An Overview -Advanced Packaging for Solid State Light Emitting Diode (SSLED) Lighting

Implementation of advanced packaging concepts in SSLED lighting has the potential to make a significant

impact on worldwide energy and environmental concerns. In US Department of Energy studies (ref 1),

it has been estimated that, on average, 2.1 quads of energy (the equivalent to 55 million tons of oil) could be saved annually by the implementation of Solid- State Lighting (SSL) nationwide. SSL uses solid-state Light Emitting Diodes (SSLEDs) for general illumination instead of traditional incandescent or fluorescent lighting sources. This paper will present an overview of the issues for current SSLED lighting technologies, and how advanced packaging and integration concepts can address these concerns.

In traditional lighting sources, the majority of electrical power is converted to radiant energy-visible light, IR and UV radiation and only a small fraction is

converted to heat (~ 8 to 42%). However in SSLEDs, the electrical power is converted to visible light (~20%) and heat (~80%). Heat generated in Light Emitting Diodes (LEDs) has to be conducted away from the source or else the device junction temperature will rise. Without adequate thermal management, both the device performance and lifetime will be adversely affected by higher junction temperature.

High cost of SSLED-based lamps is another major factor preventing the widespread use of SSLED lighting. Currently LED lamps cost 50 to 100 times more than traditional lights. Despite the considerably longer lifetime of an LED light, the average consumer

is not willing to pay the higher upfront cost.

The key to addressing these concerns is having a packaging solution that will provide adequate thermal management at a lower price. In this paper, the current and advanced packaging solutions are presented.