Patent ID: 6884369
Filing Date: 2005-04-26
Classification: B29C,B29D,B29L,Y10S

Abstract:
1. A method of hot-forming a thermoplastic lens, the method comprising the steps of: providing a mold comprising two dies mounted in a sheath to slide along the axis of the sheath, and each presenting a transverse forming face facing the other, the two dies and the sheath being provided with intrinsic and both-way heat transfer means; placing a parison or preform of said thermoplastic material between the two dies and enclosing the assembly in the sheath; heating the dies and the sheath by their intrinsic heat transfer means up to a forming temperature; moving the dies towards each other to shape the material by plastic deformation until a predetermined relative position is reached corresponding to the thickness desired for the lens; cooling the dies and the sheath by their intrinsic heat transfer means down to an unmolding temperature; and extracting the finished lens from the mold.