MEMS shrink digital projector to pico unit

Microvision's pico projector uses MEMS to downsize a digital projector to a palm-size, battery-powered unit.

While digital projector companies progressively downsize their LCDs, making units smaller and with lower power requirements, digital micromirror technology stands poised to leapfrog digital projectors down to cellphone size.

At the International Consumer Electronics Show, Microvision Inc. showcased a prototype of its pico projector, which uses MEMS to downsize a digital projector to a palm-size, battery-powered unit. Microvision replaced a million-mirror MEMS chip with its own, single-mirror MEMS chip, which it claims can be produced cheaply enough to become standard equipment on future cellphones. The projector uses laser scanning borrowed from the company's bar-code reader. Solid-state lasers in the same tiny module with a single digital micromirror simplify projection by not requiring optical lenses.

Control circuitry aims the lasers in a raster-scanning pattern, modulating a coherent beam onto each pixel of the display by moving the single mirror to keep the image in focus.

"We arrange it so the image is always in focus—with no need to adjust it with a lens—from about 200mm [8 inches] to maybe 2m [80 inches] away, so you can literally move the image from the wall to the ceiling, and it will always be in focus," said Russell Hannigan, senior product marketing manager at Microvision.

- R. Colin Johnson
EE Times