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. 03, 2009
Filed:
Jul. 26, 2005
Toshihiko Nakata, Hiratsuka, JP;
Masahiro Watanabe, Yokohama, JP;
Shuichi Baba, Yokohama, JP;
Yasuhiro Yoshitake, Yokohama, JP;
Mineo Nomoto, Yokohama, JP;
Toshihiko Nakata, Hiratsuka, JP;
Masahiro Watanabe, Yokohama, JP;
Shuichi Baba, Yokohama, JP;
Yasuhiro Yoshitake, Yokohama, JP;
Mineo Nomoto, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a displacement measurement apparatus using light interference, a probe light path is spatially separated from a reference light path. Therefore, when a temperature or refractive index distribution by a fluctuation of air or the like, or a mechanical vibration is generated, an optical path difference fluctuates between both of the optical paths, and a measurement error is generated. In the solution, an optical axis of probe light is brought close to that of reference light by a distance which is not influenced by any disturbance, a sample is irradiated with the probe light, a reference surface is irradiated with the reference light, reflected light beams are allowed to interfere with each other, and a displacement of the sample is obtained from the resultant interference light to thereby prevent the measurement error from being generated by the fluctuation of the optical path difference.