| 摘要 |
A gas sensor 1 comprises an electromagnetic radiation source, located within a light source cavity 10, a detector, located within a detector cavity 12, which is sensitive to radiation from the source and a waveguide which comprises at least a part of an optical path from the source to the detector through a gas sample, the waveguide comprising a first waveguide portion 14 which extends from the radiation source and a reflector 16 which is arranged to change the direction of and laterally displace radiation conducted from the source through the first waveguide portion into a second waveguide portion 18 which is separate to the first waveguide portion and which conducts received radiation towards the detector. The gas sensor can be formed as a layered structure including body portions which define co-operating formations, such as recesses (24, figure 2) and raised portions (26, figure 5), which resist the penetration of external electromagnetic radiation into a gas sample volume within the sensor. A convoluted passage comprising one or more bends allows gas access to the optical path without providing a direct light path through the passage. |
