Greetings everyone,(adsbygoogle = window.adsbygoogle || []).push({});

I need to calculate the efficiency of an LED without a plastic dome, thus total internal reflection is a limiting factor in this case. The book asks me to show that TIR at the interface with air reduces the emission efficiency by the factor 1-cosθ where θ is the critic angle. In addition to that how can I calculate the solid angle of a cone with half angle say β. Any help is appreciated.

Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Efficieny of an LED

**Physics Forums | Science Articles, Homework Help, Discussion**