive pulse signal, and applying a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium to the irradiation position of the light beam on the magneto-optical recording medium; And modulating the phase of the drive pulse signal according to the second information recorded on the magneto-optical recording medium.

A magneto-optical recording method according to a third aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam based on the drive pulse signal, and applying a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium to the irradiation position of the light beam on the magneto-optical recording medium; And modulating the pulse height of the drive pulse signal according to the second information to be recorded on the magneto-optical recording medium.

A magneto-optical recording method according to a fourth aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam based on the drive pulse signal, and applying a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium to the irradiation position of the light beam on the magneto-optical recording medium; And modulating the pulse width of the drive pulse signal according to the second information recorded on the magneto-optical recording medium.

A magneto-optical recording method according to a fifth aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam based on the drive signal, and applying a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium to an irradiation position of the light beam on the magneto-optical recording medium; The amplitude of the drive signal is modulated according to the second information recorded on the magneto-optical recording medium.

A magneto-optical recording method according to a sixth aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam based on the drive signal, and applying a magnetic field corresponding to the first information to be recorded on the magneto-optical recording medium to an irradiation position of the light beam on the magneto-optical recording medium; A third information is generated by performing a logical operation on the second information used for controlling at least one of recording and reproduction of the first information and the first information, and the third information is generated. The drive signal is modulated accordingly.

A magneto-optical recording method according to a seventh aspect of the present invention comprises:
A light beam is applied to the magneto-optical recording medium, a magnetic field corresponding to the drive signal is supplied to the irradiation position of the light beam, and a drive signal is generated so that the magnetic head supplies a magnetic field in a direction corresponding to the first information. Then, the drive signal is modulated so as to cause intersymbol interference according to the second information.

The magneto-optical reproducing method according to the first aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam, receiving the reflected light of the light beam from the magneto-optical recording medium, generating a magneto-optical reproduction signal based on the light reception result, Performs a phase synchronization process using a PLL circuit,
The information in the magneto-optical reproduction signal is detected based on a drive voltage signal of a voltage controlled oscillation circuit of the PLL circuit.

The magneto-optical reproducing method according to the second aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam, receiving reflected light of the light beam from the magneto-optical recording medium, generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit, The signal is subjected to a phase synchronization process using a PLL circuit, and based on a time difference between the magneto-optical reproduction signal and a PLL clock signal output from a voltage-controlled oscillation circuit of the PLL circuit, the signal in the magneto-optical reproduction signal is Detect information.

A magneto-optical reproducing method according to a third aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam, receiving reflected light of the light beam from the magneto-optical recording medium, generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit, A center value of the amplitude of the signal is calculated, and information in the magneto-optical reproduction signal is detected based on the calculated center value.

A magneto-optical reproducing method according to a fourth aspect of the present invention comprises:
Irradiating the magneto-optical recording medium with a light beam, receiving reflected light of the light beam from the magneto-optical recording medium, generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit, Information in the magneto-optical reproduction signal is detected based on the state of intersymbol interference in the signal.

[0036]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First Embodiment FIG. 1 is a block diagram of a recording / reproducing apparatus 40 of the present embodiment. As shown in FIG. 1, the recording / reproducing device 40 includes, for example,
Motor 2, laser 8, photodetectors 11, 13, current-voltage conversion circuit 14, signal generation circuit 15, phase compensation circuit 16,
Axis drive circuit 17, sector detection circuit 19, timing generation circuit 20, content reproduction circuit 21, ID information detection circuit 22, magnetic head drive signal generation circuit 23, magnetic head drive circuit 24, laser drive circuit 25, laser drive signal generation circuit 26, magnetic head 27, laser drive signal modulation circuit 2
8. PLL (Phase Locked Loop) circuit 29, optical system 30
And a control circuit 31. Here, the laser 8 corresponds to the light source of the invention, the laser drive signal generation circuit 26 corresponds to the drive signal generation circuit of the invention, the magnetic head 27 corresponds to the magnetic head of the invention, and the laser drive signal modulation circuit. 28
Corresponds to the drive signal modulation circuit of the present invention. The photodetectors 11 and 13 correspond to the light receiving circuit of the present invention, the signal generating circuit 15 corresponds to the signal generating circuit of the present invention, the PLL circuit 29 corresponds to the PLL circuit of the present invention, and the ID information detecting circuit. Reference numeral 22 corresponds to the information detection circuit of the present invention.

The recording / reproducing device 40 records the ID information indicating the serial number of the magneto-optical disk 1 on the magneto-optical disk 1 together with the content signal S30 received (downloaded) via satellite communication or the Internet, for example. In the recording, the recording / reproducing device 40 modulates the magnetic field applied to the laser irradiation position (signal recording position) on the magneto-optical disk 1 to form a recording mark on the magneto-optical disk 1 in accordance with the content signal S30. In this case, ID information is recorded by modulating the phase of the laser drive signal. As the ID information, for example, a serial number of the magneto-optical disk 1 is used.

The recording / reproducing apparatus 40 performs a process of reproducing the ID information when reproducing the content signal from the magneto-optical disk 1. Based on the result, the recording / reproduction of the content signal is illegally performed (duplication, copying) and illegal duplication. A process is performed to prohibit the reproduction of the content signal. In the reproduction, the recording / reproducing device 40 irradiates the magneto-optical disk 1 with a laser beam, detects a content signal from a magneto-optical reproduction signal corresponding to the polarization state of the reflected light, and separately detects the content signal. PLL circuit VCO (Voltage Con
The invention is characterized in that ID information is detected from a controlled voltage.

Hereinafter, each component shown in FIG. 1 will be described.
The control circuit 31 is a controller that controls each circuit in the recording / reproducing device 40, and is constituted by, for example, a microcomputer.

The magnetic head drive circuit 24 drives the magnetic head 27 by supplying an excitation current corresponding to the magnetic head drive signal S23 from the magnetic head drive signal generation circuit 23 to the magnetic head 27. The magnetic head 27 is excited by an exciting current from the magnetic head drive circuit 26 to generate lines of magnetic force, and the content signal S30 to be recorded on the magneto-optical recording medium 1
Is applied to the laser irradiation position (signal recording position). As a result, the signal recording position on the magneto-optical disk 1 is magnetized to the N pole and the S pole according to the content signal S30.

The motor 2 is constituted by, for example, a spindle motor, and rotates the magneto-optical recording medium 1 at a predetermined rotation speed. The magneto-optical recording medium 1 records information by a magnetic field modulation method using a laser beam from a laser 8 and a magnetic field applied from a magnetic head 27. In the present embodiment, a case where a magneto-optical disk is used as the magneto-optical recording medium 1 will be exemplified.

The laser 8 is composed of, for example, a semiconductor laser, and is driven by a laser drive circuit 25. The laser 8 is an example of a light source and a light emitting element that emit coherent light, and outputs a linearly polarized laser beam. The laser beam output from the laser 8 is supplied to an optical system 25, and is condensed by the optical system 25 to irradiate a signal recording position on the magneto-optical disk 1. The signal recording position on the magneto-optical recording medium 1 irradiated with the laser beam is raised to the Curie temperature, and when a magnetic field is applied by the magnetic head 27 in that state, the magnetic field has polarity in the direction of the magnetic field. When the laser beam is not irradiated and the temperature of the position falls below the Curie temperature, the polarity of the position is maintained.

The optical system 25 has a collimator lens 7, beam splitters 5, 9, an objective lens 3, and condenser lenses (cylindrical lenses) 10, 12.

The collimator lens 7 converts the laser beam from the laser 8 into parallel light and supplies it to the beam splitter 5. The beam splitter 5 passes most of the incident laser beam from the collimator lens 7 and supplies it to the objective lens 3. The objective lens 3 converges the laser beam from the beam splitter 5 and supplies the laser beam to the signal recording surface of the magneto-optical disk 1.

At the time of reproduction, the laser beam reflected on the signal recording surface (recording film) of the magneto-optical disk 1 is supplied to the beam splitter 5 via the objective lens 3. The beam splitter 5 reflects the laser beam from the objective lens 3 and supplies the laser beam to a polarization beam splitter (PBS) 9. The polarization beam splitter 9 separates the reflected laser beam from the beam splitter 5 and supplies the separated laser beam to the condenser lenses 10 and 12.
The plane of polarization of the reflected laser beam slightly rotates in the positive or negative direction with respect to the incident laser beam in accordance with the polarities N and S of the magnetization of the magneto-optical disk 1. Therefore,
When the reflected laser beam passes through the polarizing beam splitter 9, the amount of distribution to the photodetectors 10 and 13 differs depending on the polarities N and S. Therefore, a magneto-optical reproduction signal (MO signal) indicating the difference between the distribution amounts is generated. To detect recorded information.

The condenser lens 12 converges the laser beam that has passed through the polarization beam splitter 9 and supplies the laser beam to the photodetector 13. As shown in FIG.
It has divided light receiving areas A, B, C, and D, and photoelectrically converts the laser beam from the condenser lens 12 in each light receiving area to generate currents IA ₁₃ , IB ₁₃ , IC ₁₃ , and ID ₁₃ respectively. These are output to the current-voltage conversion circuit 14.

The condenser lens 10 converges the laser beam reflected by the polarization beam splitter 9 and supplies the laser beam to the photodetector 11. As shown in FIG. 2B, the photodetector 11
It has divided light receiving regions A, B, C, and D, and photoelectrically converts the laser beam from the condenser lens 10 in each light receiving region to generate currents IA ₁₁ , IB ₁₁ , IC ₁₁ , and ID ₁₁ respectively. These are output to the current-voltage conversion circuit 14.

The current-to-voltage conversion circuit 14 includes the photodetector 11,
Currents IA ₁₁ , IB ₁₁ , IC ₁₁ , ID ₁₁ , I
Signals A ₁₁ , B ₁₁ , C ₁₁ , D ₁₁ , A ₁₁ having voltage level amplitudes corresponding to the current values of A ₁₃ , IB ₁₃ , IC ₁₃ , ID _13
13 , B ₁₃ , C ₁₃ , and D ₁₃ are generated and output to the signal generation circuit 15.

The signal generation circuit 15 includes the current / voltage conversion circuit 1
Using the signals A ₁₁ , to D ₁₁ , and A _{13 to} D ₁₃ from
A reproduction signal (RF signal) RF, a focus error signal FE, a tracking error signal TE, and a magneto-optical reproduction signal MO are generated based on the following equations (1) and (2).

[0051]

RF = (A ₁₁ + B ₁₁ + C ₁₁ + D ₁₁ ) + (A ₁₃ + B ₁₃ + C ₁₃ + D ₁₃ )

[0052]

FE = (A ₁₁ + C ₁₁ ) − (B ₁₁ + D ₁₁ ) + (A ₁₃ + C ₁₃ ) − (B ₁₃ + D ₁₃ )

[0053]

TE = (A ₁₁ + B ₁₁ ) − (C ₁₁ + D ₁₁ ) + (A ₁₃ + B ₁₃ ) − (C ₁₃ + D ₁₃ )

[0054]

MO = (A ₁₁ + B ₁₁ + C ₁₁ + D ₁₁ ) − (A ₁₃ + B ₁₃ + C ₁₃ + D ₁₃ )

The reproduction signal RF is supplied to the sector detection circuit 19. The focus error signal FE and the tracking error signal TE are supplied to the phase compensation circuit 16. The magneto-optical reproduction signal MO is, for example, as shown in FIGS.
The content reproduction circuit 21 has the waveform shown in FIG.
And a PLL circuit 29.

The phase compensating circuit 16 generates a compensation signal obtained by compensating (phase compensation and / or frequency compensation) the focus error signal FE and the tracking error signal TE.
It is supplied to the shaft drive circuit 17.

The two-axis drive circuit 17 amplifies the compensation signal of the focus error signal FE and supplies it to a focusing actuator (not shown) of the objective lens 3. This focusing actuator provides a focus error signal FE
The objective lens 3 is moved in a focus direction orthogonal to the signal recording surface of the magneto-optical disk 1 based on the compensation signal of the above, and the focus servo is realized by holding the magneto-optical disk 1 and the objective lens 3 at a predetermined distance. I do.

The biaxial drive circuit 17 amplifies the compensation signal of the tracking error signal TE and supplies it to a tracking actuator (not shown) of the objective lens 3. This tracking actuator moves the objective lens 3 in the radial direction or the tracking direction of the magneto-optical disk 1 based on the compensation signal of the tracking error signal TE, and the center of the focus of the laser beam (particularly the main beam) is the center of the track. Or move it so that it is located near the center,
Implement tracking servo.

The PLL circuit 29 outputs the magneto-optical reproduction signal M shown in FIGS. 3F and 4F from the signal generation circuit 15.
PLL clock signal CLK to the phase of VFO included in O
Performs processing to pull in the phase of the _PLL . The PLL clock signal CLK _PLL has waveforms shown in FIGS. 3 (H) and 4 (H). At this time, when the time constant of the change in the phase of the magneto-optical reproduction signal MO is small, the PLL circuit 29 increases the drive voltage of the VCO (hereinafter, also referred to as the VCO drive voltage) following the change. That is, the phase change of the magneto-optical reproduction signal MO appears in the VCO drive voltage.

The PLL circuit 29 outputs a VCO drive voltage signal S29 indicating the level of the VCO drive voltage to the ID information detection circuit 22. Here, when ID information is not recorded on the magneto-optical disk 1 by phase modulation as described later, the time difference Δ (MO-CLK _PLL ) between the PLL clock signal CLK _PLL and the magneto-optical reproduction signal MO is FIG.
As shown in (I), the voltage becomes substantially zero, and as shown in FIG. 3 (J), the level of the VCO drive voltage signal S29 is also maintained at substantially zero. On the other hand, when ID information is recorded on the magneto-optical disk 1 by phase modulation as described later, a process of pulling the PLL clock signal CLK _PLL into the phase of the magneto-optical reproduction signal MO is performed. Voltage signal S
The level of 29 changes as shown in FIG. FIG. 4 (J) shows the waveform of the VCO drive voltage signal S29 in the process of changing the ID information from the logical value “0” to the logical value “1”. In the present embodiment, the magneto-optical reproduction signal M
Since the PLL clock signal CLK _PLL is pulled into the phase of O and the PLL circuit 29 is in a locked state (synchronous state), even when ID information is recorded on the magneto-optical disk 1, the PLL clock signal CLK _PLL and the magneto-optical The time difference Δ (MO-CLK _PLL ) from the reproduction signal MO becomes substantially zero. For example, the ID shown in FIG.
When information is recorded, as described later, the time difference Δt (CLK-LD) between the master clock signal CLK and the laser drive signal S26 during recording is as shown in FIG.
The result is as shown in FIG. At the time of reproduction, P
VCO drive voltage signal S29 output from LL circuit 29
Is as shown in FIG. 5 (C).

The ID information detection circuit 22 detects ID information recorded on the magneto-optical disk 1 from a change in the VCO drive voltage signal S29 based on the characteristics of the VCO drive voltage signal S29 as described above. Specifically, when the VCO drive voltage signal S29 has the waveform shown in FIG. 5C, the ID information detection circuit 22 outputs the VCO drive voltage signal S2.
A zero-cross comparison is performed to compare the amplitude level of the signal 9 with the amplitude level of zero, thereby generating an ID information reproduction signal shown in FIG.

The content reproduction circuit 21 is a PLL circuit 2
9 based on the PLL clock signal CLK _PLL
The magneto-optical reproduction signal MO from the signal generation circuit 15 is subjected to zero-cross comparison (comparison) processing, and FIG.
And a content reproduction signal S21 shown in FIG. 4 (G) is generated and output.

The sector detection circuit 19 detects the start of a sector based on the reproduction signal RF, and outputs a sector detection signal S19 to the timing generation circuit 20. Generally, magneto-optical disks, optical disks, and compact disks (CDs)
In the case of a disk, a recording mark indicating the start of a sector is formed on a track by a stamper at the time of manufacturing a disk. The sector detection circuit 19 can detect a sector by detecting the recording mark based on the reproduction signal RF.

The timing generation circuit 20 includes a sector detection signal S19 from the sector detection circuit 19, a control signal S31 from the control circuit 31, and a signal from the oscillation circuit 32 shown in FIG.
And the master clock signal CLK shown in FIG. The timing generation circuit 20 generates a clock signal S20a based on, for example, the write timing to the magneto-optical recording medium 1 indicated by the control signal S31 from the control circuit 31 and the master clock signal S32, and outputs the clock signal S20a to the laser drive signal generation circuit. 26. Further, the timing generation circuit 20 controls the write timing to the magneto-optical recording medium 1 indicated by the control signal S31 from the control circuit 31 and the master clock signal S32
, And outputs the clock signal S20b to the magnetic head drive signal generation circuit 23.

The laser drive signal generation circuit 26 generates a laser drive signal S 26 based on the clock signal S 20 a from the timing generation circuit 20 and the modulation control by the laser drive signal modulation circuit 28, and
5 is output. The laser drive circuit 25 drives the laser 8 based on the laser drive signal S26.

The laser drive signal modulation circuit 28 operates based on the master clock signal CLK from the oscillation circuit 32, and is generated by the laser drive signal generation circuit 26 so as to change the phase according to the input ID information S33. Phase modulation control is performed on the laser drive signal. The ID information detection circuit 22 detects the phase change and detects ID information based on the detection result. FIG. 3 is a waveform diagram of each signal when the phase of the laser drive signal is changed (when ID information is not added), and FIG. 4 is a case where the phase of the laser drive signal is changed (when ID information is added). 3 is a waveform diagram of each signal of FIG. Here, FIG. 3 (C) and FIG.
(C) shows a time difference Δt (CLK-LD) between the master clock signal CLK and the laser drive signal S26.

As shown in FIGS. 3C and 4C, the time difference Δt (CLK-LD) is a constant value A as shown in FIG. 3C when no phase change is given. On the other hand, when a phase change is given to the laser drive signal, FIG.
It changes as shown in (C). FIG. 4C shows a case where the ID information changes from the logical value “0” to “1” and the time difference Δt (CLK−LD) increases from the value A to the value B, for example. When the ID information changes from the logical value “1” to “0”, the time difference Δt (CLK−LD) is equal to the value B.
To the value A.

The magnetic head drive signal generation circuit 23 determines the direction of the magnetic field of the magnetic head 27 with respect to the magneto-optical recording medium 1 in accordance with the input content signal S30 with reference to the clock signal S20b from the timing generation circuit 20. Is generated to output a magnetic head drive signal S23 to the magnetic head drive circuit 24. The magnetic head 27 applies a magnetic field in a direction corresponding to the magnetic head drive circuit 24 to a predetermined position on the magneto-optical disk 1, and forms an N-pole or S-pole recording mark at a position above the Curie temperature.

Specifically, FIG. 3 (E) and FIG. 4 (E)
When the content signal has a logical value "1", a magnetic field in the first direction is applied from the magnetic head 27 to a predetermined position on the magneto-optical disk 1 to form an N-pole recording mark at that position. Then, when the content signal has the logical value "0", a magnetic field in the second direction is applied, and an S-pole recording mark is formed at the position. At this time, the recording mark formed on the magneto-optical disk 1 is the one of the master clock signal CLK.
One pulse is formed for each pulse, the magnitude of which is determined by the width and magnitude of the pulse of the master clock signal CLK, and the interval is determined by the period (frequency) of the master clock signal CLK. Specifically, the size of the recording mark increases (the radius increases) as the pulse width of the master clock signal CLK increases and as the size increases. Note that, in the case of the present embodiment, the adjacent recording marks overlap each other.

The magnetic head drive circuit 24 drives the magnetic head 27 based on the magnetic head drive signal S23 so as to generate a magnetic field in the magneto-optical recording medium 1 according to the content signal S30.

The operation of the recording / reproducing apparatus 40 will be described below. [Recording Operation] For example, a case where the content signal S30 downloaded via satellite communication or the Internet is recorded on the magneto-optical disk 1 will be described. In this case, first, a predetermined ROM (Read Only Memory) on the magneto-optical disk 1 is read.
The serial number of the disc recorded in the (ory) type recording area is read, and this is output to the laser drive signal modulation circuit 28 as ID information S33. The control circuit 31 controls the rotation of the motor 2. Then, the laser driving circuit 25 receives the laser driving signal S26.
Of the laser 8 is controlled, and the laser beam from the laser 8 is applied to the recording position on the magneto-optical disk 1 via the collimator lens 7, the beam splitter 5, and the objective lens 3. At this time, the phase of the laser drive signal S26 generated by the laser drive signal generation circuit 26 is modulated and controlled by the laser drive signal modulation circuit 28 according to the ID information S33, as described above.

Further, in parallel with the above-described laser beam irradiation operation, the following control of the magnetic head 27 is performed.
That is, in the magnetic head drive signal generation circuit 23,
On the basis of the clock signal S20b from the timing generation circuit 20, according to the input content signal S30,
The magnetic head drive signal S23 is changed so that the direction of the magnetic field with respect to the magneto-optical recording medium 1 by the magnetic head 27 is changed.
Is generated. Then, an excitation current corresponding to the magnetic head drive signal S23 from the magnetic head drive signal generation circuit 23 is supplied to the magnetic head 27 by the magnetic head drive circuit 24. The magnetic head 27 includes a magnetic head drive circuit 24
Is applied to a predetermined position on the magneto-optical disk 1 to form a recording mark magnetized to the N pole or the S pole at a position where the temperature is equal to or higher than the Curie temperature.

[Reproduction Operation] For example, an operation for reproducing a content signal recorded on the magneto-optical disk 1 through the above-described recording operation will be described. A laser beam from a laser 8 is applied to a reproduction position on the magneto-optical disk 1 via a collimator lens 7, a beam splitter 5, and an objective lens 3, and a laser beam reflected at the reproduction position is transmitted through the objective lens 3. And supplied to the beam splitter 5. Note that the intensity of the laser beam output from the laser 8 during reproduction is smaller than that during recording. In the beam splitter 5, the laser beam from the objective lens 3 is reflected and supplied to a polarization beam splitter (PBS) 9. In the polarization beam splitter 9, the reflected laser beam from the beam splitter 5 is split and supplied to the condenser lenses 10 and 12. At this time, the polarization plane of the reflected laser beam slightly rotates in the positive or negative direction with respect to the incident laser beam according to the polarities N and S of the magnetization of the magneto-optical disk 1. Therefore, when the reflected laser beam passes through the polarization beam splitter 9, the distribution amount to the photodetectors 10 and 13 differs depending on the polarities N and S.

In the photodetectors 11 and 13, FIG.
In the four divided light receiving areas A, B, C, and D shown in FIG.
The laser beams from the condenser lenses 10 and 12 are photoelectrically converted, and the currents IA ₁₁ , IB ₁₁ , IC ₁₁ , ID ₁₁ , IA ₁₃ ,
IB ₁₃ , IC ₁₃ , and ID ₁₃ are generated and output to the current-voltage conversion circuit 14.

Next, in the current-voltage conversion circuit 14, the currents IA ₁₁ , IB ₁₁ , IC ₁₁ ,
_{ID 11, IA 13, IB 13} , signals A _11, B ₁₁ with an amplitude of the voltage level corresponding to the current value of the IC _13, ID _{13,
C 11, D 11, A 13} , B 13, C 13, D 13 is generated. Next, in the signal generation circuit 15, the magneto-optical reproduction signal MO is generated based on the above equation using the signals A ₁₁ , to D ₁₁ and A _{13 to} D ₁₃ from the current-voltage conversion circuit 14. The magneto-optical reproduction signal MO is output to the content reproduction circuit 21 and the PLL circuit 29.

In the PLL circuit 29, the magneto-optical reproduction signal MO
PLL signal CLK to the phase of VFO included in
_The process of pulling in the phase of the _PLL is performed, and the VCO drive voltage signal S29 indicating the level of the VCO drive voltage is output to the ID information detection circuit 22.

Next, in the ID information detection circuit 22, as described above, from the change in the VCO drive voltage signal S29,
The ID information S22 recorded on the magneto-optical disk 1 is detected. In the content reproduction circuit 21, a PLL
Based on the PLL clock signal CLK _PLL from the circuit 29 as a reference, the magneto-optical reproduction signal MO from the signal generation circuit 15 is subjected to zero-cross comparison (comparison) processing to generate a content reproduction signal S21. At this time, when the content reproduction signal S21 is recorded on another magneto-optical disk using a recording device, the ID information S22 can be used for preventing unauthorized copying.

As described above, according to the recording / reproducing apparatus 40, the content signal including the ID information is transmitted to the magneto-optical disk so that the content signal obtained by reproducing the magneto-optical disk 1 does not include the ID information. 1 can be recorded. Therefore, when a content signal obtained by reproducing the magneto-optical disk 1 is recorded on another magneto-optical recording medium,
The ID information of the magneto-optical disk 1 is not recorded on the magneto-optical recording medium. Therefore, it is possible to suppress unauthorized use of the content signal by using the characteristic.

Second Embodiment In the first embodiment described above, the time constant of the phase change of the magneto-optical reproduction signal MO is sufficiently smaller than the performance of the PLL circuit 29, and the PLL circuit 29 Although the case of following the phase change has been described as an example, in the present embodiment, the time constant of the phase change of the magneto-optical reproduction signal MO is equal to that of the PLL circuit 29.
The case where the PLL circuit 29 does not follow the phase change of the magneto-optical reproduction signal MO, which is large for the performance of FIG.

FIG. 6 shows a recording / reproducing apparatus 140 according to this embodiment.
FIG. As shown in FIG.
0 denotes a motor 2, a laser 8, photodetectors 11 and 13, a current-voltage conversion circuit 14, a signal generation circuit 15, and a phase compensation circuit 1.
6, two-axis drive circuit 17, sector detection circuit 19, timing generation circuit 20, content reproduction circuit 21, ID information detection circuit 122, magnetic head drive signal generation circuit 23, magnetic head drive circuit 24, laser drive circuit 25, laser drive It has a signal generation circuit 26, a magnetic head 27, a laser drive signal modulation circuit 28, a PLL circuit 29, an optical system 30, and a control circuit 31. 6, the components denoted by the same reference numerals as those in FIG. 1 are the same as the components denoted by the same reference numerals described in the first embodiment. As shown in FIG. 6, in the recording / reproducing device 140, the configuration and function of the ID information detecting circuit 122 are different from those of the above-described ID information detecting circuit 22 of the recording / reproducing device 40 of the first embodiment.

FIG. 7 is a configuration diagram of the ID information detection circuit 122. As shown in FIG. 7, the ID information detection circuit 122
Are, for example, a time difference detection circuit 50 and an absolute value generation circuit 5
1, a comparison circuit 52 and an NRZI processing circuit 53 are provided. In this embodiment, when the ID information is recorded, the PLL circuit 29 does not enter the locked state, and the magneto-optical reproduction signal MO from the signal generation circuit 15 and the PLL clock signal CLK _PLL output from the PLL circuit 29 are output. Since a time difference (PLL error) occurs between the two, the ID information is reproduced using the time difference.

The time difference detection circuit 50 receives the magneto-optical reproduction signal MO from the signal generation circuit 15 shown in FIG.
9, the PLL clock signal CLK _CLK from FIG. 9 is input, and the time difference between them is detected to indicate the time difference.
The time difference detection signal Δ (MO-CL having the waveform shown in FIG.
K _PLL ) and outputs it to the absolute value generation circuit 51.

The absolute value generation circuit 51 includes a time difference detection circuit 5
Time difference detection signal Δ (MO-CLK _PLL ) input from 0
The absolute value signal ABSΔt having the waveform shown in FIG. 8D, for example, indicating the absolute value of the time difference indicated by is generated and output to the comparison circuit 52.

The comparing circuit 52 compares the amplitude of the absolute value signal ABSΔt input from the absolute value generating circuit 51 with, for example, the signal shown in FIG.
A comparison is made with a predetermined threshold L shown in (D). Then, the comparison circuit 52 goes to a high level when the amplitude of the absolute value signal ABSΔt is equal to or larger than the threshold value L, and goes to a low level when the amplitude of the absolute value signal ABSΔt is smaller than the threshold value L. A comparison result signal CMP having the waveform shown in E) is generated and output to the NRZI processing circuit 53.

The NRZI processing circuit 53 converts the comparison result signal CMP input from the comparison circuit 52 into an NRZI (Non Return
(Zero Level Inverse) to generate ID information S122 and output it.

The operation of the ID information detection circuit 122 will be described below. The magneto-optical reproduction signal MO from the signal generation circuit 15 shown in FIG. 6 and the PLL clock signal CLK _CLK from the PLL circuit 29 are input to the time difference detection circuit 50. In the time difference detection circuit 50, the magneto-optical reproduction signals MO and PL
A time difference from the L clock signal CLK _CLK is detected, and a time difference detection signal Δ (MO-CLK _PLL ) indicating the time difference is output to the absolute value generation circuit 51. Next, in the absolute value generation circuit 51, an absolute value signal ABSΔt indicating the absolute value of the time difference indicated by the time difference detection signal Δ (MO-CLK _PLL ) input from the time difference detection circuit 50 is generated, and the absolute value signal ABSΔt is compared with the comparison circuit. 52. Next, the comparison circuit 52 compares the amplitude of the absolute value signal ABSΔt with a predetermined threshold L. In the comparison circuit 52, when the amplitude of the absolute value signal ABSΔt is equal to or larger than the threshold value L, the comparison result signal CMP goes high when the amplitude of the absolute value signal ABSΔt is smaller than the threshold value L. Is generated and output to the NRZI processing circuit 53. Next, in the NRZI processing circuit 53, the comparison result signal CMP from the comparison circuit 52 is NRZI-encoded to generate ID information S122.

The recording operation and the reproducing operation of the recording / reproducing apparatus 140 shown in FIG.
5, except that it does not follow the phase change of the magneto-optical reproduction signal MO from Step 5 and the processing in the ID information detection circuit 122.
This is the same as the recording / reproducing device 40 of the first embodiment described above.

The recording / reproducing device 140 described above also
The same effects as those of the recording / reproducing device 40 of the first embodiment described above can be obtained.

Third Embodiment In the above embodiment, the case where the ID information is recorded by modulating the phase of the laser drive signal has been exemplified. In the present embodiment, the height of the pulse of the laser drive signal is modulated. A case where ID information is recorded will be described.

FIG. 9 shows a recording / reproducing apparatus 240 of this embodiment.
FIG. As shown in FIG.
0 denotes a motor 2, a laser 8, photodetectors 11 and 13, a current-voltage conversion circuit 14, a signal generation circuit 15, and a phase compensation circuit 1.
6, two-axis drive circuit 17, sector detection circuit 19, timing generation circuit 20, content reproduction circuit 21, ID information detection circuit 222, magnetic head drive signal generation circuit 23, magnetic head drive circuit 24, laser drive circuit 25, laser drive It has a signal generation circuit 226, a magnetic head 27, a laser drive signal modulation circuit 228, a PLL circuit 29, an optical system 30, and a control circuit 31. In FIG. 9, the components denoted by the same reference numerals as those in FIG. 1 are the same as the components denoted by the same reference numerals described in the first embodiment. As shown in FIG. 9, in the recording / reproducing apparatus 140, the configuration and function of the ID information detecting circuit 222, the laser drive signal generating circuit 226, and the laser drive signal modulating circuit 228 are the same as those of the recording / reproducing apparatus 40 of the first embodiment. It is different from the ID information detection circuit 22, the laser drive signal generation circuit 26, and the laser drive signal modulation circuit 28.

The laser drive signal modulation circuit 228 operates based on the master clock signal CLK from the oscillation circuit 32, and changes the pulse height in accordance with the input ID information S33. Performs pulse-height modulation control on the laser drive signal generated by. Specifically, the laser drive signal modulation circuit 228 sets the ID information to the logical value “1” (high level) in a state where the pulse period is the same, for example, as shown in FIGS. When it indicates, the pulse height of the laser drive signal S226 is set to L1, and when the ID information indicates a logical value "0" (low level), the pulse height of the laser drive signal S226 is set to L2 smaller than L1.

The laser drive signal generation circuit 226 generates a laser drive signal S226 based on the clock signal S20a from the timing generation circuit 20 and the pulse height modulation control by the laser drive signal modulation circuit 228, and outputs the laser drive signal S226. Output to the drive circuit 25. Laser drive circuit 25
Drives the laser 8 based on the laser drive signal S226. At this time, when the ID information to be recorded has the logical value “1”, the power of the laser beam emitted from the laser 8 to the magneto-optical disk 1 is greater than when the logical value is “0”. Become. Accordingly, as shown in FIG. 10E, the size of the recording mark formed on the magneto-optical disk 1 is determined when the pulse height of the laser drive signal S226 is L1 (the ID information to be recorded is a logical value). "1"),
When the pulse height of the laser drive signal S226 is L2 (when the ID information to be recorded has the logical value "0"), it becomes larger. In the present embodiment, asymmetry (Asynm) detected by an ID information detection circuit 122 described later is used.
(etry) ID information S33 whose ID information is uniquely determined by the value is used.

The ID information detection circuit 222 detects the ID information S222 recorded in the magneto-optical reproduction signal MO from the signal generation circuit 15 and outputs the same. In the ID information detection circuit 222, the magneto-optical reproduction signal MO
Is monitored, and the number of locations showing a plurality of predetermined amplitude values is counted. Then, a central amplitude value is calculated using the count value, and the calculated amplitude value is set as an asymmetry value A, for example, as shown in FIG. The ID information detection circuit 222 has, for example, a table indicating a correspondence between the asymmetry value and the ID information, and obtains ID information S222 corresponding to the calculated asymmetry value A using the table. Is output. Note that I
When the asymmetry value A when the D information is not recorded is 0
So that

The recording operation and the reproducing operation of the recording / reproducing device 240 shown in FIG. 9 are performed by the laser driving signal modulating circuit 228 for modulating the laser driving signal and the ID information detecting circuit 2.
22 is the same as the recording / reproducing device 40 of the first embodiment described above, except for the ID information detection process in 22.

The recording / reproducing device 240 described above also
The same effects as those of the recording / reproducing device 40 of the first embodiment described above can be obtained.

The recording / reproducing device 24 of the third embodiment described above
0 can be modified as shown below. [First Modification] For example, in the above-described third embodiment,
Although the case where the pulse height of the laser drive signal S226 is changed in accordance with the logical value of the ID information has been exemplified, FIG.
As shown in (C), the pulse width of the laser drive signal S226 may be changed (modulated) according to the logical value of the ID information. Specifically, the laser drive signal modulation circuit 228 sets the ID information to the logical value “1” (high level) in the state where the pulse period is the same as shown in FIGS. 11A and 11C, for example. The laser drive signal S2
26 is set to W1, and the ID information is a logical value “0”.
When (low level) is indicated, the pulse width of the laser drive signal S226 is set to W2 smaller than W1. Even in this case,
When the ID information to be recorded has a logical value of “1”, the laser 8 emits more light from the magneto-optical disk 1 than the logical value of “0”.
Power of the laser beam applied to the laser beam increases. Therefore, as shown in FIG. 11E, the size of the recording mark formed on the magneto-optical disk 1 is equal to the pulse width W1 of the laser drive signal S226 (the ID to be recorded).
When the information has the logical value “1”), the laser drive signal S22
6 is larger than when the pulse width is W2 (when the ID information to be recorded has the logical value “0”). The configuration and function of the ID information detection circuit 222 are the same as those described above.

[Second Modification] In the above-described third embodiment, a pulse signal is exemplified as the laser drive signal S226.
A non-pulse signal as shown in (C) may be used. In this case, as in the case of FIG.
As shown in FIGS. 2A and 2C, when the ID information indicates a logical value “1” (high level), the laser drive signal S2
The level of the laser drive signal S226 is set to L2 smaller than L1 when the ID information indicates the logical value "0" (low level). Even in this case, if the ID information to be recorded has the logical value “1”, the logical value “0”
The power of the laser beam emitted from the laser 8 to the magneto-optical disk 1 is larger than in the case of (1). Accordingly, the size of the recording mark formed on the magneto-optical disk 1 is, as shown in FIG.
At the level L1 of H.226 (when the ID information to be recorded has a logical value of "1"), at the level L2 of the laser drive signal S226 (when the ID information to be recorded has a logical value of "0") It will be larger than that. The configuration and function of the ID information detection circuit 222 are the same as those described above.

Fourth Embodiment The above-described embodiment is basically similar to the first and third embodiments described above.
Same as the recording / reproducing apparatus of the embodiment, except that in the laser drive signal modulation circuit, the logical product of the content signal to be recorded and the ID information is calculated, and based on the logical product, the pulse height of the laser drive signal and The difference is that the width and the like are modulated. FIG. 13 is a configuration diagram of the recording / reproducing device 340 of the present embodiment. As shown in FIG.
Are a motor 2, a laser 8, photodetectors 11 and 13, a current-voltage conversion circuit 14, a signal generation circuit 15, and a phase compensation circuit 1.
6, two-axis drive circuit 17, sector detection circuit 19, timing generation circuit 20, content reproduction circuit 21, ID information detection circuit 222, magnetic head drive signal generation circuit 23, magnetic head drive circuit 24, laser drive circuit 25, laser drive It has a signal generation circuit 326, a magnetic head 27, a laser drive signal modulation circuit 328, a PLL circuit 29, an optical system 30, and a control circuit 31. 13, FIG. 1 and FIG.
The components denoted by the same reference numerals as those described above are the same as the components denoted by the same reference numerals described in the above-described first and third embodiments. As shown in FIG.
The configuration and function of the laser drive signal generation circuit 326 and the laser drive signal modulation circuit 328 are different from those of the first embodiment.
This is different from the embodiments and the third embodiment.

FIG. 14 shows a laser drive signal modulation circuit 328.
FIG. As shown in FIG. 14, the laser drive signal modulation circuit 328 includes a logical operation circuit 350 and a modulation circuit 351. The logical operation circuit 350 is, for example, as shown in FIG.
The ID information S33 shown in FIG. 5A and the content signal S30 shown in FIG. 15B are input, the logical product of them is calculated, and the signal S350 indicating the calculation result is converted to the modulation circuit 3
51. The modulation circuit 351 operates on the basis of the master clock signal CLK from the oscillation circuit 32, and changes the laser drive signal generated by the laser drive signal generation circuit 326 so as to change the pulse height in accordance with the input signal S350. On the other hand, pulse height modulation control is performed. Specifically, the laser drive signal modulation circuit 328 is configured as shown in FIG.
As shown in (D), with the same pulse period,
When the signal S350 indicates the logical value "1" (high level), the pulse height of the laser drive signal S326 is set to L1, and when the signal S350 indicates the logical value "0" (low level), the pulse of the laser drive signal S326 is set. The height is set to L2 smaller than L1.

The laser drive signal generation circuit 326 generates a laser drive signal S326 based on the clock signal S20a from the timing generation circuit 20 and the pulse height modulation control by the laser drive signal modulation circuit 328, and generates the laser drive signal S326. Output to the drive circuit 25. Laser drive circuit 25
Drives the laser 8 based on the laser drive signal S226.

The processing in the ID information detection circuit 222 is as follows.
This is the same as in the third embodiment described above. The recording operation and the reproducing operation of the recording / reproducing apparatus 340 shown in FIG. 13 are the same as those of the first embodiment except for the laser drive signal modulation process in the laser drive signal modulation circuit 228 and the ID information detection process in the ID information detection circuit 222. This is the same as the recording / reproducing device 40 of the embodiment.

The recording / reproducing device 340 described above also
The same effects as those of the recording / reproducing device 40 of the first embodiment described above can be obtained.

The recording / reproducing apparatus 34 of the fourth embodiment described above.
0 is, as described above, in the logical operation circuit 350
In addition to calculating the logical product of the content signal S30 and the ID information S33, for example, another logical operation such as a logical sum may be performed. Further, as described above, the recording / reproducing device 340 of the fourth embodiment may change the pulse amplitude of the laser drive signal in addition to changing the pulse height of the laser drive signal in accordance with the signal S350. Further, a non-pulse signal may be used as the laser drive signal, and the level of the non-pulse signal may be changed according to the signal S350. Further, the phase modulation may be controlled based on the result of the logical operation described above.
In the above-described fourth embodiment, for example, in the logical operation circuit 350 shown in FIG. 14, for example, as shown in FIG.
When the logical value 33 is “1”, the pulse height of the laser drive signal S326 shown in FIG. 16D is set to L1, and in other cases, the pulse height of the laser drive signal S326 is set to L2. The calculation may be performed.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the laser driving circuit 2
The example in which the ID information is recorded on the magneto-optical disk 1 by modulating the laser drive signal output to the MPU 5 has been described. For example, in the magnetic head drive signal generation circuit, the ID information that can be removed during reproduction (demodulation) is converted to ID information. Encoding (partial response processing) for adding the corresponding intersymbol interference may be performed on the content signal, and a magnetic head drive signal corresponding to the encoded content signal may be generated. Then, at the time of reproduction, for example, ID information is detected from the level shift of the partial response obtained from the magneto-optical reproduction signal MO reproduced from the magneto-optical disk 1.

The magneto-optical recording apparatus in this case includes, for example, a laser for irradiating the magneto-optical disk 1 with a laser beam, a magnetic head for supplying a magnetic field according to a magnetic head drive signal to the laser beam irradiation position, A laser drive signal generation circuit for generating the laser drive signal so that the magnetic head supplies a magnetic field in a direction corresponding to a content signal; and the magnetic head for generating intersymbol interference corresponding to ID information of the magneto-optical disk 1 A drive signal modulation circuit for modulating the drive signal. Further, the magneto-optical reproducing device includes, for example, a laser for irradiating the magneto-optical disc 1 with a laser beam, a photodetector for receiving reflected light of the laser beam from the magneto-optical disc 1, and a light-receiving result of the photodetector. A signal generation circuit for generating a magneto-optical reproduction signal; and an information detecting circuit for detecting ID information in the magneto-optical reproduction signal based on a state of intersymbol interference in the magneto-optical reproduction signal.

[0106]

According to the present invention, there is provided a magneto-optical recording apparatus for recording a second information together with the first information in a magneto-optical recording medium in a state where the second information cannot be reproduced by a conventional ordinary magneto-optical recording medium. We can provide those methods. Further, according to the present invention, it is possible to provide a magneto-optical reproducing apparatus for reproducing the second information thus recorded independently of the reproduction of the first information, and a method thereof. As a result, according to the present invention, illegal duplication of content can be prevented by using the first information as content information and the second information as information for preventing illegal duplication of the content signal. become.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a partial configuration diagram of the photodetector shown in FIG.

FIG. 3 is a diagram showing a waveform of each signal in the recording / reproducing apparatus shown in FIG. 1 when ID information is not recorded.

FIG. 4 is a diagram showing a case where ID information is recorded in FIG.
FIG. 3 is a diagram showing waveforms and the like of each signal in the recording / reproducing apparatus shown in FIG.

FIG. 5 is a diagram for explaining a process in the ID information detection circuit shown in FIG. 1;

FIG. 6 is a configuration diagram of a recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of the ID information detection circuit shown in FIG. 6;

FIG. 8 is a waveform diagram of each signal shown in FIG. 7;

FIG. 9 is a configuration diagram of a recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 10 is a diagram showing waveforms and the like of each signal shown in FIG. 9;

11 is a diagram showing a waveform diagram and the like of each signal in a first modified example of the recording / reproducing apparatus shown in FIG. 9;

12 is a diagram showing a waveform diagram and the like of each signal in a second modification of the recording and reproducing device shown in FIG. 9;

FIG. 13 is a configuration diagram of a recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 14 is a configuration diagram of the laser drive signal modulation circuit shown in FIG. 13;

15 is a diagram showing a waveform diagram and the like of each signal in the recording / reproducing apparatus shown in FIG. 13;

FIG. 16 is a diagram for explaining a modification of the recording / reproducing device according to the fourth embodiment of the present invention.

[Explanation of symbols]

1: magneto-optical disk, 2: motor, 3: objective lens,
5, 9 ... beam splitter, 11, 13 ... photodetector, 1
4 current-voltage conversion circuit, 15 signal generation circuit, 16 phase compensation circuit, 17 two-axis drive circuit, 19 sector detection circuit, 20 timing generation circuit, 21 content reproduction circuit, 22, 122, 222 ... ID information detection circuit, 23
... Magnetic head drive signal generation circuit, 24 ... Magnetic head drive circuit, 25 ... Laser drive circuit, 26, 126, 226
326: laser drive signal generation circuit, 28, 128, 22
8,328 ... Laser drive signal modulation circuit, 31 ... Control circuit, 32 ... Oscillation circuit

Claims (48)

[Claims] A light source for irradiating a light beam to a magneto-optical recording medium based on the driving signal; a driving signal generating circuit for generating the driving signal; and a first information to be recorded on the magneto-optical recording medium. A magnetic head for applying a magnetic field to the irradiation position of the light beam on the magneto-optical recording medium; and a drive signal modulation circuit for modulating the drive signal in accordance with second information recorded on the magneto-optical recording medium. Magneto-optical recording device. 2. A light source for irradiating a light beam to a magneto-optical recording medium based on a driving pulse signal, a driving signal generating circuit for generating the driving pulse signal, and a first information to be recorded on the magneto-optical recording medium. A magnetic head for applying a corresponding magnetic field to an irradiation position of the light beam on the magneto-optical recording medium; and a driving signal for modulating a phase of the driving pulse signal in accordance with second information recorded on the magneto-optical recording medium. A magneto-optical recording device having a modulation circuit. 3. The magneto-optical recording apparatus according to claim 2, wherein said second information is information used for controlling at least one of recording and reproduction of said first information. 4. The second information comprises a first logical value and a second logical value, and the drive signal modulating circuit is configured to output the second information in accordance with the first logical value of the second information. Shifting the phase of the drive pulse signal in the first direction with respect to the phase of the master clock signal;
3. The magneto-optical recording apparatus according to claim 2, wherein a phase of a pulse of the drive pulse signal is shifted in a second direction with respect to a phase of the master clock signal according to the second logical value of the second information. 5. A light source for irradiating a light beam to a magneto-optical recording medium based on a driving pulse signal, a driving signal generating circuit for generating the driving pulse signal, and a first information to be recorded on the magneto-optical recording medium. A magnetic head for applying a corresponding magnetic field to an irradiation position of the light beam on the magneto-optical recording medium, and modulating a pulse height of the drive pulse signal in accordance with second information recorded on the magneto-optical recording medium A magneto-optical recording device having a driving signal modulation circuit. 6. The second information comprises a first logical value and a second logical value, and the drive signal modulating circuit controls the drive signal modulation circuit according to the first logical value of the second information. The pulse of the drive pulse signal is set to a first height, and the pulse of the drive pulse signal is set to a second height according to the second logical value of the second information.
3. The magneto-optical recording device according to claim 1. 7. A light source for irradiating a light beam to a magneto-optical recording medium based on a driving pulse signal, a driving signal generating circuit for generating the driving pulse signal, and a first information to be recorded on the magneto-optical recording medium. A magnetic head for applying a corresponding magnetic field to an irradiation position of the light beam on the magneto-optical recording medium, and modulating a pulse width of the drive pulse signal in accordance with second information recorded on the magneto-optical recording medium A magneto-optical recording device having a drive signal modulation circuit. 8. The second information comprises a first logical value and a second logical value, and the drive signal modulating circuit is configured to output the second information in accordance with the first logical value of the second information. 8. The magneto-optical device according to claim 7, wherein the width of the drive pulse signal is set to a first width, and the width of the pulse of the drive pulse signal is set to a second width according to the second logical value of the second information. Recording device. 9. A light source for irradiating a light beam to a magneto-optical recording medium based on a driving signal, a driving signal generating circuit for generating the driving signal, and a first information recorded on the magneto-optical recording medium A magnetic head for applying a magnetic field to the irradiation position of the light beam on the magneto-optical recording medium; a driving signal modulation circuit for modulating the amplitude of the driving signal in accordance with second information recorded on the magneto-optical recording medium; A magneto-optical recording device having: 10. The second information includes a first logical value and a second logical value.
The drive signal modulation circuit sets the amplitude of the drive signal to a first level in accordance with the first logical value of the second information, and sets the second level of the second information 10. The magneto-optical recording apparatus according to claim 9, wherein the amplitude of the drive signal is set to the second level in accordance with the logical value of the above. 11. A light source that irradiates a light beam to a magneto-optical recording medium based on a driving signal, a driving signal generating circuit that generates the driving signal, and a first information that is recorded on the magneto-optical recording medium. A magnetic head for applying a magnetic field to an irradiation position of the light beam on the magneto-optical recording medium; a second information used to control at least one of recording and reproduction of the first information; A magneto-optical recording device comprising: a logical operation on information to generate third information; and a drive signal modulation circuit for modulating the drive signal in accordance with the third information. 12. A light source for irradiating a light beam to a magneto-optical recording medium, a magnetic head for supplying a magnetic field corresponding to a drive signal to an irradiation position of the light beam, A magneto-optical recording device comprising: a drive signal generation circuit that generates a drive signal so as to supply a magnetic field; and a drive signal modulation circuit that modulates the drive signal so as to generate intersymbol interference according to second information. 13. A light source for irradiating a light beam to a magneto-optical recording medium, a light receiving circuit for receiving reflected light of the light beam from the magneto-optical recording medium, and a magneto-optical device based on a light receiving result of the light receiving circuit. A signal generation circuit for generating a reproduction signal, and a PLL for performing phase synchronization processing on the magneto-optical reproduction signal
A magneto-optical reproducing device comprising: a circuit; and an information detecting circuit for detecting information in the magneto-optical reproducing signal based on a drive voltage signal of a voltage-controlled oscillation circuit of the PLL circuit. 14. The magneto-optical reproducing apparatus according to claim 13, further comprising a reproducing circuit for generating a reproducing signal based on the amplitude of the magneto-optical reproducing signal. 15. The magneto-optical reproducing apparatus according to claim 13, wherein the phase change of the magneto-optical reproducing signal has a time constant that can be followed by the phase processing of the PLL circuit. 16. The magneto-optical reproducing apparatus according to claim 14, wherein the information is information used for controlling at least one of recording and reproduction of the reproduction signal. 17. A light source for irradiating a light beam to a magneto-optical recording medium, a light receiving circuit for receiving reflected light of the light beam from the magneto-optical recording medium, and a magneto-optical device based on a light receiving result of the light receiving circuit. A signal generation circuit for generating a reproduction signal, and a PLL for performing phase synchronization processing on the magneto-optical reproduction signal
A magneto-optical signal comprising: a circuit; and an information detecting circuit for detecting information in the magneto-optical reproducing signal based on a time difference between the magneto-optical reproducing signal and a PLL clock signal output from a voltage-controlled oscillation circuit of the PLL circuit. Playback device. 18. A time difference detection circuit for detecting a time difference between the magneto-optical reproduction signal and a PLL clock signal output from a voltage controlled oscillation circuit of the PLL circuit to generate a time difference signal; A comparison circuit that generates a comparison result signal by comparing the amplitude of the time difference detection signal with a predetermined value, and an encoding circuit that performs NRZI encoding on the comparison signal and reproduces information in the magneto-optical reproduction signal. 18. The magneto-optical reproducing device according to item 17. 19. The magneto-optical reproducing apparatus according to claim 17, further comprising a reproducing circuit for generating a reproducing signal based on the amplitude of the magneto-optical reproducing signal. 20. The magneto-optical reproducing apparatus according to claim 17, wherein the phase change of the magneto-optical reproducing signal has a time constant that cannot be followed by the phase processing of the PLL circuit. 21. A light source for irradiating a light beam to a magneto-optical recording medium, a light receiving circuit for receiving reflected light of the light beam from the magneto-optical recording medium; A signal generation circuit that generates a reproduction signal; and an information detection circuit that calculates a center value of the amplitude of the magneto-optical reproduction signal and detects information in the magneto-optical reproduction signal based on the calculated center value. Magneto-optical reproducing device. 22. The magneto-optical reproducing apparatus according to claim 21, further comprising a reproducing circuit for generating a reproducing signal based on the amplitude of the magneto-optical reproducing signal. 23. A light source for irradiating a light beam to a magneto-optical recording medium, a light receiving circuit for receiving reflected light of the light beam from the magneto-optical recording medium, and a magneto-optical device based on a light receiving result of the light receiving circuit. A signal generation circuit for generating a reproduction signal, and based on a state of intersymbol interference in the magneto-optical reproduction signal,
A magneto-optical reproducing device comprising: an information detecting circuit for detecting information in the magneto-optical reproducing signal. 24. The magneto-optical reproducing apparatus according to claim 23, further comprising a reproducing circuit for generating a reproducing signal based on the amplitude of the magneto-optical reproducing signal. 25. Irradiation of a light beam on a magneto-optical recording medium based on a drive signal, and irradiation of the light beam on the magneto-optical recording medium with a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium. A magneto-optical recording method, wherein the method is applied to a position and modulates the drive signal according to second information to be recorded on the magneto-optical recording medium. 26. A light beam is applied to a magneto-optical recording medium based on a drive pulse signal, and a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium is applied to the light beam on the magneto-optical recording medium. A magneto-optical recording method, wherein the method is applied to an irradiation position, and modulates the phase of the drive pulse signal according to second information to be recorded on the magneto-optical recording medium. 27. The magneto-optical recording method according to claim 26, wherein the second information is information used to control at least one of recording and reproduction of the first information. 28. The method according to claim 28, wherein the second information includes a first logical value and a second logical value.
The drive signal modulation circuit shifts the phase of the pulse of the drive pulse signal in the first direction with respect to the phase of the master clock signal according to the first logical value of the second information. Shifted to
27. The magneto-optical recording method according to claim 26, wherein a phase of a pulse of the drive pulse signal is shifted in a second direction with respect to a phase of the master clock signal according to the second logical value of the second information. 29. A method for irradiating a magneto-optical recording medium with a light beam based on a drive pulse signal, and applying a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium to the light beam on the magneto-optical recording medium. A magneto-optical recording method, wherein the method is applied to an irradiation position, and modulates a pulse height of the drive pulse signal according to second information to be recorded on the magneto-optical recording medium. 30. The second information comprises a first logical value and a second logical value.
The pulse of the drive pulse signal is set to a first height in accordance with the first logical value of the second information, and is set in accordance with the second logical value of the second information. 30. The magneto-optical recording method according to claim 29, wherein the pulse of the drive pulse signal is set to a second height. 31. A light beam is applied to a magneto-optical recording medium based on a drive pulse signal, and a magnetic field according to first information to be recorded on the magneto-optical recording medium is applied to the light beam on the magneto-optical recording medium. A magneto-optical recording method, wherein the method is applied to an irradiation position, and modulates a pulse width of the drive pulse signal according to second information to be recorded on the magneto-optical recording medium. 32. The second information comprises a first logical value and a second logical value.
The width of the drive pulse signal is set to a first width according to the first logical value of the second information, and the width of the drive pulse signal is set to a first width according to the second logical value of the second information. 32. The magneto-optical recording method according to claim 31, wherein a pulse width of the drive pulse signal is set to a second width. 33. Irradiation of a light beam on a magneto-optical recording medium based on a drive signal, and irradiation of the light beam on the magneto-optical recording medium with a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium. A magneto-optical recording method, wherein the amplitude is applied to a position and the amplitude of the drive signal is modulated according to second information to be recorded on the magneto-optical recording medium. 34. The second information includes a first logical value and a second logical value.
The amplitude of the drive signal is set to the first level according to the first logical value of the second information, and the amplitude is set to the first level according to the second logical value of the second information. The magneto-optical recording method according to claim 33, wherein the amplitude of the drive signal is set to the second level. 35. Irradiation of a light beam on a magneto-optical recording medium based on a drive signal, and irradiation of the light beam on the magneto-optical recording medium with a magnetic field corresponding to first information to be recorded on the magneto-optical recording medium. Applied to a position to generate third information by performing a logical operation on the second information and the first information used to control at least one of recording and reproduction of the first information; A magneto-optical recording method for modulating the drive signal according to third information. 36. A method for irradiating a magneto-optical recording medium with a light beam, supplying a magnetic field according to a drive signal to an irradiation position of the light beam, and causing the magnetic head to supply a magnetic field in a direction according to the first information. A magneto-optical recording method for generating a driving signal and modulating the driving signal so as to cause intersymbol interference according to second information. 37. Irradiating a magneto-optical recording medium with a light beam, receiving reflected light of the light beam from the magneto-optical recording medium, generating a magneto-optical reproduction signal based on the light receiving result, A magneto-optical reproduction method for performing phase synchronization processing on a magnetic reproduction signal using a PLL circuit, and detecting information in the magneto-optical reproduction signal based on a drive voltage signal of a voltage-controlled oscillation circuit of the PLL circuit. 38. The magneto-optical reproducing method according to claim 37, wherein a reproducing signal is generated based on the amplitude of the magneto-optical reproducing signal. 39. The magneto-optical reproducing method according to claim 37, wherein the phase change of the magneto-optical reproducing signal has a time constant that can be followed by the phase processing of the PLL circuit. 40. A magneto-optical reproducing method according to claim 38, wherein said information is information used for controlling at least one of recording and reproduction of said first reproduction signal. 41. A method for irradiating a magneto-optical recording medium with a light beam, receiving reflected light of the light beam from the magneto-optical recording medium, and generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit. Performing a phase synchronization process on the magneto-optical reproduction signal using a PLL circuit, based on a time difference between the magneto-optical reproduction signal and a PLL clock signal output from a voltage controlled oscillation circuit of the PLL circuit. A magneto-optical reproduction method for detecting information in a magnetic reproduction signal. 42. A time difference between the magneto-optical reproduction signal and a PLL clock signal output from a voltage controlled oscillation circuit of the PLL circuit to generate a time difference signal, and the amplitude of the time difference detection signal is set to a predetermined value. 42. The magneto-optical reproducing method according to claim 41, wherein a comparison result signal is generated by performing comparison, and the information in the magneto-optical reproducing signal is reproduced by performing NRZI encoding on the comparison signal. 43. The magneto-optical reproducing method according to claim 41, wherein a reproducing signal is generated based on the amplitude of the magneto-optical reproducing signal. 44. The magneto-optical reproducing method according to claim 41, wherein the phase change of the magneto-optical reproducing signal has a time constant that cannot be followed by the phase processing of the PLL circuit. 45. A method for irradiating a magneto-optical recording medium with a light beam, receiving reflected light of the light beam from the magneto-optical recording medium, and generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit. A magneto-optical reproducing method for calculating a center value of the amplitude of the magneto-optical reproducing signal and detecting information in the magneto-optical reproducing signal based on the calculated center value; 46. The magneto-optical reproducing method according to claim 45, wherein a reproducing signal is generated based on the amplitude of the magneto-optical reproducing signal. 47. A method for irradiating a light beam to a magneto-optical recording medium, receiving reflected light of the light beam from the magneto-optical recording medium, and generating a magneto-optical reproduction signal based on a light receiving result of the light receiving circuit. Based on the state of intersymbol interference in the magneto-optical reproduction signal,
A magneto-optical reproducing method for detecting information in the magneto-optical reproducing signal. 48. The magneto-optical reproducing method according to claim 47, wherein a reproducing signal is generated based on the amplitude of the magneto-optical reproducing signal.