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:
Aug. 01, 1978
Filed:
Oct. 19, 1976
Karl-Peter Strauss, Volkmarode, DE;
Rollei-Werke Franke & Heidecke, Braunschweig, DE;
Abstract
Electronic means for controlling the aperture of an electromagnetically operated diaphragm of a photographic camera, especially a single lens mirror reflex camera. The diaphragm aperture is set by a pot-shaped electromagnet. The coil of the electromagnet is supplied with current by an electronic circuit which responds to light falling on a photoelectric converter placed behind the diaphragm, which compares the value of this response to a nominal value resulting from a shutter speed setting and a film speed or sensivity setting, and transmits current in a rapid series of pulses to the coil of the magnet which operates the diaphragm. The pulsing nature of the current applied to the electromagnet tends to cause a slight vibration in the mechanical parts of the diaphragm mechanism, and this vibration helps to overcome the static friction of the moving parts of the diaphragm mechanism, facilitating the setting of the diaphragm to the exact value desired.