A sample stage for scanning electron microscope testing

Abstract

The present invention relates to a sample stage for scanning electron microscope testing, comprising a base, a supporting part, three movable clamping parts and an anti-collision positioning assembly, a supporting column is provided in the center of the lower surface of the base, and the supporting column is inserted into the through hole of the original sample stage of the scanning electron microscope; three horizontally arranged tension springs are provided on the base and are evenly distributed in a radial shape, and the horizontal plate at the bottom of the clamping part is connected to the base through the tension spring, so that the clamping part can move back and forth along the radial direction of the base to expand or reduce the size of the bottom surface of the sample stage; the vertical rod and the supporting part of the clamping part are both vertical, and the supporting part is detachably plugged in the center of the circle of the base, and a coal sample can be placed between a vertical rod and the supporting part; the anti-collision positioning assembly comprises an anti-collision frame and a limit rod, the bottom of the anti-collision frame is connected to the tops of the three vertical rods, a sensor is installed on the anti-collision frame, and the limit rod is installed on the side of the probe, when the sensor senses the limit rod, the original sample stage stops moving up to prevent the coal sample from colliding with the probe.

Description

Technical Field

[0001] The invention belongs to the technical field of scanning electron microscope sample stages, and in particular relates to a sample stage for scanning electron microscope testing. Background Art

[0002] The scanning electron microscope (SEM) is a high-precision imaging device. During use, a removable, original sample stage is located below the probe. This stage is evenly distributed with through-holes. The sample is fixed to the stage, and the position of the stage is adjusted so that the sample is directly below the probe (lens). The stage is then controlled to move upward. The optimal observation position is when the top surface of the sample is 10 mm from the probe, which provides the clearest image. However, manual adjustment of the sample stage can result in significant errors, and the 10 mm distance is too small. If care is not taken, the stage can move too far, causing the sample to hit the probe, which can easily damage the probe and cause serious economic losses. Summary of the Invention

[0003] To address the above problems, the present invention provides a sample stage for scanning electron microscope testing, comprising a base, a support portion, three movable clamping portions, and an anti-collision positioning assembly. A support column is provided in the center of the lower surface of the base, and the support column can be inserted into a through hole of the original sample stage of the scanning electron microscope, so that the base is stably placed on the original sample stage.

[0004] The base is equipped with three horizontally arranged tension springs that are evenly distributed in a radial pattern. The horizontal plate at the bottom of the clamping part is connected to the base through the tension springs, so that the clamping part can move back and forth along the radial direction of the base to expand or reduce the size of the bottom surface of the sample stage.

[0005] The vertical rod and the supporting part of the clamping part are both vertical. The supporting part is detachably plugged into the center of the base. A coal sample can be placed between one vertical rod and the supporting part.

[0006] The anti-collision positioning assembly includes an anti-collision frame and a limit rod. The bottom of the anti-collision frame is connected to the top of the three vertical rods. The sensor is installed on the anti-collision frame and the limit rod is installed on the side of the probe. When the sensor senses the limit rod, the original sample table stops moving up to prevent the coal sample from colliding with the probe.

[0007] The sample stage of the present invention has a retractable clamping portion, but when the clamping portion moves radially toward the outside of the base, the accommodating space of the sample stage can be expanded. At the same time, in conjunction with the support portion at the center of the base, three coal samples can be placed. The two sides of each coal sample are clamped and positioned by the vertical rod and the support portion, respectively, so that three coal samples can be placed at the same time for one test, which is more efficient. The present invention does not require changing the structure of the existing scanning electron microscope. The limit rod can be used as an accessory and bonded to the side of the probe without affecting the operation of the probe. The limit rod can also be removed when not needed. The sample stage of the present invention is in a detachable plug-in relationship with the original sample stage of the scanning electron microscope, which does not affect the structure and other uses of the original sample stage, and the sample stage of the present invention can move with the original sample stage. The cooperation of the limit rod and the limit sensor can determine the timing when the original sample stage and the sample stage stop moving upward, thereby preventing the top surface of the coal sample from hitting the probe and avoiding the defect of manually judging the timing of stopping moving upward.

[0008] Samples tested under a scanning electron microscope (SEM) are typically pre-sprayed with gold to enhance conductivity and facilitate clear imaging. The standard SEM sample stage is pre-installed inside the microscope, making it inconvenient to disassemble and assemble. During experimental testing, a small, custom-made sample stage (a circular base with supporting columns) is typically constructed. The sample is attached to the stage with double-sided tape, sprayed with gold in a dedicated device, and then placed on the standard stage for testing. Some samples can be made into small blocks or slices (a few millimeters in size). However, coal samples are unique. Some are cut from larger blocks and then ground, while others are formed by pressing coal powder. Consequently, coal samples have a fixed shape. Coal samples commonly used in the coal and geological fields are cylindrical, with parallel, polished top and bottom surfaces, allowing the sample to stand upright on the stage (1-3 cm in height and 2-3 cm in diameter). This makes existing small sample stands unsuitable. First, due to their size limitations, only one coal sample can be tested at a time, resulting in low testing efficiency. Second, vertical coal samples are only bonded at the bottom, making them unstable and prone to tipping over during spraying and testing, potentially knocking over other samples. Therefore, the present invention has designed a sample stand specifically for coal samples.

[0009] Optionally, the base is circular, and the upper surface of the base is provided with three grooves, which are evenly distributed in a radial pattern, and the grooves are recessed toward the base, for accommodating the transverse plate and the tension spring; a first threaded hole is provided in the center of the base for connecting the support portion;

[0010] The clamping part is L-shaped and includes a horizontal plate, a vertical rod and an edge positioning component. One end of the horizontal plate is connected to the tension spring, and the other end is connected to the bottom of the vertical rod. A second threaded hole is provided in the vertical rod for connecting the edge positioning component; the top of the edge positioning component is provided with a straight overlapping edge extending outward, which is used to support the top surface of the coal sample close to the vertical rod.

[0011] Further optionally, an inner wall of the first threaded hole is provided with an internal thread, the first threaded hole is concentrically arranged with the base, and the top surface of the first threaded hole is flush with the upper surface of the base;

[0012] The support part is a vertical rod, and a circular chassis is fixedly connected to the outer wall of the support part. The chassis has the same diameter as the base and is used to cover the upper surface of the base; the part of the support part below the chassis is cylindrical, and the outer wall of the part is provided with an external thread for connecting to the first threaded hole; the part of the support part above the chassis is triangular prism, and the three side faces are used to connect three coal samples respectively.

[0013] Further optionally, the top end of the vertical rod is open and recessed inwardly to form a second threaded hole, and the inner wall of the second threaded hole is provided with an internal thread; the edge positioning component includes a circular overlapped edge 1 at the top and an edge positioning pin below the overlapped edge 1, and the outer side surface of the edge positioning pin is provided with an external thread;

[0014] After placing the coal sample, the edge positioning nail is screwed into the second threaded hole and threaded until the lower surface of the overlap contacts the top surface of the coal sample. The edge positioning nail is stopped from being screwed in, thereby positioning the height of the top surface of the coal sample.

[0015] Further optionally, the top end of the support portion is open and recessed inwardly to form a third threaded hole, and the inner wall of the third threaded hole is provided with an internal thread; the middle positioning component includes a circular overlapped edge 2 at the top and a middle positioning pin below the overlapped edge 2, and the outer side surface of the middle positioning pin is provided with an external thread;

[0016] After placing the three coal samples, the middle positioning nail is screwed into the third threaded hole and threaded until the lower surface of the second overlap contacts the top surfaces of the three coal samples. Then, the middle positioning nail is stopped from being screwed in, thereby positioning the height of the top surfaces of the three coal samples.

[0017] Optionally, the anti-collision frame includes an upper support ring, a lower support ring and three support rods, the upper support ring is concentrically arranged with the lower support ring, and the three support rods are evenly arranged along the circumference of the upper support ring; the bottom of the support rod is connected to the top surface of the edge positioning component of the corresponding vertical rod, the top of the support rod is detachably connected to the upper support ring, and the lower part of the support rod is detachably connected to the lower support ring;

[0018] The sensor is installed on the upper support ring. The vertical distance between the upper support ring and the lower support ring is fixed. By designing the installation position of the limit rod on the side of the probe and the vertical distance between the upper and lower support rings, when the sensor senses the limit rod, the distance between the bottom end of the probe and the top surface of the coal sample reaches the optimal observation distance (i.e. 10 mm).

[0019] Further optionally, the support rod is divided into upper and lower parts with the position where it is connected to the lower support ring as the dividing line, the upper part is an inclined rod connected between the upper and lower support rings, and the lower part is a vertical rod connected between the side positioning component and the lower support ring; the bottom end of the lower part of the support rod is bonded to the top surface of the side positioning component.

[0020] Further optionally, the diameter of the lower support ring is equal to the diameter of the circle surrounded by the three vertical rods, and the diameter of the upper support ring is larger than that of the lower support ring; and washers are bonded to the inner sides of the upper and lower support rings.

[0021] Further optionally, the lower support ring is a circle formed by the intersection of two ends of a rod. By adjusting the length of the overlapping part of the two ends of the rod, the diameter of the lower support ring can be adjusted to accommodate coal samples of different diameters.

[0022] Further optionally, the sensor is installed on the upper support ring through a support, the support is concave, and the support is parallel to the tangent direction of the position where the support is installed on the upper support ring; the groove in the middle of the support has two opposite side surfaces and a bottom surface, and the sensor is installed on one of the side surfaces. When the sensor rises with the sample stage and approaches the limit rod, the limit rod enters the groove of the support and blocks the front of the sensor, the sensor senses the limit rod and transmits the signal to the control mechanism that controls the movement of the original sample stage, pausing the upward movement of the original sample stage. At this time, the bottom end of the probe is 10 mm away from the top surface of the coal sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of the sample stage for scanning electron microscope testing;

[0024] Figure 2 A schematic diagram of the support portion connected to the base;

[0025] Figure 3 A schematic diagram of the connection between the support portion and the middle positioning component;

[0026] Figure 4 This is a schematic diagram of the crash bar (the support is omitted);

[0027] Figure 5 This is a schematic diagram of the support sensing the limit rod;

[0028] Figure 6 for Figure 5 Schematic side view of .

[0029] In the accompanying drawings, 1-base, 2-support part, 3-clamping part, 4-support column, 5-tension spring, 6-horizontal plate, 7-vertical rod, 8-anti-collision frame, 9-limiting rod, 10-sensor, 11-groove, 12-first threaded hole, 13-side positioning component, 14-overlapping side one, 15-overlapping side two, 16-chassis, 17-middle positioning component, 18-upper support ring, 19-lower support ring, 20-support rod, 21-support. DETAILED DESCRIPTION

[0030] This embodiment provides a sample stage for scanning electron microscope testing, such as Figures 1-6 As shown, it includes a base 1, a support part 2, three movable clamping parts 3 and an anti-collision positioning component. A support column 4 is provided in the center of the lower surface of the base 1. The support column 4 can be inserted into the through hole of the original sample stage of the scanning electron microscope, so that the base 1 is stably placed on the original sample stage;

[0031] The base 1 is provided with three horizontally arranged tension springs 5, which are evenly distributed in a radial pattern. The horizontal plate 6 at the bottom of the clamping portion 3 is connected to the base 1 through the tension springs 5, so that the clamping portion 3 can move back and forth along the radial direction of the base 1 to expand or reduce the size of the bottom surface of the sample stage;

[0032] The vertical rod 7 of the clamping part 3 and the support part 2 are both vertical. The support part 2 is detachably plugged into the center of the base 1. A coal sample can be placed between one vertical rod 7 and the support part 2.

[0033] The anti-collision positioning assembly includes an anti-collision frame 8 and a limit rod 9. The bottom of the anti-collision frame 8 is connected to the top of the three vertical rods 7. A sensor 10 is installed on the anti-collision frame 8, and the limit rod 9 is installed on the side of the probe. When the sensor 10 senses the limit rod 9, the original sample platform stops moving up to prevent the coal sample from colliding with the probe.

[0034] Optionally, the base 1 is circular, and three grooves 11 are provided on the upper surface of the base 1, which are evenly distributed in a radial pattern. The grooves 11 are recessed toward the base 1 and are used to accommodate the transverse plate 6 and the tension spring 5. A first threaded hole 12 is provided in the center of the base 1 for connecting to the support portion 2, and the starting ends of the three grooves 11 begin from the outer wall of the first threaded hole 12.

[0035] The clamping portion 3 is L-shaped and includes a horizontal plate 6, a vertical rod 7 and an edge positioning component 13. One end of the horizontal plate 6 is connected to the tension spring 5, and the other end is connected to the bottom of the vertical rod 7. A second threaded hole is provided in the vertical rod 7 for connecting the edge positioning component 13; the top of the edge positioning component 13 is provided with a flat overlapping edge 14 extending outward and protruding, which is used to support the top surface of the coal sample close to the vertical rod 7.

[0036] Further optionally, the base 1 has a certain thickness, which can be determined according to actual needs, for example, 0.5-1.5 cm or larger; the diameter of the tension spring 5 is not greater than the depth of the corresponding groove 11, and the thickness of the cross plate 6 is slightly smaller than the depth of the groove 11, so that the tension spring 5 and the cross plate 6 can move in the groove 11.

[0037] Further optionally, the inner wall of the first threaded hole 12 is provided with an internal thread, the first threaded hole 12 is concentrically arranged with the base 1, and the top surface of the first threaded hole 12 is flush with the upper surface of the base 1 and higher than the bottom surface of the groove;

[0038] The support part 2 is a vertical rod, and a circular chassis 16 is fixedly connected to the outer wall of the support part 2. The chassis 16 has the same diameter as the base 1 and is used to cover the upper surface of the base 1; the part of the support part 2 below the chassis 16 is cylindrical, and the outer wall of the part is provided with an external thread for connecting to the first threaded hole 12; the part of the support part 2 above the chassis 16 is a triangular prism, and the three side faces are used to connect three coal samples respectively.

[0039] The chassis 16 and the base 1 are detachable, which is convenient for maintenance and replacement of the tension spring 5. The way of connecting the two ends of the tension spring 5 to the first threaded hole 12 and the cross plate 6 can adopt various forms. For example, a pull ring is provided on the outer wall of the first threaded hole 12 at the position corresponding to the tension spring 5, and a pull ring is provided at one end of the cross plate 6 at the position corresponding to the tension spring 5 for connecting the tension spring 5. The cross plate 6 can be a flat rectangular parallelepiped, and the groove serves as a movable track corresponding to the cross plate 6. After the tension spring 5 and the clamping part 3 are installed, the bottom of the support part 2 is inserted into the first threaded hole 12 and threadedly connected to the first threaded hole 12, so that the lower surface of the chassis 16 contacts the upper surface of the base 1, that is, the chassis 16 covers the top of the base 1, covering the groove, the tension spring 5 and part of the cross plate 6, to prevent fine debris of the coal sample from falling into the groove. The triangular prism-shaped part of the support part 2 is above the base 1 and is located in the center of the base 1, and is used to separate the three coal samples.

[0040] The three coal samples tested at one time are obtained from a batch of samples, so they have the same size. One clamping part 3 is stretched toward the outside of the base 1, the tension spring 5 is extended, the horizontal plate 6 moves outward, and the distance between the corresponding vertical rod 7 and the support part 2 becomes larger. A coal sample is placed in, and the vertical rod 7 and the support part 2 can clamp the coal sample. A small platform protruding upward is provided at one end of the horizontal plate 6 close to the vertical rod 7. The upper surface of the platform is flush with the upper surface of the bottom plate 16. The bottom surface of the coal sample can contact the bottom plate 16 and the platform to ensure that the coal sample is placed stably. In this way, the other two coal samples are placed.

[0041] Further optionally, the top end of the vertical rod 7 is open and recessed inward to form a second threaded hole, and the inner wall of the second threaded hole is provided with an internal thread; the edge positioning component 13 includes a circular overlap 14 at the top and an edge positioning nail below the overlap 14, the outer side surface of the edge positioning nail is provided with an external thread, and the edge positioning component 13 is concentrically arranged with the vertical rod 7; the top surface of the edge positioning component 13 is a plane and is provided with a sunken straight groove or a cross-shaped groove, which is convenient for a screwdriver to control the rotation of the edge positioning component 13;

[0042] After placing the coal sample, the edge positioning nail is screwed into the second threaded hole and threaded until the lower surface of the overlap 14 contacts the top surface of the coal sample, and the edge positioning nail is stopped from being screwed in, thereby positioning the height of the top surface of the coal sample.

[0043] Further optionally, the top end of the support portion 2 is open and recessed inward to form a third threaded hole, and the inner wall of the third threaded hole is provided with an internal thread; the middle positioning component 17 includes a circular overlap 15 at the top and a middle positioning pin below the overlap 15, and the outer side surface of the middle positioning pin is provided with an external thread, and the middle positioning component 17 is concentrically arranged with the support portion 2; the top surface of the middle positioning component 17 is a plane, and is provided with a sunken straight groove or a cross-shaped groove, which is convenient for a screwdriver to control the rotation of the middle positioning component 17;

[0044] After placing the three coal samples, the middle positioning nail is screwed into the third threaded hole and threaded until the lower surface of the overlap 15 contacts the top surfaces of the three coal samples. Then, the middle positioning nail is stopped from being screwed in, thereby positioning the height of the top surfaces of the three coal samples.

[0045] Optionally, the anti-collision frame 8 includes an upper support ring 18, a lower support ring 19 and three support rods 20, the upper support ring 18 and the lower support ring 19 are concentrically arranged, and the three support rods 20 are evenly arranged along the circumference of the upper support ring 18; the bottom of the support rod 20 is connected to the top surface of the side positioning component 13 of the corresponding vertical rod 7, the top of the support rod 20 is detachably connected to the upper support ring 18, and the lower part of the support rod 20 is detachably connected to the lower support ring 19;

[0046] The sensor 10 is arranged on the upper support ring 18. The vertical distance between the upper support ring 18 and the lower support ring 19 is fixed. By designing the installation position of the limit rod 9 on the side of the probe and the vertical distance between the upper and lower support rings 19, when the sensor 10 senses the limit rod 9, the distance between the bottom end of the probe and the top surface of the coal sample reaches the optimal observation distance (i.e. 10 mm).

[0047] Further optionally, the support rod 20 is divided into an upper part and a lower part at the position where it is connected to the lower support ring 19. The upper part is an inclined rod connected between the upper and lower support rings 19, and the lower part is a vertical rod connected between the side positioning component 13 and the lower support ring 19.

[0048] The bottom end of the lower portion of the support rod 20 is bonded to the top surface of the edge positioning component 13 , for example, by double-sided tape, to facilitate subsequent disassembly of the support rod 20 .

[0049] Further optionally, the upper portion of the support rod 20 is located outside the upper and lower support rings 19, and the support rod 20 is provided with an openable and closable clamping ring at the position facing the two support rings, so as to facilitate detachable connection with the corresponding support ring;

[0050] The upper portion of the support rod 20 is a telescopic sleeve structure, which is convenient for adjusting the length of the upper portion.

[0051] Further optionally, the diameter of the lower support ring 19 is equal to the diameter of the circle surrounded by the three vertical rods 7, and the diameter of the upper support ring 18 is larger than the lower support ring 19 and larger than the diameter of the bottom end of the probe;

[0052] Washers are bonded to the inner sides of the upper and lower support rings 19. The washers can be made of flexible rubber. Even if the sample stage moves too much and the edge of the probe hits the washer, the probe will not be damaged.

[0053] Further optionally, the lower support ring 19 is a circle formed by the intersection of two ends of a rod. By adjusting the length of the overlapping part of the two ends of the rod, the diameter of the lower support ring 19 can be adjusted to accommodate coal samples of different diameters.

[0054] When coal samples of different diameters are clamped between the clamping portion 3 and the support portion 2, the diameters of the circles formed by the three clamping portions 3 vary, necessitating lower support rings 19 of varying diameters. The lower support rings 19 of the present invention can be infinitely adjusted in diameter. To maintain the vertical height of the upper and lower support rings 19, when the diameter of the lower support ring 19 decreases, the upper portion of the support rod 20 lengthens and its inclination angle decreases; when the diameter of the lower support ring 19 increases, the upper portion of the support rod 20 shortens and its inclination angle increases. After the length of the upper portion of the support rod 20 is adjusted, a rubber ring tightly wrapped around the support rod 20 blocks the movable end of the outer sleeve, thereby temporarily fixing the relative position of the outer sleeve and the inner tube, and thus the length of the upper portion of the support rod 20. As the diameter of the lower support ring 19 changes, the support rod 20 also adjusts its connection position with the upper and lower support rings 19.

[0055] The support rod 20 can be made of iron, and the angle of the upper portion can be adjusted using pliers. The support rod 20 can also be of a fixed angle and length, and the appropriate support rod 20 is selected based on the diameter of the coal sample. Since the diameters of coal samples tested under the SEM are limited, several sets of support rods 20 are available. The upper and lower support rings 19 are made of metal or plastic.

[0056] Further optionally, the sensor 10 is installed on the upper support ring 18 through the support 21, and the support 21 is concave, and the support 21 is parallel to the tangent direction of the position where the support 21 is installed on the upper support ring 18; the groove in the middle of the support 21 has two opposite side surfaces and a bottom surface, and the sensor 10 is installed on one of the side surfaces. When the sensor 10 rises with the sample stage and approaches the limit rod 9, the limit rod 9 enters the groove of the support 21 and blocks the sensor 10. The sensor 10 senses the limit rod 9 and transmits the signal to the control mechanism that controls the movement of the original sample stage, pausing the upward movement of the original sample stage. At this time, the bottom end of the probe is 10 mm away from the top surface of the coal sample.

[0057] Because the overlapping edge 14 of the edge positioning member 13 can be positioned on the top surface of the coal sample, the relative positions of the bottom of the support rod 20 and the lower support ring 19 to the edge positioning member 13 are determined. Combined with the fixed vertical distance between the upper and lower support rings 19, this effectively transforms the problem of determining the spacing between the bottom of the probe and the top surface of the coal sample into a simple matter of how the sensor 10 senses the limit rod 9, a problem that is easily determined and controlled. The anti-collision frame 8 provides an additional layer of protection for the probe.

[0058] During use, place the sample stage described in the present invention on the original sample stage so that the support 21 of the sample stage corresponds to the side of the probe where the limit rod 9 is set, and move the sample stage to be directly below the probe so that the groove of the support 21 is directly below the limit rod 9. This can be done by observing with the naked eye. Then move the original sample stage and the sample stage upwards. According to the above method, when the sensor 10 senses the limit rod 9, it stops moving upwards. Then, the probe can be used to test various positions of the coal sample below by translating the sample stage. Reasonable design of the exposure of the anti-collision frame 8 can increase the range of the probe's translation. The probe can be translated to make the limit rod 9 disengage from the groove of the support 21, thereby increasing the flexibility of the probe's translation.

Claims

1. A sample stage for scanning electron microscope testing, characterized in that: The sample stage for SEM testing includes a base, a support portion, three movable clamping portions, and an anti-collision positioning assembly. A support column is provided in the center of the lower surface of the base. The support column can be inserted into the through hole of the original sample stage of the SEM, so that the base can be stably placed on the original sample stage. The base is equipped with three horizontally arranged tension springs that are evenly distributed in a radial pattern. The horizontal plate at the bottom of the clamping part is connected to the base through the tension springs, so that the clamping part can move back and forth along the radial direction of the base to expand or reduce the size of the bottom surface of the sample stage. The vertical rod and the supporting part of the clamping part are both vertical. The supporting part is detachably plugged into the center of the base. A coal sample can be placed between one vertical rod and the supporting part. The anti-collision positioning assembly includes an anti-collision frame and a limit rod. The bottom of the anti-collision frame is connected to the top of the three vertical rods. The sensor is installed on the anti-collision frame, and the limit rod is installed on the side of the probe. When the sensor senses the limit rod, the original sample stage stops moving up to prevent the coal sample from colliding with the probe. The clamping portion is L-shaped and includes a horizontal plate, a vertical rod and a side positioning component. One end of the horizontal plate is connected to the tension spring, and the other end is connected to the bottom of the vertical rod. A second threaded hole is provided in the vertical rod for connecting to the side positioning component. The anti-collision frame includes an upper support ring, a lower support ring and three support rods. The upper support ring is concentrically arranged with the lower support ring, and the three support rods are evenly arranged along the circumference of the upper support ring; the bottom of the support rod is connected to the top surface of the side positioning component of the corresponding vertical rod, the top of the support rod is detachably connected to the upper support ring, and the lower part of the support rod is detachably connected to the lower support ring; the sensor is arranged on the upper support ring.

2. The sample stage for scanning electron microscope testing according to claim 1, characterized in that: The base is circular, and three grooves are provided on the upper surface of the base, which are evenly distributed in a radial pattern. The grooves are recessed toward the base and are used to accommodate the transverse plate and the tension spring. A first threaded hole is provided in the center of the base for connecting the support portion. The top of the edge positioning component is provided with a flat and straight edge that extends outward and is used to support the top surface of the coal sample close to the vertical rod.

3. The sample stage for scanning electron microscope testing according to claim 2, characterized in that: An inner wall of the first threaded hole is provided with an internal thread, the first threaded hole is concentrically arranged with the base, and the top surface of the first threaded hole is flush with the upper surface of the base; The support part is a vertical rod, and a circular chassis is fixedly connected to the outer wall of the support part. The chassis has the same diameter as the base and is used to cover the upper surface of the base; the part of the support part below the chassis is cylindrical, and the outer wall of the part is provided with an external thread for connecting to the first threaded hole; the part of the support part above the chassis is triangular prism, and the three side faces are used to connect three coal samples respectively.

4. The sample stage for scanning electron microscope testing according to claim 2, characterized in that: The top end of the vertical rod is open and recessed inward to form a second threaded hole, the inner wall of the second threaded hole is provided with an internal thread; the edge positioning component includes a circular edge 1 at the top and an edge positioning pin below the edge 1, and the outer side of the edge positioning pin is provided with an external thread; After placing the coal sample, the edge positioning nail is screwed into the second threaded hole and threaded until the lower surface of the overlap contacts the top surface of the coal sample. The edge positioning nail is stopped from being screwed in, thereby positioning the height of the top surface of the coal sample.

5. The sample stage for scanning electron microscope testing according to claim 3, characterized in that: The top end of the support portion is open and recessed inwardly to form a third threaded hole, the inner wall of which is provided with an internal thread; the middle positioning component includes a circular lap side 2 at the top and a middle positioning pin below the lap side 2, and the outer side surface of the middle positioning pin is provided with an external thread; After placing the three coal samples, the middle positioning nail is screwed into the third threaded hole and threaded until the lower surface of the second overlap contacts the top surfaces of the three coal samples. Then, the middle positioning nail is stopped from being screwed in, thereby positioning the height of the top surfaces of the three coal samples.

6. The sample stage for scanning electron microscope testing according to claim 1, characterized in that: The support rod is divided into upper and lower parts at the position where it is connected to the lower support ring. The upper part is an inclined rod connected between the upper and lower support rings, and the lower part is a vertical rod connected between the side positioning component and the lower support ring. The bottom end of the lower part of the support rod is bonded to the top surface of the edge positioning component.

7. The sample stage for scanning electron microscope testing according to claim 6, characterized in that: The diameter of the lower support ring is equal to the diameter of the circle surrounded by the three vertical rods, and the diameter of the upper support ring is larger than that of the lower support ring; washers are bonded to the inner sides of the upper and lower support rings.

8. The sample stage for scanning electron microscope testing according to claim 7, characterized in that: The lower support ring is a circle formed by the intersection of the two ends of a rod. By adjusting the length of the overlapping part of the two ends of the rod, the diameter of the lower support ring can be adjusted to adapt to coal samples of different diameters.

9. The sample stage for scanning electron microscope testing according to claim 8, characterized in that: The sensor is installed on the upper support ring through a support. The support is concave in shape and parallel to the tangent direction of the position where the support is installed on the upper support ring. The groove in the middle of the support has two opposite side surfaces and a bottom surface, and the sensor is installed on one of the side surfaces. When the sensor rises with the sample stage and approaches the limit rod, the limit rod enters the groove of the support and blocks the front of the sensor. The sensor senses the limit rod and transmits a signal to the control mechanism that controls the movement of the original sample stage, thereby pausing the upward movement of the original sample stage.

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