Abstract: An information recording and reproducing apparatus performs information recording and reproducing on an optical disc having a recording track wobbled by a predetermined frequency. The apparatus includes an optical pickup which irradiates a laser light on the optical disc and receives the laser light reflected by the optical disc to output an electric signal corresponding to the laser light, a push-pull signal generating unit which includes a sample-hold unit and generates the sample-hold push-pull signal and the non-sample-hold push-pull signal from the electric signal, a sample-hold circuit which samples and holds the push-pull signal, a recording clock generating unit which generates a recording clock synchronized with the wobble signal based on the sample-hold push-pull signal during recording and based on the non-sample-hold push-pull signal during reproduction, and a phase adjusting unit which adjusts the phases of the non-sample-hold push-pull signal and the sample-hold push-pull signal.

Abstract: There are provided an information write device and an information read device enabling to generate highly accurate contrast signals. When a main light spot Pc is located at the center of the a groove G, the light spot Pc and sub light spots Psa, Psb are each adapted to radiate a disc DSC such that the sub light spots Psa, Psb radiate positions displaced from the center of the land L. The reflected beams of light from the disc DSC caused by the radiation with the light spots Pc, Psa, Psb are detected to generate push-pull signals each corresponding to the light spots Pc, Psa, Psb, respectively, in accordance with each of the detected signals. Furthermore, a signal to be obtained by amplifying an addition signal, given by adding the push-pull signals each corresponding to the sub light spots Psa, Psb, with a predetermined amplification factor K/n, and a push-pull signal corresponding to the main light spot Pc are added to thereby generate a contrast signal.

Abstract: A recording timing setting apparatus for setting a recording start timing for recording first recording information onto a recording medium on which second recording information is previously recorded and on which a plurality of synchronization signals are recorded in advance. The second recording information includes a plurality of information units each including synchronization information. The recording timing setting apparatus includes: a first detecting device for detecting the plurality of synchronization signals; a second detecting device for detecting the synchronization information included in the second recording information; a generating device for generating a timing signal for predicting the detection timings of the plurality of synchronization signals, on the basis of the synchronization information detected by the second detecting device; and a timing control device for setting the recording start timing by using the timing signal.

Abstract: A filter generates a received-light signal LAD2 from which impulse components TR included in a received-light LAD1 have been removed. A filter generates a received-light signal LBC2 from which impulse components TR included in a received-light LBC1 have been removed. A subtracter subtracts a received-light signal WBC from a received-light signal WAD, thereby generating a radial push-pull signal WPP. A comparator compares the radial push-pull signal WPP from which the impulse components have been removed with a reference level VT, thereby detecting a land prepit.

Abstract: An information recording and reproducing apparatus performs information recording and reproducing on an optical disc having a recording track wobbled by a predetermined frequency, such as a DVD-RW.

Abstract: A code judging apparatus is provided with: a detecting device (11) for optically detecting an information code including at least identification information to individually identify a writable record medium (DK), in which record information can be written, from the writable record medium to thereby output an output signal; a moving device (19) for moving the detecting device onto a set area, which is an area on the writable record medium where the information code is supposed to be recorded; and a judging device (19) for judging whether or not the information code is recorded on the writable record medium, in accordance with the output signal outputted from the detecting device moved on the set area.

Abstract: A pre-pit detection unit having pre-pit detection circuits (600 and 700) respectively corresponding to beam intensity in mark and space periods that are provided in parallel on the output side of a push-pull circuit (500) for generating a pre-data signal. The pre-pit detection unit finally outputs the OR of the outputs of both pre-pit detection circuits as a pre-pit detection signal (l). An AGC circuit (601 and 701) for making the maximum amplitude of a radial push-pull signal (d) obtainable from said push-pull circuit coincide with a reference value is provided in the preceding stages of pre-pit detecting comparators (606 and 706) in the respective pre-pit detection circuits.

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: In a disc player, a CAL pattern is recorded in a disc-like optical recording medium during a recording stand-by time period, which is yielded by a difference between a data rate in inputting information to a disc player 50 and a recording rate in recording information into the optical recording medium. The CAL pattern is reproduced from the optical recording medium, the reproduced pattern is evaluated, and an irradiation intensity of a laser beam is optimized for recording information in the optical recording medium, by a laser-output controller 30.

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 disc player having a prepit detecting circuit which can correctly detect prepits even if phases or amplitude levels of a plurality of read signals read out from a recording disc are deviated from each other. A phase difference between a first read signal and a second read signal read out by first and second reading elements arranged in two regions divided along the direction of recording tracks of a recording disc is detected. A first phase correction read signal is obtained by adjusting the phase of the first read signal by an amount according to the phase difference. A differential value between the first phase correction read signal and the second read signal is outputted as a prepit detection signal.

Abstract: A recording time point setting method and apparatus are provided. The recording time point setting method is a method of setting a recording time point for recording an information piece into one of a plurality of predetermined areas on a recording medium on the basis of a plurality of marks. The marks are pre-recorded on the recording medium at predetermined intervals. The locations of the marks correspond to the locations of the predetermined areas, respectively. The locations of the predetermined areas are predetermined on the basis of a time length of the information piece. In this method, firstly, at least one of the marks is detected. Then, an expectation signal is generated on the basis of the time length of the information piece, and then, a time point at which an output of the expectation signal is started is synchronized with a time point at which the at least one of the marks is detected.

Abstract: Before information is recorded onto an information record medium by irradiating a light beam, a test signal is recorded for each of a plurality of unit test record regions with a plurality of different record powers. Then, the test signal recorded in each of the unit test record regions is reproduced, and further an optimal record power for the light beam is selected on the basis of a condition of the reproduced test signal.

Abstract: A code judging apparatus is provided with: a detecting device (11) for optically detecting an information code including at least identification information to individually identify a writable record medium (DK), in which record information can be written, from the writable record medium to thereby output an output signal; a moving device (19) for moving the detecting device onto a set area, which is an area on the writable record medium where the information code is supposed to be recorded; and a judging device (19) for judging whether or not the information code is recorded on the writable record medium, in accordance with the output signal outputted from the detecting device moved on the set area.

Abstract: Provided are a method and apparatus for detecting an occurrence of erroneous recording in recording information to be recorded into a DVD-R. The information consists of a plurality of ECC blocks each including a predetermined number of recording sectors. In the DVD-R, synchronizing information, accomplished by wobbling of groove tracks, and positional information, such as pre-pits, are previously recorded. Both the synchronizing information and the positional information are detected, then a synchronizing timing signal showing a time at which the synchronizing information is detected and a positional timing signal showing a time at which each ECC block is assigned to be recorded are produced. The synchronizing timing signal produced during an interval defined by the successive two positional timing signals is counted in number, and a state signal for estimating the occurrence of the erroneous recording is produced on comparison between the counted number and the predetermined number of the recording sectors.

Abstract: A composite vinylidene chloride copolymer composition excellent in processability which comprises a vinylidene chloride copolymer A having a molecular weight of not less than 50,000 and not more than 300,000 and a vinylidene chloride copolymer B having a molecular weight of not less than 5,000 and not more than the smaller one of either 0.8 times the weight average molecular weight of the vinylidene chloride copolymer A or 80,000, and a monolayer film which comprises the composite vinylidene chloride copolymer composition and is excellent in various properties including barrier property, non-extractability by oily foods and high frequency sealability, and is suitable as a barrier packaging material and wrapping film used for ham, sausage and other like foods.

Abstract: A track search controller has three two-segment photodetectors, three subtracters associated respectively with the two-segment photodetectors, a processing circuit, and a servo control cirucit. Each of the photodetectors produces two output signals based on a light beam reflected from an optical disk. Each of the subtracters produces a differential output signal representing the difference between the output signals from the associated photodetector. The processing circuit generates an actuator position signal from the output signals from the subtracters. The actuator position signal contains a component indicative of a deviation of the actuator due to its vibration. The servo control circuit controls an actuator, which actuates a laser beam source, so that the actuator position signal will be of a constant value.

Abstract: A light spot position detector reliably effects spot-on-track detection even if the reflectivities of recording tracks and intertrack areas of an optical disk are substantially the same as each other. A tracking error signal used to control a scanning spot applied to the recording tracks on the optical disk is produced by mixing light spot position signals that are generated according to the three beam method and the push pull method from light beams reflected from light spots on the signal recording surface of the optical disk.

Abstract: There is disclosed an apparatus for detecting position of a light spot, suitable for the tracking control or the track-jumping control at the time of reproducing an optical disk. This light spot position detector has a circuit configuration featured below. Namely, three light beams are used to provide three push-pull outputs from the respective light beams to apply a predetermined operation to those push-pull outputs, thereby to generate a light spot position signal permitting discrimination as to whether or not the light spot is in the on-track state. Further, by gain controlling the light spot position signal thus generated, a suitable signal is permitted to be outputted even when a signal is undesirably attenuated for any reason.