Method of and device for diameter measurement used in automatically controlled crystal growth
US5138179A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1991 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Mar 29, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/08
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.