Settling time

The time for stage to move to a commanded position and settle to within 2% of its final value of the step size. A small signal step response reflects the dynamic characteristics of the system in more detail. Therefore, small signal settling time is normally used in the specifications of nPoint’s nanopositioning products — the […]

Resonant frequency

The first (or the lowest) resonant frequency of a nanopositioner. The resonant frequency could be of the mode along the motion axis or in other axes including rotation and other complex modes. In general, the higher the resonant frequency of a system, the higher the stability and the wider working bandwidth the system will have. […]

Position noise

The amplitude of the stage shaking when it is on a static command. It is usually measured and specified with RMS (1 σ) value. It is commonly used to define the resolution of the nanopositioners and is a combination of sensor noise, driver electronics noise and command noise, etc.

Linearity error

The error between the actual position and the first-order best fit line (straight line). nPoint’s nanopositioning products are calibrated with laser interferometry and the non linearity errors are compensated with a fourth order polynomial.

Hysteresis

The positioning error between forward scan and backward scan. A closed-loop control is an ideal solution for the problem. Capacitance sensors are normally used in nPoint’s nanopositioners to provide feedback signals. It is a non-contact displacement measurement technique, which is hysteresis free.