Osram Moves to 85°C Binning

OSRAM Opto Semiconductors announced a new high-temperature Oslon Square LED that is measured and binned at 85°C, targeting commercial and residential lighting applications.

Traditionally, LEDs have been binned at a junction temperature of 25°C. With an eye toward capturing more of the industrial lighting and luminaire replacement retrofit markets, Osram Opto Semiconductors announced its Oslon Square LED is now being binned at 85°C. This is closer to the ambient temperature experienced by major lighting applications such as spotlights and retrofit light sources.

But in reality the company is playing catch-up, since three of its four major competitors have been "hot-binning" for well over a year.

Both Philips and Cree announced the approach back in early 2011. Hot-binning opens the door for LEDs to expand into application areas that can benefit from a smaller footprint enabled by higher junction temperature tolerances.

Osram claims that its new chips feature improvements in the phosphor conversion technology and that they can withstand high ambient temperatures while maintaining the color point of each LED in the luminaire. "We've been working on new phosphor blends and are able to produce significantly thinner converter layers, allowing for the production of LEDs that withstand higher ambient temperatures," according to Marc Dyble, Product Marketing Manager at Osram, who spoke with us in a recent phone interview. "The thinner layers better dissipate the heat, and this offers a ripple effect of benefits that include far less aggressive thermal designs, a smaller luminaire footprint, and higher lumen output with fewer LED chips, all of which contribute to lower cost," Dyble said.

Philips Lumileds and Cree pioneered

As we mentioned, Osram's competitors have been hot-binning LEDs for some time now. In February 2011, Philips Lumileds (sponsor of this site) announced its Luxeon S chips, stating they were "hot tested." All Luxeon A LEDs use the 85°C method for binning. Philips Lumileds said these are meant to offer "illumination grade" LED light sources. The company focused on a "freedom from binning" marketing message. Luxeon A LEDs have been in high-volume production since May 2011. When, in April 2011, Cree announced its XLamp CXA2011 LED array that was hot-binned at 85°C, the company referred to this as a "real world" specification. Other Cree chips came in December 2012 with the announced XM-L2, also binned at 85°C.

For its part, Samsung has been making LEDs since 2009 and announced its entry into the US lighting market in May 2011. The company also offers hot-binning for a wide range of its high-powered LED components (SPHWHTL3D30xx series).

We have found no (public) mention from Nichia as yet on hot-binning, and are awaiting a response as of this writing.

This blog over at Kiwi Lighting has a good explanation of how 85°C binning can simplify the design process for the LED customer designing a luminaire. In fact 85°C is as arbitrary a point as 25°C was before it. For some applications (e.g. freezer lights and outdoor lighting) the designer is still going to need to do some math.

With Osram's entry into the hot-binning club, characterizing LEDs at 85°C has become a clear industry standard.