×

Infrared measuring gauges

  • US 6,281,498 B1
  • Filed: 05/19/1999
  • Issued: 08/28/2001
  • Est. Priority Date: 11/19/1996
  • Status: Expired due to Term
First Claim
Patent Images

1. An infrared gauge for measuring a parameter of a sample, the gauge comprising:

  • a source of infrared radiation directed at the sample, a detector for detecting the amount of infrared radiation transmitted, scattered or reflected from the sample at at least one measuring wavelength and at at least one reference wavelength, wherein the parameter absorbs infrared radiation at the said at least one measuring wavelength and absorbs a lesser amount of infrared radiation at the said at least one reference wavelength, means for calculating the value of the parameter of interest from the intensity of radiation detected by the detector at the measuring and the reference wavelengths, the value of the parameter of interest being calculated according to the following equation;

    P=a0+

    ai

    f

    (Si)
    b0+

    bi

    f

    (Si)
    +c0


    where;

    P is the predicted value of the parameter concerned, for example film thickness or moisture content;

    a0, b0 and c0 are constants;

    i is 1, 2, 3 . . . and denotes the different wavelengths used;

    Si is the signal produced when the sample is exposed to a given wavelength i;

    ai and bi are constants; and

    f(Si) stands for a transformation applied to the signal Si.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×