An infrared optical imaging system for an unmanned aerial vehicle

Abstract

The present invention discloses an infrared optical imaging system for an unmanned aerial vehicle, belonging to the field of unmanned aerial vehicles. The system includes an infrared optical imaging system arranged on the support of the unmanned aerial vehicle carrier. The system comprises a radome, a lens group and a detector. The radome is installed at the head of the unmanned aerial vehicle, and its front surface and rear surface are concentric spherical surfaces. The lens group includes a first lens, a second lens and a third lens which are arranged coaxially in sequence and are in a meniscus shape. The first lens and the third lens are positive lenses, and the second lens is a negative lens. The rear side surface of the first lens, the front side surfaces of the second lens and the third lens are all aspherical surfaces. The detector is located behind the lens group and receives the optimized infrared radiation for imaging. Through the material combination of single crystal silicon, single crystal germanium and chalcogenide glass IRG206, the passive thermal compensation structure, as well as the miniaturized and lightweight design, the present invention improves the target detection accuracy and equipment reliability in complex environments while reducing the cost.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicles, and particularly to an infrared optical imaging system for an unmanned aerial vehicle. Background Art

[0002] With the wide application of unmanned aerial vehicles in the fields of military reconnaissance, disaster monitoring, border patrol, and civilian logistics, the demand for high-precision target identification and real-time tracking capabilities is becoming increasingly urgent. As the core component for an unmanned aerial vehicle to perceive the environment, the infrared optical imaging system needs to maintain stable performance under complex electromagnetic interference, extreme temperature fluctuations, and high-speed maneuvering conditions. However, the existing infrared systems integrated into unmanned aerial vehicles have the following technical bottlenecks:

[0003] 1. Structural complexity and space occupancy issues:

[0004] Traditional infrared optical imaging systems mostly adopt a multi-lens group design (such as more than 5 lenses) and a secondary imaging architecture, resulting in a total system length exceeding 100 mm, making it difficult to adapt to the strict limitations of unmanned aerial vehicles on payload volume and weight. For example, if the volume of the infrared module in an unmanned aerial vehicle electro-optical pod is too large, the space of other sensors will be sacrificed, severely restricting the multi-task collaboration ability.

[0005] 2. Insufficient reliability in wide temperature environments:

[0006] The operating environment of unmanned aerial vehicles covers an extreme temperature range from -40°C to +60°C. Conventional infrared optical imaging systems rely on an active focusing mechanism to compensate for thermal defocus, which not only increases the system complexity, but also mechanical components such as motors and guide rails are prone to jamming in low-temperature environments, and the failure rate increases significantly. In addition, since the refractive index of the lens changes with temperature, the lens group is prone to deteriorate the system imaging quality in high and low temperature alternating scenarios.

[0007] 3. Assembly and adjustment efficiency and cost restrict large-scale applications:

[0008] Existing infrared systems often use diffractive surfaces or high-precision cemented lenses to improve imaging quality, but their assembly and adjustment rely on a high-precision optical platform and skilled technicians, and the assembly and adjustment of a single system takes a long time. The widespread use of expensive materials such as zinc selenide (ZnSe) has pushed up the manufacturing cost, making it difficult to meet the requirements of the civilian field for low-cost and mass production.

[0009] 4. Limited dynamic target tracking ability:

[0010] The tracking of high-speed maneuvering targets by unmanned aerial vehicles requires the optical imaging system to have fast response and field-of-view scanning capabilities. However, traditional fixed optical structures rely on the adjustment of the overall attitude of the vehicle, resulting in an increased target loss rate. When an unmanned aerial vehicle tracks a moving target object, if the field-of-view angle of the optical system is too small, it is necessary to frequently adjust the flight trajectory, seriously consuming the endurance time.

[0011] To address the above problems, the industry has tried to optimize by simplifying the optical structure or introducing new materials. However, most solutions are still limited to improving pure optical performance (such as resolution and transmittance), and have not fundamentally solved the core requirements of unmanned aerial vehicles for lightweight integration, environmental robustness, and rapid deployment. Therefore, there is an urgent need for an infrared optical imaging system designed specifically for unmanned aerial vehicles, which combines high performance and high reliability, to break through the existing technical bottlenecks and promote the practical application of unmanned platforms in complex scenarios. Summary of the Invention

[0012] The present invention provides an infrared optical imaging system for an unmanned aerial vehicle. Through miniaturization, lightweight, material innovation, and passive athermal design, it can reduce costs and significantly improve the target detection accuracy and equipment reliability in complex environments.

[0013] To achieve the above object, the technical solution adopted by the present invention is: an infrared optical imaging system for an unmanned aerial vehicle, including an infrared optical imaging system disposed on the support of the unmanned aerial vehicle carrier, and the infrared optical imaging system includes:

[0014] A radome, installed at the head of the unmanned aerial vehicle, the front surface and the rear surface of which are concentric spherical surfaces;

[0015] A lens group, disposed behind the radome, the lens group includes a first lens, a second lens, and a third lens that are arranged coaxially from front to back and are in the shape of a meniscus. Among them, the first lens and the third lens are positive lenses, the second lens is a negative lens, and the rear surface of the first lens, the second lens, and the front surface of the third lens are all aspherical surfaces;

[0016] A detector, disposed behind the lens group, and the infrared radiation transmitted through the lens group forms an image on the imaging surface of the detector;

[0017] The material of the radome is hot-pressed magnesium fluoride, the material of the first lens is single-crystalline silicon, the material of the second lens is single-crystalline germanium, and the material of the third lens is chalcogenide glass IRG206.

[0018] Further, the concave surfaces of the radome, the first lens, the second lens, and the third lens all face backward.

[0019] Preferably, the first lens, the second lens, and the third lens respectively satisfy the following conditions: 0.8 ≤ f1 / f ≤ 1.0, -0.7 ≤ f2 / f ≤ -0.5, 0.6 ≤ f3 / f ≤ 0.8, where f is the focal length of the infrared optical imaging system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f3 is the focal length of the third lens.

[0020] Preferably, the distance between the first lens and the second lens in the optical axis direction is T 23 , and the distance between the second lens and the third lens in the optical axis direction is T 34 , and the thickness of the second lens in the optical axis direction is CT 3, and satisfies the following relational expression: .

[0021] Furthermore, the whole fairing is a partial spherical structure, and its thickness is the difference between the front and rear surface curvature radii.

[0022] Furthermore, no diffractive surface is provided on all lenses in the lens group.

[0023] Furthermore, the fairing is fixedly arranged, and the lens group can rotate ±15° in both the azimuth direction and the pitch direction relative to the fairing.

[0024] Furthermore, the distance from the foremost end of the fairing to the imaging surface is 58 mm,

[0025] Furthermore, the distance between the rear surface of the third lens and the imaging surface in the optical axis direction is 6 mm.

[0026] Furthermore, the focal length of the infrared optical imaging system is 45 mm, the field of view is 12.2° × 9.8°, the imaging surface diameter is 12.4 mm, and the working band is 3 μm to 5 μm; F#: 2.0, where the F# calculation formula is f / D, f is the focal length of the infrared optical imaging system, and D is the entrance pupil diameter.

[0027] The beneficial effects of the present invention are:

[0028] (1) The infrared optical imaging system of the present invention realizes a miniaturized mid-wave infrared athermalized optical imaging system with a focal length of 45 mm, an imaging surface diameter of 12.4 mm, and a distortion less than 0.25% by optimizing the intervals between lenses, reasonably distributing the optical power, and cooperating with the lens optical materials. The total length of this system is 58 mm, and the back focal length is 6 mm, which is beneficial to the design of the rear-end detector installation structure.

[0029] (2) None of the lenses in the present invention use diffractive surfaces, thus avoiding energy loss caused by the diffraction efficiency of diffractive surfaces, improving the overall transmittance and imaging quality of the lens. At the same time, the requirements for the alignment accuracy of the infrared optical imaging system are reduced, the alignment efficiency is improved, which is beneficial to mass production.

[0030] (3) Through the synergistic cooperation among three different optical materials of single-crystalline silicon, single-crystalline germanium, and chalcogenide glass IRG206, the present invention realizes an optically passive athermalized optical imaging system that can achieve good imaging within a wide temperature range of -40°C to +60°C. There is no need to additionally set a focusing mechanism to compensate for the influence of temperature changes on imaging quality, simplifying the system structure and improving product reliability. Moreover, for lenses with a larger aperture, relatively low-cost single-crystalline silicon and chalcogenide glass IRG206 materials are used instead of expensive zinc selenide materials, effectively reducing the system cost. Brief Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the present invention applied to an unmanned aerial vehicle;

[0032] Figure 2 It is the optical path diagram of the infrared optical imaging system of the present invention;

[0033] Figure 3 It is the optical path diagram of the infrared optical imaging system of the present invention rotated by +15°;

[0034] Figure 4 It is the optical path diagram of the infrared optical imaging system of the present invention rotated by -15°;

[0035] Figure 5 It is the transfer function diagram of the infrared optical imaging system of the present invention at room temperature of 20°C;

[0036] Figure 6 It is the transfer function diagram of the infrared optical imaging system of the present invention at low temperature of -40°C;

[0037] Figure 7 It is the transfer function diagram of the infrared optical imaging system of the present invention at high temperature of +60°C;

[0038] Figure 8 It is the spot diagram of the infrared optical imaging system of the present invention at room temperature of 20°C;

[0039] Figure 9 It is the spot diagram of the infrared optical imaging system of the present invention at low temperature of -40°C;

[0040] Figure 10 It is the spot diagram of the infrared optical imaging system of the present invention at high temperature of +60°C;

[0041] Figure 11It is the field curvature and distortion curve graph of the infrared optical imaging system of the present invention;

[0042] Figure 12 It is the relative illuminance curve graph of the infrared optical imaging system of the present invention.

[0043] Among them, 100. Unmanned aerial vehicle; 200. Infrared optical imaging system; 1. Fairing; 2. First lens; 3. Second lens; 4. Third lens; 5. Protective glass for detector window; 6. Imaging surface. Specific embodiments

[0044] To make the above features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "rear", "left", "right", etc. indicating the orientation or positional relationship, it only corresponds to Figure 2 of the present application for the convenience of describing the present invention, and does not indicate or imply that the device or element referred to must have a specific orientation. The terms "first", "second", "third" are only used for descriptive purposes, referring to the order in which lenses of this type appear, and cannot be understood as indicating or implying relative importance.

[0045] Throughout the specification, the same reference numerals refer to the same elements. In the drawings, the drawings are only examples and are not drawn to scale strictly.

[0046] As common knowledge, the direction close to the object space is the object side, the direction close to the image space is the image side, and in the direction from the object side to the image side, the two surfaces of the lens are the incident surface and the exit surface in sequence. The object side refers to the side where light enters, the image side refers to the side where light exits, and "from front to back" is the direction from left to right in Figure 2 That is, the direction from the object side to the image side. Among the two surfaces of each lens, the surface facing the object side is called the object-side surface, and the surface facing the image side is called the image-side surface.

[0047] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0048] As Figures 1 to 4 shown, an infrared optical imaging system for an unmanned aerial vehicle includes an infrared optical imaging system 200 disposed on the carrier support of the unmanned aerial vehicle 100. The carrier support is disposed at a position near the head of the fuselage of the unmanned aerial vehicle 100 for carrying the infrared optical imaging system 200. The infrared optical imaging system 200 includes a fairing 1, a lens group, and a detector.

[0049] The front and rear surfaces of the fairing 1 are concentric spherical surfaces, and the fairing 1 is fixed to the head of the unmanned aerial vehicle 100. It adopts a partial spherical structure, and its thickness is the difference between the curvature radii of the front and rear surfaces. The curvature radius of the front surface is 105 mm, the curvature radius of the rear surface is 100 mm, and the thickness is 5 mm.

[0050] The lens group is arranged behind the fairing 1. The lens group includes a first lens 2, a second lens 3, and a third lens 4 that are arranged coaxially and are spaced apart from front to back in sequence. All three lenses are meniscus-shaped. The first lens 2 and the third lens 4 are positive lenses, and the second lens 3 is a negative lens. The rear side surface (image side surface) of the first lens 2, and the front side surfaces (object side surfaces) of the second lens 3 and the third lens 4 are aspherical surfaces. Moreover, the concave surfaces of the fairing 1, the first lens 2, the second lens 3, and the third lens 4 all face backward (image side), the curvature radius of each lens surface is positive, and no diffractive surface is provided for any lens in the lens group.

[0051] Preferably, the material of the fairing 1 is hot-pressed magnesium fluoride (MgF2), the material of the first lens 2 is single-crystal silicon (SILICON), the material of the second lens 3 is single-crystal germanium (Ge), and the material of the third lens 4 is chalcogenide glass IRG206.

[0052] The first lens 2 satisfies the following condition: 0.8 ≤ f 1 / f ≤ 1.0, where f is the focal length of the infrared optical imaging system, f 1 is the focal length of the first lens 2; the second lens 3 satisfies the following condition: -0.7 ≤ f 2 / f ≤ -0.5, where f is the focal length of the infrared optical imaging system, f 2 is the focal length of the second lens 3; the third lens 4 satisfies the following condition: 0.6 ≤ f 3 / f ≤ 0.8, where f is the focal length of the infrared optical imaging system, f 3 is the focal length of the third lens 4.

[0053] The distance between the first lens 2 and the second lens 3 in the optical axis direction is T 23 ; the distance between the second lens 3 and the third lens 4 in the optical axis direction is T 34 ; the thickness of the second lens in the optical axis direction is CT 3, and satisfies the following relational expression: .

[0054] The detector is located behind the lens group, and the infrared radiation transmitted through the lens group is imaged on the imaging surface 6 of the detector.

[0055] The distance from the foremost end of the radome to the imaging surface is 58 mm, the distance between the rear surface of the third lens and the imaging surface in the optical axis direction is 6 mm, and the diameter of the imaging surface is 12.4 mm.

[0056] The infrared optical imaging system further includes a swing mechanism. The radome 1 remains in a fixed state, and the swing mechanism is installed between the lens group and the radome 1. One end of the swing mechanism is firmly connected to the lens group, and the other end is reliably connected to the radome through a rotary joint or a similar structure to ensure structural stability and sealing. The swing mechanism is equipped with a dedicated driving device, which drives the lens group composed of the first lens 2, the second lens 3, and the third lens 4 and the detector to rotate ±15° in the azimuth direction and the pitch direction relative to the radome 1 according to the system control instructions. It should be noted that the swing mechanism is a common design in the art, and the specific structure will not be described in detail.

[0057] The light transmission path of the infrared optical imaging system of the present invention is that the light emitted by the infrared radiation of the external scene passes through the spherical radome 1 and reaches the first lens 2, converges after passing through the first lens 2 and reaches the second lens 3, diverges after passing through the second lens 3 and reaches the third lens 4, converges after passing through the third lens 4 and passes through the detector window protection glass 5 to be imaged on the image plane 6.

[0058] Table 1 shows the technical indicators achieved by the present invention, where F # (Infrared optical imaging system F number) The calculation formula is f / D , f is the focal length of the infrared optical imaging system, D is the diameter of the entrance pupil.

[0059] Table 1 Technical indicators of the infrared optical imaging system of the present invention

[0060]

[0061] Table 2 lists the detailed data of the infrared optical imaging system in this embodiment, which includes the surface type, radius of curvature, thickness, and material of each lens. The units of the radius of curvature and thickness of the lens are both mm, and the radius of curvature of the spherical and aspherical surfaces refers to the radius of curvature at the intersection of the lens surface and the optical axis. The "serial number" in Table 2 is counted along the direction of light propagation, such as the light beam incident surface of the fairing 1 is serial number S1, the light beam exit surface is serial number S2, and the serial numbers of other mirror surfaces are similar. The curved surfaces of the fairing 1, the first lens 2, the second lens 3, and the third lens 4 along the object side to the image side are marked as S1, S2, S3, S4, S5, S6, S7, and S8 respectively; "radius" represents the radius of curvature of the surface, and the principle for determining its positive and negative is: taking the intersection of the surface and the main optical axis as the starting point, the curved surface of the surface The center is taken as the end point. If the direction of the connecting line is the same as the direction of light propagation, it is positive, otherwise it is negative; if the surface is a plane, the radius of curvature of the surface is infinite; "Thickness" gives the distance between two adjacent surfaces on the optical axis. The principle of positive and negative judgment is: take the current surface vertex as the starting point and the next surface vertex as the end point. If the direction of the connecting line is the same as the direction of light propagation, it is positive, otherwise it is negative; if the material between the two surfaces is infrared material, the thickness represents the lens thickness, if there is no material between the two surfaces, it represents the air gap between the two lenses.

[0062] Table 2 Detailed data of the infrared optical imaging system in the embodiment of the present invention

[0063]

[0064] The surface of the first lens 2 facing the image side, i.e., the exit surface S4, the surface of the second lens 3 facing the object side, i.e., the incident surface S5, and the surface of the third lens 4 facing the object side, i.e., the incident surface S7, are all aspherical surfaces. The surface equations of the above-mentioned aspherical surfaces are:

[0065]

[0066] in, z (r) represents the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis. c is the curvature, c =1 / R , R represents the radius of curvature of the lens surface, r is the radial coordinate perpendicular to the optical axis, k is the quadratic constant, A is the fourth-order aspheric coefficient, B Sixth-order aspheric coefficients, C is the eighth-order aspheric coefficient, D is the tenth-order aspheric coefficient.

[0067] Table 3 lists the aspherical coefficients of the first lens 2 towards the image side surface, i.e., the exit surface S4, the second lens 3 towards the object side surface, i.e., the entrance surface S5, and the third lens 4 towards the object side surface, i.e., the entrance surface S7. The table uses scientific notation, for example, 8.1230e-006 represents 8.1230×10 -6 .

[0068] Table 3 Aspherical Coefficients of the Infrared Optical Imaging System in the Embodiment of the Invention

[0069]

[0070] After simulation by optical design software, when a mid-wave cooled detector with a pixel size of 15μm and a pixel number of 640×512 is selected, and the corresponding spatial frequency is 33 lp / mm, it can be seen from Figure 5 , Figure 6 , Figure 7 that under the conditions of normal temperature 20°C, low temperature -40°C, and high temperature +60°C, the transfer function of the infrared optical imaging system of the present invention is greater than 0.45. Observing the spot diagrams of the system shown in Figure 8 , Figure 9 , Figure 10 under the conditions of normal temperature 20°C, low temperature -40°C, and high temperature +60°C, it can be seen that the diameter of the blur spot is less than the diameter of the Airy disk in different focal length states of the system. From the field curvature and distortion curves of the infrared optical imaging system shown by Figure 11 , it can be seen that the distortion of the edge field of view of the system is less than 0.25%; from the relative illumination curve of Figure 12 , it can be known that the relative illumination of the edge field of view of the system is greater than 85%.

[0071] In summary, through a series of technological innovation points, the present invention significantly improves the performance and application potential of the infrared optical imaging system in the field of unmanned aerial vehicles, and has the following prominent advantages:

[0072] (1) Lightweight and miniaturized design

[0073] The present invention adopts a compact structure with only 3 lenses. The total length of the infrared optical imaging system is only 58mm. By optimizing the aspherical surface shape and the distance between the lenses, the overall volume and weight are effectively reduced. This design enables the infrared optical imaging system to be easily integrated into small unmanned aerial vehicles (such as multi-rotor or fixed-wing), avoiding occupying the installation space of other sensors, and providing strong support for the multi-functional integration of unmanned aerial vehicles.

[0074] (2) Passive athermalized material combination

[0075] The present invention cleverly combines single crystal silicon, single crystal germanium and chalcogenide glass IRG206, making full use of the differences in the thermal properties of these three materials, and successfully offsetting the impact of temperature changes on the infrared optical imaging system. Within a wide temperature range of -40°C to +60°C, the focal length change rate of the system is greatly reduced, and there is no need to set up a complex focusing mechanism. This not only avoids the risk of mechanical focusing components getting stuck in harsh environments, but also enables the system to operate stably in extremely harsh environments such as high altitudes and polar regions, improving the environmental adaptability and reliability of the system.

[0076] (3) Low-cost manufacturing and efficient assembly

[0077] In terms of material selection, the present invention uses relatively low-cost single crystal silicon and chalcogenide glass IRG206 to replace the expensive zinc selenide (ZnSe) in the traditional optical athermal system. At the same time, the process of directly machining aspheric surfaces with CNC machine tools avoids the complex diffraction surface process. These measures not only reduce material costs, but also greatly shorten the installation and adjustment time, improve production efficiency, and effectively promote the popularization and application of infrared optical imaging technology.

[0078] (4) High imaging quality and dynamic tracking capability

[0079] The present invention optimizes the optical path with the help of a unique aspheric design, which can accurately correct aberration problems such as spherical aberration, field curvature and distortion, effectively improving the imaging quality. At the same time, with the ±15° field of view swing scanning function, the attitude adjustment frequency of the drone when tracking the target is reduced, enabling it to quickly and accurately lock and track high-speed moving targets, enhancing the system's dynamic tracking capability.

[0080] In short, the present invention has achieved a comprehensive breakthrough in the performance, cost and reliability of infrared optical imaging systems through material innovation, structural optimization and process innovation. It has successfully solved the core problems of large volume, severe temperature drift and complex assembly and adjustment in the prior art, expanded its large-scale application potential in the civilian field, and provided key technical support for the efficient operation of unmanned aerial vehicles in scenarios such as smart cities, agricultural ecology, and emergency rescue. It has important practical significance and broad application prospects.

[0081] Finally, it should be noted that the parts of the present invention that are not described in detail are all prior art. Those of ordinary skill in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the aforementioned examples, those of ordinary skill in the art can still modify the technical solutions recorded in the aforementioned examples, or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, etc. made within the spirit and principles of the invention should be included in the scope of protection of the invention.

Claims

1. An infrared optical imaging system for an unmanned aerial vehicle, characterized in that, An infrared optical imaging system is provided on the support of an unmanned aerial vehicle carrier, and the infrared optical imaging system includes: A radome, installed at the head of the unmanned aerial vehicle, whose front surface and rear surface are concentric spherical surfaces; A lens group, arranged behind the radome. The lens group includes a first lens in the shape of a meniscus, a second lens in the shape of a meniscus, and a third lens in the shape of a meniscus, which are arranged coaxially from front to back in sequence. The number of lenses in the lens group is three. Among them, the first lens and the third lens are positive lenses, and the second lens is a negative lens. The rear surface of the first lens, the front surfaces of the second lens and the third lens are all aspherical surfaces. The first lens, the second lens and the third lens respectively satisfy the following conditions: 0.8 ≤ f1 / f ≤ 1.0, -0.7 ≤ f2 / f ≤ -0.5, 0.6 ≤ f3 / f ≤ 0.8, where f is the focal length of the infrared optical imaging system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f3 is the focal length of the third lens. No diffractive surface is provided on all the lenses in the lens group; A detector, arranged behind the lens group, and the infrared radiation transmitted through the lens group forms an image on the imaging surface of the detector; The material of the radome is hot-pressed magnesium fluoride, the material of the first lens is single-crystalline silicon, the material of the second lens is single-crystalline germanium, and the material of the third lens is chalcogenide glass IRG206. The focal length of the infrared optical imaging system is 45 mm, the field of view is 12.2°×9.8°, the diameter of the imaging surface is 12.4 mm, and the working band is 3 μm to 5 μm; F#: 2.0, where the F# calculation formula is f / D, f is the focal length of the infrared optical imaging system, and D is the diameter of the entrance pupil.

2. The infrared optical imaging system for an unmanned aerial vehicle according to claim 1, wherein, The concave surfaces of the radome, the first lens, the second lens and the third lens all face backward.

3. An infrared optical imaging system for an unmanned aerial vehicle according to claim 1 or 2, characterized in that, The distance between the first lens and the second lens in the optical axis direction is T 23 , the distance between the second lens and the third lens in the optical axis direction is T 34 , the thickness of the second lens in the optical axis direction is CT3, and the following relational expression is satisfied: 。 4. An infrared optical imaging system for an unmanned aerial vehicle according to claim 1, characterized in that, The radome as a whole is a partial spherical structure, and its thickness is the difference between the curvature radii of the front and rear surfaces.

5. An infrared optical imaging system for an unmanned aerial vehicle according to claim 1, characterized in that, The radome is fixedly arranged, and the lens group can rotate ±15° in both the azimuth direction and the pitch direction relative to the radome.

6. The infrared optical imaging system for an unmanned aerial vehicle according to claim 1, characterized in that, The distance from the front end of the radome to the imaging surface is 58 mm.

7. An infrared optical imaging system for an unmanned aerial vehicle according to claim 1, characterized in that, The distance between the rear surface of the third lens and the imaging surface in the optical axis direction is 6 mm.

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