Method of selecting an optical filter for a shutterless opticall

Details Method of selecting an optical filter for a shutterless opticall Method of selecting an optical filter for a shutterless opticall

1991-10-28

1994-01-25

Howell, Kyle L.

Radiant energy

Invisible radiant energy responsive electric signalling

Infrared responsive

G01N 2161, G01J 351

Patent

active

052818179

ABSTRACT:
Methods and apparatus for constructing optically stabilized, shutterless infrared capnographs are disclosed. The capnographs of the present invention provide the absolute concentration of the constituents of the respiratory airstream of a patient, without the thermal drift problems normally associated with thermopile detectors, thereby providing a device with a high degree of accuracy. The present invention eliminates the need for a mechanical shutter to modulate the incident infrared beam and the need for a modulated source, thereby increasing the reliability and response time of the devices disclosed. Capnographs which are substantially unaffected by changes in the ambient temperature at which they operate are provided by connecting pairs of optically filtered thermopiles in series and processing the resulting differential pair. In addition, techniques are provided for selecting overlapping optical filters for use with thermopiles with a minimum level of cross-talk. A processing technique is also given which allows the concentrations of two or more airstream constituents to be separately quantified even when such overlapping optical filters are used.

REFERENCES:
patent: 3539804 (1970-11-01), Billetdeaux et al.
patent: 3745349 (1973-07-01), Liston
patent: 4423739 (1984-02-01), Passaro et al.
patent: 4648396 (1987-03-01), Raemer
patent: 4772790 (1988-09-01), Aldridge
patent: 4914719 (1990-04-01), Conlon et al.
patent: 5046018 (1991-09-01), Flewelling et al.
patent: 5130544 (1992-07-01), Nilsson
Severinghaus et al., "Correction Factors for Infrared Carbon Dioxide Pressure Broadening by Nitrogen, Nitrous Oxide and Cyclopropane", Anesthesiology, May-Jun. 1961, pp. 429-432.
Haaland, D. M., "Methods to Include Beer's Law Nonlinearities in Quantitative Spectral Analysis", Computerized Quantitative Infrared Analysis, ASTM STP 934, G. L. McClure, Ed., ASTM, Phila. 1987, pp. 78-94.

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