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:
Sep. 07, 2004
Filed:
Jun. 25, 2002
Applicant:
Inventors:
Assignee:
Sony Precision Technology Inc., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 3/302 ;
U.S. Cl.
CPC ...
G01R 3/302 ;
Abstract
A sensor coil is provided on a core which forms a magnetic circuit for driving a linear motor, and the core is excited by electrifying the sensor coil at a high frequency. The high-frequency excitation is carried out in such a manner that the sensor coil is not magnetically saturated, and an eddy current is generated in the core. The impedance of the sensor coil is detected in this state and the quantity of a magnetic flux generated in the core constituting the magnetic circuit is detected on the basis of the impedance. Thus, the influence on the magnetic circuit itself is reduced and higher accuracy, miniaturization and lower power consumption are realized.