| 摘要 |
PURPOSE:In molding an optical element by molding method under pressure, to obtain freely an optical element in a desired shape by a simple method using a parallel flat material, by setting grooves on the material before it is molded under pressure. CONSTITUTION:Before a material is molded between the top mold 1 and the bottom mold 2, the grooves 6 (four in the figure) are formed on the peripheral surface of the material 5. The grooves 6 extend at one side of the material and the opposite side in the direction wherein pressure is applied to a mold cavity. When the material 5 thus constructed is put between the molds 1 and 2, pressed and transformed, air existing in the space 4 between the material 5 and the mold 2 is released in the arrow 7 direction and is not closed in it. Since the material constituting the grooves 6 are transformed outward with the transformation of the material 5, parts corresponding to the grooves 6 of the material 5 are transformed until they are shown by the broken lines 8 and the grooves 6 are eliminated when the optical element 9 in a desired shape is molded.
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