Sony Corporation

Mikio Sugiki

Tomiji Tanaka

Mitsuru Toishi

Kenji Tanaka

Atsushi Fukumoto

Koji Ishioka

Kazuo Takahashi

Kenjiro Watanabe

Masaaki Hara

Hitoshi Okada

Naoto Kojima

Kazuyuki Hirooka

Shigeo Kobayashi

Yohsuke Naruse

Toshiyuki Nakagawa

Hiroshi Mori

Hiroo Takahashi

Masanobu Yamamoto

Kiyoshi Ohsato

Hideo Owa

Tetsuo Urabe

Shigeru Yamazaki

Kazutatsu Tokuyama

Shinichiro Kuwabara

Koji Takasaki

Hiroya Usui

Nobutomo Umeki

A hologram recording/reproducing device includes a recording/reproducing optical unit performing recording and reproducing operations on a hologram recording/reproducing medium. The optical unit includes a laser light source emitting laser light; a spatial-light modulator generating signal light and reference light from the laser light, the signal light and reference light having a common light path; a phase mask disposed near the modulator or in a conjugate plane of the modulator and transmitting at least the reference light; and an objective lens including a first lens portion and a second lens portion. The first lens portion is disposed at an inner peripheral portion of the objective lens and serves as a Fourier transformation lens focusing the signal light to a predetermined point. The second lens portion is disposed at an outer peripheral portion of the objective lens and has focuses continuously or discretely disposed in an optical-axis direction of the objective lens and at portions in the medium near the predetermined point.

Hologram recording/reproducing device and recording/reproducing optical apparatus

In a reproducing apparatus adapted to reproduce data recorded on a holographic recording medium, a reference light generator generates reference light for illuminating the holographic recording medium, and a coherent light generator generates coherent light having an intensity greater than the absolute value of a minimum amplitude of a reproduced image and having a phase equal to the phase of the reproduced image. An image signal acquisition unit senses the reproduced image produced by illuminating the holographic recording medium with the reference light and the coherent light, and acquires an image signal based on the reproduced image. A square root calculation unit calculates the square root of each of values constituting the image signal. A removal unit removes the component of the coherent light from the calculated square root, whereby the data recorded on the holographic recording medium is correctly reproduced.

Reproducing apparatus and reproducing method

A recording apparatus performing at least recording with respect to a hologram recording medium is disclosed. The recording medium includes: a light emitting means for emitting light to be radiated with respect to the hologram recording medium set at a prescribed position; a spatial light modulation means configured to be able to generate reference light and signal light to be radiated to the hologram recording medium by performing light intensity modulation to incident light in the unit of pixels; a phase modulation means for performing phase modulation to radiated light from the spatial light modulation means; and an optical system configured to guide light emitted from the light emitting means with respect to the hologram recording medium through the spatial modulation means and the phase modulation means.

Recording apparatus and phase modulation device

A holographic recording and reconstructing apparatus includes a light source having a variable oscillation wavelength; a temperature sensing unit operable to sense temperature; and a control unit operable to record information about a temperature sensed by the temperature sensing unit on a holographic recording medium during recording, to obtain the information about the temperature from the holographic recording medium and obtain a temperature sensed by the temperature sensing unit during reconstruction, to determine the amount of wavelength shift to counteract the effects of a change in the dimension of the holographic recording medium between recording and reconstruction based on the difference between the temperatures, and to shift the oscillation wavelength of the light source by the determined amount.

Holographic recording and reconstructing apparatus and method

In the hologram recording and hologram-record reproduction using a one-dimensional optical modulator, the one-dimensional optical modulator where a plurality of light-modulating pixels are arranged modulates a laser beam to record a digital-data signal on a hologram recording medium, and part of the light-modulating pixels record sync signals in two or more positions on the hologram recording medium with retaining a predetermined interval, thereby improving hindrance to reproduction or readout of information recorded on the hologram recording medium, a decrease in S/N, and so on due to deformation or the like of the hologram recording medium.

Hologram recording method, hologram recording reproduction method, hologram recording device, hologram recording/reproduction device and hologram reproduction device

A hologram recording/reproducing device includes a laser light source emitting laser light; a spatial light modulator generating signal light and reference light from the laser light emitted from the laser light source, the signal light and the reference light traveling in a common light path; a first relay lens system including a first shielding plate at a focal position thereof and transmitting the signal light and the reference light generated by the spatial light modulator, the first shielding plate having a pinhole whose size is 1 to 2 times a Nyquist size; a phase modulating element disposed at a conjugate plane of the signal light and the reference light transmitted through the first relay lens system; an objective lens converging the signal light and the reference light transmitted through the phase modulating element on a hologram recording medium; and a light receiving system disposed between the phase modulating element and objective lens and receiving light returning from the hologram recording medium.

Hologram recording/reproducing device and optical unit

A holographic recording/reproducing apparatus includes a splitter unit for splitting a laser beam into a first laser beam for generating a signal beam and a second laser beam which serves as a reference beam, a spatial light modulator for spatially modulating the first laser beam in accordance with information to be recorded, the modulated first laser beam serving as the signal beam, and a first lens system for focusing the signal beam and the reference beam onto a holographic recording medium. In a recording process, the signal beam and the reference beam are guided through one and the other half-regions separated along the optical axis of the first lens system. In a reproduction process, only the reference beam is guided through one of the half-regions and a signal reproduction beam from the holographic recording medium is guided through a second lens system in the other half-region.

Holographic recording/reproducing apparatus and reproducing apparatus for holographically recorded information

A hologram recording apparatus, a hologram recording method and a hologram recording medium reduce noise components generated by a phase modulation type spatial light modulator, thus permitting improved integrity of data to be achieved. A light beam whose diffraction state has been controlled by a diffraction control element is condensed on a hologram recording medium. With this arrangement, a predetermined diffracted light component is removed from a diffracted light beam emergent from the diffraction control element when recording information, which is based on the diffraction state controlled by the diffraction control element, in a hologram recording medium. Thus, noise components when information is recorded can be reduced.

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

In an apparatus and method for optically recording on an optical disk a television signal comprised of a color image signal and an audio signal; one horizontal period portion of an original luminance signal and one horizontal period portion of two original color difference signals from a standard television signal are time-base-compressed to generate a time-base-compressed video signal for one horizontal period, the audio signal is digitized and time-base-compressed, and then the time-base-compressed digital audio signal and the time-base-compressed video signal are time-division-multiplexed with each other and recorded on the optical disk.

Apparatus and method for recording a color television signal on an

Anamorphic prism

Recording/reproducing optical system utilizing semiconductor laser light

A liquid crystal display apparatus wherein laser beams which are modulated in accordance with modulating signals such as video signals are irradiated on a liquid crystal cell for writing the display image or picture on the cell. In the present invention, the laser beams emitted from two laser beam sources are combined at a polarization beam splitter with an angular offset between the respective optical axes equal to .DELTA..theta., and the picture components corresponding to two scanning lines are simultaneously written into the liquid crystal cell during one scanning period, for increasing the image writing speed.

Liquid crystal display apparatus

Signal detecting system for use in optical reading apparatus

A reflection-type optical recording medium which has a surface on which track guide grooves are formed and in which a layer of a recording material that has an increased energy reflection coefficient in a write portion. The track guide grooves are formed with a depth .phi..sub.0 so that improved efficiency results because of the selection of various parameters of the system.

Optical recording medium

In an optical disc player in which a reading light beam is caused to impinge on an optical disc having a record track formed with an alignment of geometric variations such as a plurality of pits provided in response to information to be modulated in intensity by the record track and a photodetector is provided for detecting the reading light beam coming from the optical disc to generate an output varying in response to the variations in intensity of the detected reading light beam; there are provided a first circuit for producing a reproduced information signal having level variations representing the geometric variations and a tracking error signal which may have level variations depending on the size of each segment of the geometric variations on the strength of the output of the photodetector, a second circuit for detecting the duration of a portion corresponding to each segment of the geometric variations of the reproduced information signal or output of the photodetector and extracting selectively the level of the tracking error signal whenever the detected duration is measured within a predetermined time range so as to produce a modified tracking error signal having the extracted level, and a control circuit for performing tracking control in relation to the reading light beam in response to the modified tracking error signal.

Growing community of inventors

Kanagawa, Japan

Mikio Sugiki