JP2001176132A - Optical recording medium and recording and reproducing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium to which the intrinsic identification information difficult to be duplicated or forged to the medium itself is added and a recording and reproducing method for the same. SOLUTION: The optical recording medium has recording regions for information, is subjected to the reproduction of the information by irradiation with light and has a printing layer 4 divided into the plural intrinsic identification information recording regions. The intrinsic identification information recording regions are respectively either of first regions allowing the transmission of part of the light at the prescribed transmittance and second region having the transmittance different from the transmittance of the first regions. Identification information intrinsic to the optical recording medium is displayed by the distribution of the first region and record region. The recording and reproducing method for the same is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium and a method for recording and reproducing the same, and more particularly, to an optical recording medium to which unique identification information that is difficult to copy or forge is added, and a method for recording and reproducing the same.

[0002]

2. Description of the Related 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 recording media has increased rapidly. As means for supplying or transferring a huge amount of 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. On the other hand, however, the supply of digital data via an optical recording medium such as an optical disk or a magneto-optical disk is relatively easy and at low cost, so that the distribution amount 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 discs have also been put into practical use as read-only recording media. .

As a conventional optical recording medium, for example, a pattern is transferred from a master stamper to form a recording layer by forming irregularities on the surface at the time of molding a substrate. At the time of reproducing recorded information, the surface is irradiated by light. There is a read-only optical recording medium for detecting unevenness. Further, there is an optical recording medium of a phase change recording / reproducing system in which a recording layer is formed by using a material which causes a phase change phenomenon by light irradiation to change a complex refractive index and performs recording / reproduction by light irradiation. Alternatively, a recording layer is formed using a material whose magnetization state changes by light irradiation and application of a magnetic field, and a change in the magnetization state generated in the recording layer during information recording is detected as a change in the polarization state by light irradiation, An optical recording medium of a magneto-optical recording / reproducing method for reproducing information is exemplified.

[0004] In the above-mentioned conventional optical recording medium, counterfeiting of the medium itself is technically possible in any of the read-only, phase change recording / reproducing system, and magneto-optical recording / reproducing system. Although a recording area for information is provided on the medium, unique identification information that is difficult to copy is not added to the medium itself. Usually, information is added to an optical recording medium by printing on the surface of the medium in addition to digital data, but such processing can be duplicated or counterfeited. Therefore, there is a need for a means for preventing unauthorized duplication or forgery of the optical recording medium.

As conventional means for preventing unauthorized 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 embedding unique identification information in the recording information. There are digital watermarking methods and the like. For example, when reading information recorded on an optical recording medium, the user is required to input a password, a serial number, and the like for collating with the unique identification information on the optical recording medium. If the user's input matches the unique identification information on the optical recording medium, the 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, the reading of the information recorded on the optical recording medium is interrupted.

[0006]

However, according to the method of including the unique identification information in a part of the recorded information as described above, since the recording / reproducing means for the recorded information and the unique identification information is the same, If the record information is copied illegally, the unique identification information is also copied. Therefore, if the same password or serial number as that of the optical recording medium from which the copy is made is input at the stage where the user inquires of the unique identification information, unauthorized use of the duplicated optical recording medium is possible. there were. Also, no method has been developed to reliably verify whether the medium itself is a forged medium.

[0007] Further, 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 during molding of the substrate becomes the recording layer. A plastic substrate frequently used as a substrate is formed by injecting a hot-melted resin at a high speed, filling a mold with a stamper, and then cooling. Therefore, if an attempt is made to add unique identification information for each medium by using a recording layer having irregularities on the substrate surface, it is necessary to change the stamper for each medium, and it is difficult to put it to practical use in terms of cost.

The present invention has been made in view of the above-mentioned problems, and accordingly, the present invention provides an optical recording medium in which unique identification information which is difficult to copy or forge is added to the medium itself, and a method for recording and reproducing the same. The purpose is to provide.

[0009]

In order to achieve the above-mentioned object, an optical recording medium according to the present invention has an information recording area and reproduces the information by irradiating light. A print layer divided into a plurality of unique identification information recording areas, wherein each of the unique identification information recording areas has a first area that transmits a part of the light at a predetermined transmittance; The ratio is any one of the second areas different from the first area, and identification information unique to the optical recording medium is represented by the distribution of the first area and the second area. The optical recording medium according to the present invention is preferably characterized in that the first area is a print area and the second area is a non-print area. In the optical recording medium according to the present invention, more preferably, the first area is a print area having a texture of a specific frequency.

[0010] The optical recording medium of the present invention preferably has a light transmissive substrate, and the recording area is formed on a first surface, which is one surface of the substrate, and is detected by the light irradiation. It is characterized by being a possible uneven portion. The optical recording medium of the present invention is further preferably formed on the first surface of the substrate,
It has a reflective film which reflects the light which enters into the substrate from the second surface which is the other surface of the substrate.
The optical recording medium of the present invention is preferably characterized in that the printing layer is a layer formed on the second surface of the substrate. The optical recording medium of the present invention preferably has a protective film on the surface of the reflective film.

Alternatively, in the optical recording medium of the present invention, preferably, the recording area causes a phase change phenomenon by light irradiation,
It is characterized by being made of a material whose complex refractive index changes.
Alternatively, in the optical recording medium of the present invention, preferably, the recording area is made of a material whose magnetization state changes 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. Alternatively, the optical recording medium of the present invention is preferably characterized in that the recording area contains an organic dye whose maximum absorption wavelength changes by light irradiation.

This makes it possible to add unique identification information that is difficult to copy or counterfeit to the optical recording medium. By collating the unique identification information recorded on the optical recording medium of the present invention, it is possible to prevent unauthorized duplication or forgery of the optical recording medium.

In order to achieve the above object, an optical recording medium according to the present invention has an information recording area, and reproduces the information by irradiating light. A print layer divided into information recording areas, wherein each of the unique identification information recording areas reflects a part of the light at a predetermined reflectance, and a reflectance of the light is the first area. And a distribution of the first area and the second area indicates identification information unique to the optical recording medium. The optical recording medium according to the present invention is preferably characterized in that the first area is a print area and the second area is a non-print area. In the optical recording medium according to the present invention, more preferably, the first area is a print area having a texture of a specific frequency.

The optical recording medium of the present invention preferably has a light-transmitting substrate, and the recording area is formed on a first surface, which is one surface of the substrate, and is detected by the light irradiation. It is characterized by being a possible uneven portion. More preferably, the optical recording medium of the present invention is a reflective film formed on a first surface of the substrate, and reflects the light incident on the substrate from a second surface, which is the other surface of the substrate. And a reflective film that transmits a part of the light. In the optical recording medium of the present invention, preferably, the printing layer is a layer formed on a surface of the reflective film via a protective film, and the first region is
It is a region that reflects the light incident on the printing layer through the reflective film at a predetermined reflectance.

Alternatively, in the optical recording medium of the present invention, preferably, the recording area causes a phase change phenomenon by light irradiation,
It is characterized by being made of a material whose complex refractive index changes.
Alternatively, the optical recording medium of the present invention is preferably such that the recording area is made of a material whose magnetization state changes 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. Features. Alternatively, the optical recording medium of the present invention is preferably characterized in that the recording area contains an organic dye whose maximum absorption wavelength changes by light irradiation.

This makes it possible to add unique identification information that is difficult to copy or counterfeit to the optical recording medium. By collating the unique identification information recorded on the optical recording medium of the present invention, it is possible to prevent unauthorized duplication or forgery of the optical recording medium.

In order to achieve the above object, a method for recording / reproducing an optical recording medium according to the present invention is a method for recording / reproducing an optical recording medium which has a recording area for information and reproduces recorded information by irradiating light. Recording information in the recording area; and forming, on one surface of the optical recording medium, a plurality of unique identification information recording areas each of which is one of a first area and a second area having a different light transmittance. Forming a print layer having, detecting the distribution of the first area and the second area by irradiating the print layer with the light, reproducing the unique identification information of the optical recording medium, Irradiating the recording area with light to reproduce the recorded information.

In the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of reproducing the unique identification information and the recorded information includes the steps of irradiating the recording area and the printing layer with the light; The reproduction signal obtained by light irradiation is divided into a low-frequency part and a high-frequency part, and the unique identification information of the optical recording medium is reproduced from the low-frequency part signal. Reproducing the recorded information. The recording / reproducing method of the optical recording medium of the present invention comprises:
Preferably, the step of forming the print layer includes a step of forming a print area in the first area and setting a non-print area as the second area.

In the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of recording information in the recording area comprises providing one surface with irregularities detectable by light irradiation, A step of forming a constituent substrate. Alternatively, the recording / reproducing method of the optical recording medium according to the present invention, preferably, the step of recording the information includes a step of causing a phase change phenomenon by irradiating the recording area with light to change a complex refractive index. Features.

Alternatively, in the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of recording the information includes a step of changing a magnetization state of the recording area by applying light and applying a magnetic field. The step of reproducing the recorded information includes irradiating the recording area with light and detecting a change in the magnetization state as a change in the polarization state. Alternatively, the recording / reproducing method of the optical recording medium of the present invention comprises:
Preferably, the step of recording the information includes a step of changing a maximum absorption wavelength of an organic dye contained in the recording area by light irradiation.

In the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of reproducing the unique identification information and the recorded information includes irradiating the light to transmit the transmitted light of the printing layer to the recording area. The method is characterized by including a step of causing light to enter, a step of reflecting light transmitted through the recording area by a reflective film, and a step of detecting reflected light from the reflective film.

This makes it possible to add unique identification information, which is difficult to copy or counterfeit, to an optical recording medium for recording / reproducing information. By managing the unique identification information on the optical recording medium, it is possible to prevent unauthorized duplication or forgery of the optical recording medium.

In order to achieve the above object, a method for recording / reproducing an optical recording medium according to the present invention is a method for recording / reproducing an optical recording medium which has a recording area for information and reproduces recorded information by irradiating light. Recording information in the recording area; and forming, on one surface of the optical recording medium, a plurality of unique identification information recording areas each of which is one of a first area and a second area having different light reflectivities. Forming a print layer having, detecting the distribution of the first area and the second area by irradiating the print layer with the light, reproducing the unique identification information of the optical recording medium, Irradiating the recording area with light to reproduce the recorded information.

In the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of reproducing the unique identification information and the recorded information includes irradiating the recording area and the printing layer with the light, The reproduction signal obtained by light irradiation is divided into a low-frequency part and a high-frequency part, and the unique identification information of the optical recording medium is reproduced from the low-frequency part signal. Reproducing the recorded information. The recording / reproducing method of the optical recording medium of the present invention comprises:
Preferably, the step of forming the print layer includes a step of forming a print area in the first area and setting a non-print area as the second area.

In the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of recording information in the recording area includes the step of providing irregularities detectable by light irradiation on one surface of the optical recording medium. A step of forming a constituent substrate. Alternatively, the recording / reproducing method of the optical recording medium according to the present invention, preferably, the step of recording the information includes a step of causing a phase change phenomenon by irradiating the recording area with light to change a complex refractive index. Features.

Alternatively, in the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of recording the information includes a step of changing a magnetization state of the recording region by applying light and applying a magnetic field. The step of reproducing the recorded information includes irradiating the recording area with light and detecting a change in the magnetization state as a change in the polarization state. Alternatively, the recording / reproducing method of the optical recording medium of the present invention comprises:
Preferably, the step of recording the information includes a step of changing a maximum absorption wavelength of an organic dye contained in the recording area by light irradiation.

In the recording / reproducing method for an optical recording medium according to the present invention, preferably, the step of reproducing the unique identification information and the recorded information includes irradiating the light and reflecting light transmitted through the recording area by a reflective film. And reflecting the light transmitted through the reflective film by the print layer, and detecting the reflected light from the reflective film and the print layer.

This makes it possible to add unique identification information that is difficult to copy or counterfeit to an optical recording medium on which information is recorded / reproduced. By managing the unique identification information on the optical recording medium, it is possible to prevent unauthorized duplication or forgery of the optical recording medium.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the optical recording medium and the recording / reproducing method of the present invention will be described below with reference to the drawings. (Embodiment 1) FIGS. 1 and 2 are sectional views of an optical recording medium (optical disc) of the present embodiment, and FIG. 3 is a top view thereof. As shown in FIG. 1, a recording surface 2 is irradiated with a laser beam (reproducing light) L via a light transmitting substrate 1. Reflective film 3
, The reflected light is detected, and the recorded information is read. A unique identification information printing layer 4 is formed on the surface of the substrate 1 opposite to the recording surface 2.

FIG. 2 is a more detailed sectional view of FIG.
As shown in FIG. 2, the optical disc of the present embodiment has a recording surface 2 in which irregularities are formed on one surface of a substrate 1. The substrate 1 is made of, for example, an acrylic resin such as polycarbonate or polymethyl methacrylate, and has a thickness of, for example, 1.2.
mm. On the surface of the recording surface 2, a reflective film 3 on which, for example, Al or an Al alloy is deposited is formed. As a material of the reflection film 3, any material other than metal can be used as long as it has a predetermined reflectance at the wavelength of the reproduction light. On the surface of the reflective film, a protective film 5 usually made of an ultraviolet curable resin or the like is formed. A print area 4 a is formed in at least a part of the unique identification information print layer 4.

As shown in FIG. 3, the unique identification information printing layer 4 has a radial direction and a rotational direction (circumferential direction) of the optical disk.
And has a plurality of unique identification information recording areas 4 ', each of which is divided into FIG. 3 schematically shows a 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 disc and divided into eight in the rotation direction. The division pattern of the identification information recording area 4 'is not limited to this. Also, the unique identification information recording area 4 'need not necessarily be formed on the entire surface of the optical disc. The unique identification information recording area 4 'is either a semi-transparent print area 4a that partially transmits light or a non-print area 4b.

As shown in FIGS. 1 and 2, in the case of a configuration in which the reproduction light is irradiated onto the recording surface 2 through the substrate 1, the transmittance of the reproduction light on the substrate 1 is usually designed to be approximately 100%. Is done. However, according to the optical recording medium of the present embodiment, the transmittance of the reproduction light in the print area 4a is set to, for example, about 95%, and the difference from the transmittance in the non-print area 4b is provided. Thereby, the print area 4a and the non-print area 4
The distribution of b can be detected as a change in the envelope of the reproduction signal. When the laser light is focused on the recording surface 2,
In the print area 4a of the unique identification information recording area 4 ', a change in transmittance is superimposed on the reproduction signal intensity.

FIGS. 4A and 4B schematically show reading of the unique identification information from the optical recording medium shown in FIGS. An arbitrary position on the optical recording medium shown in FIG.
In FIG. 4A, the distribution of the unique identification information recording area 4 ′ (printed area 4a and non-printed area 4b) in the reproduction beam paths A, B, and C different in the radial direction is shown in FIG.
It is represented as FIG. 4B shows the reproduction signal intensity in the reproduction beam path A. As shown in FIG. 4 (b), the reproduced signal is detected as a high frequency having a constant amplitude, but the modulation of the signal on the recording surface occurs in the print area 4a and other parts, and as a change in the low cycle of the envelope, The print area 4a is detected.

(Embodiment 2) FIGS. 5 and 6 are cross-sectional views of an optical recording medium (optical disk) of the present embodiment. The optical disc of the present embodiment has a different layer configuration from the optical disc of the first embodiment, and the top view is common to the first embodiment (see FIG. 3). As shown in FIG. 5, a laser light (reproducing light) L is applied to a recording surface 2 via a light transmitting substrate 1. The light reflected by the reflective film 3 is detected, and the recorded information is read out. A part of the laser light L passes through the reflective film 3. In particular, when the thickness of the reflective film is small, the transmittance of the reflective film is increased to some extent. The optical disc of this embodiment has a unique identification information printing layer 4 on the surface of the substrate 1 opposite to the light incident side.
Are formed, and the printed area and the non-printed area are identified using the light transmitted through the reflective film 3.

FIG. 6 is a more detailed sectional view of FIG.
As shown in FIG. 6, the optical disc of the present embodiment has a recording surface 2 in which irregularities are formed on one surface of a substrate 1. The substrate 1 is made of, for example, polycarbonate, and has a thickness of, for example, about 1.2 mm. On the surface of the recording surface 2, for example, A
The reflective film 3 on which 1 is deposited is formed. On the surface of the reflective film, a protective film 5 usually made of an ultraviolet curable resin or the like is formed. Further, the unique identification information printing layer 4 is formed on the surface of the protective film 5, and the unique identification information printing layer 4 is formed.
The print area 4a is formed in at least a part of.

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 reflectivity to laser light. Thereby, the printing area 4
a and the distribution of the non-printing area 4b can be detected as a change in the envelope of the reproduction signal. When the laser light is focused on the recording surface 2, the intensity of the light reflected from the optical disc changes in the printing area 4a of the unique identification information recording area 4 ',
Superimposed on the reproduction signal strength.

(Embodiment 3) FIG. 7 shows a top view of an optical recording medium (optical disc) of the present embodiment. In the first or second embodiment, the printing area 4a of the unique identification information is formed as a uniform printing surface as shown in the top view of FIG. 3, but the printing of the unique identification information is performed as shown in FIG. Area 4c
Alternatively, a printing surface having a texture of a specific frequency may be formed. As described in the first embodiment, when a uniform printing surface is formed, there is a possibility that a stain such as a fingerprint attached to the surface of the optical recording medium is erroneously detected as the printing region 4a of the unique identification information. On the other hand, according to the optical recording medium of the present 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 determine the dirt on the surface of the optical recording medium and the print area 4c of the unique identification information.

(Embodiment 4) FIG. 8 is a block diagram showing an example of a reproducing apparatus which can be used for reproducing the optical recording medium of the present invention. The reproducing apparatus shown in FIG.
It has an amplifier circuit 12, a matrix circuit 13, a phase compensation circuit 14, a two-axis drive circuit 15, and a band division unit 16. The optical recording medium 17 is rotated at a constant linear velocity or angular velocity by a motor 18.

The optical pickup 11 has a laser diode 2
1, a collimator lens 22, a diffraction grating 23, a polarizing 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) for moving the laser diode 21, the objective lens 25, and the like. Although not shown, a 波長 wavelength plate is provided between the diffraction grating 23 and the polarization beam splitter 24, and a 波長 wavelength plate is provided between the polarization beam splitter 24 and the objective lens 25.

The optical pickup 11 irradiates the laser beam L from the laser diode 21 to the optical recording medium 17 and detects the reflected light from the optical recording medium 17 by the photodiode 27 to generate a light receiving signal. In the optical pickup 11, the laser diode 21 emits linearly polarized laser light L, and the laser light L is converted into parallel light by the collimator lens 22 and enters the diffraction grating 23. 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 passes through the polarization beam splitter 24, reaches the quarter-wave plate, and enters the objective lens 25 as circularly polarized light.

The laser beam LB reflected on the optical recording medium 17 becomes linearly polarized light by a 波長 wavelength plate, and enters the polarization beam splitter 24. At this time, 1/2
Light from wave plate (irradiation light from laser diode 21)
The light from the quarter-wave plate (reflected light from the optical recording medium 17) is orthogonal to the plane of polarization. After that, the laser beam L is reflected by the polarization beam splitter 24 and
The light is converged by 6 and enters the photodiode 27.
The laser light L is photoelectrically converted in the photodiode 27 to generate a light receiving signal.

The amplification circuit 12 converts the light reception 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. Matrix circuit 1
3 generates a reproduction signal RF, a focus error signal FE, and a tracking error signal TE based on the light receiving 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 a compensation signal to the two-axis drive circuit 15.

The biaxial drive circuit 15 generates a drive control signal for an electromagnetic actuator for moving the objective lens 25 based on the compensation signal from the phase compensation circuit 14 and supplies the 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 a compensation signal of the focus error signal FE. On the other hand, the tracking actuator generates the tracking error signal TE.
The objective lens is moved in the tracking direction (radial direction of the optical recording medium 17) based on the compensation signal of (1). Motor 1
8 is constituted by, for example, a spindle motor.

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. Playback signal R
The recording information of the optical recording medium is detected from the high-frequency part of F, and the unique identification information of the optical recording medium is detected from the low-frequency part. As described above, the band division unit 16 is used in the conventional optical recording medium reproducing apparatus.
Is added, and the means for analyzing the low-frequency portion of the reproduction signal RF is provided, whereby the recorded information and the unique identification information can be reproduced from the optical recording medium of the present invention.

(Embodiment 5) A procedure for reproducing recorded information and unique identification information from an optical recording medium according to the present invention is shown in the flowchart of FIG. As shown in FIG. 9, first, the optical recording medium (disk) is inserted into the reproducing apparatus, and then the focus is adjusted. When the host performs collation of the unique identification information (ID), the radii R of the reproduction beam paths A, B, and C in FIG. 3 or FIG. 7 are set as R ₁ , R ₂ , and R ₃ , respectively, and R = R ₁ . to detect the ID ₁ to seek to address. Next, ID and seek to R = R ₂ corresponds addresses
Detect ₂ Furthermore, to detect the ID ₃ that seeking R = R ₃ equivalent address. The detection order of ID ₁ , ID ₂ and ID ₃ can be changed as appropriate. When the detected ID is returned to the host and compared with the ID registered in the host in advance, the information recorded on the disc is read, and the normal operation is started.

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. By the above-described optical recording medium reproducing procedure, when trying to reproduce a disk in which the recorded information is illegally duplicated or forged, a normal operation cannot be performed unless the printed surface including the unique identification information is also duplicated or forged. . The addition of the unique identification information on the disc is performed by a different method from the recording of the recording information, so the duplication or forgery of the optical recording medium is more effective than the duplication or forgery of the conventional optical recording medium. It will be 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 optical recording medium that is illegally duplicated or forged.

(Embodiment 6) The optical recording medium of the present invention is not limited to the read-only optical recording medium shown in Embodiments 1 and 2, but may be an optical recording medium such as a phase change recording / reproducing method or a magneto-optical recording / reproducing method. It may be. In the case of an optical recording medium that is rewritable and uses light irradiation for recording information, such as a phase change recording / reproducing method or a magneto-optical recording / reproducing method, the optical recording medium is When the unique identification information printing layer is formed on the surface, the laser light (recording light) irradiated when recording information is affected by the unique identification information printing layer. Therefore, when forming a unique identification information printing layer on these rewritable optical recording media, the printing layer is formed after recording information.

FIGS. 10A and 10B are cross-sectional views of an optical recording medium of the phase change recording / reproducing method according to the present embodiment. FIG.
As shown in FIG. 1, the optical recording medium of the present 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 sequentially stacked from the light incident side. As the material of the substrate 1, the reflective film 3, and the protective film 5, the same materials as those in the first embodiment can be used. For example, a ZnS—SiO ₂ layer is used as the dielectric film 6, and the dielectric film 6 functions as a protective film for the phase change recording layer 7. For example, a Ge—Sb—Te layer is used as the phase change recording layer 7. As the material of the phase change recording layer 7, a material that reversibly changes phase between a crystal and an amorphous by irradiation with a laser beam, for example, a chalcogen or a chalcogen compound is used.

In the case of FIG. 10 (a), the unique identification information printing layer 4 is formed on the surface of the substrate 1 on the side irradiated with the laser beam, and transmits through the printing area as in the first embodiment. The reproduction of the unique identification information is performed by utilizing the fact that the intensity of the reproduction light is lower 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 reflection film 3 is reflected by the unique identification information printing layer 4, and Reproduction of the identification information is performed.

FIGS. 11A and 11B are cross-sectional views of the magneto-optical recording / reproducing optical recording medium of the present embodiment. FIG.
As shown in FIG. 1, the optical recording medium of the present 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 sequentially stacked from the light incident side. As the material of 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, a ZnS—SiO ₂ layer is used, and the dielectric film 6 functions as a protective film for the magneto-optical recording film 8.

As the magneto-optical recording film 8, for example, TbFeC
An amorphous alloy layer of o is used. Magneto-optical recording film 8
For example, a ferrite material or a permanent magnet material whose magnetization state changes by irradiating a laser beam with a magnetic field applied thereto can be used. As the magneto-optical recording film 8, other than the above-described TbFeCo layer, for example, TbFe, GdFeC
o, GdFe, NdFeCo, NdFe, DyFeC
An amorphous alloy layer such as o or DyFe, a multilayer film such as Co / Pt, or a layer made of an oxide such as a garnet material can also be used.

In the case of FIG. 11A, the unique identification information printing layer 4 is formed on the surface of the substrate 1 on the side irradiated with the laser beam, and transmits through the printing area as in the first embodiment. The reproduction of the unique identification information is performed by utilizing the fact that the intensity of the reproduction light is lower 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 reflection film 3 is reflected by the unique identification information printing layer 4, and Reproduction of the identification information is performed.

According to the optical recording medium of the above-described embodiment of the present invention, by providing the optical recording medium with a unique identification information printing layer that is difficult to duplicate or forge, illegal copy or forgery of the optical recording medium can be prevented. can do. According to the recording / reproducing method of the embodiment of the present invention described above, unique identification information that is difficult to copy is added to the optical recording medium, and the unique identification information on the optical recording medium is collated. Since the reproduction is performed, it is possible to prevent the use of an optical recording medium that has been illegally copied or forged.

Embodiments of the optical recording medium and the recording / reproducing method of the present invention are not limited to the above description. For example,
The optical recording medium is not limited to a disk type. Further, the present invention can be applied to an optical recording medium other than the above-mentioned read-only, phase-change recording / reproducing method or magneto-optical recording / reproducing method. For example, the present invention can be applied to an optical recording medium of a type that records information by changing the maximum absorption wavelength of the organic dye contained in the recording layer by irradiating the recording light, and adding the unique identification information. It is possible. In addition, various changes can be made without departing from the gist of the present invention.

[0055]

According to the optical recording medium of the present invention, it is possible to add unique identification information which is difficult to copy 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, and to reproduce the illegally duplicated or forged optical recording medium. Use can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical recording medium according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view of the optical recording medium according to the first embodiment of the present invention.

FIG. 3 is a top view of the optical recording medium according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a read signal from the optical recording medium according to the first embodiment of the present invention.

FIG. 5 is a sectional view of an optical recording medium according to Embodiment 2 of the present invention.

FIG. 6 is a 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 a reproducing apparatus for an optical recording medium according to a fourth embodiment of the present invention.

FIG. 9 is a flowchart showing a reproducing procedure of the optical recording medium of the present invention according to the fifth embodiment of the present invention.

FIGS. 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 ... reflection film, 4 ... unique identification information printing layer, 4 '... unique identification information recording area, 4a, 4c ... printing area, 4b ... non-printing area, 5 ... reflection film, 6 ... dielectric layer, 7 ... phase change recording layer, 8 ... magneto-optical recording film, 11 ... optical pickup, 12 ... amplifying circuit, 13 ... matrix circuit,
14: phase compensation circuit, 15: biaxial drive circuit, 16: band splitting unit, 17: optical recording medium, 18: motor, 21: laser diode, 22: collimator lens, 23: diffraction grating, 24: polarization beam splitter, 25 ... objective lens,
26: condenser lens, 27: photodiode.

Claims (35)

[Claims] 1. An optical recording medium having an information recording area and reproducing the information by irradiating light, comprising: a printing layer divided into a plurality of unique identification information recording areas; Each of the unique identification information recording areas is one of a first area that transmits a part of the light at a predetermined transmittance, and a second area that has a different transmittance of the light from the first area. An optical recording medium in which identification information unique to the optical recording medium is represented by a distribution of one area and the second area. 2. The method according to claim 1, wherein the first area is a print area, and the second area is a print area.
The optical recording medium according to claim 1, wherein the area is a non-print area. 3. The optical recording medium according to claim 2, wherein the first area is a print area having a texture of a specific frequency. 4. A recording medium according to claim 1, further comprising a light-transmitting substrate, wherein said recording area is an uneven portion formed on a first surface, which is one surface of said substrate, which can be detected by irradiating said light. Optical recording medium. 5. The optical recording medium according to claim 4, further comprising a reflection film formed on the first surface of the substrate and reflecting the light incident on the substrate from a second surface, which is the other surface of the substrate. 6. The optical recording medium according to claim 5, wherein said printing layer is a layer formed on a second surface of said substrate. 7. The optical recording medium according to claim 6, further comprising a protective film on a surface of said reflection film. 8. The recording area according to claim 1, wherein the recording area is made of a material which undergoes a phase change phenomenon by light irradiation and changes in complex refractive index.
The optical recording medium according to the above. 9. The optical recording medium according to claim 1, wherein said recording area is made of a material whose magnetization state changes by light irradiation and application of a magnetic field, and which can detect said change in said magnetization state as a change in polarization state. 10. The optical recording medium according to claim 1, wherein said recording area contains an organic dye whose maximum absorption wavelength changes by light irradiation. 11. An optical recording medium having an information recording area and reproducing the information by irradiating light, comprising: a printing layer divided into a plurality of unique identification information recording areas; Each of the unique identification information recording areas is one of a first area that reflects a part of the light at a predetermined reflectance, and a second area that has a different reflectance from the first area, and An optical recording medium in which identification information unique to the optical recording medium is represented by a distribution of one area and the second area. 12. The recording medium according to claim 11, wherein said first area is a print area, and said second area is a non-print area. 13. The optical recording medium according to claim 12, wherein said first area is a print area having a texture of a specific frequency. 14. A recording medium according to claim 11, further comprising a light-transmitting substrate, wherein said recording area is an uneven portion formed on a first surface, which is one surface of said substrate, which can be detected by irradiating said light. Optical recording medium. 15. A reflection film formed on a first surface of the substrate, wherein the light incident on the substrate is reflected from a second surface, which is the other surface of the substrate, and a part of the light is reflected. The optical recording medium according to claim 14, further comprising a transmitting reflection film. 16. The printing layer is a layer formed on a surface of the reflection film via a protective film, and the first region is configured to control the light transmitted through the reflection film and incident on the printing layer. The optical recording medium according to claim 15, wherein the optical recording medium is a region reflecting at a reflectance of: 17. The optical recording medium according to claim 11, wherein said recording area is made of a material which undergoes a phase change phenomenon by light irradiation and changes in a complex refractive index. 18. The optical recording medium according to claim 11, wherein said recording area is made of a material whose magnetization state changes by light irradiation and application of a magnetic field, and which can detect said change in said magnetization state as a change in polarization state. 19. The optical recording medium according to claim 11, wherein said recording area contains an organic dye whose maximum absorption wavelength changes by light irradiation. 20. A recording / reproducing method for an optical recording medium having an information recording area and reproducing recorded information by irradiating light, comprising: a step of recording information in the recording area; Forming, on one surface, a printing layer having a plurality of unique identification information recording areas, which are one of a first area and a second area, each having a different light transmittance; and irradiating the printing layer with the light. The first region and the second region
An optical recording medium recording / reproducing method, comprising: a step of detecting a distribution with respect to an area and reproducing the unique identification information of the optical recording medium; and a step of irradiating the recording area with the light to reproduce the recorded information. . 21. A step of reproducing the unique identification information and the recording information, the step of irradiating the recording area and the print layer with the light; 21. The method according to claim 20, further comprising the step of dividing the band into high-frequency parts, reproducing the unique identification information of the optical recording medium from the low-frequency signal, and reproducing the recording information of the optical recording medium from the high-frequency signal. A recording / reproducing method for an optical recording medium. 22. The method according to claim 22, wherein the step of forming the printing layer comprises the step of:
21. The recording / reproducing method for an optical recording medium according to claim 20, further comprising a step of forming a print area in an area and setting a non-print area as the second area. 23. The step of recording information in the recording area,
21. The recording / reproducing method for an optical recording medium according to claim 20, further comprising the step of forming a substrate constituting the optical recording medium by providing irregularities detectable by light irradiation on one surface. 24. The recording / reproducing method for an optical recording medium according to claim 20, wherein the step of recording information includes a step of causing a phase change phenomenon by irradiating the recording area with light to change a complex refractive index. 25. The step of recording information includes a step of changing a magnetization state of the recording area by light irradiation and application of a magnetic field, and the step of reproducing the recorded information includes irradiating the recording area with light. 21. The method according to claim 20, further comprising the step of detecting the change in the magnetization state as a change in the polarization state. 26. The recording / reproducing method for an optical recording medium according to claim 20, wherein the step of recording information includes a step of changing a maximum absorption wavelength of an organic dye contained in the recording area by light irradiation. 27. The step of reproducing the unique identification information and the recorded information, wherein the step of irradiating the light to make the transmitted light of the printing layer incident on the recording area; 21. The recording / reproducing method for an optical recording medium according to claim 20, further comprising: a step of reflecting light from the optical recording medium; and a step of detecting reflected light from the reflection film. 28. A recording / reproducing method for an optical recording medium having an information recording area and reproducing recorded information by irradiating light, comprising: a step of recording information in the recording area; Forming, on one surface, a printing layer having a plurality of unique identification information recording areas, each of which is a first area or a second area having different light reflectivities; and irradiating the printing layer with the light. The first region and the second region
An optical recording medium recording / reproducing method, comprising: a step of detecting a distribution with respect to an area and reproducing the unique identification information of the optical recording medium; and a step of irradiating the recording area with the light to reproduce the recorded information. . 29. The step of reproducing the unique identification information and the recorded information includes irradiating the recording area and the printing layer with the light, and reproducing a reproduction signal obtained by the light irradiation with a low-frequency part and a high-frequency part. 29. The method according to claim 28, further comprising a step of dividing the frequency band into high-frequency parts, reproducing the unique identification information of the optical recording medium from a low-frequency signal, and reproducing the recording information of the optical recording medium from a high-frequency signal. A recording / reproducing method for an optical recording medium. 30. The method according to claim 30, wherein the step of forming the printing layer comprises the step of:
29. The recording / reproducing method for an optical recording medium according to claim 28, further comprising a step of forming a print area in an area and setting a non-print area as the second area. 31. The step of recording information in the recording area,
29. The recording / reproducing method for an optical recording medium according to claim 28, further comprising a step of forming a substrate constituting the optical recording medium by providing irregularities detectable by light irradiation on one surface. 32. The recording / reproducing method for an optical recording medium according to claim 28, wherein the step of recording information includes a step of causing a phase change phenomenon by irradiating the recording area with light to change a complex refractive index. 33. The step of recording information includes a step of changing a magnetization state of the recording area by light irradiation and application of a magnetic field, and the step of reproducing the recorded information includes irradiating the recording area with light. 29. The recording / reproducing method for an optical recording medium according to claim 28, further comprising the step of detecting the change in the magnetization state as a change in the polarization state. 34. The recording / reproducing method for an optical recording medium according to claim 28, wherein the step of recording information includes a step of changing a maximum absorption wavelength of an organic dye contained in the recording area by light irradiation. 35. The step of reproducing the unique identification information and the recorded information, wherein the step of irradiating the light and reflecting the light transmitted through the recording area by a reflective film, and the step of reproducing the light transmitted through the reflective film by the print layer. 29. The recording / reproducing method of an optical recording medium according to claim 28, further comprising: a step of reflecting light from the optical recording medium;