| 摘要 |
PROBLEM TO BE SOLVED: To provide a preform for precise press molding and a method for producing an optical element using the preform for precise press molding. SOLUTION: A glass preform for precise press molding has a rotation symmetric axis, two end faces crossing the rotation symmetric axis respectively and a side face connected to the outer peripheries of the two end faces. The two end faces are faces to be pressed, are independently a convex surface or a concave surface, have an axis coinciding with the rotation symmetric axis and have a ratio (ϕ/h) of a diameter ϕ to the height h of a column of 1 or more and 3 or less and a ratio (V/V<SB>0</SB>) of the volume V of the preform to the volume V<SB>0</SB>of the column of 68% or more when an imaginary column circumscribing the preform is assumed. The method for producing the optical element comprises precisely press-molding the preform for precise press molding by using a press molding die. COPYRIGHT: (C)2009,JPO&INPIT
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