Scanning Probe Approach via Electrostatic Feedback
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Solution Overview
Problem
Conventional scanning microscopy methods for approaching a sample surface are slow and prone to overshooting, which can damage the probe and the surface, due to the lack of precise control during the initial contact phase.
Innovation Solution
Applying an electric field between the sample surface and the probe tip, using electrodes or surface charge carriers, to create an electrostatic force that provides accurate feedback for controlling the probe's proximity, allowing for fast and precise approach without crashing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional actuator systems with stepper motors are used to move the probe towards the sample surface, then the probe can be positioned with sub-micron resolution, but the approach method becomes slow and prone to overshooting
Solution Approach 1:
The patent replaces the conventional mechanical stepper motor actuation with a piezoelectric actuator that uses piezoelectric expansion/contraction to move the probe. This substitution enables continuous, precise control of the probe position with faster response times, eliminating the step-by-step mechanical movement that causes slowness and overshooting while maintaining sub-micron positioning precision.
Solution Approach 2:
The patent implements a feedback control system that continuously monitors the probe-sample distance and adjusts the piezoelectric actuator's output in real-time. This closed-loop feedback enables dynamic adjustment of the approach speed and position, preventing overshooting while maintaining fast approach rates, thereby resolving the contradiction between speed and precision.
2Reliability
If repeated incremental movements are used to approach the sample surface, then the probe can avoid crashing, but the processing time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-positioning the probe at a safe distance from the sample surface using the piezoelectric actuator's controlled expansion, then rapidly moving it closer while continuously monitoring distance. This preliminary positioning followed by controlled rapid approach reduces the need for repeated incremental movements while maintaining probe safety through real-time distance monitoring and feedback control.
Solution Approach 2:
The patent employs dynamic control of the piezoelectric actuator to adjust the approach speed continuously based on real-time feedback. The system transitions from slow initial approach to faster movement as the probe nears the sample, then slows down again for precise positioning. This dynamic speed adjustment maintains probe safety while minimizing processing time compared to static repeated incremental movements.
3Productivity
If the probe approaches the sample surface quickly, then productivity increases, but the risk of overshooting and damage increases
Solution Approach 1:
The patent uses real-time feedback from distance sensors to continuously monitor the probe-sample separation and adjust the piezoelectric actuator's movement in real-time. This feedback control enables the system to move the probe quickly towards the sample while automatically slowing down or stopping if the distance becomes too small, thereby maintaining high productivity while preventing probe damage through automated safety control.
Solution Approach 2:
The patent implements beforehand cushioning by maintaining a controlled safety margin between the probe and sample surface through feedback control. The system is designed to maintain a minimum safe distance buffer that prevents catastrophic contact even during rapid approach, cushioning against potential damage while still enabling fast throughput through controlled rapid positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid and accurate control of the probe's approach, reducing the risk of damage and significantly decreasing the processing time for scanning probe microscopy, making it suitable for high-throughput industrial applications.
Implementation Method 1
Applying an electric field between the sample surface and the probe tip, using electrodes or surface charge carriers, to create an electrostatic force that provides accurate feedback for controlling the probe's proximity
Data Source
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AI summary
The invention is directed at a method of advancing a probe tip of a probe of a scanning microscopy device towards a sample surface. The scanning microscopy device comprises the probe for scanning the sample surface for mapping nanostructures on the sample surface. The probe tip of the probe is mounted on a cantilever arranged for bringing the probe tip in contact with the sample surface. The method comprises controlling, by a controller, an actuator system of the device for moving the probe to the sample surface, and receiving, by the controller, a sensor signal indicative of at least one operational parameter of the probe for providing feedback to perform said controlling. The method further comprises maintaining, during said controlling, an electric field between the sample surface and the probe tip, and evaluating the sensor signal indicative of the at least one operational parameter for determining an influence on said probe by said electric field, for determining proximity of the sample surface relative to the probe tip. The invention is further directed at a scanning microscopy device comprising a probe for scanning a sample surface for mapping nanostructures thereon.