| 摘要 |
PURPOSE:To efficiently obtain the titled base material with high deposition efficiency by depositing fine glass particles formed by passing a gaseous raw material through a flame to the outside periphery of a starting material and ejecting gaseous He to the deposited part thereof, thereby cooling said part. CONSTITUTION:Both ends of the starting member 3 are mounted rotatably at a prescribed rotating speed by means of chucks. A burner 1 is disposed above a stand which moves back and forth in the axial direction of said member. A gaseous He injection nozzle 5 is also disposed in the position opposite 180 deg. from the burner 1 with the axis in-between. While the member 3 is kept rotated at the prescribed rotating speed, gaseous H2, O2, SiCl4 and Ar are supplied to the burner and the SiCl4 is cracked in the combustion flame 2 to form the fine glass particles which are deposited on the member 3. The gaseous He is simultaneously injected from the nozzle 5 to cool the deposited glass. The deposited part A under cooling is moved to the flame 2 side and the fine glass particles are deposited thereon as the member 3 rotates. The burner 1 and the nozzle 5 are successively moved and a porous preform 4 which is a base material is thus formed. |
