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:
Apr. 04, 2000
Filed:
Nov. 20, 1998
Satoshi Hamada, Habikino, JP;
Minolta Co., Ltd., Osaka, JP;
Abstract
A driving device, for driving a compensation lens of a camera, with a feedback control for an actuator therefor in which it is easy to keep a feedback cycle constant. In the feedback control, the feedback cycle is kept constant by counting the number of PWM pulses for driving the actuator. In case that the actuator is of a type in which it is controlled by more than one PWM pulse trains with different phases, one pulse train with predetermined phase is continuously supplied to the actuator even when the actuator is not driven, where the number of pulses in the one pulse train is counted so as to keep the feedback cycle constant. The actuator preferably employs a piezoelectric element which expands and contracts in response to a wave-form pulse included in the PWM pulse train.