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:
Feb. 13, 2007
Filed:
Feb. 28, 2003
Kiyoshi Kurosawa, Tokyo, JP;
Yoshiharu Hiroki, Tokyo, JP;
Yoshihiro Konno, Tokyo, JP;
Masaru Sasaki, Tokyo, JP;
Kiyoshi Kurosawa, Tokyo, JP;
Yoshiharu Hiroki, Tokyo, JP;
Yoshihiro Konno, Tokyo, JP;
Masaru Sasaki, Tokyo, JP;
The Tokoyo Electric Power Company, Inc, Tokyo, JP;
Namiki Precision Jewel Co., Ltd., Tokyo, JP;
Abstract
A current measuring apparatus comprises a current detection unitand a photoelectric converter. The current detection unitcomprises an optical fiber sensorextended or looped around a conductor. A reflective filmis attached to one end of the sensorso that light can be reflected by the end of the sensor. The current detection unitfurther comprises a first Faraday element, a light-transmitting birefringent member, a first optical fiber, a second optical fiberand a lens. The Faraday elementrotates a plane of polarization of the incident light through about 22.5°. The birefringent memberfunctions to separate the light emitted from the sensorinto an ordinary ray Land an extraordinary ray Lthat are orthogonal to each other, and to transmit linearly polarized light Lemitted from a light source. The lensis provided between the elementand the birefringent member. Focal points of the lens are formed at core portions of an input endof the sensorand an end faceof the first optical fiber. With this arrangement, the number of components is reduced and the apparatus is reduced in size.