| 摘要 |
FN: 42962CAN7A The present invention provides a retroreflective material which has improved retroreflectivity at high angles of incidence. The retroreflective material comprises a transparent surface layer and an array of reflecting elements, each of the reflecting elements including a rectangular base having a length L, two tetragonal faces nearly perpendicular to each other and having a line of intersection of length Y, the length Y being less than said length L, a triangular face nearly perpendicular to the tetragonal faces; and a nonperpendicular triangular face forming an angle Alpha with the plane perpendicular to the base, the angle Alpha being preferably about sin-1 (.25/n) to sin-1 (1/n), and more preferably about sin-1 (.35/n) to sin-1 (.9/n), where n is the refractive index of the reflecting elements, the perpendicular triangular face and the tetragonal faces defining an approximate cube corner therebetween and the non-perpendicular triangular face and the tetragonal faces forming a nonorthogonal corner therebetween, the reflecting elements arranged with their bases adjacent the surface layer. |
