| 摘要 |
PURPOSE:To maintain melting condition appropriately always and to grow a crystal by heating with infrared rays by measuring the diameter of a melted zone successively, by binarizing the measured values and allowing the values to be stored successively and then operating to control the quantity of electricity to be fed to an infrared ray lamp. CONSTITUTION:A line sensor 22 scans a melted zone 8 in response to clocks from a clock circuit 21 in a stage of crystal growth and outputs a signal corresponding to the dimension of the diameter of the melted zone. The output is amplified by an amplifier 23 and binarized by comparing with a referential voltage by a comparing means 24. The binarized signal is outputted to a controlling means 25. A timing pulse generator 18a generates a pulse signal for each one revolution of the melted zone 8, and the controlling means 25 stores successively the binarized measured signal. The controlling means 25 adopts the dimension of the diameter at the position of the angle of revolution corresponding to the largest rate of change, and operates basing on the measured data measured at preceding m times with the present data. The amt. of electric power to be fed to the infrared ray lamp is controlled through an electric power controller 28 basing on the result of the operation. |
