Capacitive humidity transducer
US4164868A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 1975 |
| Grant date | Aug 21, 1979 |
| Priority date | — |
| Expiry date | Jul 22, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/225
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive humidity transducer wherein an electrically non-conductive base carries at least a pair of electrically conductive coatings which are spaced from each other. A dielectric film which is active with respect to water absorption is also carried by the base and covers at least portions of the coatings, the dielectric film having a dielectric constant the value of which varies as a function of the extent to which water has been absorbed by the dielectric film. An outer electrically conductive, water-permeable layer is carried by the dielectric film with this film being situated at least in part between the coatings and the layer while the latter because of its water permeability permits moisture in the atmosphere to reach the dielectric film. The dielectric film maintains the outer layer permanently out of contact with at least one of the coatings, so that it is possible to measure between these coatings a capacitance which will be indicative of atmospheric humidity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.