Homogenous Electrical Field Ensures High Linearity
The PI arrangement with an additional guard ring electrode generates a very homogenous field in the active area.
In addition, all electronics from PI use integrated linearization methods that correct parallelity errors between the sensor plates. Depending on the material used, capacitive sensors provide excellent long-term stability that is largely independent of thermal influences.
Measurement of Vibration, Flatness, Thickness
The high dynamics of the PISeca system also allows measurement with excellent resolution of vibrations and oscillations. The evenness of a rotating workpiece or differences in thickness in the nanometer range can thus also be detected. For example, one possible field of application is the production of disk drives or the active compensation of vibration.
Measuring Distances with Nanometer Accuracy
Capacitive sensors reliably measure shortest distances. The quantity to be measured is the change of capacitance between the surface of the sensor head and the target surface using a homogenous electric field. The achieved accuracy lies the subnanometer range. Absolute values are determined with a well-adjusted, calibrated system.
Parallel Metrology / High-Precision Multi-Axis Measurements
For closed-loop, multi-axis nanopositioning tasks, high-performance stages with capacitive sensors combine direct metrology and paralles kinematics. When used in multi-axis nanopositioning systems, this allows measuring all degrees of freedom at the same time and actively compensating guiding errors (Active Trajectory Control concept). Here, capacitive sensors are the most precise measuring systems to give the best position resolution results.
Force Sensors with Micronewton Sensitivity
Capacitive single plate sensors are often used as high-resolution force sensors for contact-free measurement in the micronewton range. Here, minimal deviations in distance are measured contact-free over longer distances are resolutions in the subnanometer range without affecting the process to be measured. The defined stiffness of the system enables calculation of the force.
Nanopositioning / Closed Loop Systems
Nanopositioning is one application of the high-resolution displacement measurement. Here, capacitive two-plate sensors measure the direct distance and actual position of the moved object with the utmost precision. The high sensor bandwidth also allows closed-loop control in dynamic applications.
Measuring Straightness and Flatness, and Active Cross Talk Compensation
One possible application for it is the cross talk measurement in nanopositioning. This allows detecting undesired cross talking of the motion to another axis and active compensation in real time. The high sensor bandwidth provides excellent dynamic performance.