Abstract: An offset compensation apparatus for a tracking error signal in an optical recording reproduction apparatus adds or subtracts a signal, which is proportional to the intensity of a read head laser beam, to or from a tracking error signal (which indicates the difference between a track of an optical disk and a a read head laser beam spot on the optical disk) so as to cancel offsets occur in the tracking error signal that are in proportion to the intensity of the read head laser beam and, thus, compensates for the offset in the tracking error signal. Since the offset compensation signal is also indicative of the amount of laser light irradiated to the optical disk, the offset can be compensated easily and accurately with a small scale simple circuit arrangement rather than using the larger-scale and more conventional divider attenuator combination of the prior art.

Abstract: An optical recording medium driving apparatus has the first high-pass filter for outputting a low frequency component removed signal by removing a low frequency component from a reproduction signal varying depending on a reflected light beam from the optical recording medium. The low frequency component removed signal changes due to transient response just after an access operation starts. Zero voltage is inputted to the second high-pass filter during a tracking operation while a voltage having a negative polarity which is substantially the same amplitude as the AC component of the low frequency component removed signal is inputted to the second high-pass filter. The first high-pass filter has the same time constant as the second high-pass filter. Just after the access operation starts, the negative voltage has the same transient response as the output of the first high-pass filter.

Abstract: An optical disk drive which discriminates whether a light spot is incident on a groove or on an area therebetween by eliminating a pulse that appears in a binary envelope signal when the light spot passes a level section. The elimination is carried out based on an ODF section detecting signal, the ODF section detecting signal being a level section detecting signal which is produced by detecting a level section (ODF section) of the optical disk. The detection is carried out by differentiating an envelope signal, which is the envelope of an electric signal corresponding to the amount of light reflected from the optical disk. Accordingly, even if the optical disk in use has interrupted grooves, the optical head can be accurately moved to a desired track located on a land or on a groove.

Abstract: An optical disk recording and reproducing apparatus in which during coarse access, an adjustable target speed is obtained using a speed offset value stored in a speed offset memory. The speed offset value being determined between a plurality of reference velocities and a plurality of adjustable offset velocity values. The system also performs fine access within a defined distance from the optical head to the designated track upon completion of the coarse access mode. The speed offset values are continually updated by to improve the accuracy of the coarse access operation saving overall access time.

Abstract: A track access operation system for an optical recording and reproducing apparatus using a medium having a plurality of guide grooves and ID sections utilized for identifying a particular guide groove. The intensity of reflected light and transmitted light from each of a plurality of light beams projected on the recording medium is monitored for determining the location of the beam on the disk. The system is designed such that at least either the plurality of light beams or the plurality of ID sections of the guide grooves are so arranged such that more than half of the light beams or more than half of the ID sections do not overlap in a parallel direction along the guide grooves whereby the number of light beams simultaneously projected on the ID sections is limited to less than half of the total number of light beams projected on the recording medium.

Abstract: A track jumping apparatus for an optical disk pickup which can detect a tracking error signal in performing a track jump, and determine a time of acceleration or deceleration of a jump signal by comparing the tracking error signal with a reference level, the track jumping apparatus comprising storing device for storing of standard values corresponding to the kinds of track jumps, standard value selecting device for selecting a standard value corresponding to a kind of track jump in performing the track jump, reference level setting device for setting a reference level so that the ratio of the reference level to a peak value of the tracking error signal agrees with a value based on the standard value selected by the standard value selecting device in performing the track jump, and standard value amending device for amending the standard value in the storing device selected at that moment according to a state of the tracking error signal at the end of the track jump.

Abstract: A feedback control apparatus in an optical recording and reproducing device for recording, reproducing and/or erasing data from an optical recording medium projects a light beam emitted from an optical head onto the optical recording medium. The apparatus includes an actuator for controlling the illuminating conditions of the light beam projected onto the optical recording medium, a detection unit for detecting the illuminating conditions of the light beam projected onto the optical recording medium, and a control amplifier for driving the actuator in accordance with a detection signal outputted from the detection unit, thereby controlling the illuminating conditions of the light beam projected onto the recording medium.

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 extra magnetic field positioning apparatus includes a motor which does not have stable points for defining the extra magnetic field. An encoder is provided which is rotated with the motor and individually has the information which indicates rotating displacement and the information which indicates rotating position. Further, a sensor detects the information indicating the rotating position recorded on the encoder, and another sensor detects the information indicating the rotating displacement recorded on the encoder.

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 objective lens-driving unit comprising a lens supporting means for supporting the objective lens having an optical axis vertical to a recording medium on which light beams converge through the objective lens so as to attain optical recording, optical playing and optical erasing of information on the recording medium; at least one driving means for driving said lens supporting means in the tracking direction; a driving means for driving said intermediate supporting means in the focusing direction, wherein said tracking direction-driving means comprises a magnetic circuit that produces magnetic flux in the circumferential direction of the recording medium, and a tracking direction-driving coil that is positioned to cross a gap formed in the magnetic circuit to thereby receive an electro-magnetic force due to an interaction between the magnetic field of the magnetic circuit and the current passing through said coil, said tracking direction-driving coil being positioned within the excitation area of the magnet