JP4264612B2 - Optical recording medium and reproducing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical recording medium and a recording / reproducing method thereof, and more particularly to an optical recording medium to which unique identification information that is difficult to duplicate or forge is added and a recording / reproducing method thereof.
[0002]
[Prior art]
In recent years, with the spread of personal computers and the Internet, the use of image data and audio data has increased, and the amount of digital data recorded on a recording medium has increased rapidly. As means for supplying or transferring enormous digital data, in addition to information communication using a cable such as a telephone line, information communication using a satellite and the like have been put into practical use one after another.
However, on the other hand, for example, since the supply of digital data via an optical recording medium such as an optical disk or a magneto-optical disk is relatively easy and low cost, the amount of circulation of the optical recording medium is rapidly increasing. Accordingly, the density and capacity of optical recording media have been rapidly increased, and large capacity optical recording media such as digital video disks have been put into practical use one after another for recording media for reproduction only. .
[0003]
As a conventional optical recording medium, for example, by transferring a pattern from a master stamper, an irregularity is formed on the surface when forming a substrate to form a recording layer, and when reproducing recorded information, the irregularity on the surface is detected by light irradiation. And a read-only optical recording medium. Further, there is a phase change recording / reproducing optical recording medium in which a phase change phenomenon is caused by light irradiation, a recording layer is formed using a material whose complex refractive index changes, and recording / reproduction is performed by light irradiation. Alternatively, a recording layer is formed using a material whose magnetization state changes due to light irradiation and application of a magnetic field, and a change in the magnetization state generated in the recording layer during recording of information is detected as a change in polarization state due to light irradiation. A magneto-optical recording / reproducing optical recording medium for reproducing information can be used.
[0004]
The above-described conventional optical recording medium can technically be forged for the reproduction itself, the phase change recording / reproducing system, and the magneto-optical recording / reproducing system. An information recording area is provided on the medium, but unique identification information that is difficult to copy is not added to the medium itself. Usually, in addition to digital data, information is added to an optical recording medium by printing on the surface of the medium. Such processing can be duplicated or forged. Therefore, there is a need for means for preventing illegal copying or forgery of optical recording media.
[0005]
As conventional means for preventing illegal duplication of an optical recording medium, for example, a method of using a part of recording information as unique identification information of the medium, or a digital watermark for embedding unique identification information in the recording information There are methods. For example, when reading information recorded on an optical recording medium, the user is required to input a password, a serial number, or the like to be checked against unique identification information on the optical recording medium. If the user input matches the unique identification information on the optical recording medium, reading of the information recorded on the optical recording medium is continued. If the user input does not match the unique identification information on the optical recording medium, reading of the information recorded on the optical recording medium is interrupted.
[0006]
[Problems to be solved by the invention]
However, according to the method of including the unique identification information in a part of the recorded information as described above, the recording / reproducing means of the recorded information and the unique identification information are the same. Information is also replicated. Therefore, if the user enters the same password or serial number as the original optical recording medium at the stage when the user is asked for the unique identification information, the copied optical recording medium can be used illegally. there were. Also, a method for reliably verifying whether the medium itself is a forged medium has not been developed.
[0007]
Furthermore, it is necessary that the unique identification information can be added to the medium itself relatively easily. For example, in the case of a read-only optical recording medium, the unevenness formed on the substrate surface when the substrate is formed becomes the recording layer. A plastic substrate often used as a substrate is formed by injecting a heat-melted resin at a high speed, filling a mold with a stamper, and then cooling. Therefore, if a recording layer that is uneven on the surface of the substrate is used to add unique identification information for each medium, it is necessary to change the stamper for each medium, which is difficult to put into practical use in terms of cost.
[0008]
The present invention has been made in view of the above problems. Therefore, the present invention provides an optical recording medium in which unique identification information that is difficult to duplicate or forge is added to the medium itself, and a recording / reproducing method thereof. For the purpose.
[0009]
[Means for Solving the Problems]
  In order to achieve the above object, the optical recording medium of the present invention comprises:A light transmissive substrate, a recording layer formed on one surface of the substrate, a reflective film formed on the surface of the recording layer, and a unique layer formed on the other surface of the substrate on which light is incident An identification information printing layer, and the unique identification information printing layer has a plurality of unique identification information recording areas respectively divided in a radial direction and a rotation direction of the optical recording medium. Each of the areas is a printing area or a non-printing area, the light transmittance of the printing area and the non-printing area is different, and unique identification information that can be reproduced is represented by the distribution of the printing area and the non-printing area.It is characterized by that.
[0010]
  The optical recording medium of the present invention preferably hasThe print area is a print area having a texture with a specific frequency.It is characterized by that. The optical recording medium of the present invention preferably has a protective film on the surface of the reflective film.
[0011]
  Alternatively, the optical recording medium of the present invention is preferably the recording medium.layerIs made of a material that undergoes a phase change phenomenon upon irradiation with light and changes its complex refractive index.Phase change recording layerIt is characterized by that. Alternatively, the optical recording medium of the present invention is preferably the recording medium.layerIs made of a material that changes its magnetization state by light irradiation and magnetic field application and can detect the change of the magnetization state as a change of polarization state.It is a magneto-optical recording filmIt is characterized by that. Alternatively, the optical recording medium of the present invention is preferably the recording medium.layerIsDepending on the presence or absence of dataIt contains an organic dye whose maximum absorption wavelength changes upon irradiation.
[0012]
This makes it possible to add unique identification information that is difficult to duplicate or forge to the optical recording medium. By collating the unique identification information recorded on the optical recording medium of the present invention, it becomes possible to prevent unauthorized duplication or forgery of the optical recording medium.
[0013]
  In order to achieve the above object, the optical recording medium of the present invention comprises:A light-transmitting substrate, a recording layer formed on one surface of the substrate, a reflective film that transmits part of the light formed on the surface of the recording layer, and formed on the surface of the reflective film A protective film, and a unique identification information printing layer formed on the surface of the protective film, wherein the unique identification information printing layer is divided into a plurality of radial and rotational directions of the optical recording medium, respectively. Having a unique identification information recording area,  Each of the unique identification information recording areas is a printing area or a non-printing area, the light reflectance of the printing area and the non-printing area is different, and a unique identification that can be reproduced by the distribution of the printing area and the non-printing area. Information is representedIt is characterized by that.
[0014]
  The optical recording medium of the present invention preferably hasThe print area is a print area having a texture with a specific frequency.It is characterized by that. The optical recording medium of the present invention is preferably the above-mentionedprintingThe region passes through the reflective film and isUnique identifierIt is a region that reflects the light incident on the print layer with a predetermined reflectance.
[0015]
  Alternatively, the optical recording medium of the present invention is preferably the recording medium.layerIs made of a material that undergoes a phase change phenomenon upon irradiation with light and changes its complex refractive index.Phase change recording layerIt is characterized by that. Alternatively, the optical recording medium of the present invention is preferably the recording medium.layerIs made of a material that changes its magnetization state by light irradiation and application of a magnetic field, and can detect the change of the magnetization state as a change of polarization state.It is a magneto-optical recording filmIt is characterized by that. Alternatively, the optical recording medium of the present invention is preferably the recording medium.layerIsDepending on the presence or absence of dataIt contains an organic dye whose maximum absorption wavelength changes upon irradiation.
[0016]
This makes it possible to add unique identification information that is difficult to duplicate or forge to the optical recording medium. By collating the unique identification information recorded on the optical recording medium of the present invention, it becomes possible to prevent unauthorized duplication or forgery of the optical recording medium.
[0017]
  In order to achieve the above object, an optical recording medium reproducing method of the present invention is an optical recording medium reproducing method for reproducing recorded information by irradiating light,Irradiating the unique identification information printing layer with light, detecting a distribution of a printing region and a non-printing region having different light transmittances, irradiating the recording layer with the light, and irradiating the light Is divided into a low-frequency part and a high-frequency part, the unique identification information of the optical recording medium is reproduced from the low-frequency part signal, and the recording information of the optical recording medium is reproduced from the high-frequency part signal. And a step of collating the reproduced unique identification information with the unique identification information registered in advance in the host after the step of reproducing and the step of reproducing the unique identification information. A process of reproducing information is performedIt is characterized by that.
[0019]
  Recording of optical recording medium of the present inventionOf informationPlayback methodIn, PreferablyThe printing area is a printing area having a texture with a specific frequency. Preferably, the recording layer is a recording surface on which irregularities are formed according to the presence or absence of data. More preferably, a protective film is provided on the surface of the reflective film.Alternatively, preferablyThe recording layer is a phase change recording layer made of a material that undergoes a phase change phenomenon upon irradiation with light and changes a complex refractive index.It is characterized by that.
[0020]
  Alternatively, the recording of the optical recording medium of the present inventionOf informationPlayback methodIn, PreferablyThe recording layer is a magneto-optical recording film made of a material whose magnetization state is changed by light irradiation and application of a magnetic field, and which can detect the change in the magnetization state as a change in the polarization state.It is characterized by that. Alternatively, preferablyThe recording layer contains an organic dye whose maximum absorption wavelength is changed by irradiation of recording light depending on the presence or absence of data.It is characterized by that.
[0021]
  Recording of optical recording medium of the present inventionOf informationPreferably, in the reproducing method, the step of reproducing the unique identification information and the recorded information includes irradiating the light andUnique identifierRecord the transmitted light through the printing layerlayerIncident on the recording medium and the recordinglayerAnd a step of reflecting the reflected light from the reflection film and a step of detecting the reflection light from the reflection film.
[0022]
This makes it possible to add unique identification information that is difficult to duplicate or counterfeit to an optical recording medium that records and reproduces information. By managing the unique identification information on the optical recording medium, it is possible to prevent unauthorized copying or forgery of the optical recording medium.
[0023]
  In order to achieve the above object, an optical recording medium reproducing method of the present invention is an optical recording medium reproducing method for reproducing recorded information by irradiating light,Irradiating the unique identification information printing layer with light, detecting a distribution of a printing region and a non-printing region having different reflectances of the light, irradiating the recording layer with the light, and irradiating the light Is divided into a low-frequency part and a high-frequency part, the unique identification information of the optical recording medium is reproduced from the low-frequency part signal, and the recording information of the optical recording medium is reproduced from the high-frequency part signal. And a step of collating the reproduced unique identification information with the unique identification information registered in advance in the host after the step of reproducing and the step of reproducing the unique identification information. A process of reproducing information is performedIt is characterized by that.
[0025]
  Recording of optical recording medium of the present inventionOf informationPlayback methodIn, PreferablyThe printing area is a printing area having a texture with a specific frequency. Preferably, the recording layer is a recording surface on which irregularities are formed according to the presence or absence of data.Alternatively, preferablyThe recording layer is a phase change recording layer made of a material that undergoes a phase change phenomenon upon irradiation with light and changes a complex refractive index.It is characterized by that.
[0026]
  Alternatively, the recording of the optical recording medium of the present inventionOf informationPlayback methodIn, PreferablyThe recording layer is a magneto-optical recording film made of a material whose magnetization state is changed by light irradiation and application of a magnetic field, and which can detect the change in the magnetization state as a change in the polarization state.It is characterized by that. Alternatively, preferablyThe recording layer contains an organic dye whose maximum absorption wavelength is changed by irradiation of recording light depending on the presence or absence of data.It is characterized by that.
[0027]
  Recording of optical recording medium of the present inventionOf informationIn the reproducing method, preferably, the step of reproducing the unique identification information and the recording information includes irradiating the light with the recording.layerA step of reflecting the transmitted light of the reflective film by the reflective film;Unique identifierA step of reflecting by a printed layer, the reflective film and theUnique identifierAnd a step of detecting reflected light from the printed layer.
[0028]
This makes it possible to add unique identification information that is difficult to duplicate or counterfeit to an optical recording medium that records and reproduces information. By managing the unique identification information on the optical recording medium, it is possible to prevent unauthorized copying or forgery of the optical recording medium.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an optical recording medium and a recording / reproducing method thereof according to the present invention will be described below with reference to the drawings.
(Embodiment 1)
1 and 2 are sectional views of the optical recording medium (optical disk) of this embodiment, and FIG. 3 is a top view thereof. As shown in FIG. 1, a laser beam (reproducing light) L is irradiated onto a recording surface 2 through a light-transmitting substrate 1. The light reflected by the reflective film 3 is detected, and the recorded information is read out. A unique identification information printing layer 4 is formed on the surface of the substrate 1 opposite to the recording surface 2.
[0030]
FIG. 2 is a more detailed cross-sectional view of FIG. 1. As shown in FIG. 2, the optical disk of this embodiment has a recording surface 2 with irregularities formed on one surface of the substrate 1. The substrate 1 is made of an acrylic resin such as polycarbonate or polymethyl methacrylate, and has a film thickness of about 1.2 mm, for example. On the surface of the recording surface 2, for example, a reflective film 3 on which Al or an Al alloy is deposited is formed. As the material of the reflective film 3, materials other than metals can be used as long as they have a predetermined reflectance at the wavelength of the reproduction light. Further, a protective film 5 made of an ultraviolet curable resin or the like is usually formed on the surface of the reflective film. A print area 4 a is formed on at least a part of the unique identification information print layer 4.
[0031]
As shown in FIG. 3, the unique identification information printing layer 4 has a plurality of unique identification information recording areas 4 'which are respectively divided in the radial direction and the rotation direction (circumferential direction) of the optical disc. FIG. 3 schematically shows the case of the unique identification information printing layer 4 having a total of 24 unique identification information recording areas 4 ′ divided into three in the radial direction of the optical disk and eight in the rotation direction. The division pattern of the identification information recording area 4 ′ is not limited to this. In addition, the unique identification information recording area 4 ′ is not necessarily formed on the entire surface of the optical disc. The unique identification information recording area 4 ′ is either a semi-transmissive printing area 4 a or a non-printing area 4 b that partially transmits light.
[0032]
As shown in FIGS. 1 and 2, in the case of the configuration in which the reproducing light is irradiated onto the recording surface 2 through the substrate 1, the transmittance of the reproducing light through the substrate 1 is usually designed to be almost 100%. However, according to the optical recording medium of the present embodiment, the transmittance of the reproduction light in the print region 4a is, for example, about 95%, and a difference from the transmittance in the non-print region 4b is provided. As a result, the distribution of the print area 4a and the non-print area 4b can be detected as a change in the envelope of the reproduction signal. When the laser beam is focused on the recording surface 2, a change in transmittance is superimposed on the reproduction signal intensity in the print area 4a of the unique identification information recording area 4 '.
[0033]
4A and 4B schematically show how to read the unique identification information from the optical recording medium shown in FIGS. If the arbitrary position of the optical recording medium shown in FIG. 3 is 0 degree, the unique identification information recording area 4 ′ (printing area 4a and non-printing area 4b) in the reproduction beam paths A, B, and C, which are mutually different in the radial direction, are used. The distribution is expressed as shown in FIG. FIG. 4B shows the reproduction signal intensity in the reproduction beam path A. As shown in FIG. 4B, the reproduction signal is detected as a high frequency having a constant amplitude. However, the signal on the recording surface is modulated in the print area 4a and other portions, and the envelope changes as a low cycle. The print area 4a is detected.
[0034]
(Embodiment 2)
5 and 6 are sectional views of the optical recording medium (optical disk) of this embodiment. The optical disc of the present embodiment has a layer configuration different from that of the optical disc of the first embodiment, and the top view is the same as that of the first embodiment (see FIG. 3).
As shown in FIG. 5, the laser beam (reproduction light) L is applied to the recording surface 2 through the light-transmitting substrate 1. The light reflected by the reflective film 3 is detected and the recorded information is read out, but a part of the laser light L passes through the reflective film 3. In particular, when the reflective film is thin, the transmittance of the reflective film increases to some extent. In the optical disc of this embodiment, the unique identification information printing layer 4 is formed on the surface opposite to the light incident side of the substrate 1, and the transmitted light of the reflective film 3 is used to make a print area and a non-print area. Identification is performed.
[0035]
FIG. 6 is a more detailed cross-sectional view of FIG. 5. As shown in FIG. 6, the optical disk of this embodiment has a recording surface 2 with irregularities formed on one surface of the substrate 1. The substrate 1 is made of polycarbonate, for example, and the film thickness is about 1.2 mm, for example. On the surface of the recording surface 2, for example, a reflective film 3 on which Al is deposited is formed. Further, a protective film 5 made of an ultraviolet curable resin or the like is usually formed on the surface of the reflective film. Further, the unique identification information print layer 4 is formed on the surface of the protective film 5, and the print region 4 a is formed on at least a part of the unique identification information print layer 4.
[0036]
According to the optical recording medium of the present embodiment, the unique identification information printing layer 4 is formed using a material having a certain degree of reflectance with respect to the laser light. As a result, the distribution of the print area 4a and the non-print area 4b can be detected as a change in the envelope of the reproduction signal. When the laser beam is focused on the recording surface 2, the intensity of the reflected light from the optical disk changes in the print area 4a in the unique identification information recording area 4 'and is superimposed on the reproduction signal intensity.
[0037]
(Embodiment 3)
FIG. 7 shows a top view of the optical recording medium (optical disk) of the present embodiment. In the first or second embodiment, the unique identification information print area 4a is formed as a uniform print surface as shown in the top view of FIG. 3, but the unique identification information is printed as shown in FIG. You may form the printing surface which has a texture of a specific frequency as the area | region 4c.
As shown in the first embodiment, when a uniform printing surface is formed, there is a possibility that dirt such as a fingerprint adhering to the surface of the optical recording medium is erroneously detected as the printing area 4a of the unique identification information. On the other hand, according to the optical recording medium of this embodiment, the specific frequency of the texture formed on the printing surface is reflected in the reproduction signal. Therefore, it is possible to more easily discriminate between the stain on the surface of the optical recording medium and the print area 4c of the unique identification information.
[0038]
(Embodiment 4)
FIG. 8 is a block diagram showing an example of a reproducing apparatus that can be used for reproducing the optical recording medium of the present invention. The reproduction apparatus of FIG. 8 includes an optical pickup 11, an amplifier circuit 12, a matrix circuit 13, a phase compensation circuit 14, a biaxial drive circuit 15, and a band dividing unit 16. The optical recording medium 17 is rotated at a constant linear velocity or angular velocity by a motor 18.
[0039]
The optical pickup 11 includes a laser diode 21, a collimator lens 22, a diffraction grating 23, a polarization beam splitter 24, an objective lens 25, a condenser lens 26, and a photodiode 27. The optical pickup 11 is also provided with an electromagnetic actuator (not shown) that moves the laser diode 21, the objective lens 25, and the like. Although not shown, a ½ wavelength plate is provided between the diffraction grating 23 and the polarizing beam splitter 24, and a ¼ wavelength plate is provided between the polarizing beam splitter 24 and the objective lens 25.
[0040]
The optical pickup 11 irradiates the optical recording medium 17 with the laser light L from the laser diode 21, detects the reflected light from the optical recording medium 17 with the photodiode 27, and generates a light reception signal.
In the optical pickup 11, the laser diode 21 emits linearly polarized laser light L, and the laser light L enters the diffraction grating 23 as parallel light by the collimator lens 22. The laser beam L is separated by the diffraction grating 23 into a main beam (0th order diffracted light) and a sub beam (first order diffracted light). Further, the polarization planes of the main beam and the sub beam are rotated by the half-wave plate. Most of the light from the half-wave plate is transmitted through the polarization beam splitter 24 and reaches the quarter-wave plate, and enters the objective lens 25 as circularly polarized light.
[0041]
The laser beam LB reflected by the optical recording medium 17 becomes linearly polarized light by the quarter wavelength plate and enters the polarization beam splitter 24. At this time, the plane of polarization is orthogonal to the light from the half-wave plate (light irradiated from the laser diode 21) and the light from the quarter-wave plate (reflected light from the optical recording medium 17). Thereafter, the laser beam L is reflected by the polarization beam splitter 24, converged by the condenser lens 26, and enters the photodiode 27. In the photodiode 27, the laser beam L is photoelectrically converted to generate a light reception signal.
[0042]
The amplifier circuit 12 converts the received light signal generated by the optical pickup 11 from a current signal to a voltage signal, amplifies the signal, and supplies the amplified signal to the matrix circuit 13. The matrix circuit 13 generates a reproduction signal RF, a focus error signal FE, and a tracking error signal TE based on the received light signal. The phase compensation circuit 14 compensates the focus error signal FE and the tracking error signal TE supplied from the matrix circuit 13 (phase compensation and / or frequency compensation), and supplies the compensation signal to the biaxial drive circuit 15.
[0043]
Based on the compensation signal from the phase compensation circuit 14, the biaxial drive circuit 15 generates a drive control signal for the electromagnetic actuator that moves the objective lens 25 and supplies the drive control signal to the optical pickup 11. The electromagnetic actuator in the optical pickup 11 has a focusing actuator and a tracking actuator, and the focusing actuator moves the objective lens in the focus direction based on the compensation signal of the focus error signal FE. On the other hand, the tracking actuator moves the objective lens in the tracking direction (radial direction of the optical recording medium 17) based on the compensation signal of the tracking error signal TE.
The motor 18 is constituted by, for example, a spindle motor.
[0044]
The reproduction signal RF supplied from the matrix circuit 13 is separated into a high frequency part and a low frequency part by a band dividing unit 16 including a band pass filter, for example. The recording information of the optical recording medium is detected from the high frequency part of the reproduction signal RF, and the unique identification information of the optical recording medium is detected from the low frequency part.
As described above, by adding the band dividing unit 16 to the conventional optical recording medium reproducing apparatus and providing means for analyzing the low frequency part of the reproduction signal RF, the recording information and the unique identification from the optical recording medium of the present invention are provided. Information can be reproduced.
[0045]
(Embodiment 5)
The flowchart of FIG. 9 shows a procedure for reproducing recorded information and unique identification information from the optical recording medium of the present invention.
As shown in FIG. 9, first, an optical recording medium (disc) is inserted into a reproducing apparatus, and then the focus is adjusted. When collating the unique identification information (ID) from the host, the radius R of the reproduction beam path A, B, C in FIG.₁, R₂, R_ThreeR = R₁Seek to the appropriate address and ID₁Is detected. Next, R = R₂Seek to the appropriate address and ID₂Is detected. Furthermore, R = R_ThreeSeek to the appropriate address and ID_ThreeIs detected. ID above₁, ID₂And ID_ThreeThe detection order can be changed as appropriate. When the detected ID is returned to the host and collated with the ID registered in advance in the host, the information recorded on the disk is read out and normal operation is started.
[0046]
On the other hand, when the ID is not collated from the host, the normal operation is started after the focus adjustment as in the conventional optical recording medium.
If an attempt is made to reproduce a disc on which recorded information is illegally copied or forged by the above-described optical recording medium reproduction procedure, normal operation cannot be performed unless the printed surface including the unique identification information is also duplicated or forged. . Since the addition of the unique identification information on the disc is performed by a method different from the recording of the recording information, the copying or forgery of the optical recording medium is more difficult than the copying or forgery of the conventional optical recording medium. It becomes difficult. Therefore, according to the optical recording medium of the present embodiment, it is possible to prevent unauthorized duplication or forgery of the optical recording medium, or use of an illegally duplicated or forged optical recording medium.
[0047]
(Embodiment 6)
The optical recording medium of the present invention is not limited to the read-only optical recording medium shown in the first and second embodiments, and may be an optical recording medium such as a phase change recording / reproducing method or a magneto-optical recording / reproducing method. In the case of an optical recording medium that is rewritable and uses light irradiation for information recording, as in the phase change recording / reproducing system or magneto-optical recording / reproducing system, the optical recording medium is similar to the first embodiment described above. When the unique identification information printing layer is formed on the surface, the laser light (recording light) irradiated at the time of recording information is affected by the unique identification information printing layer. Therefore, when the unique identification information printing layer is formed on these rewritable optical recording media, the printing layer is formed after the information is recorded.
[0048]
10A and 10B are cross-sectional views of the phase change recording / reproducing optical recording medium of the present embodiment. As shown in FIG. 10, the optical recording medium of this embodiment has a structure in which a substrate 1, a dielectric film 6, a phase change recording layer 7, a reflective film 3, and a protective film 5 are laminated in this order from the light incident side. As the material for the substrate 1, the reflective film 3, and the protective film 5, the same materials as those in the first embodiment can be used. As the dielectric film 6, for example, ZnS-SiO₂The dielectric film 6 functions as a protective film for the phase change recording layer 7. As the phase change recording layer 7, for example, a Ge—Sb—Te layer is used. As the material of the phase change recording layer 7, a material that reversibly changes phase between crystal and amorphous by laser light irradiation, for example, a chalcogen or a chalcogen compound is used.
[0049]
In the case of FIG. 10A, the unique identification information printing layer 4 is formed on the surface of the substrate 1 on which the laser beam is irradiated, and the reproduction light transmitted through the printing area is transmitted as in the first embodiment. The unique identification information is reproduced by utilizing the fact that the intensity is weaker than that of the reproduction light transmitted through the non-printing area.
On the other hand, in the case of FIG. 10B, the unique identification information printing layer 4 is formed on the surface of the protective film 5, and the reproduction light transmitted through the reflective film 3 is reflected by the unique identification information printing layer 4. The identification information is reproduced.
[0050]
FIGS. 11A and 11B are sectional views of an optical recording medium of the magneto-optical recording / reproducing system of this embodiment. As shown in FIG. 11, the optical recording medium of this embodiment has a structure in which a substrate 1, a dielectric film 6, a magneto-optical recording film 8, a reflective film 3 and a protective film 5 are laminated in this order from the light incident side. As materials for the substrate 1, the reflective film 3, and the protective film 5, the same materials as those in the first embodiment can be used. As the dielectric film 6, for example, ZnS-SiO₂The dielectric film 6 functions as a protective film for the magneto-optical recording film 8.
[0051]
As the magneto-optical recording film 8, for example, an amorphous alloy layer of TbFeCo is used. The magneto-optical recording film 8 can be made of a ferrite material, a permanent magnet material, or the like that changes its magnetization state when irradiated with laser light while a magnetic field is applied. In addition to the above-described TbFeCo layer, the magneto-optical recording film 8 is made of, for example, an amorphous alloy layer such as TbFe, GdFeCo, GdFe, NdFeCo, NdFe, DyFeCo, or DyFe, a multilayer film such as Co / Pt, or an oxide such as a garnet material. Layers can also be used.
[0052]
In the case of FIG. 11A, the unique identification information printing layer 4 is formed on the surface of the substrate 1 on which the laser beam is irradiated, and the reproduction light transmitted through the printing area is transmitted as in the first embodiment. The unique identification information is reproduced by utilizing the fact that the intensity is weaker than that of the reproduction light transmitted through the non-printing area.
On the other hand, in the case of FIG. 11B, the unique identification information printing layer 4 is formed on the surface of the protective film 5, and the reproduction light transmitted through the reflective film 3 is reflected by the unique identification information printing layer 4 to be unique. The identification information is reproduced.
[0053]
According to the optical recording medium of the above-described embodiment of the present invention, it is possible to prevent unauthorized duplication or forgery of the optical recording medium by providing the optical recording medium with a unique identification information printing layer that is difficult to duplicate or forge. it can.
In addition, according to the recording / reproducing method of the embodiment of the present invention, the unique identification information that is difficult to duplicate is added to the optical recording medium, the unique identification information on the optical recording medium is collated, and then the optical recording medium Since reproduction is performed, it becomes possible to prevent the use of an optical recording medium that has been illegally copied or forged.
[0054]
The embodiments of the optical recording medium and the recording / reproducing method thereof according to the present invention are not limited to the above description. For example, the optical recording medium is not limited to a disk type. The present invention can also be applied to optical recording media other than the above-described reproduction-only, phase change recording / reproducing system or magneto-optical recording / reproducing system. For example, the present invention can be applied to an optical recording medium that records information by changing the maximum absorption wavelength of the organic dye contained in the recording layer by irradiating recording light. Is possible. In addition, various modifications can be made without departing from the scope of the present invention.
[0055]
【The invention's effect】
According to the optical recording medium of the present invention, it is possible to add unique identification information that is difficult to duplicate or forge to each optical recording medium.
Further, according to the recording / reproducing method of the present invention, it is possible to reproduce the recorded information after collating the unique identification information recorded on the optical recording medium. It becomes possible to prevent use.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an optical recording medium according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view of an optical recording medium according to Embodiment 1 of the present invention.
FIG. 3 is a top view of the optical recording medium according to Embodiment 1 of the invention.
FIG. 4 is a schematic diagram showing a read signal from the optical recording medium according to the first embodiment of the invention.
FIG. 5 is a cross-sectional view of an optical recording medium according to Embodiment 2 of the present invention.
FIG. 6 is a cross-sectional view of an optical recording medium according to Embodiment 2 of the present invention.
FIG. 7 is a top view of an optical recording medium according to Embodiment 3 of the present invention.
FIG. 8 is a block diagram illustrating an optical recording medium reproducing device according to a fourth embodiment of the present invention.
FIG. 9 is a flowchart showing a reproducing procedure of the optical recording medium according to the fifth embodiment of the present invention.
10A and 10B are cross-sectional views of an optical recording medium according to Embodiment 6 of the present invention.
FIGS. 11A and 11B are cross-sectional views of an optical recording medium according to Embodiment 6 of the present invention.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Recording surface, 3 ... Reflective film, 4 ... Unique identification information printing layer, 4 '... Unique identification information recording area, 4a, 4c ... Printing area, 4b ... Non-printing area, 5 ...protectionFilm, 6 ... dielectric layer, 7 ... phase change recording layer, 8 ... magneto-optical recording film, 11 ... optical pickup, 12 ... amplifier circuit, 13 ... matrix circuit, 14 ... phase compensation circuit, 15 ... biaxial drive circuit, DESCRIPTION OF SYMBOLS 16 ... Band division part, 17 ... Optical recording medium, 18 ... Motor, 21 ... Laser diode, 22 ... Collimator lens, 23 ... Diffraction grating, 24 ... Polarizing beam splitter, 25 ... Objective lens, 26 ... Condensing lens, 27 ... Photodiode.

Claims (16)

An optical recording medium,
A light transmissive substrate;
A recording layer formed on one side of the substrate;
A reflective film formed on the surface of the recording layer;
A unique identification information printing layer formed on the other surface on which the light of the substrate is incident;
Have
The unique identification information printing layer has a plurality of unique identification information recording areas each divided in a radial direction and a rotation direction of the optical recording medium,
Each of the unique identification information recording areas is a printing area or a non-printing area, the light transmittance of the printing area and the non-printing area is different, and a unique identification that can be reproduced by the distribution of the printing area and the non-printing area. Information is represented,
The print area is a print area having a texture with a specific frequency.
Optical recording medium.   The optical recording medium according to claim 1, wherein the recording layer is a recording surface on which irregularities are formed according to the presence or absence of data.   The optical recording medium according to claim 1, further comprising a protective film on a surface of the reflective film.   The optical recording medium according to claim 1, wherein the recording layer is a phase change recording layer.   The optical recording medium according to claim 1, wherein the recording layer is a magneto-optical recording film.   The optical recording medium according to claim 1, wherein the recording layer contains an organic dye whose maximum absorption wavelength is changed by irradiation of recording light according to the presence or absence of data. An optical recording medium,
A light transmissive substrate;
A recording layer formed on one side of the substrate;
A reflective film that transmits part of the light formed on the surface of the recording layer;
A protective film formed on the surface of the reflective film;
A unique identification information printing layer formed on the surface of the protective film;
Have
The unique identification information printing layer has a plurality of unique identification information recording areas each divided in a radial direction and a rotation direction of the optical recording medium,
Each of the unique identification information recording areas is a printing area or a non-printing area, the light reflectance of the printing area and the non-printing area is different, and a unique identification that can be reproduced by the distribution of the printing area and the non-printing area. Information is represented,
Optical recording medium. The optical recording medium according to claim 7 , wherein the print area is a print area having a texture with a specific frequency. The optical recording medium according to claim 7 , wherein the recording layer is a recording surface on which irregularities are formed according to the presence or absence of data. The optical recording medium according to claim 7 , wherein the recording layer is a phase change recording layer. The optical recording medium according to claim 7 , wherein the recording layer is a magneto-optical recording film. The optical recording medium according to claim 7 , wherein the recording layer contains an organic dye whose maximum absorption wavelength is changed by irradiation of recording light according to the presence or absence of data. A method for reproducing recorded information of an optical recording medium according to any one of claims 1 to 6 ,
Irradiating the unique identification information printing layer with light, and detecting a distribution of printed areas and non-printed areas having different light transmittances;
Irradiating the recording layer with the light;
The reproduction signal obtained by the light irradiation is divided into a low band part and a high band part, the unique identification information of the optical recording medium is reproduced from the low band signal, and the optical recording medium is reproduced from the high band signal. Reproducing the recorded information of
After the step of reproducing the unique identification information, the step of collating the reproduced unique identification information with the unique identification information registered in advance in the host;
Have
When the collation is performed, a step of reproducing the recorded information is performed.
A method for reproducing an optical recording medium. The step of reproducing the unique identification information and the recorded information includes irradiating the light and causing the transmitted light of the unique identification information printing layer to enter the recording layer ;
Reflecting the transmitted light of the recording layer by a reflective film;
The method of reproducing an optical recording medium according to claim 13, further comprising a step of detecting reflected light from the reflective film. A method for reproducing recorded information of an optical recording medium according to any one of claims 7 to 12 ,
Irradiating the unique identification information printing layer with light, and detecting a distribution of printed areas and non-printed areas having different reflectances of the light;
Irradiating the recording layer with the light;
The reproduction signal obtained by the light irradiation is divided into a low band part and a high band part, the unique identification information of the optical recording medium is reproduced from the low band signal, and the optical recording medium is reproduced from the high band signal. Reproducing the recorded information of
After the step of reproducing the unique identification information, the step of collating the reproduced unique identification information with the unique identification information registered in advance in the host;
Have
When the collation is performed, a step of reproducing the recorded information is performed.
A method for reproducing an optical recording medium. The step of reproducing the unique identification information and the recording information includes the step of irradiating the light and reflecting the light transmitted through the recording layer by a reflection film;
Reflecting the transmitted light of the reflective film by the unique identification information printing layer;
The method for reproducing an optical recording medium according to claim 15 , further comprising a step of detecting reflected light from the reflective film and the unique identification information printing layer.

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