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Unformatted text preview: sh whether the reflection originates from the
reflector or the object, i.e. it does not recognise the object. One solution to this
problem is to use polarisation filters. 1 Operating principle 2 3 4 5
No object in lightbeam Lenses (1) Front cover (3) Polarisor (2) Analyzer (5) Reflector (4) Fig. 15.2.3: Polarised retro-reflective sensors (source: Sick) © Festo Didactic GmbH & Co. KG • FP 1110 243 15. Special designs and variants of proximity sensors 1 2 3 4 5
The reflecting object does not produce the same polarised light beam as the reflector and is detected. Lenses (1) Front cover (3) Polarisor (2) Reflecting objector (4) Analyzer (5) Fig. 15.2.4: Polarised retro-reflective sensors (Source: Sick) The two polarisation filters for emitter and receiver are built-in between the lens of
the proximity sensor and an additional glass cover on the front of the proximity
sensor. A feature of the polarisation filter is that it only lets through light waves
which oscillate at a certain level. The light generated by the optical se...
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- Spring '12