Electron beam focusing method of micro-channel plate, micro-channel plate and image intensifier

Abstract

The invention relates to a micro-channel plate, in particular to an electron beam focusing method of the micro-channel plate, the micro-channel plate and an image intensifier, and solves the technical problem that the spatial resolution of the image intensifier is reduced due to the fact that the existing micro-channel plate is easy to generate an electron beam spot expansion effect. According to the electron beam focusing method of the micro-channel plate provided by the invention, the insulating dielectric layer and the modulation electrode are arranged outside the output electrode of the existing micro-channel plate, and different working voltages are applied to the output electrode and the modulation electrode, so that an electric field with electron beam focusing capability is formed between the two electrodes; the electron beams emitted by each micro-channel are focused and shaped, so that the size of an electron beam spot is reduced, and the spatial resolution is improved. Meanwhile, the modulation electrode changes the electric field distribution condition at the output electrode, so that more multiplied electrons can be emitted, and the electron gain of the micro-channel plate can be improved.

Description

Technical Field

[0001] The invention relates to a microchannel plate, and in particular to an electron beam focusing method for a microchannel plate, the microchannel plate and an image intensifier. Background Art

[0002] An image intensifier is an electro-vacuum device that achieves imaging in low-light environments through photoelectric conversion and signal amplification. It primarily consists of a photocathode, a microchannel plate, and a phosphor screen. The photocathode performs photoelectric conversion, converting the target's optical image information into an electronic image; the microchannel plate multiplies the electrons generated by the photocathode, achieving signal amplification; and the phosphor screen performs electro-optical conversion, restoring the microchannel plate's multiplied electronic image back into an optical image. As a result, image intensifiers possess high image enhancement capabilities, enabling real-time, clear display of the measured target in extremely low illumination levels (such as starlight). Due to these characteristics, image intensifiers are widely used in security, medical imaging, industrial inspection, astronomical observation, and other civilian applications.

[0003] The microchannel plate (MCP) is the core electron multiplying device of an image intensifier. It contains multiple microchannels with electron multiplication functions. Incident electrons bombard the electron multiplying material on the inner surface of the microchannels to produce secondary electrons, thereby multiplying the electron signal. When the multiplied electron signal is emitted from the MCP, the electrons move in different directions. The high electron density at the exit of the microchannels easily produces a large space charge effect. This causes the electron beam spot to expand as the electrons move from the MCP to the phosphor screen, resulting in a decrease in the spatial resolution of the image intensifier.

[0004] Based on the above problems, the spatial resolution of the image intensifier is currently improved mainly from the following three aspects: first, using a smaller microchannel plate to ensure that the electron beam spot at the output surface of the microchannel plate has a smaller size; second, reducing the electron beam movement distance, and then reducing the electron beam movement time, thereby reducing the degree of electron beam size expansion; third, increasing the acceleration voltage of the electron beam and the acceleration voltage of the microchannel plate. This method can not only further reduce the electron beam movement time, but also effectively suppress the space charge effect in the microchannel and suppress the expansion of the electron beam spot size.

[0005] All of the aforementioned methods improve spatial resolution by compressing the electron beam's motion time within the image intensifier and suppressing the space charge effect. However, because image intensifiers require high operating voltages during operation, discharges between electrodes can easily occur, affecting their proper function. To ensure the stability and reliability of image intensifiers, the degree to which the spacing between internal components can be compressed and the operating voltage of each electrode can be increased are limited, significantly limiting the improvement in spatial resolution. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problem that the existing microchannel plate is prone to produce electron beam spot expansion effect, which leads to a decrease in the spatial resolution of the image intensifier, and to provide an electron beam focusing method of a microchannel plate, a microchannel plate and an image intensifier.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for focusing an electron beam of a microchannel plate, the microchannel plate comprising a microchannel substrate, and input electrodes and output electrodes respectively disposed on upper and lower bottom surfaces of the microchannel substrate; the microchannel substrate being provided with a plurality of microchannels arranged in an array and communicating with the upper and lower bottom surfaces; and the input electrodes and the output electrodes being provided with through holes corresponding one to one with the microchannels.

[0009] Its special feature is that it includes the following steps:

[0010] Step 1: An insulating dielectric layer and a modulation electrode are sequentially provided outside the output electrode, the output electrode and the modulation electrode are insulated by the insulating dielectric layer, and then an operating voltage is applied to the input electrode, the output electrode, and the modulation electrode; the insulating dielectric layer and the modulation electrode are respectively provided with through holes corresponding to the microchannels;

[0011] Step 2: Electrons are incident on the input electrode, and the electrons are accelerated and collided in each microchannel to generate multiplied electrons, and form an electron beam that is emitted to the output electrode;

[0012] Step 3: The output electrode and the modulation electrode form a micro electric lens to focus the electron beam emitted from each microchannel individually, thereby reducing the degree of beam spot diffusion during the movement of the electron beam after passing through the modulation electrode, and achieving focusing of the electron beam.

[0013] Furthermore, step 1 is specifically as follows:

[0014] Step 1.1, set the initial thickness of the insulating dielectric layer to L0 and the thickness of the modulation electrode to L1, where H≤L0≤0.1mm, H≤L1≤10H, and H is the thickness of the output electrode;

[0015] Set the working voltage of the modulation electrode V0 = V MCP +(i-6)×i, V0≤1.5×V MCP , i is the operating voltage variation coefficient, i=1,2,3,…, V MCP is the operating voltage of the output electrode;

[0016] Step 1.2: Under the initial thickness of the insulating dielectric layer, apply operating voltages to the modulation electrode when i is 1, 2, 3, ..., respectively. Then, calculate the beam spot size of the electron beam emitted by the modulation electrode when a single electron is incident on the input electrode, and record the minimum beam spot size D of the emitted electron beam and its corresponding operating voltage of the modulation electrode;

[0017] Step 1.3: Set the thickness of the insulating dielectric layer to L0+H and L0-H respectively, and then follow the method in step 1.2 to obtain the minimum beam spot size D of the outgoing electron beam. + 、D - and its corresponding modulation electrode operating voltage;

[0018] Step 1.4: Compare D and D + and D - , if D + <D, then increase the thickness of the insulating dielectric layer in steps of H, and then follow the method in step 1.2 to obtain the minimum beam spot size of the outgoing electron beam and the corresponding modulation electrode operating voltage, until the minimum beam spot size of the outgoing electron beam no longer decreases. Then, obtain the thickness of the insulating dielectric layer and the modulation electrode operating voltage corresponding to the minimum beam spot size of the outgoing electron beam at this thickness;

[0019] If D - <D, then reduce the thickness of the insulating dielectric layer in steps of H, and then follow the method in step 1.2 to obtain the minimum beam spot size of the outgoing electron beam and the corresponding modulation electrode operating voltage, until the minimum beam spot size of the outgoing electron beam no longer decreases. Then, obtain the thickness of the insulating dielectric layer and the modulation electrode operating voltage corresponding to the minimum beam spot size of the outgoing electron beam at this thickness;

[0020] Step 1.5: According to the thickness of the insulating dielectric layer obtained in step 1.4 and the thickness of the modulation electrode set in step 1.1, an insulating dielectric layer and a modulation electrode are sequentially arranged outside the output electrode, and then the operating voltage obtained in step 1.4 is applied to the modulation electrode, and the rated operating voltage is applied to the input electrode and the output electrode.

[0021] Furthermore, in step 3, the individually focusing the electron beam emitted from each microchannel is specifically: individually focusing the electron beam emitted from each microchannel so that its focus is located on an imaging device arranged behind the microchannel plate.

[0022] The present invention further provides a microchannel plate for implementing the above-mentioned electron beam focusing method of a microchannel plate, comprising a microchannel substrate, and input electrodes and output electrodes respectively disposed on the upper and lower bottom surfaces of the microchannel substrate. The microchannel substrate is provided with a plurality of microchannels connected to the upper and lower bottom surfaces and arranged in an array, and the input electrodes and output electrodes are respectively provided with through holes corresponding to the microchannels. The microchannel plate is special in that:

[0023] It also includes an insulating dielectric layer and a modulation electrode sequentially arranged outside the output electrode;

[0024] The insulating dielectric layer and the modulation electrode are respectively provided with through holes corresponding to the microchannels, and the thickness of both is greater than or equal to the thickness of the output electrode;

[0025] The insulating dielectric layer is used to ensure the insulation between the output electrode and the modulation electrode when the working voltage is applied; the modulation electrode is used to form a micro-electric lens together with the output electrode to individually focus the electron beam emitted from each microchannel, thereby reducing the degree of beam spot diffusion during the movement of the electron beam after passing through the modulation electrode, thereby achieving focusing of the electron beam.

[0026] Furthermore, the thickness of the insulating dielectric layer is greater than or equal to the thickness of the output electrode and less than or equal to 0.1 mm;

[0027] The thickness of the modulation electrode is greater than or equal to the thickness of the output electrode and less than or equal to 10 times the thickness of the output electrode.

[0028] Furthermore, the operating voltage of the modulation electrode is less than or equal to 1.5V MCP , where V MCP is the operating voltage of the output electrode.

[0029] Furthermore, the insulating dielectric layer is made of silicon dioxide, and the modulation electrode is made of nickel.

[0030] Furthermore, the thickness of the insulating dielectric layer is 5 μm, and the thickness of the modulation electrode is 5 μm.

[0031] This embodiment further provides an image intensifier, comprising a photocathode, a microchannel plate, and a fluorescent screen arranged in sequence, wherein the image intensifier is special in that the microchannel plate is the microchannel plate described above.

[0032] Furthermore, the distance between the photocathode and the microchannel plate is 0.16 mm, and the distance between the microchannel plate and the fluorescent screen is 0.34 mm.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention provides a method for focusing an electron beam on a microchannel plate. An insulating dielectric layer and a modulation electrode are provided outside the output electrode of an existing microchannel plate. Different operating voltages are applied to the output electrode and the modulation electrode, so that an electric field with electron beam focusing capability is formed between the two electrodes. The electron beam emitted from each microchannel is focused and shaped, thereby reducing the electron beam spot size and improving spatial resolution.

[0035] 2. The microchannel plate provided by the present invention improves the spatial resolution of the microchannel plate while also changing the electric field distribution at the output electrode, thereby enabling more multiplied electrons to be emitted, thereby increasing the electron gain of the microchannel plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of a microchannel plate according to an embodiment of the present invention;

[0037] Figure 2 Schematic diagram of the structure of an image intensifier according to an embodiment of the present invention;

[0038] Figure 3 is a graph showing changes in the size of the electron beam spot on the phosphor screen of the image intensifier according to the embodiment of the present invention as a function of the operating voltage of the microchannel plate modulation electrode;

[0039] Figure 4 is a graph showing the variation of the electronic gain of the microchannel plate according to an embodiment of the present invention with the operating voltage of the modulation electrode;

[0040] The following are the descriptions of the reference numerals:

[0041] 1-microchannel substrate, 2-input electrode, 3-output electrode, 4-insulating dielectric layer, 5-modulation electrode;

[0042] 6-photocathode, 7-microchannel plate, 8-phosphor screen. DETAILED DESCRIPTION

[0043] To make the objects, advantages and features of the present invention more clear, the electron beam focusing method of a microchannel plate, the microchannel plate and the image intensifier proposed by the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] A method for focusing an electron beam of a microchannel plate, wherein the microchannel plate includes a microchannel substrate 1, and an input electrode 2 and an output electrode 3 respectively arranged on the upper and lower bottom surfaces of the microchannel substrate 1; the microchannel substrate 1 is provided with a plurality of microchannels connected to the upper and lower bottom surfaces and arranged in an array, and the input electrode 2 and the output electrode 3 are respectively provided with through holes corresponding to the microchannels; the method comprises the following steps:

[0045] Step 1: Figure 1As shown, an insulating dielectric layer 4 and a modulation electrode 5 are sequentially arranged outside the output electrode 3. The output electrode 3 and the modulation electrode 5 are insulated by the insulating dielectric layer 4. Then, an operating voltage is applied to the input electrode 2, the output electrode 3, and the modulation electrode 5. The insulating dielectric layer 4 and the modulation electrode 5 are each provided with holes corresponding to the microchannels. Specifically:

[0046] Step 1.1, set the initial thickness of the insulating dielectric layer 4 to L0 and the thickness of the modulation electrode 5 to L1, where H≤L0≤0.1mm, H≤L≤10H, and H is the thickness of the output electrode 3;

[0047] Set the working voltage of the modulation electrode 5 V0 = V MCP +(i-6)×i, V0≤1.5×V MCP , i is the operating voltage variation coefficient, i=1,2,3,…, V MCP is the operating voltage of the output electrode 3;

[0048] Step 1.2: At the initial thickness of the insulating dielectric layer 4, apply operating voltages of 1, 2, 3, ... to the modulation electrode 5, respectively. Then, calculate the spot size of the electron beam emitted from the microchannel plate when a single electron is incident on the input electrode 2, and record the minimum spot size D of the emitted electron beam and the corresponding operating voltage of the modulation electrode 5.

[0049] Step 1.3: Set the thickness of the insulating dielectric layer 4 to L0+H and L0-H respectively, and then follow the method of step 1.2 to obtain the minimum beam spot size D of the outgoing electron beam. + 、D - and its corresponding working voltage of the modulation electrode 5;

[0050] Step 1.4: Compare D and D + and D - , if D + <D, then the thickness of the insulating dielectric layer 4 is increased in steps of H, and then the method of step 1.2 is used to obtain the minimum beam spot size of the outgoing electron beam and the corresponding operating voltage of the modulation electrode 5, until the minimum beam spot size of the outgoing electron beam no longer decreases, and the thickness of the insulating dielectric layer 4 and the corresponding operating voltage of the modulation electrode 5 at the minimum beam spot size of the outgoing electron beam at this thickness are obtained;

[0051] If D - <D, then the thickness of the insulating dielectric layer 4 is reduced in steps of H, and then the method of step 1.2 is used to obtain the minimum beam spot size of the outgoing electron beam and the corresponding operating voltage of the modulation electrode 5, until the minimum beam spot size of the outgoing electron beam no longer decreases, and the thickness of the insulating dielectric layer 4 and the corresponding operating voltage of the modulation electrode 5 at the minimum beam spot size of the outgoing electron beam at this thickness are obtained;

[0052] Step 1.5: According to the thickness of the insulating dielectric layer 4 obtained in step 1.4 and the thickness of the modulation electrode 5 set in step 1.1, the insulating dielectric layer 4 and the modulation electrode 5 are sequentially arranged outside the output electrode 3, and then the working voltage obtained in step 1.4 is applied to the modulation electrode 5, and the rated working voltage is applied to the input electrode 2 and the output electrode 3.

[0053] Step 2: Electrons are incident on the input electrode 2 . The electrons are accelerated and collided in each microchannel to generate multiplied electrons, and form an electron beam that is emitted to the output electrode 3 .

[0054] Step 3: The output electrode 3 and the modulation electrode 5 form a miniature electric lens to focus the electron beam emitted by each microchannel individually so that its focus is located on the imaging device set behind the microchannel plate, thereby reducing the degree of beam spot diffusion during the movement of the electron beam after passing through the modulation electrode 5 and achieving the focusing of the electron beam.

[0055] This embodiment also provides a microchannel plate for implementing the above-mentioned electron beam focusing method of a microchannel plate, such as Figure 1 As shown, the microchannel substrate 1 includes an input electrode 2 and an output electrode 3, respectively disposed on the upper and lower bottom surfaces of the microchannel substrate 1. The microchannel substrate 1 is provided with a plurality of microchannels arranged in an array, connecting the upper and lower bottom surfaces. The input electrode 2 and the output electrode 3 each have through-holes corresponding to the microchannels. An insulating dielectric layer 4 and a modulation electrode 5 are disposed on the exterior of the output electrode 3, respectively. Each of the insulating dielectric layer 4 and the modulation electrode 5 each has through-holes corresponding to the microchannels.

[0056] The insulating dielectric layer 4 is used to ensure the insulation between the output electrode 3 and the modulation electrode 5 when the working voltage is applied. The modulation electrode 5 is used to form a micro-electric lens together with the output electrode 3 to focus the electron beam emitted from each microchannel separately, thereby reducing the degree of beam spot diffusion during the movement of the electron beam after passing through the modulation electrode 5, thereby achieving the focusing of the electron beam.

[0057] The thickness of the insulating dielectric layer 4 is greater than or equal to the thickness of the output electrode 3 and less than or equal to 0.1 mm. The thickness of the modulation electrode 5 is greater than or equal to the thickness of the output electrode 3 and less than or equal to 10 times the thickness of the output electrode 3. The operating voltage of the modulation electrode 5 is less than or equal to 1.5 V. MCP , where V MCP is the working voltage of the output electrode 3. In this embodiment, the aperture of the microchannel is set to 6 μm, the insulating dielectric layer 4 is made of silicon dioxide with a thickness of 5 μm, and the modulation electrode 5 is made of nickel with a thickness of 5 μm.

[0058] This embodiment also provides an image intensifier composed of a microchannel plate with the above structure, such as Figure 2As shown, it includes a photocathode 6, a microchannel plate 7 and a fluorescent screen 8 arranged in sequence. The distance between the photocathode 6 and the microchannel plate 7 is set to 0.16 mm, and the distance between the microchannel plate 7 and the fluorescent screen 8 is set to 0.34 mm.

[0059] Under the above structural parameters, the operating voltage of the photocathode 6 is set to 0V, the operating voltage of the microchannel plate 7 is set to 400V, and the operating voltage of the fluorescent screen 8 is set to 6000V. In the image intensifier composed of the existing microchannel plate structure, after the existing microchannel plate multiplies one electron, the size of the electron beam spot at the fluorescent screen 8 is 17.9μm, and the electron gain is 10879. In the image intensifier provided by this embodiment, under different operating voltages of the modulation electrode 5, the size of the electron beam spot at the fluorescent screen 8 after the microchannel plate 7 multiplies one electron is changed as follows Figure 3 As shown in FIG, when the working voltage of the modulation electrode 5 is 1215V, the electron beam spot size at the fluorescent screen 8 can reach 7μm, and the spatial resolution of the microchannel plate 7 is improved by 2.6 times. Figure 4 Figure 2 shows the electronic gain curve of the microchannel plate 7 at different operating voltages of the modulation electrode 5. When the operating voltage of the modulation electrode 5 is 1215 V, the electronic gain of the microchannel plate 7 is 11367, an increase of 4.5%. This shows that the microchannel plate provided in this embodiment can not only improve the spatial resolution of the image intensifier it constitutes, but also improve its electronic gain.

[0060] This embodiment provides a method for focusing an electron beam using a microchannel plate. A modulation electrode 5 is positioned at the output electrode 3 to focus the electron beam, controlling its focal point to be located on an imaging device positioned thereafter. Based on this, an image intensifier formed by a microchannel plate used to implement the above-described method modulates the focal point of the electron beam output by the microchannel plate 7 onto a fluorescent screen 8, thereby increasing the spatial resolution of the image intensifier to more than double its original spatial resolution.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for focusing an electron beam of a microchannel plate, the microchannel plate comprising a microchannel substrate (1), and an input electrode (2) and an output electrode (3) respectively arranged on the upper and lower bottom surfaces of the microchannel substrate (1); the microchannel substrate (1) is provided with a plurality of microchannels connected to the upper and lower bottom surfaces and arranged in an array; the input electrode (2) and the output electrode (3) are respectively provided with through holes corresponding to the microchannels; It is characterized by: The following steps are involved: Step 1: An insulating dielectric layer (4) and a modulation electrode (5) are sequentially arranged outside the output electrode (3), the output electrode (3) and the modulation electrode (5) are insulated by the insulating dielectric layer (4), and then a working voltage is applied to the input electrode (2), the output electrode (3) and the modulation electrode (5); the insulating dielectric layer (4) and the modulation electrode (5) are respectively provided with through holes corresponding to the microchannels; Step 2: Electrons are incident on the input electrode (2), and the electrons are accelerated and collided in each microchannel to generate multiplied electrons, and form an electron beam that is emitted to the output electrode (3); Step 3: The output electrode (3) and the modulation electrode (5) form a micro electric lens to focus the electron beam emitted from each microchannel individually, thereby reducing the degree of beam spot diffusion during the movement of the electron beam after passing through the modulation electrode (5) and achieving focusing of the electron beam.

2. The electron beam focusing method of a microchannel plate according to claim 1, characterized in that: Step 1 is as follows: Step 1.1, setting the initial thickness of the insulating dielectric layer (4) to L0 and the thickness of the modulation electrode (5) to L1, wherein H≤L0≤0.1mm, H≤L1≤10H, and H is the thickness of the output electrode 3; Set the working voltage of the modulation electrode (5) V0 = V MCP +(i-6)×i, V0≤1.5×V MCP , i is the operating voltage variation coefficient, i=1,2,3,…, V MCP is the operating voltage of the output electrode (3); Step 1.2, under the initial thickness of the insulating dielectric layer (4), applying operating voltages when i is 1, 2, 3, ... to the modulation electrode (5), and then calculating the beam spot size of the electron beam emitted by the modulation electrode (5) when a single electron is incident on the input electrode (2), and recording the minimum beam spot size D of the emitted electron beam and the corresponding operating voltage of the modulation electrode (5); Step 1.3, set the thickness of the insulating dielectric layer (4) to L0+H and L0-H respectively, and then follow the method of step 1.2 to obtain the minimum beam spot size D of the outgoing electron beam respectively. + 、D - and its corresponding modulation electrode (5) operating voltage; Step 1.4: Compare D and D + and D - , if D + <D, then the thickness of the insulating dielectric layer (4) is increased in steps of H, and then the minimum beam spot size of the outgoing electron beam and the corresponding working voltage of the modulation electrode (5) are obtained according to the method of step 1.2, until the minimum beam spot size of the outgoing electron beam no longer decreases, and the thickness of the insulating dielectric layer (4) and the working voltage of the modulation electrode (5) corresponding to the minimum beam spot size of the outgoing electron beam at this thickness are obtained; If D - <D, then the thickness of the insulating dielectric layer (4) is reduced in steps of H, and then the minimum beam spot size of the outgoing electron beam and the corresponding working voltage of the modulation electrode (5) are obtained according to the method of step 1.2, until the minimum beam spot size of the outgoing electron beam no longer decreases, and the thickness of the insulating dielectric layer (4) and the working voltage of the modulation electrode (5) corresponding to the minimum beam spot size of the outgoing electron beam at this thickness are obtained; Step 1.5: According to the thickness of the insulating dielectric layer (4) obtained in step 1.4 and the thickness of the modulation electrode (5) set in step 1.1, the insulating dielectric layer (4) and the modulation electrode (5) are sequentially arranged outside the output electrode (3), and then the operating voltage obtained in step 1.4 is applied to the modulation electrode (5), and the rated operating voltage is applied to the input electrode (2) and the output electrode (3).

3. The electron beam focusing method of a microchannel plate according to claim 1 or 2, characterized in that: In step 3, the electron beam emitted from each microchannel is individually focused, specifically: the electron beam emitted from each microchannel is individually focused so that the focus is located on the imaging device arranged behind the microchannel plate.

4. A microchannel plate for implementing the electron beam focusing method of a microchannel plate according to any one of claims 1 to 3, comprising a microchannel substrate (1), and an input electrode (2) and an output electrode (3) respectively arranged on the upper and lower bottom surfaces of the microchannel substrate (1), wherein the microchannel substrate (1) is provided with a plurality of microchannels connected to the upper and lower bottom surfaces and arranged in an array, and the input electrode (2) and the output electrode (3) are respectively provided with through holes corresponding to the microchannels; Its characteristics are: It also includes an insulating dielectric layer (4) and a modulation electrode (5) which are sequentially arranged outside the output electrode (3); The insulating dielectric layer (4) and the modulation electrode (5) are respectively provided with through holes corresponding to the microchannels, and the thickness of both is greater than or equal to the thickness of the output electrode (3); The insulating dielectric layer (4) is used to ensure insulation between the output electrode (3) and the modulation electrode (5) when an operating voltage is applied; The modulation electrode (5) is used to form a micro electric lens together with the output electrode (3) to focus the electron beam emitted from each microchannel individually, thereby reducing the degree of beam spot diffusion of the electron beam during its movement after passing through the modulation electrode (5) and achieving focusing of the electron beam.

5. The microchannel plate according to claim 4, characterized in that: The thickness of the insulating dielectric layer (4) is greater than or equal to the thickness of the output electrode (3) and less than or equal to 0.1 mm; The thickness of the modulation electrode (5) is greater than or equal to the thickness of the output electrode (3) and less than or equal to 10 times the thickness of the output electrode (3).

6. The microchannel plate according to claim 5, characterized in that: The operating voltage of the modulation electrode (5) is less than or equal to 1.5V MCP , where V MCP is the operating voltage of the output electrode (3).

7. A microchannel plate according to any one of claims 4 to 6, characterized in that: The material of the insulating dielectric layer (4) is silicon dioxide, and the material of the modulation electrode (5) is nickel.

8. The microchannel plate according to claim 7, characterized in that: The thickness of the insulating medium layer (4) is 5 μm, and the thickness of the modulation electrode (5) is 5 μm.

9. An image intensifier comprising a photocathode (6), a microchannel plate (7) and a fluorescent screen (8) arranged in sequence, characterized in that: The microchannel plate (7) is the microchannel plate according to any one of claims 4 to 8.

10. The image intensifier according to claim 9, characterized in that: The distance between the photocathode (6) and the microchannel plate (7) is 0.16 mm, and the distance between the microchannel plate (7) and the fluorescent screen (8) is 0.34 mm.

Images