A large-area, low-distortion telephoto lens for drones

Abstract

This invention discloses a large-area, low-distortion telephoto drone lens, consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and a filter, arranged sequentially from the object side to the image side. The aperture stop is located between the third and fourth lenses. A 50-megapixel all-glass, small-volume, large-area, low-distortion telephoto drone lens is proposed. This lens maintains stable image quality within a temperature range of -40℃ to 85℃ and also features 850nm infrared confocal focusing, enhancing the drone's ability to operate under complex lighting conditions.

Description

Technical Field

[0001] This invention relates to a large-area, low-distortion telephoto lens for drones, belonging to the field of lenses. Background Technology

[0002] With the rapid development of drones, higher demands are being placed on lens image quality and stability. They need to see far, see clearly, and maintain good image quality even in extreme weather conditions.

[0003] Current drone lenses still cannot simultaneously achieve a large target area, small size, and high stability, and their short focal length results in insufficient image quality. Summary of the Invention

[0004] In view of the shortcomings of existing technologies, the purpose of this invention is to provide a large-area, low-distortion telephoto drone lens to solve the problems.

[0005] To achieve the above objectives, the present invention provides a large-area, low-distortion telephoto lens for unmanned aerial vehicles, comprising: From the object side to the image side, the lenses are arranged in the following order: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, tenth lens, and filter. The aperture stop is located between the third lens and the fourth lens. The first lens has negative refractive power, the object side of the lens is convex, and the image side of the lens is concave. The second lens has positive refractive power, and the object-side surface of the lens is convex, while the image-side surface of the lens is concave. The third lens has positive refractive power, and its object-side surface is convex while its image-side surface is concave. The fourth lens has negative refractive power, and the object-side surface of the lens is concave, as is the image-side surface of the lens. The fifth lens has positive refractive power, and its object-side surface is convex while its image-side surface is concave. The sixth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens. The seventh lens has positive refractive power, and its object-side surface is convex while its image-side surface is concave. The eighth lens has negative refractive power, the object side of the lens is convex, and the image side of the lens is concave. The ninth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens. The tenth lens has negative refractive power. The object side of the lens is concave, and the image side of the lens is also concave. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are all glass spherical lenses; The first lens and the second lens are cemented doublet lenses; The fourth and fifth lenses are cemented doublet lenses; The seventh and eighth lenses are cemented doublet lenses; The ninth and tenth lenses are cemented doublet lenses.

[0006] Preferably, the refractive index nd6 of the sixth lens satisfies: nd6>1.90; the dispersion coefficients of the fourth, fifth, ninth, and tenth lenses satisfy the following relationship: vd5-vd6>35 and vd9-vd10>35; where vd5 is the dispersion coefficient of the fifth lens, vd6 is the dispersion coefficient of the sixth lens, vd9 is the dispersion coefficient of the ninth lens, and vd10 is the dispersion coefficient of the tenth lens.

[0007] Preferably, the drone lens meets the following requirements: First lens, 1.62 <nd<1.68,35<vd<45; Second lens, 1.65 <nd<1.75,25<vd<35; Third lens, 1.85 <nd<1.95,30<vd<42; Fourth lens, 1.75 <nd<1.88,23<vd<30; Fifth lens, 1.55 <nd<1.60,65<vd<77; Sixth lens, 1.90 <nd<2.10,15<vd<22; Seventh lens, 1.80 <nd<1.90,35<vd<45; Eighth lens, 1.75 <nd<1.82,20<vd<27; Ninth lens, 1.55 <nd<1.60,65<vd<75; Tenth lens, 1.80 <nd<1.88,19<vd<27; Where nd is the refractive index and vd is the dispersion coefficient.

[0008] Preferably, the ratio of the total length of the optical system of the drone lens to the focal length satisfies the following condition: 1.67 <TTL / F<2 Where TTL is the total length of the optical system of the UAV lens, and F is the focal length of the UAV lens.

[0009] Preferably, the drone lens satisfies the following condition: TTL≤76mm, F>40mm.

[0010] Preferably, the drone lens meets the following conditions: the visible light MTF is greater than 0.4 in the entire field of view at a frequency of 156 lp / mm, and greater than 0.5 in the 0.8 field of view.

[0011] Preferably, the drone lens meets the following conditions: the MTF is greater than 0.3 across the entire field of view at a frequency of 156 lp / mm, and greater than 0.4 within a field of view of 0.8.

[0012] Preferably, the drone lens meets the following condition: target surface height > 16.38 mm.

[0013] Preferably, the drone lens meets the following condition: the chromatic difference along the vertical axis is within 3µm.

[0014] Preferably, the drone lens meets the following condition: F-Tan distortion <2%.

[0015] Beneficial effects This invention proposes a 50-megapixel all-glass, small-volume, large-surface, low-distortion telephoto drone lens. The lens maintains stable image quality within a temperature range of -40℃ to 85℃ and features 850nm infrared confocal focusing, enhancing the drone's ability to operate under complex lighting conditions. Attached Figure Description

[0016] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of an example 1 of a large-area, low-distortion telephoto drone lens according to the present invention; Figure 2 For Example 1, the visible light MTF curve is greater than 0.4 across the entire field of view at a frequency of 156 lp / mm, and greater than 0.5 within a field of view of 0.8. Figure 3 For Example 1, the MTF curve at 850nm wavelength shows that it is greater than 0.3 across the entire field of view at a frequency of 156lp / mm, and greater than 0.4 within a field of view of 0.8. Figure 4 Example 1, chromatic aberration curve, lens chromatic aberration correction is less than 3µm; Figure 5 For Example 1, the Ray Fan curves show that the values ​​of each field of view are all within 15µm, and the blue-purple edge phenomenon is small. Figure 6 As shown in Example 1, the field curvature and distortion curves show that the distortion at each wavelength is less than 2%, and the image will not be affected by distortion. Detailed Implementation

[0017] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0018] Please see Figure 1-6 This invention provides a technical solution for a large-area, low-distortion telephoto drone lens, comprising: From the object side to the image side, the lenses are arranged in the following order: first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6, seventh lens 7, eighth lens 8, ninth lens 9, tenth lens 10, and filter 11. The aperture stop is located between the third lens 3 and the fourth lens 4. The first lens 1 has negative refractive power, the object side of the lens is convex, and the image side of the lens is concave. The second lens 2 has positive refractive power. The object side of the lens is convex, and the image side of the lens is concave. The third lens 3 has positive refractive power. The object side of the lens is convex, and the image side of the lens is concave. The fourth lens 4 has negative refractive power. The object side of the lens is concave, and the image side of the lens is also concave. The fifth lens 5 has positive refractive power. The object side of the lens is convex, and the image side of the lens is concave. The sixth lens 6 has positive refractive power. The object-side surface of the lens is convex, and the image-side surface of the lens is also convex. The seventh lens 7 has positive refractive power. The object-side surface of the lens is convex, and the image-side surface of the lens is concave. The eighth lens 8 has negative refractive power. The object side of the lens is convex, and the image side of the lens is concave. The ninth lens 9 has positive refractive power, and the object-side surface of the lens is convex, and the image-side surface of the lens is also convex. The tenth lens 10 has negative refractive power, and the object side of the lens is concave, and the image side of the lens is also concave.

[0019] To ensure the stability of the lens under extreme temperatures and to maintain high image quality, the first lens 1 to the tenth lens 10 are all glass spherical lenses.

[0020] To further optimize structural compactness and optical path performance, the first lens 1 and the second lens 2 are cemented together to form a cemented doublet lens; the fourth lens 4 and the fifth lens 5 are cemented together to form a cemented doublet lens; the seventh lens 7 and the eighth lens 8 are cemented together to form a cemented doublet lens; and the ninth lens 9 and the tenth lens 10 are cemented together to form a cemented doublet lens.

[0021] The refractive index nd6 of the sixth lens 6 satisfies: nd6 > 1.90; the Abbe numbers of the fourth lens 4, the fifth lens 5, the ninth lens 9, and the tenth lens 10 satisfy the following relationships: vd5 - vd6 > 35 and vd9 - vd10 > 35; where, vd5 is the Abbe number of the fifth lens 5, vd6 is the Abbe number of the sixth lens 6, vd9 is the Abbe number of the ninth lens 9, and vd10 is the Abbe number of the tenth lens 10.

[0022] In this embodiment, the optical parameters of the UAV lens satisfy the following conditions: For the first lens 1, 1.62 < nd < 1.68, 35 < vd < 45; For the second lens 2, 1.65 < nd < 1.75, 25 < vd < 35; For the third lens 3, 1.85 < nd < 1.95, 30 < vd < 42; For the fourth lens 4, 1.75 < nd < 1.88, 23 < vd < 30; For the fifth lens 5, 1.55 < nd < 1.60, 65 < vd < 77; For the sixth lens 6, 1.90 < nd < 2.10, 15 < vd < 22; For the seventh lens 7, 1.80 < nd < 1.90, 35 < vd < 45; For the eighth lens 8, 1.75 < nd < 1.82, 20 < vd < 27; For the ninth lens 9, 1.55 < nd < 1.60, 65 < vd < 75; For the tenth lens 10, 1.80 < nd < 1.88, 19 < vd < 27; Where, nd is the refractive index and vd is the Abbe number.

[0023] In terms of structural dimensions, the ratio of the total length (TTL) to the focal length (F) of the optical system of the UAV lens satisfies: 1.67 < TTL / F < 2. Preferably, TTL ≤ 76 mm and F > 40 mm.

[0024] Light rays are incident from the object plane and sequentially pass through the first lens 1 to the tenth lens 10 and the filter 11 and finally converge on the imaging plane. The present invention adopts a structural design of three lenses in the front group and seven lenses in the rear group, which effectively improves the image quality and reduces the outer diameter size while taking into account the large image plane and low distortion.

[0025] Specifically, by designing the first lens 1 and the second lens 2 as doublet lenses, the sensitivity of the front group is effectively reduced and the total length of the front group is shortened; by designing the fourth lens 4 and the fifth lens 5, the seventh lens 7 and the eighth lens 8, and the ninth lens 9 and the tenth lens 10 as doublet lenses respectively, the total length of the rear group is effectively shortened. In particular, the image sides of the fifth lens 5, the eighth lens 8, and the tenth lens 10 are set as concave surfaces, which is beneficial for the incident light beams of each field of view to be deflected and converged on the imaging surface after passing through the optical system, thereby enabling better suppression of spherical aberration, chromatic aberration, field curvature, and astigmatism of the optical system.

[0026] The aperture stop is located between the third lens 3 and the fourth lens 4, making the overall structural layout of the lens more reasonable. By adjusting the distance between the lens and the aperture stop, astigmatism can be corrected, and in particular, coma, distortion, and lateral aberration can be well corrected.

[0027] When the optical system satisfies 1.67 < TTL / F < 2, it can effectively control the volume of the optical system, ensure the advantage of small volume, and guarantee excellent imaging quality; it avoids the problem of reduced imaging quality caused by too small ratio or the problem of excessive volume and weight of the lens caused by too large ratio.

[0028] This lens has good stability within the extreme temperature range of -40°C to 85°C and has the following excellent performance: the visible light MTF is greater than 0.4 in the full field of view at a frequency of 156 lp / mm (greater than 0.5 within 0.8 field of view); the defocus amount of 850 nm infrared light is within 6 um, and the MTF performance is excellent; the target surface height > 16.38 mm, which can match a 1 / 0.98” 50M sensor; the lateral chromatic aberration is controlled within 3 um, and the F-Tan(Theta) distortion < 2%, and the imaging picture of this system will not be affected by distortion in terms of visual perception.

[0029] Now, a detailed description of the large target surface, low distortion, long focal length UAV lens according to each example will be given: For the optical structure of Example 1, please refer to Figure 1 , and the basic specifications of the UAV lens in this example are a focal length of 41.9, an F-number of 2.0, a total length ≤ 76 mm, and an image height > 16.38 mm. The specific parameters of this Example 1 are shown in Table 1 below:

[0030] Table 1 For the optical structure of Example 2, please refer to Figure 1 . The specific parameters of this Example 2 are shown in Table 2 below:

[0031] Table 2 For the optical structure of Example 3, please refer to Figure 1 . The specific parameters of this Example 2 are shown in Table 3 below:

[0032] Table 3 The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0033] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A large-area, low-distortion telephoto lens for unmanned aerial vehicles, characterized in that: include: From the object side to the image side, the lenses are arranged in the following order: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, tenth lens, and filter. The aperture stop is located between the third lens and the fourth lens. The first lens has negative refractive power, the object side of the lens is convex, and the image side of the lens is concave. The second lens has positive refractive power, and the object-side surface of the lens is convex, while the image-side surface of the lens is concave. The third lens has positive refractive power, and its object-side surface is convex while its image-side surface is concave. The fourth lens has negative refractive power, and the object-side surface of the lens is concave, as is the image-side surface of the lens. The fifth lens has positive refractive power, and its object-side surface is convex while its image-side surface is concave. The sixth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens. The seventh lens has positive refractive power, and its object-side surface is convex while its image-side surface is concave. The eighth lens has negative refractive power, the object side of the lens is convex, and the image side of the lens is concave. The ninth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens. The tenth lens has negative refractive power. The object side of the lens is concave, and the image side of the lens is also concave. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are all glass spherical lenses; The first lens and the second lens are cemented doublet lenses; The fourth and fifth lenses are cemented doublet lenses; The seventh and eighth lenses are cemented doublet lenses; The ninth and tenth lenses are cemented doublet lenses.

2. The large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 1, characterized in that: The refractive index nd6 of the sixth lens satisfies: nd6>1.90; the dispersion coefficients of the fourth, fifth, ninth, and tenth lenses satisfy the following relationship: vd5-vd6>35 and vd9-vd10>35; where vd5 is the dispersion coefficient of the fifth lens, vd6 is the dispersion coefficient of the sixth lens, vd9 is the dispersion coefficient of the ninth lens, and vd10 is the dispersion coefficient of the tenth lens.

3. The large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 2, characterized in that: The drone camera meets the following requirements: First lens, 1.62 <nd<1.68,35<vd<45; Second lens, 1.65 <nd<1.75,25<vd<35; Third lens, 1.85 <nd<1.95,30<vd<42; Fourth lens, 1.75 <nd<1.88,23<vd<30; Fifth lens, 1.55 <nd<1.60,65<vd<77; Sixth lens, 1.90 <nd<2.10,15<vd<22; Seventh lens, 1.80 <nd<1.90,35<vd<45; Eighth lens, 1.75 <nd<1.82,20<vd<27; Ninth lens, 1.55 <nd<1.60,65<vd<75; Tenth lens, 1.80 <nd<1.88,19<vd<27; Where nd is the refractive index and vd is the dispersion coefficient.

4. The large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 1, characterized in that: The ratio of the total length to the focal length of the optical system of a drone lens satisfies the following condition: 1.67 <TTL / F<2 Where TTL is the total length of the optical system of the UAV lens, and F is the focal length of the UAV lens.

5. A large-area, low-distortion telephoto drone lens according to claim 4, characterized in that: The drone lens must meet the following conditions: TTL≤76mm, F>40mm.

6. The large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 1, characterized in that: The drone lens meets the following conditions: the visible light MTF is greater than 0.4 in the entire field of view at a frequency of 156 lp / mm, and greater than 0.5 in the 0.8 field of view.

7. The large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 1, characterized in that: The drone lens meets the following conditions: the MTF is greater than 0.3 across the entire field of view at a frequency of 156 lp / mm, and greater than 0.4 within a field of view of 0.

8.

8. The large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 1, characterized in that: The drone lens must meet the following condition: target height > 16.38 mm.

9. A large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 1, characterized in that: The drone lens meets the following condition: the vertical chromatic difference is within 3um.

10. A large-area, low-distortion telephoto lens for unmanned aerial vehicles according to claim 1, characterized in that: The drone lens must meet the following condition: F-Tan distortion <2%.

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