摘要 |
A fire alarm for an installation via a housing that is flush with the ceiling, having at least one light source arranged in the housing and at least one light receiver arranged in the housing, as well as a shutter disk, which seals the housing. To prevent the spreading of stray light between the light source and the light receiver via the shutter disk, a shield, for example, is provided in the shutter disk to suppress or absorb stray light.
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