Smoke detector chamber boundary surfaces
AssigneeAnalog Devices, Inc.
InventorShrenik Deliwala
Life of this patent
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Abstract
Device for optically detecting smoke and implementing thereof. Apparatus and methods for detecting the presence of smoke in a small, long-lasting smoke detector are disclosed. Specifically, the present disclosure shows how to build a very compact housing around the smoke detector while keeping the reflections from the housing structure to a very low value while satisfying all the other peripheral needs of fast response to smoke and preventing ambient light. This allows very small measurements of light scattering of the smoke particles to be reliable in a device resistant to the negative effects of dust. In particular, geometrical optical elements, e.g., cap and optical defection elements, are disclosed.
Claims19
An apparatus for detecting smoke within a compact footprint detector which propagates light substantially away from a smoke detector chamber, the apparatus comprising:
- a cap having an upper surface and a lower surface extending from the upper surface, the lower surface configured to define a part of the smoke detector chamber and having an apex;
- a printed circuit board (PCB), the PCB having one or more light emitting devices facing the lower surface of the cap;
- and
- a circular sidewall having an inner surface,
- wherein an upper surface of the PCB, the inner surface of the circular sidewall and a lower surface of the cap define a chamber configured to allow light traveling within the chamber to travel unimpeded in a direction parallel to the circular sidewall from the upper surface of the PCB to the lower surface of the cap, and
- wherein the lower surface is at least shaped like a paraboloid with an arcuate wall emanating from a common point that forms the apex within the smoke detector chamber, wherein the apex is formed to be a closest point of the arcuate wall to a plane of the PCB.
Dependencies are inferred from the claim text.