Page 167 - Chalcogenide Glasses for Infrared Optics

Unconventional Lens Fabrication, Aspheric Surfaces, and Kinos 143

FIGURE 6.10 Photograph demonstrating the performance of the DPT Amtir 4
218-mm FL IR lens mounted on the Palm IR camera.

performance during temperature excursions. The decision was made
to use Amtir 5 in the infrared system for the new Joint Strike Fighter.
As part of the IRAD, AMI molded several of the 5.38-in-diameter
lenses. The convex and concave surfaces were both spherical. A pho-
tograph of one of the molded lenses is shown in Fig. 6.11.
Another question in molding that has not been mentioned is, How
do you get the molded part out of the mold without it being broken? It is
true the molds are usually coated with a thin film to which the glass part
should not stick. However, these coatings develop open spots with use.
Also, some areas of the mold are almost impossible to reach while coat-
ing. Another factor can be the shape and fragile nature of a lens.