Abstract: An information recording/reproducing apparatus irradiates a light beam on an optical disc on which pre-pits are formed, and performs recording and/or reproduction of information with respect to the optical disc according to a recording clock produced based on a wobble signal and a pre-pit signal. When recording information onto the optical disc having the pre-pits, a light beam is radiated to thereby extract the wobble signal and pre-pit signal. Then, according to the wobble signal and the pre-pit signal, a recording clock signal is produced, and information is recorded based on the recording clock signal. When producing a pre-pit signal, a push-pull signal is produced from the reflected light from the optical disc, and this signal is compared with a reference level to thereby detect a pre-pit. Here, when a pre-pit is not detected, the reference level is changed and the detection processing of the pre-pits is executed again.

Abstract: An optical recording device includes an optical pickup, an asymmetry detection circuit, and a microcomputer. The optical pickup corrects an aberration of an object lens based on an aberration correction value using a liquid crystal panel in the optical pickup, irradiates a laser beam of multiple stages of recording powers on an optical disk to form marks, and then reproduces the formed marks with a reproduction power. The asymmetry detection circuit detects amplitudes of RF signals of the marks reproduced by the optical pickup, calculates amplitude central values such that asymmetry takes a predetermined value, and determines an optimum recording power. The microcomputer performs spherical aberration correction to change a spherical aberration correction value from an initial value such that the optimum recording power takes a minimum value.

Abstract: An optically recorded information recording and/or reading apparatus which eliminates the influence of stray light occurring within an optical system. In a state or a focus state which is forcedly set to position a reading point outside the outermost periphery of a disk surface, and the signal level is adjusted in a signal combiner circuit such that a light receiving level at that time matches a desired level.

Abstract: A pre-pit detecting apparatus which, when a light beam is radiated onto an optical recording medium having a recording surface with pre-pits repeatedly formed between tracks, receives light reflected by the recording surface with first and second light receiving faces, obtains the push-pull signal corresponding to the light receiving signals for the first and second light receiving faces, samples the push-pull signal to collect sample data for a predetermined period, and sets a threshold value between the maximum value of data corresponding to a track and the minimum value of data corresponding to a pre-pit, of the collected sample data.

Abstract: A laser light intensity controller includes a polarizing beam splitter for passing most of one of an x-direction polarization component perpendicular to a direction in which a laser beam emitted from a light source travels and a y-direction polarization component parallel with the traveling direction and for reflecting a little portion of the one polarization component as monitoring light, and a photodetector for receiving the reflected monitoring light to generate a light intensity signal. The controller drives the light source in accordance with the light intensity signal. The photodetector reflects the other of the x-direction polarization component and the y-direction polarization component and is not sensitive thereto, and absorbs the one polarization component and is sensitive thereto.

Abstract: A laser light intensity controller includes a polarizing beam splitter for passing most of one of an x-direction polarization component perpendicular to a direction in which a laser beam emitted from a light source travels and a y-direction polarization component parallel with the traveling direction and for reflecting a little portion of the one polarization component as monitoring light, and a photodetector for receiving the reflected monitoring light to generate a light intensity signal. The controller drives the light source in accordance with the light intensity signal. An optical element which passes passing only the one polarization component is installed between the light source and the polarizing beam splitter.

Abstract: Linking gap detecting device and method in which a light beam is irradiated to an information recording track of an optical recording medium; a light detecting signal is generated by receiving reflected light of the light beam irradiated to the information recording track; a synchronous signal is detected from the light detecting signal; it is judged whether the existing interval of the synchronous signal lies outside a predetermined interval range or not; and the linking gap is detected on the basis of a result of the judgment.

Abstract: An optical pickup for reading information from a recording medium having a plurality of prepits or for recording information onto the recording medium is provided. The optical pickup includes: a light emitting device for emitting a light beam to the recording medium; a dividing device for dividing the light beam reflected by the recording medium into a first divided beam and a second divided beam; an astigmatism producing device for producing astigmatism in the first divided beam; a first light receiving device for receiving the first divided beam from the astigmatism producing device; and a second light receiving device for receiving the second divided beam from the dividing device.

Abstract: An optical pickup device including an optical system which includes a first optical path which introduces a laser beam emitted from a light source to a recording surface of an optical disc through an objective lens and a second optical path which introduces the laser beam reflected on the recording surface of the optical disc to an optical detector through the objective lens, and an optical element which is disposed at least in the first optical path such that the optical element is movable in the optical axis direction of the laser beam.

Abstract: An optical pickup device comprises an objective lens unit having an objective lens, a support member for supporting the objective lens and an objective-lens driving mechanism for driving the objective lens in a radial direction and a focusing direction of an optical disc in such a way that a light beam is focused on an information recording surface of the optical disc; and a main unit having an optical irradiation system which includes a light source for emitting a light beam and guides the light beam to the objective lens, and an optical detection system which includes a photo-sensor and guides reflected light from the information recording surface to the photo-sensor via the objective lens.

Abstract: An information recording/reproducing apparatus irradiates a light beam on an optical disc on which pre-pits are formed, and performs recording and/or reproduction of information with respect to the optical disc according to a recording clock produced based on a wobble signal and a pre-pit signal. When recording information onto the optical disc having the pre-pits, a light beam is radiated to thereby extract the wobble signal and pre-pit signal. Then, according to the wobble signal and the pre-pit signal, a recording clock signal is produced, and information is recorded based on the recording clock signal. When producing a pre-pit signal, a push-pull signal is produced from the reflected light from the optical disc, and this signal is compared with a reference level to thereby detect a pre-pit. Here, when a pre-pit is not detected, the reference level is changed and the detection processing of the pre-pits is executed again.

Abstract: In an error counting apparatus and method, there are provided a reproducing section for reproducing the optical disc and a counter for counting the error number of the pre-pit signal based on an output of the reproducing section. When it is detected that the reproducing section come up to the reproduction of the emboss portion, a counting operation of the counter is started in response to this detection. When it is detected that the reproducing section has reproduced the optical disc in the predetermined interval after the counting operation is started, the counting operation of the counter is stopped in response to this detection.

Abstract: An optically recorded information recording and/or reading apparatus which eliminates the influence of stray light occurring within an optical system. In a state or a focus state which is forcedly set to position a reading point outside the outermost periphery of a disk surface, and the signal level is adjusted in a signal combiner circuit such that a light receiving level at that time matches a desired level.

Abstract: An AR measuring apparatus receives the reflection light of an optical beam irradiated on an optical recording medium having a recording surface on which pre-pits are repeatedly formed between tracks by means of a first light receiving surface and a second light receiving surface, obtains a push-pull signal based on the difference between light receiving signals from the first and second light receiving surfaces, collects sample data by sampling the push-pull signals for a predetermined period of time, repeats the sampling for the predetermined period of time by a plurality of times, determines whether or not each data value corresponding to a pre-pit position of the sample data by the plurality of times is obtained by a predetermined number of times or greater, and when data values obtained by the predetermined number of times or greater are determined, calculates as an aperture ratio, a ratio between the minimum value and the maximum value of values corresponding to a pre-pit component of the data values obt

Abstract: An information recording apparatus (S) records record information onto an optical disc (1), which corresponds to a CLV (Constant Linear Velocity) method to keep a linear velocity of the optical disc constant when reproducing the record information from the optical disc.

Abstract: A plurality of light receiving detectors receive a plurality of segments of a beam returning from an optical disc when a reading beam of light is radiated to the optical disc. An optical pickup assembly produces a plurality of signals from the beam segments in accordance with, for instance, optical intensities of the beam segments. A level adjusting circuit adjusts signal levels of these signals such that each of the signal levels of the signals becomes equal to a reference level. The reference level is determined from at least one of the signal levels of the received beam segments.

Abstract: A pre-pit detecting apparatus which, when a light beam is radiated onto an optical recording medium having a recording surface with pre-pits repeatedly formed between tracks, receives light reflected by the recording surface with first and second light receiving faces, obtains the push-pull signal corresponding to the light receiving signals for the first and second light receiving faces, samples the push-pull signal to collect sample data for a predetermined period, and sets a threshold value between the maximum value of data corresponding to a track and the minimum value of data corresponding to a pre-pit, of the collected sample data.

Abstract: A pre-pit detecting apparatus which, when a light beam is radiated onto an optical recording medium having a recording surface with pre-pits repeatedly formed between tracks, receives light reflected by the recording surface with first and second light receiving faces, obtains the push-pull signal corresponding to the light receiving signals for the first and second light receiving faces, and binarizes the push-pull signal by using a threshold value to generate a pre-pit detection signal. It is judged which area of a plurality of areas including at least a not-yet-recorded area corresponds to a position of the recording surface where the light beam is radiated is performed to judge. Then the threshold value is set in accordance with the judgement result.

Abstract: A tilt servo control device of an apparatus for recording information on and reproducing information from an optical recording medium, the apparatus comprising an optical system for leading a laser beam emitted from a light source to a recording surface of the optical recording medium and a laser beam reflected by the recording surface of the recording medium to a split type photo detector and a read signal generator for generating a read signal in accordance with an output signal of the photo detector. The tilt servo control device generates a push-pull component signal including a differential component of output signals of respective split portions of the photo detector, generates a tilt error signal representing a tilt angle at a position of the laser beam irradiating the recording surface and an optical axis of the laser beam based on the push-pull component signal, and drives a tilt angle adjuster for adjusting the tilt angle so as to reduce the tilt error signal.

Abstract: An optical pickup device comprises an objective lens unit having an objective lens, a support member for supporting the objective lens and an objective-lens driving mechanism for driving the objective lens in a radial direction and a focusing direction of an optical disc in such a way that a light beam is focused on an information recording surface of the optical disc; and a main unit having an optical irradiation system which includes a light source for emitting a light beam and guides the light beam to the objective lens, and an optical detection system which includes a photo-sensor and guides reflected light from the information recording surface to the photo-sensor via the objective lens.