Compact and Precise Electromechanical Positioning Device with Tubular Piezo Elements

TO-113 • PT 1.2430 • As of 10/2023
Peter Grünberg Institute
Quantum Nanoscience (PGI-3)

Technology

Our invention provides a device for electromechanical positioning that is compact and easy to handle. It enables precise electromechanical positioning of a rotor inside a tubular piezoelectric element with electrodes and connections for control. The device also has an elastic component connected to the piezoelectric element to exert a specific force on the rotor inside the piezoelectric element. The elastic component, which is made of a conductive material such as copper-beryllium, has a friction surface that is the contact surface between the elastic component and the rotor. In addition to the elastic component, static friction elements directly or indirectly connected to the piezo element can also be used to guide the rotor to absorb normal forces and provide constant and stable positioning. Thus, in addition to the device itself, a method for controlling the device is also disclosed.

Problem addressed

Previous electromechanical positioning devices for scanning probe microscopy have several limitations that increase complexity and cost. The use of tubular piezoelectric elements to move a wire that acts as a probe can cause unwanted vibrations during rapid movements. The need to empirically adjust the force applied to the probe by bending the wire as a rotor is time-consuming and difficult. In addition, replacing the probe usually requires replacing the entire wire and the force must then be readjusted. Limited handling space and an inclined mass unit lead to inaccurate guidance and variations in friction characteristics. The inertial drive used in previous device designs also causes vibrations and transfers forces to the base plate. Another approach requires applying high voltage to hold the inner cylinder, which can cause electrical interference in important applications such as scanning tunnelling microscopy (STM).

Solution

Our technology allows for precise and stable positioning of the rotor inside the tubular piezoelectric element, ensuring accurate measurements. The use of copper-beryllium as the elastic means provides high elasticity, hardness, and good workability. Additionally, our device is compact and easy to handle, making it suitable for various applications. The elimination of vibration in the control method enhances the overall performance and reliability. The device can also accommodate non-cylindrical rotors, allowing for versatile positioning requirements. Overall, our technology offers improved precision, stability, and ease of use compared to traditional inertia-based drives.

Benefits and Potential Use

The electromechanical positioning device finds application in a variety of fields, including scanning probe microscopy (SPM) systems. It serves as the core component of an atomic force microscope and enables precise positioning of the probe tip for nanoscale imaging and manipulation. The nano positioner can thus achieve sub-nanometre positioning steps, making it suitable for high-resolution measurements. Its ability to move continuously in the xy-direction, with segmentation of the piezoelectric elements, enables scanning over small areas. Its compact size and simplified design make it attractive for integration into existing microscopy setups. In addition, its stability to vibration and ability to exert larger forces make it suitable for other precision positioning applications in fields such as nanotechnology, biotechnology and semiconductor manufacturing.

Development Status and Next Steps

Forschungszentrum Jülich has extensive expertise in this field and holds several patents. The technology described above has already been initially verified through prototypes and is continuously being developed further. The Peter Grünberg Institute (PGI-3) – Quantum Nanoscience – already cooperates with numerous national and international companies and scientific partners. Forschungszentrum Jülich focuses on energy and cost-efficient devices, suitable for various emerging technologies. We are continuously seeking for cooperation partners and/or licensees in this and adjacent areas of research and applications.

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