Patent ID: 8164037

Claim:
A dual-mode SAL/IR seeker, comprising: an IR detector configured to detect two-dimensional images of focused incident IR energy to generate at least one IR guidance signal; a positionally-sensitive SAL detector having a system transfer function that converts the spatial displacement of a spot of focused laser energy to a target bearing to generate at least one SAL guidance signal; a primary mirror having a common aperture for collecting and focusing laser energy and IR energy along a common optical path; a secondary mirror/lens in the common optical path that creates a central obscuration of the common aperture, said secondary mirror/lens having an aft side facing the primary mirror and a forward side, wherein the aft side is a secondary mirror configured to permit propagation of laser energy there through to the forward side along a first optical path to the SAL detector and to reflect IR energy along a second optical path to the IR detector, said primary and secondary mirrors configured to focus the IR energy to form the two-dimensional images at the detector, wherein the forward side of the secondary mirror/lens is a lens element, said lens element configured and said SAL detector positioned to form a spot of focused laser energy on the SAL detector; and a spreader positioned in the first optical path between the secondary mirror and the SAL detector away from the aperture stop at the primary mirror and not in the second optical path between the secondary mirror and the IR detector, said spreader configured to spatially homogenize the laser energy to increase the size of the spot of focused laser energy on the SAL detector to set the system transfer function.