Abstract: An optical pickup having a simple structure and that is capable of recording using a plurality of wavelengths is provided, comprising a primary laser light source for emitting a primary laser light having a first wavelength and that is of sufficient power for recording, an integrated device further comprising a secondary laser light source for emitting a secondary laser light having a second wavelength that is longer than the first wavelength and that is of sufficient power for recording as well as light receiving elements for receiving the light of the primary and secondary laser lights, and a polarized light beam splitter having polarization selectivity in respect of the secondary laser light.

Abstract: In a method for writing data to an information recording medium having a plurality of recording layers, user data is written across between a plurality of the recording layers, and data other than the user data is written in a predetermined zone of the recording layer. Thereby, since the user data is written continuously upon switching of a recording layer without data other than the user data being written, it is possible to avoid interruption of writing of the user data to the recording layers.

Abstract: Providing an objective lens with a large numerical aperture (NA), the present invention records or plays conventional optical disks such as CDs and DVDs at high light usage efficiency, using an optical head capable of recording or reproducing high-density optical disks. A diffraction optical element (8) is disposed in a light path of a first light beam of a first wavelength ?1 (400 nm to 415 nm) and a second light beam of a second wavelength ?2 (650 nm to 680 nm). And, the present invention principally emits 5th order diffracted light with respect to the first light beam, and principally emits 3rd order diffracted light with respect to the second light beam, from the diffraction optical element (8). Thus, a high diffraction efficiency of substantially 100% can be obtained with respect to both wavelengths.

Abstract: A method of adjusting a condition for at least one of a recording operation and a reproducing operation includes the following steps. At least first and second asymmetry values is found. The first asymmetry value is defined based on a first signal combination selected from at least three signals different in cycle from each other. The second asymmetry value is defined based on a second signal combination selected from the at least three signals. The second signal combination is different from the first signal combination. The condition is set with reference to the at least first and second asymmetry values.

Abstract: An apparatus for detecting and correcting a relative address on an optical storage medium, includes a relative address detector which reads relative addresses recorded on the optical storage medium, a relative address continuity detector which checks whether the number of continuances between the relative addresses output from the relative address detector is at least a predetermined number N, and a relative address corrector which forcibly corrects a current relative address that is not consecutive to a previous relative address and outputs the corrected relative address, after the relative address continuity detector determines that the number of continuances between the relative addresses is at least the predetermined number N.

Abstract: It is an object of the present invention to provide an apparatus for discriminating an optical recording medium which can reliably discriminate the kind of an optical recording medium even in the case where the optical recording medium to be discriminated is warped and formed with periodical undulation in the circumferential direction thereof.

Abstract: While supporting an optical disc having a recording density that is higher than conventional optical discs by shortening the wavelength of the emitted light and increasing the numerical aperture (NA) of an objective lens, a reduction in the size of an optical pickup apparatus relative to the size of a disc cartridge that houses the optical disc is achieved. The present invention includes a fixed optical system having a built-in light source, and a movable optical system having an objective lens. A parallel light beam that enters the movable optical system from the fixed optical system enters the movable optical system via a light path that is parallel to the direction in which the objective lens is movable and from the side on which a spindle motor is provided.

Abstract: A photodetector, includes: a semiconductor chip that converts received light to an electric signal; and a resin body that encapsulates the semiconductor chip. The photodetector further includes a protective unit, and at least a light transmission area, through which the light passes, in a surface of the resin body on an incident side of the light is covered by the protective unit. Covering the light transmission area with the protective unit that is less in reactivity with light than the resin body can suppress deformation of the resin body due to light, thus suppressing deterioration of the optical characteristics of the photodetector.

Abstract: An optical recording/reproducing method and an optical recording medium capable of performing excellent optical recording with a simple structure in a recording layer made of environmentally friendly materials. The optical recording medium has a recording layer on a substrate. The recording layer has a pair of dielectric layers of which states are altered by a laser beam that is an energy beam of which intensity is modulated according to information to be recorded. This recording layer also has a assisting material layer sandwiched by these dielectric layers. The assisting material layer includes an element selected from Sn, Ti, Si, Bi, Ge, and C as a principle component, while the dielectric material as a base material for the dielectric layers is any one of ZnS, SiO2, AlN, and Ta2O5.

Abstract: A recording medium on which at least one piece of data that has been encoded with a first error correction code and data that can be decoded with the first error correction code and that can be decoded with a second error correction code that is different from the first error correction code.

Abstract: An information recording apparatus is capable of recording data and management information of an information recording medium in a plurality of data recording formats. Typically, a DVD+RW is considered to be a DVD+R disk, when data and management information of the DVD+R are recorded on the DVD+RW disk in the data recording format for the DVD+R disk, such as the sequential writing method and the multi-session writing method.

Abstract: The invention concerns a recording medium for optically readable data of the multilayer type, a method for making same and an optical system for reproducing said data for reading the medium. The medium (Sb) comprises a stack of layers (C1 to CN) whereof the interfaces constitute planes (P1 to PN) bearing slightly phase-shifting information elements. Said planes generate a relatively significant disturbance of the transmitted beam while diffracting only a very small part of the light passing through them. The reading beam (FI) is focused on the bearing plane and reading is performed by transmission. The disturbances caused by the neighboring defocused layers are eliminated by far field detection of only the low spatial frequencies in the transmitted beam. The invention is particularly useful for very high capacity data optical storage.

Abstract: An optical pickup device includes a frame F in which an integrated optical unit equipped with a semiconductor laser diode is incorporated and a flexible substrate F having a short-circuit wiring pathway connecting two connectors and a driving circuit. The short-circuit wiring pathway is connected to the integrated optical unit and the driving circuit at a minimum distance through the connector in such a manner that the flexible substrate F is incorporated so as to be wound along the frame F. Consequently, recording processing and the like can be stably performed.

Abstract: A disk recording-playback device including a laser drive circuit for feeding a drive signal to an optical head and adjusting the power of a laser beam irradiated by the optical head, an error correcting circuit for detecting an error rate of a reproduced signal, and a system controller for controlling operation of the laser drive circuit for signal reproduction and signal recording based on the output of the error correcting circuit. The system controller successively sets the laser powers to at least three different values, obtains evaluation data for each laser power, approximates the relationships between the laser powers and the evaluation data to a quadratic curve, whereby an optimum laser power is derived corresponding to a vertex of the quadratic curve. Accordingly the optimum reproduction power and recording power are set, to thereby record and reproduce signals with high accuracy.

Abstract: An objective lens for use in an optical pickup apparatus has a diffractive optical surface. A first light flux having a first wavelength of ?1 is converged as a first number diffraction order diffracted-ray other than the zero-th order diffracted-ray onto an information recording plane of the first optical information recording medium having a thinner protective substrate t1 by the diffractive optical surface and a second light flux having a second wavelength of ?2 (?1<?2) is converged as a second number diffraction order diffracted-ray other than the zero-th order diffracted-ray onto the information recording plane of the second optical information recording medium having a thicker protective substrate t2 (t1<t2) by the diffractive optical surface. The second number diffraction order is different from the first number diffraction order.

Abstract: A lens support mechanism including a semiconductor laser 10 for emitting a laser beam, an optical head enclosure 3 to which the semiconductor Laser 10 is fixed and located, a collimator lens 21 disposed coaxially with the laser beam emitted from the semiconductor laser 10, a resin cylinder 22 formed in a cylindrical shape so as to fix and locate the collimator lens 21 to the inner surface thereof and a cylindrical member 23 fitted to the resin cylinder 22 on a side of the collimator lens 21 opposite to the semiconductor laser 10 and formed so as to be fixed to the optical head enclosure 3. The cylindrical member 23 has almost the same linear expansion coefficient as that of the optical head enclosure 3.

Abstract: An apparatus and method thereof detect a location of a pickup in an optical disc. A pickup reads and writes a signal from or to the optical disc. A spindle motor rotates the optical disc. A controller measures a rotational speed of the spindle motor to detect a current location of the pickup in the optical disc, wherein the pickup is determined to be located in an area of more than 90 minutes of the optical disc based on ATIP information recorded on the optical disc.

Abstract: A method for controlling the rotation speed of an optical storage device. In the first mode, a first signal is produced, and in the second mode, a second signal is produced. In one mode, a first pulse of a first voltage and a second pulse of a second voltage are sent to the motor, which causes the motor to produce a first armature current and a second armature current. In another mode, a DC signal of a third voltage is produced, which causes the motor to produce a third armature current. The armature currents are detected, and test voltages are outputted. The first and second voltages, and the first and second test voltages are used to find a motor coefficient. The third voltage, the motor coefficient, and the third test voltage are used to calculate a motor rotation speed. The calculated speed is used to control the real motor speed.

Abstract: A reproduction method for reproducing BCA data for optical discs using the defect signal. The reproduction method for reproducing BCA data includes the steps of: generating a defect signal as a BCA signal by detecting an RF signal of the BCA; generating a BCA data bit stream by sampling the BCA signal according to a sampling clock; and decoding the BCA data bit stream to generate BCA data. Because the defect signal is utilized as the BCA signal of the invention, no additional BCA signal extracting device is needed.

Abstract: The present invention provides a disk playback device comprising a laser drive circuit 15 for feeding a drive signal to an optical head 4 and adjusting the power of a laser beam irradiated by the optical head 4, an error correcting circuit 11 for detecting an error rate of a reproduced signal, and a system controller 10 for controlling operation of the laser drive circuit for signal reproduction and signal recording based on the output of the error correction circuit 11. The system controller 10 retrieves one limit value of two limit values of a reproduction power wherein the error rate is not beyond a prescribed value, and calculates an optimum reproduction power based on the one limit value retrieved. Accordingly it is possible to move to signal reproduction in a short period of time and to reproduce signals with high accuracy by setting the optimum reproduction power.