Processing device and processing method of field emission cathode, and field emission cathode

Abstract

The invention provides a processing device and method of a field emission cathode and the field emission cathode, and belongs to the technical field of laser processing, and the processing device of the field emission cathode comprises a laser used for emitting laser; the beam expander is arranged at the output end of the laser and used for converting the laser into beam-expanded laser; the spatial light modulator is arranged at the output end of the beam expander and used for converting the beam-expanded laser into modulated laser according to a preset pattern; the optical scaling system is arranged at the output end of the spatial light modulator and used for converting the modulated laser into scaled laser; and the focusing objective lens is arranged at the output end of the optical zooming system and is used for converting the zoomed laser into focused laser. According to the field emission cathode processing device provided by the embodiment of the invention, the field emission cathode can be processed through laser etching, the field emission cathode with good morphology consistency and excellent uniformity can be formed, and the field emission cathode processing device is suitable for large-scale production and processing of the field emission cathode.

Description

Technical Field

[0001] The present application relates to the field of laser processing technology, and in particular to a processing device and method for a field emission cathode, and a field emission cathode. Background Art

[0002] Field emission cathode is a key component of vacuum microelectronics, and its performance is directly related to the overall performance of the device. Field emission vacuum electronic devices based on field emission cathodes have the characteristics of radiation resistance, antistatic and temperature characteristics. Among them, lanthanum hexaboride (LaB6) has the advantages of low escape power, high melting point, low evaporation rate, stable chemical properties, strong resistance to ion bombardment, and good thermal conductivity. It is an ideal material for manufacturing field emission cathodes. However, due to the stable physical and chemical properties of lanthanum hexaboride, it is difficult to process the material using conventional methods such as particle beam etching, electron beam exposure, and chemical etching, and its hard and brittle properties also make the material easy to crack when mechanical micromachining is used.

[0003] In the related art, lanthanum hexaboride field emission cathodes are usually processed by wet etching and electrochemical corrosion methods, but the surface morphology, height and bottom flatness of the lanthanum hexaboride field emission cathodes obtained by these processing methods are not ideal, and the process cycle is long. Summary of the invention

[0004] The embodiments of the present application provide a field emission cathode processing device and a processing method, and a field emission cathode, which can obtain a field emission cathode with good morphology consistency and excellent uniformity.

[0005] In a first aspect, an embodiment of the present application provides a field emission cathode processing device, comprising:

[0006] Laser, used for emitting laser light;

[0007] A beam expander is arranged at the output end of the laser and is used to convert the laser into a beam-expanded laser;

[0008] A spatial light modulator is disposed at the output end of the beam expander and is used to convert the beam expanded laser into a modulated laser according to a preset pattern;

[0009] An optical zoom system, arranged at the output end of the spatial light modulator, for converting the modulated laser into zoomed laser;

[0010] The focusing objective lens is arranged at the output end of the optical zoom system and is used to convert the zoom laser into the focusing laser.

[0011] In some embodiments, the processing device for the field emission cathode further includes a 1 / 2 glass slide and a 1 / 4 glass slide;

[0012] Wherein, the 1 / 2 glass plate is arranged between the output end of the beam expander and the receiving end of the spatial light modulator;

[0013] The 1 / 4 glass slide is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

[0014] In some embodiments, it also includes a beam splitter prism and a power receiving feedback device;

[0015] The beam splitter prism is arranged between the 1 / 2 glass slide and the receiving end of the spatial light modulator;

[0016] The first light beam output by the beam splitter prism enters the spatial light modulator, and the second light beam output by the beam splitter prism enters the power receiving feedback device.

[0017] In some embodiments, the field emission cathode processing apparatus further includes a moving platform;

[0018] The mobile platform is arranged at the output end of the focusing objective lens, and is used for carrying the workpiece to be processed and adjusting the relative position between the workpiece to be processed and the focusing objective lens.

[0019] In some embodiments, the processing apparatus for the field emission cathode further includes a first reflector and a second reflector;

[0020] The first reflector is arranged between the output end of the beam expander and the receiving end of the beam splitter prism;

[0021] The second reflecting mirror is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

[0022] In some embodiments, the laser comprises a green femtosecond laser; the repetition frequency of the laser is ≤1 MHz, the pulse width is <250 fs, and the average power is ≤20 W;

[0023] And / or, the optical zoom system includes a first lens and a second lens; the first lens is arranged between the output end of the spatial light modulator and the receiving end of the focusing objective lens; the second lens is arranged between the first lens and the receiving end of the focusing objective lens; wherein the focal length of the first lens is smaller than the focal length of the second lens.

[0024] In a second aspect, an embodiment of the present application further provides a method for processing a field emission cathode, based on the processing device for the field emission cathode as described above, comprising:

[0025] Place the workpiece to be processed at the output end of the focusing objective lens;

[0026] The laser is controlled to emit laser, and the beam expander expands the laser beam to form an expanded beam laser;

[0027] The spatial light modulator converts the expanded laser light into a modulated laser light according to a preset pattern;

[0028] The optical zoom system adjusts the pixel size of the modulated laser to form a zoomed laser;

[0029] The focusing objective lens converts the zoomed laser into a focused laser, and causes the focused laser to etch the surface of the workpiece to be processed to obtain a field emission cathode.

[0030] In some embodiments, after the focused laser is used to etch the surface of the workpiece to be processed, the process further includes:

[0031] The relative position between the workpiece to be processed and the focusing objective lens is adjusted to perform etching again.

[0032] In a third aspect, an embodiment of the present application further provides a field emission cathode, which is manufactured using the field emission cathode processing device as described above, or the field emission cathode processing method as described above.

[0033] In some embodiments, the field emission cathode is made of lanthanum hexaboride.

[0034] Beneficial effects of the embodiments of the present application:

[0035] The processing device of the field emission cathode provided in the embodiment of the present application includes a laser, a beam expander, a spatial light modulator, an optical zoom system and a focusing objective lens. Among them, the laser can emit laser, the beam expander is arranged at the output end of the laser, the spatial light modulator is arranged at the output end of the beam expander, the optical zoom system is arranged at the output end of the spatial light modulator, and the focusing objective lens is arranged at the output end of the optical zoom system. The laser emitted by the laser forms a beam expansion laser after passing through the beam expander. After the beam expansion laser passes through the spatial light modulator, it can form a modulated laser according to a preset pattern. The modulated laser is scaled by the optical zoom system to obtain a scaled laser of a suitable pixel size, and then through the focusing objective lens, the focused laser is made to act on the workpiece to be processed, and the laser etching of the workpiece to be processed is completed. The etching precision of laser etching is high, the stability is good, the process is simple, and the field emission cathode with good morphology consistency and excellent uniformity can be formed, which is suitable for large-scale production and processing of field emission cathodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a schematic structural diagram of a field emission cathode processing device provided in an embodiment of the present application;

[0038] Figure 2 It is a schematic flow chart of a method for processing a field emission cathode provided in an embodiment of the present application;

[0039] Figure 3 It is a schematic diagram of the structure of the field emission cathode provided in the embodiment of the present application.

[0040] Description of reference numerals:

[0041] 1. Laser; 2. Beam expander; 3. Spatial light modulator; 4. Optical zoom system; 41. First lens; 42. Second lens; 5. Focusing objective lens; 6. Moving platform; 7. 1 / 2 glass slide; 8. 1 / 4 glass slide; 9. Beam splitter; 10. Power receiving feedback device; 11. First reflector; 12. Second reflector; 20. Field emission cathode; 21. Conical structure. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions 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 those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0043] First, as Figure 1 As shown, the processing device of the field emission cathode provided in the embodiment of the present application includes a laser 1, a beam expander, a spatial light modulator 3, an optical zoom system 4 and a focusing objective lens 5. Among them, the laser 1 can emit laser light, the beam expander is arranged at the output end of the laser 1, the spatial light modulator 3 is arranged at the output end of the beam expander, the optical zoom system 4 is arranged at the output end of the spatial light modulator 3, and the focusing objective lens 5 is arranged at the output end of the optical zoom system 4. The laser emitted by the laser 1 forms an expanded beam laser after passing through the beam expander. After the expanded beam laser passes through the spatial light modulator 3, it can form a modulated laser according to a preset pattern. The modulated laser is scaled by the optical zoom system 4 to obtain a scaled laser of a suitable pixel size, and then the focused laser is applied to the workpiece to be processed through the focusing objective lens 5 to complete the laser etching of the workpiece to be processed. The laser etching has high etching precision, good stability, simple process, and can form a field emission cathode with good morphology consistency and excellent uniformity, which is suitable for large-scale production and processing of field emission cathodes.

[0044] Specifically, the beam expander can expand the laser emitted by the laser 1 to form an expanded laser, increase the diameter of the light beam, and reduce the divergence of the light beam, which is helpful for subsequent modulation by the spatial light modulator 3. The spatial light modulator 3 can modulate and split the expanded laser according to a preset pattern to form a modulated laser. After the modulated laser is scaled by the optical zoom system 4, a scaled laser with a suitable pixel size is formed, and then a focused laser is formed by the focusing objective lens 5, and then the workpiece to be processed is laser etched. Compared with the wet etching, oxygen plasma oxidation or argon plasma dry etching of the oxide layer combined method, oxygen plasma oxidation and hydrochloric acid wet etching of the oxide layer combined method, electrochemical etching and other processes in the related art, laser etching has higher precision, good stability, simple process, and can form a field emission cathode with good morphology consistency and excellent uniformity, which is suitable for large-scale production and processing of field emission cathodes.

[0045] In some embodiments, Figure 1 As shown, the processing device of the field emission cathode also includes a 1 / 2 glass slide 7 and a 1 / 4 glass slide 8. The 1 / 2 glass slide 7 is arranged between the output end of the beam expander and the receiving end of the spatial light modulator 3, and the 1 / 4 glass slide 8 is arranged between the output end of the spatial light modulator 3 and the receiving end of the optical zoom system 4.

[0046] The 1 / 2 glass slide 7 can convert the incident linearly polarized light into circularly polarized light, that is, convert the beam expanding laser from linearly polarized light into circularly polarized light. The circularly polarized light rotates continuously during the propagation process and has rotational symmetry. When it enters the spatial light modulator 3, it is not affected by the slight deviation of the internal optical path or components of the spatial light modulator 3, thereby ensuring the stability and reliability of the beam expanding laser transmission. In addition, the two polarization states (left-handed and right-handed) of circularly polarized light are used to help realize multiple modulation methods.

[0047] The 1 / 4 glass slide 8 can convert the incident circularly polarized light into linearly polarized light, that is, convert the modulated laser output by the spatial light modulator 3 from circularly polarized light into linearly polarized light. Linearly polarized light has the directional property of the electric field vector, which will produce directional ablation on the material, so that the direction and depth of ablation can be more accurately controlled, which helps to achieve high-precision etching and ensure the morphological consistency of the field emission cathode.

[0048] In some embodiments, Figure 1 As shown, the processing device of the field emission cathode also includes a beam splitter prism 9 and a power receiving feedback device 10. The beam splitter prism 9 is arranged between the 1 / 2 glass slide 7 and the receiving end of the spatial light modulator 3. The first light beam output by the beam splitter prism 9 enters the spatial light modulator 3, and the second light beam output by the beam splitter prism 9 enters the power receiving feedback device 10.

[0049] The beam-expanding laser can be divided into a first beam and a second beam by the beam splitter prism 9, wherein the first beam can be incident on the spatial light modulator 3, and after being modulated, scaled and focused, the workpiece to be processed is laser etched, and the second beam can be transmitted to the power receiving feedback device 10, and the power receiving feedback device 10 can monitor the power of the beam-expanding laser, and then adjust the laser 1 to ensure the stability of the beam-expanding laser incident on the spatial light modulator 3, and to ensure the accuracy and consistency of the field emission cathode.

[0050] Wherein, the beam splitter prism 9 may be a PBS beam splitter prism 9 (polarization beam splitter prism 9) capable of splitting the incident laser into two mutually perpendicular beams, one of which is reflected and the other is transmitted. Exemplarily, after the beam expansion laser passes through the PBS beam splitter prism 9, 90% of the energy of the beam expansion laser is reflected to the spatial light modulator 3 to ensure that the laser etching has sufficient energy, and 10% of the energy is transmitted to the power receiving feedback device 10 to control the energy of the beam expansion laser. The processing device of the field emission cathode can adjust the power of the laser 1 according to the monitoring situation to ensure the stability of the beam expansion laser incident on the spatial light modulator 3.

[0051] In some embodiments, Figure 1 As shown, the field emission cathode processing device further includes a moving platform 6. The moving platform 6 is disposed at the output end of the focusing lens 5, and is used to carry the workpiece to be processed and adjust the relative position between the workpiece to be processed and the focusing lens 5.

[0052] The movable platform 6 can carry the workpiece to be processed, and adjust the relative position between the workpiece to be processed and the focusing objective lens 5, so as to achieve the purpose of laser etching different positions in the workpiece to be processed.

[0053] Among them, the movable platform 6 can be a three-axis movable platform 6, that is, it can be adjusted in the front-back direction, the up-down direction and the left-right direction, and can drive the workpiece to be processed to move in the front-back direction, the up-down direction and the left-right direction, so as to perform laser etching on different positions of the workpiece to be processed.

[0054] Exemplarily, the mobile platform 6 can select the L-306.011112 precision Z-axis translation stage of PI Company, with an effective Z-axis stroke of 13 mm, a minimum displacement of 0.1 μm, and a unidirectional repeatability of 0.1 μm, which can meet the processing accuracy requirements of the field emission cathode.

[0055] In some embodiments, Figure 1 As shown, the processing device of the field emission cathode also includes a first reflector 11 and a second reflector 12. The first reflector 11 is arranged between the output end of the beam expander and the receiving end of the beam splitter prism 9, and the second reflector 12 is arranged between the output end of the spatial light modulator 3 and the receiving end of the optical zoom system 4.

[0056] The laser beam can be reflected by the first emitting mirror and the second emitting mirror, thereby changing the direction of the laser beam. By properly setting the positions and angles of the first reflecting mirror 11 and the second reflecting mirror 12, it is helpful to arrange the components in the processing device of the field emission cathode and reduce the space occupied.

[0057] In some embodiments, the laser 1 comprises a green femtosecond laser 1. The repetition frequency of the laser 1 is ≤1 MHz, the pulse width is <250 fs, and the average power is ≤20 W.

[0058] The green femtosecond laser 1 has an ultra-short pulse width and a high repetition rate, and can release extremely high energy in a very short time, thus contributing to the realization of precise and efficient processing.

[0059] Exemplarily, the laser 1 may be a GS-FGN20 series 515 nm green light femtosecond laser 1 produced by Wuhan Raycus Fiber Laser Technology Co., Ltd.

[0060] In some embodiments, Figure 1 As shown, the optical zoom system 4 includes a first lens 41 and a second lens 42. The first lens 41 is arranged between the output end of the spatial light modulator 3 and the receiving end of the focusing lens 5, and the second lens 42 is arranged between the first lens 41 and the receiving end of the focusing lens 5. The focal length of the first lens 41 is smaller than the focal length of the second lens 42.

[0061] By setting the positions and focal lengths of the first lens 41 and the second lens 42 , the pixels of the modulated laser emitted by the spatial light modulator 3 can be reduced, thereby ensuring the accuracy of laser etching and meeting the processing requirements of the field emission cathode.

[0062] In some embodiments, the wavelength range of the spatial light modulator 3 is 532 nm±50 nm, the pixel is 1920×1200, and the pixel size is 7.8 μm.

[0063] Exemplarily, the spatial light modulator 3 may be a SLM-310-G spatial light modulator 3 produced by Santec.

[0064] In some embodiments, the beam expander is a 3x beam expander. Exemplarily, the diameter of the laser emitted by the laser 1 is 2 mm, and after being expanded by the beam expander, a beam expanded laser with a diameter of 6 mm can be formed.

[0065] In some embodiments, the focal length of the first lens 41 in the optical zoom system 4 is 25 mm, and the focal length of the second lens 42 is 190 mm. That is, the zoom factor of the optical zoom system 4 is about 7.6 times. The pixel of the modulated laser emitted by the spatial light modulator 3 is 7.8 μm, and after being zoomed by the optical zoom system 4, a pattern with a pixel of 1.03 μm is formed, thereby realizing micron-level laser etching.

[0066] In some embodiments, the numerical aperture of the focusing objective lens 5 is 2, the focal length is 2 mm, the wavelength is 515 nm, the field diameter is 6.5 mm, and the resolution is 0.24 μm, thereby ensuring a good focusing effect.

[0067] In a second aspect, the embodiments of the present application also provide a method for processing a field emission cathode, such as Figure 2 As shown, a processing device based on the field emission cathode as described above comprises:

[0068] S1, placing the workpiece to be processed at the output end of the focusing objective lens 5;

[0069] S2, controlling laser 1 to emit laser, and the beam expander expands the laser beam to form an expanded beam laser;

[0070] S3, spatial light modulator 3 converts the beam expansion laser into modulated laser according to a preset pattern;

[0071] S4, the optical zoom system 4 adjusts the pixel size of the modulated laser to form a zoomed laser;

[0072] S5, the focusing objective lens 5 converts the zoomed laser into a focused laser, and causes the focused laser to etch the surface of the workpiece to be processed to obtain a field emission cathode.

[0073] The method for processing a field emission cathode provided in the embodiment of the present application has all the technical effects of the device for processing a field emission cathode, which will not be described in detail here.

[0074] In some embodiments, placing the workpiece to be processed at the output end of the focusing lens 5 includes:

[0075] The workpiece to be processed is placed on the moving platform 6 located at the output end of the focusing lens 5 .

[0076] By placing the workpiece to be processed on the movable platform 6, the relative position between the workpiece to be processed and the focusing objective lens 5 can be adjusted by the movable platform 6, thereby achieving the purpose of laser etching different positions in the workpiece to be processed.

[0077] In some embodiments, after the focused laser is used to etch the surface of the workpiece to be processed, the process further includes:

[0078] The relative position between the workpiece to be processed and the focusing lens 5 is adjusted to perform etching again.

[0079] That is, after etching the workpiece to be processed, the position is changed and other positions of the workpiece to be processed are etched, so that a field emission cathode array of appropriate size is formed on the surface of the workpiece to be processed.

[0080] Among them, adjusting the relative position of the workpiece to be processed and the focusing objective lens 5 includes adjusting the distance between the workpiece to be processed and the focusing objective lens 5, so as to perform laser etching on different depths of the workpiece to be processed; it also includes adjusting the relative position of the workpiece to be processed and the focusing objective lens 5 in the front-to-back and left-to-right directions, so as to perform laser etching on different areas on the workpiece to be processed.

[0081] For example, when a lanthanum hexaboride substrate with a thickness of 5 μm is processed to form a field emission cathode with a height of 3 μm, the lanthanum hexaboride substrate can be laser etched by moving up one layer at a time interval of 0.1 μm. By adjusting the preset pattern of each layer of etching, the morphology of the formed field emission cathode can be controlled, and the etching of a field emission cathode with a height of 3 μm can be completed by moving up 30 layers cumulatively.

[0082] It can be understood that the processing method of the field emission cathode provided in the embodiment of the present application corresponds to the processing device of the field emission cathode as described above, and also includes converting linear polarized light into circular polarized light through a 1 / 2 glass slide 7, converting circular polarized light into linear polarized light through a 1 / 4 glass slide 8, and performing splitting and power monitoring through a splitter prism 9 and a power receiving feedback device 10, etc., which will not be repeated here.

[0083] In a third aspect, the embodiments of the present application further provide a field emission cathode 20, which is manufactured using the field emission cathode processing device as described above, or the field emission cathode processing method as described above.

[0084] By using the field emission cathode processing device or the field emission cathode processing method, the field emission cathode can be prepared by laser etching, thereby ensuring the morphology consistency and uniformity of the field emission cathode 20 and improving the performance of the field emission cathode.

[0085] In some embodiments, the material of the field emission cathode 20 is lanthanum hexaboride. Lanthanum hexaboride has stable physical and chemical properties and hard and brittle characteristics, which makes it difficult to process. Through the field emission cathode processing device or field emission cathode processing method provided by the present application, the processing of the lanthanum hexaboride field emission cathode can be achieved by a laser etching method. The laser etching has high precision, good stability, and a simple process, which helps to form a field emission cathode 20 with good morphology consistency and excellent uniformity, and is suitable for large-scale production and processing of the field emission cathode 20.

[0086] Since lanthanum hexaboride has the advantages of low escape power, high melting point, low evaporation rate, stable chemical properties, strong resistance to ion bombardment, and good thermal conductivity, it can improve the performance of field emission cathodes.

[0087] In some embodiments, Figure 3As shown, the field emission cathode 20 includes a plurality of cone structures 21 arranged in an array. The cone structures 21 have a height of 3 μm and a bottom radius of 4 μm; and / or, the spacing between adjacent cone structures 21 is 8 μm; and / or, the array density of the cone structures 21 is 2×10 6 tips / cm 2 .

[0088] By setting the parameters of the field emission cathode 20, the electric field can be more effectively concentrated, thereby reducing the threshold voltage of electron emission, ensuring the stability of the structure, reducing the electric field interference between adjacent conical structures 21, and having a higher electron emission capability and a more uniform electron beam distribution.

[0089] It is understandable that the field emission cathode may also have other structures, and the parameters may also be adjusted according to specific requirements.

[0090] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A field emission cathode processing device, characterized in that: include: Laser, used for emitting laser light; A beam expander, disposed at the output end of the laser, for converting the laser into a beam-expanded laser; A spatial light modulator, disposed at the output end of the beam expander, for converting the beam expanded laser into a modulated laser according to a preset pattern; An optical zoom system, arranged at the output end of the spatial light modulator, for converting the modulated laser into zoomed laser; The focusing objective lens is arranged at the output end of the optical zoom system and is used to convert the zoom laser into a focusing laser.

2. The field emission cathode processing device according to claim 1, characterized in that: Also includes 1 / 2 slides and 1 / 4 slides; Wherein, the 1 / 2 glass sheet is arranged between the output end of the beam expander and the receiving end of the spatial light modulator; The 1 / 4 glass slide is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

3. The field emission cathode processing device according to claim 2, characterized in that: It also includes a beam splitter prism and a power receiving feedback device; The beam splitter prism is arranged between the 1 / 2 glass slide and the receiving end of the spatial light modulator; The first light beam output by the beam splitter prism enters the spatial light modulator, and the second light beam output by the beam splitter prism enters the power receiving feedback device.

4. The field emission cathode processing device according to claim 1, characterized in that: Also includes mobile platforms; The movable platform is arranged at the output end of the focusing objective lens, and is used for carrying the workpiece to be processed and adjusting the relative position between the workpiece to be processed and the focusing objective lens.

5. The field emission cathode processing device according to claim 3, characterized in that: Also includes a first reflector and a second reflector; The first reflector is arranged between the output end of the beam expander and the receiving end of the beam splitter prism; The second reflector is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

6. The field emission cathode processing device according to any one of claims 1 to 5, characterized in that: The laser comprises a green light femtosecond laser; the repetition frequency of the laser is ≤1 MHz, the pulse width is <250 fs, and the average power is ≤20 W; And / or, the optical zoom system includes a first lens and a second lens; the first lens is arranged between the output end of the spatial light modulator and the receiving end of the focusing objective lens; the second lens is arranged between the first lens and the receiving end of the focusing objective lens; wherein the focal length of the first lens is smaller than the focal length of the second lens.

7. A method for processing a field emission cathode, based on the processing device for a field emission cathode according to any one of claims 1 to 6, characterized in that: include: Place the workpiece to be processed at the output end of the focusing objective lens; Controlling the laser to emit laser light, and the beam expander expands the laser light to form expanded-beam laser light; The spatial light modulator converts the beam-expanded laser into a modulated laser according to a preset pattern; The optical zoom system adjusts the pixel size of the modulated laser to form a zoomed laser; The focusing objective lens converts the zoom laser into a focused laser, and enables the focused laser to etch the surface of the workpiece to be processed to obtain a field emission cathode.

8. The method for processing a field emission cathode according to claim 7, characterized in that: After the focused laser is used to etch the surface of the workpiece to be processed, the method further comprises: The relative position between the workpiece to be processed and the focusing objective lens is adjusted to perform etching again.

9. A field emission cathode, characterized in that: The field emission cathode is manufactured by using the field emission cathode processing device as described in any one of claims 1 to 6, or by using the field emission cathode processing method as described in claim 7 or 8.

10. The field emission cathode according to claim 9, characterized in that: The field emission cathode is made of lanthanum hexaboride.

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