Abstract: An optical information storage medium according to the present invention has at least one information storage layer. The optical information storage medium has a management area that stores at least one unit containing control information about the optical information storage medium. The control information includes a format number, which provides information about at least a write strategy type and a write pre-compensation type, and a write strategy parameter, which provides information about the magnitude of shift in an edge position, or variation in the pulse width, of a write pulse train to form a recording mark. And the value of the format number changes according to a combination of the write strategy type and the write pre-compensation type.

Abstract: A reading devices suppresses deterioration of the recording marks caused by increasing the output laser power to compensate for a drop in the S/N ratio when reading at a high speed information recorded to a high density recording medium. To read information recorded to an optical data recording medium that is written and read using a laser beam output from a semiconductor laser, the reading method modulates a high frequency current on the drive current of the semiconductor laser to output the laser beam, and changes the light modulation rate according to the selected linear velocity used for reading. The light modulation rate is the ratio Pp/Pave between the peak power Pp and the average read power Pave of the light intensity of the high frequency modulated laser beam.

Abstract: An information recording medium, comprising N number (N is an integer fulfilling N?3) of information layers on which information is recordable, and allowing information to be recorded on each of the information layers and allowing information recorded on each of the information layers to be reproduced by being irradiated with laser light. The N number of information layers include an N?th information layer, an (N?1)th information layer, an (N?2)th information layer, . . . a second information layer and a first information layer sequentially located from a laser light incidence side. A reflectance of the N?th information layer is RN, and a reflectance of an M?th information layer (M refers to every integer fulfilling N>M?1) is RM.

Abstract: An optical recording medium that allows information to be recorded and played back properly, even when a type of recording medium in which information is recorded to grooves is used along with a type of recording medium in which information is recorded to lands, as well as a method for recording and playback with this medium. Recording track information is recorded in advance, indicating whether information is to be recorded in the grooves or the lands, whichever of the grooves and lands is best suited to the recording of information is selected on the basis of the recording track information that is read out, and the recording or playback of information is performed.

Abstract: An information recording medium according to the present invention includes three or more information recording layers. Each of the plurality of information recording layers includes a test recording area usable for adjusting a recording condition. One of the plurality of information recording layers includes a reproduction-only management data area in which management data usable for managing the information recording medium is pre-recorded. Each of the other two or more information recording layers among the plurality of information recording layers includes a test recording area at a radial position partially overlapping the radial position of the management data area.

Abstract: The present invention has an object of providing an optical information recording medium including three or more information layers, which allows information to be reproduced from all the information layers at high quality, and a method for reproducing information from such an information recording medium. The reflectance of a third information layer 43 is made higher than that of each of a second information layer 42 and a first information layer 41. Thus, the upper limit reproduction power of laser light 31 directed to the third information layer 43 can be made lower than that of the laser light 31 directed to each of the second information layer 42 and the first information layer 41. For reproduction, the reproduction power of each information layer is equal to or lower than the upper limit reproduction power, and a product of the reflectance and the reproduction power is substantially the same among the information layers. Thus, the information reproduction can be conducted at high quality.

Abstract: The present invention provides a novel physical structure for a multilayer optical information recording medium including a plurality of information recording layers, and a recording method and a recording/reproduction apparatus for such a recording medium using the same. The multilayer optical information recording medium according to the present invention includes a test recording area for performing test recording for data recording and/or reproduction conditions in at least one of an inner zone and an outer zone. The test recording area is categorized as one of at least two categories of test recording areas (OPC-A area and OPC-B area). In the OPC-B area, an upper limit value is set on a recording power for the test recording.

Abstract: A method for recording and reproducing information to/from with an optical recording medium, with which either in-groove recording or on-groove recording is selected according to a type of the recording medium, and information can be recorded and reproduced with good signal quality. In this method a laser beam is reflected by an information recording layer and is received by a photodetector that has been split into at least two parts by a split line parallel to the direction of the grooves. Further, the laser beam is reflected in a region in which a groove width is greater than a width between grooves, and the method determines whether the grooves on a side where the laser beam is incident are convex or concave based on a sum signal and a difference signal of photodetection signals outputted from the photodetector.

Abstract: It is an object to provide an optical information recording medium for land/groove recording, capable of recording at a plurality of linear speeds, wherein deterioration of jitter of the reproduction signal is prevented in recording and reproduction at low linear speeds. To this end, there is provided an optical information recording medium having a land/groove structure and being capable of recording at a plurality of linear speeds, wherein the ratio of the maximum recordable linear speed to the minimum recordable linear speed has a value of 2 to 3, and the ratio of the amount of light reflected from a groove in an unrecorded state to the amount of light reflected from a land in an unrecorded state has a value of at least 1.08 and no more than 1.19.

Abstract: A plurality of types of recording pulse control rules for which the recording pulse waveform is determined according to the information signals to be recorded are stored in advance in an optical disk. When recording to the optical disk, information is recorded using a recording pulse where, due to the focused laser beam, the temperature in the recording layer cools more rapidly at a second information recording layer closer to the side where light is incident than at a first information recording layer farther away from the side where light is incident.

Abstract: An optical information recording medium includes a plurality of recording layers, a reflectance of at least one of the plurality of the recording layers in a non-initialized state with respect to a light beam for initialization being smaller than a reflectance of the same in an initialized state with respect to the light beam for initialization. The recording layers are initialized by irradiating, among the plurality of recording layers, the recording layer positioned farther from a light beam irradiation side with the light beam prior to irradiating the recording layer positioned closer to the light beam irradiation side, so that the initialized recording layers have no initialization irregularities.

Abstract: A recording and reproducing method is provided in which information can be recorded and reproduced correctly using a simple circuit structure, even with a high transfer rate, and a test record can be performed efficiently in a short time. A laser driving circuit 6 makes power levels of a front end pulse and a rear end pulse different from a power level of a middle pulse, and a record signal edge correction circuit 5 corrects an edge position of a recording pulse.

Abstract: The present invention provides a method for recording and reproducing with an optical recording medium, with which either in-groove recording or on-groove recording is selected according to the type of recording medium, and information can be recorded and reproduced with good signal quality. To this end, a laser beam reflected by an information recording layer is received by a photodetector that has been split into at least two parts by a split line parallel to the direction of the grooves, in a region in which the groove width is greater than the width between grooves, and it is determined whether the grooves on the side where the laser beam is incident are convex or concave on the basis of a sum signal and difference signal of the photodetection signals outputted from the split photodetector.

Abstract: A plurality of types of recording pulse control rules for which the recording pulse waveform is determined according to the information signals to be recorded are stored in advance in an optical disk. When recording to the optical disk, information is recorded using a recording pulse where, due to the focused laser beam, the temperature in the recording layer cools more rapidly at a second information recording layer closer to the side where light is incident than at a first information recording layer farther away from the side where light is incident.

Abstract: A plurality of types of recording pulse control rules for which the recording pulse waveform is determined according to the information signals to be recorded are stored in advance in an optical disk. When recording to the optical disk, information is recorded using a recording pulse where, due to the focused laser beam, the temperature in the recording layer cools more rapidly at a second information recording layer closer to the side where light is incident than at a first information recording layer farther away from the side where light is incident.

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 aberations have respectivley 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.

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.

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.

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.

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.