A cryogenic seamless stitching focal plane applied to a space-based all-coverage remote sensing camera

Abstract

The present invention provides an infrared focal plane assembly for a geosynchronous remote sensing satellite. Based on an integrated cold management technology, through a seamless splicing method, the ability of space-based all-region detection is achieved. The infrared focal plane assembly includes 4 spliced detector sub-assemblies. Each spliced detector sub-assembly adopts a modular design and an integrated cold management technology to splice multiple detector single modules into a modular detector unit, and then performs optical splicing through the spliced detector sub-assemblies. This focal plane assembly can be applied to fields such as space-based infrared remote sensing, and is particularly suitable for a geosynchronous earth observation satellite system of the staring type.

Description

Technical Field

[0001] The present invention relates to a cryogenic seamless mosaic focal plane applied to a space-based all-region coverage remote sensing camera, and belongs to the field of aerospace optical remote sensing technology. Background Art

[0002] Ultra-large-scale mosaic infrared focal planes are used in spaceborne large field-of-view and high-resolution earth exploration scenarios. They are an important part of future military warning and reconnaissance infrared optical cameras and also a bottleneck technology for developing the next generation of high-performance infrared optical cameras.

[0003] The mainstream product of the existing detector single module size is 2.7k×2.7k, and 4k×4k scale detector single modules will be gradually applied in the future. Considering the optical system design, even using 4k devices cannot meet the detection requirements. Therefore, using detector single module mosaics for the focal plane assembly is still an important engineering implementation method. The main ways of detector array mosaics are optical mosaic and mechanical mosaic +

[0004] There are two ways. Limited by the device structure, the pure mechanical mosaic method cannot completely eliminate the seam. The hybrid mosaic method is an inevitable implementation approach. In addition to the mosaic form, for infrared focal plane assemblies, especially ultra-large-scale mosaic detector arrays, their technical routes are also the core links of engineering implementation. Space-based high-performance infrared detectors generally need to work in a temperature range of 100K or even lower. After the detectors are mosaicked into a focal plane assembly, items such as volume, power consumption, weight, and ground maintainability must be designed and evaluated.

[0005] Chinese invention patent CN 108593107 A discloses a mosaic structure of a wide-field wide-coverage detection system based on dual lenses and area array mosaics, which uses the form of dual-lens optical mosaic + mechanical mosaic, and the detectors are mosaicked in a "pin" shape. However, it does not achieve all-region coverage and seamless mosaic. Chinese invention patent CN 106813781 A discloses an ultra-large area composite mosaic of an infrared detector, which uses a bidirectional staggered mosaic method to effectively eliminate the seam size, but there is still an uncovered area of 0.14%, and it cannot meet the requirements of the new generation of equipment. Chinese invention patent CN113514150A discloses a modular three-dimensional adjustable detector mosaic structure, which uses a detector single module as a mosaic module, and each detector single module is provided with a cold chain interface and a cable interface. This structure has some disadvantages, such as the refrigeration reliability of multiple cold chains, the increase in power consumption caused by heat leakage of multiple cables, and the need for a larger volume to ensure the installation of all interfaces. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art and provide a cryogenic seamless mosaic focal plane for a space-based all-coverage remote sensing camera, ensuring good maintainability of the mosaic detector sub-assembly and ensuring the temperature uniformity and stability of the detector array.

[0007] The technical solution of the present invention is:

[0008] The present invention discloses a cryogenic seamless mosaic focal plane for a space-based all-coverage remote sensing camera, including: 4 mosaic detector sub-assemblies, respectively located in the four quadrants under the satellite coordinate system, optically mosaicked with each other to achieve a large-scale focal plane without seams; among them, each mosaic detector sub-assembly includes a number of modular mosaic units, and a number of modular mosaic units form a detector array. When projecting the satellite coordinate system onto the earth coordinate system, the modular mosaic units of each mosaic detector sub-assembly are staggered and covered by the mosaic composite splicing method to eliminate the optical seams between the mosaic detector sub-assemblies and achieve space-based all-coverage detection; the mosaic detector sub-assembly uses a multi-temperature zone thermal control design method for thermal control to reduce the temperature fluctuation of the detector array and ensure temperature stability.

[0009] In the above seamless mosaic focal plane, the mosaic composite splicing method is specifically: each detector sub-assembly is mechanically spliced in a mosaic form, and the adjacent detector single modules in all mosaic detector sub-assemblies overlap 5 to 15 rows of pixels.

[0010] In the above seamless mosaic focal plane, the mosaic detector sub-assembly further includes a mosaic frame, a support assembly, a support flange, a radiation shield, and a cooler hot-end radiator; a number of modular mosaic units are thermally installed on the mosaic frame, and the mosaic frame is thermally insulated and installed on the support flange through the support assembly; the radiation shield is arranged around the detector array and is thermally insulated and installed on the support flange; the cooler hot-end radiator is installed on the support flange to cool the detector array.

[0011] In the above seamless mosaic focal plane, the cooler hot-end radiator includes a cold finger, a topological cold plate, a first flexible cold chain, and a second flexible cold chain. The cold finger and the topological cold plate are installed on the mosaic frame. The first flexible cold chain is on the modular mosaic unit, and the second flexible cold chain is installed on the outer side wall of the radiation shield.

[0012] In the above-mentioned seamless splicing focal plane, the modular detector unit includes a single detector module, a modular splicing substrate and an electrical flexible board; several single detector modules are installed on the modular splicing substrate, and a low-temperature circuit is provided on the modular splicing substrate, and the single detector module is bonded to the low-temperature circuit on the modular splicing substrate; the electronic signals of several single detector modules on the same modular splicing substrate are merged and led out to the electrical flexible board; and an installation interface for a first flexible cold chain and an electrical flexible board is provided on the modular splicing substrate.

[0013] In the above seamlessly spliced ​​focal plane, the multi-temperature zone thermal control design method is specifically as follows:

[0014] Divide the spliced ​​detector subassembly into a plurality of temperature zones, the temperature zones comprising a detection temperature zone, a cold shield temperature zone and a low-temperature optical temperature zone; the detection temperature zone is arranged inside the cold shield temperature zone, and the cold shield temperature zone is arranged inside the low-temperature optical temperature zone;

[0015] The modular splicing unit and splicing frame work in the detection temperature zone, using cold fingers, topological cold plates, and the first flexible cold chain for refrigeration;

[0016] The radiation shield works in the cold shield temperature zone; the cold shield temperature zone uses cold fingers, topological cold plates, and the second flexible cold chain for cooling;

[0017] The supporting flange and the hot end heat sink operate in the low temperature optical temperature zone.

[0018] In the above seamlessly spliced ​​focal plane, the operating temperature of the detector single module is 90-100K, and the operating temperature of the spliced ​​detector subassembly is 200-220K.

[0019] In the above seamlessly stitched focal plane, the stitched detector subassembly is mounted on the camera via a supporting flange, and the cold finger is mounted on the supporting flange via a hot end heat sink.

[0020] In the above-mentioned seamless splicing focal plane, the first flexible cold chain is designed as a primary backup.

[0021] In the above-mentioned seamless stitching focal plane, the temperature of the low-temperature optical temperature zone is 200-220K, the temperature of the cold screen temperature zone is 120-140K, and the temperature of the detection temperature zone is 80-110K.

[0022] The beneficial effects of the present invention and the prior art are:

[0023] (1) The present invention adopts a mosaic composite splicing method to achieve ultra-large-scale seamless splicing of focal planes, which can meet the "seamless airspace" detection requirements of the new generation of earth observation satellites.

[0024] (2) The present invention adopts a modular detector unit F9 design, effectively reducing the number of flexible printed circuit boards F18, and ensuring that the spliced detector sub-assembly has good maintainability.

[0025] (3) The present invention adopts a multi-temperature zone thermal control scheme for the spliced detector sub-assembly based on an integrated cold management technology, ensuring the temperature uniformity and stability of the detector array. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the infrared focal plane assembly of the present invention;

[0027] Figure 2 is a schematic diagram of the implementation of 9×9 splicing with a 2.7k×2.7k detector single module of the present invention. Figure (a) is the splicing method in the earth coordinate system, and Figure (b) is the layout diagram of the spliced detector sub-assembly in the satellite coordinate system;

[0028] Figure 3 is a block diagram of the integrated cold management implementation scheme of the spliced detector sub-assembly of the present invention;

[0029] Figure 4 is a model diagram of the modular detector unit A of the present invention;

[0030] Figure 5 is a model diagram of the spliced detector sub-assembly C of the present invention;

[0031] Figure 6 is a layout diagram of the modular detector units of the spliced detector sub-assembly C and the spliced detector sub-assembly D of the present invention.

[0032] Figure 7 is a schematic diagram of the N×N ultra-large-scale splicing of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following further describes the present invention in detail with reference to the drawings and specific embodiments.

[0034] As Figure 1As shown, the present invention discloses a cryogenic seamless splicing focal plane applied to a space-based all-region coverage remote sensing camera, including: 4 splicing detector sub-assemblies; the 4 splicing detector sub-assemblies are respectively located in four quadrants under the satellite coordinate system and are optically spliced with each other; the splicing detector sub-assembly includes a number of modular splicing units F9, and a number of modular splicing units F9 form a detector array. When the satellite coordinate system is projected onto the earth coordinate system, the modular splicing units F9 of each splicing detector sub-assembly are staggered and covered by the mosaic composite splicing method, eliminating the optical splicing seams between the splicing detector sub-assemblies, realizing space-based all-region coverage detection. The splicing detector sub-assembly adopts a multi-temperature zone thermal control design method for thermal control, reducing the temperature fluctuation of the detector array and ensuring temperature stability; the 4 splicing detector sub-assemblies realize a large-scale focal plane without splicing seams.

[0035] The mosaic composite splicing method is specifically as follows: each detector sub-assembly is mechanically spliced in a mosaic form, and the adjacent detector single modules in all the splicing detector sub-assemblies overlap by 5 to 15 rows of pixels.

[0036] The splicing detector sub-assembly further includes a splicing frame F11, a support assembly F17, a support flange F16, a radiation shield F20, and a cooler hot-end radiator F14; a number of modular splicing units F9 are thermally installed on the splicing frame F11, and the splicing frame F11 is thermally insulated and installed on the support flange F16 through the support assembly F17; the radiation shield F20 is arranged around the detector array and is thermally insulated and installed on the support flange F16; the cooler hot-end radiator F14 is installed on the support flange F16 to cool the detector array. The splicing detector sub-assembly is installed on the camera through the support flange F16, and the cold finger F13 is installed on the support flange F16 through the hot-end radiator F14. The first flexible cold chain F10 is designed with a main and backup structure.

[0037] The cooler hot-end radiator F14 includes a cold finger F13, a topological cold plate F12, a first flexible cold chain F10, and a second flexible cold chain F15. The cold finger F13 and the topological cold plate F12 are installed on the splicing frame F11. The first flexible cold chain F10 is on the modular splicing unit F9, and the second flexible cold chain F15 is installed on the outer side wall of the radiation shield F20.

[0038] The modular detector unit F9 includes a detector single module F8, a modular splicing substrate F27, and an electrical flexible board F18. A number of detector single modules F8 are installed on the modular splicing substrate F27. A cryogenic circuit F19 is provided on the modular splicing substrate F27 to bond the detector single module F8 to the cryogenic circuit F19 on the modular splicing substrate F27. The electronic signals of a number of detector single modules F8 on the same modular splicing substrate F27 are combined and led out to the electrical flexible board F18. An installation interface for the first flexible cold chain F10 and the electrical flexible board F18 is provided on the modular splicing substrate F27.

[0039] The multi-temperature zone thermal control design method is specifically as follows:

[0040] The spliced detector sub-assembly is divided into multiple temperature zones, and the temperature zones include a detection temperature zone, a cold shield temperature zone, and a cryogenic optical temperature zone. The detection temperature zone is arranged inside the cold shield temperature zone, and the cold shield temperature zone is arranged inside the cryogenic optical temperature zone;

[0041] The modular splicing unit F9 and the splicing frame F11 operate in the detection temperature zone and are cooled by using a cold finger F13, a topological cold plate F12, and a first flexible cold chain F10;

[0042] The radiation shield F20 operates in the cold shield temperature zone. The cold shield temperature zone is cooled by using a cold finger F13, a topological cold plate F12, and a second flexible cold chain F15;

[0043] The support flange F16 and the hot end radiator F14 operate in the cryogenic optical temperature zone F5.

[0044] Other components operate across temperature zones, and the thermal resistance is designed to control heat transfer and heat leakage.

[0045] According to the design of different temperature zones, the installation of each component is carried out in a heat-conducting or heat-insulating manner.

[0046] The temperature of the cryogenic optical temperature zone F5 is 200 - 220K, the temperature of the cold shield temperature zone F6 is 120 - 140K, and the temperature of the detection temperature zone F7 is 80 - 110K.

[0047] Through the design of the distribution method and thermal resistance of the flexible cold chain, the comprehensive cold management of multiple temperature zones and the uniform cooling of the detector array are realized. Through the design of 3 temperature zones, the temperature fluctuation of the detector array is reduced to ensure its temperature stability.

[0048] The operating temperature of the detector single module F8 is 90 - 100K, and the operating temperature of the spliced detector sub-assembly is 200 - 220K.

[0049] Embodiment

[0050] Such as Figure 7As shown in the figure, a low-temperature seamless splicing focal plane applied to a space-based all-coverage infrared remote sensing camera performs N×N splicing of F2 by means of mosaic composite splicing, and the adjacent detector single modules F8 overlap 10 rows (columns) of pixels F1.

[0051] As Figure 2 (a) and Figure 2 (b) shown, the low-temperature seamless splicing focal plane includes 4 splicing detector sub-assemblies, and their phases in the satellite coordinate system O_s-X_s Y_s Z_s are splicing detector sub-assembly A(X_s, Y_s), splicing detector sub-assembly B(-X_s, Y_s), splicing detector sub-assembly C(X_s, -Y_s), splicing detector sub-assembly D(-X_s, -Y_s). When projecting the satellite coordinate system O_s-X_s Y_s Z_s onto the earth coordinate system O_E-X_E Y_E Z_E, the detector single modules of each splicing detector sub-assembly are staggered and covered to achieve seamless detection.

[0052] As Figure 3 shown, the splicing detector sub-assembly adopts an integrated cold management technology for multi-temperature zone thermal control. The splicing detector sub-assembly works in the low-temperature optical temperature zone F5 and adopts an active refrigeration method. A cold screen temperature zone F6 is constructed by a radiation shield, and the radiation shield refrigeration is realized by a cold finger F13, a topological cold plate F12, and a flexible cold chain F15. The modular splicing single F9 element works in the detection temperature zone F7, and the refrigeration is realized by a cold finger F13, a topological cold plate F12, and a flexible cold chain F10.

[0053] As Figure 5 shown, the splicing detector sub-assembly is installed on the camera through a support flange F16, and the cold finger is installed on the support flange F16 through a hot-end radiator F14. The cold finger F13 is connected to the topological cold plate F12, and the topological cold plate F12 is connected to the modular detector unit F9 and the radiation shield F20 through a flexible cold chain F15 and a flexible cold chain F10 respectively. The modular detector unit F9 is installed on the splicing frame F11, and the radiation shield F20 and the splicing frame F11 are installed on the support flange F16 through a support assembly F17. The support assembly F17 includes a radiation shield support F22, a splicing frame support F23, and a limit component F21.

[0054] As Figure 4 shown, the modular detector unit is composed of a detector single module F8, a modular splicing substrate F27, an electrical flexible board F18, a flexible cold chain F10, etc. The modular splicing substrate F27 is provided with a low-temperature circuit F19 and interfaces for the flexible cold chain F10 and the electrical flexible board F18. The splicing steps are as follows:

[0055] Install the detector single module F8 on the modular splicing substrate F27 and fix it;

[0056] Bond the detector single module F8 to the cryogenic circuit F19 on the modular splicing substrate F27;

[0057] Install the flexible cold chain F10 and the electrical flexible board F18, and implement thermal control;

[0058] Install the modular splicing unit F9 on the splicing frame F11 and fix it.

[0059] In this embodiment, the 2.7k×2.7k detector single module mainly uses space-based infrared detector devices. Based on this device and in combination with the attached drawings, the detailed content and specific implementation of the present invention will be further described:

[0060] Refer to Figure 2 (b). In the satellite coordinate system O_s-X_s Y_s Z_s, the number of detector arrays of the spliced detector subassembly B is 5×5, the number of detector arrays of the spliced detector subassembly A is 4×5, the number of detector arrays of the spliced detector subassembly C is 5×4, and the number of detector arrays of the spliced detector subassembly D is 4×4.

[0061] As Figure 6 shown, the modular detector units are set to two types: 2×3 and 2×2. The spliced detector subassembly C can be split into 2 2×3 modular detector units F25 and 2 2×2 modular detector units F26, and the spliced detector subassembly D can be split into 4 2×2 modular detector units F26. The focal plane assembly has a total of 7 2×3 modular detector units F25 and 8 2×2 modular detector units F26, and 1 7-module detector unit.

[0062] As Figure 2 (b) shown, in the earth coordinate system O_E-X_E Y_E Z_E, the detector array scale of the cryogenic seamless spliced focal plane assembly is 24.3k×24.3k, which can achieve space-based global detection.

[0063] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

[0064] The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A cryogenic seamless splicing focal plane module applied to a space-based all-coverage remote sensing camera, characterized in that, Including: 4 splicing detector sub-assemblies, respectively located in four quadrants under the satellite coordinate system, optically spliced with each other to achieve a large-scale focal plane without splicing seams; among them, the splicing detector sub-assembly includes a number of modular splicing units (F9), and a number of modular splicing units (F9) form a detector array. When projecting the satellite coordinate system onto the earth coordinate system, the modular splicing units (F9) of each splicing detector sub-assembly are staggered and covered by the mosaic composite splicing method to eliminate the optical splicing seams between the splicing detector sub-assemblies and achieve space-based full-domain coverage detection; the splicing detector sub-assembly adopts a multi-temperature zone thermal control design method for thermal control to reduce the temperature fluctuation of the detector array and ensure temperature stability; the mosaic composite splicing method is specifically: each detector sub-assembly is mechanically spliced in a mosaic form, and the adjacent detector single modules in all splicing detector sub-assemblies overlap 5 to 15 rows of pixels. The splicing detector sub-assembly further includes a splicing frame (F11), a support assembly (F17), a support flange (F16), a radiation shield (F20), and a cooler hot-end radiator (F14); a number of modular splicing units (F9) are thermally installed on the splicing frame (F11), and the splicing frame (F11) is thermally insulated and installed on the support flange (F16) through the support assembly (F17); the radiation shield (F20) is arranged around the detector array and is thermally insulated and installed on the support flange (F16); the cooler hot-end radiator (F14) is installed on the support flange (F16) to cool the detector array. The cooler hot-end radiator (F14) includes a cold finger (F13), a topological cold plate (F12), a first flexible cold chain (F10), and a second flexible cold chain (F15). The cold finger (F13) and the topological cold plate (F12) are installed on the splicing frame (F11), the first flexible cold chain (F10) is on the modular splicing unit (F9), and the second flexible cold chain (F15) is installed on the outer side wall of the radiation shield (F20). The multi-temperature zone thermal control design method is specifically: The splicing detector sub-assembly is divided into multiple temperature zones, and the temperature zones include a detection temperature zone, a cold screen temperature zone, and a low-temperature optical temperature zone; the detection temperature zone is set inside the cold screen temperature zone, and the cold screen temperature zone is set inside the low-temperature optical temperature zone. The modular splicing unit (F9) and the splicing frame (F11) work in the detection temperature zone and are cooled by using the cold finger (F13), the topological cold plate (F12), and the first flexible cold chain (F10). The radiation shield (F20) works in the cold screen temperature zone; the cold screen temperature zone is cooled by using the cold finger (F13), the topological cold plate (F12), and the second flexible cold chain (F15). The support flange (F16) and the hot-end radiator (F14) work in the low-temperature optical temperature zone (F5).

2. The cryogenic seamless splicing focal plane module applied to a space-based all-coverage remote sensing camera according to claim 1, characterized in that: The modular splicing unit (F9) includes a detector single module (F8), a modular splicing substrate (F27), and an electrical flexible board (F18); a number of detector single modules (F8) are installed on the modular splicing substrate (F27), and a cryogenic circuit (F19) is provided on the modular splicing substrate (F27) to bond the detector single module (F8) to the cryogenic circuit (F19) on the modular splicing substrate (F27); the electronic signals of a number of detector single modules (F8) on the same modular splicing substrate (F27) are combined and led out to the electrical flexible board (F18); an installation interface for the first flexible cold chain (F10) and the electrical flexible board (F18) is provided on the modular splicing substrate (F27).

3. The cryogenic seamless splicing focal plane module applied to a space-based all-coverage remote sensing camera according to claim 1, characterized in that: The operating temperature of the detector single module (F8) is 90 - 100K, and the operating temperature of the spliced detector sub-assembly is 200 - 220K.

4. The cryogenic seamless splicing focal plane module applied to a space-based all-coverage remote sensing camera according to claim 1, characterized in that: The spliced detector sub-assembly is installed on the camera through a support flange (F16), and the cold finger (F13) is installed on the support flange (F16) through a hot end radiator (F14).

5. The cryogenic seamless splicing focal plane module applied to a space-based all-coverage remote sensing camera according to claim 1, characterized in that: The first flexible cold chain (F10) is designed with a main and backup structure.

6. The cryogenic seamless splicing focal plane module applied to a space-based all-coverage remote sensing camera according to claim 2, characterized in that: The temperature of the low-temperature optical temperature zone (F5) is 200 - 220K, the temperature of the cold screen temperature zone (F6) is 120 - 140K, and the temperature of the detection temperature zone (F7) is 80 - 110K.

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