Sony Corporation

Takuya Anzawa

Shinichi Arita

Mitsuhiro Suzaki

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&#x3c;f3/f4&#x3c;2.49 and (2) 1.00&#x3c;|fw1&#x2dc;2/f2|&#x3c;1.50, where f2 to f4 are focal lengths of the second to fourth lens groups, and fw1&#x2dc;2 is a synthetic focal length of the first and second lens groups at the wide-angle end.

Zoom lens and imaging device

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.

Zoom lens and imaging apparatus

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.

Optical pickup, optical disk drive, light detecting apparatus, and signal generating method for optical pickup

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.

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Kanagawa, Japan

Takuya Anzawa