| 摘要 |
PURPOSE:To raise the measuring accuracy and to improve a following-up property, by detecting only a component of a heat radiation spectrum having a shorter wavelength than the wavelength corresponding to the maximum spectral emmisivity of radiation of a black body at the melting point of a material having the high melting point. CONSTITUTION:A crucible 3 made of quartz and graphite is heated with a heater 4 and a silicon crystal 1 is pulled up from a silicon melt 2. Heat radiation from the melt 2 is detected by an electromotive force element 12 through an optical filter 11 and the temperatue detected by the element 12 is fed back to the heater 4 by an electric power supply controlling circuit 8 and then, the temperature of the melt is controlled constant. The filter 11 passing through a wavelength corresponding to the maximum spectral emissivity at 1,410 deg.C, the melting point of silicon, that is, a component having shorter wavelength than 520nm, is used. In this manner, the temperature is measured with good responsing property in high accuracy by performing the temperature measurement from the wavelength component having a high signal noise ratio and also having the sharp radiation intensity for the temperature change. |
