Patent ID: 7959427

Claim:
A tool comprised of aberrated cube corner elements for forming a retroreflective lens from a selected transparent material by a selected forming process comprising aberrated cube corner elements, the lens when tilted producing a pattern of retroreflectivity having an International Functional Coefficient of Luminous Intensity, FRO 1 , that is at a maximum value at an observation angle between about 0.2 deg and about 0.5 deg, wherein said cube corner elements of the tool have dihedral angle errors e 1 , e 2 , e 3 and wherein addends T 1 , T 2 , T 3 each having a value which is dependent upon said selected material and forming process are added to the respective dihedral angle errors e 1 , e 2 , e 3 as a result of a change in shape of said selected material during said forming process, and wherein said dihedral angle errors e 1 , e 2 , e 3 are selected such that the resulting dihedral angle errors e 1 +T 1 , e 2 +T 2 , e 3 +T 3 characterize said lens which, when tilted, has an International Functional Coefficient of Luminous Intensity, FRO 1 , that is at a maximum value at an observation angle between about 0.2 deg and about 0.5 deg.