Patent ID: 8459806

Claim:
A triangular pyramidal cube corner retroreflective article, in which a triangular pyramidal cube corner retroreflective element pair group comprising a number of cube corner retroreflective element pairs disposed in a closest-packed fashion on a common plane (S plane) are defined by three base lines (A-B, B-C, and C-A) of respective triangular pyramidal cube corner retroreflective elements, each of the triangular pyramidal cube corner retroreflective element pairs including triangular pyramidal cube corner retroreflective elements having one shared base line (A-B), each of the triangular pyramidal cube corner retroreflective elements having two interior angles (α=∠BAC and β=∠ABC) between the shared base line (A-B) shared by the pair of triangular pyramidal cube corner retroreflective elements and two other base lines (B-C and C-A) that are different from each other, and the triangular pyramidal cube corner retroreflective element pair group comprising: a first element pair group including triangular pyramidal cube corner retroreflective element pairs, in each of which a pair of triangular pyramidal cube corner retroreflective elements is line-symmetrically disposed in relation to the shared base line (A-B); and a second element pair group including triangular pyramidal cube corner retroreflective element pairs, in which each of the element pairs has a shape congruent to a shape line-symmetric to the triangular pyramidal cube corner retroreflective element pair in the first element pair group in relation to a line segment connecting vertexes (C 1 and C 2 ) of the base planes in a direction perpendicular to the shared base line of the triangular cube corner retroreflective element pair in the first element group.