A fisheye lens system

Abstract

The application discloses a fisheye lens system, which comprises, in sequence from an object side to an imaging surface along an optical axis, a first lens L1 with negative optical power and a spherical surface, a second lens L2 with negative optical power and a non-spherical surface, a third lens L3 with positive optical power and a spherical surface, a stop STO, a fourth lens L4 with positive optical power and a spherical surface, wherein the object side surface of the fourth lens L4 is a convex surface, and the image side surface of the fourth lens L4 is a concave surface, a fifth lens L5 with negative optical power and a spherical surface, wherein the object side surface and the image side surface of the fifth lens L5 are both convex surfaces, a sixth lens L6 with negative optical power and a non-spherical surface, wherein the object side surface of the sixth lens L6 is a plane, and the image side surface of the sixth lens L6 is a concave surface, a seventh lens L7 with positive optical power and a non-spherical surface, wherein the object side surface and the image side surface of the seventh lens L7 are both convex surfaces, and TTL is less than or equal to 35.0 mm, wherein TTL is the distance between the object side surface of the first lens L1 and the imaging surface.

Description

Technical Field

[0001] This invention relates to the field of lens technology, and in particular to a fisheye lens system. Background Technology

[0002] With rising living standards and increased security awareness, consumers are demanding higher standards from security monitoring lenses, expecting them to possess advantages such as ultra-wide field of view, high resolution, and adaptability to both day and night conditions. Fisheye lenses, due to their ultra-wide field of view, are widely used in security, automotive, and smart home applications. However, this very wide field of view introduces significant barrel distortion, greatly compressing image quality at the lens edges, resulting in reduced edge resolution, blurred image quality, and a larger overall size. Summary of the Invention

[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a fisheye lens system with small size, high pixel count, and low distortion.

[0004] According to an embodiment of the fisheye lens system of the present invention, the system comprises, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1 having negative optical power and a spherical surface, wherein the object side of the first lens L1 is convex and the image side is concave; a second lens L2 having negative optical power and an aspherical surface, wherein the object side of the second lens L2 is convex and the image side is concave; a third lens L3 having positive optical power and a spherical surface, wherein the object side of the third lens L3 is concave and the image side is convex; an aperture stop STO; and a fourth lens having positive optical power and a spherical surface. L4, the fourth lens L4 has a convex object-side surface and a concave image-side surface; L5, the fifth lens L5 has negative optical power and is spherical, with both its object-side and image-side surfaces being convex; L6, the sixth lens L6 has negative optical power and is aspherical, with its object-side surface being planar and its image-side surface being concave; L7, the seventh lens L7 has positive optical power and is aspherical, with both its object-side and image-side surfaces being convex; TTL ≤ 35.0 mm, where TTL is the distance between the object-side surface of the first lens L1 and the imaging plane.

[0005] According to the fisheye lens system of the present invention, the following condition is satisfied: 0.11≤BFL / TTL≤0.29, where BFL is the distance from the center of the optical axis on the image side of the seventh lens L7 to the imaging plane. The total length of the lens is controlled within 35.0mm, the structure is more compact, and by controlling BFL, various aberrations are corrected, edge image quality is improved, and the imaging quality is high.

[0006] The fisheye lens system according to an embodiment of the present invention satisfies the following conditional expression: 1.8 ≤ F ≤ 2.4, where F is the aperture value, and the lens can form clear images even under low-light conditions.

[0007] The fisheye lens system according to an embodiment of the present invention satisfies the following conditional expression: 7.07 mm ≤ IC, wherein IC is the image plane diameter of the fisheye lens system.

[0008] The fisheye lens system according to an embodiment of the present invention satisfies the following conditional expression: TTL / EFL ≤ 19.5, wherein EFL is the effective focal length of the fisheye lens system. By adopting a combination of different lenses and reasonably distributing optical power, the system has good performances such as day-night common focus, large field of view, high pixels, and excellent athermalization performance.

[0009] The fisheye lens system according to an embodiment of the present invention satisfies the following conditional expression: 1.0 < |f(1+2) / f| < 2.4, wherein f(1+2) is the combined focal length of the first lens L1 and the second lens L2, and f is the focal length of the fisheye lens system. When the value of |f(1+2) / f| is small, the total optical length TTL is easier to control; when the value of |f(1+2) / f| is large, aberration is easier to control.

[0010] The fisheye lens system according to an embodiment of the present invention satisfies the following conditional expressions: –14.2 < f1 < -12.2; -9.2 < f2 < -7.5; 26.0 < f3 < 29.5; 7.0 < f4 < 9.0; -75.0 < f5 < -71.0; -8.5 < f6 < -7.0; 4.5 < f7 < 5.8; wherein 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, and f7 is the focal length of the seventh lens L7.

[0011] The fisheye lens system according to an embodiment of the present invention satisfies the following conditional expressions:

[0012] 1.72 ≤ n1 ≤ 1.84; 44.5 ≤ v1 ≤ 48.0;

[0013] 1.53 ≤ n2 ≤ 1.56; 50.0 ≤ v2 ≤ 60.0;

[0014] 1.86 ≤ n3 ≤ 1.95; 17.5 ≤ v3 ≤ 19.2;

[0015] 1.75 ≤ n4 ≤ 1.85; 24.5 ≤ v4 ≤ 26.5;

[0016] 1.58 ≤ n5 ≤ 1.63; 60.0 ≤ v5 ≤ 65.0;

[0017] 1.60≤n6≤1.68; 22.0≤v6≤24.0;

[0018] 1.50≤n7≤1.55; 50.0≤v7≤60.0;

[0019] Where n1 to n7 are the refractive indices of the first lens L1 to the seventh lens L7, and v1 to v7 are the dispersion coefficients of the first lens L1 to the seventh lens L7.

[0020] According to an embodiment of the present invention, the fisheye lens system includes at least one glass lens and one plastic lens. The plastic aspherical lens has lower cost and lighter weight than the glass spherical lens. By comprehensively setting the optical power and shape matching relationship of each lens, low cost and lightweight can be achieved.

[0021] The fisheye lens system according to an embodiment of the present invention further includes a protective glass located between the seventh lens L7 and the imaging plane.

[0022] The fisheye lens system according to embodiments of the present invention has at least the following beneficial effects: the object plane of the first lens L1 is convex and the image plane is concave, which is beneficial for the collection of light by the optical system and the correction of astigmatism of the fisheye optical system; by setting a second lens L2 with negative optical power, the lens angle of view is wider; and by making both the first lens L1 and the second lens L2 have negative optical power, unreasonable shape of the first lens L1 can be effectively prevented, improving manufacturability and reasonable control of distortion; by setting a third lens L3 with positive optical power, the propagation direction of the light path is changed; by setting a fourth lens L4 with a concave-convex shape, the residual aberration of the first few lenses is corrected, which plays a role in correcting field curvature; at the same time, the bonding state of the fourth lens L4 and the fifth lens L5 is reasonably controlled so that the bonding lens has positive optical power; thus, setting several lenses with positive optical power from the aperture stop STO to the imaging plane can make the light refract towards the imaging plane faster, which is beneficial to reducing the overall length of the optical system and can achieve low cost and lightweight. This lens effectively controls the direction of light, allowing for greater light intake while maintaining a more compact structure. The total length of the lens is kept within 35.0mm, and various aberrations are corrected through the proper arrangement of aspherical lenses, improving edge image quality and resulting in high overall image quality.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings;

[0025] Figure 1This is a lens distribution diagram of a fisheye lens system;

[0026] Figure 2 This is the visible light MTF curve of a fisheye lens system;

[0027] Figure 3 This is the infrared MTF curve of the fisheye lens system;

[0028] Figure 4 This is the Through-Focus-MTF curve of the fisheye lens system at 20℃;

[0029] Figure 5 This is the -40℃ Through-Focus-MTF curve of the fisheye lens system;

[0030] Figure 6 This is the Through-Focus-MTF curve of the fisheye lens system at 80°C;

[0031] Figure 7 This is a spherical aberration curve of a fisheye lens system;

[0032] Figure 8 It is the lateral fan pattern of the fisheye lens system;

[0033] Figure 9 This is the F-Tan distortion curve of the fisheye lens system. Detailed Implementation

[0034] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0036] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0037] Reference Figures 1 to 9 This invention discloses a fisheye lens system, comprising, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1 with negative optical power and a spherical surface, wherein the object side of the first lens L1 is convex and the image side is concave; a second lens L2 with negative optical power and an aspherical surface, wherein the object side of the second lens L2 is convex and the image side is concave; a third lens L3 with positive optical power and a spherical surface, wherein the object side of the third lens L3 is concave and the image side is convex; an aperture stop STO; and a third lens L3 with positive optical power and an aspherical surface. The system comprises: a fourth lens L4 with a convex object-side surface and a concave image-side surface; a fifth lens L5 with negative optical power and a spherical surface, both its object-side and image-side surfaces being convex; a sixth lens L6 with negative optical power and an aspherical surface, its object-side surface being planar and its image-side surface being concave; and a seventh lens L7 with positive optical power and an aspherical surface, both its object-side and image-side surfaces being convex. The total length (TTL) of the fisheye lens system is ≤35.0 mm. The first lens L1 has a convex object plane and a concave image plane, which is beneficial for light collection and correction of astigmatism in the optical system. The second lens L2, with its negative optical power, provides a wider field of view. Furthermore, by ensuring both the first and second lenses have negative optical power, the unreasonable shape of the first lens L1 is effectively prevented, improving manufacturability and distortion control. The third lens L3, with its positive optical power, alters the direction of light propagation. The fourth lens L4, with its concave-convex shape, corrects residual aberrations in the previous lenses, thus correcting field curvature. Simultaneously, by controlling the bonding state of the fourth lens L4 and the fifth lens L5, the bonded lens exhibits positive optical power. Therefore, placing several positive optical power lenses between the aperture stop STO and the image plane allows light to refract towards the image plane more quickly, reducing the overall length of the optical system and achieving low cost and lightweight design. This lens effectively controls the direction of light, allowing for greater light intake while maintaining a more compact structure. The total length of the lens is kept within 35.0mm, and various aberrations are corrected through the proper arrangement of aspherical lenses, improving edge image quality and resulting in high overall image quality.

[0038] In some embodiments, the fisheye lens satisfies the following condition: 0.11≤BFL / TTL≤0.29, where BFL is the distance from the center of the optical axis on the image side of the seventh lens L7 to the imaging plane. The total length of the lens is controlled within 35.0mm, making the structure more compact. By controlling BFL, various aberrations are corrected, improving edge image quality and resulting in high image quality.

[0039] In some embodiments, the fisheye lens satisfies the following conditional expression: 1.8≤F≤2.4, wherein F is an aperture value, and the lens can form clear images even in low light conditions.

[0040] In some embodiments, the fisheye lens satisfies the following conditional expression: 7.07mm≤IC, wherein IC is the image plane diameter of the fisheye lens system.

[0041] In some embodiments, the fisheye lens satisfies the following conditional expression: TTL / EFL≤19.5, wherein EFL is the effective focal length of the fisheye lens. By adopting mutual combination of different lenses and reasonable distribution of optical power, the fisheye lens has good performances such as day-night common focusing, large viewing angle, high pixels and excellent athermalization.

[0042] In some embodiments, the fisheye lens satisfies the following conditional expression: 1.0<|f(1+2) / f|<2.4, wherein f(1+2) is the combined focal length of the first lens L1 and the second lens L2, and f is the focal length of the fisheye lens. When the value of |f(1+2) / f| is small, the total optical length TTL is well controlled, and when the value of |f(1+2) / f| is large, the aberration is well controlled.

[0043] In some embodiments, the fisheye lens satisfies the following conditional expressions: –14.2<f1<-12.2; -9.2<f2<-7.5; 26.0<f3<29.5; 7.0<f4<9.0; -75.0<f5<-71.0; -8.5<f6<-7.0; 4.5<f7<5.8; wherein 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, and f7 is the focal length of the seventh lens L7.

[0044] In some embodiments, the fisheye lens satisfies the following conditional expressions:

[0045] 1.72≤n1≤1.84; 44.5≤v1≤48.0;

[0046] 1.53≤n2≤1.56; 50.0≤v2≤60.0;

[0047] 1.86≤n3≤1.95; 17.5≤v3≤19.2;

[0048] 1.75≤n4≤1.85; 24.5≤v4≤26.5;

[0049] 1.58≤n5≤1.63; 60.0≤v5≤65.0;

[0050] 1.60≤n6≤1.68; 22.0≤v6≤24.0;

[0051] 1.50≤n7≤1.55; 50.0≤v7≤60.0;

[0052] Where n1 to n7 are the refractive indices of the first lens L1 to the seventh lens L7, and v1 to v7 are the dispersion coefficients of the first lens L1 to the seventh lens L7.

[0053] In some embodiments, the fisheye lens includes at least one glass lens and one plastic lens; the plastic aspherical lens has lower cost and lighter weight than the glass spherical lens, and low cost and lightweight can be achieved by comprehensively setting the optical power and shape matching relationship of each lens.

[0054] According to an embodiment of the fisheye lens system of the present invention, a photosensitive chip IMAGE is provided on the image side of the seventh lens L7, and a protective glass CG is provided between the seventh lens L7 and the IMAGE. The protective glass CG can effectively protect the photosensitive chip IMAGE, and the protective glass CG can also be a filter, which can not only protect the photosensitive chip IMAGE, but also filter out stray light, further improving the image quality. In some embodiments, the filter is a planar filter, which includes a first filter and a second filter. The first filter and the second filter can be switched through an existing specific mechanical structure. In daytime, infrared light is filtered out by the first filter and visible light is allowed to pass through, realizing daytime shooting function; in nighttime, both visible light and infrared light can pass through the second filter, realizing nighttime shooting function.

[0055] In various embodiments of the present invention, each aspherical surface shape satisfies the following equation:

[0056]

[0057] Where z represents the axial sagitta in the Z direction of the aspherical surface; y represents the height of the aspherical surface; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the conic coefficient; and the 4th, 6th, 8th, 10th, 12th, and 14th order terms represent higher-order aspherical coefficients, respectively. Specific implementation examples:

[0059] The fisheye lens in this embodiment has a focal length of f = 1.76 mm, an aperture of F = 1.8, an image plane diameter of 7.07 mm, and a horizontal angle of ≥185°.

[0060] Please see Figure 1The diagram shows a schematic of the fisheye lens system provided in Embodiment 1 of the present invention. The fisheye lens includes, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a protective glass CG. The optical centers of each lens are located on the same straight line. The first lens L1 is a glass spherical surface, the second lens L2 is a plastic aspherical surface, the third lens L3 is a glass spherical surface, the fourth lens L4 is a glass spherical surface, the fifth lens L5 is a glass spherical surface, the sixth lens L6 is a plastic aspherical surface, and the seventh lens L7 is a plastic aspherical surface.

[0061] The relevant parameters of each lens in the fisheye lens system provided in this embodiment are shown in Table 1-1.

[0062] Table 1-1

[0063]

[0064] The relevant parameters of the aspherical lens of the fisheye lens in this embodiment are shown in Table 1-2.

[0065] Table 1-2

[0066] L2 object side 33.936 4.17E-03 -1.19E-04 1.29E-06 -4.84E-09 4.21E-11 L2 image side view -0.496 4.68E-03 4.38E-04 -3.98E-05 7.67E-07 7.44E-09 L5 side view 20.282 -1.20E-02 8.01E-04 -5.15E-05 -1.81E-06 -4.31E-09 L6 object side -0.164 -1.93E-02 1.57E-03 -1.43E-04 3.41E-06 1.32E-09 L6 side view -0.725 -5.26E-03 4.30E-04 -1.48E-05 4.11E-07 -6.46E-05 L7 side view -1.748 1.74E-03 6.73E-05 1.01E-05 7.16E-07 -5.56E-06

[0067] In this embodiment, the visible light MTF curve, infrared MTF curve, through-focus-MTF curves at 20℃, -40℃, and 80℃, spherical aberration curve, lateral fan pattern, and F-Tan field distortion curve of the fisheye lens system are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 As shown.

[0068] Please see Figure 2 The figure shows the visible light diffraction MTF curve of the fisheye lens in this embodiment. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the OTF coefficient. As can be seen from the figure, the OTF is above 0.3 at a spatial frequency of 200 p / mm, indicating that the fisheye lens has high resolution.

[0069] Please see Figure 3 The figure shows the MTF curve of the infrared light of the fisheye lens in this embodiment. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the OTF coefficient. It can be seen from the figure that the OTF is above 0.4 at a spatial frequency of 200p / mm, indicating that the fisheye lens has a high resolution.

[0070] Please see Figure 4 The figure shows the Through-Focus-MTF curve of the fisheye lens in this embodiment at 20°C. The horizontal axis represents the focus shift distance (unit: mm), and the vertical axis represents the OTF coefficient. As can be seen from the figure, the overall waveform is centered at a spatial frequency of 1251p / mm, indicating that the fisheye lens has good performance.

[0071] Please see Figure 5 The figure shows the Through-Focus-MTF curve of the fisheye lens in this embodiment at -40℃. The horizontal axis represents the focal shift distance (unit: mm), and the vertical axis represents the OTF coefficient. It can be seen from the figure that at a spatial frequency of 1251p / mm, the overall waveform shifts to the right by less than 0.008mm, indicating that the fisheye lens has high resolution and low distortion rate at low temperature.

[0072] Please see Figure 6 The figure shows the Through-Focus-MTF curve of the fisheye lens at 80℃ in this embodiment. The horizontal axis represents the focal shift distance (unit: mm), and the vertical axis represents the OTF coefficient. As can be seen from the figure, at a spatial frequency of 1251p / mm, the overall waveform shifts to the left by less than 0.003mm, indicating that the fisheye lens has high resolution and low distortion rate at high temperatures.

[0073] Please see Figure 7 The figure shows a schematic diagram of the spherical aberration curve of the fisheye lens in this embodiment. The horizontal axis represents the axial aberration (unit: mm), and the vertical axis represents the pupil radius. As can be seen from the figure, when the pupil radius is 0.4886 mm, the aberration offset is controlled within ±0.01 mm, indicating that the fisheye lens can effectively correct on-axis spherical aberration.

[0074] Please see Figure 8 The figure shows the lateral optical fan pattern of the fisheye lens in this embodiment. As can be seen from the figure, the maximum scaling ratio is ±20um.

[0075] Please see Figure 9 The figure shows the F-Tan distortion curve of the fisheye lens in this embodiment. As can be seen from the figure, the overall distortion is controlled within 23%, which indicates that the fisheye lens has well controlled the system distortion during the design stage.

[0076] It will be readily understood by those skilled in the art that the above preferred methods can be freely combined and superimposed without conflict.

[0077] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made based on the inventive concept of the present invention and the description and drawings, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention. It will be readily understood by those skilled in the art that the above preferred embodiments can be freely combined and superimposed without conflict.

Claims

1. A fisheye lens system, characterized in that, Along the optical axis from the object side to the imaging plane, the following are included in sequence: A first lens L1 with negative optical power and a spherical surface, wherein the object side of the first lens L1 is convex and the image side of the first lens L1 is concave. A second lens L2 with negative optical power and an aspherical surface, wherein the object side of the second lens L2 is convex and the image side is concave; A third lens L3 with positive optical power and a spherical surface, wherein the object side of the third lens L3 is concave and the image side is convex. Aperture STO; A fourth lens L4 with positive optical power and a spherical surface, wherein the object side of the fourth lens L4 is convex and the image side is concave. A fifth lens L5 with negative optical power and a spherical surface, wherein both the object-side surface and the image-side surface of the fifth lens L5 are convex. A sixth lens L6 with negative optical power and an aspherical surface, wherein the object side of the sixth lens L6 is a plane and the image side is a concave surface; A seventh lens L7 with positive optical power and an aspherical surface, wherein both the object-side surface and the image-side surface of the seventh lens L7 are convex. TTL≤35.0mm, where TTL is the distance between the object surface of the first lens L1 and the imaging surface; The following condition must be met: –14.2 <f1<-12.2;-9.2<f2<-7.5;26.0<f3<29.5;7.0<f4<9.0;-75.0<f5<-71.0;-8.5<f6<-7.0;4.5<f7<5.8; Where 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, and f7 is the focal length of the seventh lens L7. It has seven lenses: the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7.

2. The fisheye lens system according to claim 1, characterized in that, The following condition must be met: 0.10≤BFL / TTL≤0.25, where BFL is the distance from the center of the optical axis on the image side of the seventh lens L7 to the imaging plane.

3. The fisheye lens system according to claim 1, characterized in that, The following condition must be met: 1.8≤F≤2.4, where F is the aperture value.

4. The fisheye lens system according to claim 1, characterized in that, The following condition must be met: 7.07mm≤IC, where IC is the image plane diameter of the fisheye lens system.

5. The fisheye lens system according to claim 1, characterized in that, The following condition must be met: TTL / EFL≤19.5, where EFL is the effective focal length of the fisheye lens system.

6. The fisheye lens system according to claim 1, characterized in that, The following condition must be met: 1.0 < |f(1+2) / f| < 2.4, where f(1+2) is the focal length of the combination of the first lens L1 and the second lens L2, and f is the focal length of the fisheye lens system.

7. The fisheye lens system according to claim 1, characterized in that, The following conditions must be met: 1.72≤n1≤1.84; 44.5≤v1≤48.0; 1.53≤n²≤1.56; 50.0≤v²≤60.0; 1.86≤n3≤1.95; 17.5≤v3≤19.2; 1.75≤n4≤1.85; 24.5≤v4≤26.5; 1.58≤n5≤1.63; 60.0≤v5≤65.0; 1.60≤n6≤1.68; 22.0≤v6≤24.0; 1.50≤n7≤1.55; 50.0≤v7≤60.0; Where n1 to n7 are the refractive indices of the first lens L1 to the seventh lens L7, and v1 to v7 are the dispersion coefficients of the first lens L1 to the seventh lens L7.

8. The fisheye lens system according to claim 1, characterized in that: It includes at least one glass lens and one plastic lens.

9. The fisheye lens system according to claim 1, characterized in that: It also includes a protective glass, which is located between the seventh lens L7 and the imaging surface.

Images