Abstract:
An optoelectronic sensor (10) for detecting objects in a monitored zone (20) is provided which has the following: a front screen (38); a light transmitter (12) for transmitting a light beam (16); a movable deflection unit (18) for the periodic sampling of the monitored zone (20) by the light beam (16); a light receiver (26) for generating a received signal from the light beam (22) remitted by the objects; at least one test light transmitter (42); at least one test light transmitter (42), at least one test light receiver (44) and at least one test light reflector (48) which span a test light path (46a-b) through the front screen (38); and an evaluation unit (32) which is configured to acquire pieces of information on the objects in the monitored zone (20) from the received signal and to recognize an impaired light permeability of the front screen (38) from a test light signal which the test light receiver (44) generates from test light which is transmitted from the test light transmitter (42) and which is reflected at the test light reflector (48). In this respect, the test light reflector (48) is arranged such that it moves along with the deflection unit (18).
Abstract:
A laser scanner, in particular a safety laser scanner, in accordance with the operating principle of the time of flight process, comprising a light transmission unit having at least one light transmitter for transmitting a polarized transmitted light beam into a monitored zone; a light reception unit having at least one light receiver for detecting the polarization component of the light reflected in the monitored zone being orthogonal to the polarization direction of the transmitted light beam, and/or the polarization component of the light reflected in the monitored zone being parallel to the polarization direction of the transmitted light beam, and for generating a received signal corresponding to the detected orthogonal polarization component and/or the detected parallel polarization component; and an evaluation unit configured to evaluate the time development of the detected orthogonal polarization component and/or of the detected parallel polarization component.
Abstract:
An optoelectronic sensor (10) has a circumferential front screen (42) comprising a curvature both in a circumferential direction and in a transverse height, thus focusing light reflected at the inside of the front screen (42). Test light passes from a test light transmitter (50a-f) through the front screen (42) to a reflector (52a-f) and subsequently onto a test light receiver (56a-b). A decreasing light transmissivity of the front screen (42) is detected based on a decrease of a signal generated by the test light in the test light receiver (56a-b). The test light receiver (56a-b) is arranged on a same side of the front screen (42) as the reflector (52a-f) such that the test light path (54a-f) leads from the reflector (52a-f) via reflection on the inside of the front screen (42) to the test light receiver (56a-b).