Structure for improving sensitivity of EBAPS cathode and EBAPS device thereof
By setting an inverted pyramid array microstructure and a diffraction material layer on the cathode lens of the EBAPS device, combined with a composite metal film, the conductivity and light absorption of the photocathode are enhanced, solving the problem of low photocathode sensitivity in EBAPS devices and achieving higher sensitivity and imaging quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTH NIGHT VISION TECH
- Filing Date
- 2025-12-25
- Publication Date
- 2026-05-01
AI Technical Summary
The photocathode sensitivity of existing EBAPS devices is low, resulting in low signal-to-noise ratio and resolution, making it difficult to meet imaging requirements.
A cathode lens with an inverted pyramid array microstructure is used, combined with a filling diffraction material layer, a composite metal conductive film, and a sealing film to enhance the conductivity and light absorption of the photocathode. The absorption rate of light at the photocathode is improved through multiple reflections and total internal reflection.
The sensitivity of the EBAPS device has been improved to 800~1000μA/lm, which significantly improves the imaging effect, reduces noise, and enhances the signal-to-noise ratio and resolution.
Smart Images
Figure CN121964470A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of EBAPS device technology, and in particular to a structure for improving the sensitivity of an EBAPS cathode and an EBAPS device thereof. Background Technology
[0002] EBAPS (Electron Impact Active Pixel CMOS) is a novel low-light night vision imaging device that combines a low-light vacuum device with a semiconductor device. EBAPS replaces the microchannel plate and phosphor screen in the image intensifier with a CMOS chip. The cathode ring and ceramic substrate are brazed to form the EBAPS housing, and the CMOS chip is soldered inside the housing. An annular groove is formed inside the cathode ring, filled with indium tin alloy. Heating and melting the indium tin alloy completes indium indium filling. A composite metal film is deposited on the cathode lens for optical opening and conductivity. Another composite metal film is deposited on the outside of the cathode lens for vacuum sealing between the cathode lens and the ceramic substrate after the photocathode is fabricated.
[0003] EBAPS features low readout noise and high resolution, making it particularly suitable for video imaging in extremely low-light conditions. Furthermore, systems using EBAPS offer advantages such as all-weather operation, small size, light weight, and a wide dynamic range. Due to its strong low-light capability, high resolution, ability to better distinguish target details, and ability to enable window-like observation, EBAPS is widely used.
[0004] Testing revealed that the sensitivity of multiple batches of EBAPS photocathodes was 300~500μA / lm, which differed significantly from the theoretical calculation value. Due to the low sensitivity, the signal-to-noise ratio and resolution of the multi-alkali photocathode EBAPS devices were also low, resulting in a lot of noise in the image and making it difficult to meet the usage requirements.
[0005] The information disclosed in the background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention
[0006] This application addresses the aforementioned technical problems by providing a structure and EBAPS device for improving the sensitivity of the EBAPS cathode. It employs a cathode lens with an inverted pyramid array microstructure, which has multiple structural options that facilitate the sealing of the vacuum cavity and ensure the excellent conductivity of the photocathode.
[0007] This application provides a structure for improving the sensitivity of EBAPS cathodes, including: a cathode lens, an inverted pyramid micro / nano array structure, a layer of diffractive material, a composite metal conductive film, a composite metal sealing film, and a photocathode; An inverted pyramid micro / nano array structure is set on one side of the cathode lens; a layer of diffraction material is set on the inverted pyramid micro / nano array structure. A composite metal conductive film is disposed on the top surface of the filling diffraction material layer near the periphery; a composite metal sealing film is disposed on the top surface of the composite metal conductive film near the periphery. The photocathode is covered and disposed in the central region of the filling diffraction material layer and overlapped on the composite metal conductive film; The input light passes through the cathode lens to reach the inverted pyramid micro-nano array structure. The incident near-infrared light undergoes multiple reflections and refractions in the inverted pyramid micro-nano array structure, making the light entering the photocathode film layer oblique light. After total internal reflection, the oblique light is reflected back to the photocathode to form total internal reflection light.
[0008] Preferably, a protrusion is provided in the central region of the cathode lens; an inverted pyramid micro / nano array structure is disposed on the protrusion; and a layer of diffraction material is disposed on the inverted pyramid micro / nano array structure. The composite metal conductive film is applied to the periphery, sidewalls, sidewalls of the protrusion, and outer periphery of the protrusion of the cathode lens of the filling diffraction material layer.
[0009] Preferably, the overlap between the photocathode and the composite metal conductive film is 10% to 15% of the size of the photocathode.
[0010] Preferably, the composite metal sealing film is 20% to 35% of the size of the photocathode.
[0011] Preferably, a conical surface of 110° to 130° is provided on the side of the boss.
[0012] Preferably, the preparation method includes the following steps: 1) An inverted pyramid micro-nano array structure is fabricated on one side surface of the cathode lens, and a layer of diffraction material is placed on the inverted pyramid micro-nano array structure for planarization. 2) Clean the surface of the cathode lens on the side of the inverted pyramid micro / nano array structure; 3) A patterned composite metal film is deposited as a conductive film in a coating machine using a mask. The composite metal film is placed on the periphery of the top surface of the diffraction material layer. 4) Using another mask in the coating machine, deposit another patterned composite metal sealing film as a sealing film on the top surface of the composite metal film layer near the periphery; 5) A photocathode is fabricated in a high vacuum chamber. The photocathode is placed in the central region of the device and covers the top surface of the diffraction material layer. It overlaps the composite metal conductive film near the periphery and top surface of the diffraction material layer. The top surface of the photocathode is flush with the top surface of the composite metal sealing film. At 120~150℃, an indium tin alloy and a ceramic base tube shell are used to complete the sealing at the sealing film position.
[0013] Preferably, the filler material used for the diffraction material layer is selected from any one of Al2O3, TiO2, and Ta2O5.
[0014] Preferably, the material of the composite metal film is selected from at least one of Cr, Ti, Cu, Ag, and Au.
[0015] Preferably, a composite metal sealing film is used as the sealing film, and the sealing film material is selected from at least one of Cr, Ti, Ni, Cu, Ag, and Au.
[0016] Another aspect of this application provides an EBAPS device, including: the structure for improving the sensitivity of the EBAPS cathode as described above; the structure for improving the sensitivity of the EBAPS cathode is disposed in the cathode of the EBAPS device.
[0017] The beneficial effects that this application can produce include: 1) The structure provided in this application for improving the sensitivity of EBAPS photocathodes addresses the problem of low sensitivity in existing EBAPS photocathodes by setting an inverted pyramid micro / nano array structure within the diffractive material layer, thereby improving the sensitivity and conductivity of the EBAPS photocathode and enhancing the EBAPS electron imaging effect. Testing shows that the sensitivity of the EBAPS device has increased from an average of 500 μA / lm to 800~1000 μA / lm. The detail resolution of the electron imaging image of the EBAPS device is significantly improved, and the reduced noise leads to an improved signal-to-noise ratio, greatly enhancing the imaging effect of the EBAPS device. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the inverted pyramid micro / nano array structure in operation. Figure 2 This is a schematic diagram of the inverted pyramid micro / nano array structure cathode lens of the present invention. Figure 3 This is a schematic diagram of another inverted pyramid micro / nano array structure cathode lens of the present invention; Figure 4 These are the imaging images obtained in Embodiment 1 and Comparative Example 1 of this application. Wherein a represents Embodiment 1; b represents Comparative Example 1; Legend: 1 is the incident light, 2 is the emitted electron, 3 is the cathode lens, 4 is the inverted pyramid micro / nano array structure, 5 is the oblique light, 6 is the reflected light, 7 is the photocathode, 23 is the filling diffraction material layer, 24 is the composite metal conductive film, and 25 is the composite metal sealing film. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0021] Technical means not detailed in this application and not used to solve the technical problems of this application are all set according to common general knowledge in the field, and multiple common general knowledge setting methods can be implemented.
[0022] See Figures 1-3 The EBAPS cathode sensitivity enhancement method provided in this application includes a cathode lens 3 comprising a cathode lens 3 and an inverted pyramid micro / nano array structure 4. The cathode lens 3 provides support, while the inverted pyramid micro / nano array structure 4 effectively enhances the sensitivity of the device and simultaneously achieves anti-reflection, light trapping, and absorption enhancement of near-infrared incident light.
[0023] The input light beam passes through the cathode lens 3 and reaches the inverted pyramid micro / nano array structure 4. Because the inclined surfaces of each inverted pyramid in the micro / nano array structure 4 cause multiple reflections and refractions of the incident near-infrared light, the light entering the film layer of the photocathode 7 becomes oblique light. When the oblique light reaches the vacuum interface of the photocathode 7, it undergoes total internal reflection due to the required angle, causing the light to be reflected back to the photocathode 7, forming a total internal reflection beam. This increases the optical path length of the incident light inside the photocathode 7 by at least two times, thus increasing the absorption rate of the incident light beam 1 and improving the sensitivity of the multi-alkali photocathode 7. (See appendix) Figure 1 .
[0024] For the cathode lens 3 of the inverted pyramid micro-nano array structure 4, a cathode lens 3 with a planar structure is designed, which is beneficial for sealing the vacuum cavity and ensuring the conductivity of the photocathode lens and the photocathode.
[0025] In one specific embodiment, the structural design and manufacturing process is as follows: (see attached document) Figure 2 .
[0026] 1) A full-surface inverted pyramid micro-nano array structure 4 is fabricated on one side surface of the cathode lens 3. A planarization treatment is performed on the inverted pyramid micro-nano array structure 4 by setting a filling diffraction material layer 23. The filling material used for the filling diffraction material layer 23 is selected from Al2O3, TiO2, and Ta2O5. 2) Clean the surface of the cathode lens 3 on both sides of the inverted pyramid micro / nano array structure; 3) A patterned composite metal film 41 is deposited as a conductive film in a coating machine using a mask. The composite metal film 41 is disposed on the periphery of the top surface of the filling diffraction material layer 23. The conductive film material is selected from at least one of Cr, Ti, Cu, Ag and Au. 4) Using another mask in a coating machine, deposit another patterned composite metal sealing film 25 as a sealing film on the top surface of the composite metal film layer 41 near the periphery. The sealing film material is selected from at least one of Cr, Ti, Ni, Cu, Ag, and Au. 5) A photocathode 7 is fabricated in a high vacuum cavity. The photocathode 7 is located in the central region of the device and covers the top surface of the filling diffraction material layer 23. It overlaps the periphery and top surface of the composite metal conductive film 24 near the filling diffraction material layer 23. The top surface of the photocathode 7 is flush with the top surface of the composite metal sealing film 25. The sealing is completed at the sealing film position using an indium tin alloy and a ceramic base tube shell at 120~150℃.
[0027] In one specific embodiment, the overlap between the photocathode 7 and the conductive film 24 is 10% to 15% of the size of the photocathode 7; In one specific embodiment, the sealing film 25 is 20% to 35% of the size of the photocathode 7.
[0028] In one specific embodiment, the EBAPS device, taking into account factors such as its critical distance control, fabricates a photocathode 7 on the boss structure, such as... Figure 3 This ensures that the surface of the photocathode 7 has a better finish during the manufacturing process.
[0029] A boss structure is adopted. To prevent the conductive film and photocathode 7 from breaking at the step after fabrication due to excessive step height, resulting in an open circuit, a 110°~130° conical surface needs to be set on the side of the boss to ensure smooth connection of the multilayer film on the side of the step. See appendix. Figure 3 .
[0030] Another aspect of this application provides an EBAPS device, including: the structure for improving the sensitivity of the EBAPS cathode as described above; the structure for improving the sensitivity of the EBAPS cathode is disposed in the cathode of the EBAPS device.
[0031] Unless otherwise specified, all materials and instruments used in the following embodiments were obtained through commercial channels; and all detection methods used are existing methods unless otherwise specified.
[0032] Example 1 The method provided in this application yields, as follows: Figure 2 The inverted pyramid micro-nano array structure cathode lens is shown.
[0033] Comparative Example 1 The difference from Example 1 is that the inverted pyramid micro / nano array structure 4 was not set, resulting in a cathode lens.
[0034] After fabricating EBAPS devices using the cathode lenses obtained in Example 1 and Comparative Example 1 according to existing methods, the electronic imaging effect is as follows: Figure 4 As shown, through testing, the sensitivity of the EBAPS device was improved from an average of 500 μA / lm (Comparative Example 1) to 800~1000 μA / lm (Example 1).
[0035] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A structure for improving the sensitivity of EBAPS cathodes, characterized in that, include: Cathode lens (3), inverted pyramid micro-nano array structure (4), filled diffraction material layer (23), composite metal conductive film (24), composite metal sealing film (25), photocathode (7); An inverted pyramid micro-nano array structure (4) is provided on one side of the cathode lens (3); a layer of diffraction material (23) is provided on the inverted pyramid micro-nano array structure (4); A composite metal conductive film (24) is disposed on the top surface of the filling diffraction material layer (23) near the periphery; a composite metal sealing film (25) is disposed on the top surface of the composite metal conductive film (24) near the periphery. The photocathode (7) is disposed in the central region of the filling diffraction material layer (23) and overlapped on the composite metal conductive film (24); The input light passes through the cathode lens (3) and reaches the inverted pyramid micro-nano array structure (4). The incident near-infrared light undergoes multiple reflections and refractions in the inverted pyramid micro-nano array structure (4), making the light entering the film layer of the photocathode (7) oblique light. After the oblique light undergoes total internal reflection, the light is reflected back to the photocathode (7) to form total internal reflection light.
2. The structure for improving the sensitivity of EBAPS cathodes according to claim 1, characterized in that, A protrusion is provided in the central region of the cathode lens (3); an inverted pyramid micro-nano array structure (4) is provided on the protrusion; a layer of diffraction material (23) is provided on the inverted pyramid micro-nano array structure (4); The composite metal conductive film (24) is applied to the periphery, sidewall, boss sidewall, and outer periphery of the boss of the cathode lens (3) filled with diffraction material layer (23).
3. The structure for improving the sensitivity of EBAPS cathodes according to claim 1, characterized in that, The overlap between the photocathode (7) and the composite metal conductive film (24) is 10% to 15% of the size of the photocathode (7).
4. The structure for improving the sensitivity of EBAPS cathodes according to claim 1, characterized in that, The composite metal sealing film (25) is 20% to 35% of the size of the photocathode (7).
5. The structure for improving the sensitivity of EBAPS cathodes according to claim 2, characterized in that, The side of the boss is provided with a conical surface of 110°~130°.
6. The structure for improving the sensitivity of EBAPS cathodes according to claim 1, characterized in that, The preparation method includes the following steps: 1) An inverted pyramid micro-nano array structure (4) is fabricated on one side surface of the cathode lens (3), and a layer of diffraction material (23) is set on the inverted pyramid micro-nano array structure (4) for planarization. 2) Clean the surface of the cathode lens (3) on the side of the inverted pyramid micro / nano array structure (4); 3) A patterned composite metal film (41) is deposited in a coating machine using a mask as a conductive film. The composite metal film (41) is disposed on the periphery of the top surface of the filling diffraction material layer (23). 4) Using another mask in the coating machine, deposit another patterned composite metal sealing film (25) as a sealing film on the top surface of the composite metal film layer (41) near the periphery; 5) A photocathode (7) is fabricated in a high vacuum cavity. The photocathode (7) is located in the central region of the device and covers the top surface of the filling diffraction material layer (23). It overlaps the composite metal conductive film (24) near the periphery and top surface of the filling diffraction material layer (23). The top surface of the photocathode (7) is flush with the top surface of the composite metal sealing film (25). At 120~150℃, an indium tin alloy and a ceramic base tube shell are used to complete the sealing at the sealing film position.
7. The structure for improving the sensitivity of EBAPS cathodes according to claim 6, characterized in that, The filling material used in the filling diffraction material layer (23) is selected from any one of Al2O3, TiO2, and Ta2O5.
8. The structure for improving the sensitivity of EBAPS cathodes according to claim 6, characterized in that, The material of the composite metal film (41) is selected from at least one of Cr, Ti, Cu, Ag and Au.
9. The structure for improving the sensitivity of EBAPS cathodes according to claim 6, characterized in that, The composite metal sealing membrane (25) is used as the sealing membrane, and the sealing membrane material is selected from at least one of Cr, Ti, Ni, Cu, Ag and Au.
10. An EBAPS device, characterized in that, include: The structure for improving the sensitivity of the EBAPS cathode as described in any one of claims 1 to 9; The structural configuration used to improve the sensitivity of the EBAPS cathode is incorporated into the cathode of the EBAPS device.