Enhanced bidirectional ultraprecise single point inverted cutting of right triangular prismatic retroreflectors

To meet the demands of an increasingly competitive market, automakers are continuously looking for aesthetically appealing and performant lighting components. Among them, retroreflectors constitute the core functional structure of the taillights equipping virtually every vehicle available on the market. For many decades, automotive retroreflectors were locked into the traditional corner-cube (CC) design that is primarily a consequence of the conventional pin-bundling technology underlying their fabrication. However, more recent research developments have identified ultraprecise single point inverted cutting (USPIC) and right triangular prisms (RTP) as potential substitutes for pin-bundling and corner-cube geometry, respectively. By following up the prior work in this area, the main objective of the present study was to propose an enhanced bidirectional USPIC approach that is capable to overcome the shortcomings of the previously employed cutting strategies. The enhanced bidirectional strategy was validated through the fabrication of an array of 11.3 by 11.3 mm consisting of 613 functional RTP structures. The USPIC-generated RTP array was characterized by optical performances comparable to those of a larger-sized CC-based retroreflective surface. Furthermore, the profile of the cutting forces associated with RTP facet generation was correlated in detail with diamond-tool kinematics. Overall, the present progress provides enough incentives for the future development of the USPIC technology.