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. 12, 1999
Filed:
Jul. 18, 1996
Lawrence Hendler, Cupertino, CA (US);
Michael P Watts, Portola Valley, CA (US);
Richard A Portune, Sunnyvale, CA (US);
Pixel Systems, Inc., Portola Valley, CA (US);
Abstract
A system includes multiple optical Fourier transform cells which simultaneously scan a device under test. The illuminated area for each Fourier transform cell is small to provide high resolution, while the number of cells is large to cover a relatively wide area and keep inspection speed high. The advantages of optical computing performed by Fourier transform optics also keeps the inspection speed high because illuminated areas are large when compared to the resolution and Fourier transforms are linear shift invariant so that optical measurements can be performed during scanning. In one embodiment, Fourier transform cells are offset from each other perpendicular to the scan direction by less that the width of an illuminated area. This provides complete coverage during scanning of a device under test. Because the illumination for the Fourier transform is collimated, the system is insensitive to focusing errors due to fluctuations in working distance.