| 摘要 |
The present invention provides a retroreflective material which has improved retroreflectivity at high angles of incidence. The retroreflective material comprises a transparent surface layer (40) and an array of reflecting elements (20), each of the reflecting elements (20) including a rectangular base (22) having a length L, two tetragonal faces (24,25) nearly perpendicular to each other and having a line (26) of intersection of length Y, the length Y being less than said length L, a triangular face (28) nearly perpendicular to the tetragonal faces; and a non-perpendicular triangular face (30) 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 (20), the perpendicular triangular face (28) and the tetragonal faces (24,25) defining an approximate cube corner therebetween and the non-perpendicular triangular face (30) and the tetragonal faces (24,25) forming a nonorthogonal corner therebetween, the reflecting elements arranged with their bases adjacent the surface layer (40). |
