Apparatus for measuring crystal diameter
US4794263A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1987 |
| Grant date | Dec 27, 1988 |
| Priority date | — |
| Expiry date | Oct 19, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/1012
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for measuring the diameter of a crystal in which an optical sensor scans along a sensing line which crosses at one point a luminous ring formed at the interface between a crystalline rod and a melt; the picture element position corresponding to a maximum luminance is discriminated when the optical sensor scans; the mean value of the picture element position is calculated over at least one revolution of the crystalline rod; and the diameter D of the crystalline rod at a portion thereof interfacing with the melt is calculated from the mean value and the level of the melt. Similarly, the minimum crystal diameter can be calculated by obtaining the picture element position corresponding to the minimum crystal diameter instead of obtaining the mean of the picture element position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.