Method of manufacturing plastic optical transmission medium

摘要

PCT No. PCT/JP93/01148 Sec. 371 Date Apr. 14, 1994 Sec. 102(e) Date Apr. 14, 1994 PCT Filed Aug. 16, 1993 PCT Pub. No. WO94/04949 PCT Pub. Date Mar. 3, 1994A polymer is placed and heated within a cylinder 1. Then the polymer is subjected to a pressure and extruded in the form of fibers from a nozzle 3. When a diffusible material is injected from a nozzle 5 through a capillary cylinder 4 into the central portion of the polymer melt, the diffusible material gradually diffuses from the central portion toward the peripheral portion while flowing toward the injection port of the nozzle 3. The material extruded from the nozzle 3 is cooled by air and wound on a drum 7 through a roller 6. Fiber-like molded product has a distribution of refractive index which continuously varies from the central portion toward the periphery portion to result in a light-converging or light-diverging plastic optical transmission medium. Reversely, even though the polymer melt is extruded from the nozzle 5, there can be obtained an optical transmission medium also having a region where the refractive index continuously varies. A variety of selections are possible for the number of cylinders and the material to be supplied into the cylinder.