| 摘要 |
PURPOSE:To obtain a high-accuracy polyhedral mirror, by forming a plastic layer on the side face of a polygonal metal core and then evaporating a metallic film on the surface of the plastic layer. CONSTITUTION:The thin plastic layer 2 is formed at the side face area of a polygonal plate type core 1 made of metal which becomes the center part of a polyhedral mirror by an injection molding, a casting and other methods. Furthermore, a metal such as alluminum or the like a vacuum-evaporated on the surface of the layer 2 to obtain a mirror surface. In this case, the core 1 uses the alluminum cut with the diagonal length (x) of 28mm. and the thickness of 8mm. for example. On the other hand, the mirror surface part 2 is formed by producing the methyl methacrylate resin by an injection moldig and with use of a metal mold having a coarseness of 0.05S on the surface of evaporation and then evaporating the SiO by 30-80Angstrom on the resin surface after a vacuum evaporation of alluminum by 2,000Angstrom . In such way, the side face accuracy of the metallic core 1 can be eased greatly to obtain a polyhedral mirror that has a substantially equal quality to the conventional product. |
