40-degree field-of-view visible light lens for low-altitude aerial photography

Abstract

A 40-degree field-of-view visible light lens for low-altitude aerial photography comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object side to an image side, the second lens has positive focal power, and the second lens and the first lens are arranged at an interval; the third lens has positive focal power, and the third lens and the second lens are arranged at an interval; the fourth lens has positive focal power, and the fourth lens and the third lens are arranged at an interval; the diaphragm and the fourth lens are arranged at an interval and the diaphragm is used for limiting the aperture of the light beam; the fifth lens has negative focal power, and the fifth lens and the diaphragm are arranged at an interval; the sixth lens has negative focal power, and the sixth lens and the fifth lens are arranged at an interval; the seventh lens has negative focal power, and the seventh lens and the sixth lens are arranged at an interval; the eighth lens has negative focal power, and the eighth lens and the seventh lens are arranged at an interval; and the ninth lens has negative focal power, and the ninth lens and the eighth lens are arranged at an interval. The lens is simple in structure, high in imaging transfer function and low in distortion, and the field of view is fixed below 40 degrees.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical lenses, and specifically relates to a visible light lens for low-altitude aerial photography, which is especially suitable for the field of low-altitude aerial mapping and reconnaissance of unmanned aerial vehicles, and can realize low-distortion aerial imaging under a 40° field of view. Background Art

[0002] The aviation field requires that the lens can clearly image ground targets at high altitudes, with constantly changing parameters such as ambient temperature and atmospheric pressure. When drones are used, the aerial mapping lens used by drones has strict requirements on imaging distortion, imaging transfer function and weight. In addition, drones should be able to adapt to all-weather imaging under complex climatic conditions, and can achieve consistent imaging in daytime, darkness, fog or rain, which directly affects the widespread use of drones.

[0003] At present, the optical design of aerial surveying and mapping lenses cannot meet actual needs, the degree of lens standardization is low, and it is impossible to select lenses in time according to different weather conditions. When using visible light band monitoring lenses, especially when the field of view is large, the image quality is generally poor, and the distortion, clarity, and saturation cannot meet the actual requirements of aerial ground photography. Utility Model Content

[0004] In view of this, the purpose of the utility model is to provide a 40° field of view visible light lens for low-altitude aerial photography. The lens has a simple structure, a fixed field of view of 40°, a high imaging transfer function and low distortion. Since its field of view is fixed at 40°, it can be disassembled and assembled on the drone at any time according to weather conditions as a standard lens. When the weather conditions are good and there are many colored targets on the ground, the visible light lens is assembled to achieve high-quality imaging under a 40° field of view. It meets the large field of view imaging requirements of aerial ground observation and aerial mapping.

[0005] To achieve the above objectives, the following technical solutions are adopted:

[0006] The utility model provides a 40° field of view visible light lens for low-altitude aerial photography, including the following components arranged in sequence from the object side to the image side:

[0007] A first lens having positive optical power;

[0008] a second lens having positive optical power and spaced apart from the first lens;

[0009] a third lens having positive refractive power and spaced apart from the second lens;

[0010] a fourth lens having positive refractive power and spaced apart from the third lens;

[0011] an aperture, which is spaced apart from the fourth lens and is used to limit the beam aperture;

[0012] A fifth lens having negative optical power and spaced apart from the aperture stop;

[0013] a sixth lens having negative optical power and spaced apart from the fifth lens;

[0014] a seventh lens having negative optical power and spaced apart from the sixth lens;

[0015] an eighth lens having negative optical power and spaced apart from the seventh lens;

[0016] The ninth lens has negative optical power and is spaced apart from the eighth lens.

[0017] Furthermore,

[0018] The first lens has a concave surface facing the image side and a convex surface facing the object side;

[0019] The second lens has a concave surface facing the image side and a flat surface facing the object side;

[0020] The third lens has a convex surface facing the image side and a concave surface facing the object side;

[0021] The fourth lens has a concave surface facing the image side and a convex surface facing the object side;

[0022] The fifth lens is a biconvex lens;

[0023] The sixth lens is a biconcave lens;

[0024] The seventh lens is a biconvex lens;

[0025] The eighth lens is a biconvex lens;

[0026] The ninth lens has a concave surface facing the image side and a convex surface facing the object side.

[0027] Furthermore, the material of the first lens is H-ZLAF4LA, the thickness is 20 mm, and the curvature radii of the front and rear surfaces of the first lens are 30.88 mm and 19.27 mm respectively.

[0028] Furthermore, the material of the second lens is H-FK71, the distance between the second lens and the first lens is 9.33 mm, the thickness is 3 mm, and the curvature radii of the front and rear surfaces of the second lens are -1666.06 mm and 20.37 mm respectively.

[0029] Furthermore, the material of the third lens is H-ZLAF68C, the distance between the third lens and the second lens is 7.88 mm, the thickness is 8 mm, and the curvature radii of the front and rear surfaces of the third lens are -37.76 mm and -33.73 mm respectively.

[0030] Furthermore, the material of the fourth lens is H-ZF88, the distance between the fourth lens and the third lens is 20.35 mm, the thickness is 3.5 mm, and the curvature radii of the front and rear surfaces of the fourth lens are 25.55 mm and 48.47 mm respectively.

[0031] Furthermore, the distance between the aperture stop and the fourth lens is 6.21 mm, and the distance between the aperture stop and the fifth lens is 4.50 mm.

[0032] Furthermore, the material of the fifth lens is H-ZPK1A, the thickness is 4 mm, and the curvature radii of the front and rear surfaces of the fifth lens are 47.03 mm and -27.27 mm respectively.

[0033] Furthermore, the sixth lens is made of H-ZF88, has a distance of 1.44 mm from the fifth lens, a thickness of 2 mm, and curvature radii of the front and rear surfaces of the sixth lens are -21.93 mm and 30.49 mm, respectively.

[0034] Furthermore, the seventh lens is made of H-FK71, the distance between the seventh lens and the sixth lens is 1.25 mm, the thickness is 5.5 mm, and the curvature radii of the front and rear surfaces of the seventh lens are 36.90 mm and -25.98 mm respectively.

[0035] Furthermore, the material of the eighth lens is H-ZF88, the distance between the eighth lens and the seventh lens is 17.43 mm, the thickness is 8 mm, and the curvature radii of the front and rear surfaces of the eighth lens are 79.39 mm and -162.71 mm respectively.

[0036] Furthermore, the ninth lens is made of H-ZF88, has a distance of 0.2 mm from the eighth lens, a thickness of 8 mm, a distance of 19.40 mm from the image plane, and curvature radii of the front and rear surfaces of the ninth lens are 41.85 mm and 68.04 mm, respectively.

[0037] The 40° field of view visible light lens for low-altitude aerial photography of the utility model can also include a lens barrel. There is no special restriction on the lens barrel, and it can fix the above-mentioned first lens, second lens, third lens, fourth lens, aperture, fifth lens, sixth lens, seventh lens, eighth lens and ninth lens.

[0038] Compared with the prior art, the beneficial effects of the utility model are:

[0039] The utility model has a 40° field of view visible light lens for low-altitude aerial photography, which has a simple structure, a fixed viewing angle of 40°, a high imaging transfer function, low distortion, and good uniformity. It can achieve full-field MTF>0.6@50lp / mm, full-field maximum distortion<3%, illumination full-field uniformity better than 90%, and full-field point diagram RMS radius ≤5μm. It meets the imaging requirements of low-altitude aerial photography, especially for aerial mapping of ground color targets and other application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 This is a schematic diagram of the structure of a 40° field of view visible light lens for low-altitude aerial photography of the utility model;

[0042] In the figure, 1 is the first lens, 2 is the second lens, 3 is the third lens, 4 is the fourth lens, 5 is the aperture, 6 is the fifth lens, 7 is the sixth lens, 8 is the seventh lens, 9 is the eighth lens, and 10 is the ninth lens.

[0043] Figure 2 This is the full-field MTF diagram of the visible light lens in Example 1 of the utility model;

[0044] Figure 3 This is a diagram showing the maximum distortion of the entire field of view of the visible light lens in Example 1 of the utility model;

[0045] Figure 4 The uniformity of illumination over the entire field of view of the visible light lens in Example 1 of the utility model;

[0046] Figure 5 This is a full-field spot diagram of the visible light lens in Example 1 of the utility model. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0048] Example 1

[0049] The technical indicators of the optical lens are: size: φ54×150mm; wavelength range 0.45μm~0.89μm; back working distance: 19.4mm; maximum aperture of the lens: Full field MTF>0.6@50lp / mm, full field maximum distortion<3%; full field illumination uniformity better than 90%; full field point diagram RMS radius ≤5μm.

[0050] Based on the above technical indicators, the parameters of the designed optical lens and each optical element (radius, curvature, thickness, spacing, material, etc.) are shown in Table 1.

[0051] Table 1 Parameters of the optical elements of the optical lens of Example 1

[0052]

[0053]

[0054] After testing, the full-field MTF of the optical lens of Example 1 is as follows: Figure 2 As shown, the maximum distortion of the full field of view is Figure 3 As shown, the uniformity of illumination over the entire field of view is as follows Figure 4 As shown, the full field point diagram is as follows Figure 5 It can be seen that the optical lens of Example 1 has a high imaging transfer function, low distortion, good imaging clarity, good uniformity, and strong anti-interference ability.

[0055] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the embodiments. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. 40° field of view visible light lens for low altitude aerial photography, characterized by: Including the following arranged from the object side to the image side: A first lens (1) having positive optical power; a second lens (2) having positive optical power and spaced apart from the first lens (1); a third lens (3) having positive optical power and spaced apart from the second lens (2); a fourth lens (4) having positive refractive power and spaced apart from the third lens (3); An aperture (5) which is spaced apart from the fourth lens (4) and is used to limit the aperture of the light beam; a fifth lens (6) having negative optical power and spaced apart from the aperture stop (5); a sixth lens (7) having negative optical power and spaced apart from the fifth lens (6); a seventh lens (8) having negative optical power and spaced apart from the sixth lens (7); an eighth lens (9) having negative optical power and spaced apart from the seventh lens (8); The ninth lens (10) has negative optical power and is spaced apart from the eighth lens (9).

2. The 40° field of view visible light lens for low-altitude aerial photography according to claim 1, characterized in that: Including the following arranged from the image side to the object side: The first lens (1) has a concave surface facing the image side and a convex surface facing the object side; The second lens (2) has a concave surface facing the image side and a flat surface facing the object side; The third lens (3) has a convex surface facing the image side and a concave surface facing the object side; The fourth lens (4) has a concave surface facing the image side and a convex surface facing the object side; The fifth lens (6) is a biconvex lens; The sixth lens (7) is a biconcave lens; The seventh lens (8) is a biconvex lens; The eighth lens (9) is a biconvex lens; The ninth lens (10) has a concave surface facing the image side and a convex surface facing the object side.

3. The 40° field of view visible light lens for low-altitude aerial photography according to claim 1, characterized in that: The material of the first lens (1) is H-ZLAF4LA, with a thickness of 20 mm. The curvature radii of the front and rear surfaces of the first lens (1) are 30.88 mm and 19.27 mm respectively.

4. The 40° field of view visible light lens for low-altitude aerial photography according to claim 1, characterized in that: The material of the second lens (2) is H-FK71, the distance between the second lens (2) and the first lens (1) is 9.33 mm, the thickness is 3 mm, and the curvature radii of the front and rear surfaces of the second lens (2) are -1666.06 mm and 20.37 mm respectively.

5. The 40° field of view visible light lens for low-altitude aerial photography according to claim 1, characterized in that: The material of the third lens (3) is H-ZLAF68C, the distance between the third lens (3) and the second lens (2) is 7.88 mm, the thickness is 8 mm, and the curvature radii of the front and rear surfaces of the third lens (3) are -37.76 mm and -33.73 mm respectively.

6. The 40° field of view visible light lens for low-altitude aerial photography according to claim 1, characterized in that: The fourth lens (4) is made of H-ZF88, has a distance of 20.35 mm from the third lens (3), a thickness of 3.5 mm, and a curvature radius of the front and rear surfaces of the fourth lens (4) of 25.55 mm and 48.47 mm respectively; The distance between the aperture (5) and the fourth lens (4) is 6.21 mm, and the distance between the aperture (5) and the fifth lens (6) is 4.50 mm; The material of the fifth lens (6) is H-ZPK1A, the thickness is 4 mm, and the curvature radii of the front and rear surfaces of the fifth lens (6) are 47.03 mm and -27.27 mm respectively.

7. The 40° field of view visible light lens for low-altitude aerial photography according to claim 1, characterized in that: The sixth lens (7) is made of H-ZF88, has a distance of 1.44 mm from the fifth lens (6), a thickness of 2 mm, and a curvature radius of the front and rear surfaces of the sixth lens (7) of -21.93 mm and 30.49 mm respectively.

8. The 40° field of view visible light lens for low-altitude aerial photography according to claim 1, characterized in that: The seventh lens (8) is made of H-FK71, has a distance of 1.25 mm from the sixth lens (7), a thickness of 5.5 mm, and a curvature radius of the front and rear surfaces of the seventh lens (8) of 36.90 mm and -25.98 mm respectively.

9. The 40° field of view visible light lens for low altitude aerial photography according to claim 1, characterized in that: The eighth lens (9) is made of H-ZF88, has a distance of 17.43 mm from the seventh lens (8), a thickness of 8 mm, and a curvature radius of the front and rear surfaces of the eighth lens (9) of 79.39 mm and -162.71 mm respectively.

10. The 40° field of view visible light lens for low altitude aerial photography according to claim 1, characterized in that: The ninth lens (10) is made of H-ZF88, has a distance of 0.2 mm from the eighth lens (9), a thickness of 8 mm, a distance of 19.40 mm from the image plane, and curvature radii of the front and rear surfaces of the ninth lens (10) are 41.85 mm and 68.04 mm respectively.

Images