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Time indicator

  • US 5,058,088 A
  • Filed: 01/04/1990
  • Issued: 10/15/1991
  • Est. Priority Date: 01/04/1990
  • Status: Expired due to Term
First Claim
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1. A time indicator comprising:

  • a first substrate having first and second surfaces and at least two indicia areas on the first surface;

    a second substrate having first and second surfaces;

    a first chemical agent on each of the indicia areas;

    a second chemical agent on the first surface of the second substrate;

    wherein the first surfaces of each substrate overlay and are in contact with each other, the first and second chemical agents coacting to cause a visually perceptible change at one of the second surfaces overlaying the first indicia area in a first selected time interval and a visually perceptible change in said second surface overlaying the second indicia area in a second selected time interval, the first selected time interval differing from the second selected time interval.

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