A head-mountable image display system provides an image to a user's eye separate from ambient light. The system includes an optical relay having an optical pathway to receive light from a display element. The optical relay also permits passage of ambient light toward the user's eye. An eyepiece assembly...http://www.google.de/patents/US6356392?utm_source=gb-gplus-sharePatent US6356392 - Compact image display system for eyeglasses or other head-borne frames
