Patent ID: 7038189

Claim:
An optoelectronic dust sensor comprising: one or more light-emitting units irradiating one or more dust passage routes with light; one or more light-receiving units receiving light reflected from dust passing through at least one of the dust passage route or routes; one or more main body housings at least partially enclosing the optoelectronic dust sensor; one or more passage holes, provided at at least one of the main body housing or housings, for permitting introduction of dust from the exterior to at least one of the dust passage route or routes; one or more openings, provided at at least one of the main body housing or housings, for permitting discharge of dust from at least one of the dust passage route or routes to the exterior; wherein presence, absence, and/or concentration of dust is detected based on received-light output from at least one of the light-receiving unit or units; at least one of the opening or openings is larger than at least one of the passage hole or holes; at least one detection report means for detecting and reporting at least one large amount(s) of dust accumulated at the interior of at least one of the main body housing or housings of the optoelectronic dust sensor; and wherein said detection report means keeps track of a time during which a signal level from the light-receiving unit is maintained at or above a predetermined level, and when the time exceeds a predetermined threshold said detection report means reports that a large amount of deposit(s) may have collected within the main body housing(s).