Motor vehicle sensor for detecting inadequate ambient light - contains illumination intensity detector sensitive to amt. of cloud by using polariser, to increase value for threshold switch with greater cover

摘要

The sensor contains a detector of illumination-intensity followed by a threshold switch which changes its switching state when there is insufficient ambient intensity. The detector output signal is evaluated according to the degree of cloud cover. For heavier cover, the illumination intensity value required to trigger the switch is increased. The degree of cloud cover is detected using the polarisation of the ambient light. The degree of polarisation is determined using a polarisation filter arranged before the detector and vertically adjusted and inclined wrt. the horizontal according to the inclination of the front of the vehicle. USE/ADVANTAGE - Automatically switches on driving lights when appropriate according to ambient light intensity.