Patent ID: 6787108
Filing Date: 2004-09-07
Classification: G01N

Abstract:
A device for monitoring expiration of goods comprising:(a) a member having a surface with first and second discrete areas on said surface; (b) a first compound applied to said first discrete area, said first compound resulting in a first color when said member is at a first temperature and having the capability of changing to a second color upon reaching a second temperature higher than said first temperature, and to a third color which is irreversible upon reaching a third temperature higher than said second temperature; and (c) a second compound applied to said second discrete area, said second compound being reactive to both of (i) its thermal environment and (ii) the length of time following activation, said reactivity resulting in a color change, said color change being a single color upon reaction to one of (i) or (ii) and being multiple colors upon reaction to both (i) and (ii).