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. 02, 2010
Filed:
Mar. 01, 2006
Kiyoshi Kurosawa, Tokyo, JP;
Kazuomi Shirakawa, Tokyo, JP;
Kiyoshi Kurosawa, Tokyo, JP;
Kazuomi Shirakawa, Tokyo, JP;
The Tokyo Electric Power Company, Incorporated, Tokyo, JP;
Abstract
An influence on a sensor output is suppressed to a minimum degree even in the case when there is a ripple in a light source, thereby improving the measurement accuracy. In an intensity modulation type optical sensor, light from a light sourceis guided to a sensor head, the intensity of the light is modulated on the basis of an alternating current (AC) measured object (for example, a current i) changing with time, the modulated light is received in a light receiving elementand converted into an electrical signal, and a normalized received signal Xs indicating a degree of modulation is acquired from a ratio of an AC component As and a DC component Ds of the electrical signal to thereby acquiring a value of the AC measured object. Further in this invention, a reference signal Vr is acquired by separating and receiving part of light incident on the sensor head, a normalized reference signal Xr is acquired from a ratio of an AC component Ar and a DC component Dr of the reference signal, and the normalized reference signal Xr is subtracted from the normalized received signal Xs, thereby reducing noises and improving the accuracy.