| 摘要 |
In making composite reflective elements consisting of a principal transparent body which receives and refracts light so that it is focused through a spherical surface onto a reflecting surface, the transparent body is coated with a transparent layer of plastic capable of remaining soft at a low temp. but gelling rapidly at 100 degrees C and is treated with small balls preheated to 100 degrees C. which initiate local gelling so that when the surface is completely covered the resin has polymerised. The method is suitable for forming spherical surfaces with a coating of small balls, or by detaching them, surfaces backed with spherical imprints which can be reflectively coated. The principal transparent body is pref. a sphere of a lenticular shape. The plastic coating layer is pref. a polyisocyanate mixed with a polyester contg. free OH gps. together with an amine accelerator. The small balls may be precoated with a release agent. After removal of the balls the spherical imprints may be coated with a reflective layer out may also first receive a meniscus of solidified liquid resin. |
