Ricoh Company, Ltd.

Junichi Kitabayashi

Shigeru Ohuchida

Hideo Maeda

Shigeru Oohchida

Toshio Kanoh

Kazuhiro Fujita

Tatsuya Takahashi

Makoto Hirakawa

Hiroyoshi Funato

Toshiharu Murai

Takehiro Nishimori

Toshiyuki Inokuchi

Takeshi Miki

Tetsuya Ogata

Yukio Ogura

Toshio Inada

Tsuyoshi Suzudo

Keishin Tsuchiya

Kaoru Itoh

Suguru Douwaki

A light irradiation device for emitting light of two or more components by laser light, which a laser light source emits, to an outside, includes a diffusion optical path change member configured to convert a first color component of the laser light into diffusion light and change an optical path of the first color component; a phosphor configured to generate fluorescence of a second color component different from the first color component based on the laser light, and change an optical path of the second color component; and an optical path switch member configured to switch between a first optical path for emitting the first color component to the outside and a second optical path for emitting the second color component to the outside. Light going straight at a light diffusion position of the diffusion optical path change member is not emitted to the outside.

Light irradiation device, and image display equipped with the same, for emitting light of two or more components by laser light

A light source unit comprises a plurality of light sources emitting a plurality of light beams. A plurality of volume hologram elements are provided for the plurality of light sources respectively, each volume hologram element having a plane of incidence of an incoming light beam and a plane of outgoing radiation of a diffracted light beam which are perpendicular to each other, the plurality of volume hologram elements having mutually different Bragg conditions in which an optical intensity of a diffracted light beam is set to a maximum.

Light source unit, optical detector unit, optical pickup device, and optical disk device

A tilt sensor for detecting information related to a tilt of an object to a reference plane is disclosed. The tilt sensor includes a diffraction element disposed that diffracts an incident light at diffraction efficiency depending on the incident angle, and a photo detector that detects a diffraction light diffracted by said diffraction element and outputs an photoelectric signal. Since the diffraction efficiency of the diffraction element changes as the incident angle changes, the intensity of the diffraction light from the diffraction element changes. As a result, the photoelectric signal output from the photo detector contains the information related to the tilt of the object.

Tilt sensor using diffraction grating

A polarization diffraction grating includes two media having different orientation states arranged alternately and cyclically, wherein each boundary between the media forms an oblique rectangular shape.

Diffraction grating, light source unit applying the same therein, and optical head device employing the same

An objective lens causes light emitted from the light source to converged onto an optical recording medium. A beam splitter separates light, reflected from the optical recording medium, from the bundle of rays emitted from the light source. A detective lens causes the light separated by means of the beam splitter to be converged. A detective photosensitive element is disposed at a position at which the light converged by means of the detective lens approximately converges. The detective lens has a first and second surfaces. The first surface faces the beam splitter and is formed to be convex so as to cause the bundle of rays to converge. The second surface comprises two surfaces which are combined with one another so that the line of intersection, formed where the two surfaces meet, does not intersect the axis associated with the convexity of the first surface.

Optical pick-up system with improved light-convergence construction

A focus error signal detection device comprising an optical system for guiding a reflection beam reflected from an optical information recording medium to a photo-detection system side. A beam dividing system is arranged for dividing the reflection beam to two beams. Two photo-detecting units are arranged for detecting the two divided beams, respectively, each unit having light receiving surfaces arranged on a same plane. A beam position adjusting system is arranged for adjusting optical axes of the two divided beams with respect to predetermined positions of the photo-detecting units by simultaneously moving the two detecting units with respect to the beam dividing system.

Focus error signal detection device with separating prism

An optomagnetic information recording and reproducing apparatus includes an optomagnetic optical pick-up for recording or reproducing information on or from an optomagnetic information recording disc. An optomagnetic optical pick-up includes a first diffraction grating for receiving light reflected from the disc and separating the light into a first transmitting light which transmits through the first diffraction grating beam and a first diffracted light beam which is diffracted by the first diffraction grating. A second diffraction grating is disposed to receive the first transmitging and diffracted light beams and discharges a second transmitting light beam and a second diffracted light beam. A tracking error detector is provided to receive the second transmitting light beam and a focusing error detector is disposed to receive the second diffracted light beam. An optomagnetic signal is obtained as a difference between outputs from the tracking and focusing error detectors.

Optical pick-up for use with an opto-magnetic signal

A parallel image processing apparatus includes (1) a light diffusing layer, (2) a photoelectric conversion layer which receives diffused light from the diffusion layer, and (3) an edge detection layer which receives signals from conversion elements in the conversion layer, and generates edge information which defines the edge of object(s) imaged on the light diffusing layer. The conversion layer includes pairs of conversion elements, the pairs having a center element and a peripheral element surrounding it. Signals from one or more center elements are summed, the sum being differentially amplified with a sum of signals from one or more peripheral elements to arrive at an edge signal. Edge signals may be used to differentiate among characters, pictures or photographs, and a blank images.

Parallel image processing apparatus using edge detection layer

An optomagnetic information recording and reproducing apparatus includes an optomagnetic optical pick-up for recording or reproducing information on or from an optomagnetic information recording disc. An optomagnetic optical pick-up includes a first diffraction grating for receiving light reflected from the disc and separating the light into a first transmitting light which transmits through the first diffraction grating beam and a first diffracted light beam which is diffracted by the first diffraction grating. A second diffraction grating is disposed to receive the first transmitting and diffracted light beams and discharges a second transmitting light beam and a second diffracted light beam. A tracking error detector is provided to receive the second transmitting light beam and a focusing error detector is disposed to receive the second diffracted light beam. An optomagnetic signal is obtained as a difference between outputs from the tracking and focusing error detectors.

Optomagnetic recording/reproducing apparatus

An optical information recording/reproducing apparatus comprises a semi-reflecting means which receives a emitted laser light emitted from a light source, which reflect partially the received laser light toward an optical information recording medium in order to record an information, and which transmits a reflected laser light reflected by the optical information recording medium, a separating means which has the semi-reflecting means on one surface thereof, which diffracts a part of the transmitted laser light, transmits the other part of the transmitted laser light, and then subsequently diffracts said diffracted light again to produce twice diffracted light and transmits said transmitted light again to produce twice transmitted light, and a detecting means which detects the diffracted laser light and the transmitted laser light to thereby generate an information reproduction signal, a track error signal and a focus error signal.

Optical information recording/reproducing apparatus

An optical information reading and writing device comprising a laser source which emits a laser beam for irradiating an optical recording disk to record an information therein and an optical signal detection system which receives a reflection beam reflected from the disk surface and controls position of the disk. The optical signal detection system comprises a condenser lens for converging the reflection beam and a dual grating element which has linear diffraction gratings formed on its both side surfaces. The incident side grating divides the reflection beam to two beams, one being a beam which is diffracted by the grating and the other being a beam which passes substantially straight through the grating without being diffracted thereby. The optical signal detection system further comprises a pair of three-segment light receiving detector elements for detecting the divided two beams. The two detector elements are disposed on a same plane.

Optical information reading and writing device with diffraction means

Two light beams capable of interference with each other are applied to an area sensor while they are inclined to each other. The area sensor reads a pattern of interference fringes formed by the two light beams. The read interference fringe pattern is subjected to a Fourier transform, and then an inclination-related component is removed therefrom. Thereafter, an inverse Fourier transform is effected. The shape of the wavefront of light to be measured is determined on the basis of a phase difference between the two light beams which is known from the result of the inverse Fourier transform.

Method of and apparatus for measuring the shape of a wavefront

A device for optically measuring an aspheric surface includes a fringe-scanning shearing interferometer for applying a wavefront of illuminating light to the aspheric surface and optically measuring the aspheric surface based on light reflected by the aspheric surface along a measurement optical path. A plurality of ring filters having respective different light-transmitting areas are successively positionable, one at a time, in the illuminating light and outside of the measurement optical path for applying divided portions of the wavefront of illuminating light successively to the aspheric surface. The radius of curvature of the wavefront of illuminating light applied to the aspheric surface is measured.

Device for optically measuring aspheric surface

A method of measuring the origin and amount of a shear between a basic light beam and a reference light beam in a shearing interferometric system. To detect the shear origin, shutters are disposed respectively in the optical paths of the basic and reference light beams. The basic and reference light beams are guided through a condenser lens toward a four-segment light detector. First, the optical path of the reference light beam is closed to allow only the basic light beam to fall on the four-segment light detector. By adjusting the position of the light detector, the position of the basic light beam is identified. Then, the optical path of the basic light beam is closed to allow only the reference light beam to reach the light detector. While output signals from the light detector are being monitored, a shearing member is displaced to shift the reference light beam to detect the shear origin in which the reference and basic light beams are overlapped. To measure the shear amount, light of a plane wave is used as the basic light beam, and the basic and reference light beams caused by an imaging lens to fall on an area sensor are of plane wavefronts. An interference fringe pattern on the area sensor is measured by a fringe scanning process to determine an angle at which the wavefronts of the basic and reference light beams are inclined to each other. The shear amount is computed from the determined angle and the focal length of the imaging lens.

Method of detecting origin of shear and measuring amount of shear in

A focusing method for interferometer wherein a light flux passing through a converter lens for converting the shape of wave fronts is caused to be incident on a tested surface and a testing light beam reflected by the tested surface is caused to be incident on a light receiving element capable of measuring the distribution of intensity of the light at least one-dimensionally. The tested surface is moved in the direction of its center axis until it reaches a position in which the vertex of the tested surface coincides with the focus of the converter lens and the output of the light receiving element shows a peak value, and the tested surface is further moved, from the position referred to hereinabove which serves as a reference position, in the direction of its center axis.

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Kawasaki, Japan

Junichi Kitabayashi