Specimen Holder Thermal Drift Compensation
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Solution Overview
Problem
Conventional specimen holders experience significant thermal drift due to temperature changes, leading to specimen misalignment and prolonged waiting times for thermal equilibrium, which hinders high-resolution imaging and analysis, especially in electron microscopes.
Innovation Solution
A specimen holder design featuring a thermal drift adjusting unit with a different thermal expansion coefficient than the main shaft unit, combined with a control mechanism such as a hard ball for centering, and a pushing mechanism to mitigate thermal expansion effects, allowing for efficient cooling and heating while minimizing thermal drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the specimen holder shaft unit is cooled to low temperature for high-resolution imaging, then the thermal drift is reduced, but the waiting time for thermal equilibrium increases
Solution Approach 1:
The patent applies thermal expansion compensation by using a thermal drift adjusting unit made of a material with a different thermal expansion coefficient than the specimen holder shaft unit. When the shaft unit is cooled, the thermal drift adjusting unit contracts at a different rate, and the control mechanism moves it to compensate for the thermal drift, enabling faster thermal equilibrium while maintaining imaging resolution.
2Stability of the object's composition
If the thermal drift adjusting unit is moved to compensate for thermal expansion, then the specimen position stability is improved, but the device complexity increases
Solution Approach 1:
The patent segments the specimen holder into functionally independent units: the specimen holder shaft unit, the thermal drift adjusting unit, and the control mechanism. This segmentation allows each component to perform its specific function independently, achieving specimen position stability through coordinated movement of the thermal drift adjusting unit while keeping the overall structure manageable.
Solution Approach 2:
The thermal drift adjusting unit acts as an intermediary element between the specimen holder shaft unit and the external environment. It absorbs and compensates for thermal expansion effects, serving as a mediator that protects the specimen position from thermal drift without requiring complex active control systems.
3Loss of energy
If the outer tubular unit is designed to house the specimen holder shaft unit with thermal insulation, then the heat inflow is reduced, but the device complexity increases
Solution Approach 1:
The patent employs a nested structure where the specimen holder shaft unit is housed within the outer tubular unit. This nested design provides thermal insulation by creating concentric layers between the cold specimen holder and the warmer external environment, reducing heat inflow while maintaining a compact and relatively simple overall structure.
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 design significantly reduces thermal drift, stabilizes temperature, and enables immediate high-resolution imaging and analysis, reducing waiting times and improving productivity by maintaining consistent vacuum conditions and reducing heat inflow.
Implementation Method 1
a thermal drift adjusting unit (4) made of a material having a different thermal expansion coefficient from a thermal expansion coefficient of the specimen holder shaft unit (3) and partially in contact with the specimen holder shaft unit (3)
Implementation Method 2
a cooling mechanism (7) capable of cooling the specimen holder shaft unit (3)
Data Source
AI summary
In at least one embodiment, a specimen holder includes a specimen holder shaft unit having a specimen and/or specimen mesh setting unit, an outer tubular unit capable of housing the specimen holder shaft unit, a thermal drift adjusting unit made of a material having a different thermal expansion coefficient from a thermal expansion coefficient of the specimen holder shaft unit and partially in contact with the specimen holder shaft unit, and a control mechanism which controls movement of the thermal drift adjusting unit toward a center direction of a specimen.