Method and apparatus for measuring the opacity of sheet material
US4380396A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1980 |
| Grant date | Apr 19, 1983 |
| Priority date | — |
| Expiry date | Dec 29, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/86
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
To measure the opacity of sheet material, such as paper, a beam of light is directed against the material and the intensity of any light passing through the material is sensed and converted to a visual readout. A plurality of opacity measurements are made at different areas on the sheet material and, when a selected number of measurements have been made, a readout of the average value of the measurements is generated. The particular technique enables a large number of opacity measurements to be quickly and conveniently made and averaged, and is considerably less complicated and time consuming than opacity measurements which are conventionally made as a function of contrast ratios.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.