Electron Microscope Phase Plate Unevenness Compensation

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Solution Overview

Problem

Existing electron microscopes with hole-free phase plates can capture images with false contrast due to unevenness in the phase plate, which affects the quality of the TEM images obtained.

Innovation Solution

An electron microscope system that includes a control unit to acquire a phase plate image, determine the presence of unevenness, and move the phase plate to avoid affected areas, ensuring that the electron beam falls on even regions for optimal imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a hole-free phase plate is used to change the phases of transmitted and scattered waves, then high contrast imaging of light elements is achieved, but false contrast appears in TEM images due to unevenness in the phase plate

Engineering Contradiction:
Improveimage contrastVSAvoidimage accuracy
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The phase plate is made movable relative to the electron beam path. The moving mechanism allows the phase plate to be dynamically repositioned to different locations, enabling the system to adapt to and compensate for unevenness in the phase plate structure by selecting optimal imaging regions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A control unit acts as an intermediary between the detection system and the moving mechanism. It processes phase plate images to detect unevenness and automatically controls the moving mechanism to reposition the phase plate, eliminating the need for manual intervention and ensuring accurate compensation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the phase plate is stationary, then the system structure is simple, but uneven areas on the phase plate cannot be avoided

Engineering Contradiction:
Improvesystem structureVSAvoidimage quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The phase plate is made movable relative to the electron beam path. The moving mechanism allows the phase plate to be dynamically repositioned to different locations, enabling the system to adapt to and compensate for unevenness in the phase plate structure by selecting optimal imaging regions.

Inventive Principle:
Principle #15Dynamics

3Reliability

If manual inspection and adjustment of the phase plate is performed, then unevenness can be detected and corrected, but the process is time-consuming and reduces productivity

Engineering Contradiction:
Improveimage qualityVSAvoidimaging efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

A control unit acts as an intermediary between the detection system and the moving mechanism. It processes phase plate images to detect unevenness and automatically controls the moving mechanism to reposition the phase plate, eliminating the need for manual intervention and ensuring accurate compensation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs self-diagnosis and self-correction by automatically detecting phase plate unevenness through image processing and autonomously controlling the moving mechanism to reposition the phase plate to optimal locations, without requiring external manual operation.

Inventive Principle:
Principle #25Self-service

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 approach allows for the acquisition of satisfactory electron microscope images by avoiding uneven areas on the phase plate, thereby improving image quality and maintaining the phase plate's functionality.

Implementation Method 1

The phase plate changes the phase of an electron wave. The phase plate is disposed, for example, at the back focal plane of an objective lens to change the phases of a transmitted wave and a scattered wave relative to each other. By causing interference of the transmitted wave and scattered wave that underwent such relative phase change, a sample including a large amount of light elements can be observed with high contrast.

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

By causing interference of the transmitted wave and scattered wave that underwent such relative phase change, a sample including a large amount of light elements can be observed with high contrast.

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

In the hole-free phase plate, no hole is provided in the thin film, and the phases of the transmitted wave and the scattered wave are changed relative to each other as a result of the transmitted wave and the scattered wave passing through the thin film. In the hole-free phase plate, the phases of the transmitted wave and the scattered wave are changed relative to each other by partially charging the thin film by an electron beam.

Methodology Applied
Scientific EffectElectron beam charging: Electron Beam

Data Source

PatentEP3591686B1Electron microscope
Publication Date: 2021.03.24 JEOL LTD
  • EP3591686B1 patent drawingFigure 1
  • EP3591686B1 patent drawingFigure 2
  • EP3591686B1 patent drawingFigure 3~4

AI summary

An electron microscope (100) comprises: an electron microscope main body (10) including a phase plate (15) that imparts a phase change to an electron wave, a moving mechanism (16) that moves the phase plate (15), and a detector (19) that acquires an image formed by an electron beam transmitted through a sample (S); and a control unit (20) that controls the electron microscope main body (10). The control unit (20) performs a phase plate image acquisition process of acquiring a phase plate image which is an image of the phase plate (15); an unevenness determination process of determining whether or not the phase plate (15) has unevenness based on the phase plate image; and a moving mechanism control process of moving the phase plate (15) by controlling the moving mechanism (16) when the control unit (20) has determined that the unevenness is present.