It's Not There, But It's No Mirage
FOR CLOSE TO ONE YEAR, Seattle's tiny Microvision Inc. has been shipping an unusual breed of head-mounted display to high-paying military customers. Known as a VRD, for virtual retinal display, the gizmo uses a laser, special lenses, and a high-speed scanning mechanism to "paint" moving images directly onto the eye's retina.
Used in flight simulations, the VRD enables a pilot to study maps, pictures, and computer-generated images while manning the plane's controls. The pilot can see his or her whole environment through a clear viewing lens in front of one or both eyes. At the same time, the pilot can study superimposed digital images that appear to float several feet in front of the VRD.
Today, the light source for a full-color VRD takes up most of a midsize suitcase. The scanners and optics are also bulky. But Microvision CEO Richard F. Rutkowski says they'll shrink drastically over the coming year and a half. By the end of September, he'll unveil a prototype in which the scanning assembly will be etched onto a sliver of silicon measuring 0.5 cubic centimeters--just one-hundredth its current size.
In 12 to 18 months, Rutkowski predicts, today's bulky light source will be replaced by tiny laser diodes or light-emitting diodes, which could be fabricated along with the scanner on a single slice of silicon. That would open up consumer applications, such as a pop-up lens on a cellular phone for videoconferencing on the fly.