Nanoindenter Ultrasonic Probe Tip for Multi-Property Characterization
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Solution Overview
Problem
Existing micro tools, such as Atomic Force Microscopes and nano indenters, are limited in their ability to simultaneously determine mechanical properties like elasticity modulus, surface hardness, and other material characteristics of samples at the nanoscale due to their variable tip geometry and limited dynamic response, which restricts their bandwidth and capability for comprehensive material characterization.
Innovation Solution
A probe tip system that utilizes a combination of a micro tool and an ultrasonic transducer to transmit longitudinal resonant high-frequency ultrasonic waves, allowing for the determination of time-dependent properties like complex modulus, adhesion, and friction coefficient by comparing acoustic contact impedance with electromechanical impedance, using a multi-mode ultrasonic transducer interfaced with nano indentation and Scanning Probe Microscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If AFM and mechanical cantilever based systems are used for imaging at nanometer and sub-nanometer scales, then imaging resolution is improved, but the ability to simultaneously determine mechanical properties is lost due to variable tip geometry
Solution Approach 1:
The patent applies universality by designing a probe tip system that performs multiple functions: it can both image surfaces at nanometer resolution and simultaneously determine mechanical properties such as elasticity modulus, hardness, and adhesion. The standardized tip geometry with integrated ultrasonic transducer enables the same probe to conduct both imaging and mechanical characterization without requiring variable tip geometries.
Solution Approach 2:
The patent merges imaging capabilities with mechanical property determination by integrating an ultrasonic transducer directly into the probe tip structure. This combination allows the system to perform both surface imaging and mechanical characterization (elasticity modulus, hardness, adhesion) using a single integrated probe rather than separate instruments.
2Speed
If AFM devices operate in tapping mode or resonance modes, then dynamic response is improved, but the ability to render material properties such as elasticity modulus or hardness is lost
Solution Approach 1:
The patent utilizes mechanical vibration by employing ultrasonic frequency vibrations (20 kHz to 2 MHz) of the probe tip to enhance dynamic response. The vibrations enable the system to operate in resonance modes while simultaneously determining material properties through analysis of the vibrational response, combining the benefits of dynamic operation with accurate material characterization.
Solution Approach 2:
The patent applies parameter changes by operating the ultrasonic transducer across a wide frequency range (20 kHz to 2 MHz) and analyzing the dynamic response at different frequencies. This enables the system to determine material properties such as elasticity modulus and hardness by measuring how the probe tip's vibrational characteristics change when interacting with different materials.
3Device complexity
If nano indenters use electrostatic or voice coils for actuation and sensing, then device complexity is reduced, but dynamic response bandwidth is limited to 250 Hz or less
Solution Approach 1:
The patent replaces the traditional electrostatic or voice coil actuation and sensing mechanisms with an ultrasonic transducer-based system. This substitution enables the system to achieve dynamic response bandwidths exceeding 250 Hz (up to 2 MHz) while maintaining relatively simple device architecture, as the ultrasonic transducer integrates both actuation and sensing functions in a single component.
4Speed
If millimeter scale impedance shaker heads are used for operational bandwidth up to 1000 Hz, then dynamic response is improved, but the ability to perform nano scale characterization with interchangeable probe tips is lost
Solution Approach 1:
The patent applies segmentation by separating the ultrasonic transducer from the probe tip, allowing the tip to be interchangeable while the transducer remains fixed. This enables nano-scale characterization capabilities to be maintained through various tip geometries while achieving extended bandwidth (up to 1000 Hz or higher) through the ultrasonic transducer's high-frequency operation.
Solution Approach 2:
The patent transitions from millimeter-scale impedance shaker heads to nanoscale probe tips by reducing the contact dimension while maintaining or extending the frequency bandwidth. The ultrasonic transducer enables high-frequency operation (up to 2 MHz) at the nanoscale, providing both enhanced spatial resolution and extended dynamic response bandwidth simultaneously.
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 the evaluation of material characteristics across thin films, bulk materials, and eutectic alloys with improved resolution and dynamic response, capable of determining mechanical properties such as storage and loss modulus, hardness, adhesion, friction, and stress/strain within a frequency range of 100 kHz to 2 MHz, enhancing the characterization capabilities beyond the limitations of existing tools.
Implementation Method 1
The probe tip includes an ultrasonic transducer that directs ultrasonic waves towards a sample
Implementation Method 2
transducer propagates ultrasonic waves at a resonant frequency with a range of frequencies between 100 kHz to 2 MHz
Implementation Method 3
an ultrasonic transducer coupled to the base on a side opposing the elongated column
Data Source
AI summary
A multimode ultrasonic probe tip and transducer integrated into a micro tool, such as a nano indenter or a nano indenter interfaced with a Scanning Probe Microscope (SPM) is described. The tip component may be utilized to determine mechanical properties or characteristics of a sample, including for example, complex elastic modulus, hardness, friction coefficient, and strain and stress at nanometer scales and high frequencies. The tip component is configured to operate at multi-resonant frequencies providing sub-nanometer vertical resolution. The tip component may be quasi-statistically calibrated and contact mechanics constitutive equations may be utilized to derive mechanical properties of a sample. Contact mechanical impedance and acoustic impedance may also be compared.