Electron gun adopting horn mouth multi-pole deflection iron core

Abstract

The utility model discloses an electron gun adopting a horn mouth multi-pole deflection iron core, which belongs to the technical field of electron optics, and comprises a cathode assembly, a dynamic focuser, an image eliminator, a focuser and a multi-pole deflector which are sequentially and coaxially arranged along the electron beam propagation direction, the multi-pole deflector comprises a horn-shaped cylindrical iron core, a first insulating framework, a second insulating framework and a coil winding, a first saddle portion of the first insulating framework extends into the iron core from the top, a second saddle portion of the second insulating framework extends into the iron core from the bottom and corresponds to the first saddle portion in a one-to-one mode, and the coil winding is wound on the corresponding saddle portion. And the electron beam deflection horn-shaped space is electrically connected to form a multi-pole structure. According to the utility model, through the horn-shaped space and the multi-pole structure, the uniformity of a magnetic field is improved, aberrations such as off-axis astigmatism and field curvature are reduced, and the harsh requirements of high-resolution and large-size processes such as large-breadth electron beam 3D printing, scanning electron microscopes and electron beam welding on beam spot quality can be met.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electron optics, and specifically relates to an electron gun with a horn mouth multi-pole deflection core. BACKGROUND

[0002] In modern high-precision electron beam application fields, such as electron beam 3D printing, scanning electron microscopes (SEM), electron beam exposure machines (E-beam Lithography), and electron beam welding machines, etc., the electron gun as a core component directly determines the processing size, feature precision, and production efficiency. The current industry-level equipment generally adopts the classic architecture of "pre-focusing + magnetic lens + saddle type deflection coil". In this architecture, the electron beam is compressed by a long magnetic lens and then completes XY scanning by two groups of mutually perpendicular saddle coils. However, this traditional saddle coil has inherent non-uniform magnetic field distribution and edge field decay problems, which leads to the introduction of off-axis astigmatism, field curvature, and pincushion distortion in the deflection process of the electron beam. When the deflection angle exceeds ±5°, the beam spot diameter will rapidly increase, for example, from the 100 nm level to the 1 µm level, which severely limits the single scanning field size, which is usually limited within 50 mm x 50 mm. In order to obtain large-size parts, the existing technology has to adopt the "partition splicing + mechanical displacement table" strategy, which not only sacrifices the production efficiency but also introduces splicing errors, becoming a common bottleneck in large-size electron beam metal 3D printing, 8-inch and above wafer direct exposure, and aero-engine welding applications. This limitation limits the field domain of the electron gun to a very small area, often only printing small precision parts, which cannot meet the manufacturing needs of large-size, high-precision components.

[0003] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0004] It should be noted that this part aims to provide background or context for the technical solutions of the utility model stated in the claims. The description herein is not admitted as prior art merely because it is included in this part. UTILITY MODEL CONTENT

[0005] The purpose of the utility model embodiment is to provide an electron gun with a horn mouth multi-pole deflection core, thereby at least overcoming one or more problems caused by the limitations and defects of related technologies to some extent.

[0006] The utility model embodiment provides an electron gun with a horn mouth multi-pole deflection core, which comprises an electron optical main body part, and the electron optical main body part comprises a cathode assembly, a dynamic focuser, an astigmatism corrector, a focuser, and a multi-pole deflector which are coaxially arranged in sequence along the electron beam propagation direction.

[0007] The multi-pole deflector comprises:

[0008] The iron core is cylindrical and is in a shape of a horn with a top cross section smaller than a bottom cross section;

[0009] The insulation framework comprises a first insulation framework and a second insulation framework;

[0010] The first insulation framework comprises a first annular portion and a plurality of first saddle portions distributed circumferentially along an inner wall of the first annular portion and extending axially downward along the first annular portion, and the plurality of first saddle portions extend into the iron core from a top of the iron core to position the first annular portion at the top of the iron core;

[0011] The second insulation framework comprises a second annular portion and a plurality of second saddle portions distributed circumferentially along an inner wall of the second annular portion and extending axially upward along the second annular portion, and the plurality of second saddle portions extend into the iron core from a bottom of the iron core to position the second annular portion at the bottom of the iron core, and the plurality of second saddle portions correspond to the plurality of first saddle portions one by one;

[0012] A plurality of coil windings are wound on the plurality of first saddle portions and the plurality of second saddle portions corresponding to the plurality of first saddle portions one by one, the plurality of coil windings enclose a horn-shaped space for electron beam deflection, and are electrically connected in sequence to form a multipole structure.

[0013] In an embodiment of the utility model, the inner wall of the iron core is circumferentially distributed with a plurality of protruding walls, and each protruding wall extends from the top of the iron core to the bottom of the iron core;

[0014] The bottom of each first saddle portion is provided with a first channel, and the plurality of first saddle portions of the first insulation framework extend into the iron core from the top of the iron core, are clamped on the top of the plurality of protruding walls through the plurality of first channels, and position the first annular portion at the top of the iron core;

[0015] The top of each second saddle portion is provided with a second channel, and the plurality of second saddle portions of the second insulation framework extend into the iron core from the bottom of the iron core, are clamped on the bottom of the plurality of protruding walls through the plurality of second channels, and position the second annular portion at the bottom of the iron core.

[0016] In an embodiment of the utility model, the multipole deflector further comprises a wire clamp, and the wire clamp comprises a first wire clamp and a second wire clamp;

[0017] The first line card comprises a third annular portion and a plurality of third saddle portions distributed circumferentially along the third annular portion and extending axially downward along the third annular portion, the plurality of third saddle portions extending into the plurality of protruding walls from the top of the iron core, and an outer wall of the third annular portion abutting the coil winding wound on the first saddle portion.

[0018] The second line card comprises a fourth annular portion and a plurality of fourth saddle portions distributed circumferentially along the fourth annular portion and extending axially upward along the fourth annular portion, the plurality of fourth saddle portions extending into the plurality of protruding walls from the bottom of the iron core, and an outer wall of the fourth annular portion abutting the coil winding wound on the second saddle portion.

[0019] In an embodiment of the utility model, the number of the plurality of first saddle portions is 2N, wherein N is an integer greater than or equal to 4 and less than or equal to 12, the number of the second saddle portions is the same as that of the first saddle portions, and the number of the protruding walls is the same as that of the first saddle portions.

[0020] In an embodiment of the utility model, first support plates are arranged between adjacent first saddle portions in the plurality of first saddle portions, and second support plates are arranged between adjacent second saddle portions in the plurality of second saddle portions.

[0021] In an embodiment of the utility model, the multi-pole deflector further comprises a ferrite magnetic ring, the ferrite magnetic ring is horn-shaped, is sleeved on the outer wall of the iron core, and there is a gap of 0.5mm to 1mm between the inner wall of the ferrite magnetic ring and the outer wall of the iron core, and the horn-shaped expansion angle of the ferrite magnetic ring is the same as the horn-shaped expansion angle of the iron core.

[0022] In an embodiment of the utility model, the multi-pole deflector further comprises a shell, the shell is horn-shaped, the horn-shaped expansion angle of the shell is the same as the horn-shaped expansion angle of the ferrite magnetic ring, the shell is sleeved on the outer wall of the ferrite magnetic ring, and a water cooling channel is arranged on the shell.

[0023] In an embodiment of the utility model, the horn-shaped expansion angle is 10°±3°.

[0024] In an embodiment of the utility model, the multi-pole structure is a twenty-pole structure.

[0025] In an embodiment of the utility model, the coil winding comprises a first coil group for generating a magnetic field in the X direction and a second coil group for generating a magnetic field in the Y direction.

[0026] The technical scheme provided by the embodiment of the utility model can have the following beneficial effects:

[0027] The utility model discloses an electron gun of adopting horn mouth multipole deflection core, on one hand, through the horn -shaped core and the coil winding of winding in the first saddle and corresponding second saddle jointly enclose horn -shaped electron beam deflection space, prolongs the effective action path of deflection magnetic field to electron beam, provides the physical basis for electron beam large -angle deflection, reduces the deflection process axis outside astigmatism, field curvature aberration, on the other hand, through first insulating framework and second insulating framework respectively from the core top to the core bottom and make the first saddle with second saddle one -to -one, cooperate the multipole structure of the coil winding electric connection in turn and form, ensure that deflection magnetic field is symmetrical distribution, promote the magnetic field uniformity, break through the limitation of traditional electron gun single -time scanning plane. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate an embodiment consistent with the present utility model and, together with the description, serve to explain the principles of the utility model. Obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0029] Figure 1 The structure schematic diagram of the electron gun of adopting horn mouth multipole deflection core in the exemplary embodiment of the utility model is shown.

[0030] Figure 2 The structure schematic diagram of the multipole deflector in the exemplary embodiment of the utility model is shown.

[0031] Figure 3 The structure schematic diagram of the core in the exemplary embodiment of the utility model is shown.

[0032] Figure 4 The structure schematic diagram of the first insulating framework in the exemplary embodiment of the utility model is shown.

[0033] Figure 5 The structure schematic diagram of the second insulating framework in the exemplary embodiment of the utility model is shown.

[0034] Figure 6 The structure schematic diagram of the first wire card in the exemplary embodiment of the utility model is shown.

[0035] Figure 7 The structure schematic diagram of the second wire card in the exemplary embodiment of the utility model is shown.

[0036] Figure 8 The structure schematic diagram of the multipole deflector with ferrite magnetic ring in the exemplary embodiment of the utility model is shown.

[0037] 100, cathode assembly; 200, dynamic focuser; 300, erector; 400, focuser; 500, multipole deflector; 501, core; 502, convex wall; 503, first insulating framework; 5031, first annular portion; 5032, first saddle portion; 5033, first channel; 5034, first support plate; 504, second insulating framework; 5041, second annular portion; 5042, second saddle portion; 5043, second channel; 5044, second support plate; 505, coil winding; 506, first wire clamp; 5061, third annular portion; 5062, third saddle portion; 507, second wire clamp; 5071, fourth annular portion; 5072, fourth saddle portion; 508, ferrite magnetic ring; 600, electron beam. DETAILED DESCRIPTION

[0038] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example implementations to those skilled in the art. The described features, structures, or characteristics can be combined in one or more implementations.

[0039] In addition, the accompanying drawings are included to provide a further understanding of embodiments of the application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings:

[0040] An electron gun with a horn-shaped multipole deflection core is provided in the present example implementation, referring to FIG. 1, Figure 1 Figure 2 As shown, the electron gun with a horn-shaped multipole deflection core can include an electron-optical main part, which includes a cathode assembly 100, a dynamic focuser 200, an erector 300, a focuser 400, and a multipole deflector 500 arranged coaxially in sequence along the direction of electron beam propagation.

[0041] The multipole deflector 500 includes:

[0042] a core 501, which is cylindrical and horn-shaped with a top cross-section smaller than a bottom cross-section;

[0043] an insulating framework, which includes a first insulating framework 503 and a second insulating framework 504;

[0044] ​The first insulation skeleton 503 comprises a first annular portion 5031 and a plurality of first saddle portions 5032 distributed circumferentially along the inner wall of the first annular portion 5031 and extending axially downward along the first annular portion 5031, and the plurality of first saddle portions 5032 of the first insulation skeleton 503 protrude into the iron core 501 from the top of the iron core 501 to set the first annular portion 5031 on the top of the iron core 501;

[0045] The second insulation skeleton 504 comprises a second annular portion 5041 and a plurality of second saddle portions 5042 distributed circumferentially along the inner wall of the second annular portion 5041 and extending axially upward along the second annular portion 5041, and the plurality of second saddle portions 5042 of the second insulation skeleton 504 protrude into the iron core 501 from the bottom of the iron core 501 to set the second annular portion 5041 on the bottom of the iron core 501, and the plurality of second saddle portions 5042 correspond one-to-one to the plurality of first saddle portions 5032;

[0046] The coil winding 505, the plurality of coil windings 505 are respectively wound on the plurality of first saddle portions 5032 and the plurality of second saddle portions 5042 corresponding to the plurality of first saddle portions 5032 one-to-one, and the plurality of coil windings 505 surround the horn-shaped space of the electron beam 600 deflection, and are sequentially electrically connected to form a multi-pole structure.

[0047] It needs to be understood that when the electron gun is working, the electron beam 600 is emitted by the cathode assembly 100 in the electron optical main part, the electrons emitted by the cathode are accelerated to form a high-energy electron beam through the high-voltage electric field between the cathode and the anode, and the electron beam 600 is formed through the regulation of the dynamic focus 200, the eraser 300 and the focus 400, which is a high-energy, small-beam spot and stable electron beam 600. This part is prior art, and will not be described hereinafter. Subsequently, the electron beam 600 enters the multipole deflector 500, in which the multiple coil windings 505 surround the horn-shaped space for deflection of the electron beam 600 to generate a uniform deflection magnetic field. Since the coil windings 505 adopt a multipole structure, the deflection center of the electron beam 600 can be better matched with the ideal image point of the electron optical system, thereby greatly reducing the coma, field curvature and other aberrations. The electron beam 600 flies in the horn-shaped magnetic field throughout the entire process in the precisely controlled deflection magnetic field, thereby realizing high-efficiency, low-aberration and large-angle deflection. The multipole deflector 500 provides a longer effective deflection arm, so that the electron beam 600 can obtain a larger deflection angle when leaving the multipole deflector 500 without significantly increasing the physical distance from the outlet of the multipole deflector 500 to the processing platform. Under the premise of ensuring the beam spot quality, the single scanning range is expanded from 50mm*50mm to 200mm*200mm, with an area increase of 16 times. Without mechanical splicing, the processing of large-size workpieces can be realized, the splicing error is eliminated, and the production efficiency is greatly improved.

[0048] The electronic gun with the horn-mouth multipole deflection iron core provided by the embodiment of the utility model, on the one hand, the horn-shaped iron core 501 and the coil winding 505 wound on the first saddle part 5032 and the corresponding second saddle part 5042 jointly enclose the horn-shaped electron beam 600 deflection space, prolong the effective action path of the deflection magnetic field to the electron beam 600, provide the physical basis for the large-angle deflection of the electron beam 600, reduce the axial external astigmatism and field curvature aberration in the deflection process, on the other hand, the first insulating framework 503 and the second insulating framework 504 respectively extend into the iron core 501 from the top of the iron core 501 to the bottom of the iron core 501 and make the first saddle part 5032 and the second saddle part 5042 one-to-one corresponding, cooperate with the multipole structure formed by the coil winding 505 in turn electrically connected, ensure the symmetrical distribution of the deflection magnetic field, improve the uniformity of the magnetic field, and break through the limitation of the single scanning range of the traditional electron gun.

[0049] The above-mentioned electronic gun with the horn-mouth multipole deflection iron core in the example embodiment will be described in more detail below. Figures 1 to 8 The above-mentioned electronic gun with the horn-mouth multipole deflection iron core in the example embodiment will be described in more detail below.

[0050] It is to be understood that in the traditional electron gun design, due to the dual influence of electron gun precision requirements and deflector performance, its amplitude domain is limited in a very small area, and it can only print small precision parts. There are two ways to expand the amplitude: one is to continue to increase the working distance after the lens, but the long-range space charge effect will make the beam diverge and the brightness decrease; the second is to improve the field uniformity and scanning angle of the deflector itself. The latter is considered to be a better path without sacrificing beam density. As early as the 1960s, cathode ray tube (CRT) television receivers have achieved large-angle, microsecond-level fast scanning of ±45°, and the core is the horn-shaped deflection coil. The magnetic lines of force are uniformly mapped to the entire cone cavity through the axisymmetric conical pole piece. The electron beam is subjected to almost the same Lorentz force whether it is at the center or the edge, so that the raster distortion is more accurately controlled.

[0051] In the traditional cathode ray tube (CRT), the "saddle-ring" two-component deflection coil system is generally used. Among them, the row deflection coil is usually saddle-shaped, and the field deflection coil is ring-shaped, which are wound and superimposed. The magnetic field of this structure is mainly concentrated and established in the local area of the tube neck of the picture tube. When it is necessary to increase the deflection angle, in order to obtain a long enough deflection path, it is usually necessary to increase the length of the tube neck, but this will cause the device to be bulky and the power consumption to increase. More importantly, under large deflection angles, the leakage magnetic field of this structure will increase sharply, and the magnetic field uniformity will deteriorate rapidly, thereby introducing serious geometric distortion and aberration, which limits its application in high-end precision scanning devices, such as in electron beam 3D printing.

[0052] By learning from the mature technology of cathode ray tube (CRT) television, the deflection coil adopts a horn-shaped shape, which can generate a very uniform deflection magnetic field, realizing fast, large-angle, low-distortion scanning of the electron beam on the fluorescent screen. However, the CRT technology is mainly applied to the display field of low energy and large beam spot, and its design idea has not been directly transplanted to high-end electron optical devices requiring high precision and small beam spot. Therefore, the utility model learns from the CRT "horn mouth uniform field" concept, and solves the problems of saturation, thermal drift and high-order harmonic through new materials, new pole piece curves and new coil topologies, and breaks through large-size, nanoscale electron beam scanning. The electron gun with a horn-shaped multi-pole deflection core of the utility model realizes ±20° low-aberration scanning under the condition of 60-150keV, 100nm beam spot, and expands the single amplitude from the traditional 50mm to 240mm, providing a core hardware foundation for meter-level metal 3D printing, large-size wafer direct writing and high-depth welding.

[0053] In one embodiment, as Figure 3 , Figure 4 , Figure 5As shown, the inner wall of the core 501 is circumferentially distributed with a plurality of raised walls 502, each of which extends from the top of the core 501 to the bottom of the core 501; the bottom of each first saddle portion 5032 is provided with a first channel 5033, and the plurality of first saddle portions 5032 of the first insulation framework 503 extend into the core 501 from the top of the core 501 and are respectively clamped to the top of the plurality of raised walls 502 through the plurality of first channels 5033 to set the first annular portion 5031 at the top of the core 501; the top of each second saddle portion 5042 is provided with a second channel 5043, and the plurality of second saddle portions 5042 of the second insulation framework 504 extend into the core 501 from the bottom of the core 501 and are respectively clamped to the bottom of the plurality of raised walls 502 through the plurality of second channels 5043 to set the second annular portion 5041 at the bottom of the core 501. First support plates 5034 are arranged between adjacent first saddle portions 5032 in the plurality of first saddle portions 5032, and second support plates 5044 are arranged between adjacent second saddle portions 5042 in the plurality of second saddle portions 5042. It should be understood that the plurality of first saddle portions 5032, the plurality of second saddle portions 5042, and the plurality of raised walls 502 are uniformly distributed to ensure that the circumferential positions of the first saddle portions 5032 and the second saddle portions 5042 in the core 501 are aligned, thereby avoiding winding offset of the coil winding 505 due to mispositioning of the first saddle portions 5032 and the second saddle portions 5042 and ensuring the symmetry of the multi-pole structure. The coil winding 505 is annularly wound during the winding process by passing from the first saddle portion 5032 along the profile of one side of the raised wall 502, through the second saddle portion 5042 along the profile of the other side of the raised wall 502, to the first saddle portion 5032, the core 501 is cylindrical and has a horn shape with a top cross section smaller than a bottom cross section, the inner wall of the core 501 is circumferentially distributed with a plurality of raised walls 502, each of which extends from the top end of the inner wall of the core 501 to the bottom end of the inner wall of the core 501, and has a consistent raised height to form a raised wall 502 with an arc, and the plurality of coil windings 505 are respectively annularly wound during the winding process by passing from the first saddle portion 5032 along the profile of one side of the raised wall 502 with an arc, through the second saddle portion 5042 along the profile of the other side of the raised wall 502 with an arc, to the first saddle portion 5032, so that the arc of each coil winding 505 is consistent with the horn shape of the core 501, the plurality of coil windings 505 enclose a horn-shaped space for deflection of the electron beam 600, the spacing between adjacent coil windings 505 is uniform, thereby avoiding magnetic field distribution distortion due to winding offset and ensuring that the electron beam 600 is subjected to a uniform magnetic field during deflection, providing structural support for large-angle deflection of ±20° or more and large-format scanning of 200mm×200mm or more, and reducing axial astigmatism, field curvature, and other aberrations.

[0054] It is also important to understand that the first support plate 5034 and the second support plate 5044 fix the first saddle 5032 and the second saddle 5042 circumferentially, which avoids local stress on the insulation layer caused by slight deformation of the first saddle 5032 and the second saddle 5042 when the coil winding 505 is wound or working, and reduces the risk of wear on the winding insulation layer.

[0055] In one embodiment, such as Figure 2 , 6 As shown in Figure 7, the multi-pole deflector 500 further includes a wire clamp, which includes a first wire clamp 506 and a second wire clamp 507. The first wire clamp 506 includes a third annular portion 5061 and a plurality of third saddle portions 5062 distributed circumferentially along the third annular portion 5061 and extending axially downward along the third annular portion 5061. The plurality of third saddle portions 5062 extend from the top of the iron core 501 and are respectively inserted between the plurality of protruding walls 502. The outer wall of the third annular portion 5061 is connected to the core 501. The coil winding 505 of the first saddle portion 5032 is attached; the second wire clamp 507 includes a fourth annular portion 5071 and a plurality of fourth saddle portions 5072 distributed circumferentially along the fourth annular portion 5071 and extending axially upward along the fourth annular portion 5071. The plurality of fourth saddle portions 5072 extend from the bottom of the iron core 501 and are respectively inserted between the plurality of protruding walls 502. The outer wall of the fourth annular portion 5071 is attached to the coil winding 505 wound on the second saddle portion 5042. It should be understood that the third saddle portion 5062 of the first wire clip 506 and the fourth saddle portion 5072 of the second wire clip 507 are inserted between the protruding wall 502 from the upper and lower directions, respectively. On the one hand, they are used to fix the wire clip, and on the other hand, they are used to prevent the coil from expanding or shifting in the circumferential direction. The third annular portion 5061 and the fourth annular portion 5071 are respectively attached to the coil winding 505, which radially reinforces the coil winding 505 wound on the first saddle portion 5032 and the coil winding 505 wound on the second saddle portion 5042 to prevent them from detaching.

[0056] In one embodiment, the number of the plurality of first saddles 5032 is 2N, where N is an integer greater than or equal to 4 and less than or equal to 12. The number of second saddles 5042 is the same as the number of first saddles 5032, and the number of protruding walls 502 is the same as the number of first saddles 5032. It should be understood that the matching of the number of first saddles 5032, second saddles 5042, and protruding walls 502 enables the coil winding 505 to form a multi-pole structure with at least eight poles. By passing reverse current through adjacent coil windings 505, N pole pairs are formed, where 12 ≥ N ≥ 4. The magnetic fields between the pole pairs superimpose to cancel out higher harmonics.

[0057] In one specific embodiment, the multi-pole structure is a 20-pole structure. The 20-pole structure can more effectively suppress specific high-order harmonics, thereby smoothing the magnetic field distribution in the edge region, reducing "saddle-valley" fluctuations, and improving the uniformity of the magnetic field. In actual measurements, the magnetic field inhomogeneity of the icosahedral structure within a scanning domain with an inlet diameter of 40 mm can be controlled to below 1.2%. If the inhomogeneity index is relaxed to 3%, the inlet diameter of the scanning domain can be increased from 40 mm to 48 mm. At this time, the scanning area increases from 200 mm × 200 mm to 240 mm × 240 mm without increasing the working distance of the electron beam 600. The height difference between the "saddle-valley" of the edge field decreases from 0.9 mT to 0.55 mT; the beam spot ellipticity decreases from 1.06 to 1.02; the electron beam 600 maintains good beam spot quality even when deflected at large angles; the melt channel width value decreases by another 0.4%; and the surface roughness of the Ti-6Al-4V sample with a layer thickness of 50 µm decreases from 8.2 µm to 6.9 µm. The uniform magnetic field of the icosahedral structure ensures that the electron beam 600 deflects consistently throughout the entire scanning area. The 20-pole structure improves the surface quality of parts by enhancing beam spot roundness and scanning consistency, meeting the stringent requirements of high-end manufacturing for precision and surface finish, and satisfying the high-precision machining needs of large-sized components such as aerospace titanium alloy integral frames and rocket engine combustion chambers.

[0058] In one embodiment, such as Figure 8 As shown, the multi-pole deflector 500 also includes a ferrite magnetic ring 508, which is horn-shaped. The ferrite magnetic ring 508 is sleeved on the outer wall of the iron core 501, and there is a gap of 0.5mm to 1mm between the inner wall of the ferrite magnetic ring 508 and the outer wall of the iron core 501. The expansion angle of the horn shape of the ferrite magnetic ring 508 is the same as the expansion angle of the horn shape of the iron core 501. It is important to understand that the high permeability of the ferrite magnetic ring 508 provides a low-resistance closed-loop path for the magnetic field lines, allowing the main magnetic flux generated by the coil winding 505 to pass perpendicularly through the electron beam 600 channel, reducing magnetic flux leakage and increasing magnetic field strength. The insulation gap between the magnetic ring and the iron core 501 is 0.5mm to 1mm, which avoids magnetic saturation caused by direct contact between the magnetic ring and the iron core 501, and ensures the continuity of the magnetic circuit. This increases the deflection magnetic field strength generated by the coil under the same operating current, providing sufficient magnetic field driving force for the electron beam 600 to deflect at large angles. Flattening the magnetic equipotential surface extends the uniform magnetic field area towards the exit direction, covering a larger deflection range of the electron beam 600.

[0059] In one embodiment, the multipole deflector 500 further comprises a housing (not shown in the figure), which is trumpet-shaped, the trumpet-shaped expansion angle of the housing is the same as that of the ferrite magnetic ring 508, the housing is sleeved on the outer wall of the ferrite magnetic ring 508, and a water-cooling channel is arranged on the housing. It should be understood that the water-cooling channel refers to a closed path for circulating cooling liquid arranged on the wall of the housing. The channel can be arranged in various shapes and layouts, such as spiral, serpentine or grid, to maximize the contact area between the cooling liquid and the outer housing, thereby improving the heat dissipation efficiency. The water-cooling channel is arranged on the housing, so that the heat generated by the coil winding 505 during operation can be conducted to the housing and absorbed by the cooling liquid in the water-cooling channel, and the cooling liquid circulates in the channel to take away the absorbed heat from the coil winding 505 area, thereby effectively reducing the working temperature of the coil winding 505. The temperature stability of the coil under long-time high-load operation is ensured, the performance degradation and service life shortening caused by overheating of the coil are avoided, and the deflection accuracy and stability of the electron gun under long-time working condition are also ensured.

[0060] In one embodiment, the trumpet-shaped expansion angle is 10°±3°. It should be understood that the trumpet-shaped expansion angle is the angle between the trumpet-shaped conical surface and the axial direction of the electron gun.

[0061] In one specific embodiment, the trumpet-shaped inlet diameter of 40mm-55mm matches the outlet of the focusing system, and the trumpet-shaped outlet diameter of 60mm-80mm matches the typical powder bed with a scanning area of 200mm×200mm. The 10°±3° expansion angle prolongs the effective flight path of the electron beam 600 in the deflection area by 30% compared with the 5° expansion angle, and cooperates with the 100mm axial length of the core 501 to stably realize ±20° large-angle deflection at a working distance of 300mm-450mm, without the need to lengthen the working distance to cover a scanning area of more than 200mm×200mm.

[0062] In one embodiment, the coil winding 505 includes a first coil group for generating a magnetic field in the X direction and a second coil group for generating a magnetic field in the Y direction. It should be understood that the wire specification uses high-temperature resistant enameled wire with a diameter of 0.6-0.8 mm, a heat-resistant temperature of 180°C, and is suitable for the high-temperature environment in the printing cabin; the winding process uses combined winding, with 1-2 coil groups per pole, a number of turns of 16-52 turns, and a comprehensive resistance value of 0.8-1.2 Ω; the rated working current is 5 A, and the continuous working current is 3 A; it should also be understood that the first coil group refers to a group of coil windings 505 that can generate a magnetic field that deflects the electron beam 600 in the X direction, which will form a magnetic field gradient in the X direction when current passes through, thereby deflecting the electron beam 600; the second coil group refers to a group of coil windings 505 that can generate a magnetic field that deflects the electron beam 600 in the Y direction, which has a similar working principle to the first coil group, but the direction of the generated magnetic field is perpendicular to the X direction, and is used to control the deflection of the electron beam 600 in the Y direction. By controlling the first coil group and the second coil group, the movement trajectory of the electron beam 600 can be accurately controlled, thereby improving the performance of the electron gun. By independently controlling the current size and direction in the first coil group and the second coil group, the magnetic field strength in the X direction and the Y direction can be accurately adjusted, thereby realizing arbitrary trajectory control of the electron beam 600 in a two-dimensional plane. Compared with the traditional deflection coil, this control method has higher flexibility and precision, and can meet the needs of high-resolution display and precision electron beam processing fields.

[0063] It should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. in the above description indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0064] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified.

[0065] In the embodiments of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be interpreted in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication between two elements or the interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0066] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or can include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "on the surface of" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0067] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application.

[0068] Other embodiments of the present application will be apparent to those skilled in the art upon consideration of the specification and practice of the present application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application following the general principles thereof and including the non-disclosed common knowledge or conventional technical means in the technical field of the present application. The specification and examples are only considered as exemplary, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. An electron gun employing a horn mouth multi-pole deflection core, comprising an electron optical main part including, in the order along the electron beam propagation direction, a cathode assembly, a dynamic focuser, an erector, a focuser, and a multi-pole deflector, characterized in that, The multi-pole deflector comprises: an iron core, which is cylindrical and trumpet-shaped with a top cross section smaller than a bottom cross section; an insulating framework, which comprises a first insulating framework and a second insulating framework; the first insulating framework comprises a first annular portion and a plurality of first saddle portions distributed circumferentially along an inner wall of the first annular portion and extending axially downward along the first annular portion, and the plurality of first saddle portions extend into the iron core from a top of the iron core to position the first annular portion at the top of the iron core; the second insulating framework comprises a second annular portion and a plurality of second saddle portions distributed circumferentially along an inner wall of the second annular portion and extending axially upward along the second annular portion, and the plurality of second saddle portions extend into the iron core from a bottom of the iron core to position the second annular portion at the bottom of the iron core, and the plurality of second saddle portions correspond to the plurality of first saddle portions one by one; a plurality of coil windings, which are wound on the plurality of first saddle portions and the plurality of second saddle portions corresponding to the plurality of first saddle portions one by one, respectively, and are sequentially electrically connected to form a multi-pole structure.

2. The electron gun employing a multi-pole deflection core with a horn aperture according to claim 1, characterized in that, The inner wall of the iron core is circumferentially provided with a plurality of protruding walls, and each protruding wall extends from a top of the iron core to a bottom of the iron core; a bottom of each first saddle portion is provided with a first groove, and the plurality of first saddle portions of the first insulating framework extend into the iron core from the top of the iron core, and are clamped on top of the plurality of protruding walls through the plurality of first grooves to position the first annular portion at the top of the iron core; a top of each second saddle portion is provided with a second groove, and the plurality of second saddle portions of the second insulating framework extend into the iron core from the bottom of the iron core, and are clamped on bottom of the plurality of protruding walls through the plurality of second grooves to position the second annular portion at the bottom of the iron core.

3. The electron gun employing a multi-pole deflection core with a horn mouth according to claim 2, characterized in that, The multi-pole deflector further comprises wire clamps, which comprise first wire clamps and second wire clamps; the first wire clamps comprise a third annular portion and a plurality of third saddle portions distributed circumferentially along the third annular portion and extending axially downward along the third annular portion, and the plurality of third saddle portions extend into the iron core from the top of the iron core and are inserted between the plurality of protruding walls, and an outer wall of the third annular portion is in contact with the coil windings wound on the first saddle portions; the second wire clamps comprise a fourth annular portion and a plurality of fourth saddle portions distributed circumferentially along the fourth annular portion and extending axially upward along the fourth annular portion, and the plurality of fourth saddle portions extend into the iron core from the bottom of the iron core and are inserted between the plurality of protruding walls, and an outer wall of the fourth annular portion is in contact with the coil windings wound on the second saddle portions.

4. The electron gun employing a multi-pole deflection core with a horn mouth according to claim 2, characterized in that, The number of the plurality of first saddle portions is 2N, where N is an integer greater than or equal to 4 and less than or equal to 12, the number of the second saddle portions is the same as that of the first saddle portions, and the number of the protruding walls is the same as that of the first saddle portions.

5. The electron gun employing a multi-pole deflection core with a horn aperture according to claim 1, wherein First support plates are arranged between adjacent first saddle portions in the plurality of first saddle portions, and second support plates are arranged between adjacent second saddle portions in the plurality of second saddle portions.

6. The electron gun employing a multi-pole deflection core with a horn aperture according to claim 1, wherein The multi-pole deflector further comprises a ferrite magnetic ring, which is trumpet-shaped, sleeved on the outer wall of the iron core, and has a gap of 0.5-1 mm between the inner wall of the ferrite magnetic ring and the outer wall of the iron core, and the trumpet-shaped expansion angle of the ferrite magnetic ring is the same as that of the iron core.

7. The electron gun employing a multi-pole deflection core with a horn mouth according to claim 6, characterized in that, The multi-pole deflector further comprises a shell, which is trumpet-shaped, has the same trumpet-shaped expansion angle as that of the ferrite magnetic ring, is sleeved on the outer wall of the ferrite magnetic ring, and is provided with a water cooling channel.

8. The electron gun employing a multi-pole deflection core with a horn mouth according to claim 1, characterized in that, The trumpet-shaped expansion angle is 10°±3°.

9. The electron gun employing a multi-pole deflection core with a horn aperture according to claim 1, wherein, The multi-pole structure is a twenty-pole structure.

10. The electron gun employing a multi-pole deflection core with a horn aperture according to claim 1, wherein, The coil winding comprises a first coil group for generating a magnetic field in the X direction and a second coil group for generating a magnetic field in the Y direction.

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