Medium format high definition aerial photography lens

Abstract

The utility model provides a medium format high-definition aerial camera lens, which relates to optical lens technology. The medium format high-definition aerial camera lens includes a first lens group, an aperture, a second lens group and a third lens group, which are arranged in sequence from the object side to the image side along the optical axis. The first lens group, the second lens group and the third lens group each include at least two lenses. The first lens group, the second lens group and the third lens group have positive optical power. An embodiment of the utility model provides a medium format high-definition aerial camera lens, which realizes an imaging target surface greater than 66mm, a pixel of more than 100 million pixels and effective correction of temperature drift by reasonably allocating optical power.

Description

Technical Field

[0001] The utility model relates to optical lens technology, in particular to a medium format high-definition aerial photography lens. Background Art

[0002] In recent years, with the rapid development of aerial photography applications, many domestic lens manufacturers have entered the aerial photography field and developed aerial lenses of various specifications, including 1-inch target surface, APS-C, full frame, etc., which are widely used in surveillance patrols, movie aerial photography, agricultural monitoring and other aerial photography fields.

[0003] However, for special fields such as high-precision geographic mapping and high-definition reconnaissance, larger imaging targets and higher-resolution aerial lenses are needed. Since such lenses have large imaging targets, high requirements for chromatic aberration correction and field curvature correction, and require high-resolution and clear imaging at ambient temperatures of -40℃ to 60℃, they are quite difficult to design and manufacture, and the price is high. Currently, there are basically no such lenses in China, and only a few foreign lens manufacturers have developed related lenses. Utility Model Content

[0004] The embodiment of the utility model provides a medium format high-definition aerial photography lens, which realizes an imaging target surface larger than 66mm, a pixel of more than 100 million pixels and an effective correction of temperature drift by reasonably allocating optical focal length.

[0005] The embodiment of the utility model provides a medium format high-definition aerial photography lens, comprising a first lens group, an aperture, a second lens group and a third lens group arranged in sequence from the object side to the image side along the optical axis; the first lens group, the second lens group and the third lens group each include at least two lenses;

[0006] The first lens group, the second lens group and the third lens group have positive refractive power.

[0007] Optionally, it is composed of 10 lenses;

[0008] The first lens group includes a first lens, a second lens and a third lens arranged in sequence from the object side to the image side along the optical axis, the second lens group includes a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side along the optical axis, and the third lens group includes a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object side to the image side along the optical axis.

[0009] Optionally, the first lens, the sixth lens, the seventh lens and the tenth lens are all meniscus lenses, and are all curved toward the aperture stop.

[0010] Optionally, the second lens, the fifth lens and the eighth lens are all biconvex lenses;

[0011] The third lens, the fourth lens and the ninth lens are all biconcave lenses.

[0012] Optionally, the second lens is glued to the third lens, the fourth lens is glued to the fifth lens, and the eighth lens is glued to the ninth lens.

[0013] Optionally, the first lens, the second lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens have positive optical power;

[0014] The third lens, the fourth lens, the ninth lens and the tenth lens have negative refractive power.

[0015] Optionally, the aperture is located between the third lens and the fourth lens.

[0016] Optionally, the first lens group, the aperture and the second lens group form a double Gaussian structure;

[0017] The total focal power of the first lens group and the second lens group is Φ12, and the focal power of the third lens group is Φ3, satisfying:

[0018] 1.5<Φ12 / Φ3<4.

[0019] Optionally, the distance from the aperture to the image plane of the medium format high-definition aerial photography lens is L, and the outer diameter of the image plane is D, which satisfies:

[0020] 0.45 <D / L<0.65。

[0021] In a medium format high-definition aerial photography lens provided by an embodiment of the utility model, the aperture is located between the first lens group and the second lens group. The first lens group has positive focal power, the second lens group has positive focal power, and the third lens group has positive focal power. By reasonably allocating the focal power, a medium format high-definition aerial photography lens with an imaging target surface larger than 66 mm, a pixel reaching more than 100 million pixels, and effective correction of temperature drift is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a medium format high definition aerial photography lens provided by an embodiment of the utility model;

[0023] Figure 2 This is a light path diagram of the medium-format high-definition aerial photography lens of Example 1;

[0024] Figure 3 This is the MTF curve of the medium format high definition aerial photography lens at 20°C in Example 1;

[0025] Figure 4This is the MTF curve of the medium format high definition aerial photography lens at -40°C in Example 1;

[0026] Figure 5 This is the MTF curve of the medium format high definition aerial photography lens at 60°C in Example 1;

[0027] Figure 6 This is a vertical axis chromatic aberration diagram of the medium format high definition aerial photography lens in Example 1;

[0028] Figure 7 This is a relative illumination diagram of a medium-format high-definition aerial camera lens in Example 1;

[0029] Figure 8 This is a field curvature distortion diagram of a medium-format high-definition aerial photography lens in Example 1;

[0030] Fig. 9 This is a light path diagram of the medium format high definition aerial photography lens of Example 2;

[0031] Fig.10 This is the MTF curve of the medium format high definition aerial photography lens at 20°C in Example 2;

[0032] Fig.11 This is the MTF curve of the medium format high definition aerial photography lens at -40°C in Example 2;

[0033] Fig.12 This is the MTF curve of the medium format high definition aerial photography lens at 60°C in Example 2;

[0034] Fig.13 This is a vertical axis chromatic aberration diagram of the medium format high definition aerial photography lens in Example 2;

[0035] Fig.14 This is a relative illumination diagram of a medium format high definition aerial camera lens in Example 2;

[0036] Fig.15 This is a field curvature distortion diagram of a medium format high definition aerial photography lens in Example 2;

[0037] Fig.16 This is a light path diagram of the medium format high definition aerial photography lens of Example 3;

[0038] Fig.17 This is the MTF curve of the medium format high definition aerial photography lens at 20°C in Example 3;

[0039] Fig.18 This is the MTF curve of the medium format high definition aerial photography lens at -40°C in Example 3;

[0040] Fig.19 This is the MTF curve of the medium format high definition aerial photography lens at 60°C in Example 3;

[0041] Fig. 20This is a vertical axis chromatic aberration diagram of the medium format high definition aerial photography lens in Example 3;

[0042] Fig.21 This is a relative illumination diagram of a medium-format high-definition aerial camera lens in Example 3;

[0043] Fig. 22 This is a field curvature distortion diagram of the medium format high definition aerial photography lens in Example 3. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0045] Figure 1 A schematic diagram of the structure of a medium format high definition aerial photography lens provided by an embodiment of the utility model, referring to Figure 1 The medium format high-definition aerial photography lens includes a first lens group G1, an aperture Stop, a second lens group G2, and a third lens group G3 arranged in sequence from the object side to the image side along the optical axis. The first lens group G1, the second lens group G2, and the third lens group G3 each include at least two lenses. The first lens group G1, the second lens group G2, and the third lens group G3 have positive refractive power.

[0046] In a medium format high-definition aerial photography lens provided by an embodiment of the utility model, the aperture Stop is located between the first lens group G1 and the second lens group G2. The first lens group G1 has positive focal power, the second lens group G2 has positive focal power, and the third lens group G3 has positive focal power. By reasonably allocating the focal power, a medium format high-definition aerial photography lens with an imaging target surface larger than 66 mm, a pixel of more than 100 million pixels, and effective correction of temperature drift is achieved.

[0047] For example, when the object distance is greater than or equal to 20 meters, the field curvature of the medium format high-definition aerial lens is within the aberration tolerance, and the back intercept is adjusted when the object distance changes to ensure clear imaging of the medium format high-definition aerial lens. When the object distance is less than 20 meters, the field curvature of the medium format high-definition aerial lens exceeds the aberration tolerance, and the field curvature of the medium format high-definition aerial lens is corrected by adjusting the distance between the first lens group G1 and the second lens group G2 to make it within the aberration tolerance, and then adjusting the back intercept of the medium format high-definition aerial lens to ensure clear imaging of the medium format high-definition aerial lens.

[0048] Optionally, refer to Figure 1, the medium format high-definition aerial lens consists of 10 lenses. The first lens group G1 includes the first lens L1, the second lens L2 and the third lens L3 arranged in sequence from the object side to the image side along the optical axis. The second lens group G2 includes the fourth lens L4, the fifth lens L5 and the sixth lens L6 arranged in sequence from the object side to the image side along the optical axis. The third lens group G3 includes the seventh lens L7, the eighth lens L8, the ninth lens L9 and the tenth lens L10 arranged in sequence from the object side to the image side along the optical axis. Thus, the 10 lenses are the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9 and the tenth lens L10 arranged in sequence from the object side to the image side along the optical axis.

[0049] Exemplarily, the aperture stop Stop is located between the third lens L3 and the fourth lens L4.

[0050] Optionally, refer to Figure 1 The first lens L1, the sixth lens L6, the seventh lens L7 and the tenth lens L10 are all meniscus lenses, and the first lens L1, the sixth lens L6, the seventh lens L7 and the tenth lens L10 are all curved toward the aperture Stop, thereby correcting the field curvature of the medium format high-definition aerial photography lens.

[0051] Exemplarily, the first lens L1 is a convex-concave lens, the object side surface of the first lens L1 is convex toward the object side, and the image side surface of the first lens L1 is convex toward the object side. The sixth lens L6 is a concave-convex lens, the object side surface of the sixth lens L6 is convex toward the image side, and the image side surface of the sixth lens L6 is convex toward the image side. The seventh lens L7 is a concave-convex lens, the object side surface of the seventh lens L7 is convex toward the image side, and the image side surface of the seventh lens L7 is convex toward the image side. The tenth lens L10 is a concave-convex lens, the object side surface of the tenth lens L10 is convex toward the image side, and the image side surface of the tenth lens L10 is convex toward the image side.

[0052] Optionally, refer to Figure 1 , the second lens L2, the fifth lens L5 and the eighth lens L8 are all biconvex lenses. The object side surface of the second lens L2 is convex toward the object side, and the image side surface of the second lens L2 is convex toward the image side. The object side surface of the fifth lens L5 is convex toward the object side, and the image side surface of the fifth lens L5 is convex toward the image side. The object side surface of the eighth lens L8 is convex toward the object side, and the image side surface of the eighth lens L8 is convex toward the image side. The third lens L3, the fourth lens L4 and the ninth lens L9 are all biconcave lenses. The object side surface of the third lens L3 is convex toward the image side, and the image side surface of the third lens L3 is convex toward the object side. The object side surface of the fourth lens L4 is convex toward the image side, and the image side surface of the fourth lens L4 is convex toward the object side. The object side surface of the ninth lens L9 is convex toward the image side, and the image side surface of the ninth lens L9 is convex toward the object side.

[0053] Optionally, refer to Figure 1 , the second lens L2 is glued with the third lens L3, the fourth lens L4 is glued with the fifth lens L5, and the eighth lens L8 is glued with the ninth lens L9. In the embodiment of the utility model, the second lens L2 is glued with the third lens L3 to correct the chromatic aberration of the first lens group G1. The fourth lens L4 is glued with the fifth lens L5 to correct the chromatic aberration of the second lens group G2. The eighth lens L8 is glued with the ninth lens L9 to correct the chromatic aberration of the third lens group G3. Thus, the chromatic aberration of the medium format high-definition aerial photography lens is corrected as a whole.

[0054] Since most medium-format high-definition aerial photography lenses are shot outdoors, if the light near the 436nm wavelength in the environment is not corrected, purple fringing may occur when shooting outdoor scenes, affecting aerial data collection. In addition to correcting the chromatic aberration of the conventional three wavelengths F, d, and C, it is also necessary to correct the chromatic aberration of the 436nm wavelength. Among them, the F wavelength is 486.13nm blue light, the d wavelength is 587.57nm yellow light, and the C wavelength is 656.28nm red light. To achieve this purpose, the fifth lens L5 and the eighth lens L8 of the utility model embodiment are arranged to use ED dispersion glass, and the sixth lens L6 uses abnormal dispersion glass. Through the reasonable material matching of the fifth lens L5, the sixth lens L6, the eighth lens L8 and other lenses, the chromatic aberration is mutually eliminated at least in the range of 436nm to 656nm. Among them, the ED dispersion glass is an ultra-low dispersion glass.

[0055] Optionally, refer to Figure 1 , the first lens L1, the second lens L2, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 have positive refractive power, and the third lens L3, the fourth lens L4, the ninth lens L9 and the tenth lens L10 have negative refractive power.

[0056] Optionally, refer to Figure 1 , the first lens group G1, the aperture Stop and the second lens group G2 form a double Gaussian structure. The total optical power of the first lens group G1 and the second lens group G2 is Φ12, and the optical power of the third lens group G3 is Φ3, which satisfies: 1.5<Φ12 / Φ3<4. In the embodiment of the utility model, the first lens group G1 and the second lens group G2 form a double Gaussian structure, and the symmetry of the double Gaussian optical structure relative to the aperture Stop is used to effectively correct the off-axis aberration of the medium format high-definition aerial photography lens. In terms of optical power distribution, the total optical power of the first lens group G1 and the second lens group G2 is greater than the optical power of the third lens group G3. The third lens group G3 is used to compensate for the residual aberrations and balance the overall aberrations of the system.

[0057] It should be noted that if Φ12 / Φ3 ≤ 1.5, the third lens group G3 requires more lenses to correct aberrations. Since the third lens group G3 is adjacent to the image plane Image, the outer diameter of the lenses in the third lens group G3 is relatively large. Increasing the number of lenses will increase the overall weight of the medium-format high-definition aerial photography lens and increase the burden on the aerial photography aircraft. If Φ12 / Φ3 ≥ 4, the total optical power allocated to the first lens group G1 and the second lens group G2 increases, and the amount of aberration correction to be borne随之 increases, and the tolerance of the first lens group G1 and the second lens group G2 becomes lower. Since there is a stop Stop between the first lens group G1 and the second lens group G2, in actual assembly, an aperture shutter is placed between the first lens group G1 and the second lens group G2 as the stop Stop of the medium-format high-definition aerial photography lens. The first lens group G1 and the second lens group G2 are assembled from both ends of the aperture shutter. Due to the limitation of processing accuracy, there will be a certain eccentricity in the optical axes of the first lens group G1 and the second lens group G2, reducing the tolerance of the medium-format high-definition aerial photography lens. Therefore, in the embodiment of the present invention, 1.5 < Φ12 / Φ3 < 4 is set, which is beneficial to controlling the tolerance of assembly and reducing the weight of the medium-format high-definition aerial photography lens.

[0058] Optionally, referring to Figure 1 , the distance from the stop Stop to the image plane Image of the medium-format high-definition aerial photography lens is L, and the outer diameter of the image plane Image is D, satisfying: 0.45 < D / L < 0.65. If D / L ≤ 0.45, the optical total length of the medium-format high-definition aerial photography lens is too long, which is not conducive to controlling the volume of the medium-format high-definition aerial photography lens. If D / L ≥ 0.65, to control the CRA of the medium-format high-definition aerial photography lens, the chief ray of the marginal field of view will have a large incident angle or exit angle with the subsequent partial lenses after passing through the stop Stop, increasing the energy loss of the marginal field of view light while increasing the tolerance sensitivity of the medium-format high-definition aerial photography lens, which is not conducive to mass production. Therefore, in the embodiment of the present invention, 0.45 < D / L < 0.65 is set, which can control the volume and tolerance of the medium-format high-definition aerial photography lens while ensuring that the relative illumination of the medium-format high-definition aerial photography lens meets the requirements of the aerial photography lens, facilitating mass production.

[0059] Relative illumination is the ratio of central illumination to peripheral illumination. Relative illumination is an important indicator of aerial lenses. The main factors affecting relative illumination include the vignetting of medium format high-definition aerial lenses in various fields of view, and the matching degree between the CRA of medium format high-definition aerial lenses and the CRA of imaging chips. Among them, the CRA of medium format high-definition aerial lenses refers to the incident angle of the main light of each edge field of view of medium format high-definition aerial lenses on the image plane. The CRA of the imaging chip refers to the angle of each pixel point from the center to the edge on the imaging chip relative to the axial direction. The embodiment of the utility model does not block light for each field of view, so that the vignetting of each field of view is zero, and at the same time controls the difference between the CRA of the medium format high-definition aerial lens and the CRA of the imaging chip under each field of view to be less than ±5°, thereby reducing the energy loss of light in the edge field of view and ensuring that the relative illumination of the medium format high-definition aerial lens meets the requirements of the aerial lens.

[0060] Embodiment 1

[0061] Table 1: Design values ​​of a medium-format high-definition aerial photography lens in Example 1

[0062]

[0063]

[0064] Table 1 shows a design value of a medium-format high-definition aerial camera lens in Example 1. The specific values ​​can be adjusted according to product requirements and are not a limitation to the embodiments of the utility model. The medium-format high-definition aerial camera lens shown in Table 1 can be Figure 2 As shown in . A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the surfaces of each lens. Among them, surface number 1 represents the object side of the first lens 1, surface number 2 represents the image side of the first lens 1, and so on, which will not be repeated here. It should be noted that STO in the surface number column represents the plane where the aperture Stop is located. IMA in the surface number column represents the image surface Image. The radius of curvature represents the degree of curvature of the lens surface. A positive radius of curvature value represents that the center of curvature is on the side of the surface close to the image side, and a negative radius of curvature value represents that the center of curvature is on the side of the surface away from the image side. INF in the radius of curvature column represents that the surface is a plane. The unit of the radius of curvature is mm. The value in the thickness column represents the axial distance from the current surface to the next surface. The unit of thickness is mm. The refractive index column represents the refractive index of the medium between the current surface and the next surface in d light. The space in the refractive index column is the refractive index of air, and the refractive index of air is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light, and the space represents that the current position is air.

[0065] In the first embodiment, the focal length of the medium format high-definition aerial photography lens is 89.94 mm, the F number is 5.59, the field of view angle is 20.4°, the CRA of the medium format high-definition aerial photography lens is 15°, Φ12 / Φ3 is 2.7, and D / L is 0.529.

[0066] Embodiment 2

[0067] The similarities with the first embodiment are not repeated here.

[0068] Table 2: Design values ​​of a medium format high definition aerial photography lens in Example 2

[0069]

[0070]

[0071] Table 2 shows a design value of the medium format high-definition aerial photography lens of Example 2, and its specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the utility model. The medium format high-definition aerial photography lens shown in Table 2 can be Fig. 9 as shown in .

[0072] In the second embodiment, the focal length of the medium format high-definition aerial photography lens is 89.93 mm, the F number is 5.596, the field of view is 20.4°, the CRA of the medium format high-definition aerial photography lens is 14.3°, Φ12 / Φ3 is 1.68, and D / L is 0.544.

[0073] Embodiment 3

[0074] The similarities with the first embodiment are not repeated here.

[0075] Table 3: Design values ​​of a medium format high definition aerial photography lens in Example 3

[0076]

[0077]

[0078] Table 3 shows a design value of the medium-format high-definition aerial photography lens of Example 3, and its specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the utility model. The medium-format high-definition aerial photography lens shown in Table 3 can be Fig.16 as shown in .

[0079] In Example 3, the focal length of the medium format high-definition aerial photography lens is 89.92 mm, the F number is 5.59, the field of view is 20.4°, the CRA of the medium format high-definition aerial photography lens is 14.4°, Φ12 / Φ3 is 2.03, and D / L is 0.523.

[0080] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A medium format high definition aerial photography lens, characterized in that: It comprises a first lens group, an aperture, a second lens group and a third lens group which are arranged in sequence from the object side to the image side along the optical axis; the first lens group, the second lens group and the third lens group each comprise at least two lenses; The first lens group, the second lens group and the third lens group have positive optical power; The first lens group, the aperture and the second lens group form a double Gaussian structure; The total focal power of the first lens group and the second lens group is Φ12, and the focal power of the third lens group is Φ3, satisfying: 1.5<Φ12 / Φ3<4.

2. The medium format high definition aerial photography lens according to claim 1, characterized in that: Composed of 10 lenses; The first lens group includes a first lens, a second lens and a third lens arranged in sequence from the object side to the image side along the optical axis, the second lens group includes a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side along the optical axis, and the third lens group includes a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object side to the image side along the optical axis.

3. The medium format high definition aerial photography lens according to claim 2, characterized in that: The first lens, the sixth lens, the seventh lens and the tenth lens are all meniscus lenses, and are all curved toward the aperture stop.

4. The medium format high definition aerial photography lens according to claim 3, characterized in that: The second lens, the fifth lens and the eighth lens are all biconvex lenses; The third lens, the fourth lens and the ninth lens are all biconcave lenses.

5. The medium format high definition aerial photography lens according to claim 2, characterized in that: The second lens is cemented with the third lens, the fourth lens is cemented with the fifth lens, and the eighth lens is cemented with the ninth lens.

6. The medium format high definition aerial photography lens according to claim 2, characterized in that: The first lens, the second lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens have positive refractive power; The third lens, the fourth lens, the ninth lens and the tenth lens have negative refractive power.

7. The medium format high definition aerial photography lens according to claim 2, characterized in that: The aperture stop is located between the third lens and the fourth lens.

8. The medium format high definition aerial photography lens according to claim 1, characterized in that: The distance from the aperture to the image plane of the medium format high-definition aerial photography lens is L, and the outer diameter of the image plane is D, which satisfies: 0.45 <D / L<0.65。

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