Electron Microscope Vacuum Switching for Power-Saving Standby
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Solution Overview
Problem
In electron microscopes, the cryogenic liquid in sample contamination preventive devices evaporates, causing a rapid rise in temperature of cooling fins, leading to the release of gas molecules and impairment of the vacuum inside the electron optical column, potentially damaging the sputter ion pump.
Innovation Solution
An electron microscope with a controller that switches the operation mode from active to power-saving by heating the adsorptive member to release adsorbed gases using a second vacuum pumping unit capable of higher pressures, then switching back to the active mode at a preset time, reducing user labor and ensuring efficient energy saving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electron microscope is deactivated to save energy, then power consumption is reduced, but the cryogenic liquid evaporates and damages the sputter ion pump
Solution Approach 1:
The controller performs preliminary heating of the adsorptive member and activates the second vacuum pumping unit before deactivating the electron lenses. This preliminary action prevents the cryogenic liquid from evaporating and damaging the sputter ion pump during the deactivated period, allowing energy savings without compromising pump reliability
Solution Approach 2:
The second vacuum pumping unit acts as an intermediary protective measure. When the electron microscope is deactivated, this pump maintains vacuum in the electron optical column, preventing damage to the sputter ion pump from evaporated cryogenic liquid while allowing the main system to be powered down
2Reliability
If the adsorptive member is heated to release adsorbed gases, then vacuum quality is maintained, but energy consumption increases
Solution Approach 1:
The heating of the adsorptive member is performed periodically only when the electron microscope transitions to or from deactivated state, rather than continuously. This periodic heating maintains vacuum quality while minimizing energy consumption by activating the heating element only when necessary
3Reliability
If the sputter ion pump is protected from damage, then system reliability is improved, but device complexity increases
Solution Approach 1:
The vacuum pumping system is segmented into two distinct units: the first sputter ion pump for maintaining high vacuum during operation, and the second vacuum pumping unit for protective operations during deactivation. This segmentation allows each pump to be optimized for its specific function and protects the critical sputter ion pump from damage without requiring complex modification of the original system
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 solution allows for easy energy saving by preventing damage to the vacuum pumping units and reducing user intervention, ensuring the electron microscope operates efficiently and effectively.
Implementation Method 1
a cooling section disposed in the electron optical column and operative to cool an adsorptive member to thereby adsorb contaminant materials that contaminate a sample
Implementation Method 2
a heating section for heating the adsorptive member
Implementation Method 3
the cryogenic liquid filled in the refrigerant tank evaporates with the elapse of time. Finally, the liquid will disappear, whereupon the temperature of the fins rises rapidly
Implementation Method 4
the interior of the electron optical column is evacuated by a sputter ion pump
Data Source
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AI summary
There is provided an electron microscope capable of easily achieving power saving. The electron microscope (100) includes a controller (60) for switching the mode of operation of the microscope from a first mode where electron lenses (12, 14, 18, 20) are activated to a second mode where the electron lenses (12, 14, 18, 20) are not activated. During this operation for making a switch from the first mode to the second mode, the controller (60) performs the steps of: closing a first vacuum gate valve (50), opening a second vacuum gate valve (52), and vacuum pumping the interior of the electron optical column (2) of the microscope by the second vacuum pumping unit (40); then controlling a heating section (26) to heat an adsorptive member (242); then opening the first vacuum gate valve (50), closing the second vacuum gate valve (52), and vacuum pumping the interior of the electron optical column (2) by the first vacuum pumping unit (30); and turning off the electron lenses (12, 14, 18, 20).