PARTICLE DETECTION SENSOR, DUST SENSOR, SMOKE DETECTOR, AIR PURIFIER, VENTILATION FAN, AND AIR CONDITIONER

摘要

A particle detection sensor includes: a light projection system (120) that outputs and focuses light on a detection area (DA); a light reception system (130) that receives scattered light, which is light from the light projection system (120) that has been scattered by a particle (2) in the detection area (DA); and a light trap (50A) disposed across the detection area (DA) from the light reception system (130). The light trap (50A) includes: a closed space (51A) having an opening (52A) that opens toward the detection area (DA); and a plurality of wedge-shaped protrusions (115) disposed in the closed space (51A). The plurality of wedge-shaped protrusions (115) each include a base and a tip nd. Among the plurality of wedge-shaped protrusions (115), the farther a wedge-shaped protrusion (115) is located from the detection area (DA), the less a distance between the base and the tip end of the wedge-shaped protrusion is.