Infrared thin-film chip leaps to 72 percent efficiency

The infrared chip prototype has achieved a new record with an efficiency of up to 72 percent. At 930 milliwatts from an operating current of 1 amp, its light output under laboratory conditions is 25 percent higher than that of the chips currently available on the market, which means that future infrared LEDs can be made even more energy-efficient. The efficiency was measured at room temperature and at a dc current up to 1 amp. With a wavelength of 850 nanometers the chip has been designed in particular for infrared illumination applications.

The results from the R&D laboratory in Regensburg have created a new milestone. The prototype of a 1 mm2 chip in infrared thin-film chip technology has achieved an efficiency of 72 percent from an operating current of 100 milliamps. This efficiency, known as wall plug efficiency (WPE), indicates the ration of the radiated power to the electrical input power.

The external quantum efficiency (EQE), in other words the probability of creating a photon and its emission from the LED chip per electron, is as high as 67 percent and remains above 64 percent up to an operating current of 1 amp.

The wavelength of the chip prototype of 850 nanometers is perfect for infrared illumination, particularly for surveillance tasks and use with CCTV cameras. There are also potential safety applications in the automotive sector, such as precrash sensors and illumination sources for night vision systems.

“The way in which the efficiency and brightness have been increased can be transferred from 850 nanometers to other wavelengths,” said Markus Bröll, Project Manager for the development of IRED chips at Osram Opto Semiconductors in Regensburg. “This means that it will be possible to create highly energy-efficient solutions for infrared lighting in the future”. Fewer components will be needed in multi-chip applications, saving both money and energy.

The results of this development work are now being implemented stage by stage. The new chip is expected to go into series production between the start and middle of next year.