LED Light from Single High-Brightness Chip

Alexei Erchak, Luminus Devices Inc.

LEDs have been around for close to half a century and have made steady progress, not the least of which is their availability in nearly every color. However, challenges remain, including the need in many applications for an array of LEDs that generates enough lumens.

LEDs traditionally are manufactured from compound semiconductors of materials grown using various epitaxy techniques, the most common of which is metallorganic chemical vapor deposition, which produces high-quality material that can convert electrical current into light very efficiently. However, most of the light never escapes the LED, because it is trapped by total internal reflection at the interface between the material with relatively high refractive index and the surrounding medium with relatively low refractive index.