Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1991-03-29
1992-08-11
Anderson, Bruce C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250577, 156601, G01N 2186, G01V 904
Patent
active
051381796
ABSTRACT:
Disclosed are a method of and a device for crystal diameter measurement in an apparatus for automatically controlling single crystal growth by the CZ technique. In the diameter measurement method, a growing region of a single crystal 32 is photographed by a camera 38, and an outer diamter Do of a luminous ring image 70 having a luminance above a reference value E is detected from a video signal supplied from the camera 38, the diameter Do thus detected being used for crystal diameter control. The crystal diameter measuring device comprises: a camera 38 for photographing a growing section of a single crystal 32 and supplying a video signal; devices for detecting a maximum video signal value with respect to one scanning line or more; a device for obtaining a reference value E corresponding to the above-mentioned maximum value; devices for binary-coding the video signal in comparison with the reference value E; and a device for detecting the outer diameter Do of a luminous image from a binary image obtained by the binary-coding.
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Baba Masahiko
Ohtsuna Hiroshi
Anderson Bruce C.
Shin-Etsu Handotai Company Limited
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