Large-imaging aerial survey lens

Abstract

The invention provides a large-imaging aerial survey lens, and the lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from an object side to an imaging surface along an optical axis, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface and the image side surface of the third lens are concave surfaces; the object side surface and the image side surface of the fourth lens are convex surfaces; the object side surface and the image side surface of the fifth lens are convex surfaces; the object side surface and the image side surface of the sixth lens are concave surfaces; the object side surface of the seventh lens is a concave surface, and the image side surface of the seventh lens is a convex surface; the object side surface of the eighth lens is a concave surface, and the image side surface of the eighth lens is a convex surface; the object side surface of the ninth lens is a concave surface, and the image side surface of the ninth lens is a convex surface; a tenth lens; an eleventh lens; and a twelfth lens. According to the large-imaging aerial survey lens provided by the invention, the thirteen lenses are adopted to carry out spherical and aspheric combination, so that clear high-imaging quality is realized, and the phenomena of large distortion, large picture edge chromatic aberration and insufficient resolution are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of optical lenses, and in particular to a large imaging aerial survey lens. Background Art

[0002] Aerial survey lens is an aerial photography device formed by a combination of multiple lenses. It focuses and deflects light to achieve imaging of targets at near and far distances, and transmits the image to the ground to obtain specific pictures in aerial photography or photography during the flight.

[0003] Aerial survey lenses can be divided into half-frame (23.5mm×15.6mm), medium-frame (43.8mm×32.9mm) and full-frame cameras (36.0mm×24.0mm) according to the size of the sensor. In order to use cameras of the same specifications in different occasions, a camera with a sensor size of 53.3mm×40mm and a large imaging size has been launched to increase the photosensitive area and make the image clearer.

[0004] Aerial survey lenses are often installed on drones for aerial surveys, but traditional aerial survey lenses are only suitable for medium format cameras. Due to the limited imaging quality of medium format cameras, during fast or ultra-long-distance aerial photography, problems such as large distortion, large chromatic aberration at the edges of the frame, and insufficient resolution are common due to the influence of light or other factors, which in turn affect the accuracy of the aerial survey. Summary of the invention

[0005] The purpose of the present invention is to provide a large imaging aerial survey lens with a reasonable structure in view of the above problems in the prior art.

[0006] In order to achieve the above-mentioned object, the present invention can be implemented by the following technical solutions: A large imaging aerial survey lens, which includes, in sequence from the object side to the imaging surface along the optical axis:

[0007] The first lens has a flat object side and a concave image side;

[0008] The second lens has a convex object side surface and a concave image side surface;

[0009] The third lens has a concave surface on both the object side and the image side;

[0010] The fourth lens has a convex surface on both the object side and the image side;

[0011] The fifth lens has a convex surface on both the object side and the image side;

[0012] The sixth lens has a concave surface on both the object side and the image side;

[0013] The seventh lens has a concave object side and a convex image side;

[0014] The eighth lens has a concave object side and a convex image side;

[0015] The ninth lens has a concave object side and a convex image side;

[0016] A tenth lens, whose object side surface and image side surface are both convex;

[0017] An eleventh lens, whose object side surface is concave and whose image side surface is convex;

[0018] A twelfth lens, whose object side surface is concave and whose image side surface is convex;

[0019] The thirteenth lens has a convex object side and a concave image side;

[0020] The effective focal length f of the optical lens satisfies: 49.5<f<50.5, and the maximum field of view angle of the optical lens satisfies: 65°<FOV<69°.

[0021] In the embodiment of the present invention, the eleventh lens is an aspherical lens, and the thickness of the eleventh lens is 5.5 mm to 6 mm.

[0022] In the embodiment of the present invention, the third lens is glued to the fourth lens, the third lens is a negative lens, and its thickness is 1.3 mm to 1.9 mm, and the fourth lens is a positive lens, and its thickness is 4.2 mm to 4.8 mm.

[0023] In the embodiment of the present invention, the fifth lens is glued to the sixth lens, the fifth lens is a positive lens, and its thickness is 3.4 mm to 4 mm, and the sixth lens is a negative lens, and its thickness is 0.5 mm to 1 mm;

[0024] The seventh lens and the eighth lens are glued together, the thickness of the seventh lens is 4 mm to 4.5 mm, and the thickness of the eighth lens is 0.8 mm to 1.1 mm.

[0025] In the embodiment of the present invention, the interval between the sixth lens and the seventh lens is 6.5 mm to 7 mm.

[0026] In the embodiment of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are stacked one by one to form a focusing group;

[0027] The seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens and the twelfth lens are stacked one by one to form a diffusion group;

[0028] The thirteenth lens is a fixed group.

[0029] In the embodiment of the present invention, the radius of curvature of the object side of the first lens is 0, the radius of curvature of the image side of the first lens is 19±1mm, the radius of curvature of the object side of the second lens is 22±1mm, the radius of curvature of the image side of the second lens is 155±1mm, the radius of curvature of the object side of the third lens is -81±1mm, the radius of curvature of the image side of the third lens is 29±1mm, the radius of curvature of the object side of the fourth lens is 29±1mm, the radius of curvature of the image side of the fourth lens is -93±1mm, the radius of curvature of the object side of the fifth lens is 41±1mm, the radius of curvature of the image side of the fifth lens is 41±1mm, the radius of curvature of the object side of the sixth lens is 41±1mm, and the radius of curvature of the image side of the sixth lens is 54±1mm;

[0030] The first lens, the second lens, the third lens and the fourth lens are bonded together, and the fifth lens and the sixth lens are bonded together to form a focusing group, and the object side curvature radius of the focusing group is smaller than the object side curvature radius of the lens.

[0031] In this embodiment of the present invention, the radius of curvature of the object side of the seventh lens is 54±1mm, the radius of curvature of the image side of the seventh lens is -12±1mm, the radius of curvature of the object side of the eighth lens is 12±1mm, the radius of curvature of the image side of the eighth lens is -31±1mm, the radius of curvature of the object side of the ninth lens is -15±1mm, the radius of curvature of the image side of the ninth lens is -68±1mm, the radius of curvature of the object side of the tenth lens is 852±1mm, the radius of curvature of the image side of the tenth lens is -44±1mm, the radius of curvature of the object side of the eleventh lens is -28±1mm, the radius of curvature of the image side of the eleventh lens is -18±1mm, the radius of curvature of the object side of the twelfth lens is -20±1mm, and the radius of curvature of the image side of the twelfth lens is -34±1mm;

[0032] Among them, the seventh lens and the eighth lens are bonded together with the ninth lens, the tenth lens and the twelfth lens to form a spherical diffusion group, and the eleventh lens is an aspherical diffusion group, and the object side curvature radius of the spherical diffusion group is greater than the object side curvature radius of the lens.

[0033] In the embodiment of the present invention, the radius of curvature of the object side of the thirteenth lens is 113±1 mm, and the radius of curvature of the image side of the thirteenth lens is 1100±1 mm.

[0034] In the embodiment of the present invention, the refractive index of the first lens, the third lens, the seventh lens, the eighth lens, and the twelfth lens is 1.5<Nd<1.7;

[0035] The refractive index of the second lens, the fourth lens, the fifth lens, the sixth lens, the ninth lens, the tenth lens, the eleventh lens and the thirteenth lens is 1.7<Nd<1.9.

[0036] Compared with the prior art, the advantages of the present application are: simple structure, reasonable design, and the use of thirteen lenses in combination of spherical and aspherical surfaces to achieve clear and high-quality imaging, reduce large distortion, large chromatic aberration at the edge of the frame, and insufficient resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the lens combination and optical path structure in the aerial survey lens provided by an embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of the lens assembly in the aerial survey lens provided by an embodiment of the present invention;

[0039] Figure 3 is a schematic diagram of field curvature and distortion curves provided by an embodiment of the present invention;

[0040] Figure 4 is an MTF curve diagram provided by an embodiment of the present invention;

[0041] Figure 5 is a color difference curve diagram provided by an embodiment of the present invention.

[0042] Description of reference numerals:

[0043] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Ninth lens; 10. Tenth lens; 11. Eleventh lens; 12. Twelfth lens; 13. Thirteenth lens; 14. Optical axis. DETAILED DESCRIPTION

[0044] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention.

[0045] like Figure 1-5 As shown, a large imaging aerial survey lens includes, in sequence from the object side to the imaging surface along the optical axis 14:

[0046] A first lens 1, whose object side surface is a flat surface and whose image side surface is a concave surface;

[0047] The second lens 2 has a convex object side and a concave image side;

[0048] The third lens 3 has a concave surface on both the object side and the image side;

[0049] The fourth lens 4 has a convex surface on both the object side and the image side;

[0050] The fifth lens 5 has a convex surface on both the object side and the image side;

[0051] The sixth lens 6 has a concave surface on both the object side and the image side;

[0052] The seventh lens 7 has a concave object side surface and a convex image side surface;

[0053] The eighth lens 8 has a concave object side surface and a convex image side surface;

[0054] The ninth lens 9 has a concave object side surface and a convex image side surface;

[0055] The tenth lens 10 has a convex surface on both the object side and the image side;

[0056] The eleventh lens 11 has a concave object side surface and a convex image side surface;

[0057] The twelfth lens 12 has a concave object side surface and a convex image side surface;

[0058] The thirteenth lens 13 has a convex object side surface and a concave image side surface;

[0059] The effective focal length f of the optical lens satisfies: 49.5<f<50.5, and the maximum field of view angle of the optical lens satisfies: 65°<FOV<69°

[0060] Furthermore, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the twelfth lens 12 and the thirteenth lens 13 are all spherical lenses, and the eleventh lens 11 is an aspherical lens.

[0061] Specifically, Figure 2 As shown, the E end is the object side, and the F end is the image side. The aerial survey lens is composed of thirteen groups of lenses, and the thirteen groups of lenses are arranged in sequence along the direction of the optical axis 14. The first lens 1 is close to the E end (object side), and the thirteenth lens 13 is close to the F end (image side). The optical axis 14 is used to ensure the optical coaxiality of the thirteen groups of lenses to improve the aerial survey accuracy.

[0062] Further, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the twelfth lens 12 and the thirteenth lens are spherical lenses, and the eleventh lens 11 is an aspherical lens. The spherical lens is combined with the aspherical lens to condense or diffuse the light, reduce the distortion, spherical aberration, and chromatic aberration, so that the resolution of the lens is improved, and the picture is clearer and more accurate when the aerial survey lens is shooting or photographing. Among them, the thirteen lenses can be divided into ten groups, and the ten groups are specifically: the first lens 1, the second lens 2, the third lens 3 is bonded to the fourth lens 4, the fifth lens 5 is bonded to the sixth lens 6, the seventh lens 7 is bonded to the eighth lens 8, the ninth lens 9, the tenth lens 10, the twelfth lens 12 and the thirteenth lens, and an aperture is provided between the fourth group of lenses (the fifth lens 5 and the sixth lens 6 are bonded) and the fifth group of lenses (the seventh lens 7 and the eighth lens 8 are bonded) to limit the light beam or the size of the field of view (such as Figure 2 shown).

[0063] Furthermore, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, the twelfth lens 12 and the thirteenth lens 13 are all made of glass. The lenses can be made of glass, resin or PC (polycarbonate). The glass material improves the performance stability and service life of the aerial survey lens. Compared with resin lenses, glass lenses have better thermal-optical stability. For PC lenses, glass lenses have good dispersion control capabilities.

[0064] As an embodiment further provided by the present invention, the third lens 3 is glued to the fourth lens 4, the third lens 3 is a negative lens, and its thickness is 1.3mm to 1.9mm, and the fourth lens 4 is a positive lens, and its thickness is 4.2mm to 4.8mm.

[0065] Specifically, the third lens 3 is a low-refractive negative lens, and the fourth lens 4 is a high-refractive positive lens, and the two are bonded together by an adhesive to improve the light aggregation effect and eliminate the chromatic aberration caused by the front lens (the front lens is: the first lens 1 and the second lens 2).

[0066] As an embodiment further provided by the present invention, the fifth lens 5 and the sixth lens 6 are glued together, the fifth lens 5 is a positive lens, and its thickness is 3.4mm to 4mm, and the sixth lens 6 is a negative lens, and its thickness is 0.5mm to 1mm;.

[0067] Specifically, the fifth lens 5 is a high Abbe number positive lens, and the sixth lens 6 is a low Abbe number negative lens. The fifth lens 5 is connected to the sixth lens 6 by an adhesive to compress the system light to a minimum range. The fifth lens 5 and the sixth lens 6 form a fourth group of lenses, and the fourth group of lenses is close to the aperture.

[0068] As an embodiment further provided by the present invention, the seventh lens 7 and the eighth lens 8 are glued together, the thickness of the seventh lens 7 is 4 mm to 4.5 mm, and the thickness of the eighth lens 8 is 0.8 mm to 1.1 mm.

[0069] Specifically, the seventh lens 7 and the eighth lens 8 are both concave-convex lenses, which are connected by an adhesive to form a fifth group of lenses. Light begins to be diffused through the fifth group of lenses to meet the light coverage of the super-frame image surface, and the adhesive can be UV glue, low-temperature thermosetting glue and epoxy thermosetting glue.

[0070] As a further embodiment of the present invention, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are stacked one by one to form a focusing group;

[0071] The seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11 and the twelfth lens 12 are stacked one by one to form a diffusion group;

[0072] The thirteenth lens 13 is a fixed group.

[0073] Focusing group: The first lens 1 is a plano-concave negative lens, and the radius of curvature of the lens and the object side is 0, so as to initially compress a wide range of light and reduce the range of light;

[0074] The second lens 2 is a high refractive index negative lens, which further compresses the light and reduces its range;

[0075] The third lens 3 and the fourth lens 4 are glued together to continue to compress the light and eliminate the chromatic aberration caused by the first lens 1 and the second lens 2;

[0076] The fifth lens 5 and the sixth lens 6 are glued together to compress the light to the minimum range and refract it onto the aperture.

[0077] Diffusion group: The seventh lens 7 and the eighth lens 8 are bonded together to start receiving the light projected from the aperture and diffuse the light, thereby meeting the light coverage of the super-large image plane;

[0078] The ninth lens 9 is a high refractive index negative lens, which receives the light refracted by the seventh lens 7 and the eighth lens 8 and further diffuses the light;

[0079] The tenth lens 10 is a high refractive index positive lens, which further diffuses the light and preliminarily eliminates the distortion phenomenon;

[0080] The eleventh lens 11 is a high refractive index concave-convex glass aspherical lens, which diffuses the light while eliminating the distortion, spherical aberration and chromatic aberration produced by the front group;

[0081] The twelfth lens 12 is a concave-convex spherical lens with a large refractive power, which diffuses light to the greatest extent;

[0082] Fixed group: The thirteenth lens 13 is a high refractive index negative lens (refractive index is 1.9), which mainly produces a larger refraction angle and projects the light to the image plane, comprehensively optimizing the residual aberration produced by the front group.

[0083] As an embodiment further provided by the present invention, the object side curvature radius of the first lens 1 is 0, the image side curvature radius of the first lens 1 is 19±1mm, the object side curvature radius of the second lens 2 is 22±1mm, the image side curvature radius of the second lens 2 is 155±1mm, the object side curvature radius of the third lens 3 is -81±1mm, the image side curvature radius of the third lens 3 is 29±1mm, the object side curvature radius of the fourth lens 4 is 29±1mm, and the image side curvature radius of the fourth lens 4 is -93±1mm, The object side curvature radius of the fifth lens 5 is 41±1mm, the image side curvature radius of the fifth lens 5 is 41±1mm, the object side curvature radius of the sixth lens 6 is 41±1mm, and the image side curvature radius of the sixth lens 6 is 54±1mm. The first lens 1, the second lens 2, the third lens 3 and the fourth lens 4 are bonded, and the fifth lens 5 and the sixth lens 6 are bonded to form a focusing group, and the object side curvature radius of the focusing group is smaller than the object side curvature radius of the lens. The light is compressed and gathered through the focusing group to eliminate chromatic aberration.

[0084] As an embodiment further provided by the present invention, the seventh lens 7 has an object side curvature radius of 54±1mm, the seventh lens 7 has an image side curvature radius of -12±1mm, the eighth lens 8 has an object side curvature radius of 12±1mm, the eighth lens 8 has an image side curvature radius of -31±1mm, the ninth lens 9 has an object side curvature radius of -15±1mm, the ninth lens 9 has an image side curvature radius of -68±1mm, the tenth lens 10 has an object side curvature radius of 852±1mm, the tenth lens 10 has an image side curvature radius of -44±1mm, and the eleventh lens 11 has an object side curvature radius of -28± 1mm, the image side curvature radius of the eleventh lens 11 is -18±1mm, the object side curvature radius of the twelfth lens 12 is -20±1mm, the image side curvature radius of the twelfth lens 12 is -34±1mm, the seventh lens 7 and the eighth lens 8 are adhered, the ninth lens 9, the tenth lens 10 and the twelfth lens 12 are used to form a spherical diffusion group, and the eleventh lens 11 is an aspherical diffusion group. The object side curvature radius of the spherical diffusion group is greater than the object side curvature radius of the lens. The diffusion effect of light is improved by the diffusion group to meet the light coverage of the ultra-large image surface, while eliminating distortion, spherical aberration and chromatic aberration.

[0085] As an embodiment further provided by the present invention, the radius of curvature of the object side of the thirteenth lens 13 is 113±1 mm, the radius of curvature of the image side of the thirteenth lens 13 is 1100±1 mm, and the light is projected onto the image plane through the thirteenth lens 13.

[0086] As a further embodiment of the present invention, the refractive index of the first lens 1, the third lens 3, the seventh lens 7, the eighth lens 8, and the twelfth lens 12 is 1.5<Nd<1.7;

[0087] The refractive index of the second lens 2 , the fourth lens 4 , the fifth lens 5 , the sixth lens 6 , the ninth lens 9 , the tenth lens 10 , the eleventh lens 11 , and the thirteenth lens 13 is 1.7<Nd<1.9.

[0088] Table 1 shows the refractive index and radius of curvature of each lens.

[0089] Table 1:

[0090] Lens type Curvature 1 Curvature 2 Refractive index Nd The first lens Plano-concave lens flat 19.2 1.6 The second lens Concave and convex lenses 22 155 1.8 The third lens Concave-concave lens -81.7 29.5 1.6 The fourth lens Concave-convex lens 29.5 -93.6 1.8 The fifth lens Concave-convex lens 41.7 41.7 1.7 The sixth lens Concave-concave lens 41.7 54.2 1.7 The seventh lens Meniscus lens 54.4 -12 1.5 The eighth lens Meniscus lens 12 -31.1 1.6 The ninth lens Meniscus lens -15.1 -68.4 1.7 The tenth lens Concave-convex lens 852 -44.9 1.8 The eleventh lens Concave and convex aspheric lenses -28.8 -18.7 1.8 The twelfth lens Meniscus lens -20.4 -34.7 1.6 The thirteenth lens Concave and convex lenses 113.7 1100.6 1.9

[0091] As shown in the above table, the refractive index of the first lens 1, the third lens 3, the eighth lens 8 and the twelfth lens 12 is 1.6, the refractive index of the second lens 2, the fourth lens 4, the tenth lens 10 and the eleventh lens 11 is 1.8, the refractive index of the fifth lens 5, the sixth lens 6 and the ninth lens 9 is 1.7, the refractive index of the seventh lens 7 is 1.5, and the refractive index of the thirteenth lens 13 is 1.9.

[0092] In the present invention, the aerial survey lens is a lens with a larger imaging sensor size. The camera imaging sensor size is 53.3 mm×40 mm. Compared with traditional aerial survey lenses, the imaging area is larger to improve the operating efficiency of aerial survey. The effective focal length f of the aerial survey lens is 49.5<f<50.5, the maximum field of view FOV is 65°<FOV<69°, the total optical length TTL is 91<TTL<95, the aperture Fno. is 5.0<Fno.<6.0, and the main ray angle CRA is 16°<CRA<19°. The above data reflect that the aerial survey lens has high resolution, large imaging area and clear image.

[0093] As a further embodiment provided by the present invention, the design formula equation of the lens in the aerial survey lens is:

[0094]

[0095] Among them, the parameter CURV is the curvature corresponding to the radius, Y is the radial coordinate, and K is the coefficient of the conic quadratic curve; when K<-1, the lens surface curve is a hyperbola, when K=-1, the lens surface curve is a parabola; when -1<K<0, the lens surface curve is an ellipse, when K=0, the lens surface curve is a circle; when K>0, the lens surface curve is an oblate circle; A / B / C / D / E / F / G / H respectively represent the coefficients corresponding to each radial coordinate.

[0096] Table 2 shows the thickness of the lenses and the spacing between the lenses.

[0097] Table 2:

[0098]

[0099]

[0100] In the above Table 2, the third lens 3 and the fourth lens 4, the fifth lens 5 and the sixth lens 6, and the seventh lens 7 and the eighth lens 8 are all formed by gluing two lenses together, so the spacing between the three groups of glued lenses is 0, wherein the spacing between the sixth lens 6 and the seventh lens 7 is 6.5 mm to 7 mm, and an aperture is placed between the spacings, and the spacing between the thirteenth lens 13 and the image plane is 15.2 mm to 15.7 mm, which is the maximum spacing range of the aerial survey lens, thereby improving the clarity and range of imaging. Furthermore, the spacing ranges of the ten groups of lenses for aerial survey are different, and a slight spacing change will cause the optical performance of the camera to change. Therefore, the precise spacing range of the aerial survey lens can ensure the best imaging effect, and the specific functions generated by the spacing setting of each group of lenses in the lens are also different, such as the third group of lenses (the third lens 3 and the fourth lens 4 are glued together) is to eliminate chromatic aberration, the seventh group of lenses (the tenth lens 10) is to eliminate distortion, and the eighth group of lenses (the eleventh lens 11) is to further eliminate distortion and chromatic aberration.

[0101] The thickness of the lenses in the aerial survey lens reflects the refractive index of the lenses to adapt to the shooting needs and imaging effects of different occasions. The thickness ranges of each group of lenses are: the thickness range of the first lens 1 is 1.5mm to 2.1mm, the thickness range of the second lens 2 is 5.6mm to 6.2mm, the thickness range of the third lens 3 is 1.3mm to 1.9mm, the thickness range of the fourth lens 4 is 4.2mm to 4.8mm, the thickness range of the fifth lens 5 is 3.4mm to 4mm, the thickness range of the sixth lens 6 is 0.5mm to 1mm, the thickness range of the seventh lens 7 is 4mm to 4.5mm, the thickness range of the eighth lens 8 is 0.8mm to 1.1mm, and the thickness range of the ninth lens 9 is 1. The thickness range of the lens 9 is 1.2mm to 1.6mm, the thickness range of the tenth lens 10 is 4.2mm to 4.6mm, the thickness range of the eleventh lens 11 is 5.5mm to 6mm, the thickness range of the twelfth lens 12 is 1.5mm to 2.2mm, and the thickness range of the thirteenth lens 13 is 6.6mm to 7mm. The aerial survey lens is composed of thirteen lenses, and the thirteen lenses are divided into ten groups. The above sets the thickness and spacing range of each lens. The first lens 1 to the thirteenth lens 13 are placed one by one on the optical axis 14 according to the spacing range to combine into a large imaging aerial survey lens, so as to improve the accuracy and reliability of aerial survey and reduce distortion, chromatic aberration, insufficient resolution and other phenomena.

[0102] Figure 4 It is an MTF curve. The horizontal axis represents the distance between the edge of the lens and the imaging center, while the vertical axis represents the height of the contrast, that is, the imaging value of the lens. The closer to 1, the better the imaging value of the lens. The dotted lines on the vertical and horizontal axes are realized as line pairs. Multiple groups of line pairs are used to reflect the better the resolution and sharpness of the aerial survey lens, so that the imaging is clearer. Figure 5The chromatic aberration curve diagram shows that the lens has good dispersion and chromatic aberration control effects through the three curves in the chromatic aberration curve diagram to meet the needs of large imaging. If the chromatic aberration is poor, the image will be blurred at different positions. Therefore, aerial survey requires a higher chromatic aberration control effect. In the embodiment of the present invention, the eleventh lens 11 is an aspherical lens and is made of a refractive material. Therefore, it has a higher refractive index (refractive index is 1.8), which mainly eliminates distortion and chromatic aberration.

[0103] The technical solution of the present invention provides a solution that is significantly different from the prior art to address the technical problem that the prior art solution is too single. The parts not involved in the technical solution of this application are the same as the prior art or can be implemented by using the prior art and will not be described in detail.

[0104] The technical solutions in the above embodiments have clearly and completely described the contents of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A large imaging aerial survey lens, characterized in that: Along the optical axis from the object side to the imaging surface, it includes: The first lens has a flat object side and a concave image side; The second lens has a convex object side surface and a concave image side surface; The third lens has a concave surface on both the object side and the image side; The fourth lens has a convex surface on both the object side and the image side; The fifth lens has a convex surface on both the object side and the image side; The sixth lens has a concave surface on both the object side and the image side; The seventh lens has a concave object side and a convex image side; The eighth lens has a concave object side and a convex image side; The ninth lens has a concave object side and a convex image side; A tenth lens, whose object side surface and image side surface are both convex; An eleventh lens, whose object side surface is concave and whose image side surface is convex; A twelfth lens, whose object side surface is concave and whose image side surface is convex; The thirteenth lens has a convex object side and a concave image side; The effective focal length f of the optical lens satisfies: 49.5<f<50.5, and the maximum field of view angle of the optical lens satisfies: 65°<FOV<69°.

2. The large imaging aerial survey lens according to claim 1, characterized in that: The eleventh lens is an aspherical lens, and the thickness of the eleventh lens is 5.5 mm to 6 mm.

3. The large imaging aerial survey lens according to claim 1, characterized in that: The third lens is glued to the fourth lens, the third lens is a negative lens, and its thickness is 1.3mm to 1.9mm, and the fourth lens is a positive lens, and its thickness is 4.2mm to 4.8mm.

4. The large imaging aerial survey lens according to claim 1, characterized in that: The fifth lens is glued to the sixth lens, the fifth lens is a positive lens with a thickness of 3.4 mm to 4 mm, and the sixth lens is a negative lens with a thickness of 0.5 mm to 1 mm; The seventh lens and the eighth lens are glued together, the thickness of the seventh lens is 4 mm to 4.5 mm, and the thickness of the eighth lens is 0.8 mm to 1.1 mm.

5. The large imaging aerial survey lens according to claim 4, characterized in that: The distance between the sixth lens and the seventh lens is 6.5 mm to 7 mm.

6. The large imaging aerial survey lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are stacked one by one to form a focusing group; The seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens and the twelfth lens are stacked one by one to form a diffusion group; The thirteenth lens is a fixed group.

7. The large imaging aerial survey lens according to claim 6, characterized in that: The radius of curvature of the object side of the first lens is 0, the radius of curvature of the image side of the first lens is 19±1mm, the radius of curvature of the object side of the second lens is 22±1mm, the radius of curvature of the image side of the second lens is 155±1mm, the radius of curvature of the object side of the third lens is -81±1mm, the radius of curvature of the image side of the third lens is 29±1mm, the radius of curvature of the object side of the fourth lens is 29±1mm, the radius of curvature of the image side of the fourth lens is -93±1mm, the radius of curvature of the object side of the fifth lens is 41±1mm, the radius of curvature of the image side of the fifth lens is 41±1mm, the radius of curvature of the object side of the sixth lens is 41±1mm, and the radius of curvature of the image side of the sixth lens is 54±1mm; The first lens, the second lens, the third lens and the fourth lens are bonded together, and the fifth lens and the sixth lens are bonded together to form a focusing group, and the object side curvature radius of the focusing group is smaller than the object side curvature radius of the lens.

8. The large imaging aerial survey lens according to claim 6, characterized in that: The seventh lens has an object side curvature radius of 54±1mm, the seventh lens has an image side curvature radius of -12±1mm, the eighth lens has an object side curvature radius of 12±1mm, the eighth lens has an image side curvature radius of -31±1mm, the ninth lens has an object side curvature radius of -15±1mm, the ninth lens has an image side curvature radius of -68±1mm, the tenth lens has an object side curvature radius of 852±1mm, the tenth lens has an image side curvature radius of -44±1mm, the eleventh lens has an object side curvature radius of -28±1mm, the eleventh lens has an image side curvature radius of -18±1mm, the twelfth lens has an object side curvature radius of -20±1mm, and the twelfth lens has an image side curvature radius of -34±1mm; Among them, the seventh lens and the eighth lens are bonded together with the ninth lens, the tenth lens and the twelfth lens to form a spherical diffusion group, and the eleventh lens is an aspherical diffusion group, and the object side curvature radius of the spherical diffusion group is greater than the object side curvature radius of the lens.

9. The large imaging aerial survey lens according to claim 6, characterized in that: The radius of curvature of the object side of the thirteenth lens is 113±1 mm, and the radius of curvature of the image side of the thirteenth lens is 1100±1 mm.

10. The large imaging aerial survey lens according to claim 1, characterized in that: The refractive index of the first lens, the third lens, the seventh lens, the eighth lens and the twelfth lens is 1.5<Nd<1.7; The refractive index of the second lens, the fourth lens, the fifth lens, the sixth lens, the ninth lens, the tenth lens, the eleventh lens and the thirteenth lens is 1.7<Nd<1.9.

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