Patent ID: 8085157

Claim:
A smoke detector comprising: a hollow housing, the housing having at least one ambient inflow port and at least one ambient atmosphere outflow port; a single source of multi-frequency radiant energy carried in the housing, the source emits a beam of multi-frequency white-light energy along a first axis across and within the housing; a multi-frequency responsive sensor matrix positioned in the housing on the first axis, the matrix emitting a plurality of frequency responsive electrical signals in response to sensed incident radiant energy from the source and in response to front scattered and to reflected back scattered radiant energy; at least one of an optical filter, or, barrier positioned on the axis between the source and the matrix, the beam hits the optical filter or barrier and in the absence of particulate the multi-frequency responsive sensor matrix detects a dark picture with a white dot in the center and in the presence of particulate a progressively larger white dot; and a reflector carried in the housing between the single source and the optical filter or barrier to reflect back scattered radiant energy to the sensor matrix, wherein particulate matter in the housing scatters a portion of the beam of energy from the single source to create the back scattered energy, the sensor matrix thereby detects the spectral response of several physical light-particle interaction phenomenon including front scattering over a predetermined range of angles, backscattering and absorption or extinction reducing a light intensity of the central spot.