Optical arrangements for Head-up Displays and Night Vision Goggles

摘要

An optical arrangement suitable for use in night vision goggles and head-up display units comprising an optical projector (19) which forms a real image of optical data (F) to be displayed and an eyepiece (21) comprising a body of light refractive material (55) with input and output surfaces (59 and 63) and a mirror surface (54) angularly mutually so disposed that rays emanating from the real image and entering the body (59) at its input surface (63) are refracted at the input surface (59), totally internally reflected at the output surface (63), reflected at the mirror surface (54) and finally transmitted through the output surface (63) for viewing by an observer. For night vision goggle use the projector provides an image of the forward scene and incorporates an image intensifier (33). Where the observer is required to have a direct view of the forward scene the mirror surface (54) is a partially light-transmissive, partially light reflective surface at the interface between the light refractive body (55) and a second body of light refractive material (57) having an input surface (67) parallel to the output surface (63) of the first-mentioned refractive body (55).