Wide-field three-mirror collimator

Abstract

An improved three mirror collimator (or telescope) having a focal plane (38) positioned on a first side of the optical axis (44) and which directs a diverging beam of radiation upon concave tertiary mirror (36) which is also positioned on the first side of optical axis (44) and which reflects the received radiation to an on-axis convex secondary mirror (34) in a converging pattern. Secondary mirror (34) reflects the received radiation in a first converging, then diverging pattern upon concave primary mirror (32) which is positioned on the second side of optical axis (44). Primary mirror (32) reflects the received radiation as a collimated beam to the real entrance pupil (30) which is located either on or near the optical axis but which need not be precisely centered on the optical axis. When used as a telescope the radiation enters the entrance pupil (30) as a collimated beam and is received by primary mirror (32). Primary mirror (32) reflects the radiation in a first converging then diverging pattern upon on-axis secondary mirror ( 34) which, in turn, reflects the radiation upon off-axis tertiary mirror (36). The tertiary mirror (36) then reflects and focuses the received radiation upon focal plane (38).

Dependencies are inferred from the claim text.