Patent ID: 11915569
Assignee: NOHMI BOSAI LTD.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. The smoke detector according to claim 1, wherein:
a second light-emitting element is disposed in a position in which the light-receiving element receives backward-scattered light produced when smoke in the smoke detection part is irradiated with second irradiation light emitted from the second light-emitting element;
the peripheral wall includes a primary reflection region from which the second irradiation light emitted from the second light-emitting element is reflected when the smoke detection part without smoke is irradiated with the second irradiation light, the primary reflection region being a deflective reflecting wall configured to reflect the second irradiation light in a direction different from the direction in which the second irradiation light enters;
the light-receiving element is accommodated in a light-receiving element accommodation wall projecting inside the peripheral wall; and
the second irradiation light reflects from the deflective reflecting wall, and is guided to a side of the light-receiving element accommodation wall which is opposite to the second light-emitting element.