Optical Occupant Position Sensor for Airbag System

An occupant position sensor is the key device for the smart airbag system to increase the reliability of conventional airbag systems. In the smart airbag system, the degree of airbag explosion is controlled by the data from the occupant position sensor. High accurate occupant position sensing is needed, which might be difficult by supersonic technologies.This paper reports a novel optical occupant position sensing device suitable for the smart airbag system, which measures the distances from the sensor to 2 dimensional multiple points on the occupant. The method to measure the distances is optical triangulation using photo-diode array pairs and a data processing IC.In this paper. the occupant position recognition is demonstrated using the data obtained by 2 dimensional distance measurement of the occupant position sensing device, in the accuracy of 3cm at the distances of 75cm within the optical view angle of 35 and 53 degrees in horizontal and vertical respectively. Total distance measurement points of this device are 4×44. This paper also describes the recognition possibility of 4 basic occupant position using these distance data, which is needed for airbag explosion control in smart airbag system.