Scanning Probe Microscope Liquid Damping Reduces Q-Factor

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Solution Overview

Problem

Existing scanning probe microscopes face limitations in achieving high scan speeds while maintaining image quality due to mechanical stress and unpredictable variations in mechanical properties caused by coatings used to reduce the quality factor of the cantilever.

Innovation Solution

The scanning probe is accommodated in a casing filled with liquid to dampen its motion, reducing the quality factor to less than or equal to 5, thereby avoiding the need for additional coatings and minimizing mechanical stress, while maintaining the sample in an environment free from liquid to prevent contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a coating is applied to the cantilever to reduce the quality factor, then the scan speed is improved, but the mechanical stress and distortion of the beam increase

Engineering Contradiction:
Improvescan speedVSAvoidmechanical stress
Core Design Contradiction:
SpeedVSStress or pressure

Solution Approach 1:

The patent introduces an intermediary substance (liquid or gas) that acts as a damping medium between the cantilever and the surrounding environment. This intermediary reduces the quality factor through viscous damping without requiring direct contact or coating on the cantilever surface, thereby avoiding mechanical stress and distortion while still enabling faster scan speeds

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes pneumatic or hydraulic damping by enclosing the cantilever in a chamber filled with liquid or gas. The viscous properties of the fluid provide damping forces that reduce the quality factor and enable faster scanning, replacing the need for mechanical coatings with a fluid-based damping mechanism

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Speed

If a coating is applied to the cantilever to reduce the quality factor, then the scan speed is improved, but the manufacturing precision and uniformity deteriorate

Engineering Contradiction:
Improvescan speedVSAvoidbeam uniformity
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

By using an intermediary fluid medium for damping, the patent eliminates the need for surface coatings that introduce non-uniformities and defects. The fluid damping approach maintains the original uniform geometry and mechanical properties of the cantilever while achieving the desired quality factor reduction for faster scanning

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If the quality factor is reduced using external force feedback, then the scan speed is improved, but the device complexity increases

Engineering Contradiction:
Improvescan speedVSAvoidfeedback system complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent employs passive pneumatic or hydraulic damping through a fluid-filled chamber, which naturally reduces the quality factor without requiring active feedback control systems. This passive approach simplifies the device architecture by eliminating complex electronics and control algorithms while still achieving faster scan speeds through fluid viscous damping

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

This approach enables faster scanning without compromising image quality, as the liquid damping provides consistent and effective reduction of the quality factor, allowing for increased scan speeds without introducing mechanical stress or contamination risks.

Implementation Method 1

a casing (90) with a liquid (L) to dampen motion of the scanning probe

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 2

The liquid in which the probe is arranged provides for a substantial damping of the scanning probe

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP3204779B1Scanning probe microscope with a reduced q-factor
Publication Date: 2018.09.26 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP3204779B1 patent drawingFigure 1~1A
  • EP3204779B1 patent drawingFigure 1B~2B
  • EP3204779B1 patent drawingFigure 3~4

AI summary

A scanning probe microscope is provided comprising a scanning probe (10), a holder (5) for holding a sample (SMP) in an environment free from liquid. A scanning arrangement (20) is provided therein for inducing a relative motion of the scanning probe (10) with respect to said sample (SMP) along a surface of the sample (SMP). A driver (30) generates a drive signal (Sd) to induce an oscillating motion of the scanning probe (10) relative to the surface of the sample to be scanned. A measuring unit (40) measure a deflection of the scanning probe (10), and provides a deflection signal (Sδ) indicative for said deflection. An amplitude detector (50) detects an amplitude of the oscillating motion as indicated by the deflection signal (Sδ) and provides an amplitude signal (Sa) indicative for the amplitude. The scanning probe (10) is at least partly arranged in a liquid (L) to dampen motion of said scanning probe, and therewith has a quality factor Q which is less than or equal than 5. The scanning probe (10) is accommodated in a casing (90) comprising said liquid (L), the scanning probe (10) comprising a flexible carrier (11), the flexible carrier having a movable part provided with a tip (12), which tip (12) extends through an opening (91) in said casing.