Direct retinal projection systems have been in existence over the past decade and have been applied primarily to niche applications. There has not been wide application or demand at the consumer level, however, due to low resolution, high cost and the inability of current designs to be shrunk to a size that can be conveniently and comfortably worn by a user.
In the military environment, it was recognized that in today's high speed and complex aircraft that it was dangerous for a pilot to have to look down at an instrument panel. Accordingly, a means was developed to present an image of desired information (heading, airspeed, altitude etc.) in a heads up display (HUD) that allowed the pilot to see both the information presented and to look out the aircraft window. For broader applications, the HUD has proven to be expensive and generally low resolution. It would be desirable in many instances to have a similar presentation of information or imagery, in a relatively inexpensive unit that was lightweight, capable of being worn on the head, and allowing for display of imagery as well as allowing a user to see in what is actually in front of him or her. Applications of such a device would be myriad: as a computer terminal display or virtual reality systems, combining infrared imagery to visual light displays so as to see thermal patterns in an object and full color stereoscopic night vision systems,
Ideally, such a display system would be lightweight and comfortable, yet capable of providing high resolution imagery greater than or equal to HDTV. What is needed is a means of taking a video signal and processing it so as to provide the imagery to a device generally of the size of ordinary eyeglasses. It would also be desirable to be able to produce stereoscopic imagery, and to be able to combine two or more images sources in the same display.