Patent ID: 8593729
Filing Date: 2013-11-26
Classification: G02B

Abstract:
1. A multi-fields of view optical imaging method based on an afocal arrangement configured with an imager, comprising: collimating optical rays for on-axis entry towards a primary mirror of a first group of said afocal arrangement having a front aperture rotationally symmetric about said on-axis, wherein an upper set of rays entering the front aperture will exit the afocal arrangement on a lower side of an exit aperture, and a lower set of rays entering the front aperture exit the afocal arrangement on an upper side, and wherein both sets of rays form an image at a common point of an image plane; first reflecting said rays at the primary mirror of a first group which defines an overall dimension of the front aperture of the afocal arrangement, wherein said primary mirror is an aspheric surface that collects light and reflects it to a next surface, and wherein an inner diameter of the primary mirror is defined by an amount of light that will pass without being clipped by a secondary mirror of the first group, the secondary mirror defining a size of minimum obscuration of the afocal arrangement; second reflecting said first reflected rays at the secondary mirror as second reflected rays, the secondary mirror being annular with aspheric curvature; third reflecting said second reflected rays at a tertiary mirror of said first group as third reflected rays; fourth reflecting said third reflected rays at a quaternary mirror of said first group as fourth reflected rays; forming an intermediate image plane after the quaternary mirror of the first group and prior to a first mirror of a second mirror group of said afocal arrangement, which is a quaternary mirror of the second group; the quaternary mirror of the second group reflects light of said fourth reflected rays towards a tertiary mirror of the second group as fifth reflected light; the tertiary mirror of the second group reflects said fifth reflected light towards a secondary mirror of the second group as sixth reflected light; and said secondary mirror of the second group reflects said sixth reflected light towards a primary mirror of the second group, wherein said primary mirror of the second group collimates a reflection of said sixth reflected light from said secondary mirror of the second group out the back of the afocal arrangement to pass through the imager and form the image at the common point of the image plane.