Abstract: A optical disk recording and reproducing device capable of recording and reproducing data to or from an optical disk. Continuous signals representing continuous analog information such as audio and video information and discrete signals representing discrete data-information such as numerical data including program codes or character data are recorded dividedly in different recording regions provided on an optical disk including erasable or write once-type disks. The optical disk is rotated at a given linear or rotary angular speed under control by a disk rotation control device so as to simplify rotational control of the optical disk in accessing the information in the divided regions.

Abstract: An apparatus for recording and reproducing information on and from an optical disk includes a first control for producing a first control signal for controlling the rotational speed of a rotational driving apparatus, on the basis of the detected radial position; a judging apparatus which judges whether or not the reproduced signals are reproduced from a recorded region of the optical disk; a second control for producing a second control signal for controlling the rotational speed of the rotational driving apparatus, on the basis of the signals reproduced from the disk; and a switch apparatus which switches the circuit so that the rotational driving apparatus is controlled by the first control signal when the reproduced signals are not reproduced from a non-recorded region, and controlled by the second control signal when the reproduced signals are reproduced from a recorded region.

Abstract: The track counter for optical disk in accordance with the present invention, that counts the number of tracks a light beam passes upon when an optical head moves over an optical disk in the radial direction, comprises a passage signal generating circuit for detecting based on a reflected light of the light beam from the optical disk, that the light beam passed upon a track and for releasing a passage signal on that occasion, a counter that counts the passage signals released by the passage signal generating circuit, a count suspending circuit for forecasting that the light beam will pass upon a specific position of a track and for suspending the count by the aforementioned counter of the passage signals during this forecasted period, and a count value compensating circuit for assuming, when the count of the passage signals is suspended by the count suspending circuit, the number of tracks the light beam passed upon during that period, and for adding this assumed number to the count value of the counter.

Abstract: An magneto-optical memory device for recording, reproducing or erasing information by applying an optical beam such as a laser beam onto a magneto-optical recording medium, the magneto optical memory device including a recorded region detecting circuit for detecting information recorded region formed in the recording medium. In the memory, a timing control for recording, reproducing or erasing is performed with the use of one result obtained through detection of a synchronizing signal such as a sector mark indicative of a starting point of an information block and another result obtained through detection in the recorded region detecting circuit.

Abstract: A digital signal reproduction apparatus includes a first differential circuit for differentiating a reproduction signal reproduced from a recording medium. This differential circuit outputs a first order differential signal and second differential circuit differentiates the first order differential signal of the reproduction signal and outputs a second order differential signal. A comparator compares the second order differential signal with a predetermined level to produce a window signal. A peak detecting circuit detects zero-cross points in the first order differential signal and outputs a peak detecting signal. A gate gates the peak detecting signal with the window signal to output a reproduction data signal.

Abstract: An optical memory device for recording, reproducing or erasing information by applying an optical beam such as a laser beam onto a recording medium in which the optical memory device includes a recorded region detecting circuit for detecting information recorded in a specified region formed in the recording medium. The optical memory device also includes a timing control for recording, reproducing or erasing data with the use of one result obtained through detection of a synchronizing signal such as a sector mark indicative of a starting point of an information block and another result obtained through detection in the recorded region detecting circuit. The recorded region detecting circuit contains either of at least one peak hold circuit for detecting a peak level of the playback signal and a low pass filter for smoothing the playback signal, and a comparator for comparing an output obtained through the peak hold circuit or through the low pass filter with a reference voltage.

Abstract: A disc clamping device comprises a disc base on which to set a disc and which has a spindle for rotating the disc, and a disc holding member movable in the axial direction of the spindle. The disc holding member comprises a portion for pressing a disc with a centering hub and a portion to be engaged with the center hole of a disc with no centering hub.

Abstract: An automatic gain control device for use in an optical memory device has a circuit for producing an amplification control signal which is fed back to a gain control amplifier through a sample-hold circuit. A pulse train detection circuit is provided for detecting the pulse train indicating that the data stored are a on the optical memory device is being playedback. When the pulse train is detected, the sample-hold circuit is made inactive so that the amplification control signal is directly fed back to the gain control amplifier, and when the pulse train ends, the sample-hold circuit is made active to hold the amplification control signal obtained at the end of the pulse train and to produce the amplification control signal held in the sample-hold circuit.

Abstract: An analog signal switching device for use in an optical memory device having a recording/erasing mode and a mode other than the recording/erasing mode is disclosed. The switching device includes a source for producing a switch control signal which is HIGH during the recording/erasing mode and LOW during the mode other than the recording/erasing mode. An analog switch is provided for receiving a direct input analog signal and a held input signal and for providing as output the direct input signal during the LOW state of the switch control signal, and the held input signal during the HIGH state of the switch control signal by a switching operation.

Abstract: A sync signal detection apparatus is provided wherein a sync signal represents the top of recorded data. The sync signal includes a plurality of marks each having a different pattern from the pattern of any other mark. The apparatus is equipped with a circuit for sequentially detecting the patterns of the individual marks in a reproduction mode. Also, a circuit is provided generating a sync pulse at the top of the data in accordance with the address pattern of the mark after a predetermined number of marks are detected. The apparatus ensures accurate reproduction of the recorded data with a small number of bits and an increase in data reliability.

Abstract: An optical information recording and reproducing apparatus comprising: a circuit for focusing a light beam on a recording track of an optical disk having tracks formed spirally or concentrically; a circuit for recording the information on a track corresponding to the focused position of light beam on the track or reproducing information from on the track; a tracking control circuit for generating a tracking control signal for matching the focused position of the light beam with the track; a circuit for detecting deviation of the focused position of the light beam from the track and generating a deviation signal corresponding to the focused position of the light beam; a holding circuit for holding the deviation signal; a subtracting circuit for subtracting the held deviation signal from the tracking control signal; and a circuit for moving an objective lens for controlling the focused position of the light beam in response the output signal from the subtracting circuit.

Abstract: An improved three-dimensional driving arrangement of an objective lens or the like, which is so arranged that coils for focusing control, tracking control and tangential control in three directions re disposed in one magnetic gap for compact size, while the coils for the tracking control and tangential control are each formed to have a V-shaped cross section, with going passage arms of the coils being disposed in the magnetic gap, but returning passage arms of them being disposed outside the magnetic gap through four slit-like notches formed in a yoke, thus making it possible to drive the objective lens independently in three directions.

Abstract: A three-dimensional driving arrangement of an objective lens or the like, which is so arranged that coils for focusing control, tracking control and tangential control in three directions are disposed in one magnetic gap for compact size, while the coils for the tracking control and tangential control are each formed to have a V-shaped cross section, with going passage arms of the coils being disposed in the magnetic gap, but returning passage arms of them being disposed outside the magnetic gap through four slit-like notches formed in a yoke, thus making it possible to drive the objective lens independently in three directions.

Abstract: An objective lens drive/support mechanism in an optical disc player system includes an objective lens support member which is slidably and rotatably secured to a main shaft of the mechanism. An objective lens is supported by the objective lens support member at a position which is separated from the main shaft by a predetermined distance. The objective lens support member is driven to slide along the main shaft to perform the focus control, and the objective lens support member is rotated around the main shaft to perform the tracking operation. A symmetrically "8" shaped elastic damping member is tightly secured to the main shaft at the center of the symmetrically "8" shaped elastic damping member. Both ends of the symmetrically "8" shaped elastic damping member are fixed to the objective lens support member, whereby the single symmetrically "8" shaped elastic damping member conducts the damping operation in both the focal direction and the tracking direction.

Abstract: An optical bar code reader includes a recognition system for recognizing a bar code data even when none of a plurality of scanning beams extend over the entire width of a bar code label. A plurality of incomplete data each of which represents a portion of the bar code label are combined with each other by a composition circuit to get an estimated complete bar code data. A determination system is provided for detecting whether the read out data obtained from any scanning beam corresponds to the entire bar code data. If an affirmative answer is obtained by the determination system, such read out data is directly applied to the associated processing system without activating the composition circuit.