Abstract: In a method of detecting track crossings on an optical disc, a light source irradiates a light beam onto an optical disc having guide tracks in the form of a recess and the light beam is reflected and diffracted into a zero order light beam and positive and negative primary light beams. The light beams are defocused so as to produce interference patterns between the zero light beam and the positive and negative primary light beams. The interference patterns are detected by a four split light detector disposed between two parts of a two split detector. The outputs of the detectors are fed to an adder and to a subtractor for producing a sum signal and a difference signal respectively. The sum signal and difference signal are fed to a phase detector. Defocusing of the light beams is effected by a focusing coil to which is fed the amplified output of an adder of a reference signal controlled by a control circuit.

Abstract: An apparatus for recording and reproducing optical information is disclosed.

Abstract: A magneto-optical information system writes and erases information on and from a magneto-optical information recording medium under application of a bias-magnetic-field to the recording medium according to writing and erasing command signals. A differential amplifying circuit differentially processes the writing and erasing command signals to produce a differential output signal, and a constant current power amplifying circuit produces a stable drive current according to the differential output signal. A bias-magnetic-field generating coil is driven by the stable drive current so that a stable bias-magnetic-field is applied to the information recording medium according to the differential output signal.

Abstract: An optical information recording and reproducing system comprises a light source for emitting a working beam from a front end thereof and a monitoring beam from a rear end thereof, an optical system control circuit, a loop gain adjusting circuit and a photo detector. The monitoring beam emitted from the rear end of the light source is detected by the photo detector, and the loop gain of the servo loop control circuit for the focusing and/or tracking is automatically adjusted by means of the loop gain adjusting circuit according to the detected signal so that a desired closed loop control of the working beam can be performed according to the operation modes and the light beam power variation.

Abstract: In an optical magnetic recording and reproducing apparatus including a disc clamp member and a magnetic field biasing device, the disc clamp member and the magnetic field biasing device are pivotably supported by separate supporting members so as to undergo pivotal movement independently of one another with respect to a disc cartridge holder. This enables a compact arrangement in which the disc cartridge holder is compactly accommodated beneath the disc clamp member and the magnetic field biasing device during the loading of a record disc.

Abstract: An information recording reproducing apparatus adapted to receive a cartridge therein which contains a disc is provided. The cartridge is loaded in the apparatus on a cartridge transfer body which moves horizontally and then vertically. A disc clamp arm is pivotably supported on the cartridge transfer body, and a clamp head disposed at one end of the clamp arm clamps the disc when the cartridge transfer body descends vertically to be positioned on the turn table.

Abstract: In an optical measuring device including a laser ray source, a polarization prism, an objective lens to condensing parallel ray to the surface of a substance to be measured, and divided photo-sensor means to detect reflected ray, the divided photo-sensor means is two divided photo-sensors, to eliminate noise effect caused by the laser ray source.

Abstract: A device for retaining a lens by a lens holding frame is disclosed, which comprises a plurality of non-adhesion portions formed on an outer periphery of the lens an inner periphery of the frame, and an adhesive inserted into portions other than the non-adhesion portions between the lens and the frame.

Abstract: A disc jacket, especially for a photo-magnetic disk which records, reproduces and erases information, has a single opening configured to receive both a recording head and a central spindle. The opening extends along the whole radius of the disk to enable effective use of a larger area of the disc. The opening is opened and closed by a pair of shutter blades which automatically open when the disk jacket is inserted in an information recording and reproducing apparatus.

Abstract: A lens mounting assembly includes a frame to retain a lens. In the frame, an axially opened annular recess is formed. The lens has an annular axial projection which is received in the recess. Sufficient clearance is formed between the recess wall and the lens periphery to permit thermal expansion of the lens. Interfitting between the projection and the recess enables mechanically accurate radial and axial positioning between the lens and the frame. Elastic means, i.e., elastic adhesive or elastic member, retains the lens to the frame allowing thermal expansion and/or contraction of the lens relative to the frame.

Abstract: A method of detecting defects formed on an optical record medium for use in an optical information recording and reproducing apparatus. The method comprises steps of deriving light output signals reflected from the record medium at the time of information writing, comprising the light output signals with reference signals which are set to a plurality of desired levels, and logically operating the compared output signals thereby detecting and evaluating the defects formed on the surface of the record medium.

Abstract: A beam tracking system is used in an optical information recording and/or reproducing apparatus to optically track a record medium track. An objective lens irradiates an optical beam onto the record medium and is driven by a lens actuator to sweep the optical beam in a coarse mode relative to a predetermined track of the record medium. A carriage moves relative to the record medium for carrying the objective lens thereon and is driven by a carriage actuator to sweep the optical beam in a fine mode relative to the track. A detector detects the reflected optical beam during the sweep of the optical beam to produce a tracking signal representative of the deviation of the optical beam from the track. A pair of control circuits are connected to control the lens and carriage actuators respectively to effect the alignment of the optical beam with the track according to the tracking signal.

Abstract: Apparatus for compensating for physical deviations due to warp and surface deflections in optical discs during optical recording and reproducing operations. Focus error signals are developed corresponding to the individual addresses of the physical deviations and the extent of deviation from the in-focus position of the focusing lens by moving a light pickup under control of a microcomputer radially of the disc so that N given radial pitch intervals are defined relative to the record surface of the optical discs and M circumferential address positions of each rotation of the disc. The detector detects the focus error signal values at M.sub.x N.sub.x address locations which are memorized in a memory storing M.times.

Abstract: A high temperature microscope having an optical system and a chamber system is disclosed. Frictional rotation of the peep window provided in the chamber system is caused together with frictional rotation of a first flange, in which the peep window is provided, and a second flange, which surrounds the first flange and is surrounded by a stationary third flange. It is thus possible to greatly delay the limit of the period, during which observation of the object can be made, due to fogging of the peep window. Double wall sealing ring members are provided between the first and second flanges and between the second and third flanges of the chamber of the high temperature microscope. The space between the double wall sealings can be evacuated through an inverted T-shaped ventilation hole provided in the second flange. Thus, the chamber can be evacuated to a superhigh vacuum higher than the vacuum degree obtainable in the chamber of the prior art high temperature microscope.

Abstract: An optical power stabilizing device for use in an optical information recording and reproducing apparatus is disclosed. The device comprises a light source for generating a light output power having a non-linear characteristic to a driving current or voltage thereof, a light detection circuit coupled to the light source for detecting a part of the output light to generate an electric signal, a signal treating circuit connected to the light detection circuit for treating the detected electric signal, a compension circuit connected to the signal treating circuit for compensating the current or voltage to be supplied to the light source in accordance with the temperature variation, and a control circuit connected to the signal treating circuit and the compensation circuit for controlling the current or voltage to be supplied to the light source.

Abstract: The invention relates to a method and an apparatus for generating a data recording area signal in order to define an appointed data recording area on a data storing medium which has a multitude of sectors with high information density recorded by means of beam irradiation. The index signal derived from the detected index pattern in a sector is used together with a clock signal supplied.

Abstract: A solid state image sensor having row lines connected to a vertical scanning circuit, column lines connected to a horizontal scanning circuit, a video line selectively connected to the column lines, and pixels arranged at cross points between the row and column lines, each pixel including a static induction transistor having a drain connected to the ground, a source connected to a column line and a gate connected to a capacitor formed by a gate electrode connected to the gate, a photoconductive film applied on the gate electrode and a transparent electrode applied on the photoconductive layer. The transparent electrode may be divided into a plurality of parts each of which extends in a row direction and is connected to respective row line.

Abstract: An automatic analyzing apparatus for automatically effecting chemical analysis on a sample of blood, urea or the like dependent on measurement items by measuring the light absorption degree of a reaction liquid through a reaction vessel, comprising a reaction liquid photometric unit, a photometric unit independent of the reaction light photometric unit and operative to measure beforehand the light absorption degree of the reaction vessel per se or the reaction vessel containing a reagent or dilute liquid, and means for correcting the light absorption degree of the reaction liquid measured at the reaction liquid photometric unit on the basis of the light absorption degree of the reaction vessel per se or the light absorption degree of the reaction vessel containing the reagent or dilute liquid measured at the independent photometric unit.

Abstract: Method for detecting a focus condition of an imaging optical system by using a surface acoustic wave device is disclosed. A light receiving element array formed by a plurality of light receiving elements receives a light flux transmitted through at least a part of an image formed by the imaging optical system. Then, outputs of said light receiving elements are processed on real time by means of a Fourier transform device including a surface acoustic wave device, a convolver, etc. so as to derive an image sharpness and/or an image lateral shift, both of which are used for a focus detection. Therefore, as compared with a conventional focus detection method, it is possible to perform the focus detection in a fast and accurate manner by a simple and small construction.

Abstract: An anti-reflection coating for an optical component and a method of forming the same are disclosed. The anti-reflection coating is formed on a substrate for an optical component by subjecting a mixture of an evaporating material and 10-30% of SiO.sub.2 to vacuum evaporation at room temperature without heating the substrate. When the anti-reflection coating is a single layer, a mixture of MgF.sub.2 and 10-30% of SiO.sub.2 is used as the evaporating material. When the anit-reflection coating is a multi-layer structure, a mixture of a fluoride or a silicon oxide and 10-30% of SiO.sub.2 for a first layer, and a mixture of a fluoride or an oxide and 10-30% of SiO.sub.2 for middle and last layers are used as the evaporating material.