Long term rapid color changing time indicator
US5633835A · kind A · utility
71Cited by
14References
24Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1994 |
| Grant date | May 27, 1997 |
| Priority date | — |
| Expiry date | Feb 10, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09F3/207
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A time indicator that rapidly changes color after a specific time interval is provided. The time indicator includes a base substrate with colored dye deposited on a first surface; a barrier applied over the colored dye; and a substrate having an adhesive on a first surface thereof. The substrate and the base substrate are put into adhesive contact. The adhesive coacts with the barrier to dissolve the barrier in a specified time interval. The adhesive then contacts the colored dye to dissolve the dye and permit the dye to migrate through the adhesive to cause a color change visible through the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.