Abstract: A magneto-optical disk according to the present invention has a transmission directory and a reception directory. An image to be transmitted is stored under the transmission directory as a single file, while a received image is stored under the reception directory as a single file. The operator designates a desired file stored under each of the directories for printing or transmission.

Abstract: An information processing method and system in which coded or incomplete information is transmitted through a space or through a predetermined transmission line and is received by a user. A program or data needed to demodulate the information is read out from a recording medium, and the received information is demodulated using the read out program or data.

Abstract: Optical pickup apparatus using split beams impinging on different photo-detector areas includes optical structure for projecting a light beam polarized in a predetermined direction toward a recording medium where information is recorded. Optical separating structure is provided for dividing a light beam reflected by the recording medium, with modulation of its polarization state in accordance with the recorded information, into first and second light beams which are polarized in directions perpendicular to each other. First and second light detectors respectively detect the first and second light beams. Preferably, a single lens is located between the separation structure and the first and second light detectors for converging the first and second light beams. Also preferably, the first and second light detectors are formed on the same substrate and are each divided into a plurality of light receiving areas.

Abstract: An optical pickup apparatus having a photo-detection unit having a plurality of detectors, a unit for converting a light beam emitted from a recording medium on which information is magnetically recorded and intensity-modulated, and splitting the light beam into two beams guide them respectively onto different areas of the photo-detection unit, and a device for processing outputs from each area of the photo-detection unit to provide an information signal.

Abstract: An optical pickup device for producing information magnetically recorded on a recording medium includes a light source for generating a light beam polarized in a predetermined direction. An object lens is provided for focusing the light beam generated from the light source onto the recording medium. A beam splitter is arranged in an optical path extending from the light source to the recording medium, the beam splitter having a reflection plane for reflecting the light beam from the light source toward the recording medium. The beam splitter simultaneously causes the reflecting light from the recording medium to pass through the reflection plane to separate the reflected light beam from the light beam irradiated toward the recording medium. The polarization state of the reflecting light beam is modulated in accordance with the recorded information.

Abstract: In an information recording medium, there are provided with plural information track groups each provided with plural information tracks, and identification areas respectively formed in the plural information track groups and having codes respectively indicating the information track groups. An information reproducing process, for reproducing the information from the information reproducing medium, comprises the steps of detecting a code of the identification area indicating a desired information track group, and reproducing the information stored in the information track group, in response to the result of the detecting step.

Abstract: In an optical recording medium a substrate is provided having at least a recording surface and a recording layer on an area of the recording surface having a length in a longitudinal direction. A set of linear continuous tracking tracks is formed on the recording surface. The tracking tracks have a length which is greater in the longitudinal direction than the length of the recording layer with a constant distance between adjacent tracks, which distance is equal to or larger than twice the width of each track. Recording areas are arranged and constructed so as to record information irradiated with a light beam. Each of those areas is positioned between neighboring tracking tracks.

Abstract: An optical head device comprises a light source, a light splitter for reflecting a light emitted from the light source by a first plane thereof to direct the light to an information carrier and transmitting the light from the information carrier through the first plane, a photo-detector for detecting the light from the information carrier, and a diffraction grating structure arranged on a second plane of the light splitter for diffracting the light transmitted through the first plane and directing it to the photo-detector.

Abstract: An information recording and/or reproducing apparatus in which a beam emitted from a light source is applied to an optical recording medium to thereby record and/or reproduce information thereon has a light projecting device for projecting a medium-detecting-light flux onto the surface of the optical recording medium, a discriminating device for detecting the level of the reflected light or the transmitted light of the medium-detecting-light flux from the optical recording medium and discriminating between optical recording mediums different in characteristic by the detected level, and an intensity changing device for changing the intensity of the beam on the surface of the optical recording medium in accordance with the determination of the discriminating device.

Abstract: A method and apparatus for accessing a track in a recording medium during a stopped state of recording or reproduction. The method includes accessing a recording and/or reproducing device to a desired track of a plurality of tracks on the information recording medium. The recording and/or reproducing device and the recording medium are not relatively moved in a longitudinal direction of the tracks, while the recording and/or reproducing device is moved relative to the recording medium in a direction which crosses the tracks.

Abstract: This specification discloses a card-like optical information recording medium comprising a card-like base body, and concentric circular or spiral information tracks provided on the base body and capable of optically recording and/or reproducing information thereon. The specification also discloses an apparatus for recording and/or reproducing information on such card-like optical information recording medium which comprises a turn table rotatable with the card-like medium being placed thereon, a clamp mechanism for positioning and fixing the card-like medium on the turn table, and an optical head for applying a light beam to the card-like medium while moving radially of the rotation, thereby effecting recording and/or reproduction of information concentrically or spirally.

Abstract: An optical information recording and reproducing apparatus comprises: a laser light source having a Gaussian intensity distribution of an emitted laser beam; an optical system for focusing the laser beam emitted from said laser light source, having a number of aperture NA represented by ##EQU1## wherein .lambda. is a wavelength of the laser beam emitted by said laser light source, and .omega..sub.0 is a diameter of a laser beam spot focused by said optical system.

Abstract: An optical head device comprises a light source, condensing optics for condensing a light beam emitted from the light source on an optical recording medium, a photodetector for detecting the light of the light beam reflected from the recording medium, and a beam splitter having a diffraction grating arranged in the optical path of the light beam entering the recording medium from the light source along a plane substantially perpendicular to the optical axis of the incident light beam to cause the light reflected light from the recording medium to be diffracted by the diffraction grating and directed to the photodetector.

Abstract: In an optical head for effecting the recording of information onto a recording medium or the reproduction of information from the recording medium, a light beam supplied from a light source unit is directed to the recording medium by a first optical system, the light beam from the recording medium is divided into two light beams by a light divider in a second optical system and the two light beams are directed to photodetectors by the second optical system, and even if the light beam entering the light divider is displaced by tracking, the quantities of light of the two divided light beams are not varied, whereby the influence of the tracking operation on auto focusing is eliminated.

Abstract: An information recording-reproducing method of recording information from a plurality of information sources on a recording medium and reproducing the information is characterized by dividing the information from each information source into a plurality, recording the divided information from the first information source along the signal tracks of the recording medium at predetermined intervals, recording the divided information from the other information sources between recording areas in which the divided information from the first information source is recorded, and reproducing the information along the signal tracks.

Abstract: Disclosed is a photo-magnetic reproducing apparatus in which an incident light beam polarized in a predetermined direction enters a recording medium on which information is magnetically recorded. The light beam from the recording medium is split into two light beams, and a signal containing the information therein is detected from one of the split light beams, while a signal not containing the information therein is detected from the other of the split light beams. The detected two signals are differentiated to thereby obtain an information reproducing signal.

Abstract: This invention provides a device for measuring light incident on an optical system. This device includes an optical system defining an optical path, a beam splitter and a photo detector. The beam splitter has a relief type diffraction lattice having a plurality of semireflecting surfaces periodically arranged and included in a transparent body. The diffraction lattice is arranged to split a portion of the incident light by its effect of reflection/diffraction and its beam splitting efficiency having a predetermined distribution within the lattice area. The diffracted light from the diffraction lattice is directed to the photo detector.

Abstract: In a magnetooptic reproducing device wherein a light beam polarized in a predetermined direction is incident on a magnetic recording medium and signals recorded on the recording medium are optically read by the utilization of the magnetooptic effect, a polarization component of the signal light from the recording medium in a direction perpendicular to a polarization component in the predetermined direction is relatively increased as compared with the latter component, thereby enhancing the utilization efficiency of the signal light in detection and enabling detection of great S/N ratio or observation of a recorded pattern of high visibility. Also, signal recording as well as reproducing can be accomplished by one common optical system.

Abstract: A device for measuring light incident on an optical system comprises an optical system defining an optical path, a plurality of diffraction lattices arranged in the optical path, each of the diffraction lattices comprising a plurality of periodically arranged semireflecting oblique surfaces, and photodetector means for detecting each of the diffracted lights from the diffraction lattices distinctively. The diffraction lattices are each of different predetermined areas; however, when even light is input, each lattice diffracts the same total quantity of light to its respective detector.

Abstract: A system for measuring incident light includes: an optical system defining an optical path; a photodetector; and a plurality of beam splitters, with each beamsplitter having a different, predetermined area and adapted to be disposed in the optical path with, at any one time, only one beam splitter in the optical path; and means for measuring the light received by the photodetector.