Patent Number: 6,966,660

Title: Article exhibiting dry and wet retroreflectivity

Abstract: A exposed-lens retroreflective article exhibiting retroreflection under dry and wet conditions is provided. The inventive article comprises a first set of optical elements having a first reflective layer disposed on the embedded portion of the elements. The first set contributes mainly to dry retroreflection. The article further comprises a second set of optical elements having a second reflective layer behind a spacing layer. The second set contributes mainly to wet retroreflection. In one embodiment, the first and second sets of optical elements have substantially the same average diameters, refractive index, and density.

Inventors: Buccellato; Gina M. (Eagan, MN), Hedblom; Thomas P. (Eagan, MN), Vandenberg; John L. (Maplewood, MN)

Assignee: 3M Innovative Properties Company

International Classification: E01F 9/04 (20060101); E01F 9/00 (20060101); G02B 5/128 (20060101); G02B 5/12 (20060101); G02B 005/128 ()

Expiration Date: 1/22/02018