JP2013211064A - Recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an illegal copy prevention function in a recording medium.SOLUTION: A recording medium comprises: a base with a shape having a rotational symmetry; a first information recording body disposed inside the base; and a second information recording body disposed on the top of the base. When the recording medium is illuminated by an illumination light source in a state where relative positional relation between the rotation center and the illumination light source is fixed, information is reproduced from a portion of the second information recording body corresponding to a rotation angle of the base.

Description

  The present disclosure relates to a recording medium. The present disclosure particularly relates to an information recording medium with an improved function of preventing unauthorized copying.

  For example, a so-called optical disk is used as a recording medium for contents such as video, music, and computer programs. As such optical discs, for example, CD (compact disc), DVD (Digital Versatile Disc), “Blu-ray Disc (registered trademark of Blu-ray Disc Association)” and the like are known.

  An optical disc is a recording medium having a recording area in which pits and lands are formed. By reading the arrangement of pits and lands with a pickup device including a laser light source, a bit string corresponding to the standard of each optical disc can be acquired, and information recorded in the recording area can be reproduced.

  In recent years, the increase in capacity of optical disks has been remarkable. With the increase in the density of information recorded on optical discs, the commercial value of optical discs on which information is recorded has also increased. On the other hand, the distribution of illegal copies, called pirated versions, has become a problem.

  For the purpose of preventing the distribution of unauthorized copies, a hologram seal is affixed to a recording medium itself such as an optical disc or a case for storing these.

  However, the hologram sticker attached to the recording medium or the case may be peeled off by an unauthorized person. For example, an authentic hologram seal peeled off from a recording medium or case may be diverted to an unauthorized copy product, or an unauthorized hologram seal copied using an authentic hologram seal as an original plate may be attached to an unauthorized copy product. was there.

  In order to prevent the removal of the hologram sticker affixed to the disk, for example, the following Patent Document 1 proposes that the hologram sticker is fitted into a recess provided in the hub, making it difficult to remove the hologram sticker. Yes.

JP 2004-005983 A

  Improvement of the function of preventing unauthorized copying in a recording medium is desired.

Preferred embodiments of the present disclosure include
The recording medium includes a base body having a rotationally symmetric shape, a first information recording body disposed inside the base body, and a second information recording body disposed on the base body.
When the recording medium is illuminated by the illumination light source with the relative positional relationship between the rotation center and the illumination light source being fixed, information is reproduced from the portion of the second information recording body corresponding to the rotation angle of the substrate. The

  According to at least one embodiment, the function of preventing unauthorized copying in the recording medium can be improved.

FIG. 1A is a plan view illustrating a recording medium according to an embodiment of the present disclosure. FIG. 1B is a diagram schematically showing a II-II cross section of FIG. 1A. FIG. 1C is a diagram schematically illustrating an example of a cross section of a recording medium according to an embodiment of the present disclosure. 2A to 2C are schematic views showing a photosensitivity process of the photopolymerizable photopolymer. FIG. 2D is a schematic diagram illustrating an example of a method for reading information from a recording medium. FIG. 3A is a plan view illustrating an example of a configuration of an original plate used in the recording medium manufacturing process according to the first embodiment. FIG. 3B is a diagram schematically showing the IX-IX cross section of FIG. 3A. FIG. 3C is an enlarged view of a W portion in FIG. 3B. 4A and 4B are schematic views showing an example of a hologram image recording method for the hologram layer of the transfer section. 5A to 5D are schematic diagrams illustrating a relationship between an incident angle of illumination light for reproducing a hologram image recorded on the transfer unit and an emission angle of reproduction light emitted from the transfer unit. 6A to 6C are schematic views illustrating an example of a method for manufacturing a recording medium according to the first embodiment. 7A to 7C are schematic views illustrating an example of a method for manufacturing a recording medium according to the first embodiment. FIG. 8A and FIG. 8B are diagrams showing an outline when the second information recording medium is exposed in units of lines. FIG. 8C and FIG. 8D are schematic diagrams showing how the hologram image recorded on the hologram layer of the transfer portion is duplicated on the second information recording body as the substrate rotates. FIG. 9A is a diagram showing a coordinate system set for the recording medium and the light source. 9B to 9D are schematic diagrams illustrating examples of hologram images observed from the recording medium when the recording medium is rotated in a state where the relative positional relationship between the center of the recording medium and the light source is fixed. FIG. 10A is a schematic diagram illustrating an example of a method of manufacturing an angle-selective holographic original plate that can be applied as a transfer portion. FIG. 10B is a schematic diagram showing a relationship between an incident angle of illumination light for reproducing a hologram recorded on the hologram layer of the transfer portion and an emission angle of reproduction light emitted from the transfer portion. FIG. 10C is observed from the transfer unit when the transfer unit illuminated by illumination light irradiated radially from the light source in the same arrangement as the virtual light source shown in FIG. 4B is observed from above. It is a schematic diagram showing an example of an image. FIG. 10D is a schematic diagram illustrating the principle of recording information on the second information recording body. FIG. 11A and FIG. 11B are schematic views showing an example of a barcode recording method for the second information recording body. FIG. 11C is a schematic diagram illustrating a configuration example of a barcode as a hologram image recorded in the second information recording body. FIG. 11D is a schematic diagram illustrating an example of a method for reading a barcode recorded in the second information recording body as a hologram image. FIG. 12A and FIG. 12B are schematic views showing another configuration example of the optical system for recording image data on the second information recording body. FIG. 12C is a schematic diagram illustrating another configuration example of a barcode as a hologram image recorded on the second information recording body. FIG. 12D is a schematic diagram illustrating a configuration example of a recording medium in which information including a medium ID is recorded in the first recording area and a barcode as a hologram image is recorded in the second recording area. FIG. 13A is a schematic diagram illustrating another configuration example for recording image data on the second information recording body. FIG. 13B is a schematic diagram illustrating an example of image data recorded in the second information recording medium. FIG. 13C is a schematic diagram illustrating an example of a method for reading image data recorded in the second information recording body as a hologram image. 14A to 14D are schematic diagrams illustrating a relationship between an incident angle of illumination light for reproducing a hologram image recorded on the transfer unit and an emission angle of reproduction light emitted from the transfer unit. 15A to 15C are schematic views illustrating an example of a method for manufacturing a recording medium according to the second embodiment. FIG. 16A is a diagram illustrating a coordinate system set for a recording medium and a light source. 16B to 16D are schematic diagrams illustrating examples of hologram images observed from the recording medium when the recording medium is rotated in a state where the relative positional relationship between the center of the recording medium and the light source is fixed. FIG. 17A is a schematic diagram illustrating another example of a method for manufacturing an angle-selective holographic original plate applicable as a transfer portion. FIG. 17B is a schematic diagram illustrating a relationship between an incident angle of illumination light for reproducing a hologram recorded on the hologram layer of the transfer portion and an emission angle of reproduction light emitted from the transfer portion. FIG. 17C shows a case where the angle formed by the upper surface of the transfer portion and the optical axis is 45 ° and the transfer portion illuminated with collimated laser light traveling in the −Y direction is observed. It is the schematic which shows an example of the hologram observed from. FIG. 17D and FIG. 17E are schematic diagrams illustrating a configuration example of a light source for recording image data on the second information recording body. 18A and 18B are diagrams showing a configuration example of a recording medium in which a second information recording body is arranged on the surface side of the substrate. 18C and 18D are schematic diagrams illustrating an example of a method for reading information from the second information recording body.

Hereinafter, embodiments of the recording medium will be described. The description will be made in the following order.
<1. First Embodiment>
[1-1. Schematic configuration of recording medium]
[1-2. Outline of recording medium manufacturing method]
(1-2-1. Example configuration of original plate)
(1-2-2. Transfer of second information recording medium and recording of information on second information recording medium)
[1-3. Reproduction of information from second information recording body]
[1-4. Recording of image data using angle-selective holographic master]
(1-4-1. Angle-selective holographic master)
(1-4-2. Example of image data recorded in the second information recording medium)
<2. Second Embodiment>
[2-1. Outline of recording medium manufacturing method]
(2-1-1. Configuration example of the original plate)
(2-1-2. Transfer of Second Information Recorder and Recording of Information on Second Information Recorder)
[2-2. Reproduction of information from second information recording body]
[2-3. Recording of image data using angle-selective holographic master]
(2-3-1. Angle-selective holographic master)
<3. Modification>

  The embodiment described below is a preferred specific example of the recording medium. In the following description, various technically preferable limitations are given. However, unless otherwise specified to limit the present disclosure, examples of the recording medium are not limited to the embodiments described below. .

<1. First Embodiment>
[1-1. Schematic configuration of recording medium]
FIG. 1A is a plan view illustrating a recording medium according to an embodiment of the present disclosure.

  As shown in FIG. 1A, the recording medium 1 includes, for example, a base 10 having a rotational symmetry such as a disk shape, a first information recording body 11, and a second information recording body 12. I have. The first information recording body 11 is disposed inside the base body 10, and the second information recording body 12 is disposed on the base body 10, for example.

  The first information recording body 11 is an information recording body on which information is recorded, for example, by modulation of reflection characteristics with respect to incident light. The first information recording body 11 can read information by an optical pickup, for example. Alternatively, for example, both reading and writing of information by an optical pickup are possible.

  On the other hand, the second information recording body 12 is an information recording body on which information is recorded by modulation of the refractive index. Specifically, the second information recording body 12 is a hologram recording layer in which information is recorded holographically. More specifically, information is recorded on the second information recording body 12 as a volume hologram. Therefore, the information recorded on the second information recording body 12 is reproduced by illuminating the recording medium 1 from the direction corresponding to the irradiation direction of the reference light when recording information on the second information recording body 12. Can be made.

  As described above, the information recorded in the second information recording body 12 is reproduced by light irradiation from a predetermined angle direction. In the present disclosure, when the recording medium is illuminated by the illumination light source in a state where the relative positional relationship between the rotation center and the illumination light source is fixed, from the portion corresponding to the rotation angle of the substrate in the second information recording body. , Information is played back.

  FIG. 1B is a diagram schematically showing a II-II cross section of FIG. 1A. 1B is a diagram schematically showing a cross section of the recording medium 1 shown in FIG. 1A. The thickness of each member shown in FIG. 1B does not represent the actual thickness of each member. The same applies to other figures of the present disclosure.

  As shown in FIGS. 1A and 1B, the base body 10 has, for example, a disk shape with a hole AP formed in the center. Examples of the material constituting the substrate 10 include polycarbonate, polymethyl methacrylate, epoxy resin, cyclic olefin resin, and polylactic acid.

  For example, a first information recording body 11 having an annular shape is disposed inside the base 10. Corresponding to the arrangement of the first information recording body 11, a first recording area R1 is formed in the recording medium 1.

  The first recording area R1 occupies most of the main surface of the recording medium 1, but the first information recording body 11 is arranged in the vicinity of the peripheral edge of the hole AP formed in the base 10. It is considered as an annular region that is not performed. A region from the peripheral edge of the hole AP formed in the base 10 to the inner diameter of the first recording region R1 is called a clamping area CL. For example, a reproducing apparatus including an optical pickup holds the clamping area CL of the recording medium 1 and gives a rotational motion to the recording medium 1 and reads information from the first recording area R1.

  The first information recording body 11 disposed inside the substrate 10 is an information recording layer that records information about contents such as video, music, and computer programs by modulating reflection characteristics with respect to incident light. Information about the content is recorded in the first information recording body 11 as bit strings of “0” and “1” corresponding to the reflection characteristics with respect to incident light, for example. That is, the recording medium 1 has a function as a so-called optical disk or magneto-optical disk.

  The configuration of the first information recording body 11 differs depending on the method of recording information on the first information recording body 11. In the present disclosure, the configuration of the first information recording body 11 is not limited to a specific method. The first information recording body 11 has a laminated structure of one or more layers made of, for example, a metal, a metal oxide, a dielectric, an organic dye, a magnetic material, or the like. When the recording medium 1 is configured as an optical disk, the first information recording body 11 has a concavo-convex shape corresponding to pits or grooves.

  As shown in FIGS. 1A and 1B, for example, a second information recording body 12 having an annular shape is disposed in at least a part of the clamping area CL. For example, a second recording region R <b> 2 is formed in the recording medium 1 corresponding to the second information recording body 12 disposed on the main surface on the back surface Bs side of the recording medium 1. In FIG. 1B, when the information recorded in the first recording region R1 is read or written in the recording medium 1, the surface on the side irradiated with the laser light on the first information recording body 11 is the back surface Bs. The so-called label surface opposite to the back surface Bs is shown as the front surface Ts. The same applies to the following description.

  Specifically, the second information recording body 12 is a hologram recording layer made of, for example, a photopolymerization type photopolymer. That is, the second information recording body 12 on which information is recorded is, for example, a volume hologram on which information is recorded by refractive index modulation. FIG. 1A shows a configuration example in which the logo of the manufacturer of the recording medium 1 is recorded on the second information recording body 12 as a reflection type volume hologram.

  In FIG. 1B, the second information recording body 12 is arranged on the back surface Bs of the recording medium 1 so that the surface of the second information recording body 12 is convex with respect to the back surface Bs. Although shown, the mode of arrangement of the second information recording body 12 is not limited to this example.

  FIG. 1C is a diagram schematically illustrating an example of a cross section of a recording medium according to an embodiment of the present disclosure.

  FIG. 1C shows a configuration example in which the second information recording body 12 is fitted in an annular groove provided in the clamping area CL of the base 13. For example, the back surface Bs of the base 13 of the recording medium 2 is provided with a recess, and the second information recording body 12 is disposed in the recess. By doing in this way, the surface which consists of the surface of the 2nd information recording body 12, and the back surface Bs of the base | substrate 13 can be made into a flat surface.

  2A to 2C are schematic views showing a photosensitivity process of the photopolymerizable photopolymer.

  In the initial state of the photopolymerization type photopolymer, as shown in FIG. 2A, the monomers M are uniformly dispersed in the matrix polymer.

As shown in FIG. 2B, when the photopolymerizable photopolymer is irradiated with light LA having a power of about 10 to 400 mJ / cm ² , the monomer M is polymerized in the exposed portion. As the monomer M becomes a polymer, the monomer M moves from the surroundings, and the concentration of the monomer M changes depending on the location. Thereby, refractive index modulation occurs.

Thereafter, as shown in FIG. 2C, the entire surface of the photopolymerizable photopolymer is irradiated with light LB having a power of about 1000 mJ / cm ² , thereby completing the polymerization of the monomer M. The light LB having a power of about 1000 mJ / cm ² is, for example, ultraviolet light or visible light.

  Since the refractive index of the photopolymerization type photopolymer changes according to the incident light, an interference pattern generated by the interference between the reference light and the object light can be recorded as the change of the refractive index. By using a photopolymerization type photopolymer, a special development process after exposure can be eliminated. Therefore, the configuration of the recording medium manufacturing apparatus according to the embodiment of the present disclosure can be simplified by using a photopolymerization type photopolymer as a material constituting the second information recording body 12.

  FIG. 2D is a schematic diagram illustrating an example of a method for reading information from a recording medium. The drawing shown in FIG. 2D corresponds to the II-II cross section of FIG. 1A. In FIG. 2D, illustration of a diffraction grating, a collimator, and the like in the optical pickup 111 is omitted.

  The information recorded in the first information recording body 11 is read by, for example, the optical pickup 111 as shown in FIG. 2D. Laser light emitted from the laser light source 113 inside the optical pickup 111 is reflected by the half mirror 115. The laser light reflected by the half mirror 115 enters the first information recording body 11 through the base 10 of the recording medium 1. A part of the light reflected by the first information recording body 11 passes through the half mirror 115 and reaches the photodetector 117.

  An analog signal related to the light reflected by the first information recording body 11 is obtained by the photoelectric conversion effect of the photodetector 117. The output from the photodetector 117 is converted into a digital signal by analog / digital conversion, and the digital signal obtained by the analog / digital conversion is decoded.

  On the other hand, the information recorded in the second information recording body 12 is reproduced by, for example, irradiation with illumination light IL from a predetermined angular direction as shown in FIG. 2D. Information as a hologram image reproduced from the second information recording body 12 in the second recording region R2 is read by an observer of the recording medium 1, for example. Alternatively, for example, information as a hologram image reproduced from the second information recording body 12 in the second recording region R2 is read by a dedicated reading device.

  For example, the illumination light IL incident on the recording medium 1 from the surface Ts side reaches the second information recording body 12 via the base 10 and is diffracted by the second information recording body 12. The reproduction light DL diffracted by the second information recording body 12 is emitted from the second information recording body 12 toward the surface Ts side of the recording medium 1. That is, in FIG. 2D, for example, the observer of the recording medium 1 observes the hologram image reproduced from the second information recording body 12 through the substrate 10.

  As shown in FIG. 2D, for example, a louver 15 is preferably disposed on the back side of the second information recording body 12. The louver 15 has a configuration in which, for example, a planar black absorption layer is arranged inside a transparent plate at regular intervals. By arranging the louver 15 adjacent to the second information recording body 12 as the hologram recording layer, the contrast of the hologram image is increased and the visibility of the hologram image reproduced from the second information recording body 12 is improved. To do. Instead of the louver 15, for example, a black base material may be disposed adjacent to the second information recording body 12.

  As described above, the hologram image recorded on the second information recording body 12 as the hologram recording layer is reproduced by irradiation of illumination light from a predetermined angle direction. Here, the predetermined angle direction is an angle direction determined by the incident angle of the reference light and the incident angle of the object light used for recording information on the second information recording body 12. .

[1-2. Outline of recording medium manufacturing method]
The recording medium according to the embodiment of the present disclosure is generally manufactured by disposing the second information recording body in the clamping area of the substrate in which the first information recording body is disposed. . Preferably, information is recorded on the second information recording body together with the arrangement of the second information recording body in the clamping area.

  Hereinafter, an example of a method for manufacturing a recording medium according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the manufacturing method of the substrate in which the first information recording body is arranged is almost the same as the manufacturing method of a general optical disk, and thus the description thereof is omitted.

(1-2-1. Example configuration of original plate)
As will be described later, the recording of information on the second information recording body is performed, for example, by duplicating information recorded in advance on the original plate on the second information recording body. Therefore, prior to the description of the recording medium manufacturing method according to the embodiment of the present disclosure, first, the configuration of the original plate applicable to the recording medium manufacturing process will be described.

  FIG. 3A is a plan view illustrating an example of a configuration of an original plate used in the recording medium manufacturing process according to the first embodiment. FIG. 3B is a diagram schematically showing the IX-IX cross section of FIG. 3A.

  As shown in FIGS. 3A and 3B, the original plate 51 includes, for example, a transfer portion 61 and a base portion 65.

  The transfer part 61 has an annular shape as a whole and has a flat upper surface Fs. That is, the transfer portion 61 has a shape corresponding to the second recording region R2 formed on the recording medium 1. For example, if the inner diameter and the outer diameter of the second recording region R2 are r1 and r2, respectively, the inner diameter and the outer diameter of the transfer portion 61 are set approximately equal to r1 and r2, respectively.

  The base portion 65 is made of, for example, a metal or a resin material, and functions as a support base material for the transfer portion 61.

  FIG. 3C is an enlarged view of a W portion in FIG. 3B.

  As shown in FIG. 3C, the transfer unit 61 includes, for example, a hologram layer 71 sandwiched between a glass plate 73a and a glass plate 73b. The hologram layer 71 is a layer made of, for example, the above-described photopolymerization type photopolymer.

  Moreover, as shown to FIG. 3C, the coat layer 75 is provided in the surface of the glass plate 73a, for example. The coat layer 75 is a layer containing, for example, fluorine or silicone. Specifically, the coat layer 75 is a layer made of, for example, a fluororesin. Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and tetrafluoroethylene / ethylene copolymer. Examples thereof include a polymer (ETFE), polyvinylidene fluoride (PVDF), and polychlorotrifluoroethylene (PCTFE).

  As will be described later, the second recording region R2 is formed, for example, by transferring the material constituting the second information recording body 12 from the upper surface Fs of the transfer unit 61 to the clamping area CL of the base 10. Is done. That is, the coat layer 75 is provided on the surface of the glass plate 73a in order to improve the peelability of the material constituting the second information recording body 12 with respect to the upper surface Fs of the transfer portion 61.

  In addition, when recording the information on the second information recording body 12 together with the arrangement of the second information recording body 12 in the clamping area CL, it is preferable that the light transmittance of the coat layer 75 is high.

  As indicated by a broken line in FIG. 3A, for example, information to be recorded in the second information recording body 12 is recorded in the hologram layer 71 in advance as a hologram image. FIG. 3A shows a configuration example in which the logo of the manufacturer of the recording medium 1 is recorded on the hologram layer 71 of the transfer unit 61 as a reflective volume hologram. Hereinafter, an example of a method for recording a hologram image on the hologram layer 71 of the transfer unit 61 will be described.

  4A and 4B are schematic views showing an example of a hologram image recording method for the hologram layer of the transfer section. 4A corresponds to a view of the transfer portion 61 as viewed from above, and FIG. 4B corresponds to a cross-sectional view of the transfer portion 61 as viewed from the side. Hereinafter, for convenience of explanation, in XYZ orthogonal coordinates, a plane parallel to the upper surface Fs of the original plate is defined as an XY plane, and a direction from the base portion of the original plate toward the transfer portion is defined as a + Z direction.

In order to record a hologram image on the hologram layer 71 of the transfer unit 61, first, for example, a reflection type volume hologram in which hologram recording is performed with an incident angle of reference light being 45 ° and an incident angle of object light being 180 °. H _i (i = 0, 1, 2,...) Is prepared. The recording of these volume holographic image on the hologram H _i, for example, it is assumed that the wavelength is performed by using the green laser beam of about 532 nm.

Next, as shown in FIG. 4A, these volume holograms H _i are arranged in an annular shape corresponding to the annular shape of the transfer portion 61. At this time, a plurality of hologram images are reproduced from each of the plurality of volume holograms H _i when the illumination light is irradiated radially from the center of the transfer portion 61 and from the direction Z≈ (r1 + r2) / 2. The arrangement of each of the volume holograms H _i is adjusted. Further, the volume hologram _Hi and the transfer unit 61 are brought into close contact with each other directly or through an index matching liquid.

Next, the plurality of volume holograms H _i and the transfer unit 61 are irradiated with green laser light. For example, the green laser light is emitted from a light source 77 disposed in the center of the transfer portion 61 that has an annular shape and at a position where Z <0. The green laser light emitted from the light source 77 is incident on the plurality of volume holograms H _i and the transfer unit 61 by being reflected by, for example, a conical mirror 79 disposed above the transfer unit 61.

The angle formed by the projection of the conical bus of the mirror 79 onto the ZX plane and the Z axis is set to approximately 67.5 °. Therefore, with respect to each of the plurality of volume hologram H _i, as shown in FIG. 4B, the green laser beam from the virtual light source VS is a state as if it were irradiated disposed on the back side of the mirror. Thus, from each of the plurality of volume hologram H _i, the reproducing light a hologram image recorded is emitted toward the + Z direction.

Then, the reproduction light from each of the plurality of volume hologram H _i and (object light), a green laser beam reflected by the mirror 79 (the reference light), but will interfere with each other in the hologram layer 71 of the transfer unit 61 The interference pattern is recorded on the hologram layer 71 of the transfer unit 61. In other words, the hologram image recorded on each of the plurality of volume hologram H _i, as a reflection type hologram is replicated on the hologram layer 71 of the transfer unit 61.

After replication of the hologram image recorded on each of the plurality of volume holograms H _i with respect to the hologram layer 71 of the transfer unit 61 is completed, the plurality of volume holograms H _i are peeled off from the transfer unit 61. The transfer portion 61 is bonded to the base portion 65 with an adhesive or the like, and the coating layer 75 is formed on the surface of the glass plate 73a, whereby the original plate 51 shown in FIGS. 3A to 3C is obtained.

  5A to 5D are schematic diagrams illustrating a relationship between an incident angle of illumination light for reproducing a hologram image recorded on the transfer unit and an emission angle of reproduction light emitted from the transfer unit.

  For example, as shown in FIGS. 5A and 5B, illumination light is emitted from a laser light source (the light source is shown by a broken line in FIGS. 5A and 5B) in the same arrangement as the virtual light source VS shown in FIG. 4B. Is emitted radially toward the upper surface Fs of the transfer portion 61.

  In this case, the illumination light is incident on the transfer unit 61 from a direction substantially the same as the direction in which the reference light is incident when the hologram image is copied on the hologram layer 71 of the transfer unit 61. Therefore, as shown in FIG. 5A and FIG. 5B, the reproduction light related to the hologram image is emitted from almost all the region of the transfer unit 61. Note that the reproduction light at this time is emitted from the transfer unit 61 in the + Z direction substantially parallel to the Z axis.

  Here, for example, as illustrated in FIG. 5C, a case is assumed where the parallel light of the green laser traveling in the + Y direction is irradiated at an angle of 45 ° with respect to the upper surface Fs of the transfer unit 61.

  In this case, as shown in FIG. 5C, from the region of the transfer unit 61 in which the parallel light incident direction of the green laser is substantially the same as the incident direction of the reference light when the hologram image is replicated, Reproduction light is emitted. On the other hand, the reproduction light related to the hologram image is not emitted from the other area of the transfer unit 61. That is, when the transfer unit 61 is observed from above, as shown in FIG. 5D, a recorded hologram image is reproduced from an area of the transfer unit 61 according to the direction in which the green laser light as the illumination light is incident. . In FIG. 5D, the reproduced hologram image is shown by shading.

(1-2-2. Transfer of second information recording medium and recording of information on second information recording medium)
Next, the process of disposing the material constituting the second information recording body 12 in the clamping area CL of the substrate 10 and the process of recording information on the second information recording body 12 will be described. Information is recorded on the second information recording body 12 by, for example, copying information previously recorded on the transfer unit 61 of the original 51 to the second information recording body 12.

  6A to 6C and FIGS. 7A to 7C are schematic views illustrating an example of a method for manufacturing a recording medium according to the first embodiment.

  When disposing the material constituting the second information recording body 12 in the clamping area CL, for example, as shown in FIG. 6A, first, the second information recording body 12 is configured on the upper surface Fs of the transfer portion 61. The material to be applied is applied. As a material constituting the second information recording body 12 applied to the upper surface Fs of the transfer section 61, typically, a photopolymerization type photopolymer is cited.

  The material constituting the second information recording body 12 is applied in an annular shape on the upper surface Fs of the transfer unit 61 in accordance with the shape of the upper surface Fs of the transfer unit 61. At this time, the material constituting the second information recording body 12 is in an uncured or semi-cured state (hereinafter, this state is appropriately referred to as a wet state).

  Next, the original plate 51 coated with the material constituting the second information recording body 12 is opposed to the upper surface Fs of the transfer portion 61 with respect to the base body 10 in which the first information recording body 11 is disposed. . At this time, for example, the clamping area CL on the back surface Bs side of the substrate 10 and the material constituting the second information recording body 12 applied to the upper surface Fs of the transfer unit 61 face each other.

  Next, as shown in FIG. 6B, the original 51 is pressed against the substrate 10. By pressing the original plate 51 against the substrate 10, the wet photopolymerization photopolymer is brought into close contact with the clamping area CL on the back surface Bs side of the substrate 10.

  Next, as shown in FIG. 6C, the parallel light of the green laser traveling in the + Y direction, for example, is irradiated to the material and the transfer unit 61 constituting the second information recording body 12 through the substrate 10. The At this time, the incident angle of the green laser light with respect to the substrate 10 is set so that the incident angle of the green laser light with respect to the transfer portion 61 is approximately 45 °.

  Due to the irradiation with the green laser light, the transfer unit 61 emits reproduction light related to the hologram image recorded on the hologram layer 71 of the transfer unit 61. Therefore, the reproduction light (object light) from the hologram layer 71 of the transfer unit 61 and the green laser light (reference light) interfere with each other in the second information recording body 12, and the second information recording body 12. An interference pattern is recorded in In other words, the hologram image recorded on the hologram layer 71 of the transfer unit 61 is duplicated on the second information recording body 12.

  Here, when the green laser light travels in the + Y direction and is incident at an angle of 45 ° with respect to the upper surface Fs of the transfer portion 61, the transfer is performed as described with reference to FIGS. 5C and 5D. The hologram image reproduced from the unit 61 is a part of the whole. That is, a part of the hologram image recorded on the hologram layer 71 of the transfer unit 61 is duplicated on the second information recording body 12.

  Therefore, the base 10 and the original 51 are rotated continuously or intermittently by a constant angle, and the parallel light of the green laser is irradiated on the base 10 and the original 51. The rotation axis at this time is an axis that passes through the center of the substrate 10 having a disk shape, for example, and is perpendicular to the XY plane. By irradiating the parallel light of the green laser while rotating the base body 10 and the original plate 51 at a constant angle continuously or intermittently, the entire hologram image recorded on the hologram layer 71 of the transfer unit 61 is converted into the second image. The information recording body 12 can be replicated sequentially.

  Note that a mask provided with a fan-shaped opening may be arranged between the green laser light source and the substrate 10 so that the second information recording body 12 is irradiated with the green laser light.

  When the reproduction of the hologram image recorded in the hologram layer 71 of the transfer unit 61 with respect to the second information recording body 12 is completed, for example, from the hole AP of the base 10 toward the original 51 as shown in FIG. 7A. Compressed air AR is sent. By sending the compressed air AR from the hole AP of the base 10 toward the original 51, the base 10 and the original 51 are separated as shown in FIG. 7B. At this time, since the coating layer 75 is provided on the original 51, the material constituting the second information recording body 12 is peeled off from the upper surface Fs of the transfer portion 61, and the material constituting the second information recording body 12. Is transferred to the clamping area CL of the substrate 10. That is, the second information recording body 12 is disposed in the clamping area CL of the base body 10 in which the first information recording body 11 is disposed.

  Instead of transferring the material constituting the second information recording body 12 from the upper surface Fs of the transfer portion 61 to the clamping area CL of the base body 10, the second information recording body 12 is transferred to the clamping area CL of the base body 10. The material constituting the body 12 may be applied in advance.

  After the transfer of the material constituting the second information recording body 12 to the clamping area CL of the substrate 10, ultraviolet rays for fixing the recorded image to the second information recording body 12 as necessary. Post-processing such as irradiation and heating is performed. Further, the louvers 15 are arranged on the surface of the second information recording body 12 and a protective layer is formed as necessary. As described above, as illustrated in FIG. 7C, the recording medium 1 according to the embodiment of the present disclosure is obtained.

  In the above-described example, in recording information on the second information recording body 12, the second information recording body 12 arranged in the clamping area CL is exposed on a surface basis. Instead of exposing the second information recording body 12 arranged in the clamping area CL in units of planes, it is also possible to expose the second information recording body 12 in units of lines or points.

  FIG. 8A and FIG. 8B are diagrams showing an outline when the second information recording medium is exposed in units of lines.

  As shown in FIGS. 8A and 8B, for example, the laser light emitted from the laser light source 91 is expanded by the beam expander 93 and then collected in a substantially linear shape by the cylindrical lens set 95 or the like. In this case, the exposure area by the laser beam (parallel light) formed in a substantially linear shape is a linear area along the Y axis. Therefore, recording of information on the second information recording body 12 is completed by rotating the substrate 10 360 ° in a plane parallel to the main surface under the irradiation of the laser beam from the optical system 81. .

  FIG. 8C and FIG. 8D are schematic diagrams showing how the hologram image recorded on the hologram layer of the transfer portion is duplicated on the second information recording body as the substrate rotates. In FIG. 8C and FIG. 8D, illustrations other than the clamping area CL of the recording medium 1 are omitted.

  8C and 8D are schematic diagrams showing changes in the amount of information recorded in the second information recording body 12 as changes in the pattern. 8C and 8D, the exposure area is indicated by a broken line EX.

  The rotation angle of the substrate 10 in the state shown in FIG. 8D is larger than the rotation angle of the substrate 10 in the state shown in FIG. 8C. As shown in FIG. 8C and FIG. 8D, when the substrate 10 rotates relative to the linear exposure region, the hologram image recorded on the hologram layer 71 of the transfer unit 61 becomes the second information. The recording material 12 is sequentially duplicated.

[1-3. Reproduction of information from second information recording body]
Hereinafter, an example of a hologram image observed from a recording medium will be described. For convenience of explanation, some variables are defined.

  FIG. 9A is a diagram showing a coordinate system set for the recording medium and the light source. In the description so far, the original plate has been described as being in the XYZ orthogonal coordinate system. However, the X axis, the Y axis, and the Z axis are similarly assumed for the light source and the recording medium that illuminate the recording medium. To do.

  As shown in FIG. 9A, a plane parallel to the surface Ts of the recording medium 1 is defined as an XY plane, and a direction from the back surface Bs of the recording medium 1 toward the surface Ts is defined as a + Z direction. The Z axis passes through the center of the recording medium 1. The X-axis direction and the Y-axis direction with respect to the recording medium 1 are the X-axis direction and the Y-axis direction when the material constituting the second information recording body 12 is transferred to the clamping area CL of the substrate 10. Each shall match.

  Here, a point p fixed on the main surface of the recording medium 1 is assumed, and a line segment mr connecting the point p and the center of the recording medium 1 is assumed. The X axis, the Y axis, and the Z axis are fixed, and the rotation angle of the recording medium 1 with the Z axis as the rotation axis is represented by an angle α formed by the X axis and the line segment mr.

  The position of the light source 82 that irradiates the recording medium 1 with illumination light is represented by a set of an azimuth angle φ measured from the X axis and a zenith angle θ measured from the Z axis, as necessary.

  9B to 9D are schematic diagrams illustrating examples of hologram images observed from the recording medium when the recording medium is rotated in a state where the relative positional relationship between the center of the recording medium and the light source is fixed. 9B to 9D, illustrations other than the clamping area CL of the recording medium 1 are omitted.

  9B to 9D show a state in which the recording medium 1 is illuminated with white light from a light source arranged in the direction of (φ, θ) = (270 °, 45 °). In other words, the angle formed by the surface Ts of the recording medium 1 and the optical axis of the illumination light is set to 45 °.

  Under such illumination, as shown in FIG. 9B, the observer of the recording medium 1 makes | X | <ε and Y> 0 (ε> 0) in the second recording region R2. .) Can be observed.

  Next, it is assumed that α is increased from the state shown in FIG. 9B. That is, if the recording medium 1 is rotated in the forward direction, the observer of the recording medium 1 observes a hologram image different from that shown in FIG. 9B, as shown in FIG. 9C. Even in this case, the area where the hologram image is reproduced is in the range of | X | <ε and Y> 0 in the second recording area R2.

  Next, if α is further increased, as shown in FIG. 9D, a hologram image different from the case shown in FIG. 9B and the case shown in FIG. 9C is observed by the observer of the recording medium 1. Also in this case, the region where the hologram image is reproduced is in the range of | X | <ε and Y> 0 in the second recording region R2.

  Thus, in the first embodiment, when the recording medium is illuminated by the illumination light source while the relative positional relationship between the rotation center of the recording medium and the illumination light source is fixed, Information is reproduced from the portion corresponding to the rotation angle of the substrate.

  As described above, in the first embodiment, the second information recording body arranged in the clamping area is divided into a plurality of areas and sequentially exposed. Therefore, when the recording medium is illuminated from the direction corresponding to the incident direction of the reference light at the time of duplicating the hologram image on the second information recording body and the recording medium is rotated, the hologram is generated from the area corresponding to the incident direction of the illumination light. Images are played back sequentially.

  As is apparent from the above description, if the illumination light is irradiated radially toward the surface Ts of the recording medium 1 from the light source in the same arrangement as the virtual light source VS shown in FIG. 4B, the second recording is performed. Of course, it is also possible to reproduce the hologram image from the entire surface of the region R2.

[1-4. Recording of image data using angle-selective holographic master]
In the description so far, the configuration example in which the information recorded on the second information recording body is recorded by duplicating the information recorded in advance on the original plate on the second information recording body has been shown. In the present disclosure, the specifications of the original plate are changed as appropriate, and the second information recording body is sequentially exposed in units of lines or points, so that information is directly transmitted to the second information recording body as image data. It is also possible to record in

(1-4-1. Angle-selective holographic master)
In order to directly record information on the second information recording body using light rays incident from one direction, the entire surface of the region where light for recording information is incident on the second information recording body An original on which a hologram for uniformly diffracting incident light in a specific direction is recorded is used. In the present disclosure, an optical functional element that diffracts light incident from a predetermined direction almost uniformly in a specific direction will be referred to as an “angle-selective holographic master”.

  The angle-selective holographic master is a master (which may be said to be a master with uniform diffraction characteristics) having uniform diffraction light intensity and angle selectivity with respect to incident light over the entire surface where light enters. It is configured. That is, the angle-selective holographic original is typically a holographic original in which a specific picture or character is not recorded. As will be apparent from the following description, the angle-selective holographic master can make a partial optical copy by selecting a region by making diffraction characteristics and diffusion performance almost uniform. This is the original version. Note that “uniform” refers to global uniformity, not local uniformity.

  FIG. 10A is a schematic diagram illustrating an example of a method of manufacturing an angle-selective holographic original plate that can be applied as a transfer portion.

  In order to configure the transfer portion of the original plate as an angle-selective holographic original plate, for example, as shown in FIG. 10A, for example, with respect to almost the entire surface of the hologram layer of the transfer portion 62, Then, mutually coherent laser beams are made incident. At this time, for example, one of the laser beams (corresponding to reference light) is from a light source (the light source is indicated by a broken line in FIG. 10A) in the same arrangement as the virtual light source VS illustrated in FIG. 4B. The transfer unit 62 is set so as to be in the same state as when the laser beam is irradiated radially. The other laser beam (corresponding to the object beam) is set to enter the transfer portion from the side opposite to the laser beam corresponding to the reference beam. That is, for example, the incident angle of laser light corresponding to object light is set to 180 °.

  The two laser beams incident from the respective main surfaces of the transfer unit 62 interfere with each other in the hologram layer of the transfer unit 62. Therefore, the transfer unit 62 becomes a holographic original plate in which a hologram for uniformly diffracting light incident from a predetermined direction in a specific direction is uniformly recorded.

  FIG. 10B is a schematic diagram showing a relationship between an incident angle of illumination light for reproducing a hologram recorded on the hologram layer of the transfer portion and an emission angle of reproduction light emitted from the transfer portion.

  As shown in FIG. 10B, from a light source (the light source is indicated by a broken line in FIG. 10B) in the same arrangement as the virtual light source VS shown in FIG. 4B to the transfer unit 62 provided in the original plate 52. Assuming that the transfer unit 62 is illuminated with illumination light that is irradiated radially, the reproduction light is emitted in the + Z direction.

  FIG. 10C is observed from the transfer unit when the transfer unit illuminated by illumination light irradiated radially from the light source in the same arrangement as the virtual light source shown in FIG. 4B is observed from above. It is a schematic diagram showing an example of an image.

  For example, when the transfer unit 62 is illuminated from a light source in the same arrangement as the virtual light source VS illustrated in FIG. 4B and the transfer unit 62 is observed from above, the observer of the transfer unit 62 can observe the hologram layer of the transfer unit 62. The recorded hologram can be confirmed. That is, for example, when a hologram is recorded using a green laser, the entire surface of the transfer unit 62 appears green under illumination of green laser light from a predetermined direction. In FIG. 10C, a region that appears green when the transfer portion 62 is observed is shown by shading.

  FIG. 10D is a schematic diagram illustrating the principle of recording information on the second information recording body. FIG. 10D is an enlarged view showing the material constituting the second information recording body 12 and a part of the original plate 52 applied on the upper surface Fs of the transfer unit 62. In FIG. 10D, only the second information recording body 12 arranged in the clamping area CL of the recording medium is shown, and the substrate 10 and the like are not shown.

  As shown in FIG. 10D, for example, the illumination light RL for recording image data is incident on the material constituting the original plate 52 and the second information recording body 12 at an angle of 45 ° with respect to the transfer unit 62. To do. For example, when a hologram image is recorded on the hologram layer of the transfer unit 62 by a green laser having a wavelength of about 532 nm, green laser light is selected as the illumination light RL for recording image data.

  The light that has passed through the material constituting the second information recording body 12 and reached the hologram layer of the transfer unit 62 is diffracted by the transfer unit 62 configured as an angle-selective holographic master, and is directed toward the + Z direction. The light is emitted from the transfer unit 62.

  Then, the illumination light RL for recording image data and the light diffracted by the transfer unit 62 configured as an angle selective holographic master and emitted toward the material constituting the second information recording body 12 are: Interference occurs in the second information recording body 12. That is, the diffracted light (object light) from the transfer unit 62 and the illumination light RL (reference light) for recording image data interfere in the second information recording body 12, and the second information recording is performed. An interference pattern is recorded on the body 12.

  The interference between the diffracted light (object light) from the transfer unit 62 and the illumination light RL (reference light) for recording image data is caused by the image in the region where the illumination light RL for recording image data is incident. The illumination light RL for recording data is generated only in the vicinity of the region diffracted by the transfer unit 62. In FIG. 10D, the illumination light RL for recording image data and the light diffracted by the transfer unit 62 incident on the material constituting the second information recording body 12 are shown by shading, and an interference region Ω Is shown by dark shading.

  As described above, the transfer unit 62 configured as an angle selective holographic original is disposed at a position close to the second information recording body 12. Further, by irradiating illumination light RL for recording image data from a predetermined direction toward a desired area of the second information recording body 12, the vicinity of the desired area of the second information recording body 12 An interference pattern can be recorded only in At this time, the second information recording body 12 and the transfer unit 62 are irradiated with laser light obtained by pulse oscillation or modulated laser light as illumination light RL for recording image data. Characters and figures can be recorded on the second information recording body 12. In other words, for example, a desired area of the second information recording body 12 is selectively exposed by using an original provided with a transfer portion configured as an angle selective holographic original, and the desired information is reflected. Can be recorded as a pattern of the hologram image.

(1-4-2. Example of image data recorded in the second information recording medium)
FIG. 11A and FIG. 11B are schematic views showing an example of a barcode recording method for the second information recording body.

  11A and 11B show a configuration example of the optical system 83 in which the shutter 97 is disposed between the laser light source 91 and the beam expander 93. FIG. With the opening and closing of the shutter 97, the second information recording body 12 is intermittently irradiated with light that is shaped substantially linearly.

  By controlling the opening and closing of the shutter 97, when the material constituting the second information recording body 12 is arranged in the clamping area CL of the base 10, for example, the base 10 is formed in a substantially linear shape while rotating. The second information recording body 12 can be irradiated intermittently with the laser beam. The second information recording body 12 is imaged as image data by intermittently irradiating the second information recording body 12 with laser light that is shaped substantially linearly while rotating the substrate 10. Bar code can be recorded.

  FIG. 11C is a schematic diagram illustrating a configuration example of a barcode as a hologram image recorded in the second information recording body. In FIG. 11C, illustrations other than the clamping area CL of the recording medium 3 are omitted.

  The bar code recorded on the second information recording body 12 by intermittently irradiating the substantially linearly shaped laser beam has a form in which a plurality of bars extending in the radial direction are arranged in an annular shape. Therefore, the bar code recorded on the second information recording body 12 has information along the circumferential direction.

  Furthermore, the barcode shown in FIG. 11C is recorded in the second information recording body 12 as a hologram image reproduced when illuminated from a predetermined direction. In FIG. 11C, for convenience of explanation, a plurality of bars extending in the radial direction are shown as being reproduced.

  FIG. 11D is a schematic diagram illustrating an example of a method for reading a barcode recorded in the second information recording body as a hologram image.

  For example, as in the case of barcode recording, the recording medium 3 is configured so that a substantially linearly shaped laser beam extending in the + Y direction is incident on the second information recording body 12 at an angle of 45 °. Is irradiated. Then, if a bar as a hologram image is recorded in the region irradiated with the laser beam, the laser beam incident on the second information recording body 12 is diffracted in the + Z direction. On the other hand, if no bar as a hologram image is recorded in the region irradiated with the laser light, the laser light incident on the second information recording body 12 is not diffracted in the + Z direction.

  Therefore, for example, as illustrated in FIG. 11D, the photodetector 119 is disposed so as to face the irradiation region of the laser light as the illumination light in the second recording region R2 of the recording medium 3. Then, while rotating the recording medium 3, the second recording area R 2 of the recording medium 3 is irradiated with laser light from a predetermined angle direction, whereby the barcode pattern recorded on the second information recording body 12 is formed. A corresponding signal can be acquired by the photodetector 119. The arrangement of the laser light source and the photodetector 119 with respect to the recording medium 3 can be arbitrarily set by appropriately changing the specifications of the transfer unit 62.

  By the way, the barcode as the hologram image recorded in the second information recording body 12 can be confirmed visually by illuminating the recording medium 3 from a predetermined angle direction, for example. In the case of pattern detection by the light detector 119, it is only necessary to detect the presence or absence of diffracted light by the light detector 119. Therefore, the information recorded in the second information recording body 12 is not necessarily reproducible by white light. There is no need to be done.

  FIG. 12A and FIG. 12B are schematic views showing another configuration example of the optical system for recording image data on the second information recording body.

  12A and 12B show a configuration example of the optical system 85 in which the light modulation element 99 is disposed between the beam expander 93 and the cylindrical lens set 95. As shown in FIGS. 12A and 12B, the laser light emitted from the laser light source 91 is expanded by the beam expander 93 and enters the light modulation element 99. The laser light incident on the light modulation element 99 is modulated by the light modulation element 99. The laser light incident on the light modulation element 99 is modulated by the light modulation element 99, converted into parallel light by the set of cylindrical lenses 95, and then incident on the second information recording body 12.

  The light modulation element 99 is, for example, a liquid crystal panel that is driven in accordance with a control signal input to the driver. By sequentially switching the images displayed on the liquid crystal panel, it is possible to switch between transmission and blocking of laser light in each pixel of the liquid crystal panel. For example, the laser beam expanded by the beam expander 93 can be modulated by the light modulation element 99 with respect to the radial direction of the recording medium.

  FIG. 12C is a schematic diagram illustrating another configuration example of a barcode as a hologram image recorded on the second information recording body. In FIG. 12C, illustrations other than the clamping area CL of the recording medium 5 are omitted.

  For example, when the laser beam expanded by the beam expander 93 is modulated by the light modulation element 99 in the direction along the radial direction of the recording medium 5, as shown in FIG. It can also be a group of annular barcodes. By configuring the annular barcode as a group of a plurality of annular barcodes, more information can be recorded in the second information recording body 12 than in the case shown in FIG. 11C. .

  Note that, instead of including the shutter 97 and the light modulation element 99 in the optical system for generating illumination light for recording image data, a desired shape is provided between the optical system and the second information recording body 12. You may make it arrange | position the mask provided with this opening. Along with the rotation of the recording medium, for example, a desired pattern can be recorded on the second information recording body 12 by switching a plurality of prepared masks or shifting the position of the opening of the mask.

  By the way, an optical key having a relatively large data capacity, such as a DVD or “Blu-ray Disc (registered trademark)”, has an encryption key (Media Key Block (MKB)) for the purpose of protecting contents and copyrights. And a unique ID (identification data) (referred to as a media ID) is assigned to each optical disc.

  The MKB and the media ID are recorded as a barcode pattern in the lead-in area near the inner diameter of the first recording area R1. The area in which the MKB and the media ID are recorded is called a burst cutting area (BCA) or a narrow burst cutting area (NBCA).

  FIG. 12D is a schematic diagram illustrating a configuration example of a recording medium in which information including a medium ID is recorded in the first recording area and a barcode as a hologram image is recorded in the second recording area. In FIG. 12D, the first recording area R1 is indicated by shading.

  For example, when the recording medium 6 has an MKB and a media ID, as shown in FIG. 12D, information associated with the MKB and the media ID is displayed on the second information recording body 12 by a mode such as a barcode. It can be recorded as an image. By associating the information recorded in the second information recording body 12 with the MKB and the media ID, for example, it is possible to make the disc player determine whether or not the recording medium to be reproduced is authentic. It is. Whether or not the recording medium to be reproduced is authentic can be determined by, for example, an inquiry to a database connected to the network. In addition, for example, in order to prevent a disc determined to be a pirated version from being played, an external command is sent to the disc player or a recording medium on which a program or music is recorded is exchanged with the database. It is also possible to do.

  Alternatively, for example, information required for reproduction of content recorded in the first information recording body 11 or content recording on the first information recording body 11 is required for the second information recording body 12. Information may be recorded holographically. That is, the information recorded in the second information recording body 12 may be a decryption key for reproducing content or a part of an encryption key for recording content.

  When the information recorded on the second information recording body 12 is read by, for example, a photodetector, the illumination light source for reproducing the information, the recording medium, and the photodetector are relative to each other inside the disc player. The positional relationship needs to be appropriate. In other words, the arrangement of the illumination light source, the recording medium, and the photodetector itself can also constitute a part of the decryption key or encryption key. Therefore, by recording information associated with the information recorded on the first information recording body 11 on the second information recording body 12, unauthorized copying of an optical disk or the like is prevented, and the contents of the recording medium The protection function can be improved.

  12A to 12D show a configuration example in which laser light is modulated in the radial direction of the recording medium by the light modulation element, and a plurality of annular barcode groups are recorded on the second information recording body 12. However, the image data recorded on the second information recording body 12 is not limited to this example. For example, by modulating the laser beam with respect to the radial direction of the recording medium, identification information for identifying each recording medium to be manufactured can be superimposed on the laser beam. For example, it is of course possible to record a serial number, a lot number, etc. as a hologram image on the second information recording body 12 by modulating the laser beam with respect to the radial direction of the recording medium using an optical modulation element. .

  Instead of modulating the laser beam with respect to the radial direction of the recording medium by the light modulation element, the point light sources are arranged in a line, and the on and off of the individual light sources are controlled, so that the point light is drawn. The image data may be recorded on the second information recording body 12.

  In the above-described example, the configuration example in which the second information recording body 12 is exposed by the laser beam shaped substantially linearly has been shown. However, the second information recording body is scanned by dot-like light. Twelve exposures can also be performed.

  FIG. 13A is a schematic diagram illustrating another configuration example for recording image data on the second information recording body.

  As shown in FIG. 13A, an optical system 87 for irradiating illumination light for recording image data includes a laser light source 91, a light modulator 101, a shutter 97, and a galvano scanner (also called a galvanometer scanner). 103 and a lens group 105 called an fθ lens (F-theta lens) may be used.

  In the configuration example shown in FIG. 13A, the spot-shaped light is scanned by the galvano scanner 103 or the like, and the irradiation area of the illumination light for recording the image data is moved as indicated by the arrow S1 in FIG. 13A. Yes. Instead of the galvano scanner 103, a resonant scanner or a so-called polygon mirror may be used. For example, a telecentric fθ lens is suitable as the fθ lens.

  Here, the optical modulator 101 is a modulator for converting information into an optical signal. Examples of the optical modulator 101 include an electro-optic modulator (EO modulator), an acousto-optic modulator, an optical switch using a thermo-optic effect, an optical switch using a photonic crystal, and a nonlinear optical effect. The optical switch etc. which were made are mentioned. When an acousto-optic modulator, for example, is applied as the optical modulator 101, the second information recording is also performed as image data, for example, a pattern other than characters and figures by intensity modulation (analog modulation or digital modulation). It is possible to record on the body 12.

  The laser light emitted from the laser light source 91 is controlled by the optical modulator 101, and the second information recording body 12 is sequentially exposed in the form of dots by scanning the spot-like light. Image data such as a barcode can be recorded on the second information recording body 12. In the case where the substrate of the recording medium has a disk shape, the peripheral speed depends on the radius, so that the scanning speed of the spot-like light is preferably adjusted according to the distance from the rotation center.

  FIG. 13B is a schematic diagram illustrating an example of image data recorded in the second information recording medium. In FIG. 13B, illustrations other than the clamping area CL of the recording medium 7 are omitted.

  By scanning the laser light modulated by the light modulator 101 while rotating the substrate and sequentially exposing the second information recording body 12 in a dotted manner, as shown in FIG. Combinations of patterns and the like can also be recorded on the second information recording body 12.

  Thus, by using the angle-selective holographic original plate when recording information on the second information recording body 12, a desired area of the second information recording body 12 can be selectively exposed, as if Image data can be recorded like laser marking.

  FIG. 13C is a schematic diagram illustrating an example of a method for reading image data recorded in the second information recording body as a hologram image.

  In the configuration example shown in FIG. 13A, illumination light for recording image data is incident substantially perpendicular to the main surface of the second information recording body 12. Therefore, when reproducing the image data recorded on the second information recording body 12, for example, substantially perpendicular to the main surface of the second information recording body 12, for example, in the radial direction of the recording medium 7. Accordingly, the second information recording body 12 may be irradiated with a laser beam shaped substantially linearly.

  In this case, the reproduction light related to the image data recorded on the second information recording body 12 is emitted toward the virtual light source VS shown in FIG. 4B. That is, the reproduction light related to the image data recorded on the second information recording body 12 is emitted toward the rotation axis of the recording medium 7 at an angle of 45 ° with respect to the main surface of the second information recording body 12. The Therefore, when the image data recorded on the second information recording body 12 is read by the photodetector, the photodetector may be disposed at the same position as the virtual light source VS shown in FIG. 4B. .

  As described above, in the present disclosure, a recording material such as a photopolymerization type photopolymer is directly disposed on a substrate such as an optical disk. Furthermore, general three-dimensional image data and two-dimensional image data such as a barcode and a serial number are recorded as a hologram image on a recording material arranged directly on a substrate such as an optical disk. That is, a volume hologram is directly formed on a substrate such as an optical disk.

  Therefore, unlike the case where a hologram sticker is attached to a recording medium itself such as an optical disk or a case, it is difficult to easily remove or illegally copy a hologram on which image data is recorded. As described above, according to the present disclosure, it is possible to provide an authentication function and high security to a recording medium such as an optical disk.

  Furthermore, according to the present disclosure, since image data is recorded on a volume hologram formed directly on a substrate such as an optical disk, for example, by recording three-dimensional image data or the like as a hologram image on a recording material. Further, it is possible to improve the design properties of an optical disk or the like. In other words, according to the present disclosure, it is possible to further enhance the commercial value of a recording medium such as an optical disk by giving the recording medium such as an optical disk an added value such as high security and high design.

  Further, for example, according to the present disclosure, information associated with a unique ID for each optical disc can be recorded as a hologram image on the optical disc itself. Therefore, it is possible to provide a new function using information associated with a unique ID for each optical disk, and a recording medium such as an optical disk can be made a recording medium with further excellent applicability.

<2. Second Embodiment>
As described above, in the present disclosure, by appropriately changing the specifications of the original plate, the incident direction of illumination light for reproducing the information recorded on the second information recording body and the recording on the second information recording body are recorded. The emission direction of the reproduction light related to the information thus set can be arbitrarily set.

  In the first embodiment, when the recording medium is illuminated by the illumination light source while the relative positional relationship between the rotation center of the recording medium and the illumination light source is fixed, the rotation of the substrate of the second information recording body is performed. Information was reproduced from the part corresponding to the corner. The second embodiment is different from the first embodiment in that the presence or absence of information reproduction from the entire surface of the second information recording body is switched depending on the rotation angle of the base. In addition, since each member which comprises the recording medium concerning 2nd Embodiment is substantially the same as each member which comprises the recording medium concerning 1st Embodiment, description is abbreviate | omitted below.

[2-1. Outline of recording medium manufacturing method]
First, for example, a case is assumed where information is recorded on the second information recording body by copying a pattern or the like recorded as a hologram image on the transfer portion of the original plate onto the second information recording body.

(2-1-1. Configuration example of the original plate)
14A to 14D are schematic diagrams illustrating a relationship between an incident angle of illumination light for reproducing a hologram image recorded on the transfer unit and an emission angle of reproduction light emitted from the transfer unit.

  In the second embodiment, for example, when the collimated laser beam is applied to the entire upper surface Fs of the transfer unit 63 from a predetermined angular direction, the recorded hologram image is transferred to the transfer unit 63. An original plate 53 configured to be reproduced from the entire surface is used.

  For example, as shown in FIGS. 14A to 14C, it is assumed that green laser light as illumination light is irradiated on the entire surface of the transfer unit 63 at an angle of 45 ° with respect to the entire surface of the upper surface Fs of the transfer unit 63. The light source of the green laser light at this time is, for example, at a position where X = 0, Y> 0, and Z> 0.

  Then, reproduction light relating to the hologram image is emitted from almost all the area of the transfer unit 63. The reproduction light emission direction at this time is set, for example, in the + Z direction, as shown in FIGS. 14A to 14C.

  Therefore, when the transfer part 63 is observed from the upper surface, the recorded hologram image is reproduced from almost all the area of the transfer part 63 as shown in FIG. 14D. FIG. 14D shows a configuration example in which the logo of the recording medium manufacturer according to the second embodiment is recorded on the hologram layer of the transfer section 63 as a reflection type volume hologram. In FIG. 14D, the reproduced hologram image is shown by shading.

(2-1-2. Transfer of Second Information Recorder and Recording of Information on Second Information Recorder)
Also in the second embodiment, the second recording area is formed, for example, by transferring the material constituting the second information recording body from the upper surface of the transfer portion to the clamping area of the substrate. Further, by irradiating the transfer portion and the material constituting the second information recording body transferred to the clamping area of the substrate with laser light, the information recorded in the transfer portion is changed to the second information recording body. Duplicated in information recording medium The second embodiment is different from the first embodiment in that information is recorded on the second information recording body in batches in accordance with the specifications of the original plate.

  15A to 15C are schematic views illustrating an example of a method for manufacturing a recording medium according to the second embodiment.

  When recording information on the second information recording body 12, as shown in FIG. 15A, first, a material constituting the second information recording body 12 is applied to the upper surface Fs of the transfer portion 63. In addition, in order to improve the peelability of the material constituting the second information recording body 12 with respect to the upper surface Fs of the transfer portion 63, the transfer portion 63 is provided with a coat layer as in the case of the first embodiment. .

  Next, an original 53 coated with a material constituting the second information recording body 12 is opposed to the upper surface Fs of the transfer portion 63 with respect to the base body 10 in which the first information recording body 11 is disposed. It is done. Further, the original 53 is pressed against the substrate 10, and the material constituting the second information recording body 12 is brought into close contact with the clamping area CL on the back surface Bs side of the substrate 10.

  Next, as shown in FIG. 15B and FIG. 15C, the parallel light of the green laser that travels in the −Y direction, for example, through the substrate 10 is the material that forms the second information recording body 12 and the transfer unit. 63 is irradiated.

  At this time, the incident angle of the green laser light with respect to the base 10 is set so that the incident angle with respect to the transfer portion 63 is approximately 45 ° in accordance with the specifications of the original 53. Further, the green laser light is collectively irradiated on the entire surface of the material constituting the second information recording body 12. Note that the substrate 10 is not rotated during the green laser light irradiation.

  Due to the irradiation with the green laser light, reproduction light relating to the hologram image recorded in the hologram layer of the transfer portion 63 is emitted from almost the entire surface of the transfer portion 63. Therefore, the reproduction light (object light) from the hologram layer of the transfer unit 63 and the green laser light (reference light) interfere with each other in the second information recording body 12, and the second information recording body 12 Interference patterns are recorded in units of planes. In other words, the hologram image recorded on the hologram layer of the transfer unit 63 is duplicated on the second information recording body 12 in a unit of plane.

  After the replication of the hologram image recorded on the hologram layer of the transfer unit 63 with respect to the second information recording body 12 is completed, the material constituting the second information recording body 12 is peeled from the upper surface Fs of the transfer unit 63. The Therefore, the material constituting the second information recording body 12 is transferred to the clamping area CL of the base 10.

  After the transfer of the material constituting the second information recording body 12 to the clamping area CL of the substrate 10, ultraviolet rays for fixing the recorded image to the second information recording body 12 as necessary. Post-processing such as irradiation and heating is performed. Further, the louvers 15 are arranged on the surface of the second information recording body 12 and a protective layer is formed as necessary. As described above, the recording medium according to the second embodiment is obtained.

  In the above-described example, in recording information on the second information recording body 12, the entire surface of the second information recording body 12 arranged in the clamping area CL is exposed in a batch unit. Instead of exposing the entire surface of the second information recording body 12 arranged in the clamping area CL in units of planes, the second information recording body 12 is exposed in units of lines or points. Also good.

  For example, the laser beam shaped in a substantially linear shape along the Y-axis direction is scanned along the X-axis direction so that the irradiation region becomes longer than the diameter of the clamping area CL, thereby the second The entire surface of the information recording body 12 may be sequentially exposed. Alternatively, for example, the entire surface of the second information recording body 12 may be exposed by scanning a laser beam formed in a dot shape.

[2-2. Reproduction of information from second information recording body]
FIG. 16A is a diagram illustrating a coordinate system set for a recording medium and a light source. 16B to 16D are schematic diagrams illustrating examples of hologram images observed from the recording medium when the recording medium is rotated in a state where the relative positional relationship between the center of the recording medium and the light source is fixed. 16B to 16D, illustrations other than the clamping area CL of the recording medium 8 are omitted.

  When reproducing a hologram image from the second recording region R2 of the recording medium 8 according to the second embodiment, a light source of illumination light is arranged in the direction of (φ, θ) = (90 °, 45 °). Set to 16B to 16D show a state in which the recording medium 8 is illuminated with white light from the light source 84 arranged in the direction of (φ, θ) = (90 °, 45 °). At this time, the angle formed by the surface Ts of the recording medium 8 and the optical axis of the illumination light is 45 °.

  In recording information on the second information recording body 12 of the recording medium 8, when illumination light is irradiated at an angle of 45 ° with respect to the entire upper surface Fs of the transfer unit 63, almost all of the transfer unit 63 is recorded. From the area, the original 53 from which the hologram image is reproduced was used. Accordingly, the recording medium 8 including the second information recording body 12 in which the hologram image is duplicated from the original 53 is similarly irradiated with illumination light at an angle of 45 ° with respect to the entire surface of the second information recording body 12. Sometimes, a hologram image is reproduced from almost the entire second recording area R2.

  That is, for example, as shown in FIGS. 16B to 16D, when the recording medium 8 is rotated under illumination light from a predetermined angular direction to change the rotation angle α, the rotation angle α becomes a certain value. The hologram image is reproduced from almost all of the second recording area R2 only in the vicinity. In this example, the relative positional relationship between the optical system and the second information recording body 12 in the process of recording information on the second information recording body 12, and the relative positions of the light source 84 and the recording medium 8 that illuminate the recording medium 8. When the relationship becomes almost equal, the hologram image is reproduced. Therefore, the state shown in FIG. 16C is a state where α≈0 °.

[2-3. Recording of image data using angle-selective holographic master]
(2-3-1. Angle-selective holographic master)
Also in the second embodiment, as in the first embodiment, by applying the angle-selective holographic original plate to the transfer portion of the original plate, the second information recording medium can be used as a reflection hologram. Image data can be recorded.

  FIG. 17A is a schematic diagram illustrating another example of a method for manufacturing an angle-selective holographic original plate applicable as a transfer portion.

  For example, as shown in FIG. 17A, mutually coherent laser beams are incident on almost the entire surface of the hologram layer of the transfer section 64 from the respective main surfaces of the hologram layer. At this time, for example, the collimated laser light (corresponding to the reference light) traveling in the −Y direction so that the angle formed by the incident surface and the optical axis is 45 ° is transferred to the transfer unit 64. Is incident on one of the principal surfaces. Further, for example, collimated laser light (corresponding to object light) so that the incident angle with respect to the transfer unit 64 is 180 ° is applied to the other main surface side of the main surface of the transfer unit 64. Make it incident.

  The two laser beams incident from the respective main surfaces of the transfer unit 64 interfere with each other in the hologram layer of the transfer unit 64. Therefore, the transfer unit 64 becomes a holographic original plate in which a hologram for uniformly diffracting light incident from a predetermined direction in a specific direction is uniformly recorded.

  FIG. 17B is a schematic diagram illustrating a relationship between an incident angle of illumination light for reproducing a hologram recorded on the hologram layer of the transfer portion and an emission angle of reproduction light emitted from the transfer portion.

  As shown in FIG. 17B, the transfer unit 64 is illuminated with collimated laser light traveling in the −Y direction so that the angle formed by the upper surface Fs of the transfer unit 64 and the optical axis is 45 °. Suppose that Then, the reproduction light is emitted in the + Z direction.

  FIG. 17C shows a case where the angle formed by the upper surface of the transfer portion and the optical axis is 45 ° and the transfer portion illuminated with collimated laser light traveling in the −Y direction is observed. It is the schematic which shows an example of the hologram observed from.

  When observing the upper surface Fs of the transfer part 64 provided in the original 54 under illumination from a predetermined direction, the observer of the transfer part 64 confirms the hologram recorded in the hologram layer of the transfer part 64. Can do. That is, for example, when a hologram is recorded using a green laser, the entire surface of the transfer unit 64 looks green under illumination of green laser light from a predetermined direction. In FIG. 17C, a region that appears green when the transfer portion 64 is observed is shown by shading.

  In this example, when the transfer unit 64 is rotated in a plane parallel to the main surface of the transfer unit 64 while the relative positional relationship between the center of the transfer unit 64 and the light source of the green laser light is fixed, the transfer unit 64 is rotated. The hologram recorded in the 64 hologram layers is not confirmed.

  Next, a transfer unit 64 configured as an angle-selective holographic master is disposed at a position close to the second information recording body 12. For example, the second information is recorded in the same manner as in the first embodiment. A desired area of the recording body 12 is selectively exposed. By using the angle-selective holographic master when recording information on the second information recording body 12, the second information recording body causes interference only in the vicinity of a desired area in the second information recording body 12. Image data can be recorded directly on the recording body 12.

  FIG. 17D and FIG. 17E are schematic diagrams illustrating a configuration example of a light source for recording image data on the second information recording body.

  The optical system 89 shown in FIGS. 17D and 17E includes, for example, a light modulation element 107 disposed between the beam expander 93 and the base 10 of the recording medium. In FIG. 17D and FIG. 17E, the imaging optical system is not shown in order to avoid making the figure complicated.

  The laser light emitted from the laser light source 91 is expanded by the beam expander 93 and then enters the light modulation element 107. The light modulation element 107 is, for example, a liquid crystal panel, and an image relating to image data to be recorded as a hologram image on the second information recording body 12 is displayed on the screen of the liquid crystal panel. Accordingly, the laser light incident on the light modulation element 107 is collectively modulated by the light modulation element 107 in units of planes.

  As shown in FIGS. 17D and 17E, the modulated laser light traveling in the −Y direction is irradiated to the transfer portion 64 at an angle of 45 °. Then, the light that has passed through the material constituting the second information recording body 12 and reached the hologram layer of the transfer unit 64 is diffracted by the transfer unit 64 configured as an angle selective holographic master, and in the + Z direction. Then, the light is emitted from the transfer unit 64. The modulated laser beam and the light diffracted by the transfer unit 64 configured as an angle selective holographic master and emitted toward the material constituting the second information recording body 12 are the second information recording body. 12 interferes. Therefore, an interference pattern related to image data is recorded on the second information recording body 12.

  Instead of modulating the laser light by the light modulation element 107, a mask having an opening of a desired shape may be disposed between the optical system and the second information recording body 12. In this case, for example, a desired pattern can be recorded on the second information recording body 12 by using a mask having an opening of a desired shape.

  It is assumed that the recording medium after recording the image data on the second information recording body 12 is observed while rotating the recording medium in a state where the relative positional relationship between the center of the recording medium and the light source of the illumination light is fixed. . Then, similarly to the transfer unit 64, the hologram image recorded on the second information recording body 12 may be visible or invisible depending on the rotation angle of the recording medium. Specifically, in the process of recording information on the second information recording body 12, the relative positional relationship between the optical system 89 and the second information recording body 12, and the relative positions of the light source and the recording medium that illuminate the recording medium When the relationship becomes almost equal, the hologram image is reproduced.

  As described above, according to the present disclosure, a volume hologram can be integrally formed on a substrate such as an optical disk. In addition, a hologram recorded on the original plate is prepared by arranging the second information recording body on a substrate such as an optical disk and exposing the second information recording body using the original on which the hologram image has been recorded in advance. The image can be duplicated on the second information recording body. Furthermore, by applying an angle selective holographic original plate as a transfer portion of the original plate, arbitrary image data can be recorded as a hologram image on the second information recording body.

  In the present disclosure, the hologram image recorded by copying from the original plate or by selective exposure is recorded on the main body of a recording medium such as an optical disk instead of a packing case. Therefore, the recording medium according to the present disclosure is copied. Can be a difficult recording medium. In addition, by recording information associated with an ID unique to each optical disc on a volume hologram on a substrate such as an optical disc, an ID printed paper enclosed in a packing case or the like Can be made unnecessary.

<3. Modification>
The preferred embodiments have been described above, but the preferred specific examples are not limited to the above-described examples, and various modifications can be made.

  In the above-described embodiment, the example in which the material constituting the second information recording body is arranged in the clamping area such as the optical disc has been shown. However, the material constituting the second information recording body is other than the clamping area. It may be arranged at a location.

  In the above-described embodiment, the example in which the material constituting the second information recording body is arranged on the back surface side of the base body is shown. However, the material constituting the second information recording body may be You may arrange | position inside a base | substrate.

  18A and 18B are diagrams showing a configuration example of a recording medium in which a second information recording body is arranged on the surface side of the substrate.

  FIG. 18A shows a configuration example of the recording medium 9a in which the louver 15, the second information recording body 12, and the protective layer 17 are sequentially laminated on the clamping area CL on the surface Ts side of the substrate 10. In FIG. 18B, the second information recording body 12 and the protective layer 17 are sequentially laminated on the clamping area CL on the surface Ts side of the base body 10, and the louver is placed on the clamping area CL on the back surface Bs side of the base body 10. 15 shows a configuration example of a recording medium 9b in which 15 is arranged.

  The protective layer 17 is a layer made of a transparent resin, for example. The protective layer 17 is provided as necessary for the purpose of protecting the second information recording body 12.

  As shown in FIG. 18A and FIG. 18B, in response to the second information recording body 12 being disposed on the main surface on the surface Ts side of the substrate 10, the recording medium 9a and the recording medium 9b A recording area R2 is provided. In this case, the information recorded on the second information recording body 12 is observed or read through the protective layer 17 from the surface Ts side.

  In the above-described embodiment, the information recorded on the second information recording body 12 has been described as being read from the surface Ts side by, for example, a dedicated reading device, but is recorded on the second information recording body 12. The information may be read from the back surface Bs side.

  18C and 18D are schematic diagrams illustrating an example of a method for reading information from the second information recording body.

  FIG. 18C shows an example of a recording medium 9c configured such that the information recorded on the first information recording body 11 and the information recorded on the second information recording body 12 are both read from the back surface Bs side. ing. A recording medium 9c shown in FIG. 18C has a configuration in which the second information recording body 12 and the louver 15 are sequentially laminated on the clamping area CL on the surface Ts side of the base 10.

  When reproducing the information recorded in the second information recording body 12 arranged in the clamping area CL of the recording medium 9c, as shown in FIG. 18C, the second information recording body 12 is determined in advance. Illumination light IL is irradiated from a certain angle direction. As shown in FIG. 18C, the information recorded in the second information recording body 12 is reproduced by irradiating the illumination light IL from a predetermined angular direction. The reproduction light DL diffracted by the second information recording body 12 is emitted from the second information recording body 12 toward the back surface Bs side of the recording medium 9c. That is, in the configuration shown in FIG. 18C, the hologram image reproduced from the second information recording body 12 is read from the back surface Bs side in the same manner as the information reproduced from the first information recording body 11.

  In the recording medium 9d shown in FIG. 18D, the louver 15 is disposed on the clamping area CL on the front surface Ts side of the substrate 10, and the second information recording body is disposed on the clamping area CL on the back surface Bs side of the substrate 10. 12 and the protective layer 17 are laminated in order.

  When reproducing the information recorded in the second information recording body 12 arranged in the clamping area CL of the recording medium 9d, as shown in FIG. 18D, the second information recording body 12 is determined in advance. Illumination light IL is irradiated from a certain angle direction. In this case, the illumination light IL is applied to the second information recording body 12 through the protective layer 17, and the hologram image reproduced from the second information recording body 12 is read from the back surface Bs side.

  Further, for example, a plurality of original plates may be prepared and used by exchanging them for each disk.

  For example, the manufacturer of the recording medium, a one-dimensional barcode, a two-dimensional barcode, etc. can be recorded on the second information recording body as the image data.

  Note that the configurations, methods, shapes, processes, materials, numerical values, and the like given in the above-described embodiments are merely examples, and different configurations, methods, shapes, processes, materials, numerical values, and the like are used as necessary. Also good. The configurations, methods, shapes, processes, materials, numerical values, and the like of the above-described embodiments can be combined with each other without departing from the gist of the present disclosure.

For example, this indication can also take the following composition.
(1)
A base body having a rotationally symmetric shape;
A first information recording body disposed inside the substrate;
A second information recording body disposed on the substrate,
When illuminated by the illumination light source in a state where the relative positional relationship between the rotation center and the illumination light source is fixed, information is reproduced from the portion corresponding to the rotation angle of the substrate in the second information recording body. Recording medium.
(2)
The recording medium according to (1), wherein the second information recording body is an information recording body on which information is recorded as refractive index modulation.
(3)
The recording medium according to (1) or (2), wherein the information recorded on the second information recording body is in the form of a bar code arranged in an annular shape.
(4)
The recording medium according to any one of (1) to (3), wherein the information recorded on the second information recording body is information associated with the information recorded on the first information recording body. .
(5)
The information recorded on the second information recording body is information required for reproducing the information recorded on the first information recording body, according to any one of (1) to (4). Recording media.
(6)
The recording medium according to any one of (1) to (5), wherein the information recorded on the second information recording body is information required for recording information on the first information recording body. .
(7)
The recording medium according to any one of (1) to (6), wherein the first information recording body is an information recording body on which information is recorded as modulation of reflection characteristics with respect to incident light.
(8)
The first information recording body has an annular shape;
The recording medium according to any one of (1) to (7), wherein the second information recording body is disposed on an inner side than an inner diameter of the first information recording body having an annular shape.
(9)
The recording medium according to any one of (1) to (8), wherein the second information recording body is disposed in a recess provided in the base.

1, 2, 3, 5, 6, 7, 8, 9 ... recording medium 10, 13 ... base 11 ... first information recording body 12 ... second information recording body 51, 52 , 53, 54... Master 61, 62, 63, 64... Transfer portion CL... Clamping area R1... First recording area R2.

Claims (9)

A base body having a rotationally symmetric shape;
A first information recording body disposed inside the substrate;
A second information recording body disposed on the substrate,
When illuminated by the illumination light source in a state where the relative positional relationship between the rotation center and the illumination light source is fixed, information is reproduced from the portion corresponding to the rotation angle of the substrate in the second information recording body. Recording medium.   The recording medium according to claim 1, wherein the second information recording body is an information recording body on which information is recorded as a refractive index modulation.   The recording medium according to claim 1, wherein the information recorded on the second information recording body is in the form of a bar code arranged in an annular shape.   The recording medium according to claim 1, wherein the information recorded on the second information recording body is information associated with information recorded on the first information recording body.   The recording medium according to claim 1, wherein the information recorded on the second information recording body is information necessary for reproducing the information recorded on the first information recording body.   The recording medium according to claim 1, wherein the information recorded on the second information recording body is information required for recording information on the first information recording body.   The recording medium according to claim 1, wherein the first information recording body is an information recording body on which information is recorded as modulation of reflection characteristics with respect to incident light. The first information recording body has an annular shape;
The recording medium according to claim 1, wherein the second information recording body is disposed on the inner side of an inner diameter of the first information recording body which is formed in an annular shape.   The recording medium according to claim 1, wherein the second information recording body is disposed in a recess provided in the base.

Images