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:
Aug. 02, 2011
Filed:
Jan. 28, 2008
Kazuhiko Kato, Tokyo, JP;
Toshiyuki Ogawa, Yokohama, JP;
Yoshitaka Zaitsu, Ichikawa, JP;
Takashi Ushijima, Nagoya, JP;
Kaoru Noguchi, Tokyo, JP;
Atsushi Kandori, Ebina, JP;
Futoshi Hirose, Yokohama, JP;
Kazuhiko Kato, Tokyo, JP;
Toshiyuki Ogawa, Yokohama, JP;
Yoshitaka Zaitsu, Ichikawa, JP;
Takashi Ushijima, Nagoya, JP;
Kaoru Noguchi, Tokyo, JP;
Atsushi Kandori, Ebina, JP;
Futoshi Hirose, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A potential measurement apparatus for measuring a surface potential of an object of measurement detects a change in electric charge induced at a detection electrode due to electrostatic induction by changing a distance between the detection electrode and the object of measurement in accordance with a predetermined period, using a neutral distance as reference, as a signal representing a change in electric current. The potential measurement apparatus includes a first detection unit for detecting a signal representing a fundamental period of the change in electric current and a signal representing a second harmonic period, a second detection unit for detecting information representing a capacitance between the detection electrode at the neutral distance and the object of measurement and an arithmetic unit for computationally obtaining information on the surface potential of the object of measurement, with eliminating an influence of the neutral distance and the capacitance, according to an outcome of detection of the first detection unit and an outcome of detection of the second detection unit.