MANUFACTURE OF PLASTIC LENS AND APPARATUS THEREFOR

PURPOSE:To improve the productivity and accuracy of a lens by injecting a liquid plastic raw material, which is hardened by heat, into a lens forming cavity defined by a pair of molds, and hardening it into a predetermined lens shape while heating and pressing the raw material by the molds. CONSTITUTION:A lens molding cavity is defined by molds 2a, 2b and sealed by a packing 3. Into the molding cavity 6, a liquid resin raw martial monomer 1 is injected that is added by a polymerization initiator. By raising the tempera ture of molds 2a, 2b, the liquid resin raw material monomer starts reacting and, by the spring force of pressing springs 4, the molds 2a, 2b are urged in the proximity direction so that the liquid resin raw material monomer 1 is pressed therein. By heating, the liquid resin raw material monomer 2 comes into polymerization so as to be hardened and contracted, however, it is in a state of being pressed by the springs and the package 3 is subjected to deforma tion, whereby the molding cavity 6 is configured into a predetermined lens shape by following the hardening an contraction of the liquid resin raw material 1.