LED chip sets help pico projectors bring big displays to small devices
By Margery Conner, Technical Editor -- EDN, February 13, 2009
Pico projectors, LED-based devices small enough to fit into an MP3 player or even a slightly oversized cell phone, were prominently on display at the CES (Consumer Electronics Show) in Las Vegas both this year and last. The obvious use for this type of projector is to show impromptu screenings of your YouTube videos or in-your-face slide shows to a group of friends—in the same way that you currently use full-sized projectors. Unlike the large projectors, however pico devices can make any surface a sign, an art installation, or a call to action and thus may usher in entirely new applications.
An example of a dedicated pico projector is the GP1 from BenQ. The GP1 uses the Luminus PhlatLight LED PT-39 chip set, which includes one red, one green, and one blue LED on each chip of the three-chip set. The chip set works with handheld-projection devices with microsized displays ranging from 0.4 to 0.55 in. wide. The GP1, for example, provides 100 lumens of light to project a 10- to 80-in.wide image onto a nearby wall or screen and boasts a 20,000-hour “lamp” life. The BenQ GP1 pico projector will be available in March for $499.
With its DLP (digital-light-processing) chips, TI is also addressing the pico-projector market. The MEMS (microelectromechanical)-based light-switching engines power the company’s current generation of projectors. The company recently announced a pico-projector development kit that includes a DLP pico-projection engine, a power supply, the necessary video cables, and a three-LED light source. The kit interfaces to the Beagle Board, which employs a TI OMAP (open-multimedia-application-processor) 35x running Linux. The kit sells for $349; the Beagle board, for $149.
