| 摘要 |
PROBLEM TO BE SOLVED: To reduce an unnecessary detection area outside a target monitor area by changing the shape of the detection area. SOLUTION: The flame detecting device is equipped with a detecting element which converts infrared energy incident through a light-transmissive member 23 into an electric signal and outputs the resultant signal. The light-transmissive member 23 is provided with a plurality of areas 23a to 23c, each area having different transmissivity to the infrared energy. The level of the electric signal can be varied with transmissivity corresponding to the angle of incidence of the infrared energy and, for example, when large transmissivity is given to infrared energy having a 0°incidence angle, the unnecessary detection area outside the target monitor area can be reduced by reducing the detection area of the detecting element in the direction of its normal (of a detection surface). COPYRIGHT: (C)2004,JPO
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