Windscreen deviation correcting pilot display

Claim 1

A virtual image display for an aircraft having a windscreen characterized by a symmetrically oriented center line, the display comprising: a light transmissive optical combining element laterally positioned across the windscreen and attached thereto, the combining element being a straight plate including diffraction means serving as a reflecting lens for collimating rays of light impinging thereon; first image generating means located within the cockpit of the aircraft for projecting a virtual image of preselected symbols on the right side of the combining element, with respect to the centerline; second image generating means located within the cockpit of the aircraft for projecting a virtual image of separate preselected symbols on the left side of the combining element, with respect to the centerline, the right and left virtual images being contiguous; a pilot's head being locatable in a space where the field of view of each eye through the combining element including the superposition of an observed object appearing outside the windscreen and the virtual image appearing on the same side of the centerline as that eye thereby avoiding either of the pilot's eyes from seeing the virtual image appearing on an opposite side of the centerline.