Page 163 - Chalcogenide Glasses for Infrared Optics

Unconventional Lens Fabrication, Aspheric Surfaces, and Kinos 139

uncoated and shows its natural color. Note the kinos on both are
clearly visible.
AMI also worked with Jan Terlow and John Lawson of CBC America
to mold four elements used in an IR zoom lens. The lens changes from an
F/0.8 to F/1.2. Three of the lenses are spherical convex with kinoforms
on the concave side. The fourth element is double concave with one
spherical and one aspheric with a kinoform. The original design used
Amtir 4, but as our molding skills improved, we found we could mold
the elements with Amtir 5. For the same optical performance, only one
element design needed to change going from Amtir 4 to Amtir 5. Again,
a mounting plate for the Palm IR camera was constructed so that we
could use the zoom with the camera. Figure 6.5 shows the zoom mounted
on the Palm IR camera.
Further examples of using the same mold with different glasses
are seen in Fig. 6.6. Lens 1 of the zoom is shown molded using Amtir 5,
Amtir 6, and C1 glass. The lenses are uncoated. Again, the Amtir 6
lens shows its true color. Kinos are clearly visible on all three.
Two sets of DPT Amtir 4 optics were made during the Lockheed
Martin IRAD for a two-element design with a 218-mm focal length. AMI
provided one of the lens mounts and antireflection-coated both sets.
LMCO kept one set and AMI the other. Lens 1 had a 5.7-in diameter
while lens 2 had a 1.8-in diameter. The lenses with mounting are very
heavy. An adapter plate was made so the lens could be used on the AMI
Palm IR. A support was made for camera and lens. Figure 6.7 shows

FIGURE 6.5 CBC America IR Zoom made with molded Amtir 4 glass lenses
mounted on the Raytheon Palm IR camera.