×

Long term rapid color changing time indicator

  • US 5,602,804 A
  • Filed: 08/03/1995
  • Issued: 02/11/1997
  • Est. Priority Date: 08/03/1995
  • Status: Expired due to Fees
First Claim
Patent Images

1. A time indicator comprising:

  • a display layer having a defined display region therein;

    a migration layer overlying and attached to the display layer, the migration layer having a migration region therein, the migration region in contact with the display region at a display region contact area;

    an activation layer having a defined activation region therein, wherein the activation region includes a migrating agent capable of migrating laterally through the migration region, wherein when the activation layer overlies the migration layer, the activation region overlies the migration region, the migration region connecting the activation region with the display region which is laterally distal from the activation region at the display region contact area;

    adhesive means associated with the activation layer or migration layer for adhesively attaching the activation layer to the migration layer;

    whereby when the activation layer is contacted with and overlies the migration layer, the adhesive means adhesively attaches the activation layer to the migration layer causing the activation region to contact the migration region, wherein the migrating agent is activated to migrate laterally from the activation region through the migrating region to the display region contact area in contact with the display region in a predetermined amount of time to cause an indication in the display region that the predetermined amount of time has elapsed.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×