Importance

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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.sup.-1 (0.25/n) to sin.sup.-1 (l/n), and more preferably about sin.sup.-1 (0.35/n) to sin.sup.-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.

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First Claim