Position correction method for rapid acquisition of transmission electron microscope

Abstract

The invention provides a position correction method for rapid acquisition of a transmission electron microscope, which is used for acquiring images of the transmission electron microscope at multiple angles. Through mathematical fitting of the relation between the image position (x, y) and the sample rod tilting angle (angle) and the relation between the focusing value (focus) and the sample rod tilting angle (angle), the position error and the focusing change caused by tilting are effectively corrected, so that the alignment precision and the imaging quality of the image are improved; according to the method, correction efficiency and automation can be greatly improved by substituting accurate numerical values into a fitting function, and the method has remarkable technical progress and application value in the aspect of improving multi-angle imaging and three-dimensional reconstruction of the transmission electron microscope.

Description

Technical Field

[0001] The invention belongs to the technical field of electron microscopes, and in particular relates to a position correction method for rapid acquisition of a transmission electron microscope. Background Art

[0002] Transmission electron microscopy (TEM) is an important scientific instrument for material research and characterization, and is widely used in materials science, biology, microelectronics and other fields. Rapid acquisition and multi-angle imaging of transmission electron microscopy are very important technical requirements in TEM characterization. Due to the limitations of precise position correction, the acquisition process is difficult to achieve automated processing.

[0003] Although the high-precision sample stage can achieve subtle displacement control, the sample position may still be offset due to mechanical errors during multi-angle acquisition. The current commercial automation system can achieve automatic sample acquisition to a certain extent through complex optical path fitting, but it is difficult to operate and has high maintenance costs, especially when frequent adjustment and calibration are required, which may cause image blur, which is a significant obstacle to subsequent image processing.

[0004] The literature J.Phys.Chem.C, 2020, 124, 27276−2728, Sci. Rep. 2015, 5, 14516. discloses the importance of fast acquisition in tomographic reconstruction, and achieves fast data acquisition and three-dimensional reconstruction through image recording and post-optimization processing of images; however, the researchers are limited to the collection of small particles within a large field of view, and during the collection process, the particles will not shift beyond the field of view; or they use manual movement and adjustment to quickly move the particles into the field of view; the position correction of these methods is not accurate enough, and the degree of automation is not high. Summary of the invention

[0005] In view of the defects and shortcomings of the prior art, the present invention proposes a position correction method for rapid acquisition of a transmission electron microscope. A fast and accurate position correction method is provided, which can be used for transmission electron microscope images during multi-angle acquisition; by mathematically fitting the relationship between the image position (horizontal coordinate x, vertical coordinate y) and the focus value focus and the sample rod tilt angle angle, the position error and focus change caused by the tilt are effectively corrected, thereby improving the alignment accuracy and imaging quality of the image; the method uses the fitting function, and accurate numerical substitution can greatly improve the correction efficiency and automation, and has significant technical progress and application value in improving the multi-angle imaging and three-dimensional reconstruction of transmission electron microscopes.

[0006] The present invention specifically adopts the following technical solutions: A method for position correction of rapid acquisition of transmission electron microscope: By tilting the electron microscope sample stage, the horizontal coordinate x, vertical coordinate y and focus value focus corresponding to the best shooting state of the electron microscope at different tilt angles are collected; The tilt angle is taken as the independent variable, the horizontal coordinate x, the vertical coordinate y, and the focus value focus are taken as the dependent variables, and the functional relationship is obtained by mathematical fitting method; The obtained functional relationship is used to correct the multi-angle shooting of the transmission electron microscope.

[0007] Further, the tilt angle is in the range of -70° to 70°.

[0008] Furthermore, the method of collecting data at different tilt angles is as follows: first, the horizontal coordinate x, the vertical coordinate y and the focus value focus of the initial optimal shooting state are all set to 0. Then adjust the sample stage to the maximum value of the tilt angle in the positive or negative direction, adjust the sample to the center of the field of view, adjust the focus value to the optimal imaging state, and record the horizontal coordinate, vertical coordinate and focus value at this time; The sample stage is tilted at a fixed step length to obtain the horizontal coordinate, vertical coordinate and focus value at the best imaging state at each angle until the maximum value of the tilt angle in the other direction is reached.

[0009] Furthermore, a polynomial function is used to fit the abscissa and the ordinate.

[0010] Furthermore, a linear function is used to fit the focus value.

[0011] And, a corresponding control system of a transmission electron microscope is characterized in that when continuously acquiring transmission electron images at different angles, a position correction program further compiled using the functional relationship obtained by the above method is run.

[0012] A transmission electron microscope adopts the control system as described above.

[0013] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a position correction program further compiled by the functional relationship obtained by the method described above is implemented.

[0014] A non-transitory computer-readable storage medium stores a computer program, which, when executed by a processor, implements a position correction program further compiled from the functional relationship obtained by the method described above.

[0015] Compared with the prior art, the present invention and its preferred embodiment provide a solution that uses angle values ​​as acquisition variables and automatically adjusts position coordinates and focusing height, which can acquire transmission images and scanning transmission images of nanoparticles with high precision.

[0016] It involves a fast acquisition position correction method, program and system device for a transmission electron microscope (TEM), which is based on a mathematical fitting method for the changes in the x, y position and focus value focus of the image as the sample rod tilt angle angle changes during multi-angle acquisition; by introducing the mathematical fitting method, the technology can accurately correct the displacement error of the sample at different tilt angles; this fitting method can significantly improve the accuracy of image alignment and reconstruction, reduce human adjustments and error accumulation, and reduce the image position deviation to less than 10% of the original error; the new correction method can process and correct data acquired at multiple angles more quickly, shortening the image processing time by more than 50%, thereby improving the overall experimental efficiency.

[0017] This method optimizes the experimental process, is easy to operate, and saves time and energy consumption required for the experiment; higher image correction accuracy provides a more reliable data basis for subsequent scientific research, which is particularly important for fine structure analysis and material research; in practical applications, this method improves the reproducibility of data and enhances the credibility of scientific conclusions. It has significant technical and economic benefits and provides strong support for multi-angle imaging research of transmission electron microscopy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 : is a comparison diagram of the offset before and after correction of the horizontal coordinate x and the vertical coordinate y of the embodiment of the present invention; Figure 2 is a comparison diagram of the offset before and after focus correction of the embodiment of the present invention; Figure 3 This is a diagram showing the effect of reducing the data acquisition time by using the automatic correction algorithm in the embodiment of the present invention; Figure 4 It is a basic implementation flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the features and advantages of this patent more obvious and easy to understand, the following embodiments are specifically described in detail as follows: It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0020] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well.

[0021] like Figure 4 As shown, the position correction method for rapid acquisition of a transmission electron microscope provided by an embodiment of the present invention, during the implementation process: The first step is to collect data points from the transmission electron microscope. The control program and module are connected to the transmission electron microscope and a suitable sample area is selected. First, when the tilt angle is 0, the electron microscope is adjusted to the best shooting state. The program records the horizontal coordinate x, vertical coordinate y, and focus value focus at this time. Tilt the electron microscope sample stage, select a suitable step length, and when the tilt angle is within a reasonable range, select a certain number of angles, record the horizontal coordinate x, vertical coordinate y, and focus value focus respectively, and obtain a series of collected data, which are then saved in the running program.

[0022] The second is the mathematical fitting method of data points; using the saved data, taking the tilt angle as the independent variable, and the horizontal coordinate x, vertical coordinate y, and focus value focus as the dependent variables, the functional relationship of horizontal coordinate x=F(angles), vertical coordinate y=G(angles), and focus value focus=H(angles) is fitted.

[0023] The obtained functional relationship is then compiled into a running program for the transmission electron microscope; the sample area to be collected is selected, the compiled program is run, the electron microscope image is automatically collected, and the image is saved.

[0024] As a preferred embodiment, the sample image can be adjusted to an optimal state at intervals of 5° within a sample stage tilt angle range of -70° to 70°.

[0025] Two embodiments are provided below to further demonstrate the scheme of the present invention and its effects: Example 1 Example of transmission electron microscopy data point collection and mathematical fitting correction: (1) At a magnification of 20,000 times, find the observation particle with a sample size of 300 nm, move the particle to the center of the field of view, adjust the sample height to the optimal imaging state, and make the focus value focus to 0. The program sets the horizontal axis to 0 and the vertical axis to 0 at this time; After adjusting the sample stage to -65°: (2) Adjust the sample to the center of the field of view, adjust the focus value to the optimal imaging state, and record the horizontal coordinate, vertical coordinate and focus value at this time; (3) Increase the sample stage angle to 65° in steps of 4°, repeat step (2), and obtain the horizontal coordinate, vertical coordinate, and focus value of each angle; (4) Fit the horizontal and vertical coordinates with a fifth-order polynomial function and fit the focus value with a linear function; (5) Apply the mathematical fitting function to position correction and observe the data offset; the offset of the horizontal and vertical coordinates is as follows: Figure 1 As shown, before correction, the x and y offsets are large, especially the y value offset exceeds 2 microns. After correction, the x and y offsets are small and can be controlled within 40nm. Figure 2 As shown, the focus value is offset by more than 3 microns before correction and less than 200nm after correction, which can meet the collection requirements of nanomaterials.

[0026] Example 2 Example of rapid collection of platinum zinc nanoparticles: (1) Apply the mathematical fitting function to the data acquisition of platinum-zinc nanoparticles. First, find the sample area to be collected, adjust the sample height to the optimal imaging state, and make the focus value focus to 0. The program sets the horizontal axis to 0 and the vertical axis to 0 at this time. (2) Run the compiled position correction function to continuously collect transmission electron images at different angles. The collection angle is -65° to 65°, the collection step is set to 1°, the rotation waiting time for each angle is set to 1 second, the collection exposure time is set to 1.5 seconds, the program relaxation time is 1.5 seconds, and the total collection time is 520 seconds; (3) Collection effect Figure 3 As shown; the acquisition time of commercial software is generally 1 to 2 hours, and the acquisition time can be controlled within 10 minutes using this program.

[0027] The above are only embodiments of the present invention. The magnification, angle selection, image size, function type, etc. are not used to limit the present invention. Professionals can understand that within the method of the present invention, modifications, equivalent substitutions, improvements, etc. made are all included in the scope of the claims of the present invention.

[0028] This patent is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of a position correction method for rapid acquisition of a transmission electron microscope under the inspiration of this patent. All equal changes and modifications made according to the scope of the patent application of the present invention should be covered by this patent.

Claims

1. A position correction method for rapid acquisition of a transmission electron microscope, characterized in that: By tilting the electron microscope sample stage, the horizontal coordinate x, vertical coordinate y and focus value focus corresponding to the best shooting state of the electron microscope at different tilt angles are collected; The tilt angle is taken as the independent variable, the horizontal coordinate x, the vertical coordinate y, and the focus value focus are taken as the dependent variables, and the functional relationship is obtained by mathematical fitting method; The obtained functional relationship is used to correct the multi-angle shooting of the transmission electron microscope.

2. A position correction method for rapid acquisition of a transmission electron microscope according to claim 1, characterized in that: The tilt angle is in the range of -70° to 70°.

3. The position correction method for rapid acquisition of a transmission electron microscope according to claim 1, characterized in that: The method of collecting data at different tilt angles is as follows: first, set the horizontal coordinate x, vertical coordinate y and focus value focus of the initial optimal shooting state to 0. Then adjust the sample stage to the maximum value of the tilt angle in the positive or negative direction, adjust the sample to the center of the field of view, adjust the focus value to the optimal imaging state, and record the horizontal coordinate, vertical coordinate and focus value at this time; The sample stage is tilted at a fixed step length to obtain the horizontal coordinate, vertical coordinate and focus value at the best imaging state at each angle until the maximum value of the tilt angle in the other direction is reached.

4. The position correction method for rapid acquisition of a transmission electron microscope according to claim 1, characterized in that: Use polynomial functions to fit the horizontal and vertical axes.

5. The position correction method for rapid acquisition of a transmission electron microscope according to claim 1, characterized in that: The focus value is fitted using a linear function.

6. A control system for a transmission electron microscope, characterized in that: When continuously acquiring transmission electron images at different angles, a position correction program further compiled using the functional relationship obtained by any one of the methods described in claims 1-5 is run.

7. A transmission electron microscope, characterized in that: A control system as claimed in claim 6 is adopted.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, it implements a position correction program further compiled from the functional relationship obtained by the method according to any one of claims 1 to 5.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements a position correction program further compiled from the functional relationship obtained by the method according to any one of claims 1 to 5.

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