Abstract: From an object plane to an image plane along an optical axis, a camera lens including a first lens, a diffractive optical element and a lens module is provided in various embodiments. The first lens has a positive focal power. The diffractive optical element has a positive focal power and a negative dispersion property. A surface that is of the diffractive optical element or the first lens and that faces the object plane side is a convex surface at the optical axis, a surface that is of the diffractive optical element or the first lens and that faces the image plane side is a concave surface at the optical axis. The lens module includes N lenses. At least one of a surface facing the object plane side and a surface facing the image plane side that are of each of the N lenses is an aspheric surface.

Abstract: A zoom lens includes a first lens group with positive refracting power and normally located at a fixed position, a second lens group with negative refracting power and movable in an optical axis direction for zooming, a third lens group with positive refracting power and normally located at a fixed position, a fourth lens group with positive refracting power and movable in the optical axis direction for correction of a focal position for zooming and focusing, and a fifth lens group. These lens groups are arranged in order from an object side to an image side. The zoom lens satisfies the conditional equations (1) 1.00<f3/f4<2.49 and (2) 1.00<|fw1˜2/f2|<1.50, where f2 to f4 are focal lengths of the second to fourth lens groups, and fw1˜2 is a synthetic focal length of the first and second lens groups at the wide-angle end.

Abstract: A zoom lens includes a first lens group with positive refracting power and normally located at a fixed position, a second lens group with negative refracting power and movable in an optical axis direction for zooming, a third lens group with positive refracting power and normally located at a fixed position, a fourth lens group with positive refracting power and movable in the optical axis direction for correction of a focal position for zooming and focusing, and a fifth lens group. These lens groups are arranged in order from an object side to an image side. The zoom lens satisfies the conditional equations (1) 1.00<f3/f4<2.49 and (2) 1.00<|fw1˜2/f2|<1.50, where f2 to f4 are focal lengths of the second to fourth lens groups, and fw1˜2 is a synthetic focal length of the first and second lens groups at the wide-angle end.

Abstract: A zoom lens includes, in order from an object side to an image side: a first lens group that has a positive refractive power and remains stationary in a direction of an optical axis; a second lens group that has a negative refractive power and is movable on the optical axis so as to perform a zoom operation; a third lens group that has a positive refractive power and remains stationary in the direction of the optical axis during zooming and focusing; a fourth lens group that has a positive refractive power and is movable on the optical axis so as to correct fluctuation in imaging position and correct change in imaging position caused by change in object distance; and a fifth lens group that has a positive refractive power and remains stationary in the direction of the optical axis.

Abstract: A zoom lens includes, in order from an object side to an image side: a first lens group that has a positive refractive power and remains stationary in a direction of an optical axis; a second lens group that has a negative refractive power and is movable on the optical axis so as to perform a zoom operation; a third lens group that has a positive refractive power and remains stationary in the direction of the optical axis during zooming and focusing; a fourth lens group that has a positive refractive power and is movable on the optical axis so as to correct fluctuation in imaging position and correct change in imaging position caused by change in object distance; and a fifth lens group that has a positive refractive power and remains stationary in the direction of the optical axis.

Abstract: An optical pickup includes a light source, an objective lens, light detectors, an optical system, and an error-signal generator. The light-receiving surface of at least one of the light detectors has a width extending in a first direction corresponding to a radial direction of an optical disk, and is formed by first to sixth photoreceptors arrayed along the first direction. The first and second photoreceptors, the third and fourth photoreceptors, and the fifth and sixth photoreceptors are disposed axisymmetrically with respect to a center line extending perpendicularly to the first direction. The error-signal generator generates a focus-error signal using a sum signal of detection signals output from the first and second photoreceptors or a sum signal of detection signals output from the first to fourth photoreceptors in a light spot size method, and generates a tracking-error signal using the other sum signal in a differential compensate push-pull method.

Abstract: An optical pickup for recording or reproducing information to an optical disk, includes: a first photodetector for detecting a return light from the optical disk, wherein the first photodetector is configured so that the first photodetector is divided into three portions in a radial direction corresponding to a radial direction of the optical disk and light receiving elements at both end portions in the radial direction are divided into three portions in substantially a track direction perpendicular to the radial direction, so that the first photodetector includes a light receiving element at a central portion in the radial direction and the three light receiving portions at each of both the end portions to be seven in total to output a light receiving element signal based on light reception of the return light as a track error signal generation signal.

Abstract: An optical pickup for recording or reproducing information to an optical disk, includes: a first photodetector for detecting a return light from the optical disk, wherein the first photodetector is configured so that the first photodetector is divided into three portions in a radial direction corresponding to a radial direction of the optical disk and light receiving elements at both end portions in the radial direction are divided into three portions in substantially a track direction perpendicular to the radial direction, so that the first photodetector includes a light receiving element at a central portion in the radial direction and the three light receiving portions at each of both the end portions to be seven in total to output a light receiving element signal based on light reception of the return light as a track error signal generation signal.

Abstract: An optical pickup includes a light source, an objective lens, light detectors, an optical system, and an error-signal generator. The light-receiving surface of at least one of the light detectors has a width extending in a first direction corresponding to a radial direction of an optical disk, and is formed by first to sixth photoreceptors arrayed along the first direction. The first and second photoreceptors, the third and fourth photoreceptors, and the fifth and sixth photoreceptors are disposed axisymmetrically with respect to a center line extending perpendicularly to the first direction. The error-signal generator generates a focus-error signal using a sum signal of detection signals output from the first and second photoreceptors or a sum signal of detection signals output from the first to fourth photoreceptors in a light spot size method, and generates a tracking-error signal using the other sum signal in a differential compensate push-pull method.

Abstract: An optical waveguide device includes a substrate, a metal layer arranged on the substrate, at least claddings arranged on the metal layer and in the claddings dents are formed, at least cores arranged in the claddings, whose end faces are exposed on the sides of the dents, for transmitting lights, optically non-transmissive material coating the inside faces of the dents except the sides on which the end faces of the cores are exposed, at least light receiving elements for receiving lights emitted from the end faces of the cores and inputting the lights into light receiving faces of the light receiving elements.

Abstract: An optical waveguide device includes a substrate, a metal layer arranged on the substrate, a plurality of claddings arranged on the metal layer via grooves, a core, arranged in each of the plurality of claddings, for transmitting lights, optically non-transmissive material coating the insides of the grooves, and optically non-transmissive and electrically insulating material coating the top faces of the claddings.

Abstract: Disclosed herein is an optical disc apparatus for applying a light beam to a surface of an optical disc and detecting a return light beam from the surface of the optical disc. The apparatus includes a light detector for detecting the return light beam having: a light detector having: a first divided area and a second divided area which are divided from each other at the center of the return light beam in a direction perpendicular to a track on the surface of the optical disc; and a third divided area and a fourth divided area which are positioned respectively outwardly of the first divided area and the second divided area in the direction perpendicular to the track. The first and second divided areas are positioned so as not to overlap an area where zeroth-order light and first-order light contained in the return light beam overlap each other.

Abstract: An optical waveguide device according to the invention is provided with a substrate (271), a metal layer (272) arranged on the substrate (271), a plurality of claddings (262) arranged on the metal layer (207) via grooves (205), cores (202) arranged in the claddings (262) for transmitting lights, optical waveguides (201) having optically non-transmissive material (291) coating the insides of the grooves (205) and optically non-transmissive and electrically insulating material (273) coating the top faces of the claddings (262), and light receiving elements (203) for receiving lights emitted from the end faces of the cores (202). In an optical waveguide device according to the invention, dents (204) in which the end faces of the cores are exposed (202) may be formed, the inside faces of the dents (204) being coated with optically non-transmissive material except where the end faces of the cores are exposed.

Abstract: An optical waveguide device according to the invention is provided with a substrate (271), a metal layer (272) arranged on the substrate (271), a plurality of claddings (262) arranged on the metal layer (207) via grooves (205), cores (202) arranged in the claddings (262) for transmitting lights, optical waveguides (201) having optically non-transmissive material (291) coating the insides of the grooves (205) and optically non-transmissive and electrically insulating material (273) coating the top faces of the claddings (262), and light receiving elements (203) for receiving lights emitted from the end faces of the cores (202). In an optical waveguide device according to the invention, dents (204) in which the end faces of the cores are exposed (202) may be formed, the inside faces of the dents (204) being coated with optically non-transmissive material except where the end faces of the cores are exposed.

Abstract: An optical waveguide device according to the invention is provided with a substrate (271), a metal layer (272) arranged on the substrate (271), a plurality of claddings (262) arranged on the metal layer (207) via grooves (205), cores (202) arranged in the claddings (262) for transmitting lights, optical waveguides (201) having optically non-transmissive material (291) coating the insides of the grooves (205) and optically non-transmissive and electrically insulating material (273) coating the top faces of the claddings (262), and light receiving elements (203) for receiving lights emitted from the end faces of the cores (202).

Abstract: An optical waveguide device according to the invention is provided with a substrate (271), a metal layer (272) arranged on the substrate (271), a plurality of claddings (262) arranged on the metal layer (207) via grooves (205), cores (202) arranged in the claddings (262) for transmitting lights, optical waveguides (201) having optically non-transmissive material (291) coating the insides of the grooves (205) and optically non-transmissive and electrically insulating material (273) coating the top faces of the claddings (262), and light receiving elements (203) for receiving lights emitted from the end faces of the cores (202). In an optical waveguide device according to the invention, dents (204) in which the end faces of the cores are exposed (202) may be formed, the inside faces of the dents (204) being coated with optically non-transmissive material except where the end faces of the cores are exposed.