| 摘要 |
PURPOSE:To manufacture accurately and inexpensively dies capable of coating an optical fiber without deteriorating various characteristics of the fiber by heating and working part of a heat shrinkable plastic tube to form a smaller diameter part having a desired length and by using the other parts as larger diameter parts. CONSTITUTION:A core wire 2 made of heat resistant metal, glass or the like is put in a heat shrinkable plastic tube 1 made of fluororesin, cross-linked polyolefin or the like, and an intermediate part of the tube 1 in the longitudinal direction is heated to a prescribed temp. with a heater 3. At the same time, the tube 1 is extended in the arrow directions to actively heat-shrink the intermediate part. This tube 1 is then cut to obtain 2 dies 6 each consisting of a smaller diameter part 4 having an inside diameter decided by the wire 2 and of a larger diameter part 5. By attaching the die to the outlet of a coating vessel set between a heating furnace for spinning an optical fiber and a coat curing furnace, the optical fiber can be coated desirably. |
