Light emitted from a virtual retinal display light source passes through a beamsplitter to a scanning subsystem and on to an eyepiece and the viewer's eye. Some of the light is reflected from the viewer's eye passing back along the same path. Such light however is deflected at the beamsplitter toward...http://www.google.com.au/patents/US6560028?utm_source=gb-gplus-sharePatent US6560028 - Virtual retinal display with eye tracking
