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Proceedings Paper

IR molded optics for thermal imaging
Author(s): Yann M. Guimond; Yann Bellec
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Paper Abstract

Umicore IR Glass is a company specialising in the production of chalcogenide glasses and moulded optics. The standard glass compositions are GASIR1 (Ge22As20Se58) and GASIR2 (Ge20Sb15Se65). These materials are transparent in the 3-5 μm and 8-12 μm bands. An industrial process has been developed to produce these two glasses with well controlled properties. The reproducibility of refractive index is for example better than 1.5 x 10-4 at 10 μm. A unique and high precision moulding technology has been developed to produce low cost chalcogenide glass lenses with high performance levels. Spherical, aspherical and asphero-diffractive lenses are manufactured with very accurate surface precision. The form defect of the moulded surfaces can be less than 0.3 μm with a typical roughness of 10 nm. When depositing an antireflection coating onto the moulded lenses, the reflection losses are reduced, raising the transmission to 98%, compared to 70% for uncoated lenses. A durable coating has also been developed as a protection for exposed lenses. Coated asphero-diffractive GASIR optics, used in infrared cameras give good quality images. The performance is comparable to that of an optical system with aspherical germanium. GASIR offers a cost-effective alternative to germanium for thermal imaging, especially for medium to high volume applications, both commercial and military.

Paper Details

Date Published: 10 October 2003
PDF: 7 pages
Proc. SPIE 5074, Infrared Technology and Applications XXIX, (10 October 2003); doi: 10.1117/12.486072
Show Author Affiliations
Yann M. Guimond, Umicore Infrared Glass (France)
Yann Bellec, Umicore Infrared Glass (France)

Published in SPIE Proceedings Vol. 5074:
Infrared Technology and Applications XXIX
Bjorn F. Andresen; Gabor F. Fulop, Editor(s)

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