Abstract: A system and method for providing direct read after write functionality in an optical data storage device include an optical head having a first coherent light source modulated at higher power during writing of data to the optical medium and a second coherent light source operating in a continuous wave mode at lower power while the first coherent light source is writing data. Optic components combine light from the first and second light sources and focus light from the first coherent light source to a first spot of a selected track on the optical medium and focus light from the second coherent light source to a second spot on the selected track downstream from the first spot relative to movement direction of the optical medium to read and verify the data directly after writing during the write process rather than in a separate verification process.

Abstract: An objective lens for optical pickup and an optical pickup apparatus having the same are provided. The objective lens for optical pickup includes a light source side lens surface and a disc side lens surface. The light source side lens surface and the disc side lens surface each include an effective region disposed at a central region of the objective lens and a non-effective region disposed outside the effective region. An optical path changing element, disposed in the non-effective region of at least one of the light source side lens surface and the disc side lens surface, changes a path of light incident thereon.

Abstract: An element holding device of the present invention includes: a guide portion engaging with a guide shaft; a lens fixing portion on which to fix a collimator lens; an arm portion; an insertion portion having a hole portion in which to insert a guide shaft; a wire fixing portion made by protruding a side surface of the insertion portion in a ?Y direction; and a wire fixed on the wire fixing portion. A bent portion being a leading end portion of the wire is housed in a slit. Thereby, excess deformation of a contact portion is suppressed.

Abstract: According to one embodiment, an information recording and reproducing apparatus including, a focus control module, an objective lens control module, a calculation module, and a tracking control module. If, detection the recording marks line, to focus a laser light of a second wavelength to the recording layer through an objective lens and to operation a recording layer tracking control using a tracking error signal taken out from a second reflected light and a laser light of a first wavelength to a track groove through the objective lens and to operation a guide layer tracking control to control the objective lens using a tracking error signal taken out from a first reflected light.

Abstract: Aspects of the disclosure provide an apparatus. The apparatus includes a collimator configured to have a plurality of positions, and a controller configured to control the collimator to move to a predetermined position associated with a data layer of an optical storage medium to collimate a light beam. The collimated light beam is then focused onto the data layer of the optical storage medium.

Abstract: New and useful methods and systems for reading optical discs, such as multi-layer Blu-ray discs are disclosed. For example, in an embodiment a device for reading two-layered optical discs includes a laser diode capable of emitting light, a set of optics including a fixed collimator, the set of optics providing a numerical aperture (NA) of substantially less than 0.85, and a detector for detecting laser light focused on a two-layer optical disc to produce a stream of detected bits.

Abstract: An optical pick-up is provided. The optical pick-up includes a light source, a first objective lens configured to focus light emitted from the light source on a high-density optical information storage medium, a photo-detector configured to detect a signal by receiving light reflected from the high-density optical information storage medium, an optical-path changer configured to convert a travel path of incident light to allow the light emitted from the light source to proceed toward the high-density optical information storage medium, and to allow the light reflected from the high-density optical information storage medium to proceed toward the photo-detector, and a blocking device disposed in an optical path of signal light reflected from a target reproducing/recording layer of the high-density optical information storage medium, passes through the first objective lens, and proceeds toward the photo-detector.

Abstract: A method and an apparatus for reading from a near-field optical recording medium are described. The apparatus includes: an optical system for generating a signal beam and a reference beam; a near-field lens for illuminating the signal beam onto the near-field optical recording medium, for collimating a reflected signal beam, and for reflecting the reference beam; and at least a first detector and a second detector for obtaining a homodyne detection signal from the reflected signal beam and the reflected reference beam.

Abstract: A method for driving an optical pickup apparatus which improves the durability of components that drive a movable lens that moves back and forth between an original position and a drive-limit position and achieves stable operability and an extended lifetime of the optical pickup apparatus performs a first step-drive in which a movable lens moves to an original-restoration start position by being driven a specified distance toward a drive-limit position, a second step-drive in which the movable lens thereafter moves to an original position by being driven toward the original position a distance equivalent to the distance from the drive-limit position to the original position, and a third step-drive in which the movable lens thereafter moves to a default position by being driven a specified distance.

Abstract: An optical pickup apparatus includes an objective lens having a numeric aperture and an incident face. An antireflection coating is formed on the incident face. A collimating lens converts laser light from a laser diode into parallel light, and causes the parallel light to be made incident on the incident face through the antireflection coating. The thickness of the antireflection coating causes a transmittance of laser light that enters the objective lens to be: set at a first predetermined transmittance value, when the numeric aperture is between zero and a first predetermined numeric aperture value; set to correlate linearly with the numeric aperture when the numeric aperture is between the first predetermined numeric aperture value and a second predetermined numeric aperture value; and set at a second predetermined transmittance value, when the numeric aperture is between the second predetermined numeric aperture value and a third predetermined numeric aperture value.

Abstract: Provided is an optical pickup apparatus that stably operates by accurately detecting a fluctuation in a light amount of a laser beam caused by movement of a collimating lens. In an optical pickup apparatus of the present invention, part of a laser beam emitted from a laser device is transmitted through a reflective mirror and detected by a laser beam FMD. An output of the laser device is adjusted based on the output from the FMD. Even when a collimating lens moves during the operation of the apparatus, the change in the light amount of the laser beam caused by the movement is immediately detected by the FMD and the output of the laser device is adjusted. Thus, the light amount of the laser beam radiated on an optical information recording medium is kept constant along a time axis. Accordingly, the optical pickup apparatus can stably perform reading and writing.

Abstract: Disclosed is an objective lens that favorably focuses multiple laser beams having different wavelengths on information recording layers of optical discs, and an optical pickup apparatus including the lens. The objective lens of the invention is provided with a first region for focusing laser beams of the BD, DVD and CD standards. The first region is provided with an annular zone step having a height calculated on the basis of a wavelength of the laser beam of the BD standard, and thus causes chromatic aberration of the laser beam of the DVD standard. This chromatic aberration corrects spherical aberration occurring due to a difference in thickness between coating layers of optical discs. In the invention, the curve surface shape of the first region is adjusted so that the BD and DVD standards can share the aberration for reducing the aberration of the laser beam of the DVD standard.

Abstract: An optical pickup lens for focusing a light beam from a laser light source on an optical information recording medium is a single lens. The optical pickup lens has two surfaces, and a surface R2 opposite to a surface R1 closer to the laser light source has a continuous shape. When the surface R2 has radii h1, h2 and h3 (h1<h2<h3) from an optical axis to a lens periphery, and where sags in the radii h1, h2 and h3 are sag1, sag2 and sag3, and differentials in the sags are ?sag1, ?sag2 and ?sag3, respectively, 0>?sag1>?sag2 and ?sag2<?sag3 are satisfied.

Abstract: An optical-pickup apparatus includes: a laser diode having a first-laser element, which emits a first-laser beam, and a second-laser element, which emits a second-laser beam having a wavelength shorter than a wavelength of the first-laser beam, arranged in the same package; an objective lens to condense the first- and second-laser beams emitted from the laser diode to signal-recording layers of first- and second-optical discs, respectively, the second-optical disc being of a standard different from a standard of the first-optical disc; and a collimating lens arranged in an optical path between the laser diode and the objective lens, the collimating lens configured to change the first- and second-laser beams from divergent light to parallel light, the collimating lens being inclined with respect to optical axes of the first- and second-laser beams so that astigmatism in the first- and second-laser beams is corrected.

Abstract: An optical pickup includes a first source which emits a first beam with a first wavelength; a second source which emits a second beam with a wavelength shorter than the first wavelength; a first collimate lens which collimates the first beam; a second collimate lens which collimates the second beam; a first objective lens which converges the first collimated beam onto an optical disc; and a second objective lens which converges the second collimated beam onto the disc. The first and second objective lenses are arranged in the disc radial direction. The second objective lens is arranged closer to the side of the disc outer circumference than the first objective lens. The first collimate lens is arranged on the right-hand side when the second objective lens is viewed from the first objective lens. The second collimate lens is arranged on the left-hand side when the first objective lens is viewed from the second objective lens.

Abstract: A digital signal reproducing apparatus includes an analog to digital converter for sampling and quantizing a signal read from an optical recording medium in accordance with a reproduced clock having a frequency which is one-half of a channel bit frequency and outputting an obtained digital RF signal, an offset compensation circuit for reducing an offset component in an amplitude direction from the digital RF signal, and a simplified interpolation filter for reconstructing a signal indicating a predetermined pattern recorded in the optical recording medium from the output signal of the offset compensation circuit and outputting the reconstructed signal. A control operation is performed to reduce the magnitudes of respective values shown by first phase error information on a section with the predetermined pattern and by second phase error information on a section other than the section with the predetermined pattern.

Abstract: An optical disc reproducing device is provided which is capable of setting an optimum PR class for the comprehensive frequency characteristic of an optical disc including the recording characteristic and reproducing characteristic. An optical disc reproducing device according to the present invention relates to an optical disc reproducing device which performs reproduction from an optical disc using the PRML method. The optical disc reproducing device comprises a Viterbi decoding unit which generates binary data using maximum likelihood decoding processing based upon multi-value reproduced data obtained by sampling a reproduced signal from the optical disc. The Viterbi decoding unit generates the binary data based upon an optimum PR class determined based upon the multi-value reproduced data and the binary data in a predetermined determination period.