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:
Mar. 22, 1988
Filed:
Mar. 19, 1987
James F Biegen, Middletown, CT (US);
Zygo Corporation, Middlefield, CT (US);
Abstract
An interferometric profiler capable of accurately measuring the topography of a surface under test (48) employs a laser source (10), with the surface under test (48) ultimately being imaged onto the photosensitive elements (58) of a solid state array camera (56) by an objective lens (34). In accomplishing this, the input beam (12) is transformed by a lens (14) into a spherically converging wavefront (16) which is focused onto a rotating diffuser disk (18) to significantly reduce the spatial coherence of the resultant spherically diverging wavefront (22) which is transformed by a lens (26) into a spherically converging wavefront (28) which is totally reflected by a polarizing beamsplitter (30) to produce a diverging wavefront (32). This wavefront (32) is transformed into a collimated wavefront (36) by the lens (34) and enters a quarter-wave phase retardation plate (38) which has an antireflection coating on this surface (40) with the other surface (42) being a flat reference surface. Objective lens (34) transforms the resulting wavefronts (52R) and (52M) into spherical wavefronts (53R) and (52M) which are transmitted as wavefronts (54R) and (54M) by beamsplitter (30) and fall onto the elements (58) of the imaging device (56).