| 摘要 |
PURPOSE:To easily produce a Fresnel plate to press-molding a transparent resin plate coated with a water soluble resin to a Fresnel shape and providing a water soluble resist only on the Fresnel slopes. CONSTITUTION:The water soluble resin 2 such as PVA is coated over the entire surface of the transparent resin plate 1 consisting of an acrylic resin or the like by using a spin coater such as whirler and a metallic mold 3 for Fresnel molding as a stripe type is heated to 120-180 deg.C and is pressurized from the coating surface of the resin 2 to mold the surface of the resin plate 1 to the Fresnel shape consisting of the Fresnel slopes 4 and Fresnel vertical faces 5. The coating layer of the water soluble resin 2 remains on the slopes 4 and th stock surface of the resin plate 1 is exposed on the vertical faces 5 as a result thereof. A light absorptive coating compd. 6 such as oily black coating compd. is then coated over the entire surface of the Fresnel faces 4, 5 and only the coating compd. 6 on the acute-angle Fresnel projecting parts 7 are wiped away and dried. The fresnel plate having the light absorptive layer 8 by the coating compd. 6 only on the vertical faces 5 is obtd. when the coating compd. 6 on the slopes is removed by dissolving the water soluble resin 2 by water or ethyl alcohol.
|
