Original Publication Date: 1980-Aug-31
Included in the Prior Art Database: 2004-Apr-02
Xerox Disclosure Journal
A retro-reflector, a segment of which is as shown in the figure, consists of a closely packed array of hemispherical surfaces 2 on one side of a sheet 3 of transparent material. On the other side of the sheet is an array of concentric spherical surf aces 4, each spherical surface concentric with a hemispherical surface. The spherical surfaces are coated with a reflective material such as aluminum or silver. Surfaces 2 and 4 have a radius of R1 and R2, respectively; index of refraction n2 of the sheet 3 is higher than nl.