Optics: measuring and testing – By polarized light examination – With birefringent element
Patent
1993-02-08
1995-03-14
Limanek, Robert P.
Optics: measuring and testing
By polarized light examination
With birefringent element
356376, G01B 902, G01B 1124
Patent
active
053981138
ABSTRACT:
An optical system for measuring the topography of an object includes an interferometer with a multiple-color or white-light source, a mechanical scanning apparatus for varying the optical path difference between the object and a reference surface, a two-dimensional detector array, and digital signal processing apparatus for determining surface height from interference data. Interferograms for each of the detector image points in the field of view are generated simultaneously by scanning the object in a direction approximately perpendicular to the illuminated object surface while recording detector data in digital memory. These recorded interferograms for each image point are then transformed into the spatial frequency domain by Fourier analysis, and the surface height for each corresponding object surface point is obtained by examination of the complex phase as a function of spatial frequency. A complete three-dimensional image of the object surface is then constructed from the height data and corresponding image plane coordinates.
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Hardy David B.
Limanek Robert P.
Zygo Corporation
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