Luxeon Rebel Hot/Cold Factor improves solid-state lighting efficiency and simplifies thermal design

Aug. 20, 2009
Date Announced: 20 Aug 2009 -- Improved chip and package technology makes it easier to address ENERGY STAR applicationsSAN JOSE, CA —- Philips Lumileds continues to advance its core LED technology, and recent breakthroughs implemented in the latest LUXEON Rebel LEDs for illumination applications improve efficacy and light output performance at luminaire operating temperatures. Hot/Cold Factor compares the light output of the LED at 100°C Tj and at 25°C Tj — the latter is how LEDs are specified on a datasheet.LEDs in a luminaire are operated at very high junction temperatures, often between 80°C and 110°C. As temperature increases, light output and efficacy decrease. With a Hot/Cold Factor of 0.93, the just released LUXEON Rebel LEDs deliver more light and better efficacy than virtually any other power LED. Typical Hot/Cold Factors range from 0.80 to 0.85 at junction temperatures of 100°C. Maximizing this factor is critical as companies design solid-state lighting solutions that are intended to meet ENERGY STAR requirements.“Hot/Cold Factor is one of the clear differentiators between LEDs,” said Rudi Hechfellner, Director of Technical Solutions. “A high HC Factor can simplify the thermal system design and lower the cost per lumen in the final application.”Hot/Cold Factor charts for all LUXEON Rebel LEDs are available from the datasheets published at About Philips LumiledsPhilips Lumileds is the world's leading provider of power LEDs for illumination solutions. The company's leading light output, efficacy and thermal management are direct results of the ongoing commitment to advancing solid-state lighting technology and enabling lighting solutions that are more environmentally friendly, help reduce CO2 emissions and reduce the need for power plant expansion. Philips Lumileds' LUXEON LEDs are enabling new solutions for shop, outdoor, office, school, and home lighting applications. More information about the company's LUXEON LED products and solid-state lighting technologies can be found at

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