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Thermochromic bar code

DC
  • US 6,685,094 B2
  • Filed: 12/03/1999
  • Issued: 02/03/2004
  • Est. Priority Date: 12/06/1997
  • Status: Expired due to Term
First Claim
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1. A method of producing a bar code, comprising the steps of:

  • printing bar code modules in a bar code space to define a bar code;

    wherein the step of printing the bar code modules includes printing at least one bar code module with a thermochromic material; and

    then later optically scanning the bar code to detect whether a change has occurred in the thermochromic material of the at least one bar code module after the step of printing the bar code modules to thereby determine a storage temperature history of the bar code.

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