Abstract: A hologram reproduction apparatus and method is disclosed wherein positioning between reproduction reference light and a hologram recording medium can be performed accurately. Reference light is irradiated upon the medium recorded by angle multiple recording, and reproduction light generated from the medium is received by an image pickup apparatus to reproduce data. Thereupon, projection information of light which cannot pass through an iris but is projected on the iris is detected by an optical detector. A position control section detects a positional displacement of the medium based on projection state information on the inner side of a projection region of reproduction light generated from an adjacent recording area to the recording area of a reproduction target from within the detection information and controls a drive mechanism to move the medium so as to eliminate the positional displacement.

Abstract: A hologram recording apparatus and method is disclosed by which the recording density in hologram recording by shift multiple hologram recording which uses reference light of a spherical wave or by speckle multiple hologram recording which uses randomly modulated reference light can be enhanced. When interference fringes of a reference light beam and a signal light beam, for example, of spherical waves are multiple recorded in accordance with a shift multiple recording method in a hologram medium, every time a hologram train to be produced successively by shift multiplex recording the interference fringes in the hologram medium is changed, the incidence angle at which the reference light beam enters the hologram medium is changed to a different value so that a predetermined condition may be satisfied. Then, a next track is recorded using the reference light beam.

Abstract: In recording of an interference fringe of a reference beam and a signal beam in a hologram recording medium, at the time of multiple recording of holograms in the same recording region by varying the angle of incidence of the reference beam on the hologram recording medium, the angular pitch of the incidence angle of the reference beam is varied according to the incidence angle of the reference beam in the manner of ??1, ??2, . . . , ??m?1, and is thereby set to a minimum in such a range as not to worsen crosstalk. This makes it possible to increase the degree of multiplexing when the movable angle of the reference beam is the same, and to narrow the movable angle of the reference beam when the degree of multiplexing is the same, as compared with the related art.

Abstract: A hologram duplicating apparatus (10) includes a first optical system (30) for carrying out exposure recording of holographic stereogram image on a recording medium for hologram to produce an original H1, a second optical system (60) for carrying out exposure recording of image recorded on the original H1 on a recording medium for hologram disposed at a predetermined distance from the original H1 by using diffracted light obtained by illuminating the original H1 to produce intermediate hologram H2, and a third optical system (70) for carrying out exposure recording of image recorded on the intermediate hologram H2 on a recording medium for hologram disposed at a predetermined distance from the intermediate hologram H2 by using diffracted light obtained by illuminating the intermediate hologram H2 to produce edge lit hologram H3.

Abstract: Between a spatial beam modulator for modulating an object beam and a one-dimensional diffuser plate for diffusing the object beam modulated by the spatial beam modulator in a one-dimensional direction, there is arranged an object projection optical system for processing the object beam modulated by the spatial beam modulator in such a manner that, in the one-dimensional direction of the one-dimensional diffuser plate, images displayed by the spatial beam modulator are formed on the one-dimensional diffuser plate, and, in a direction substantially orthogonal to the one-dimensional direction, the object beam is condensed onto a hologram recording medium. In the one-dimensional direction of the one-dimensional diffuser plate, the images displayed by the spatial beam modulator are formed on the one-dimensional diffuser plate, whereby blurring of the images with the one-dimensional direction as a non-parallactic direction can be suppressed.

Abstract: The present invention provides a hologram apparatus for recording interference fringes formed from reference light and signal light optically spatially modulated by a spatial light modulator on a hologram recording material or picking up an image of reproduction signal light produced by irradiating illumination reproduction light on the hologram recording material by means of an image pickup device to obtain a reproduction image signal. The hologram apparatus includes a matching data acquisition section, an arithmetic operation section, and a positioning control section. The matching data acquisition section directly picks up an image of the signal light optically spatially modulated with a pixel matching pattern displayed on the spatial light modulator by means of the image pickup device to obtain a reproduction image signal. The arithmetic operation section performs predetermined arithmetic operation using a luminance value of the reproduction image signal.

Abstract: A rise in temperature of magneto coils can be suppressed, thereby improving the electrical efficiency, service life and reliability thereof. A flywheel (3) has a cylindrical portion (4), and is rotatable about an axis of rotation A-A. A plurality of magnets (7) are mounted on an inner peripheral surface of the flywheel (3) so as to rotate therewith. A stator core (10) has a plurality of teeth (12) protruded outwardly in a diametral direction, and is disposed in opposition to the magnets (7). Conductive wires are wound around the teeth (12), respectively, to form magneto coils (11). The stator core (10) has a laminated core (15) formed of a plurality of magnetic sheet steel plates laminated one over another, and a pair of end plates (16, 17) disposed so as to sandwich opposite side surfaces of the laminated core (15). At least one of the pair of end plates (16, 17) is made of aluminum whose heat radiation is higher than the magnetic sheet steel plates.

Abstract: The present invention provides a hologram apparatus for recording an interference fringe of a signal beam and a reference beam having a speckle pattern in a recording area of a hologram recording material. The hologram apparatus includes a speckle pattern generating unit for generating the speckle pattern so that the speckle pattern is different in form in the track direction and the cross-track direction of the recording area. With this configuration, it is possible to perform recording under an increased tolerance in the cross-track direction while securing the shift selectivity necessary in the track direction, and, hence, to easily and stably perform the tracking servo at the time of reproduction.

Abstract: At the time of varying the angle of a scan mirror for varying the angle of incidence of a reference beam on a hologram recording material, the angle of a slit is also varied in conjunction, whereby the beam diameter of the reference beam is varied by the slit so that the irradiation range on the hologram recording material will be constant without being varied according to the variation in the incidence angle of the reference beam. This ensures that the area of irradiation of the hologram recording material with the reference beam can always be kept constant, even when the incidence angle of the reference beam is varied at the time of recording holograms by the angle multiplex recording system.

Abstract: A hologram duplication method is disclosed which makes it easy to duplicate a large number of holograms from a volume-recorded hologram, particularly from a hologram recorded in a recording medium of the disk type or the card type. N card type master recording media are prepared, and data pages are individually recorded on the N disk type master recording media without being multiplexed by changing the angle of a reference light beam among the N disk type master recording media. Thereafter, the data page recorded on each of the disk type master recording media is recorded on a common disk type duplication recording medium so that the data pages are N-multiplex recorded finally on the disk type duplication recording medium.

Abstract: An optical member 7 is bonded, at its rear side 7b, to a holographic stereogram 6. The front side 7a of the optical member 7 consists of parallel triangular prisms. Illumination light 9 is applied to the front surface 7a of the optical member 7 at a predetermined angle of, for example, 60°. The optical member 7 is made of, for example, optical glass or transparent plastic. Each triangular prism has an incidence surface 8, to which the illumination light is applied at right angles. The illumination light is applied to the interface 22 between the optical member 7 and the holographic stereogram 6, at an incidence angle ? of, for example, 60°, thereby to suppress surface reflection of the illumination light 9 at the interface 22.

Abstract: An optical member 7 is bonded, at its rear side 7b, to a holographic stereogram 6. The front side 7a of the optical member 7 consists of parallel triangular prisms. Illumination light 9 is applied to the front surface 7a of the optical member 7 at a predetermined angle of, for example, 60°. The optical member 7 is made of, for example, optical glass or transparent plastic. Each triangular prism has an incidence surface 8, to which the illumination light is applied at right angles. The illumination light is applied to the interface 22 between the optical member 7 and the holographic stereogram 6, at an incidence angle ? of, for example, 60°, thereby to suppress surface reflection of the illumination light 9 at the interface 22.

Abstract: An optical member 7 is bonded, at its rear side 7b, to a holographic stereogram 6. The front side 7a of the optical member 7 consists of parallel triangular prisms. Illumination light 9 is applied to the front surface 7a of the optical member 7 at a predetermined angle of, for example, 60°. The optical member 7 is made of, for example, optical glass or transparent plastic. Each triangular prism has an incidence surface 8, to which the illumination light is applied at right angles. The illumination light is applied to the interface 22 between the optical member 7 and the holographic stereogram 6, at an incidence angle ? of, for example, 60°, thereby to suppress surface reflection of the illumination light 9 at the interface 22.

Abstract: An inline type speckle multiplexed hologram recording apparatus and method is disclosed which can condense signal light and reference light in a sufficiently overlapping relationship with each other on a hologram recording medium without using a lens having a large aperture and a wide angle of view. A signal light region and a reference light region are displayed on a spatial light modulator, and laser light is intensity modulated with recording data displayed in the signal light region to produce signal light while the laser light having passed through the reference light region is used as reference light. The signal light and the reference light are diffused by a diffuser and then condensed in an overlapping relationship with each other on a hologram recording medium by a lens such that interference fringes produced thereby are recorded in the hologram recording medium.

Abstract: A magnetoelectric generator includes a bowl-like flywheel (3) having a bottom portion (6) formed with ventilation holes (20), a plurality of permanent magnets (7) secured to an inner circumferential surface of the flywheel (3), a stator core (10) disposed within the flywheel (3) and having peripheral side surfaces facing the permanent magnets (7), and a coil assembly (11) implemented by winding an electric conductor on the core (10). Electricity is induced in the coil assembly (11) by AC magnetic field produced by rotating the flywheel (3). A peripheral edge portion of each ventilation hole (20) is formed with a projecting portion (21) by plastic deformation, which protrudes toward the coil assembly (11) for producing turbulent air flows internally of the flywheel (3) upon rotation of the flywheel (3).

Abstract: A rise in temperature of magneto coils can be suppressed, thereby improving the electrical efficiency, service life and reliability thereof. A flywheel (3) has a cylindrical portion (4), and is rotatable about an axis of rotation A—A. A plurality of magnets (7) are mounted on an inner peripheral surface of the flywheel (3) so as to rotate therewith. A stator core (10) has a plurality of teeth (12) protruded outwardly in a diametral direction, and is disposed in opposition to the magnets (7). Conductive wires are wound around the teeth (12), respectively, to form magneto coils (11). The stator core (10) has a laminated core (15) formed of a plurality of magnetic sheet steel plates laminated one over another, and a pair of end plates (16, 17) disposed so as to sandwich opposite side surfaces of the laminated core (15). At least one of the pair of end plates (16, 17) is made of aluminum whose heat radiation is higher than the magnetic sheet steel plates.

Abstract: A hologram recording medium is disclosed which can prevent sensitization of a region thereof other than a data recording region thereby to prevent deterioration of a characteristic of the hologram recording medium. The hologram recording medium includes partition members for partitioning a recording material. Upon recording, unnecessary light generated when signal light and reference light enter the recording material is blocked from propagating in the recording material by the partition members and cannot advance into adjacent partitions. Therefore, unnecessary sensitization of the recording material by the unnecessary light can be prevented, and particularly, decrease of the recording capacity can be prevented. Consequently, the performance of a hologram recording and reproduction apparatus which adopts, for example, a multiplex recording system can be exhibited fully.

Abstract: A method and apparatus is disclosed which can reproduce multi-value data with high reproducibility from a hologram recording medium having data recorded in multi-values therein and can reduce the error rate of reproduction data. A reference gradation pattern is recorded in a medium, and luminance unevenness of a gradation pattern obtained by reproducing the gradation pattern is corrected. A gamma characteristic of the medium is determined based on the reproduction gradation pattern, and a modulation pattern produced using easily separable luminance values determined based on the gamma characteristic is displayed on a spatial light modulator to record data in multi-values into the medium. Thereupon, the data are oversampled and recorded, and a block of the reproduced data is decoded depending upon a sequence of relative luminance levels of pixels in the block to decode the entire reproduced multi-value data.

Abstract: An optical member 7 is bonded, at its rear side 7b, to a holographic stereogram 6. The front side 7a of the optical member 7 consists of parallel triangular prisms. Illumination light 9 is applied to the front surface 7a of the optical member 7 at a predetermined angle of, for example, 60°. The optical member 7 is made of, for example, optical glass or transparent plastic. Each triangular prism has an incidence surface 8, to which the illumination light is applied at right angles. The illumination light is applied to the interface 22 between the optical member 7 and the holographic stereogram 6, at an incidence angle ? of, for example, 60°, thereby to suppress surface reflection of the illumination light 9 at the interface 22.

Abstract: An optical member 7 is bonded, at its rear side 7b, to a holographic stereogram 6. The front side 7a of the optical member 7 consists of parallel triangular prisms. Illumination light 9 is applied to the front surface 7a of the optical member 7 at a predetermined angle of, for example, 60°. The optical member 7 is made of, for example, optical glass or transparent plastic. Each triangular prism has an incidence surface 8, to which the illumination light is applied at right angles. The illumination light is applied to the interface 22 between the optical member 7 and the holographic stereogram 6, at an incidence angle ? of, for example, 60°, thereby to suppress surface reflection of the illumination light 9 at the interface 22.