Sensing of material of construction and color of containers
US4919534A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1988 |
| Grant date | Apr 24, 1990 |
| Priority date | — |
| Expiry date | Sep 30, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/25
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and process permit the material of construction and the color of transparent and partly transparent containers to be determined rapidly and accurately. To determine the material of construction, polarized light is passed through the container, portions of the transmitted beam are analyzed by parallel and cross polarizers, the intensities of the analyzed beams are measured, and the sum and difference of the analyzed beams are determined. Preferably, the determination is made with at least two wavelengths of polarized light, and the sums and differences of the intensities of the different wavelengths are determined. Glass containers do not alter the polarization of the transmitted light, while many types of plastic containers do alter the polarization, and this difference serves as the basis for the differentiation. The color of the container, whether it be glass or plastic, is determined by calculating a color index as the difference in the transmitted intensity for light of different wavelengths, and this difference, particularly when normalized by the sum of the transmitted intensities, serves as a color index for characterizing the color of the container. An automate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.