OSRAM Opto Semiconductors, a Munich subsidiary of Siemens AG, has demonstrated prototypes of blue and white LEDs matching the specs of OSRAM’s UX:3 blue LED, which are based on a sapphire wafer.  The new method uses a six-inch silicon wafer as a substrate for gallium-nitride, replacing the costly sapphire substrates commonly used for high-intensity LEDs.  While gallium-nitride-on-silicon LEDs are still a couple years from production, OSRAM is touting the manufacturing breakthrough as another step in significantly reducing the cost of LEDs.

By moving the new process into high-volume production, OSRAM could offer the blue and white LEDs for low-cost home and office lighting applications.  The silicon-substrate LEDs meet the UX:3’s specs of 58 percent efficiency (634 mW at 3.15V).  When the new LEDs are used with a standard phosphor converter in standard packaging as white LEDs, they correspond to 140 lm at 350 mA, with an efficiency of 127 lm/W at 4500K.