A real-world viewer comprising: viewing optics positioned along a viewing optical axis (A) for viewing a field of view of the real-world; and an active display overlay unit optically coupled to the viewing optical axis (A) of the viewing optics , for generating images and directing the images along the viewing optical axis (A) of the viewing optics for simultaneous overlaid viewing of the images and the real-world scene as viewed in the field of view through the viewing optics , the active display overlay unit providing luminance of at least 4111.51 cd/ m 2 (1200 fL) to the ocular of the host system with a luminance to the ocular of the host system to power consumption cd/m 2 :mW ratio of at least 20:1 (fL:mW ratio of at least 6:1) or greater, in which the active display overlay unit comprises: an active transmissive display for generating the images along a display optical axis (B); an LED backlight for illuminating the active transmissive display , wherein the LED backlight provides a cone angle of illumination at the active transmissive display that substantially matches a viewing cone angle of the viewing optics , the cone angle being about +/- 10° or less; and a beam combiner aligned with the active transmissive display along the display optical axis (B), and positioned along the viewing optical axis (A) of the viewing optics for directing the images from the active transmissive display onto the viewing optical axis (A) for combining with the field of view that is viewed by the viewing optics in an overlaid manner. viewing optics positioned along a viewing optical axis (A) for viewing a field of view of the real-world; and an active display overlay unit optically coupled to the viewing optical axis (A) of the viewing optics , for generating images and directing the images along the viewing optical axis (A) of the viewing optics for simultaneous overlaid viewing of the images and the real-world scene as viewed in the field of view through the viewing optics , the active display overlay unit providing luminance of at least 4111.51 cd/ m 2 (1200 fL) to the ocular of the host system with a luminance to the ocular of the host system to power consumption cd/m 2 :mW ratio of at least 20:1 (fL:mW ratio of at least 6:1) or greater, in which the active display overlay unit comprises: an active transmissive display for generating the images along a display optical axis (B); an LED backlight for illuminating the active transmissive display , wherein the LED backlight provides a cone angle of illumination at the active transmissive display that substantially matches a viewing cone angle of the viewing optics , the cone angle being about +/- 10° or less; and a beam combiner aligned with the active transmissive display along the display optical axis (B), and positioned along the viewing optical axis (A) of the viewing optics for directing the images from the active transmissive display onto the viewing optical axis (A) for combining with the field of view that is viewed by the viewing optics in an overlaid manner. an active transmissive display for generating the images along a display optical axis (B); an LED backlight for illuminating the active transmissive display , wherein the LED backlight provides a cone angle of illumination at the active transmissive display that substantially matches a viewing cone angle of the viewing optics , the cone angle being about +/- 10° or less; and a beam combiner aligned with the active transmissive display along the display optical axis (B), and positioned along the viewing optical axis (A) of the viewing optics for directing the images from the active transmissive display onto the viewing optical axis (A) for combining with the field of view that is viewed by the viewing optics in an overlaid manner. <EOS>