A bulb is adapted to fit over and around a light-emitting diode emitting a light of a first hue in a generally Lambertian radiation pattern. The bulb has a generally spherical shape and a substantially circular external cross-sectional geometry, and further defines an inner cavity with a substantially...http://www.google.de/patents/US7663315?utm_source=gb-gplus-sharePatent US7663315 - Spherical bulb for light-emitting diode with spherical inner cavity
