Convolution as a model of the LED irradiance pattern

Abstract

Using a digital image of a distribution of light-emitting diodes (LEDs) or multichip LED, we developed a method to simulate its oblique irradiance spatial distribution on a flat target located at short distances (<20mm). This light oblique irradiance pattern is produced when the LEDs plane or target plane is tilted by an arbitrary angle. The method uses convolution operation between the multichip LED and a special kernel which generates the rotation simulation of the target/LED´s plane. We assumed that LED radiant intensity is directly proportional to the digital imagen. Thus, our method does not requires knowledge about LED data sheet and is not restricted for Lambertian emitters. The model provides the irradiation spatial pattern in function of the irradiation distance for a determined rotation angle. The resulting irradiance patterns on the target, using our method, were pretty similar to the obtained on laboratory experiments.