摘要:
In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.
摘要:
There is provided an optical disc device that performs recording on a land and a groove, including an optical path splitter configured to split a luminous flux returning from an optical disc into first and second optical paths, a first detector configured to receive a whole of the luminous flux that has passed through the first optical path, a second detector configured to receive a luminous flux of an inside part of the luminous flux that has passed through the second optical path, a spherical aberration error signal generation unit configured to generate a spherical aberration error signal on the basis of a difference between a first focus error signal obtained on the basis of a detection signal of the first detector and a second focus error signal obtained on the basis of a detection signal of the second detector, a spherical aberration correction unit, and an adjustment unit.
摘要:
A polarization conversion element includes a phase reversal element and a polarization plane rotation element including a liquid crystal layer. The liquid crystal layer has a plurality of regions disposed along circumferential direction with the intersection point of the polarization plane rotation element and the optical axis as the center with alignment directions different from each other. When electric voltage in accordance with the wavelength of linear polarization incident on the polarization plane rotation element is applied, each region rotates the polarization plane of the polarization component transmitted by each region, and thereby converts linear polarization to radial polarization. The phase reversal element reverses, among the first and the second annular portions alternately disposed along the radial direction with the optical axis as the center, the phase of light incident on the first annular portion relative to the phase of light incident on the second annular portion.
摘要:
According to one embodiment, a lens driving device includes a fixed member, a movable member, a support part, and a coil. The movable member is configured to retain a lens and a magnet. The supporting part is configured such that a guide member placed substantially in parallel with a lens optical axis supports the movable member at plural positions symmetric with respect to the lens optical axis while the movable member is movable in a direction of the lens optical axis with respect to the fixed member. The coil is configured such that a driving force is generated for the movable member by interaction with the magnet provided in the fixed member.
摘要:
An optical pickup device includes a laser light source 201, a collimating optical system 202 for converting laser light to parallel light, a focusing optical system 205 for focusing the parallel light onto an optical disc, a light detection unit for receiving returning light returning by reflection of the focused light from the optical disc 101 and outputting a detection signal, and a reflecting mirror 204 disposed between the collimating optical system and the focusing optical system. The reflecting mirror 204 has a reflective surface including three regions having different reflectances. The central region on the reflecting surface meets the other two regions, at positions illuminated by the light focused by the light focusing optical system, in boundary lines that are parallel to a radial direction on the optical disc 101. The reflectance of the central region is lower than the reflectances of the other two regions.
摘要:
Provided is an optical disc device including a focus control unit for performing control so that a convergent point of a main beam converges on a predetermined information layer, a tracking control unit for performing control so that the convergent point of the main beam scans a predetermined track or a predetermined mark sequence on an information layer, a sub beam receiving unit for receiving a sub beam reflected off the information layer and outputting a signal according to an amount of beam received, and a microcomputer for detecting, during a recording operation of recording the information, a focus loss-of-control state where the convergent point of the main beam deviates from the predetermined information layer or a tracking loss-of-control state where the convergent point of the main beam deviates from the predetermined track or the predetermined mark sequence on the information layer.
摘要:
The present invention includes relates to an objective lens used for reproducing and/or recording of information for at least two types of optical discs including high density discs, and has excellent wavelength characteristics, temperature characteristics and tracking characteristics and to provide an optical pickup apparatus employing this objective lens. An objective lens according to the present invention is used for an optical pickup apparatus at least reproducing and/or recording information for a first optical disc having a protective substrate with a thickness t1 and a second optical disc having a protective substrate with a thickness t2 (0.8×t1≦t2). Each of the light fluxes with a wavelength λ1 and a wavelength λ2 enters into the objective lens and a diffractive structure is formed on the at least one optical surface of the objective lens, signs and values of an optical system magnification of the objective lens m1 and m2 for the light fluxes with wavelength λ1 and λ2 respectively are different each other, and the diffractive structure has a positive diffractive action.
摘要:
An optical pickup apparatus comprises a first, second and third light beam sources for emitting first light beams having wavelengths λ1, λ2 and λ3 (λ1
摘要:
An optical information apparatus of the present invention includes: an optical pick-up head including: a light source; a diffraction unit; a condensing unit; a beam splitter; a photodetector; and a tracking error signal generator. An optical recording medium has tracks arranged substantially at a constant pitch. An average of a pitch is tp. When a main beam is placed on the track, a first sub-beam and a second sub-beam are placed between the tracks. The tracking error signal generator performs a differential arithmetic operation with respect to signals output from a light-receiving portion receiving the main beam to generate a first push-pull signal, performs a differential arithmetic operation with respect to signals output from the light-receiving portions receiving the first sub-beam and the second sub-beam to generate a second push-pull signal, and performs a differential arithmetic operation with respect to the first push-pull signal and the second push-pull signal to generate a tracking error signal, in a case where an amplitude of the first push-pull signal obtained at the pitch tp is fluctuated when the light beam is scanned in a direction orthogonal to the tracks of the optical recording medium.
摘要:
A deformable mirror according to the invention comprises a substrate, a reflector which is supported by said substrate and the shape of whose reflecting areas is variable, and a plurality of drive units for independently driving a plurality of regions of the reflector and thereby controlling the distances between said plurality of regions and said substrate. Each of the plurality of drive units comprises a plurality of electrodes disposed over said substrate, a tilt member which is rotated round the axis of tilt by being attracted by the selected one of the plurality of electrodes, and an action member for varying the distance between a specific region of the reflector and said substrate following the motion of the tilt member.