Nikon Corporation

Masaya Nagasawa

Masatoshi Sato

Naoto Inaba

A ranging apparatuscomprises a laser light emitterfor emitting pulsed laser light, a reflected light receiverfor receiving reflected light, a distance computerfor finding the distance from the elapsed time until the reflected light is received, and a distance displayfor displaying this distance. The distance computerhas a counterfor counting the frequency when the reflected light satisfies a specific condition, a table production componentfor producing a frequency distribution table corresponding to distance by adding up the counts, a distance determinerfor determining as the distance to the object of measurement the point when the frequencies in the frequency distribution table exceed a threshold, and a distance selectorfor selecting a specific distance when a plurality of distances are determined, and displaying this distance on the distance display. As a result, when a plurality of distances are calculated, these distances can be appropriately displayed, improving the flexibility and functionality.

Ranging apparatus, ranging method, and opto-electric conversion circuit

An information reproduction method and apparatus reproduces information recorded on an optical disk by projecting a beam of light that has a variable power, determined according to its position in the radial direction of the optical disk. According to a first embodiment of the invention, the projection of the beam of light is moved to the outer perimeter of the radius of the optical disk when it is not possible to move the beam of light so as to correctly follow the information recording tracks formed on the optical disk. As an alternative to the first embodiment (or in addition thereto), the projection of the light beam can be controlled such that the focus of the beam of light is removed from the recording surface of the optical disk when it is not possible to move the beam of light so as to correctly follow the information recording tracks formed on the optical disk. For example, the light beam can be focused on a point further than (i.e., beyond) the surface of the disk. As another alternative, the beam of light is projected at or below the power that does not destroy the recorded information at the innermost perimeter of the optical disk during seek actions that occur when changing the tracks to be reproduced. When the seek actions end and the intended tracks are recorded, the power of the beam of light is set to the power necessary to reproduce those tracks.

Growing community of inventors

Tokyo, Japan

Masaya Nagasawa