Wetness sensors
US9681996B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 2011 |
| Grant date | Jun 20, 2017 |
| Priority date | — |
| Expiry date | Jul 26, 2032 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61F13/42
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A wetness sensor includes a self-supporting substrate and an electrically conductive trace carried by the substrate. The trace is patterned to provide at least a portion of a tuned RF circuit, which may be disposed on only one side of the substrate and characterized by an impedance or resistance. The trace is not self-supporting. The substrate is adapted to dissolve, swell, or otherwise degrade when contacted by a target fluid. Such degradation produces a drastic change in the operation of the RF circuit, which can be interpreted by a remote reader as a “wet” condition. Contact of the substrate by the target fluid may change the impedance or resistance of the RF circuit by at least a factor of 5, 10, 100, or 1000, and/or may cause the trace to disintegrate so as to provide the RF circuit with an open circuit, and/or may substantially render the RF circuit inoperative.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.