Large-object-plane wide-beam low-energy carbon nanotube cold cathode electron gun

Abstract

The invention relates to the technical field of vacuum electronics, in particular to a large-object-plane wide-beam low-energy carbon nanotube cold cathode electron gun, which comprises a cover plate, a shell, a base, a focusing electrode, a large-object-plane cathode assembly and an electrode column, and is characterized in that the cover plate is fixed at the top end of the shell, and the bottom end of the shell is fixed on the base; the focusing electrode is arranged in the shell and comprises a first focusing electrode, a speed reducing electrode and a second focusing electrode; the large object plane cathode assembly is arranged in the shell and is fixedly connected with the first focusing electrode through a ceramic insulating spacer and a connecting piece insulating bush; and the electrode column is fixed on the base through the connecting piece insulating bush. According to the invention, a five-electrode structure comprising a large-object-surface carbon nanotube cathode, a grid electrode, a first focusing electrode, a deceleration electrode and a second focusing electrode is adopted, and a cathode-grid structure composed of the large-area carbon nanotube cathode and the grid electrode can emit stable and high-strength electron beams.

Description

Technical Field

[0001] The present application relates to the technical field of vacuum electronics, and in particular to a large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun. Background Art

[0002] Large-object-area wide-beam cold cathode electron guns are widely used in surface treatment, material processing, microelectronics manufacturing, electron microscopy, ultra-low-energy wide-beam ion sources and other fields. However, they still have significant defects in key performance aspects such as electron beam energy, energy distribution, beam uniformity and beam intensity, which limits their further application in high-precision and large-area processing.

[0003] At present, the large-object-area wide-beam cold cathode electron gun mainly relies on the field emission effect to generate the electron beam. The energy of the emitted electron beam is relatively high, usually above 100 eV, and this emission mechanism makes the energy distribution of the electron beam relatively wide. Due to the non-uniformity of the electron energy of the field emission effect, it is difficult to achieve precise control in the low energy range (such as tens of eV to hundreds of eV), resulting in a large energy divergence of the electron beam, which affects the energy control requirements in the precision machining process. In addition, since the cold cathode emission is concentrated at the local emission point, the uniformity of the beam is poor, especially in the large-object-area wide-beam application, the electron density at the center and edge of the beam spot is significantly different, resulting in uneven electron beam bombardment intensity on the processing surface, which ultimately affects the process effect.

[0004] At the same time, insufficient and fluctuating beam intensity is also one of the challenges faced by cold cathode electron guns. The field emission effect is extremely sensitive to working environments such as electric field strength and vacuum, which makes it difficult to maintain stable beam intensity and low electron emission efficiency. Especially in applications with high current density requirements, the beam intensity often does not meet process requirements. These defects limit the performance and reliability of cold cathode electron guns in some high-precision, high-power applications, hindering their use in processes that require long-term continuous operation. Summary of the invention

[0005] The present application provides a large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun, which has low electron beam energy, high beam current intensity, and small electron beam divergence angle, and can meet the requirements of high-precision and large-area applications.

[0006] In order to achieve the above-mentioned purpose, the present application provides a large-object-area wide-beam low-energy carbon nanotube cold cathode electron gun, comprising a cover plate, an outer shell, a base, a focusing electrode, a large-object-area cathode assembly and an electrode column, wherein: the cover plate is fixed to the top end of the outer shell, and the bottom end of the outer shell is fixed to the base; the focusing electrode is arranged inside the outer shell, and comprises a first focusing electrode, a deceleration electrode and a second focusing electrode, the second focusing electrode is fixed to the bottom of the cover plate through a ceramic insulating gasket and a connector insulating bushing, and the deceleration electrode is fixedly connected to the second focusing electrode through a ceramic insulating gasket and a connector insulating bushing; the first focusing electrode is fixedly connected to the deceleration electrode through a ceramic insulating gasket and a connector insulating bushing; the large-object-area cathode assembly is arranged inside the outer shell, and is fixedly connected to the first focusing electrode through a ceramic insulating gasket and a connector insulating bushing; the electrode column is fixed to the base through a connector insulating bushing, and one end is exposed to the outside of the base.

[0007] Furthermore, the large object surface cathode assembly includes a cathode, a gate, a cathode ceramic seat, a first fixing part, a second fixing part and a gate pressure ring, wherein: the two sides of the cathode are fixed to the cathode ceramic seat by threaded connection; the first fixing part and the second fixing part are fixed to the cathode ceramic seat by threaded connection in turn; the gate is arranged above the cathode and fixed to the second fixing part by a gate pressure ring.

[0008] Furthermore, the cathode is a large-area carbon nanotube cathode with a diameter of 30 mm.

[0009] Furthermore, the distance between the cathode and the gate is 200 μm.

[0010] Furthermore, the focusing electrode is a conical cylinder structure, the taper of the first focusing electrode is 3°, and the taper of the second focusing electrode is 14°.

[0011] Furthermore, the lengths of the first focusing pole, the deceleration pole and the second focusing pole are equal to the diameter of the cathode, and the inner diameter of the deceleration pole is 1.5 times the diameter of the cathode.

[0012] Furthermore, the cathode, the grid, the first focusing electrode, the deceleration electrode and the second focusing electrode are connected to respective power sources through electrode columns, wherein: the outer shell is grounded; the cathode is connected to a negative voltage of 60-70V; the grid is connected to a positive voltage of 1000V; the first focusing electrode is connected to a positive voltage of 1200-1300V; the deceleration electrode is connected to a positive voltage of 400V; and the second focusing electrode is connected to a positive voltage of 10V.

[0013] Furthermore, the electron beam divergence angle is less than 10°, the electron beam waist diameter is 30 mm, and the electron beam energy is a single 75 eV.

[0014] The present application provides a large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun, which has the following beneficial effects:

[0015] The present application adopts a five-electrode structure of a large-object-surface carbon nanotube cathode, a grid, a first focusing electrode, a deceleration electrode, and a second focusing electrode. The cathode-grid structure composed of a large-area carbon nanotube cathode and a grid can emit a stable, high-intensity electron beam. The electrostatic lens system composed of the first focusing electrode, the deceleration electrode, and the second focusing electrode can effectively confine electrons, so that the electron beam has the characteristics of high beam intensity, low and single electron beam energy, small divergence angle, wide beam, and uniform distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0017] Figure 1 It is a schematic diagram of the internal structure of a large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun provided according to an embodiment of the present application;

[0018] Figure 2 It is a schematic diagram of a large-object-surface wide-beam low-energy carbon nanotube cold cathode electron gun provided in an embodiment of the present application from one angle;

[0019] Figure 3 is a schematic diagram from another angle of the large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun provided in an embodiment of the present application;

[0020] Figure 4 is a schematic diagram of a large object surface cathode assembly provided in an embodiment of the present application;

[0021] In the figure: 1-base, 2-housing, 3-cover plate, 4-ceramic insulating gasket, 5-second focusing electrode, 6-deceleration electrode, 7-first focusing electrode, 8-gate pressure ring, 9-second fixing piece, 10-first fixing piece, 11-cathode ceramic seat, 12-cathode, 13-gate, 14-connecting piece insulating bushing, 15-electrode column. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0025] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0026] In addition, the term "plurality" shall mean two or more.

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] like Figure 1-3As shown, the present application provides a large object surface wide beam low energy carbon nanotube cold cathode electron gun, including a cover plate 3, a shell 2, a base 1, a focusing electrode, a large object surface cathode assembly and an electrode column 15, wherein: the cover plate 3 is fixed to the top end of the shell 2, and the bottom end of the shell 2 is fixed to the base 1; the focusing electrode is arranged inside the shell 2, including a first focusing electrode 7, a deceleration electrode 6 and a second focusing electrode 5, the second focusing electrode 5 is fixed below the cover plate 3 through a ceramic insulating gasket 4 and a connector insulating bushing 14, the deceleration electrode 6 is fixedly connected to the second focusing electrode 5 through a ceramic insulating gasket 4 and a connector insulating bushing 14; the first focusing electrode 7 is fixedly connected to the deceleration electrode 6 through a ceramic insulating gasket 4 and a connector insulating bushing 14; the large object surface cathode assembly is arranged inside the shell 2, and is fixedly connected to the first focusing electrode 7 through a ceramic insulating gasket 4 and a connector insulating bushing 14; the electrode column 15 is fixed to the base 1 through the connector insulating bushing 14, and one end is exposed to the outside of the base 1.

[0029] Specifically, the large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun provided in the embodiment of the present application is based on a large-area carbon nanotube cathode. It improves the electron beam energy control accuracy, improves the beam uniformity and enhances the beam intensity by optimizing the electric field design and improving the beam stability, thereby meeting the needs of high-precision and large-area applications. Among them, the cover plate 3, the shell 2 and the base 1 constitute the overall gun body structure of the electron gun, the cover plate 3 is fixed to the top of the shell 2 through a threaded hole, and the bottom of the shell 2 is fixed to the base 1 through a threaded hole; the large object surface cathode assembly is arranged inside the shell 2 for emitting an electron beam; the focusing electrode is arranged at the front end of the large object surface cathode assembly for focusing and constraining the electron beam to ensure that a stable and high-intensity electron beam current can be emitted; the distance between the first focusing electrode 7 and the deceleration electrode 6, and the deceleration electrode 6 and the second focusing electrode 5 is preferably controlled by a ceramic insulating gasket 4, and the distance is 1 mm; the ceramic insulating gasket 4 and the connecting piece insulating bushing 14 are used for insulation during the connection process; the electrode column 15 is arranged on the base 1, and passes through the base 1 as a whole, one end is connected to the power supply, and the other end is connected to the cathode assembly and the focusing electrode; the overall structure of the assembled electron gun is fixedly docked with a base flange.

[0030] Further, such as Figure 4 The large-surface cathode assembly includes a cathode 12, a grid 13, a cathode ceramic seat 11, a first fixing member 10, a second fixing member 9 and a grid pressure ring 8, wherein: both sides of the cathode 12 are fixed to the cathode ceramic seat 11 by threaded connection; the first fixing member 10 and the second fixing member 9 are fixed to the cathode ceramic seat 11 by threaded connection in turn; the grid 13 is arranged above the cathode 12 and is fixed to the second fixing member 9 by the grid pressure ring 8. The cathode 12 is arranged on the cathode ceramic seat 11 by bolts and nuts; the grid 13 is arranged above the cathode 12 by the grid pressure ring 8, and is fixedly isolated from the cathode 12 by the first fixing member 10 and the second fixing member 9.

[0031] Furthermore, the cathode 12 is a large-area carbon nanotube cathode with a diameter of 30 mm.

[0032] Furthermore, the distance between the cathode 12 and the gate 13 is 200 μm.

[0033] Specifically, in the embodiment of the present application, the material of the cathode 12 is preferably large-area carbon nanotubes, the diameter is preferably 30 mm, and the distance between the cathode 12 and the gate 13 is preferably 200 μm.

[0034] Furthermore, the focusing electrode is a conical cylinder structure, the taper of the first focusing electrode 7 is 3°, and the taper of the second focusing electrode 5 is 14°. The focusing electrode adopts a simple conical cylinder structure, which has a simple structure, convenient installation, and clear principle. The first focusing electrode 7 and the second focusing electrode 5 are both conical structures, and their tapers are 3° and 14° respectively.

[0035] Furthermore, the lengths of the first focusing electrode 7 , the deceleration electrode 6 and the second focusing electrode 5 are equal to the diameter of the cathode 12 , and the inner diameter of the deceleration electrode 6 is 1.5 times the diameter of the cathode 12 .

[0036] Furthermore, the cathode 12, the grid 13, the first focusing electrode 7, the deceleration electrode 6 and the second focusing electrode 5 are connected to respective power sources through the electrode column 15, wherein: the outer shell 2 is grounded; the cathode 12 is connected to a negative voltage of 60-70V; the grid 13 is connected to a positive voltage of 1000V; the first focusing electrode 7 is connected to a positive voltage of 1200-1300V; the deceleration electrode 6 is connected to a positive voltage of 400V; and the second focusing electrode 5 is connected to a positive voltage of 10V.

[0037] Furthermore, the electron beam divergence angle is less than 10°, the electron beam waist diameter is 30 mm, and the electron beam energy is a single 75 eV.

[0038] Specifically, in the embodiment of the present application, after the overall structure is assembled, according to the actual situation, the CST particle studio is used to perform simulation optimization, and the electron gun is simulated and modeled using the CST particle studio, and the size of the first focusing electrode 7, the deceleration electrode 6, and the second focusing electrode 5, the spacing between the cathode 12 and the grid 13, and the voltage of each electrode are changed, so as to obtain an electron gun model that meets the simulation requirements; the electron gun simulation performance is: the electron beam divergence angle is less than 10°, the electron beam waist diameter is 30 mm, and the electron beam energy is a single 75eV. The electron beam emitted by the embodiment of the present application has the advantages of high flow intensity, single beam energy, low energy, large beam spot size, small divergence angle, and uniform spatial distribution, and can be widely used in ultra-low energy wide beam ion sources.

[0039] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A large-surface, wide-beam, low-energy carbon nanotube cold cathode electron gun, characterized in that: It includes a cover plate, a housing, a base, a focusing electrode, a large object surface cathode assembly and an electrode column, wherein: The cover plate is fixed to the top end of the shell, and the bottom end of the shell is fixed to the base; The focusing electrode is arranged inside the housing, and includes a first focusing electrode, a deceleration electrode, and a second focusing electrode. The second focusing electrode is fixed below the cover plate through a ceramic insulating gasket and a connector insulating bushing, and the deceleration electrode is fixedly connected to the second focusing electrode through a ceramic insulating gasket and a connector insulating bushing; the first focusing electrode is fixedly connected to the deceleration electrode through a ceramic insulating gasket and a connector insulating bushing; The large object surface cathode assembly is arranged inside the housing and is fixedly connected to the first focusing electrode through a ceramic insulating gasket and a connector insulating bushing; The electrode column is fixed on the base through a connector insulating bushing, and one end is exposed outside the base.

2. The large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun according to claim 1, characterized in that: The large object surface cathode assembly comprises a cathode, a grid, a cathode ceramic seat, a first fixing member, a second fixing member and a grid pressure ring, wherein: The two sides of the cathode are fixed on the cathode ceramic seat by threaded connection; The first fixing member and the second fixing member are fixed to the cathode ceramic seat in sequence through threaded connection; The grid is arranged above the cathode and is fixed on the second fixing member via a grid pressure ring.

3. The large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun according to claim 2, characterized in that: The cathode is a large-area carbon nanotube cathode with a diameter of 30 mm.

4. The large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun according to claim 3, characterized in that: The distance between the cathode and the gate is 200 μm.

5. The large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun according to claim 4, characterized in that: The focusing electrode is a conical cylinder structure, the taper of the first focusing electrode is 3°, and the taper of the second focusing electrode is 14°.

6. The large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun according to claim 5, characterized in that: The lengths of the first focusing pole, the deceleration pole and the second focusing pole are equal to the diameter of the cathode, and the inner diameter of the deceleration pole is 1.5 times the diameter of the cathode.

7. The large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun according to claim 6, characterized in that: The cathode, the grid, the first focusing electrode, the deceleration electrode and the second focusing electrode are connected to respective power supplies through the electrode column, wherein: The housing is grounded; The cathode is connected to a negative voltage of 60-70V; The gate is connected to a positive voltage of 1000V; The first focusing electrode is connected to a positive voltage of 1200-1300V; The deceleration pole is connected to a positive voltage of 400V; The second focusing electrode is connected to a positive voltage of 10V.

8. The large-object-area, wide-beam, low-energy carbon nanotube cold cathode electron gun according to claim 7, characterized in that: The electron beam divergence angle is less than 10°, the electron beam waist diameter is 30 mm, and the electron beam energy is a single 75eV.

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