Abstract: The address information of DVD-R or DVD-RW discs should be identified more accurately. Therefore, the detector is implemented with a sample/hold device for storing a reference value to be used for a sampling window. An optional integrator is used for comparing the integrated signal with a reference value to decide on the presence of a land pre-pit. The timing for controlling both the sample/hold device and the integrator is derived from a phase locked loop that is locked to the incoming groove wobble signal (TWin) by performing a clock multiplication with a predetermined factor. Advantageously, no band pass filter has to be included, which would need to be tuned according to the variations of the disc speed. Furthermore, the proposed land pre-pit detector is less affected by variations of the input amplitude, as no limiter is used.

Abstract: In an optical disc apparatus for reading data from an optical disc, levels of photo-detecting signals outputted from a plurality of photo-detecting areas of a photo-detector are adjusted to be substantially even for canceling error components due to positioning error of the photo-detector on an optical pickup. Analogous signals outputted from the photo-detecting areas of the photo-detector are amplified by amplifiers and converted to digital signals by A/D converters. A processor takes the converted digital signals and adjusts gains of the amplifiers with using the digital signals.

Abstract: Information is represented on the track or tracks of a record carrier by marks organised into bit cells having a constant bit length Bl. For indicating the track, the record carrier has a servopattern in which a winding number is coded in each winding of the track. The ratio between the track pitch and the bit length is determined in such a way that the increase of the length of the windings corresponds between consecutive windings to an integral number of bits. Thus, the position of an information block somewhere in the track is determined from the ratio and the winding number in a simple manner and with great accuracy, because no rounding errors are produced when a computation using integers is performed.

Abstract: Provided is an optical probe array head device in which a single optical detector or a plurality of optical detectors are disposed to each of the optical probes constituting an optical probe array having a plurality of apertures. The optical detectors are arranged to surround the aperture so as to be able to efficiently detect scattering of a feeble near-field light enabling similtaneous detection of a multipilicity of optical signals. In this device, an optical lens system necessary for optical detection can be omitted by integrating the optical probe array and the optical detectors. In addition, the output signals from the optical detectors can be utilized for conducting position control of the optical probe array head.

Abstract: The invention relates to a device for CD reproduction with variable speed or direction, in particular devices compatible with a CD player, such as, for example, DVD players which are likewise suitable for the playback of CDs, or corresponding CD-ROM drives. The invention is based on the fact that the data or information read from the CD are read into a buffer memory at a rate which, as a rule, is higher than is required for real-time reproduction. Data read into the buffer memory (RAM) in a continuous sequence are then used for CD reproduction with variable speed by means of subsampling or oversampling. For the purpose of reverse reproduction, groups of subcode words are successively read from the buffer memory by changing the order within the groups and are reproduced as a continuous reproduction data stream.

Abstract: There is provided an apparatus for compensating for an eccentricity of an optical disc, including a driver on which an optical disc is mounted for rotation, an optical head for emitting optical beams to the optical disc and receiving optical beams reflected from the optical disc, a mover to which the optical head is secured and which moves in a radius-wise direction of the optical disc, a track cross generating circuit which receives a track error signal from the optical disc and transmits a track cross pulse, and a controller which receives the track cross pulse to thereby determine an eccentricity of the optical disc in view of the optical beams reflected from the optical disc, and controls a rotational frequency of the optical disc in accordance with the thus determined eccentricity. The apparatus provides an advantage that an average transfer rate is increased for the long run.

Abstract: An information recording/reproducing apparatus includes a detector circuit for detecting a state of reflection light from the recording medium, a control circuit for calculating a radiation power used for writing the information in the recording medium, in accordance with the reflection light state, a pulse generator circuit for generating record pulse information in accordance with the radiation power, and an optical driver circuit for converting the record pulse information into optical information in accordance with the radiation power and driving the optical head to record the light information into the recording medium. Accordingly, the apparatus records information by applying light from an optical head to a record area of a recording medium and changing a state of the record area and reads the information recorded in the record area.

Abstract: A coding method for high-capacity storage medium is provided. The the physical location of the code is arranged in an annulus area at inner side of the inner most edge of the compact disk and/or the lead-in area such that the storage medium is accessible in the existing CD-R/CD-RW. The recording time of the existing CD-R/CD-RW can be expended from 80 to 100 minutes.

Abstract: The present invention provides an optical disc recording/reproduction apparatus and method capable of carrying out an accurate recording or reproduction when using a lens unit consisting of at least two lenses, which comprises: first drive means for driving both of the first lenses and the second lens in a focusing direction; second drive means for relatively driving the second lens with respect to the first lens in the focusing direction; focus servo means for carrying out focus servo by driving the first drive means so as to drive both of the first lens and the second lens in the focusing direction; and jog mode adjustment means for driving the second drive means after the focus servo is locked, so as to carry out a jog mode adjustment of the position of the second lens with respect to the first lens.

Abstract: A programmable writing system for an optical disk drive which is adaptable for pulse position modulation (PPM) and pulse width modulation (PWM) pulse generation. The writing circuit is responsive to a PPM/PWM mode command for generating programmed laser pulse signals. Specifically, a pattern detector is responsive to the PPM/PWM mode command for detecting input data. The detected data is provided to a pulse selector for selecting programmed pulse power and/or duration values, which operate a pulse generator to set pulse power levels and/or to set the duration of the generated laser pulse signals. In PWM mode, the pattern detector provides a toggle signal with each detected signal and the pulse selector responds to the toggle signal to alternate between providing mark pulse power and/or duration values and providing space duration values to thereby provide alternating mark and space signals.

Abstract: An information recording device having a light source unit including a plurality of laser light sources which are substantially linearly arrayed and independently driven, a deflecting unit for periodically deflecting a plurality of beams of laser light emitted from the light source unit in a direction crossing that of an array of the beams, and an image forming optical system for focusing the plurality of laser beams from the deflecting unit on a photoreceptor. In the information recording device, optical units for reducing divergence of the laser beams are provided in connection with the laser light sources of the light source unit.

Abstract: An optical disc apparatus for recording, reproducing or erasing an information signal by converging a light flux onto a recording layer through a transparent substrate. The apparatus includes one or a plurality of optical heads having a plurality of objective lenses whose aberrations have respectively been corrected for a plurality of disc substrates of different thicknesses, a cartridge for enclosing the optical disc, a discrimination hole which is formed on the cartridge, and a sensor for detecting the opening/closing state of the discrimination hole and for generating a discrimination signal. In accordance with the result of the discrimination as to the thickness of the loaded optical disc, the objective lens, in which the occurrence of the aberration is smallest, is used, so that the information signal can preferably be recorded, reproduced or erased onto/from the optical discs having different substrate thicknesses.