High efficiency retroreflective material

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.sup.-1 (0.25/n) to sin.sup.-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.

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.degree.-65.degree.;
• 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.