Smoke detectors with light shields and alarm systems including such
Smoke detectors and smoke alarms are provided which have one or more light shields configured to block or minimize the transmission of ambient light to their light receivers. Light shield configurations for facilitating such functionality are provided as well. The shield/s include a material which attenuates a majority amount of light within a particular range of light that a light source of the smoke detector may be configured to only emit and/or the range of light the light receiver may configured to only convert to photocurrent. In some cases, the shield/s surrounds the light source and/or the light receiver arranged external to an interior chamber of the smoke detector. In some cases, the shield/s may at least partially span a connection side of an external housing of the smoke detector. Alternatively, the shield may be arranged in a space between the interior chamber and the connection side of the housing.
1. A light shield to mitigate false detection of smoke by a smoke detector, wherein the light shield comprises a base plate comprising three openings and no additional openings, wherein the light shield comprises a material configured to attenuate at least a portion of the infrared light spectrum, and wherein the three openings are arranged such that:
a first opening and a second opening of the three openings are approximately 180 degrees apart from each other relative to a periphery of the base plate; and
a third opening of the three openings is approximately 90 degrees apart from the first opening and the second opening relative to the periphery of the base plate.
2. The light shield of claim 1 , further comprising a raised band extending from the base plate.
3. The light shield of claim 1 , wherein the material is configured to attenuate a majority amount of infrared light.
4. The light shield of claim 1 , wherein the material is configured to attenuate a majority amount of infrared light at a wavelength of 880 nm.
5. The light shield of claim 1 , wherein a ratio of a height of the light shield to a width of the light shield is less than approximately 1:5.