Abstract: An optical disc device includes an optical head for recording/reproducing information to and from an optical disc. The optical disc has two primary recording areas. On a first recording area of the two primary areas, the optical head records information so that the linear density of information is maintained constant. On a second recording area of the two primary areas, the optical head records information so that the spacing between adjacently recorded information increases with increasing radial position of the head or the recording position is further removed from the center of the optical disc. A substitute area is allocated such that the optical head records information in this substitute area when a defective memory portion portion is detected in the first and/or the second recording area during production or recording.

Abstract: An apparatus for optically recording data on a recording medium having data recording tracks consisting of a number of blocks each including a header area in which a block number is recorded and a data area in which data is to be recorded. Consecutive block numbers are recorded on consecutive blocks. The apparatus reads out the block number from the header area, discriminates whether or not the block number read consecutively changes during a recording mode, and stops recording when a nonconsecutive change in block number is detected. Data recording and reproducing operations are performed with a laser the operation of which is controlled by a laser control circuit. A malfunction detecting circuit monitors varies laser operating parameters as well as the commanded laser operating mode and causes the laser to be turned off upon detecting a malfunction of the laser.

Abstract: In the initial operation phase of a data recording apparatus, a controller detects the output signal of a position detector, thus determining whether or not a data objective lens of an optical head is facing the non-storage region of an optical disk. If the lens faces the data non-storage region, the controller turns on a semiconductor laser, whereby the laser emits a laser beam onto the disk. The lens is moved in its axial direction, thereby focusing the beam. The beam emitted from the laser is detected by photodetectors. If this beam is too intense, the controller turns off the laser.

Abstract: A document filing apparatus is provided with a main unit for outputting parallel bit data, and a display device coupled to the main unit through an interface cable having a plurality of bit transmission lines. The display device comprises a multiplier circuit for multiplying the frequency of a clock pulse at a predetermined frequency, a parallel-in/serial-out shift register for receiving an image signal obtained by finely scanning a document, via the interface cable, as parallel image data, and for converting the parallel image data into serial image data in synchronism with a multiplied clock pulse signal from the multiplifer circuit, and cathode-ray tube for displaying image data obtained from the shift register as an image.

Abstract: An overlay recording prevention device for an optical disc apparatus detects a signal corresponding to a recording pit of a recorded track. This signal is detected from a photoelectric signal of an optical head when a tracking error occurs in the recording mode and a beam spot is shifted onto an already-recorded track. A high-level recording laser beam is stopped in response to this detection signal.

Abstract: In a data recording and reproducing apparatus and method, a modulator is provided for MF-modulating recording data and a pulse converter generates a pulse signal having pulses which have a predetermined pulse width and which are synchronous with the leading and trailing edges of the pulses of the signal from the modulator. An optical head, a peak detector, a flip-flop circuit and a demodulator are also provided. The optical head radiates a high-energy laser beam, or a recording beam, to an optical disk in response to the pulse signal from the pulse converter, thereby recording the data on the disk. To reproduce the data, the optical head continuously emits a low-energy laser beam to the disk. The beam reflected from the disk is converted into an electrical signal. The peak detector detects the peaks of the electrical signal and generates a pulse signal having pulses which are synchronous with the peaks of the electrical signal.

Abstract: An output stabilizing device for semiconductor laser oscillator is provided with an optical sensor for converting a monitor laser beam emitted from a semiconductor laser oscillator to a monitor signal. A monitor signal from the optical sensor is supplied to an envelope detector by which a minimum value envelope of the monitor signal is detected by the envelope detector. The minimum value envelope is compared with a reference signal for setting a level of a playback laser output in the comparator. The modulating signal is added to the compared signal from the comparator, i.e., the difference signal. The drive current corresponding to the added signal from the adder is supplied to the semiconductor laser oscillator.

Abstract: An automatic focusing device includes an optical head which comprises a focusing lens system and an optical sensor. The focusing lens system focuses a reading laser beam or a recording laser beam on an optical disk. The optical sensor generates photoelectric signals which correspond to the sections of a beam spot formed by a laser beam reflected from the optical disk. Record signal components corresponding to a recording laser beam are removed from the photoelectric signals by switch circuits. The photoelectric signals no longer containing record signal components are supplied to envelope detectors. The envelope detectors generate envelope signals each formed of signal components which correspond to a laser beam reflected from the surface of the optical disk. According to the difference between the envelope signals the focusing lens system is driven to thereby focus a laser beam on the optical disk.

Abstract: An optical disk apparatus has a detector for detecting absence of an optical disk in a prescribed position, a detection circuit for detecting non-rotation of the disk and an AND circuit for producing a logical product of the outputs from the detector and detection circuit. The detector comprises a light-emitting diode and a light-receiving element. An output signal from the AND circuit is supplied to a beam source driver/control circuit, thereby turning off a beam source.

Abstract: An optical head is mounted on a carrier of a linear motor, and is moved at a high speed to a desired track, i.e., a target position, of an optical disk by the linear motor. In the optical head, a laser oscillator for generating a laser beam, a tracking unit for tracking a laser beam and a focusing unit for focusing a laser beam onto an optical disk are integrally assembled.

Abstract: A single laser beam emitted from a laser generator driven by a laser driver in a record mode is alternately switched between a recording beam with large power and a tracking beam with small power. The switched beam is focused onto an optical disc through a laser beam transmitting section and then is reflected from the optical disc. The reflected laser beam from the optical disc is received by a pair of photo detecting elements in a two-divided way. Pulsate signal components with peaks corresponding to the recording beam contained in the output signals produced from the photo detecting elements are removed by sample-hold circuits in a wave-shaping section. A level difference between the output signals from the wave-shaping section is detected by a differential amplifier. The output signal from the differential amplifier, that is, a tracking control signal, drives a drive section to move an optical head.

Abstract: A beam scanning type electronic copying apparatus is provided in which document information is read out according to a beam reflected based on a scanning laser beam, the laser beam is modulated according to the document information and a record medium is exposed while being scanned. The laser beam scans the document and record medium simultaneously through an aconstooptic element which permits simultaneous beam diffraction and beam modulation. The readout of the document information and recording are simultaneously effected using the same optical system.