Abstract: An image display element includes an incident diffraction grating which diffracts incident light, and an outgoing diffraction grating from which light that has propagated through the light guide plate after being diffracted by the incident diffraction grating is emitted, the incident diffraction grating and the outgoing diffraction grating being each formed by a pattern of concave-convex formed on a surface of the light guide plate, and the image display element being obtained by joining the light guide plate and a cover glass protecting the pattern of concave-convex or two or more light guide plates with an air layer therebetween by a holding member, and being configured such that the light guide plate and the cover glass are formed by a plastic material, and the holding member has an air vent through which air in the air layer and outside air communicate.

Abstract: The optical module for optical height measurement includes a laser light source, an irradiation optical system, a detection optical system, and a detector. The laser light source is configured to irradiate the layer-structured specimen with a light beam. The irradiation optical system includes an objective lens. The objective lens is located to be approximately perpendicular to the layer-structured specimen. The detection optical system is configured to guide a reflected light reflected by the layer-structured specimen and a light passing through the objective lens and an aperture-restrictor-for-return to the detector. The aperture-restrictor-for-return is located immediately after the objective lens. The aperture-restrictor-for-return is configured to restrict the reflected light and cause only a light in a high NA region to pass through. The detector is configured to convert an entered light into a light detection signal. The detector includes a multi-divided detector array.

Abstract: An optical module for optical height measurement optically measures a height of a specimen and includes an irradiation optical system, two detection optical systems, and a light dividing element. The irradiation optical system includes a laser light source and an objective lens to irradiate the specimen with a light beam. The two detection optical systems each include a divided optical detector configured to detect a reflected light reflected by the specimen. The light dividing element is configured to guide the reflected light to the two detection optical systems. A light that has transmitted the light dividing element and a light reflected by the light dividing element are guided to the respective two detection optical systems. Intensity distributions of the transmitted light and the reflected light on the two detection optical systems are inverted in line symmetry.

Abstract: The optical module for optical height measurement includes a laser light source, an irradiation optical system, a detection optical system, and a detector. The laser light source is configured to irradiate the layer-structured specimen with a light beam. The irradiation optical system includes an objective lens. The objective lens is located to be approximately perpendicular to the layer-structured specimen. The detection optical system is configured to guide a reflected light reflected by the layer-structured specimen and a light passing through the objective lens and an aperture-restrictor-for-return to the detector. The aperture-restrictor-for-return is located immediately after the objective lens. The aperture-restrictor-for-return is configured to restrict the reflected light and cause only a light in a high NA region to pass through. The detector is configured to convert an entered light into a light detection signal. The detector includes a multi-divided detector array.

Abstract: An optical disc device includes an optical source for emitting an optical beam, an incident intensity control circuit for controlling an intensity of the optical beam emitted from the optical source, an objective lens for focusing the optical beam on an optical disc, an optical detector for receiving the optical beam reflected from the optical disc, and a servo signal generation circuit for generating a focus error signal from the optical detector, by this configuration, the optical beam is varied once to a third optical beam intensity to be present in between a first optical beam intensity and a second optical beam intensity when varying from the first optical beam intensity up to the second optical beam intensity different from the first optical beam intensity, and the incident intensity control circuit is controlled such that the variation of focus error signal is not exceeded over a predetermined range.

Abstract: An optical disc device includes an optical source for emitting an optical beam, an incident intensity control circuit for controlling an intensity of the optical beam emitted from the optical source, an objective lens for focusing the optical beam on an optical disc, an optical detector for receiving the optical beam reflected from the optical disc, and a servo signal generation circuit for generating a focus error signal from the optical detector, by this configuration, the optical beam is varied once to a third optical beam intensity to be present in between a first optical beam intensity and a second optical beam intensity when varying from the first optical beam intensity up to the second optical beam intensity different from the first optical beam intensity, and the incident intensity control circuit is controlled such that the variation of focus error signal is not exceeded over a predetermined range.

Abstract: An optical device wherein an optical component and a plurality of light emitting elements are mounted on an identical substrate, a level of a surface on which the optical component is mounted is different from that of a surface on which the light emitting elements are mounted by a step provided on the substrate, at least one plane vertical to the surface on which the optical component is mounted and located on a periphery of the substrate is opened, a reflecting surface, a transmitting surface or a diffraction grating surface of the optical component is provided along sides generated by the step provided in the substrate, optical axes of the plurality of light emitting elements of which polarization axes are in parallel with each other intersect with each other on the surface, and an exit light beam of the light emitting elements is emitted from the opened plane.

Abstract: An optical device wherein an optical component and a plurality of light emitting elements are mounted on an identical substrate, a level of a surface on which the optical component is mounted is different from that of a surface on which the light emitting elements are mounted by a step provided on the substrate, at least one plane vertical to the surface on which the optical component is mounted and located on a periphery of the substrate is opened, a reflecting surface, a transmitting surface or a diffraction grating surface of the optical component is provided along sides generated by the step provided in the substrate, optical axes of the plurality of light emitting elements of which polarization axes are in parallel with each other intersect with each other on the surface, and an exit light beam of the light emitting elements is emitted from the opened plane.

Abstract: An method to prevent excessive heat generation of the pickup actuator from occurring when a disk has a large eccentricity or planar vibration in a high-speed disk reproducing apparatus using an optical pickup. The disk reproducing apparatus has a status determining arrangement for monitoring a present actuator drive state, an analyzing arrangement for analyzing an output signal of the status determining arrangement, and disk rotational speed switching control arrangement for selecting disk reproducing speeds according to a control signal of the identification means, thereby lowering the reproducing speed when the eccentricity or planar vibration is large. Such invention prevents heat generation of the pickup actuator from occurring because high-speed reproduction can be performed when the eccentricity or planar vibration is small, and reproduction speed can be automatically reduced when the eccentricity or planar vibration is large.

Abstract: An optical reading/reproducing apparatus such as a compact disc (CD) player, and particularly a focusing system therefor, wherein the direction of one of the focal lines of the light spot on a light detector is set to be in parallel with the direction of track on the disc surface, a divide-into-four line of the light detector is set to be 45 degrees or a value close thereto with respect to the track direction, and an offset voltage is applied to a portion of the focus servo loop connected with the output unit of a focus error detector circuit. Owing to this structure, the optical parts can be easily mounted, a casing for containing them can be easily molded, and the apparatus can be mass-produced in small sizes.

Abstract: In a liquid crystal display device comprising a substantially rectangular liquid crystal display panel having segment electrodes provided along a first edge thereof and common electrodes provided along a second edge thereof orthogonal to the first edge, a segment circuit board extends along the first edge and is electrically connected with the segment electrodes, and a common circuit board extends along the second edge and is electrically connected with the common electrodes.

Abstract: An optical disc apparatus arranged so that a light beam from a laser light source is focused by an object lens and irradiated on an optical recording medium having thereon a mirror surface and tracks of a plurality of pits for recording data, and that a reflected beam from the recording medium is irradiated on an optical detector from which a signal on the recording medium is reproduced for maintaining a position of said object lens at an optical center axis by a tracking servo. The optical detector includes at least two adjacent photoelectric transducers providing outputs indicative of the reflected beam incident thereon, a device for producing a signal indicative of a difference between the outputs from the transducers, and a position detector for detecting the position of the object lens in a direction perpendicular to the tracks in cooperation with said difference producing device.

Abstract: A method and apparatus is disclosed for reducing optical noise in an optical information processing system having a single longitudinal mode laser which is converged on a record medium for detecting information stored on the medium. A range from 1-10% of the total emitted light per facet of the laser is fed back to an emitting point of the laser to minimize the occurrence of optical noise present in the light emitted from the laser.

Abstract: A tracking system for optically tracking information tracks formed on a recording medium, comprising a comparator which generates a trigger signal when the light beam scanning the information track is located over an information pit, and a sample holding circuit which samples a deviation signal caused by the difference of reflection light intensities on two photo detectors at that time. The deviation signal obtained when the light beam is located over the information pit includes smaller error component caused by the displacement of the object lens during the tracking control, whereby the accurate tracking control can be achieved.