Pioneer Corporation

Yoshihisa Itoh

Satoru Tanaka

Hajime Matsushita

Yoshihisa Kubota

Hideki Hatano

Akihiro Tachibana

Tomomitsu Kouno

Kazuo Kuroda

Satoshi Sugiura

Takashi Yamaji

Shuuichi Yanagisawa

Masakazu Ogasawara

Michikazu Hashimoto

Fumitaka Kotaka

Michio Sakano

Hajime Matsushia

A holographic recording and reproducing apparatus comprises: a pickup for moving an objective lens that focuses a coherent light beam along a recording track on a holographic recording medium and for detecting reflected light from the recording track to perform focus- and tracking-servo control; a relative velocity determination unit for determining a relative velocity of a converging position of the objective lens with respect to the holographic recording medium; a driving unit for changing a relative position of the objective lens with respect to an optical path of the coherent light beam so as to make the relative velocity fall within a predetermined range at least during a predetermined period; and a control unit for performing recording or reproduction for a recording layer during the predetermined period. The holographic recording medium includes a plurality of markers used for positioning an optical interference pattern of the coherent light beam.

Holographic recording/reproducing apparatus having relative speed controller and method

A hologram recording apparatus () includes a record angle change device () capable of relatively changing the record angle of a hologram recording medium () relative to signal light (L) and reference light (L); and a control device (). The control device sets a record angle for recording a specific angle record plane as a standard record angle among a plurality of angle record planes on the hologram recording medium. Furthermore, the control device controls the record angle change device so as to change and fix the record angle after then by a predetermined angle from the set standard record angle.

Angle-multiplexing hologram recording device, method, hologram reproduction device, and method

A hologram record apparatus () includes a parameter set device (), a move device (), and a control device (). The parameter set device () modifies parameters for multiple recordings such as a record angle and a focal depth in relation to at least one of signal light (L) and reference light (L) and can fix the parameters. The move device () relatively moves the focus position of the signal light and the reference light in the direction along the record surface of a hologram record medium. The control device () performs control so that the parameter for the last recording used for recording at the m-th focus position is used as the parameter for the first recording at the m+1-th focus position.

Multiplex recording type hologram recording device, method, hologram reproduction device, and method

A spatial light modulator, in which light modulation elements are arranged in a same plane. In the spatial light modulator, a plurality of the light modulation elements are arranged such that there are at least two periods of periodic structure corresponding to an arrangement of the light modulation elements in an arbitrary direction in the plane where the light modulation elements are arranged.

Spatial optical modulator

An example recording apparatus includes a pulse oscillation laser, a half mirror for splitting the pulse oscillation light of the laser into a signal light and a reference light, an optical shutter disposed in the optical path of the signal light, a beam expander for converting the signal light into a light beam of a predetermined diameter, a spatial modulator for modulating the recording data into two-dimensional image information, a Fourier Transform lens for introducing the signal light modulated by the spatial modulator onto a recording medium, mirrors for introducing the reference light onto the recording medium with a predetermined angle, a system control unit, a laser driver, a system controller, a recording medium drive mechanism, a modulator driver, a data input unit, and a data processing unit.

Recording device, reproduction device, and recording/reproduction device

A hologram record apparatus () includes a spatial light modulator () and a control device (). The spatial light modulator () is arranged on an optical path of signal light (L) and divided into a plurality of cell blocks () arranged in a matrix. Each of the cell blocks () is further divided into a plurality of cells () arranged in a matrix. The spatial light modulator () can perform modulation on the cell basis. The control device () controls the spatial light modulator so as to modulate the signal light according to a plurality of record information sets to be recorded on a hologram record medium (). Pluralities of modulation units () existing in the same cell block are not made into identical patterns. Since a plurality of cell blocks having a large pitch as compared to the pixel pitch are simultaneously or successively turned on/off, it is possible to reduce the distance between the zeroth-order light and the higher-order light.

Hologram recording device and hologram reproduction device

A hologram recording medium is a hologram recording medium which is irradiated with light for recording information therein or reproducing information therefrom. The hologram recording medium has a recording layer made of a photo-sensitive material capable of preserving an optical interference pattern, a reflective layer disposed on one side of the recording layer opposite to the side on which an light beam impinges, and a quarter wavelength plate interposed between the recording layer and the reflective layer.

Hologram recording medium and recording and reproducing system

A hologram recording and reproducing system having compatibility has: a supporting unit for freely attachably supporting a recording medium including a photosensitive material; a signal light-generating unit for projecting a coherent light beam modulated according to a predetermined data into a recording medium and generating a diffraction grating by providing a three-dimensional light interference pattern in the recording medium; a detector unit for detecting and photoelectrically converting a diffracted light from the diffraction grating; and a demodulating unit for demodulating a predetermined data from an output from the detector unit. The detector unit has an intermediate data-generating unit for generating an intermediate data, and the demodulating unit has a conversion table in which the intermediate data and the predetermined data are uniquely associated, and demodulates the predetermined data by performing a computation based on a correlation in the conversion table.

Hologram recording/reproducing system

A hologram recording and reproducing apparatus preforms to record data on a recording medium and reproduce data from the recording medium. The recording medium is made of a photorefractive crystal having a parallel plate shape. The apparatus includes: a support portion for detachably supporting and rotating the recording medium; a recording-reference-light-beam-supplying-portion for supplying a coherent recording reference light beam propagating along an optical axis to a major surface of the recording medium; a signal-light-beam-supplying-portion for supplying a coherent signal light beam which is modulated in accordance with image data, in an optical path into the recording medium such that the signal light beam intersects with the reference light beam to produce an optical interference pattern with the reference and signal light beams within the recording medium; a reproducing-reference-light-beam-supplying-portion for supplying into the recording medium a coherent reproducing reference light beam propagating in an opposite direction along the optical axis of the recording reference light beam to generate a phase conjugation wave from a refractive-index grating of the light interference pattern; a splitting portion for splitting the phase conjugation wave from the optical path of the signal light beam to image a dot pattern with the phase conjugation wave; a photo-detecting portion for detecting the dot pattern imaged with the phase conjugation wave to reproduce the image data.

Hologram recording and reproducing apparatus

A description is provided of an optical information recording and reproducing apparatus having a volume holographic memory. The apparatus is capable of recording an interference pattern in the volume holographic memory in high density and can be made small-sized. The apparatus includes a comprises support portion for detachably supporting the volume holographic memory, which is made of a photorefractive crystalline material; a reference beam supplying portion for making a coherent reference beam of a first wavelength incident on the volume holographic memory; a signal beam generating portion for making a coherent signal beam of the first wavelength, which is modulated in accordance with image data, incident on the volume holographic memory, intersecting therein the signal beam with the reference beam, and generating a three-dimensional light interference pattern of the signal beam and the reference beam; and detecting a portion for detecting diffracted light from a refractive index grid of the light interference pattern in the volume holographic memory, due to irradiation of the reference beam. The signal beam and the reference beam are arranged in a plane having a normal line perpendicular to the symmetrical axis of rotation of the volume holographic memory.

Optical information recording and reproducing apparatus having volume holographic memory

In a hologram recording method for forming a plurality of areas of a refractive index light interference pattern of a coherent signal light beam in accordance with information data within a recording medium having a shape of parallel flat plates, the signal light beam and the recording reference light beam cross each other within the recording medium, and a gate light beam having a second wavelength for revealing recording sensitivity of the recording medium is simultaneously irradiated to the recording medium so as to pass through a portion of the recording reference light beam and demarcate a volume smaller than that of this crossing portion.

Hologram recording medium, hologram recording method and hologram recording and reproducing apparatus

A description is provided of an optical information recording and reproducing apparatus. The apparatus comprises: a holographic memory made of a photorefractive crystalline material; a support portion for detachably supporting the memory; a reference beam supplying portion for supplying a coherent reference beam of a first wavelength incident on the memory; a signal beam generating portion for supplying a coherent signal beam of the first wavelength, which is modulated in accordance with image data, incident on the memory, intersecting therein the signal beam with the reference beam, and generating a three-dimensional interference pattern of the beams; a detecting portion for detecting a diffracted light from a refractive index grating of the interference pattern in the memory, due to irradiation of the reference beam; and a medium position adjusting portion for moving a position of the support portion in accordance with a signal corresponding to positioning images from the detection portion. The memory includes a nonvolatile refractive index grating corresponding to a three-dimensional interference pattern of a coherent reference beam and a coherent signal beam, the coherent signal beam being modulated in accordance with positioning images.

A volume holographic memory for recording three-dimensional distribution of interference fringes generated owing to interference between signal light and reference light is provided, wherein the volume holographic memory is formed into a cylindrical shape. Also an optical information recording/reproducing apparatus is provided which incorporates an interference-fringe generating unit for generating interference fringes formed owing to interference between signal light and reference light; a storage unit for storing three-dimensional distribution of the interference fringes generated by the interference-fringe generating unit; a detecting unit for detecting diffracted light obtainable from the storage unit by irradiating the storage unit with reference light; and a reproducing unit for reproducing signal light from diffracted light detected by the detecting unit, wherein the storage unit is constituted by a volume holographic memory having a cylindrical shape.

Volume holographic memory and optical information recording/reproducing apparatus

Disclosed are a holographic memory medium for use in a holographic memory system, which can prevent generation of stray light of a gating beam at the time of recording information, and a recording apparatus which uses this memory medium. This memory medium records an information signal carried by a signal beam as a coherent reference beam and the signal beam enter the memory medium with a gating beam being present. The memory medium has at least a first surface and a second surface parallel to each other and comprises an antireflection coat, formed on the first surface, for preventing reflection of the gating beam. The recording apparatus records an information signal using a holographic memory medium and comprises a light absorbing member of absorbing the gating beam coming through the memory medium.

Holographic memory medium and recording apparatus using the same

An optical information recording/reproducing system includes a support member for removably supporting a volume holographic memory formed of a photorefractive crystal, and has a shape of a rotary member having a rotational symmetry axis, with plane surfaces perpendicular to the rotational symmetry axis formed at respective opposite ends thereof. The system also includes a reference beam-irradiating member for irradiating the volume holographic memory with a coherent reference beam having a first wavelength. The system also includes a signal beam-irradiating member for irradiating the volume holographic memory with a coherent signal beam which has the first wavelength and is modulated according to image data, to cause the signal beam to intersect with the reference beam within the volume holographic memory and thereby generate a refractive index grating of a three-dimensional optical interference pattern between the signal beam and the reference beam. The system also includes a member for detecting a diffracted light generated by irradiation of the reference beam on the refractive index grating of the optical interference pattern. The support member holds the volume holographic memory in a position allowing the signal beam to pass through the plane surfaces of the volume holographic memory at the respective opposite ends thereof.

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Tsurugashima, Japan

Yoshihisa Itoh