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:
Aug. 14, 1990
Filed:
Oct. 28, 1988
James F Biegen, Middletown, CT (US);
Zygo Corporation, Middlefield, CT (US);
Abstract
An interferometric profiler for measuring the topography of a spherical test surface (48), comprises a linearly polarized light source (10), a rotating diffuser disc (18, 20); an optical system (26, 30, 31) for collecting and directing light from the extended light source; a first quarter-wave phase retardation plate (38); a lens (34) for focusing the resultant circularly polarized light beam onto a spherical test surface (48and a spherical reference surface (45), the surface (45) having a reflective coating (46) and an anti-reflection coating; a piezoelectric transducer (80) for varying the relative distance between the spherical test surface (48) and the spherical reference surface (45); means for recombining the test and reference wavefronts (53T,53R) to produce an interference pattern (74); a lens (65) for imaging the spherical test surface (48) and the spherical reference surface (45) onto the photosensitive elements (58) of an imaging device (56); means for optically isolating the imaged spherical test surface (48) and the spherical reference surface (45) and the interference pattern (74); means (38) for converting the test wavefront (53T) and reference wavefront (53R) into a third linearly polarized light beam which has its polarization vector rotated 90 degrees relative to the first linearly polarized light beam; the polarizing beamsplitter (30, 31) directing the third linearly polarized light beam to the imaging device (56); the imaging device (56) sensing the interference pattern (74), a CCTV monitor (72) for viewing the imaged spherical test surface (48) and the spherical reference surface (45) and the interference pattern (74); and means (76) for processing the output of the imaging device (56) to profile the topography of the test surface (48).