Abstract: Anticollision-lamp operable in day-light and at night. It is known to provide separate day-light lamps with a high light output, and night-lamps with little infrared radiation in order not to dazzle night vision goggles. The anticollision light according to the invention comprizes at least one optical interference filter (11) with an average transmission factor in the infrared which is less than 4% of its value in the visible white or red. Preferred embodiments comprize among others: an average transmission factor in a spectral domain larger than 80%, preferably 90% and most desirably 95%; the combination of an interference filter (11) with an absorption filter (10) transparent for red light; an interference filter (11) consisting of several plane elements arranged octagonally; and a band-pass interference filter with a transmission domain situated in the visible red and the transmission factor of which is at least 104 times larger than in an infrared domain.

Abstract: A sensor head includes a sensor element whose measurement signal can be fed to a comparator. The comparator compares the measurement signal to a threshold value and forwards a binary output signal to a transmission circuit. The sensor head is provided with electric energy via a proprietary two-wire line. In addition, the output signal can be transmitted from the transmission circuit via the two-wire line to a higher-order control module that is located outside of the sensor head. At least two sensor heads of this type can be connected to the control module.