Optical design for an LED traffic signal light

An LED traffic signal light without obvious granular sensation was designed, which had a uniform distribution of luminous intensity in a certain angle range. The emergent rays of the highlighted LED were collimated by a Fresnel lens. A pillow lens was designed and arrayed to achieve the specified direction lighting and a uniform distribution of luminous intensity in a certain angle range by using the Snell's Law. The design was simulated by using the optical design software ZEMAX and the results that the luminous intensity was distributed uniformly were given in both horizontal and vertical angles. The design was proved to meet the design requirement by simulating the imaging of signal light in human eyes and showing the observing effect of eyes. The applications of the design in practical engineering were analyzed in the article.