CN111257359A

CN111257359A - Method for adjusting sample to align with axis of rotating shaft

Info

Publication number: CN111257359A
Application number: CN201811450212.4A
Authority: CN
Inventors: 王宏涛; 张奕志
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2020-06-09
Anticipated expiration: 2038-11-30
Also published as: CN111257359B

Abstract

The invention discloses an adjusting method for aligning a sample to the axis of a rotating shaft, which comprises the steps of manufacturing a sample clamping nozzle, inserting a sample rod with the sample into a transmission electron microscope and the like. When the rotating shaft rotates, the sample is adjusted to be aligned to the axis of the rotating shaft, so that the region to be observed of the sample is always in the observation field of the transmission electron microscope.

Description

Method for adjusting sample to align with axis of rotating shaft

Technical Field

The invention relates to a sample rod used under an electron microscope and a transmission electron microscope.

Background

Transmission Electron Microscopy (TEM) can see microscopic structures smaller than 0.2 μm, which are not visible under ordinary optical microscopy, and these structures are called submicrostructures or ultrastructures. In 1932 Ruska invented a transmission electron microscope using electron beam as light source, and the resolution of TEM can reach 0.2nm at present.

In situ observation techniques have a long history in transmission electron microscopy studies. By applying various physical actions on a sample and observing the change of the microstructure and the chemical state of the material by using a transmission electron microscope (transmission electron microscope), the performance expression of the material or a device in the actual use process can be intuitively researched, and the method has important practical significance for the research of the material performance. The difficulty of the in-situ technique in the transmission electron microscope lies in that not only the physical action needs to be accurately applied to the sample, but also a series of harsh conditions are required to be met, for example, the ultra-high vacuum degree of the electron microscope system needs to be maintained, the extremely high stability of the sample stage is ensured, the imaging light path cannot be interfered, and the whole structure needs to be compact so as to be suitable for a narrow sample chamber of the transmission electron microscope and the like. Therefore, the difficulty of the in-situ electron microscope technology is mainly reflected in the research and manufacture of the in-situ sample rod.

An article "Compact design of emission electron microscope-scanning tunneling microscope holder with a small-dimensional core motion", published 2003 by Svensson et al, sweden k, discloses a three-dimensional piezoelectric probe which is part of a sample rod of a transmission electron microscope, the piezoelectric probe comprising a piezoelectric ceramic tube and a small ball, the small ball being fixed to the end of the piezoelectric ceramic tube, the small ball being provided with a sample holder which holds the small ball by a flexible wire claw, the piezoelectric ceramic tube controlling the small ball to make a cyclic motion of a small amplitude of "slow movement and rapid withdrawal" (the axial direction of the piezoelectric ceramic tube is less than 2.5 micrometers, and the other two directions are less than 30 micrometers). The flexible wire claw grips the small ball through friction force, the piezoelectric ceramic tube makes circular motion, and the sample holder is thrown step by step through the friction force between the flexible wire claw and the small ball, so that displacement control (rough adjustment) with large stroke and large step length is generated. The displacement control (fine adjustment) which is smaller in stroke and continuously adjustable and is generated by the piezoelectric ceramic tube is combined, and the accurate displacement control of the large stroke (about 3 mm) with three degrees of freedom (one degree of freedom in axial translation and two degrees of freedom in rotation around a small ball) can be realized in a small space in an accumulated mode. The three-dimensional piezoelectric probe is applied to a NanoEx 3D STM/EP system and a NanoEx 3D lndentor system of the company FEl in the USA, and realizes in-situ STM, in-situ indentation and electrical probing under a transmission electron microscope.

The disadvantages of such three-dimensional probes are: 1. the flexible wire claws are easy to deform, the shape of the flexible wire claws needs to be adjusted frequently in order to keep the friction force between the flexible wire claws and the small ball, but the number of the flexible wire claws is multiple, and the consistency of each flexible wire claw cannot be ensured, so that the reliability and the precision of the three-dimensional probe are lower along with the use time and times. 2. The length of the flexible wire claw enables a gap to be reserved between the sample holder and the small ball, and when the small ball moves circularly, the sample holder is far away from the small ball or is close to the small ball along the wire claw, so that the axial displacement of the sample is realized, but the sample holder is hung on the small ball through the flexible wire claw, the sample holder and the sample on the sample holder can fall downwards under the action of gravity, and the position precision is not high. The observation visual field range in the transmission electron microscope is nano-sized and micron-sized, and the position deviation of the sample under the action of gravity is likely to cause that the region to be observed on the sample deviates from the observation visual field range of the electron microscope and cannot be observed; and the presence of positional deviation makes it difficult to adjust the region to be observed of the sample to a position and angle suitable for observation. 3. When the probe clamping device moves back and forth along the axial direction of the piezoelectric ceramic tube, the relationship between the shape of the flexible wire claw and the friction force is complex, and the adjustment of the shape of the flexible wire claw is difficult to ensure that the friction force is always appropriate. In addition, the probe clamping device is influenced by gravity, so that coupling motion is easy to generate during coarse adjustment, and the probe is difficult to accurately control; even because the shape of the flexible wire claw is not properly adjusted, the flexible wire claw cannot grab the small ball, and the probe clamping device can fall into the equipment to cause the damage of the equipment.

Disclosure of Invention

The invention aims to provide a multi-degree-of-freedom sample rod which has X/Y/Z three-direction translation and X-axis rotation driving capability and is stable in performance in repeated use.

The multi-freedom-degree sample rod is provided with a nanometer positioner, the nanometer positioner comprises a driving piece, a joint ball and a pressing piece assembly, the joint ball is fixed with the driving piece, the pressing piece assembly comprises at least two pressing pieces and an elastic connecting assembly, the elastic connecting assembly is connected with the adjacent pressing pieces, the joint ball is embraced by the pressing pieces, and pre-tightening force is formed between the pressing pieces and the joint ball. Such as a piezo ceramic tube as the driver.

Casting die

Preferably, each pressing piece is provided with a concave part and a connecting part respectively, the elastic connecting assembly is arranged between the connecting parts of the adjacent pressing pieces, and the concave parts of all the pressing pieces form a concave groove matched with the joint ball. The concave groove is in line contact with the joint ball or surface contact or point contact; the elastic connecting assembly enables a pretightening force to be formed between the pressing piece and the joint ball, and when the joint ball is static or the driving piece drives the joint ball to move slowly, the static friction force between the joint ball and the pressing piece enables the pressing piece to be static relative to the joint ball. When the driving piece drives the joint ball to reset quickly, sliding friction force is generated between the joint ball and the pressing piece, and when the joint ball resets, the pressing piece keeps in the original position and does not reset along with the joint ball, or the pressing piece moves along with the joint ball to reset, but the movement stroke is smaller than the reset stroke of the joint ball.

Preferably, the dimples are hemispherical, or V-shaped, or conical.

Preferably, the pressing member is a one-piece plate body, and the recessed portion is located in the center of the plate body.

Preferably, the first pressing member and the second pressing member are respectively located on both sides of the joint ball. Or the first pressing piece is arranged above the second pressing piece, and the concave groove of the second pressing piece is a through hole. The inner wall of the through hole is in a hemispherical shape, a V shape or a conical shape, etc. Preferably, the first pressing member is provided with a sample holder.

Preferably, the compression element is located on the outside of the ball. When the sample rod is vertically placed, the nanometer positioner faces upwards, and the two sides are the outer sides of the sample rod in the vertical placement, left, right, front and back. Preferably, the pressing member is provided with a sample holding portion. When all the pressing pieces are assembled in place, the sample holding parts are combined into a sample clamp, and the sample clamp is used for installing samples. During installation, the pressing piece is used for holding the joint ball from two sides of the joint ball, and the elastic connecting assembly provides pre-tightening force between the pressing piece and the joint ball.

Preferably, the pressing piece comprises a first pressing piece and a second pressing piece, a plurality of mounting positions are uniformly distributed around the recessed portion of the first pressing piece and the recessed portion of the second pressing piece respectively, each mounting position corresponds to one elastic connecting assembly, and the mounting position of the first pressing piece is aligned with the mounting position of the second pressing piece. Therefore, one end of the elastic connecting assembly is installed at the installation position of the first pressing piece, and the other end of the elastic connecting assembly is installed at the installation position of the second pressing piece.

Preferably, the first element has a wear resistant layer on the surface of the dimple. Preferably, the dimpled surface of the second element has a wear resistant layer.

Elastic connecting assembly

Preferably, the elastic connection assembly is a spring or an elastic column (such as a silica gel column, a rubber column, etc.) made of an elastic material, one end of the elastic connection assembly is fixed with the first pressing member, and the other end of the elastic connection assembly is fixed with the second pressing member. After the two pressing pieces hold the joint ball, the elastic connecting assembly is in a deformation state, and the restoring force of the elastic connecting assembly provides pre-tightening force between the two pressing pieces and the joint ball.

Or the elastic connecting assembly consists of a screw rod and a spring, the spring is sleeved on the screw rod, the spring is positioned between the screw rod and the first pressing piece, and the mounting position of the second pressing piece is a screw hole meshed with the screw rod. After the screw rod is meshed with the mounting position of the second pressing piece, the spring is in a compressed state, the spring pushes the first pressing piece to the second pressing piece, and the spring provides pre-tightening force between the first pressing piece and the joint ball and between the second pressing piece and the joint ball.

Preferably, the mounting position of the first pressing piece is a through hole, and the through hole is in clearance fit with the screw rod. No friction exists between the through hole and the screw rod, and the spring is favorable for pushing the first pressing piece.

Preferably, the screw rod extends out of the mounting hole of the second pressing piece, or a fixing part is arranged between the screw rod and the second pressing piece. For example, after the second pressing member is mounted in place, the screw and the second pressing member are welded or bonded, or the screw thread on the screw is broken. When the joint ball moves circularly to drive the first pressing piece and the second pressing piece to move, the first pressing piece and the second pressing piece swing to cause vibration between the screw rod and the second pressing piece, so that the screw rod is loosened and even separated from the second pressing piece; loosening of the screw will affect the precise control of the position; the screw rod breaks away from the second casting die, and then causes first casting die and sample to drop, damages the electron microscope.

The pretightening force between the pressing piece and the joint ball is adjusted by the screwing degree of the screw rod in a screw rod and spring mode, so that the design and manufacture requirements on elasticity are reduced.

Driving member

Preferably, the driving part is a piezoelectric ceramic tube, the piezoelectric ceramic tube is a hollow tube body, one end of the piezoelectric ceramic tube is fixed with the joint ball, and the other end of the piezoelectric ceramic tube is arranged on the sample rod; the piezoelectric ceramic tube is provided with an inner surface and an outer surface, a plurality of conductive area groups are arranged on one surface of the piezoelectric ceramic tube, each conductive area group comprises two symmetrical conductive areas, all the conductive areas are mutually independent, and each conductive area is provided with a conductive wire; the other surface of the piezoelectric ceramic tube is a whole area conductive part. The whole-area conductive part means that the conductive coating completely covers the other surface.

Preferably, the conductive area group is arranged on the outer surface of the piezoelectric ceramic tube, and the whole conductive area group is arranged on the inner surface of the piezoelectric ceramic tube. Or the conductive area group is arranged on the inner surface of the piezoelectric ceramic tube, and the whole conductive area group is arranged on the outer surface of the piezoelectric ceramic tube. If the conductive area groups are uniformly distributed along the outer (inner) surface of the piezoelectric ceramic tube, the whole area conductive part covers the inner (outer) surface.

Preferably, there is an insulating coating between adjacent conductive regions.

Preferably, the voltage direction of the two conductive regions of each conductive region group is opposite.

As preferred scheme, the joint ball passes through the ball seat and links to each other with piezoceramics pipe, and the ball seat includes the connecting rod fixed with the joint ball and the connecting seat fixed with piezoceramics pipe, and the diameter ratio of connecting rod is little than the diameter of joint ball.

As preferred scheme, connecting rod and connecting seat are detachable fastening connection. Such as a threaded connection, keyed connection, etc. During installation, the connecting rod penetrates through the groove through hole of the second pressing piece, the groove of the second pressing piece is in contact with the joint ball, and then the connecting rod is fixed with the connecting seat. Therefore, the second pressing piece is convenient to disassemble, assemble and replace.

Electrostatic discharge

Because the transmission electron microscope images with the electron beam, when the electron beam irradiates the sample, static electricity is accumulated on the region to be observed of the sample to generate an electrostatic field, and the electrostatic field deflects the electron beam to influence the imaging of the electron beam, so that the static electricity on the region to be observed of the sample needs to be led out.

As a preferable scheme: when the sample is a conductor or a semiconductor, a sleeve for loading the sample is arranged at the head end of the nano driver, a pre-tightening screw for locking the sample is arranged on the sleeve, the nano driver is provided with a static electricity leading-out piece, the pre-tightening screw and the static electricity leading-out piece can conduct electricity, an electric path for communicating the pre-tightening screw and the static electricity leading-out piece is arranged on the nano driver, the static electricity leading-out piece is connected with a lead, and the lead is grounded or connected to a constant voltage power supply provided by external equipment or to a rod body of the sample rod so as to be connected to a transmission electron. Therefore, static electricity on the to-be-observed area of the sample is transmitted to the pre-tightening screw through the sample, the pre-tightening screw reaches the static electricity leading-out piece through an electric path on the nano driver, and current on the static electricity leading-out piece is led out through the lead.

Preferably, the electric path can be a lead for connecting the pre-tightening screw and the static electricity lead-out piece, and the length of the lead is only required to be provided with redundancy, so that the lead does not influence the activity of the nano driver. Or, the nano-driver adopts the structure, the sleeve is arranged on the first pressing piece, the static electricity leading-out piece is fixedly arranged on the second pressing piece, the first pressing piece, the sleeve and the second pressing piece are all conductors, at least one elastic connecting assembly is arranged between the first pressing piece and the second pressing piece, each elastic connecting assembly comprises a screw rod and a spring, the screw rods and the springs are all conductors, and the surfaces of the through holes corresponding to the screw rods of the first pressing piece and the second pressing piece are kept conductive. Thus, the flow direction of the static electricity is: sample → preloaded screw → first presser → spring → screw → second presser → electrostatic conductive ejector.

Preferably, the static electricity leading-out part is a conductive screw, the second pressing part is provided with a screw hole matched with the conductive screw, the nut of the conductive screw faces away from the first pressing part, and the lead is positioned between the nut of the conductive screw and the second pressing part. This is because this allows for the installation of a conductive screw, securing the wire to the conductive screw. Or the lead is welded with the conductive screw and directly welded on the conductive screw, so that the lead is more stably connected.

Preferably, the screw portion of the conductive screw is located within the second presser member. That is, the conductive screw is located in the second pressing member except for the head portion, and the tail portion thereof does not extend out of the second pressing member and is further screwed into the first pressing member. Therefore, the stability of the conductive screw is prevented from being influenced by the relative motion among the first pressing piece, the joint ball and the second pressing piece.

Preferably, the head of the conductive screw is exposed out of the second pressing member. Thus, the wire can be pressed between the conductive screw and the surface of the second pressing member, the wire is not embedded in the screw hole of the second pressing member, and the wire is not easy to break.

Preferably, the tail part of the conductive screw is fixed with the second pressing piece in a spot welding mode. The conductive screw is fixed in the second pressing piece through spot welding, so that the stability of current transmission is kept, and the conductive screw is prevented from being separated from the second pressing piece and falling off. The transmission electron microscope is very expensive and difficult to maintain, once a part or a sample and the like fall off in a sample cavity of the transmission electron microscope, huge loss is caused, the space of the sample cavity is limited, and the falling part is difficult to take out, so that the connection reliability of each part of the sample rod is very important.

Sample clamping nozzle

The sample needs to be loaded on the sample rod. For example, the sample is a bar with a diameter of 0.3mm and a length of 10 mm. And the region to be observed of the sample is a region with a thickness of 100nm or less at one end of the sample, such as a needle tip or attached nanoparticles. There may be multiple regions to be observed on each sample. When a sample observation experiment is carried out, the sample rotates around the shaft, and in order to keep the region to be observed of the sample in the observation field of the transmission electron microscope all the time, the region to be observed of the sample is required to be close to the rotating shaft as much as possible. The typical way to mount the sample is: the sleeve is arranged at the front end of the sample rod, the locking screw presses the sample on the wall of the sleeve from one side, and in order to enable the sample to be smoothly and nondestructively installed in the sleeve, the inner diameter of the sleeve needs to be thicker than that of the sample, so that the area to be observed of the sample can deviate from the central axis of the sample rod. However, the observation scale of the transmission electron microscope is usually micron-scale or nanometer-scale, and when the region to be observed of the sample is observed, it is likely that the region to be observed of the sample after the sample is rotated by the piezoelectric rubbing mechanism exceeds the observation field of the transmission electron microscope. In order to be able to observe samples of various sizes, a sample clamping nozzle is provided for mounting the sample, and the sample clamping nozzle are arranged as a sample assembly at the front end of the sample rod.

Preferably, the sample holder includes a grip portion and a connection portion, and the sample is loaded on the grip portion. When the sample is clamped, the sample is partially inserted into the copper pipe, and then one end of the inserted copper pipe is clamped by a tool (such as a pliers) so that the inner surface of the section of copper pipe is attached to the sample to form an arch, wherein the arch is a clamping part, so that the sample is limited at the arch, and the assembly of the sample and the sample clamping nozzle is completed. The connecting portion of sample holder mouth and sleeve pipe clearance fit, for example, the sleeve pipe is circular, then the connecting portion of sample holder mouth is cylindrical, as long as connecting portion can with sleeve pipe clearance fit can. Therefore, the pre-tightening screw directly abuts against the sample clamping mouth, samples of any size can be installed on the sample clamping mouth, and then the sample assembly is installed on the sample rod, so that the universality of samples which can be loaded on the sample rod is good. The pre-tightening screw only needs to abut against the sample clamping mouth tightly, the pre-tightening screw does not contact with a sample, the sample is not damaged, and the installation gap between the sample clamping mouth and the sample rod can be set to be as small as possible, so that the sample is ensured to be as close as possible to the sample rod shaft.

Preferably, the clamping portion has a loading hole at a linear position. The sample loading hole is arranged at the center line position of the clamping part, so that the sample can be clamped in a balanced manner.

Preferably, buffering gaps communicated with the sample loading holes are symmetrically formed in two sides of the sample loading holes. When the size of the sample loading hole is smaller than that of the sample, the buffer gap can enable the sample loading hole to have a space with increased size, so that the sample can be smoothly loaded into the sample loading hole.

Preferably, the clamping portion gradually shrinks from the bottom to the top, the top is flat, and the clamping portion is hollow. The flat top reduces the occupied space of the sample clamping mouth, and the sample is convenient to operate. The hollow clamping part increases the depth length of the sample.

Preferably, the clamping portion and the connecting portion are fixedly connected or integrally formed, the clamping portion is located above the connecting portion. The fixed connection can be by welding. The clamping part and the connecting part can be smoothly connected in an integrated forming mode.

Preferably, the connecting part is a solid column or the connecting part is hollow. The solid column is not easy to be extruded and deformed, and the pre-tightening screw props against the solid column to keep the reliability of the installation of the sample-sample clamping nozzle. When the connecting part is hollow, the extending length of the sample is further increased, and the manufacturing cost of the clamping nozzle is reduced.

Preferably, the connecting portion has a recess. The pretension screw is correspondingly inserted into the pit of the connecting part, so that the connecting part can be locked, and the sample can be prevented from rotating and moving.

Preferably, the sample holder mouth is a conductor. Thereby facilitating the outward conduction of static electricity accumulated on the region to be observed of the sample.

Preferably, the sample holder nozzle may be a thin-walled copper tube. The thin-wall copper pipe is used, so that the cost is low, and the sample can be adapted to samples with different diameters.

When the sample rod has a clamping mouth, the electrostatic flow direction is as follows: sample → clamp mouth → preloaded screw → first presser → spring → screw → second presser → static conductive ejector.

Method for adjusting sample to align with axis of rotating shaft

In order that the region to be observed of the sample is always within the observation field of the transmission electron microscope when the rotating shaft rotates, it is necessary to make the region to be observed of the sample as close as possible to the rotation axis of the rotating shaft.

Method for adjusting a region of a sample to be observed onto the axis of rotation of a spindle, comprising the steps of:

s1, manufacturing the sample clamping mouth, clamping a sample in the sample clamping mouth, and then installing the sample clamping mouth into a sample rod clamp;

s2, inserting the sample rod with the sample into the transmission electron microscope, finding a region to be observed of the sample, and selecting a characteristic point of the region to be observed of the sample according to the principle that the characteristic point is easy to distinguish in the rotation process;

s3, rotating the rotating shaft to 0 degree, and recording the position of the sample characteristic point projected on the electron microscope screen as D1; rotating the rotating shaft to 180 degrees, and recording the position of the sample characteristic point projected on the screen of the electron microscope as D2;

s4, driving the nanometer positioner, driving along the Y direction, and moving the position of the sample characteristic point projected on the electron microscope screen to the central position Dz of D1 and D2;

s5, enabling the rotating shaft to rotate to 90 degrees, driving the nanometer positioner, and driving the position, which projects the characteristic point of the sample on the screen of the electron microscope, to move to Dz along the Z direction;

s6, enabling the rotating shaft to rotate to 0 degree, driving the nanometer positioner, and driving the position where the sample characteristic point is projected on the electron microscope screen to move to Dz along the Y direction;

s7, repeating S5-S6 until the position of the sample feature point projected on the screen of the electron microscope is unchanged in the transverse position under the electron microscope when the sample feature point rotates back and forth;

and S8, increasing the magnification of the transmission electron microscope, and repeating S3-S7. Until the random movement caused by mechanical error is not negligible, the characteristic point of the sample is accurately positioned on the rotating shaft.

The sample characteristic points are projected to the position on the screen of the electron microscope to move to the same X position along the X direction.

The whole diameter of the transmission electron microscope sample rod is about 15mm, an O-ring groove for sealing needs to be installed, enough structural rigidity is reserved, and the space diameter of the rotating shaft does not exceed 10 mm.

Self-positioning of sample rod axis

In order to realize the rotation of the sample around the shaft by 360 degrees, the sample rod is arranged to comprise a shell and a rotating shaft, the shell is coaxial with the rotating shaft, and the rotating shaft is positioned in an inner cavity of the shell; the inner cavity is internally provided with a piezoelectric twisting mechanism for twisting the rotation of the rotating shaft and a self-positioning mechanism, the self-positioning mechanism is provided with symmetrical inclined planes, and the inclined planes are in contact with the rotating shaft. No matter how the rotating shaft rotates, the central shaft of the rotating shaft can always automatically reset to the original position under the action of the inclined surface, so that the phenomenon that the area to be observed of the sample is separated from the observation visual field of the transmission electron microscope due to the displacement of the center of the rotating shaft is avoided. Preferably, the rotating shaft is a ceramic shaft.

Preferably, the self-positioning mechanism comprises a support block, the support block is provided with symmetrical inclined planes, and the inclined planes of the support block are in contact with the rotating shaft. Preferably, the inclined plane of the supporting block is provided with a wear-resistant layer, and the wear-resistant layer is a contact part with the rotating shaft. Preferably, a plurality of support blocks are distributed along the axial direction of the rotating shaft.

Preferably, the self-positioning mechanism comprises a pressure plate, the pressure plate is provided with a flat plate, and the two sides of the flat plate are symmetrically provided with a slope. The rotating shaft is limited between the supporting block and the pressing plate, so that the rotating shaft does not displace up and down and left and right when rotating around the shaft. Preferably, each support block corresponds to a press plate, the support block is arranged at the lower part, and the press plate is arranged at the upper part. Alternatively, the self-positioning mechanism includes a plurality of pallets and a platen.

Preferably, the pressing plate is provided with a pair of mounting wings, and the mounting wings are provided with fixing holes; the mounting wing is located at one end of the slope. The inner side of the flat plate is provided with a wear-resistant layer which is the contact part with the rotating shaft.

Preferably, a framework is arranged between the shell and the rotating shaft, and the mounting wings are assembled on the framework through elastic mounting components. The elastic mounting component consists of a screw rod and a spring, the spring is sleeved on the rod body of the screw rod, and the spring is positioned between the mounting wing and a nut of the screw rod. The elastic mounting assembly enables the pressing plate to slightly move along the radial direction of the rotating shaft, so that the rotating shaft has pre-tightening force and can rotate. The rotating shaft is limited between the pressing plate and the supporting block, and the pre-tightening force is adjusted by rotating the screw rod during assembly. After the assembly is completed, the spring does not deform continuously when in use.

Rotating shaft driving assembly

Preferably, at least one group of rotating shaft driving assemblies is arranged between the framework and the rotating shaft, each group of rotating shaft driving assemblies comprises a driving unit, each driving unit comprises a substrate and a piezoelectric ceramic piece, and the substrate is an insulator or a PCB (printed Circuit Board).

One solution for driving the rotating shaft to move axially: the rotating shaft driving assembly comprises an axial driving unit, the shearing deformation direction of a piezoelectric ceramic piece of the axial driving unit is consistent with the axial direction of the rotating shaft, the piezoelectric ceramic piece is bonded on the substrate, and conductive coatings are coated on the surfaces of two sides of the piezoelectric ceramic piece. When the conductive coating is driven, a voltage signal is input between the conductive coatings, such as continuous or discontinuous sawtooth waves.

One proposal of driving the rotating shaft to rotate: the rotating shaft driving assembly comprises an autorotation driving unit, the shearing deformation direction of a piezoelectric ceramic piece of the autorotation driving unit is consistent with the annular direction of the rotating shaft, the piezoelectric ceramic piece is bonded on the substrate, and conductive coatings are coated on the surfaces of the two sides of the piezoelectric ceramic piece. When the conductive coating is driven, a voltage signal is input between the conductive coatings, such as continuous or discontinuous sawtooth waves.

One scheme of the combination of rotation and axial movement of the rotating shaft is as follows: the driving unit of the rotating shaft driving component comprises a substrate, a first piezoelectric ceramic piece and a second piezoelectric ceramic piece; the deformation direction of the first piezoelectric ceramic piece is orthogonal to that of the second piezoelectric ceramic piece, and conductive coatings are coated on the surfaces of the two sides of the first piezoelectric ceramic piece and the second piezoelectric ceramic piece. When the conductive coating is driven, a voltage signal is input between the conductive coatings, such as a continuous sawtooth wave.

The deformation direction of the first piezoelectric ceramic piece is orthogonal to the deformation direction of the second piezoelectric ceramic piece, for example, the deformation direction of the first piezoelectric ceramic piece is along the axial direction (the front-back direction) of the rotating shaft and is used for driving the rotating shaft to translate back and forth, and the deformation direction of the second piezoelectric ceramic piece is along the circumferential direction (the rotating direction) of the rotating shaft and is used for twisting the rotating shaft to rotate.

Preferably, the first piezoelectric ceramic sheet is stacked on the second piezoelectric ceramic sheet, or the second piezoelectric ceramic sheet is stacked on the first piezoelectric ceramic sheet; the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are fixedly bonded. Preferably, the drive unit is provided with a wear layer. The wearing layer directly contacts with the rotating shaft, so that the abrasion is reduced, and the service life of the driving unit is prolonged.

Preferably, one side surface of the first piezoelectric ceramic piece is conducted with one side surface of the second piezoelectric ceramic piece, and the first piezoelectric ceramic piece and the second piezoelectric ceramic piece share one lead.

Preferably, the rotating shaft driving assemblies are arranged in three groups or five groups along the axial direction of the rotating shaft. Preferably, five groups of rotating shaft driving assemblies are arranged, two groups of rotating shaft driving assemblies are symmetrically arranged at the front and the rear of the rotating shaft respectively, and a group of rotating shaft driving assemblies is arranged in the middle. The two sets of rotating shaft driving assemblies limit the force of rotating shaft rotation and axial movement, and the plurality of sets of rotating shaft driving assemblies apply the force in the same direction to the rotating shaft, so that the rotating shaft rotation and the axial movement are facilitated.

Framework

The skeleton is arranged between the shell and the rotating shaft, and the skeleton is coaxial with the shell and the rotating shaft. The framework is used as a transition part between the rotating shaft and the shell, when the rotating shaft and the framework are assembled, the rotating shaft and the framework are coaxial, and then the rotating shaft and the framework are installed in the shell, so that the rotating shaft, the framework and the shell are coaxial, and the installation precision is improved. In addition, the framework also provides a mounting position for the rotating shaft driving assembly, and the framework also plays a role in separating the rotating shaft from the lead and avoiding the lead from interfering the movement of the rotating shaft.

As preferred scheme, the skeleton has the matching portion with the inner wall clearance fit of shell, holds the holding tank of pivot and the installation department that is used for bearing the accessory, and the holding tank has the inclined plane of symmetry, is fixed with printed circuit board on the installation department, has connecting wire on the printed circuit board.

Preferably, the support block is fixed in the accommodating groove, and the accommodating groove is provided with a plurality of sections along the axial direction of the framework; be equipped with the installation cavity that holds pivot drive assembly on the skeleton, holding tank and installation cavity interval distribution. After the rotating shaft driving assembly is installed in place, the wear-resistant layer of the rotating shaft driving assembly forms an inclined plane for limiting the rotating shaft.

Preferably, each driving unit is provided with a connecting circuit board for current circulation, the connecting circuit board is a PCB printed circuit board, and a circuit electrically communicated with the rotating driving assembly is arranged on the connecting circuit board; each rotating shaft driving assembly corresponds to one switching circuit board, the switching circuit board is a PCB printed circuit board, and a communicating circuit is arranged on the switching circuit board; the current of the connecting circuit board is collected in the switching circuit board, the switching circuit board is connected with the conveying lead, and the conveying lead is connected with the signal connector on the sample rod. The signal connector is connected with an external signal source, and the driving unit outputs a control signal. The mode of adopting the circuit board realizes the signal of telecommunication transmission, avoids the wire to disturb the pivot and rotates.

Preferably, the switching circuit board is fixed with the framework, and the rotating shaft is located below the switching circuit board. Preferably, the adapter circuit board is located between the pressing plate and the rotating shaft driving assembly. The adapter circuit board is a PCB printed circuit board, the weldable area of the driving unit is limited, the welding is not firm, and the adapter circuit board can reduce the touch on the conducting wire on the driving unit in the assembling process so as to protect the welding point.

Preferably, the connecting circuit board and the adapting circuit board are electrically connected by a lead.

Preferably, the framework is cylindrical, a groove is cut in one side of the framework and penetrates through the framework in the axial direction, and the accommodating groove and the mounting cavity are both positioned on the groove; the arc surface of the framework is used as the bottom, the opening of the groove is used as the top, a gap is arranged at the position for placing the connecting circuit board, and part of the framework wall is cut off from the top to the bottom by the gap. The walls at the two ends of the notch play a role in positioning the connecting circuit board.

Preferably, the width of each connecting circuit board is smaller than or equal to the wall thickness of the framework, and the connecting circuit boards are fixed on the top surfaces of the notches by screws.

Preferably, the framework wall plane for mounting the adapter circuit board is higher than the framework wall plane for mounting the connecting circuit board. Therefore, the switching circuit board is partially suspended and is installed in a staggered mode with the connecting circuit board below the switching circuit board, and installation space is saved; moreover, a gap is reserved between the switching circuit board and the connecting circuit board, and the short circuit of the wires is avoided.

Preferably, the framework is provided with a mounting threaded hole, and the threaded hole penetrates through the framework from top to bottom. The threaded holes are through holes, so that the framework is convenient to clean, the sample rod is kept clean, and the sample cavity in the transmission electron microscope is prevented from being polluted and interfered.

Optical fiber access

An optical fiber is connected into the sample rod, and the optical fiber has the following functions: 1) adjusting a light source outside the device to be light with a specific spectrum, introducing an electron microscope, irradiating a sample, and applying an electromagnetic field; 2) light emitted/reflected by the sample during the experiment was collected, transmitted out of the electron microscope, measured and analyzed as follows: the temperature was measured by measuring the black body radiation emitted by the sample.

Preferably, the optical fiber groove is formed in the side face of the framework, and the optical fiber groove axially penetrates through the framework. And the side surface of the framework is provided with an optical fiber groove for the optical fiber to pass through, so that the optical fiber can be prevented from being abraded.

As the preferred scheme, the head of the sample rod is provided with a front-end circuit board which is a PCB (printed Circuit Board), the front-end circuit board is connected with the optical fiber groove, and the front-end circuit board and the optical fiber groove are positioned on the same straight line. The optical fiber groove is formed in the side face of the framework, the front end circuit board is arranged at the head of the sample rod, the optical fiber groove is connected with the front end circuit board, the front end circuit board has the function of guiding the optical fiber, the head of the optical fiber passes through the front end circuit board, the head of the optical fiber has smaller bending amplitude, and if the bending amplitude of the head of the optical fiber is too large, the optical signal attenuation is caused, and even the optical fiber is broken. The optical signal is attenuated, the signal-to-noise ratio of the signal is reduced, or the signal cannot be measured below the measurement range of the instrument.

Preferably, the front-end circuit board is mounted to the frame via a mounting block. Preferably, the mounting block fixes the front-end circuit board to the frame by means of a bolt. The front-end circuit board has a guide plane for guiding the optical fiber, the guide plane being flush with the optical fiber groove. The guide plane extends towards the direction of the sample clamping mouth, and the optical fiber is close to the sample along the guide plane.

Preferably, the framework is symmetrically provided with two optical fibers. Correspondingly, the front-end circuit board is provided with symmetrically arranged guide planes which are connected with the optical fiber grooves one by one. Two optical fiber grooves are formed, optical fibers can pass through any one optical fiber groove, or two optical fibers are used and respectively pass through the two optical fiber grooves, for example, different spectrums are passed, or one optical fiber emits light, and the other collects light.

Preferably, the fiber groove is in the same line with the connection circuit board. The connecting circuit board is arranged along the path where the optical fiber groove is located, the lead-out wire of the connecting circuit board can be led out from the inner wall of the framework and can also pass through the optical fiber groove, and therefore the arrangement of the lead and the rotation of the rotating shaft are not interfered with each other.

Preferably, the fiber groove is linear and can accommodate at least 0.5mm diameter optical fiber.

Electric wire leading-out

The lead of the front end circuit board needs to be connected with an external control box and passes through the framework from the outside, long-term contact friction not only causes abrasion to the lead, but also the lead has small diameter, various leads are complicated and are easy to be wound mutually. The bottom of the framework is provided with a wire passing groove for a lead to pass through, so that the lead can be prevented from being worn and wound.

As the preferred scheme, the bottom of the framework is provided with a wire passing groove which axially penetrates through the framework and is a groove with an opening towards the bottom.

Preferably, the lead of the front end circuit board passes through the wire passing groove.

Arrangement of piezoelectric ceramic plates and electrodes

The piezoelectric ceramic piece for driving the rotating shaft to translate or rotate is a piezoelectric ceramic shear slice which can generate shear deformation under the action of an external electric field along the thickness direction.

Preferably, the surfaces of the two sides of the piezoelectric ceramic plate are uniformly coated with conductive coatings which are an upper electrode and a lower electrode.

Preferably, the driving unit comprises a substrate, a piezoelectric ceramic piece and a wear-resistant sheet, the substrate is provided with a ceramic piece area and an electrode area, the piezoelectric ceramic piece is stacked and bonded on the ceramic piece area, the electrode area is provided with a plurality of circuits, and the plurality of circuits are electrically connected with the conductive coating on the surface of the piezoelectric ceramic piece.

Preferably, the ceramic plate area has one piezoelectric ceramic plate, or at least two piezoelectric ceramic plates are stacked.

Preferably, when there are at least two piezoelectric ceramic sheets, the expansion and contraction directions of the piezoelectric ceramic sheets are different from each other.

Preferably, the substrate is a PCB.

Preferably, the substrate is a metal-based PCB printed circuit board.

Preferably, the substrate is an aluminum-based PCB printed circuit board. Preferably, the substrate is provided with a concave platform and a pair of mounting holes, the mounting holes are used as the front end and the rear end of the substrate, the ceramic chip area and the electrode area are positioned in the center of the substrate, and the concave platform is positioned at the front end and the rear end of the substrate and around the mounting holes; the ceramic wafer area and the electrode area are located on the left side and the right side of the substrate.

Preferably, the lower electrode of the lowest piezoelectric ceramic plate is directly contacted with the ceramic plate area on the substrate and is connected to the electrode area on the substrate through a circuit on the ceramic plate area; the surface of an upper electrode of the uppermost piezoelectric ceramic piece is provided with an area A and an area B; the area A is stuck with a wear-resistant sheet; the area B is electrically connected with a transfer lead; the other end of the transfer lead is electrically connected with the electrode area on the substrate.

Preferably, the switching lead is soldered in the area B; or the transfer lead is adhered to the B area by conductive glue.

Preferably, when there are a plurality of piezoelectric ceramic sheets, the upper electrode of each piezoelectric ceramic sheet has an overlapping area and an exposed area, except for the uppermost piezoelectric ceramic sheet; the overlapping area is electrically connected with the lower electrode of the upper layer of the piezoelectric ceramic sheet of the laminated piezoelectric ceramic sheet; the exposed area is electrically connected with a switching lead; the other end of the transfer lead is electrically connected with the electrode area on the substrate.

Preferably, the switching lead is soldered in the exposed area; or the transfer lead is adhered to the exposed area by conductive glue.

Preferably, the via leads are soldered to the electrode regions on the substrate.

Preferably, the overlapping region is in direct contact with the lower electrode of the piezoelectric ceramic sheet of the upper layer of the laminated piezoelectric ceramic sheet.

Preferably, the lower electrode is grounded. Because the upper electrode and the lower electrode of each piezoelectric ceramic piece can be equivalent to a capacitive load, and the voltage required for driving each piezoelectric ceramic piece is higher, when the lowest piezoelectric ceramic piece is driven by a high-frequency signal, the voltage signal is easy to leak to the framework, and an electron microscope can be damaged. Therefore, the lower electrode of the lowest piezoelectric ceramic plate is grounded, and the voltage leaked to the framework can be reduced.

Or, in another arrangement mode of the piezoelectric ceramic plate and the electrode, the driving unit comprises an electrode plate and the piezoelectric ceramic plate, and the piezoelectric ceramic plate is adhered and fixed on the surface of the electrode plate. The electrode plate is a conductor and is electrically connected with the lead-out wire.

As a preferred scheme, the driving unit comprises a first electrode plate, a first piezoelectric ceramic piece and a second electrode plate, wherein the first piezoelectric ceramic piece is subjected to shear deformation along the axial direction of the rotating shaft, or the first piezoelectric ceramic piece is subjected to shear deformation along the circumferential direction of the rotating shaft; the first piezoelectric ceramic plate is arranged between the first electrode plate and the second electrode plate, and the first electrode plate and the second electrode plate are respectively provided with respective lead terminals.

Preferably, the driving unit comprises a first electrode plate, a first piezoelectric ceramic piece, a second electrode plate, a second piezoelectric ceramic piece and a third electrode plate; the mounting sequence is a first electrode plate, a first piezoelectric ceramic piece, a second electrode plate, a second piezoelectric ceramic piece and a third electrode plate in turn; the shearing deformation direction of the first piezoelectric ceramic piece is different from that of the second piezoelectric ceramic piece; the third electrode plate is close to the rotating shaft but not in contact with the rotating shaft.

Preferably, the first electrode plate is bonded and fixed on the insulating layer, the insulating layer is bonded and fixed on the framework or the shell, and the third electrode plate is provided with a wear-resistant layer contacted with the rotating shaft. The first, second and third are for illustration purposes only, three electrode plates; the first and second are for illustration purposes only, with two piezoceramic wafers.

Preferably, the first electrode plate is grounded. Because the first electrode plate, the insulating layer and the framework can be equivalent to a capacitive load in a circuit, and the voltage required for driving each piezoelectric ceramic piece is higher, when each piezoelectric ceramic piece is driven by a high-frequency signal, the voltage signal is easy to leak to the framework, and an electron microscope can be damaged. Therefore, the first electrode plate is kept grounded, and the voltage leaked to the framework can be reduced. And the second electrode plate and the third electrode plate are driven by proper voltage signals, so that a required electric field can be obtained, and the realization of a driving function is not influenced.

Position information of the rotating shaft

The tail end of the rotating shaft is provided with a magnet, the framework is provided with a lead-out circuit board, the magnetic field changes along with the rotation and the back-and-forth movement, the magnetic field sensor measures the magnetic field, and the position information of the rotating shaft can be obtained through solving. The rotation angle of the rotating shaft is measured for processing data after experiments, and a projection angle is needed for three-dimensional reconstruction. The moving distance of the rotating shaft is measured so as to: 1) during the experiment, the rotation and the front-back coupling are reduced, and distance change information is needed; 2) during the experiment, the sample is positioned at the position when the sensor is calibrated, so that the error of the angle measurement is smaller. At present, the sample rod is mostly driven by three degrees of freedom, and the sample rod is driven by four degrees of freedom, so that the axial movement of the rotating shaft is increased, and distance change data are provided for later-stage experiments by measuring the moving distance of the rotating shaft.

The end of the rotating shaft is provided with a magnet, the framework is provided with a lead-out circuit board, the framework is provided with a notch, the lead-out circuit board comprises a bent part, the bent part is located in the notch, and the magnetic field sensor is fixed on the bent part. The magnetic field sensor is placed in the gap, so that the occupied space is reduced, and the diameter of the shell of the sleeved framework is reduced. The space of the gap is far larger than the space required for accommodating the magnetic field sensor, and enough operation space is provided for disassembling and maintaining the magnetic field sensor.

Preferably, the lead-out circuit board comprises a plane part, the plane part and a bent part are bent and covered on the framework, the plane part and the bent part are connected through a lead, and the magnetic field sensor is connected with the bent part through soldering tin. The lead-out circuit board is a PCB printed circuit board. The magnetic field sensor and the lead-out circuit board are connected through tin soldering, so that the magnetic field sensor can be fixed, one pair of pins on the lead-out circuit board can be short-circuited, and the number of wires to be connected is reduced.

Preferably, the flat portion and the bent portion are L-shaped, and the magnetic field sensor faces the magnet. The bent circuit board is used, so that the occupied area is small, and the circuit board is easy to disassemble. If the circuit board is not bent, the space is not enough for placing screws, and the circuit board needs to be fixed by gluing and is difficult to disassemble and maintain.

Preferably, the lead-out circuit board has two sets of lead-out terminals, one set of lead-out terminals is electrically connected with the lead of the driving unit, and the other set of lead-out terminals is electrically connected with the sample rod.

Method for carrying out in-situ dynamic three-dimensional reconstruction on sample by using multi-degree-of-freedom sample rod

The method for in-situ dynamic three-dimensional reconstruction of a sample by using the multi-degree-of-freedom sample rod comprises the following steps:

s1, manufacturing the sample rod, loading a sample into the head end of the sample rod, and inserting the sample rod into a transmission electron microscope;

s2, adjusting a characteristic point on the area to be observed of the sample to be aligned with the axis of the sample rod;

s3, rotating the rotating shaft by 180 degrees in an accumulated mode, and taking pictures at intervals of 1 degree;

and S4, importing the picture obtained in the step S3 into a computer for three-dimensional reconstruction.

The invention has the advantages that:

1. the pretension screw, the electric path and the static leading-out piece are arranged on the nanometer positioner, static electricity on the area to be observed of the sample is transmitted to the pretension screw through the sample, the pretension screw reaches the static leading-out piece through the electric path on the nanometer driver, and current on the static leading-out piece is led out outwards through the conducting wire, so that the influence on electron beam imaging caused by the generation of an electrostatic field on the area to be observed of the sample when an electron beam irradiates the sample is avoided.

2. Because the observation scale of the transmission electron microscope is usually micron-level and nanometer-level, when observing the region to be observed, it is likely that the region to be observed of the sample after the nanometer driver rotates the sample exceeds the observation field of the transmission electron microscope, in order to observe samples of various sizes, the sample clamping nozzle is arranged for installing the sample, and the sample clamping nozzle are arranged at the front end of the sample rod as sample components.

3. In order to realize the rotation of the sample around the shaft by 360 degrees, the sample rod is arranged to comprise a shell and a rotating shaft, the shell is coaxial with the rotating shaft, and the rotating shaft is positioned in an inner cavity of the shell; the inner cavity is provided with a piezoelectric twisting mechanism for twisting the rotation of the rotating shaft and a self-positioning mechanism, the self-positioning mechanism is provided with symmetrical inclined planes, and the inclined planes are in contact with the rotating shaft. No matter how the rotating shaft rotates, the central shaft of the rotating shaft can always automatically reset to the original position under the action of the inclined surface, so that the phenomenon that the area to be observed of the sample is separated from the observation visual field of the transmission electron microscope due to the displacement of the center of the rotating shaft is avoided.

4. The sample rod is provided with a framework, the framework is arranged between the shell and the rotating shaft, and the framework is coaxial with the shell and the rotating shaft. The framework is used as a transition part between the rotating shaft and the shell, when the rotating shaft and the framework are assembled, the rotating shaft and the framework are coaxial, and then the rotating shaft and the framework are arranged in the shell, so that the rotating shaft, the framework and the shell are coaxial, and the installation precision is improved; in addition, the framework also provides a mounting position for the rotating shaft driving assembly, and the framework also plays a role in separating the rotating shaft from the lead and avoiding the lead from interfering the movement of the rotating shaft.

5. The method comprises the following steps of (1) connecting an optical fiber into a sample rod, wherein the optical fiber has the functions of adjusting a light source outside the device into light with a specific spectrum, introducing an electron microscope, irradiating a sample and applying an electromagnetic field; secondly, collecting light emitted/reflected by the sample in the experiment, transmitting the light out of an electron microscope, and carrying out measurement and analysis, such as: measuring the blackbody radiation emitted by the sample to measure the temperature; the optical fiber groove for the optical fiber to pass through is formed in the side face of the framework, the front-end circuit board is connected with the optical fiber groove, the optical fiber head is led out by the front-end circuit board while the abrasion of the optical fiber is avoided, and the optical fiber head has smaller bending amplitude.

6. The sample rod is equipped with pivot drive assembly, and pivot drive assembly can make pivot axial displacement and rotation, satisfies the diversified observation of sample.

7. The sample rod can detect the position information of the rotating shaft, the magnetic field changes along with the rotation and the back-and-forth movement of the rotating shaft, the magnetic field sensor can detect the magnetic field, the position information of the rotating shaft can be obtained through solving, the magnetic field sensor is connected with the lead-out circuit board in a soldering mode, the magnetic field sensor can be fixed, one pair of pins on the lead-out circuit board can be in short circuit, and the number of wires needing to be connected is reduced; the leading-out circuit board comprises a plane part and a bent part, the plane part and the bent part are vertically laid on the surface of the framework, the magnetic field sensor is fixed on the bent part, and the bent circuit board is small in occupied area and easy to detach.

8. The elastic connecting assembly is used for providing pre-tightening force between the pressing piece and the joint ball, so that adjustable and stable static friction force and dynamic friction force are formed between the pressing piece and the joint ball, the sample holder and the pressing piece are supported by the static friction force, the influence of gravity on the movement of the sample is reduced, and the displacement control precision is improved; the nano positioner has the advantages of small number of parts, concise and clear connection relation, easy production, and easy adjustment and calibration; the concave groove is matched with the joint ball, the position between the pressing piece and the joint ball is stable, the connection relation between the pressing pieces is stable, and the nano positioner is prevented from falling off.

Drawings

FIG. 1 is a schematic view of a sample rod.

Fig. 2 is a schematic view of a piezoelectric ceramic tube.

Fig. 3 is a graph of the effect of observing the region to be observed of the sample under a transmission electron microscope according to the present invention, wherein a.b.c is a large step motion of a single step under a large saw tooth crest-to-peak drive, and d.e.f is a small step motion of a single step under a small saw tooth crest-to-peak drive.

Fig. 4 is a schematic view of a first sample holder.

Fig. 5 is a schematic view of a second sample holder.

Fig. 6 is a schematic view of a third sample holder.

Fig. 7 is a schematic view of a fourth sample holder.

Fig. 8 is a schematic illustration of static discharge.

Fig. 9 is a schematic view of the installation of the conductive screw.

Fig. 10 is a schematic view of a sample jaw.

FIG. 11 is a schematic view of the engagement of the pallet and the platen.

Fig. 12 is a schematic view of the structure of the platen.

Fig. 13 is a schematic view of a drive unit distribution.

Fig. 14 is a schematic view of a platen having a drive unit.

Fig. 15 is a schematic view of a three-point drive spindle.

Fig. 16 is a schematic view of the skeleton structure.

Fig. 17 shows a first arrangement of piezoceramic wafers and electrodes.

Figure 18 is a second piezoceramic wafer and electrode arrangement.

Fig. 19 is a schematic view of detecting the position information of the rotating shaft.

FIG. 20 is a schematic diagram of a backbone with fiber grooves.

FIG. 21 is a schematic view of a carcass with a wire guide channel.

FIG. 22 is a schematic view of a sample rod with a housing.

Fig. 23 is a table comparing the performance of the present invention with that of a prior art sample rod.

The labels in the figure are: the driving member 101, the ball seat 102, the joint ball 103, the elastic connection assembly 104, the pressing member 105, the sleeve 106, the static electricity leading-out member 107, the screw hole 1071, the recess 1051, the connection portion 1052, the first pressing member 1053, the second pressing member 1054, the pre-tightening screw 1061, the cone 1062, the base 1063, the gasket 1064, the tightening screw 1065, the sample 1066, the screw 1041, the spring 1042, the mounting hole 1043, the conductive region 1011, the whole area conductive portion 1012, the clamping tip 108, the clamping portion 1081, the connection portion 1082, the sample mounting hole 1083, the buffer gap 1084, the housing 109, the supporting block 1092, the inclined surface 10921, the pressing plate 1093, the flat plate 10931, the slope 10932, the mounting wing 10933, the fixing hole 10934, the rotation shaft 110, the magnet 1101, the magnetic field sensor 1103, the flat surface portion, the bending portion 1105, the lead-out circuit board 1106, the driving ceramic sheet 111, the substrate 1111, the piezoelectric ceramic sheet 1112, the area 1113, the optical fiber connector comprises a first electrode plate 1117, a second electrode plate 1119, a third electrode plate 1120, a framework 112, a matching part 1121, a receiving groove 1122, a mounting part 1123, a connecting circuit board 1124, a mounting cavity 1125, a threaded hole 1126, an optical fiber groove 1127, a wire passing groove 1128, a front end circuit board 1129, an optical fiber 1130, a mounting block 1132, a guide plane 1133, an adapter circuit board 1131, a wear-resistant layer 113, an elastic mounting component 114, a screw 1141 and a spring 1142.

Detailed Description

FIG. 1 is a multi-degree of freedom sample rod. As shown in fig. 2, a nano positioner is arranged on the sample rod, the nano positioner comprises a driving member 101, a joint ball 103 and a pressing member assembly, the joint ball 103 is fixed with the driving member 101, the pressing member assembly comprises at least two pressing members 105 and an elastic connecting assembly 104, the elastic connecting assembly 104 connects adjacent pressing members, the pressing member assembly embraces the joint ball 103, and a pre-tightening force is provided between the pressing members and the joint ball 103. Such as a piezo ceramic tube, as the driver 101.

Casting die

In some embodiments, as shown in FIG. 2, each compression element has a depression 1051 and a web 1052, respectively, with the resilient linkage assembly 104 disposed between the webs 1052 of adjacent compression elements, with the depressions 1051 of all compression elements forming pockets for mating with the joint balls 103. The dimples are in line contact or surface contact or point contact with the joint ball 103; the elastic connection assembly 1052 pre-loads the pressing element and the joint ball 103, and when the joint ball 103 is at rest or the driving element 101 carries the joint ball 103 to move slowly, the static friction force between the joint ball 103 and the pressing element 105 makes the pressing element 105 to be at rest relative to the joint ball 103. When the driving element 101 carries the joint ball 103 to reset rapidly, sliding friction force is generated between the joint ball 103 and the pressing piece 105, and when the joint ball 103 resets, the pressing piece 105 keeps in a normal position and does not reset along with the joint ball 103, or although reset motion is generated along with the joint ball 103, the motion stroke is smaller than the joint ball reset stroke.

The dimples are hemispherical, or V-shaped, or conical.

The pressing member 105 is a one-piece plate body, and the recessed portion 1051 is located in the center of the plate body.

The pressing member 105 is located outside the joint ball 103. When the sample rod is vertically placed, the nanometer positioner faces upwards, and the two sides are the outer sides of the sample rod in the vertical placement, left, right, front and back. Preferably, the pressing member 105 is provided with a sample holding portion. When all the pressing pieces are assembled in place, the sample holding parts are combined into a sample clamp, and the sample clamp is used for installing samples. When the device is installed, the pressing piece 105 is used for holding the joint ball 103 from two sides of the joint ball 103, and the elastic connecting component 104 provides pre-tightening force between the pressing piece 105 and the joint ball 103.

As shown in fig. 2-5, in some embodiments, the pressing member includes a first pressing member 1053 and a second pressing member 1054, a plurality of mounting locations are uniformly distributed around the recessed portion 1051 of the first pressing member 1053 and the recessed portion 1051 of the second pressing member 1054, each mounting location corresponds to one of the elastic connection assemblies 104, and the mounting location of the first pressing member 1053 is aligned with the mounting location of the second pressing member 1054. In this way, the elastic connection member 104 has one end mounted to the mounting position of the first pressing member 1053 and the other end mounted to the mounting position of the second pressing member 1054. The first follower 1053 is on top and the second follower 1054 is on bottom, and the recess of the second follower 1054 is a through hole. The inner wall of the through hole is in a hemispherical shape, a V shape or a conical shape, etc. The first pressing piece 1053 is provided with a sample holder.

Alternatively, the first pressing member 1053 and the second pressing member 1054 are located on both sides of the joint ball 103, respectively.

The surface of the concave part 1051 of the first pressing piece 1053 is provided with a wear-resistant layer. The surface of the concave part 1051 of the second pressing piece 1054 is provided with a wear-resistant layer 113. The wear resistant layer is beneficial to keeping the friction stable. The surface of the joint ball 103 is provided with a wear-resistant layer, or the joint ball 103 is made of a wear-resistant material. For example, aluminum or an aluminum alloy, and anodizing the surface of the recess and/or the surface of the joint ball.

When the driving member swings to the left side (or right side, front side, rear side), the nano positioner moves to the side by friction force, and the sample moves to the side. The distance of movement of the sample is proportional to the voltage value of the opposing constant voltages applied to the two sheets of conductive coating. The position of the sample is repeatedly observed, and the voltage value is adjusted according to the position, so that the sample moves to a required position.

Elastic connecting assembly

As shown in fig. 2-5, in some embodiments, the resilient connecting member 104 is a spring or a resilient column (e.g., a silica gel column, a rubber column, etc.) made of resilient material, and the resilient connecting member 104 is fixed to the first pressing member 1053 at one end and the second pressing member 1054 at the other end. After the two pressing pieces hold the joint ball 103, the elastic connecting assembly 104 is in a deformation state, and the restoring force of the elastic connecting assembly 104 provides a pre-tightening force between the two pressing pieces and the joint ball 103.

Or, the elastic connecting assembly is composed of a screw 1041 and a spring 1042, the spring 1042 is sleeved on the screw 1041, the spring 1042 is located between the screw 1041 and the first pressing member 1053, and the installation position of the second pressing member 1054 is a screw hole engaged with the screw 1041. After the screw 1041 is engaged with the mounting position of the second pressing member 1054, the spring 1042 is in a compressed state, the spring 1042 pushes the first pressing member 1053 toward the second pressing member 1054, and the spring 1042 provides a pre-tightening force between the first pressing member 1053, the second pressing member 1054 and the joint ball 103. The mounting position of the first pressing piece 1053 is a through hole, and the through hole is in clearance fit with the screw 1041. There is no friction between the through hole and the screw 1041, which is beneficial for the spring 42 to push the first pressing piece 1053.

In some embodiments, the screw 1041 extends out of the mounting hole 1043 of the second pressing member 1054, or there is a fixing portion between the screw 1041 and the second pressing member 1054; or the screw 1041 passes through the first pressing piece 1053 and the second pressing piece 1054 in sequence to be meshed with the nut. For example, after the second pressing member 1054 is mounted in place, the screw 1041 and the second pressing member 1054 are welded or bonded, or the screw thread on the screw is broken. This is because when the joint ball 103 moves circularly to drive the first pressing piece 1053 and the second pressing piece 1054 to displace, the first pressing piece 1053 and the second pressing piece 1054 swing to cause vibration between the screw 1041 and the second pressing piece 1054, which causes the screw 1041 to loosen or even separate from the second pressing piece 1054; loosening of the screw 1041 will affect the precise control of the position; the screw 1041 disengages from the second pressing piece 1054, which causes the first pressing piece 1053 and the sample to fall off, and damages the electron microscope. The screw and the second pressing piece are fixed, or a nut is arranged, and a thread of a redundant section is reserved, so that the impact of the swinging of the nanometer positioner is buffered or resisted, the nanometer positioner and a sample are prevented from falling off due to the fact that the screw is separated from the second pressing piece 1054, and the stable connection between the pressing piece and the joint ball 103 is maintained.

The pretightening force between the pressing piece and the joint ball 103 is adjusted by the screwing degree of the screw 1041 in a screw 1041 and spring 1042 mode, and the design and manufacture requirements on elasticity are reduced. The resilient linkage assembly 104 provides a constant, stable pressure between the compression element and the ball 103, thereby allowing a stable frictional force between the compression element and the ball 103.

Driving member

As shown in fig. 2, in some embodiments, the driving member 101 is a piezoelectric ceramic tube, which is a hollow tube body, one end of the piezoelectric ceramic tube is fixed with the joint ball 103, and the other end is mounted on the sample rod; the piezoelectric ceramic tube has an inner surface and an outer surface, and a plurality of conductive area groups are arranged on one surface of the piezoelectric ceramic tube, as shown in fig. 6, each conductive area group includes two symmetrical conductive areas 1011, all the conductive areas 1011 are independent of each other, and each conductive area 1011 has a conductive wire; the other surface of the piezoelectric ceramic tube is a full area conductive portion 1012. The full area conductive portion 1012 means that the conductive coating completely covers the other surface.

As shown in fig. 2, the conductive regions are disposed on the outer surface of the piezo ceramic tube, and the entire region conductive part 1012 is disposed on the inner surface of the piezo ceramic tube. Alternatively, the conductive regions 1011 are arranged on the inner surface of the piezoelectric ceramic tube, and the entire region conductive part 1012 is arranged on the outer surface of the piezoelectric ceramic tube. If the sets of conductive regions are uniformly distributed along the outer (inner) surface of the piezo-ceramic tube, the entire region conductive portion 1012 covers the inner (outer) surface. There is an insulating coating between adjacent conductive areas 1011. The two conductive areas 1011 of each conductive area group have opposite voltage directions.

In some embodiments, as shown in fig. 3, the joint ball 103 is connected to the piezo ceramic tube by a ball seat 102, and the ball seat 102 includes a connection rod fixed to the joint ball 103 and a connection seat fixed to the piezo ceramic tube, the connection rod having a diameter smaller than that of the joint ball 103. The connecting rod is detachably fastened and connected with the connecting seat. Such as a threaded connection, keyed connection, etc. During installation, the connecting rod penetrates through the groove through hole of the second pressing piece, the groove of the second pressing piece is in contact with the joint ball, and then the connecting rod is fixed with the connecting seat. Therefore, the second pressing piece is convenient to disassemble, assemble and replace.

The bottom end of the piezoelectric ceramic tube is fixed, one conducting wire is welded to the conducting coatings on the inner side face of the piezoelectric ceramic tube and is kept grounded, four conducting wires are respectively welded to the four conducting coatings on the outer side face of the piezoelectric ceramic tube, the other end of each conducting wire is connected to each output end of the voltage amplifier, and then each input end of the voltage amplifier is connected to the function signal generator. The two degrees of freedom of the sample rod can be driven separately. The method for driving the sample rod to move to a required position in any degree of freedom comprises the following steps: and applying sawtooth waves with opposite positive and negative polarities to the two symmetrical conductive coatings on the outer side surface of the piezoelectric ceramic tube through a lead. The sawtooth wave may be continuous or may be pulsed, as shown in fig. 3. The more conductive areas 1011, the more possible directions of movement of the joint ball 103.

As shown in FIG. 3, the parameters of the continuous sawtooth wave are preferably 100V peak-to-peak, 100Hz frequency or less, and 100V/μ s slew rate or more. A suitable reduction in peak-to-peak value may reduce the motion step, but too low a peak-to-peak value (in some cases, below 40V) may cause the motion step to drop sharply to zero, as may be related to the microstructure of the friction face. When the peak-to-peak value is higher than 100V, the piezoelectric ceramic is broken down, and the piezoelectric ceramic tube is damaged. When the frequency is higher than 100HZ, the intrinsic vibration of the piezoelectric ceramic tube or the whole device structure can be excited, so that the motion of the joint ball 103 is no longer 'slow and fast' motion in a plane, the driving principle of the nano positioner cannot be met, and the sample cannot move. The reduction of the frequency can reduce the number of movement steps generated in unit time and control the movement speed of the sample. When the slew rate is lower than 100V/mus, the motion acceleration of the joint ball 103 in the sliding stage is too small, the friction force can keep the motion part to move along with the joint ball 103 without sliding, and the sample cannot generate long-stroke motion by accumulating steps.

When the sample is moved to the vicinity of the target position, opposite constant voltages are applied to the symmetrical conductive regions, so that one side of the piezoelectric ceramic tube is elongated and the other side of the piezoelectric ceramic tube is shortened to be bent as a whole, and thus the joint ball 103 fixed to one end of the piezoelectric ceramic tube is moved to one side.

In some embodiments, the connecting rod and the connecting seat are detachably fastened. Such as a threaded connection, keyed connection, etc. Therefore, the first pressing piece is convenient to disassemble, assemble and replace.

As shown in fig. 4, the sample holder is a sleeve 106, the sleeve 106 is integrated with the first pressing member 1053, and a pretension screw 1061 is installed through the wall of the sleeve 106. The rod-shaped or tubular sample is inserted into the sleeve 106, and the sample is pressed by the pre-tightening screw 1061, so that the sample is clamped.

In another form of the sample holder shown in fig. 5, the sample holder is a cone 1062 integral with the first follower 1053. And gluing the powdery sample on the vertex of the cone 1062 to finish the clamping of the sample.

In another form of the sample holder shown in fig. 6, the sample holder comprises a base 1063, a spacer 1064 and a fastening screw 1065; the base body 1063 is divided into a connecting part and a clamping part, the connecting part is a cylinder fixed with the first pressing part, the clamping part is an incomplete cylinder with a plane, the gasket 1064 is fastened on the clamping part through a fastening screw 1065, and a sample 1066 is clamped between the plane of the clamping part and the gasket 1064.

In another form of the sample holder shown in fig. 7, the sample holder comprises a nozzle 108 and a sleeve 106, the nozzle 108 being located in the sleeve 106, the sleeve 106 being integral with the first follower 1053, and a pretensioning screw 1061 being mounted through the wall of the sleeve 106. The rod-shaped or tubular sample is inserted into the clamping nozzle 108, and the clamping nozzle 108 is pressed by the pretightening screw 1061, so that the sample is clamped.

Electrostatic discharge

In some embodiments, as shown in fig. 8 and 9, when the sample is a conductor or a semiconductor, a sleeve 106 for loading the sample is disposed at a head end of the nano-actuator, a pre-tightening screw 1061 for locking the sample is disposed on the sleeve, a static electricity leading-out member 107 is disposed at a tail end of the nano-actuator, the pre-tightening screw 1061 and the static electricity leading-out member 107 are capable of conducting electricity, an electrical path for communicating the pre-tightening screw 1061 and the static electricity leading-out member 107 is disposed on the nano-actuator, and the static electricity leading-out member 107 is connected to a wire, which is grounded, or connected to a constant voltage power supply provided by an external device, or connected to a rod body of. In this way, static electricity on the region to be observed of the sample is transmitted to the pre-tightening screw 1061 through the sample, the pre-tightening screw 1061 reaches the static electricity leading-out member 107 through an electric path on the nano-actuator, and current on the static electricity leading-out member 107 is led out through the lead.

As a specific example, the electrical path may be a wire connecting the pre-tightening screw 1061 and the electrostatic lead-out 107, and it is only necessary to make the length of the wire redundant so that the wire does not affect the activity of the nano-actuator. Or, the nano-actuator adopts the above structure, as shown in fig. 8 and 9, the sleeve 106 is disposed on the first pressing member 1053, the electrostatic lead-out member 107 is fixedly mounted on the second pressing member 1054, the first pressing member 1053, the sleeve 106 and the second pressing member 1054 are all conductors, at least one elastic connection assembly 104 is disposed between the first pressing member 1053 and the second pressing member 1054, the elastic connection assembly 104 includes a screw 1041 and a spring 1042, the spring 1042 is sleeved on the screw 1041, the screw 1041 and the spring 1042 are all conductors, and the surface of the through hole corresponding to the screw 1041 of the first pressing member 1053 is kept conductive. Thus, the flow direction of the static electricity is: sample → preloaded screw → first presser → spring → screw → second presser → electrostatic conductive ejector.

In one embodiment, the static discharge element 107 is a conductive screw, the second pressing element 1054 has a threaded hole for engaging the conductive screw, the nut of the conductive screw faces away from the first pressing element 1053, and the conductive wire is positioned between the nut of the conductive screw and the second pressing element 1054. This is because this allows for the installation of a conductive screw, securing the wire to the conductive screw. The screw portion of the conductive screw is located within the second presser 1054. That is, the conductive screw is located in the second pressing member 1054 except for the head, and the tail portion thereof does not protrude from the second pressing member 1054 and is not screwed into the first pressing member 1053. In this manner, relative movement between the first pressing member 1053, the joint ball 103, and the second pressing member 1054 is prevented from affecting the stability of the conductive screw. The tail of the conductive screw is fixed to the second pressing member 1054 by spot welding. The spot welding fixes the conductive screw in the second pressing member 1054, so that the stability of current transmission is maintained, and the conductive screw is prevented from being separated from the second pressing member 1054 and falling off. The transmission electron microscope is very expensive and difficult to maintain, once a part or a sample and the like fall off in a sample cavity of the transmission electron microscope, huge loss is caused, the space of the sample cavity is limited, and the falling part is difficult to take out, so that the connection reliability of each part of the sample rod is very important. The head of the conductive screw is exposed to the second pressing member 1054. Thus, the wire can be compressed between the conductive screw and the surface of the second pressing member 1054 without being embedded in the screw hole of the second pressing member 1054, and the wire is not easily broken.

Sample clamping nozzle

The sample needs to be loaded on the sample rod. For example, the sample is a bar with a diameter of 0.3mm and a length of 10 mm. And the region to be observed of the sample is a region with a thickness of 100nm or less at one end of the sample, such as a needle tip or attached nanoparticles. There may be one or more regions to be observed on each sample. When a sample observation experiment is carried out, a sample rotates around a shaft, and in order to keep a region to be observed of the sample in an observation visual field of a transmission electron microscope all the time, the region to be observed of the sample needs to be close to the rotating shaft as much as possible. The typical way to mount the sample is: the front end of the sample rod is provided with a sleeve, the pre-tightening screw presses the sample on the wall of the sleeve from one side, and in order to enable the sample to be smoothly and nondestructively installed in the sleeve, the inner diameter of the sleeve needs to be thicker than that of the sample, so that the area to be observed of the sample inevitably deviates from the central axis of the sample rod. However, the observation scale of the transmission electron microscope is usually micron-scale or nanometer-scale, and when the region to be observed of the sample is observed, it is likely that the region to be observed of the sample after the sample is rotated by the piezoelectric rubbing mechanism exceeds the observation field of the transmission electron microscope. In order to observe samples with various sizes, the sample clamping nozzle is arranged for installing the samples, and the samples and the sample clamping nozzle are arranged at the front end of the sample rod as sample components, so that the sample rod is convenient to install and disassemble.

Preferably, as shown in fig. 10, the sample nozzle 108 includes a grip portion 1081 and a connecting portion 1082, and the sample is loaded on the grip portion 1081. The thread position in the clamping portion has a sample loading hole 1083, and the sample is loaded in the sample loading hole 1083. When clamping the sample, partially inserting the sample into the copper tube, and then clamping one end of the inserted copper tube with a tool (such as a pliers) to make the inner surface of the section of copper tube fit with the sample to form an arch, which is a clamping portion 1081, so as to limit the sample at the arch and complete the assembly of the sample and the sample clamping nozzle 108. The connecting portion 1082 of the sample holder is clearance fit with the sleeve 106. If the sleeve 106 is circular, the connecting portion 1082 is cylindrical, so long as the connecting portion 1082 is capable of clearance-fitting with the sleeve 106. Therefore, the pre-tightening screw 1061 directly abuts against the sample clamping mouth, samples of any size can be installed on the sample clamping mouth, and then the sample assembly is installed on the sample rod, so that the universality of samples which can be loaded on the sample rod is good. The pre-tightening screw 1061 only needs to be abutted against the sample clamping mouth, the pre-tightening screw 1061 does not contact with the sample, the sample is not damaged, and the installation gap between the sample clamping mouth 108 and the sample rod can be set to be as small as possible, so that the sample is ensured to be as close as possible to the sample rod shaft.

As a specific embodiment, the two sides of the sample loading hole 1083 are symmetrically provided with buffer gaps 1084 communicated with the sample loading hole 1083. When the size of the loading hole 1083 is smaller than the size of the sample, the buffer gap 1084 allows the loading hole 1083 to have a space with an increased size, thereby smoothly loading the sample into the loading hole 1083. The clamp portion 1081 is tapered from the bottom to the top, with the top flat. The flat top reduces the space occupied by the sample clamping mouth 108, and is convenient for sample operation. The clamp portion 1081 is hollow. The hollow-shaped clamp portion 1081 can increase the depth of the sample.

As a specific example, the clamping portion 1081 and the connecting portion 1082 are fixedly connected or integrally formed, the clamping portion 1081 is located above the connecting portion 1082, the connecting portion 1082 is a solid column, or the connecting portion 1082 is hollow. Here, the fixed connection means a welding method or the like. When the connecting portion 1082 is a solid column, the solid column is not prone to extrusion deformation, and the pre-tightening screw 1061 abuts against the solid column, so that the reliability of installation of the sample-sample clamping nozzle is maintained. When the connecting portion 1082 is hollow, the depth of the sample can be further increased, and the manufacturing cost of the sample holder 108 can be reduced.

Preferably, the connecting portion 1082 has a recess therein. The pre-tightening screw 1061 is correspondingly inserted into the concave of the connecting part 1082, so that the connecting part 1082 is locked, and the sample can be prevented from rotating and moving.

The sample jaw 108 is a conductor. Thereby facilitating the outward conduction of static electricity accumulated on the region to be observed of the sample. The sample jaw 108 may be a thin-walled copper tube. The thin-wall copper tube is used, so that the manufacturing cost is low, and the thin-wall copper tube can be adapted to samples with different sizes. When the sample rod has a clamping mouth, the electrostatic flow direction is as follows: sample → clamp mouth → preloaded screw → first presser → spring → screw → second presser → static conductive ejector.

Method for adjusting sample to align with axis of rotating shaft

s1, manufacturing the sample clamping mouth, clamping a sample in the sample clamping mouth, and then installing the sample clamping mouth into a sample clamp of a sample rod;

s4, driving the nanometer positioner to drive along the Y direction, and moving the position of the sample characteristic point projected on the electron microscope screen to the central position Dz of D1 and D2;

Self-positioning of sample rod axis

In order to realize the rotation of the sample around the shaft by 360 degrees, the sample rod is arranged to comprise a shell 109 and a rotating shaft 110, the shell 109 and the rotating shaft 110 are coaxial, and the rotating shaft 110 is positioned in an inner cavity of the shell 109; the inner cavity is provided with a piezoelectric twisting mechanism for twisting the rotation of the rotating shaft and a self-positioning mechanism, the self-positioning mechanism is provided with symmetrical inclined planes, and the inclined planes are in contact with the rotating shaft. No matter how the rotating shaft rotates, the central shaft of the rotating shaft can be automatically reset to the original position due to the function of the inclined surface, so that the phenomenon that the area to be observed of the sample is separated from the observation visual field of the transmission electron microscope due to the central displacement of the rotating shaft 110 is avoided. Preferably, the rotating shaft 110 is a ceramic shaft.

Preferably, the self-positioning mechanism includes a holder 1092, as shown in FIG. 11, the holder 1092 having a symmetrical ramp 10921, the ramp of the holder 1092 contacting the shaft 110. Preferably, the inclined surface 10921 of the supporting block 1092 has a wear-resistant layer 113, and the wear-resistant layer 113 is a contact portion with the rotating shaft 110. Preferably, a plurality of supporting blocks 1092 are distributed along the axial direction of the rotating shaft 110.

Preferably, the self-positioning mechanism includes a pressure plate 1093, as shown in fig. 11 and 12, the pressure plate 1093 has a flat plate 10931, and a ramp 10932 is symmetrically disposed on both sides of the flat plate 10931. The rotation shaft 110 is restricted between the holder 1092 and the presser plate 1093, so that the rotation shaft 110 does not move up and down and left and right when rotating around the shaft. Preferably, each pallet 1092 corresponds to a platen 1093, with pallet 1092 below and platen 1093 above. Alternatively, the self-positioning mechanism includes a plurality of pallets 1092 and a platen 1093.

As shown in fig. 12, the pressure plate 1093 has a pair of mounting wings 10933, and the mounting wings 10933 have fixing holes 10934; the mounting wing 10933 is located at one end of the ramp 10932. The inner side of the flat plate is provided with a wear-resistant layer 113, and the wear-resistant layer 113 is a contact part with the rotating shaft 110.

A framework 112 is arranged between the shell 109 and the rotating shaft 110, and the mounting wings 10933 are assembled on the framework 112 through elastic mounting components 114. As shown in FIG. 12, resilient mounting assembly 114 is comprised of a threaded rod 1141 and a spring 1142, with spring 1142 being received around the shank of threaded rod 1141 and spring 1142 being located between mounting wing 10933 and the nut of threaded rod 1141. The elastic mounting assembly 114 enables the pressing plate 1093 to slightly move along the radial direction of the rotating shaft 110, so as to pre-tighten the rotating shaft 110 and enable the rotating shaft 110 to rotate. The shaft 110 is constrained between the pressure plate 1093 and the bracket 1092, and the amount of preload is adjusted by rotating the screw 1141 during assembly. After assembly, the spring 1142 does not continue to deform during use.

Rotating shaft driving assembly

As a preferable scheme, at least one set of rotating shaft driving components is arranged between the framework 112 and the rotating shaft 110, the rotating shaft driving components are piezoelectric twisting mechanisms, each set of rotating shaft driving components comprises a driving unit, the driving unit comprises a substrate and a piezoelectric ceramic piece, the substrate is an insulator, or the substrate is a PCB.

One proposal of driving the rotating shaft to rotate: the rotation shaft driving assembly comprises an autorotation driving unit, the shearing deformation direction of a piezoelectric ceramic piece of the autorotation driving unit is consistent with the annular direction of the rotation shaft 110, the piezoelectric ceramic piece is bonded on the substrate, and the surfaces of two sides of the piezoelectric ceramic piece are coated with conductive coatings. When the conductive coating is driven, a voltage signal is input between the conductive coatings, such as continuous or discontinuous sawtooth waves.

The deformation direction of the first piezoelectric ceramic piece is orthogonal to the deformation direction of the second piezoelectric ceramic piece, for example, the deformation direction of the first piezoelectric ceramic piece is along the axial direction of the rotating shaft (i.e., the front-back direction) and is used for driving the rotating shaft 110 to translate back and forth, and the deformation direction of the second piezoelectric ceramic piece is along the circumferential direction of the rotating shaft (i.e., the rotation direction) and is used for twisting the rotating shaft 110 to rotate. The first piezoelectric ceramic sheet is superposed on the second piezoelectric ceramic sheet, or the second piezoelectric ceramic sheet is superposed on the first piezoelectric ceramic sheet; the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are fixedly bonded. The drive unit is provided with a wear layer 113. The wear-resistant layer 113 is directly contacted with the rotating shaft 110, so that the wear is reduced, and the service life of the driving unit is prolonged. One side surface of the first piezoelectric ceramic piece is communicated with one side surface of the second piezoelectric ceramic piece to share one lead.

Preferably, the shaft drive assemblies are arranged in two or three sets axially along the shaft 110. The set of the rotating shaft driving assemblies limits the force of the rotation and the axial movement of the rotating shaft, and the plurality of sets of the rotating shaft driving assemblies apply the force in the same direction to the rotating shaft 110, so that the rotation and the axial movement of the rotating shaft are facilitated. However, if the rotary shaft driving component is arranged too much, the force application is easy to be disturbed.

Scheme of two points driving the rotating shaft: the front end of the rotating shaft is provided with a group of rotating shaft driving assemblies along the axial direction, the group of rotating shaft driving assemblies comprises two groups of driving units which are symmetrically arranged along the rotating shaft, the left side and the right side of the rotating shaft are respectively driven by driving force provided by the driving units, the wear-resistant pieces on the surfaces of the two driving units are flush with the contact point of the rotating shaft 110, see fig. 13, and a and b in the figure are respectively two groups of driving units 111.

The scheme of three-point driving rotating shaft is as follows: when the two sets of the rotating shaft driving components are arranged, the front end of the rotating shaft 110 is provided with a set of rotating shaft driving components along the axial direction, and the front end rotating shaft driving components comprise two sets of driving units symmetrically arranged along the rotating shaft. A set of spindle driving components is disposed between the pressing plate 1093 and the spindle 110, and the set of spindle driving components includes a set of driving units. The pressure plate 1093 is located above the two sets of drive units, and the wear-resistant plates on the surfaces of the three sets of drive units are flush with the contact point of the rotating shaft 110, i.e., axially flush. If the contact point is staggered along the axis of the rotation shaft 110, the rear end of the rotation shaft 110 is easily tilted. The pressing plate 1093 is transversely provided with through holes, copper foils penetrate through the through holes, the copper foils are used as lead-out media of the electrodes of the driving units and are connected with external leads, see fig. 15, wherein a, b and c are three groups of driving units 111 respectively.

The scheme of five-point driving rotating shaft: when the rotating shaft driving assemblies are arranged into five groups, two groups of rotating shaft driving assemblies are respectively arranged at the front end and the rear end of the rotating shaft 110 along the axial symmetry, and each group of rotating shaft driving assemblies comprises two groups of driving units which are symmetrically arranged along the rotating shaft. A set of driving components for the rotating shaft is disposed in the middle of the rotating shaft 110, and the driving components for the rotating shaft include a set of driving units, which are disposed between the pressing plate 1093 and the rotating shaft 110. The wear-resistant pieces on the surfaces of the two sets of driving units at the front end and the rear end of the rotating shaft 110 are flush with the contact points of the rotating shaft 110, see fig. 13, wherein a, b, c, d, e in the figure are five sets of driving units 111 respectively.

Framework

As shown in fig. 21, the frame 112 is disposed between the housing 109 and the rotating shaft 110, and the frame 113 is coaxial with the housing 109 and the rotating shaft 110. The framework 112 is used as a transition part between the rotating shaft 110 and the shell 109, when the rotating shaft 110 and the framework 112 are assembled, the rotating shaft-framework is installed in the shell, and the rotating shaft 110, the framework 113 and the shell 109 are coaxial, so that the installation accuracy is improved. In addition, the framework 112 also provides a mounting position for the rotating shaft driving assembly, and the framework 112 also plays a role in separating the rotating shaft from the lead and avoiding the lead from interfering with the movement of the rotating shaft.

As shown in fig. 16, the frame 112 has a matching portion 1121 in clearance fit with the inner wall of the housing 109, a receiving groove 1122 for receiving the rotation shaft, and a mounting portion 1123 for carrying a fitting, the receiving groove 1122 has symmetrical inclined surfaces, a connection circuit board 1124 is fixed on the mounting portion 1123, and a connection lead is provided on the connection circuit board 1124. The connecting circuit board is a PCB printed circuit board.

The support block 1092 is fixed to the receiving groove 1122, and the receiving groove 1122 is provided with a plurality of sections along the axial direction of the framework 112; the framework 112 is provided with a mounting cavity 1125 for accommodating the spindle driving assembly, and the accommodating grooves 1122 and the mounting cavity 1125 are distributed at intervals. After the rotating shaft driving assembly is installed in place, the wear-resistant layer of the rotating shaft driving assembly forms an inclined plane for limiting the rotating shaft.

Each driving unit is provided with a connecting circuit board 1124 for current circulation, the connecting circuit board is a PCB printed circuit board, and a circuit electrically communicated with the rotating driving component is arranged on the connecting circuit board 1124; each rotating shaft driving component corresponds to one adapter circuit board 1131, the adapter circuit board 1131 is a PCB, and the adapter circuit board 1131 is provided with a communication line; the current of the connecting circuit board 1124 is collected to the connecting circuit board 1131, the adapting circuit board 1131 is connected with the transmission lead, and the transmission lead is connected with the signal connector on the sample rod. The signal connector is connected with an external signal source and outputs a control signal. The mode of adopting the circuit board realizes the signal of telecommunication transmission, avoids the wire to disturb the pivot and rotates.

As a specific embodiment, the adapting circuit board 1131 is fixed to the frame 112, and the rotating shaft 110 is located below the adapting circuit board 1131, see fig. 13. Adapter circuit board 1131 is located between pressure plate 1093 and the spindle drive assembly. The adapting circuit board 1131 is a PCB printed circuit board, the area of the solderable region of the driving unit 111 is limited, and soldering is not firm, so that the adapting circuit board 1131 can reduce the contact of the conductive wires on the driving unit in the assembling process to protect the soldering points. 6 leads (including 9 leads in total for the driving units below the pressing plate in three-point driving) led out from the left and right driving units of the switching circuit board 1131 are connected into 3 leads, so that the electrical connection is simplified.

Preferably, the connection circuit board 1124 and the relay circuit board 1131 are electrically connected by a wire.

Preferably, the framework 112 is cylindrical, a groove is cut on one side of the framework 112, the groove penetrates through the framework 112 in the axial direction, and the accommodating groove 1122 and the mounting cavity 1125 are both located on the groove; the arc surface of the frame 112 is used as the bottom, the opening of the groove is used as the top, a gap is arranged at the position where the connecting circuit board 1124 is placed, and part of the frame wall is cut off from the top downwards to form the gap. The walls at the two ends of the gap serve to locate the connection circuit board 1124.

Preferably, the width of each connection circuit board 1124 is less than or equal to the wall thickness of the frame, and the connection circuit boards 1124 are fixed to the top surfaces of the notches by screws.

Preferably, the frame wall plane of the mounting relay circuit board 1131 is higher than the frame wall plane of the mounting connection circuit board 1124. Thus, the adapter circuit board 1131 is partially suspended and mounted with the connecting circuit board 1124 therebelow, saving mounting space; moreover, a gap is formed between the relay circuit board 1131 and the connection circuit board 1124, thereby preventing short-circuiting of the wires.

Preferably, as shown in fig. 21, the framework 112 is provided with mounting threaded holes 1126, and the threaded holes 1126 penetrate through the framework 112 from top to bottom. The threaded holes 1126 are through holes that facilitate cleaning the frame 112, keep the sample rod clean, and avoid contamination and interference with the sample cavity in the transmission electron microscope.

Optical fiber access

Preferably, as shown in fig. 20, the optical fiber groove 1127 is opened on a side surface of the bobbin 112, and the optical fiber groove 1127 axially penetrates the bobbin 112. The optical fiber passes through the optical fiber groove 1127, and the optical fiber can be prevented from being abraded.

Preferably, the head of the sample rod is provided with a front end circuit board 1129, the front end circuit board 1129 is connected with the optical fiber groove 1127, and the front end circuit board 1129 and the optical fiber groove 1127 are positioned on the same straight line. The reason why the fiber groove 1127 is opened on the side of the frame 112 is that the head of the sample rod has a front end circuit board 1129, the fiber groove 1127 is connected with the front end circuit board 1129, the front end circuit board 1129 has the function of guiding the optical fiber 1130, and the head of the optical fiber passes through the front end circuit board 1129, so that the head of the optical fiber has a smaller bending amplitude. If the bending amplitude of the optical fiber head is too large, light wave attenuation is caused, and even the optical fiber is broken.

The front-end circuit board 1129 is mounted to the chassis by a mounting block 1132. The mounting block 1132 fixes the front-end circuit board 1129 to the bobbin 112 by bolts. The front end circuit board 1129 has a guide plane 1133 for guiding the optical fiber, and the guide plane 1133 is flush with the optical fiber groove 1127. The guide plane 1133 extends towards the sample holder mouth, and the optical fiber approaches the sample along the guide plane 1133.

Two optical fiber grooves 1127 are symmetrically formed on the frame 112. Accordingly, the front circuit board 1129 has symmetrically arranged guide planes 1133, and the guide planes 1133 are connected with the fiber grooves 1127 one by one. Two optical fiber grooves 1127 are formed, and the optical fiber 1130 can selectively pass through any one optical fiber groove 1127, or two optical fibers 1130 are used, and respectively pass through two optical fiber grooves 1127, for example, different spectrums are passed, or one optical fiber emits light and the other collects light.

As shown in fig. 16, the fiber slot 1127 is in alignment with the connection circuit board 1124. Namely, the connecting circuit board is arranged along the route of the optical fiber groove 1127, the lead-out wires of the connecting circuit board 1124 can be led out from the inner wall of the framework 112, and can also pass through the optical fiber groove 1127, so that the arrangement of the wires does not interfere with the rotation of the rotating shaft 110. The fiber groove 1127 is linear, and the fiber groove 1127 can accommodate at least a 0.5mm diameter fiber.

Electric wire leading-out

The lead of the front end circuit board needs to be connected with an external control box, the lead passes through the framework 109 from the outside, long-term contact friction not only causes abrasion to the lead, but also the lead has small diameter, various leads are complicated and are easy to be wound mutually. The bottom of the framework 112 is provided with a wire passing groove 1128 for a lead to pass through, so that the lead can be prevented from being worn and wound.

Preferably, as shown in fig. 21, a wire passing groove 1128 is formed at the bottom of the framework 112, the wire passing groove 1128 axially penetrates through the framework 112, and the wire passing groove 1128 is a groove open to the bottom.

Arrangement of piezoelectric ceramic plates and electrodes

Preferably, as shown in fig. 17, the driving unit 111 includes a substrate 1111, a piezoelectric ceramic plate 1112 and a wear pad 113, the substrate 1111 has a ceramic plate region 1113 and an electrode region 1114, the piezoelectric ceramic plate is stacked and bonded to the ceramic plate region 1113, and the electrode region 1114 has a plurality of traces electrically connected to the conductive coating on the surface of the piezoelectric ceramic plate.

The ceramic plate area 1113 has one piezoceramic plate or at least two piezoceramic plates 1112 are stacked. When there are at least two piezoelectric ceramic sheets 1112, the expansion and contraction directions of the piezoelectric ceramic sheets 1112 are different from each other.

Preferably, the substrate 1111 is a PCB printed circuit board.

Preferably, the substrate 1111 is a metal-based PCB printed circuit board.

Preferably, the substrate 1111 is an aluminum-based PCB printed circuit board. Preferably, the substrate 1111 has a recessed platform and a pair of mounting holes 1116, the mounting holes 1116 are used as the front and rear ends of the substrate 1111, the ceramic sheet region 1113 and the electrode region 1114 are located at the center of the substrate, and the recessed platform is located at the front and rear ends of the substrate 1111 around the mounting holes; ceramic wafer region 1113 and electrode region 1114 are located on the left and right sides of substrate 1111.

Preferably, the lower electrode of the lowest piezoelectric ceramic plate is directly contacted with the ceramic plate region 1113 on the substrate 1111 and is connected to the electrode region 1114 on the substrate 1111 through the circuit on the ceramic plate region 1113; the surface of an upper electrode of the uppermost piezoelectric ceramic piece is provided with an area A and an area B; the A area is adhered with a wear-resistant sheet 113; the area B is electrically connected with a transfer lead; one end of the via wire is electrically connected to the electrode region 1114 on the substrate 1111.

Preferably, when there are at least two piezoelectric ceramic sheets, the upper electrode of each piezoelectric ceramic sheet except the uppermost piezoelectric ceramic sheet has an overlapping region and an exposed region; the overlapping area is electrically connected with the lower electrode of the upper layer of the piezoelectric ceramic sheet of the laminated piezoelectric ceramic sheet; the exposed area is electrically connected with a switching lead; one end of the via wire is electrically connected to the electrode region 1114 on the substrate.

Preferably, the via leads are soldered to the electrode areas 1114 on the substrate 1111.

As shown in fig. 18, the driving unit includes a first electrode plate 1117, a first piezoelectric ceramic piece 1118, and a second electrode plate 1119, where the first piezoelectric ceramic piece 1118 is shear-deformed in the axial direction of the rotating shaft 110, or the first piezoelectric ceramic piece 1118 is shear-deformed in the circumferential direction of the rotating shaft; the first piezoelectric ceramic sheet 1118 is between the first electrode plate 1117 and the second electrode plate 1119, and the first electrode plate 1117 and the second electrode plate 1119 have respective lead terminals, respectively.

Preferably, the driving unit includes a first electrode plate 1117, a first piezoceramic sheet 1118, a second electrode plate 1119, a second piezoceramic sheet 1110 and a third electrode plate 1120; the first electrode plate 1117, the first piezoelectric ceramic piece 1118, the second electrode plate 1119, the second piezoelectric ceramic piece 1110 and the third electrode plate 1120 are sequentially arranged in the mounting sequence; the shear deformation direction of the first piezoelectric ceramic piece 1118 is different from the shear deformation direction of the second piezoelectric ceramic piece 1110; the third electrode plate 1120 is adjacent to the rotation shaft 110 but does not contact the rotation shaft 110.

Preferably, the first electrode plate 1117 is bonded and fixed on the insulating layer, the insulating layer is bonded and fixed on the framework or the housing, and the third electrode plate 1120 is provided with a wear-resistant layer 113 contacting with the rotating shaft. The first, second and third are for illustration purposes only, three electrode plates; the first and second are for illustration purposes only, with two piezoceramic wafers.

Preferably, the first electrode plate, the insulating layer and the framework can be equivalent to a capacitive load in a circuit, and the voltage required for driving each piezoelectric ceramic piece is higher, so that when each piezoelectric ceramic piece is driven by a high-frequency signal, the voltage signal is easy to leak to the framework, and an electron microscope can be damaged. Therefore, the first electrode plate 1117 is kept grounded, and the voltage leakage to the skeleton can be reduced. The second electrode plate 1119 and the third electrode plate 1120 are driven by appropriate voltage signals, so that the required electric field can be obtained without affecting the realization of the driving function.

Position information of the rotating shaft

The end of the rotating shaft is provided with a magnet 1101, the framework 112 is provided with a lead-out circuit board 1106, the magnetic field changes along with the rotation and the back-and-forth movement, the magnetic field sensor measures the magnetic field, and the position information of the rotating shaft can be obtained through solving. The rotation angle of the rotating shaft is measured for processing data after experiments, and a projection angle is needed for three-dimensional reconstruction. The moving distance of the rotating shaft is measured so as to: 1) during experiments, the rotation and the front-back coupling are reduced by using an algorithm, and distance change information is required; 2) during the experiment, the sample is positioned at the position when the sensor is calibrated, so that the error of the angle measurement is smaller. The current sample rod is driven by three degrees of freedom, the sample rod is driven by four degrees of freedom, the axial movement of the rotating shaft is increased, and distance change data are provided for later experiments by measuring the moving distance of the rotating shaft.

The end of the rotating shaft 110 is provided with a magnet 1101, the frame 112 is provided with a lead-out circuit board 1106, the frame 112 is provided with a notch, the lead-out circuit board 1106 comprises a bending portion 1105, the bending portion 1105 is located in the notch, and the magnetic field sensor 1103 is fixed on the bending portion 1105. The magnetic field sensor 1103 is placed in the notch, so that the occupied space is reduced, and the diameter of the shell of the sleeved framework is reduced. The gap has a space much larger than that required for accommodating the magnetic field sensor 1103, and provides a sufficient operating space for disassembling and repairing the magnetic field sensor 1103.

Preferably, the lead circuit board 1106 includes a flat portion 1104, the flat portion 1104 and the bent portion 1105 are bent to cover the frame 112, the flat portion 1104 and the bent portion 1105 are connected by a wire, and the magnetic field sensor 1103 and the bent portion 1105 are soldered. The exit circuit board 1106 is a PCB printed circuit board. The soldering connection between the magnetic field sensor 1103 and the lead-out circuit board 1106 not only can fix the magnetic field sensor 1103, but also can short-circuit one pair of pins on the lead-out circuit board 1106, thereby reducing the number of wires to be connected.

Preferably, the flat portion 1104 and the bent portion 1105 are formed in an "L" shape, and the magnetic field sensor 1103 faces the magnet 1101. The bent circuit board is used, so that the occupied area is small, and the circuit board is easy to disassemble. If the circuit board is not bent, the space is not enough for placing screws, and the circuit board needs to be fixed by gluing and is difficult to disassemble and maintain.

Preferably, the lead-out circuit board 1106 has two sets of lead-out terminals, one set of lead-out terminals being electrically connected with the lead wires of the driving unit 111, and the other set of lead-out terminals being electrically connected with the sample rod.

and S4, importing the picture obtained in the step S3 into a computer, and performing three-dimensional reconstruction. The three-dimensional reconstruction refers to establishing a mathematical model suitable for computer representation and processing on a three-dimensional object, and belongs to the prior art.

Fig. 23 is a table comparing the performance of the present invention with that of a prior art sample rod, which is currently the only four-degree-of-freedom sample rod.

The invention shown and described herein may be practiced in the absence of any element or elements, limitation or limitations, which is specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, and it is recognized that various modifications are possible within the scope of the invention. It should therefore be understood that although the present invention has been specifically disclosed by various embodiments and optional features, modification and variation of the concepts herein described may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

The contents of the articles, patents, patent applications, and all other documents and electronically available information described or cited herein are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. Applicants reserve the right to incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other documents.

Claims

1. The method for adjusting the sample to be aligned with the axis of the rotating shaft is characterized by comprising the following steps of:

s1, manufacturing a sample clamping mouth, clamping a sample in the sample clamping mouth, and then installing the sample clamping mouth into a sample clamp;

s2, inserting the sample rod with the sample into the transmission electron microscope, finding a region to be observed of the sample, and selecting a characteristic point of the region to be observed of the sample;

and S8, increasing the magnification of the transmission electron microscope, and repeating S3-S7.

2. The sample holder of claim 1, wherein: the sample clamping nozzle comprises a clamping part for loading a sample, and a connecting part, wherein a line position in the clamping part is provided with a sample loading hole.

3. The sample holder of claim 2, wherein: two sides of the sample loading hole are symmetrically provided with buffer gaps communicated with the sample loading hole.

4. The sample holder of claim 3, wherein: the clamping part gradually shrinks from the bottom to the top, the top is flat, and the clamping part is hollow.

5. The sample holder of claim 4, wherein: the clamping part and the connecting part are fixedly connected or integrally formed.

6. The sample holder of claim 5, wherein: the connecting part is a solid column or is hollow.

7. The sample holder of claim 6, wherein: the side wall of the connecting part is provided with a pit matched with the pre-tightening screw.

8. The sample holder of claim 7, wherein: the sample clamping nozzle is a thin-wall copper pipe.

9. The sample holder of claim 1, wherein: the sample holder is a sleeve.

10. The nanopositioner of claim 1, wherein: the nanometer positioner comprises a driving piece, a joint ball and a pressing piece assembly, the joint ball is fixed with the driving piece, the pressing piece assembly comprises at least two pressing pieces and elastic connecting assemblies, the elastic connecting assemblies are connected with the adjacent pressing pieces, the joint ball is embraced by the pressing pieces, and pretightening force is arranged between the pressing pieces and the joint ball.