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:
Mar. 16, 1976
Filed:
Nov. 21, 1974
John W Stempeck, Belmont, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
An exposure control system for photographic apparatus of a variety utilizing a pulse driven stepper motor to drive the light regulating elements of an exposure mechanism. The control system utilizes an exposure evaluating network, the output signal from which is converted to binary form and compared against the count output of counter means driven at a predetermined frequency. The system operates to count at one pulse frequency while simultaneously driving the stepper motor at a submultiple frequency until equality is reached with the binary representation. Supplementary counting continues at the one frequency in response to any deviation between the value of exposure derived by the exposure mechanism elements and the value of exposure represented by the binary representation. The deviation is accommodated for by a digitally derived delay corresponding therewith. In effect, a vernier form of binary regulation of exposure is provided.