Abstract: An optical disc reproducing device 10 has an optical pickup 11 for reading out digital data recorded on an optical disc, an amplitude detection circuit 18 for detecting the amplitude of a wobble component signal passed by a band pass filter 14, and a tilt detection, target value setting and drive signal generation circuit 23 for carrying out detection of the tilt quantity.

Abstract: A signal recording/playback apparatus includes a recording data converter. The recording data converter converts on a data pattern having a large influence on adjacent tracks on an optical disk, and outputs the converted data to an optical pickup. Specifically, by performing a data converting process in which, for a data pattern having a predetermined length of at least consecutive bits having identical values, part of the bits is inverted based on a conversion table, the recording data converter compensates a recording operation. Alternatively, instead of inverting the bits, by controlling the output power and pulse width of a laser, the recording operation is compensated. The signal recording/playback apparatus includes a played-back data converter. In the data playback mode of the signal recording/playback apparatus, the data converted by the recording data converter is identified and decoded into the original data by the played-back data converter. The played-back data converter outputs the original data.

Abstract: Light beams are irradiated from a head 2 onto an optical disc 1 including a recording layer and a reproduction (readout) layer to open, at the reproduction layer, detection window smaller than irradiation range of light beams to thereby read out recording information of the recording layer. A resolution detecting section 15 detects resolution on tile basis of signal level of a reproduction signal reproduced from the optical disc 1. A signal level detecting circuit 11 of the resolution detecting section 15 detects signal level of a specific mark length signal corresponding to specific mark length data in the reproduction signal which has been reproduced, and a resolution calculating circuit 12 calculates resolution on the basis of the detected signal level of specific mark length.

Abstract: A phase error detection apparatus and method is disclosed whereby a data signal is played back at a high S/N ratio from a magneto-optical disk making use of a ghost signal by magnetic domain wall displacement detection while the playback laser poser is kept at an optimum level. First, the laser power is controlled so that the time delay of a ghost signal from a data signal may be equal to a fixed multiple of a data detection clock. Thereupon, a laser power control section searches for a point at which the amount of jitters generated is small based on a RF signal. Then, the playback laser power is adjusted so that the time delay amount of the ghost signal from the data signal may be the fixed multiple n=5 of the clock nearest to the phase delay amount set in advance of a ghost which appears in the isothermal region with a laser power with which an optimum signal characteristic is obtained.

Abstract: A frequency demodulating circuit for demodulating a frequency-modulated signal expressing digital data. The circuit includes a waveform shaping circuit for acquiring a binary signal from the frequency-modulated signal and a detector for decoding the binary signal and response to clock signals to obtain the digital data. A circuit also includes a clock signal generating circuit for generating the clock signals which have a frequency of the frequency-modulated signal corresponding to “one” of the digital data and a frequency higher than the frequency of the frequency-modulated signal by a multiple, which corresponds to a “zero” of the digital data.

Abstract: A recording and/or reproducing apparatus employing a disc-shaped recording medium in which difficulties so far met in detecting an address in case a groove of the recording medium exhibiting superior recording characteristics and those met in detecting an address in case both a land and a groove of the recording medium as recording tracks may be resolved. A recording and/or reproducing unit (5) includes an optical head for illuminating the laser light converged as spots on an optical disc 6 and for receiving the return light reflected and diffracted from the optical disc (6). An address information generating unit (7) generates the address information from the return light received by the optical head in the recording and/or reproducing processing unit (5). A tilt compensation unit 16 detects the inclination (tilt) of the optical head relative to the optical disc (6) to correct the tilt of the optical head in accordance with the tilt detected.

Abstract: The invention provides an optical shaping apparatus comprising a stage 1 having a light transmitting portion 11, an irradiator 4 disposed below the stage 1, a table 3 disposed above the stage 1 and having a resin supply hole provided with an opening in a rear surface thereof, a lift mechanism 2 for driving the table 2 upward and downward, an optical shaping control unit 8 for controlling the operation of the lift mechanism 2 and the irradiator 4, and a resin supply tank 5 for supplying an uncured resin to the resin supply hole of the table 3. The uncured resin is filled into a space between the table 3 or a cured resin layer formed on the rear surface of the table 3 and the stage 1 to form an uncured resin layer of predetermined thickness, and the resin layer is irradiated with light over a region thereof in conformity with contour line data. The apparatus is shortened in shaping time, simplified in construction and compacted.

Abstract: An optical information recording medium, an optical information recording method and an optical information recording apparatus are able to prevent one laser beam of two laser beams from affecting the other laser beam by an offset. In an optical disc in which a groove whose one-side is wobbled or modulated only is sequentially formed by turning on or off one laser beam of two laser beams in accordance with a modulation signal and desired data is recorded by the groove, since the groove is formed by wobbling the one laser beam in such a manner that the one laser beam may not affect the other laser beam, a light intensity of the one laser beam is not added to a light intensity of the other laser beam, which is not wobbled by a wobbled amount so that the other-side of groove may be protected from the influence of the offset.

Abstract: A frequency demodulating circuit, optical disk and preformatting device having a decoder for decoding a bit “0” and a bit “1” for reproducing address information recorded as a wobble groove. The decoder determines whether an output is a digital “1” or a digital “0” so that even if the waveform of the reproduced signal is erratic or unstable due to a defect, a digital “1” or a digital “0” can be correctly identified by utilizing window pulses. Changes in the slop of a zero cross point of the groove wobble are prevented from occurring by making the groove wobble amplitude fluctuate according to the signal frequency modulation which also greatly reduces jitter and allowing satisfactory acquisition of the address information. Oversampling clock signals of biphase bits are generated by frequency division of data clock signals.

Abstract: According to the present invention, when a land-groove recording method is adopted, thermal crosstalk between a land and an adjoining groove is suppressed effectively. Inhomogeneity of a recording layer between the land and groove is suppressed effectively. A substrate for optical recording media comprises groove-like concave parts (2) and convex parts each created between adjoining concave parts. A border sidewall (4) between a concave part and an adjoining convex part (2) has a plurality of sidewall planes, that is, at least a first sidewall plane (41) that leads to the bed of the concave part and a second sidewall plane (42) that leads to the apical plane of the convex part. The first sidewall plane meets the bed of the concave part at an angle ranging from 120° to less than 180°. The second sidewall plane meets the bed of the concave part at an angle ranging from 90° to 110°.

Abstract: An optical disk having a plurality of substantially concentric tracks, each of which includes a plurality of segments each comprising a servo area ARs provided with servo pits for giving servo information to a disk drive and a data area ARd. Identification marks SGM, ADM, STM1, STM2 are recorded in the servo area ARs. The identification marks SGM, ADM, STM1, STM2 provide information for identifying the respective segments depending on the recording position in the servo area ARs.

Abstract: A format of a recording medium suitable for a larger capacity, a higher transfer rate, and integration of pits/lands/grooves is provided. In a first method, in a recordable and reproduceable area, a twin-track structure of lands/grooves is configured such that tracks on which lands become recording tracks and tracks on which grooves become recording tracks form a double spiral. In a read-only area, pits are arrayed such that tracks in the radial direction of the disk are formed in a data area. In a second method, in a recordable and reproduceable area, a land/groove-alternate track structure is configured such that grooves become data recording tracks in the circular track next to the circular track in which lands become data recording tracks, and lands become data recording tracks in the next circular track. In the read-only area, pits are arrayed such that tracks in the radial direction of the disk are formed in the data area.

Abstract: An equalizer used for an optical reproducing apparatus performs an optimal equalizing operation in accordance with the spatial frequency without needing an electrical equalizer. The optical reproducing apparatus reproduces the reproducing data in the following manner. A detector is provided for receiving reflected light from a disc. The detector is divided into a plurality of light receiving areas by a line perpendicular to the light receiving direction corresponding to the disc track direction. Then, calculations are made on the outputs from the respective light receiving areas to specifically correct the spatial frequency characteristics. The calculated signal is then decoded.

Abstract: A magneto-optical disc in which, for preventing damage to a recording layer in case the foreign matter is sandwiched between a magnetic field modulation head and the magneto-optical disc, or the magnetic field modulation head is contacted for some reason with the magneto-optical disc, the direction of magnetization of the recording layer formed on a polycarbonate substrate, designed for transmitting the laser light, is switched by the magnetic field modulation head. The magnetic field modulation head is mounted floating in a direction opposite to the direction of incidence of the laser light from an optical head converged on an objective lens. A diamond-like carbon (DLC) protective film, composed of a thin DLC film, is provided on the surface of recording layer towards the magnetic field modulation head.

Abstract: A format of a recording medium suitable for a larger capacity, a higher transfer rate, and integration of pits/lands/grooves is provided. In a first method, in a recordable and reproduceable area, a twin-track structure of lands/grooves is configured such that tracks on which lands become recording tracks and tracks on which grooves become recording tracks form a double spiral. In a read-only area, pits are arrayed such that tracks in the radial direction of the disk are formed in a data area. In a second method, in a recordable and reproduceable area, a land/groove-alternate track structure is configured such that grooves become data recording tracks in the circular track next to the circular track in which lands become data recording tracks, and lands become data recording tracks in the next circular track. In the read-only area, pits are arrayed such that tracks in the radial direction of the disk are formed in the data area.

Abstract: A magneto-optical disc in which, for preventing damage to a recording layer in case the foreign matter is sandwiched between a magnetic field modulation head and the magneto-optical disc, or the magnetic field modulation head is contacted for some reason with the magneto-optical disc, the direction of magnetization of the recording layer formed on a polycarbonate substrate, designed for transmitting the laser light, is switched by the magnetic field modulation head. The magnetic field modulation head is mounted floating in a direction opposite to the direction of incidence of the laser light from an optical head converged on an objective lens. A diamond-like carbon (DLC) protective film, composed of a thin DLC film, is provided on the surface of recording layer towards the magnetic field modulation head.

Abstract: An optical disk having a plurality of substantially concentric tracks, each of which includes a plurality of segments each comprising a servo area ARs provided with servo pits for giving servo information to a disk drive and a data area ARd. Identification marks SGM, ADM, STM1, STM2 are recorded in the servo area ARs. The identification marks SGM, ADM, STM1, STM2 provide information for identifying the respective segments depending on the recording position in the servo area ARs.

Abstract: An optical disc has a base formed by resin, and a reflection layer formed on the base. On the base, servo areas where servo pits P1, P2 for providing servo information for sample servo system are formed at predetermined angular positions of respective tracks on the base. Further, data areas where data pits Pd for providing data information accessed by the optical disc drive operative on the basis of the servo pits P1, P2 are formed between the respective servo areas. In addition, in the servo area and the data area which are adjacent to each other, between servo pit P2 disposed at the position closest to the data area and data pit Pd disposed at the position closest to the servo area, anchor pit Pan neglected in the optical disc drive is provided.

Abstract: An optical recording medium on which information data is to be recorded and on which an n-th recording track is located at a distance from the (n-1)th recording track preceding the n-th recording track in a recording region which is narrower than the diameter of a spot of a light beam radiated on the recording area, with recording data obtained on logical processing with recording data recorded on the (n-1)th recording track being recorded on the n-th recording track for increasing the storage capacity of information data, is disclosed. A return beam of a light beam radiated across two neighboring recording tracks on the optical recording medium is detected by a detector having first and second light receiving sections having a boundary line extending parallel to the recording track of the optical recording medium for reading out the information recorded on the optical recording medium based on the level of a sum or difference signal of the output signals of the first and second light receiving sections.

Abstract: An optical recording medium on which information data is to be recorded and on which an n-th recording track is located at a distance from the (n-1)th recording track preceding the n-th recording track in a recording region which is narrower than the diameter of a spot of a light beam radiated on the recording area, with recording data obtained on logical processing with recording data recorded on the (n-1)th recording track being recorded on the n-th recording track for increasing the storage capacity of information data, is disclosed. A return beam of a light beam radiated across two neighboring recording tracks on the optical recording medium is detected by a detector having first and second light receiving sections having a boundary line extending parallel to the recording track of the optical recording medium for reading out the information recorded on the optical recording medium based on the level of a sum or difference signal of the output signals of the first and second light receiving sections.