The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 11, 1992
Filed:
Mar. 29, 1991
Masahiko Baba, Annaka, JP;
Hiroshi Ohtsuna, Sabae, JP;
Shin-Etsu Handotai Company, Limited, Tokyo, JP;
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.