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Proceedings Paper

High-precision IR molded lenses
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 2.0 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 0.4 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: 26 February 2004
PDF: 8 pages
Proc. SPIE 5252, Optical Fabrication, Testing, and Metrology, (26 February 2004); doi: 10.1117/12.515565
Show Author Affiliations
Yann M. Guimond, Umicore IR Glass (France)
Yann Bellec, Umicore IR Glass (France)

Published in SPIE Proceedings Vol. 5252:
Optical Fabrication, Testing, and Metrology
Roland Geyl; David Rimmer; Lingli Wang, Editor(s)

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