Output efficiency
Setting a significant benchmark that will positively impact general illumination, projection, and industrial markets, OSRAM Opto Semiconductors’ developers have pushed the efficiency bar for red thin-film LEDs higher by 30%. The chip platform, unveiled as a prototype of the company’s red Golden DRAGON Plus LED, sets the record efficiency boost while delivering 119 lm/W at an operating current of 350 mA (136 lm/W at 70 mA). The 30% increase in the efficiency of the diode results from improved material properties, further development of the thin-film platform, and greater output efficiency (see fig. 1).
The thin-film, InGaAlP chip package measures 1 mm² and emits at a wavelength of 615 nm (λ dominant). Measured efficiency is 44% at 350 mA, 49% at 70 mA, and surpasses 50% at 350 mA at a wavelength of 642 nm. Osram claims there is currently not an LED with higher efficiency at this wavelength.
Some of the advantages of the technology include design options with fewer chips producing the same output and as much as 50% less heat-removal requirements. In essence, as brightness increases, the light sources become smaller. As per the developer of the breakthrough, Osram’s Dr. Wolfgang Schmid, “This will benefit all applications that use high-efficiency red LEDs, particularly projection applications. We expect to start equipping LED products with the new thin-film chips in about a year’s time”. For more details, call OSRAM OPTO SEMICONDUCTORS, San Jose, CA. (888) 446-7726 or visit www.osram-os.com/osram_os/EN.