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:
Jan. 27, 2015
Filed:
Mar. 25, 2013
Fujitsu Limited, Kawasaki-shi, Kanagawa, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A displacement measurement device includes a plurality of light receiving elements each of which outputs a signal corresponding to illuminance of interference fringe, the elements being arranged in a range of two periods of the interference fringe and arranged with an interval based on the period of the interference fringe in a movement direction of the interference fringe, a differential processing unit configured to perform differential processing on predetermined combinations of the signals output from the elements to generate four signals, a phase calculation unit configured to calculate a phase of the interference fringe on the basis of the signals output from the elements; and an output signal selection unit configured to select two signals from among the four signals on the basis of the phase of the interference fringe and select a signal of which absolute value is larger from among the two selected signals.