| 摘要 |
PURPOSE:To produce a lens free from unnecessary parts by means of performing only pressing and molding in case of softening and pressing a glass material with both the upper and lower molding dies and the drum molds to mold it into the lens by providing temp. difference in the upper and lower molding dies and also using the glass material having the specified volume. CONSTITUTION:A glass material 8 for molding a lens is pressed with both the upper and lower molding dies 1, 2 and the side drum molds 3 and worked into the lens by the molding faces of the upper and lower molding dies. In this case, the glass material 8 having the following volume is put between the upper and lower molds 1, 2 and the drum molds 3, wherein as the amount of the glass material 8, the volume of a space formed with the upper and lower molding dies and the drum molds 3 is regulated to an upper limit and the volume excepted from a conventional unnecessary part is regulated to a lower limit and while heating the upper and lower dies 1, 2 with the heaters 4, 5 to heat and soften the glass material 8, this is molded into a lens 9 with the pressing due to the upper and lower molds 1, 2. In this case, the completed lens free from the unnecessary part as the lens can be formed with the pressing of one time by making the temp. of the lower mold 2 10-20 deg.C higher than the temp. of the upper mold 1, and starting the compressed deformation of the glass material 8 from the lower mold 2 and finishing it in the deformation due to the upper mold 1.
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