Wide-angle prime lens

Abstract

This invention relates to a wide-angle fixed-focus lens, which, along the optical axis from the object side to the image side, sequentially includes 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, wherein the first lens, the third lens, and the eighth lens have negative optical power, the second lens, the fourth lens, the fifth lens, and the ninth lens have positive optical power, and the sixth lens and the seventh lens have opposite optical powers.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically to a wide-angle fixed-focus lens. Background Technology

[0002] With the development of optical technology, optical lenses are widely used in security monitoring, drone photography, mobile phone photography, machine vision, action cameras and other fields. However, a wide shooting angle, a large amount of light intake, and sufficiently high image resolution are often the challenges in lens development.

[0003] Currently, wide-angle prime lenses on the market have the following problems: (1) Wide-angle lenses are often very large and heavy; (2) Lenses that meet certain image quality requirements often have very small apertures; (3) Most wide-angle lenses do not have high-definition image quality.

[0004] In summary, it is currently difficult for wide-angle lenses on the market to simultaneously achieve ultra-wide-angle, large aperture, high resolution, and small size. Summary of the Invention

[0005] In view of this, the present invention aims to propose a wide-angle fixed-focus lens that solves the problem that current wide-angle lenses cannot simultaneously achieve ultra-wide angle, large aperture, high resolution and miniaturization.

[0006] This invention provides a wide-angle fixed-focus lens, which, along the optical axis from the object side to the image side, sequentially includes 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, the third lens, and the eighth lens have negative optical power, the second lens, the fourth lens, the fifth lens, and the ninth lens have positive optical power, and the sixth lens and the seventh lens have opposite optical powers.

[0007] In a preferred embodiment of the present invention, the first lens is a convex-concave lens, the second lens is a concave-convex lens, the third lens and the eighth lens are concave-concave lenses, the fourth lens is a lens with a convex object side, the fifth lens and the ninth lens are convex-convex lenses, the seventh lens is a lens with a convex image side, and the sixth lens is a convex-convex lens or a concave-concave lens.

[0008] In a preferred embodiment of the present invention, the effective focal length f1 of the first lens and the effective focal length f of the lens satisfy: -1.8≤f1 / f≤-1.4.

[0009] In a preferred embodiment of the present invention, the effective focal length f2 of the second lens and the effective focal length f of the lens satisfy: 3.0≤f2 / f≤10.6.

[0010] In a preferred embodiment of the present invention, the effective focal length f3 of the third lens and the effective focal length f of the lens satisfy: -2.2≤f3 / f≤-1.2.

[0011] In a preferred embodiment of the present invention, the effective focal length f4 of the fourth lens and the effective focal length f of the lens satisfy: 1.5≤f4 / f≤2.1.

[0012] In a preferred embodiment of the present invention, the effective focal length f5 of the fifth lens and the effective focal length f of the lens satisfy: 2.0≤f5 / f≤2.6.

[0013] In a preferred embodiment of the present invention, the effective focal length f6 of the sixth lens and the effective focal length f of the lens satisfy: -1.3≤f6 / f≤2.2.

[0014] In a preferred embodiment of the present invention, the effective focal length f7 of the seventh lens and the effective focal length f of the lens satisfy: -3.7≤f7 / f≤2.1.

[0015] In a preferred embodiment of the present invention, the effective focal length f8 of the eighth lens and the effective focal length f of the lens satisfy: -5.6≤f8 / f≤-1.0.

[0016] In a preferred embodiment of the present invention, the effective focal length f9 of the ninth lens and the effective focal length f of the lens satisfy: 1.4≤f9 / f≤3.5.

[0017] In a preferred embodiment of the present invention, the air gap C45 between the fourth lens and the fifth lens and the total optical length TTL of the lens satisfy the following condition: 0.0 ≤ C45 / TTL ≤ 0.1.

[0018] In a preferred embodiment of the present invention, the optical back focal length (BFL) of the lens and the optical total length (TTL) of the lens satisfy the following condition: 0.1 ≤ BFL / TTL ≤ 0.2.

[0019] In a preferred embodiment of the present invention, the effective focal length f of the lens and the total optical length TTL of the lens satisfy: 7.8≤TTL / f≤8.9.

[0020] In a preferred embodiment of the present invention, the combined effective focal length fa of the first lens, the second lens, the third lens, and the fourth lens satisfies the following condition:

[0021] -3.5≤fa / f≤3.0.

[0022] In a preferred embodiment of the present invention, the combined effective focal length fb of the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens and the effective focal length f of the lens satisfy: 2.1≤fb / f≤3.5.

[0023] In a preferred embodiment of the present invention, the maximum optical imaging height D of the lens and the effective focal length f of the lens satisfy: 1.2≤D / f≤1.6.

[0024] In a preferred embodiment of the present invention, the distance M1 from the object side of the first lens to the aperture stop and the total optical length TTL of the lens satisfy the following condition: 0.3≤M1 / TTL≤0.6.

[0025] In a preferred embodiment of the present invention, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -0.6≤f1 / f2≤-0.1.

[0026] In a preferred embodiment of the present invention, the focal length f1 of the first lens and the focal length f3 of the third lens satisfy: 0.6≤f1 / f3≤1.3.

[0027] In a preferred embodiment of the present invention, the core thickness CT1 of the first lens and the core thickness CT2 of the second lens satisfy: 3.5≤CT2 / CT1≤7.0.

[0028] In a preferred embodiment of the present invention, the core thickness CT8 of the eighth lens and the core thickness CT9 of the ninth lens satisfy: 3.2≤CT9 / CT8≤7.9.

[0029] The wide-angle fixed-focus lens of this invention employs nine lenses. By combining the optical power and shape of each lens, and through reasonable parameter settings, it can achieve a large aperture (FNO≤1.8), a large field of view (FOV≥160°), and high resolution (35 million pixels). At the same time, it can also achieve at least one of the following beneficial effects: a large image plane (the image target surface can reach 1 / 1.8”), a small angle of incidence of the lens principal ray (CRA<18°), no blurring at high and low temperatures (-40~85°), good aberration correction, high color reproduction, long service life, and miniaturization. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1This is a schematic diagram of the optical structure of a wide-angle fixed-focus lens according to the first embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the optical structure of a wide-angle fixed-focus lens according to a second embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the optical structure of a wide-angle fixed-focus lens according to a third embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the optical structure of a wide-angle fixed-focus lens according to the fourth embodiment of the present invention. Detailed Implementation

[0035] The description of the embodiments in this specification should be taken in conjunction with the accompanying drawings, which should form part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and may be indicated in a simplified or convenient manner. Furthermore, parts of the various structures in the drawings will be described separately; it is worth noting that elements not shown in the figures or not described in words are in a form known to those skilled in the art.

[0036] The descriptions of the embodiments herein, including any references to directions and orientations, are for ease of description only and should not be construed as limiting the scope of the invention. The following description of preferred embodiments involves combinations of features, which may exist independently or in combination; the invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.

[0037] In this invention, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object-side surface of the lens, and the surface of each lens closest to the imaging side is called the image-side surface of the lens.

[0038] like Figures 1-4 As shown, the wide-angle fixed-focus lens of this embodiment of the invention, along the optical axis from the object side to the image side, sequentially includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture stop STO, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a flat plate CG, and an image plane IM.

[0039] The first lens L1 is a convex-concave lens with negative optical power. This configuration helps to reduce the size of large-angle light rays, decrease the incident angle of light rays in the rear lens group, and is more conducive to the correction of aberrations in the rear lens group.

[0040] The second lens L2 is a concave-convex lens with positive optical power. This configuration helps to compensate for aberrations such as chromatic aberration and field curvature generated by the first lens L1, reducing the burden on the subsequent lens group to correct aberrations.

[0041] The third lens L3 is a concave-convex lens with negative optical power. This configuration further reduces the size of large-angle light rays, shares some of the negative optical power of the first lens L1, and is more conducive to improving relative illumination.

[0042] The fourth lens, L4, is a lens with positive optical power and a convex object side. This configuration helps to further reduce the angle of incidence of light in the outer field of view, which is beneficial for the lens to achieve a larger aperture.

[0043] The fifth lens, L5, is a convex-convex lens with positive optical power. This design facilitates the convergence of light rays, allowing diverging light rays entering the optical system from the front to smoothly enter the rear optical system, resulting in a smoother overall optical path, optimized aberrations, and improved lens resolution.

[0044] The aperture stop STO is positioned between the fourth lens L4 and the fifth lens L5. The fifth lens L5, positioned behind the aperture stop STO, can better correct aberrations introduced by the preceding lens groups, improving higher-order spherical and coma aberrations, and contributing to achieving high lens resolution and uniform overall resolution.

[0045] The sixth lens L6 is a convex-convex lens with positive optical power, while the seventh lens L7 is a concave-convex lens with negative optical power. This arrangement helps to lower the height of light entering the sixth lens L6 and allows the light converged by the sixth lens L6 to smoothly transition to the rear lens, thus improving resolving power. Furthermore, the seventh lens L7 can also collect the light passing through the sixth lens L6, resulting in a smoother light path transition. Alternatively, the sixth lens L6 can be a concave-concave lens with negative optical power, while the seventh lens L7 is a convex-convex lens with positive optical power. This arrangement helps maintain image stability under high and low temperature conditions and allows the diverging light passing through the sixth lens L6 to smoothly enter the rear lens, further improving resolving power.

[0046] The eighth lens, L8, is a concave-convex lens with negative optical power. This design facilitates a smooth light transition, allowing the lens to achieve a large target surface size.

[0047] The ninth lens, L9, is a convex-convex lens with positive optical power. This design helps to reduce the principal ray angle, thus matching the chip's CRA curve requirements. Furthermore, the ninth lens, L9, can be aspherical, which facilitates the correction of edge field-of-view distortion and better meets image quality requirements.

[0048] The sixth lens L6 and the seventh lens L7 can be cemented together to form a cemented lens, or the fifth lens L5, the sixth lens L6, and the seventh lens L7 can be cemented together to form a cemented lens.

[0049] Lenses L1, L5, L6, L7, and L8 can be spherical lenses, while lenses L2, L3, L4, and L6 can be aspherical lenses.

[0050] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, and the ninth lens L9 can all be glass lenses, without any plastic lenses, and have a long service life.

[0051] In a preferred embodiment of the present invention, the effective focal length f1 of the first lens L1 and the effective focal length f of the optical lens satisfy: -1.8 ≤ f1 / f ≤ -1.4. This setting can improve image quality, meet the requirements of ultra-wide-angle lenses, and ensure lens manufacturability.

[0052] In a preferred embodiment of the present invention, the effective focal length f2 of the second lens L2 and the effective focal length f of the optical lens satisfy: 3.0 ≤ f2 / f ≤ 10.6. This configuration, by rationally distributing the refractive power of the second lens L2, facilitates the smooth transmission of light, which is beneficial for correcting aberrations in the optical imaging system and improving the imaging quality of the optical imaging system.

[0053] In a preferred embodiment of the present invention, the effective focal length f3 of the third lens L3 and the effective focal length f of the optical lens satisfy: -2.2 ≤ f3 / f ≤ -1.2. This arrangement helps to widen the beam width, so that large-angle light rays can be fully transmitted to the rear optical system after passing through the third lens L3, thereby obtaining a wider field of view.

[0054] In a preferred embodiment of the present invention, the effective focal length f4 of the fourth lens L4 and the effective focal length f of the optical lens satisfy: 1.5 ≤ f4 / f ≤ 2.1. This arrangement allows light rays from different fields of view to diverge at a reasonable angle after being converged by the aperture stop STO, thereby converging at a more distant vertical axis position and increasing the imaging height of the optical lens.

[0055] In a preferred embodiment of the present invention, the effective focal length f5 of the fifth lens L5 and the effective focal length f of the optical lens satisfy: 2.0 ≤ f5 / f ≤ 2.6. This configuration effectively receives the beam from the front lens group, eliminating off-axis coma and astigmatism introduced by the compression of light by the front lens group.

[0056] In a preferred embodiment of the present invention, the effective focal length f6 of the sixth lens L6 and the effective focal length f of the optical lens satisfy: -1.3 ≤ f6 / f ≤ 2.2. Simultaneously, the effective focal length f7 of the seventh lens L7 and the effective focal length f of the optical lens satisfy: -3.7 ≤ f7 / f ≤ 2.1. This arrangement facilitates the correction of chromatic aberration generated by the first lens L1 to the fifth lens L5, and shares the correction burden of the image-side lens (i.e., the eighth lens L8), balancing the various levels of aberrations in the optical imaging system and improving the imaging quality of the optical imaging system. Furthermore, by limiting the effective focal length values ​​of the sixth lens L6 and the seventh lens L7, it is also beneficial to maintain imaging stability under high and low temperature conditions.

[0057] In a preferred embodiment of the present invention, the effective focal length f8 of the eighth lens L8 and the effective focal length f of the optical lens satisfy: -5.6 ≤ f8 / f ≤ -1.0. Simultaneously, the effective focal length f9 of the ninth lens L9 and the effective focal length f of the optical lens satisfy: 1.4 ≤ f9 / f ≤ 3.5. This arrangement allows for appropriate light divergence, which is beneficial for increasing the imaging area of ​​the lens, optimizing image quality, and improving the overall resolving power of the lens.

[0058] In a preferred embodiment of the present invention, the air gap C45 between the fourth lens L4 and the fifth lens L5 satisfies the condition 0.0 ≤ C45 / TTL ≤ 0.1 with respect to the total optical length TTL of the optical lens. This configuration, by rationally controlling the air gap between the fourth lens L4 and the fifth lens L5, facilitates a smoother light transition, improves product yield, and reduces production costs.

[0059] In a preferred embodiment of the present invention, the optical back focal length (BFL) of the optical lens and the total optical length (TTL) of the optical lens satisfy the following condition: 0.1 ≤ BFL / TTL ≤ 0.2. This configuration, through a reasonable back focal length setting, ensures the compatibility between the optical lens and the image sensor of the camera module, and also facilitates the compact assembly of the lens elements, enabling the optical lens to meet miniaturization design requirements and improving the assembly yield of the optical lens.

[0060] In a preferred embodiment of the present invention, the effective focal length f of the optical lens and the total optical length TTL of the optical lens satisfy: 7.8 ≤ TTL / f ≤ 8.9. This setting, through reasonable control of the ratio of the total optical length to the focal length, facilitates the miniaturization of the optical system.

[0061] In a preferred embodiment of the present invention, the combined focal length fa of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 satisfies the condition -3.5 ≤ fa / f ≤ 3.0 with the effective focal length f of the optical lens. This configuration allows the forward light rays to converge smoothly to near the optical axis, effectively correcting large-angle distortions. Simultaneously, it effectively reduces off-axis wide beam aberrations and field curvature, positively contributing to improved edge image quality.

[0062] In a preferred embodiment of the present invention, the combined focal length fb of the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, and the ninth lens L9 satisfies the condition that 2.1 ≤ fb / f ≤ 3.5 with respect to the effective focal length f of the lens. This arrangement can correct the field curvature generated by the lens group located in front of the aperture stop STO, reducing the impact of field curvature on resolving power.

[0063] In a preferred embodiment of the present invention, the maximum optical imaging height D of the optical lens and the effective focal length f of the optical lens satisfy the condition: 1.2 ≤ D / f ≤ 1.6. This configuration gives the optical lens the characteristic of a large target surface.

[0064] In a preferred embodiment of the present invention, the distance M1 from the object-side surface of the first lens L1 to the aperture stop STO satisfies the following condition with respect to the total optical length TTL of the optical lens: 0.3 ≤ M1 / TTL ≤ 0.6. This configuration reduces the length of the optical imaging system, which is beneficial for miniaturization and weight reduction.

[0065] In a preferred embodiment of the present invention, the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 satisfy: -0.6 ≤ f1 / f2 ≤ -0.1. This arrangement is beneficial for controlling the optical trajectory of the first two lenses (i.e., the first lens L1 and the second lens L2) of the optical lens, allowing large-angle field-of-view light rays to enter the optical lens and ensuring the wide-angle capability of the optical lens.

[0066] In a preferred embodiment of the present invention, the focal length f1 of the first lens L1 and the focal length f3 of the third lens L3 satisfy: 0.6 ≤ f1 / f3 ≤ 1.3. This configuration can effectively converge large-angle light rays, realize the wide-angle capability of the optical imaging system, and improve the imaging quality of the optical imaging system.

[0067] In a preferred embodiment of the present invention, the core thickness CT1 of the first lens L1 and the core thickness CT2 of the second lens L2 satisfy: 3.5 ≤ CT2 / CT1 ≤ 7.0. Here, the core thickness refers to the thickness of the lens along its optical axis. This configuration, by controlling the center thickness of the lens within a certain range, facilitates the processing and shaping of the lens, thereby reducing the difficulty of manufacturing.

[0068] In a preferred embodiment of the present invention, the core thickness CT8 of the eighth lens L8 and the core thickness CT9 of the ninth lens L9 satisfy: 3.2 ≤ CT9 / CT8 ≤ 7.9. This configuration effectively controls the spatial proportion of the rear lens group (eighth lens L8 and ninth lens L9) along the optical axis from the object-side surface of the first lens L1 to the image-side surface of the ninth lens L9, resulting in smoother light diffusion in the optical lens. This reduces the maximum principal ray incident angle, improves relative illumination, and enables the optical lens to achieve good image quality.

[0069] In summary, the wide-angle fixed-focus lens of this invention employs nine lenses. Through the combination of the optical power and shape of each lens, as well as reasonable parameter settings, it can achieve a large aperture (FNO≤1.8), a large field of view (FOV≥160°), and high resolution (35 million pixels). At the same time, it can also achieve at least one of the following beneficial effects: a large image plane (the imaging target surface can reach 1 / 1.8”), a small principal ray incident angle (CRA<18°), no blurring at high and low temperatures (-40~85°), good aberration correction, high color reproduction, long service life, and miniaturization.

[0070] The wide-angle fixed-focus lens of the present invention will be specifically described below with reference to four embodiments, accompanying drawings, and tables. In the following embodiments, the aperture stop STO is denoted as one side, and the image plane IM is denoted as another side.

[0071] The parameters for each embodiment that meets the above conditions are shown in Table 1 below:

[0072]

[0073]

[0074] Table 1

[0075] In various embodiments of the present invention, the aspherical lens of the wide-angle fixed-focus lens satisfies the following formula:

[0076]

[0077] In the above formula, z is the axial distance from the vertex to the surface at a position perpendicular to the optical axis at a height y; c represents the curvature at the vertex of the aspherical surface; k is the conic coefficient; A4, A6, A8, A 10 A 12 A 14 A 16 ...represent aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders, respectively.

[0078] Example 1

[0079] like Figure 1The image shown is a schematic diagram of the optical structure of a wide-angle fixed-focus lens according to Embodiment 1 of the present invention. In this embodiment:

[0080] The first lens L1 is a convex-concave lens with negative optical power.

[0081] The second lens L2 is a concave-convex lens with positive optical power.

[0082] The third lens L3 is a concave-convex lens with negative optical power.

[0083] The fourth lens, L4, is a convex-concave lens with positive optical power.

[0084] The fifth lens, L5, is a convex-convex lens with positive optical power.

[0085] The sixth lens, L6, is a convex-convex lens with positive optical power.

[0086] The seventh lens, L7, is a concave-convex lens with negative optical power.

[0087] The eighth lens, L8, is a concave-convex lens with negative optical power.

[0088] The ninth lens, L9, is a convex-convex lens with positive optical power.

[0089] The sixth lens L6 and the seventh lens L7 are cemented together.

[0090] In this embodiment, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the wide-angle fixed-focus lens are shown in Table 2:

[0091] Face number Surface type radius of curvature R Thickness d Refractive index Nd Abbe number Vd 1 spherical 11.46 0.47 2.0 28.3 2 spherical 3.14 2.86 3 aspherical -5.23 3.08 1.85 40.1 4 aspherical -4.25 0.33 5 aspherical -3.09 0.44 1.50 81.6 6 aspherical 5.74 0.02 7 aspherical 3.68 2.52 1.77 47.2 8 aspherical 34.94 0.31 STO spherical Infinity 0.42 10 spherical 4.54 1.96 1.50 81.6 11 spherical -9.40 0.05 12 spherical 7.32 2.24 1.50 81.6 13 spherical -3.55 0.61 1.81 25.5 14 spherical -8.75 0.53 15 spherical -3.96 0.53 1.77 29.7 16 spherical 9.95 0.21 17 aspherical 6.10 3.06 1.50 81.6 18 aspherical -3.33 0.73 19 spherical Infinity 0.50 1.52 64.2 20 spherical Infinity 1.84 IM spherical Infinity

[0092] Table 2

[0093] In this embodiment, the K-value and aspherical coefficient of the wide-angle fixed-focus lens are shown in Table 3:

[0094] Face number K value A4 A6 A8 A10 A12 A14 A16 3 1.36 3.93E-03 -3.39E-04 4.36E-05 -1.22E-06 -5.13E-10 1.55E-08 -3.62E-10 4 0.50 5.96E-03 -6.54E-04 1.44E-04 -1.16E-05 2.80E-07 2.32E-08 -4.10E-10 5 -0.96 3.93E-03 -7.45E-04 2.19E-04 -3.74E-05 2.47E-06 -4.32E-08 -1.98E-09 6 1.39 -1.00E-02 1.02E-03 -2.12E-04 1.43E-05 -3.07E-07 -6.31E-09 -4.96E-10 7 -0.06 -3.97E-03 2.17E-04 -3.26E-05 2.22E-06 -1.66E-07 1.02E-08 -1.08E-09 8 64.72 5.17E-03 9.68E-05 3.62E-05 7.07E-07 -7.79E-07 5.49E-08 -3.99E-09 17 -6.88 1.09E-03 4.16E-05 -7.89E-06 6.07E-07 -5.15E-09 -2.47E-09 0.00E+00 18 -0.34 5.48E-03 -7.64E-05 1.23E-05 -4.83E-08 5.96E-08 -4.54E-09 0.00E+00

[0095] Table 3

[0096] Combination Figure 1 As shown in Tables 1-3 above, this embodiment uses nine lenses. By matching the optical power and shape of each lens and setting reasonable parameters, it can achieve a large aperture (FNO≤1.8), a large field of view (FOV≥160°), and high resolution (35 million pixels). At the same time, it can also take into account at least one of the following beneficial effects: large image plane (the imaging target surface can reach 1 / 1.8”), small principal ray incident angle (CRA<18°), no blurring at high and low temperatures (-40~85°), good aberration correction, high color reproduction, long service life, and miniaturization.

[0097] Example 2

[0098] like Figure 2 The diagram shown is a schematic representation of the optical structure of a wide-angle fixed-focus lens according to Embodiment 2 of the present invention.

[0099] In this embodiment:

[0100] The first lens L1 is a convex-concave lens with negative optical power.

[0101] The second lens L2 is a concave-convex lens with positive optical power.

[0102] The third lens L3 is a concave-convex lens with negative optical power.

[0103] The fourth lens, L4, is a convex-concave lens with positive optical power.

[0104] The fifth lens, L5, is a convex-convex lens with positive optical power.

[0105] The sixth lens, L6, is a convex-convex lens with positive optical power.

[0106] The seventh lens, L7, is a concave-convex lens with negative optical power.

[0107] The eighth lens, L8, is a concave-convex lens with negative optical power.

[0108] The ninth lens, L9, is a convex-convex lens with positive optical power.

[0109] The sixth lens L6 and the seventh lens L7 are cemented together.

[0110] In this embodiment, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the wide-angle fixed-focus lens are shown in Table 4:

[0111]

[0112]

[0113] Table 4

[0114] In this embodiment, the K-value and aspherical coefficient of the wide-angle fixed-focus lens are shown in Table 5:

[0115] Face number K value A4 A6 A8 A10 A12 A14 A16 3 1.26 4.26E-03 -3.60E-04 4.15E-05 -1.27E-06 -1.79E-08 1.06E-08 -5.52E-10 4 0.55 5.66E-03 -6.78E-04 1.43E-04 -1.16E-05 2.72E-07 2.12E-08 -5.34E-10 5 -0.99 4.03E-03 -7.59E-04 2.19E-04 -3.73E-05 2.51E-06 -3.77E-08 -1.91E-09 6 1.39 -1.01E-02 1.01E-03 -2.13E-04 1.45E-05 -2.73E-07 -3.02E-09 -3.68E-10 7 -0.04 -3.96E-03 2.51E-04 -2.92E-05 2.17E-06 -2.03E-07 8.99E-09 -2.82E-10 8 129.48 5.50E-03 1.08E-04 3.86E-05 1.16E-06 -7.22E-07 5.22E-08 -4.93E-09 17 -7.00 9.83E-04 3.45E-05 -7.03E-06 6.43E-07 -1.70E-08 -2.41E-09 0.00E+00 18 -0.34 5.60E-03 -5.97E-05 1.27E-05 -5.05E-08 6.15E-08 -4.88E-09 0.00E+00

[0116] Table 5

[0117] Combination Figure 2As shown in Tables 1 and 4-5 above, this embodiment uses nine lenses. By matching the optical power and shape of each lens and setting reasonable parameters, it can achieve a large aperture (FNO≤1.8), a large field of view (FOV≥160°), and high resolution (35 million pixels). At the same time, it can also take into account at least one of the following beneficial effects: large image plane (the imaging target surface can reach 1 / 1.8”), small principal ray incident angle (CRA<18°), no blurring at high and low temperatures (-40~85°), good aberration correction, high color reproduction, long service life, and miniaturization.

[0118] Example 3

[0119] like Figure 3 The image shown is a schematic diagram of the optical structure of a wide-angle fixed-focus lens according to Embodiment 3 of the present invention. In this embodiment:

[0120] The first lens L1 is a convex-concave lens with negative optical power.

[0121] The second lens L2 is a concave-convex lens with positive optical power.

[0122] The third lens L3 is a concave-convex lens with negative optical power.

[0123] The fourth lens, L4, is a convex-concave lens with positive optical power.

[0124] The fifth lens, L5, is a convex-convex lens with positive optical power.

[0125] The sixth lens, L6, is a convex-convex lens with positive optical power.

[0126] The seventh lens, L7, is a concave-convex lens with negative optical power.

[0127] The eighth lens, L8, is a concave-convex lens with negative optical power.

[0128] The ninth lens, L9, is a convex-convex lens with positive optical power.

[0129] The sixth lens L6 and the seventh lens L7 are cemented together.

[0130] In this embodiment, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the wide-angle fixed-focus lens are shown in Table 6:

[0131] Face number Surface type radius of curvature R Thickness d Refractive index Nd Abbe number Vd 1 spherical 10.10 0.50 2.0 28.3 2 spherical 3.01 2.90 3 aspherical -5.01 1.85 1.95 29.8 4 aspherical -4.99 0.46 5 aspherical -3.51 0.50 1.55 71.7 6 aspherical 6.90 0.05 7 aspherical 4.38 4.02 1.88 37.2 8 aspherical 100.00 0.17 STO spherical Infinity 0.05 10 spherical 5.25 2.21 1.50 81.6 11 spherical -7.41 0.05 12 spherical 5.78 2.62 1.50 81.6 13 spherical -3.50 0.50 1.81 25.5 14 spherical -25.13 0.59 15 spherical -5.82 0.50 1.63 35.7 16 spherical 9.56 0.05 17 aspherical 5.93 2.92 1.50 81.6 18 aspherical -3.66 0.64 19 spherical Infinity 0.50 1.52 64.2 20 spherical Infinity 1.91 IM spherical Infinity

[0132] Table 6

[0133] In this embodiment, the K-value and aspherical coefficient of the wide-angle fixed-focus lens are shown in Table 7:

[0134]

[0135]

[0136] Table 7

[0137] Combination Figure 3 As shown in Tables 1 and 6-7 above, this embodiment uses nine lenses. By matching the optical power and shape of each lens and setting reasonable parameters, it can achieve a large aperture (FNO≤1.8), a large field of view (FOV≥160°), and high resolution (35 million pixels). At the same time, it can also take into account at least one of the following beneficial effects: large image plane (the imaging target surface can reach 1 / 1.8”), small principal ray incident angle (CRA<18°), no blurring at high and low temperatures (-40~85°), good aberration correction, high color reproduction, long service life, and miniaturization.

[0138] Example 4

[0139] like Figure 4 The diagram shown is a schematic representation of the optical structure of a wide-angle fixed-focus lens according to Embodiment 4 of the present invention.

[0140] In this embodiment:

[0141] The first lens L1 is a convex-concave lens with negative optical power.

[0142] The second lens L2 is a concave-convex lens with positive optical power.

[0143] The third lens L3 is a concave-convex lens with negative optical power.

[0144] The fourth lens, L4, is a convex-convex lens with positive optical power.

[0145] The fifth lens, L5, is a convex-convex lens with positive optical power.

[0146] The sixth lens, L6, is a concave-convex lens with negative optical power.

[0147] The seventh lens, L7, is a convex-convex lens with positive optical power.

[0148] The eighth lens, L8, is a concave-convex lens with negative optical power.

[0149] The ninth lens, L9, is a convex-convex lens with positive optical power.

[0150] The fifth lens L5, the sixth lens L6, and the seventh lens L7 are cemented together.

[0151] In this embodiment, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the wide-angle fixed-focus lens are shown in Table 8:

[0152]

[0153]

[0154] Table 8

[0155] In this embodiment, the K-value and aspherical coefficient of the wide-angle fixed-focus lens are shown in Table 9:

[0156] Face number K value A4 A6 A8 A10 A12 A14 A16 3 2.01 3.88E-03 -1.82E-04 5.34E-05 -1.00E-05 1.84E-06 -1.43E-07 5.87E-09 4 0.02 6.28E-03 -6.36E-04 9.65E-05 -5.69E-06 -1.78E-07 6.57E-08 -2.92E-09 5 -0.80 2.87E-03 -7.85E-04 3.13E-04 -5.24E-05 4.80E-06 -1.67E-07 -2.46E-09 6 -0.19 -1.21E-02 1.90E-03 -2.53E-04 1.75E-05 -5.98E-07 3.22E-08 -4.05E-09 7 0.22 -1.61E-03 3.13E-04 -4.19E-05 2.53E-06 -3.91E-07 8.63E-08 -6.40E-09 8 18.53 5.53E-03 2.59E-04 1.14E-05 -1.01E-05 2.93E-06 -5.04E-08 -4.37E-08 15 -15.91 1.97E-03 8.77E-05 -1.20E-05 9.21E-07 -4.58E-08 4.93E-10 0.00E+00 16 5.93 3.10E-03 1.34E-04 -1.33E-05 1.81E-06 -1.46E-07 3.42E-09 0.00E+00

[0157] Table 9

[0158] Combination Figure 4 As shown in Tables 1 and 8-9 above, this embodiment uses nine lenses. By matching the optical power and shape of each lens and setting reasonable parameters, it can achieve a large aperture (FNO≤1.8), a large field of view (FOV≥160°), and high resolution (35 million pixels). At the same time, it can also take into account at least one of the following beneficial effects: large image plane (the imaging target surface can reach 1 / 1.8”), small principal ray incident angle (CRA<18°), no blurring at high and low temperatures (-40~85°), good aberration correction, high color reproduction, long service life, and miniaturization.

[0159] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wide-angle fixed-focus lens, comprising, in sequence along the optical axis from the object side to the image side, 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), totaling nine lenses with optical power, characterized in that, The first lens (L1), the third lens (L3), and the eighth lens (L8) have negative optical power, the second lens (L2), the fourth lens (L4), the fifth lens (L5), and the ninth lens (L9) have positive optical power, and the sixth lens (L6) and the seventh lens (L7) have opposite optical powers. The focal length f1 of the first lens (L1) and the focal length f3 of the third lens (L3) satisfy: 0.6≤f1 / f3≤1.

3.

2. The wide-angle fixed-focus lens according to claim 1, characterized in that, The first lens (L1) is a convex-concave lens, the second lens (L2) is a concave-convex lens, the third lens (L3) and the eighth lens (L8) are concave-concave lenses, the fourth lens (L4) is a lens with a convex object side, the fifth lens (L5) and the ninth lens (L9) are convex-convex lenses, the seventh lens (L7) is a lens with a convex image side, and the sixth lens (L6) is a convex-convex lens or a concave-concave lens.

3. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f1 of the first lens (L1) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: -1.8≤f1 / f≤-1.

4.

4. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f2 of the second lens (L2) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: 3.0≤f2 / f≤10.

6.

5. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f3 of the third lens (L3) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: -2.2≤f3 / f≤-1.

2.

6. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f4 of the fourth lens (L4) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: 1.5≤f4 / f≤2.

1.

7. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f5 of the fifth lens (L5) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: 2.0≤f5 / f≤2.

6.

8. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f6 of the sixth lens (L6) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: -1.3≤f6 / f≤2.

2.

9. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f7 of the seventh lens (L7) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: -3.7≤f7 / f≤2.

1.

10. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f8 of the eighth lens (L8) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: -5.6≤f8 / f≤-1.

0.

11. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f9 of the ninth lens (L9) and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: 1.4≤f9 / f≤3.

5.

12. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The air gap C45 between the fourth lens (L4) and the fifth lens (L5) satisfies the following condition: 0.0≤C45 / TTL≤0.

1.

13. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The optical back focal length (BFL) of the wide-angle fixed-focus lens and the optical total length (TTL) of the wide-angle fixed-focus lens satisfy the following: 0.1≤BFL / TTL≤0.

2.

14. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The effective focal length f and the total optical length TTL of the wide-angle fixed-focus lens satisfy the following: 7.8≤TTL / f≤8.

9.

15. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The combined focal length fa of the first lens (L1), the second lens (L2), the third lens (L3), and the fourth lens (L4) satisfies the following condition: -3.5≤fa / f≤3.

0.

16. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The combined focal length fb of the fifth lens (L5), the sixth lens (L6), the seventh lens (L7), the eighth lens (L8), and the ninth lens (L9) satisfies the following condition: 2.1≤fb / f≤3.

5.

17. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The maximum imaging height D of the wide-angle fixed-focus lens and the effective focal length f of the wide-angle fixed-focus lens satisfy the following: 1.2≤D / f≤1.

6.

18. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The distance M1 from the object-side surface of the first lens (L1) to the aperture stop satisfies the following condition: 0.3≤M1 / TTL≤0.

6.

19. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The core thickness CT1 of the first lens (L1) and the core thickness CT2 of the second lens (L2) satisfy the following: 3.5≤CT2 / CT1≤7.

0.

20. The wide-angle fixed-focus lens according to claim 1 or 2, characterized in that, The core thickness CT8 of the eighth lens (L8) and the core thickness CT9 of the ninth lens (L9) satisfy the following: 3.2≤CT9 / CT8≤7.9.

Images