Patent ID: 6969840
Filing Date: 2005-11-29
Classification: G01J,G02B

Abstract:
1. An imaging optical system comprising: a positive-optical-power primary mirror that receives a light beam from an external source parallel to a beam axis; a negative-optical-power secondary mirror that receives the light beam reflected from the primary mirror; a positive-optical-power tertiary mirror that receives the light beam reflected from the secondary mirror; a negative-optical-power quaternary mirror that receives the light beam reflected from the tertiary mirror, and a positive-optical-power field lens that receives the light beam reflected from the quaternary mirror, wherein the light beam reflected from the secondary mirror passes through a quaternary-mirror central opening in the quaternary mirror and through a primary-mirror central opening in the primary mirror, and wherein the light beam reflected from the quaternary mirror passes through a tertiary-mirror central opening in the tertiary mirror.