Patent ID: 8267576

Claim:
A time-temperature indicator device comprising (i) at least one active reactant being at least a part of an electrical component, said at least one active reactant is selected such that it changes at least an electrical property of said at least a part of said electrical component at a rate that is temperature dependent or time-temperature dependent, wherein the active reactant is a metal or an oxide thereof, or a semiconductor, and (ii) at least a first passive reactant in the form of a viscous substance; wherein said viscous substance is in contact with said active reactant, such that said at least one active reactant reacts with said at least a first passive reactant to induce temperature dependent or time-temperature dependent disintegration of said active reactant, wherein said at least a first passive reactant and said active reactant are selected such that they cause temperature dependent or time-temperature dependent development of said temperature dependent or time-temperature dependent disintegration, thereby effecting a change in at least an electrical property of said at least a part of an electrical component at a rate that is temperature dependent or time-temperature dependent; wherein said change in at least an electrical property of said at least a part of an electrical component is associated with a change in a visual physical property of the indicator device.