High performance airborne head-mounted low-light-level night vision optical system

Abstract

The application relates to the technical field of optical design, in particular to a high-performance airborne head-mounted low-light-level night vision optical system which sequentially comprises a first positive lens, a first cemented component, a fourth positive lens, a fifth positive lens, a second cemented component and an eighth negative lens along an optical axis from an object side to an imaging surface; the first positive lens has positive focal power, the object side thereof is a convex surface, and the image side thereof is a concave surface; the object side of the first cemented component is a concave surface, and the image side thereof is a concave surface; the fourth positive lens has positive focal power, the object side thereof is a convex surface, and the image side thereof is a convex surface; the fifth positive lens has positive focal power, the object side thereof is a convex surface, and the image side thereof is a convex surface; the object side of the second cemented component is a concave surface, and the image side thereof is a convex surface; and the eighth negative lens has negative focal power, the object side thereof is a concave surface, and the image side thereof is a convex surface. The application has the advantages of a large relative aperture, low cost, good image quality, miniaturization and lightness, good thermal stability and normal operation at low and high temperatures.

Description

Technical Field

[0001] This invention relates to the field of optical design technology, and in particular to a high-performance airborne head-mounted low-light night vision optical system. Background Technology

[0002] Pilots need to take photos and videos frequently to identify objects in the air and on the ground while flying an aircraft. Especially in poor lighting conditions, low-light night vision optical systems can clearly capture videos and photos of the surrounding environment. This data allows pilots to accurately obtain information about the surrounding environment and make quick flight decisions, thereby avoiding accidents caused by inaccurate images.

[0003] The visible light spectrum for the human eye ranges from 380nm to 780nm. However, this wavelength is weaker at night, resulting in poor visibility. Therefore, sensors capable of sensing a wider wavelength range are needed to assist in this process. The near-infrared spectrum ranges from 780nm to 1100nm. To improve image quality and increase illumination on the image plane, a low-light sensor operating in the 400nm to 1100nm wavelength range is required to work with the optical system. To increase the amount of light entering the system, the relative aperture of the optical system must be large enough, and the corresponding F-number should be sufficiently small.

[0004] Pilots work in a unique environment. The aircraft cockpit contains numerous lighting and display devices. To minimize interference from these devices, the operating wavelength of the optical system must meet relevant standards, typically ranging from 600nm to 1000nm. To ensure pilots can observe objects at varying distances and avoid manual focusing, the imaging depth of the optical system is generally required to be between 2m and near infinity.

[0005] Using general optical lenses as airborne lenses has drawbacks. Because they are not specifically designed for low-light environments, images and videos suffer from insufficient brightness and poor image clarity in poorly lit conditions. Furthermore, general optical lenses are bulky and heavy, making them inconvenient to install on pilot helmets, which are already sensitive to weight. Airborne lenses also need excellent resistance to extreme temperatures, thus placing high demands on the selection of lens materials, requiring materials with a stable coefficient of thermal expansion.

[0006] Patent application number 202311104000.1 discloses a large-image-size low-light night vision lens, which adopts a design combining four glass lenses and four plastic aspherical lenses to achieve good image quality. However, the aspherical lens has a high processing cost, requires high installation accuracy, and the plastic lens has poor thermal stability.

[0007] Patent application number 202311105269.1 discloses a low-light night vision lens with a large field of view and a large relative aperture, which uses ten all-glass lenses to achieve an F-number of 1.4 and a full field of view of 67°. However, the total length reaches 111.5mm, the structure is not compact enough, and the cost of the optical system is high, making it not small and lightweight.

[0008] Existing patented lenses use a hybrid glass-plastic lens element. Using plastic lenses reduces the lens's thermal stability, and the use of aspherical lenses leads to high manufacturing costs and requires high mounting precision. Lenses with large relative apertures are characterized by their long structure, numerous lens elements, and lack of portability and compactness. Summary of the Invention

[0009] This invention provides a high-performance airborne head-mounted low-light night vision optical system to solve the technical problems mentioned in the background art.

[0010] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0011] This invention provides a high-performance airborne head-mounted low-light night vision optical system, comprising a first positive lens, a first cemented assembly, a fourth positive lens, a fifth positive lens, a second cemented assembly, and an eighth negative lens, arranged sequentially from the object side to the imaging plane:

[0012] A first positive lens with positive optical power, wherein the object side of the first positive lens is convex and the image side of the first positive lens is concave;

[0013] A first adhesive assembly with negative optical power, wherein the object side of the first adhesive assembly is concave and the image side of the first adhesive assembly is concave;

[0014] A fourth positive lens with positive optical power, wherein the object side of the fourth positive lens is convex and the image side of the fourth positive lens is convex;

[0015] A fifth positive lens with positive optical power, the object side of the fifth positive lens is convex, and the image side of the fifth positive lens is convex;

[0016] A second adhesive assembly with negative optical power, wherein the object side of the second adhesive assembly is concave and the image side of the second adhesive assembly is convex;

[0017] The eighth negative lens has negative optical power. The object side of the eighth negative lens is concave, and the image side is convex.

[0018] Further, the first adhesive assembly includes:

[0019] A second negative lens with negative optical power, wherein the object side of the second negative lens is concave and the image side is convex;

[0020] A third negative lens with negative optical power is provided. The object side of the third negative lens is conformal to the image side of the second negative lens and is bonded together with adhesive. The image side of the third negative lens is concave.

[0021] Furthermore, the thickness of the second negative lens is 0.998 mm; the optical power of the second negative lens is -0.012 mm. -1 The refractive index of the second negative lens is 1.66, and the Abbe number is between 57.34 and 57.35. The minimum air gap between the first positive lens and the second negative lens on the optical axis is 1.044 mm.

[0022] The thickness of the third negative lens is 1.047 mm, and the optical power of the third negative lens is -0.08 mm. -1 The refractive index of the third negative lens is 1.96, and the Abbe number is 17.47. The minimum air gap between the third negative lens and the fourth positive lens on the optical axis is 2.392 mm.

[0023] Further, the second adhesive assembly includes:

[0024] A sixth positive lens with negative optical power, the object side of the sixth positive lens is concave, and the image side of the sixth positive lens is convex;

[0025] The seventh negative lens has positive optical power. The object side of the seventh negative lens is conformal to the image side of the sixth positive lens and is bonded together with glue. The image side of the seventh negative lens is convex.

[0026] Furthermore, the thickness of the sixth positive lens is 3.656 mm, and the optical power of the sixth positive lens is 0.077 mm. -1 The sixth positive lens has a refractive index of 1.67 and an Abbe number of 51.74.

[0027] The thickness of the seventh negative lens is 3.134 mm, and the optical power of the seventh negative lens is -0.081 mm. -1 The seventh negative lens has a refractive index of 1.96 and an Abbe number of 17.47. The minimum air gap between the seventh and eighth negative lenses on the optical axis is 4.689 mm.

[0028] Furthermore, the surfaces of the first positive lens object side, the first positive lens image side, the second negative lens object side, the third negative lens image side, the fourth positive lens object side, the fourth positive lens image side, the fifth positive lens object side, the fifth positive lens image side, the sixth positive lens object side, the seventh negative lens image side, the eighth negative lens object side, and the eighth negative lens image side are all coated with anti-reflection and anti-reflection coatings, and their reflectivity is not greater than 0.5% when the wavelength is between 600nm and 1000nm.

[0029] Furthermore, it also includes a filter and an imaging surface arranged sequentially along the optical axis from the object side to the imaging surface;

[0030] The filter is disposed on one side of the image side of the eighth negative lens, and the filter thickness is 0.5 mm; the minimum air gap between the filter and the eighth negative lens on the optical axis is 0.1 mm; the minimum air gap between the filter and the imaging surface on the optical axis is 0.5 mm.

[0031] Furthermore, the optical power of the first positive lens is 0.049 mm. -1 The thickness of the first positive lens is 2.132 mm; the refractive index of the first positive lens is 2.05, and the Abbe number is 26.99.

[0032] The optical power of the fourth positive lens is 0.075mm. -1 The thickness of the fourth positive lens is 2.569 mm; the refractive index of the fourth positive lens is 1.88, and the Abbe number is 40.16.

[0033] The optical power of the fifth positive lens is 0.053mm. -1 The thickness of the fifth positive lens is 3.818 mm; the minimum air gap between the fourth and fifth positive lenses on the optical axis is 1.689 mm; the refractive index of the fifth positive lens is 2.05, and the Abbe number is 26.99.

[0034] The optical power of the eighth negative lens is -0.064mm. -1 The thickness of the eighth negative lens is 1.140 mm. The refractive index of the eighth negative lens is 1.69, and the Abbe number is 53.38.

[0035] Furthermore, the effective focal length of the first positive lens With the effective focal length of the optical system satisfy:

[0036] ;

[0037] And / or, the optical system satisfies the following condition:

[0038] ;

[0039] Wherein, R11 represents the radius of curvature of the object side of the first lens, R12 represents the radius of curvature of the image side of the first lens; and / or, the effective focal length of the optical system. radian of the maximum half field of view The true image height IH corresponding to the maximum field of view satisfies:

[0040] .

[0041] Furthermore, the distortion of the entire field of view of the optical system is less than 1.5%; the horizontal field of view of the optical system is not less than 40°, and the vertical field of view is not less than 30°.

[0042] The beneficial effects of this invention are:

[0043] 1. The high-performance airborne head-mounted low-light night vision optical system provided by this invention consists of eight lenses and one filter, all of which are ordinary spherical lenses, and all materials are domestically produced Chengdu Guangming Materials, resulting in low cost. Furthermore, the materials used are all low-expansion glass, providing excellent resistance to high and low temperatures.

[0044] 2. The high-performance airborne head-mounted low-light night vision optical system provided by this invention has an optical size of only φ16×30mm while achieving an F number of 1.4. This invention can ensure the amount of light intake while miniaturizing and light-reducing the size.

[0045] 3. The high-performance airborne head-mounted low-light night vision optical system provided by this invention supports the 600nm~1100nm low-light band, ensuring clear imaging in low-light environments. Maximum field-of-view distortion is less than 1.5%, ensuring sufficiently small deformation at the center and edges of the image field of view. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the present invention;

[0047] Figure 2 This is the optical path diagram of the present invention;

[0048] Figure 3 A dot diagram illustrating the high-performance airborne head-mounted low-light night vision optical system provided by this invention;

[0049] Figure 4 The optical modulation transfer function (MTF) curve of the high-performance airborne head-mounted low-light night vision optical system provided by this invention at room temperature (20°C);

[0050] Figure 5 The dot plot and optical modulation transfer function (MTF) curve of the high-performance airborne head-mounted low-light night vision optical system provided by the present invention at a high temperature of 70°C;

[0051] Figure 6 The dot plot and optical modulation transfer function (MTF) curve of the high-performance airborne head-mounted low-light night vision optical system provided by the present invention at a low temperature of -55°C;

[0052] Figure 7 This is the distortion-field diagram of the present invention;

[0053] Figure 8 This is a graph of the optical modulation transfer function (MTF) of the present invention at a working distance of 2 meters.

[0054] Explanation of reference numerals in the attached figures:

[0055] 1. First positive lens; 2. Second negative lens; 3. Third negative lens; 4. Fourth positive lens; 5. Fifth positive lens; 6. Sixth positive lens; 7. Seventh negative lens; 8. Eighth negative lens; 9. Filter; 10. Imaging plane;

[0056] S1, Object-side side of the first positive lens; S2, Image-side side of the first positive lens; S3, Object-side side of the second negative lens; S4, Image-side side of the second negative lens; S5, Image-side side of the third negative lens; S6, Object-side side of the fourth positive lens; S7, Image-side side of the fourth positive lens; S8, Object-side side of the fifth positive lens; S9, Image-side side of the fifth positive lens; S10, Object-side side of the sixth positive lens; S11, Image-side side of the sixth positive lens; S12, Image-side side of the seventh negative lens; S13, Object-side side of the eighth negative lens; S14, Image-side side of the eighth negative lens; S15, Object-side side of the filter; S16, Object-side side of the filter. Detailed Implementation

[0057] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many other different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0058] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0059] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0061] It should also be noted that in the embodiments of this application, the same reference numerals are used to represent the same component or part. For the same part in the embodiments of this application, the reference numerals may only be used to mark one part or component as an example in the figure. It should be understood that the reference numerals are also applicable to other identical parts or components.

[0062] Reference Figure 1 and Figure 2 This application provides a high-performance airborne head-mounted low-light night vision optical system, comprising a first positive lens 1, a first cemented assembly, a fourth positive lens 4, a fifth positive lens 5, a second cemented assembly, and an eighth negative lens 8, arranged sequentially from the object side to the imaging plane:

[0063] A first positive lens 1 with positive optical power, wherein the object side S1 of the first positive lens is convex and the image side S2 of the first positive lens is concave;

[0064] A first adhesive assembly with negative optical power, wherein the object side of the first adhesive assembly is concave and the image side of the first adhesive assembly is concave;

[0065] The fourth positive lens 4 has positive optical power, the object side S6 of the fourth positive lens is convex, and the image side S7 of the fourth positive lens is convex.

[0066] The fifth positive lens 5 has positive optical power, the object side S8 of the fifth positive lens is convex, and the image side S9 of the fifth positive lens is convex.

[0067] A second adhesive assembly with negative optical power, wherein the object side of the second adhesive assembly is concave and the image side of the second adhesive assembly is convex;

[0068] The eighth negative lens 8 has negative optical power. The object side S13 of the eighth negative lens is concave, and the image side S14 of the eighth negative lens is convex.

[0069] All the aforementioned lenses achieve good chromatic aberration and aberration correction effects through material matching, and the aperture stop is located on the surface of the object side S6 of the fourth positive lens.

[0070] In some embodiments, the first adhesive assembly includes:

[0071] The second negative lens 2 has negative optical power, the object side S3 of the second negative lens is concave, and the image side S4 of the second negative lens is convex.

[0072] The third negative lens 3 has negative optical power. The object side of the third negative lens and the image side S4 of the second negative lens are conformally shaped and bonded together with glue. The image side S5 of the third negative lens is concave.

[0073] In some embodiments, the thickness of the second negative lens 2 is 0.998 mm; the optical power of the second negative lens 2 is -0.012 mm. -1 The refractive index of the second negative lens 2 is 1.66, and the Abbe number is between 57.34 and 57.35. The minimum air gap between the first positive lens 1 and the second negative lens 2 on the optical axis is 1.044 mm.

[0074] The thickness of the third negative lens 3 is 1.047 mm, and the optical power of the third negative lens 3 is -0.08 mm. -1 The refractive index of the third negative lens 3 is 1.96, and the Abbe number is 17.47. The minimum air gap between the third negative lens 3 and the fourth positive lens 4 on the optical axis is 2.392 mm.

[0075] In some embodiments, the second adhesive assembly includes:

[0076] The sixth positive lens 6 has negative optical power. The object side surface S10 of the sixth positive lens is concave, and the image side surface S11 of the sixth positive lens is convex.

[0077] The seventh negative lens 7 has positive optical power. The object side of the seventh negative lens and the image side S11 of the sixth positive lens are conformally shaped and bonded together with glue. The image side S12 of the seventh negative lens is convex.

[0078] In some embodiments, the thickness of the sixth positive lens 6 is 3.656 mm, and the optical power of the sixth positive lens 6 is 0.077 mm. -1 The refractive index of the sixth positive lens 6 is 1.67, and the Abbe number is 51.74.

[0079] The thickness of the seventh negative lens 7 is 3.134 mm, and the optical power of the seventh negative lens 7 is -0.081 mm. -1 The refractive index of the seventh negative lens 7 is 1.96, and the Abbe number is 17.47. The minimum air gap between the seventh negative lens 7 and the eighth negative lens 8 on the optical axis is 4.689 mm.

[0080] In some embodiments, the surfaces of the first positive lens object-side surface S1, the first positive lens image-side surface S2, the second negative lens object-side surface S3, the third negative lens image-side surface S5, the fourth positive lens object-side surface S6, the fourth positive lens image-side surface S7, the fifth positive lens object-side surface S8, the fifth positive lens image-side surface S9, the sixth positive lens object-side surface S10, the seventh negative lens image-side surface S12, the eighth negative lens object-side surface S13, and the eighth negative lens image-side surface S14 are all coated with anti-reflection and anti-reflection coatings, and their reflectivity is not greater than 0.5% when the wavelength is between 600nm and 1000nm.

[0081] In some embodiments, a filter 9 and an imaging surface 10 are arranged sequentially along the optical axis from the object side to the imaging surface;

[0082] The filter 9 is disposed on the image-side surface S14 of the eighth negative lens, and the filter 9 has a thickness of 0.5 mm. The minimum air gap between the filter 9 and the eighth negative lens 8 on the optical axis is 0.1 mm. The minimum air gap between the filter 9 and the imaging surface 10 on the optical axis is 0.5 mm. The object-side surface S15 and the object-side surface S16 of the filter are both planar. The filter 9 is a flat glass plate and has no optical power.

[0083] In some embodiments, the optical power of the first positive lens 1 is 0.049 mm. -1 The thickness of the first positive lens 1 is 2.132 mm; the refractive index of the first positive lens 1 is 2.05, and the Abbe number is 26.99.

[0084] The optical power of the fourth positive lens 4 is 0.075mm. -1 The thickness of the fourth positive lens 4 is 2.569 mm; the refractive index of the fourth positive lens 4 is 1.88, and the Abbe number is 40.16.

[0085] The optical power of the fifth positive lens 5 is 0.053mm. -1 The thickness of the fifth positive lens 5 is 3.818 mm; the minimum air gap between the fourth positive lens 4 and the fifth positive lens 5 on the optical axis is 1.689 mm; the refractive index of the fifth positive lens 5 is 2.05 and the Abbe number is 26.99.

[0086] The optical power of the eighth negative lens 8 is -0.064mm. -1 The thickness of the eighth negative lens 8 is 1.140 mm. The refractive index of the eighth negative lens 8 is 1.69, and the Abbe number is 53.38.

[0087] In some embodiments, the distortion of the optical system across the entire field of view is less than 1.5%; the horizontal field of view of the optical system is not less than 40°, and the vertical field of view is not less than 30°.

[0088] In some embodiments, the effective focal length of the first positive lens 1 With the effective focal length of the optical system satisfy:

[0089] ;

[0090] By limiting the effective focal length, refractive index, and radius of curvature of the first positive lens 1, the deflection of large-angle light rays by the first lens 1 is controlled, which not only improves the brightness of the optical system, but also facilitates the subsequent lens group to correct aberrations in the optical system.

[0091] In some embodiments, the effective focal length of the first adhesive assembly With the effective focal length of the optical system satisfy:

[0092] ;

[0093] By limiting the effective focal length of the first bonded component and matching the refractive indices of the front and rear glass, it is beneficial to reduce aberrations such as spherical aberration, chromatic aberration, and distortion of the entire optical system, thereby improving the imaging quality of the optical system.

[0094] In some embodiments, the effective focal length of the fourth positive lens 4 With the effective focal length of the optical system satisfy:

[0095] ;

[0096] By limiting the effective focal length of the fourth positive lens 4, it is beneficial to reduce the overall aberration of the optical system and improve the imaging quality of the optical system.

[0097] In some embodiments, the effective focal length of the fifth positive lens 5 With the effective focal length of the optical system satisfy:

[0098] ;

[0099] By limiting the effective focal length of the fifth positive lens 5, it is beneficial to reduce the overall aberration of the optical system and improve the imaging quality of the optical system.

[0100] In some embodiments, the effective focal length of the second adhesive component With the effective focal length of the optical system satisfy:

[0101] ;

[0102] By limiting the effective focal length of the second cemented component and combining the positive and negative optical powers of the front and rear lens glass, the aperture stop is positioned between the first and second cemented components, forming a symmetrical deformed double Gaussian form with the first cemented component in the front group. This helps to reduce chromatic aberration and spherical aberration in the optical system and improve the imaging quality of the optical system.

[0103] In some embodiments, the effective focal length of the eighth negative lens 8 With the effective focal length of the optical system satisfy:

[0104] ;

[0105] By limiting the focal length of the eighth negative lens 8 and the effective focal length of the optical system, a lens with negative optical power can be used to effectively deflect the light from the optical system to the corresponding image plane height.

[0106] In some embodiments, the optical system satisfies the following condition:

[0107] ;

[0108] Wherein, R11 represents the radius of curvature of the object side surface S1 of the first positive lens, and R12 represents the radius of curvature of the image side surface S2 of the first positive lens.

[0109] By limiting the radius of curvature of the first positive lens 1 within a reasonable range, the machinability of the first positive lens 1 can be effectively guaranteed, the grinding yield of the first positive lens 1 can be increased, the processing cost can be reduced, and the aberration of the optical system can be reduced, thereby improving the performance quality.

[0110] In some embodiments, the optical system satisfies the following condition:

[0111] ;

[0112] Wherein, R41 represents the radius of curvature of the object side surface S6 of the fourth positive lens, and R42 represents the radius of curvature of the image side surface S7 of the fourth positive lens.

[0113] By limiting the radius of curvature of the fourth positive lens 4 within a reasonable range, the machinability of the fourth positive lens 4 can be effectively guaranteed, the grinding yield of the fourth positive lens 4 can be increased, the processing cost can be reduced, and the aberration of the airborne optical system can be reduced, thereby improving performance quality.

[0114] In some embodiments, the optical system satisfies the following condition:

[0115] ;

[0116] Wherein, R51 represents the radius of curvature of the object side surface S8 of the fifth positive lens, and R52 represents the radius of curvature of the image side surface S9 of the fifth positive lens.

[0117] By limiting the radius of curvature of the fifth positive lens 5 within a reasonable range, the machinability of the fifth positive lens 5 can be effectively guaranteed, the grinding yield of the fifth positive lens 5 can be increased, the processing cost can be reduced, and the aberration of the optical system can be reduced, thereby improving the performance quality.

[0118] In some embodiments, the optical system satisfies the following condition:

[0119] ;

[0120] Wherein, R81 represents the radius of curvature of the object side surface S13 of the eighth negative lens, and R82 represents the radius of curvature of the image side surface S14 of the eighth negative lens.

[0121] By limiting the radius of curvature of the eighth negative lens 8 to a reasonable range, the machinability of the eighth negative lens 8 can be effectively guaranteed, the grinding yield of the eighth negative lens 8 can be increased, and the processing cost can be reduced. On the other hand, the eighth negative lens 8, which adopts a meniscus shape, can also effectively deflect and focus light onto the imaging surface 10, ensuring that the effective image height is consistent with the actual target surface height.

[0122] In some embodiments, the effective focal length of the optical system radian of the maximum half field of view The true image height IH corresponding to the maximum field of view satisfies:

[0123] .

[0124] In some embodiments, the maximum field of view (FOV) of the optical system and the aperture value (FNO) of the optical system satisfy the following:

[0125] .

[0126] This ensures a wide field of view while maintaining a sufficiently large F-number, thereby guaranteeing the amount of light entering the entire optical system and improving the brightness of the imaging plane 10.

[0127] In some embodiments, the material of the first positive lens 1 is preferably optical glass H-ZLAF96; the material of the second negative lens 2 is preferably optical glass H-LAK1; the material of the third negative lens 3 is preferably optical glass H-ZF73; the material of the fourth positive lens 4 is preferably optical glass H-ZLAF73; the material of the fifth positive lens 5 is preferably optical glass H-ZLAF96; the material of the sixth positive lens 6 is preferably optical glass H-LAK67; the material of the seventh negative lens 7 is preferably optical glass H-ZF73; and the material of the eighth negative lens 8 is preferably optical glass H-LAK6A.

[0128] The high-performance airborne head-mounted low-light night vision optical system (hereinafter referred to as the optical system) provided by this invention operates in the 600~1100nm wavelength band, resulting in a focal length of 16.8mm, an F-number of 1.4, a horizontal full field of view of 40.56°, a vertical full field of view of 32.5°, and external dimensions of φ16×30mm. The high-performance airborne head-mounted low-light night vision optical system has advantages such as large relative aperture, low cost, good image quality, small size and lightweight design, and resistance to high and low temperatures.

[0129] Please refer to Figure 3The diagram shows the dot plot of the optical system of the present invention. It can be seen that the RMS of the dot plot in the entire field of view is less than 9.7 μm, and the GEO radius is less than 3 times the corresponding RMS radius. This indicates that the aberrations of the optical system are well corrected overall, and the image quality consistency between the center and the edge of the field of view is relatively good.

[0130] Please refer to Figure 4 The figure shows the optical modulation transfer function (MTF) curve of the optical system in this invention. It can be seen that the MTF curve of the entire field of view is relatively flat, and the imaging at various frequencies can be well taken into account. In the spatial frequency range within 52 lp / mm, the optical modulation transfer function of the entire field of view is higher than 0.4, which indicates that the optical system has good imaging quality in terms of low frequency profile, mid frequency level and high frequency detail.

[0131] It should be noted that the MTF (Modulation Tolerance) curve characterizes the relative change in modulation density with spatial frequency (line pairs per millimeter, unit: lp / mm) during imaging, and is often used to evaluate the resolution of imaging lenses. Figure 4 and Figure 5 As shown in the figure, the horizontal axis represents spatial frequency, and the vertical axis represents modulation degree (optical transfer function modulus).

[0132] Please refer to Figure 5 The figures show the dot plot and optical modulation transfer function (MTF) diagram of the optical system of the present invention at a high temperature of 70°C. Compared with the normal temperature, the size of the dot plot and the MTF optical modulation transfer function do not change significantly, which shows that the system has the ability to resist high temperature.

[0133] Please refer to Figure 6 The figures show the dot plot and optical modulation transfer function (MTF) plot of the optical system of the present invention at a low temperature of -55°C. Compared with room temperature, the dot plot did not change significantly, and the MTF optical modulation transfer function curve decreased by less than 0.1 at 52 lp / mm compared with room temperature.

[0134] Please refer to Figure 7 The image shows the distortion-field diagram of this invention. It can be seen that the distortion is controlled within 1.5% across the entire field of view.

[0135] Specifically, the design parameters of each lens in the optical system provided by the present invention are illustrated in Table 1. However, the design parameters of each lens are not limited to these. Other parameters in the data ranges mentioned above are also within the protection scope of the present invention. The parameters in Table 1 are for reference only.

[0136] Table 1: Preferred parameters of each lens in the optical system provided by the present invention;

[0137]

[0138] The high-performance airborne head-mounted low-light night vision optical system (hereinafter referred to as the optical system) provided by this invention consists of eight lenses and one filter, all of which are ordinary spherical lenses, and all materials are domestically produced Chengdu Guangming Materials, resulting in low cost. Furthermore, the materials used are all low-expansion glass, providing excellent resistance to high and low temperatures.

[0139] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-performance airborne head-mounted low-light night vision optical system, characterized in that, Composed of a first positive lens (1), a first cemented assembly, a fourth positive lens (4), a fifth positive lens (5), a second cemented assembly, and an eighth negative lens (8), the components are arranged sequentially from the object side to the imaging plane: A first positive lens (1) with positive optical power, wherein the object side (S1) of the first positive lens is convex and the image side (S2) of the first positive lens is concave; A first adhesive assembly with negative optical power, wherein the object side of the first adhesive assembly is concave and the image side of the first adhesive assembly is concave; The fourth positive lens (4) has positive optical power, the object side (S6) of the fourth positive lens is convex, and the image side (S7) of the fourth positive lens is convex; The fifth positive lens (5) has positive optical power, the object side (S8) of the fifth positive lens is convex, and the image side (S9) of the fifth positive lens is convex; A second adhesive assembly with negative optical power, wherein the object side of the second adhesive assembly is concave and the image side of the second adhesive assembly is convex; The eighth negative lens (8) has negative optical power. The object side (S13) of the eighth negative lens is concave, and the image side (S14) of the eighth negative lens is convex. The optical power of the first positive lens (1) is 0.049 mm. -1 The thickness of the first positive lens (1) is 2.132 mm; the refractive index of the first positive lens (1) is 2.05 and the Abbe number is 26.99; The optical power of the fourth positive lens (4) is 0.075 mm. -1 The thickness of the fourth positive lens (4) is 2.569 mm; the refractive index of the fourth positive lens (4) is 1.88 and the Abbe number is 40.16; The optical power of the fifth positive lens (5) is 0.053 mm. -1 The thickness of the fifth positive lens (5) is 3.818 mm; the minimum air gap between the fourth positive lens (4) and the fifth positive lens (5) on the optical axis is 1.689 mm; the refractive index of the fifth positive lens (5) is 2.05 and the Abbe number is 26.

99. The optical power of the eighth negative lens (8) is -0.064mm. -1 The thickness of the eighth negative lens (8) is 1.140 mm; the refractive index of the eighth negative lens (8) is 1.69 and the Abbe number is 53.

38.

2. The high-performance airborne head-mounted low-light night vision optical system according to claim 1, characterized in that, The first adhesive assembly includes: The second negative lens (2) has negative optical power, the object side (S3) of the second negative lens is concave, and the image side (S4) of the second negative lens is convex; A third negative lens (3) with negative optical power, the object side of the third negative lens and the image side of the second negative lens (S4) are conformal and bonded together with glue, and the image side of the third negative lens (S5) is concave.

3. The high-performance airborne head-mounted low-light night vision optical system according to claim 2, characterized in that, The thickness of the second negative lens (2) is 0.998 mm; the optical power of the second negative lens (2) is -0.012 mm. -1 The refractive index of the second negative lens (2) is 1.66, and the Abbe number is between 57.34 and 57.

35. The minimum air gap between the first positive lens (1) and the second negative lens (2) on the optical axis is 1.044 mm. The thickness of the third negative lens (3) is 1.047 mm, and the optical power of the third negative lens (3) is -0.08 mm. -1 The refractive index of the third negative lens (3) is 1.96 and the Abbe number is 17.

47. The minimum air gap between the third negative lens (3) and the fourth positive lens (4) on the optical axis is 2.392 mm.

4. The high-performance airborne head-mounted low-light night vision optical system according to claim 2, characterized in that, The second adhesive assembly includes: The sixth positive lens (6) has negative optical power, with the object side (S10) of the sixth positive lens being concave and the image side (S11) of the sixth positive lens being convex. The seventh negative lens (7) has positive optical power. The object side of the seventh negative lens and the image side of the sixth positive lens (S11) are conformal and bonded together with glue. The image side of the seventh negative lens (S12) is convex.

5. The high-performance airborne head-mounted low-light night vision optical system according to claim 4, characterized in that, The thickness of the sixth positive lens (6) is 3.656 mm, and the optical power of the sixth positive lens (6) is 0.077 mm. -1 The refractive index of the sixth positive lens (6) is 1.67 and the Abbe number is 51.

74. The thickness of the seventh negative lens (7) is 3.134 mm, and the optical power of the seventh negative lens (7) is -0.081 mm. -1 The refractive index of the seventh negative lens (7) is 1.96 and the Abbe number is 17.

47. The minimum air gap between the seventh negative lens (7) and the eighth negative lens (8) on the optical axis is 4.689 mm.

6. The high-performance airborne head-mounted low-light night vision optical system according to claim 4, characterized in that, The surfaces of the first positive lens object-side (S1), the first positive lens image-side (S2), the second negative lens object-side (S3), the third negative lens image-side (S5), the fourth positive lens object-side (S6), the fourth positive lens image-side (S7), the fifth positive lens object-side (S8), the fifth positive lens image-side (S9), the sixth positive lens object-side (S10), the seventh negative lens image-side (S12), the eighth negative lens object-side (S13), and the eighth negative lens image-side (S14) are all coated with anti-reflection and anti-reflection coatings, and their reflectivity is not greater than 0.5% when the wavelength is between 600nm and 1000nm.

7. The high-performance airborne head-mounted low-light night vision optical system according to claim 1, characterized in that, It also includes a filter (9) and an imaging surface (10) arranged sequentially along the optical axis from the object side to the imaging surface. The filter (9) is disposed on one side of the image side (S14) of the eighth negative lens, and the thickness of the filter (9) is 0.5 mm; the minimum air gap between the filter (9) and the eighth negative lens (8) on the optical axis is 0.1 mm; the minimum air gap between the filter (9) and the imaging surface (10) on the optical axis is 0.5 mm.

8. The high-performance airborne head-mounted low-light night vision optical system according to claim 1, characterized in that, The effective focal length of the first positive lens (1) With the effective focal length of the optical system satisfy: ； And / or, the optical system satisfies the following condition: ； Wherein, R11 represents the radius of curvature of the object side (S1) of the first positive lens, and R12 represents the radius of curvature of the image side (S2) of the first positive lens; And / or, the effective focal length of the optical system radian of the maximum half field of view The true image height IH corresponding to the maximum field of view satisfies: 。

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