INDUSTRY LEDs
Better, brighter phosphors
New formulations increase the quality and intensity of LED lighting BY HERB SCHLEGEL & NICOLE RUTHERFORD FROM INTEMATIX
THROUGHOUT THE OFFICES, homes and hotels of the world, LED bulbs are rapidly replacing incandescent and fluorescent sources, thanks to their high efficacy and long lifetime. These strengths make them a cost-effective choice in the long run, despite higher up-front costs.
As this transition from a niche to a mainstream product is taking place, demand is growing for LED sources that deliver a higher quality of white light. There are various metrics to measure this, but normally a source is considered to be of high quality if it delivers a wide range of Correlated Colour Temperatures
(CCT) and a high Colour Rendering Index (CRI) − and maintains that colour performance over time.
When the LED lighting market was in its infancy, a source with a CCT of 4000K at 70 CRI was deemed acceptable for most applications, but within the last few years retail and hospitality lighting has demanded a CCT of 3000K at 80 CRI. Moreover, with recent advances, these sectors are now asking for CCTs ranging from 2200K to 4000K and CRIs as high as 98.
To meet this demand, manufacturers of phosphor materials must develop
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www.compoundsemiconductor.net June 2014
products for the efficient generation of white light that provides a very wide spectral range.
At Intematix of Fremont, CA, we are doing just that, with an ever-expanding portfolio of phosphors that include green and yellow aluminates, green and yellow garnets, red nitrides and silicates.
These phosphors span a wide range of wavelengths, have very high efficiencies – they can reach a quantum efficiency of more than 97 percent – and can be applied to a wide range of applications from mobile to TV displays and general and automotive illumination.
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