Security system comprising a self-mixing laser sensor and method of driving such a security system

摘要

A security system is described, comprising a sensor module (15) which accommodates a laser sensor (10) working with self-mixing interference. The laser sensor (10) generates measurement data which are related to the velocity of an object such as the body of a human being and, optionally, the distance between the laser sensor (10) and the object. Dependent on the measurement data assembled by the laser sensor (10) and supplied to a control circuit (30) such as an airbag computer, the airbag computer activate security means such as an airbag (35)in order to prevent injuries of the human body. Furthermore, a method of driving such a security system is described.

主权项

1. A security system comprising:
a sensor module (15) comprising at least one laser sensor (10) working with self-mixing interference, the laser sensor having a Rayleigh range; at least one optical element for focusing light; a control circuit (30) and security means; wherein the sensor module (15) comprises means to generate first measurement data which are directly or indirectly related to at least one first velocity component of an object (400, 351, 700) relative to the sensor module (15), and wherein the control circuit (30) comprises means to receive the first measurement data generated by the sensor module (15) and to activate the security means in dependence upon the first measurement data received from the sensor module as soon as the first measurement data exceeds a defined first threshold value; wherein the laser sensor (10) in combination with the at least one optical element has a focal region (12) between the optical element and the object, and the distance between the focal region (12) and the object is greater than one Rayleigh range.