Regensburg, Germany--The prototype of a green light-emitting diode (LED) based on the OSTAR platform from OSRAM Opto Semiconductors is twice as bright as its predecessors and has a luminous surface that is perfectly uniform. OSRAM says this single-chip LED benefits from the latest chip technology and a green phosphor converter. Initial samples are already available, and the process of finding partners to develop appropriate LED office projectors is already under way. The company expects the LED to be launched on the market in the summer of 2011.
OSRAM says that now that RGB LEDs have already conquered the market for picoprojectors, the next segment in their sights is that of office projectors. This has been made possible by the enormous brightness increase of green LEDs. The prototype with a single chip achieves 410 lm and emits at a wavelength of 553 nm. Since a greater proportion of green than red or blue is needed in a projector to produce white light, the increase in the brightness of the green LED has a significant effect on the overall system brightness. With these LED prototypes it is possible to produce systems that provide the system brightness of 2000 lm that is needed for office projectors. LED projectors will therefore be powerful enough for large diagonals of more than two meters. Such applications have only been possible with projectors that use conventional light sources such as high-intensity discharge lamps.
"Doubling the brightness of the green LED is a giant leap forward and removes the restriction that LEDs are suitable only for small projectors," said Volker Mertens, director marketing industry at OSRAM Opto Semiconductors. Apart from providing brilliant image reproduction with saturated colors, LEDs enable projectors to be virtually maintenance-free because they have a life of 30,000 hours. By contrast, high-intensity discharge lamps need to be replaced after only about 400 hours. Projectors with LEDs also respond more quickly to on/off switching, and they support stepless dimming. They can therefore adapt very easily to ambient light conditions and reduce energy consumption. The color space can be set with a high degree of flexibility thanks to electronic control of the individual colors.
SOURCE: OSRAM; www.osram.com/osram_com/News/Trade_Press/LED_OptoSemiconductor/2010/101216_LED_Projection_GreenConversion.html
Posted by:Gail Overton
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