1. The utility model provides a scanning electron microscope teaching model device which characterized in that: the device comprises a simulation shell (1), an electronic light path simulation system (2) and an electron microscope simulation operation system (3); the electronic light path simulation system (2) comprises a light path display part (21), a man-machine interaction liquid crystal display (22) and a control system (23); the light path display part (21) is arranged in the simulation shell (1); the human-computer interaction liquid crystal display (22) and the control system (23) are integrally installed together, are arranged outside the simulation shell (1) and are linked with the optical path display part (21) through a wire; the electron microscope simulation operation system (3) is arranged outside the simulation shell (1) and corresponds to the electronic light path simulation system (2) through a data line; the electron microscope simulation operating system can display electron microscope pictures of all standard samples related to student experiment courses.

2. The teaching model device for scanning electron microscope as claimed in claim 1, characterized in that: the simulation shell (1) is a 1:1 ratio scanning electron microscope model printed in a 3D mode, and the used material is a resin material; the lens cone part of the simulation shell (1) is cut open, so that the imaging process of a light path is conveniently displayed; the sample bin gate of the simulation shell (1) is made of transparent materials, so that the moving process of the sample and the secondary electron imaging and back scattering electron imaging processes of the sample can be observed conveniently.

3. The teaching model device for scanning electron microscope as claimed in claim 1, characterized in that: the light path display part (21) is arranged on the scanning path of the electron beam by using lamp beads, the LED lamp beads with three colors of red, green and blue are used for describing the electron beam, 3 colors can be displayed singly or combined randomly, and 7 different colors can appear.

4. A teaching model device for scanning electron microscope as claimed in claim 3, characterized in that: the lamp beads are fixedly arranged inside the simulation shell (1) according to an electron beam path.

5. The teaching model device for scanning electron microscope as claimed in claim 1, characterized in that: the optical path display part (21) can demonstrate the imaging processes of a first focusing process (211), a second focusing process (212), a post-focusing process (213), an interference part (214) and a reflection part (215) of the electron beam of the scanning electron microscope.

6. The teaching model device for scanning electron microscope as claimed in claim 1, characterized in that: the man-machine interaction liquid crystal display (22) comprises a brightness key (221), a color key (222), a light path display part key (223), a secondary electron image and back scattering electron image selection key (224) and an objective lens diaphragm selection key (225).

7. The teaching model device for scanning electron microscope as claimed in claim 6, wherein: the optical path display part key (223) can select the optical path to display the stage processes of the first focusing process (211), the second focusing process (212), the post-focusing process (213), the interference part (214) or the reflection part (215).

8. The teaching model device for scanning electron microscope as claimed in claim 6, wherein: the objective lens diaphragm selection key (225) can represent the size of the objective lens diaphragm of the scanning electron microscope through the width of the LED lamp strip; the brightness key (221) and the color key (222) can be used in a matched mode to demonstrate the energy intensity of the electron beam of the scanning electron microscope.

9. The teaching model device for scanning electron microscope as claimed in claim 1, characterized in that: the electronic light path simulation system (2) and the electron microscope simulation operation system (3) can be used in a matched mode, different materials are displayed, and the influence of different imaging modes, voltage and current parameters on the imaging quality of the scanning electron microscope image is selected.

10. The teaching model device for scanning electron microscope as claimed in claim 1, characterized in that: the electronic light path simulation system (2) can be controlled by a PLC program or a button; the electron microscope simulation operation system (3) can be connected with a computer or a projection for use.

11. A method for using a teaching model device for a scanning electron microscope as claimed in claim 1, characterized in that: electron light path analog system (2) can demonstrate scanning electron microscope's imaging process, specifically includes: the electron beam radiated from the cathode of the scanning electron microscope is focused by the first electron lens, the demonstration electron beam is focused by the second electron lens, the demonstration electron beam is focused into an extremely fine electron beam, the energy is concentrated, the resolution is improved, the demonstration is performed by the interference part, the diameter of the electron beam is adjusted, the electron beam reflected from the target material is demonstrated and is used for being absorbed by the imaging system; the specific demonstration process is as follows:

1) when the LED is electrified, automatic detection is carried out, all the LEDs are lightened once, a user control mode can be entered after no fatal fault exists, and a liquid crystal display screen has a prompt when the fault occurs;

2) the teacher can adjust the LED brightness according to the requirement by using a brightness control key (221) to adapt to the requirement of the teaching environment, the brightness is 4-level brightness when the teacher is electrified, the total 7-level brightness can be selected, and the mode is called circularly;

3) the teacher can press light path display part button (223) according to teaching progress needs and select the LED display mode, is the complete off-state after the self-checking, and the display pattern is changed once according to the display mode control key once, and the order is as follows:

no. 1 push button Lighting the primary focus 211 No. 2 key Illuminating secondary focus 212 3 rd time key Illuminating the focused back section 213 4 th time key Lighting interference 214 No. 5 key Illuminating the reflective portion 215 No. 6 key Flow lighting from top to bottom 7 th time key All-off luminescence Resume the cycle again

4) When the teacher speaks to the interference part, the teacher can directly press the special interference key (214), and at the moment, the LED of the interference part (214) lights 3 light bands to widen, and then presses once again to restore the original state;

5) when the teacher speaks of the reflection part (215), the teacher can directly press the special reflection key (215), and the backward absorption light band is lightened;

6) the teacher can press the color key (222) to randomly change the display color according to the requirement of the lecture, and the energy intensity of the electron beam at the moment can be demonstrated by matching with the brightness key (221);

7) students may complete the demonstration process under the guidance of teachers, and the students participate in the process, so that the learning effect is good, and the memory is deep, and the interactive learning process is interesting.

12. A method for using a teaching model device for a scanning electron microscope as claimed in claim 1, characterized in that: the electron microscope simulation operating system (3) can set different samples according to the requirements of experiment courses of Material analysis methods, perform test process demonstration of real samples, and perform observation effect influence on observation effects through parameters of a scanning electron microscope, wherein the parameters of the scanning electron microscope comprise voltage, current and diaphragm parameters; the specific demonstration process is as follows:

1) fixing a sample on a sample tray of a sample bin of a simulation shell (1), starting an electronic light path simulation system (2), demonstrating scanning of an electron beam on the surface of the sample, generating various different interactions with the sample, generating different signals, obtaining corresponding different microscopic images, and simultaneously starting an electronic microscope simulation operation system (3); sequentially lightening light on the light path from top to bottom, wherein the total process lasts for 3-5s, and after the light is fully lightened, displaying the acquired parameter numbers and image results; each group of parameters corresponds to different numbers and image data, and the parameters need to be loaded into a system and automatically called each time; after the light is totally bright, any parameter can be changed at any time, meanwhile, the light is changed integrally, and after 1s, the group of parameter numbers and the image data acquisition result are automatically called;

2) aiming at different samples, different diaphragm holes are selected according to an objective diaphragm selection key (225), the final tissue pictures displayed by the electron microscope simulation operation system (3) are different, the pictures are collected and implanted in a real scanning electron microscope, generally, the aperture of the diaphragm is smaller, the depth of field is larger, the resolution is higher, but the electron beam flow is reduced;

3) pressing a secondary electron image and a back scattering electron image selection key (224) to select a secondary electron image or a back scattering electron image, wherein the light paths displayed by the electron light path simulation system (2) are different, and the final images displayed by the electron microscope simulation operation system (3) are also different;

4) pressing a brightness key (221) to select different brightness levels, wherein the final images displayed by the electron microscope simulation operating system (3) are different, because the current of the condenser lens is greatly related to the image quality, and the larger the current of the condenser lens is, the higher the magnification is; meanwhile, the larger the condenser current is, the smaller the electron beam spot is, and the higher the corresponding resolution is;

5) the resolution of the scanning electron microscope is improved along with the increase of the accelerating voltage, but the contrast is reduced along with the increase of the voltage, and the pollution is serious due to overhigh accelerating voltage, so that the initial observation is generally carried out under 20kV, and then different voltage values are selected according to different purposes;

6) selection of brightness and contrast: the contrast of the secondary electron image is influenced by different secondary electron emission quantities caused by uneven surface appearance of the sample; different keys are selected on the man-machine interaction liquid crystal display (22), and the electron microscope simulation operation system (3) displays different final images.

Background

The scanning electron microscope is an important analysis and characterization tool for material major, can obtain the surface appearance, composition and structural information of materials, is an important means for researching and detecting materials, is complementary with theoretical teaching, is an important link of the whole teaching activity in the experimental teaching of the scanning electron microscope, and plays a significant role in improving the analysis and problem solving abilities of students. However, the scanning electron microscope belongs to large-scale valuable equipment, the utilization rate of the scanning electron microscope is high, and the maintenance cost is high, so that the experiment teaching matched with the scanning electron microscope mainly takes teacher explanation and demonstration operation as the main operation, the enthusiasm and creativity of students are difficult to be excited, the teaching effect is poor, and the comprehensive quality cultivation and skill exercise of college students are seriously influenced.

At present, most scanning electron microscope experiment courses in colleges and universities simply explain the principle of an electron microscope by an experimenter managing the electron microscope, and lead students to visit demonstration. Because the instrument structure is complicated, the principle is abstract and unintelligible, and because the scanning electron microscope structure is closed, students can hardly observe the inside, and no way is available for observing the effect of the electron beam and the sample, so that the students can hardly understand by oral instruction. In addition, the operation steps of the instrument are complex, the operation steps comprise sample preparation, gold spraying, sample sticking, sample loading, operation, observation, sampling and the like, each step has a place needing special attention, the experiment can not be learned by only one time, not to mention skilled operation, and even small improper operation can cause fatal damage to equipment. The number of devices and the laboratory space are limited, important parts such as an electron gun and a pole shoe of a scanning electron microscope and various probes are all under a thick shell of the device and are protected in a high-voltage vacuum state, the electron microscope cannot be disassembled and explained, so students such as secondary electron imaging and back scattering electron imaging are difficult to understand and accept, the students have little participation in a classroom and poor clinical feeling, and the students only stop understanding the scanning electron microscope on the perceptual recognition level, so that a scanning electron microscope teaching model needs to be developed for demonstrating the light path and the experimental principle of the scanning electron microscope.

Disclosure of Invention

The invention aims to provide a device of a teaching model of a scanning electron microscope, which can demonstrate the imaging principle of the scanning electron microscope, can assist in explaining the structure of the scanning electron microscope, secondary electron imaging, back-scattered electron imaging, micro-area component analysis, electron back-scattered diffraction and other functions, and solves the problems of abstract content and difficult understanding of students in the teaching process of the scanning electron microscope principle.

A teaching model device for a scanning electron microscope comprises a simulation shell, an electronic light path simulation system and an electron microscope simulation operation system; the electronic light path simulation system comprises a light path display part, a man-machine interaction liquid crystal display and a control system; the light path display part is arranged in the simulation shell; the human-computer interaction liquid crystal display and the control system are integrally installed together, are arranged outside the simulation shell and are connected with the light path display part through a lead; the electron microscope simulation operating system is arranged outside the simulation shell and corresponds to the electronic light path simulation system through a data line; the electron microscope simulation operating system can display electron microscope pictures of all standard samples related to student experiment courses.

Further, the simulation shell is a 3D printed 1:1 ratio scanning electron microscope model, and the used material is a resin material; the lens cone part of the simulation shell is cut open, so that the imaging process of a light path is conveniently displayed; the sample bin gate of the simulation shell is made of transparent materials, so that the moving process of the sample and the secondary electron imaging and back scattering electron imaging processes of the sample can be observed conveniently.

Furthermore, the light path display part is formed by arranging lamp beads on the scanning path of the electron beam, red, green and blue LED lamp beads are used for describing the electron beam, 3 colors can be displayed singly or combined randomly, and 7 different colors can appear.

Furthermore, the lamp beads are fixedly installed inside the simulation shell according to the path of the electron beam.

Furthermore, the light path display part can demonstrate the imaging processes of a first focusing process, a second focusing process, a process after focusing, an interference part and a reflection part of the scanning electron microscope electron beam.

Further, the man-machine interaction liquid crystal display comprises a brightness key, a color key, a light path display part key, a secondary electron image and back scattering electron image selection key and an objective lens diaphragm selection key.

Further, the optical path display part key can select the optical path to display the stage processes of the first focusing process, the second focusing process, the focused process, the interference part or the reflection part.

Further, the size of the objective diaphragm of the scanning electron microscope can be represented by the width of the LED lamp strip through the objective diaphragm selection key; the brightness key and the color key can be used in a matched mode to demonstrate the energy intensity of the electron beam of the scanning electron microscope.

Furthermore, the electronic light path simulation system and the electron microscope simulation operating system can be used in a matched manner, different materials are displayed, and the influence of different imaging modes, voltage and current parameters on the imaging quality of the scanning electron microscope image is selected.

Further, the electronic light path simulation system can be controlled by a program through a PLC or a button; the electron microscope simulation operation system (3) can be connected with a computer or a projection for use.

The application method of the teaching model device for the scanning electron microscope is characterized by comprising the following steps: electron light path analog system can demonstrate scanning electron microscope's imaging process, specifically includes: the electron beam radiated from the cathode of the scanning electron microscope is focused by the first electron lens, the demonstration electron beam is focused by the second electron lens, the demonstration electron beam is focused into an extremely fine electron beam, the energy is concentrated, the resolution is improved, the demonstration is performed by the interference part, the diameter of the electron beam is adjusted, the electron beam reflected from the target material is demonstrated and is used for being absorbed by the imaging system; the specific demonstration process is as follows:

1) when the LED is electrified, automatic detection is carried out, all the LEDs are lightened once, a user control mode can be entered after no fatal fault exists, and a liquid crystal display screen has a prompt when the fault occurs;

2) the teacher can adjust the LED brightness according to the requirement by using the brightness control key to adapt to the requirement of the teaching environment, the brightness is 4-level brightness when the teacher is electrified, the total 7-level brightness can be selected, and the mode is called circularly;

3) the teacher can press light path display part button (223) according to teaching progress needs and select the LED display mode, is the complete off-state after the self-checking, and the display pattern is changed once according to the display mode control key once, and the order is as follows:

no. 1 push button	Lighting the primary focus 211
			No. 2 key	Illuminating secondary focus 212
3 rd time key	Illuminating the focused back section 213
			4 th time key	Lighting interference 214
No. 5 key	Illuminating the reflective portion 215
			No. 6 key	Flow lighting from top to bottom
7 th time key	All-off luminescence	Resume the cycle again

4) When the teacher speaks to the interference part, the teacher can directly press the special interference key (214), and at the moment, the LED of the interference part (214) lights 3 light bands to widen, and then presses once again to restore the original state;

5) when the teacher speaks of the reflection part (215), the teacher can directly press the special reflection key (215), and the backward absorption light band is lightened;

6) the teacher can press the color key (222) to randomly change the display color according to the requirement of the lecture, and the energy intensity of the electron beam at the moment can be demonstrated by matching with the brightness key (221);

7) students may complete the demonstration process under the guidance of teachers, and the students participate in the process, so that the learning effect is good, and the memory is deep, and the interactive learning process is interesting.

The application method of the teaching model device for the scanning electron microscope is characterized by comprising the following steps: the electron microscope simulation operating system can set different samples according to the requirements of experiment courses of Material analysis method, perform test process demonstration of real samples, and influence the observation effect by the parameters of a scanning electron microscope, wherein the parameters of the scanning electron microscope comprise voltage, current and diaphragm parameters; the specific demonstration process is as follows:

1) fixing the sample on a sample tray of a sample bin of the simulation shell, starting an electronic light path simulation system, demonstrating scanning of an electron beam on the surface of the sample, generating various different interactions with the sample to generate different signals, obtaining corresponding different microscopic images, and simultaneously starting an electronic microscope simulation operation system; sequentially lightening light on the light path from top to bottom, wherein the total process lasts for 3-5s, and after the light is fully lightened, displaying the acquired parameter numbers and image results; each group of parameters corresponds to different numbers and image data, and the parameters need to be loaded into a system and automatically called each time; after the light is totally bright, any parameter can be changed at any time, meanwhile, the light is changed integrally, and after 1s, the group of parameter numbers and the image data acquisition result are automatically called;

2) aiming at different samples, different diaphragm holes are selected by pressing an objective diaphragm selection key, and the final organization pictures displayed by the electron microscope simulation operation system are different and are collected and implanted in the real scanning electron microscope, wherein the smaller the aperture of the diaphragm is, the larger the depth of field is, the higher the resolution is, but the electron beam flow is reduced;

3) selecting a secondary electron image or a back scattering electron image according to a secondary electron image and back scattering electron image selection key, wherein the light paths displayed by the electron light path simulation system are different, and the final images displayed by the electron microscope simulation operation system are also different;

4) pressing a brightness key to select different brightness levels, wherein the final images displayed by the electron microscope simulation operation system are different, because the current of the condenser lens has a great relationship with the image quality, the larger the current of the condenser lens is, the higher the magnification is; meanwhile, the larger the condenser current is, the smaller the electron beam spot is, and the higher the corresponding resolution is;

5) the resolution of the scanning electron microscope is improved along with the increase of the accelerating voltage, but the contrast is reduced along with the increase of the voltage, and the pollution is serious due to overhigh accelerating voltage, so that the initial observation is generally carried out under 20kV, and then different voltage values are selected according to different purposes;

6) selection of brightness and contrast: the contrast of the secondary electron image is influenced by different secondary electron emission quantities caused by uneven surface appearance of the sample; different keys are selected on the man-machine interaction liquid crystal display, and the electron microscope simulation operation system displays different final images.

The technical scheme of the invention has the following advantages:

1) according to the device for the teaching model of the scanning electron microscope, provided by the invention, an electron microscope simulation operating system is built by abundant multimedia means, a plurality of sets of scanning electron microscope models are manufactured by using a 3D printing technology, students have experience of computer practice, a method for scientifically researching by using an electron microscope is mastered, and meanwhile, the learning of theoretical knowledge and experimental lessons can be uniformly completed by electron microscope experimental lessons which need to be explained in groups in the past, so that the teaching efficiency is improved.

2) According to the device for the teaching model of the scanning electron microscope, provided by the invention, the light path diagram and the circuit board system simulating the working principle of the electron beam in the electron microscope are built, so that students can visually know the working principle of the electron microscope, and the working principle of the electron microscope can be more clearly known by matching with the dissected scanning electron microscope.

3) The device of the teaching model of the scanning electron microscope provided by the invention not only can demonstrate the whole process from generating signals to receiving signals of the electron beam of the scanning electron microscope, but also can demonstrate the influence of different parameters such as voltage, objective lens diaphragm and current on a light source and the influence of different parameter selections on the imaging effect of a sample, and the whole device is portable and convenient to carry and is suitable for the application of relevant courses of scanning electron microscopes in colleges and universities.

4) The device for scanning the electron microscope teaching model provided by the invention adds a manual practice link for students in an experimental course, so that the students can take pictures of interested parts in a sample and fully arouse the interest and independence of the students, rather than performing mechanized tests according to the arranged requirements.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic view of a teaching model of a scanning electron microscope according to the present invention;

FIG. 2 is a schematic view of a light path display part of the device for teaching a scanning electron microscope according to the present invention;

FIG. 3 is a schematic view of a human-computer interaction LCD of the device for teaching a scanning electron microscope according to the present invention.

Description of reference numerals:

1-a simulation shell; 2-an electronic light path simulation system; 3-simulating an operating system by an electron microscope; 21-an optical path display section; 22-human-computer interaction liquid crystal display; 23-a control system; 211-first focusing process; 212-second focusing process; 213-post-focusing process; 214-an interference portion; 215-a reflective portion; 221-brightness key; 222-color keys; 223-light path display part key; 224-secondary and backscattered electron image selection buttons; 225-objective stop selection button.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1, a teaching model device for a scanning electron microscope includes a simulation housing 1, an electronic light path simulation system 2 and an electron microscope simulation operation system 3; the electronic light path simulation system 2 comprises a light path display part 21, a man-machine interaction liquid crystal display 22, a control system 23 and the like; the light path display part 21 is installed inside the simulation case 1; the human-computer interaction liquid crystal display 22 and the control system 23 are integrally installed together, are arranged outside the simulation shell 1 and are connected with the light path display part 21 through a lead; the electron microscope simulation operating system 3 is arranged outside the simulation shell 1 and corresponds to the electronic light path simulation system 2 through a data line; the electron microscope simulation operating system can display electron microscope pictures of all standard samples related to student experiment courses.

The simulation shell 1 is a 3D printed 1:1 ratio scanning electron microscope model, the used material is a resin material, and the lens cone part of the simulation shell 1 is cut open, so that the imaging process of a light path is conveniently displayed; the sample bin gate of the simulation shell 1 is made of transparent materials, so that the moving process of the sample and the secondary electron imaging and back scattering electron imaging processes of the sample can be observed conveniently.

As shown in fig. 2, the electron light path simulation system 2 uses the LED light emitting tube to simulate the electron beam path and the operation form of the electron microscope, so that teachers can conveniently explain the electron beam path and the operation form in teaching, students can easily understand the working process and principle of the electron microscope, and a good foundation is laid for the students to better master the use of the electron microscope.

The light path display part 21 is arranged on the path of the scanning of the electron beam by using lamp beads and consists of a PCB (printed circuit board), a light emitting diode array and a digital logic control part. The full-color LED tube for display is an integrated tube with three colors of red, green and blue, so that 7 colors can be displayed, and teachers can conveniently distinguish the electronic working intensity states according to the colors. The full-color LDE tube can be displayed step by step from top to bottom after being controlled, and the full-color LDE tube is matched with the explanation progress of a teacher. And the dynamic display can be realized in an integral up-down flowing mode, so that the students can be intuitively informed of the electron beam advancing state. The PCB and the software environment for manufacturing the PCB are both made in China and are independently controllable. The full-color LDE control mode is flexible, and the subsequent upgrading display mode is convenient.

As shown in fig. 1, the lamp beads are fixedly installed inside the simulation housing 1 according to an electron beam path.

As shown in fig. 2, the optical path display part 21 can demonstrate the imaging processes of the first focusing process 211, the second focusing process 212, the post-focusing process 213, the interference part 214 and the reflection part 215 of the sem electron beam.

As shown in fig. 3, the human-computer interaction liquid crystal display 22 includes a brightness key 221, a color key 222, a light path display portion key 223, a secondary electron image and backscattered electron image selection key 224, and an objective lens stop selection key 225.

The optical path display part button 223 can select the stage process of the optical path display first focusing process 211, second focusing process 212, post-focusing process 213, interference part 214, or reflection part 215.

The objective diaphragm selection key 225 can represent the size of the objective diaphragm of the scanning electron microscope by the width of the LED lamp strip; the brightness key 221 and the color key 222 can be used in cooperation to demonstrate the energy intensity of the electron beam of the scanning electron microscope.

The electronic light path simulation system 2 and the electron microscope simulation operating system 3 can be used in a matched mode to display different materials, and the influence of parameters such as different imaging modes, voltage and current on the imaging quality of the scanning electron microscope image is selected.

The electronic light path simulation system 2 can use a PLC to perform program control or perform control through a button; the electron microscope simulation operation system 3 can be connected with a computer or a projection for use.

The control system 23 of the electronic optical circuit simulation system 2 is integrated with the power supply part and the man-machine interaction display screen 22 in a case. The control system 23 uses industrial PIC single chip as central control element, the element is embedded with control system software, and has rich functions, high reliability, no connection with network and no attack, controllable risk, easy acquisition (domestic production), and can be replaced by domestic STC single chip in extreme cases.

Electron light path analog system 2 can demonstrate scanning electron microscope's imaging process, specifically includes: the electron beam radiated from the cathode of the scanning electron microscope is focused by the first electron lens, the demonstration electron beam is focused by the second electron lens, the demonstration electron beam is focused into an extremely fine electron beam, the energy is concentrated, the resolution is improved, the demonstration is performed by the interference part, the diameter of the electron beam is adjusted, the electron beam reflected from the target material is demonstrated, and the electron beam is absorbed by the imaging system. The specific demonstration process is as follows:

1. when the LED lamp is powered on, automatic detection is carried out, all the LEDs are lightened once, and the LED lamp can enter a user control mode (a prompt is provided on a liquid crystal display screen when a fault occurs) after no fatal fault exists.

2. The teacher can adjust the LED brightness according to the requirement by using the brightness control key 221 to adapt to the requirement of the teaching environment, the brightness is 4-level brightness when the teacher is electrified, the total 7-level brightness can be selected, and the mode is called circularly.

3. The teacher can press light path display part button 223 according to teaching progress needs and select the LED display mode, and for putting out the state entirely after the self-checking, every time changes once according to the display mode control key and shows the figure, the order is as follows:

no. 1 push button	Lighting the primary focus 211
			No. 2 key	Illuminating secondary focus 212
3 rd time key	Illuminating the focused back section 213
			4 th time key	Lighting interference 214
No. 5 key	Illuminating the reflective portion 215
			No. 6 key	Flow lighting from top to bottom
7 th time key	All-off luminescence	Resume the cycle again

4. When the teacher speaks to the interference part, he can directly press the special interference key 214, at this time, the LED of the interference part 214 lights 3 light bands to widen, and then presses again to restore the original state.

5. When the teacher speaks of the reflective portion 215, he or she can press the dedicated reflective key 215 directly, whereupon the backward absorbing light band lights up.

6. The teacher can press the color key 222 to display any color according to the requirement of lecture, and the brightness key 221 is matched to use the energy intensity which can demonstrate the electron beam at the moment.

7. The students can complete the demonstration process under the guidance of the teacher, and the students participate in the demonstration process, so that the demonstration process has good learning effect and deep memory, and the interactive learning process is interesting.

The electron microscope simulation operating system 3 may set different samples according to the requirements of the experimental course of "material analysis method", and perform the test process demonstration of the real sample, for example, the experimental sample is a TC4 alloy (mosaic) sample, and the imaging process of the solid sample is demonstrated, including the influence of the parameters of the scanning electron microscope (such as voltage, current, diaphragm, and the like) on the observation effect. The specific demonstration process is as follows:

1. fixing a sample on a sample tray of a sample chamber of the simulation shell 1, starting the electronic light path simulation system 2, demonstrating scanning of an electron beam on the surface of the sample, generating various different interactions with the sample to generate different signals, obtaining corresponding different microscopic images, and simultaneously starting the electron microscope simulation operation system 3. And sequentially lightening light on the light path from top to bottom, wherein the total process lasts for 3-5s, and after the light is fully lightened, displaying the acquired parameter numbers and the image results. Each group of parameters corresponds to different numbers and image data, and the parameters need to be loaded into the system and automatically called each time. After the light is totally bright, any parameter can be changed at any time, and the light changes integrally at the same time, and the group of parameter numbers and the image data acquisition result are automatically called after 1 s.

2. For a TC4 alloy sample, different diaphragm holes are selected by pressing an objective diaphragm selection button 225, the final organization pictures displayed by the electron microscope simulation operating system 3 are different, the pictures are collected and implanted in a real scanning electron microscope, generally, the aperture of the diaphragm is smaller, the depth of field is larger, the resolution is higher, but the electron beam flow is reduced.

3. The secondary electron image or the backscattered electron image is selected by pressing the secondary electron image and backscattered electron image selection button 224, the light paths displayed by the electron light path simulation system 2 are different, and the final images displayed by the electron microscope simulation operation system 3 are also different.

4. Pressing the brightness button 221 selects different brightness levels, and the final image displayed by the electron microscope simulation operating system 3 is also different because the condenser current has a large relationship with the image quality, and the larger the condenser current is, the higher the magnification is. Meanwhile, the larger the condenser current is, the smaller the electron beam spot is, and the higher the corresponding resolution is.

5. The resolution of the scanning electron microscope is improved along with the increase of the accelerating voltage, but the contrast is reduced along with the increase of the voltage, and the pollution is serious due to the overhigh accelerating voltage, so that the initial observation is generally carried out under 20kV, and then different voltage values are selected according to different purposes.

6. Selection of brightness and contrast: the contrast of the secondary electron image is affected by the difference in the number of secondary electron emissions caused by the uneven surface topography of the sample. When different keys are selected on the man-machine interaction liquid crystal display 22, the electron microscope simulation operating system 3 displays different final images.

Through different parameters and the arrangement of the detector, students can deepen the understanding of the resolution and the depth of field and understand secondary electron surface morphology images and backscattered electron atomic number images. And an intelligent heuristic guidance function is set in each step to inspire students and guide the students to operate and drill according to the correct steps. Through the field operation exercise, carry out the analysis to different samples, the student can form rational understanding to scanning electron microscope operation, lets the student improve the analysis ability in the practice, understands the classroom teaching content that relates. The examples are used to enhance the understanding of different image features, especially secondary and backscattered electron images, to enhance the understanding of resolution and depth of field. In the sample testing process, the adjustment of astigmatism is an important and tedious operation, so that students can be guided to judge the existence of astigmatism and a method for eliminating astigmatism by themselves, and meanwhile, key points and attention points are explained, and the understanding and comprehension of the students on scanning electron microscope instruments are deepened.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.