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DIGITAL THERMOMETER AND METHOD OF MANUFACTURE

  • US 3,861,213 A
  • Filed: 04/16/1973
  • Issued: 01/21/1975
  • Est. Priority Date: 06/15/1972
  • Status: Expired due to Term
First Claim
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1. A digital thermometer readable by comparing the intensity of the visibility of the adjacent digits comprising:

  • a flat support having a plurality of digital representations lineally disposed in a predetermined order of increasing value, said digits being delineated by transparent areas and cooperating opaque areas;

    a plurality of different microencapsulated liquid crystal compositions having different temperature response ranges substantially uniformly coated in substantially parallel bands over the combination of said transparent areas and cooperating opaque areas, said bands having a preselected approximately equal thickness, each of said coated liquid crystal compositions having a lower transition temperature below the numerical value represented by its digital representation and having an upper transition temperature above the numerical value represented by its digital representation, each coated liquid crystal composition having a temperature response range overlapping the temperature response range of the liquid crystal composition coated onto the transparent area of the next succeeding numerical value, the amount of overlap between adjacent digital representations being sufficiently consistent and of a magnitude so that the relative intensity of adjacent digits can be compared to estimate temperature.

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