CPC G01K 3/04 (2013.01) [G01K 11/12 (2013.01); G01K 11/18 (2013.01); G01N 21/77 (2013.01); G01N 31/22 (2013.01); G01N 31/229 (2013.01)] | 18 Claims |
1. A light-to-dark time-temperature indicator in the form of a multi-layer system, comprising:
a metal layer;
a printed layer;
an etchant layer; and
a light-diffusive layer,
wherein said metal layer has a first side facing said printed layer and a second side facing said light diffusive layer, and said etchant layer comprises an etchant that etches said metal layer when in contact therewith, said etchant layer being configured to be facing said metal layer, and
wherein said light-diffusive layer has a haze value that is constant during time-temperature progression of the time-temperature indicator.
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