| 摘要 |
PURPOSE:To improve the detection sensitivity to an error in weight and to correctly control the diameter of a crystal by combining a means of adjusting a load detector with a means of adjusting a supporting point and a controller so as to produce a specified action and by obtaining an error in the expected amount of the crystal to be grown from the output of the load detector. CONSTITUTION:Part of the weight of a crystal 1 bears on a load detector 8 through a pulling shaft 7, and the remainder bears on a spring 9. By continuously adjusting a mechanism 15 for moving the suspending position of the spring so that all of an increase in the weight of the crystal 1 bears on the spring, the output of the detector 8 can be kept constant from beginning to end. Constant weight bears always on the detector 8 by continuously adjusting the mechanism 15 with a program regulator 17 so as to keep the output of the detector 8 at a constant value when the weight of the crystal is changed in accordance with a weight change to be estimated with respect to the desired radius of the crystal. Accordingly, when the diameter of the crystal is changed, the output of the detector 8 deviated from the constant value, and it is fed back and inputted in a heat source controller 11 to control the crystal 1 to the prescribed diameter. |
