Patent ID: 9677932
Date: 2017-06-13
CPC Classifications: G01J,G01N,G02B

Claim:
1. A spectrograph which includes five mirrors in radiative communication, comprising: a first mirror having a flat mirror reflective surface and positioned to reflect light traversing a prism; a second mirror having a concave-shaped reflective mirror surface and positioned to reflect light received from the first mirror; a third mirror having a convex-shaped reflective mirror surface and positioned to receive light reflected by the second mirror; a fourth mirror having a spheroidal reflective mirror surface and in positioned to receive light reflected by the second mirror; and a field lens comprising a concave mirror surface in combination with a convex mirror surface, wherein light received by said field lens from said fourth mirror enters said convex mirror surface, traverses said field lens, and exits from said concave mirror surface.