| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical gas sensor, requiring no explosion-proof countermeasures, and accurately detecting the concentration of gas in a means for optically measuring the concentration of the gas. SOLUTION: A modulated laser beam is oscillated from a laser beam source 21s, using the laser beam source 21s and the intensity of transmitted beam or reflected beam, obtained through a gas atmosphere to be measured is detected, and the concentration of the gas is detected from a signal obtained by the phase-sensitive detection of specific frequency components in the detected signal. In this optical gas sensor 1, a measurement element 10, reacting with the gas to be transformed, is provided to the sensor head 8, installed in the gas atmosphere and the transmitted or reflected light from the measuring element 10 is detected by a monitor photodetector 2 and the specific frequency components of the reflected light, in the electrical signal outputted from the monitor photodetector 2, are subjected to phase-sensitive detection by the measurement part 11. COPYRIGHT: (C)2006,JPO&NCIPI
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