Operator-protecting light barrier for machine e.g. press - has electro-optical light switches, single light source and integral ceramic modulator block

摘要

An optical grid with electro-optical light switches has a single light source whose beam is deflected successively to several optical channels each contg. a light conductor. An optical receiver coupled to these channels has an associated electronic evaluation circuit. The grid is simplified in construction. The beam is deflected by an optical distribution device with an electro-optical modulator of PLZT ceramic. The modulator has an identical number of transparent control electrodes with the number of optical channels. An object lens at the output of each optical channel focusses the beam into the corresp. light conductor. The control electrodes are connected to an electronic control and analysis device. The modulator ceramic block (13) has several adjacent positive electrodes (14a to 14d) on one transmission surface and a negative electrode (15) to the other.