SSL Technology Update: July 17, 2012

July 18, 2012
In this week's SSL Technology Update: Cree refreshes a popular LED family; Soitec and Silian join forces to focus on low-cost template wafers; and Seoul attacks lumen density.

Cree continues to expand the scope of LED offerings based on its third-generation, silicon-carbide-based manufacturing platform that it calls SC cubed. The latest product, the XLamp XP-G2 family, is footprint-compatible with the workhorse XP-G family that has been used in applications ranging from street lights to flashlights.

The new LEDs are mechanically and optically compatible with existing TIR lenses and reflectors developed by Cree's customers. This means the components can be dropped into existing XP-G designs and deliver a 20% gain in lumen output and efficacy. Product developers might also choose to do minor redesigns of existing products and reduce the number of LEDs used in the product. Cree presented an example in a PAR38 retrofit lamp that currently uses 7 XP-G LEDs in which a new design might require only 3 XP-G2 LEDs, driven at higher current, but delivering comparable output and efficacy.

Moving a step back into the LED manufacturing space, Soitec and Silian announced a joint development agreement to produce gallium nitride template wafers. Soitec says that it has developed a faster, lower cost way to produce template wafers using hydride vapor phase epitaxy, rather than the more traditional metal-organic vapor phase epitaxy. The partners plan to apply that technique to Silian's sapphire substrates and deliver template wafers later this year.

The template wafers will then be completed by LED makers using metal-organic vapor phase epitaxy tools to grow the light-emitting layers. By accelerating the early part of the epitaxial process, the partners said they will lower component costs and spur solid-state lighting deployment.

Seoul Semiconductor is also refining its manufacturing technology focused on a 5x improvement in lumen density. The company is utilizing a non-polar plane in the gallium nitride crystal to reduce electrical resistance and increase electrical and optical efficiency. The patented nPola approach has been under development for 10 years, but Seoul still can't say when it will move from the lab to products.

Following baseball's mid-summer all-star classic, we will close with a quick story relating to America's pastime. US Cellular field, formerly New Comiskey Park and home of the Chicago White Sox, has new 2x2-ft LED fixtures that replaced fluorescent T12 lamps in concession stands and other areas. The 50W PolyBrite Borealis fixtures replaced 78W fluorescents.