Numerical Simulations of the Light-Extraction Efficiency of LEDs on Sapphire Substrates Patterned with Various Polygonal Pyramids

Abstract

We report a numerical analysis of the light-extraction efficiency (LEE) of light-emitting diodes (LEDs) on patterned sapphire substrates (PSSs). We considered various n-sided, regular convex pyramids, where n is an integer and n ≥ 3. We then considered four cross sections: extruded, subtracted, truncated-extruded, and truncated-subtracted. Ray-tracing simulations were carried out with these polygonal pyramid patterns, and the dimensions of the patterns were systematically varied. Optimized pattern shapes were determined for large LEE. An extruded circular pyramid with a slant angle of 45° was found to be the optimal patterned shape.

Design of LED Luminaire for Parking Garage

“…As for the optical characteristics of the frame surface, the Lambertian surface characterization is applied depending on the optical feature of the white coating panel, which is commonly used for lighting frames. luminaires and LED chips, including ray scattering, absorption, transmission, luminous intensity, illuminance and luminance, etc [7,8]. We conducted a computational simulation for the lighting fixtures, first by designing their geometrical structures using LightTools.…”