| US 7,524,463 B2 | ||
| Heated volatile dispensing device with dye-based use-up indicator | ||
| Joel E. Adair, Racine, Wis. (US); Brian T. Davis, Burlington, Wis. (US); Gopal P. Ananth, Racine, Wis. (US); and Padma Prabodh Varanasi, Racine, Wis. (US) | ||
| Assigned to S.C. Johnson & Son, Inc., Racine, Wis. (US) | ||
| Filed on Feb. 03, 2006, as Appl. No. 11/346,752. | ||
| Prior Publication US 2007/0181707 A1, Aug. 09, 2007 | ||
| Int. Cl. A62B 7/08 (2006.01); A24F 25/00 (2006.01) | ||
| U.S. Cl. 422—125 [239/53] | 16 Claims |
| 1. A substrate capable of dispensing a volatile air treatment chemical upon heating of the substrate in its configuration
at a selected use temperature, the substrate comprising:
said volatile air treatment chemical;
a use indicator associated with the substrate and configured to automatically communicate an extent to which the air treatment
chemical has been dispensed from the substrate as the substrate is heated at the selected use temperature, the use indicator
comprising:
at least two dyes each having an at least somewhat different color from the other; and
a covering configured to restrict migration of the dyes prior to heating of the covering, and to permit migration of the dyes
while the substrate is being heated;
wherein upon a first extent of heating of the substrate at the selected use temperature, a first of said two dyes can at least
in part migrate to a first visible position and be visible;
wherein upon a second extent of heating of the substrate at the selected use temperature after the first extent of heating
a second of said two dyes can at least in part migrate to a second visible position that is the same or different from the
first visible position so as to be visible; and
wherein the extent to which the two dyes become visible in this manner is indicative of the extent to which the air treatment
chemical has been dispensed from the substrate.
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