Patent ID: 7506987
Filing Date: 2009-03-24
Classification: G02B

Abstract:
1. A retroreflector that retroreflects electromagnetic energy, comprising: a body of material, the body having a first surface and a second surface; a plurality of first full-square-sided corner-cube structures on the first surface of the body, the first full-square-sided corner-cube structures each having three facets that lie along planes that are orthogonal to each other; and a plurality of second full-square-sided corner-cube structures on the second surface of the body, the second full-square-sided corner-cube structures each having three facets that lie along planes that are orthogonal to each other; the body being constructed and arranged to be transparent to incident electromagnetic energy at a range of wavelengths and to have a thickness so that an incident electromagnetic energy ray that is incident at one of the first and second surfaces enters the body, and is redirected by both the first surface and the second surface so that both the first surface and the second surface contribute to retroreflection of the incident electromagnetic energy ray, and exits from the one of the first and second surfaces at which the incident electromagnetic energy ray was incident to emit a retroreflected electromagnetic energy ray of the incident electromagnetic energy ray.