Large-aperture wide-angle lens

Abstract

The invention discloses a large-aperture wide-angle lens. The large-aperture wide-angle lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens from an object side to an image side along an optical axis, the first to ninth lenses are spherical lenses. The fifth lens and the sixth lens are glued to form a first doublet lens, and the eighth lens and the ninth lens are glued to form a second doublet lens; the first lens has negative focal power, the second lens has negative focal power, the third lens has positive focal power, the fourth lens has positive focal power, the fifth lens has positive focal power, the sixth lens has positive focal power, the seventh lens has positive focal power, the eighth lens has positive focal power, and the ninth lens has negative focal power. The large-aperture wide-angle lens can realize large wide angle, large aperture and low cost.

Description

Technical Field

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

[0002] A wide-angle lens is a lens with a short focal length and a wide field of view. Its unique optical properties make it suitable for use in fields such as photography, videography, and vehicle monitoring.

[0003] However, to ensure the imaging effect of a wide-angle lens, a large number of lenses are generally required, which undoubtedly makes the lens structure complex and the cost high. With the demand for lenses with large apertures, there is a need to provide a wide-angle lens with a large wide angle, large aperture and low cost. Summary of the Invention

[0004] In view of the above problems, an object of the present invention is to provide a large aperture wide-angle lens, which can achieve a large wide angle, a large aperture and low cost. The present invention provides a large aperture wide-angle lens, which includes, along the optical axis from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens; the first lens to the ninth lens are all spherical lenses; the fifth lens and the sixth lens are cemented together to form a first doublet lens, and the eighth lens and the ninth lens are cemented together to form a second doublet lens; the first lens has negative optical power, the second lens has negative optical power, the third lens has positive 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 positive optical power, and the ninth lens has negative optical power.

[0005] Optionally, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: <f1 / f2<2。

[0006] Optionally, the curvature radius L1R1 of the object side surface of the first lens and the curvature radius L1R2 of the image side surface of the first lens satisfy the following relationship: <L1R1 / L1R2<15。

[0007] Optionally, the thickness H13 of the sixth lens and the thickness H17 of the eighth lens satisfy the following relationship: 0.5 <H13 / H17<1.5。

[0008] Optionally, the focal length f6 of the sixth lens and the focal length f8 of the eighth lens satisfy the following relationship: 0.4 <f6 / f8<2。

[0009] Optionally, a curvature radius L8R1 of the object-side surface of the eighth lens and a curvature radius L8R2 of the image-side surface of the eighth lens satisfy the following relationship: -0.5 mm<|L8R1|-|L8R2|<1.5 mm.

[0010] Optionally, the Abbe number Ab1 of the first lens satisfies: 35 <Ab1。

[0011] Optionally, the focal length f1 of the first lens, the focal length f2 of the second lens, and the focal length f3 of the third lens satisfy: f1+f2+f3<0 mm.

[0012] Optionally, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens, the focal length f6 of the sixth lens, the focal length f7 of the seventh lens, the focal length f8 of the eighth lens and the focal length f9 of the ninth lens satisfy: 0 mm <f4+f5+f6+f7+f8+f9。

[0013] Optionally, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: 0.45≤f3 / f4≤1.25.

[0014] The large aperture wide-angle lens provided by the present invention includes, along the optical axis from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens. The first to ninth lenses are all spherical lenses. The fifth lens and the sixth lens are cemented together to form a first doublet lens, and the eighth lens and the ninth lens are cemented together to form a second doublet lens. The first lens has a negative optical power, the second lens has a negative optical power, the third lens has a positive optical power, the fourth lens has a positive optical power, the fifth lens has a negative optical power, the sixth lens has a positive optical power, the seventh lens has a positive optical power, the eighth lens has a positive optical power, and the ninth lens has a negative optical power. The fifth lens and the sixth lens are cemented together to form a first doublet lens, and the eighth lens and the ninth lens are cemented together to form a second doublet lens. The cemented arrangement can reduce the overall volume of the lens, and during assembly, the two lenses can be installed by placing them once. By distributing the optical power of the first through ninth lenses and rationally allocating the power, spacing / thickness, refractive index, and Abbe number of each lens, a wide-angle lens with a large aperture and excellent image quality can be achieved. Furthermore, since the wide-angle lens utilizes only nine spherical lenses, the number of lenses used is reduced, contributing to a compact size and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic structural diagram of a large aperture wide-angle lens according to an embodiment of the present application is shown.

[0017] Figure 2 A schematic structural diagram of a large aperture wide-angle lens according to Example 1 of the present application is shown.

[0018] Figures 3 to 5 The MTF curve, distortion diagram, and relative illumination and Y field of view diagram of the large aperture wide-angle lens of Example 1 are respectively shown.

[0019] Figure 6 A schematic structural diagram of a large aperture wide-angle lens according to Example 2 of the present application is shown.

[0020] Figures 7 to 9 The MTF curve, distortion diagram, and relative illumination and Y field of view diagram of the large aperture wide-angle lens of Example 2 are respectively shown.

[0021] Figure 10 A schematic structural diagram of a large aperture wide-angle lens according to Example 3 of the present application is shown.

[0022] Figures 11 to 13 The MTF curve, distortion diagram, and relative illumination and Y field of view diagram of the large aperture wide-angle lens of Example 3 are respectively shown. DETAILED DESCRIPTION

[0023] The aforementioned and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the drawings. Through the description of the specific embodiments, a deeper and more specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are only for reference and illustration purposes and are not intended to limit the present invention. Some well-known parts may not be shown. In the various drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the drawings are not necessarily drawn strictly according to the actual scale.

[0024] It should be understood that the terms "first," "second," "third," and "fourth," etc., are intended solely to distinguish between components or circuits having similar properties, and do not indicate or imply relative importance or a particular order. The terms "comprise," "include," or any other variation thereof, are intended to encompass a non-exclusive inclusion, meaning that in addition to the listed elements, other elements not explicitly listed may also be included.

[0025] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0026] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the image plane is called the image-side surface of the lens.

[0027] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] The features, principles and other aspects of the present application are described in detail below.

[0029] Figure 1 A schematic structural diagram of a large aperture wide-angle lens according to an embodiment of the present application is shown.

[0030] The large-aperture wide-angle lens according to the exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. Lenses L1 through L9 are all spherical lenses. The fifth lens L5 and the sixth lens L6 are cemented together to form a first doublet, and the eighth lens L8 and the ninth lens L9 are cemented together to form a second doublet. The first lens L1 has negative optical power, the second lens L2 has negative optical power, the third lens L3 has positive optical power, the fourth lens L4 has positive optical power, the fifth lens L5 has negative optical power, the sixth lens L6 has positive optical power, the seventh lens L7 has positive optical power, the eighth lens L8 has positive optical power, and the ninth lens L9 has negative optical power. The fifth lens L5 and the sixth lens L6 are cemented together to form a first doublet, while the eighth lens L8 and the ninth lens L9 are cemented together to form a second doublet. This cemented arrangement reduces the overall size of the lens and allows both lenses to be installed in a single placement during assembly. Based on the power distribution of the first through ninth lenses L1 through L9, and by rationally allocating the power, spacing / thickness, refractive index, and Abbe number of each lens, a wide-angle lens with a large aperture and excellent image quality can be achieved. Furthermore, the large-aperture wide-angle lens utilizes only nine spherical lenses, reducing the number of lenses used and contributing to a compact size and low cost.

[0031] In an exemplary embodiment, the large aperture wide-angle lens according to the present application further includes an aperture STO. The aperture STO can be set between adjacent lenses. For example, the aperture STO is set between the third lens L3 and the fourth lens L4. Then, the nine lenses can be divided into two groups with the aperture as the boundary. The first group of lenses includes the first lens L1 to the third lens L3, and the second group of lenses includes the fourth lens L4 to the ninth lens L9. The aperture STO can control the amount of light entering the optical system through the first group of lenses and limit the angle of the incident light beam, which helps to optimize the imaging quality. In addition, the aperture STO can optimize the large-angle incident light beam control of the first group of lenses, so that the second group of lenses can converge light and control aberrations at a large clear aperture, thereby realizing a system with a large aperture, such as 1.4.

[0032] In an exemplary embodiment, according to the large aperture wide-angle lens of the present application, the first lens L1 is a meniscus spherical lens with negative optical power; the second lens L2 is a biconcave spherical lens with negative optical power; the third lens L3 is a biconvex spherical lens with positive optical power; the fourth lens L4 is a biconvex spherical lens with positive optical power; the sixth lens L6 is a biconvex spherical lens with positive optical power; the seventh lens L7 is a plano-convex spherical lens with positive optical power; and the eighth lens L8 is a biconvex spherical lens with positive optical power.

[0033] In an exemplary embodiment, for the large-aperture wide-angle lens according to the present application, the materials of the first lens L1 to the ninth lens L9 can be glass, plastic, or a combination of glass and plastic, etc. Preferably, the materials of the first lens L1 to the ninth lens L9 are glass. Glass has better temperature stability than plastic, which can avoid the focal length shift or defocus of the optical system caused by the expansion of each lens made of plastic due to temperature changes.

[0034] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy 0 < f1 / f2 < 2; where the focal length of the first lens L1 is f1, and the focal length of the second lens L2 is f2. Satisfying 0 < f1 / f2 < 2, and both the first lens L1 and the second lens L2 have negative optical powers, can effectively diverge light rays, expand the incident angle, and by controlling the ratio range of the focal length f1 of the first lens L1 to the focal length f2 of the second lens L2, it is beneficial to converge light rays with a large viewing angle, enabling the lens to have a large field of view, such as 140°.

[0035] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy 2 < L1R1 / L1R2 < 15; where the curvature radius of the object side of the first lens L1 is L1R1, and the curvature radius of the image side of the first lens L1 is L1R2. Satisfying 2 < L1R1 / L1R2 < 15, by controlling the ratio range of the curvature radius L1R1 of the object side of the first lens L1 to the curvature radius L1R2 of the image side of the first lens L1, it is beneficial to converge light rays with a large viewing angle, enabling the lens to have a large field of view, such as 140°.

[0036] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy 0.5 < H13 / H17 < 1.5; where the thickness of the sixth lens L6 is H13, and the thickness of the eighth lens L8 is H17. Satisfying 0.5 < H13 / H17 < 1.5, by controlling the ratio range of the thickness H13 of the sixth lens L six to the thickness H17 of the eighth lens L8, it is beneficial for spherical aberration correction, meeting the imaging quality requirements under large-aperture conditions, and enabling the lens to have a large aperture.

[0037] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy 0.4 < f6 / f8 < 2; where the focal length of the sixth lens L6 is f6, and the focal length of the eighth lens L8 is f8. Satisfying 0.4 < f6 / f8 < 2, by controlling the ratio range of the focal length f6 of the sixth lens L6 to the focal length f8 of the eighth lens L8, it is beneficial for chromatic aberration correction and improving the imaging quality of the system.

[0038] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy -0.5 mm < |L8R1| - |L8R2| < 1.5 mm; where, the radius of curvature of the object side surface of the eighth lens L8 is L8R1, and the radius of curvature of the image side surface of the eighth lens L8 is L8R2. Satisfying -0.5 mm < |L8R1| - |L8R2| < 1.5 mm, by controlling the absolute value difference range between the radius of curvature L8R1 of the object side surface of the eighth lens L8 and the radius of curvature L8R2 of the image side surface of the eighth lens L8, it is beneficial to the processing and assembly of the lens.

[0039] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy 35 < Ab1; where, the Abbe number of the first lens L1 is Ab1. Satisfying 35 < Ab1, by controlling the value range of the Abbe number Ab1 of the first lens L1, it is beneficial to correcting chromatic aberration and improving the imaging quality of the system.

[0040] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy f1 + f2 + f3 < 0 mm; where, the focal length of the first lens L1 is f1, the focal length of the second lens L2 is f2, and the focal length of the third lens L3 is f3. Satisfying f1 + f2 + f3 < 0 mm, by controlling the value range of the sum of the focal length f1 of the first lens L1, the focal length f2 of the second lens L2, and the focal length f3 of the third lens L3, it is beneficial to converging light rays with a large viewing angle and realizing that the lens has a large field angle.

[0041] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy 0 mm < f4 + f5 + f6 + f7 + f8 + f9; where, the focal length of the fourth lens L4 is f4, the focal length of the fifth lens L5 is f5, the focal length of the sixth lens L6 is f6, the focal length of the seventh lens L7 is f7, the focal length of the eighth lens L8 is f8, and the focal length of the ninth lens L9 is f9. Satisfying 0 mm < f4 + f5 + f6 + f7 + f8 + f9, by controlling the value range of the sum of the focal length f4 of the fourth lens L4, the focal length f5 of the fifth lens L5, the focal length f6 of the sixth lens L6, the focal length f7 of the seventh lens L7, the focal length f8 of the eighth lens L8, and the focal length f9 of the ninth lens L9, it is beneficial to correcting chromatic aberration and improving the imaging quality of the system.

[0042] In an exemplary embodiment, the large-aperture wide-angle lens according to the present application can satisfy 0.45 ≤ f3 / f4 ≤ 1.25; where, the focal length of the third lens L3 is f3, and the focal length of the fourth lens L4 is f4. Satisfying 0.45 ≤ f3 / f4 ≤ 1.25, by controlling the ratio range of the focal length f3 of the third lens L3 and the focal length f4 of the fourth lens L4 within a certain range, it helps to share the deflection angle of the light rays incident into the system, reduce spherical aberration and coma, and improve the imaging quality of the system.

[0043] In an exemplary embodiment, the large aperture wide-angle lens according to the present application can satisfy 0.5 ≤ H13 / H17 ≤ 1.2; wherein the thickness of the sixth lens element L6 is H13, and the thickness of the eighth lens element L8 is H17. By controlling the ratio of the thickness H13 of the sixth lens element L6 to the thickness H17 of the eighth lens element L8 within the range of 0.5 ≤ H13 / H17 ≤ 1.2, the system structure is more symmetrical, the impact of thickness tolerance and refractive index tolerance on image quality is reduced, and the imaging quality of the system is improved.

[0044] In exemplary embodiments, the large aperture wide-angle lens according to the present application further includes an IR filter for correcting chromatic aberration and / or a protective glass for protecting the photosensitive element located on the imaging surface IMG. In one exemplary embodiment, the IR filter and / or the protective glass may be disposed between the ninth lens element L9 and the imaging surface IMG.

[0045] Based on the same inventive concept, an electronic device according to an exemplary embodiment of the present application includes the aforementioned large-aperture, wide-angle lens. The electronic device may be, but is not limited to, a smartphone, a tablet computer, a laptop computer, a pan / tilt camera, a surveillance camera, an in-vehicle monitoring device, or other imaging device. The implementation of this electronic device can be referenced in the embodiments of the large-aperture, wide-angle lens, and any repetitions will not be repeated.

[0046] However, those skilled in the art will appreciate that the number of lenses comprising the optical imaging lens can be varied to achieve the various results and advantages described herein without departing from the claimed technical solutions. For example, while nine lenses are described in the embodiments, the optical imaging lens is not limited to nine lenses. If desired, the optical imaging lens may also include other numbers of lenses.

[0047] Specific embodiments of a large aperture wide-angle lens applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0048] Example 1 The following reference Figure 2 A large aperture wide-angle lens according to Example 1 of the present application is described. Figure 2 A schematic structural diagram of a large aperture wide-angle lens according to Example 1 of the present application is shown.

[0049] like Figure 2As shown, this large-aperture wide-angle lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. Lenses L1 through L9 are all spherical lenses; the fifth lens L5 and the sixth lens L6 are cemented together to form a first doublet, and the eighth lens L8 and the ninth lens L9 are cemented together to form a second doublet. A stop STO may be positioned between the third lens L3 and the fourth lens L4. A filter IR may be positioned between the ninth lens L9 and the imaging plane IMG.

[0050] Please also refer to the following Figure 2 As shown in Table 1, the first lens L1 has negative power, with a convex object-side surface and a concave image-side surface. The second lens L2 has negative power, with a concave object-side surface and a concave image-side surface. The third lens L3 has positive power, with a convex object-side surface and a convex image-side surface. The fourth lens L4 has positive power, with a convex object-side surface and a convex image-side surface. The fifth lens L5 has negative power, with a convex object-side surface and a concave image-side surface. The sixth lens L6 has positive power, with a convex object-side surface and a convex image-side surface. The seventh lens L7 has positive power, with a convex object-side surface and a flat image-side surface. The eighth lens L8 has positive power, with a convex object-side surface and a convex image-side surface. The ninth lens L9 has negative power, with a concave object-side surface and a concave image-side surface. Filter IR has an object-side surface and an image-side surface. The light can pass through the first lens L1, the second lens L2, the third lens L3, the aperture STO, 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 filter IR in sequence, and finally form an image on the imaging surface IMG.

[0051] Table 1 shows the basic parameters of the large aperture wide-angle lens of Example 1, wherein the units of the curvature radius, pitch / thickness and focal length are all millimeters (mm).

[0052] Table 1:

[0053] Among them, L1-R1 represents the object-side surface of the first lens L1, and L1-R2 represents the image-side surface of the first lens L1; L2-R1 represents the object-side surface of the second lens L2, and L2-R2 represents the image-side surface of the second lens L2; ​​L3-R1 represents the object-side surface of the third lens L3, and L3-R2 represents the image-side surface of the third lens L3; L4-R1 represents the object-side surface of the fourth lens L4, and L4-R2 represents the image-side surface of the fourth lens L4; L5-R1 represents the object-side surface of the fifth lens L5, and L5-R2 is the cemented surface of the fifth lens L5 and the sixth lens L6, which represents the fifth lens The image-side surface of L5 also represents the object-side surface of the sixth lens element L6, and L6-R2 represents the image-side surface of the sixth lens element L6; L7-R1 represents the object-side surface of the seventh lens element L7, and L7-R2 represents the image-side surface of the seventh lens element L7; L8-R1 represents the object-side surface of the eighth lens element L8, L8-R2 is the cemented surface between the eighth lens element L8 and the ninth lens element L9, and represents the image-side surface of the eighth lens element L8, and also represents the object-side surface of the ninth lens element L9; L9-R2 represents the image-side surface of the ninth lens element L9; IR-R1 represents the object-side surface of the optical filter IR, and IR-R2 represents the image-side surface of the optical filter IR.

[0054] In Embodiment 1, according to the refractive power distribution of the first lens L1 to the ninth lens L9 in Table 1, and by reasonably allocating the refractive power, spacing / thickness, refractive index, Abbe number, etc. of each lens, a large wide-angle, large aperture, and good imaging quality can be achieved. Moreover, the large aperture wide-angle lens only uses nine spherical lenses, so the number of lenses used is small, which is conducive to achieving a small volume and low cost. Among them, the focal length of the large aperture wide-angle lens is 3.25 mm, the aperture F is 1.4, the imaging circle diameter is 6.92 mm, the field angle is 140°, and the working band is 420~680 nm. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 / f2 = 0.88, satisfying: 0 < f1 / f2 < 2. The relationship between the curvature radius L1R1 of the object side of the first lens L1 and the curvature radius L1R2 of the image side of the first lens L1 is L1R1 / L1R2 = 9.19, satisfying: 2 < L1R1 / L1R2 < 15. The relationship between the thickness H13 of the sixth lens L6 and the thickness H17 of the eighth lens L8 is H13 / H17 = 0.79, satisfying: 0.5 < H13 / H17 < 1.5, and also satisfying: 0.5 ≤ H13 / H17 ≤ 1.2. The relationship between the focal length f6 of the sixth lens L6 and the focal length f8 of the eighth lens L8 is f6 / f8 = 1.28, satisfying: 0.4 < f6 / f8 < 2. The relationship between the curvature radius L8R1 of the object side of the eighth lens L8 and the curvature radius L8R2 of the image side of the eighth lens L8 is |L8R1| - |L8R2| = -0.02 mm, satisfying: -0.5 mm < |L8R1| - |L8R2| < 1.5 mm. The Abbe number Ab1 of the first lens L1 is Ab1 = 44.10, satisfying: 35 < Ab1. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 + f2 + f3 = -6.64 mm, satisfying: f1 + f2 + f3 < 0 mm. The relationship between the focal length f4 of the fourth lens L4, the focal length f5 of the fifth lens L5, the focal length f6 of the sixth lens L6, the focal length f7 of the seventh lens L7, the focal length f8 of the eighth lens L8, and the focal length f9 of the ninth lens L9 is f4 + f5 + f6 + f7 + f8 + f9 = 60.20 mm, satisfying: 0 mm < f4 + f5 + f6 + f7 + f8 + f9. The relationship between the focal length f3 of the third lens L3 and the focal length f4 of the fourth lens L4 is f3 / f4 = 0.71, satisfying: 0.45 ≤ f3 / f4 ≤ 1.25.

[0055] Figure 3The MTF curve of the large aperture wide-angle lens of Example 1 is shown, as is the MTF (Modulation Transfer Function) curve. The MTF curve shows how the imaging system transmits image detail (i.e., image contrast) at different spatial frequencies. At a spatial frequency of 180 lp / mm, the OTF modulus is greater than 0.1, indicating excellent resolution. Figure 4 The distortion diagram of the large aperture wide-angle lens of Example 1 is shown. The distortion is less than 20%, which is very well corrected. Figure 5 The relative illumination and Y field of view of the large aperture wide-angle lens of Example 1 are shown. The relative illumination is greater than 0.8, and the illumination of the picture is uniform. Figures 3 to 5 It can be seen that the large aperture wide-angle lens provided in Example 1 has good resolution, good correction, uniform image illumination, and can achieve good imaging quality.

[0056] Example 2 The following reference Figure 6 A large aperture wide-angle lens according to Example 2 of the present application is described. Figure 6 A schematic structural diagram of a large aperture wide-angle lens according to Example 2 of the present application is shown.

[0057] like Figure 6 As shown, this large-aperture wide-angle lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. Lenses L1 through L9 are all spherical lenses; the fifth lens L5 and the sixth lens L6 are cemented together to form a first doublet, and the eighth lens L8 and the ninth lens L9 are cemented together to form a second doublet. A stop STO may be positioned between the third lens L3 and the fourth lens L4. A filter IR may be positioned between the ninth lens L9 and the imaging plane IMG.

[0058] Please also refer to the following Figure 6As shown in Table 2, the first lens L1 has negative power, with a convex object-side surface and a concave image-side surface. The second lens L2 has negative power, with a concave object-side surface and a concave image-side surface. The third lens L3 has positive power, with a convex object-side surface and a convex image-side surface. The fourth lens L4 has positive power, with a convex object-side surface and a convex image-side surface. The fifth lens L5 has negative power, with a concave object-side surface and a concave image-side surface. The sixth lens L6 has positive power, with a convex object-side surface and a convex image-side surface. The seventh lens L7 has positive power, with a convex object-side surface and a flat image-side surface. The eighth lens L8 has positive power, with a convex object-side surface and a convex image-side surface. The ninth lens L9 has negative power, with a concave object-side surface and a convex image-side surface. Filter IR has an object-side surface and an image-side surface. The light can pass through the first lens L1, the second lens L2, the third lens L3, the aperture STO, 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 filter IR in sequence, and finally form an image on the imaging surface IMG.

[0059] Table 2 shows the basic parameters of the large aperture wide-angle lens of Example 2, wherein the units of the curvature radius, pitch / thickness and focal length are all millimeters (mm).

[0060] Table 2:

[0061] In Embodiment 2, according to the optical power distribution of the first lens L1 to the ninth lens L9 in Table 2, and by reasonably allocating the optical power, spacing / thickness, refractive index, Abbe number, etc. of each lens, a large wide-angle, large aperture and good imaging quality can be achieved. Moreover, the large aperture wide-angle lens only uses nine spherical lenses, so the number of lenses used is small, which is beneficial to achieving a small volume and low cost. Among them, the focal length of the large aperture wide-angle lens is 3.25 mm, the aperture F is 1.4, the imaging circle diameter is 6.91 mm, the field angle is 140°, and the working wavelength band is 420~680 nm. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 / f2 = 0.95, satisfying: 0 < f1 / f2 < 2. The relationship between the curvature radius L1R1 of the object side of the first lens L1 and the curvature radius L1R2 of the image side of the first lens L1 is L1R1 / L1R2 = 6.82, satisfying: 2 < L1R1 / L1R2 < 15. The relationship between the thickness H13 of the sixth lens L6 and the thickness H17 of the eighth lens L8 is H13 / H17 = 0.75, satisfying: 0.5 < H13 / H17 < 1.5, and also satisfying: 0.5 ≤ H13 / H17 ≤ 1.2. The relationship between the focal length f6 of the sixth lens L6 and the focal length f8 of the eighth lens L8 is f6 / f8 = 0.46, satisfying: 0.4 < f6 / f8 < 2. The relationship between the curvature radius L8R1 of the object side of the eighth lens L8 and the curvature radius L8R2 of the image side of the eighth lens L8 is |L8R1| - |L8R2| = 0.83 mm, satisfying: -0.5 mm < |L8R1| - |L8R2| < 1.5 mm. The Abbe number Ab1 of the first lens L1 is Ab1 = 48.40, satisfying: 35 < Ab1. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 + f2 + f3 = -5.09 mm, satisfying: f1 + f2 + f3 < 0 mm. The relationship between the focal length f4 of the fourth lens L4, the focal length f5 of the fifth lens L5, the focal length f6 of the sixth lens L6, the focal length f7 of the seventh lens L7, the focal length f8 of the eighth lens L8 and the focal length f9 of the ninth lens L9 is f4 + f5 + f6 + f7 + f8 + f9 = 48.87 mm, satisfying: 0 mm < f4 + f5 + f6 + f7 + f8 + f9. The relationship between the focal length f3 of the third lens L3 and the focal length f4 of the fourth lens L4 is f3 / f4 = 0.88, satisfying: 0.45 ≤ f3 / f4 ≤ 1.25.

[0062] Figure 7The MTF curve of the large aperture wide-angle lens of Example 2 is shown, as well as the MTF (Modulation Transfer Function) curve. The MTF curve shows how the imaging system transmits image detail (i.e., image contrast) at different spatial frequencies. At a spatial frequency of 180 lp / mm, the OTF modulus is greater than 0.1, indicating excellent resolution. Figure 8 The distortion diagram of the large aperture wide-angle lens of Example 2 is shown. The distortion is less than 20%, which is very well corrected. Figure 9 The relative illumination and Y field of view of the large aperture wide-angle lens of Example 2 are shown. The relative illumination is greater than 0.8, and the illumination of the picture is uniform. Figures 7 to 9 It can be seen that the large aperture wide-angle lens provided in Example 2 has good resolution, good correction, uniform image illumination, and can achieve good imaging quality.

[0063] Example 3 The following reference Figure 10 A large aperture wide-angle lens according to Example 3 of the present application will be described. Figure 10 A schematic structural diagram of a large aperture wide-angle lens according to Example 3 of the present application is shown.

[0064] like Figure 10 As shown, this large-aperture wide-angle lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. Lenses L1 through L9 are all spherical lenses; the fifth lens L5 and the sixth lens L6 are cemented together to form a first doublet, and the eighth lens L8 and the ninth lens L9 are cemented together to form a second doublet. A stop STO may be positioned between the third lens L3 and the fourth lens L4. A filter IR may be positioned between the ninth lens L9 and the imaging plane IMG.

[0065] Please also refer to the following Figure 10As shown in Table 3, the first lens L1 has negative power, with a convex object-side surface and a concave image-side surface. The second lens L2 has negative power, with a concave object-side surface and a concave image-side surface. The third lens L3 has positive power, with a convex object-side surface and a convex image-side surface. The fourth lens L4 has positive power, with a convex object-side surface and a convex image-side surface. The fifth lens L5 has negative power, with a concave object-side surface and a concave image-side surface. The sixth lens L6 has positive power, with a convex object-side surface and a convex image-side surface. The seventh lens L7 has positive power, with a convex object-side surface and a flat image-side surface. The eighth lens L8 has positive power, with a convex object-side surface and a convex image-side surface. The ninth lens L9 has negative power, with a concave object-side surface and a concave image-side surface. Filter IR has an object-side surface and an image-side surface. The light can pass through the first lens L1, the second lens L2, the third lens L3, the aperture STO, 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 filter IR in sequence, and finally form an image on the imaging surface IMG.

[0066] Table 3 shows the basic parameters of the large aperture wide-angle lens of Example 3, wherein the units of the curvature radius, pitch / thickness and focal length are all millimeters (mm).

[0067] Table 3:

[0068] In Embodiment 3, according to the refractive power distribution of the first lens L1 to the ninth lens L9 in Table 3, and by reasonably allocating the refractive power, spacing / thickness, refractive index, Abbe number, etc. of each lens, a large wide-angle, large aperture, and good imaging quality can be achieved. Moreover, the large-aperture wide-angle lens only uses nine spherical lenses, so the number of lenses used is small, which is conducive to achieving a small volume and low cost. Among them, the focal length of the large-aperture wide-angle lens is 3.25 mm, the aperture F is 1.4, the imaging circle diameter is 6.91 mm, the field angle is 140°, and the working wavelength range is 420~680 nm. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 / f2 = 0.92, satisfying 0 < f1 / f2 < 2. The relationship between the curvature radius L1R1 of the object side of the first lens L1 and the curvature radius L1R2 of the image side of the first lens L1 is L1R1 / L1R2 = 8.41, satisfying 2 < L1R1 / L1R2 < 15. The relationship between the thickness H13 of the sixth lens L6 and the thickness H17 of the eighth lens L8 is H13 / H17 = 0.81, satisfying 0.5 < H13 / H17 < 1.5 and also satisfying 0.5 ≤ H13 / H17 ≤ 1.2. The relationship between the focal length f6 of the sixth lens L6 and the focal length f8 of the eighth lens L8 is f6 / f8 = 0.64, satisfying 0.4 < f6 / f8 < 2. The relationship between the curvature radius L8R1 of the object side of the eighth lens L8 and the curvature radius L8R2 of the image side of the eighth lens L8 is |L8R1| - |L8R2| = -0.14 mm, satisfying -0.5 mm < |L8R1| - |L8R2| < 1.5 mm. The Abbe number Ab1 of the first lens L1 is Ab1 = 53.90, satisfying 35 < Ab1. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 + f2 + f3 = -5.23 mm, satisfying f1 + f2 + f3 < 0 mm. The relationship between the focal length f4 of the fourth lens L4, the focal length f5 of the fifth lens L5, the focal length f6 of the sixth lens L6, the focal length f7 of the seventh lens L7, the focal length f8 of the eighth lens L8, and the focal length f9 of the ninth lens L9 is f4 + f5 + f6 + f7 + f8 + f9 = 52.57 mm, satisfying 0 mm < f4 + f5 + f6 + f7 + f8 + f9. The relationship between the focal length f3 of the third lens L3 and the focal length f4 of the fourth lens L4 is f3 / f4 = 0.91, satisfying 0.45 ≤ f3 / f4 ≤ 1.25.

[0069] Figure 11The MTF curve of the large aperture wide-angle lens of Example 3 is shown, as well as the MTF (Modulation Transfer Function) curve. The MTF curve shows how the imaging system transmits image detail (i.e., image contrast) at different spatial frequencies. At a spatial frequency of 180 lp / mm, the OTF modulus is greater than 0.1, indicating excellent resolving power. Figure 12 The distortion diagram of the large aperture wide-angle lens of Example 3 is shown. The distortion is less than 20%, which is very well corrected. Figure 13 The relative illumination and Y field of view of the large aperture wide-angle lens of Example 3 are shown. The relative illumination is greater than 0.8, and the illumination of the picture is uniform. Figures 11 to 13 It can be seen that the large aperture wide-angle lens provided in Example 3 has good resolution, good correction, uniform image illumination, and can achieve good imaging quality.

[0070] In summary, Example 1, Example 2, and Example 3 respectively satisfy the relationships shown in Table 4.

[0071] Table 4:

[0072] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A large aperture wide-angle lens, characterized in that: The optical system includes, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens. The first to ninth lenses are all spherical lenses. The fifth lens and the sixth lens are cemented together to form a first doublet lens. The eighth lens and the ninth lens are cemented together to form a second doublet lens. The first lens has negative optical power, the second lens has negative optical power, the third lens has positive 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 positive optical power, and the ninth lens has negative optical power.

2. The large aperture wide-angle lens according to claim 1, characterized in that: The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: <f1 / f2<2。 3. The large aperture wide-angle lens according to claim 1, characterized in that: The curvature radius L1R1 of the object side surface of the first lens and the curvature radius L1R2 of the image side surface of the first lens satisfy: <L1R1 / L1R2<15。 4. The large aperture wide-angle lens according to claim 1, characterized in that: The thickness H13 of the sixth lens and the thickness H17 of the eighth lens satisfy: 0.5 <H13 / H17<1.5。 5. The large aperture wide-angle lens according to claim 1, characterized in that: The focal length f6 of the sixth lens and the focal length f8 of the eighth lens satisfy: 0.4 <f6 / f8<2。 6. The large aperture wide-angle lens according to claim 1, characterized in that: A curvature radius L8R1 of the object-side surface of the eighth lens and a curvature radius L8R2 of the image-side surface of the eighth lens satisfy the following relationship: -0.5 mm<|L8R1|-|L8R2|<1.5 mm.

7. The large aperture wide-angle lens according to claim 1, characterized in that: The Abbe number Ab1 of the first lens satisfies: 35 <Ab1。 8. The large aperture wide-angle lens according to claim 1, wherein: The focal length f1 of the first lens, the focal length f2 of the second lens, and the focal length f3 of the third lens satisfy: f1+f2+f3<0 mm.

9. The large aperture wide-angle lens according to claim 1, characterized in that: The focal length f4 of the fourth lens, the focal length f5 of the fifth lens, the focal length f6 of the sixth lens, the focal length f7 of the seventh lens, the focal length f8 of the eighth lens and the focal length f9 of the ninth lens satisfy: 0 mm <f4+f5+f6+f7+f8+f9。 10. The large aperture wide-angle lens according to claim 1, characterized in that: The focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy the following relationship: 0.45≤f3 / f4≤1.25.

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