Device for the detection of substrates stacked with a specific spacing

For a device for the detection of substrates stacked at an opening of a wall element, there existed the problem of constructing the detection device in such a way that the detection of the position of the substrates can be performed more flexibly with respect to the course of measurement and the measuring method employed and a defined approach of a sensor system to the semiconductor substrate to be detected is ensured in a definite position of measurement with a lowered risk of particle generation. A transmitting and receiving device ( 11 ) consists of a vertical drive mechanism ( 10 ) mounted on the wall element ( 1 ) and a sensor head ( 13 ) that can be adjusted between a lower and an upper position by means of the vertical drive mechanism ( 10 ), said sensor head being arranged so as to pivot on the vertical drive mechanism ( 10 ) in order to pivot into the opening ( 4 ). The device finds application, in particular, in the semiconductor industry for recording the state of occupancy of cassettes or containers with substrates, such as semiconductor wafers, flat-screen displays, or masks.