Truncated-inverted-pyramid light emitting diode geometry optimisation using ray tracing technique

The authors have optimised light emitting diodes (LED) of truncated-inverted-pyramid (TIP) geometry using the ray tracing technique together with electronics simulation. A unique feature of their ray tracing technique is the geometrical treatment combined with a wave optics approach, taking into account refraction, reflection, absorption and interference effects. Their model enables the computation of the angular distribution of the transmitted power of an LED of arbitrary geometry in two dimensions. They have analysed the light power transmitted into a selected angular sector. It is different from known TIP LED experimental results because a wide range of angles has been used in the simulation so that a more detailed picture could be analysed. For example, three major peaks of the light output power in an inclination angle dependency have been discovered. The variations of structural parameters of TIP LEDs allowed the authors to define some other optimal parameters for a variety of purposes.