Mold and a method of hot-forming a thermoplastic lens

A method of hot-forming a thermoplastic lens, the method comprising the steps of:

• providing a hot-forming mold comprising two opposing dies mounted in a sheath that slide along an axis of the sheath, each of the two dies presenting a transverse forming face facing the other, the two dies and the sheath each having a respective intrinsic and both-way heat transfer device;
• placing a preformed thermoplastic material between the two dies and then enclosing the material in the sheath;
• then, heating the two dies and the sheath by the respective intrinsic heat transfer device 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 a finished lens;
• cooling the dies and the sheath by the respective intrinsic heat transfer device down to an unmolding temperature;
• and
• extracting the finished lens from the mold.