Smoke sensor

Abstract

To prevent first irradiation light from directly reaching a light receiving element from a first light emitting element in a smoke detector, which includes: the light receiving element, the first light emitting element whose forward scattering is received by the light receiving element; and a second light emitting element whose backward scattering is received by the light receiving element.SOLUTION: A smoke detector includes: a smoke detection part surrounded by a peripheral wall from the lateral side; and a first light emitting element, a second light emitting element, and a light receiving element arranged in the periphery of the smoke detection part. The light receiving element and the first light emitting element are arranged so as to allow the light receiving element to receive forward scattering light formed when first irradiation light transmitted from the first light emitting element is applied to smoke in the smoke detection part. The smoke detector also includes a light shielding plate which is arranged between a first optical axis being the optical axis of the first light emitting element and a second optical axis being the optical axis of the second light emitting element, which has a plane along a direction in which the second light emitting element is oriented.SELECTED DRAWING: Figure 3

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