Specimen Tip Holder Assembly for TEM Tilt Range
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Solution Overview
Problem
Conventional specimen holders for transmission electron microscopes restrict sample tilt range due to their bulky design and lack of fine-tuning capabilities, particularly in achieving the eucentric height, which limits high-resolution imaging and three-dimensional model creation through electron tomography.
Innovation Solution
A specimen tip holder assembly with integrated in situ height adjustment and reduced-size specimen tips, allowing for precise Z-axis adjustment and increased tilt angles, enabling accurate focus and view maintenance during sample tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional specimen holders are used, then sample support is provided, but tilt range is restricted due to bulky design
Solution Approach 1:
The specimen holder is divided into separate functional components: a reduced-size tip holder for mounting the specimen tip, and a separate actuator mechanism for height adjustment. This segmentation allows the main holder body to be compact while providing independent adjustment capabilities, thereby increasing tilt range without sacrificing support functionality.
Solution Approach 2:
The invention introduces a new degree of freedom by implementing height adjustment perpendicular to the tilt axis. The actuator mechanism moves the tip holder along the optic axis (Z-direction), enabling eucentric height adjustment independent of tilt operations. This dimensional addition resolves the contradiction by providing compact tilt capability while adding adjustment freedom in another dimension.
2Measurement precision
If conventional specimen holders are used, then sample mounting is enabled, but eucentric height adjustment is insufficient
Solution Approach 1:
The holder structure incorporates dynamic adjustment capabilities through the actuator mechanism that can move the tip holder to different heights. This dynamic element allows precise eucentric height positioning while maintaining a relatively simple overall structure. The adjustment is achieved through a straightforward linear actuation system rather than complex mechanical linkages.
Solution Approach 2:
The actuator mechanism is designed to be operable from outside the evacuated cavity, allowing the user to perform height adjustment independently without requiring complex internal mechanisms or assistance from other system components. The simple actuator design enables self-contained height adjustment functionality.
3Reliability
If bulky specimen holders are used, then sample support is adequate, but focus and view are lost during tilting
Solution Approach 1:
The eucentric height adjustment is performed before tilting operations to pre-position the specimen at the correct height. This preliminary action ensures that the specimen remains in focus during subsequent tilting, eliminating the need for continuous focus adjustments and maintaining view consistency throughout the tilting range.
Data Source
AI summary
A specimen tip holder assembly for mounting a specimen tip in a transmission electron microscope (TEM) is described. The specimen tip holder assembly comprises a tip holder for supporting a specimen tip. The tip holder is coupled to an elongate support for movement in a direction substantially perpendicular to the axis of the support. An actuator is mounted to the support for causing motion of the tip holder relative to the support.