Rangefinding mechanism

Claim 1

In a camera with a focusable main lens and an automatic rangefinder therefor the latter having a photosensitive detector responsive to light from a subject received along two separate optical paths and adapted to transmit a pulse when the received light from the paths is in coincidence and to adjust the lens to focus on an image plane comprising: a main focusing lens for a camera mounted for fore and aft movement relative to the camera for focus adjustment, a first optical system defining a reference path between the subject and a photosensitive detector surface having an optical axis fixed relative to said rangefinder and aimed substantially the same as the optical axis for said main focusing lens, a second optical system for defining a path along which light may be transmitted from the subject to a photosensitive detector surface including a second optical axis movable relative to said first optical axis, a first rangefinder objective mounted for regular periodic movement relative to said second optical system path to generate a scanned movement of said optical axis therefor, a second rangefinder objective drivingly connected to said main focusing lens for movement across said second optical system path for deflection thereof in response to the adjusted focus position of said main focusing lens, electronic timing means connected between said photosensitive detector surface and said periodically moving first objective for measuring the time differential between said coincidence pulse received from the former and said periodic signal received from the latter, and electronic control means connected to receive a signal relative to said measured time differential and having a power driven member responsive thereto for moving said focusing lens in accordance with said amount of measured differential to thereby adjust the focus position of said focusing lens.