| 摘要 |
PURPOSE:To produce the single crystal of high quality with excellent optical characteristics, by providing a shield member between a high frequency heating coil for heating the raw material of molten TiO2 and a seed crystal for drawing up single crystal and the drawn-up single crystal when the single crystal of TiO2 is produced from the molten TiO2 by Czochralski method. CONSTITUTION:Molten TiO2 1 is received in a crucible 2 and is heated by the high frequency induction heating coil 3 provided around the outer periphery of the crucible. The single crystal held with the top end of a holder 4 is submerged as a seed crystal 5 into the molten TiO2 while keeping molten state, and the single crystal of TiO2 is grown by the seed crystal 5 drawn up while rotating due to Czochralski method. In this case, the shield member 6 made of Ir or Pt-Rh alloy is provided between the heating coil 3 and the seed crystal 5 so as to be close and overlapped with the crucible 2. Thus, the single crystal of rutile (TiO2) of optical characteristics excellent in homogeneity of refractive index or double refractive index is stably grown because the seed crystal 5 and the growing TiO2 single crystal adhering to the seed crystal are not inductively heated.
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