Abstract: An optical pickup apparatus used in an optical data recording/reproducing apparatus for reading/reproducing data on an optical recording medium, including a light source, a diffracting device configured to transmit a light beam and to diffract a light beam reflected from the optical recording medium, an optical device having a reflecting portion and a transmitting portion configured to reflect one part of the light beam emitted from the light source and to transmit another part of the light beam to the optical recording medium and from the optical recording medium, and a photodetecting device to detect the light beam from the optical recording medium for signal light detection, and the light beam reflected by the reflecting portion of the optical device for monitor light detection of the light source.

Abstract: A method and device are described for writing an optical record carrier, in which a mark representing recorded data is written in a phase change layer of a record carrier by a sequence of radiation pulses. A trailing power level (t) having a value higher than the erase power level (e) is introduced after a last write pulse 3 in a sequence. Additionally, the power level of the last write pulse 3 in a sequence may be raised. This results in a reduced jitter of the marks written, especially when writing at high recording speeds.

Abstract: An optical disc that has a recognition mark area behind a recorded area and in which the last data in the recorded area is stably accessed, the recognition mark area can be accessed without bringing about an abnormal state, and the first data in a succeeding recorded area, if it exists, is stably accessed. An unrecorded area (5) is provided outside the recorded area (4) of the optical disc (1). A mark area (6) is provided between the recorded area (4) and unrecorded area (5). A recognition mark area (6d) is provided in the mark area (6) in order to recognize the boundary between the recorded area (4) and the unrecorded area (5). In the mark area (6), first and second buffer areas (6b and 6c) are provided respectively in front of and behind the recognition mark area (6d).

Abstract: The present invention relates to an apparatus and method for detecting non-recording regions of an optical recording medium for recording data or reproducing the recorded data by detecting header regions of the optical recording medium.

Abstract: When information is reproduced in an optical disk of high recording density or of low recording density, a main beam and sub-beams are emitted onto adjacent tracks. The main beam has a shape longer in a direction perpendicular to the tracks. When the optical disk of high recording density is reproduced, cross talk components from adjacent tracks included in signals reproduced from reflection light of the main beam are canceled by using signals reproduced from reflection lights of the sub-beams. When the optical disk of low recording density is reproduced, information is reproduced with a beam. Thus, two types of optical disks can be reproduced with a simple structure in a compatible way. In the cross talk canceling, discrimination marks formed along the tracks at constant distances are reproduced, and a time difference between the main beam and the sub-beams is corrected precisely by using track jump and detection of discrimination marks.

Abstract: In the context of mirror modulation (56, 90, 104) extraction during track seek or jump modes of an optical disc reading device (12), such as a DVD ROM, a mirror averaged level (i.e. the dc level (52) of the RF envelope (34)) is held so that the mirror modulation (90) is seen as a swing below a set mirror rebias level (86) at an output of a mirror amplifier (72), as shown in FIG. 3. With the holding of the dc level (52) by a ground-referred capacitor (302) during seek operation of the device (12), a first input (nin) to the mirror amplifier varies with the mirror modulation, whereas a second input (pin) to the mirror amplifier (72) does not vary. This phenomenon enables the top level of a RFRP signal (82) to be defined by the mirror rebias level (86) and the mirror component swing (during seek operation) to be optimized and always to occur below the mirror rebias level (86).

Abstract: To permit reproduction of a CD-R and the reproduction of a DVD in a compatible manner, both the aberration introduced by a substrate of a DVD having a 0.6 mm thickness and the aberration introduced by a substrate of a CD having a 1.2 mm thickness are reduced by a lens shape design where corresponding substrate thicknesses of the inner and outer regions of the objective lens are made different, and providing, in the inner region thereof, a protruding circular phase shifter and, also in a verge of the inner region, an annular phase shifter. The aberration of the objective lens in the CD reproduction was further decreased and the NA was increased up to 0. S, so that the recording of the CD-R was made possible.