LEDs keep their efficiency when hot

LEDs keep their efficiency when hot

LEDs are typically tested for efficiency at 25°C. But the resulting data isn't of much use for designing applications like down lights and retrofit lamps, because the internal temperature in such uses may be as high as 80 to 100°C. Most LEDs have significant light output and efficacy losses at these temperatures. That's not so for new Luxeon Rebel emitters, says their manufacturer Philips Lumileds. The new LEDs maintain more than 90% of their light and more than 95% of their datasheet efficacy even at junction temperatures of 85°C.

At the high operating temperatures found in applications like recessed lamps, the new emitters set efficacy benchmarks. The two new Luxeon Rebel LEDs also have correlated color temperatures (CCTs) of 2700K and 3000K that target indoor illumination applications in hotels, shops, restaurants, and homes thanks to use of modern thin-film flip-chip (TFFC) and proprietary Lumiramic phosphor technologies.

More precise color binning make the new LEDs easier to use in architectural applications, says Philips. Most LEDs display inconsistent color off their center viewing axis because their blue photons pass through varying thicknesses of phosphor before exiting the LED. This gives their light different color qualities. This is particularly problematic in linear or wall wash applications so prevalent in the hospitality industry.

Philips says it has solved this problem and provides consistent color and tint at a wide range of viewing angles. The trick is a special process used in conjunction with its Lumiramic phosphor that reduces the variance in color over angle. Over 80% of its emitter production falls within a 3 MacAdam ellipse area within the ANSI bin space, says Philips. This not only contributes to overall color quality, says Philips, but also delivers consistent, repeatable results so lighting designers can confidently design for the most demanding applications.

The new 2700K and 3000K CCT Luxeon Rebel emitters are available now in evaluation and prototyping quantities and high volume production quantities will be available in August 2010.

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