| 摘要 |
PURPOSE:To manufacture the large size Fresnel lenses by using the bottom part mold having mirror finish mold surface and the heating elements buried near the mold surface and the upper part mold having mirror finish mold surface and the heating elements buried near the mold surface. CONSTITUTION:The mold blocks A', B', C'... as the complementary molds are united to the base 3 and compose the bottom part mold 4. The mold surfaces a, b, c... are polished to mirror finish and the heating elements 5 are buried near the mold surface. The upper part mold 6 is made of planar glass and its mold surface is polished to mirror finish and the heating elements 8 are buried near the mold surface. A gasket 9 exists between the bottom part mold and the upper part mold and the thickness of the lenses is determined by the height of the gasket. The molded resin is made in the large size lenses shown in the figure. |
