Fabrication of Right Triangular Prism Retroreflectors Through Ultraprecise Single Point Inverted Cutting

Abstract

Retroreflectors (RR) represent optical elements whose primary functionality is to return to the incident light back to its originating source. While inverted cube-corner (ICC) geometry constitutes de facto standard in automotive lighting applications, other RR designs exist. Among them, right triangular prism (RTP) constitutes a viable alternative and therefore, the main intention of the present study was to demonstrate a fabrication means other than the ineffective conventional pin-bundling technology are possible. To address this, a new ultraprecise single point inverted cutting (SPIC) technology — envisioned as a virtual combination between diamond turning and five-axis machining — was introduced as a viable manufacturing option for the fabrication of the RTP RR arrays. While simulation results seem to suggest a slight optical superiority of the RTP RR arrays produced through conventional, rather than SPIC approaches, experimental results have demonstrated that fabricating RTP RR prototypes is not only possible, but it can yield better retroreflective efficiencies when compared to state-of-the-art ICC-based automotive retroreflectors.