Vacuum valve with optical sensor

A vacuum valve system comprising a

• vacuum valve for controlling a volume flow or mass flow and/or for gastight sealing off a process volume, wherein the vacuum valve has
• a valve seat, which runs for closing the valve opening in a gas-tight manner, and
• at least two sealing faces, wherein
• a first sealing face of the at least two sealing faces is provided by the valve seat and runs around the valve opening, and
• a second sealing face of the at least two sealing faces is provided by the valve closure and is formed correspondingly to the first sealing face,
• a drive unit coupled to the valve closure, which drive unit is designed in such a way that the valve closure
• can be varied and adjusted in a defined manner in order to provide respective valve opening states and
• is movable from an open position, in which the valve closure at least partially releases the valve opening, into a closed position, in which the second sealing face is pressed in the direction of the first sealing face and the valve opening is closed in a substantially gastight manner, and back,
• wherein the vacuum valve system has an optical sensor unit, wherein the optical sensor unit
• is designed to detect an optical measurement signal and
• is arranged in such a way, and an optical detection axis of the optical sensor unit is oriented in such a way that the measurement signal with respect to at least part of one of the sealing faces can be detected,
• wherein the measurement signal can be generated in a test position of the valve closure.