Abstract: An optical disc player having an optical pickup records and retrieves information on an optical disc while the optical disc is rotating. A rotation pulse is generated each time the optical disc rotates through a prescribed angle. A rotation frequency data representing a frequency of the rotation pulse is also generated. A servo processor performs servo processing for rotation control on the optical disc in accordance with the rotation frequency data. A sampling pulse generator performs computational processing on an input data signal to generate a sampling pulse. The sampling pulse generator also corrects the rotation frequency data based on a phase error between the sampling pulse and the rotation pulse to use a corrected rotation frequency data as the input data signal. Another servo processor performs servo processing for repetitive control on the optical pickup using the sampling pulse.

Abstract: The present invention provides an optical disk device which optimizes recording power level used when recording data. A controller records test data in a test region of an optical disk and evaluates reproduced signal quality of the test data, so as to determine an optimum recording power level Po (OPC). Subsequently, the controller uses reflected light intensity level B obtained when recording data to make adjustments to the optimum recording power level Po, thereby obtaining recording power level P. The recording power level P is adjusted such that Bm/Pn=constant, where m and n are positive rational numbers satisfying m<n. When m=1, the value of n is greater than or equal to 1.5 and no larger than 10.

Abstract: An operation of a recording/reproducing portion is controlled by a control portion so as to record data in a predetermined recording region on a recording medium, and perform update recording in the predetermined recording region in accordance with occurrence of update information of the data. The control portion further has a function of controlling the recording/reproducing portion so as to record an update portion of data in a temporary storage region in a part of the recording medium and record an update flag showing whether the predetermined recording region has been updated with the update portion or has not been updated with the update portion in an update flag region, and in update recording with respect to the predetermined recording medium, successively performs operations of recording the update portion in the temporary storage region, setting the update flag in a non-updated state, recording the update portion in the predetermined recording region, and setting the update flag in an updated state.

Abstract: An information reading and recording apparatus includes a super-resolution cut-off filter having an annular metal reflection film at its center portion and disposed immediately before one of two objective lenses with a higher NA. When reading DVD, the one objective lens with a higher NA with the super-resolution cut-off filter disposed therebefore is positioned at the optical path. When reading CD, the other objective lens with a lower NA is positioned at the optical path. The laser beam reflected by a disk follows backward the incoming optical path to pass through a half mirror, and is received by a photo-detector to be converted into an electrical signal.

Abstract: An information recording apparatus that records information with a substantially constant linear density in a circumferential direction of a recording medium having a disk shape, includes variable velocity recording control means, recording power modification means, recording power storage means, and initial recording power value setting means.

Abstract: An optical information reading apparatus includes a semiconductor laser, a beam splitter, a collimating lens, a super-resolution cut-off filter, an objective lens having a high numerical aperture, and a photodetector. The super-resolution cut-off filter is disposed immediately in front of the incident side of the objective lens. The photodetector is a well-known eight-division photodetector with a signal processing circuit, reads recorded information and also outputs tracking and focusing control signals to a control circuit. The laser beam is separated into a 0-th order laser beam and ± primary laser beams, which are made incident on the objective lens, pass therethrough, and are made incident on the recording surface of a disk. The 0-th order laser beam is used to read information and to control focussing while the ± primary laser beams are used to control tracking.