Patent ID: 7478699

Claim:
A vehicle passenger detecting device comprising: a judging circuit, which judges whether a passenger seated on a seat is a child or not, based on a load acting on each of areas of a front inner area, a front outer area, a rear inner area and a rear outer area of a seat portion of the seat for a vehicle, wherein a vehicle exterior side of the seat is disposed with a anchor, which connects a seat belt provided with a tongue plate to a body of the vehicle, and a vehicle interior side of the seat is disposed with a buckle in which the tongue plate is releasably locked, wherein the front inner area of the seat portion is provided with a front inner area sensor which detects the load acting on the front inner area, the front outer area of the seat portion is provided with a front outer area sensor which detects the load acting on the front outer area, the rear inner area of the seat portion is provided with a rear inner area sensor which detects the load acting on the rear inner area, and the rear outer area of the seat portion is provided with a rear outer area sensor which detects the load acting on the rear outer area, wherein the judging circuit, with a fastened state of the seat belt, is configured to compare a total load value obtained by the area sensors of an entire area with critical values, which prescribe a predetermined range, and to judge whether or not the total load value is within the predetermined range, and when the total load value is within the predetermined range, the judging circuit is configured to compare a front outer load value obtained by the front outer area sensor with a first threshold, and compare a ratio of the front outer load value obtained by the front outer area sensor to a front inner load value obtained by the front inner area sensor with a second threshold, wherein if the front outer load value is the first threshold or more and the ratio of the front outer load value to the front inner load value is the second threshold or more, the judging circuit is configured to judge that a seated passenger is a child, or the judging circuit is configured to compare the ratio of both outer load values obtained by both of the outer area sensors to both inner load values obtained by both of the inner area sensors with a third threshold, wherein if the ratio of both outer load values to both inner load values is the third threshold or more, the judging circuit is configured to judge that a seated passenger is a child.