February 24, 2012 — With thermal issues accounting for half of all lighting failures, and costs too high for widespread adoption, assembly and packaging are keys to improving light emitting diodes (LEDs). In "High Brightness LED Assembly Trends, Materials and Issues," consulting firm TechSearch International tracks LED packaging materials and methods, as well as reliability and package efficiency. The report reviews high-brightness LED assembly trends and issues, materials used today, and requirements for the future. Critical issues, including thermal and optical, are addressed.
Packaging materials significantly affect the optical efficiency of LEDs. Reflectivity, transmissivity, and index of refraction can affect the lumens output. Thermal issues account for as much as 50% of the failures in lighting. Packaging material stability (encapsulants and lenses) is also affected by exposure to elevated temperatures, UV, and other wavelength radiation.
There are no standard LED packages. The variety of materials selected, packaging methods, and ultimately reliability make cost-reduction a complex decision-making process.
In the report, TechSearch International shares examples of various packages for high-brightness LEDs to illustrate the diversity in package options.