Shape design of efficient retroreflective articles

Retroreflective article is different from other reflecting objects as it returns the incident ray back to the source. This characteristic makes the retroreflectors have many applications in reflective highway signs, reflective vests, and other safety-related items. These articles may have various shapes. However, the quantitative evaluation of performance for the best shape of retroreflector needs much time and cost for manufacturing prototypes and for performance experiments. In this work, we have developed a program for simulating the trace of ray entered into a retroreflective element, in order to determine the optimal shape of retroreflection. We have also proposed new performance criterion of retroreflective articles, which can consider the range of incident angle (RIA), instead of the criterion with the merely retroreflective strength.