THE SMART TRICK OF COOLED LONG-WAVE INFRARED LENSES THAT NOBODY IS DISCUSSING

The lens will need to produce a picture that should fill the focal airplane array, or detector, with the IR camera. These arrays are rectangular or sq. in shape, but a lens generates a circular graphic on the focal plane. This necessitates that the lens generate an image that has a diameter equivalent to, or larger than, the diagonal of the array.T