Intematix has announced that independent test lab TUV SUD has conducted 6000-hour tests of some remote-phosphor-based solid-state lighting (SSL) modules that demonstrate 100% lumen maintenance over the duration of the testing. Essentially the demonstration is equivalent to the LM-80 testing of phosphor-converted white LEDs, which is the typical milestone that gates listing for SSL products in programs such as Energy Star and DesignLights Consortium (DLC).
"Energy Star and DLC standards require lumen maintenance of up to 94.1% at 6000 hours of life for LED lighting systems," said Julian Carey, Intematix senior director of strategic marketing. "Our remote phosphor test results showing 100% lumen maintenance at 6000 hours is exceptional and shows remote phosphor to be a very solid design foundation for long life reliability."
Intematix has long claimed that the remote-phosphor approach to SSL product design delivers an increase in efficacy relative to products based on phosphor converted LEDs. Moreover, separating the phosphor from the LED and the heat of the semiconductor junctions can improve color stability. That color consistency has been a reason that companies such as module maker Xicato use remote-phosphor technology and sometimes refer to it as a cold-phosphor approach.
One downside to remote phosphor, however, is the lack of an LM-80-like test standard that can be applied to remote-phosphor optics. Themes on that topic came up in several presentations at The LED Show recently. LM-80 applies to phosphor-converted white LEDs, not to blue LEDs used in remote-phosphor designs or to colored LEDs used in tunable lighting products.
Today, a manufacturer of a remote-phosphor module or light engine can rely on the LM-80 standard for a 6000-hour test duration and use those results to achieve Energy Star or DLC listing. But that puts the manufacturer at a disadvantage in terms of time to market because LED makers begin LM-80 testing as soon as new LED components come off the production line. Moreover, the LED makers only need to do 3000 hours of testing for next-generation follow-on products to LED components that have previously been tested to LM-80. A manufacturer of a remote-phosphor-based product, conversely, must go through the module design and manufacturing cycle before testing can commence.
At The LED Show, Intematix's Carey said, "There is a new standard moving through the IES to bring remote phosphor as a design approach into harmonization with white LEDs from the standpoint of LM-80." He said that the standard will focus on remote-phosphor optics.
Intematix has worked closely with the IES in helping to accelerate the standard, providing the organization with things such as test procedures and results that the company has used to characterize the performance of remote-phosphor modules. Carey expects the standard to be completed around the end of this year.