Abstract: A security system of the present invention using an optical information recording medium allowing concurrent reading out of ROM-RAM information, is able to receive data from the optical information recording medium having an identification symbol recording region recording an identification symbol identifying the medium, a ROM region recording plain text data, and a magneto-optical recording film formed in a region corresponding to the ROM region, the magneto-optical recording film recording encrypted data of the plain text data, the security system being configured such that the recording medium recording a decryption program for decrypting the encrypted data is usable, the security system comprising a reception unit for receiving the encrypted data in response to a data transmission request that conforms to the identification symbol identifying the optical information recording medium; a recording unit for recording in the recording medium the encrypted data received from the reception unit; and a decryptio

Abstract: An optical recording medium is provided with a substrate having a land and a groove alternately arranged in a predetermined direction, a data recording region provided on the land and the groove, and an identification mark recording region recorded with a data block identification mark. The identification mark recording region is provided on only one of the land and the groove.

Abstract: An optical recording medium is provided with a substrate having a land and a groove alternately arranged in a predetermined direction, a data recording region provided on the land and the groove, and an identification mark recording region-recorded with a data block identification mark. The identification mark recording region is provided on only one of the land and the groove.

Abstract: A storage apparatus, capable of record or reproduce of an optical information recording medium in which ROM information is recorded with phase pits and RAM information is recorded on top of a recording region of the phase pits, has a main controller that, when the output of the recording information detection system—a system for detecting reflected light of a laser beam from the optical information recording medium and generating signals corresponding to ROM and RAM information—simultaneously contains ROM and RAM signals corresponding to ROM and RAM information, performs negative feedback control of a semiconductor laser emission using ROM signal in the output of the recording information detection system and performs control so as to obtain read-out and played-back ROM signal from the output of an optical intensity detection system for detecting the intensity of the laser light.

Abstract: An optical information recording medium having a plurality of grooves and a plurality of lands alternately formed, where each groove and each land function as recording tracks. The medium includes a first header region having a plurality of first phase pits respectively formed on extensions of the plurality of lands, and a second header region having a plurality of second phase pits respectively formed on extensions of the plurality of grooves. Each groove has an optical depth of about 3&lgr;/8, where &lgr; is the wavelength of a light beam to be used. Each first phase pit has an optical depth that is smaller than that of each groove. Each second phase pit has an optical depth that is substantially equal to that of each groove. The first header region and the second header region are shifted from each other along the extension of each groove.

Abstract: A device for reading from and/or writing to optical recording media, the device comprising a light source for producing a scanning beam, a photodetector for detecting the scanning beam reflected by the recording medium and a semi-transparent mirror arranged in the beam path for directing the scanning beam onto the recording medium and the reflected scanning beam onto the photodetector. An object of the invention is to improve a device of this type, in particular with regard to reducing the production costs. This object is achieved by the semi-transparent mirror being a plane-parallel plate with a layered structure, and a partially reflective layer being arranged between two small carrier plates.

Abstract: An optical information storage unit for reproducing information recorded on lands and grooves of a magneto-optical recording medium by means of a reflected light obtained from a luminous flux which has been emitted from a light source, irradiated onto the recording medium and reflected from the recording medium. The optical information storage unit includes a first wave plate on which the reflected light from the magneto-optical recording medium is incident; a diffraction grating on which the light having been transmitted through the first wave plate is incident; a second wave plate on which the light having been transmitted through the diffraction grating is incident; and a polarization detecting unit on which the light having been transmitted through the second wave plate is incident.

Abstract: An optical storage unit which uses a light beam to record information on and/or reproduce information from a recording medium. The recording medium is provided with at least one land and at least one groove, and information is recorded in plural sectors in each of the land(s) and groove(s). The optical storage unit includes an optical phase adjuster for adjusting a phase of a polarization component of the light beam reflected from the recording medium based on a track type determination of a target address. An optical pickup is provided for reproducing information recorded on the recording medium using the phase-adjusted polarization component of the light beam.

Abstract: An optical information recording medium having a plurality of grooves and a plurality of lands alternately formed. Each groove and each land function as recording tracks. The medium includes a first header region having a plurality of first phase pits respectively formed on extensions of the plurality of lands, and a second header region having a plurality of second phase pits respectively formed on extensions of the plurality of grooves. Each groove has an optical depth of about 3&lgr;/8 where &lgr; is the wavelength of a light beam to be used. Each first phase pit has an optical depth smaller than that of each groove. Each second phase pit has an optical depth substantially equal to that of each groove. The first header region and the second header region are shifted from each other along the extension of each groove.

Abstract: Disclosed is an optical storage device for reading information from an optical storage medium by an optical head. The optical storage device comprises an optical head including a track actuator for scanning on the skew across tracks on the optical storage medium by the laser beam, and a divided-by-4 light receiving unit for receiving the laser beam from the optical storage medium, a moving motor for moving the optical head, a first signal processing unit for calculating a track error signal on the basis of an output of the divided-by-4 light receiving unit, a second signal processing unit for calculating a shift signal of the objective lens from the output of the divided-by-4 light receiving unit, and a control unit for controlling the track actuator or the moving motor by the track error signal, and controlling the track actuator or the moving motor so that the laser beam passing through the objective lens is located at the center of the objective lens.

Abstract: The present invention relates to a device for reading from and/or writing to optical recording media (6), which has a light source (1) for producing a scanning beam (2), a photodetector (7) for detecting the scanning beam (2) reflected by the recording medium (6) and a semi-transparent mirror (3) arranged in the beam path for directing the scanning beam (2) onto the recording medium (6) and the reflected scanning beam (2) onto the photodetector (7).

Abstract: An optical information recording medium having a plurality of grooves and a plurality of lands alternately formed, where each groove and each land function as recording tracks. The medium includes a first header region having a plurality of first phase pits respectively formed on extensions of the plurality of lands, and a second header region having a plurality of second phase pits respectively formed on extensions of the plurality of grooves. Each groove has an optical depth of about 3 &lgr;/8, where &lgr; is the wavelength of a light beam to be used. Each first phase pit has an optical depth that is smaller than that of each groove. Each second phase pit has an optical depth that is substantially equal to that of each groove. The first header region and the second header region are shifted from each other along the extension of each groove.

Abstract: An optical information storage apparatus is constructed to include a light source, a polarization beam splitter reflecting a light beam emitted from the light source and irradiating a reflected light beam on a recording surface of a recording medium, a first part for eliminating a coma aberration which is generated due to a light beam which is reflected by the recording surface and passes through the polarization beam splitter, a second part for eliminating an astigmatism which is generated by the polarization beam splitter and the first part, and a third part for generating an astigmatism.

Abstract: An optical information storage unit irradiates a light on a recording medium having a recording surface provided with a land and a groove and detects a reproduced signal from a light reflected from the recording medium. The optical information storage unit is provided with a phase compensation mechanism, provided in an optical path through which the light irradiated on the recording medium and a reflected light from the recording medium passes, for applying with respect to the reflected light a first phase compensation quantity required to detect a signal from the land and a second phase compensation quantity required to detect a signal from the groove.

Abstract: An optical information storage unit records information on and/or reproduces information from both a land and a groove of an optical recording medium which have approximately the same width. The optical information storage unit is provided with a first optical system, including a first light source and a first phase compensation means, detecting light from the land of the optical recording medium, and a second optical system, including a second light source and a second phase compensation means, detecting light from the groove of the optical recording medium. The first and second phase compensation means have mutually different phase compensation quantities.

Abstract: An optical information storage unit for reproducing information recorded on a magneto-optic recording medium having a land and a groove as recording tracks, is provided with at least one of first and second systems, where the first system includes a 1/2 wave plate which is arranged so that a crystal optical axis of the 1/2 wave plate and an electrical vector of a light beam emitted from a light source forms approximately 45 degrees, where the 1/2 wave plate being removable from a position of the light beam, and the second system is arranged with the 1/2 wave plate so that the crystal optical axis of the 1/2 wave plate and the electrical vector of the light beam emitted from the light source forms approximately 45 degrees, where the 1/2 wave plate is movable so that another 1/2 wave plate can move to the position of the light beam so that a crystal optical axis of the other 1/2 wave plate is parallel to or perpendicular to the electrical vector.

Abstract: An optical information storage unit is provided with a light source, a polarization beam splitter reflecting and irradiating a bundle of rays emitted from the light source onto a recording surface of a recording medium, and an optical element receiving a convergent light reflected by the recording surface and passed through the polarization beam splitter, and having an infinite focal distance with a convergent point of the convergent light that is variable.

Abstract: An optical recording medium is made up of an optically transparent substrate having a groove and a land which have approximately the same width and are formed spirally or concentrically, where the groove has an optical depth described by (1/8+(1/2)n).lambda., n is 0 or a positive integer and .lambda. is a wavelength of a laser. At least one of two walls defining the groove is zigzag shaped and the groove is capable of having digital information recorded thereon.

Abstract: An optical information storage apparatus is constructed to include a light source, a polarization beam splitter reflecting light emitted from the light source and irradiating a reflected light on a recording surface of a recording medium, and an optical element, made of an optically transparent material, having an input surface to which light reflected by the recording surface and transmitted through the polarization beam splitter is input, and an output surface from which light is output. The optical element is inclined within a plane which is perpendicular to a light incident surface of the polarization beam splitter and includes an optical axis along which light travels. In addition, the input surface and the output surface of the optical element are parallel to each other.

Abstract: An optical information storage unit for irradiating a light on a recording medium which has a recording surface with a land and a groove, and detecting a reproduced signal from a reflected light received from the recording medium, is constructed to include a first optical element separating the reflected light received from the recording medium into at least three bundles of rays, a second optical element compensating phases of the bundles of rays separated by the first optical element, and a third optical element detecting polarization states of the bundles of rays separated by the first optical element. An amount of phase compensation made by the second optical element is such that an absolute value of a difference between an amount of phase compensation required to reproduce a signal from the land and an amount of phase compensation required to reproduce a signal from the groove is greater than or equal to 60.degree. but less than or equal to 180.degree..