Patent ID: 6804065
Filing Date: 2004-10-12
Classification: B23B,B29C,B29D,B29L,G02B,Y10T

Abstract:
A working method of a die for use for a Fresnel lens, the method being intended to work in an original die plate a Fresnel molding groove having wall surfaces corresponding to a lens surface and a non-lens surface of the Fresnel lens,wherein there is used a cutting tool in which one piece of edge line continuing to a blade end is constructed as a cutting edge; and the blade end has formed therein a notched portion which connects the one piece of edge line and another piece of edge line, whereby while a relative rotating movement around a center line of the die is being made between the cutting tool and the original die plate, the cutting tool goes on to be fed into the original die plate with the cutting edge being used as a leading blade so that the wall surface corresponding to the non-lens surface of the Fresnel molding groove is gradually cut from an upper end thereof by the notched portion; wherein a concavities/convexities configuration of cutting trace is formed in the wall surface by the notched portion, which makes the non-lens surface of the Fresnel lens be constructed in a frosted glass-like, mat surface configuration.