초록 ▼

A camera with a focusable objective has two secondary projection systems, at least one of which is continuously adjustable, working into a photoelectric comparator which emits a coincidence signal whenever the two projection systems are trained upon the same object along the optical axis of the main

A camera with a focusable objective has two secondary projection systems, at least one of which is continuously adjustable, working into a photoelectric comparator which emits a coincidence signal whenever the two projection systems are trained upon the same object along the optical axis of the main objective. A position sensor, coacting with a swingable mirror in the adjustable projection system, generates a correlation signal whenever the mirror position matches the setting of the main objective as determined by the axial position of a shiftable lens member thereof. With the swingable mirror set in oscillations to scan the object space in front of the main objective, the two signals are generated in the form of short pulses during each scanning sweep and are fed to a phase detector whose output may control a drive motor for the shiftable lens member to bring the main objective into correct focus. The position sensor may include a source of an ancillary light beam, not necessarily within the visible spectrum, and a photoelectric detector therefor; the elements determining the orientation of that light beam (source, detector and/or reflecting surfaces) are then located at least in part on the swingable mirror and on a carrier for the focusing lens member. If the secondary projection systems include a pair of stationary reflectors in a region of the objective in which the light rays from an object on its axis are parallel to that axis when the objective is focused thereon, the swingable mirror can be replaced by a stationary one while the comparator acts as the position sensor.

대표청구항 ▼

In a camera having an objective provided with setting means for varying the position of an axially shiftable lens member thereof to focus the objective upon an object along its axis, said objective further having components between which the incident light rays from an object have predetermined orie

In a camera having an objective provided with setting means for varying the position of an axially shiftable lens member thereof to focus the objective upon an object along its axis, said objective further having components between which the incident light rays from an object have predetermined orientations in a position of said shiftable lens member in which the objective is focused upon such object, the combination therewith of: a pair of ancillary projection systems intercepting incident light rays from an object in line with said objective, at least one of said projection systems including adjustable light-guiding means for varying the relative position of the intercepted light rays, said light-guiding means comprising an oscillatable element mechanically independent of said setting means, said projection systems including a pair of stationary light reflectors between said components respectively directing intercepted light rays toward said oscillatable element and toward a companion element in the other of said projection systems; photoelectric comparison means illuminable by the intercepted light rays from said projection systems for emitting a coincidence signal whenever two images respectively produced thereby register with each other to indicate that said projection systems are trained on the same object; sensing means responsive to the positions of said setting means and of said element for generating a correlation signal upon detecting an agreement between said positions; scanning means coupled with said element for periodically displacing same in a succession of sweeps whereby said correlation and coincidence signals appear in the form of short pulses during each sweep; and phase-detecting means connected to said comparison means and to said sensing means for determining the relative time position of said pulses.