Patent ID: 6309568
Filing Date: 2001-10-30
Classification: B29C,B29D,B29K,G02B

Abstract:
Production method for a lens comprising;a first step of forming thiourethane prepolymer and a second step of making the thiourethane prepolymer react with at least one urethane forming monomer, said first step and said second step being carried out in an extruder or in a reactor having an extruding device at a succeeding step,a step of extending optical thermoplastic thiourethane-urethane copolymer extruded from the extruder or the extruding device in a sheet shape,a step of forming a lens precursor by punching out the copolymer extended in the sheet shape anda step of pressing said lens precursor such that a predetermined curved face is provided at least on one face of the lens precursor.