Abstract: An optical system has an objective lens condensing a light beam from the light source on a recording layer selected from the plurality of recording layers of the optical disk, and leading a returning light beam reflected by the selected recording layer to a predetermined position; an aberration detecting part detecting a physical amount relative to spherical aberration based on an output signal of the photodetector; an aberration correcting part correcting the spherical aberration based on the physical amount; and a processing device carrying out at least the information reproduction o from among information recording, information reproduction and information deletion with the use of the output signal of the photodetector.

Abstract: An optical system for efficiently extracting plural signal beams from a bundle of rays reflected from a multilayer optical disc.

Abstract: A wavefront aberration compensation element includes a wavelength selection phase plate having a plurality of phase steps having various thicknesses at various areas, a liquid crystal layer for obtaining a prescribed wavefront aberration, and a pair of first and second electrode layers having the liquid crystal layer disposed therebetween, wherein either one of the wavelength selection phase plate and the pair of first and second electrode layers having the liquid crystal layer disposed therebetween is stacked on the other.

Abstract: An airbag apparatus includes an airbag that includes a bag body provided with an insert hole for receiving an inflator and a sealing cloth arranged to cover a peripheral area of the insert hole. The sealing cloth includes on the location corresponding to the insert hole a through hole for receiving the inflator.

Abstract: The present invention discloses an optical system for extracting signal light components from a beam including the signal light components and stray light components. The optical system includes a condensing optical element situated on an optical path of the beam for condensing the beam, a polarization changing unit for changing the state of polarization of at least one of the signal light components and the stray light components included in the incident beam transmitted through the condensing optical element, and an extracting element for extracting the signal light components included in the beam transmitted through the polarization changing unit.

Abstract: The present invention discloses an optical system for extracting signal light components from a beam including the signal light components and stray light components. The optical system includes a condensing optical element situated on an optical path of the beam for condensing the beam, a polarization changing unit for changing the state of polarization of at least one of the signal light components and the stray light components included in the incident beam transmitted through the condensing optical element, and an extracting element for extracting the signal light components included in the beam transmitted through the polarization changing unit.

Abstract: A tilt sensor for detecting information related to a tilt of an object to a reference plane is disclosed. The tilt sensor includes a diffraction element disposed that diffracts an incident light at diffraction efficiency depending on the incident angle, and a photo detector that detects a diffraction light diffracted by said diffraction element and outputs an photoelectric signal. Since the diffraction efficiency of the diffraction element changes as the incident angle changes, the intensity of the diffraction light from the diffraction element changes. As a result, the photoelectric signal output from the photo detector contains the information related to the tilt of the object.

Abstract: A multi-layer data storage medium includes a plurality of recording layers in which a guide groove, where data is stored, is formed in a spiral manner, and each center of the plurality of the recording layers is eccentric to a center of the multi-layer data storage medium in a different direction.

Abstract: An optical pickup device includes a light source unit an optical system which leads a return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to a recording surface of a corresponding storage medium and a photodetector arranged at the light-receiving location. The light source unit includes a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other, and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

Abstract: The present invention discloses an optical system for extracting signal light components from a beam including the signal light components and stray light components. The optical system includes a condensing optical element situated on an optical path of the beam for condensing the beam, a polarization changing unit for changing the state of polarization of at least one of the signal light components and the stray light components included in the incident beam transmitted through the condensing optical element, and an extracting element for extracting the signal light components included in the beam transmitted through the polarization changing unit.

Abstract: An optical pickup apparatus for shining light on an optical disk having two recording layers and for detecting reflected light from the optical disk includes a light source, an optical system situated on a path of a light beam returning from the optical disk inclusive of light reflected by a first recording layer of the optical disk and light reflected by a second recording layer of the optical disk, the optical system including a light condensing optical unit to turn the returning light beam into a condensing light beam, and a light beam regulating unit to extract from the condensing light beam a partial light beam corresponding to part of a cross section of the condensing light beam, and one or more photo detectors, situated between a position where the light reflected by the first recording layer contained in the partial light beam is condensed and a position where the light reflected by the second recording layer contained in the partial light beam is condensed, the one or more photo detectors having a fi

Abstract: An optical pickup device includes a light source unit an optical system which leads a return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to a recording surface of a corresponding storage medium and a photodetector arranged at the light-receiving location. The light source unit includes a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other, and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

Abstract: A multi-layered information recording medium used in an information recording/reproducing apparatus applicable to both a single-layer information recording medium and an arbitrary multi-layered information recording medium is provided. The multi-layered information recording medium has a plurality of recording layers, and each of the recording layers has a guiding groove formed at a track pitch defined as a quadratic function of disk thickness (i.e., the distance from the light incident surface) of the associated recording layer. The guiding grooves of the recording layers are formed such that the track pitch of a reference recording layer having a disk thickness closest to that of the single-layer information recording medium is the smallest amongst the multiple recording layers.

Abstract: The head-protecting airbag device (M1) includes an airbag (12) provided with a gas admissive portion (13) and a non-admissive portion (23). The gas admissive portion (13) includes a gas feed passage (14) for feeding inflation gas G toward both front and rearwards of the vehicle, and a plurality of vertical chambers (17) juxtaposed along front-rear direction of the vehicle. Each of the vertical chambers (17) includes a communication port at its upper end for communicating with the gas feed passage (14). The substantial lengths of a vehicle's outer wall (13b) and an inner wall (13a) of the airbag (12) are differentiated from each other by a belt (31) in the periphery (19) of the communication port (18). Thus the periphery (19) of the communication port (18) guides inflation gas (G) obliquely down and toward the vehicle's exterior (O) when inflation gas (G) flows into the vertical chamber (17) via the communication port.

Abstract: An extraction optical system for use in an optical pick-up device receiving a reflected light from an optical disc having a plurality of recording layers is provided. The extraction optical system extracts from a light in which a signal light component from an access target recording layer of the plurality of recording layers and a stray light component from a recording layer other than the access target recording layer of the plurality of recording layers are mixed, the signal light component from the access target recording layer of the plurality of recording layers. The extraction optical system includes a condensing optical element arranged in an optical path of the light and condensing the light, and a selective optical system to which the light condensed by the condensing optical element is incident and reflecting a light primarily containing the signal light component.

Abstract: An optical pickup device includes a light source unit an optical system which leads a return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to a recording surface of a corresponding storage medium and a photodetector arranged at the light-receiving location. The light source unit includes a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other, and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

Abstract: An optical pickup unit for recording information on and/or reproducing information from a multilayer information recording medium including multiple recording surfaces in each of which a guide groove on which the information is to be recorded is spirally formed is disclosed. The optical pickup unit includes a light source, a diffraction element configured to split the light beam emitted from the light source into a main light beam and first and second sub light beams, an objective lens for focusing the main and sub light beams onto a recording surface of the multilayer information recording medium, and multiple light receiving elements each divided into light receiving parts so as to receive the main and sub light beams reflected from the recording surface. The focused first and second sub light beams are disposed at respective positions at least 3/2 tracks away from the focused main light beam on the recording surface.

Abstract: An optical pickup device includes a light source unit an optical system which leads a return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to a recording surface of a corresponding storage medium and a photodetector arranged at the light-receiving location. The light source unit includes a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other, and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

Abstract: A head-protecting airbag according to the present invention is normally folded and housed in an upper edge of windows inside a vehicle, and includes a gas admissive portion inflatable with inflation gas from inflator and a non-admissive portion admitting no inflation gas. The gas admissive portion includes a shielding portion for covering the vehicle's interior side of the windows upon deployment of the airbag. The shielding portion includes a plurality of vertical chambers each of which is located vertically upon deployment of the airbag, and at least one horizontal chamber which is located along longitudinal direction of the vehicle upon deployment of the airbag. The horizontal chamber is located between at least one neighboring pair of the vertical chambers in the vicinity of vertically middle position of the pair of the vertical chambers, thereby communicating the pair of the vertical chambers.

Abstract: An airbag for head-protecting airbag device according to the present invention is normally folded and housed in an upper edge of windows including a front pillar. The airbag includes a gas admissive portion. An inflatable shielding portion of the gas admissive portion includes a plurality of protection portions, at least one of which located toward front end of the airbag acts as front protection portion, and remaining protection portions located rearward of the front protection portion act as rear protection portions. The front protection portion includes a plurality of vertical chambers juxtaposed along the front-rear direction of the vehicle, and each of the vertical chambers is arranged vertically. The rear protection portions include a plurality of horizontal chambers juxtaposed in the vertical direction, and each of the horizontal chambers is arranged along the front-rear direction of the vehicle.