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. 08, 2005
Filed:
Aug. 20, 2002
Hiroshi Miyajima, Hachioji, JP;
Masahiro Nishio, Hachioji, JP;
Hiroshi Miyajima, Hachioji, JP;
Masahiro Nishio, Hachioji, JP;
Olympus Corporation, Tokyo, JP;
Abstract
A drive apparatus for an electromagnetic drive type actuator, which includes a movable element, a fixed element, a connection element, a magnetic field generation element, and a drive coil, such that the movable element is caused to oscillate by an interaction between a current flowing through the drive coil and a magnetic field generated by the magnetic field generation element, comprises a drive signal supply element, which supplies to the drive coil a current signal with a periodic waveform that has a frequency substantially equal to a resonance frequency of the movable element and whose current value is zero in a fixed period in one cycle, and an oscillation detection element, which detects an oscillation state based on a timing of a zero-cross point of a voltage waveform between both ends of the drive coil in a period corresponding to the period in which the current value is zero.