Ultra-wide-angle lens

Abstract

The ultra-wide-angle lens comprises a first lens group, a second lens group, a third lens group and a fourth lens group which are sequentially arranged from an object plane to an image plane along an optical axis, the first lens group comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens; the second lens group comprises a sixth lens; the third lens group comprises a seventh lens; the fourth lens group comprises an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens; the first lens, the second lens, the third lens, the fifth lens, the eighth lens, the eleventh lens, the thirteenth lens and the fifteenth lens have negative focal power, and the fourth lens, the sixth lens, the seventh lens, the ninth lens, the tenth lens, the twelfth lens and the fourteenth lens have positive focal power. And the use requirements of large field angle, low distortion, low chromatic aberration and high image quality are met.

Description

Technical Field

[0001] The utility model relates to the technical field of optical devices, in particular to an ultra-wide-angle lens. Background Art

[0002] Ultra-wide-angle lenses have a wide field of view while effectively correcting distortion. They are used to shoot large scenes such as landscapes, buildings, and the starry sky, and are highly sought after by photography enthusiasts. However, the field of view of today's ultra-wide-angle lenses is generally greater than 110°, and the distortion requirement is less than 3%. This is quite difficult for full-frame lenses, and requires the use of aspherical lenses and a large number of spherical lenses to design. Due to the difficulty of aspherical processing, it is imported from foreign manufacturers for processing, making it more expensive. Therefore, designing a low-cost, cost-effective ultra-wide-angle lens has broad market prospects. Utility Model Content

[0003] The utility model provides an ultra-wide-angle lens which meets the use requirements of large field angle, low distortion, low chromatic aberration and high image quality under the premise of ensuring low cost.

[0004] According to one aspect of the utility model, there is provided an ultra-wide-angle lens, comprising a first lens group, a second lens group, a third lens group and a fourth lens group arranged in sequence from an object plane to an image plane along an optical axis;

[0005] The first lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens;

[0006] The second lens group includes a sixth lens;

[0007] The third lens group includes a seventh lens;

[0008] The fourth lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens;

[0009] The first lens has negative optical power, the second lens has negative optical power, the third lens has negative optical power, the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, the tenth lens has positive optical power, the eleventh lens has negative optical power, the twelfth lens has positive optical power, the thirteenth lens has negative optical power, the fourteenth lens has positive optical power, and the fifteenth lens has negative optical power.

[0010] Optionally, the second lens and the fifteenth lens are glass aspherical lenses, and the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens are glass spherical lenses.

[0011] Optionally, the first lens is a convex-concave lens, the second lens is a convex-concave lens, the third lens is a biconcave lens, the fourth lens is a biconvex lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a biconvex lens, the eighth lens is a convex-concave lens, the ninth lens is a biconvex lens, the tenth lens is a concave-convex lens, the eleventh lens is a concave-convex lens, the twelfth lens is a biconvex lens, the thirteenth lens is a biconcave lens, the fourteenth lens is a biconvex lens, and the fifteenth lens is a concave-convex lens.

[0012] Optionally, the effective aperture of the object side of the second lens is ΦL2S1, and the edge ray lens surface angle is ∠L2S1; the effective aperture of the image side of the second lens is ΦL2S2, and the edge ray lens surface angle is ∠L2S2; the effective aperture of the object side of the fifteenth lens is ΦL15S1, and the edge ray lens surface angle is ∠L15S1; the effective aperture of the image side of the fifteenth lens is ΦL15S2, and the edge ray lens surface angle is ∠L15S2; the thickness ratio of the second lens is δETL2 / δCTL2, and the thickness ratio of the fifteenth lens is δETL15 / δCTL15; wherein,

[0013] ΦL2S1≤38.471;∠L2S1≤41.915;

[0014] ΦL2S2≤29.474;∠L2S2≤56.626;

[0015] ΦL15S1≤23.882;-34.783≤∠L15S1≤-33.580;

[0016] ΦL15S2≤28.897;-2.009≤∠L15S2≤3.987;

[0017] 2.044≤δETL2 / δCTL2≤2.382; 1.944≤δETL15 / δCTL15≤2.460.

[0018] Optionally, the refractive index of the first lens is Nd1, and the Abbe number is Vd1; the refractive index of the second lens is Nd2, and the Abbe number is Vd2; the Abbe number of the sixth lens is Vd6; the Abbe number of the seventh lens is Vd7; the refractive index of the fifteenth lens is Nd15, and the Abbe number is Vd15; wherein:

[0019] 1.75≤Nd1≤1.97; 32.40≤Vd1≤53.10; 1.68≤Nd2≤1.92; 40.00≤Vd2≤43.20; |Vd6-Vd7|≥35; 1.67≤Nd15≤1.85; 36.20≤Vd15≤43.60.

[0020] Optionally, the focal length of the first lens is f1, the focal length of the fifth lens is f5, the focal length of the fifteenth lens is f15, and the focal length of the ultra-wide-angle lens is f, wherein:

[0021] -6.65≤f1 / f≤-4.73; -1.40≤f5 / f≤-1.26; -6.61≤f15 / f≤-5.10.

[0022] Optionally, the optical power of the first lens group is The optical power of the second lens group is The optical power of the third lens group is The optical power of the fourth lens group is in,

[0023] Optionally, a lens diameter of the first lens is ΦL1, and a distance from an optical axis center of the object side surface of the first lens to an image plane is TTL, wherein ΦL1 / TTL≤0.50.

[0024] Optionally, the fourth lens and the fifth lens form a first cemented lens group fA, the eighth lens and the ninth lens form a second cemented lens group fB, the tenth lens and the eleventh lens form a third cemented lens group fC, the focal length of the fifth lens is f5, and the focal length of the tenth lens is f10, wherein:

[0025] -3.22≤fA / f5≤-2.37; -5.86≤fC / f10≤-4.81.

[0026] Optionally, the ultra-wide-angle lens further includes a diaphragm;

[0027] The aperture stop is located in an optical path between the sixth lens and the seventh lens.

[0028] The technical solution of the embodiment of the utility model provides an ultra-wide-angle lens, comprising a first lens group, a second lens group, a third lens group and a fourth lens group arranged in sequence from the object plane to the image plane along the optical axis; the first lens group comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens; the second lens group comprises a sixth lens; the third lens group comprises a seventh lens; the fourth lens group comprises an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens; the first lens has a negative optical power, the second lens has a negative optical power, the third lens has a negative optical power, the fourth lens has a positive optical power, and the fifth lens has a The sixth lens has a positive optical power, the seventh lens has a positive optical power, the eighth lens has a negative optical power, the ninth lens has a positive optical power, the tenth lens has a positive optical power, the eleventh lens has a negative optical power, the twelfth lens has a positive optical power, the thirteenth lens has a negative optical power, the fourteenth lens has a positive optical power, and the fifteenth lens has a negative optical power. The number of lenses in the ultra-wide-angle lens and the relative relationship between the optical powers of each lens are reasonably set to achieve clear imaging, higher image quality and larger aperture under a full-frame camera at a low cost. The image quality of the edge field of view is also significantly improved, meeting the use requirements of a large field of view, low distortion, low chromatic aberration and high image quality.

[0029] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of 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.

[0031] Figure 1 A schematic diagram of the structure of an ultra-wide-angle lens provided by an embodiment of the utility model;

[0032] Figure 2 A schematic diagram of the structure of an ultra-wide-angle lens provided in Embodiment 1 of the present utility model;

[0033] Figure 3 A vertical axis chromatic aberration diagram of an ultra-wide-angle lens provided in Example 1 of the utility model;

[0034] Figure 4 A field curvature distortion diagram of an ultra-wide-angle lens provided in Embodiment 1 of the present utility model;

[0035] Figure 5 This is an MTF diagram of an ultra-wide-angle lens provided in Example 1 of the utility model;

[0036] Figure 6 A schematic diagram of the structure of an ultra-wide-angle lens provided in Embodiment 2 of the present utility model;

[0037] Figure 7 A vertical axis chromatic aberration diagram of an ultra-wide-angle lens provided in Example 2 of the utility model;

[0038] Figure 8 A field curvature distortion diagram of an ultra-wide-angle lens provided in Embodiment 2 of the present utility model;

[0039] Fig. 9 This is an MTF diagram of an ultra-wide-angle lens provided in Example 2 of the present utility model;

[0040] Fig.10 A schematic diagram of the structure of an ultra-wide-angle lens provided in Embodiment 3 of the present utility model;

[0041] Fig.11 A vertical axis chromatic aberration diagram of an ultra-wide-angle lens provided in Embodiment 3 of the present utility model;

[0042] Fig.12 A field curvature distortion diagram of an ultra-wide-angle lens provided in Embodiment 3 of the present utility model;

[0043] Fig.13 This is an MTF diagram of an ultra-wide-angle lens provided in Example 3 of the present utility model. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0045] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0046] Figure 1 A schematic diagram of the structure of an ultra-wide-angle lens provided in an embodiment of the utility model is shown in FIG. Figure 1 As shown, the ultra wide-angle lens includes a first lens group G1, a second lens group G2, a third lens group G3 and a fourth lens group G4 which are arranged in sequence from the object plane to the image plane along the optical axis; the first lens group G1 includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a fifth lens 5; the second lens group G2 includes a sixth lens 6; the third lens group G3 includes a seventh lens 7; the fourth lens group G4 includes an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a twelfth lens 12, a thirteenth lens 13, a fourteenth lens 14 and a fifteenth lens 15 The first lens 1 has negative optical power, the second lens 2 has negative optical power, the third lens 3 has negative optical power, the fourth lens 4 has positive optical power, the fifth lens 5 has negative optical power, the sixth lens 6 has positive optical power, the seventh lens 7 has positive optical power, the eighth lens 8 has negative optical power, the ninth lens 9 has positive optical power, the tenth lens 10 has positive optical power, the eleventh lens 11 has negative optical power, the twelfth lens 12 has positive optical power, the thirteenth lens 13 has negative optical power, the fourteenth lens 14 has positive optical power, and the fifteenth lens 15 has negative optical power.

[0047] Among them, the optical focal length is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the optical focal length, the stronger the ability to bend light, and the smaller the absolute value of the optical focal length, the weaker the ability to bend light. When the optical focal length is a positive number, the refraction of light is convergent; when the optical focal length is a negative number, the refraction of light is divergent. The optical focal length can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group). In the ultra-wide-angle lens provided in this embodiment, each lens can be fixed to a lens barrel ( Figure 1In the optical system (not shown), the first lens 1 has negative focal power, the second lens 2 has negative focal power, which can be used to control the incident angle of the optical system and correct the field curvature; the third lens 3 has negative focal power, the fourth lens 4 has positive focal power, and the fifth lens 5 has negative focal power, so that the first lens group G1 has negative focal power and can quickly collect large-angle light. The second lens group G2 composed of the sixth lens 6 has positive focal power, and the focusing effect can be achieved by moving the second lens group G2, with high image quality at object distances from infinity to close-up. The third lens group G3 composed of the seventh lens 7 has positive focal power, the eighth lens 8 has negative focal power, the ninth lens 9 has positive focal power, the tenth lens 10 has positive focal power, the eleventh lens 11 has negative focal power, the twelfth lens 12 has positive focal power, the thirteenth lens 13 has negative focal power, the fourteenth lens 14 has positive focal power, and the fifteenth lens 15 has negative focal power, so that the fourth lens group G4 has positive focal power, the second lens group G2, the third lens group G3 and the fourth lens group G4 can smooth the light emitted by the first lens group G1, and the focal power of the entire lens is reasonably distributed according to a certain proportion, so as to ensure the balance of the incident angles of the front and rear lenses, reduce the sensitivity of the lens, improve the stability of the lens, and help reduce distortion and improve the possibility of production.

[0048] The ultra-wide-angle lens provided by the embodiment of the utility model ensures the balance of the incident angles of the front and rear lens groups of the ultra-wide-angle lens at a low cost by reasonably setting the number of lenses in the ultra-wide-angle lens and the optical focal length of each lens, reduces the sensitivity of the lens, ensures that the ultra-wide-angle lens has a high resolution, and meets the use requirements of a large field of view, low distortion, low chromatic aberration, and high image quality.

[0049] Optionally, the second lens 2 and the fifteenth lens 15 are glass aspherical lenses, and the first lens 1, 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, the thirteenth lens 13 and the fourteenth lens 14 are glass spherical lenses.

[0050] Among them, in this embodiment, by setting the second lens 2 and the fifteenth lens 15 to be aspherical lenses, off-axis aberrations can be corrected, including field curvature, coma, astigmatism, etc. The first lens 1, 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, the thirteenth lens 13 and the fourteenth lens 14 are all glass spherical lenses, and the optical structure of 13 glass spherical lenses and 2 glass aspherical lenses is used to better correct chromatic aberration and aberration, improve image quality, and reduce processing costs to achieve higher cost performance. The materials of the glass spherical lens and the glass aspherical lens are various types of glass known to those skilled in the art, and the embodiments of the utility model do not repeat them or limit them.

[0051] Optionally, the ultra wide-angle lens further includes a stop STO; the stop STO is located in the light path between the sixth lens 6 and the seventh lens 7.

[0052] Among them, by setting the aperture STO in the optical path between the sixth lens 6 and the seventh lens 7, the propagation direction of the light beam can be adjusted and the incident angle of the light can be adjusted, which is beneficial to improving the imaging quality. At the same time, the aperture is located in the middle of the ultra-wide-angle lens, which can also ensure that the front and rear apertures of the ultra-wide-angle lens are minimized.

[0053] Optionally, the first lens 1 is a convex-concave lens, the second lens 2 is a convex-concave lens, the third lens 3 is a biconcave lens, the fourth lens 4 is a biconvex lens, the fifth lens 5 is a biconcave lens, the sixth lens 6 is a biconvex lens, the seventh lens 7 is a biconvex lens, the eighth lens 8 is a convex-concave lens, the ninth lens 9 is a biconvex lens, the tenth lens 10 is a concave-convex lens, the eleventh lens 11 is a concave-convex lens, the twelfth lens 12 is a biconvex lens, the thirteenth lens 13 is a biconcave lens, the fourteenth lens 14 is a biconvex lens, and the fifteenth lens 15 is a concave-convex lens.

[0054] Among them, the first lens 1 and the second lens 2 are both convex-concave lenses, which can ensure that the wide-angle light is quickly gathered into the optical system, the third lens 3 is a double concave lens, the fourth lens 4 is a double convex lens, the fifth lens 5 is a double concave lens, which can smooth the light, the sixth lens 6 is a double convex lens, and the seventh lens 7 is a double convex lens, which can continue to shrink the light entering the aperture STO to achieve an aperture size of F2.8, the eighth lens 8 is a convex-concave lens, the ninth lens 9 is a double convex lens, the tenth lens 10 is a concave-convex lens, and the eleventh lens 11 is a concave-convex lens, which can better correct the chromatic aberration of the light after passing through the aperture, the twelfth lens 12 is a double convex lens, the thirteenth lens 13 is a double concave lens, and the fourteenth lens 14 is a double convex lens, which can better correct the field curvature under a large field of view, and the fifteenth lens 15 is a concave-convex lens, which can correct off-axis light and improve the image quality of the edge field of view. By reasonably setting the surface shape of each lens, it is ensured that the optical focal length of each lens meets the optical focal length requirements of the above embodiment, and at the same time, the entire ultra-wide-angle lens can be ensured to have a compact structure and a high degree of integration.

[0055] Optionally, the effective aperture of the object side of the second lens 2 is ΦL2S1, and the edge ray lens surface angle is ∠L2S1; the effective aperture of the image side of the second lens 2 is ΦL2S2, and the edge ray lens surface angle is ∠L2S2; the effective aperture of the object side of the fifteenth lens 15 is ΦL15S1, and the edge ray lens surface angle is ∠L15S1; the effective aperture of the image side of the fifteenth lens 15 is ΦL15S2, and the edge ray lens surface angle is ∠L15S2; the thickness ratio of the second lens 2 is δETL2 / δCTL2, and the thickness ratio of the fifteenth lens 15 is δETL2 / δCTL2. The thickness ratio is δETL15 / δCTL15; among which, ΦL2S1≤38.471; ∠L2S1≤41.915; ΦL2S2≤29.474; ∠L2S2≤56.626; ΦL15S1≤23.882; -34.783≤∠L15S1≤-33.580; ΦL15S2≤28.897; -2.009≤∠L15S2≤3.987; 2.044≤δETL2 / δCTL2≤2.382; 1.944≤δETL15 / δCTL15≤2.460.

[0056] Among them, the effective aperture of the second lens 2 and the fifteenth lens 15, the edge ray lens surface angle and the lens thickness ratio are reasonably set, so that the second lens is a convex-concave lens, the surface angles of the object side and the image side are positive, there is no backcurvature, and the aperture size and thickness ratio are moderate; the fifteenth lens is a concave-convex shape, there is no backcurvature on the object side, the backcurvature on the image side is small, and the aperture size and thickness ratio are moderate, and the second lens 2 and the fifteenth lens 15 are both glass aspherical lenses, which can be processed domestically to reduce the lens processing cost.

[0057] Optionally, the refractive index of the first lens 1 is Nd1, and the Abbe number is Vd1; the refractive index of the second lens 2 is Nd2, and the Abbe number is Vd2; the Abbe number of the sixth lens 6 is Vd6; the Abbe number of the seventh lens 7 is Vd7; the refractive index of the fifteenth lens 15 is Nd15, and the Abbe number is Vd15; wherein:

[0058] 1.75≤Nd1≤1.97; 32.40≤Vd1≤53.10; 1.68≤Nd2≤1.92; 40.00≤Vd2≤43.20; |Vd6-Vd7|≥35; 1.67≤Nd15≤1.85; 36.20≤Vd15≤43.60.

[0059] Among them, the refractive index is the ratio of the propagation speed of light in a vacuum to the propagation speed of light in the medium, which is mainly used to describe the refractive ability of a material to light. Different materials have different refractive indices. The Abbe number is an index used to indicate the dispersion ability of a transparent medium. The more serious the dispersion of the medium, the smaller the Abbe number; conversely, the lighter the dispersion of the medium, the larger the Abbe number. The ultra-wide-angle lens in the utility model has a large field of view. The first lens 1 and the second lens 2 use a high refractive index. The range of the medium Abbe number can better ensure that the light is quickly gathered into the optical system, and minimize the spherical aberration and off-axis chromatic aberration caused by the large angle of light refraction; the refractive index and Abbe number setting of the fifteenth lens 15 can meet the image height requirements of the full-frame camera and can be matched with the aspherical design to reduce aberrations and improve the image quality of the edge field of view. The Abbe number setting of the sixth lens 6 and the seventh lens 7 can effectively control the spherical aberration and off-axis chromatic aberration generated by the light after passing through the first lens group G1, and minimize the chromatic aberration when the light angle changes greatly and enters the aperture. In this way, by matching and setting the refractive index and Abbe number of each lens in the ultra-wide-angle lens, it is beneficial to achieve a miniaturized design of the ultra-wide-angle lens; at the same time, it is beneficial to achieve a higher pixel resolution.

[0060] Optionally, the focal length of the first lens 1 is f1, the focal length of the fifth lens 5 is f5, the focal length of the fifteenth lens 15 is f15, and the focal length of the ultra wide-angle lens is f, wherein: -6.65≤f1 / f≤-4.73; -1.40≤f5 / f≤-1.26; -6.61≤f15 / f≤-5.10.

[0061] Furthermore, by reasonably allocating the focal length of each lens, the light can pass through the lens more smoothly, the spherical aberration and field curvature of the lens can be reduced at the same time, and the image quality of the on-axis and off-axis fields of view can be guaranteed. At the same time, it is beneficial to ensure the balance of system tolerance and reduce assembly sensitivity.

[0062] Optionally, the optical power of the first lens group G1 is The optical power of the second lens group G2 is The optical power of the third lens group G3 is The optical power of the fourth lens group G4 is in,

[0063] Among them, the optical focal length of the first lens group G1 accounts for a relatively large proportion and is used to quickly collect light at a large angle. The second lens group G2, the third lens group G3 and the fourth lens group G4 can smooth the light. The optical focal length of the entire ultra-wide-angle lens is distributed according to a certain proportion to ensure the balance of the incident angles of the front and rear lenses, so as to reduce the sensitivity of the lens, improve the stability of the lens, and help reduce distortion.

[0064] Optionally, the lens diameter of the first lens 1 is ΦL1, and the distance from the optical axis center of the object-side surface of the first lens 101 to the image plane is TTL, wherein ΦL1 / TTL≤0.50.

[0065] Among them, the distance from the center of the optical axis of the object side of the first lens 1 to the image plane can be understood as the total optical length of the ultra-wide-angle lens. Reasonable setting of the relationship between the lens diameter of the first lens 1 and the total optical length of the ultra-wide-angle lens can effectively control the overall volume of the lens and prevent the lens from being too large to affect the daily use experience. At the same time, the field of view and the amount of light entering the lens can be increased as much as possible to achieve a wide-angle function. The full field of view angle is ≥121°, which meets the usage requirements under more stringent conditions.

[0066] Optionally, the fourth lens 4 and the fifth lens 5 form a first cemented lens group fA, the eighth lens 8 and the ninth lens 9 form a second cemented lens group fB, the tenth lens 10 and the eleventh lens 11 form a third cemented lens group fC, the focal length of the fifth lens 5 is f5, and the focal length of the tenth lens 10 is f10, wherein: -3.22≤fA / f5≤-2.37; -5.86≤fC / f10≤-4.81.

[0067] Among them, the fourth lens 4 and the fifth lens 5 form a cemented lens group, the eighth lens 8 and the ninth lens 9 form a cemented lens group, and the tenth lens 10 and the eleventh lens 11 form a cemented lens group, which can effectively reduce the air space between the lenses, thereby reducing the total length of the lens. In addition, the cemented lens group can minimize or eliminate chromatic aberration, so that various aberrations of the ultra-wide-angle lens can be fully corrected. Under the premise of compact structure, it can improve resolution, optimize optical properties such as distortion, and reduce light loss caused by reflection between lenses, improve illumination, thereby improving image quality and improving the clarity of lens imaging. In addition, the use of the cemented lens group can also reduce the assembly parts between the two lenses, simplify the assembly procedures in the lens manufacturing process, reduce costs, and reduce the tolerance sensitivity problems such as tilt / eccentricity of the lens unit caused by the assembly process. The ultra-wide-angle lens is conducive to the mutual correction of aberrations such as spherical aberration and coma by reasonably matching the optical power of the two lenses in each cemented lens group, and is also conducive to correcting the chromatic aberration of the lens, thereby obtaining a higher resolution and improving the image quality of the lens.

[0068] The ultra-wide-angle lens provided by the embodiment of the utility model ensures the balance of the incident angles of the front and rear lens groups of the ultra-wide-angle lens at a low cost by reasonably allocating the optical power, surface shape, Abbe number, etc. of each lens, reduces the sensitivity of the lens, improves the stability of the lens, meets the use requirements, and improves the image quality of the lens.

[0069] Specific embodiments of the ultra-wide-angle lens applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings.

[0070] Embodiment 1

[0071] Figure 2 The first embodiment of the present invention provides a schematic diagram of the structure of an ultra-wide-angle lens, as shown in FIG. Figure 2As shown, the ultra-wide-angle lens includes a first lens group G1, a second lens group G2, a third lens group G3 and a fourth lens group G4 which are arranged in sequence from the object plane to the image plane along the optical axis; the first lens group G1 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104 and a fifth lens 105; the second lens group G2 includes a sixth lens 106; the third lens group G3 includes a seventh lens 107; the fourth lens group G4 includes an eighth lens 108, a ninth lens 109, a tenth lens 110, an eleventh lens 111, a twelfth lens 112, a thirteenth lens 113, a fourteenth lens 114 and a fifteenth lens 115; a plane glass CG is also provided along the object plane to the image plane; the plane glass CG is located on the image side of the fifteenth lens 115, and the plane glass CG can protect the photosensitive chip in the imaging sensor to ensure the imaging effect of the ultra-wide-angle lens. The overall layout of the system is that the seven lenses before the aperture STO sequentially constitute the first lens group G1, the second lens group G2 and the third lens group G3, wherein the third lens 103, the fourth lens 104 and the fifth lens 105 are glued together; the eight lenses after the aperture STO constitute the fourth lens group G4, wherein the eighth lens 108 and the ninth lens 109 are glued together and the tenth lens 110 and the eleventh lens 111 are glued together. Exemplarily, Table 1 describes in detail the specific optical and physical parameters of each lens in the ultra-wide-angle lens provided in Example 1 of the utility model in a feasible implementation manner. The ultra-wide-angle lens in Table 1 corresponds to Figure 2 The ultra wide-angle lens.

[0072] Table 1 Design values ​​of optical physical parameters of ultra-wide-angle lens

[0073]

[0074]

[0075] Among them, the surface numbers are numbered according to the surface order of each lens. For example, the surfaces numbered S1 and S2 are the object side and image side of the first lens 101, respectively, and the surfaces numbered S3 and S4 are the object side and image side of the second lens 102, respectively, and so on. The radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side. The thickness represents the central axial distance from the current surface to the next surface. The units of the radius of curvature and thickness are both millimeters (mm). INF represents that the surface is a plane and the radius of curvature is infinite. Material (Nd) represents the refractive index, that is, the ability of the material between the current surface and the next surface to deflect light. A blank space represents that the current position is air and the refractive index is 1. Material (Vd) represents the Abbe number, that is, the dispersion characteristics of the material between the current surface and the next surface to light. A blank space represents that the current position is air. STO represents the aperture.

[0076] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0077]

[0078] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature, that is, the inverse of the radius of curvature; k is the cone coefficient; A~E are the coefficients of the 4th, 6th, 8th, 10th, and 12th order terms of the aspheric polynomial.

[0079] Exemplarily, Table 2 describes in detail the aspheric coefficients of each lens in the first embodiment in a feasible implementation manner.

[0080] Table 2 Aspheric coefficients of each lens in the ultra-wide-angle lens

[0081]

[0082] Among them, -6.6972155346E-05 means that the coefficient A of the surface number S1 is 6.6972155346*10 -5 , and so on.

[0083] Figure 3 This is a vertical axis chromatic aberration diagram of an ultra-wide-angle lens provided in Example 1 of the utility model, such as Figure 3 As shown in the figure, the vertical direction is the field of view, 0 means on the optical axis, and the vertical vertex represents the maximum half field of view; the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). If the vertical axis chromatic aberration is too large, it will cause the object image to disperse and affect the image clarity. Figure 3 It can be seen that the vertical axis chromatic aberration of different wavelengths is controlled within a reasonable range and is relatively close to the main light. The 0.8 field of view wavelength can be controlled within 6um, which significantly improves the common purple fringing phenomenon.

[0084] Figure 4 This is a field curvature distortion diagram of an ultra-wide-angle lens provided in Embodiment 1 of the present utility model, such as Figure 4 As shown in the figure, in the coordinate system on the right side, the horizontal coordinate represents the size of the distortion, the unit is %; the vertical coordinate represents the normalized image height, no unit; Figure 4 It can be seen that the distortion of the lens provided in this embodiment is well corrected, which better ensures the authenticity of the object imaging and has small imaging distortion. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, without units; T represents the meridian, S represents the sagittal; Figure 4 It can be seen that the resolution difference between the center of the field curvature of the lens provided in this embodiment and that near the edge of the field of view is relatively small.

[0085] Figure 5This is an MTF diagram of an ultra-wide-angle lens provided in Example 1 of the present invention. The horizontal axis is the spatial frequency, which refers to the number of black and white line pairs / 1mm. The vertical axis is the modulation modulus (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging, so 0≤M' / M≤1. The MTF curve shows the resolution of the optical system for objects at different frequencies in different fields of view, meridian and sagittal directions, and reflects the degree of imaging of the image quality of the object after passing through the optical system. The higher the MTF, the higher the imaging quality of the lens. Figure 5 It can be seen that the MTF of the optical system in all meridian and sagittal directions of the field of view is greater than 0.4 when the spatial frequency is 40lp / mm, which has a very high imaging effect for SLR cameras.

[0086] Embodiment 2

[0087] Figure 6 This is a schematic diagram of the structure of an ultra-wide-angle lens provided in Embodiment 2 of the present utility model, as shown in FIG. Figure 6 As shown, the ultra-wide-angle lens includes a first lens group G1, a second lens group G2, a third lens group G3 and a fourth lens group G4 which are arranged in sequence from the object plane to the image plane along the optical axis; the first lens group G1 includes a first lens 201, a second lens 202, a third lens 203, a fourth lens 204 and a fifth lens 205; the second lens group G2 includes a sixth lens 206; the third lens group G3 includes a seventh lens 207; the fourth lens group G4 includes an eighth lens 208, a ninth lens 209, a tenth lens 210, an eleventh lens 211, a twelfth lens 212, a thirteenth lens 213, a fourteenth lens 214 and a fifteenth lens 215; a plane glass CG is also provided along the object plane to the image plane; the plane glass CG is located on the image side of the fifteenth lens 215, and the plane glass CG can protect the photosensitive chip in the imaging sensor to ensure the imaging effect of the ultra-wide-angle lens. The overall layout of the system is that the seven lenses before the aperture STO constitute the first lens group G1, the second lens group G2 and the third lens group G3 in sequence, wherein the fourth lens 204 and the fifth lens 205 are glued together; the eight lenses after the aperture STO constitute the fourth lens group G4, wherein the eighth lens 208 and the ninth lens 209 are glued together, and the tenth lens 210 and the eleventh lens 211 are glued together.

[0088] For example, Table 3 describes in detail the specific optical and physical parameters of each lens in the ultra-wide-angle lens provided in Example 2 of the present utility model in a feasible implementation manner. The ultra-wide-angle lens in Table 3 corresponds to Figure 6 The ultra wide-angle lens.

[0089] Table 3 Design values ​​of optical physical parameters of ultra-wide-angle lens

[0090]

[0091]

[0092] Among them, the surface numbers are numbered according to the surface order of each lens. For example, the surfaces numbered S1 and S2 are the object side and image side of the first lens 201, respectively, and the surfaces numbered S3 and S4 are the object side and image side of the second lens 202, respectively, and so on. The radius of curvature represents the curvature of the lens surface. A positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side. The thickness represents the central axial distance from the current surface to the next surface. The units of the radius of curvature and thickness are both millimeters (mm). INF represents that the surface is a plane and the radius of curvature is infinite. Material (Nd) represents the refractive index, that is, the ability of the material between the current surface and the next surface to deflect light. A blank space represents that the current position is air and the refractive index is 1. Material (Vd) represents the Abbe number, that is, the dispersion characteristics of the material between the current surface and the next surface to light. A blank space represents that the current position is air. STO represents the aperture.

[0093] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0094]

[0095] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature, that is, the inverse of the radius of curvature; k is the cone coefficient; A~E are the coefficients of the 4th, 6th, 8th, 10th, and 12th order terms of the aspheric polynomial.

[0096] Exemplarily, Table 4 describes in detail the aspheric coefficients of each lens in the second embodiment in a feasible implementation manner.

[0097] Table 4 Aspheric coefficients of each lens in the ultra-wide-angle lens

[0098]

[0099] Among them, -6.6972155346E-05 means that the coefficient A of the surface number S1 is 6.6972155346*10 -5 , and so on.

[0100] Figure 7 The vertical axis chromatic aberration diagram of an ultra-wide-angle lens provided in the second embodiment of the utility model is as follows: Figure 7 As shown in the figure, the vertical direction is the field of view, 0 means on the optical axis, and the vertical vertex represents the maximum half field of view; the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). If the vertical axis chromatic aberration is too large, it will cause the object image to disperse and affect the image clarity. Figure 7It can be seen that the vertical axis chromatic aberration of different wavelengths is controlled within a reasonable range and is relatively close to the main light. The 0.8 field of view wavelength can be controlled within 6um, which significantly improves the common purple fringing phenomenon.

[0101] Figure 8 This is a field curvature distortion diagram of an ultra-wide-angle lens provided in Embodiment 2 of the present utility model, such as Figure 8 As shown in the figure, in the coordinate system on the right side, the horizontal coordinate represents the size of the distortion, the unit is %; the vertical coordinate represents the normalized image height, no unit; Figure 8 It can be seen that the distortion of the lens provided in this embodiment is well corrected, which better ensures the authenticity of the object imaging and has small imaging distortion. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, without units; T represents the meridian, S represents the sagittal; Figure 8 It can be seen that the resolution difference between the center of the field curvature of the lens provided in this embodiment and that near the edge of the field of view is relatively small.

[0102] Fig. 9 This is an MTF diagram of an ultra-wide-angle lens provided in Example 2 of the present utility model. The horizontal axis is the spatial frequency, which refers to the number of black and white line pairs / 1mm. The vertical axis is the modulation modulus (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging, so 0≤M' / M≤1. The MTF curve shows the resolution of the optical system for objects at different frequencies in different fields of view, meridian and sagittal directions, and reflects the degree of imaging of the image quality of the object after passing through the optical system. The higher the MTF, the higher the imaging quality of the lens. Fig. 9 It can be seen that the MTF of the optical system in all meridian and sagittal directions of the field of view is greater than 0.4 when the spatial frequency is 40lp / mm, which has a very high imaging effect for SLR cameras.

[0103] Embodiment 3

[0104] Fig.10 This is a schematic diagram of the structure of an ultra-wide-angle lens provided in Embodiment 3 of the present utility model, as shown in FIG. Fig.10As shown, the ultra-wide-angle lens includes a first lens group G1, a second lens group G2, a third lens group G3 and a fourth lens group G4 which are arranged in sequence from the object plane to the image plane along the optical axis; the first lens group G1 includes a first lens 301, a second lens 302, a third lens 303, a fourth lens 304 and a fifth lens 305; the second lens group G2 includes a sixth lens 306; the third lens group G3 includes a seventh lens 307; the fourth lens group G4 includes an eighth lens 308, a ninth lens 309, a tenth lens 310, an eleventh lens 311, a twelfth lens 312, a thirteenth lens 313, a fourteenth lens 314 and a fifteenth lens 315; a plane glass CG is also provided along the object plane to the image plane; the plane glass CG is located on the image side of the fifteenth lens 315, and the plane glass CG can protect the photosensitive chip in the imaging sensor to ensure the imaging effect of the ultra-wide-angle lens. The overall layout of the system is that the seven lenses before the aperture STO sequentially constitute the first lens group G1, the second lens group G2 and the third lens group G3, in which the fourth lens 304 and the fifth lens 305 are glued together; the eight lenses after the aperture STO constitute the fourth lens group G4, in which the eighth lens 308 and the ninth lens 309 are glued together, and the tenth lens 310 and the eleventh lens 311 are glued together. Exemplarily, Table 5 describes in detail the specific optical and physical parameters of each lens in the ultra-wide-angle lens provided in Example 3 of the utility model in a feasible implementation manner. The ultra-wide-angle lens in Table 5 corresponds to Fig.10 The ultra wide-angle lens.

[0105] Table 5 Design values ​​of optical physical parameters of ultra-wide-angle lens

[0106]

[0107]

[0108] Among them, the surface numbers are numbered according to the surface order of each lens. For example, the surfaces numbered S1 and S2 are the object side and image side of the first lens 301, respectively, and the surfaces numbered S3 and S4 are the object side and image side of the second lens 302, respectively, and so on. The radius of curvature represents the curvature of the lens surface. A positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side. The thickness represents the central axial distance from the current surface to the next surface. The units of the radius of curvature and thickness are both millimeters (mm). INF represents that the surface is a plane and the radius of curvature is infinite. Material (Nd) represents the refractive index, that is, the ability of the material between the current surface and the next surface to deflect light. A blank space represents that the current position is air and the refractive index is 1. Material (Vd) represents the Abbe number, that is, the dispersion characteristics of the material between the current surface and the next surface to light. A blank space represents that the current position is air. STO represents the aperture.

[0109] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0110]

[0111] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature, that is, the inverse of the radius of curvature; k is the cone coefficient; A~E are the coefficients of the 4th, 6th, 8th, 10th, and 12th order terms of the aspheric polynomial.

[0112] Exemplarily, Table 6 describes in detail the aspheric coefficients of each lens in the third embodiment in a feasible implementation manner.

[0113] Table 6 Aspheric coefficients of each lens in the ultra-wide-angle lens

[0114]

[0115]

[0116] Among them, -6.6972155346E-05 means that the coefficient A of the surface number S1 is 6.6972155346*10 -5 , and so on.

[0117] Fig.11 This is a vertical axis chromatic aberration diagram of an ultra-wide-angle lens provided in Embodiment 3 of the present utility model, such as Fig.11 As shown in the figure, the vertical direction is the field of view, 0 means on the optical axis, and the vertical vertex represents the maximum half field of view; the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). If the vertical axis chromatic aberration is too large, it will cause the object image to disperse and affect the image clarity. Fig.11 It can be seen that the vertical axis chromatic aberration of different wavelengths is controlled within a reasonable range and is relatively close to the main light. The 0.8 field of view wavelength can be controlled within 6um, which significantly improves the common purple fringing phenomenon.

[0118] Fig.12 This is a field curvature distortion diagram of an ultra-wide-angle lens provided in Embodiment 3 of the present utility model, such as Fig.12 As shown in the figure, in the coordinate system on the right side, the horizontal coordinate represents the size of the distortion, the unit is %; the vertical coordinate represents the normalized image height, no unit; Fig.12 It can be seen that the distortion of the lens provided in this embodiment is well corrected, which better ensures the authenticity of the object imaging and has small imaging distortion. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, without units; T represents the meridian, S represents the sagittal; Fig.12 It can be seen that the resolution difference between the center of the field curvature of the lens provided in this embodiment and that near the edge of the field of view is relatively small.

[0119] Fig.13 This is an MTF diagram of an ultra-wide-angle lens provided in Example 3 of the present utility model. The horizontal axis is the spatial frequency, which refers to the number of black and white line pairs / 1mm. The vertical axis is the modulation modulus (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging, so 0≤M' / M≤1. The MTF curve shows the resolution of the optical system for objects at different frequencies in different fields of view, meridian and sagittal directions, and reflects the degree of imaging of the image quality of the object after passing through the optical system. The higher the MTF, the higher the imaging quality of the lens. Fig.13 It can be seen that the MTF of the optical system in all meridian and sagittal directions of the field of view is greater than 0.4 when the spatial frequency is 40lp / mm, which has a very high imaging effect for SLR cameras.

[0120] In summary, the ultra-wide-angle lens provided by the embodiment of the utility model realizes an ultra-wide-angle lens with low cost, high cost performance, low distortion and no obvious purple fringing. The design adopts an optical structure of 13 glass spherical lenses and 2 glass aspherical lenses, which realizes clear imaging, higher image quality and larger aperture under a full-frame camera. The image quality of the edge field of view is also significantly improved, which is suitable for use in more situations. Through the combination of multiple glued structures, the vertical axis chromatic aberration of the full field of view of each wavelength is ≤0.006mm, and when the full field of view angle is ≥121°, the |optical distortion| is ≤1.2%, and the purple fringing phenomenon is improved. The processing performance of the aspherical surface also meets the requirements of domestic manufacturers for mass production, that is, it can achieve low distortion, low chromatic aberration, and high image quality performance, and can also reduce processing costs and achieve higher cost performance.

[0121] In order to more clearly illustrate the above embodiments, Table 7 details the specific optical and physical parameters of each lens in the ultra-wide-angle lens provided in Embodiments 1 to 3 of the present invention and other feasible optical and physical parameters.

[0122] Table 7 Design values ​​of optical physical parameters of ultra-wide-angle lens

[0123]

[0124] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. An ultra-wide-angle lens, characterized in that: comprising a first lens group, a second lens group, a third lens group and a fourth lens group arranged in sequence from the object plane to the image plane along the optical axis; The first lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens; The second lens group includes a sixth lens; The third lens group includes a seventh lens; The fourth lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens; The first lens has negative optical power, the second lens has negative optical power, the third lens has negative optical power, the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, the tenth lens has positive optical power, the eleventh lens has negative optical power, the twelfth lens has positive optical power, the thirteenth lens has negative optical power, the fourteenth lens has positive optical power, and the fifteenth lens has negative optical power.

2. The ultra-wide-angle lens according to claim 1, characterized in that: The second lens and the fifteenth lens are glass aspherical lenses, and the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens are glass spherical lenses.

3. The ultra-wide-angle lens according to claim 1, characterized in that: The first lens is a convex-concave lens, the second lens is a convex-concave lens, the third lens is a biconcave lens, the fourth lens is a biconvex lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a biconvex lens, the eighth lens is a convex-concave lens, the ninth lens is a biconvex lens, the tenth lens is a concave-convex lens, the eleventh lens is a concave-convex lens, the twelfth lens is a biconvex lens, the thirteenth lens is a biconcave lens, the fourteenth lens is a biconvex lens, and the fifteenth lens is a concave-convex lens.

4. The ultra-wide-angle lens according to claim 1, characterized in that: The effective aperture of the object side of the second lens is ΦL2S1, and the edge ray lens surface angle is ∠L2S1; the effective aperture of the image side of the second lens is ΦL2S2, and the edge ray lens surface angle is ∠L2S2; the effective aperture of the object side of the fifteenth lens is ΦL15S1, and the edge ray lens surface angle is ∠L15S1; the effective aperture of the image side of the fifteenth lens is ΦL15S2, and the edge ray lens surface angle is ∠L15S2; the thickness ratio of the second lens is δETL2 / δCTL2, and the thickness ratio of the fifteenth lens is δETL15 / δCTL15; wherein, ΦL2S1≤38.471;∠L2S1≤41.915; ΦL2S2≤29.474;∠L2S2≤56.626; ΦL15S1≤23.882;-34.783≤∠L15S1≤-33.580; ΦL15S2≤28.897;-2.009≤∠L15S2≤3.987; 2.044≤δETL2 / δCTL2≤2.382; 1.944≤δETL15 / δCTL15≤2.

460.

5. The ultra-wide-angle lens according to claim 1, characterized in that: The refractive index of the first lens is Nd1, and the Abbe number is Vd1; the refractive index of the second lens is Nd2, and the Abbe number is Vd2; the Abbe number of the sixth lens is Vd6; the Abbe number of the seventh lens is Vd7; the refractive index of the fifteenth lens is Nd15, and the Abbe number is Vd15; wherein: 1.75≤Nd1≤1.97; 32.40≤Vd1≤53.10; 1.68≤Nd2≤1.92; 40.00≤Vd2≤43.20; |Vd6-Vd7|≥35; 1.67≤Nd15≤1.85; 36.20≤Vd15≤43.

60.

6. The ultra-wide-angle lens according to claim 1, characterized in that: The focal length of the first lens is f1, the focal length of the fifth lens is f5, the focal length of the fifteenth lens is f15, and the focal length of the ultra-wide-angle lens is f, wherein: -6.65≤f1 / f≤-4.73; -1.40≤f5 / f≤-1.26; -6.61≤f15 / f≤-5.

10.

7. The ultra-wide-angle lens according to claim 1, characterized in that: The optical focal power of the first lens group is φ1, the optical focal power of the second lens group is φ2, the optical focal power of the third lens group is φ3, and the optical focal power of the fourth lens group is φ4, wherein -0.86<(φ2+φ3+φ4) / φ1<-0.

74.

8. The ultra-wide-angle lens according to claim 1, characterized in that: The lens diameter of the first lens is ΦL1, and the distance from the optical axis center of the object side surface of the first lens to the image plane is TTL, wherein ΦL1 / TTL≤0.

50.

9. The ultra-wide-angle lens according to claim 1, characterized in that: The fourth lens and the fifth lens form a first cemented lens group fA, the eighth lens and the ninth lens form a second cemented lens group fB, the tenth lens and the eleventh lens form a third cemented lens group fC, the focal length of the fifth lens is f5, and the focal length of the tenth lens is f10, wherein: -3.22≤fA / f5≤-2.37; -5.86≤fC / f10≤-4.

81.

10. The ultra-wide-angle lens according to claim 1, characterized in that: The ultra-wide-angle lens further includes an aperture; The aperture stop is located in an optical path between the sixth lens and the seventh lens.

Images