MUNICH, Germany — Siemens light technology subsidiary Osram has developed a LED-based light source for rear projection television, replacing conventional incandescent lamps.

The light source consists of three LEDs - one each for red, blue and green light. The red LED is manufactured in thin film technology while the blue and green one are made in ThinGaN technology. Since these three LEDs each sport a different light emitting angle, they are mounted in an array with special compensating lenses.

According to Osram, the light source suits for all projection systems including DMD (Digital Mirror Device), LCoS (Liquid Crystal on Silicon), and LCD (Liquid Crystal Display). As pure surface emitters, the sources are described as extremely efficient. However, the actual efficiency and power dissipation depends on the specific environment with parameters like driver circuit, light engine, and optical system used, the company said. For this reason, Osram did not specify power efficiency for the devices.

With an average lifetime of 20.000 to 50.000 operating hours, the light source should last as long as the entire TV set without replacing the source, the company said. Volume production is scheduled for first quarter 2007.