Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Rohm Co., Ltd.

Yasuhiro Gotoh

Naoyasu Miyagawa

Noboru Yamada

Isao Satoh

Seiji Nishiwaki

Sadao Mizuno

Tetsuya Akiyama

Yoshihisa Fukushima

Yoshiaki Komma

Michiyoshi Nagashima

Motoyoshi Murakami

Hiromi Nakase

Shigeyoshi Hayashi

Koichi Yamada

Kuniichi Ozawa

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

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 disc 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 thickness

A memory cell having a configuration completely different from that of a memory cell of a conventional memory and having various excellent characteristics, and also a method for manufacturing the same, are provided. A memory having various excellent characteristics is provided as well by use of the memory cell. Furthermore, a method for recording/reading information in/from the memory is provided. The memory cell includes a memory medium for holding information, a controlling part for recording information in the memory medium, and a detecting element for reading information from the memory medium, where the detecting element is provided independently of the memory medium. More specifically, for example, the memory medium is a magnetic device, the controlling part includes a first magnetic field generating part for applying a magnetic field to the magnetic device so as to change a magnetization state of the magnetic device, and the detecting element is arranged in the vicinity of the magnetic device and has a magnetoelectric converting part whose electric characteristics vary in accordance with the magnetization state of the magnetic device.

Memory cell, memory using the memory cell, memory cell manufacturing method, and memory recording/reading method

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. 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 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.

In an foreign body detection apparatus, an optical signal detection unit irradiates a light spot onto a surface of an object to be inspected while scanning the surface by employing the light spot in a predetermined direction, and receives a reflected beam from the surface of the inspected object to generate a photodetection signal corresponding to the light intensity of the reflected beam. A foreign body detection unit generates a foreign body detection signal appearing with respect to a leader and a trailer in the scanning direction of a foreign body adhering to the inspected object from the photodetection signal. The foreign body detection signal is obtained, for example, as a difference signal between the photodetection signal and a delayed photodetection signal with a predetermined delay time. A foreign body discrimination unit generates a foreign body discriminating signal indicating a region in which the foreign body is present from the foreign body detection signal.

Method and apparatus for detecting foreign body on object surface, and optical disk apparatus

An apparatus for determining an existence range of a foreign substance which is present on a surface of an object, includes: an optical system including a light source for emitting a light beam on to the surface of the object; a movement section for relatively moving the object with respect to the light beam; a light detection section for detecting a light quantity of the light beam reflected by the surface of the object to generate a light detection signal which indicates the light quantity; a difference signal generation section for generating a difference signal; a perimeter signal generation section for comparing the difference signal with a reference value to generate a perimeter signal; and a foreign substance determination section for determining an existence range of the foreign substance using the perimeter signal.

Apparatus and method for determining existence range of foreign substance

An optical information recording medium according to the present invention includes at least one groove track and at least one land track allowing information to be recorded on or reproduced from the groove track and the land track, the groove track and the land track adjoining each other. The optical information recording medium further includes: an identification signal region including a pre-pit array, the pre-pit array indicating identification information concerning the groove track and the land track; and a servo control region disposed ahead of the identification signal region along the groove track and the land track, the servo control region including wobble pits positioned so as to shift to opposite sides of a center line of either the groove track or the land track.

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Kadoma, Japan

Yasuhiro Gotoh