PURPOSE: To set S/N of the output of a detecting body to ≥10dB even if a temperature difference of the inside and the outside of a visual field range, by setting an infrared ray which is made incident on an infrared detector, to transmission and non- transmission states alternately, by a pair of vibrating bodies and opposed bodies, and setting the maximum incident angle to ≤90°.
CONSTITUTION: A position relation of opposed bodies 10, 11 is varied periodically by a periodical vibration in the reverse direction of vibrating bodies 8, 9, and a state that a slit 12 is superposed on each other and opened or closed in repeated. An infrared ray which is made incident on an infrared detecting body 6 from an opening 3 is varied periodically, and a signal corresponding to a difference between a temperature of a part whose temperature is measured and a temperature of the opposed body is outputted. When the maximum incident angle θ is set to ≤90°, and a temperature of an object to be detected, within a visual field range, and a temperature of the outside of the visual field range are 0°C and 100°C, respectively, an energy ratio of both of them goes to about 9%, and S/N of the output of the detecting body 6 goes to 21dB. Accordingly, even if a temperature difference of a heat source between the inside of the visual field range and the outside of the range is large, the S/N can be set to ≥10dB.
TSUJI MASATO
IKEDA MASAMI
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