2012 closed with yet more news on the packaged LED front. We've been following the race to mass production among the LED manufacturers working on building gallium nitride LED structures on silicon substrates as opposed to the sapphire or silicon-carbide substrates that are predominant today.
In December Toshiba announced that it was beginning volume production of such an LED based on technology that the company had licensed from Bridgelux. We've since had a chance to digest the data sheets that describe device performance. A 5000K LED with a CRI of 70 produces 112 lumens at 350 milliamps of drive current. That equates to an efficacy figure of 110 lumens per watt. There are also 3000K and 4000K LEDs in the family that come in at 84 lumens per watt. Those performance specs are certainly behind the leading edge of the single-die LED space. But if the move to silicon substrates – especially 200-mm or 8-in substrates – can deliver the expected savings in back-end manufacturing costs, then the parts could prove very attractive in the market.
Cree also made a late year announcement of a multi-die LED designed for directional lighting applications. The 4-die MK-R can deliver as much as 1600 lumens at 15 watts and that puts it in direct competition with some chip-on-board LED arrays. The device also delivers more than 200 lumens per watt in efficacy at low drive currents.
Late in the year we published our top 20 list for the most trafficked stories on our website. If you haven't seen it check out our December news section. LED-based retrofit lamps were the most popular topic, and we certainly had a lot of such news late in the year. In early December we mentioned the new 60W-equivalent lamp from Philips Lighting that is white in the off state whereas the widely sold EnduraLED family is orange due to remote phosphor. It turns out that the warm-white version of the new lamp still uses remote phosphor, although it's hidden on an inner dome that's not visible from the outside. Philips has also gone to a more conventional architecture with LEDs mounted in a planar fashion directed up into the globe. The result is a fairly conventional-looking lamp.
On the business side, the long-standing exclusive relationship between LED manufacturer Philips Lumileds and distributor Future Lighting Solutions has ended. Future wasted no time in adding products from LG Innotek to its line card. And expect to see Lumileds LEDs in other distributors' portfolios soon.