Temperature sensors
US5622137A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 1994 |
| Grant date | Apr 22, 1997 |
| Priority date | — |
| Expiry date | Mar 24, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K11/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A low cost, disposable temperature sensor comprising a non-porous rigid substrate having a colored patch of a contrasting color, covered by a thermochromic material which obscures the colored patch. The thermochromic material, which has a color in the visual range which completely obscures the underlying colored patch, is selected to have a melting or solidus point such that when the material is exposed to a predetermined temperature, the thermochromic material permanently changes to a relatively transparent color whereby the colored patch on the substrate is rendered visible through the thermochromic material. A transparent cover or film encapsulates the thermochromic material place on the substrate. In a preferred embodiment of the invention, the substrate comprises a paperboard product, and includes printed indicia for making a permanent record. The sensor has particular utility in measuring safe cooking temperature of food,
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.