ABSTRACT
This type of lens is used in the cockpit of an aircraft to image a cathode ray tube (CRT) into the pilot’s eyes. It is similar to a huge eyepiece, with the exit pupil being at the pilot’s eyes. This pupil should be large enough to encompass both eyes and allow for some head movement. Typical specifications for such a system would be
Entrance pupil diameter
6 in.
Pupil distance to lens
25 in.
Angular resolution
Center
1 min arc
Edge
3 min arc
Field of view
25°
Instantaneous field of view
20°
Maximum distortion
5%
