Piezo Flexure NanoPositioners and Scanners



Trajectory-Controlled NanoPositioners vs. Traditional MicroPositioners
PI Flexure NanoPositioners are superior to traditional positioners (with ball bearings,crossed roller bearings, etc.) in terms of resolution, accuracy, straightness and flatness.Due to the inherent friction, traditional positioners are limited to applications requiring repeatability on the order of 0.5 to 0.1 µm, while PI Flexure NanoPositioners can easily achieve resolution and repeatability in the nanometer realm and below.
 
Piezoelectric nanopositioning systems
   
Trajectory-Controlled NanoPositioners vs. "Plain" Piezo Actuators
Piezoelectric actuators offer unlimited resolution.For applications where extremely straight motion in one or more axes is needed and only nanometer deviation from the ideal trajectory can be tolerated, basic (unguided) piezo actuators are not ideal because they may not yield sufficient motion in a small enough package. PI Piezo Flexure NanoPositioners with passive or active trajectory control and integrated motion amplifiers provide an excellent solution to the problem
   
Principle of a typical PI single-plane, parallel-kinematics, flexure-guided, multi-axis nanopositioning system. Improved accuracy responsiveness and straightness compared to multi-plane (stacked) multi-axis systems (see page 4-1 in the “Tutorial” section for more details).
 
A complex muilti-dimensional Roberts-linkage flexure system
Why Flexures?
A flexure is a frictionless, stictionless linkage based on the elastic deformation (flexing) of a solid material. Sliding and rolling are entirely eliminated. In addition to absence of internal friction, flexure devices exhibit high stiffness and load capacity. Flexures are also less sensitive to shock and vibration than other guiding systems. Multi-link flexure guiding systems employed in most PI NanoPositioners provide flatness and straightness in the nanometer and microradian range, respectively. The excellent bidirectional trajectory repeatability of PI‘s designs allows higher throughput in demanding applications.

Wire-EDM cutting process provides highest- accuracy flexure guiding systems
Why Can PI Provide Superior Piezo NanoPositioner Solutions?
  • 30 years experience in designing Piezo Actuators and NanoPositioners
  • More than 100 different standard and custom models designed
  • In-house piezo ceramics manufacture ensures highest quality actuator/sensor ceramics
  • Largest variety of controllers (digital, analog, high-speed, high-power, OEM...)
  • State-of-the-art metrology lab: thermal, acoustic, seismic isolation for repeatable sub-nanometer measurements
  • In-house capacitance-position-sensor design & manufacture
  • Patented vibration-killing feedforward techniques for highest throughput

Flatness of an active trajectory-controlled nanopositioning stage over 100 x 100 µm scanning range

Application Examples:
  • Metrology
  • Photonics Alignment
  • Disk Drive Testing
  • NanoPositioning
  • Semiconductor Test Equipment
  • Lithography
  • Wafer Steppers
  • Mask Alignment
  • Precision Machining (Out-of-Roundness Turning, Boring, Grinding)
  • Scanning Interferometry
  • Surface Structure Analysis
  • Scanning Microscopy
  • Autofocus Systems
  • Biotechnology

For more information on piezo flexure NanoPositioners and piezo actuator basics see the “Tutorial: Piezoelectrics in Positioning” section.
PI NanoPositioning Solutions
  • Standard, OEM and custom designs
  • Complete solutions for NanoAutomation® tasks
  • Closed-loop operation for highest accuracy, linearity and repeatability
  • Integrated capacitive position sensors for sub-nano-meter resolution
  • Wire-EDM-cut (electric discharge machining) flexures for zero stiction/friction
  • Sub-nanometer resolution and stability
  • Optimized mechanical design, control algorithms and software for highest throughput
  • Standard, custom and OEM control electronics (digital and analog controllers, rackmount and modular systems, compatibility with advanced feedforward techniques), software
  • Ultra-responsive mechanics and control electronics for enhanced throughput
  • Finite Element Analysis (FEA) computer-designed flexures for nanometer and microradian trajectory control
  • Optional active trajectory control for sub-nanometer, sub-microradian straightness and flatness
  • Invar, titanium, steel and aluminum versions for optimized thermal match
  • Single- and multi-axis systems with large apertures for positioning and scanning

Response of a PI NanoPositioning stage to a square wave control signal shows true sub-nm positional stability, incremental motion and bidirectional repeatability