Low-distortion unmanned aerial vehicle mapping lens with a shutter

Abstract

The application belongs to the technical field of unmanned aerial vehicle lenses, and particularly relates to a low-distortion shutter unmanned aerial vehicle surveying and mapping lens. The unmanned aerial vehicle surveying and mapping lens sequentially comprises a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a diaphragm group, a shutter group and a fourth lens group with positive optical power from an object side to an image side. The application has the advantages of less lens number, simple structure, low cost, easy assembly, low distortion and high precision, wherein the distortion is less than 0.02%. The shutter group is installed between the third lens and the fourth lens group, so that the weight and vibration are reduced, the precision of the unmanned aerial vehicle surveying and mapping lens is improved, and the endurance time of the unmanned aerial vehicle is ensured. The application can be applied to high and low temperature harsh working environments, and through the selection of materials and the optimization of structure, the application is suitable for working environments of-40 DEG C to +80 DEG C.

Description

Technical Field

[0001] This invention belongs to the technical field of drone lenses, specifically relating to a low-distortion drone mapping lens with shutter. Background Technology

[0002] Unmanned aerial vehicle (UAV) mapping is mainly used in national defense, forestry, urban planning, land registration, and water conservancy monitoring. UAVs operate in all seasons and regions, but the significant temperature differences between winter and summer in northern and southern regions necessitate lenses that remain in focus regardless of these conditions, as this affects image clarity. UAVs or other aircraft equipped with aerial cameras are used to map and create 3D models of the geographical environment or to analyze images. These cameras require lenses to obtain high-resolution, low-distortion images. Because of their application in geographical analysis and measurement, the requirements for lenses are extremely high. Lens resolution, distortion, chromatic aberration, operating environment, and weight directly affect the accuracy of the mapping and the aircraft's flight time.

[0003] For example, patent application number 202123182037.5 discloses a low-distortion aerial lens, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a lens barrel arranged coaxially. The first, second, third, fourth, and fifth lenses are sequentially fixed inside the lens barrel along the direction of light propagation. The first lens is a positive meniscus lens, the second lens is a negative meniscus lens, and the third lens is a negative meniscus lens. The adjacent surfaces of the first, second, and third lenses are fixed together to form a cemented lens. The fourth lens is a biconcave lens, and the fifth lens is a biconvex lens. The adjacent surfaces of the fourth and fifth lenses are fixed together to form a cemented lens. However, the distortion design value of this patent is 0.4%, and the aerial photography accuracy still needs improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a drone mapping lens that is simple in structure, has low distortion, reduces weight and vibration, has high precision, and is suitable for harsh working environments such as high and low temperatures. To achieve the purpose of this invention, the following technical solution is adopted:

[0005] A low-distortion drone mapping lens with shutter, the drone mapping lens comprising, from object side to image side, a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, an aperture group, a shutter group, and a fourth lens group with positive optical power.

[0006] A further improvement is that the fourth lens group is a bonded lens comprising a fourth lens with positive optical power and a fifth lens with negative optical power.

[0007] Further improvements are made in the following aspects:

[0008] The first lens is a negative lens, with a convex surface on the object plane side and a concave surface on the image plane side;

[0009] The second lens is a positive lens, with a convex surface on the object side and a concave surface on the image side;

[0010] The third lens is a positive lens, with a convex surface on the object side and a concave surface on the image side;

[0011] The fourth lens group is a positive lens, with a concave surface on the object plane side and a convex surface on the image plane side;

[0012] The fourth lens is a positive lens, with a concave surface on the object plane side and a convex surface on the image plane side;

[0013] The fifth lens is a negative lens, with a concave surface on the object plane and a convex surface on the image plane.

[0014] Further improvements are made in the following aspects:

[0015] The d-ray refractive index Nd1 and Abbe constant Vd1 of the first lens also satisfy the following conditions: 1.4 < Nd1 < 1.8, 10 < Vd1 < 50;

[0016] The d-ray refractive index Nd2 and Abbe constant Vd2 of the second lens also satisfy the following conditions: 1.6 < Nd2 < 1.9, 30 < Vd2 < 60;

[0017] The d-ray refractive index Nd3 and Abbe constant Vd3 of the third lens also satisfy the following conditions: 1.6 < Nd3 < 1.9, 10 < Vd3 < 60;

[0018] The d-ray refractive index Nd4 and Abbe constant Vd4 of the fourth lens also satisfy the following conditions: 1.6 < Nd4 < 1.9, 30 < Vd4 < 60;

[0019] The d-ray refractive index Nd5 and Abbe constant Vd5 of the fifth lens also satisfy the following conditions: 1.4 < Nd5 < 1.8, 10 < Vd5 < 60.

[0020] Further improvements are made in the following aspects:

[0021] The focal length f1 of the first lens also satisfies the following condition: -30 < f1 < -20;

[0022] The focal length f2 of the second lens also satisfies the following condition: 15 < f2 < 30;

[0023] The focal length f3 of the third lens also satisfies the following condition: 40 < f3 < 80;

[0024] The focal length f6 of the fourth lens group also satisfies the following condition: 20 < f6 < 40;

[0025] The focal length f4 of the fourth lens also satisfies the following condition: 5 < f4 < 15;

[0026] The focal length f5 of the fifth lens also satisfies the following condition: -10 < f5 < -20.

[0027] A further improvement is that the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all made of optical glass spherical surfaces.

[0028] A further improvement is that the aperture size of the shutter assembly is 4mm-8mm.

[0029] A further improvement is that the aperture F / NO of the UAV mapping lens satisfies the following condition: 4≤F / NO≤8.

[0030] A further improvement is that the half-image height Y of the UAV mapping lens satisfies the following condition: 10mm≤Y≤25mm.

[0031] A further improvement is that the focal length f of the UAV mapping lens satisfies the following condition: 20≤f≤50.

[0032] The beneficial effects of this invention are:

[0033] This invention utilizes fewer lenses, has a simple structure, low cost, and is easy to assemble, while also possessing the advantages of low distortion and high precision, with distortion less than 0.02%. By installing a shutter group between the third and fourth lens groups, this invention reduces weight and vibration, improves the accuracy of the UAV mapping lens, and ensures the UAV's flight time. This invention is suitable for harsh working environments with high and low temperatures; through material selection and structural optimization, it is applicable to working environments ranging from -40℃ to +80℃. Based on these characteristics, this invention has very promising application prospects. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the optical path structure of a low-distortion UAV mapping lens with shutter according to the present invention.

[0035] Figure 2 The distortion curve of a low-distortion drone mapping lens with shutter according to the present invention is shown.

[0036] Figure 3 This is a room temperature MTF curve of a low-distortion UAV mapping lens with shutter according to the present invention.

[0037] Figure 4 This is a low-distortion UAV mapping lens with shutter at -40 degrees Celsius, according to the present invention.

[0038] Figure 5This is a high-temperature 80-degree MTF curve of a low-distortion drone mapping lens with shutter according to the present invention.

[0039] Explanation of reference numerals in the attached diagram: L1, first lens; L2, second lens; L3, third lens; STO, aperture group; Shutter, shutter group; G1, fourth lens group; L4, fourth lens; L5, fifth lens. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this 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, and therefore should not be construed as a limitation of this invention.

[0044] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0045] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0046] Existing drone mapping lenses generally suffer from problems such as complex structure, large distortion, heavy weight, large vibration, low accuracy, inability to guarantee drone endurance, and unsuitability for harsh working environments with high and low temperatures. The purpose of this invention is to overcome at least one of the defects in the existing technology.

[0047] Please refer to the attached document. Figure 1 This invention proposes a low-distortion drone mapping lens with shutter, applicable to drone aerial mapping. The drone mapping lens, from object side to image side, includes, from left to right along the axis, a first lens L1 with negative optical power, a second lens L2 with positive optical power, a third lens L3 with positive optical power, an aperture group STO, a shutter group Shutter, and a fourth lens group G1 with positive optical power. The fourth lens group G1 is a bonded lens consisting of a fourth lens L4 with positive optical power and a fifth lens L5 with negative optical power.

[0048] In existing technologies, the shutter is generally designed near the camera's imaging chip. Since the dimensions of a full-frame sensor are 24x36, the aperture of the shutter, calculated using trigonometric functions, must be larger than 43.3mm to ensure that it does not block effective light. However, in this embodiment, the shutter group is designed in the middle of the lens. As can be seen from the optical path structure diagram of this embodiment, the aperture of the central aperture group STO is the smallest, with a diameter of only 5mm. Therefore, designing the shutter group in the middle of the lens can effectively reduce weight. Furthermore, due to its small diameter and size, it can effectively reduce vibration during shutter operation, thereby improving the accuracy of drone aerial surveying.

[0049] Furthermore, this embodiment adopts a 5-lens structure, which is lightweight and low-cost, and can effectively increase the drone's flight time while reducing weight.

[0050] In this embodiment, the five lenses are arranged coaxially, which makes it easier for the processing personnel to control the processing accuracy and ensures that the optical path coaxiality accuracy of the processed equipment is high, meeting the preset error allowable range. This is beneficial to improving the overall lens accuracy, thereby improving the accuracy and reliability of aerial surveying and mapping.

[0051] In this embodiment, as Figure 1 As shown, the first lens L1 is a negative lens, with a convex surface on the object plane side and a concave surface on the image plane side.

[0052] The second lens L2 is a positive lens, with a convex surface on the object side and a concave surface on the image side.

[0053] The third lens L3 is a positive lens, with a convex surface on the object plane and a concave surface on the image plane.

[0054] The fourth lens group G1 is a positive lens, with a concave surface on the object plane and a convex surface on the image plane.

[0055] The fourth lens L4 is a positive lens, with a concave surface on the object side and a convex surface on the image side.

[0056] The fifth lens L5 is a negative lens, with a concave surface on the object plane and a convex surface on the image plane.

[0057] The object side mentioned above refers to the surface closer to the object, while the image side refers to the surface closer to the imaging plane.

[0058] In this embodiment, the d-ray refractive index Nd1 and Abbe constant Vd1 of the first lens L1 also satisfy the following conditions: 1.4 < Nd1 < 1.8, 10 < Vd1 < 50.

[0059] The d-ray refractive index Nd2 and Abbe constant Vd2 of the second lens L2 also satisfy the following conditions: 1.6 < Nd2 < 1.9, 30 < Vd2 < 60.

[0060] The d-ray refractive index Nd3 and Abbe constant Vd3 of the third lens L3 also satisfy the following conditions: 1.6 < Nd3 < 1.9, 10 < Vd3 < 60.

[0061] The d-ray refractive index Nd4 and Abbe constant Vd4 of the fourth lens L4 also satisfy the following conditions: 1.6 < Nd4 < 1.9, 30 < Vd4 < 60.

[0062] The d-ray refractive index Nd5 and Abbe constant Vd5 of the fifth lens L5 also satisfy the following conditions: 1.4 < Nd5 < 1.8, 10 < Vd5 < 60.

[0063] In one embodiment of the present invention, the relevant parameters of each lens are shown in Table 1:

[0064]

[0065] Table 1

[0066] In this embodiment, the focal length f1 of the first lens L1 also satisfies the following condition: -30 < f1 < -20.

[0067] The focal length f2 of the second lens L2 also satisfies the following condition: 15 < f2 < 30.

[0068] The focal length f3 of the third lens L3 also satisfies the following condition: 40 < f3 < 80.

[0069] The focal length f6 of the fourth lens group G1 also satisfies the following condition: 20 < f6 < 40.

[0070] The focal length f4 of the fourth lens L4 also satisfies the following condition: 5 < f4 < 15.

[0071] The focal length f5 of the fifth lens L5 also satisfies the following condition: -10 < f5 < -20.

[0072] In this embodiment, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are all made of optical glass spherical surfaces. Using glass, compared to plastic, offers better thermo-optical stability, which helps improve the performance stability of the mapping lens and extend its service life.

[0073] In this embodiment, preferably, the aperture size of the shutter group is 4mm-8mm.

[0074] In this embodiment, preferably, the aperture F / NO of the UAV mapping lens satisfies the following condition: 4≤F / NO≤8.

[0075] In this embodiment, preferably, the half-image height Y of the UAV mapping lens satisfies the following condition: 10mm≤Y≤25mm.

[0076] In this embodiment, preferably, the focal length f of the UAV mapping lens satisfies the following condition: 20≤f≤50.

[0077] like Figure 2 As shown, the distortion curve of the UAV mapping lens in this invention is plotted through simulation analysis. The magnitude of distortion directly affects the mapping accuracy. The magnitude of distortion is expressed as a percentage. Figure 2 The distortion percentage is 0.02%. Low distortion improves the accuracy of surveying.

[0078] like Figure 3 As shown, the MTF curve of the UAV mapping lens in this invention at room temperature is plotted through simulation analysis, where MTF (Modulation Transfer Function) is the modulation transfer function. Figure 3 The image shows an MTF curve with 100 line pairs. Line pairs per millimeter usually refers to a resolution unit, indicating how many line pairs can be resolved within one millimeter. The more line pairs that can be resolved, the smaller the width of each line that can be resolved, and the better the resolution. Figure 4 This is a low-distortion UAV mapping lens with shutter at -40 degrees Celsius, according to the present invention. Figure 5 This is a high-temperature (80°C) MTF curve of a low-distortion UAV mapping lens with shutter according to the present invention. Figure 3 , Figure 4 , Figure 5 As shown, regardless of the temperature, whether it is room temperature, -40 degrees Celsius, or 80 degrees Celsius, the MTF curve of 100 line pairs is greater than 30%, indicating that the UAV mapping lens of the present invention has high resolution, good imaging quality, and is less affected by temperature.

[0079] This invention utilizes a small number of lenses, resulting in a simple structure, low cost, and easy assembly. It also boasts advantages such as low distortion and high precision, with distortion less than 0.02%. By installing a shutter group between the third lens L3 and the fourth lens group G1, this invention reduces weight and vibration, improves the accuracy of the UAV mapping lens, and ensures the UAV's flight time. Furthermore, this invention is suitable for harsh working environments, ranging from -40℃ to +80℃, thanks to material selection and structural optimization. Based on these characteristics, this invention has significant application potential.

[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A low-distortion, band-shuttered, unmanned aerial vehicle mapping lens, characterized by: The unmanned aerial vehicle mapping lens comprises, from the object side to the image side, a first lens with negative refractive power, a second lens with positive refractive power, a third lens with positive refractive power, a diaphragm group, a shutter group, a fourth lens group with positive refractive power; The fourth lens group is a bonded lens comprising a fourth lens with positive refractive power and a fifth lens with negative refractive power; The d-light refractive index Nd1 and the Abbe number Vd1 of the first lens also satisfy the following conditions: 1.4 < Nd1 < 1.8, 10 < Vd1 < 50; The d-light refractive index Nd2 and the Abbe number Vd2 of the second lens also satisfy the following conditions: 1.6 < Nd2 < 1.9, 30 < Vd2 < 60; The d-light refractive index Nd3 and the Abbe number Vd3 of the third lens also satisfy the following conditions: 1.6 < Nd3 < 1.9, 10 < Vd3 < 60; The d-light refractive index Nd4 and the Abbe number Vd4 of the fourth lens also satisfy the following conditions: 1.6 < Nd4 < 1.9, 30 < Vd4 < 60; The d-light refractive index Nd5 and the Abbe number Vd5 of the fifth lens also satisfy the following conditions: 1.4 < Nd5 < 1.8, 10 < Vd5 < 60.

2. The unmanned aerial vehicle mapping lens with low distortion and shutter according to claim 1, characterized in that: The first lens is a negative lens, the object side of the first lens is convex, and the image side is concave; The second lens is a positive lens, the object side of the second lens is convex, and the image side is concave; The third lens is a positive lens, the object side of the third lens is convex, and the image side is concave; The fourth lens group is a positive lens, the object side of the fourth lens group is concave, and the image side is convex; The fourth lens is a positive lens, the object side of the fourth lens is concave, and the image side is convex; The fifth lens is a negative lens, the object side of the fifth lens is concave, and the image side is convex.

3. The unmanned aerial vehicle mapping lens with low distortion and shutter according to claim 1, characterized in that: The focal length f1 of the first lens also satisfies the following condition: -30 < f1 < -20; The focal length f2 of the second lens also satisfies the following condition: 15 < f2 < 30; The focal length f3 of the third lens also satisfies the following condition: 40 < f3 < 80; The focal length f6 of the fourth lens group also satisfies the following condition: 20 < f6 < 40; The focal length f4 of the fourth lens also satisfies the following condition: 5 < f4 < 15; The focal length f5 of the fifth lens also satisfies the following condition: -10 < f5 < -20.

4. The low-distortion, push-broom, unmanned aerial vehicle mapping lens of claim 1, wherein: The first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all made of optical glass spherical surfaces.

5. The low-distortion, shuttered drone mapping lens of any of claims 1-4, wherein, The light aperture size of the shutter group is 4mm-8mm.

6. The low-distortion, shuttered drone mapping lens of any one of claims 1-4, wherein, The aperture F / NO of the unmanned aerial vehicle mapping lens satisfies the following condition: 4 ≤ F / NO ≤ 8.

7. The low-distortion, shuttered drone mapping lens of any one of claims 1-4, wherein, The half image height Y of the unmanned aerial vehicle mapping lens satisfies the following condition: 10mm ≤ Y ≤ 25mm.

8. The low-distortion, shuttered drone mapping lens of any one of claims 1-4, wherein, The focal length f of the unmanned aerial vehicle mapping lens satisfies the following condition: 20 ≤ f ≤ 50.

Images