VARIABLE ROTATION TYPE FLOPPY DISK DEVICE

摘要

PURPOSE:The average diameters of the single crystal are compared with the standard values every unit time to detect their deviation and the heating of the crucible is controlled by the signals of power deviation and the program signals to produce a single crystal with a desired shape in high reproducibility and yield in a short time. CONSTITUTION:The detecting signals from the weight detector 19 through the AD converter 21 and the signals from the pulling-up distance detector 20 are sent to the central processing unit 23. The unit 23 calculates the average diameter of the formed crystal every unit time on the basis of these signals. The calculated diameters are compared with the standard values of the diameters corresponding the pulling-up distance to obtain the deviation and the values are sent to the DA converter 24 into correction signal Fc. In the meantime, the reading signals Fr from the heating program curve for the heater 12 are given every unit time to the program signal generator 25 from where the program signals Fp are read out. Corrected program signals Fcp are obtained from signals Fc and Fp through the controlling circuit 26 and the heater 12 is controlled in heating by the power controlling signals Pc obtained through the high-frequency oscillator 13.