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. 11, 2005
Filed:
Jun. 01, 2001
Kenichi Nakamura, Tokyo, JP;
Eiji Kimura, Tokyo, JP;
Takahisa Tomi, Tokyo, JP;
Advantest Corporation, Tokyo, JP;
Abstract
Disclosed is an apparatus for enlarging the range of modulation frequencies that modulate the variable wavelength light generated by the light source without prejudice to the measurement of optical characteristics. A modified modulation frequency computing section computes modified modulation frequencies by multiplying by the initial modulation frequency fmin by the value obtained by dividing the given phase value by the phase difference between the first phase of the transmitted light resulting from the transmission through the DUT of the incident light of the first wavelength modulated by the initial modulation frequency fmin and the second phase of the transmitted light resulting from the transmission through the DUT of the incident light of the second wavelength modulated by the initial modulation frequency fmin. A modified modulation frequency setting section sets the modified modulation frequency as the frequency of the modulating signal so that the frequencies for modulating the incident light may be wider in range than the initial modulation frequency fmin and that the phase difference may be kept at a value equal to or below the given phase value, and the precision of measuring phase differences can be enhanced.