Vibration-absorbing Portion for Charged-particle Beam Sample Holder
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Solution Overview
Problem
Mechanical vibrations in charged-particle beam systems, such as electron microscopes, deteriorate spatial resolution due to varying natural frequencies of instrument components, requiring complex and costly vibration suppression methods, including damping alloys that are ineffective at low-strain levels.
Innovation Solution
An object-positioning device with a cylindrical sample holder and a vibration-absorbing portion using viscoelastic materials and inertial members to absorb vibrations, simplifying the structure and improving frequency range operation, thereby suppressing vibrations in multiple axes without the need for separate vibration suppressors for each component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate vibration suppressors are mounted on different components (sample holder, holder-mounting member, rotary member), then vibration suppression effectiveness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple vibration suppression functions into a single integrated vibration suppressor assembly that can be mounted on one component. This assembly includes multiple vibration-absorbing members (first and second vibration-absorbing members) that work together to suppress vibrations in different directions, eliminating the need for multiple separate suppressors on different components while maintaining comprehensive vibration suppression effectiveness.
2Reliability
If damping alloys are used to suppress vibrations, then vibration suppression is achieved, but manufacturing cost increases and effectiveness is reduced at small amplitudes
Solution Approach 1:
The patent replaces expensive damping alloys with a more economical vibration suppressor assembly using standard materials like springs and dashpots. This assembly achieves effective vibration suppression without the high manufacturing cost of damping alloys, while also maintaining effectiveness at small vibration amplitudes where damping alloys fail.
3Reliability
If damping alloys are used for vibration suppression, then some vibration damping is achieved, but effectiveness deteriorates at small strain regions required for high spatial resolution
Solution Approach 1:
The patent changes the vibration suppression mechanism from material-based damping (damping alloys) to mechanism-based damping (springs and dashpots). This parameter change allows effective vibration suppression across a wider range of amplitudes, including the small strain regions required for high spatial resolution in electron microscopes, where damping alloys are ineffective.
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
Enhances spatial resolution by directly suppressing vibrations at the sample holder, reducing manufacturing costs and effectively handling vibrations across a wide frequency range, including those smaller than atomic sizes.
Implementation Method 1
A vibration-absorbing member in the form of a hollow disk is mounted at the joint between the control knob and the sample holder to suppress vibrations in the direction of insertion of the sample holder. The vibration-absorbing member is biased toward the control knob by a compression spring via an inertial member. When the sample holder vibrates in the direction of insertion, relative vibrations occur between the sample holder and the inertial member that is inertially at rest. At this time, the vibration-absorbing member deforms (i.e., elongates and shrinks) and converts the vibrational energy into thermal energy.
Implementation Method 2
When the sample holder vibrates in the direction of insertion, relative vibrations occur between the sample holder and the inertial member that is inertially at rest.
Data Source
AI summary
An object-positioning device comprises a rod-like object holder inserted in the chamber of a charged-particle beam system for moving the object outside the chamber, a support for slideably supporting at least a part of the side surface of the object holder, thus making the rear end of the holder outside the chamber a free end, and a vibration-absorbing portion mounted on the rear end of the object holder. The vibration-absorbing portion has an operating range in which vibrational frequencies in a translational direction perpendicular to the longitudinal direction of the object holder are absorbed. The natural vibrational frequency of the object holder in the bending mode is included within the operating range of the vibration-absorbing portion.