| 摘要 |
PURPOSE:To prepare a high-purity preform readily, by rotating a cylindrical core material around its axis center and depositing a cladding material on its side face while transferring the core material in the direction of the axis center. CONSTITUTION:The cylindrical high-purity core material 3 is supported by the retaining part 5 fixed to the shaft 4 readily reciprocating. The root part 3' of the core material 3 is placed at a place near the through hole 7. The valve 9 is opened, the cladding material 15 is evaporated by the heater H while vacuum is applied in direction of the arrow (q), and the shaft 4 is transferred in the direction of the arrow P' with its rotation. The cladding material enters through the communicating path 9 and the through hole 7 to the vacuum chamber 6 and is deposited from the root part 3' of the core material 3 to the front end part 3'' successively. After deposition, the shaft 4 is transferred in the direction of the arrow (p), to return the core material to the original position. Similarly, the valves 10 and 11 are opened successively, and the cladding materials 16 and 17 are deposited on the outer side surface of the cladding material 15 successively. Therefore, a metal halide can also be deposited redily in high purity. |
