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:
Feb. 27, 2001
Filed:
Oct. 21, 1998
Applicant:
Inventors:
Patrick Naulleau, Oakland, CA (US);
Kenneth Alan Goldberg, Berkeley, CA (US);
Edita Tejnil, San Carlos, CA (US);
Assignee:
The Regents of the University of California, Oakland, CA (US);
Primary Examiner:
Int. Cl.
CPC ...
G01B 9/02 ;
U.S. Cl.
CPC ...
G01B 9/02 ;
Abstract
In a phase-shifting point diffraction interferometer, by sending the zeroth-order diffraction to the reference pinhole of the mask and the first-order diffraction to the test beam window of the mask, the test and reference beam intensities can be balanced and the fringe contrast improved. Additionally, using a duty cycle of the diffraction grating other than 50%, the fringe contrast can also be improved.