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:
Nov. 07, 2023
Filed:
Jul. 08, 2019
Ebara Corporation, Tokyo, JP;
Akira Nakamura, Tokyo, JP;
Ebara Corporation, Tokyo, JP;
Abstract
An output of an eddy current sensor includes an impedance component. A film thickness measuring apparatus obtains film thickness information from the impedance component. Using a non-linear function between the film thickness information and the film thickness, the film thickness is obtained from the film thickness information. When a resistance component and a reactance component of the impedance component are associated with respective axes of a coordinate system having two orthogonal coordinate axes, the film thickness information is a reciprocal of a tangent of an impedance angle which is an angle formed by a straight line connecting a point on the coordinate system corresponding to the impedance component and a predetermined reference point, and a predetermined straight line.