Abstract: A scanning laser projection system includes a virtual protective housing circuit to automatically reduce accessible emissions of visible laser light by decimating areas of a projected image to reduce optical power exposure levels for safety, comfort, aesthetic, or system classification purposes. IR laser light pulses are scanned in a field of view, and a percentage of visible laser light pulses are blanked based on attributes of reflections of the IR laser light pulses.

Abstract: A lighting device comprising a pump light source and two or more phosphor wheels arranged one directly behind another. As a result, firstly, the heat loss can be dissipated via the two phosphor wheels. Secondly, only a single common collecting optical unit is required for collecting the conversion light emitted by the first phosphor wheel and the second phosphor wheel.

Abstract: A projection display apparatus includes: a display element that displays an image; a lamp that illuminates the display element to cause the display element to emit an image light; a variable light intensity element that allows the light emitted from the lamp to pass therethrough, the intensity of light passing through the variable light intensity element being variable; and a light intensity controller that determines whether the display element is at an image mute state in which a full-black image is displayed, or at a normal lighting state other than the image mute state, and when the display element is at the image mute state, reduces the amount of power supplied to the lamp to a level that is lower than that of the normal lighting state to decrease the intensity of light emitted from the lamp, and also decreases the intensity of light that passes through the variable light intensity element.

Abstract: Then, in order to achieve the above-described object, in the optical disk of the present invention, while micro-hologram layers 7 and 8 made of plural layers are provided in an inner portion of a plate body 2 along a thickness direction of the plate body 2, dimensions of micro-holograms 4 along the thickness direction of the plate body 2, which configure the micro-hologram layer 7 formed on the side of one surface of the plate body 2 within the micro-hologram layers 7 and 8 constructed of the plural layers, are made smaller than dimensions of micro-holograms 3 along the thickness direction of the plate body 2, which configure a micro-hologram layer 8 formed on the side of an inner layer of the plate body 2.

Abstract: An optical information recording and reproducing apparatus relating to the invention employs a two-beam interference method. In the optical information recording and reproducing apparatus, a moving device moves an information recording medium between a recording and reproducing position and a retracting position, and a mirror moves together with the information recording medium. When the information recording medium moves to the recording and reproducing position, the mirror moves to a position which is displaced from the at least one of the reference beam and the information beam. When the information recording medium moves to the retracting position, the mirror moves to a position where the mirror can reflect the at least one of the reference beam and the information beam toward a detector for detecting a deviation of the at least one of the reference beam and the information beam.

Abstract: A disk device includes a main control unit controlling the operation of a controlled object on the basis of an error signal calculated from a target signal of the controlled object and an observation signal of the controlled object, a repetitive control unit sampling the error signal with a sampling clock pulse to obtain a repetitive signal component generated in synchronization with rotation of the disk medium from the sampled error signal, a sampling clock generation unit generating the sampling clock pulse and resetting a timing at which the sampling clock pulse is generated in accordance with a rotation detecting pulse and a sampling clock limit unit limiting generation of the sampling clock pulse at a timing immediately before generation of the rotation detecting pulse.

Abstract: A signal drive apparatus includes a first buffer circuit where a signal converted into an electric signal from a first light signal is amplified; a second buffer circuit where a signal converted into an electric signal from a second light signal is amplified; a control circuit causing one of the first and second buffer circuits to be in an operating state and causing an output stage of the other buffer circuit to be in an idle state of a high impedance, so as to output a changeover control signal which picks up either the first or the second light signal; and a voltage changeover circuit causing any one of the output stages of the first and the second buffer circuits to be in the idle state and supplying a transistor constituting the output stage with a bias voltage equal to or less than a withstand voltage of the transistor.

Abstract: An optical disk drive according to the present invention has the ability to read data from multiple types of optical disks, each of which includes at least one information storage layer. The drive includes: a driving mechanism 120, which is loaded with a selected one of the optical disks of the multiple types and which rotates the optical disk 102; an optical pickup 30 for irradiating the optical disk 102, which has been loaded into the driving mechanism 120, with a converged light beam, thereby generating an electrical signal based on light that has been reflected from the optical disk 102; and a control section (ODC 50) for controlling operations of the driving mechanism 120 and the optical pickup 30. The control section 50 includes a right/wrong side determining section for determining, by reference to the electrical signal generated by the optical pickup 30, whether or not the optical disk 102 has been loaded into the driving mechanism 120 with the other surface opposed to the optical pickup 30.

Abstract: A resin objective lens having a numerical aperture NA?0.75. The objective lens satisfies a condition: 0?|SC|MAX/f<0.002 where f denotes a focal length at a wavelength ? and |SC|MAX denotes a maximum absolute value of an offence against a sine condition in a range larger than or equal to 0% and smaller than 90% of an effective beam radius with respect to an optical axis. The objective lens is configured such that the offence against the sine condition at a 100% point of the effective beam radius is smaller than that defined at a 90% point. At least a light source side surface of the objective lens is formed to be an aspherical surface, and the objective lens satisfies a condition: 1.40<(n?1)·(SAG1)?MAX·/NA2<1.95 where (SAG1)?MAX represents a maximum gradient of the light source side surface within an effective beam diameter.

Abstract: A data recording device comprises a block division unit dividing a sequence of user data blocks into first blocks and second blocks, a plurality of multi-level data generating units generating multi-level data blocks from the first blocks and the second block, a group data storage unit storing first and second groups of code data corresponding to one user data block, a plurality of averaging units each calculating an average of DC levels based on the multi-level data of one of the blocks, a level comparison unit comparing each of the DC level averages with a predetermined value; a revision data generating unit generating a revision data using a result of the comparison, a data selection unit selecting one of the first and second groups of code data, and an output storage unit storing the first blocks, the second blocks generated using the selected code data, and the revision data.

Abstract: This invention relates to an optical scanning device for scanning an optical record carrier and detecting a tilt characteristic of the optical record carrier during scanning. The device includes a redirecting structure (26) arranged on an objective lens (10) to redirect a part of a radiation beam, when travelling towards the record carrier, differently to a main part of the radiation beam. The redirected beam part follows a path which is different to that of a path followed by the main beam part, towards a position sensitive detector in a detection system (16).

Abstract: There is provided an objective lens which has positive refractive power and has a single lens element having an incident surface from which the collimated beam enters and an exit surface from which the collimated beam emerges. Further, the incident surface and the exit surface are configured to be rotationally symmetrical aspherical surfaces. At least within an effective diameter of the single lens element, the incident surface and the exit surface are symmetrical with respect to a plane perpendicular to an optical axis of the single lens element and have the same shape.

Abstract: A method for recording information on a recording medium utilizing an interference pattern by interference between an information light modulated spatially with digital pattern information displayed on a spatial light modulator having multiple pixels and a reference light for recording. In order to provide a novel recording method capable of enhancing the recording density and the transfer rate furthermore, digital information to be recorded is represented by match/mismatch of the attributes of adjacent pixels in the spatial light modulator to produce digital pattern information.

Abstract: An object of the present invention is to attain stable tracking servo performance by suppressing an offset caused by a shift of an object lens or a tilt of a disk, despite the one-beam method which does not cause reduction in light quantity of the main beam. A diffraction grating is provided between a hologram and a light receiving section, and a diffraction efficiency of the diffraction grating is varied in a grating longitudinal direction. For example, if an incident light beam on the diffraction grating is shifted in the grating longitudinal direction, the quantity of received light in each light receiving section varies to cause offset. By performing tracking servo so as to cancel the change, it is possible to correct the offset, thereby attaining stable tracking servo performance.

Abstract: An optical disk system includes at least one photo detector connected with a variable gain amplifier, a slicer, and a generator which is in the feedback path between the slicer and amplifier. A differential time delay detector provides the output of the optical disk system. The generator is configured for controlling the amplifier non-linearly so that time constants of the control loop of the amplifier which depend upon the level of the input signals are compensated and the timing behavior of the control loop of the amplifier has a more continuous character. A capacitor forms part of an integrator for making the mean value of the output voltage signal of the slicer equal to zero.

Abstract: A data demodulation process rate is varied according to a reproduction state, thereby reducing power consumption while maintaining a reading performance in a favorable state. A channel rate process data demodulation device performs a data demodulation process by employing channel bit frequency. Further, a half rate process data demodulation device performs a data demodulation process by employing frequency half as high as the channel bit frequency. These devices demodulate digital data from an optical recording medium. A process rate switching device switches a process rate at data demodulation, whereby demodulation is performed by switching between the data demodulation devices according to a quality of a reproduction signal, so as to reproduce the digital data recorded on the optical recording medium.

Abstract: A tracking controller includes a tracking error detecting section and a tracking control section. The tracking error detecting section generates and outputs a tracking error signal that represents how much the focal point of a light beam has shifted from a target track on a storage medium. The tracking control section generates a drive signal in response to the tracking error signal so as to move the light beam such that the focal point of the light beam is located right on the target track. The gain of at least one of the tracking error signal and the drive signal is switched depending on whether or not the focal point of the light beam is located on a recorded area of the storage medium on which data has already been written.

Abstract: A device for reading from and/or writing to optical recording media 10, on which information is present in the form of pits, with a linearly polarized light beam 2. A device for reading from and/or writing to optical recording media 10 which ensures correct reproduction of the stored data even when the recording medium influences the polarization of the light beam 2.

Abstract: An optical pickup includes: a first projector for projecting a first light beam of a first wavelength so as to record and reproduce information with respect to an optical disk having a first light transmissive layer; a second projector for projecting a second light beam of a second wavelength longer than the first wavelength so as to record and reproduce information with respect to an optical disk having a second light transmissive layer; an objective lens common to the first and second light beams; and a diffraction optical element made of a lens with a diffraction grating and a refracting face and disposed in an optical path between the first and second projectors and the objective lens. The diffraction optical element is set to satisfy a predetermined equation.

Abstract: An optical signal converter and a method or controlling an amplification gain according to a rotating speed of an optical disc. An optical signal detector detects an optical signal reflected from an optical disc in a reproduction mode and converts the detected optical signal into an electrical signal. A gain control signal generator generates a gain control signal when a voltage level of a driving signal used to drive the optical disc exceeds a maximum output voltage of the optical signal converter. A gain switcher selects an amplification gain of the optical signal converter in response to the gain control signal and an external control signal. A signal amplifier amplifies a signal output from the optical signal detector in response to an output signal of the gain switcher.