초록 ▼

The absorption of laser radiation by a gas (such as oxygen and/or carbon dioxide) in human breath is detected on-airway by generating laser radiation using a laser diode, passing the laser radiation through a volume containing human breath multiple times, and detecting the laser radiation which is n

The absorption of laser radiation by a gas (such as oxygen and/or carbon dioxide) in human breath is detected on-airway by generating laser radiation using a laser diode, passing the laser radiation through a volume containing human breath multiple times, and detecting the laser radiation which is not absorbed by gases in the volume. To reduce the amount of energy required to control the laser diode, a laser diode is selected which generates laser radiation having a wavelength which is reasonably close to the wavelength of an absorption line of a desired gas when the laser diode is at or near normal body temperature. By passing the laser radiation through the sample gas multiple times, a longer path through the sample gas is provided for absorption thereby allowing the concentration of a gas having weak absorption lines (such as oxygen) to be determined using on-airway absorption detection. A two piece on-airway spectroscopy device is disclosed having a disposable mouthpiece portion and a reusable sensor assembly portion having a laser diode and a photodetector.

대표청구항 ▼

An absorption spectroscopy device, comprising: a hollow mouthpiece member defining a sample cell, human breath being present in said sample cell; a photodetector; a laser diode, laser radiation emitted from said laser diode passing through said human breath in said sample cell and being incident on

An absorption spectroscopy device, comprising: a hollow mouthpiece member defining a sample cell, human breath being present in said sample cell; a photodetector; a laser diode, laser radiation emitted from said laser diode passing through said human breath in said sample cell and being incident on said photodetector, said laser radiation reflecting off a reflective surface in its path between said laser diode and said photodetector; and means for controlling said laser diode to lock onto a single absorption line of a gas in said human breath in said sample cell without passing laser radiation through a reference cell and to a second photodetector.