Synergistic effect of glass beads in retroreflective materials

Abstract:

Hemispherical coated glass beads are the basic reflective units of retroreflective materials. But, so far, the studies are only limited to the properties of individual glass bead, and have not yet involved synergy between adjacent beads during the retroreflective process. In fact, the presence of synergism makes the reflective properties of the entire film different from that of individual beads. In this paper, the retroreflective ray transmission process was comprehensively analyzed, and a numerical calculation program for glass bead array retroreflective materials was developed taking into account the structural characteristics of retroreflective materials. The variation of retroreflective efficiency with the density of micro beads, the refractive index of the material, and the incident angle of the light were calculated. The results show that the synergistic effect of the bead arrays manifests as inclination effect and shading effect. The former strictly follows this quantitative rule of "the incline factor ", whereas the role of the latter can be quantitatively represented by the shading factor. The inclination effect lonely works at small incident angle, while both inclination effect and shading effect work together when the incident angle is relatively large.