Bifocal Beamformer for Simultaneous TEM and STEM Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electron microscope systems require time-consuming and complex reconfiguration to switch between transition electron microscopy (TEM) and scanning transmission electron microscopy (STEM) modes, as they use different lenses, detectors, and configurations for each mode, making it difficult to perform both techniques simultaneously.
Innovation Solution
A dual beam bifocal charged particle microscope system that splits electrons into two beams with different focal planes, allowing for simultaneous TEM and STEM imaging using a single detector, with a bifocal beamformer modifying the focal properties of the beams to enable rapid switching between modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different lenses and detectors are used for TEM and STEM modes, then imaging quality is improved, but device complexity and switching time increase
Solution Approach 1:
The patent implements a universal detector and lens system that can operate in both TEM and STEM modes. The single detector is positioned to receive electrons from the objective lens, and the system uses a beam forming aperture and condenser lens configuration that supports both imaging modes without requiring separate dedicated components for each mode, thereby reducing device complexity while maintaining imaging quality
Solution Approach 2:
The patent employs dynamic beam control mechanisms including a beam forming aperture and condenser lens that can be rapidly adjusted between TEM and STEM configurations. The system dynamically reconfigures the electron beam path and focal properties through electromagnetic lens control, enabling fast mode switching without physical component changes, thus resolving the contradiction between maintaining imaging quality and reducing switching time
2Measurement precision
If detector reconfiguration is required for mode switching, then mode-specific optimization is improved, but switching time and productivity decrease
Solution Approach 1:
The patent pre-configures the detector position and lens system to be compatible with both TEM and STEM modes from the outset. The detector is positioned in the back focal plane of the objective lens, and the condenser lens is designed with adjustable aperture characteristics that can accommodate both modes. This preliminary universal configuration eliminates the need for time-consuming detector reconfiguration during mode switching, thereby improving productivity while maintaining mode-specific optimization
Solution Approach 2:
The patent achieves mode switching through rapid changes in electromagnetic lens parameters and beam aperture settings rather than physical detector reconfiguration. The condenser lens current and aperture diameter are dynamically adjusted to transform the beam between TEM and STEM configurations, enabling fast switching while preserving the optimized imaging characteristics of each mode through precise parameter control
3Measurement precision
If beam focus adjustment is performed during mode switching, then focusing precision is improved, but switching time and operational efficiency decrease
Solution Approach 1:
The patent uses dynamic electromagnetic lens control to rapidly adjust beam focus during mode switching. The condenser lens and objective lens currents are programmably adjusted to achieve the appropriate focal conditions for TEM or STEM mode. This dynamic focusing mechanism eliminates the need for manual focus adjustment and beam drift waiting periods, significantly reducing switching time while maintaining focusing precision through automated lens parameter control
Solution Approach 2:
The patent pre-calculates and stores the optimal lens current parameters for both TEM and STEM modes. When switching between modes, the system automatically applies the pre-determined lens parameters, eliminating the need for iterative focus adjustment and beam drift compensation. This preliminary parameter preparation enables rapid mode switching while ensuring focusing precision is achieved immediately upon mode change
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 simultaneous high-resolution STEM and electron diffraction imaging, allowing for precise alignment and efficient acquisition of complementary information without the need for detector reconfiguration, significantly reducing the time required to switch between imaging modes.
Implementation Method 1
an electron emitter configured to emit electrons towards the sample
Implementation Method 2
a bifocal beamformer positioned between the electron emitter and the sample holder. The bifocal beamformer is configured to form the plurality of electrons into a first electron beam and a second electron beam, and modify the focal properties of at least one of the first electron beam and the electron particle beam
Implementation Method 3
Emissions resultant from the STEM beam and the TEM beam being incident on the sample can then be detected by a single detector or detector array
Data Source
AI summary
Methods for using a single electron microscope system for investigating a sample with TEM and STEM techniques include the steps of emitting electrons toward the sample, forming the electrons into a two beams, and then modifying the focal properties of at least one of the two beams such that they have different focal planes. Once the two beams have different focal planes, the first electron beam is focused such that it acts as a STEM beam that is focused at the sample, and the second electron beam is focused so that it acts as a TEM beam that is parallel beam when incident on the sample. Emissions resultant from the STEM beam and the TEM beam being incident on the sample can then be detected by a single detector or detector array and used to generate a TEM image and a STEM image.