The global demand for highly effi cient LED products has grown dramatically over the past 10 years， to the extent that today’s products are rapidly encroaching on the $100 billion fl uorescent light market which has fl ourished over the past 130 years（1）。 Recent improvements in this 40-year technology have resulted in “clean，” reliable and highly effi cient products which are already dominating in many rapidly growing applications. LEDs are now the preferred lighting source for mobile phones， full-motion signs， traffi c signals， automotive dashboards， digital cameras， backlighting units for displays in notebook computers， desktop monitors， fl at-panel televisions， and stadium signage.