Abstract: An optical recording/reproducing apparatus capable of using disc cartridges of at least two different sizes and/or a naked disc, on only one tray. The optical recording/reproducing apparatus is also capable of recording and/or reproducing information on/from one of the discs mounted on the tray by automatically detecting the disc cartridges and/or the naked disc positioned on the tray.

Abstract: A light beam emitted from a light source is split into three light beams by diffracting the light beam by using a diffraction grating. The three light beams are reflected by the first side of a plane-parallel plate. The reflected light beams are projected onto an optical disk. The three signal light beams are reflected on the optical disk and returned to the plane-parallel plate in the form of three signal light beams. The plane-parallel plate allows part of the signal light beams to transmit therethrough and to reach a first photo detector. Further, the plane-parallel plate reflects the signal light beams on the second side and allows the reflected light beams to pass therethrough before reaching a second photo detector. The first photo detector receives the central light beam. The second photo detector receives the side light beams.

Abstract: A regenerating device for an optical recording medium which includes a detector preferably consisting of a charge modulation device and cell groups disposed in a matrix configuration, readout switches, a column selecting device for selecting the readout switches provided at every column on the basis of inputted column-address information, and a row selecting device for selecting cells in a specific row on the basis of inputted row-address information. The regenerating device further includes a readout device for defining, by time sharing, a cell region in a predetermined position of all of the cells disposed in the detector so as to read out detecting signals by time-sharing from these cells. The regenerating device controls a servo-control device controlling an optical head by using the detected signal in the detector, and furthermore, reads information recorded in a medium by using a reading device.

Abstract: A tracking control target position adjusting track is provided on a recording carrier, where the track contains a preliminarily recorded first position-adjusting signal adjoining one side of track and a second position-adjusting signal adjoining the other side of track. While the reproduction position set on the target-position adjusting track, the tracking control apparatus adjusts the tracking-control target position based on reproduced first and second position-adjusting signals. As a result, the tracking control apparatus can precisely adjust the tracking control target position, thus providing quite satisfactory interchangeability with the corresponding apparatuses.

Abstract: An apparatus for recording compressed digitized information to an optical disc by reading the digital data into a memory for transient storage. The digital input data thus written into the memory are sequentially read out of the memory and into an encoder at a transfer rate faster than the input transfer rate where the digital data are arranged in discrete clusters of record units including cluster-linking groups such that each record unit can be interleaved independently and without affecting other record units. The interleaved record units are then recorded onto an optical disc. Reproduction of the record units from the optical disk is carried out by reversing the process.

Abstract: An optical disk drive unit has an objective lens for converging light emitted from a light source and irradiating the converged light to an optical information recording medium; an objective lens holder for holding the objective lens; a carriage for supporting elastically the objective lens holder thereto; and a magnetic circuit for performing a seeking operation and having a magnet and a yoke arranged outside the carriage and extending along a radial direction of the optical information recording medium, the magnetic circuit having a movable coil fixed to the carriage so as to surround one side of the yoke. The movable coil is formed in a polygonal shape in cross section and is constructed such that one carriage side of the movable coil is located below a moving part of the objective lens and another side of the movable coil opposite to the one carriage side thereof is set to be longer than the one carriage side.

Abstract: The optical recording/reproducing apparatus provided with a dividing optical element which divides a part of the light from a light source and projects the divided light to a moving stage on which an objective lens is mounted, a reflecting optical element which is mounted on the moving stage and reflects the projected light from the dividing optical element, and a photodetector which detects the reflected light from the reflecting optical element, wherein the deviation amount of the moving stage from a reference position is detected on the basis of output of the photodetector. Since the condition when the reflected light is incident upon the photodetector is changed in consequence to the positional deviation of the reflecting optical element as the moving stage is moved, the deviation amount of the moving stage is detected on the basis of the output of the photodetector. The deviation amount of the moving stage can be detected at all times, thereby achieving good tracking control.

Abstract: In order to make a track jump from the present track to a target track, accelerating pulses and decelerating pulses are sequentially fed to a tracking actuator driving an objective lens condensing and radiating light beams to a disc, then a tracking servo is switched on, a tracking error signal within a fixed time after the decelerating pulses is monitored with a zero cross comparator or the like and further the decelerating pulses can be additionally output to the tracking actuator in response to the output of this comparator. In case it is hard for the light spot to teach the target track, the light spot will be pulled to the target track side by switching on the tracking servo and, in case it passes over the target track, the light spot will be suppressed in passing over the switching on the tracking servo and the movement of the light spot will be decelerated by the additionally output decelerating pusles to pull the light spot into the target track.

Abstract: Method and apparatus for control of positioning of a recording/playback head or other controlled object. When a controlled object reaches the vicinity of a target position, the control system is switched from operation as a velocity control system to operation as a position control system. By using state variables of the controlled object at that time, coefficients corresponding to the detected state variables are determined from characteristics of the controlled object which are determined in advance. By using the determined coefficient values, initial values upon start of position control of the position control system are set, and positioning control is then carried out.