25 printing mark sensors printing mark sensors are

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Unformatted text preview: nsor (e.g. red light LED) oscillates on several levels of polarisation. The polarisation filter of the emitter lets through only that part of light which oscillates at a specific polarisation level. In this way only the polarised light beam reaches the reflector (there is no need for the ambient light level to be taken into account, because this will be suppressed in the receiver anyway). The reflector which is in the shape of a triple mirror then rotates the polarisation level by 90°. In order that the light reflected by the triple mirror can be received by the receiver, the series-connected polarisation filter is rotated by 90° opposite to the emitter polarisation filter. If there is a reflecting object in the lightbeam then in contrast to the triple mirror, polarisation is maintained. In this way, the light from the object which hits the receiver polarisation filter is not allowed to pass through to the receiver and the receiver evaluates the absence of the light signal as "object available". 244 © Fe...
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This note was uploaded on 11/01/2012 for the course CHEMICAL 102 taught by Professor Jamesrodriguez during the Spring '12 term at Universidad Politécnica de Cartagena.

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