A Study of the Spatial Intensity Distribution of LED for General Lighting

Abstract

The luminous intensity spatial distribution (LISD) of light emitting diodes (LED) can be categorized into two broad types, lambertian type LISD and batwing type LISD. Each type has its own specific characteristics and advantages. Compared to the lambertian type LISD luminaires, the luminaires or light sources with batwing type LISD have some advantages as they can illuminate uniformly a larger area on the target plane and distribute more flux inside the near luminaire area. By considering each single LED as a point batwing emitter, we analyze in this paper the first order design of a luminaire consisting of several LEDs assembled upon a planar surface to be applied in uniform illumination applications such as general lighting. By simulation and first order calculation, we analyze the impact on the illuminance uniformity by different batwing parameters (paramount angle, center versus paramount intensity ratio) and present the optimized batwing design parameters for uniform general lighting applications based on the LEDs luminaire mounting height and the LED-to-LED spacing in different luminaire packaging (string luminaire, ring luminaire, matrix luminaire, etc.).