High efficiency retroreflective material
First Claim
1. A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including:
- (a) a rectangular base having a length L,(b) two mutually substantially perpendicular tetragonal faces having a line of intersection of length Y, said length Y being less than said length L,(c) a triangular face substantially perpendicular to said tetragonal faces; and
(d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being about sin-1 (0.25/n) to sin-1 (1/n), where n is the refractive index of the reflecting elements;
said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer.
1 Assignment
0 Petitions
Accused Products
Abstract
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 non-perpendicular triangular face forming an angle alpha with the plane perpendicular to the base, the angle alpha being preferably about sin-1 (0.25/n) to sin-1 (l/n), and more preferably about sin-1 (0.35/n) to sin-1 (0.9/n), where n is the refractive index of the reflecting elements, the perpendicular triangular face and the tetragonal face defining an approximate cube corner therebetween and the non-perpendicular triangular face and the tetragonal faces forming a non-orthogonal corner therebetween, the reflecting elements arranged with their base adjacent the surface layer.
206 Citations
24 Claims
-
1. A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including:
-
(a) a rectangular base having a length L, (b) two mutually substantially perpendicular tetragonal faces having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face substantially perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being about sin-1 (0.25/n) to sin-1 (1/n), where n is the refractive index of the reflecting elements; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including:
-
(a) a rectangular base having a length L, (b) two tetragonal faces nearly perpendicular to each other having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face nearly perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being about sin-1 (0.25/n) to sin-1 (1/n), wherein n is the refractive index of the reflecting elements; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer;
wherein said reflecting elements are formed by two perpendicular intersecting sets of parallel grooves, a first set of V-shaped grooves, each having a first and second face and a second set of grooves, each having a third face nearly perpendicular to the surface layer and a fourth face which is not perpendicular to the surface layer. - View Dependent Claims (20, 21, 22)
-
-
23. A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including:
-
(a) a rectangular base having a length L, (b) two mutually substantially perpendicular tetragonal faces having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face substantially perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being in the range of 6°
-65°
;said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer. - View Dependent Claims (24)
-
Specification