An image intensifier having Al ₂ O ₃ A -NiCr microchannel plate

Abstract

The application relates to the technical field of micro-light imaging, and discloses an image intensifier with a micro-channel plate, which comprises, from top to bottom, a photocathode, a micro-channel plate and a fluorescent screen. The micro-channel plate comprises a lead silicate glass substrate with hundreds of thousands of electron multiplication channels, an input electrode located at the incident end of the channels, an output electrode located at the outgoing end of the channels and a channel inner wall forming the inner surface of the channels. The surface layer of the input electrode and the channel inner wall is a material layer, and the surface layer of the output electrode is a NiCr material layer. The input electrode and the channel inner wall adopt a material layer with a high secondary electron emission coefficient to ensure high gain; the output electrode adopts a NiCr material layer with a low secondary electron emission coefficient to absorb large-angle electrons and collimate the output electron beam, thereby improving the spatial resolution, effectively solving the mutual restriction relationship between the spatial resolution and the gain in the existing micro-channel plate and realizing high-brightness and high-definition imaging.

Description

Technical Field

[0001] This application relates to the technical field of low-light imaging, and discloses a method possessing Image intensifier for microchannel plates. Background Technology

[0002] In existing technologies, there is a significant mutual constraint between the spatial resolution and gain of image intensifiers. There are still many shortcomings in how image intensifiers can achieve high spatial resolution while ensuring high gain. For example, the conventional methods to improve the spatial resolution of microchannel plates are mainly to reduce the channel aperture and increase the immersion depth of the output electrode. However, due to the limitation of the optimal aspect ratio of microchannel plates, reducing the multiplication channel aperture inevitably requires reducing the substrate thickness, which not only leads to a significant decrease in mechanical strength, but also increases the difficulty of development and use, and will directly lead to the deterioration of gain due to the small size. Since the output electrode of the microchannel plate is made of NiCr alloy electrode material, the secondary electron emission coefficient is extremely low and the electron multiplication capability is weak. As the electrode immersion depth increases, the proportion of electrode areas without multiplication capability in the channel increases, the effective multiplication area decreases, and the overall gain decreases. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of the embodiments of this application and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents, and such simplifications or omissions should not be construed as limiting the scope of this application.

[0004] The specific inventive objective of this application is as follows: This application aims to solve the technical problems of spatial resolution and gain being mutually constrained in existing microchannel plates, and gain decreasing with increasing output electrode immersion depth, and to provide a method that can achieve synergistic optimization of gain and resolution. Microchannel plate image intensifier.

[0005] While achieving the above improvements, ensure that the spatial resolution and gain level of the device are no lower than those of existing technical solutions.

[0006] To solve the above-mentioned technical problems, this application provides a method possessing Image intensifier for microchannel plates.

[0007] On the one hand, this application provides a method for possessing The image intensifier of the microchannel plate includes: Photocathode, Microchannel plates and fluorescent screens are arranged sequentially from the top to the bottom of the image intensifier.

[0008] The photocathode is used to receive incident light and generate an external photoelectric effect to complete photoelectric conversion; The The microchannel plates are arranged in the following order from the direction of electron propagation: A lead silicate glass substrate, wherein a plurality of electron multiplication channels are densely arranged in the substrate; The input electrode is located at the incident end of the electron multiplication channel, facing the photocathode; The output electrode is located at the emission end of the electron multiplication channel, facing the fluorescent screen; The inner wall of the channel forms the inner surface of the electron multiplication channel; The input electrode and the surface layer of the inner wall of the channel are Material layer; The surface layer of the output electrode is a NiCr material layer; The NiCr material layer is used to absorb electrons whose emission angle exceeds the threshold and to collimate the output electron beam.

[0009] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The input electrode and the inner wall surface of the channel The material layer is formed by atomic layer deposition. The material layer is a continuous film layer uniformly vapor-deposited on the surface and inside the channel of a traditional microchannel plate.

[0010] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The NiCr material layer on the surface of the output electrode is formed by thermal evaporation on the already deposited electrode. At the output electrode of the microchannel plate in the material layer.

[0011] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The immersion depth of the NiCr material layer in the output electrode is controlled by adjusting the angle between the evaporation source and the output plane of the substrate; The larger the angle, the shallower the vapor deposition depth; the smaller the angle, the deeper the vapor deposition depth.

[0012] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The material layer between the input electrode and the inner wall surface of the channel can be replaced with MgO material. Material; The MgO material also exhibits high secondary electron emission characteristics.

[0013] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The The microchannel plates consist of one to three pieces. Two microchannel plates are stacked in a V-shape, and three microchannel plates are stacked in a Z-shape.

[0014] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The photocathode is located at the top of the image intensifier and is used to convert incident light into photoelectrons. The material is infrared Ag-O-Cs. The A microchannel plate, located directly below the photocathode, is used to multiply the photoelectrons; Fluorescent screen, located in the Directly below the microchannel plate, a fluorescent screen is used to convert the multiplied electrons into a visible light image; the screen is a P20-AF. The photocathode, the The microchannel plate and the fluorescent screen are arranged sequentially from the top to the bottom of the image intensifier.

[0015] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The photocathode, the Both the microchannel plate and the fluorescent screen are circular in shape; The size of the photocathode is smaller than that of the The dimensions of the microchannel plate, the The size of the microchannel plate is smaller than the size of the fluorescent screen.

[0016] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: During operation, the photocathode, Microchannel plate input electrodes, The voltage applied to the output electrodes of the microchannel plate and the fluorescent screen increases gradually from low to high.

[0017] As a kind of possession in this application A preferred embodiment of an image intensifier for a microchannel plate, wherein: The The material layer is a continuous film layer formed on the surface of the input electrode and the inner wall of the channel by atomic layer deposition. The NiCr material layer is an electrode layer formed on the surface of the output electrode by thermal evaporation, and its immersion depth is defined by the angle between the evaporation source and the output plane of the substrate.

[0018] In the image intensifier described in this application, as a preferred embodiment, the applied voltage during operation increases sequentially along the photoelectron transmission direction, that is, the photocathode voltage, the microchannel plate input electrode voltage, the microchannel plate output electrode voltage, and the fluorescent screen voltage increase step by step from low to high.

[0019] This application also provides a technical solution as described above. The method for preparing microchannel plates includes the following steps: A substrate is provided, the substrate being a solid lead silicate glass having densely arranged electron multiplication channels thereon; The input electrode and the inner wall surface of the electron multiplication channel of the substrate are uniformly deposited by atomic layer deposition. Material layer; In the already evaporated A NiCr material layer is formed on the surface of the substrate output electrode by thermal evaporation. The immersion depth of the NiCr material layer in the output electrode is controlled by adjusting the angle between the evaporation source and the output plane of the substrate.

[0020] The beneficial effects of this application are as follows: This application employs a NiCr material layer with a low secondary electron emission coefficient for the output electrode, which absorbs electrons with emission angles exceeding a threshold, effectively suppressing lateral divergence of the electron beam and collimating the output electron beam. This reduces the speckle diameter of the electron beam on the phosphor screen, thereby improving the spatial resolution of the image intensifier. The input electrode and the inner wall of the channel employ materials with a high secondary electron emission coefficient. The material layer ensures a high output of secondary electrons within the channel, improving gain and overcoming the technical defect of traditional microchannel plates that sacrifice gain to improve resolution.

[0021] This application utilizes atomic layer deposition (ALD) for vapor deposition. The material layer can achieve uniform and dense film coverage on the inner walls of hundreds of thousands of high aspect ratio multiplication channels; the NiCr output electrode layer is deposited by thermal evaporation, and the electrode immersion depth is controlled by adjusting the angle between the evaporation source and the output plane of the substrate. The process is compatible with existing microchannel plate manufacturing lines, without the need for additional special equipment development, making it easy to achieve large-scale production and reducing production costs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained through these drawings without creative effort. Wherein: Figure 1 This application provides a kind of possession Schematic diagram of an image intensifier for a microchannel plate; Figure 2 For different output electrode immersion depths, the Glass-NiCr microchannel plate image intensifier provided by this invention... Microchannel plate image intensifier The speckle distribution (FWHM) on the phosphor screen of a microchannel plate image intensifier. Figure 3 To provide an image intensifier for Glass-NiCr microchannel plates at different output electrode immersion depths, the present invention... Microchannel plate image intensifier Microchannel plate image intensifier gain statistics; In the diagram: 1. Photocathode; 2. Microchannel plate input electrode; 3. Microchannel plate for channel multiplication; 4. Microchannel plate lead-silicate glass substrate; 5. 6. Microchannel plate output electrode; 7. Fluorescent screen. Detailed Implementation

[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0026] Example 1 like Figure 1 As shown, this embodiment provides a method with The image intensifier of the microchannel plate includes a photocathode 1, Microchannel plate, fluorescent screen 6.

[0027] Photocathode 1, used to convert incident light into photoelectrons, is located at the top of the image intensifier. In this embodiment, photocathode 1 is made of polyalkali Na2KCsSb material, is circular in shape, and has a diameter of 24 mm. The voltage applied to photocathode 1 is the lowest in the entire image intensifier; in this embodiment, it is set to 0V. The surface of photocathode 1 is parallel to... The microchannel plate has two input electrodes with a distance of 200 μm between them.

[0028] The microchannel plate, used for photoelectron multiplication, is located directly below the photocathode 1. Microchannel plates include 2. Microchannel plate input electrode; 3. Densely arranged electron multiplication channels. Microchannel plate lead silicate glass substrate 4 Microchannel plate output electrode 5.

[0029] In this embodiment, The microchannel plate is circular, with a diameter of 25 mm and a thickness of 0.32 mm. The microchannel plate lead silicate glass substrate 4 is made of lead glass material, and its secondary electron emission coefficient peak value is 3.7 (when the main electron energy is 320eV). The microchannel multiplication channel 3 has a diameter of 6 μm and an inclination angle of 7°. The inner wall surface of the channel is uniformly coated with... Material layer.

[0030] The material layer is formed by atomic layer deposition and has high secondary electron emission characteristics. When the primary electron energy is 650eV, its secondary electron emission coefficient can reach up to 6.4.

[0031] The microchannel plate input electrode 2 is located at the electron incident end of the multiplication channel 3, facing the photocathode 1, and its surface is also coated with... Material layer. In this embodiment, the input electrode 2 is immersed to a depth of 0.5 times the channel aperture, i.e., 3 μm. The voltage applied to the input electrode 2 is 100V, which is higher than the voltage of the photocathode 1.

[0032] The microchannel plate output electrode 5 is located at the emission end of the multiplication channel 3, facing the fluorescent screen 6, and its surface is a NiCr material layer. The NiCr material layer is formed on the pre-deposited substrate by thermal evaporation. At the output electrode of the microchannel plate in the material layer, the secondary electron emission coefficient is low, which is used to absorb electrons whose emission angle exceeds the threshold and to collimate the output electron beam.

[0033] It should be noted that the emission angle threshold is determined by the channel diameter and the immersion depth of the output electrode.

[0034] In this embodiment, The microchannel plate output electrode 5 is immersed to a depth of twice the channel aperture, i.e., 12 μm. The voltage applied to the output electrode 5 is 1100V, which is higher than the voltage of the input electrode 2.

[0035] NiCr material layer in The immersion depth of the microchannel plate output electrode 5 is controlled by adjusting the angle between the evaporation source and the output plane of the substrate. In this embodiment, the immersion depth is 12 μm.

[0036] The fluorescent screen 6 is used to convert the multiplied electrons into a visible light image and is located directly below the microchannel plate.

[0037] In this embodiment, the fluorescent screen 6 is made of P43 fluorescent material, is circular in shape, and has a diameter of 26 mm. The surface of the fluorescent screen 6 is parallel to... The microchannel plate has five output electrodes, spaced 200 μm apart. The fluorescent screen (6) is supplied with a voltage of 1200 V, which is higher than... The voltage at the microchannel plate output electrode 5 is the highest in the entire image intensifier.

[0038] This embodiment Microchannel plates are prepared using the following steps: S1: Provide a lead silicate glass substrate 4, on which electron multiplication channels 3 are densely arranged; S2: Formed by uniformly vapor-depositing on the surface of lead silicate glass substrate 4, input electrode, output electrode, and inner wall of the channel using atomic layer deposition. Material layer; S3: In the already evaporated deposit A NiCr material layer is formed on the surface of the output electrode 5 of the substrate 4 of the material layer by thermal evaporation. S4: By adjusting the angle between the evaporation source and the output plane of the substrate 4, the immersion depth of the NiCr material layer in the output electrode 5 is controlled.

[0039] Example 2 This embodiment is basically the same as embodiment 1, except that the microchannel plate adopts a combination structure of two pieces stacked in a V-shape.

[0040] In this embodiment, two pieces The microchannel plates are arranged in a V-shape, which can further suppress ion feedback and improve the signal-to-noise ratio and service life of the image intensifier.

[0041] Both microchannel plates have a channel diameter of 6 μm and an inclination angle of 7°, and are arranged in opposite inclination directions to form a V-shaped structure. The inner walls of both the input electrode 2 and the multiplication channel 3 are deposited using atomic layer deposition. Both the material layer and the output electrode 5 are deposited with NiCr material layer by thermal evaporation.

[0042] In this embodiment, the NiCr material layer of the output electrode 5 of the first microchannel plate is immersed to a depth of 1.5 times the channel aperture, and the NiCr material layer of the output electrode 5 of the second microchannel plate is immersed to a depth of 2 times the channel aperture. The voltage configurations of the two microchannel plates increase sequentially to accommodate the cascading multiplication requirements.

[0043] Example 3 This embodiment is the same as Embodiment 1, the main difference being that: the high secondary electron emission material layer on the inner wall surface of the input electrode 2 and the multiplication channel 3 is replaced with MgO. .

[0044] In this embodiment, an MgO material layer is uniformly deposited on the inner wall surface of the input electrode 2 and the multiplication channel 3 by atomic layer deposition. MgO also has high secondary electron emission characteristics. When the primary electron energy is 600eV, its secondary electron emission coefficient can reach more than 7.2.

[0045] The output electrode 5 still uses a NiCr material layer, which is formed by thermal evaporation and is immersed to a depth of twice the channel aperture.

[0046] To verify the technical effect of this application, the finite integration method, Monte Carlo method, and Furman secondary electron emission model were used to analyze the performance of the sample provided in Example 1. Microchannel image intensifiers, traditional Glass-NiCr microchannel image intensifiers, with the inner wall of the channel being a bare lead silicate glass surface, and the input and output electrodes being NiCr, and all... The microchannel plate image intensifier is coated with microchannel plates, and the input electrode, output electrode, and inner wall of the channel are all coated with microchannel plates. The spatial resolution and gain were evaluated using simulation.

[0047] Spatial resolution was evaluated using the full width at half maximum (FWHM) of the electron speckle distribution on the fluorescent screen. A smaller FWHM indicates a more concentrated electron beam speckle and higher spatial resolution. Simulation results are shown below. Figure 2 As shown.

[0048] Figure 2 The results show that, under different output electrode immersion depths, this application... The speckle FWHM of the microchannel plate image intensifier is significantly smaller than that of the full-channel plate image intensifier. A microchannel plate image intensifier, slightly larger than a conventional Glass-NiCr microchannel plate image intensifier, was coated. This result demonstrates that using a NiCr material layer with a low secondary electron emission coefficient as the output electrode can effectively absorb large-angle electrons, collimate the output electron beam, and improve spatial resolution.

[0049] Gain simulation results are as follows Figure 3 As shown. Figure 3The results show that, under different output electrode immersion depths, the proposed method... The gain of the microchannel plate image intensifiers was significantly higher than that of the traditional Glass-NiCr microchannel plate image intensifiers, but lower than that of the full-channel plate image intensifiers. Coated microchannel plate image intensifier.

[0050] The results show that the input electrode and the inner wall of the multiplication channel use a high secondary electron emission coefficient. The material layer can significantly improve electron multiplication efficiency.

[0051] comprehensive Figure 2 , Figure 3 Simulation results show that the NiCr output electrode has the effect of improving spatial resolution. The input electrode and the inner wall of the multiplication channel both contribute to increasing the gain. Through their combined effect, the proposed gain... Microchannel plate image intensifiers can significantly improve spatial resolution while maintaining high gain levels, achieving synergistic optimization of gain and spatial resolution, and outputting high-brightness, high-definition two-dimensional images.

[0052] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only two embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible without substantially departing from the novel teachings and advantages of the subject matter described in this application. These modifications may include, for example, changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, the use of materials, colors, orientations, etc. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of this application. The order or sequence of any process or method steps may be changed or rearranged by alternative embodiments. Any "apparatus plus function" clause is intended to cover, and not only structurally equivalent but also equivalent structures, the structures performing the functions described herein. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of this application. Therefore, this application is not limited to a particular embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0053] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the best mode of performing this application as currently considered, or those features that are not relevant to implementing this application) may be omitted.

[0054] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, the development effort will be a routine task in design, manufacturing, and production without requiring extensive experimentation.

[0055] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A kind of possession The image intensifier of the microchannel plate is characterized by, include: Photocathode, Microchannel plates, fluorescent screens, photocathodes, The microchannel plate and the fluorescent screen are arranged sequentially from the top to the bottom of the image intensifier; The photocathode is used to receive incident light and generate an external photoelectric effect to complete photoelectric conversion; The The microchannel plates are arranged in the following order from the direction of electron propagation: A lead silicate glass substrate, wherein a plurality of electron multiplication channels are densely arranged in the substrate; The input electrode is located at the incident end of the electron multiplication channel, facing the photocathode; The output electrode is located at the emission end of the electron multiplication channel, facing the fluorescent screen; The inner wall of the channel forms the inner surface of the electron multiplication channel; The input electrode and the surface layer of the inner wall of the channel are Material layer; The surface layer of the output electrode is a NiCr material layer; The NiCr material layer is used to absorb electrons whose emission angle exceeds the threshold and to collimate the output electron beam.

2. A method possessing as described in claim 1 The image intensifier of the microchannel plate is characterized by: The input electrode and the Al2O3 material layer on the inner wall surface of the channel are formed by atomic layer deposition. The material layer is a continuous film layer uniformly vapor-deposited on the surface and inside the channel of a traditional microchannel plate.

3. A method possessing as described in claim 1 The image intensifier of the microchannel plate is characterized by: The NiCr material layer on the surface of the output electrode is formed by thermal evaporation on the already deposited electrode. At the output electrode of the microchannel plate in the material layer.

4. A method possessing as described in claim 3 The image intensifier of the microchannel plate is characterized by: The immersion depth of the NiCr material layer is determined by adjusting the evaporation source and the... The angle of the output surface of the microchannel plate is controlled; the larger the angle, the shallower the evaporation depth, and the smaller the angle, the deeper the evaporation depth.

5. A method possessing as described in claim 1 The image intensifier of the microchannel plate is characterized by: The material layer between the input electrode and the inner wall surface of the channel can be replaced with MgO material. The MgO material also possesses high secondary electron emission characteristics.

6. A method of possessing as described in claim 1 The image intensifier of the microchannel plate is characterized by: The The microchannel plates consist of one to three pieces. Two microchannel plates are stacked in a V-shape, and three microchannel plates are stacked in a Z-shape.

7. A method of possessing as described in claim 1 The image intensifier of the microchannel plate is characterized by: The photocathode is located at the top of the image intensifier and is used to convert incident photons into photoelectrons. The material is infrared Ag-O-Cs. The A microchannel plate, located directly below the photocathode, is used to multiply the photoelectrons; Fluorescent screen, located in the Directly below the microchannel plate, a fluorescent screen is used to convert the multiplied electrons into a visible light image; the screen is a P20-AF. The photocathode, the The microchannel plate and the fluorescent screen are arranged sequentially from the top to the bottom of the image intensifier.

8. A method of possessing as described in claim 7 The image intensifier of the microchannel plate is characterized by: The photocathode, the Both the microchannel plate and the fluorescent screen are circular in shape; The size of the photocathode is smaller than that of the The dimensions of the microchannel plate, the The size of the microchannel plate is smaller than the size of the fluorescent screen.

9. A method of possessing as described in claim 7 The image intensifier of the microchannel plate is characterized by: During operation, the photocathode, Microchannel plate input electrodes, The voltage applied to the output electrodes of the microchannel plate and the fluorescent screen increases gradually from low to high.

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