Physik Instrumente (www.physikinstrumente.com) has unveiled its new piezo stepping drives, which can be combined with a linear encoder for nanometer accuracy over the complete scanning range. The new drives are available for PIFOC focusing systems for microscope objectives.

The N-725 PIFOC scanner for microscope objectives with NEXACT piezo stepping drives offers travel ranges of up to 1mm along the optical axis. The N-725’s focusing system can achieve transient times of up to 20ms for steps of 200NM. It has a compact design and is no larger compared to conventional, piezo-based PIFOC objective stages.

The focal plane can be changed with a single mechanism due to the combination of long travel ranges and high resolution. Therefore, there is no need for combining Z-positioning of the objective (with stepper motor and more piezo stages).

The NEXACT piezo stepping drive combines the best traits of piezomotor principles in a compact unit, including high speed, high resolution and high force. The feed motion can be achieved solely through the nanometer-accurate motion of clamped piezo actuators – high resolution, non-wearing and with controllable speed.

High positional resolution is achieved in a stepping mode over the complete travel range in high drive forces. Furthermore, the high stiffness allows a rapid oscillatory motion with resolutions of up to 30 pm and an amplitude of 7 micrometers.

The drive does not need to be powered and is self-locking when it has reached its target. Its position is stable in the nanometer range, thus there is no jitter about its target position compared with stepper motors and servo motors.