Abstract: A tool for producing a pattern of highly accurate optical quality surfaces and the method of making same from a series of bi-metallic pins. A high strength metal pin is coupled to a slug of metal of lesser strength capable of being accurately scribed. The supporting pin blank preferably is magnetic stainless steel and the slug is of copper. A group of such bi-metallic pins then is placed in an appropriate fixture after which an optical configuration, such as the three faces of a cube-corner element, are scribed into the copper ends. A completed tool may then be electroformed to produce an electroformed tool from an array of the like or different pins, arranged in various patterns.

Abstract: Disclosed herein are an improved method and apparatus for continuously embossing a repeating pattern of precise detail, in particular, cube-corner type reflector elements, on one surface of a single sheet or on one surface of a laminate of transparent thermoplastic materials, to form retroreflective sheeting. A continuous embossing tool in the form of a flexible thin metal belt or cylinder has on its outer surface an embossing pattern which is the reverse of the precision optical pattern to be formed. The embossing tool is continously moved at a predetermined speed along a closed course through a heating station where the temperature of a portion of the embossing tool is raised to be above the glass transition temperature of the sheeting or laminate and a cooling station where the heated portion of the embossing tool is cooled while in a relatively planar condition to be below that glass transition temperature.