JPH11162031A - Optical disk, method for recording/reproducing optical disk draw information, optical disk reproducing device, optical disk recording/reproducing device, optical disk draw information recorder and optical disk recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an optical disk having DRAW information usable for copy- right protection such as copy prevention and unfair use prevention of software, etc. SOLUTION: A recording layer 213 is formed on a disk substrate 211 through a dielectric layer 212. A middle dielectric layer 214, a reflection layer 215 are laminated sequentially on the recording layer 213, and further, an overcoat layer 216 is formed on it. Plural pieces of BCA (one system of DRAW type discriminative information) parts 220a, 220b are recorded in the disk circumferential direction on the recording layer 213. These BCA parts 220a, 220b are recorded by lowering perpendicular magnetic anisotropy. When reproduced, the DRAW type information is detected by a differential signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk capable of recording, reproducing, and erasing information, and more particularly, to an optical disk and an optical disk having additional recordable information that can be used for copyright protection such as prevention of duplication and unauthorized use of software. More particularly, the present invention relates to a recording method and a reproducing method of additional recording information, an optical disk reproducing apparatus, an optical disk recording and reproducing apparatus, an optical disk additional recording information recording apparatus, and an optical disk recording apparatus.

[0002]

2. Description of the Related Art In recent years, with the rapid increase in information processing volume and information processing speed due to the development of electronic computers and information processing systems, and digitalization of audio and video information, low-cost, large-capacity, and high-speed access is possible. Auxiliary storage devices and their recording media, especially optical disks, are rapidly spreading.

The basic structure of a conventional optical disk is as follows. That is, the recording layer is formed on the disk substrate via the dielectric layer. An intermediate dielectric layer and a reflective layer are sequentially formed on the recording layer, and an overcoat layer is further formed thereon.

[0004] The operation of the optical disk having the above configuration will be described below. In the case of an optical disk using a perpendicular magnetization film having a magneto-optical effect in the recording layer, information is recorded and erased by irradiating a laser beam to the recording layer locally at a temperature where the coercive force is lower than the compensation temperature or near the Curie temperature. Heating is performed at a temperature higher than the temperature, the coercive force of the recording layer in the irradiated portion is reduced, and the recording layer is magnetized in the direction of the external magnetic field (information is recorded by so-called "thermomagnetic recording"). Further, when reproducing the recording signal, the recording layer is irradiated with a laser beam having a smaller intensity than the laser beam at the time of recording and erasing, and depending on the recording state of the recording layer, ie, the direction of magnetization, reflected light or transmitted light. This is performed by detecting a situation in which the plane of polarization rotates (this rotation occurs based on a magneto-optical effect such as the so-called Kerr effect or Faraday effect) as a change in light intensity using an analyzer. In this case, a magnetic material having perpendicular magnetic anisotropy is used for the recording layer of the optical disc in order to perform high-density recording by reducing interference between magnetizations in opposite directions.

[0005] Further, as a configuration of a recording layer, a configuration in which a plurality of magnetic thin films having different materials or compositions are sequentially laminated while being exchange-coupled or magnetostatically coupled is used.
In some cases, a reproduced signal is detected by increasing a signal level during information reproduction.

As a material for the recording layer, a material capable of recording information by inducing a local temperature rise or a chemical change due to light absorption upon irradiation with a laser beam is used. A local change in the recording layer is irradiated with a laser beam having a different intensity or wavelength from that at the time of recording, and a reproduction signal is detected by reflected light or transmitted light.

[0007]

In this optical disk, there is a demand for the protection and management of the disk information by additional information which can be used for copyright protection such as prevention of duplication and unauthorized use of software.

However, in the above configuration, the TOC
Although it is possible to record disc information in the (Control Data) area etc., when disc information is recorded in pre-pits, management is performed for each stamper, and it is not possible to manage disk information for each user. There was a point.

Further, when information is recorded using a magnetic film or a thin film made of a reversible phase change material, it is possible to easily change management information, that is, perform unauthorized rewriting (falsification). However, there is a problem that it is not possible to perform protection management such as copyright of contents in an optical disk.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and has an optical disk provided with additional information that can be used for copyright protection such as prevention of duplication and unauthorized use of software. It is an object of the present invention to provide an information recording method and an information reproducing method, an optical disk reproducing apparatus, an optical disk recording and reproducing apparatus, an optical disk additional information recording apparatus, and an optical disk recording apparatus.

[0011]

In order to achieve the above object, a first structure of an optical disk according to the present invention comprises a recording layer comprising a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface on a disk substrate. An optical disc comprising at least
Additional information formed by a first recording area and a second recording area is provided in a specific portion of the recording layer, and the magnetic anisotropy of the second recording area in the direction perpendicular to the film surface is the film surface of the first recording area. The second recording area is smaller than the magnetic anisotropy in the perpendicular direction, the second recording area is formed as a stripe-shaped mark long in the disk radial direction, and the mark is plurally formed in the disk circumferential direction based on the modulation signal of the additional information. It is characterized by being arranged individually. According to the first configuration of the optical disc, it is possible to realize an optical disc having additional write information that can be used for copyright protection such as prevention of duplication and unauthorized use of software.

In the first configuration of the optical disk of the present invention, it is preferable that the optical disk further comprises an identifier for indicating the presence or absence of a plurality of mark rows arranged in the circumferential direction of the disk. According to this preferred example, it is possible to start up in a short time. In this case, it is preferable that an identifier indicating the presence or absence of the mark string is recorded in the control data. According to this preferred example, at the time when the control data is reproduced, it is known whether or not the additional recording information is recorded, so that the additional recording information can be reliably reproduced.

[0013] In the first configuration of the optical disk of the present invention, it is preferable that the specific portion provided with the additional recording information is an inner peripheral portion of the disk. According to this preferred example, the position of the optical head in the disk radial direction can be measured using the stopper information of the optical head and the address information of the pit signal.

Further, in the first configuration of the optical disk of the present invention, the difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area is equal to or less than a predetermined value. It is particularly preferable that the difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area is 10% or less. According to this preferred example, it is possible to suppress a change in the reproduction waveform due to a change in the amount of reflected light.

Further, in the first configuration of the optical disk of the present invention, it is preferable that a difference between an average refractive index of the first recording area and an average refractive index of the second recording area is 5% or less.
According to this preferred example, the difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area can be set to 10% or less.

Further, in the first configuration of the optical disk of the present invention, it is preferable that the magnetic film in the second recording area is a magnetic film in which in-plane magnetic anisotropy is dominant. According to this preferred example, it is possible to obtain a reproduction signal of the first recording area, which is additional information, using a reader having a polarizer and an analyzer. For this reason, additional information can be quickly detected without using an optical head.

In the first configuration of the optical disk of the present invention, it is preferable that the magnetic film in the second recording area is a magnetic film at least partially crystallized. According to this preferred example, since the magnetic anisotropy of the second recording area in the direction perpendicular to the film surface can be almost eliminated, the reproduction signal can be reliably detected as the difference in the polarization direction from the first recording area. it can.

Further, in the first configuration of the optical disk of the present invention, it is preferable that the recording layer is composed of a plurality of laminated magnetic films. According to this preferred example, since a magnetic super-resolution method called “FAD” can be used as a reproduction method, it is possible to reproduce a signal in an area smaller than a laser beam spot.

A second configuration of the optical disk according to the present invention is an optical disk having at least a recording layer made of a thin film that can reversibly change between two optically detectable states on a disk substrate. Wherein additional information formed by a first recording area and a second recording area is provided in a specific portion of the recording layer, and an amount of reflected light from the first recording area and an amount of reflected light from the second recording area are provided. Wherein the second recording area is formed as a stripe-shaped mark long in the radial direction of the disk, and a plurality of the marks are arranged in the circumferential direction of the disk based on a modulation signal of the additional information. And According to the second configuration of the optical disk, it is possible to realize an optical disk having additional information that can be used for copyright protection such as prevention of duplication and unauthorized use of software.

Further, in the second configuration of the optical disk of the present invention, it is preferable that the optical disk further includes an identifier for indicating the presence or absence of a plurality of mark rows arranged in the circumferential direction of the disk. In this case, it is preferable that an identifier indicating the presence or absence of the mark string is recorded in the control data.

Further, in the second configuration of the optical disk of the present invention, it is preferable that the specific portion having the additional recording information is an inner peripheral portion of the disk. Further, in the second configuration of the optical disc of the present invention, it is preferable that the recording layer reversibly changes its phase between a crystalline phase and an amorphous phase in accordance with the irradiation condition of the irradiated light. According to this preferred example, information can be recorded by utilizing a difference in optical properties based on a reversible structural change at the atomic level between the crystalline phase and the amorphous phase, and a specific information can be recorded. Information can be reproduced as a difference between the reflected light amount or the transmitted light amount with respect to the wavelength. In this case, it is preferable that the difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area is 10% or more. According to this preferred example, a reproduction signal of the first recording area, which is additional recording information, can be reliably obtained. In this case, the difference between the average refractive index of the first recording area and the average refractive index of the second recording area is preferably 5% or more. According to this preferred example, the difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area can be set to 10% or more. Further, in this case, it is preferable that the second recording region of the recording layer is a crystalline phase. According to this preferred example, recording can be performed with an excessive laser power. Also, since the amount of reflected light of the crystal phase can be increased,
Reproduction signal detection becomes easy. In this case, it is preferable that the recording layer is made of a Ge—Sb—Te alloy.

In a third configuration of the optical disk according to the present invention, the main information is recorded, additional write information different for each disk is recorded, and at least a watermark is created in the additional information. It is characterized in that a watermark creation parameter is recorded.
According to the third configuration of the optical disc, the following effects can be obtained. In other words, with the correlation between the disc ID and the watermark creation parameter completely eliminated, the watermark creation parameter and the disc I
If D is recorded in the write-once information, the watermark cannot be inferred from the disc ID by calculation. For this reason, it is possible to prevent an unauthorized copy company from issuing a new ID and illegally issuing a watermark.

In the third configuration of the optical disk of the present invention, the main information is recorded by providing the concave and convex bits on the reflective film, and the additional information is recorded by partially removing the reflective film. Is preferred.

In the third configuration of the optical disk of the present invention, it is preferable that the main information and the additional information are recorded by partially changing the reflectance of the recording layer.

In the third configuration of the optical disk of the present invention, the main information is obtained by partially changing the direction of magnetization of a recording layer composed of a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface. It is preferable that additional information be recorded by partially changing the film surface perpendicular magnetic anisotropy.

Further, a first method for recording additional information on an optical disk according to the present invention is characterized in that at least a recording layer made of a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface is provided on a disk substrate; A method for recording additional recording information on an optical disk having additional recording information formed by a first recording area and a second recording area in a specific portion of a recording layer, wherein the additional recording is performed in a disk circumferential direction of the specific portion of the recording layer. By irradiating a laser beam based on the information modulation signal, the magnetic anisotropy of the second recording area in the direction perpendicular to the film surface becomes smaller than the magnetic anisotropy of the first recording area in the direction perpendicular to the film surface. Thus, a plurality of the second recording areas are formed in the circumferential direction of the disk as stripe-shaped marks long in the radial direction of the disk. According to the first recording method of the additional information on the optical disk, the additional information that can be used for copyright protection such as prevention of duplication and unauthorized use of software can be efficiently recorded on the optical disk.

In the first recording method of the additional information according to the present invention, when the second recording area is formed, the laser light source is caused to emit a pulse light based on a phase-encoded modulation signal of the additional information. Preferably, the optical disk or the laser beam is rotated. According to this preferred example, the rotation unevenness can be eliminated particularly by using the clock of the rotation sensor, and it is possible to record additional recording information with a small fluctuation of the channel clock cycle.

Further, in the first recording method of the postscript information according to the present invention, a reflective layer and a protective layer are further provided on the disk substrate, and the intensity of the laser beam irradiated to form the second recording area is reduced. It is preferable that the intensity is smaller than the intensity of the laser beam that destroys at least one of the disk substrate, the reflective layer, and the protective layer. According to this preferred example, it is possible to record additional information at a software company or a store.

In the first recording method of the additional information according to the present invention, the intensity of the laser beam applied to form the second recording area is an intensity for crystallizing at least a part of the recording layer. Is preferred. According to this preferred example, since the magnetic anisotropy of the recording layer in the direction perpendicular to the film surface cannot be restored, it is possible to prevent falsification of the additional information.

In the first recording method of the additional information according to the present invention, the intensity of the laser light irradiated to form the second recording area is higher than the intensity of the laser light at which the recording layer reaches the Curie temperature. Is also preferably large. According to this preferred example, the magnetic anisotropy of the recording layer in the direction perpendicular to the film surface can be reduced or eliminated, particularly when the intensity of the laser beam is excessive.

Further, in the first recording method of the additional recording information according to the present invention, the intensity of the laser beam irradiated for forming the second recording area is such that the magnetic film in the first recording area has an in-plane direction. The strength is preferably such that the magnetic anisotropy changes into a dominant magnetic film.

Further, in the first recording method of the postscript information according to the present invention, when forming the second recording area, the recording layer is irradiated with a rectangular stripe-shaped laser beam using a one-way converging lens. Is preferred.

In the first recording method of the postscript information according to the present invention, it is preferable that a light source of a laser beam irradiated to form the second recording area is a YAG laser. In this case, it is preferable to apply a magnetic field of a predetermined value or more to the recording layer when irradiating the YAG laser with laser light. According to this preferred example, after the magnetization direction of the recording layer is aligned in one direction perpendicular to the film surface, the additional information can be easily recorded by partially changing the film surface perpendicular magnetic anisotropy. Can be. In this case, it is preferable that the magnetic field applied to the recording layer is 5 kOe or more.

According to a second method of recording additional information on an optical disk according to the present invention, a recording layer composed of a thin film capable of reversibly changing between two optically detectable states is formed on a disk substrate. A method for recording additional recording information of an optical disc, comprising at least a recording section and additional recording information formed by a first recording area and a second recording area in a specific section of the recording layer, wherein the disc of the specific section of the recording layer is provided. By irradiating a laser beam in the circumferential direction based on the modulation signal of the additional recording information, the second recording area is changed so that the amount of reflected light from the first recording area and the amount of reflected light from the second recording area are different. A plurality of regions are formed in the disk circumferential direction as stripe-shaped marks that are long in the disk radial direction. According to the second recording method of the additional information on the optical disk, the additional information that can be used for copyright protection such as prevention of duplication and unauthorized use of software can be efficiently recorded on the optical disk.

Further, in the second recording method of the additional information according to the present invention, when forming the second recording area, the laser light source is caused to emit a pulse light based on a modulation signal of the additional information which is phase-encoded. Preferably, the optical disk or the laser beam is rotated.

[0036] In the second recording method of the postscript information according to the present invention, a reflective layer and a protective layer are further provided on the disk substrate, and the intensity of the laser light irradiated to form the second recording area is reduced. It is preferable that the intensity is smaller than the intensity of the laser beam that destroys at least one of the disk substrate, the reflective layer, and the protective layer.

In the second recording method of the postscript information according to the present invention, the intensity of the laser light applied to form the second recording area is an intensity for crystallizing at least a part of the recording layer. Is preferred.

Further, in the second recording method of the postscript information according to the present invention, when forming the second recording area, the recording layer is irradiated with a rectangular stripe-shaped laser beam using a one-way converging lens. Is preferred. Further, in this case, it is preferable that the light source of the laser beam irradiated to form the second recording area is a YAG laser. Further, a third recording method of the additional recording information of the optical disk according to the present invention is characterized in that a watermark is created based on the disk ID, and the watermark is superimposed on specific data and recorded as additional recording information. According to the third recording method of the additional recording information of the optical disk, the disk ID of the watermark can be detected from the additional recording information, and the source of the illegal copy can be clarified.

Further, a first reproducing method of additional information of an optical disk according to the present invention is characterized in that at least a recording layer made of a magnetic film having magnetic anisotropy in a direction perpendicular to a film surface is provided on a disk substrate; A method of reproducing additional information on an optical disc having additional information formed by a first recording area and a second recording area having different magnetic anisotropies in a direction perpendicular to a film surface in a specific portion of a recording layer, comprising: The write-once information is reproduced by inputting a linearly polarized laser beam to the optical disk and detecting a change in rotation of a polarization direction of reflected light or transmitted light from the optical disk. According to the first reproduction method of the additional information on the optical disk, the additional information can be easily reproduced.

Further, in the first method of reproducing the additional information according to the present invention, after a magnetic field larger than the coercive force of the recording layer is applied to the specific portion, the recording layer of the specific portion is collectively magnetized. It is preferable that a linearly polarized laser beam is incident on the specific portion. According to this preferred example, the first
The magnitude of rotation in the polarization direction detected from the recording area is always constant, and a reproduced signal due to the difference in rotation in the polarization direction from the second recording area is obtained as a stable amplitude.

Further, in the first method for reproducing additional information according to the present invention, the specific portion is irradiated with a certain amount of laser light to raise the temperature of the recording layer of the specific portion to a Curie temperature or higher. It is preferable that, after applying a magnetic field in one direction to the specific portion so that the direction of magnetization of the recording layer of the specific portion is aligned in one direction, linearly polarized laser light is incident on the specific portion. According to this preferred example, after recording the additional recording information, it is possible to stably reproduce the signal without being affected by an external magnetic field or the like.

Further, in the second reproducing method of the write-once information of the optical disk according to the present invention, a recording layer made of a thin film capable of reversibly changing between two optically detectable states is formed on a disk substrate. A method for reproducing additional information of an optical disc including at least additional information and additional information formed by a first recording area and a second recording area having different reflectances in a specific portion of the recording layer, The additional recording information is reproduced by irradiating the collected laser light and detecting a change in the amount of reflected light. According to the second reproduction method of the additional information on the optical disk, the additional information can be easily reproduced.

In a first configuration of the optical disk reproducing apparatus according to the present invention, a main information recording area in which a signal of main information is recorded and a part of the main information recording area are provided so as to overlap. A sub-signal recording area in which a phase-encoded modulated sub-signal is superimposed on the main information signal and recorded, wherein the optical disc is subjected to rotational phase control, and Means for reproducing the main information signal in the main information recording area, first demodulation means for demodulating the main information signal to obtain main information data, and signal for the main information in the sub signal recording area Means for reproducing a mixed signal obtained by mixing the signal and the sub signal as a reproduction signal by the optical head; frequency separation means for suppressing the main information signal in the reproduction signal to obtain the sub signal; Faith The by phase encode demodulated, characterized in that a second demodulating means for obtaining the sub-data. According to the first configuration of the optical disk reproducing apparatus,
The demodulated data of the sub signal can be reliably reproduced.

In the first configuration of the optical disk reproducing apparatus of the present invention, the frequency separating means suppresses the high frequency component of the reproduced signal reproduced by the optical head to obtain a low frequency reproduced signal. A second slice level setting unit for generating a second slice level from the low frequency reproduction signal, and a second signal obtained by slicing the low frequency reproduction signal at the second slice level. Preferably, a second level slicer is provided, and the binary signal is phase-encoded and demodulated to obtain sub data. According to this preferred example, it is possible to prevent an error due to a change in the envelope of the reproduction signal of the additional recording information. In this case, the second slice level setting unit is provided with a sub-low frequency component separating unit having a time constant larger than that of the low frequency component separating unit. It is preferable to input the reproduced signal or the low-frequency reproduced signal obtained by the low-frequency component separating means, extract a component having a lower frequency than the low-frequency reproduced signal, and obtain the second slice level. According to this preferred example, a slice level that follows the level fluctuation of the low-frequency component can be set, so that the signal can be easily reproduced.

In the first configuration of the optical disk reproducing apparatus of the present invention, the signal of the main information in the reproduction signal reproduced by the optical head is converted from a time axis signal to a frequency axis signal to perform the first conversion. Frequency conversion means for generating a signal, means for generating a mixed signal obtained by adding or superimposing sub-information on the first converted signal, and converting the mixed signal from a frequency axis signal to a time axis signal to generate a second converted signal. It is preferable that the apparatus further includes an inverse frequency conversion unit to be created. According to this preferred example, since the ID signal can be spread spectrum, deterioration of the video signal of the main information can be prevented, and the reproduction of the main information becomes easy.

In a second configuration of the optical disk reproducing apparatus according to the present invention, linearly polarized light is made incident on the optical disk using an optical head, and transmitted light or reflected light from the optical disk is recorded on the optical disk. An optical disc reproducing device that detects a change in rotation of a polarization direction in response to a signal, wherein, if necessary, a unit that moves the optical head to a specific portion of the optical disc on which additional recording information is recorded; and Means for detecting the transmitted light or reflected light as a change in the rotation of the polarization direction and reproducing the postscript information. The second of this optical disc reproducing device
According to the configuration described above, since the influence of the fluctuation of the reflected light amount and the influence of the noise component included as the addition signal are not affected, the detection of the reproduction signal is facilitated.

Further, in the second configuration of the optical disk reproducing apparatus of the present invention, the detection signal from the detection light received by at least one light receiving element of the optical head or the detection light received by the plurality of light receiving elements Means for detecting an identifier indicating the presence or absence of the additional information from the control data based on the sum signal of the detection signals from the
It is preferable that, when the identifier is detected and the presence of the additional information is confirmed, the optical head is moved to a specific portion of the optical disk on which the additional information is recorded as necessary. According to this preferred example, it is possible to easily determine the stripe and the defect of the additional information, so that the rise time of the apparatus can be shortened.

In the second structure of the optical disk reproducing apparatus of the present invention, it is preferable that the optical disk reproducing apparatus further comprises a demodulation means for performing phase encoding demodulation when reproducing the additional recording information. According to this preferred example, it can be used for reproducing additional information such as an ID signal.

A third configuration of the optical disk reproducing apparatus according to the present invention is an optical disk reproducing apparatus in which main information is recorded and additional write information different for each disk is recorded. A signal reproducing unit that reproduces information, a postscript information reproducing unit that reproduces the postscript information, and a watermark adding unit that creates a watermark signal based on the postscript information and outputs it in addition to the main information. It is characterized by the following. According to the third configuration of the optical disk reproducing apparatus, it is possible to prevent illegal copying to extract main information such as a video signal.

In the third configuration of the optical disk reproducing apparatus according to the present invention, it is preferable that the write-once information is recorded by partially changing a reflectance of a recording layer of the optical disk.

In the third configuration of the optical disk reproducing apparatus according to the present invention, the recording layer of the optical disk is made of a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the write-once information is recorded in the perpendicular magnetic film. It is preferably recorded by partially changing the anisotropy.

In the third configuration of the optical disk reproducing apparatus of the present invention, it is preferable that the sub-information including the watermark is superimposed on the signal of the main information by the watermark adding section. According to this preferred example, it is possible to prevent a normal recording / reproducing system from reproducing the main information by removing the sub-information from the main information.

Further, in the third configuration of the optical disk reproducing apparatus of the present invention, a frequency conversion means for converting a signal of main information from a time axis signal to a frequency axis signal to generate a first conversion signal; Means for creating a mixed signal in which additional information is added or superimposed on the first converted signal; and inverse frequency converting means for converting the mixed signal from a frequency axis signal to a time axis signal to generate a second converted signal. Is preferred.

In the third structure of the optical disk reproducing apparatus of the present invention, the apparatus further comprises an MPEG decoder for expanding main information into a video signal, and means for inputting the video signal to a watermark adding unit. Is preferred. According to this preferred example, it is possible to spread the watermark and add the watermark without deteriorating main information such as a video signal. In this case, a watermark reproducing unit for reproducing the watermark is further provided, and a mutual authentication unit is provided in both the MPEG decoder and the watermark reproducing unit to transmit the encrypted main information, It is preferable that the decryption be performed only when mutual authentication is performed. According to this preferred example, even if a digital signal is extracted from a bus on the way, the encryption is not decrypted, so that unauthorized removal and tampering of the watermark can be prevented. Also, in this case,
The composite signal obtained by combining the main information with the encryption decoder is MP
Preferably, it is input to the EG decoder. According to this preferred example, by eliminating the correlation between the information such as the ID and the watermark creation parameter, it is possible to prevent the illegal copying due to the issuance of a new illegal watermark such as the ID. In this case, a watermark reproducing unit for reproducing the watermark is further provided, and a mutual authentication unit is provided in both the encryption decoder and the watermark reproducing unit, and transmits the encrypted main information. It is preferable that the decryption be performed only when authentication is performed.

The first configuration of the optical disk recording / reproducing apparatus according to the present invention comprises a main circuit using a recording circuit and an optical head in a main recording area of a recording layer of an optical disk capable of recording, erasing and reproducing information. An optical disk recording / reproducing apparatus for recording information, wherein the additional information recorded in the specific portion of the recording layer is reproduced by a signal output unit of the optical head which detects a change in rotation of a polarization plane, and Means for recording the main information in the main recording area as encryption information encrypted by an encryption encoder using additional information,
Means for reproducing the additional information by a signal output section of the optical head, and a means for reproducing the main information by decrypting the encrypted information as a decryption key in an encryption decoder. The first of the optical disk recording and reproducing devices
According to the configuration, unauthorized copying can be prevented, so that copyright can be protected.

A second configuration of the optical disk recording / reproducing apparatus according to the present invention is an optical disk recording / reproducing apparatus for recording main information in a main recording area of a recording layer of the optical disk by using a recording circuit and an optical head. There is provided a watermark adding unit for adding a watermark to the main information,
The additional recording information recorded in the specific portion of the recording layer is reproduced by the optical head, and the reproduced additional recording information is added to the main information as a watermark by the watermark adding unit, and the watermarked main information is added. Is recorded in the main recording area. According to the second configuration of the optical disk recording / reproducing apparatus, since the recording history can be traced from the recorded data of the watermark, it is possible to prevent illegal copying and unauthorized use.

In the second configuration of the optical disk recording / reproducing apparatus of the present invention, it is preferable that the main information is recorded by partially changing the reflectance of the recording layer.

Further, in the second configuration of the optical disk recording / reproducing apparatus of the present invention, the recording layer is made of a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the main information is the magnetization of the magnetic film. It is preferably recorded by partially changing the direction. In this case, the main information and the additional information are detected by the optical head detecting a change in the direction of magnetization of the recording layer or a change in the magnitude of the perpendicular magnetic anisotropy of the recording layer as a change in the rotation of the polarization plane. It is preferably reproduced.

In the second configuration of the optical disk recording / reproducing apparatus according to the present invention, it is preferable that the sub-information including the watermark is superimposed on the signal of the main information by the watermark adding section.

Further, in the second configuration of the optical disk recording / reproducing apparatus of the present invention, frequency conversion means for converting a signal of main information from a time axis signal to a frequency axis signal to generate a first conversion signal; Means for creating a mixed signal in which additional information is added or superimposed on the first converted signal; and inverse frequency converting means for converting the mixed signal from a frequency axis signal to a time axis signal to generate a second converted signal. Preferably it is provided.

Further, in the second configuration of the optical disk recording / reproducing apparatus of the present invention, the optical disk recording / reproducing apparatus further comprises an MPEG decoder for expanding main information into a video signal, and means for inputting the video signal to a watermark adding unit. Is preferred. In this case, a watermark reproducing unit for reproducing the watermark is further provided, and
A mutual authentication unit is provided in both the PEG decoder and the watermark reproducing unit, and transmits the encrypted main information,
It is preferable that the decryption be performed only when mutual authentication is performed. In this case, it is preferable that a composite signal obtained by combining the main information with the encryption decoder is input to the MPEG decoder. In this case, a watermark reproducing unit for reproducing the watermark is further provided, and a mutual authentication unit is provided in both the encryption decoder and the watermark reproducing unit, and transmits the encrypted main information. It is preferable that the decryption be performed only when authentication is performed.

Further, the structure of the recording device for recording additional information on an optical disk according to the present invention is a recording device for recording additional information on an optical disk that records additional information on an optical disk on which main information is recorded. The recording apparatus further comprises means for recording sub-information including at least one of the parameters. According to the configuration of the recording device for the additional information of the optical disk, the user who has illegally copied or used the disk can be identified from the disk ID or the watermark, so that the copyright can be protected.

Further, in the configuration of the recording device for additional information of the optical disk of the present invention, the main information is recorded by providing concave and convex pits on the reflection film of the optical disk, and the sub-information is partially recorded on the reflection film. It is preferably recorded by removal.

Further, in the configuration of the recording device of the additional recording information of the optical disk of the present invention, the main information is recorded by partially changing the reflectance of the recording layer of the optical disk, and the sub information is recorded by the recording layer. Is preferably recorded by partially changing the reflectance.

Further, in the configuration of the recording device for additional information of the optical disk of the present invention, the recording layer of the optical disk is made of a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the main information is the magnetization of the magnetic film. And it is preferable that the sub-information is recorded by partially changing the perpendicular magnetic anisotropy of the film surface.

The recording apparatus for an optical disk according to the present invention is a recording apparatus for an optical disk on which main information is recorded, wherein a means for creating a watermark based on sub-information including a disk ID; Means for recording data in which a mark is superimposed on specific data. According to the configuration of the recording apparatus for the optical disc, the watermark can be detected from the recorded data, and the history of the content can be clarified, so that the copyright can be protected.

[0067]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to embodiments. <First Embodiment> First, the structure of a magneto-optical disk will be described.

FIG. 1 is a sectional view showing the structure of a magneto-optical disk according to the first embodiment of the present invention. As shown in FIG. 1, a dielectric layer 212
The recording layer 213 is formed via the. Recording layer 213
Includes a BCA (one method of write-once identification information) unit 22
0a and 220b are recorded in the circumferential direction of the disk. An intermediate dielectric layer 214 and a reflective layer 215 are sequentially laminated on the recording layer 213, and an overcoat layer 216 is further formed thereon.

Next, a method for manufacturing a magneto-optical disk according to the present embodiment will be described with reference to FIG.
First, as shown in FIG. 8A, a disk substrate 211 on which guide grooves or prepits for tracking guide are formed by an injection molding method using a polycarbonate resin. Next, as shown in FIG. 8B, an 80 nm-thick dielectric of SiN film is formed on the disk substrate 211 by subjecting the Si target to reactive sputtering in an atmosphere containing Ar gas and nitrogen gas. A layer 212 is formed. Next, as shown in FIG. 8 (3), DC sputtering is performed on a TbFeCo alloy target in an Ar gas atmosphere to thereby form the dielectric layer 2.
A recording layer 213 having a thickness of 30 nm made of a TbFeCo film is formed on the recording layer 213. Next, as shown in FIG. 8D, a reactive sputtering is performed on the Si target in an atmosphere containing Ar gas and nitrogen gas, so that the recording layer 2 is formed.
On the substrate 13, an intermediate dielectric layer 214 having a thickness of 20 nm and made of a SiN film is formed. Next, as shown in FIG. 8 (5), a 40 nm-thick reflective layer 215 made of an AlTi film is formed on the intermediate dielectric layer 214 by subjecting the AlTi target to DC sputtering in an Ar gas atmosphere. . Finally, as shown in FIG.
After the ultraviolet curable resin is dropped on the reflective layer 215, the ultraviolet curable resin is applied by a spin coater at a rotation speed of 2500 rpm, and the ultraviolet curable resin is cured by irradiating ultraviolet rays. 10μ thickness
The m overcoat layer 216 is formed.

Next, a method for recording identification information (additional information) will be described with reference to FIG. First, FIG.
As shown in (7), the recording layer 21 is
The magnetization directions of No. 3 are aligned in one direction. Since the recording layer 213 of the magneto-optical disk of the present embodiment is a perpendicular magnetization film having a coercive force of 11 kilooersted, the intensity of the magnetic field of the electromagnet of the magnetizer 217 is set to 15 kilogauss. Is passed through the magneto-optical disk, whereby the direction of magnetization of the recording layer 213 can be aligned with the direction of the magnetic field of the magnetizer 217. Next, as shown in FIG. 9 (8), using a high-power laser 218 such as a YAG laser and a one-way converging lens 219 such as a cylindrical lens,
The laser light having a rectangular stripe shape is converged on the recording layer 213, and the BCA portions 220a and 22
0b are recorded in the disk circumferential direction. The recording principle, recording method, and reproduction method will be described later in detail. Next, as shown in FIG.
21 to detect the BCA units 220a and 220b,
E (phase encoding) demodulation is performed and compared with the recorded data to check whether the data is correct. If the data coincides with the recording data, the recording of the identification information is completed, and if not, the magneto-optical disk is removed from the process.

Next, the principle of the BCA reader 221 will be described with reference to FIG. FIG. 10 (a),
As shown in (c), the polarizer 22 of the BCA reader 221
The polarization planes of the analyzer 2 and the analyzer 223 are orthogonal to each other. Therefore, as shown in FIGS. 10A and 10B, even if the light beam is applied to the BCA portion 220a of the recording layer 213, the BC
Since the perpendicular magnetic anisotropy of the A portion 220a is low (the magnetic anisotropy in the in-plane direction is dominant), no detection signal is output. However, when the light beam is applied to a portion other than the BCA portion (non-BCA portion 224) of the recording layer 213, the portion is magnetized in one direction perpendicular to the film surface, so that the polarization of the reflected light is Surface rotates, PD (photo detector) 25
The signal is output to 6. As described above, FIG.
A BCA reproduction signal as shown in (b) is obtained, and the BCA section 220 can be detected quickly without using an optical head for magneto-optical recording and reproduction.

In this case, the BCA portion 220a has a significantly reduced magnetic anisotropy in a direction perpendicular to the film surface.
A reproduction signal is obtained. Hereinafter, this will be described. FIG. 4 shows the identification information of the recording layer 213, that is, the hysteresis loop 225a of the BCA portion 220 that has been heat-treated by irradiation with laser light, and the non-BCA that has not been heat-treated.
The Kerr hysteresis loop 225b in a direction perpendicular to the film surface of the portion 224 is shown. As shown in FIG. 4, it can be seen that the Kerr rotation angle and the perpendicular magnetic anisotropy of the heat-treated BCA portion 220 are significantly deteriorated. As described above, in the BCA portion 220 that has been subjected to the heat treatment, the residual magnetism in the perpendicular direction is lost, so that the magneto-optical recording cannot be performed.

In this embodiment, as shown in FIG. 9, after the direction of magnetization of the perpendicular magnetization film of the recording layer 213 is aligned in one direction (after magnetization), BC as identification information is obtained.
A section 220 is recorded, but the respective layers are stacked and the recording layer 2
After recording the BCA portion 220 by deteriorating the recording layer 13, the temperature of the recording layer 213 is increased by irradiating a strobe light or the like, thereby applying a magnetic field smaller than the magnetic field when magnetized at room temperature. It is also possible to make the direction of magnetization of the perpendicular magnetization film 213 uniform in one direction.

The recording layer 213 of the magneto-optical disk according to the present embodiment has a coercive force of 11 kOe at room temperature.
When the temperature is raised to not less than ° C., the coercive force becomes 4 kOe or less, so that by applying a magnetic field of 5 kOe or more, the magnetization direction of the recording layer 213 can be aligned in one direction.

Next, the recording power of magneto-optical BCA recording will be described. FIG. 5 shows B manufactured by Matsushita Electric Industrial Co., Ltd.
CA trimming device "BCA recording device (YAG laser 5
BW recording characteristics when a BCA signal is recorded from the light input surface side of a magneto-optical disk using “0 W ramp excitation CWQ pulse recording”. As shown in FIG. 5, when the recording current of the laser is 8 A or less, the BCA portion is not recorded. When the recording current of the laser is 8 to 9 A, which is the optimum recording current, a BCA image 226a can be obtained only with a polarizing microscope, as shown in FIGS. This BCA image 2
26a is not visible with an optical microscope. When the recording current of the laser is 9 A or more, as shown in FIG. 5 and FIG.
b, 226c are obtained. When the recording current of the laser shown in FIG. 5 is 10 A or more, the protective layer (overcoat layer)
Has been destroyed. This state is shown in FIG. As shown in FIG. 11A, the reflection layer 215 and the overcoat layer 216 are destroyed by the application of excessive laser power. On the other hand, the recording current of the laser is 8 which is the optimum recording current.
11A, only the recording layer 213 is deteriorated, and neither the reflection layer 215 nor the overcoat layer 216 is destroyed, as shown in FIG. 11B.

Next, a recording / reproducing apparatus for a magneto-optical disk according to the present embodiment will be described with reference to FIG. FIG. 7 is a diagram showing an optical configuration of a magneto-optical disk recording / reproducing apparatus according to the first embodiment of the present invention. In FIG. 7, reference numeral 255 denotes an optical head of a magneto-optical disk;
4 is a pulse generator, 241 is a laser light source, 242 is a collimating lens, 243 is a polarization beam splitter, 244
Is an objective lens for condensing the laser beam on the magneto-optical disk, 246 is a half mirror that separates reflected light from the magneto-optical disk into a signal reproducing direction and a focus tracking control direction, and 247 is a magneto-optical disk. Λ plate 248 for rotating the polarization plane of the reflected light, 248 is a polarizing beam splitter for separating reflected light from the magneto-optical disk according to the polarization direction, 249 and 250 are light receiving elements, and 253 is a light receiving unit for focus tracking. Department. Reference numeral 240 denotes a magneto-optical disk according to the embodiment, reference numeral 251 denotes a magnetic head, and reference numeral 252 denotes a magnetic head drive circuit.

As shown in FIG. 7, the linearly polarized laser beam emitted from the laser light source 241 is converted by the collimating lens 242 to be a parallel laser beam. As for this laser beam, only the P-polarized light passes through the polarization beam splitter 243, is condensed by the objective lens 244, and is irradiated on the recording layer of the magneto-optical disk 240. At this time, the information (data information) of the normal recording data is recorded by partially changing the magnetization direction (upward and downward) of the perpendicular magnetization film, and the reflected light from the magneto-optical disk 240 (or The transmitted light changes as the rotation of the polarization plane according to the magnetization state due to the magneto-optical effect. The reflected light whose polarization plane has been rotated as described above is reflected by the polarization beam splitter 243, and then separated by the half mirror 246 into a signal reproduction direction and a focus / tracking control direction.
The light separated in the signal reproduction direction is rotated by 45 ° by the λ / 4 plate 247 in the polarization beam splitter 2.
48 separates the traveling directions into the P-polarized light component and the S-polarized light component. The light separated in two directions is a light receiving element 2
The light amounts are detected by 49 and 250, respectively. The change in the rotation of the polarization plane is caused by the two light receiving elements 2
The signal is detected as a differential signal of the amount of light detected by 49 and 250, and a reproduced signal of data information is obtained by the differential signal. The light in the focus / tracking control direction separated by the half mirror 246 is transmitted to the objective lens 2 by the focus / tracking control unit 253.
44 are used for focus control and tracking control.

The BCA section 220 as the identification information of the magneto-optical disk according to the present embodiment is detected by using the same method as the data information reproducing method. As shown in FIG. 4, the BCA portion 220 that has been subjected to the heat treatment has significantly deteriorated perpendicular magnetic anisotropy (hysteresis loop 225a). Since the direction of magnetization of the perpendicular magnetization film is aligned in one direction when the recording layer is manufactured or when a signal is reproduced, the laser beam incident on the non-heat-treated non-BCA portion 224 having a large perpendicular magnetic anisotropy is polarized. The surface is reflected after being rotated by θ _{k in} one direction in accordance with the direction of magnetization. On the other hand, the BCA portion 22 which has been subjected to the heat treatment and the perpendicular magnetic anisotropy has significantly deteriorated.
At 0, the car rotation angle is very small, so B
The laser beam incident on the CA unit 220 is reflected with its polarization plane hardly rotated.

Here, there are the following methods for aligning the magnetization directions of the perpendicular magnetization film in one direction during reproduction of the BCA portion. That is, in the magneto-optical disk recording / reproducing apparatus of FIG.
The magnetic head 251 irradiates a laser beam of 4 mW or more so that 3 is at or above the Curie temperature.
A constant magnetic field equal to or more than Oersted is applied to the magneto-optical disk 240.
, The magnetization direction of the recording layer of the BCA portion can be aligned in one direction.

FIG. 6A shows a trace of a waveform photograph of a differential signal for which identification information is actually detected.
(B) shows a traced waveform photograph of the addition signal from which the identification information is actually detected. As shown in FIG.
It can be seen that a pulse waveform of identification information having a sufficient amplitude ratio is detected in the differential signal. At this time, the recording layer changes only in the magnetic characteristics. Even when a part of the recording layer is crystallized, the change in the average refractive index is 5% or less. The variation is less than 10%. Therefore, the fluctuation of the reproduction waveform due to the change in the amount of reflected light is very small.

FIG. 13 shows the polarization state of the reflected light with respect to the incident light. As shown in FIG. 13B, the BCA portion 220 that has been subjected to the heat treatment has the same polarization direction 22 as the incident light.
7b is reflected. On the other hand, FIG.
As shown in (2), in the non-BCA portion 224 that has not been heat-treated, the Kerr effect of the magnetic film having perpendicular magnetic anisotropy causes
Light in the polarization direction 227a having a rotation angle θ _k with respect to the incident light is reflected.

Further, in this embodiment, the identification information is detected by the differential signal. However, if this reproducing method is used, the light quantity fluctuation component without polarization can be almost canceled. This is effective in reducing noise due to

<Second Embodiment> FIG. 2 shows a second embodiment of the present invention.
FIG. 3 is a cross-sectional view illustrating a configuration of a magneto-optical disk according to the embodiment. As shown in FIG. 2, a recording layer having a three-layer structure including a reproducing magnetic film 233, an intermediate magnetic film 234, and a recording magnetic film 235 is formed on a disk substrate 231 via a dielectric layer 232. The recording layer has a BCA section 220
a and 220b are recorded in the circumferential direction of the disk. On the recording layer, the intermediate dielectric layer 236 and the reflection layer 23
7 are sequentially laminated, and an overcoat layer 238 is further formed thereon.

Next, a method for manufacturing a magneto-optical disk according to the present embodiment will be described with reference to FIGS. 8 and 9 used in the first embodiment. First, a disk substrate 231 on which guide grooves or prepits for tracking guide are formed by an injection molding method using a polycarbonate resin. Next, an 80 nm-thick dielectric layer 232 made of a SiN film is formed on the disk substrate 231 by performing reactive sputtering on the Si target in an atmosphere containing Ar gas and nitrogen gas. The recording layer includes a reproducing magnetic film 233 made of a GdFeCo film having a Curie temperature T _c1 and a coercive force H _c1 , an intermediate magnetic film 234 made of a TbFe film having a Curie temperature T _c2 and a coercive force H _c2 , and a Curie temperature T _c3. is constituted by the recording magnetic film 235 made of TbFeCo film is a coercive force H _c3, by performing DC sputtering to the respective alloy targets in an Ar gas atmosphere, on the dielectric layer 232, successively each layer Laminate. Next, by subjecting the Si target to reactive sputtering in an atmosphere containing Ar gas and nitrogen gas,
An intermediate dielectric layer 236 having a thickness of 20 nm made of an N film is formed. Next, the AlTi target is subjected to DC sputtering in an Ar gas atmosphere to form a 40 nm-thick reflective layer 237 made of an AlTi film on the intermediate dielectric layer 236. Finally, after the ultraviolet curable resin is dropped on the reflective layer 237, the resin is applied with a spin coater.
The UV curable resin is applied at a rotation speed of 00 rpm, and the UV curable resin is cured by irradiating ultraviolet rays, thereby forming an 8 μm thick overcoat layer 238 on the reflective layer 237.

The reproducing magnetic film 233 has a thickness of 40.
nm, Curie temperature T _c1 is 300 ° C., coercive force H at room temperature
_c1 is set to 100 Oersted respectively. The intermediate magnetic film 234 has a thickness of 10 nm, a Curie temperature T _c2 of 120 ° C., and a coercive force H _c2 at room temperature of 3 kOe. The recording magnetic film 2
35 has a film thickness of 50 nm and a Curie temperature T _c3 of 230
The coercive force H _c3 at 15 ° C. and room temperature is set to 15 kOe.

Next, the principle of reproduction in the recording layer having a three-layer structure according to the present embodiment will be described with reference to FIG. In FIG. 3, 228 is a reproducing magnetic field, 229a, 229b,
229c is a laser beam spot, 230 is a recording domain,
233 is a reproducing magnetic film, 234 is an intermediate magnetic film, and 235 is a recording magnetic film. As shown in FIG. 3, the recording domain 230 of the information signal is recorded on the recording magnetic film 235, and at room temperature, the recording magnetic film 235, the intermediate magnetic film 234, and the reproducing magnetic film 233 cause an exchange coupling force to cause the recording magnetic film 235 to change. The magnetization of the film 235 is transferred to the reproducing magnetic film 233. At the time of signal reproduction, the low-temperature portion 229b of the laser light spot 229a keeps the signal of the recording magnetic film 235 transferred to the reproduction magnetic film 233, but the high-temperature portion 229b of the laser light spot 229a.
In (c), since the Curie temperature of the intermediate magnetic film 234 is lower than the Curie temperature of the other magnetic films, the exchange coupling force between the recording magnetic film 235 and the reproducing magnetic film 233 is cut off. As a result, the direction of magnetization of the reproducing magnetic film 233 is aligned with the direction of the reproducing magnetic field 228. For this reason, the recording domain 230 of the information signal is in a state where the high temperature part 229c which is a part of the laser beam spot 229a is masked.
Therefore, it is possible to reproduce a signal only from the low temperature part 229b of the laser beam spot 229a. This reproduction method is called "F
AD ", and by using this reproducing method, it is possible to reproduce a signal in an area smaller than the laser beam spot.

The same reproduction is possible even when a magnetic super-resolution method called "RAD" capable of reproducing a signal only from a high-temperature portion of a laser beam spot is used. Next, a method of recording identification information (additional information) on the magneto-optical disk of the present embodiment will be described with reference to FIG.

First, as shown in FIG.
17, the direction of magnetization of the recording layer is aligned in one direction. Recording magnetic film 23 of recording layer of magneto-optical disk of the present embodiment
Reference numeral 5 denotes a perpendicular magnetization film having a coercive force of 15 kOe, so that the strength of the magnetic field of the electromagnet of the magnetizer 217 is 2
By setting the magnetic field to 0 kilogauss and passing the magnetic field through the magneto-optical disk, the direction of magnetization of the recording layer can be aligned with the direction of the magnetic field of the magnetizer 217. Then
As shown in FIG. 9 (8), using a high-power laser 218 such as a YAG laser and a one-way converging lens 219 such as a cylindrical lens, a rectangular stripe-shaped laser beam is converged on the recording layer, and Parts 220a, 220
b is recorded in plural numbers in the circumferential direction of the disk. The recording principle, recording method, and reproduction method are the same as those in the first embodiment. Further, similarly to the first embodiment, the magnetization of the recording layer may be performed after recording the BCA. further,
When the recording layer is heated and magnetized by using strobe light or the like, the magnetization direction of the recording layer is changed in one direction even if the magnetic field is 5 kOe, which is smaller than the case where the recording layer is magnetized at room temperature. Can be aligned.

The recording layer in the present embodiment has a three-layer structure including the reproducing magnetic film 233, the intermediate magnetic film 234, and the recording magnetic film 235. At least the heat treatment of the recording magnetic film 235 is performed on the film surface. The identification information can be recorded by remarkably reducing the magnetic anisotropy in the perpendicular direction and making the magnetic anisotropy in the substantially in-plane direction dominant.

Here, the Curie temperature and coercive force of the magnetic film constituting the recording layer can be relatively easily changed by selecting the composition and adding various elements having different magnitudes of perpendicular magnetic anisotropy. Therefore, the conditions for manufacturing the recording layer of the magneto-optical disk and the conditions for recording the identification information can be optimally set according to the recording and reproducing conditions required for the magneto-optical disk.

In the first and second embodiments, the disc substrates 211 and 231 are made of polycarbonate resin, the dielectric layers 212, 214, 232 and 236 are made of SiN, the magnetic films are made of TbFeCo and GdFe.
Although a Co film and a TbFe film are used, glass or a plastic such as polyolefin or PMMA can be used for the disk substrates 211 and 231, and other dielectric materials such as AlN can be used for the dielectric layers 212, 214, 232 and 236. A nitride film, an oxide film such as TaO ₂ , a chalcogenide film such as ZnS, or a mixture film using two or more of these can be used as the magnetic film. Rare earth metal-transition metal based ferrimagnetic film of different MnB
A magnetic material having perpendicular magnetic anisotropy such as i, PtCo or the like can be used.

Further, in the second embodiment,
Although the perpendicular magnetic anisotropy of the recording magnetic film 235 of the recording layer having the three-layer structure is deteriorated, the reproducing magnetic film 233 and the recording magnetic film 2
35, the perpendicular magnetic anisotropy of at least one of the magnetic films or the perpendicular magnetic anisotropy of all the magnetic films of the reproducing magnetic film 233, the intermediate magnetic film 234, and the recording magnetic film 235 are deteriorated. Similar effects can be obtained.

<Third Embodiment> FIG. 40 is a sectional view showing the structure of an optical disk according to a third embodiment of the present invention. As shown in FIG. 40, a recording layer 303 made of a phase change material capable of reversibly changing between a crystalline phase and an amorphous phase is formed on a disk substrate 301 via a dielectric layer 302. . In the recording layer 303, a plurality of BCA sections 310 are recorded in the disk circumferential direction. On the recording layer 303, the intermediate dielectric layer 304, the reflective layer 30
5 are sequentially laminated, and an overcoat layer 306 is further formed thereon. Then, only the first optical disk has two disks having the overcoat layer 306 bonded together by the adhesive layer 307. Incidentally, a configuration in which two optical disks having the same configuration are bonded by a hot melt method may be used.

Next, a method of manufacturing an optical disk according to the present embodiment will be described. First, a disk substrate 301 on which guide grooves or prepits for tracking guide are formed by an injection molding method using a polycarbonate resin. Next, by subjecting the ZnSSiO ₂ target to high frequency (RF) sputtering in an Ar gas atmosphere,
An 80 nm-thick dielectric layer 302 made of an nSSiO ₂ film
To form Next, GeSbTe is used in an Ar gas atmosphere.
By performing RF sputtering on the alloy target, a recording layer 303 made of a GeSbTe alloy and having a thickness of 20 nm is formed on the dielectric layer 302. Then, Ar
By subjecting the ZnSSiO ₂ target to RF sputtering in a gas atmosphere, Zn
60 nm thick intermediate dielectric layer 30 made of SSiO ₂ film
4 is formed. Next, DC sputtering is performed on the AlCr target in an Ar gas atmosphere to form a 40-nm thick AlCr film on the intermediate dielectric layer 304.
The m reflective layers 305 are formed. Next, after the ultraviolet curable resin is dropped on the reflective layer 305, the ultraviolet curable resin is applied by a spin coater at a rotation speed of 3500 rpm, and the ultraviolet curable resin is cured by irradiating ultraviolet rays. The overcoat layer 306 having a thickness of 5 μm is formed thereon. Thereby, a first optical disc is obtained. On the other hand, a second optical disk is manufactured without forming an overcoat layer. Finally, the adhesive is cured by a hot melt method to form an adhesive layer 307, and the first optical disk and the second optical disk are bonded to each other.

Here, information is recorded on the recording layer 303 made of a Ge—Sb—Te alloy by irradiating a laser beam narrowed down to a minute spot to cause a local change in an irradiated portion, that is, a crystal. This is performed by utilizing the difference in optical properties between the phase and the amorphous phase based on the reversible structural change at the atomic level. Also,
The recorded information is reproduced by detecting a difference between a reflected light amount or a transmitted light amount with respect to a specific wavelength.

An optical disk having a recording layer made of a thin film capable of reversibly changing between two optically detectable states as described above is a DVD-RAM as a high-density rewritable medium. Etc.

The method of recording identification information (additional information) in the present embodiment is almost the same as in the first and second embodiments. That is, using a high-power laser such as a YAG laser and a one-way converging lens such as a cylindrical lens, a rectangular stripe-shaped laser beam is focused on the recording layer 303, and a plurality of BCA portions 310 are formed in the disk circumferential direction. Record each. In the optical disc of the present embodiment, when the recording layer 303 is irradiated with a laser beam having a higher output than that at the time of recording the main information, a structural change due to excessive crystallization due to phase transition occurs. Therefore, irreversibly the BCA unit 310
Can be recorded. In this case, the BCA unit 31
0 is preferably recorded as an irreversible state of the crystalline phase. Then, in this way, the BCA unit (identification information) 3
By recording 10, the amount of reflected light from the portion where the identification information is recorded and the amount of reflected light from other portions change, so that the identification information is reproduced by the optical head as in the first embodiment. can do. In this case, the variation in the amount of reflected light from the optical disk is preferably 10% or more, and the variation in the amount of reflected light can be set to 10% or more by changing the average refractive index to 5% or more. Further, in the case of a DVD-RAM, not only the recording layer undergoes an excessive structural change but also, as in the case of a DVD-ROM, a part of the protective layer or the reflective layer is lost, so that the amount of reflected light varies. Is greater than or equal to a predetermined value, and the BCA signal can be reproduced. Also,
Because of the bonding structure, there is no problem in reliability.

Next, the recording apparatus and recording method of the identification information (additional information) according to the present invention will be described in more detail with reference to the drawings. Here, in order to share the identification information with the recording / reproducing apparatus of the DVD disk, the details of the recording method of the DVD identification information and the technical contents using the format of the recording signal will be described. Will not be described. However, ASM
In a high-density magneto-optical disk such as O, since the identification information is reproduced using the optical head 255 having the configuration shown in FIG. 7, the recording signal detection method and the reproduction conditions are different.

FIG. 15 is a block diagram showing a laser recording apparatus according to the embodiment of the present invention, and FIG. 16 is a diagram showing a signal waveform and a trimming shape in the case of “RZ recording” according to the embodiment of the present invention. As shown in FIG.
In the present invention, RZ recording is used as a recording method of identification information. In the RZ recording, one unit time includes a plurality of time slots, for example, a first time slot 920.
a, a second time slot 921a, a third time slot 922a, etc., and when the data is “00”,
As shown in FIG. 16A, the first time slot 920
In a (between t = t1 and t = t2), a pulse 924a having a time width shorter than the time slot cycle, that is, the channel clock cycle T is recorded. In this case, FIG.
When a clock is generated in the clock signal generator 913 by the rotation pulse of the rotation sensor 915a of the motor 915 as shown in FIG.
Can eliminate the influence of the rotation unevenness. FIG. 16 (2)
As shown in the figure, a stripe 923a indicating "00" is trimmed by a laser in the first recording area 925a of the four recording areas on the disk.

When the data is "01", the data shown in FIG.
As shown in (3), in the second time slot 921b (between t = t2 and t = t3), a pulse 924b having a time width shorter than the time slot cycle, that is, the channel clock cycle T is recorded. You. As shown in FIG. 16D, on the disk, a stripe 9 indicating “01” is included in a second recording area 926b of the four recording areas.
23b is trimmed by the laser.

When the data is "10" or "11",
It is recorded in the third time slot 922a and the fourth time slot, respectively. As described above, a circular barcode as shown in FIG. 39A is recorded on the disk.

Here, "NRZ recording" used in conventional bar code recording will be described. In the case of NRZ recording, a pulse having the same time width as the time slot cycle, that is, the channel clock cycle T is recorded. In the case of the RZ recording of the present invention, the time width of one pulse is (1 /
n) Although T is sufficient, in the case of NRZ recording, a wide time width T is required as the pulse time width, and when T continues, the pulse time width is doubled and tripled. Widths 2T and 3T are required. In the case of laser trimming as in the present invention, it is practically difficult to change the line width of laser trimming because it is necessary to change the configuration of the apparatus itself, and it is not suitable for NRZ recording. Therefore, in the case of data of “00”, the first and third from the left are
A stripe having a time width T is formed in the second recording area,
In the case of data "10", a stripe having a time width of 2T is formed in the second and third recording areas from the left.

In the case of the conventional NRZ recording, the pulse width is 1
T and 2T indicate that the laser trimming of the present invention is not suitable. The stripe (bar code) recorded by the laser trimming of the present invention is shown in FIG.
Although reproduction is performed as shown in FIG. 31A or the experimental result diagram of FIG. 31A, the trimming line width varies for each optical disc, and it is difficult to control precisely. This is because, when trimming the reflective film or the recording layer of the optical disk, the line width of the trimming varies due to the variation of the output of the pulse laser, the thickness and material of the reflective film, and the thermal conductivity and the thickness of the disk substrate. Further, when bar codes having different line widths are provided on the same disk, the configuration of the recording device becomes complicated. For example, in the case of NRZ recording used in commodity barcodes, it is necessary to accurately adjust the line width of trimming to 1T or 2T, 3T of the channel clock, that is, nT. In particular, it is difficult to record while changing various line widths such as 2T and 3T for each bar. Since the format of the conventional product barcode is NRZ, when applied to the laser barcode of the present invention, it is difficult to accurately record different line widths such as 2T and 3T on the same disk, and the yield is reduced. I do. In addition, since the line width of laser trimming varies, stable recording cannot be performed, and demodulation becomes difficult. By using RZ recording as in the present invention, digital recording can be performed stably even if the line width of laser trimming changes. Also,
In the case of RZ recording, there is no need to modulate the laser power because only one type of line width is required for laser trimming.
The configuration of the recording device is simplified.

As described above, in the case of the laser barcode for an optical disk of the present invention, digital recording can be performed stably by combining RZ recording. Next, a case where RZ recording is PE-modulated will be described. FIG. 17 is a diagram showing signal waveforms and trimming shapes when the RZ recording of FIG. 16 is PE-modulated. First, when the data is “0”, as shown in FIG. 17A, the left time slot 920a of the two time slots 920a and 921a is placed between (t = t1 and t = t2). 17), a pulse 924a having a time width shorter than the cycle of the time slot, that is, the cycle T of the channel clock is recorded, and when the data is "1", as shown in FIG. (T = t2 and t = t2) in the right time slot 921b of the 921b.
3), a pulse 924b having a time width smaller than the time slot period, that is, the channel clock period T is recorded. On the disk, as shown in FIGS. 17 (2) and (4), a stripe 923a indicating "0" in the left recording area 925a and a stripe "1" in the right recording area 926b. Each of 923b is trimmed by a laser. Thus, the data is “01”
In the case of "0", as shown in FIG.
24c is recorded on the left side, ie, the time slot of “0”, the pulse 924d is recorded on the right side, ie, the time slot of “1”, and the pulse 924e is recorded on the left side, ie, the time slot of “0”. The stripes are trimmed by laser in the left, right, and left recording areas. In FIG. 17 (5), “01”
FIG. 17 shows a signal obtained by performing PE modulation on the data “0”.
As shown in (5), a signal always exists in each channel bit. That is, the signal density is always constant and DC-free. As described above, since the PE modulation is DC-free, even if a pulse edge is detected at the time of reproduction, it is resistant to fluctuation of low frequency components. Therefore, the demodulation circuit of the disk reproducing apparatus at the time of reproduction is simplified. Also, since there is always one pulse 924 every channel clock 2T,
The synchronization clock of the channel clock can be reproduced without using the PLL.

As described above, a circular barcode as shown in FIG. 39A is recorded on the disk. FIG.
When the data “01000” of (4) is recorded, in the PE-RZ recording of the present embodiment, a bar code 923 having the same pattern as the recording signal 924 of FIG.
It is recorded as shown in (2). When this bar code is reproduced by the optical pickup of the reproducing apparatus, the reflected signal is lost in a part of the pit modulation signal due to the lack of the reflective layer of the bar code, so that the waveform as shown in FIG. A signal is obtained. By passing the reproduced signal through a second-order or third-order Chebyhoff-type LPF 943 as shown in FIG. 23A, a signal having a waveform after passing through a filter as shown in FIG. 39 (6) is obtained. By slicing this signal using a level slicer, the reproduced data “01000” in FIG. 39 (7) is demodulated.

As described with reference to FIGS. 11A and 11B, when laser trimming recording is performed on a magneto-optical disk having a single-plate structure with excessive power, the overcoat layer (protective layer) is broken. Will be done. Therefore, it is necessary to form the protective layer again at the factory after performing the laser trimming recording with excessive power. For this reason, bar codes cannot be recorded at software companies or retail stores, and applications are expected to be greatly limited. Also, reliability can be an issue.

In the case of a magneto-optical disk having a single-plate structure, if only the recording layer is heat-treated and laser trimming recording is performed by changing the magnetic anisotropy in the direction perpendicular to the film surface,
Additional information can be recorded without destroying the overcoat layer (protective layer). In this case, there was no change in the magnetic properties even after the environmental test at a temperature of 85 ° C. and a humidity of 95% for 96 hours.

On the other hand, when the laser trimming recording of the present invention was applied to a bonded disk obtained by bonding two optical disks using a transparent substrate, it was confirmed by experiments that the protective layer remained without being destroyed. It was confirmed by observing with an optical microscope of 800 times. Further, similarly to the magneto-optical disk, the reflection film of the trimming portion did not change even after the environmental test at a temperature of 85 ° C. and a humidity of 95% for 96 hours. As described above, by applying the laser trimming recording of the present invention to a bonded disc such as a DVD, it is not necessary to form a protective layer again at a factory. Laser trimming recording of codes can be performed. For this reason, since it is not necessary to provide the information of the secret key of the encryption of the software company to the outside, security is greatly improved when security information, for example, a serial number for copy protection is recorded on the barcode. Also, as described below,
In the case of DVD, the trimming line width is set to 14T, that is, 1.8.
The bar code can be set to DVD
The pit signal can be separated from the pit signal, so that a barcode can be recorded by being superimposed on the pit recording area of the DVD. Thus, by applying the trimming method and the modulation recording method of the present invention to a bonded disc such as a DVD, secondary recording can be performed after factory shipment. In the case of a magneto-optical disk, secondary recording can be performed by a similar recording method.

Hereinafter, the operation of the laser recording apparatus shown in FIG. 15 will be described. As shown in FIG. 15, first, the ID number issued by the serial number generation unit 908 and the input data are combined in the input unit 909, and the encryption encoder 83
At 0, a signature or encryption is performed using a cryptographic function such as an RSA function or a DES function as needed, and error correction encoding is performed at the ECC encoder 907 and interleaving is performed. Next, the PE-RZ modulator 91
At 0, PE-RZ modulation is performed. The modulated clock in this case is generated by the clock signal generator 913 in synchronization with the rotation pulse from the motor 915 or the rotation sensor 915a. Next, based on the PE-RZ modulation signal, a laser emission circuit 911 generates a trigger pulse, and this trigger pulse is input to a high-power laser 912 such as a YAG laser established by a laser power supply circuit 929. As a result, a pulsed laser emits light, and the recording layer 2 of the single-plate magneto-optical disk 240 is
35, the recording layer 303 of the bonded disk 300 or the reflective film 802 of the bonded disk 800, and the recording layers 235, 303 or the reflective film 802 are degraded or recorded in the form of a bar code. The error correction method will be described later in detail. As the encryption method, a method of signing a public key code as a serial number with a secret key of a software company is adopted. In this case, since a person other than the software company does not have a secret key and cannot sign a new serial number, it is possible to prevent the issue of a serial number of an illegal company other than the software company. In this case, since the public key cannot be decrypted, the security is high. For this reason, forgery can be prevented even when the public key is recorded on a disk and transmitted to the player. Magneto-optical disk 240 and DVD-RA
The M300 or DVD-ROM disc 800 is discriminated by the disc discriminating unit 260 by means such as reading reflectance or disc type identification information. . Thus, the BCA can be stably recorded on the magneto-optical disk 240.

Here, the condensing section 914 of the laser recording apparatus
Will be described in detail with reference to FIG. FIG.
As shown in FIG. 8A, the light from the laser 912 is incident on the condensing unit 914, becomes parallel light by the collimator 912a, is focused by the cylindrical lens 917 only in one direction in the circumferential direction of the optical disk, and It becomes long striped light. This light is cut by a mask 918 and then converged by a converging lens 919 to the recording layer 235 of the magneto-optical disk 240 or a DVD-RAM.
An image is formed on the recording layer 303 of the 300 or the reflective film 802 of the DVD-ROM disc 800, and the recording layer 235,
303 or the reflective film 802 is recorded or removed in a striped manner. In this case, the mask 918 limits the four directions of the stripe. However, in practice, it is only necessary to limit one direction on the outer peripheral side in the longitudinal direction of the stripe. Thus, a stripe 923 as shown in FIG. 18B is recorded on the disk. In the case of PE modulation, there are three types of stripe intervals, 1T, 2T, and 3T, but if the intervals are shifted, jitter occurs and the error rate increases. In the present invention, the motor 915
The clock generation unit 913 generates a recording clock in synchronization with the rotation pulse of
5, that is, the magneto-optical distor 240 and the DVD-RAM 30
0, a stripe 923 is recorded at an accurate position according to the rotation of the DVD-ROM disc 800. Therefore, jitter is reduced. By providing laser scanning means, a continuous wave laser can be scanned in the radial direction to form a bar code.

Here, the features of the format will be described with reference to FIG. As shown in FIG.
In the case of a VD disc, all data is recorded in CLV. However, in the stripe 923 of the present invention, the address information is recorded in CAV by being superimposed on the pre-pit signal in the lead-in data area recorded in CLV (overwriting). As described above, the CLV data is recorded by the pit pattern of the master, and the CAV data is recorded by dropping the reflection film by the laser.
Because of overwriting, one of barcode-shaped stripes
Pits are recorded between T, 2T and 3T. By using the information of the pits, tracking of the optical head becomes possible, and _Tmax or T
_{Since min} can be detected, this signal can be detected to control the rotational speed of the motor. Satisfies stripe trimming width t and the pit clock T and (pit) is t> the relationship between 14T (pit), it is possible to detect the T _min, applying a rotational speed control of the motor by detecting the signal Can be. When t is shorter than 14T (pit), the pulse width becomes the same and the stripe 9
Since the pit cannot be distinguished from the pit, demodulation cannot be performed. Further, in order to read the address information of the pit at the same radial position as the stripe, the length of the address area 944 is provided for one or more frames of the pit information, so that the address information can be obtained and the track jump can be performed. Further, as shown in FIG. 24, the ratio of the stripe to the non-stripe, that is, the duty ratio is set to 50% or less.
By setting (S) <T (NS), the substantial reflectance is reduced only by 6 dB, so that the focus of the optical head is stably performed. Depending on the player, tracking control cannot be performed depending on the player depending on the presence of the stripe. However, since the stripe 923 is CAV data, driving is performed using a rotation pulse from a hall element or the like of the motor 17 to rotate the CAV. For example, it can be reproduced by an optical pickup.

In the case of a magneto-optical disk, the fluctuation range of the reflectance is 10% or less, so that there is no influence on the focus control or the like. FIG. 20 shows a flowchart of an operation procedure when pit data of an optical track is not normally reproduced in the stripe area. When the optical disk is inserted (step 930a), first, the optical head moves to the inner peripheral portion of the optical disk (step 930b), and FIG.
To the area of the stripe 923 shown in FIG. In this region, the pit signals in the region of the stripe 923 may not all be properly reproduced, so that the rotation phase control performed in the case of CLV cannot be applied. Thus, by measuring the T _max or T _{mi n} and the frequency of rotation sensor and a pit signal of the Hall element of the motor, the rotational speed control is applied (step 930c).
Next, it is determined whether or not there is a stripe (step 930i). If there is no stripe, the optical head moves to the outer peripheral portion of the optical disk (step 930f).
If there is a stripe, stripe (barcode)
Is reproduced (step 930d). Next, it is determined whether or not the reproduction of the barcode has been completed (step 930).
e) If the reproduction of the barcode has been completed, the optical head moves to the outer peripheral portion of the optical disk (step 93).
0f). Since no stripe exists in this area, the pit signal is completely reproduced, and focus and tracking servo are normally applied. In addition, since the pit signal is completely reproduced in this manner, normal rotation phase control becomes possible (step 930g), and CLV rotation is performed. Therefore, the pit signal is normally reproduced in step 930h.

As described above, by switching between the two rotation controls of the rotation speed control and the rotation phase control based on the pit signal, it is possible to reproduce two kinds of different data, ie, stripe (bar code) data and pit recorded data. Can be. In this case, since the stripe (bar code) is located at the innermost periphery of the optical disk, the position of the optical head in the disk radial direction is measured by using the stopper information of the optical head and the address information of the pit signal, thereby controlling the rotation speed. It is possible to reliably switch between the two rotation controls of the rotation phase control.

Here, a format suitable for high-speed switch recording will be described with reference to the data structure of a synchronization code shown in FIG. The fixed pattern in FIG.
The fixed pattern is usually “01000111” or the like in which 0 and 1 are the same number, but in the present invention, this data configuration is intentionally adopted. In order to perform recording, first, two or more pulses must not be applied to 1 t. As shown in FIG.
Since Z recording is used, high-speed switch recording is possible. However, since the synchronization code in FIG. 22A is arranged as an irregular channel bit, in the normal method, 1 is used.
There may be two pulses at t, in which case high speed switch recording cannot be performed. In the present invention, for example, “01000110” is used.
Accordingly, FIG. 22 as shown in (b), T ₁ the right one pulse, the T ₂ 0 pulse, T ₃ in the right one pulse, T ₄
In this case, there is one pulse on the left, and there are no two pulses in each time slot. Therefore, by adopting the synchronization code of the present invention, high-speed switch recording becomes possible,
The production speed can be doubled.

Next, the recording / reproducing apparatus will be described. FIG. 14 is a block diagram of the recording / reproducing apparatus. Here, the description will focus on demodulation. First, the signal output of the stripe
The LPF 943 removes high frequency components due to the pits. In the case of a DVD, there is a possibility that a signal of a maximum of 14T of T = 0.13 μm is reproduced. In this case, FIG.
Experiments have confirmed that high-frequency components due to pits can be removed by passing through a secondary or tertiary Chebyhoff-type LPF 943 as shown in FIG. That is, if a secondary or higher order LPF is used, the pit signal and the barcode signal can be separated, and the barcode can be reproduced stably. FIG. 23B shows a simulation waveform in the worst case.

As described above, by using the LPF 943 of the second order or higher, the pit reproduction signal can be almost removed and the stripe reproduction signal can be output, so that the stripe signal can be reliably demodulated.

Returning to FIG. 14, the description will be continued. PE-R
Digital data is demodulated in a Z demodulation unit 930a,
This data is error-corrected in the ECC decoder 930b. Then, the deinterleaving section 930d deinterleaves the signal, calculates the Reed-Solomon code toward the RS decoder 930c, and performs error correction. In the present invention, as shown in the data configuration of FIG. 21A, interleaving and Reed-Solomon error correction encoding are performed using an ECC encoder 907 at the time of recording as shown in FIG. Therefore, by adopting this data structure, if the byte error rate before correction is 10 ^-4 as shown in FIG.
Only one out of every ^seven errors occurs. As shown in FIG. 22A, as this data configuration, one Syn code is used for every four synchronization codes in order to reduce the data length of Code.
By adopting a configuration with c Code, Sync
This is one-fourth the code, and the efficiency is increased.

Here, the scalability of the data structure will be described with reference to FIG. In the present invention,
As shown in FIG. 22C, the recording capacity can be arbitrarily increased or decreased in units of 16 B, for example, in the range of 12 B to 188 B. As shown in FIG. 21A, n = 1 to n =
Up to 12 can be changed. For example, FIG.
As shown in the figure, when n = 1, the data rows are 951a, 9
There are only four lines 51b, 951c, and 951d.
The CC rows are 952a, 952b, 952c, and 952d. The data row 951d becomes the EDC 4b. Then, assuming that data rows from 951e to 951z all contain 0 data, the operation of the error correction code is performed. Such ECC encoding is shown in FIG.
Is performed by the ECC encoder 907 of the laser recording apparatus, and is recorded as a bar code on the disk. n = 1
In the case of (1), the data of 12b can be recorded in the 51-degree angle range on the disk. Similarly, when n = 2, data of 18b can be recorded, and n = 2
In the case of 12, 271b data is transferred to 33 on the disk.
It can be recorded in an angle range of 6 degrees.

In the case of the present invention, this scalability is significant. In the case of laser trimming, production tact becomes important. In order to trim one line at a time, a low-speed apparatus requires ten seconds or more to record a maximum capacity of several thousand lines. Since the production tact of the disc is 4 seconds, the production tact is reduced. On the other hand, the use of the present invention
Initially, the disc ID number is mainly used, and may be about 10b. Recording 271b while writing 10b increases the processing time of the laser by a factor of six, thereby increasing the production cost. By using the scalability method of the present invention, production cost and time can be reduced.

In the ECC decoder 930b of the recording / reproducing apparatus shown in FIG. 14, for example, when n = 1 shown in FIG. E
By performing the CC error correction operation, the data of 12b to 271b can be corrected by the same program.

As shown in FIG. 24, in the case of 1T, the pulse width is 4.4 μs, which is about a half of the stripe interval of 8.92 μs. In the case of 2T, the stripe interval is 1
In the case of 3.84 μs, the pulse width is 4.4 μs, and in the case of 3T, the pulse width is 4.4 μs with respect to the stripe interval of 26.76 μs. Becomes the pulse portion (the reflectance is almost 0).
Accordingly, a disk having a standard reflectance of 70% has a reflectance of about 2/3, that is, about 50%, and can be reproduced by a general ROM disk player.

Further, in the case of a magneto-optical disk, the average refractive index of the recording layer does not change and the average reflectance changes less than 10%, so that the level change of the reproduced waveform is small and compatibility with DVD players is easy. It is.

Next, the reproduction procedure will be described with reference to the flowchart of FIG. When the disc is inserted,
First, TOC (Control Data) is reproduced (step 940a). As shown in FIG. 19, in the optical disc of the present invention, a stripe presence / absence identifier 937 is recorded as a pit signal in the TOC of the TOC area 936. Therefore, when the TOC is reproduced, it can be determined whether or not the stripe is recorded. Next, stripe presence / absence identifier 9
It is determined whether 37 is 0 or 1 (step 940b). When the stripe presence / absence identifier 937 is 0, the optical head moves to the outer peripheral portion of the optical disk, switches to rotation phase control, and normal CLV reproduction is performed (step 940).
f). If the stripe presence / absence identifier 937 is 1, it is determined whether or not the stripe is recorded on the surface opposite to the reproduction surface, that is, on the back surface (whether the back surface presence identifier 948 is 1 or 0) (step 940h). Backside presence identifier 948 is 1
In the case of (1), the recording layer on the back surface of the optical disk is reproduced (step 940i). If the back side of the optical disc cannot be automatically reproduced, a back side reproduction instruction is output and displayed. If it is determined in step 940h that a stripe is recorded on the surface being reproduced, the optical head moves to the area of the stripe 923 on the inner peripheral portion of the optical disk (step 940c), and switches to rotation speed control.
The CAV is rotated to reproduce the stripe 923 (step 940d). Next, it is determined whether or not the reproduction of the stripe 923 has been completed (step 940e). If the reproduction of the stripe 923 has been completed, the optical head moves to the outer peripheral portion of the optical disk and switches to the rotation phase control again. Normal CLV reproduction is performed (step 940).
f) The data of the pit signal is reproduced (step 94).
0 g).

As described above, since the stripe presence / absence identifier 937 is recorded in the pit area such as TOC,
The stripe 923 can be reliably reproduced. In the case of an optical disk in which the stripe presence / absence identifier 937 is not defined, tracking is not performed in the area of the stripe 923, so that it takes time to determine the stripe 923 and the scratch. In other words, even when there is no stripe, the stripe is always read, so it is necessary to check in steps such as whether the stripe is really present or further on the inner periphery, and extra time is required for the rise. In addition, since the stripe back surface existence identifier 948 is recorded, it can be seen that the stripe 923 is recorded on the back surface. Therefore, even in the case of a double-sided optical disk such as a DVD, the barcode stripe 923 can be reliably reproduced. In the case of a DVD-ROM, since the stripe of the present invention penetrates both reflective films of the double-sided disk, it can be read from the back surface. The stripe backside presence identifier 948 can be viewed from the backside by reproducing the stripe 923 with the opposite sign when reproducing. In the present invention, as shown in FIG. 22A, "01000110" is used as a synchronization code. Therefore, when reproduced from the back side, "0110001"
A sync code of "0" is detected. Therefore, it can be detected that the barcode stripe 923 is being reproduced from the back surface. In this case, in the recording / reproducing apparatus of FIG. Conversely, by demodulating the code, even if the double-sided disc is reproduced from the back side, it is possible to normally reproduce the penetrated barcode stripe 923. Further, as shown in FIG. The presence / absence identifier 939 and the stripe recording capacity are recorded, so if the first trimming stripe 923 has already been recorded, it is calculated how much capacity can be recorded in the second trimming stripe 938. Therefore, when the recording apparatus of FIG. 15 performs the second trimming based on the TOC data, As a result, it is possible to prevent the stripe 923 of the first trimming from being destroyed due to recording more than 360 °, as shown in FIG. By providing a blank portion 949 of one or more pit signal frames between the first trimming stripe 923 and the second trimming stripe 938, the previous trimming data is prevented from being destroyed. be able to.

Further, as shown in FIG. 22B, since the trimming number identifier 947 is recorded in the synchronous code section, the data of the first trimming stripe 923 and the second trimming stripe 938 are stored. Can be identified. If the trimming number identifier 947 does not exist, the first stripe 923 and the second stripe 923 in FIG.
This means that the stripe 938 cannot be determined for the first time.

Next, the procedure from content to disc production will be described with reference to FIG. As shown in FIG. 33, in the disc manufacturing unit 19, first, an original content 3 such as a movie is compressed by an MPEG encoder 4 into a compressed video such as MPEG, which is block-blocked, variable-length coded, and image-compressed. Signal. This signal is scrambled by the encryption encoder 14 using the business encryption key 20. The scrambled compressed video signal is recorded as a pit-shaped signal on the master 6 by the master maker 5. With the master 6 and the molding machine 7,
A large number of disk substrates 8 on which pits are recorded are manufactured,
A reflection film such as aluminum is formed by the reflection layer forming machine 15. The two disk substrates 8 and 8a are bonded by a bonding machine 9 to complete a bonded disk 10. In the case of a magneto-optical disk, the compressed video signal is recorded on the recording layer as a magneto-optical signal. In the case of a single plate structure, the disk 240a
Is completed. Similarly, in the case of a DVD-RAM, the compressed video signal is recorded on a recording layer, and two disc substrates are pasted together by a pasting machine 9.
The bonded disc 300 is completed. DVD-RAM
In this case, two types of disk configurations are possible: a single type having a recording layer only on one side and a double type having a recording layer on both sides.

Next, the operation of the BCA level slice will be described with reference to FIGS. 38 and 39. FIG. 38 (1)
As shown in FIG. 19, in BCA recording by laser, the aluminum reflective film 809 of the bonded disc 800 is irradiated with a laser beam from a pulse laser 808 to trim the aluminum reflective film 809, thereby forming a stripe-shaped low reflective portion 810. Is recorded based on the PE modulation signal. As a result, as shown in FIG.
A CA stripe is formed. When this BCA stripe is reproduced by a normal optical head, there is no reflected signal from the BCA portion. Therefore, as shown in FIG. 38 (3), the missing signal portions 810a and 810 where the modulation signal is intermittently lost.
b, 810c occurs. The modulated signal of the pit 8-16 modulation is sliced at the first slice level 915, and the main signal is demodulated. On the other hand, since the signal level of the missing signal portion 810a and the like is low, the slice can be easily sliced at the second slice level 916. Bar code 923a, 923b shown in FIG. 39 (2), by the level slice at a second slice level S ₂ shown in FIG. 39 (5), can be reproduced by the conventional optical pickup. FIG.
As shown in (6), by slicing the signal pit signal of high frequency has been suppressed by the LPF in the second slice level S _2, 2-valued signal is obtained. And this 2
By performing PE-RZ demodulation of the coded signal, FIG.
A digital signal as shown in (7) is output. The state of the actual reproduced signal is as shown in FIG.

Next, the demodulation operation will be described with reference to FIG. As shown in FIG.
No. 00 has a configuration in which two transparent substrates are bonded together so that the recording layer 802a is located inside.
Is a single layer or a two-layer recording layer 802a, 802b. When the number of recording layers is two, the optical head 255
The control data of the first recording layer 802a close to
Stripe presence / absence identifier 9 indicating whether or not BCA exists
37 (see FIG. 19) are recorded. In this case, BC
Since A exists in the second recording layer 802b, first the first
Of the second recording area 91
The optical head 255 is moved to the radial position of the control data existing on the innermost circumference of the control data 9. Since the control data is main information, it is EFM or 8-15 or 8-16 modulated. Only when the stripe presence / absence identifier 937 in the control data is “1”, the one-layer / two-layer part switching unit 827 focuses on the second recording layer 802b to reproduce the BCA. When sliced at the general first slice level 915 as shown in FIG. 38 (3) using the first level slicer 590, it is converted into a digital signal. This signal is sent to the EFM demodulation unit 925 or the 8-15 modulation demodulation unit 926 or 8-16 in the first demodulation unit 928.
The signal is demodulated by the modulation / demodulation unit 927, error-corrected by the ECC decoder 36, and output as main information. The control data in the main information is reproduced, and the BCA is read only when the stripe presence / absence identifier 937 is “1”.
When the stripe presence identifier 937 is “1”, the CPU 9
23 issues an instruction to the one-layer / two-layer part switching unit 827 to drive the focus adjustment unit 828 so that the first recording layer 802 a
Is switched to the recording layer 802b. At the same time, the radial position of the second recording area 920 (in the case of the DVD standard, 22.3 mm to 23.5 m on the inner peripheral side of the control data)
The BCA is read by moving the optical head 255 to (BCA recorded during m). In the BCA area, FIG.
A signal in which the envelope is partially missing as shown in FIG. 8 (3) is reproduced. By setting the second slice level 916 having a light amount lower than the first slice level 915 in the second level slice section 929, the missing portion of the reflection portion of the BCA is detected, and a digital signal is output. This signal is supplied to the PE-RZ demodulation section 930a of the second demodulation section 930.
, And ECC decoded by the ECC decoder 930b, and output as BCA data as sub information.
As described above, the main information is demodulated and reproduced by the first demodulation unit 928, and the BCA data as the sub information is demodulated and reproduced by the second demodulation unit 930. FIG. 24A shows a reproduced waveform before passing through the LPF 943, FIG. 24B shows a processing dimensional accuracy of the slit of the low reflection portion 810, and FIG. 23B shows a simulation waveform after passing through the LPF 943. It is difficult to reduce the width of the slit to 5 to 15 μm or less. Also, 2
If the data is not recorded on the inner circumference of 3.5 mm, the recorded data will be destroyed. In the case of DVD, the shortest recording cycle = 3
Due to the limitations of 0 μm and a maximum radius of 23.5 mm, the maximum capacity after formatting is limited to 188 bytes or less.

Here, the method of setting the second slice level 916 and the operation of the second level slice unit 929 described with reference to FIG. 14 will be described in detail and concretely. FIG. 26 shows a detailed view of only the second level slice section 929. FIG. 27 shows a waveform diagram required for this explanation.

As shown in FIG. 26, the second level slice section 929 includes a light quantity reference value setting section 588 for supplying a second slice level 916 to the second level slicer 587,
And a 2 frequency divider 587d for dividing the output signal of the second level slicer 587. The light amount reference value setting unit 588 includes an LPF 588a and a level conversion unit 58.
8b.

Hereinafter, the operation will be described. In the BCA area, due to the presence of BCA, a signal whose envelope is partially missing as shown in FIG. 27A is reproduced. The reproduced signal includes a high frequency component due to the pit signal and BCA
Low frequency components due to the signal are mixed. But LP
By F943, the high-frequency signal component of the 8-16 modulation is suppressed, and a low-frequency signal 932 of only the BCA signal as shown in FIG. 27 (2) is input to the second level slice section 929.

When the low frequency signal 932 is input to the second level slice section 929, the light quantity reference value setting section
An LPF 588a having a larger time constant than the PF 943, that is, an LPF 588a capable of extracting a lower frequency component, allows a further lower frequency component (almost a DC component) of the low frequency signal 932 to pass therethrough, and a level converter 588b sets an appropriate level. , And outputs a second slice level 916 as indicated by the thick line in FIG. 27 (2). As shown in FIG. 27 (2), the second slice level 916 is tracking the envelope.

In the case of the present invention, when the BCA is read, the rotation phase control cannot be performed, and the tracking control cannot be performed. Therefore, the envelope is shown in FIG.
It fluctuates constantly as in 7 (1). If the slice level is fixed, the slice is erroneously sliced by the fluctuating reproduction signal, and the error rate is deteriorated. Therefore, it is not suitable for data. However, in the circuit of FIG. 26 of the present invention, since the second slice level is constantly corrected in accordance with the envelope, erroneous slicing is greatly reduced.

As described above, according to the present invention, the second level slicer 587 slices the low-frequency signal 932 at the second slice level 916 without being affected by the fluctuating envelope. 2 as shown
Output the digitized digital signal. The signal is inverted at the rise of the binarized digital signal output from the second level slicer 587, and a digital signal as shown in FIG. 27 (4) is output. FIG. 28 shows a specific circuit of the frequency separation means 934 and the second level slice unit 929 at this time.

As described above, by setting the second slice level 916, an 8-16 modulation signal generated by a difference in reflectivity of a disk to be reproduced, a change in light amount due to aging of a reproduction laser, or a track cross at the time of reproduction. Can absorb the low frequency level (DC level) fluctuation of
It is possible to realize an optical disk reproducing apparatus that can reliably slice a BCA signal.

Now, another method of setting the second slice level 916 will be described. FIG. 29 shows another circuit diagram of the frequency separation means 934 and the second level slice section 929. As shown in FIG. 29, the LP of the frequency separation means 934
The F943 includes a first LPF 943a having a small time constant and a second LPF 943b having a large time constant. The second level slicer 587 of the second level slicer section 929 includes an inverting amplifier 587a and a DC regeneration circuit 587b.
And a comparator 587c and a ２ frequency divider 587d. FIG. 31 is a waveform diagram necessary for this explanation.
Shown in

Hereinafter, the operation will be described. In the BCA area, due to the presence of the BCA, a signal in which the envelope is partially missing as shown in FIG. 31A is reproduced. This reproduced signal is input to the first LPF 943a and the second LPF 943b of the LPF 943. 1st L with small time constant
In the PF 943a, a high-frequency signal of 8-16 modulation is removed from the reproduced signal, and a BCA signal is output. In the second LPF 943b having a large time constant, the DC component of the reproduction signal passes and the DC component of the reproduction signal is output. 1st LPF
When the signal in which the high-frequency signal of the 8-16 modulation is suppressed is input from 943a, the inverting amplifier 587a outputs the first LPF.
The amplitude reduced during passage through 943a is amplified. The amplified signal is DC-reproduced at the GND level in the DC regeneration circuit 587b, and a signal as shown in FIG. 31 (3) is input to the comparator 587c. On the other hand, the second LPF
When the DC component of the reproduction signal is input from the 943b, the light level reference value setting unit 588 adjusts the level to an appropriate level by resistance division or the like, and the second slice level 916 as shown in FIG. Is input to The comparator 587c slices the output signal of the DC regeneration circuit 587b at the second slice level 916, and
A binary digital signal as shown in (4) is output. In the 2 divider 587d, the comparator 587c outputs 2
The signal is inverted at the rise of the digitized digital signal,
A digital signal is output.

FIG. 30 shows a specific circuit of the frequency separation means 934 and the second level slice section 929 at this time.
As described above, the second slice level 916 is set and B
By reproducing the CA signal, the difference in the reflectivity of the disk to be reproduced, the fluctuation of the amount of light due to the aging of the reproducing laser, and the DC level fluctuation of the 8-16 modulated signal caused by the track cross at the time of reproduction are reliably absorbed. An optical disc reproducing apparatus capable of slicing a BCA signal can be realized. Further, when this circuit is constituted by a discrete circuit, it is possible to realize a BCA reproduction circuit having the smallest number of elements and being reliable.

If the 、 ２ frequency divider 587d is used, the clock frequency of the PE modulation signal can be reduced to half when this signal is taken into the CPU and demodulated by software. For this reason, even when a CPU having a low sampling frequency is used, it is possible to reliably detect a signal change point.

This effect can also be obtained by lowering the rotation speed of the motor during reproduction. This is shown in FIG.
This will be described with reference to FIG. When a BCA playback command arrives, the CP
The rotation speed deceleration signal 923b is sent to the rotation control unit 26 by U923. Then, the rotation control unit 26 sets the motor 1
7 is reduced to half or quarter. For this reason, even if the frequency of the reproduction signal decreases and a CPU with a low sample frequency is used, demodulation can be performed by software and reproduction can be performed even with a BCA having a small line width. In the case of BCA, a BCA stripe having a small line width may be formed depending on a factory. However, by lowering the rotation speed, processing can be performed by a low-speed CPU. As a result, the error rate during BCA reproduction is improved, and the reliability is improved.

In FIG. 14, B is set at a normal speed such as 1 × speed.
Only when an error occurs at the time of reading the CA and reproducing the BCA, the CPU 923 sends a deceleration command to the rotation control unit 26 to reduce the rotation speed of the motor 17 to half. If this method is adopted, when reading BCA of average line width, BCA
The substantial reading speed of CA does not decrease at all. An error occurs when the line width is small, but only in this case, the error can be detected by reading the BCA at half speed. As described above, by lowering the reading speed only when the line width of the BCA is narrow, it is possible to prevent the reproduction speed of the BCA from lowering.

In FIG. 14, the frequency separating means 9
Although the LPF 943 is used as 34, the LPF 943 may be constituted by an envelope tracking circuit, a peak hold circuit, or the like as long as it can suppress a high-frequency signal of 8-16 modulation from a reproduced signal in the BCA area.

Further, the frequency separation means 934 and the second level slicer 929 directly binarize the reproduced signal in the BCA area, and then input it to a microcomputer or the like, and digitally process the reproduced signal using the points having different edge intervals. 16 signals and BCA
It may be constituted by means for performing processing for discriminating the time axis of the signal and for substantially suppressing the high-frequency signal of 8-16 modulation.

The modulation signal is recorded in pits using the 8-16 modulation method, and the high frequency signal 933 shown in FIG. 14 is obtained. On the other hand, the BCA signal becomes a low frequency signal 932.
Thus, in the case of the DVD standard, the main information is up to about 4.5.
MHz high-frequency signal 933, and the sub-information has a period of 8.9.
Since the low-frequency signal 932 is 2 μs, that is, about 100 kHz, the sub-information can be easily frequency-separated using the LPF 943. By using the frequency separation means 934 including the LPF 943 as shown in FIG. 14, two signals can be easily separated. In this case, LPF
943 may have a simple configuration.

The above is the outline of BCA. FIG. 32 is a block diagram of a disc manufacturing apparatus and a reproducing apparatus. As shown in FIG. 32, the disc manufacturing unit 19
An OM-type or RAM-type bonded disk or a single-plate disk 10 is manufactured. In the disk manufacturing apparatus 21, the disks 10a, 10b, 10c,.
Using the CA recorder 13, B including identification codes 12 a, 12 b, and 12 c such as different IDs for each disc
The CA data 16a, 16b, and 16c are PE-modulated by the PE modulator 17 and laser-trimmed using a YAG laser.
CAs 18a, 18b and 18c are formed. Hereinafter, BC
The entire disc on which A18 is recorded is copied to the BCA disc 1
1a, 11b and 11c. As shown in FIG. 32, the pit portions or recording signals of these BCA disks 11a, 11b, 11c are exactly the same. However, IDs different from 1, 2, and 3 are recorded in the BCA 18 for each disc. A content provider such as a movie company stores this different ID in the ID database 22. At the same time, the BCA data is read by a barcode reader 24 that can read the BCA when the directory is shipped, and the supply destination of the disk of which ID is supplied to which system operator 23, that is, a CATV company, a broadcasting station or an airline company The supply time is stored in the ID database 22.

As a result, the record of which ID of the disk was supplied to which system operator is stored in the I
It is recorded in the D database 22. For this reason, in the future, if a large number of illegal copies are circulated using a specific BCA disk as a source, the B
Whether an illegal copy has been performed from the CA disk 11 can be traced by checking a true watermark. This operation will be described in detail later, but since the ID numbering by BCA virtually plays the same role as the watermark as a whole system, it is called "pre-watermarking".

Here, data to be recorded in the BCA will be described. An ID is generated from the ID generation unit 26. Also, from the watermark creation parameter generation unit 27,
A watermark creation parameter is generated based on the ID or by a random number. Then, the ID and the watermark creation parameter are mixed, and the digital signature unit 28 signs using the secret key of the public key cryptographic function. The ID, the watermark creation parameter, and the signature data thereof are BCA recorded on each of the disks 10a, 10b, and 10c using the BCA recorder 13. Thereby, the BCAs 18a, 18b, 18c are formed.

The BCA disks 11a, 11b, 11
In the case of recording main information such as a video signal in c, as shown in FIG.
It is read by the A playback unit 39. The watermark adding unit 264 superimposes the BCA signal to convert the video signal, and converts the converted video signal by the recording circuit 272 to the BCA disks 11a, 11b, and 11c (300 (240, 800) in FIG. 41). To record. Also, B
When reproducing a video signal from a BCA disk 300 (240, 800) on which a video signal on which a CA signal is superimposed is recorded, first, the BCA signal of the disk is read by the BCA reproduction unit 39 and detected as ID1 of the disk. . The video signal on which the watermark is superimposed is detected as the disc ID 2 by the watermark reproducing unit.
ID1 read from the BCA signal and disc ID2 read from the watermark of the video signal are compared by a comparator, and if they do not match, the reproduction of the video signal is stopped. As a result, a video signal cannot be reproduced from a disc that has been illegally copied and on which a watermark different from the BCA signal is superimposed. On the other hand, if they match, the ID read from the BCA signal
The video signal on which the watermark is superimposed is descrambled by the descrambler 31 using the decryption key including the information, and is output as the video signal.

Now, the BC which has been "pre-watermarked" by the disk manufacturing apparatus 21 as described above.
The A disks 10a, 10b, and 10c are used as playback devices 25a and 25c of the system operators 23a, 23b, and 23c.
b, 25c. In FIG. 32, some blocks of the retransmitting device 28 are omitted due to drawing creation.

The operation of the system operator will be described with reference to FIGS. 34 and 35. FIG. 34 is a block diagram showing details of the retransmitting device, and FIG. 35 is a diagram showing a waveform on the time axis and a waveform on the frequency axis of the original signal and each video signal.

As shown in FIG. 34, the retransmitting device 28 installed at the CATV station or the like is provided with a reproducing device 25a dedicated to the system operator.
Has a BCA-equipped disc 11 supplied by a movie company, etc.
a is attached. The main information of the signal reproduced by the optical head 29 is reproduced by the data reproducing unit 30, descrambled by the descrambler 31, and after the original signal of the image is expanded by the MPEG decoder 33, the watermark unit 34 Sent to In the watermark unit 34, first, the original signal shown in FIG. 35 (1) is input, and a frequency conversion unit 34a such as FFT is used.
Is converted from the time axis to the frequency axis. Thereby, the frequency spectrum 35a as shown in FIG.
Is obtained. The frequency spectrum 35a is mixed with an ID signal having the spectrum shown in FIG. The spectrum 35b of the mixed signal is, as shown in FIG.
It is not different from the frequency spectrum 35a of the original signal shown in (2). That is, the ID signal is spread spectrum. This signal is converted from the frequency axis to the time axis by an inverse frequency converter 37 such as an IFFT to obtain a signal which is not different from the original signal (FIG. 35 (1)) as shown in FIG. 35 (5). Since the ID signal is spectrum-spread in the frequency space, the deterioration of the image signal is small.

Here, a method of creating the ID signal 38 will be described. BCA disc 1 by BCA playback unit 39
The signature of the BCA data reproduced from 1a is verified by the digital signature verification unit 40 using a public key or the like sent from the IC card 41 or the like. In the case of NG, the operation stops. In the case of OK, since the data has not been tampered with, the ID is directly used as the watermark data creation unit 4.
1a. Here, using the watermark creation parameter included in the BCA data, FIG.
A watermark signal corresponding to the ID signal shown in (3) is generated. Note that the watermark signal may be generated by calculating the watermark from the ID data or the card ID of the IC card 41.

In this case, if the correlation between the ID and the watermark creation parameter is completely eliminated, and the watermark creation parameter and the ID are recorded in the BCA,
The watermark cannot be inferred from the ID by calculation. That is, only the copyright holder knows the relationship between the ID and the watermark. For this reason,
It is possible to prevent an unauthorized copy company from issuing a new ID and illegally issuing a watermark.

On the other hand, a specific operation is used to generate a spectrum signal from the card ID of the IC card 41 and add it to the ID signal 38 to obtain the card ID of the IC card 41.
Can be embedded in a video output signal as a watermark. In this case, since both the distribution ID of the software and the ID of the reproducing apparatus can be confirmed, the tracing of the illegal copy, that is, the trace, is further facilitated.

The video output signal of the watermark section 34 is sent to the output section 42. When the retransmitting device 28 transmits the compressed video signal, the video output signal is compressed by the MPEG encoder 43, scrambled by the scrambler 45 using the encryption key 44 unique to the system operator, and transmitted from the transmission unit 46 to the network. Or transmitted to the viewer via radio waves. In this case, the compression parameter information 4 such as the transfer rate after compressing the original MPEG signal
7 is the MPEG decoder 33 to the MPEG encoder 43
, So even for real-time encoding,
Compression efficiency can be increased. The compressed audio signal 4
8 is not expanded or compressed by bypassing the watermark section 34, so that the sound quality does not deteriorate.

Next, when the compressed signal is not transmitted, the video output signal 49 is scrambled as it is and
a to the viewer via a network or radio waves.
In the case of an airplane screening system, scrambling is unnecessary. Thus, the video signal containing the watermark is transmitted from the disk 11a with BCA.

In the case of FIG. 34, there is a possibility that an illegal copy trader extracts a signal between blocks from a bus on the way, thereby bypassing the watermark section 34 and extracting a video signal. To prevent this, the descrambler 31, the MPEG decoder 33, and the watermark unit 3
The bus between the four authentication units 32a and 32b
b, 32c and the mutual authentication unit 32d are encrypted by the shake hand method. The encrypted signal obtained by encrypting the signal by the mutual authentication unit 32c on the transmission side is transmitted to the mutual authentication unit 3 on the reception side.
2d, the mutual authentication unit 32c and the mutual authentication unit 32d communicate with each other, that is, perform handshake. Only when this result is correct, the mutual authentication unit 32d on the receiving side decrypts the encryption. The same applies to the mutual authentication unit 32a and the mutual authentication unit 32b. Thus, in the method of the present invention, the encryption is not released unless mutual authentication is performed. For this reason, even if a digital signal is extracted from an intermediate bus, the encryption is not decrypted and the watermark section 34 cannot be finally bypassed, so that unauthorized removal and tampering of the watermark can be prevented.

As shown in FIG. 36, the watermarked video signal 49 transmitted from the transmission section 46 of the retransmission device 28 on the system operator side as described above is received by the receiver 50 on the user side. . Receiver 50
In the case where the data is descrambled by the second descrambler 51 and compressed,
The data is expanded by the decoder 52 and output from the output unit 53 to the monitor 54 as a video signal 49a.

Next, the case of illegal copying will be described. The video signal 49a is recorded on the video tape 56 by the VTR 55, and a large number of illegally copied video tapes 56 appear on the world, infringing the copyright holder's rights.
However, when the BCA of the present invention is used, the video signal 49a
The video signal 49b reproduced from the video tape 56
(See FIG. 37) also has a watermark. Since the watermark is added in the frequency space, it cannot be easily erased. It does not disappear even through a normal recording and playback system.

Here, a method of detecting a watermark will be described with reference to FIG. Media 56 such as pirated video tapes and DVD laser disks are VT
The video signal 49b reproduced by a reproducing device 55a such as an R or DVD player is input to a first input unit 58 of a watermark detecting device 57, and is subjected to FFT or DCT.
And the like, a first spectrum 60 which is the spectrum of the illegally copied signal as shown in FIG. 35 (7) is obtained. On the other hand, the second input unit 58
The original original content 61 is input to a
The frequency is converted into the frequency axis by the frequency conversion unit 59a, and the second spectrum 35a is obtained. This spectrum is as shown in FIG. First spectrum 60
When the difference between the signal and the second spectrum 35a is calculated by the differentiator 62, a difference spectrum signal 63 as shown in FIG. 35 (8) is obtained. This difference spectrum signal 63 is input to the ID detection unit 64. The ID detection unit 64 extracts the ID = n-th watermark parameter from the ID database 22 (step 65), inputs the extracted parameter (step 65a), and compares the spectrum signal based on the watermark parameter with the difference spectrum signal 63. Is performed (step 65b). Next, it is determined whether or not the spectrum signal based on the watermark parameter matches the difference spectrum signal 63 (step 65c). If they match, it is determined that the watermark is ID = n, so it is determined that ID = n (step 65d). If they do not match, the ID
Is changed to (n + 1), the ID = (n + 1) th watermark parameter is extracted from the ID database 22, and the same steps are repeated to detect the watermark ID. If the ID is correct, the spectra match as shown in (3) and (8) of FIG.
Thus, the ID of the watermark is output from the output unit 66, and the source of the illegal copy is clarified.

As described above, the ID of the watermark
Since the source of the pirated disk or the illegally copied content can be tracked by specifying the URL, the copyright is protected.

A system combining a BCA and a watermark according to the present invention enables a ROM disk or RA
If the same video signal is recorded on the M disk and the watermark information is recorded on the BCA, a virtual watermark can be realized. As a result, the system operator uses the playback device of the present invention, and as a result, a watermark corresponding to the ID issued by the content provider is embedded in all video signals output from the playback device. Compared with the conventional method of recording video signals having different watermarks for each disc, disc cost and disc production time can be greatly reduced. The playback device requires a watermark circuit, but since FFT and IFFT are common, they do not impose a large burden on broadcast equipment.

Although the embodiment has been described using the watermark portion of the spread spectrum system, the same effect can be obtained by using another watermark system. DVD
In the case of the RAM disk 300 or the magneto-optical disk 240, the DVD recording / reproducing device shown in FIG.
In a content provider such as a CATV station having a magneto-optical recording / reproducing device shown in FIG. 1, encrypted scrambled data is transmitted from the content provider to another user via a communication line using the BCA ID number as one key. The data is sent to a reproducing apparatus and is once recorded on a DVD-RAM disk 300a or a magneto-optical disk 240a such as a CATV station. When reproducing from the same magneto-optical disk 240a on which the scramble signal is recorded, the BCA is read as shown in FIG.
Using the BCA data obtained from the BCA output unit 750 as a decryption key, the descrambling is performed by the descrambling unit, that is, the encryption decoder 534a. Then, the MPEG signal is expanded by the MPEG decoder 261 to obtain a video signal. However, the magneto-optical disk 240a of the normal usage is used.
When the scrambled data recorded on the disc is copied to another magneto-optical disc 240b, that is, when the scrambled data is illegally used, since the BCA data of the disc is different when reproduced, a correct decryption key for decrypting the scrambled data is obtained. The scramble is not released by the encryption decoder 534a. Therefore, no video signal is output. As described above, since the signal illegally copied to the second and subsequent magneto-optical disks 240b is not reproduced, the copyright is protected. As a result, the content can be recorded and reproduced on only one magneto-optical disk 240a. Similarly, in the case of the DVD-RAM disk 300a shown in FIG.
Recording and reproduction can be performed only on a single DVD-RAM disc.

Next, a stronger protection method will be described. First, the BCA data on the magneto-optical disk 240a on the user side is sent to the content provider side via a communication line. Next, on the content provider side, the BCA data is embedded as a watermark in the watermark recording unit 264 and transmitted. The user records this signal on the magneto-optical disk 240a. At the time of reproduction, the watermark reproduction collation unit 262 collates the recording permission identifier and the BCA data of the watermark with the BCA data obtained from the BCA output unit 750, and permits composite reproduction only when they match. This further enhances copyright protection. According to this method, even when digital / analog copying is performed directly from the magneto-optical disk 240a to the VTR tape, the watermark can be detected by the watermark reproducing unit 263, so that digital illegal copying can be prevented or detected. Similarly, in the case of the DVD-RAM disk 300a shown in FIG. 14, it is possible to prevent or detect illegal digital copying.

In this case, the magneto-optical recording / reproducing device or D
By providing the watermark reproducing unit 263 in the VD recording / reproducing apparatus, the recording is permitted by the recording preventing unit 265 only when the signal received from the content provider includes the watermark indicating the “one-time recordable identifier”. The recording prevention unit 265 and the “one-time recorded identifier” described later prevent recording on the second disk, that is, illegal copying.

The identifier indicating “recorded once” and the magneto-optical disk 24 recorded in the BCA recording unit 220 in advance.
0a is assigned to the watermark recording unit 2
According to 64, a secondary watermark is further superimposed and embedded in a recording signal containing the primary watermark, and is recorded on the magneto-optical disk 240a. Even if the data of the magneto-optical disk 240a is descrambled or converted to analog data once and recorded on another medium, for example, a VTR tape or a DVD-RAM, the VTR or the like is equipped with the watermark reproducing unit 263. For example, since the “one-time-recorded identifier” is detected, the recording of the second copy or the second copy is prevented by the unauthorized copy recording prevention unit 265, and the unauthorized copy is prevented. In the case of a VTR that is not equipped with the watermark reproducing unit 263, it is illegally copied. However, by examining the watermark of the illegally copied video tape later, the recording history information, for example, the recording data of the primary watermark such as the name of the content provider, and the BCA of the first legally recorded BCA. Since the secondary watermark in which the disc ID and the like are embedded can be reproduced, it is possible to track the content supplied from which content provider to which disk (who) on what month. Therefore, since the individual who committed the injustice can be specified, the individual can be caught by the Copyright Act, and the illegal copying of the same illegal actor and the planning of the same act can be indirectly prevented. Since the watermark does not disappear even if it is converted to an analog signal, this operation is
It is also effective in TR.

Even if a watermark indicating "recorded once" or "recording prohibited" is detected, a circuit for creating a detour or a scramble key is added, and recording or transmission is performed by an apparatus capable of illegal recording. The case will be described. In this case, it cannot be prevented directly, but the bypass circuit becomes very complicated. Further, as described above, since the recording progress can be specified by the primary watermark and the secondary watermark, it is possible to indirectly prevent unauthorized copying and unauthorized use as in the above case.

A specific effect of the BCA will be described.
Since the BCA data can identify the disc and the primary user of the content recorded in the database of the content provider from the data, the addition of the BCA enables tracing (tracking) of an unauthorized user when the watermark is used. Becomes easier.

Also, the recording circuit 2 shown in FIG.
As shown in FIG. 66, a part of the scrambled encryption key
By using the A data and using the BCA data as the primary watermark or the secondary watermark, if both are checked by the watermark reproducing unit 263 of the reproducing apparatus, illegal copying can be more strongly prevented.

Further, a key obtained by adding date information permitted by a system operator of a rental shop or the like to the watermark or scramble key from the time information input section 269 is given to the scramble section 271 or the password 271a.
To be synthesized. On the playback device side, the password 271a or BC
When the date information is reproduced and collated using the A data and the watermark, the encryption decoder 534a can limit the rescue period of the scramble key, for example, "can be used for three days". Such a rental disk system can also be used. In the case of the present invention, since it is protected by the above-described copy protection technology, copyright protection is strong, and illegal use becomes extremely difficult.

As described above, by using BCA for a rewritable optical disk such as a magneto-optical disk or DVD-RAM used for ASMO, copyright protection using a watermark or scramble is further enhanced. .

Further, in the above embodiment, the description has been made using the ROM disk, the RAM disk, or the optical disk having a single-plate structure of a two-layered DVD, but according to the present invention, regardless of the disk configuration. The same effect can be obtained over the entire disc. That is, other ROM disk, RAM disk, or DVD-R
Even if BCA is recorded on a disk or a magneto-optical disk, the same recording characteristics and reliability can be obtained. Each description is DV
The same effect can be obtained by replacing with a DR disk, DVD-RAM disk, or magneto-optical disk, but the description is omitted.

Since the BCA identification information in the above embodiment is for DVD and magneto-optical and has a common information signal format and the like, the optical head 255 for magneto-optical disk having the configuration shown in FIG. 7 is used. Thus, the BCA identification information for DVD can be reproduced. In this case, by adjusting the reproduction filter and the demodulation conditions at the time of signal reproduction, a reproduced signal of excellent BCA identification information with a small error rate can be obtained.

Also, in the magneto-optical disk of the above embodiment, since only the magnetic characteristics of the recording layer are changed, even in an environmental test, excellent reliability without oxidative deterioration of the recording layer and no change in mechanical characteristics is obtained. Property is obtained.

Further, in the above-described embodiment, a magneto-optical disk having a recording layer having a three-layer structure of the FAD system has been described as an example, but super-resolution reproduction of the RAD system, the CAD system, or the double mask system is performed. Even with a possible magneto-optical disk, identification information can be easily recorded by the recording method described in the above embodiment, so that content duplication can be prevented and the characteristics of the detection signal are excellent. It will be.

[0176]

As described above, according to the present invention,
The identification information (additional information) of the optical disk can be recorded and reproduced by a simple method, and the duplication of the content can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a magneto-optical disk according to an embodiment of the present invention.

FIG. 2 is a sectional view showing another configuration of the magneto-optical disk according to the embodiment of the present invention.

FIG. 3 is a diagram showing a principle of reproducing a magneto-optical disk according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a Kerr hysteresis loop in a direction perpendicular to the film surface of a heat-treated BCA portion and a non-heat-treated non-BCA portion of a recording layer of a magneto-optical disk according to an embodiment of the present invention. It is.

FIG. 5 is a diagram showing a relationship between a laser recording current for recording identification information of a magneto-optical disk and BCA recording characteristics according to the embodiment of the present invention.

FIG. 6A is a trace diagram showing a differential signal waveform of a BCA signal at a recording current of 8 A of the magneto-optical disk according to the embodiment of the present invention, and FIG. 6B is a trace diagram showing a waveform of the added signal. .

FIG. 7 is a diagram showing an optical configuration of a recording / reproducing apparatus for a magneto-optical disk according to an embodiment of the present invention.

FIG. 8 is a process chart showing a method for manufacturing a magneto-optical disk according to an embodiment of the present invention.

FIG. 9 is a process chart showing a method for recording identification information of a magneto-optical disk according to an embodiment of the present invention.

FIG. 10 is a configuration diagram showing an apparatus for checking BCA identification information of a magneto-optical disk according to an embodiment of the present invention.

FIG. 11A is a schematic diagram showing a state of a BCA section when identification information of a magneto-optical disk is recorded with an excessive recording power according to the embodiment of the present invention, and FIG. 11B is a diagram showing the embodiment of the present invention; FIG. 3 is a schematic diagram showing a state of a BCA section when the identification information of the magneto-optical disk in FIG.

FIG. 12A is a schematic diagram showing a result of observing a mark of a BCA portion with an optical microscope and a polarizing microscope when BCA identification information of a magneto-optical disk according to an embodiment of the present invention is recorded with an excessive recording power. And (b) is a schematic diagram showing the result of observing the mark of the BCA section with an optical microscope and a polarizing microscope when the BCA identification information of the magneto-optical disk according to the embodiment of the present invention is recorded at an optimum recording power.

FIG. 13A is a diagram illustrating a rotation angle of a polarization plane of a non-BCA portion of the magneto-optical disk according to the embodiment of the present invention;
FIG. 3B is a diagram illustrating a rotation angle of a polarization plane of a BCA portion of the magneto-optical disk according to the embodiment of the present invention.

FIG. 14 shows a DVD-ROM according to an embodiment of the present invention.
FIG. 1 is a block diagram showing a reproducing apparatus and a DVD recording / reproducing apparatus.

FIG. 15 is a block diagram illustrating a stripe recording apparatus according to an embodiment of the present invention.

FIG. 16 is a diagram illustrating a signal waveform and a trimming shape in the case of RZ recording according to the embodiment of the present invention.

FIG. 17 is a diagram showing signal waveforms and trimming shapes in the case of PE-RZ recording according to the embodiment of the present invention.

FIG. 18A is a perspective view showing a light condensing unit according to the embodiment of the present invention, and FIG. 18B is a diagram showing a stripe arrangement and a light emission pulse signal according to the embodiment of the present invention.

FIG. 19 is a diagram showing the arrangement of stripes on the magneto-optical disk and the contents of TOC data according to the embodiment of the present invention.

FIG. 20 is a diagram showing a flowchart for switching between CAV and CLV in stripe reproduction according to the embodiment of the present invention.

FIG. 21 (a) is an ECC according to the embodiment of the present invention.
FIG. 3B shows a data configuration after encoding, FIG. 4B shows a data configuration when n = 1 after ECC encoding according to the embodiment of the present invention, and FIG. 4C shows ECC error correction according to the embodiment of the present invention. It is a figure showing ability.

FIG. 22A is a diagram showing a data structure of a synchronization code;
(B) is a diagram showing a waveform of a fixed synchronization pattern, and (c) is a diagram showing a storage capacity.

23A is a configuration diagram of an LPF, and FIG. 23B is a waveform diagram after an LPF is added.

24A is a diagram illustrating a reproduced signal waveform diagram according to the embodiment of the present invention, and FIG. 24B is a diagram illustrating the dimensional accuracy of the stripe according to the embodiment of the present invention.

FIG. 25 is a diagram showing a procedure for reading and reproducing TOC data according to the embodiment of the present invention.

FIG. 26 is a block diagram showing a second level slice unit according to the embodiment of the present invention.

FIG. 27 is a waveform diagram of each part when the reproduction signal is binarized in the embodiment of the present invention.

FIG. 28 is a block diagram illustrating a specific circuit configuration of a second slice unit according to the embodiment of the present invention.

FIG. 29 is a block diagram showing a circuit configuration of a second level slice unit according to the embodiment of the present invention.

FIG. 30 is a block diagram illustrating a specific circuit configuration of a second level slice unit according to the embodiment of the present invention.

FIG. 31 is a diagram illustrating an actual signal waveform of each unit when the reproduction signal is binarized in the embodiment of the present invention.

FIG. 32 is a block diagram illustrating a disc manufacturing device of a content provider and a playback device of a system operator according to an embodiment of the present invention.

FIG. 33 is a block diagram showing a disk manufacturing unit in the disk manufacturing apparatus according to the embodiment of the present invention.

FIG. 34 is a block diagram illustrating an entire retransmission device and a playback device on the system operator side according to an embodiment of the present invention.

FIG. 35 is a diagram showing a waveform on the time axis and a waveform on the frequency axis of the original signal and each video signal in the embodiment of the present invention.

FIG. 36 is a block diagram illustrating a receiver on the user side and a retransmission device on the system operator side according to an embodiment of the present invention.

FIG. 37 is a block diagram illustrating a watermark detection device according to an embodiment of the present invention.

FIG. 38 is a cross-sectional view of trimming by a pulse laser according to an embodiment of the present invention.

FIG. 39 is a signal reproduction waveform diagram of a trimming unit according to the embodiment of the present invention.

FIG. 40 is a cross-sectional view illustrating a configuration of an optical disc according to an embodiment of the present invention.

FIG. 41 is a block diagram showing an optical disk recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 42 is a block diagram showing a recording / reproducing apparatus for a magneto-optical disk according to an embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 3 contents 4 MPEG encoder 5 master making machine 6 master 7 molding machine 8 substrate 9 bonding machine 10 bonding disk 11 BCA disk 12 identification code 13 BCA recorder 14 encryption encoder 15 reflection layer forming machine 16 BCA data 17 motor 18 BCA 19 disk Manufacturing unit 20 Encryption key 21 Disk manufacturing device 22 ID database 23 System operator 24 PE modulator 25 Reproduction device 26 ID generation unit 27 Watermark creation parameter generation unit 28 Retransmission device 29 Optical head 30 Data reproduction unit 31 Descrambler 32 Mutual authentication Unit 33 MPEG decoder 34 water mark unit 34a frequency conversion unit 35 frequency spectrum 36 spectrum mixing unit 37 inverse frequency conversion unit 38 ID number 39 BCA playback unit Reference Signs List 40 digital signature collation unit 41 IC card 42 output unit 43 MPEG encoder 44 encryption key (system operator) 45 second scrambler 46 transmission unit 47 compression parameter information 48 audio compression signal 49 video signal (with watermark) 50 receiver 51 2 descrambler 52 MPEG decoder 53 output unit 54 monitor 55 VTR 56 medium 57 watermark detection device 58 first input unit 59 first frequency conversion unit 60 first spectrum 61 original content 62 differentiator 63 difference spectrum signal 64 ID detection unit 65 Step 211, 231 Disk substrate 212, 232 Dielectric layer 213 Recording layer 214, 236 Intermediate dielectric layer 215, 237 Reflective layer 216, 238 Overcoat layer 217 Magnetizer 218 User 219 One-way converging lens 220 BCA section 221 BCA reader 222 Polarizer 223 Analyzer 224 Non-BCA section 225 Car hysteresis loop 226 BCA image 227 Rotation angle of reflected light 233 Reproduction magnetic film 234 Intermediate magnetic film 235 Recording magnetic film 584 Low Reflection unit 586 Low reflection light amount detection unit 587 Light amount level comparator 588 Light amount reference value 599 Low reflection unit start / end position detection unit 600 Low reflection unit position detection unit 601 Low reflection unit angle position signal output unit 602 Low reflection unit angle position detection Unit 605 Low-reflection start point 606 Low-reflection end point 607 Time delay correction unit 816 Disc manufacturing process 817 Secondary recording process 818 Step of disc manufacturing process 819 Step of secondary recording process 820 Step of first software production 830 Encoding Means 831 Public key system encryption 833 First secret key 834 Second secret key 835 Synthesizing unit 836 Recording circuit 837 Error correction encoding unit 838 Reed-Solomon encoding unit 839 Interleave unit 840 Pulse interval modulation unit 841 Clock signal unit 908 Serial number generation unit 909 Input unit 910 PE -RZ modulator 913 Clock signal generator 915 Motor 915a Rotation sensor 916 Second slice level 917 Cylindrical lens 918 Mask 919 Focusing lens 920 First time slot 921 Second time slot 922 Third time slot 923 Stripe 924 Pulse 925 First recording Area 926 Second recording area 927 ECC encoder 928 ECC decoder 929 Laser power supply circuit 931 Optical deflector 932 Slit 933 Stripe 934 Secondary scan Life 935 Deflection signal generator 936 TOC area 937 Stripe presence / absence identifier 938 Additional stripe presence / absence identifier 939 Additional stripe presence / absence identifier 940 Step (of flowchart for reproducing stripe presence / absence identifier) 941 (Pinhole) optical marking 942 PE-RZ demodulator 943 LPF 944 Address area 945 Main beam 946 Sub beam 948 Stripe backside existence identifier 949 Stripe blank portion 950 Scanning means 951 Data row 952 ECC row 953 Edge interval detection means 954 Comparison means 954 Memory means 957 Oscillator 957 Controller 958 Motor drive circuit 959 Bar code reading Means 963 Mode switch 964 Head moving means 965 Frequency comparator 966 Oscillator 967 Frequency ratio Vessel 968 oscillator 969 motor

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 13/00 G11B 13/00 20/10 20/10 H

Claims (76)

[Claims] 1. An optical disk having at least a recording layer made of a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface on a disk substrate, wherein a first recording area and a second recording area are provided in a specific portion of the recording layer. The additional recording information formed by the recording area, wherein the magnetic anisotropy of the second recording area in the direction perpendicular to the film surface is smaller than the magnetic anisotropy of the first recording area in the direction perpendicular to the film surface; An optical disk, wherein a recording area is formed as a stripe-shaped mark long in a disk radial direction, and a plurality of the marks are arranged in a disk circumferential direction based on a modulation signal of the additional information. 2. The optical disk according to claim 1, further comprising an identifier indicating whether or not a plurality of mark rows are arranged in a circumferential direction of the disk. 3. The optical disc according to claim 2, wherein an identifier indicating presence / absence of a mark string is recorded in the control data. 4. The optical disk according to claim 1, wherein the specific portion having the additional recording information is an inner peripheral portion of the disk. 5. The optical disc according to claim 1, wherein the difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area is equal to or less than a predetermined value. 6. The difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area is 10% or less.
An optical disk according to claim 1. 7. The optical disc according to claim 1, wherein a difference between an average refractive index of the first recording area and an average refractive index of the second recording area is 5% or less. 8. The optical disk according to claim 1, wherein the magnetic film in the second recording area is a magnetic film in which in-plane magnetic anisotropy is dominant. 9. The optical disk according to claim 1, wherein the magnetic film in the second recording area is a magnetic film at least partially crystallized. 10. The optical disk according to claim 1, wherein the recording layer comprises a plurality of stacked magnetic films. 11. An optical disc comprising at least a recording layer made of a thin film capable of reversibly changing between two optically detectable states on a disc substrate, wherein a specific portion of the recording layer has The recording medium further includes additional recording information formed by a first recording area and a second recording area, wherein the amount of reflected light from the first recording area and the amount of reflected light from the second recording area are different, and the second recording area is located in the disk radial direction. An optical disc, wherein the mark is formed as a long stripe-shaped mark, and a plurality of the marks are arranged in a circumferential direction of the disc based on a modulation signal of the additional information. 12. The optical disk according to claim 11, further comprising an identifier indicating presence / absence of a plurality of mark rows arranged in a circumferential direction of the disk. 13. The optical disc according to claim 12, wherein an identifier indicating presence / absence of a mark string is recorded in the control data. 14. The optical disk according to claim 11, wherein the specific portion having the additional recording information is an inner peripheral portion of the disk. 15. The optical disk according to claim 11, wherein the recording layer reversibly changes phase between a crystalline phase and an amorphous phase in accordance with the irradiation condition of the irradiated light. 16. The optical disc according to claim 15, wherein the difference between the amount of reflected light from the first recording area and the amount of reflected light from the second recording area is 10% or more. 17. The optical disc according to claim 15, wherein a difference between an average refractive index of the first recording area and an average refractive index of the second recording area is 5% or more. 18. The optical disc according to claim 15, wherein the second recording area of the recording layer has a crystalline phase. 19. The optical disc according to claim 15, wherein the recording layer is made of a Ge—Sb—Te alloy. 20. An optical disc in which main information is recorded, additional write information different for each disc is recorded, and at least a watermark creation parameter for creating a watermark is recorded in the additional information. 21. The optical disk according to claim 20, wherein main information is recorded by providing the concave and convex bits on the reflective film, and additional information is recorded by partially removing the reflective film. 22. The optical disk according to claim 20, wherein the main information and the additional information are recorded by partially changing the reflectance of the recording layer. 23. Main information is recorded by partially changing the direction of magnetization of a recording layer composed of a magnetic film having a magnetic anisotropy in a direction perpendicular to the film surface, and the main magnetic information is partially recorded. 21. The optical disc according to claim 20, wherein the write-once information is recorded by changing the optical disc. 24. At least a recording layer made of a magnetic film having magnetic anisotropy in a direction perpendicular to a film surface is provided on a disk substrate, and a first recording area and a second recording area are provided in a specific portion of the recording layer. A method of recording additional information on an optical disk having additional information formed by the method, wherein the specific layer of the recording layer is irradiated with a laser beam in the circumferential direction of the disk based on a modulation signal of the additional information, The second recording area is formed such that the magnetic anisotropy in the direction perpendicular to the film surface of the second recording area is smaller than the magnetic anisotropy in the direction perpendicular to the film surface of the first recording area.
A method for recording additional recording information on an optical disk, wherein a plurality of recording areas are formed in the disk circumferential direction as stripe-shaped marks long in the disk radial direction. 25. The optical disc according to claim 24, wherein, when forming the second recording area, the laser light source is caused to emit a pulse and the optical disc or the laser light is rotated based on a modulation signal of the phase-encoded write-once information. The method of recording additional information. 26. The apparatus further comprising a reflective layer and a protective layer on the disk substrate, wherein at least one of the disk substrate, the reflective layer and the protective layer is destroyed by the intensity of the laser beam applied to form the second recording area. 25. The method for recording additional recording information on an optical disk according to claim 24, wherein the intensity is lower than the intensity of the laser light to be written. 27. The method according to claim 24, wherein the intensity of the laser beam applied for forming the second recording area is an intensity for crystallizing at least a part of the recording layer. 28. The recording method of an optical disc according to claim 24, wherein the intensity of the laser light irradiated to form the second recording area is higher than the intensity of the laser light reaching the Curie temperature of the recording layer. . 29. The intensity of the laser beam applied to form the second recording area is an intensity that changes the magnetic film in the first recording area into a magnetic film in which in-plane magnetic anisotropy is dominant. 25. The method for recording additional recording information on an optical disk according to claim 24. 30. The method according to claim 24, wherein a one-way converging lens is used to irradiate a rectangular stripe-shaped laser beam onto the recording layer when forming the second recording area. 31. The method for recording additional recording information on an optical disk according to claim 24, wherein the light source of the laser light emitted to form the second recording area is a YAG laser. 32. When irradiating a laser beam from a YAG laser, a magnetic field of a predetermined value or more is applied to the recording layer.
Recording method of the additional recording information of the optical disk described in the above. 33. The method according to claim 32, wherein the magnetic field applied to the recording layer is 5 kOe or more. 34. At least a recording layer made of a thin film that can change reversibly between two optically detectable states on a disk substrate, and a first recording area is provided in a specific portion of the recording layer. A method of recording additional information on an optical disc having additional information formed by a second recording area and a second recording area,
By irradiating a laser beam in the disk circumferential direction of the specific portion of the recording layer based on the modulation signal of the additional information,
The second recording area is set so that the amount of reflected light from the first recording area and the amount of reflected light from the second recording area are different.
A method for recording additional recording information on an optical disk, wherein a plurality of stripe-shaped marks long in the disk radial direction are formed in the disk circumferential direction. 35. The optical disk according to claim 34, wherein when forming the second recording area, the laser light source is caused to emit a pulse and the optical disk or the laser light is rotated based on a modulation signal of the phase-encoded additional recording information. The method of recording additional information. 36. A disk substrate further comprising a reflective layer and a protective layer, wherein at least one of the disk substrate, the reflective layer and the protective layer is destroyed by the intensity of the laser light applied to form the second recording area. 35. The method for recording additional information on an optical disk according to claim 34, wherein the intensity is lower than the intensity of the laser light to be written. 37. The method according to claim 34, wherein the intensity of the laser beam applied for forming the second recording area is an intensity for crystallizing at least a part of the recording layer. 38. The method of recording additional recording information on an optical disk according to claim 34, wherein, when forming the second recording area, a one-way converging lens is used to irradiate the recording layer with a laser light having a rectangular stripe shape. 39. The method according to claim 35, wherein the light source of the laser light emitted to form the second recording area is a YAG laser. 40. A method for recording additional recording information on an optical disk, wherein a watermark is created based on a disk ID, and the watermark is superimposed on specific data and recorded as additional recording information. 41. At least a recording layer made of a magnetic film having magnetic anisotropy in a direction perpendicular to a film surface is provided on a disk substrate, and a specific portion of the recording layer has magnetic anisotropy in a direction perpendicular to the film surface. A method for reproducing write-once information of an optical disk provided with write-once information formed by different first recording areas and second recording areas, wherein linearly polarized laser light is incident on the specific portion, and reflected light from the optical disk is reflected. Alternatively, a method for reproducing additional information on an optical disk, wherein the additional information is reproduced by detecting a change in rotation of a polarization direction of transmitted light. 42. A method in which a magnetic field larger than the coercive force of the recording layer is applied to the specific portion to collectively magnetize the recording layer of the specific portion, and then linearly polarized laser light is incident on the specific portion. The method for reproducing the additional recording information of the optical disk according to the above. 43. Applying a unidirectional magnetic field to the specific portion while irradiating the specific portion with a certain amount of laser light to raise the temperature of the recording layer of the specific portion to the Curie temperature or higher. 5. After the direction of magnetization of the recording layer is aligned in one direction, linearly polarized laser light is incident on the specific portion.
2. The method for reproducing additional information of an optical disc according to item 1. 44. A disc substrate having at least a recording layer made of a thin film capable of reversibly changing between two optically detectable states, and a specific portion of the recording layer having a different reflectance. A method of reproducing additional information on an optical disk having additional information formed by a first recording area and a second recording area, the method comprising irradiating a laser beam condensed on the specific portion with a change in the amount of reflected light. A method for reproducing additional information on an optical disk, wherein the additional information is reproduced by detecting the additional information. 45. A main information recording area in which a signal of main information is recorded, and a sub-signal which is provided so as to overlap a part of the main information recording area and is phase-encoded and modulated is provided in the main information signal. An optical disc reproducing apparatus comprising a sub signal recording area recorded in a superimposed manner, wherein a means for performing a rotation phase control on the optical disc and reproducing a signal of the main information in the main information recording area by an optical head. First demodulating means for demodulating the main information signal to obtain main information data; and providing the mixed signal obtained by mixing the main information signal and the sub signal in the sub signal recording area to the optical head. Means for reproducing as a reproduction signal, a frequency separation means for suppressing the signal of the main information in the reproduction signal to obtain the sub signal, and a second method for obtaining the sub data by phase encoding and demodulating the sub signal. An optical disc reproducing device comprising a demodulating means. 46. The frequency separating means is a low frequency component separating means which obtains a low frequency reproduced signal by suppressing a high frequency component from a reproduced signal reproduced by the optical head, and further comprises a second frequency dividing means for converting a second signal from the low frequency reproduced signal. A second slice level setting unit for generating a slice level; and a second level slicer for slicing the low-frequency reproduction signal at the second slice level to obtain a binary signal, wherein the binary signal is phase-encoded. 46. Demodulation to obtain sub data
An optical disk reproducing apparatus according to claim 1. 47. A sub-low frequency component separating means having a larger time constant than the low frequency component separating means is provided in the second slice level setting unit, and the sub-low frequency component separating means reproduces the data reproduced by the optical head. 47. The optical disk reproduction according to claim 46, wherein a signal or a low frequency reproduction signal obtained by the low frequency component separation means is input, and a component having a lower frequency than the low frequency reproduction signal is extracted to obtain a second slice level. apparatus. 48. Frequency conversion means for converting a signal of main information in a reproduction signal reproduced by an optical head from a time axis signal to a frequency axis signal to create a first conversion signal, and 46. The apparatus according to claim 45, further comprising: means for generating a mixed signal in which information is added or superimposed; and inverse frequency converting means for converting the mixed signal from a frequency axis signal to a time axis signal to generate a second converted signal. Optical disk playback device. 49. An optical disk, wherein linearly polarized light is incident on an optical disk using an optical head, and transmitted light or reflected light from the optical disk is detected as a change in rotation of a polarization direction according to a recording signal of the optical disk. A reproducing device for moving the optical head to a specific portion of the optical disc on which additional information is recorded as necessary, and detecting transmitted light or reflected light from the specific portion as a change in rotation of a polarization direction. Means for reproducing the write-once information. 50. Additional information from control data based on a detection signal from detection light received by at least one light receiving element of the optical head or a sum signal of detection signals from detection light received by a plurality of the light receiving elements. Means for detecting an identifier indicating the presence / absence of the optical disc is further provided. When the identifier is detected and the presence of the additional information is confirmed, the identification unit of the optical disc on which the additional information is recorded as necessary. 50. The optical head is moved to the next position.
An optical disk reproducing apparatus according to claim 1. 51. The optical disk reproducing apparatus according to claim 49, further comprising a demodulating means for performing phase encoding demodulation when reproducing the additional recording information. 52. An optical disc reproducing apparatus in which main information is recorded and additional recording information different for each disc is recorded, wherein a signal reproducing section for reproducing the main information, and reproducing the additional recording information. An optical disc reproducing apparatus, comprising: a write-once information reproducing unit; and a watermark adding unit for generating a watermark signal based on the write-once information and outputting the watermark signal in addition to the main information. 53. The optical disk reproducing apparatus according to claim 52, wherein the additional recording information is recorded by partially changing a reflectance of a recording layer of the optical disk. 54. A recording layer of an optical disk, comprising a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, wherein additional information is recorded by partially changing the magnetic anisotropy perpendicular to the film surface. Item 53. The optical disk reproducing apparatus according to Item 52. 55. The optical disk reproducing apparatus according to claim 52, wherein the watermark adding section superimposes the sub information including the watermark on the signal of the main information. 56. A frequency conversion means for converting a signal of main information from a time axis signal to a frequency axis signal to generate a first converted signal, and generating a mixed signal obtained by adding or superimposing additional information on the first converted signal. 53. The optical disk reproducing apparatus according to claim 52, further comprising: means for converting the mixed signal from a frequency axis signal to a time axis signal to generate a second converted signal. 57. MPEG for expanding main information into a video signal
53. The optical disc reproducing apparatus according to claim 52, further comprising: a decoder; and means for inputting the video signal to a watermark adding unit. 58. A watermark reproducing unit for reproducing a watermark is further provided, and a mutual authentication unit is provided in both the MPEG decoder and the watermark reproducing unit to transmit encrypted main information and authenticate each other. 58. The optical disk reproducing apparatus according to claim 57, wherein the decryption is performed only when the two are satisfied. 59. A composite signal obtained by combining main information with an encryption decoder is input to an MPEG decoder.
An optical disk reproducing apparatus according to claim 1. 60. A watermark reproducing unit for reproducing a watermark is further provided, and a mutual authentication unit is provided in both the encryption decoder and the watermark reproducing unit to transmit encrypted main information and authenticate each other. 60. The optical disk reproducing apparatus according to claim 59, wherein the decryption is performed only when the two are satisfied. 61. An optical disc recording / reproducing apparatus for recording main information using a recording circuit and an optical head in a main recording area of a recording layer of an optical disk capable of recording, erasing, and reproducing information. Means for reproducing the additional information recorded in the specific part of the optical head by detecting the change in the rotation of the polarization plane by a signal output unit of the optical head, and using the additional information, the encryption information encrypted by an encryption encoder, Means for recording the main information in a main recording area, means for reproducing the additional information by a signal output unit of the optical head, and means for reproducing the main information by decrypting the encrypted information as a decryption key in an encryption decoder. An optical disk recording / reproducing apparatus comprising: 62. A main recording area of a recording layer of an optical disc,
An optical disc recording / reproducing apparatus for recording main information using a recording circuit and an optical head, further comprising a watermark adding unit for adding a watermark to the main information, wherein additional recording information recorded in a specific part of the recording layer Reproduced by the optical head, the reproduced additional information is added to the main information as a watermark by the watermark adding unit, the main information with the watermark is recorded in the main recording area, Recording / reproducing apparatus for optical discs. 63. The optical disk recording / reproducing apparatus according to claim 62, wherein the main information is recorded by partially changing the reflectance of the recording layer. 64. The recording layer according to claim 62, wherein the recording layer is formed of a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and main information is recorded by partially changing a direction of magnetization of the magnetic film. Optical disk recording and reproducing device. 65. Main information and additional recording information are reproduced by detecting a change in the direction of magnetization of the recording layer or a change in the magnitude of the perpendicular magnetic anisotropy of the recording layer as a change in the rotation of the polarization plane by an optical head. 65. The optical disk recording / reproducing apparatus according to claim 64. 66. The optical disk recording / reproducing apparatus according to claim 62, wherein the watermark adding section superimposes the sub information including the watermark on the signal of the main information. 67. A frequency conversion means for converting a signal of main information from a time axis signal to a frequency axis signal to create a first converted signal, and creating a mixed signal obtained by adding or superimposing additional information on the first converted signal. 63. The optical disc recording / reproducing apparatus according to claim 62, further comprising: means for converting the mixed signal from a frequency axis signal to a time axis signal to generate a second converted signal. 68. MPEG for expanding main information into a video signal
63. The optical disc recording / reproducing apparatus according to claim 62, further comprising: a decoder; and means for inputting the video signal to the watermark adding unit. 69. A watermark reproducing unit for reproducing a watermark, and a mutual authentication unit is provided in both the MPEG decoder and the watermark reproducing unit to transmit encrypted main information and authenticate each other. 69. The optical disk recording / reproducing apparatus according to claim 68, wherein the decryption is performed only when the two are satisfied. 70. A composite signal obtained by combining main information with an encryption decoder is input to an MPEG decoder.
An optical disk recording / reproducing apparatus according to claim 1. 71. A watermark reproducing unit for reproducing a watermark is further provided, and a mutual authentication unit is provided in both the encryption decoder and the watermark reproducing unit to transmit encrypted main information and authenticate each other. 71. The optical disk recording / reproducing apparatus according to claim 70, wherein the encryption is decrypted only when the two are satisfied. 72. An apparatus for recording additional information on an optical disk for recording additional information on an optical disk on which main information is recorded, comprising means for recording auxiliary information including at least one of a disk ID and a watermark creation parameter. An apparatus for recording additional recording information on an optical disc, characterized in that: 73. The optical disk according to claim 72, wherein the main information is recorded by providing concave and convex pits on a reflection film of the optical disk, and the sub information is recorded by partially removing the reflection film. Information recording device. 74. The main information is recorded by partially changing the reflectivity of the recording layer of the optical disc, and the sub information is recorded by partially changing the reflectivity of the recording layer. 72. An apparatus for recording additional information on an optical disk according to 72. 75. A recording layer of an optical disk, comprising a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, wherein main information is recorded by partially changing the direction of magnetization of the magnetic film, 73. The recording apparatus of an optical disc according to claim 72, wherein the information is recorded by partially changing the perpendicular magnetic anisotropy of the film surface. 76. A recording device for an optical disk on which main information is recorded, wherein a unit for creating a watermark based on sub-information including a disk ID, and a unit for recording data in which the watermark is superimposed on specific data An optical disk recording device comprising: