| 摘要 |
PROBLEM TO BE SOLVED: To keep the sectional form of a gasket constant to a mold used for the precision molding of the concave surface of a plastic lens for glasses to an aspheric surface such as a hyperboloidal surface, elliposoidal surface or the like and/or a toroidal surface. SOLUTION: At the peripheral part of a mold 1, 2 for molding a concave surface, a surface A, against which a gasket 3 is abutted, is so constituted as to lie in the same plane and, by changing the height (h) of the surface B, the height H of a portion serving as the roll of the spacer of the gasket 3 is made to be constant. Further, by providing at least two adjoining surfaces to the surface A, the airtightness between the gasket 3 and the mold 1, 2 is improved. |
