| 摘要 |
<p>PURPOSE:To reduce variation in sensitivity with ambient temperature and detect gas concentration with high accuracy by forming the cross section of an infrared-ray transmission window in a wedgelike shape in an infrared-ray transmission direction. CONSTITUTION:The cross section of this invented infrared-ray transmission window 6 in the infrared-ray transmission direction is formed in the wedgelike shape. In this case, infarared light incident from, for example, a position 7 and infared light incident from a position 8 differ in transmission distance in the window, so their interference conditions are different and the window varies in transmissivity. Infrared light is made incident on the window at a variety of positions, so a detecting element 3 detects numbers of infrared rays which differ in the transmissivity of the window. Therefore, the effect of interference is reduced by cancellation and, for example, even if the window increase in thickness with the room temperature and interference conditions change, the effect of interference is reduced. Thus, variation in sensitivity with the ambient temperature is reduced and the gas concentration is detected with high accuracy.</p> |
