| 摘要 |
PURPOSE:To mold a plastic lens having a large deflection of wall thickness by making degassing holes on a barrel mold that is mounted on a lower mold for supporting a lens material. CONSTITUTION:A plastic material 8 of PMMA formed into a panel is inserted into a space defined by a lower mold 5 and a barrel mold 7 so as to be mounted on the molding surface of the lower mold 5 and, when the upper mold 4, lower mold 5, barrel mold 7, and the material 8 are heated by electrifying a heater 2, the material 8 is heat-softened and results in covering the molding surface 5a of the lower mold 5. At this time, air existing in the space between the material 8 and the molding surface 5a is discharged from a degassing hole 7a made on the barrel 7, so that the material 8 comes into close contact with the molding surface 5a. Following this, the upper mold 4 is lowered by a pressing rod 6 for press-molding the material 8. In this case, since air existing between the material 8 and the molding surface 4a of the upper mold 4 is discharged from the degassing hold 7a, the molding surface 4a and material 8 come into close contact with each other. And, after electrification to the heater 2 is stopped and the material 8 is cool-softened, the upper mold 4 is raised for removing an optical element. Whereby, in use of a plastic material having a small deflection of wall thickness, an optical element with an excellent transferring property can be molded. |
