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Proceedings Paper

Optical Sensor Designs For The Detection Of Cracks In Optical Materials
Author(s): J. R. Hodor; H. J. Decker Jr.; J. Barney
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Paper Abstract

With the advent of new materials for solar cells, such as gallium arsenide, and of thinner materials used in larger flexible solar arrays, such as silicon and protective filter glasses, has come the need for improved methods for the detection of cracks in the optical materials that compose the components of each. Four basic sensor designs have been conceived for use with visibly transmissive, as well as visibly opaque materials. Based upon their specific optical approach, the designs are called brightfield, quasi-brightfield, darkfield reflective and darkfield transmissive. All of these designs rely upon the fact that the crack's cleavage in the material provides a total or near total internal reflection boundary. The basic design simply involves an irradiation source, to which the material is transmissive, and a video camera, which is sensitive to the source's radiation transmitted into and out of the material. Two of the designs have only been demonstrated and await further development, when their need arrives. The other two designs have been developed for specific applications and have been integrated into the production environment at this time. They are proven, viable sensor designs. All of these designs facilitate the extrapolation of the basic crack detection process to future machine vision automation.

Paper Details

Date Published: 22 December 1989
PDF: 9 pages
Proc. SPIE 1168, Current Developments in Optical Engineering and Commercial Optics, (22 December 1989); doi: 10.1117/12.962978
Show Author Affiliations
J. R. Hodor, Lockheed Missiles and Space Company, Inc. (United States)
H. J. Decker Jr., Lockheed Missiles and Space Company, Inc. (United States)
J. Barney, Lockheed Missiles and Space Company, Inc. (United States)

Published in SPIE Proceedings Vol. 1168:
Current Developments in Optical Engineering and Commercial Optics
Robert E. Fischer; Harvey M. Pollicove; Warren J. Smith, Editor(s)

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