Abstract: A calibration method and a calibration device for two-point cold calibration are suitable for calibration of any visual measuring system having a width analyzer. In particular, the method and the calibration device are used to calibrate a CCD camera in a visual measuring system used to monitor the diameter of a crystal rod being grown by a crystal growing apparatus using the well-known Czochralski process. The calibration method takes into account non-linear error and avoids the need to actually grow crystals for calibration. The calibration device is specifically designed for quick and accurate set-up.

Abstract: A system for measuring the rotational speed of a shaft driven by a motor. The system includes a rotation measurement device having a rotatable sensor and configured to generate a signal corresponding to rotation of the sensor. The rotation measurement device may be supported by a fixture mountable on the motor. A coupler is associated with the sensor and includes a gripping surface configured to contact and grip the end-surface of the shaft to couple the sensor to the shaft and impart the rotation of the shaft to the sensor.

Abstract: A level detector detects the level of an approximately flat surface of a substance in a container. The level detector illuminates a portion of the surface, and detects the location of the illuminated portion on the surface. Based on detecting the location of the illuminated portion, the level detector generates a signal related to the level of the surface, which can represent the level of the surface in a direction perpendicular to the surface. A method for determining a level of a surface of a substance in a container includes illuminating a portion of the surface, detecting a location of the illuminated portion on the surface, and generating a signal related to the level of the surface based on the result of detecting the location of the illuminated portion.

Abstract: A CCD camera is used to measure the diameter of a growing crystal through optical recognition of the luminous ring at a crystal-melt interface. The result is an optical diameter control method and apparatus that eliminates the negative effects of orbit, melt-level and incorrect camera angle. The CCD camera is positioned such that it focuses on a full half of the circumference of the crystal as it is being grown. An automatic control system uses two points diametrically opposed on the crystal to measure the diameter, and a third point on the crystal closest to the camera to compute the melt level error. The automatic control system controls a crucible height and a crystal pull rate to optimize crystal diameter.