Abstract: A distance-determining system, in particular a distance-monitoring system, preferably a unidirectional distance-monitoring system, with at least one first monitoring unit and with at least one second monitoring unit, wherein at least the first monitoring unit includes a transmitter unit that is configured to emit a sound signal, in particular an ultrasound signal, and an electromagnetic signal, in particular an electromagnetic high-frequency signal, wherein at least the second monitoring unit includes a receiver unit that is configured to receive the sound signal and the electromagnetic signal such that a distance between the first monitoring unit and the second monitoring unit can be determined on the basis of the runtime difference between the sound signal received by the receiver unit and the electromagnetic signal received by the receiver unit and allocated to the received sound signal.

Abstract: An apparatus and method for surface profile measurements of large samples. The sample is held by a stationary chuck, while a four-axis (X, Y, Z and theta axis) positioning assembly manipulates and positions an overhead scan assembly and measurement stylus to perform the profilometry. To observe the sample surface in the vicinity of the measurement stylus, an illumination and imaging capability is also provided. Backlash and error are reduced in the Z axis assembly through use of cams and cam followers, and in the scan assembly through use of multiple tensioned wires, with low-friction sliding elements. The apparatus reduces vibration and supports heavy (up to 400 kg) samples while allowing accurate profile measurements.