Radiation reflection method and apparatus particularly for gauging materials exhibiting broadband absorption or scattering, or similar effects
US4085326A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 19, 1976 |
| Grant date | Apr 18, 1978 |
| Priority date | — |
| Expiry date | Oct 19, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/314
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and apparatus are provided for gauging the thickness or other property of a plastic film such as blown film or other material having a front side, a back side, and characteristics including a substantial transparency to radiation at a reference wavelength and a degree of transparency depending on the value of the property at an absorption wavelength. These methods and apparatus provide a useful measurement of the material property in the presence or absence of detrimental effects such as those caused by a broadband absorbing substance (e.g. carbon black) or scattering substance (e.g. TiO.sub.2) in the material, or variations in the apparent reflectivity of one or both of the surfaces on the front and back sides, as a result, for example, of the minute surface irregularities in high-density polyethylene. Radiations, typically infrared radiations at the reference and absorption wavelengths, are directed into the front side of the material, and reflected radiations including the reference and absorption wavelengths are detected from the front side at the specular reflection angle. From the detected radiations there is produced an instrument response wherein the effects of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.