Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: A drive apparatus has vertically movable blocks on opposite lower front portions of a cartridge holder. On a base incorporated in the drive apparatus, there is provided a slide plate which moves when a disk cartridge is inserted in the drive apparatus. The slide plate has a cam for raising the blocks. A positioning pin and a pushing switch are located on the upper surface of each block. Each pushing switch has two switch elements. That one of the pushing switches which is located on the right block outputs "0, 0" when a single-sided disk cartridge is inserted upside down, "1, 1" when the single-sided disk cartridge is inserted correctly, and "0, 1 " when a double-sided disk cartridge is inserted.

Abstract: An information recording and reproducing apparatus for copying information from a master medium to a plurality of copying media, including a master medium reproducing unit for reading information from the master medium; a plurality of copying-medium recording unit for writing the information read from the master medium onto copying media; and a copying operation controlling unit for controlling the above-described recording and reproducing units; wherein a copying process is started when the copying operation controlling unit detects the mounting of a master medium into the master medium reproducing unit. At the end of a copying process, successful media are automatically ejected from the apparatus, whereas unsuccessful ones remain in the apparatus without being ejected, so that a user can easily know which media are successful and which ones are unsuccessful.

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: Apparatus for recording opto-magnetically information on an opto-magnetic record medium in the form of the direction of the magnetization stored in a magnetic layer including an objective lens for projecting a laser light beam onto the magnetic layer of the opto-magnetic record medium, a device for generating a bias magnetic field which is applied to the magnetic layer in a direction perpendicular thereto, a supporting device for supporting the objective lens movably in a focusing direction parallel to an optical axis of the objective lens as well as in a tracking direction perpendicular both to the optical axis and an information track direction, and a driving device for moving the objective lens in the focusing and tracking directions to perform the focusing and tracking control.

Abstract: In order to detect the position of a lens holder held resiliently by a pair of plate springs and fitted with an objective lens, a sensor is fitted in a through hole made in at least one of a pair of permanent magnets enclosing this lens holder and forming a closed magnetic circuit and the position holding the objective lens in a predetermined position is controlled with the output of the above mentioned sensor at the time of starting and ending the movement of the pickup.

Abstract: A device for detecting the abnormality of an optical pick-up head has a laser diode for emitting a light beam through an optical system to a reference reflective region formed at a predetermined portion of an optical disk, a photosensor for receiving a reflected light from the reflective region through the optical system, and a photosensor for detecting directly the light amount of the laser diode. The difference or a ratio of the detection signals of the photosensors is obtained, and the difference or the ratio is compared with a predetermined value. When the compared result exceeds a predetermined value, the result is decided to be an abnormality of the pick-up head.

Abstract: An input signal containing a base line which fluctuates to a great extent is detected or restored by comparing the input signal with reference levels which are shifted in accordance with the fluctuation of base line. The input signal is sampled at a variable sampling rate and an average of sampled values for a predetermined period is derived to produce a profile signal which resembles accurately the fluctuation of the base line. The profile signal thus obtained is added to upper and lower threshold voltages to produce the reference levels which have been corrected in accordance with the fluctuation of the base line of input signal.

Abstract: In a system for detecting defects on an optical surface, a disk to be inspected is mounted on a turntable, and is attracted on the surface of the turntable. On the disk is provided an optical head having an objective lens located at its focal point on the surface of the disk. A laser beam emitted from a laser unit is projected through the optical head onto the disk, is reflected on the disk, and is then directed through the optical head to a photo detector. The optical head is moved in the radial direction of the disk as the turntable is rotated, and the disk is helically scanned by the laser beam. Only a defect signal is extracted from an electrical signal generated from the photo detector in a defect signal generator. The defect signal is compared in a data processing unit, and is converted to defect information of different size.

Abstract: A disc drive apparatus for driving a disc selected from discs of various diameters with and without a central hole comprises: a turntable with a hole at the center of rotation thereof; a turntable support for rotatably supporting the turntable; a motor for driving the turntable; a centering member to be detachably inserted in the hole of the turntable and for mounting a disc with a central hole; a plurality of elastic disc support members which are coaxial with the center of rotation of the turntable, which extend from the surface of the turntable, and which form a plurality of annular shapes; centering index marks, disposed on the turntable, for centering a disc without a central hole; a vacuum pump; and suction channels, one end of which is open to the surface of the turntable and the other end of which is connected to the vacuum pump, for fixing on some of the disc support members the disc selected from discs of various diameters with and without a central hole and placed on some of said disc support membe

Abstract: In order to read out information recorded on a disc rotating at a constant angular velocity by means of a pick-up head movably arranged in a disc radius direction, a head position on the disc is detected to obtain a position signal representing a distance from a disc center to the pick-up head, and then a pulse signal having a frequency corresponding to the position signal thus obtained is generated. A detection signal supplied from the pick-up head and the pulse signal are supplied to an AND gate and pulses of the gated out pulse signal are counted by a counter. The number of the counted pulses represents correctly a length of the information recorded on the disc irrespective of position of the information on the disc.

Abstract: A system for focusing an optical head onto a flat surface has a mechanism for moving the optical head in the direction of the optical axis of the head and a mechanism for moving an objective lens in the optical head in the direction of the optical axis of the lens. A laser beam projected from the objective lens of the optical head is reflected on the flat surface, is reflected on the beam splitter, and is introduced into a detector unit. The detector unit thus generates a focusing signal having a level responsive to the distance between the objective lens and the surface. The optical head is lowered by the mechanism for moving the optical head in accordance with the focusing signal when it passes a predetermined point, and is operated to locate the focal point of the objective lens on the surface. Thereafter, the mechanism for moving the optical head becomes inoperative, and the mechanism for moving the objective lens is operated.

Abstract: An apparatus for detecting optically defects in object such as original glass disc for use in manufacturing video and audio discs by projecting a laser light flux onto the object includes an objective lens for focussing the incident laser light flux onto the object as a small light spot, the laser light flux passing through the objective lens at only its central portion. When the object has no defect in the light spot area, the laser light flux is regularly reflected by the object surface, but when the object includes a defect in the light spot area, the light flux is scattered by the defect. The directly reflected and scattered light fluxes are collected by the objective lens and are then separated from each other by means of a small mirror arranged in an optical axis of the directly reflected light flux. The directly reflected and scattered light fluxes thus separated are received by first and second light detectors.