×

Blood fluid characteristics analysis instrument

  • US 6,201,607 B1
  • Filed: 08/20/1999
  • Issued: 03/13/2001
  • Est. Priority Date: 04/13/1998
  • Status: Expired due to Fees
First Claim
Patent Images

1. A diagnostic instrument for generating a signal indicative of the level of a chemical in a body fluid sample using a reagent strip with a reagent which undergoes a color change when exposed to a fluid sample, comprising:

  • a housing having a surface for receiving reagent strips and having an optical aperture through which an optical beam from inside the housing can illuminate the reagent on the strip;

    an optical beam generating structure positioned inside the housing and producing said optical beam through said optical aperture with light from a reagent strip being reflected back through said aperture for detection;

    said optical beam generating structure further including;

    a first light source producing an optical beam directed toward said reagent strip, a reference photo detector located to detect a portion of the optical beam;

    a main photo detector located to detect reflections caused by the incidence of the optical beam onto said reagent strip;

    a control circuit coupled to said light source and said reference detector to maintain the light output from said light source substantially constant; and

    wherein said reference detector and said main detectors are so selected that a sensitivity versus wavelength characteristic of said main detector is different from a sensitivity versus wavelength characteristic of said reference detector, said reference detector being selected so that its sensitivity as a function of wavelength is sufficient to super-impose on the control circuit a compensation for changes in the wavelength of the light source and attributable to changes in the light source'"'"'s drive current or operating temperature.

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