CD 1964084 E&MP27.051
View of the prisms on the back of Lucite methyl methacrylate reflectors are used for highway lighting at night.
The prisms shown in the illustration have been magnified three times.
The reflectors are based on the optical principle known as retro-directive reflection. Of the two practical types of retro-directive reflectors, the one used is the triple reflector or cube corner.
Original Caption by Science Service
©E.I. duPont de Nemours & Company