Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Lsi Logic Corporation

Naoyasu Miyagawa

Yasuhiro Gotoh

Kenichi Nishiuchi

Atsushi Nakamura

Kenji Narumi

Eiji Ohno

Nobuo Akahira

Tetsuya Akiyama

Takashi Ishida

Mamoru Shoji

Shigeru Furumiya

Takashi Nishihara

Motoshi Ito

Yasumori Hino

Kiyotaka Ito

Tomoyasu Takaoka

Yoshiaki Komma

Noboru Yamada

Shinya Abe

Kenji Koishi

Junichi Minamino

Shunji Ohara

Rie Kojima

Shinichi Kadowaki

Hideo Kusada

Yuji Hisakado

Yoshitaka Sakaue

Tomiharu Hosaka

Yoshito Aoki

Kazuhisa Ide

Masud Mansuripur

Katsuyuki Takahashi

When the power of the write pulse is taken as the peak power and the power of the bottom pulse is taken as the bottom power, the power setting device () sets the power of each pulse in the recording pulse train such that the peak power PwN of the Nth information layer which is closest to the light entry surface of the optical recording medium (), the bottom power PbN of the Nth information layer, the peak power PwM of the Mth information layer (where M is an integer such that N&#x3e;M&#x2267;1), and the bottom power PbM of the Mth information layer satisfy the following formula:

Optical information recording device, optical information recording method and optical information recording medium

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.

Optical information recording medium, information recording apparatus, information reproducing apparatus, information recording method, information reproducing method and method for producing optical information recording medium

There is provided an optical recording method for directing a recording pulse train to an optical disc medium to form marks thereon and for recording information as information about the edge positions of said marks and the spaces between marks, the recording pulse train having been created by modulating laser light into plural power levels. The method includes: coding to-be-recorded data into coded data consisting of the combination of marks and spaces; classifying said marks within said coded data on the basis of the mark length and the preceding or succeeding space lengths of the marks; shifting the position of the second pulse edge counted from the end portion of the recording pulse train for forming said marks, depending on the result of said classification, to adjust said recording pulse train; and directing said recording pulse train to the optical disc medium to form said marks thereon.

Method and device for optical recording onto optical disc medium

An information recording medium, comprising N number (N is an integer fulfilling N&#x2267;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&#x2212;1)th information layer, an (N&#x2212;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 R, and a reflectance of an M'th information layer (M refers to every integer fulfilling N&#x3e;M&#x2267;1) is R. The laser light used to irradiate the N'th information layer for reproducing information recorded on the N'th information layer has an upper limit reproduction power Pr, and the laser light used to irradiate the M'th information layer for reproducing information recorded on the M'th information layer has an upper limit reproduction power Pr. The following expressions (1) and (2) are concurrently fulfilled:R&#x3e;R&#x2003;&#x2003;(1)Pr&#x3c;Pr&#x2003;&#x2003;(2).

Information recording medium, recording apparatus, reproducing apparatus and reproducing method

The present invention provides a measure for getting read/write control information stored within a space of a predetermined size in a format that ensures compatibility with media of a lower order or an older generation even if the size of the read/write control information increases significantly as the storage densities of information storage media rise in the near future. On an information storage medium, a data sequence is writable as a combination of marks and spaces. The medium has at least one information storage layer, which has an information storage area to store information and a control information area for use to perform a read/write operation on the at least one information storage layer. The control information area stores at least one set of control information, which includes a first kind of write pulse information including information to be used as a reference value and a second kind of write pulse information including information to be used as an offset value. The size of the offset value is at least a half as large as that of the reference value.

Information recording medium, method for recording information on information recording medium, method for reproducing information from information recording medium and method for producing information recording medium

An optical disk includes a first information recording layer, and second to N-th information recording layers (with N being an integer of two or greater) that are arranged further toward the side from which laser light is irradiated than the first information recording layer and which are arranged in order from the side near the first information recording layer. The first information recording layer includes a read-only control data region, a first recording learning region for learning recording parameters to record data, and a first user data recording region for recording user data. When taking at least one of the second to N-th information recording layers as an i-th information recording layer (with i being an integer satisfying 2&#x2266;i&#x2266;N), that i-th information recording layer includes an i-th recording learning region for learning recording parameters to record data in the i-th information recording layer, and an i-th user data recording region for recording user data. The first recording learning region and the i-th recording learning region are arranged at different radial positions, and the i-th recording learning region is arranged within a region of radial positions at which the control data region is provided.

Optical disk, method for manufacturing the same, and method for recording and method for reproducing data using optical disk

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.

Reading device and reading method for an optical data recording medium

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. Instead of an optical head having objective lenses, an optical head having a waveguide and a plurality of converging grating couplers whose aberrations have respectively been corrected for a plurality of disc substrates of different thicknesses is provided to achieve the same object.An optical recording/reproducing apparatus for recording, reproducing or erasing an information signal onto/from an optical disc having at least a transparent substrate and an information layer by converging a light flux on the information layer through the transparent substrate. The apparatus includes optical converging devices, with different numerical apertures, focal distances or working distances, such as objective lenses or grating lenses, for performing aberration correction over a plurality of transparent substrates of different thicknesses of optical discs and a device for discriminating the type of optical disc based on the thicknesses of the transparent substrates. One of the optical converging devices that generates the least aberration is used according to a result of the discrimination of the thickness of the optical disk loaded in the apparatus to cause the information signal to be suitably recorded, reproduced or erased onto/from the optical discs having the different substrate thicknesses.

Optical recording/reproducing apparatus for optical disks with various disk substrate thicknesses

Because conditions for recording identification data of a medium vary in accordance with the structure of different media, such as a single-layer or a multiple-layer structure, stable data recording has been a difficult task. To solve this problem, an incident side of the laser beam for recording identification data on a single-layer optical diskand a double-layer optical diskis the opposite side of a substrateupon which user data is recorded. From this structure, even in a double-layer optical diskthe recording is not affected by the recording layer of a second layerand the like. Therefore, in the double-layer optical diskidentification data of the medium can be recorded under the same conditions as the single-layer optical disk

Method of recording information, equipment thereof and information recording medium

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.

Optical recording medium, method for manufacturing the same, recording/playback method, and recording/playback apparatus

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.

Method for recording to and reproducing from an optical recording medium, optical recording medium, and recording and reproduction apparatus for the same

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.

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Kawanishi, Japan

Naoyasu Miyagawa