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:
Oct. 23, 2012
Filed:
Sep. 29, 2009
Hirotoshi Oikaze, Osaka, JP;
Takashi Urashima, Osaka, JP;
Hirotoshi Oikaze, Osaka, JP;
Takashi Urashima, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
The measurement accuracy of an apparatus for measuring the surface shape of an object utilizing a two-wavelength phase-shift interferometry is improved. A low-coherence light source, a plurality of wavelength filters with different transmission wavelengths, an angle control unit and an analysis unit are provided. When performing a two-wavelength phase shift method, the analysis unit detects the wavelength difference between two wavelengths, and corrects a calculated wavelength value and a calculated phase value of one of the wavelengths for preventing a fringe-order calculation error. Next, the angle of the wavelength filters is controlled for making the actual wavelength difference coincident with a designed value. Thus, the wavelength difference between the two wavelengths is continuously controlled to be constant, which enables measurements of surface shapes with high accuracy, even when there are wavelength fluctuations due to the temperature change or the time elapse.