Patent ID: 6411391
Filing Date: 2002-06-25
Classification: C30B

Abstract:
A method of measuring a crystal section shape of a crystal being pulled from a crystal melt while rotating, comprising:taking an image of a base of the crystal in horizontal and vertical directions with a two-dimensional camera set at an upper oblique position over the crystal; setting at least two horizontal light measuring lines in the image taken by the two-dimensional camera, said at least two horizontal light measuring lines being arranged in parallel in the vertical direction; detecting pairs of intersection points at which a fusion ring intersects said at least two horizontal light measuring lines; combining the pair of the intersection points obtained on each light measuring line to interpolate the space between measurement pitches, determined by the camera response speed and rotational speed; and determining diameters of said crystal based on combining and on a time lag between two intersection points of each of said pairs of intersection points.