A lightweight, compact, athermal infrared high-sensitivity camera structure

Abstract

A lightweight, compact, athermalized infrared high-sensitivity camera structure belongs to the field of space camera technology. This invention utilizes color separation filters to separate incident light into medium-wave and long-wavelength spectral bands. Each spectral band is further subdivided into five sub-bands using a filter wheel, achieving ten-band infrared imaging within the spectral range of 3.7um to 4.8um and 8um to 12.5um. All camera components are mounted on a single substrate, and a folding mirror is used to fold the optical path, resulting in a compact structure with a small size and light weight. The camera utilizes an athermal design, ensuring normal imaging in temperatures between -55°C and +60°C without thermal control equipment.

Description

Technical Field

[0001] The present invention relates to a lightweight, small-sized athermalized infrared high-sensitivity camera structure, belonging to the technical field of space cameras, and in particular to a lightweight, small-sized athermalized infrared multi-spectral camera mounted on a stratospheric floating platform or an aviation airborne platform. The operating spectrum range is 3.7um to 4.8um for medium-wave infrared and 8um to 12.5um for long-wave infrared. Background Art

[0002] High-resolution infrared imaging of the Earth from the stratosphere is a current research hotspot. The stratosphere is characterized by low temperatures and low pressure. Aerostats operating in the stratosphere have limited carrying and power supply capabilities, requiring the equipment they carry to be small, lightweight, and low-power. Current space-borne cameras cannot meet the high-sensitivity temperature imaging requirements of stratospheric aerostats. The main reasons are as follows:

[0003] (1) Infrared optical materials have different refractive indices at different temperatures. This causes the focal length of cameras assembled and tested in laboratory environments to change in high or low temperature environments, resulting in the camera not being able to produce clear images and reducing spatial and temperature resolution. Therefore, current satellite-borne and airborne cameras all have a complete temperature control system, which consists of a thermal controller, a heating device, and a radiation heat dissipation device. The entire system is heavy, power-hungry, bulky, and complex. When the ambient temperature is lower than the normal operating temperature range of the camera, the thermal controller controls the heating plate to heat the camera; when the camera's own temperature is higher than the normal operating temperature range, the radiation heat dissipation device starts to radiate heat to ensure that the camera temperature does not exceed the allowable temperature range. In the stratospheric environment, due to power supply capacity limitations, the platform layer floating platform cannot provide sufficient heating power consumption for the camera; at the same time, due to the weight and volume limitations of the airship pod, the camera cannot carry a radiation heat dissipation device. Therefore, current satellite-borne cameras are not compatible with current stratospheric airship pods.

[0004] (2) The infrared imaging spectrum of the camera is in the mid-wave infrared range of 3.7um to 4.8um and 8um to 12.5um. The spectrum is relatively wide and the infrared detector is not sensitive in this spectrum range. At present, the infrared noise equivalent temperature difference (NETD) of the same type of satellite-borne infrared camera in the mid-wave spectrum is about 30mK and the infrared noise equivalent temperature difference (NETD) in the long-wave spectrum is about 100mK, and the temperature resolution is low.

[0005] (3) Currently, satellite-borne infrared cameras do not have the ability to perform filter splitting and ten-band imaging.

[0006] (4) Currently, satellite-borne infrared cameras do not have the ability to operate normally in the temperature range of -55℃ to +60℃. Summary of the Invention

[0007] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology and provide a lightweight and compact athermal infrared high-sensitivity camera structure, which uses a color separation plate to divide the incident light into a medium-wave spectrum band and a long-wave spectrum band, and each spectrum band is further subdivided into five sub-spectral bands by a filter wheel, thereby realizing infrared ten-spectral band imaging.

[0008] The technical solution of the present invention is: a lightweight and compact athermal infrared high-sensitivity camera structure, comprising:

[0009] The double-layer frame base plate is the camera's load-bearing structure, used to install the color separation filter assembly, medium-wave channel, and long-wave channel. It includes an upper plate and a lower plate. The upper plate is used to install the camera's electronic equipment, and the lower plate is provided with a light inlet. The color separation filter assembly is hoisted on the upper plate.

[0010] The color separation filter assembly has a surface coating layer, which is used to split the medium-wave and long-wave spectrum of the incident light, reflect the medium-wave spectrum light into the medium-wave channel, and transmit the long-wave spectrum light into the long-wave channel;

[0011] The medium wave channel is installed on the substrate and receives the incident light of the medium wave spectrum reflected by the color separation filter assembly. It subdivides the spectrum into five sub-spectral bands through the medium wave filter wheel to achieve medium wave five-spectral band imaging.

[0012] The long-wave channel is installed on the substrate and receives the incident light of the long-wave spectrum band transmitted by the color separation film assembly. It subdivides the spectrum band into 5 sub-spectral bands through the long-wave filter wheel to achieve long-wave 5-spectral band imaging.

[0013] Furthermore, the substrate further includes vertical plates; the vertical plates isolate the double-layer frame structure of the substrate into different areas, so as to enhance the rigidity of the double-layer frame structure and shield external stray light.

[0014] Furthermore, the lower surface of the lower plate is the reference surface of the camera, the assembly and testing of the camera optical components are based on the lower surface of the lower plate, and the machining of the substrate is based on the lower surface of the lower plate.

[0015] Furthermore, the color separation film assembly includes a color separation film, a color separation film bracket, and an adhesive spot; the color separation film is fixedly connected to the color separation film bracket, and a circular adhesive spot is injected into the gap between the two through a small hole on the side of the color separation film bracket. The adhesive spot is 0.3 mm thick and 3 mm in diameter, and there are eight of them, which are distributed in a circle on the outer side of the color separation film; the light incident surface coating layer of the color separation film is used to reflect the medium-wave spectrum and transmit the long-wave spectrum, and the output surface of the color separation film is coated with an anti-reflection film.

[0016] Furthermore, the dichroic plate is a circular plane lens with a diameter of 55 mm and a thickness of 3 mm. The dichroic plate is made of zinc tin, and the dichroic plate bracket is made of aluminum alloy. It is bonded to the dichroic plate bracket with low-temperature silicone rubber to compensate for the mismatch between thermal expansion and contraction.

[0017] Furthermore, the medium wave channel includes a medium wave front lens group, a medium wave folding mirror, a medium wave focusing lens group, a medium wave rear lens group, a medium wave filter wheel assembly, and a medium wave detector refrigerator assembly;

[0018] The medium wave front lens group includes a medium wave front lens barrel, a medium wave front lens bracket, and a first medium wave front lens and a second medium wave front lens. The two medium wave front lenses are fixedly connected to the medium wave front lens barrel; the medium wave front lens barrel is mounted on the medium wave front lens bracket; the medium wave front lens bracket is hoisted on the upper plate; the surfaces of the first medium wave front lens and the second medium wave front lens are coated with an anti-reflection coating that transmits the medium wave spectrum; the surfaces of the medium wave front lens barrel and the medium wave front lens bracket are black anodized; the medium wave front lens group is hoisted and mounted on the upper plate;

[0019] The medium fold mirror is a reflector. Its mirror body and bracket are an integrated structure. The material is aluminum alloy used for space reflectors. The reflective surface is aluminum-coated, and the surface of other parts is black anodized. The bracket of the reflector is fixed to the lower plate by 3 screws. The screw holes are cut with 0.5mm unloading grooves.

[0020] The medium wave focusing lens assembly 3-3 includes a medium wave focusing spherical lens, a medium wave focusing lens frame, a medium wave focusing lens bracket, a focusing mechanism, and a focusing mechanism mounting seat; the medium wave focusing spherical lens is bonded to the medium wave focusing lens frame with a low-temperature silicone rubber adhesive; the outer side of the medium wave focusing lens frame is threaded and fixed to the medium wave focusing lens bracket via a threaded pair; the focusing mechanism is fixed to the focusing mechanism mounting seat via four screws; the medium wave focusing spherical lens is made of single crystal silicon, and its surface is coated with an anti-reflection coating that transmits the medium wave spectrum; the medium wave focusing lens frame, the medium wave focusing lens bracket, and the focusing mechanism mounting seat are all made of aluminum alloy with a black anodized surface; the focusing mechanism is a one-dimensional lifting platform used for one-dimensional movement of the medium wave focusing spherical lens along the central axis, with a movement range of ±6mm;

[0021] The MW rear lens group includes a first MW rear lens, a second MW rear lens, a third MW rear lens, a MW rear lens barrel, and a MW rear lens holder. The first, second, and third MW rear lenses are bonded to corresponding positions within the inner cavity of the MW rear lens barrel using low-temperature silicone rubber. The outer side of the MW rear lens barrel is threaded and mounted on the MW rear lens holder via a threaded pair. All three MW rear lenses are spherical lenses made of single-crystal silicon, with an anti-reflection coating that transmits the MW spectrum. The MW rear lens barrel and MW rear lens holder are made of aluminum alloy with a black anodized surface. The MW rear lens holder is mounted on the lower plate via four screws.

[0022] The MW filter wheel assembly includes a filter, filter frame, turntable, motor, gear pair, bearings, and MW filter wheel mount. The filter is bonded to the filter frame with low-temperature silicone rubber. The filter frame is secured to the turntable with three screws. The gear pair is mounted on the MW filter wheel mount via bearings. The motor drives the turntable through the gear pair. Five filters are made of single-crystal germanium and are mounted on the turntable. Each filter has a different film layer, allowing light from different spectral bands to pass through.

[0023] The MW detector refrigerator assembly includes a dewar, a refrigerator, and a MW detector refrigerator bracket. The MW detector refrigerator bracket is made of aluminum alloy with a black anodized surface. The dewar and refrigerator are mounted on the bracket, which is then mounted on the lower plate of the base plate.

[0024] The medium wave folding mirror, the medium wave focusing lens group, the medium wave rear lens group and the medium wave filter wheel assembly are installed on the lower plate.

[0025] Furthermore, the two medium wave front lenses are bonded into the medium wave front lens barrel, and the bonding glue is low-temperature silicone rubber; threads are processed on the outside of the medium wave front lens barrel and are installed on the medium wave front lens bracket through a thread pair; the first medium wave front lens and the second medium wave front lens are made of single crystal silicon, and the medium wave front lens barrel and the medium wave front lens bracket are made of aluminum alloy; the medium wave front lens bracket is hoisted to the upper plate by 4 screws.

[0026] Furthermore, the long-wave channel includes a long-wave focusing lens assembly, a long-wave folding mirror assembly, a long-wave lens assembly, a long-wave filter wheel assembly, and a long-wave detector refrigerator assembly;

[0027] The long-wave focusing lens assembly includes a long-wave focusing lens, a long-wave focusing lens frame, a long-wave focusing lens bracket, a one-dimensional lifting platform, and a long-wave focusing lens base; the long-wave focusing lens is a spherical mirror, fixedly connected to the long-wave focusing lens frame, and the adhesive is low-temperature silicone rubber; the long-wave focusing lens frame is mounted on the long-wave focusing lens bracket; the long-wave focusing lens bracket is mounted on the one-dimensional lifting platform; the lifting platform is mounted on the long-wave focusing lens base; the long-wave focusing lens base is mounted on the lower plate; the surface of the long-wave focusing lens is coated with an anti-reflection film that transmits the long-wave spectrum;

[0028] The long-wave fold mirror assembly includes a long-wave fold mirror and a long-wave fold mirror bracket. There are two long-wave fold mirrors, which are used to fold the light path and are installed on the long-wave fold mirror bracket with three screws. The long-wave fold mirror bracket is installed on the lower plate with four screws. The surface of the long-wave fold mirror is coated with an aluminum reflective film, and the surface of the long-wave fold mirror bracket is black anodized.

[0029] The long-wave lens assembly includes a first long-wave lens, a second long-wave lens, a third long-wave lens, an inner lens barrel, an outer lens barrel, and a long-wave lens base; the first long-wave lens is bonded to the inner side of the inner lens barrel, and the bonding glue is low-temperature silicone rubber; the second long-wave lens and the third long-wave lens are bonded to the inner side of the outer lens barrel, and the bonding glue is low-temperature silicone rubber; the openings at both ends of the inner lens barrel are different in size, and the side with the larger opening is processed with an internal thread, and the side with the larger opening of the outer lens barrel is processed with an external thread that matches it, and the two are fixed by a thread pair; the outer side of the middle part of the outer lens barrel is processed with an external thread that matches the internal thread of the long-wave lens base, and is fixed to the long-wave lens base by a thread pair; the long-wave lens base is mounted on the lower plate by 4 screws; the material of the first long-wave lens, the second long-wave lens, and the third long-wave lens are all single-crystal germanium, and the surface is coated with an anti-reflection film that transmits the long-wave spectrum; the inner lens barrel, the outer lens barrel, and the long-wave lens base are all made of aluminum alloy, and the surface is black anodized; the long-wave lens assembly is hoisted and mounted on the upper plate;

[0030] The structures of the long-wave filter wheel assembly and the medium-wave filter wheel assembly are the same except that the surface film layer of the five filters is an anti-reflection film used to increase the transmittance of the long-wave spectrum; the long-wave focusing lens assembly, long-wave folding mirror assembly, and long-wave filter wheel assembly are installed on the lower plate;

[0031] The long-wave detector refrigerator assembly comprises a Dewar assembly and a refrigerator assembly, which are independently mounted on a vertical plate of the base plate.

[0032] Furthermore, the long-wave focusing lens is bonded to the long-wave focusing lens frame, and the bonding glue is low-temperature silicone rubber; the outer side of the long-wave focusing lens frame is processed with threads and is installed on the long-wave focusing lens bracket through a threaded pair; the long-wave focusing lens bracket is installed on the one-dimensional lifting platform through 4 screws; the long-wave focusing lens base is installed on the lower plate through 4 screws; the material of the long-wave focusing lens is single crystal germanium, and the surface is coated with an anti-reflection film that transmits the long-wave spectrum; the long-wave focusing lens frame, the long-wave focusing lens bracket, and the long-wave focusing lens base are all made of aluminum alloy, and the surface is black anodized; the one-dimensional lifting platform drives the long-wave focusing lens to move along the central axis, with a stroke of ±6mm.

[0033] Furthermore, the substrate is made of aluminum alloy and is integrally formed by 3D printing, with a fundamental frequency greater than 600 Hz; the medium-wave spectrum range is 3.7 um to 4.8 um, and the long-wave spectrum range is 8 um to 12.5 um.

[0034] The advantages of the present invention compared with the prior art are:

[0035] 1. Compared with similar infrared multispectral cameras, this camera adopts a thermal control-free design and does not require any supporting equipment such as thermal controllers, heating equipment, or radiation heat dissipation equipment. The camera's power consumption is less than 70W, which is 20W to 30W lower than current similar devices. The camera weighs 13kg, 4kg lighter than similar devices. The camera has a volume of 310mm×310mm×150mm and is compatible with stratospheric aerostat pods and aircraft-borne optoelectronic pods with a diameter of 350mm.

[0036] 2. Compared with similar infrared multispectral cameras, all components of the present invention are installed on the same substrate, and the processing, installation, and testing standards are unified, which is conducive to ensuring the strict positional relationship of each important optical component of the camera, thereby improving the camera image quality and reducing the difficulty of camera installation;

[0037] 3. The baseboard adopts a double-layer duplex structure. The upper plate, lower plate, and vertical plate can all provide installation interfaces. The color separation plate assembly, medium-wave front lens assembly, and long-wave lens assembly are hoisted on the upper plate, the medium-wave detector refrigerator assembly and the long-wave detector refrigerator assembly are installed on the middle wall of the baseboard, and other equipment is installed on the lower plate. This solves the problem of insufficient installation space caused by the minimum gap of 5mm between adjacent optical components and facilitates the compact, lightweight and miniaturized design of the camera. The vertical plate has a light-blocking effect, reducing the background noise caused by stray light, which helps to improve the system signal-to-noise ratio.

[0038] 4. The substrate structure is one-piece, suitable for the development of 3D laser printing technology, with a short development cycle. The central wall of the substrate divides the substrate into different cabins, increasing the overall rigidity. It also has the function of shading and preventing excess objects from entering the optical path. The one-piece configuration is conducive to heat conduction, good optical and mechanical temperature uniformity, and thermal stress has little effect on the surface shape of optical components, which is conducive to improving image quality.

[0039] 5. The color separation sheet, lens, filter and structural frame are all bonded with low-temperature silicone rubber. This silicone rubber can adapt to temperature changes from -55℃ to +60℃ without affecting the optical performance of the lens.

[0040] 6. The filter wheel spectroscopic technology is used to achieve infrared spectral imaging in ten spectral bands, with a spectral range of 3.7um to 4.8um and 8um to 12.5um. The medium-wave filter wheel and long-wave filter wheel work independently, and the corresponding filters can be cut into the light path as needed to obtain image information of different spectral bands of the target, with flexible working modes. The motors of the medium-wave filter wheel assembly and the long-wave filter wheel assembly are both mature motor products, which can adapt to the working environment of -55℃ to +60℃ and have high reliability.

[0041] 7. The camera's medium-wave channel and long-wave channel can independently image and can also image the same target simultaneously; the medium-wave detector and long-wave detector have the same specifications, with a pixel size of 640×512 and a pixel size of 25μm, which facilitates medium-wave and long-wave image fusion processing and improves target recognition accuracy;

[0042] 8. After testing, the temperature resolution of the medium-wave infrared channel is 18mK, and the temperature resolution of the long-wave channel is 59.8mK. The indicators are better than the temperature resolution of on-orbit satellite infrared cameras (30mK, 100mK), reaching the domestic leading level. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0044] Figure 1 This is a diagram of the overall configuration of the camera of the present invention;

[0045] Figure 2 This is the optical path diagram of the camera of the present invention;

[0046] Figure 3 This is a configuration diagram of the base 1 of the present invention;

[0047] Figure 4 This is a structural diagram of the color separation sheet assembly 2 of the present invention;

[0048] Figure 5 This is a structural diagram of the wavefront lens group 3-1 in the present invention;

[0049] Figure 6 This is a structural diagram of the folding mirror 3-2 in the present invention;

[0050] Figure 7 This is a structural diagram of the medium-wave focusing lens assembly 3-3 of the present invention;

[0051] Figure 8 This is a structural diagram of the medium wave rear lens group 3-4 of the present invention;

[0052] Figure 9 This is a structural diagram of the medium wave filter wheel assembly 3-5 of the present invention;

[0053] Figure 10 This is a structural diagram of the medium wave detector refrigerator 3-6 of the present invention;

[0054] Figure 11 This is a structural diagram of the long-wave focusing lens assembly 4-1 of the present invention;

[0055] Figure 12 This is a structural diagram of the long wave fold mirror assembly 4-2 of the present invention;

[0056] Figure 13 This is a structural diagram of the long-wave lens assembly 4-3 of the present invention;

[0057] Figure 14 This is a structural diagram of the long-wave detector refrigerator component 4-5 of the present invention. DETAILED DESCRIPTION

[0058] In order to better understand the above technical solution, the technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0059] In the solution provided in the embodiment of the present invention, Figure 1 、 Figure 2 As shown, the present invention includes a substrate 1, a color separation plate assembly 2, a medium-wave channel 3, and a long-wave channel 4; in the order in which light enters, the components included in the medium-wave channel 3 are, in sequence, a medium-wave front lens group 3-1, a medium-wave folding mirror 3-2, a medium-wave focusing lens assembly 3-3, a medium-wave rear path group 3-4, a medium-wave filter wheel assembly 3-5, and a medium-wave detector refrigerator assembly 3-6; in the order in which light enters, the components included in the long-wave channel 4 are, in sequence, a long-wave focusing lens assembly 4-1, a long-wave folding mirror assembly 4-2, a long-wave lens assembly 4-3, a long-wave filter wheel assembly 4-4, and a long-wave detector refrigerator assembly 4-5; all components of the color separation plate assembly 2, the medium-wave channel 3, and the long-wave channel 4 are mounted on the substrate 1.

[0060] The optical path of the present invention is as follows Figure 2 As shown, the external light is split by the color separation plate assembly 2, reflecting the medium-wave spectrum and transmitting the long-wave spectrum; the reflected medium-wave spectrum light enters the medium-wave front lens assembly 3-1, the medium-wave folding mirror assembly 3-2, the medium-wave focusing lens assembly 3-3, the medium-wave rear lens assembly 3-4, the medium-wave filter wheel assembly 3-5 in sequence, and finally reaches the medium-wave detector refrigerator assembly 3-6; the transmitted long-wave spectrum light enters the long-wave focusing lens assembly 4-1, the long-wave folding mirror assembly 4-2, the long-wave lens assembly 4-3, the long-wave filter wheel assembly 4-4 in sequence, and finally reaches the long-wave detector refrigerator assembly 4-5.

[0061] like Figure 3 As shown, the baseplate is a double-layer composite structure. The upper plate 1-1, lower plate 1-2, and vertical plates 1-3 all provide mounting interfaces. The vertical plates provide structural reinforcement and light-shielding functions. The baseplate is recommended to be manufactured using 3D-printed aluminum alloy. This one-piece molding offers high rigidity and excellent thermal conductivity, ensuring camera structural stability and temperature uniformity. The baseplate surface is black anodized to eliminate stray light.

[0062] like Figure 4 As shown, the color separation plate assembly 2 includes a color separation plate 2-1, a color separation plate holder 2-2, and adhesive spots 2-3; the color separation plate is a circular plane lens with a diameter of 55mm and a thickness of 3mm, and is bonded to the annular cavity of the color separation plate holder 2-2. The adhesive is low-temperature silicone rubber. The adhesive is injected through a small hole on the side of the color separation plate holder 2-2 to form circular adhesive spots in the gap between the two. The adhesive spots are 0.3mm thick and 3mm in diameter. There are eight of them, which are distributed circumferentially on the outer side of the color separation plate 2-1. The light incident surface of the color separation plate 2-1 is coated with a special film layer that can reflect the medium-wave spectrum and transmit the long-wave spectrum, and the output surface is coated with an anti-reflection film. The material of the color separation plate 2-1 is zinc tin, and the material of the color separation plate holder 2-2 is aluminum alloy. The low-temperature silicone rubber is used to bond the lens and the holder, and can compensate for the mismatch between the thermal expansion and contraction of the two.

[0063] like Figure 5 As shown, the medium-wave front lens group 3-1 includes lens 3-1-1 and lens 3-1-2. The two lenses are bonded to the cavity of the lens barrel 3-1-3, and the lens surfaces are close to the steps in the lens barrel; low-temperature silicone rubber is injected through the small holes in the lens barrel wall to bond the lenses to the lens barrel; the outer side of the lens barrel 3-1-3 is processed with external threads, and the inner ring cavity of the bracket 3-1-4 is processed with internal threads. The two are fastened together by a threaded pair, and anti-loosening glue is applied at the interface; the material of lens 3-1-1 and lens 3-1-2 is single crystal silicon, and the lens barrel 3-1-2 and bracket 3-1-4 are aluminum alloy; bracket 3-1-4 is hoisted to the upper plate of substrate 1 by 4 screws; the surface of lens 3-1-1 and lens 3-1-2 is coated with anti-reflection film that transmits the medium-wave spectrum; the surface of lens barrel 3-1-2 and bracket 3-1-4 is black anodized.

[0064] like Figure 6 As shown, the medium fold mirror 3-2 is a reflector, and the mirror body and the bracket are integrated. The material is aluminum alloy material used for space reflectors, the reflecting surface is aluminum-coated, and the surface of other parts is black anodized; the reflector bracket is fixed to the lower plate of the substrate 1 by 3 screws, and a 0.5mm unloading groove is cut near the screw hole.

[0065] like Figure 7As shown, the medium wave focusing lens assembly 3-3 includes a spherical lens 3-3-1, a lens frame 3-3-2, a bracket 3-3-3, a focusing mechanism 3-3-4, and a focusing mechanism mounting seat 3-3-5; the lens 3-3-1 is bonded to the lens frame 3-3-2 with low-temperature silicone rubber; the outer side of the lens frame 3-3-2 is machined with an external thread, and the inner side of the annular cavity of the bracket 3-3-3 is machined with an internal thread, and the two are fixed by a threaded pair; the focusing mechanism 3-3-4 is a commercial micro-one-dimensional lift Lowering stage; focusing mechanism 3-3-4 is fixed to mounting base 3-3-5 by 4 screws; lens 3-3-1 is made of single-crystal silicon, with anti-reflection coating on the surface that transmits the medium-wave spectrum; lens frame 3-3-2, bracket 3-3-3, and focusing mechanism mounting base 3-3-5 are all made of aluminum alloy with black anodized surface; focusing mechanism 3-3-4 is a commercially mature miniature one-dimensional lifting stage, used for one-dimensional movement of lens 3-3-1 along the central axis, with a movement range of ±6mm.

[0066] like Figure 8 As shown, the medium-wave rear lens group 3-4 includes a rear lens 3-4-1, a rear lens 3-4-2, a rear lens 3-4-3, a lens barrel 3-4-4, and a support 3-4-5; the three lenses are bonded to the lens barrel 3-4-4 by low-temperature silicone rubber; the lens assembly sequence is as follows: place the rear lens 3-4-3 on the bottom surface of the lens barrel, inject adhesive through the corresponding small hole on the side wall of the lens barrel, and cure it for 3 days; then assemble the rear lens 3-4-2 and the rear lens 3-4-3 in sequence; the outer side of the lens barrel 3-4-4 is machined with an external thread, and the inner side of the annular cavity of the support 3-4-5 is machined with an internal thread, and the two are fastened by a threaded pair; the lenses are all spherical lenses, made of single-crystal silicon, and the surface is coated with an anti-reflection film that transmits the medium-wave spectrum; the lens barrel 3-4-4 and the support 3-4-5 are made of aluminum alloy, and the surface is black anodized; the support 3-4-5 is mounted on the lower plate of the substrate 1 by 4 screws.

[0067] like Figure 9As shown, the medium wave filter wheel assembly 3-5 includes a filter 3-5-1, a filter frame 3-5-2, a turntable 3-5-3, a motor 3-5-4, a gear pair 3-5-5, a bearing 3-5-6, and a mounting seat 3-5-7; the filter 3-5-1 is bonded to the filter frame 3-5-2 using low-temperature silicone rubber; the filter frame is fixed to the turntable 3-5-3 by three screws; the gear pair 3-5-5 is mounted on the mounting seat via the bearing 3-5-6. 3-5-7; motor 3-5-4 drives turntable 3-5-3 via gear pair 3-5-5; filters 3-5-1 are made of single-crystal germanium, with five filters in total, each with a different coating to transmit light in a different spectral range; filter frame 3-5-2, turntable 3-5-3, and mounting base 3-5-7 are made of aluminum alloy, black anodized to eliminate stray light; gear pair 3-5-5 is also made of aluminum alloy, coated with molybdenum disulfide to prevent cold welding. The configuration of long-wave filter wheel assembly 4-4 is identical to that of medium-wave filter wheel assembly 3-5, with the filter substrate made of single-crystal germanium and each filter coated with a different antireflection coating to transmit a different long-wave spectral range.

[0068] like Figure 10 As shown, the medium-wave detector refrigerator assembly 3-6 includes a dewar 3-6-1, a refrigerator 3-6-2, and a bracket 3-6-3. The refrigerator is a small Stirling refrigerator. The effective pixel size of the medium-wave detector in the dewar is 640×512, the pixel size is 25μm, the NETD≤15mk@300K, and the focal plane operating temperature is 80K±3K. The bracket 3-6-3 is made of aluminum alloy with a black anodized surface. The copper tube between the dewar and the refrigerator is 3mm in diameter and about 300mm in length. Its configuration is bent according to the layout.

[0069] like Figure 11 As shown, the long-wave focusing lens assembly 4-1 includes a lens 4-1-1, a lens frame 4-1-2, a bracket 4-1-3, a micro one-dimensional lifting platform 4-1-4, and a base 4-1-5; the lens is a spherical mirror, bonded to the lens frame 4-1-2, and the bonding glue is low-temperature silicone rubber; the outer side of the lens frame 4-1-2 is processed with an external thread, and the inner side of the annular cavity of the bracket 4-1-3 is internally threaded, and the two are fastened by a threaded pair; the bracket 4-1-3 is mounted on the micro one-dimensional lifting platform by 4 screws Platform 4-1-4, lifting platform 4-1-4 is a mature commercial product, installed on the base 4-1-5; the base 4-1-5 is installed on the lower plate of the substrate 1 by 4 screws; the lens material is single crystal germanium, and the surface is coated with an anti-reflection film that transmits the long-wave spectrum; the lens frame 4-1-2, bracket 4-1-3, and base 4-1-5 are all made of aluminum alloy, and the surface is black anodized; the one-dimensional lifting platform 4-1-4 drives the lens 4-1-1 to move along the central axis, with a stroke of ±6mm.

[0070] like Figure 12As shown, the long-wave fold mirror assembly 4-2 includes a fold mirror 4-2-1 and a bracket 4-2-2; there are two fold mirrors, which are used to fold the light path and are made of aluminum alloy. Each fold mirror is installed on the bracket 4-2-2 by three screws; the normals of the two fold mirrors are perpendicular, and the light path is parallel to the original light path after folding; the bracket 4-2-2 is installed on the lower plate of the substrate 1 by four screws; the surface of the fold mirror 4-2-1 is coated with an aluminum reflective film, and the surface of the fold mirror bracket 4-2-2 is black anodized.

[0071] like Figure 13 As shown, the long-wave lens assembly 4-3 includes three spherical lenses, a long-wave lens 4-3-1, a lens 4-3-2, a lens 4-3-3, an inner lens barrel 4-3-4, an outer lens barrel 4-3-5, and a base 4-3-6; the long-wave lens 4-3-1 is bonded to the inner side of the inner lens barrel 4-3-4, and the bonding glue is low-temperature silicone rubber; the assembly sequence of the lens 4-3-2, the lens 4-3-3 and the outer lens barrel 4-3-5 is as follows: place the small plane of the lens 4-3-2 on the bottom surface of the outer lens barrel 4-3-5, inject the bonding glue through the small hole in the barrel wall, and cure it for 3 days. The same method is used to complete the assembly of lens 4-3-3; the middle part of the inner lens barrel 4-3-4 is a flange, and external threads are processed on both the left and right sides. The left external thread is screwed to the outer lens barrel 4-3-5, and the right external thread is screwed to the base; the base 4-3-6 is installed on the lower plate of substrate 1 by 4 screws; the materials of lens 4-3-1, lens 4-3-2, and lens 4-3-3 are all single crystal germanium, and the surface is coated with an anti-reflection film that transmits the long wavelength spectrum; the lens barrel 4-3-4, lens barrel 4-3-5, and base 4-3-6 are all made of aluminum alloy, and the surface is black anodized.

[0072] like Figure 14 As shown, the long-wave detector refrigerator assembly 4-5 comprises a Dewar assembly 4-5-1 and a refrigerator assembly 4-5-2. The refrigerator is a small Stirling refrigerator. The long-wave detector has an effective pixel size of 640×512, a pixel size of 25 μm, a NETD ≤ 35 mk at 300 K, and a focal plane operating temperature of 60 K ± 3 K. The refrigerator controller 4-5-3 is a dedicated refrigerator controller. The bracket 4-5-4 is made of aluminum alloy with a black anodized surface. The long-wave detector refrigerator assembly 4-5 is a mature commercial product.

[0073] Working principle of the present invention:

[0074] Incident light is split by the dichroic filter, with the mid-infrared spectrum reflected into the medium-wavelength (MW) channel and the long-wavelength (LW) infrared spectrum transmitted into the long-wavelength (LW) infrared channel. The split MWIR light is then focused by a lens, reflected by a folding mirror, and subdivided by filters before entering a MWIR detector. The optical signal is converted into an electrical signal, which is then processed by the camera electronics and output as a MWIR image. Similarly, the LWIR light is focused by a lens, reflected by a folding mirror, and subdivided by filters before entering a LWIR detector. Finally, the electronics process the signal and output a LWIR image. The folding mirror deflects the light path, reducing the camera's size. The filter wheel subdivides the spectrum into five sub-bands, allowing each camera to capture images in ten spectral bands.

[0075] All subassemblies of the camera are mounted on a baseplate and share the same assembly, adjustment, and testing standards. The baseplate's double-layer composite configuration ensures high structural rigidity for the entire device (with a fundamental frequency greater than 600 Hz). The baseplate is constructed of aluminum alloy with excellent thermal conductivity and is integrally formed using 3D printing technology to ensure camera temperature uniformity. The linear expansion coefficients of the camera's optical components, optical brackets, and baseplate materials match each other. The optical components and support structure are bonded together using low-temperature silicone rubber, which compensates for the stress caused by thermal expansion and contraction between the optical components and the metal structure. This achieves a heatless design for the camera, ensuring high-resolution imaging in the temperature range of -55°C to +60°C without thermal control equipment. The measured temperature resolution in the long-wave spectrum is 59.8mK.

[0076] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0077] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A lightweight, compact, athermal infrared high-sensitivity camera structure, characterized in that: include: The double-layer frame substrate (1) is a load-bearing structure for the camera and is used to install the color separation filter assembly (2), the medium-wave channel (3) and the long-wave channel (4), and includes an upper plate (1-1) and a lower plate (1-2); the upper plate (1-1) is used to install the camera electronic equipment, and the lower plate (1-2) is provided with a light inlet; the color separation filter assembly (2) is hoisted on the upper plate (1-1); A color separation plate assembly (2) having a surface coating layer for separating the medium-wave and long-wave spectrums of incident light, reflecting the medium-wave spectrum light into the medium-wave channel (3) and transmitting the long-wave spectrum light into the long-wave channel (4); The medium wave channel (3) is mounted on the substrate (1), receives incident light of the medium wave spectrum reflected by the color separation plate assembly (2), and subdivides the spectrum into five sub-spectral bands through the medium wave filter wheel assembly (3-5), thereby realizing medium wave five-spectral band imaging; The long-wave channel (4) is mounted on the substrate (1), receives incident light of the long-wave spectrum band transmitted by the color separation plate assembly (2), and subdivides the spectrum band into five sub-spectral bands through the long-wave filter wheel assembly (4-4), thereby realizing long-wave five-spectral band imaging.

2. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 1, characterized in that: The substrate (1) further comprises vertical plates (1-3); the vertical plates (1-3) isolate the double-layer frame structure of the substrate (1) into different areas, and are used to strengthen the rigidity of the double-layer frame structure while shielding external stray light.

3. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 1, characterized in that: The lower surface of the lower plate (1-2) is the reference surface of the camera. The assembly, adjustment and testing of the camera optical components are based on the lower surface of the lower plate (1-2). The mechanical processing of the substrate (1) is based on the lower surface of the lower plate (1-2).

4. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 1, characterized in that: The color separation film assembly (2) comprises a color separation film (2-1), a color separation film bracket (2-2), and adhesive spots (2-3); the color separation film (2-1) is fixedly connected to the color separation film bracket (2-2), and circular adhesive spots (2-3) are formed by injecting liquid into the gap between the two through a small hole on the side of the color separation film bracket (2-2); the adhesive spots (2-3) are 0.3 mm thick and 3 mm in diameter, and there are eight of them in total, which are distributed on the outer side of the color separation film (2-1); the light incident surface coating layer of the color separation film (2-1) is used to reflect the medium-wave spectrum and transmit the long-wave spectrum, and the light exit surface of the color separation film (2-1) is coated with an anti-reflection film.

5. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 4, characterized in that: The color separation sheet (2-1) is a circular plane lens with a diameter of 55 mm and a thickness of 3 mm. The color separation sheet (2-1) is made of zinc tin, and the color separation sheet bracket (2-2) is made of aluminum alloy. The color separation sheet is bonded to the color separation sheet bracket (2-2) with low-temperature silicone rubber as the bonding glue to compensate for the mismatch between the thermal expansion and contraction of the two.

6. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 1, characterized in that: The medium wave channel (3) comprises a medium wave front lens group (3-1), a medium wave folding mirror (3-2), a medium wave focusing lens group (3-3), a medium wave rear lens group (3-4), a medium wave filter wheel assembly (3-5), and a medium wave detector refrigerator assembly (3-6); The medium wavefront lens group (3-1) includes a medium wavefront lens barrel (3-1-3), a medium wavefront lens bracket (3-1-4), a first medium wavefront lens (3-1-1), and a second medium wavefront lens (3-1-2). The two medium wavefront lenses are fixedly connected in the medium wavefront lens barrel (3-1-3); the medium wavefront lens barrel (3-1-3) is installed on the medium wavefront lens bracket (3-1-4); the medium wavefront lens bracket (3-1-4) is hoisted on the upper plate (1-1); the surfaces of the first medium wavefront lens (3-1-1) and the second medium wavefront lens (3-1-2) are coated with an anti-reflection film that transmits a medium wave spectrum; the surfaces of the medium wavefront lens barrel (3-1-3) and the medium wavefront lens bracket (3-1-4) are black anodized; the medium wavefront lens group (3-1) is hoisted and installed on the upper plate (1-1); The medium fold mirror (3-2) is a reflector, and its mirror body and bracket are an integrated structure. The material is aluminum alloy material used for space reflectors, the reflective surface is aluminum-coated, and the surface of other parts is black anodized. The bracket of the reflector is fixed to the lower plate (1-2) by 3 screws, and the screw holes are cut with 0.5mm unloading grooves. The medium wave focusing lens assembly 3-3 comprises a medium wave focusing spherical lens (3-3-1), a medium wave focusing lens frame (3-3-2), a medium wave focusing lens bracket (3-3-3), a focusing mechanism (3-3-4), and a focusing mechanism mounting seat (3-3-5); the medium wave focusing spherical lens (3-3-1) is bonded to the medium wave focusing lens frame (3-3-2) using low temperature silicone rubber as the bonding adhesive; the outer side of the medium wave focusing lens frame (3-3-2) is threaded and fixed to the medium wave focusing lens bracket (3-3-3) through a threaded pair; the focusing mechanism (3-3-4) is bonded to the medium wave focusing lens frame (3-3-2) using low temperature silicone rubber as the bonding adhesive; the outer side of the medium wave focusing lens frame (3-3-2) is threaded and fixed to the medium wave focusing lens bracket (3-3-3) through a threaded pair; the focusing mechanism (3-3-5) is bonded to the medium wave focusing lens frame (3-3-2) using low temperature silicone rubber as the bonding adhesive; the outer side of the medium wave focusing lens frame (3-3-2) is threaded and fixed to the medium wave focusing lens bracket (3-3-3) through a threaded pair; the focusing mechanism (3-3-4) is bonded to the medium wave focusing lens frame (3-3-2) using low temperature silicone rubber as the bonding adhesive; the focusing mechanism (3-3-5) is bonded to the medium wave focusing lens frame (3-3-2) using low temperature silicone rubber as the bonding adhesive; the focusing mechanism (3-3-4) is bonded to the medium wave focusing lens frame (3-3-4 ... The MW focusing spherical lens (3-3-1) is made of single crystal silicon and coated with an antireflection coating that transmits the MW spectrum. The MW focusing lens frame (3-3-2), MW focusing lens bracket (3-3-3), and focusing mechanism mounting base (3-3-5) are all made of aluminum alloy with a black anodized surface. The focusing mechanism (3-3-4) is a one-dimensional lifting platform used to move the MW focusing spherical lens (3-3-1) in one dimension along the central axis, with a range of ±6mm. The medium wave rear lens group (3-4) includes a first medium wave rear lens (3-4-1), a second medium wave rear lens (3-4-2), a third medium wave rear lens (3-4-3), a medium wave rear lens barrel (3-4-4), and a medium wave rear lens holder (3-4-5); the first medium wave rear lens (3-4-1), the second medium wave rear lens (3-4-2), and the third medium wave rear lens (3-4-3) are bonded to corresponding positions in the inner cavity of the medium wave rear lens barrel (3-4-4), and the bonding glue is low Warm silicone rubber; the outer side of the medium-wave rear lens barrel (3-4-4) is threaded and mounted on the medium-wave rear lens holder (3-4-5) via a threaded pair; all three medium-wave rear lenses are spherical mirrors made of single-crystal silicon, with an anti-reflection coating that transmits the medium-wave spectrum; the medium-wave rear lens barrel (3-4-4) and the medium-wave rear lens holder (3-4-5) are made of aluminum alloy with a black anodized surface; the medium-wave rear lens holder (3-4-5) is mounted on the lower plate (1-2) via four screws; The medium wave filter wheel assembly (3-5) includes a filter (3-5-1), a filter frame (3-5-2), a turntable (3-5-3), a motor (3-5-4), a gear pair (3-5-5), a bearing (3-5-6), and a medium wave filter wheel mounting seat (3-5-7); the filter (3-5-1) is bonded to the filter frame (3-5-2) with a low-temperature silicone rubber adhesive; the filter frame (3-5-2) is fixed by three screws. Fixed on the turntable (3-5-3); the gear pair (3-5-5) is mounted on the medium-wave filter wheel mounting base (3-5-7) through the bearing (3-5-6); the motor (3-5-4) drives the turntable (3-5-3) to rotate through the gear pair (3-5-5); the filter (3-5-1) is made of single crystal germanium, with a total of 5 pieces, mounted on the turntable (3-5-3), and each filter has a different film layer, used to transmit light in different spectral bands; The medium wave detector refrigerator assembly (3-6) includes a dewar (3-6-1), a refrigerator (3-6-2), and a medium wave detector refrigerator bracket (3-6-3); the medium wave detector refrigerator bracket (3-6-3) is made of aluminum alloy with a black anodized surface; the dewar (3-6-1) and the refrigerator (3-6-2) are installed on the bracket (3-6-3), and the bracket is installed on the lower layer plate (1-2) of the base plate; A medium wave folding mirror (3-2), a medium wave focusing lens group (3-3), a medium wave rear lens group (3-4), and a medium wave filter wheel assembly (3-5) are installed on the lower plate (1-2).

7. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 6, characterized in that: The two medium wave front lenses are bonded into the medium wave front lens barrel (3-1-3), and the bonding glue is low-temperature silicone rubber; the outer side of the medium wave front lens barrel (3-1-3) is processed with threads and is installed on the medium wave front lens bracket (3-1-4) through a thread pair; the first medium wave front lens (3-1-1) and the second medium wave front lens (3-1-2) are made of single crystal silicon, and the medium wave front lens barrel (3-1-3) and the medium wave front lens bracket (3-1-4) are made of aluminum alloy; the medium wave front lens bracket (3-1-4) is hoisted on the upper plate (1-1) by four screws.

8. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 1, characterized in that: The long-wave channel (4) comprises a long-wave focusing lens assembly (4-1), a long-wave folding mirror assembly (4-2), a long-wave lens assembly (4-3), a long-wave filter wheel assembly (4-4), and a long-wave detector refrigerator assembly (4-5); The long-wave focusing lens assembly (4-1) comprises a long-wave focusing lens (4-1-1), a long-wave focusing lens frame (4-1-2), a long-wave focusing lens bracket (4-1-3), a one-dimensional lifting platform (4-1-4), and a long-wave focusing lens base (4-1-5); the long-wave focusing lens (4-1-1) is a spherical mirror, fixedly connected to the long-wave focusing lens frame (4-1-2), and the bonding glue is low-temperature silicone rubber; the long-wave focusing lens The frame (4-1-2) is mounted on a long-wave focusing lens bracket (4-1-3); the long-wave focusing lens bracket (4-1-3) is mounted on a one-dimensional lifting platform (4-1-4); the lifting platform (4-1-4) is mounted on a long-wave focusing lens base (4-1-5); the long-wave focusing lens base (4-1-5) is mounted on a lower plate (1-2); the surface of the long-wave focusing lens (4-1-1) is coated with an anti-reflection film that transmits a long-wave spectrum; The long-wave fold mirror assembly (4-2) includes a long-wave fold mirror (4-2-1) and a long-wave fold mirror bracket (4-2-2); the number of the long-wave fold mirrors (4-2-1) is two, which are used to fold the light path and are installed on the long-wave fold mirror bracket (4-2-2) by three screws; the long-wave fold mirror bracket (4-2-2) is installed on the lower plate (1-2) by four screws; the surface of the long-wave fold mirror (4-2-1) is coated with an aluminum reflective film, and the surface of the long-wave fold mirror bracket (4-2-2) is black anodized; The long-wave lens assembly (4-3) includes a first long-wave lens (4-3-1), a second long-wave lens (4-3-2), a third long-wave lens (4-3-3), an inner lens barrel (4-3-4), an outer lens barrel (4-3-5), and a long-wave lens base (4-3-6); the first long-wave lens (4-3-1) is bonded to the inner side of the inner lens barrel (4-3-4) using low-temperature silicone rubber as the bonding glue; the second long-wave lens (4-3-2) and the third long-wave lens (4-3-3) are bonded to the inner side of the outer lens barrel (4-3-5) using low-temperature silicone rubber as the bonding glue; the openings at both ends of the inner lens barrel (4-3-4) are of different sizes, the side with the larger opening is processed with an internal thread, and the side with the larger opening of the outer lens barrel (4-3-5) is processed with an external thread that matches the same. The outer lens barrel (4-3-5) is fixed with an external thread on the outer side of the middle part, which cooperates with the internal thread of the long-wave lens base (4-3-6) and is fixed to the long-wave lens base (4-3-6) through the thread pair; the long-wave lens base (4-3-6) is installed on the lower plate (1-2) by four screws; the first long-wave lens (4-3-1), the second long-wave lens (4-3-2), and the third long-wave lens (4-3-3) are all made of single crystal germanium, and the surface is coated with an anti-reflection film that transmits the long-wave spectrum; the inner lens barrel (4-3-4), the outer lens barrel (4-3-5), and the long-wave lens base (4-3-6) are all made of aluminum alloy, and the surface is black anodized; the long-wave lens assembly (4-3) is hoisted and installed on the upper plate (1-1); The structures of the long-wave filter wheel assembly (4-4) and the medium-wave filter wheel assembly (3-5) are identical except that the surface film layer of the five filters is an anti-reflection film for increasing the transmittance of the long-wave spectrum; the long-wave focusing lens assembly (4-1), the long-wave folding mirror assembly (4-2), and the long-wave filter wheel assembly (4-4) are installed on the lower plate (1-2); The long-wave detector refrigerator assembly (4-5) comprises a Dewar assembly (4-5-1) and a refrigerator assembly (4-5-2), both of which are independently mounted on a vertical plate (1-3) of a base plate (1).

9. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 8, characterized in that: The long-wave focusing lens (4-1-1) is bonded to the long-wave focusing lens frame (4-1-2), and the bonding glue is low-temperature silicone rubber; the outer side of the long-wave focusing lens frame (4-1-2) is processed with threads and is installed on the long-wave focusing lens bracket (4-1-3) through a thread pair; the long-wave focusing lens bracket (4-1-3) is installed on the one-dimensional lifting platform (4-1-4) through four screws; the long-wave focusing lens base (4-1-5) is installed on the lower On the layer plate (1-2); the material of the long-wave focusing lens (4-1-1) is single crystal germanium, and the surface is coated with an anti-reflection film that transmits the long-wave spectrum; the long-wave focusing lens frame (4-1-2), the long-wave focusing lens bracket (4-1-3), and the long-wave focusing lens base (4-1-5) are all made of aluminum alloy, and the surface is black anodized; the one-dimensional lifting platform (4-1-4) drives the long-wave focusing lens (4-1-1) to move along the central axis, with a travel of ±6mm.

10. The lightweight, compact, athermal infrared high-sensitivity camera structure according to claim 1, characterized in that: The substrate (1) is made of aluminum alloy and is integrally formed by 3D printing, with a base frequency greater than 600 Hz; the medium-wave spectrum range is 3.7 μm to 4.8 μm, and the long-wave spectrum range is 8 μm to 12.5 μm.

Images