HOLOGRAM RECORDING MEDIUM AND HOLOGRAM RECORDING/REPRODUCTION DEVICE
A hologram recording medium has a substrate and a hologram recording layer into or from which information is recorded or reproduced by a hologram, and a concavo-convex pattern having a reflection layer that transmits hologram recording/reproducing light and reflects light having a longer wavelength than the hologram recording/reproducing light is formed inside the hologram recording medium.
1 . A hologram recording medium having a substrate and a hologram recording layer into or from which information is recorded or reproduced by a hologram, characterized in that:
a concavo-convex pattern is formed inside the hologram recording medium; and
the concavo-convex pattern has a reflection layer that transmits hologram recording/reproducing light and reflects light having a longer wavelength than the hologram recording/reproducing light.
2 . The hologram recording medium according to claim 1 , wherein:
the concavo-convex pattern is formed at a position in a range of 0.55 mm to 0.65 mm both inclusive or a position in a range of 1.1 mm to 1.3 mm both inclusive from a surface of one side of the hologram recording medium.
3 . The hologram recording medium according to claim 1 , wherein:
the hologram recording layer is held between two substrates, and at least one of the substrates contains a material that absorbs light having a shorter wavelength than the hologram recording/reproducing light.
4 . The hologram recording medium according to claim 1 , wherein:
the hologram recording medium has an approximate symmetric structure in a thickness direction about the hologram recording layer.
5 . A hologram recording medium having a substrate and a hologram recording layer into or from which information is recorded or reproduced by a hologram, characterized in that:
a concavo-convex pattern detected by light having a longer wavelength than hologram recording/reproducing light is formed on a surface and/or in an inside of the hologram recording medium; and
a pitch of the concavo-convex pattern is smaller than a distance over which the hologram recording medium and/or an optical system is moved to an adjacent hologram information page on a medium surface of the hologram recording medium during recording or reproduction of the hologram.
6 . A hologram recording medium having a substrate and a hologram recording layer into or from which information is recorded or reproduced by a hologram, characterized in that:
the hologram recording layer has a hologram fixing portion in an inside thereof that transmits hologram recording/reproducing light and suppresses a change in shape of the hologram recording layer.
7 . The hologram recording medium according to claim 6 , wherein:
the hologram fixing portion has a layer structure.
8 . The hologram recording medium according to claim 6 , wherein:
the hologram recording layer is held between two opposing substrates.
9 . The hologram recording medium according to claim 8 , wherein:
the hologram fixing portion has a layer structure, and the hologram recording medium has an approximate symmetric structure in a thickness direction about the hologram fixing portion.
10 . The hologram recording medium according to claim 6 , wherein:
the hologram fixing portion is made of at least one kind selected from the group of a resin material, a glass material, and hologram media.
11 . The hologram recording medium according to claim 6 , wherein:
a concavo-convex pattern is formed inside the hologram recording medium, and the concavo-convex pattern has a reflection layer that transmits the hologram recording/reproducing light and reflects light having a longer wavelength than the hologram recording/reproducing light.
12 . The hologram recording medium according to claim 11 , wherein:
the concavo-convex pattern is formed inside the substrate.
13 . The hologram recording medium according to claim 11 , wherein:
the hologram fixing portion has a layer structure and the concavo-convex pattern is formed inside the hologram fixing portion.
14 . The hologram recording medium according to claim 11 , wherein:
the concavo-convex pattern is formed at a position in a range of 0.55 mm to 0.65 mm both inclusive or a position in a range of 1.1 mm to 1.3 mm both inclusive from a surface of one side of the hologram recording medium.
15 . The hologram recording medium according to claim 11 , wherein:
position information and contents information are recorded in the concavo-convex pattern.
16 . The hologram recording medium according to claim 11 , wherein:
a pitch of the concavo-convex pattern is smaller than a distance over which the hologram recording medium and/or an optical system is moved to an adjacent hologram information page on a medium surface of the hologram recording medium during recording or reproduction of the hologram.
17 . The hologram recording medium according to claim 6 , wherein:
the substrate contains a material that absorbs light having a shorter wavelength than the hologram recording/reproducing light.
18 . A hologram recording medium having a substrate and a hologram recording layer into or from which information is recorded or reproduced by a hologram, characterized in that:
a concavo-convex pattern detected by light having a longer wavelength than hologram recording/reproducing light is formed inside the hologram recording medium; and
position information and contents information are recorded in the concavo-convex pattern.
19 . A hologram recording/reproduction device that records or reproduces information by a hologram into or from a hologram recording medium having a concavo-convex pattern in an inside thereof, characterized by comprising:
a first light source that emits hologram recording/reproducing light;
a second light source that emits position detecting light having a longer wavelength than the hologram recording/reproducing light; and
a detection portion that reproduces position information and contents information recorded in the concavo-convex pattern by detecting reflected light of the position detecting light emitted from the second light source and collected on the concavo-convex pattern.