Abstract: A light detection apparatus includes at least one re-imaging lens that re-images a light beam reflected from an optical storage medium, to form an image of a light spot formed by the light beam on the storage medium. At least one detector detects a selected portion of the image The selected portion of the image contains only such information as is encoded on a region of the optical data storage medium that is illuminated by a corresponding portion of the light spot.

Abstract: In a method for recording information in an optical data memory by surface exturing, a substrate surface is first pre-treated or sensitized by selective irradiation at relatively low fluence. For selectivity of irradiation, a mask, a holographic imaging process, or direct writing may be used. In a second step, the sensitized regions are ablated from the surface by means of spatially non-selective irradiation at a different wavelength and at relatively high fluence.

Abstract: A system and method for recording on optical storage media utilize a beam projection assembly including a collimating lens and an objective lens. By providing an incident light beam having a substantially constant energy distribution to the objective lens, the radius of the spot projected on the optical media having an intensity greater than a threshold intensity may be increased. The radius may be further decreased by modifying the optics of the objective lens, typically by providing a center stop plate on the lens or by providing a one-half wavelength plate on the lens.

Abstract: An optical disc apparatus having a semiconductor laser (7), and a beam splitter (11) which guides a laser light emitted from the semiconductor laser to an optical disc (2) and also guides a laser light reflected from the optical disc (2) to a detection system for detecting information carried by the reflected light. The optical disc apparatus comprises an optical axis direction change device (10) provided between the semiconductor laser (7) and the beam splitter (11) for changing the direction of the laser light emitted from the semiconductor laser, wherein, the angle (.theta.) between the optical axis of the laser light emitted from the semiconductor laser and the laser light reflected from the optical disc is less than 90.degree..

Abstract: A thruhole 23 is provided with a movable member so that a light beam irradiated from an LED passes through the thruhole and is received by a photo detector for positional detection whereby the position of an objective lens relative to the light receiving groove of an information recording medium is detected. At the same time, a light beam passing through the thruhole 46 and reflected by the information recording medium is received by a photo detector for inclination detection whereby the inclination angle of the objective lens against the information recording medium is detected.

Abstract: A high-density recording optical head for increasing recording density in an optical head for recording and reproducing information optically. The disclosed optical head is provided with an iris for transmitting or passing the central portion of the reflected light when the light reflected from a medium is transmitted by an ordinary objective lens. Another iris is also provided for transmitting or reflecting the periphery of the reflected light and, in this case, an improved objective lens structure including two inner and outer elements is provided. Therefore, in the disclosed optical head, only light reflected from the actual recording region is detected as a reproduction signal. According to the disclosed optical head, high-density recording in identical media becomes possible.

Abstract: An apparatus for storing and reading a magneto-optical disk has a slit shaped aperture located in an air-bearing slider which flies above the disk. Domains of the disk are selected for storing or reading by a light beam. The domains are reduced in size without losing inter-domain resolution by illuminating the disk with the portion of a focused laser beam incident on the disk through the slit, the slit width being less than the full beam width. The slider preferably terminates a wedge-shaped cavity suspended above the medium a distance substantially less than the wavelength of the illuminating light; the thickness of the edges of the slit being substantially less than the wavelength of the illuminating light.

Abstract: An optical pick-up for an optical disk has a semiconductor laser having an optical axis for generating a laser beam. An objective lens focuses the laser beam onto an optical disk disposed in the path of the optical axis of the semiconductor laser. A wavelength between the semiconductor laser and the objective lens has a plurality of input grating couplers for coupling the laser beam reflected from the optical disk into the waveguide for propagating beams in a plurality of directions. A plurality of output grating couplers radiate the propagated beams from the waveguide. A plurality of photodetectors detect the radiated beams from the output grating couplers.

Abstract: An apparatus for reading information out of an optical record medium including a semiconductor laser diode for emitting a laser beam, a collimator lens, a beam splitter, an objective lens, converging lens and a photodetector. The laser beam emitted from the laser diode is made incident upon the optical record medium via the collimator lens, beam splitter and objective lens, and a light flux reflected by the optical record medium is made incident upon the photodetector via the objective lens, beam splitter and converging lens. The laser diode and collimator lens are arranged such that the laser beam is projected upon the optical record medium in a de-focused condition, while the objective lens is in-focused on the optical record medium.

Abstract: Recording and/or reading of information on an optical record carrier is effected by scanning such record carrier with a radiation beam which is focussed by an objective lens into a scanning spot of a size which is diffraction-limited by the aperture of the objective lens. The effective size of the scanning spot is considerably reduced by including a layer of non-linear optical material in the record carrier, such material having an optical characteristic which changes with changes in intensity of the radiation incident thereon. The read/write resolution of information on the record carrier is thereby substantially increased.

Abstract: An optical card recording/reproducing apparatus for recording/reproducing information onto/from an optical card by relatively moving the optical card to an optical head is provided. The optical head has an optical system for producing focusing and tracking control signals. The optical system includes a light emitting diode having a narrow slit-like light emitting surface as a light source. The optical system has photo sensitive elements for focusing control, a photo sensitive element for tracking control, and a recorded information reproducing photo sensitive element which are used to detect the reflected lights from the optical card of a slit light which is emitted from the light emitting diode. By forming a slit-like light spot onto the optical card, the focusing and tracking controls can be accurately easily executed and the deterioration in pits and track guides is prevented.

Abstract: A light scanning device comprising a source of a parallel light beam. The parallel light beam is passed through a first liquid crystal shutter and a first lens to converge at a focal point thereof. A rectangular light reflecting box with inside reflecting surfaces is arranged next to the first lens, so that a portion of the light beam passing through the first lens is able to directly pass through the light reflecting box and another portion of the light beam is reflected at the reflecting surfaces and then able to pass through light reflecting box, whereby multiple light paths are obtained. The passage of the multiple light paths is controlled by a second liquid crystal shutter located on the end of the rectangular light reflecting box, the second liquid crystal shutter having a plurality of selectively controllable light permeable regions.

Abstract: In an optical head apparatus, a minute light beam spot is formed on a recording medium by a focusing lens. The focusing lens focuses light radiated from a light source to provide the minute light beam spot. Between the light source and the focusing lens, a light intensity or phase distribution converter is provided, so that the minute light beam spot will be a super resolved light beam spot.

Abstract: Coherent light passing through slits produces an optical interference pattern having a fringe spacing related to the spacing of the servo tracks on a magnetic disk. The convolution of the interference pattern with the servo tracks generates a quadrature servo error signal.

Abstract: A micro-objective lens is carried on an air bearing slider with an optical passage through which the lens focuses an energy beam onto a spot on an optical data storage medium. The slider accomplishes automatic focusing. An RF coil is affixed to the slider facing the storage medium and surrounding the beam axis. The proximity of the coil lowers power switching requirements.

Abstract: A data playback apparatus for reproduction of data from an optical recording medium which has a data layer disposed on a substrate thereof having a specific thickness is provided with an optical length corrector interposed between the recording medium and an objective lens for converging a light beam. The optical length corrector is selected so that the sum of the optical length of the substrate of the recording medium and the optical length of the optical length corrector equals a predetermined length for the objective lens. Accordingly, the light passing the objective lens can converge on the data layer developing a light spot close to the limit of refraction, regardless of the thickness of the substrate of the recording medium.

Abstract: An optical system for reading and tracking multiple tracks of optically recorded data consists of a combination of spherical and cylindrical lenses shaping the emission of a laser diode into a narrow line on the surface of the recorded material. This line is subsequently imaged on a detector array containing multiple detectors for each data track being read. Digital signal processing identifies the tracks and follows them by selecting the proper detectors in the detector array. Track-to-track interference is minimized by selecting the numerical aperture of the final lens to have the nulls of the Airy pattern at double the track spacing.

Abstract: To prevent a drop in signal level at high spatial frequencies, an optical information reproducing apparatus retrieves the primary output of light reflected from the surface of a recording medium. In the different embodiments of the invention, either a shield plate with a pinhole in the path of the light is provided, or a photodetector having a plurality of light-receiving elements is provided, a selection circuit being connected to the elements and selecting the highest output thereof.

Abstract: An optical assembly incorporating a wedge-shaped optically transparent prism, a 45 degree right isosceles triangular prism which has two thin film coated surfaces, a rhomboidal prism attached to the triangular prism, a second, smaller 45 degree right isosceles triangular prism attached to one end face of the rhomboidal prism and two planoconvex lenses attached to the combination of the rhomboidal and second triangular prisms is mounted within a housing. All of the optical components are cemented to the adjacent component utilizing a transparent optical cement to form an integral unit.

Abstract: An optical disk apparatus comprises an optical pickup having an optical pickup body carrying a laser and a photodetector responsive to light emitted from the laser and reflected by the optical disk for producing tracking error signals mounted on the optical pickup body for reciprocal movement in a tracking direction responsive to operation of an actuator, and supports an objective for focusing the beam on the disk. A position sensor produces position signals in response to displacement of the movable portion in the tracking direction. Finally a servo tracking circuit outputs driving signals to the actuator on the basis of tracking error signals produced either in response to tracking error signals produced from outputs of the photodetector and position signals produced from output signals of the position sensor, in response only to the latter.

Abstract: Apparatus is described for pre-forming a relief structure of optically detectable servo-track portions and sector addresses on the recording layer of a record-carrier body, the maximum transverse width of the servo-track portions and sector addresses being the same and exceeding approximately 1/2 the track period P.sub.r but being less than approximately 3/4 P.sub.r. This enables the servo-track portions to be tracked in an optimum manner by a radiation beam and the sector-addresses and the information recorded by the user produce a read-out signal of high amplitude.

Abstract: An optical head and an optical information processor using the optical head include a light source, focusing device for focusing a light beam which is emitted from the light source, on an information medium, beam separator for isolating at least part of a light beam which is reflected from the information medium, from the light beam emitted from the light source, a beam splitter including a first polarized-light separating film which is illuminated with about a half of a light beam isolated by the beam separator, and a light detecting device having a first photodetector which receives a first light beam reflected from the first polarized-light separating film, and a second photodetector which receives a second light beam passing through the first polarized-light separating film, in a state that at least one of the first and second photodetectors is separated into a pair of light detecting elements, to make it possible to detect a magneto-optical signal and a focal error signal by the same optical system.

Abstract: The movable range of an objective of an optical pickup device used in optical disc reproducing apparatus is increased and the size of the device is reduced by moving the objective solely or in combination with a collimating lens system in that range. The objective and collimating lens systems are integrated into a lens holder and located in the path of a diverging beam of a semiconductor laser.

Abstract: A disc variation detecting apparatus comprises a light-sensitive element which faces the disc and is positioned together with a light-emitting element in a tangential direction of tracks on the disc. In this configuration, the following relationship is satisfied; d/L.ltoreq..beta./.alpha., where d is a width of a spot of the light beam in its displacement direction formed on the light-sensitive element, L is a length of the light-sensitive element in the displacement direction, .alpha. is an angular variation of the disc corrsponding to the length L, and .beta. is an allowable error angle range upon attitude control of a pickup.

Abstract: In an optical head, recording, reproducing and guide laser beams are emitted from semiconductor lasers, and the laser beams are optically mixed by a mixed. The mixed laser beams are converged onto a tracking guide of a recording surface by an objective lens and are reflected from the recording surface. The reflected laser beams are separated into the recording, reproducing and guide laser beams by the beam separator. The recording and guide laser beams are shielded in the beam separator, and only the reproducing laser beam is directed to photodetecting regions of information, tracking error and defocus detectors.

Abstract: The present invention is, in an optical head tracking error detecting apparatus in which a laser beam from a semiconductor laser element (1) is introduced into a diffraction grating (3), a 0-order beam and .+-.1st-order beams emitted from the diffraction grating (3) are introduced through a beam splitter (4) to an objective lens (5), a 0-order beam and .+-.1st-order beams of converged beams which are introduced into an optical recording medium (6) and reflected on the optical recording medium (6) are passed through the objective lens (5), reflected on the reflection surface of the beam splitter (4), and then introduced into a photodetector (7), a pair of photo-detection outputs corresponding to said .+-.

Abstract: The optical head in the recording-reading device of a data carrier comprises a semiconductor laser source. A lens makes it possible to focus the beam from this source on to the data carrier via a reflecting or deviating mirror. According to the invention the rotation axis of this mirror is in the plane of the entrance pupil and of the focus of the focusing lens.

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: A system and a method for applying a sound track to cinematic film by means of a modulated laser beam.

Abstract: An optical information processing apparatus is provided with a unit for recording and reproducing information by projecting a main beam onto an information track on a recording medium, a unit for projecting at least two or more than two subsidiary light beams onto the information track to form light spots at different position in the transversal direction of the information track by the respective light beams and a unit for detecting the subsidiary beams reflected by the recording medium to derive a tracking signal for guiding the main beams correctly on the information track, and those light spots are larger in size in the longitudinal direction of the information track than in the transversal direction thereof.

Abstract: An optical information reading apparatus wherein the intensity distribution of a light beam projected onto a video disk through an objective optical system is so made that the intensity in the direction along an information track is larger than the intensity in the direction intersecting at right angles with the information track in order to improve S/N and to eliminate cross-talks.

Abstract: A system for detecting and measuring fast scan jitter having first and second photosensors combined in a unitary detector positionable in the path of a scanning beam; means for generating a packet of test pixels for modulating the scanning beam for jitter through a succession of scan lines; said first and second photosensors outputting signal pulses representing the intensity of said scanning beam following modulation by said test pixels; a differential integrator for integrating the signal pulse outputs of said first and second photosensors with one another to provide a test signal for each line scanned; a filter for smoothing said test signal, an amplifier for amplifying said test signal, a peak to peak detector for comparing the test signal of one scan line with the test signal from the succeeding scan lines to provide a jitter signal where said test signals are different; and a meter for converting said jitter signal to a visual readout.

Abstract: The optical head in the recording - reading device of a data carrier comprises a semiconductor laser source. A lens makes it possible to focus the beam from this source on to the data carrier via a reflecting or deviating mirror. According to the invention the rotation axis of this mirror is in the plane of the entrance pupil and of the focus of the focusing lens.

Abstract: The camera or data recording apparatus (30) consists of an optical system for creating a data record on a photosensitive medium and includes a laser (36) for generating a light beam and mirrors (62, 72, 74 and 82) for transmitting the light beam to a final light beam path (56e) which is rotated about an axis (63) parallel spaced from the final light beam path (56e). Further the camera (30) includes an assembly (38) for shaping and focusing the light beam to have a bar shape cross section which is directed to the rotating final light beam path and imaged onto a photosensitive medium (86). A modulator (58, 60) modulates the light beam from the laser (36) intermittently to image or record light beam bar shape cross sections defining data in an arcuate path (14) on the photosensitive medium (86), a computer (32) controls the modulator (58, 60) and a carriage (88) is provided for moving the photosensitive medium (86) toward and away from the axis (63) about which the final light beam (56e) rotates.

Abstract: The locally averaged or approximate D.C. value of a variable area optical sound track on a film is first determined, and this information is then used to control the width of a scanning slit at a playback station. The scanning slit width is reduced for small signals and increased for large signals, thereby reducing the amount of non-information bearing area on the film which is included in the scanned area. This in turn reduces the amount of noise from dirt and debris in the non-information bearing area, and by reducing the total amount of light transmitted through the film also lowers the level of quantum noise from the photodetector employed at the playback station.

Abstract: In an optical reproducing apparatus a divergent beam from a semiconductor laser light source is collimated to form a parallel light beam that is converged by an objective lens and focussed on an optical record medium. The light beam is reflected by the optical record medium and introduced into a signal photodetector so as to provide a reproduced signal. A phase type diffraction grating between the semiconductor laser light source and a beam splitter separates the laser beam from the semiconductor laser light source into zero, plus first and minus first order diffracted beams. A pair of tracking photodetectors receive reflected beams of the plus first and minus first order diffracted beams reflected by the optical record medium and then by the beam splitter.

Abstract: A case provided with an information carrier consisting of a tape, one side of which has a structure carrying optically readable information as well as an apparatus for writing, reading or erasing such information. In the dustproof case containing a tape having on one side a structure carrying optically readable information, the tape is accomodated on two reels. The case is provided with one window through which a part of the tape between the reels is visible and with pressing means for urging that visible part of the tape against the window. This pressing means may be a wheel and the window may have the shape of a cylindrical lens.

Abstract: A focusing arrangement for an optical disk system that inhibits focus servo loop operation when the optical head objective lens is outside of a focus range distance with respect to the disk. In the optical head a laser beam converged by the objective lens is projected onto the light-reflecting layer of an optical disk. The laser beam reflected from the light-reflecting layer of the disk is projected to the light-receiving surface of a photodetector through the objective lens, a light shielding plate, a projection lens and a cylindrical lens. The laser beam is then projected to the light-receiving surface of the photodetector, thus forming a pattern thereon. As the objective lens moves along its optical axis, the laser beam is deviated and the pattern moves in a specific direction. The photodetector comprises first and second photosensitive regions.

Abstract: The invention provides an optical head having an objective lens whose optical axis is perpendicular to a light-reflecting layer of an optical disk. Parallel laser beams are incident on the objective lens and are focused on the light-reflecting layer. The laser beams reflected by the light-reflecting layer are transferred to a projection lens through the objective lens, and are projected on a light-receiving surface of a photodetector. An image of a beam waist of the laser beams converged by the objective lens is formed on the light-receiving surface through the objective and projection lenses. A light-shielding plate with an aperture is arranged between the projection lens and the objective lens. Only part of the laser beams which passes through an area spaced apart from a common axis of the objective and projection lenses is transmitted through its aperture. A projected pattern is moved on the light-receiving surface, depending upon a distance between the objective lens and the light-reflecting layer.

Abstract: A playback optical system for video discs comprising a light shield plate arranged in the vicinity of the pupil of the read-out lens, said optical system facilitating design of said read-out lens and permitting adjustment of focal length.

Abstract: An apparatus is described for reading an optical information structure arranged in tracks. By the use of a substantially rotationally symmetrical element having an annular radiation-attenuating peripheral portion cross-talk between the tracks as a result of obliquity of the information structure is substantially reduced.

Abstract: An optical system characterized in that a plano-convex lens for guiding onto a disk a light beam emitted from a semiconductor laser, and a prism for deriving reflected light from the disk are unitarily formed.

Abstract: Recovery from a record of data recorded in an information track, comprising depressed areas of a given width, a given depth, and variable length, alternating along the length of the track with relatively non-depressed areas, is effected by an optical playback system. The playback system employs means for focusing light from a laser source on the information track as a light spot having a diameter which is diffraction limited. The focusing system includes an independent light source (e.g., laser) which impinges on the surface of the record as a circular spot which illuminates a plurality of elongated tracks. The circular spot is imaged by a lens system on to a detector plane which is positioned at a plane which is conjugate to the record surface.

Abstract: Recovery from a record of data recorded in an elongated information track, comprising undulations representative of the data is effected by an optical playback system. In the system, the data is recorded within two substantially different frequency bands. The optical playback system has a dual response characteristic to provide improved response at the two different frequency bands. A modifying means interposed in the light beam path shapes the light beam to effect this dual response characteristic (i.e., two different bandwidth responses).

Abstract: A record carrier is disclosed having an optically readable information structure comprising trackwise arranged information areas, as well as an apparatus for reading said record carrier. By using two mutually perpendicularly polarized beams components for reading and by giving the information areas of adjacent track portions a different geometries such that areas of one geometry can be read in an optimum manner by only one of the beam components and is virtually not observed by the other beam component, the track distance can be reduced without increasing the crosstalk, so that the information content of the record carrier is increased.