| 摘要 |
PURPOSE:To enable the simultaneous forming of a plurality of optical elements having little fluctuation of optical performance by using a forming mold having a body mold integrated with an intermediate mold and forming the element while adjusting the pressured and the sliding length. CONSTITUTION:A glass raw material is heated to a temperature near the softening point with a heater above an upper mod 11, a heater under a lower mold 12 and hot air blasted against the lateral side of an intermediate mold 13. Thereafter, the material is pressed with the upper mold 11 and the lower mold 12 and deformed into a sphere. The pressure is maintained at a definite level during the heating and pressing step and the sliding length is maintained to a constant state in the cooling and pressurizing step to enable the simultaneous forming of a plurality of optical elements. In the above process, clearances of several mum are given to the circularity of the outer flange diameter of the upper mold 11 and the outer diameter of the cylinder, the circularity of the outer diameter of the flange of the lower mold 12 and the outer diameter of the cylinder part and the circularity of the outer cylindrical surface 23 and the inner cylindrical surface 24 of the intermediate mold 13. The molds can be slid while maintaining the alignment of the center line of the upper mold 11 and the intermediate mold and that of the lower mold 12 and the intermediate mold 13. |
