Non-contact method for measuring the surface temperature distribution of a melt during growth of ionic crystals
US6074087A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 1998 |
| Grant date | Jun 13, 2000 |
| Priority date | — |
| Expiry date | Mar 13, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J5/52
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The subject invention relates to a technique employing a calibrated thermal radiometer, and the radiation characteristics of ionic crystals to measure the temperature distribution of crystals during crystal growth. When in high temperature, the ionic crystals often exhibit a transparent region having low reflectance, and low absorption in the spectrum between the short-wavelength absorption edge and the long-wavelength absorption edge. In addition, these crystals have an opaque spectral region having low reflectance and high absorption, i.e. have surface radiation of high emissivity when the spectrum is in the range between the long-wavelength absorption edge and the onset of the Reststrahlen band. The spectral emissivity of the ionic crystal may not change significantly with a variation of temperature in this opaque region. According to Planck's law, the surface temperature distribution during crystal growth can be obtained after the surface radiation of the opaque region is detected, and the emissivity at the melting point is calculated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.