| 摘要 |
The invention relates to a device and a method for identifying an object O in an opening that can be closed by means of a mobile element ( 12 ). Light is fed into at least one fiber-optic light guide ( 33, 34 ) from a light source ( 1, 2 ), and variations in the received light are detected by means of at least one receiver (Ea, Eb), the fiber-optic light guide being arranged at least partially along the edge of the opening ( 11 ). A first fiber-optic light guide sends light transversally to the length thereof, said light being then received by a second fiber-optic light guide transversally to the length thereof. The second fiber-optic light guide ( 34 ) is connected to the receiver (Eb). The fiber-optic light guides are arranged on the edge of the opening ( 11 ) in such a way that a light field (F) at least partially bridging the opening is produced. At least one light source ( 1, 2 ) and at least one receiver (Ea, Eb) are respectively associated with each fiber-optic light guide ( 33, 34 ), and a clock circuit is used to alternately feed the light received by the respective receiver into the fiber-optic light guides. Comparison means are used to compare the signals on the receivers in order to identify the object.
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