Visible light emitting diode technology: high performance, more colors, and moving into incandescent lamp applications

Summary form only given. In recent years visible LEDs have experienced a revolutionary increase in performance. Improvements of about 10X in the red and green spectral regions and about 50X in the amber and blue regions have been demonstrated and are becoming available commercially in high volume. This is enabling visible LEDs, which had been a pervasive technology in low performance "indicator" applications, to move into applications previously dominated by incandescent lamps and other lighting technologies, and to enable new applications. External quantum efficiencies in excess of 20% at 673 nm and luminous performance as high as 50 lumens/watt at 607 nm have been achieved using AlInGaP epitaxial structures grown by MOCVD and utilizing wafer bonding. Incandescent lamps typically have a performance of 15 lumens/watt for white light, and substantially lower performance when filtered to give colors. AlInGaN LEDs with about 18 lumens/watt and 6% quantum efficiency in the green at 525 nn and 2 lumens/watt and 9% quantum efficiency have been demonstrated in the blue at 450 nm. A pulsed nitride laser at 410 nm has also been reported. This talk focuses on the status and trends in high-performance visible LED technology. Issues discussed will include: How much additional performance is plausible? What applications are emerging and might be expected to emerge in the future? How effectively might LEDs ultimately compete with other types of white light sources? and, what role might solid-state lasers have in the emerging visible markets?.