EBAPS asymmetric rectangular step cathode window alignment positioning racking clamp
By using asymmetric rectangular step cathode window alignment positioning rack fixtures in EBAPS devices, the problem of incomplete overlap between the photocathode effective area and the CMOS chip effective imaging area is solved, and the photocathode effective area is fully covered by the CMOS chip effective imaging plane, reducing short circuit risk and noise, and improving the imaging quality of the EBAPS device.
Patent Information
- Application Number
- CN202420623373.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-28
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-03-28
AI Technical Summary
During imaging, the existing EBAPS devices do not completely overlap the photocathode effective area and the CMOS chip effective imaging area, resulting in a "black frame" phenomenon in the imaging area, affecting the imaging quality, and the photocathode effective plane is too large and it is likely to cause short circuit or discharge, increasing noise.
The EBAPS asymmetric rectangular step cathode window alignment positioning rack fixture is adopted. Through the combination of coating fixtures, cathode hangers, mounting fixtures and tube and shell support seats, the photocathode effective surface fully covers the effective imaging surface of the CMOS chip, reduces the distance between the cathode window and the gold wire, reduces the risk of short circuit, and optimizes the coating boundary of the cathode window to reduce noise.
The effective photocathode surface fully covers the effective imaging surface of the CMOS chip, avoids the "black frame" phenomenon, reduces the risk of short circuit during operation of EBAPS devices, and reduces dark background noise, and improves imaging quality.
Smart Images
Figure CN222600904U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of novel low-light-level night vision imaging technology, and in particular to an EBAPS asymmetric rectangular step cathode window alignment and positioning mounting fixture. Background Art
[0002] EBAPS, or electron bombardment CMOS chip, is a new type of low-light-level night vision imaging device that combines low-light-level vacuum devices and semiconductor devices. This device replaces the fluorescent screen in the image intensifier tube with a CMOS chip. Under high vacuum conditions, through external photoelectric effect, the photoelectrons generated by the photocathode bombard the surface of the CMOS chip through an accelerating electric field to generate electron-hole pairs. The CMOS chip is connected to the external pins of the EBAPS through leads, and the movement is connected to the EBAPS pins. The target image with low noise and high resolution is obtained through the readout circuit.
[0003] Generally, the effective imaging surface of the CMOS chip is located in the middle of the CMOS chip, which is smaller than the surface of the CMOS chip. However, the center of the effective imaging surface of the CMOS chip does not coincide with the geometric center of the CMOS chip, while the geometric center of the CMOS chip coincides with the geometric center of the EBAPS shell. That is, the center of the effective imaging surface of the chip does not coincide with the geometric center of the shell, and the two center points are offset by a certain distance in the X and Y directions on the same horizontal plane.
[0004] In order to maximize the resolution of EBAPS, the distance from the photocathode to the surface of the CMOS chip needs to be reduced. The cathode window structure is generally designed as a step structure. The multi-alkali photocathode is grown on the small step surface of the cathode window by evaporation. The size of the step surface is basically equivalent to or slightly smaller than the size of the CMOS effective imaging surface. For ease of operation, a common practice is to lose a part of the CMOS effective pixel area and make the cathode effective area into a circle, which is inscribed in the effective imaging area of the CMOS chip.
[0005] As we all know, under the external photoelectric effect and the acceleration of the cathode high voltage, the photoelectrons generated by the EBAPS photocathode bombard the effective area of the CMOS chip to produce electron-hole pair imaging, where the overlapping part of the photocathode effective area and the chip effective imaging area is the imaging area of EBAPS.
[0006] Therefore, the existing circular cathode effective area solution cannot fully utilize the effective imaging area of the CMOS chip. When the EBAPS device is imaging, there is only an output image in the central circle. Around the effective imaging area of the CMOS chip, there is no output image because there is no electron bombardment in this area. A black frame is formed around it, which greatly affects the imaging quality and imaging effect.
[0007] On the contrary, Figure 1As shown, if the effective surface of the photocathode 3' is appropriately enlarged, the circle of the effective area of the photocathode 3' is circumscribed to the effective imaging area of the CMOS chip arranged in the CMOS chip ceramic base 4', that is, the effective surface of the photocathode 3' completely covers the effective surface of the CMOS chip, because the CMOS chip is interconnected with the pads on the chip ceramic through gold wires.
[0008] The highest point of the gold wire is about 0.05~0.2mm higher than the chip surface, and the distance from the effective surface of the photocathode to the gold wire will be smaller than the distance from the effective surface of the photocathode to the chip surface. This will cause a short circuit or discharge to easily occur between the photocathode and the gold wire when EBAPS is working, increasing the risk of device discharge.
[0009] In addition, under the premise that other conditions remain unchanged, the larger the effective surface of the photocathode, the greater the thermal noise generated by the cathode's own thermal emission, which will ultimately affect the imaging effect of the EBAPS device; and if the distance between the photocathode and the CMOS chip is too close and the effective surface of the photocathode is too large, there is a risk of interference between the cathode window and the chip ceramic base.
[0010] The prior art lacks a relevant fixture for reducing the area of the black edge region of EBAPS imaging when manufacturing EBAPS.
[0011] The information disclosed in the background technology section is only intended to increase the understanding of the overall background of the utility model, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to ordinary technicians in the field. Utility Model Content
[0012] In view of the above technical problems, the present application provides an EBAPS asymmetric rectangular step cathode window alignment and positioning fixture.
[0013] The present application provides an EBAPS asymmetric rectangular step cathode window alignment and positioning mounting fixture, including: a coating fixture, a cathode rack, a mounting fixture, and a tube shell support seat;
[0014] The cathode window of the photocathode is installed in the coating fixture;
[0015] The cathode hanger is connected to the cathode window through a mounting fixture; the cathode hanger and the cathode window are connected to the EBAPS tube shell through the Y-shaped groove and inner hole on the tube shell support seat.
[0016] Preferably, the coating fixture includes: a coating disk, a blind hole, a coating baffle, and a limiting boss; a plurality of blind holes are arranged on the coating disk at intervals; a coating baffle is arranged below the blind hole; the bottom of the coating baffle is connected to the bottom of the coating disk through a connecting rod; the cathode window is accommodated in the blind hole; and the limiting boss is arranged on one side of the coating baffle.
[0017] Preferably, the limiting bosses are arranged in pairs.
[0018] Preferably, the cathode rack includes: a large hole, a rack seat, a hook, a leaf spring, and a screw; a large hole is arranged on the top surface of the rack seat; a light hole on the cylindrical surface of the rack seat is connected to one end of the hook; the other end of the hook is connected to the robot for disassembly; a plurality of threaded holes are arranged at intervals on the cylindrical surface of the rack seat; a leaf spring and a screw.
[0019] Preferably, the cathode rack comprises: a plurality of leaf springs and a plurality of screws; and each threaded hole is tightened by the leaf springs and the screws to accommodate a cathode window disposed in the rack seat.
[0020] Preferably, the cathode rack comprises: a rack boss; the rack boss is arranged outside the rack seat, and the cathode rack and the mounting fixture are positioned by the rack boss.
[0021] Preferably, the mounting fixture comprises: a cylindrical block, an inner hole, a rectangular through groove, and a Y-shaped groove; an inner hole is provided on the top surface of the cylindrical block; a rectangular through groove is provided in a recessed central area of the inner hole; a Y-shaped groove is provided on the side wall of the inner hole; a cathode window is provided in the inner hole; a rectangular step of the cathode window is positioned and accommodated in the rectangular through groove; and the Y-shaped groove is positioned and connected with the bracket boss.
[0022] Preferably, the tube shell support seat includes: a cylindrical block, a larger inner hole, a smaller inner hole, a tube shell boss, and a notch; a larger inner hole and a smaller inner hole are provided on the top surface of the cylindrical block; a plurality of tube shell boss groups are arranged in the middle of the top surface of the cylindrical block, and a notch is arranged between adjacent tube shell boss groups; a vertical positioning surface is arranged in a depression in the middle of the cylindrical block; and a Y-shaped groove is arranged between the bosses in the tube shell boss group.
[0023] Preferably, the larger inner hole is positioned in cooperation with the outer circle of the cathode rack; and the smaller inner hole is positioned in cooperation with the cathode ring of the EBAPS shell.
[0024] The beneficial effects of this application include:
[0025] 1) The EBAPS asymmetric rectangular step cathode window alignment positioning mounting fixture provided in the present application, and the EBAPS device manufactured by using this set of fixtures can fully utilize the effective area of the CMOS chip, and the effective surface of the photocathode completely covers the effective imaging surface of the CMOS chip. The effective surface of the photocathode is approximately 0.1mm~0.4mm larger than the effective imaging surface of the CMOS chip, thereby avoiding the "black frame" phenomenon in part of the effective imaging surface of the CMOS chip, fully utilizing the effective surface of the CMOS chip, and reducing the effective surface of the photocathode, effectively reducing the probability of short circuit or discharge between the photocathode and the gold wire when the EBAPS is working, and reducing the dark background noise of the EBAPS device. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1The schematic diagram of the existing EBAPS structure is shown in FIG. 1 , wherein the EBAPS tube shell 1 ' comprises: a ceramic shell, a cathode ring, an indium tin alloy layer and pins; 2 ' is a cathode window, 3 ' is a photocathode, and 4 ' is a CMOS chip ceramic base comprising: a CMOS chip, ceramics and leads;
[0027] Figure 2 It is a three-dimensional schematic diagram of an existing asymmetric rectangular step cathode window;
[0028] Figure 3 It is a schematic diagram of the projection of the cathode window, the effective surface of the photocathode, and the effective imaging surface of the CMOS chip on the same horizontal plane in at least one embodiment provided by the present application, wherein the area surrounded by a, b, c, and d is the effective imaging area of the CMOS chip, the area surrounded by a1, b1, c1, and d1 is the ridge line where the asymmetric rectangular step surface of the cathode window intersects with the side surface, and the area surrounded by a2, b2, c2, and d2 is the effective surface of the photocathode (i.e., the boundary between the coated area and the non-coated area after coating). Assume that a>b>c>d, a1>b1>c1>d1, a2>b2>c2>d2, and a1>a2>a, b1>b2>b, c1>c2>c, d1>d2>d
[0029] Figure 4 is a schematic diagram of the effect of the photocathode being too large, too small or having no positioning fixture in at least one embodiment provided by the present application, wherein a is that the photocathode is larger than the effective imaging area of the chip, and due to the existence of the lead, the photocathode is close to the lead, which may cause discharge when the EBAPS device is working, b is that the effective area of the photocathode is a circle that inscribes the effective imaging area of the chip, so that the effective imaging surface of the chip is not fully utilized, and c is that the effective area of the photocathode is slightly larger than the effective imaging area of the chip, but because an alignment positioning fixture is not used, it may eventually cause a misalignment effect. In Figure b and Figure c, the dotted area is the CMOS chip imaging effective area, and the solid area is the photocathode effective area;
[0030] Figure 5 is a three-dimensional schematic diagram of a coating fixture in at least one embodiment provided in the present application;
[0031] Figure 6 is a three-dimensional schematic diagram of a cathode rack in at least one embodiment provided in the present application;
[0032] Figure 7 is a three-dimensional schematic diagram of a mounting fixture in at least one embodiment provided in the present application;
[0033] Figure 8 is a three-dimensional schematic diagram of a tube shell support seat in at least one embodiment provided in the present application;
[0034] Fig. 9In at least one embodiment of the present application, the EBAPS device is equipped with a core and a high voltage power supply in 2.6×10 -3 Imaging effect diagram under lx;
[0035] Legend:
[0036] Coating plate 11, blind hole 12, coating baffle 13, limiting boss 14, large hole 211, bracket seat 21, hook 22, leaf spring 23, screw 24, bracket boss 231, inner hole 31, rectangular through groove 32, Y-shaped groove 33, larger inner hole 41, smaller inner hole 42, tube shell boss 43, notch 44. DETAILED DESCRIPTION
[0037] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.
[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.
[0039] The technical means that are not described in detail in this application and are not used to solve the technical problems of this application are all set according to the common knowledge in the field, and can be implemented in a variety of common knowledge settings.
[0040] See also Figures 5 to 9 The EBAPS asymmetric rectangular step cathode window alignment positioning mounting fixture provided in this application, the CMOS chip ceramic base itself contains leads and pins, and the pins of the CMOS chip are matched with the corresponding holes of the EBAPS tube shell and connected to the pins outside the EBAPS.
[0041] In order to make full use of the effective imaging area of the chip, the present application designs the overall structure of the cathode window as a circular structure, and designs an asymmetric rectangular step on the cylinder, wherein the circular part is used for sealing with the EBAPS tube shell, and the asymmetric rectangular step corresponds to the effective imaging area of the CMOS chip. The upper surface of the asymmetric rectangular step is the growth surface of the photocathode, and the four side surfaces of the asymmetric rectangular step form an angle greater than 90 degrees with the step surface.
[0042] Reference Figure 2 , Figure 3 , the distances from the four boundaries of the effective imaging area of the CMOS chip to the geometric center of the CMOS are a, b, c, and d (abcd are unequal numbers), assuming a>b>c>d; the distances from the four edges of the upper surface of the corresponding cathode window rectangular step to the center of the circle are a1, b1, c1, and d1, assuming a1>b1>c1>d1; the distances from the rectangular boundary of the coating baffle of the coating fixture to the axis of the coating fixture hole (that is, the distance from the boundary of the cathode effective area to the axis) are a2, b2, c2, and d2, assuming a2>b2>c2>d2; and a1>a2>a, b1>b2>b, c1>c2>c, d1>d2>d.
[0043] Reference Figure 5 The coating fixture provided by the present application includes: a coating plate 11, a blind hole 12, a coating baffle 13, and a limiting boss 14; a plurality of blind holes 12 are provided at intervals on the coating plate 11; a coating baffle 13 is provided in the center area of the blind hole 12; and limiting bosses 14 are provided in pairs on one side wall of the coating baffle 13. The bottom of the limiting boss 14 is connected to the bottom of the coating plate 11 through a connecting rod.
[0044] In a specific embodiment, the coating fixture includes: 3 blind holes 12, which can be used to plate 3 cathode windows at a time. The cathode windows are installed in the blind holes 12, and the bottom surface of the blind holes 12 and the limiting bosses 14 are used to limit the radial movement of the cathode windows on the horizontal plane and the axial movement.
[0045] The coating baffle 13 is used to shield the non-coating area. After the film layer is coated around the cathode window using the fixture, a multi-alkali photocathode is produced by evaporation on the asymmetric rectangular step surface of the cathode window in the later stage. The multi-alkali photocathode grows on the entire rectangular step surface, and the area without coating in the early stage forms the effective area of the photocathode. The coating baffle 13 is fixedly installed below the blind hole 12 on the coating disk 11 by screws. Two limiting bosses 14 set on one side of the coating baffle 13 are used to locate the side of the asymmetric rectangular step with a distance a1 from the center (that is, the side farthest from the center). To effectively limit the horizontal rotation of the cathode window. After the cathode window is installed, its position in the coating fixture is unique and cannot be rotated. If it is installed in other positions, the cathode window can rotate a certain angle.
[0046] The coating baffle 13 is used to shield the corresponding area of the cathode window step surface from being coated. After the photocathode is manufactured and the cathode window is sealed with the EBAPS tube shell, this area is the effective area of the photocathode.
[0047] The cathode window is installed on the coating fixture, and the surface of the coating baffle 13 is 0.1 to 0.8 mm away from the step surface of the cathode window (i.e., the photocathode growth surface in the later process). The distances from the four edges of the baffle to the axis of the coating mounting hole are a2, b2, c2, and d2, respectively, where a2, b2, c2, and d2 are unequal numbers, assuming a2>b2>c2>d2.
[0048] Reference Figure 6 The cathode hanger includes: a hanger seat 21, a hook 22, a leaf spring 23, and a screw 24. The large hole 211 is used to match the outer circle of the cathode window. Four threaded holes are evenly distributed on the cylindrical surface of the cathode hanger. After matching with the corresponding leaf spring 23, the cathode window is tightened by screws. A light hole on the cylindrical surface is used to install and fix the hook 22. The hook 22 is mainly used for the manipulator to transfer the cathode hanger and the photocathode assembly. The hanger boss 231 on the cathode hanger is used for the positioning of the installation fixture when the cathode hanger and the cathode window are assembled, and the positioning of the cathode hanger assembly and the tube shell support seat when indium is sealed. Correspondingly, there are corresponding Y-shaped grooves 33 on the installation fixture and the tube shell support seat. The chamfer above the Y-shaped groove 33 plays a guiding role, and the groove below plays a positioning role.
[0049] Reference Figure 7 The mounting fixture is mainly used to position and mount the cathode window on the cathode rack, and is composed of an inner hole 31 that matches the cathode window, a rectangular through slot 32 that positions the rectangular step of the cathode window, and a Y-shaped slot 33. The inner hole 31 radially positions the cathode window in the horizontal plane, and the rectangular through slot 32 is used to limit the rotation of the cathode window in the horizontal plane and the movement in one axial direction by positioning the two relatively large oblique sides of the cathode window (i.e., the two sides of the rectangular step of the cathode window with a distance a1 and c1 from the center), and the Y-shaped slot 33 is used to position the rack boss 231 on the cathode rack, and the chamfer above the Y-shaped slot 33 plays a guiding role, and the slot below plays a positioning role.
[0050] For reference Figure 2 , Figure 6 , Figure 7 When installing the cathode window, first assemble the cathode window onto the mounting fixture, and install the cathode window onto the mounting fixture through a set of opposite sides of the inner hole 31 and the rectangular through groove 32 of the mounting fixture, with a unique position (the rectangular through groove is clamped by precise size control to clamp the two sides of the rectangular step of the cathode window with a distance a1 and c1 from the center); then install the cathode rack, with the cathode rack hook 22 facing upward, align the rectangular limiting boss 14 of the cathode rack with the Y-shaped groove 33 of the mounting fixture, and the larger inner hole 31 of the cathode rack 31 matches the outer circle of the cathode window. The relative position relationship between the cathode rack, the cathode window and the mounting fixture is unique, tighten the four screws on the cylindrical surface of the cathode rack to fix the cathode window on the cathode rack, and remove the mounting fixture to complete the installation of the cathode window on the cathode rack.
[0051] For reference Figure 8The shell support seat is a shaft-type part, which is mainly used to fix and support the EBAPS shell on the exhaust platform during cathode production. At the same time, when indium is sealed, the cathode bracket assembly and the EBAPS shell are used for positioning. The larger inner hole 41 on the top is used to cooperate with the outer circle of the cathode bracket for positioning, and the smaller inner hole 42 is used for the EBAPS shell cathode ring for positioning, which is used to limit the radial position in the horizontal direction and an axial position. A vertical positioning surface 411 in the shell support seat is used for positioning the pins on the back of the shell to limit the rotation of the shell in the shell support seat. After the EBAPS shell is assembled into the shell support seat, the EBAPS shell and the shell support seat have only one position relationship, cannot rotate, and have a unique position. The larger inner hole 41 in this application refers to a hole with a larger aperture than the smaller inner hole 42.
[0052] The four tube shell bosses 43 on the tube shell support seat are used to reduce the matching surface of the cathode bracket and the tube shell support seat when indium is sealed. The two 180° notches 44 symmetrically arranged on the ring body can facilitate the assembly of the tube shell. The chamfered parts above the four tube shell bosses 43 mainly play a guiding role for the cathode bracket and the cathode window when indium is sealed, so that the cathode bracket assembly can smoothly fall to the corresponding position of the EBAPS tube shell through the tube shell support seat. The Y-shaped groove 33 is used to position with the cathode bracket limiting boss 14 to ensure the uniqueness of the indium sealing position.
[0053] After indium sealing, the rectangular step coating boundary of the cathode window is the effective surface of the photocathode. The center of the effective surface coincides with the center of the effective surface of the CMOS chip. The effective surface of the photocathode is slightly larger than the effective surface of the CMOS chip, ensuring that the effective imaging surface of the CMOS is fully utilized.
[0054] Since the overall structure of the cathode window is a circular structure, and the effective imaging surface of the CMOS chip is an asymmetric rectangle relative to the axis of the tube shell, in order to make full use of the effective surface of the CMOS chip, it is necessary to ensure that the effective surface of the photocathode completely covers the effective surface of the CMOS chip (the rectangular side of the effective surface of the photocathode is about 0.1-0.4mm longer and wider than the corresponding rectangular side of the effective surface of the CMOS chip), and the closer the two are, the better. This requires precise control of the cathode window coating, cathode window assembly, tube shell assembly and indium sealing positioning in the early stage. The coating fixture ensures that the rectangular boundary of the coating meets the size requirements of the photocathode effective area after coating. By installing the fixture, the cathode window is assembled to the cathode bracket and its position is unique, and the coating boundary of the cathode window forms a certain angle with the rectangular boss of the cathode bracket. After the EBAPS tube shell is assembled to the tube shell support seat, the relative position of the tube shell and the EBAPS tube shell support seat is also unique, and the position of the chip forms a specific angle with the Y-shaped groove 33 on the tube shell support seat. Finally, during the indium sealing, positioning is performed through the outer circle of the cathode bracket assembly and the inner hole of the tube shell support seat, as well as through the boss on the cathode bracket assembly and the Y-shaped groove on the tube shell support seat, to ensure that the photocathode effective area and the chip effective area correspond one to one.
[0055] When the cathode is made, the EBAPS tube shell and the tube shell support seat are placed together in the corresponding position in the exhaust table, the cathode window and the cathode hanger assembly are placed above the antimony alkali seat alkali source and the antimony source in the exhaust table, and a multi-alkali photocathode is made on the rectangular step of the cathode window by evaporation. The multi-alkali photocathode grows on the entire rectangular step surface. After the photocathode is made, the cathode window and the cathode hanger assembly are transferred to the top of the EBAPS tube shell and the tube shell support seat by a robot in a vacuum state, and the cathode window assembly is slowly lowered and the cathode sealing (indium sealing) of the EBAPS is completed after the temperature drops to room temperature.
[0056] Comparative Example:
[0057] Comparative Example 1: Figure 1 This is a schematic diagram of the asymmetric rectangular step cathode window EBAPS structure, where 1 is the EBAPS shell, which consists of a ceramic shell, cathode ring, indium tin alloy and pins; 2 is the cathode window, 3 is the photocathode, and 4 is the CMOS chip ceramic base, which consists of a CMOS chip, ceramic and leads. The ceramic shell and cathode ring are soldered together, and the annular groove on the cathode ring contains indium tin alloy, which is used to seal the cathode window (including the photocathode) and the EBAPS shell; a multi-alkali photocathode is made on the rectangular step surface of the cathode window by evaporation under high vacuum conditions; the CMOS chip ceramic base purchases the 400BSI back-illuminated CMOS chip, a shelf product of Changchun Changguang Chenxin, and removes the protective glass cover on it. The pins of the CMOS chip match the corresponding holes of the EBAPS shell.
[0058] Reference Figure 1 , Figure 4 a. If the effective surface of the photocathode is too large, larger than the effective imaging area of the CMOS chip, due to the existence of the lead height, the photocathode is close to the lead, which may cause high-voltage discharge between the photocathode and the lead when the EBAPS device is working. Figure 1 It can be seen that since the purchased 400BSI back-illuminated CMOS chip itself contains a ceramic base and the surface of the CMOS chip is slightly lower than the ceramic base, if the distance between the photocathode and the CMOS chip is too close and the effective surface of the photocathode is too large, there is a risk of interference between the cathode window and the chip ceramic base.
[0059] Comparative Example 2: Reference Figure 4 b, is a circle with the effective imaging area of the chip inscribed in the effective area of the photocathode. The dotted rectangular line represents the effective imaging surface of the CMOS chip, and the solid circular line represents the effective surface of the photocathode. When the EBAPS device is imaged, only the solid circular line part is imaged, while the upper and lower parts within the rectangle outside the circle are non-imaging areas. It can be seen that the effective imaging surface of the CMOS chip is not fully utilized.
[0060] Comparative Example 3: Reference Figure 4c. Although the effective area of the photocathode is basically equivalent to the effective imaging area of the CMOS chip and slightly larger than the effective imaging area of the chip, because no alignment and positioning fixture is used, the matching part of the cathode window and the cathode ring of the EBAPS tube shell is circular, and the rectangular step of the cathode window is asymmetrical relative to the cathode window axis. Finally, after the cathode window is sealed, a similar phenomenon may occur. Figure 4 The photocathode effective area and the CMOS chip effective imaging area are misaligned in c. If this happens, the chip effective imaging area will not be fully utilized, and high voltage discharge may be generated between the photocathode and the lead when the EBAPS device is working. Figure 4 The dotted rectangular area in c is the effective imaging area of the CMOS chip, and the inclined solid rectangular area is the effective area of the photocathode. The imaging effect of the device obtained by using the clamp provided by the present application is as follows: Fig. 9 As shown, it is explained that the device obtained by using the fixture can achieve imaging.
[0061] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. An EBAPS asymmetric rectangular step cathode window alignment and positioning fixture, characterized in that: include: Coating fixture, cathode rack, installation fixture, tube shell support seat; The cathode window is installed in the coating fixture; The cathode hanger is connected with the cathode window through the installation fixture; the cathode hanger and the cathode window are connected with the EBAPS tube shell through the Y-shaped groove and the inner hole on the tube shell support seat.
2. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 1, characterized in that: The coating fixture includes: a coating plate, a blind hole, a coating baffle, and a limiting boss; a plurality of blind holes are arranged on the coating plate at intervals; a coating baffle is arranged below the blind hole; the bottom of the coating baffle is connected to the bottom of the coating plate through a connecting rod; the cathode window is accommodated in the blind hole; and the limiting boss is arranged on one side of the coating baffle.
3. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 2, characterized in that: The limiting bosses are arranged in pairs.
4. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 1, characterized in that: The cathode rack includes: a large hole, a rack seat, a hook, a leaf spring, and a screw; the large hole is arranged on the top surface of the rack seat; the light hole on the cylindrical surface of the rack seat is connected to one end of the hook; the other end of the hook is connected to the manipulator; a plurality of threaded holes, leaf springs, and screws are arranged at intervals on the cylindrical surface of the rack seat.
5. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 4, characterized in that: The cathode rack comprises: a plurality of leaf springs and a plurality of screws; and each threaded hole is tightened by the leaf springs and the screws to accommodate a cathode window arranged in the rack seat.
6. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 4, characterized in that: The cathode rack comprises: a rack boss; the rack boss is arranged outside the rack seat, and the cathode rack and the mounting fixture are positioned by the rack boss.
7. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 4, characterized in that: The mounting fixture includes: a cylindrical block, an inner hole, a rectangular through groove, and a Y-shaped groove; the inner hole is provided on the top surface of the cylindrical block; a rectangular through groove is provided in a recessed manner in the central area of the inner hole; a Y-shaped groove is provided on the side wall of the inner hole; a cathode window is provided in the inner hole; a rectangular step of the cathode window is positioned and accommodated in the rectangular through groove; and the Y-shaped groove is positioned and connected with the bracket boss.
8. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 1, characterized in that: The tube shell support seat includes: a cylindrical block, a larger inner hole, a smaller inner hole, a tube shell boss, and a notch; a larger inner hole and a smaller inner hole are provided on the top surface of the cylindrical block; a plurality of tube shell boss groups are arranged in the middle of the top surface of the cylindrical block, and a notch is arranged between adjacent tube shell boss groups; a vertical positioning surface is arranged in a depression in the middle of the cylindrical block; and a Y-shaped groove is arranged between the bosses in the tube shell boss group.
9. The EBAPS asymmetric rectangular step cathode window alignment and positioning fixture according to claim 8, characterized in that: The larger inner hole is matched with the outer circle of the cathode rack for positioning; the smaller inner hole is matched with the cathode ring of the EBAPS shell for positioning.