The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 26, 1976
Filed:
Feb. 28, 1975
AGFA-Gevaert, A.G., Leverkusen, DT;
Abstract
A prism positioned behind the objective rotates at a predetermined frequency. The pulsed light beam produced thereby is split into a first and second pulsed beam, each falling on a photoelectric transducer element. The first photoelectric transducer element is positioned at a distance from the objective which is less than the distance between the film plane and the objective plane by a predetermined distance. The second photoelectric transducer is positioned away from the objective by a distance exceeding the distance between the film plane and the objective plane by the same predetermined distance. The first and second electrical signals produced by the first and second photoelectric transducer are differentiated and stored. The so-stored signals are compared and a control signal for driving a motor in a first or second direction is furnished corresponding to the difference therebetween. The motor drives the objective either closer to or away from the film plane in response to the control signal.