Multi-response single layer sensor platform

An article of manufacture, comprising:

• a package;
• and
• a temperature exposure indicator on or in the package;
• the temperature exposure indicator having a mixture of a first thermochromic material and a second thermochromic material,
• the first thermochromic material having a first initial color state while in a base temperature range and configured to change to a low excursion color state below a low temperature threshold,
• the second thermochromic material having a second initial color state while in the base temperature range and configured to change to a high excursion color state above a high temperature threshold, and
• the mixture configured to have a base mixture color state in the base temperature range, a low mixture excursion color state below the low temperature threshold, and a high mixture excursion color state above the high temperature threshold,
• wherein the mixture is configured to have a third mixture excursion color state when the mixture returns to the base temperature range after having excursions both below the low temperature threshold and above the high temperature threshold, the third mixture excursion color state visibly distinguishable from the base mixture color state, the low mixture excursion color state, and the high mixture excursion color state.

A method of producing a temperature exposure indicator, comprising:

• mixing components including a first thermochromic material and a second thermochromic material to create a mixture;
• and
• applying the mixture to a substrate, producing a temperature exposure indicator including
• the substrate, and the mixture supported by the substrate;
• wherein in the temperature exposure indicator
• the first thermochromic material has a first initial color state while in a base temperature range and is configured to change to a low excursion color state below a low temperature threshold,
• the second thermochromic material has a second initial color state while in the base temperature range and is configured to change to a high excursion color state above a high temperature threshold,
• the mixture is configured to have a base mixture color state in the base temperature range, a low mixture excursion color state below the low temperature threshold, and a high mixture excursion color state above the high temperature threshold,
• wherein the first initial color state and second initial color state are colorless, white, or transparent, and the high excursion color state and low excursion color states are colored or dark.