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:
Jul. 25, 1989
Filed:
Feb. 22, 1988
Haruki Ooe, Tokyo, JP;
Kouichi Kobayashi, Tokyo, JP;
Copal Company Limited, Tokyo, JP;
Abstract
A driving unit using an electrostrictive element drives mechanical members such as, for example, a diaphragm and a shutter or a shutter blade having the function of a diaphragm blade by deformation of the electrostrictive element produced when a voltage is applied to the element, and is adapted to obtain a desired deformation quantity from the electrostrictive element regardless of the magnitude of an initial deformation quantity due to hysteresis of the element. A reference switch such as, for example, a photointerrupter operates when a predetermined reference deformation quantity is obtained in an area where the deformation quantity changes linearly in respect to variation of an applied voltage. A voltage obtained by superposing a voltage corresponding to a difference between a desired deformation quantity of the element and the reference deformation quantity on a voltage applied to the electrostrictive element when the reference switch is operated is applied to the electrostrictive element so that a desired deformation quantity is obtained regardless of the magnitude of the initial deformation quantity.