CN108231527B

CN108231527B - Uniform projection type electronic optical structure

Info

Publication number: CN108231527B
Application number: CN201810055508.XA
Authority: CN
Inventors: 赵健; 夏忠平; 朱滨
Original assignee: Shanghai Jiyouwei Optoelectronics Technology Co ltd
Current assignee: Shanghai Jiyouwei Optoelectronics Technology Co ltd
Priority date: 2018-01-19
Filing date: 2018-01-19
Publication date: 2022-06-14
Anticipated expiration: 2038-01-19
Also published as: CN108231527A

Abstract

The invention discloses a uniform projection type electron optical structure, comprising: a cathode region, a beam forming region, an electron gun exit region; a cathode is arranged in the cathode region and projects electrons to form a cathode emission surface; the electrons are emitted from the cathode emission surface through the beam forming area and the electron gun outlet area to finally form a projection area; the beam forming area comprises at least two beam forming areas, each beam forming area is of a metal cylinder structure, and the potential of each metal cylinder is independently adjustable and is used for controlling the electron beam form in the area; the beam forming area forms a primary inverted real image on the cathode emission surface; the projection area is a secondary inverted real image of the cathode emission surface, and finally the electrons are uniformly projected. Compared with the prior art, the cathode secondary inverted real image is projected to a required area by utilizing the high-voltage electric field for over-focusing without arranging a metal grid, and the uniformity of the electron beam of the projected area is ensured through an optimized structure.

Description

Uniform projection type electronic optical structure

Technical Field

The present invention relates to an electro-optical structure, and more particularly, to a uniform projection type electro-optical structure.

Background

The traditional projection type electron optical structure usually focuses electron beams for use, but electron beams uniformly projected to a certain area are needed in application fields of electron beam irradiation modification, irradiation aging, excitation illumination and the like. In the prior art, a uniform projection type electronic optical structure exists, but a metal grid mesh is generally required to be used for shielding the focusing effect of a high-voltage electric field. The disadvantages of this construction are as follows:

(1) the grid can intercept electrons, wasting part of electron beam current;

(2) the electrons intercepted by the grid mesh generate heat, so that the grid mesh is deformed;

(3) the high-quality grid mesh curved surface is not easy to process, and the projection uniformity is influenced;

(4) the grid mesh pores influence the projection uniformity, and the projection area is actually a virtual image of the grid mesh pores, so that a large number of point-like strong beam areas are caused;

(5) the size of the projection area is not easy to adjust, and the size of the electron beam is not easy to adjust.

Disclosure of Invention

In order to solve the defects in the prior art, the application provides an even projection type electron optical structure, wherein a metal grid mesh is not arranged, a high-voltage electric field is used for over-focusing, a secondary inverted real image of a cathode is projected to a required area, the electron emission uniformity of the cathode is ensured through an optimized structure, and the electron beam uniformity of the projection area is further ensured. The method is realized by the following technical scheme:

the uniformly projecting electron-optical structure comprises: a cathode region, a beam forming region, an electron gun exit region; a cathode is arranged in the cathode region and projects electrons to form a cathode emission surface; the electrons are emitted from the cathode emission surface through the beam forming area and the electron gun outlet area to finally form a projection area; the beam forming area comprises at least two beam forming areas, each beam forming area is of a metal cylinder structure, and the potential of each metal cylinder is independently adjustable and is used for controlling the electron beam form in the area; the beam forming area forms a primary inverted real image on the cathode emission surface; and the projection area is a secondary inverted real image of the cathode emission surface, and finally the electrons are uniformly projected.

Further, the cathode is flush with or protrudes from an end of the cathode region.

Further, when the cathode protrudes from the end of the cathode region, the protruding distance is within 0.05 mm.

Further, the interval between each beamlet-forming region is 0.5 ± 0.01 mm.

Further, the cathode is a thermal emission cathode or a field emission cathode.

Further, the beam size of the projected electrons changes with the change of the cathode potential.

Furthermore, the electron gun outlet region extends into one of the adjacent beamlet forming regions by a distance of 0.25-0.5 mm.

Further, the beam forming region includes three beamlet forming regions G2, G3, G4, wherein beamlet forming region G2 is the beamlet forming region closest to the cathode region, and beamlet forming regions G3 and G4 have the same tube diameter.

The invention has the following advantages:

(1) no metal grid mesh exists, so that electrons cannot be intercepted;

(2) the electron beam current and the projection area can be conveniently adjusted within a certain range;

(3) the uniformity of electron beam current in the projection area is good;

(4) the electron beam may be operated in a high frequency pulsed mode.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort.

FIG. 1 is a schematic diagram of a uniform projection electron optical structure according to an embodiment of the present application;

FIG. 2 is a schematic view of electron beam simulation of a uniform projection electron optical structure according to an embodiment of the present application.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The following describes embodiments of the present application in further detail with reference to the accompanying drawings.

Fig. 1 is a schematic view of a uniform projection electron optical structure according to an embodiment of the present application, in which 6 denotes a cathode K, 1 denotes a first gate cylinder G1, 2 denotes a second gate cylinder G2, 3 denotes a third gate cylinder G3, 4 denotes a fourth gate cylinder G4, and 5 denotes a fifth gate cylinder G5, the projection electron optical structure including: a cathode region, a beam forming region, an electron gun exit region; wherein G1 forms the cathode space, is provided with negative pole K in the cathode space, and negative pole K is parallel and level or outstanding G1 tip slightly to electron emission direction is difficult for receiving the influence of G1 in the cathode emission electron process, and then improves the cathode emission face homogeneity. The cathode K is a planar cathode and can be a thermal emission cathode or a field emission cathode, and the electron beam current can be realized by adjusting the cathode potential and the G1 potential, wherein the cathode K is 0V, and the G1 is 5V. The cathode K has extremely small capacitance to other electrodes, and the on-off of the beam current under GHz high frequency can be adjusted without influencing the reliability of the cathode K, so that the cathode K can work in a high pulse mode.

In the embodiment of the application, the planar cathode projects electrons to form a cathode emission surface, the electrons pass through the beam forming area from the cathode emission surface and then are emitted from the electron gun outlet area G5, and finally a uniform projection area is formed. The beam forming area in the implementation of the application comprises beam forming areas G2, G3 and G4, each beam forming area is of a metal cylinder structure and can be used for shielding high voltage and an external electric field of an electron gun outlet area G5, and the potential of each metal cylinder is independently adjustable, so that the electron beam form in the area can be finely controlled, and the cathode emission surface forms an inverted real image by adjusting the potential of the metal cylinder in the beam forming area. The beamlet forming regions G2 and G1 have the same diameter, G2 and G3 have the same diameter, and the distance between G1 and G2 is 0.6 + -0.1 mm, the distance between G2 and G3 is 0.5 + -0.01 mm, and the distance between G3 and G4 is 0.5 + -0.01 mm.

In the embodiment of the application, the electron gun outlet area G5 extends into the G4 by 0.25-0.5mm, and the distance between G4 and G5 can be adjusted according to the electron beam energy required to be used. And finally, the electrons pass through an outlet area of the electron gun to form a projection area, and the projection area is the secondary inverted real image of the cathode emission surface, so that the electrons are uniformly projected.

Fig. 2 is a simulation diagram of an electron beam according to an embodiment of the present invention, and it can be seen from the diagram that the projection area of the uniform projection type electron optical structure of the present invention is a secondary inverted real image of the cathode emission surface, and has no metal grid mesh, and the uniformity of the electron beam current is good.

The uniform projection type electron optical structure provided by the embodiment of the application is not provided with a metal grid, does not capture electrons, and has high utilization rate of electron beam current. Meanwhile, a high-voltage electric field is used for over-focusing, the secondary inverted real image of the electrons emitted by the cathode is projected to a required area, the electron emission uniformity of the cathode is ensured by optimizing the structures of the cathode area, the beam forming area and the electron gun outlet area, and the electron beam uniformity of the projection area is further ensured. Compared with the prior art, the electron beam current uniformity of the electron optical structure projection area is good, the reliability is high, and meanwhile, the electron beam current and the size of the projection area can be conveniently adjusted.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present application in further detail, and it should be understood that the above-mentioned embodiments are only examples of the embodiments of the present application and are not intended to limit the scope of the present application, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A uniformly projecting electron optical structure, comprising: a cathode region, a beam forming region, an electron gun exit region;

a cathode is arranged in the cathode region and projects electrons to form a cathode emission surface;

the electrons are emitted from the cathode emission surface through the beam forming area and the electron gun outlet area to finally form a uniform projection area;

the beam forming area comprises at least two beam forming areas, each beam forming area is of a metal cylinder structure, and the potential of each metal cylinder is independently adjustable and is used for controlling the electron beam form in the area; the beam forming area forms a primary inverted real image on the cathode emission surface;

the electron gun outlet area is of a metal cylinder structure, and the diameter of the metal cylinder of the electron gun outlet area is smaller than that of the metal cylinder of one beamlet forming area adjacent to the electron gun outlet area; the uniform projection area is a secondary inverted real image of the cathode emission surface, and finally the electrons are uniformly projected.

2. The uniformly projecting electron optical structure of claim 1 wherein the cathode is flush with or protrudes from an end of the cathode region.

3. The uniformly projecting electron optical structure of claim 2, wherein the cathode projects within 0.05mm when it projects from the end of the cathode region.

4. The homogeneous proj ection electron optical structure of claim 1, wherein the spacing between each beamlet-forming area is 0.5 ± 0.01 mm.

5. The homogeneous projection electron optical structure of claim 1, wherein the cathode is a thermal emission cathode or a field emission cathode.

6. The homogeneous projection electron optical structure of claim 1, wherein the beam current magnitude of the projected electrons varies with cathode potential.

7. The homogeneous projection electron optical structure of claim 1, wherein the electron gun exit region extends into an adjacent one of the beamlet-forming regions by a distance of 0.25-0.5 mm.

8. The uniformly projecting electron-optical structure of claim 1 wherein the beam-forming region comprises three beamlet-forming regions G2, G3, G4, wherein beamlet-forming region G2 is the one closest to the cathode region, and beamlet-forming regions G3 and G4 have the same barrel diameter.