Technology Research News reports on a possible new display technology: holographic projectors.
"The method could lead to pocket-sized, battery-powered video projectors that produce images whose quality matches that of today's full-sized projectors, according to Adrian Cable, a researcher at the University of Cambridge in England and director of Light Blue Optics Ltd. This type of projector could also be built into a laptop computer, said Cable.
Key to the device's diminutive size is the lack of lenses and high-power light bulbs. Conventional digital video projectors form images by generating a small picture on a transparent microdisplay inside the projector, then shining a high-power light through the microdisplay to a large magnifying lens. In the researchers' design, a two-dimensional hologram is shown on the microdisplay rather than an image, and the projected image is formed by shining a laser beam through the microdisplay, which scatters the light into a particular pattern. "No lenses are required -- the projected image is formed entirely by diffraction," said Cable.
Generating diffraction patterns by computer has been possible since the 70's, but until now has been too slow to do proper video. The researchers have made an algorithm that operates a million times faster than standard algorithms by handling noise in a clever way: instead of trying to reduce noise, they worked to reduce the variation in noise instead, after doing some studies which concluded noise variation was perceptually the worse culprit.So far the prototype systems are just monochrome, but Light Blue Optics plans to do color next, and claim that they will be able to "produce practical pocket-sized video projectors in two to five years". Forget that small PDA screen you use now: use the wall instead.
