| 摘要 |
PURPOSE:To grow automatically and stably a crystal for many hours by providing a filter and a diaphragm to an optical system in the titled apparatus for automatically controlling by the observation of an image of the melt zone from the port of a spheroidal mirror. CONSTITUTION:The image of a melt zone is focused on an optical sensor from the port provided at a part of a spheroidal mirror through an optical system consisting of a lens, a prism, a half mirror, a reflector, etc., and the diameter or the external shape of the melt zone is fed back to the lamp power or the height of the melt zone to control automatically in the titled apparatus. In the apparatus, the optical system is constituted of a melt zone 41, a filter 42, a lens 43 (including a prism), a diaphragm 44, an optical sensor 45, and a front panel 46. When the luminance of the melt zone is changed because the required power is varied in accordance with the kind of materials of the crystal, the change can be coped with by the exchange of filters and the opening degree of the diaphragm. Consequently, the crystal can be stably grown for many hours (>=10hr).
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