Patent ID: 6229598
Filing Date: 2001-05-08
Classification: G01C,G01S

Abstract:
A distance measuring apparatus for measuring a distance to a target, the apparatus comprising:a housing;a lens mounted to the housing so that light passing through the lens enters or exits the housing;a light emitting element disposed in the housing for emitting pulsed light toward the target through the lens;a photo-detective element disposed in the housing;an optical system including:a first optical path provided in the housing for emitting pulsed light from the light emitting element to the target through to the lens;a second optical path provided in the housing for receiving pulsed light from the lens to the photo-detecting element, wherein the distance is measured based on a timing difference between a first time at which a pulsed light is emitted from the light emitting element toward the target and a second time at which pulsed light reflected off the target is incident on the photo-detecting element, after the pulsed light is emitted,wherein the lens is positioned in the path of both the first and second optical paths;a filter for adjusting light quantity arranged in the housing, in the second optical path;a light flare detecting means for detecting the existence of light flare based on an output from the photo-detecting element, wherein the light flare to be detected is generated in response to the pulsed light in the first optical path reflecting off at least an inner surface side of the lens, and wherein the second optical path guides the generated light flare to the photo-detecting element;a reference optical path extending in the housing from the light emitting element to the photo-detecting element, without passing through the lens; anda shutter disposed in the reference optical path, wherein a pulsed light emitted from the light emitting element becomes incident on the photo-detecting element when the shutter is open.