An optical smoke detector and alarm device incorporating such a detector

Abstract

An optical particle sensor device (1) has a housing (2, 3) with vents (5, 6) for flow of ambient air into the device A circuit PCB (15, 70) has electronic components. A particle sensor has a chamber (50) with vents (54, 56) for inflow of air and optical components (20, 25) to detect scattering of light within the chamber. The optical components (20, 25) are mounted to the substrate and within chamber wings (59, 60), and the chamber is mounted to the substrate (15, 70), in which relative positions of the optical components and of the chamber are provided by structure of the substrate (15, 70). This structure is provided by a PCB opening (10, 71) into which the chamber (50) is fitted, and the optical components (20, 25) are mounted at or near edges of the opening with optical axes across the opening. There are directional engaging features (2) on the components (20, 25) and (30) on the circuit substrate for accurate engagement and prevention of skewing during solder reflow.

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