A large aperture wide-angle lens

Abstract

The present invention discloses a large aperture wide-angle lens, comprising: a first lens group, a second lens group, an aperture, and a third lens group, arranged in sequence from the object side to the image side; the first lens group comprises: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, arranged in sequence along the optical axis, wherein the first lens is a positive lens curved toward the aperture, and the second and third lenses are negative lenses; the second lens group comprises: a sixth lens and a seventh lens, arranged in sequence along the optical axis, both of which are positive lenses; and the third 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, arranged in sequence along the optical axis. A large aperture wide-angle structure constructed using three groups is achieved by rationally matching and combining the optical power, material, and shape of each optical lens, thereby achieving good imaging across the entire field of view at a fully open aperture of F1.8.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a large aperture wide-angle lens. Background Art

[0002] Wide-angle lenses have a relatively short focal length, a wide field of view, and a relatively deep depth of field. When photographing large scenes, they can effectively convey the expansive grandeur of the scene, often used for subjects like architecture and landscapes. However, currently popular wide-angle lenses often have an F-number greater than 2.4, which hinders overall color quality and is also expensive. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a large aperture wide-angle lens that effectively solves the problems of poor image quality and high price.

[0004] A large aperture wide-angle lens according to an embodiment of the present invention includes: a first lens group, a second lens group, a stop, and a third lens group, which are sequentially arranged from the object side to the image side;

[0005] The first lens group includes: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence along the optical axis, the first lens is a positive lens curved toward the aperture stop, the second lens and the third lens are negative lenses, the fourth lens is a positive lens, and the fifth lens is a negative lens;

[0006] The second lens group includes a sixth lens and a seventh lens arranged in sequence along the optical axis, and both the sixth lens and the seventh lens are positive lenses;

[0007] The third 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, which are arranged in sequence along the optical axis. The eighth lens, the tenth lens, the eleventh lens, the twelfth lens, and the fifteenth lens are positive lenses, and the ninth lens, the thirteenth lens, and the fourteenth lens are negative lenses.

[0008] A large aperture wide-angle lens according to an embodiment of the present invention has at least the following beneficial effects:

[0009] It adopts a large aperture wide-angle structure constructed of three groups, and rationally matches and combines the optical power, material, and shape of each optical lens, so that good imaging is achieved within the entire field of view at the full aperture of F1.8.

[0010] According to some embodiments of the present invention, the first lens is a meniscus lens with its convex surface facing the object plane; the second lens is a meniscus lens with its convex surface facing the object plane; the third lens is a meniscus lens with its convex surface facing the object plane; 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 meniscus lens with its convex surface facing the object plane; the eighth lens is a biconvex lens; the ninth lens is a biconcave lens; the tenth lens is a biconvex lens; the eleventh lens is a biconvex lens; the twelfth lens is a biconvex lens; the thirteenth lens is a meniscus lens with its convex surface facing the image plane; the fourteenth lens is a meniscus lens with its convex surface facing the object plane; and the fifteenth lens is a meniscus lens with its convex surface facing the object plane.

[0011] According to some embodiments of the present invention, the ninth lens and the tenth lens are combined into a cemented lens.

[0012] According to some embodiments of the present invention, the twelfth lens and the thirteenth lens are combined into a cemented lens.

[0013] According to some embodiments of the present invention, the large aperture wide-angle lens satisfies the following relationship:

[0014] F1 / F=7.04, F1=140.83;

[0015] F2 / F=-1.57, F2=-31.51;

[0016] F3 / F=-2.22, F3=-44.58;

[0017] F4 / F=2.13,F4=42.68;

[0018] F5 / F=-1.88, F5=-37.67;

[0019] F6 / F=1.61,F6=32.1;

[0020] F7 / F=18.15,F7=363.10;

[0021] F8 / F=4.13, F8=82.76;

[0022] F 9-10 / F=-1.69,F 9-10 =-33.98;

[0023] F 11 / F=2.14,F 11 =42.98;

[0024] F 12-13 / F=3.91,F 12-13=78.39;

[0025] F 14 / F=-6.1,F 14 =-122.21;

[0026] F 15 / F=10.21,F 15 =204.25;

[0027] F G1 / F=-0.9,F G1 =-18.53;

[0028] F G2 / F=1.66,F G2 =28.01;

[0029] F G3 / F=2.24,F G3 =44.82;

[0030] Where F is the effective focal length of the lens, F1 is the focal length of the first lens, F2 is the focal length of the second lens, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, F5 is the focal length of the fifth lens, F6 is the focal length of the sixth lens, F7 is the focal length of the seventh lens, F8 is the focal length of the eighth lens, and F 9-10 is the combined focal length of the cemented lens composed of the ninth lens and the tenth lens, F 11 is the focal length of the tenth lens, F 12-13 is the combined focal length of the cemented lens composed of the twelfth lens and the thirteenth lens, F 14 is the focal length of the fourteenth lens, F 15 is the focal length of the fifteenth lens, F G1 is the combined focal length of the first lens group, F G2 is the combined focal length of the second lens group, F G3 is the combined focal length of the third lens group.

[0031] According to some embodiments of the present invention, the focal length F of the large aperture wide-angle lens and the total optical length L of the large aperture wide-angle lens satisfy the relationship: 5.5≤F / L≤8.5.

[0032] According to some embodiments of the present invention, the tenth lens element is made of a low-dispersion ED material, and the difference in Abbe number between the tenth lens element and the ninth lens element is greater than or equal to 40.

[0033] According to some embodiments of the present invention, the first lens group, the second lens group, and the third lens group all use glass lenses.

[0034] According to some embodiments of the present invention, a filter group and / or protective glass is provided between the fifteenth lens and the image side.

[0035] According to some embodiments of the present invention, the large aperture wide-angle lens has a focal length F=20 mm, an aperture value FNO=1.8, and a field of view angle of 94.94°.

[0036] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0038] Figure 1 Schematic diagram of the optical system structure of an embodiment of the present invention when the object distance is infinite;

[0039] Figure 2 is a rayfan diagram of an embodiment of the present invention when the object distance is infinite;

[0040] Figure 3 This is a vertical axial chromatic aberration image of an embodiment of the present invention when the object distance is infinite.

[0041] Figure Number:

[0042] First lens group G1, second lens group G2, aperture stop STO, third lens group G3, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, ninth lens L9, tenth lens L10, eleventh lens L11, twelfth lens L12, thirteenth lens L13, fourteenth lens L14, fifteenth lens L15. DETAILED DESCRIPTION

[0043] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0044] In the description of the present invention, it should be understood that descriptions involving orientation, such as the orientation or positional relationship indicated by up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] In the description of the present invention, "a plurality" refers to more than two. The use of "first" or "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of the indicated technical features, or implicitly indicating the order of the indicated technical features.

[0046] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0047] Reference Figure 1 FIG. 1 shows a large aperture wide-angle lens according to an embodiment of the present invention, comprising: a first lens group G1; a second lens group G2; an aperture stop STO; and a third lens group G3, spaced in order from the object side to the image side. The lens is divided into three groups. The combined focal power of the first lens group G1 in the front group is negative, while the combined focal power of the second lens group G2 and the third lens group G3 in the rear group is positive. The combination forms a typical "reverse telephoto" optical structure, which is beneficial for increasing the optical back focus, thereby making the lens suitable for different camera mounts.

[0048] Among them, the first lens group G1 includes: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 arranged in sequence along the optical axis. The first lens L1 is a positive lens curved toward the aperture STO, the second lens L2 and the third lens L3 are negative lenses, the fourth lens L4 is a positive lens, and the fifth lens L5 is a negative lens. The first lens of this lens is a positive lens curved toward the aperture, and its refractive index and relative dispersion coefficient are very different from those of the subsequent second lens L2 and third lens L3, which can correct spherical aberration, chromatic aberration, and distortion. The second lens L2 and the third lens L3 can continuously reduce the field of view angle, reducing the pressure on correcting off-axis aberrations of the rear lens group.

[0049] The second lens group G2 includes a sixth lens L6 and a seventh lens L7 arranged in sequence along the optical axis. Both the sixth lens L6 and the seventh lens L7 are positive lenses. Since the relative aperture of the on-axis light increases after being strongly diverged by the front lens group, the second lens group G2 uses two positive lenses in succession to correct the increased spherical aberration.

[0050] The third lens group G3 includes: an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, a thirteenth lens L13, a fourteenth lens L14, and a fifteenth lens L15, which are arranged in sequence along the optical axis. The eighth lens L8, the tenth lens L10, the eleventh lens L11, the twelfth lens L12, and the fifteenth lens L15 are positive lenses, and the ninth lens L9, the thirteenth lens L13, and the fourteenth lens L14 are negative lenses.

[0051] This technical solution adopts a large aperture wide-angle structure constructed of three groups, and reasonably matches and combines the optical power, material, and shape of each optical lens, so that good imaging can be achieved within the entire field of view when the full aperture is F1.8.

[0052] like Figure 1 As shown, in some embodiments of the present invention, the first lens L1 is a meniscus lens with its convex surface facing the object plane; the second lens L2 is a meniscus lens with its convex surface facing the object plane; the third lens L3 is a meniscus lens with its convex surface facing the object plane; the fourth lens L4 is a biconvex lens; the fifth lens L5 is a biconcave lens; the sixth lens L6 is a biconvex lens; the seventh lens L7 is a meniscus lens with its convex surface facing the object plane; the eighth lens L8 is a biconvex lens; the ninth lens L9 is a biconcave lens; the tenth lens L10 is a biconvex lens; the eleventh lens L11 is a biconvex lens; the twelfth lens L12 is a biconvex lens; the thirteenth lens L13 is a meniscus lens with its convex surface facing the image plane; the fourteenth lens L14 is a meniscus lens with its convex surface facing the object plane; and the fifteenth lens L15 is a meniscus lens with its convex surface facing the object plane.

[0053] In some embodiments of the present invention, the ninth lens L9 and the tenth lens L10 are combined into a cemented lens, which can control high-order spherical aberration and chromatic aberration.

[0054] In some embodiments of the present invention, the twelfth lens L12 and the thirteenth lens L13 are combined into a cemented lens, which can control high-order spherical aberration and chromatic aberration in the rear lens group.

[0055] Furthermore, in some embodiments of the present invention, the large aperture wide-angle lens satisfies the following relationship:

[0056] F1 / F=7.04, F1=140.83;

[0057] F2 / F=-1.57, F2=-31.51;

[0058] F3 / F=-2.22, F3=-44.58;

[0059] F4 / F=2.13,F4=42.68;

[0060] F5 / F=-1.88, F5=-37.67;

[0061] F6 / F=1.61,F6=32.1;

[0062] F7 / F=18.15,F7=363.10;

[0063] F8 / F=4.13, F8=82.76;

[0064] F 9-10 / F=-1.69,F 9-10 =-33.98;

[0065] F 11 / F=2.14,F 11 =42.98;

[0066] F 12-13 / F=3.91,F 12-13 =78.39;

[0067] F 14 / F=-6.1,F 14 =-122.21;

[0068] F 15 / F=10.21,F 15 =204.25;

[0069] F G1 / F=-0.9,F G1 =-18.53;

[0070] F G2 / F=1.66,F G2 =28.01;

[0071] F G3 / F=2.24,F G3 =44.82;

[0072] Where F is the effective focal length of the lens, F1 is the focal length of the first lens L1, F2 is the focal length of the second lens L2, F3 is the focal length of the third lens L3, F4 is the focal length of the fourth lens L4, F5 is the focal length of the fifth lens L5, F6 is the focal length of the sixth lens L6, F7 is the focal length of the seventh lens L7, F8 is the focal length of the eighth lens L8, and F 9-10 is the combined focal length of the cemented lens composed of the ninth lens L9 and the tenth lens L10, F 11 is the focal length of the tenth lens L11, F 12-13 is the combined focal length of the cemented lens composed of the twelfth lens L12 and the thirteenth lens L13, F 14 is the focal length of the fourteenth lens L14, F 15 is the focal length of the fifteenth lens L15, F G1 is the combined focal length of the first lens group G1, F G2 is the combined focal length of the second lens group G2, F G3 is the combined focal length of the third lens group G3.

[0073] In some embodiments of the present invention, the focal length F of the large aperture wide-angle lens and the total optical length L of the large aperture wide-angle lens satisfy the relationship: 5.5≤F / L≤8.5. Specifically, in embodiments of the present invention, the lens optical system satisfies the following relationship:

[0074] FOV=94.94°, F.NO=1.8, EFL=20mm, TTL=155.9mm;

[0075] Where FOV is the field of view of the lens, F.NO is the relative aperture of the lens, EFL is the effective focal length of the lens, and TTL is the total optical length of the lens (the length from the vertex of the first single lens to the imaging surface).

[0076] In some embodiments of the present invention, the tenth lens L10 is made of a low-dispersion ED material, and the difference in Abbe number between the tenth lens L10 and the ninth lens L9 is greater than or equal to 40, which is very useful for eliminating chromatic aberration.

[0077] In some embodiments of the present invention, the first lens group G1 , the second lens group G2 , and the third lens group G3 are all made of glass lenses. This all-glass combination has excellent temperature stability.

[0078] In addition, in some embodiments of the present invention, a filter group and / or protective glass is provided between the fifteenth lens L15 and the image side. The filter can attenuate a portion of long-wave and stray light, preventing the photosensitive chip from being interfered with by infrared rays, thereby making the image quality clear and the colors bright; the protective glass can protect the chip from direct damage by external forces.

[0079] In some embodiments of the present invention, by minimizing or eliminating vignetting, the lens allows as much peripheral field light as possible to pass through the lens and reach the chip surface, thereby achieving a high relative illumination and ensuring overall uniformity and transparency of image plane brightness. In some embodiments of the present invention, the large aperture wide-angle lens has a focal length of f = 20mm, an FNO = 1.8, and a field of view of 94.94°.

[0080] The following specific embodiments of this solution are used to illustrate the large aperture wide-angle lens. Parameters of various embodiments that meet the above conditions are shown in the following table: The units of radius R and thickness are both millimeters.

[0081]

[0082]

[0083] Table 1

[0084] like Figure 2As shown in FIG, it is a rayfan diagram of an embodiment of the present invention when the object distance is infinite. It can be seen that in all fields of view, all kinds of aberrations are corrected within a relatively ideal range. Figure 3 As shown, the vertical axis chromatic aberration image of the embodiment of the present invention when the object distance is infinite can be seen that the vertical axis chromatic aberration of the long wave and the short wave is controlled within the range of 12 microns, and no obvious purple fringing phenomenon occurs.

[0085] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A large aperture wide-angle lens, comprising 15 lenses, characterized in that: The lens comprises: a first lens group (G1), a second lens group (G2), a stop (STO), and a third lens group (G3) arranged in sequence from the object side to the image side; The first lens group (G1) includes: a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), and a fifth lens (L5) arranged in sequence along the optical axis, the first lens (L1) being a positive lens bent toward the aperture (STO), the second lens (L2) and the third lens (L3) being negative lenses, the fourth lens (L4) being a positive lens, and the fifth lens (L5) being a negative lens; The second lens group (G2) comprises a sixth lens (L6) and a seventh lens (L7) arranged in sequence along the optical axis, and both the sixth lens (L6) and the seventh lens (L7) are positive lenses; The third lens group (G3) includes: an eighth lens (L8), a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), a twelfth lens (L12), a thirteenth lens (L13), a fourteenth lens (L14), and a fifteenth lens (L15) arranged in sequence along the optical axis, wherein the eighth lens (L8), the tenth lens (L10), the eleventh lens (L11), the twelfth lens (L12), and the fifteenth lens (L15) are positive lenses, and the ninth lens (L9), the thirteenth lens (L13), and the fourteenth lens (L14) are negative lenses.

2. The large aperture wide-angle lens according to claim 1, characterized in that: The first lens (L1) is a meniscus lens with its convex surface facing the object plane; the second lens (L2) is a meniscus lens with its convex surface facing the object plane; the third lens (L3) is a meniscus lens with its convex surface facing the object plane; the fourth lens (L4) is a biconvex lens; the fifth lens (L5) is a biconcave lens; the sixth lens (L6) is a biconvex lens; the seventh lens (L7) is a meniscus lens with its convex surface facing the object plane; the eighth lens ( The ninth lens (L8) is a biconvex lens; the ninth lens (L9) is a biconcave lens; the tenth lens (L10) is a biconvex lens; the eleventh lens (L11) is a biconvex lens; the twelfth lens (L12) is a biconvex lens; the thirteenth lens (L13) is a meniscus lens with its convex surface facing the image plane; the fourteenth lens (L14) is a meniscus lens with its convex surface facing the object plane; and the fifteenth lens (L15) is a meniscus lens with its convex surface facing the object plane.

3. The large aperture wide-angle lens according to claim 2, characterized in that: The ninth lens (L9) and the tenth lens (L10) are combined into a cemented lens.

4. The large aperture wide-angle lens according to claim 2, characterized in that: The twelfth lens (L12) and the thirteenth lens (L13) are combined into a cemented lens.

5. The large aperture wide-angle lens according to claim 1, characterized in that: The large aperture wide-angle lens satisfies the following relationship F1 / F =7.04,F1=140.83; F2 / F =-1.57,F2=-31.51; F3 / F =-2.22,F3=-44.58; F4 / F =2.13,F4=42.68; F5 / F =-1.88,F5=-37.67; F6 / F =1.61,F6=32.1; F7 / F =18.15,F7=363.10; F8 / F =4.13,F8=82.76; F 9-10 / F =-1.69,F 9-10 =-33.98; F 11 / F =2.14,F 11 =42.98; F 12-13 / F =3.91,F 12-13 =78.39; F 14 / F =-6.1,F 14 =-122.21; F 15 / F =10.21,F 15 =204.25; F G1 / F =-0.9,F G1 =-18.53; F G2 / F =1.66,F G2 =28.01; F G3 / F =2.24,F G3 =44.82; Where F is the effective focal length of the lens, F1 is the focal length of the first lens (L1), F2 is the focal length of the second lens (L2), F3 is the focal length of the third lens (L3), F4 is the focal length of the fourth lens (L4), F5 is the focal length of the fifth lens (L5), F6 is the focal length of the sixth lens (L6), F7 is the focal length of the seventh lens (L7), F8 is the focal length of the eighth lens (L8), F 9-10 is the combined focal length of the cemented lens composed of the ninth lens (L9) and the tenth lens (L10), F 11 is the focal length of the eleventh lens (L11), F 12-13 is the combined focal length of the cemented lens composed of the twelfth lens (L12) and the thirteenth lens (L13), F 14 is the focal length of the fourteenth lens (L14), F 15 is the focal length of the fifteenth lens (L15), F G1 is the combined focal length of the first lens group (G1), F G2 is the combined focal length of the second lens group (G2), F G3 is the combined focal length of the third lens group (G3).

6. The large aperture wide-angle lens according to claim 1, characterized in that: The focal length F of the large aperture wide-angle lens and the total optical length L of the large aperture wide-angle lens satisfy the relationship: 5.5≤F / L≤8.

5.

7. The large aperture wide-angle lens according to claim 1, characterized in that: The tenth lens (L10) is made of low-dispersion ED material, and the difference in Abbe number between the tenth lens (L10) and the ninth lens (L9) is greater than or equal to 40.

8. The large aperture wide-angle lens according to claim 1, characterized in that: The first lens group (G1), the second lens group (G2), and the third lens group (G3) all use glass lenses.

9. The large aperture wide-angle lens according to claim 1, characterized in that: A filter group and / or protective glass is provided between the fifteenth lens (L15) and the image side.

10. The large aperture wide-angle lens according to claim 1, characterized in that: The large aperture wide-angle lens has a focal length of F=20 mm, an aperture value FNO=1.8, and a field of view of 94.94°.

Images