| 摘要 |
PROBLEM TO BE SOLVED: To set the difference between the collar widths of a far distance use part and a near distance use part within the range of a tolerable value by molding a glass optical element through softening the element using a master mold having the near distance use and the far distance use part and bringing a molding glass mold into contact with a polishing face while an offset load is imparted to the near distance use part and further, forming a collar face orthogonal with an optical axis on the peripheral edge of the glass mold. SOLUTION: A planar circular glass mold 12 is molded using a master mold and a press mold and after removing a transfer mark or performing any other process, the near distance use part side is retained in the recessed part 50a of a glass mold holder 50 so that the near distance use part side is located below the pressure center part 50b. The glass mold 12 retained by the glass mold holder 50 is placed on the polishing tray 43 of a polishing machine 40 and an eccentric shaft 23 of a glass mold rotary mechanism 30 is fitted into the pressure center part 50b. Further, a diamond sheet with a specified grain coarseness is previously bonded to the polishing tray 43 of the polishing machine 40 and the tray 43 is eccentrically rotated to polish the peripheral edge part of the near distance use part side much more than the peripheral edge part of the far distance use part side. Thus it is possible to mold the collars of the far distance use part side and the near distance use part side to the specified width. Consequently, the collar widths of both distance use parts of the glass mold 12 within the tolerable value. |
