Forward voltage reduced to one of the lowest values in the world
OSRAM Opto Semiconductors achieved one of the best values in the world in terms of forward voltage for blue high-current chips, leading to an increase in efficiency of up to eight percent. Optimized Indium-Gallium-Nitride (InGaNchips featuring UX:3 chip technology are the basis for blue or white LEDs and are already used in production. OSRAM experts see considerable potential for reducing the value by 20 to 30 millivolts and boosting efficiency by the summer of 2015.
The deep blue OSRAM OSLON Square has a typical forward voltage of 2.87 volts instead of the 3.05 V specified in the data sheet – the lowest typical values in this component class worldwide. A voltage of 2.78 V can be achieved at a solder point temperature of 85° C. Depending on the operating point, this translates into an increase in efficiency of six to eight percent, which can be transferred to the entire UX:3 chip family. These chips, which can be found in all blue and white LEDs, are used in a wide range of applications such as street lighting and industrial lighting. Production of the first optimized chips began in August 2014.
“The reduction in forward voltage was achieved due to a new process in the epitaxy”, said Dr. Marcus Eichfelder, project manager at OSRAM’s Regensburg, Germany facility.
Next steps: further development and transfer to production
According to Dr. Joachim Hertkorn, Epitaxy expert at OSRAM, there is still enormous development potential. Reduction of forward voltage would improve the efficiency of the LED chips by an even greater percentage.
“In the laboratory, we have already succeeded in reducing the forward voltage by as much as 30 mV”, said Dr. Hertkorn. “Due to the speed and efficiency of the implementation of this beginning step, we are confident that the improved process can be transferred to production by the summer of 2015. Any further reductions in forward voltage will be marginal owing to the laws of physics.”