| CPC C30B 15/06 (2013.01) [C30B 15/10 (2013.01); C30B 15/26 (2013.01); C30B 29/06 (2013.01)] | 13 Claims |

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1. An apparatus for controlling a thickness of a crystalline ribbon grown on a surface of a melt, the apparatus comprising:
a crucible configured to hold the melt;
a cold initializer configured to produce a cooling jet that is directed toward the surface of the melt;
an optical imaging device comprising a camera or a CCD camera configured to, in part, produce an image of at least a portion of the melt and the crystalline ribbon;
a processor comprising electronic circuits, logic gates, multiplexers, programmable logic devices, ASICs, analog or digital controls/switches, microcontrollers, or computing systems, the processor configured to determine, based at least in part on the image, a location of an edge of the crystalline ribbon relative to the melt surface using differences in emissivity and vibration, and to adjust a width and a thickness of the crystalline ribbon on the melt by varying a gas flow or heat of one or more of a plurality of segments based on the determined edge location; and
a segmented thinning controller that includes the plurality of segments that are each configured to output the gas flow or heat, wherein the segmented thinning controller is configured to adjust the width and the thickness of the crystalline ribbon on the melt based on signals received from the processor.
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