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:
Dec. 03, 1991
Filed:
Aug. 01, 1989
Stuart D Perry, Rochester, NY (US);
Jasper S Chandler, Rochester, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
A circuit for driving a focus actuator of the 'double-solenoid' (i.e. twin-coil) variety comprises circuit means for selectively supplying current to one or the other of the actuator's coils in such a manner as to eliminate any dead-band discontinuity in the actuator response while current-switching between the coils. Such circuitry comprises a current source and/or amplifier for selectively providing current to the actuator coils, means for detecting the difference in current flowing in the coils, an a differential amplifier, connected in a feedback loop, for comparing the output of the detecting means with a signal indicating the focal position of a focusing lens. The output of the differential amplifier is used to control the output of the current source, controlling which of the two actuator coils receives current and how much.