fisheye lens

Abstract

The application relates to a fisheye lens which comprises, in sequence from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens; the first lens is a convex-concave lens with negative focal power; the second lens is a lens with negative focal power and a concave image side surface; the third lens is a convex-concave lens with positive focal power; the fourth lens is a concave-convex lens with positive focal power; the fifth lens is a convex-convex lens with positive focal power; the sixth lens is a concave-convex lens with negative focal power; the effective focal length F5 of the fifth lens, the effective focal length F6 of the sixth lens and the total effective focal length F of the fisheye lens satisfy the following relationship: -2.23 <= F5*F6 / F <= -1.73. The application can simultaneously consider a large field angle, high imaging quality, low distortion, a large aperture and simultaneously meet small size and low cost.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically to a fisheye lens. Background Technology

[0002] With the continuous advancement of existing image processing algorithms and AI technology, the applications of fisheye lenses have become more diversified in recent years, and they are widely used in various fields such as action cameras, drones, smart doorbells and smart homes. As a result, the requirements for fisheye lenses are also getting higher and higher.

[0003] However, existing fisheye lenses still have at least the following shortcomings: 1. Existing fisheye lenses have a small field of view, making them unsuitable for environments with a wide field of view; 2. Existing fisheye lens lens configurations are difficult to effectively correct system aberrations, resulting in poor image quality; 3. Existing fisheye lenses suffer from excessive overall lens length, too many lens elements, and large size, leading to high overall cost and weight; 4. Existing fisheye lenses have relatively small apertures and poor light transmission performance, making them unsuitable for dark environments such as nighttime or rainy days; 5. Existing fisheye lenses have poor lens distortion control, resulting in noticeable distortion in the captured images, affecting post-processing.

[0004] In summary, there is an urgent need for a fisheye lens that has a wide field of view, high image quality, low distortion, large aperture, and is also small in size and low in cost. Summary of the Invention

[0005] In view of this, the present invention aims to propose a fisheye lens to solve the problem that current fisheye lenses cannot simultaneously achieve a large field of view, high resolution, low distortion, large aperture, small size and low cost.

[0006] This invention provides a fisheye 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, and a sixth lens. The first lens is a convex-concave lens with negative optical power; the second lens is a lens with negative optical power and a concave image side; the third lens is a convex-concave lens with positive optical power; the fourth lens is a concave-convex lens with positive optical power; the fifth lens is a convex-convex lens with positive optical power; and the sixth lens is a concave-convex lens with negative optical power. The effective focal length F5 of the fifth lens, the effective focal length F6 of the sixth lens, and the total effective focal length F of the fisheye lens satisfy the following relationship: -2.23 ≤ F5 * F6 / F ≤ -1.73.

[0007] In a preferred embodiment of the present invention, the maximum effective full aperture D1 of the first lens and the effective focal length F1 of the first lens satisfy the following relationship:

[0008] -1.54≤D1 / F1≤-1.27.

[0009] In a preferred embodiment of the present invention, the combined effective focal length F123 of the first lens to the third lens and the total effective focal length F of the fisheye lens satisfy the following relationship:

[0010] -2.14≤F123 / F≤-1.87.

[0011] In a preferred embodiment of the present invention, the radius of curvature R4 of the image-side surface of the second lens and the effective focal length F2 of the second lens satisfy the following relationship:

[0012] -0.59≤R4 / F2≤-0.50.

[0013] In a preferred embodiment of the present invention, the effective focal length F2 of the second lens and the effective focal length F3 of the third lens satisfy the following relationship:

[0014] -0.36≤F2 / F3≤-0.28.

[0015] In a preferred embodiment of the present invention, the effective focal length F2 of the second lens, the effective focal length F3 of the third lens, and the total effective focal length F of the fisheye lens satisfy the following relationship:

[0016] 3.13≤(F2+F3) / F≤5.92.

[0017] In a preferred embodiment of the present invention, the effective focal length F3 of the third lens and the total effective focal length F of the fisheye lens satisfy the following relationship:

[0018] 4.93≤F3 / F≤8.21.

[0019] In a preferred embodiment of the present invention, the effective focal length F4 of the fourth lens and the total effective focal length F of the fisheye lens satisfy the following relationship:

[0020] 3.83≤F4 / F≤4.58.

[0021] In a preferred embodiment of the present invention, the distance CT56 from the center of the object side of the fifth lens to the center of the image side of the sixth lens on the optical axis and the total optical length TTL of the fisheye lens satisfy the following relationship:

[0022] 0.24≤CT56 / TTL≤0.27.

[0023] In a preferred embodiment of the present invention, the maximum effective full aperture Dmax of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens, and the total optical length TTL of the fisheye lens satisfy the following relationship:

[0024] 1.06≤TTL / Dmax≤1.15.

[0025] In a preferred embodiment of the present invention, the maximum effective full aperture D3 of the third lens and the maximum effective full aperture D4 of the fourth lens satisfy the following relationship:

[0026] 1.47≤D3 / D4≤1.69.

[0027] In a preferred embodiment of the present invention, the radius of curvature R51 of the object side of the fifth lens, the radius of curvature R52 of the image side of the fifth lens, the radius of curvature R61 of the object side of the sixth lens, and the radius of curvature R62 of the image side of the sixth lens satisfy the following relationship:

[0028] -0.94≤((R51+R52)*(R61+R62)) / ((R51-R52)*(R61-R62))≤-0.83.

[0029] The fisheye lens of this invention can simultaneously meet the requirements of a large field of view, high imaging quality, low distortion, large aperture, miniaturization and low cost. It can meet the requirements of an absolute F-Theta distortion of less than or equal to 6%, a maximum field of view of up to 206°, a total optical system length TTL≤7mm, and a large aperture FNO≤1.81. 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 1 This is a schematic diagram of the structure of a fisheye lens according to the first embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of F-Theta distortion of a fisheye lens according to the first embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the structure of a fisheye lens according to the second embodiment of the present invention;

[0034] Figure 4This is a schematic diagram of F-Theta distortion of a fisheye lens according to the second embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the structure of a fisheye lens according to the third embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of F-Theta distortion of a fisheye lens according to the third embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the structure of a fisheye lens according to the fourth embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of F-Theta distortion of a fisheye lens according to the fourth embodiment of the present invention. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] like Figure 1 , Figure 3 , Figure 5 , Figure 7 The diagram shown is a structural schematic of a fisheye lens according to an embodiment of the present invention. The fisheye lens of this embodiment, 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, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a flat plate CG, and an image plane IMA.

[0042] The first lens L1 is a convex-concave lens with negative optical power, which can prevent the light entering the optical system from being too divergent, effectively control the rear aperture of the optical system, facilitate the vertical miniaturization of the optical lens, and can converge the incident light into the optical system as much as possible, which is beneficial for a large field of view.

[0043] The second lens L2 is a lens with negative optical power and a concave image side, which is beneficial for further light collection, allowing as much large-angle light as possible to enter the optical system and effectively improving the illumination of the optical system.

[0044] The third lens, L3, is a convex-concave lens with positive optical power. The second lens, L2, and the third lens, L3, have a combination of positive and negative optical powers, which helps to eliminate chromatic aberration, correct astigmatism, improve resolution, and also help to reduce the angle of light deflection, thus reducing system sensitivity.

[0045] The fourth lens, L4, is a concave-convex lens with positive optical power, which helps to raise the light, balance aberrations, and improve illumination while meeting the requirements for image size.

[0046] The aperture stop STO is positioned between the third lens L3 and the fourth lens L4, which can effectively gather the light entering the optical system, shorten the overall length of the optical system, and reduce the aperture of the front and rear lens groups.

[0047] The fifth lens, L5, is a convex-convex lens with positive optical power.

[0048] The sixth lens, L6, is a concave-convex lens with negative optical power.

[0049] In a preferred embodiment of the present invention, the fifth lens L5 and the sixth lens L6 are cemented together to form a cemented doublet lens group, which helps to reduce tolerance sensitivity, correct aberrations, and improve image quality. It also facilitates the miniaturization of the optical system. Furthermore, the cementation of the two lenses, combined with the use of a glass lens with an ND > 1.75 for the first lens L1, effectively corrects distortion, ensuring that the absolute value of F-Theta distortion is less than or equal to 6%.

[0050] In a preferred embodiment of the present invention, the first lens L1 is a glass spherical lens, and the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all plastic aspherical lenses. Using a 1G5P glass-plastic lens combination can significantly reduce costs, while using five aspherical lenses helps correct system aberrations, improve resolution, and correct distortion, ensuring that the absolute value of F-Theta distortion is less than or equal to 6%.

[0051] In a preferred embodiment of the present invention, the effective focal length F5 of the fifth lens L5, the effective focal length F6 of the sixth lens L6, and the total effective focal length F of the fisheye lens satisfy: -2.23 ≤ F5 * F6 / F ≤ -1.73. The fifth lens L5 and the sixth lens L6 form a cemented doublet lens group. Reasonably controlling the positive and negative optical power matching of the fifth lens L5 and the sixth lens L6 helps reduce the tolerance sensitivity generated during the assembly of the lens units. Simultaneously, it corrects the aberrations caused by the deflected rays of each lens located on the object side of the cemented doublet lens group L5 and L6, thereby improving image quality.

[0052] In a preferred embodiment of the present invention, the maximum effective aperture D1 and the effective focal length F1 of the first lens L1 satisfy the following relationship: -1.54 ≤ D1 / F1 ≤ -1.27. This allows for a reasonable configuration of the effective aperture and focal length of the object-side surface of the first lens L1, which is beneficial for allowing large-angle light rays to enter the optical system and expanding the maximum field of view of the optical system, so that the maximum field of view can reach 206°.

[0053] In a preferred embodiment of the present invention, the combined effective focal length F123 of the first lens L1 to the third lens L3 and the total effective focal length F of the fisheye lens satisfy the following relationship: -2.14 ≤ F123 / F ≤ -1.87. By rationally configuring the focal lengths of the first lens L1, the second lens L2, and the third lens L3, it is beneficial to allow more light to enter the optical system smoothly, control the light path of the optical system, achieve stable imaging, and improve the resolving power of the lens.

[0054] In a preferred embodiment of the present invention, the radius of curvature R4 of the image side surface of the second lens L2 and the effective focal length F2 of the second lens F2 satisfy the following relationship: -0.59 ≤ R4 / F2 ≤ -0.50. This setting controls the light path, making it smoother, reducing tolerance sensitivity, and improving lens yield.

[0055] In a preferred embodiment of the present invention, the effective focal length F2 of the second lens F2 and the effective focal length F3 of the third lens L3 satisfy the following relationship: -0.36 ≤ F2 / F3 ≤ -0.28. The effective focal length F2 of the second lens F2, the effective focal length F3 of the third lens L3, and the total effective focal length F of the fisheye lens satisfy the following relationship: 3.13 ≤ (F2 + F3) / F ≤ 5.92. By reasonably configuring the positive and negative optical powers of the second lens L2 and the third lens L3, it helps to eliminate chromatic aberration, correct astigmatism, and improve resolution; and it also helps to reduce the light deflection angle and reduce system sensitivity.

[0056] In a preferred embodiment of the present invention, the effective focal length F3 of the third lens L3 and the total effective focal length F of the fisheye lens satisfy the following relationship: 4.93 ≤ F3 / F ≤ 8.21. By setting the third lens L3 to a positive optical power, it can be reasonably matched with the negative optical power of the second lens L2, which is beneficial to controlling the optical path and improving the overall illumination of the optical system.

[0057] In a preferred embodiment of the present invention, the effective focal length F4 of the fourth lens L4 and the total effective focal length F of the fisheye lens satisfy the following relationship: 3.83 ≤ F4 / F ≤ 4.58. By setting the fourth lens L4 as a positive power lens, it is beneficial to raise the light intensity, balance aberrations, and improve illumination while meeting the image size requirements.

[0058] In a preferred embodiment of the present invention, the distance CT56 on the optical axis from the center of the object side of the fifth lens L5 to the center of the image side of the sixth lens L6 and the total optical length TTL of the fisheye lens satisfy the following relationship: 0.24≤CT56 / TTL≤0.27. By setting the fifth and sixth lenses as a cemented doublet lens group and reasonably controlling the positive and negative optical power matching of the fifth and sixth lenses, it is beneficial to reduce the air gap between the lenses, thereby reducing the total length of the optical system, making the total optical system length TTL≤7mm; at the same time, it reduces the assembly components between the lenses, reduces the number of processes, lowers the cost, and is conducive to the lateral miniaturization of the lens.

[0059] In a preferred embodiment of the present invention, the maximum effective full aperture Dmax of the first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, and sixth lens L6 and the total optical length TTL of the fisheye lens satisfy the following relationship: 1.06 ≤ TTL / Dmax ≤ 1.15. Controlling the maximum full aperture among all lenses in the optical system, while achieving lateral miniaturization of the lens, is beneficial for achieving longitudinal miniaturization of the lens.

[0060] In a preferred embodiment of the present invention, the maximum effective full aperture D3 of the third lens L3 and the maximum effective full aperture D4 of the fourth lens L4 satisfy the following relationship: 1.47≤D3 / D4≤1.69. By setting the aperture of the lenses before and after the aperture stop STO, good light transmission is achieved, enabling the lens to ensure maximum light transmission while satisfying a large field of view, thus achieving an aperture FNO≤1.81.

[0061] In a preferred embodiment of the present invention, the curvature radii R51 and R52 of the object-side surface of the fifth lens L5, and R61 and R62 of the object-side surface of the sixth lens L6 satisfy: -0.94≤((R51+R52)*(R61+R62)) / ((R51-R52)*(R61-R62))≤-0.83. By reasonably controlling the curvature radii of the object-side and image-side surfaces of the fifth lens L5 and the sixth lens L6, the deviation of the incident and exit angles of light in different fields of view can be reduced, resulting in a smooth transition of light, thereby reducing tolerance sensitivity and improving lens yield.

[0062] The fisheye lens of this invention can simultaneously achieve a large field of view, high imaging quality, low distortion, and large aperture, while also meeting the requirements of small size and low cost. It can meet the requirements of an absolute F-Theta distortion of less than or equal to 6%, a maximum field of view of up to 206°, a total optical system length of TTL ≤ 7mm, and a large aperture of FNO ≤ 1.81.

[0063] The fisheye lens of the present invention will be specifically described below with reference to four embodiments, accompanying drawings, and tables. In the various embodiments below, the aperture stop STO is referred to as one side, and the image plane IMA is referred to as another side.

[0064] The parameters for each embodiment that meets the above conditions are shown in Table 1 below:

[0065]

[0066] Table 1

[0067] In an embodiment of the present invention, the aspherical lens of the fisheye lens satisfies the following formula:

[0068]

[0069] 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.

[0070] Example 1

[0071] like Figure 1 The diagram shown is a schematic representation of the optical structure of a fisheye lens according to Embodiment 1 of the present invention. In this embodiment, the second lens L2 is a concave-convex lens.

[0072] In Example 1, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the fisheye lens are shown in the table below (Table 2):

[0073] 1 spherical 5.340 0.40 1.76 52.34 2 spherical 2.075 1.27 3 aspherical -14.148 0.27 1.54 55.98 4 aspherical 0.651 0.53 5 aspherical 1.570 0.56 1.64 23.53 6 aspherical 4.251 0.21 STO spherical Infinity 0.03 8 aspherical -4.995 0.71 1.54 55.98 9 aspherical -1.132 0.08 10 aspherical 1.334 1.21 1.54 55.98 11 aspherical -0.506 0.50 1.66 20.37 12 aspherical -1.473 0.33 13 spherical Infinity 0.21 1.52 64.21 14 spherical Infinity 0.40 IMA spherical Infinity 0.00

[0074] Table 2

[0075] In Example 1, the K-value and aspherical coefficient of the fisheye lens are shown in the table below (Table 3):

[0076]

[0077]

[0078] Table 3

[0079] Combination Figure 1-2As shown in Tables 1-3 above, this embodiment, through the reasonable allocation of lens power, shape, and optical parameters, can simultaneously achieve a large field of view, high image quality, low distortion, and large aperture for a fisheye lens, while also satisfying the requirements of small size and low cost. The fisheye lens of this embodiment achieves a field of view (FOV) of 206°, an aperture factor (FNO) of 1.80, and an absolute F-Theta distortion of 5.6%.

[0080] Example 2

[0081] like Figure 3 The diagram shown is a schematic representation of the optical structure of a fisheye lens according to Embodiment 2 of the present invention. In this embodiment, the second lens L2 is a concave-convex lens.

[0082] In Example 2, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the fisheye lens are shown in the table below (Table 4):

[0083] 1 spherical 5.356 0.40 1.76 52.34 2 spherical 2.060 1.26 3 aspherical -17.112 0.22 1.54 55.98 4 aspherical 0.649 0.55 5 aspherical 1.577 0.57 1.64 23.53 6 aspherical 5.064 0.24 STO spherical Infinity 0.02 8 aspherical -3.897 0.66 1.54 55.98 9 aspherical -1.141 0.08 10 aspherical 1.322 1.21 1.54 55.98 11 aspherical -0.513 0.49 1.66 20.37 12 aspherical -1.456 0.31 13 spherical Infinity 0.21 1.52 64.21 14 spherical Infinity 0.42 IMA spherical Infinity 0.00

[0084] Table 4

[0085] In Example 2, the K-value and aspherical coefficient of the fisheye lens are shown in the table below (Table 5):

[0086] 3 0.00 3.91E-02 -1.99E-02 5.65E-03 -7.46E-04 0.00E+00 0.00E+00 0.00E+00 4 -1.13 4.65E-01 -1.40E-01 2.06E+00 1.09E+00 -9.55E+00 1.45E+01 0.00E+00 5 -0.49 2.69E-01 1.29E-01 1.95E-01 7.18E-01 1.76E-01 -3.17E+00 0.00E+00 6 6.71 6.02E-01 1.26E+00 -3.00E+00 1.53E+00 1.23E+02 -3.81E+02 0.00E+00 8 0.00 5.71E-01 -7.35E-01 2.37E+00 -4.68E+01 3.88E+01 9.73E+02 0.00E+00 9 0.38 8.29E-03 1.19E-01 -4.05E-01 -4.86E-01 4.16E+00 -3.62E+00 0.00E+00 10 -0.34 -6.01E-02 7.06E-02 -2.42E-01 2.85E-01 -7.79E-02 -4.45E-02 0.00E+00 11 -2.75 -1.19E+00 2.88E+00 -3.24E+00 2.15E+00 -1.03E+00 5.32E-02 0.00E+00 12 -7.70 -1.87E-02 2.96E-01 -1.78E-01 4.03E-02 2.61E-02 -5.18E-02 0.00E+00

[0087] Table 5

[0088] Combination Figure 3-4 As shown in Tables 1 and 4-5 above, this embodiment, through the reasonable allocation of lens power, shape, and optical parameters, can simultaneously achieve a large field of view, high image quality, low distortion, and large aperture for a fisheye lens, while also satisfying the requirements of small size and low cost. The fisheye lens of this embodiment achieves a field of view (FOV) of 206°, an aperture factor (FNO) of 1.77, and an absolute F-Theta distortion of 5.7%.

[0089] Example 3

[0090] like Figure 5 The diagram shown is a schematic representation of the optical structure of a fisheye lens according to Embodiment 3 of the present invention. In this embodiment, the second lens L2 is a plano-concave lens.

[0091] In Example 3, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the fisheye lens are shown in the table below (Table 6):

[0092]

[0093]

[0094] Table 6

[0095] In Example 3, the K-value and aspherical coefficient of the fisheye lens are shown in the table below (Table 7):

[0096] 3 0.00 4.02E-02 -1.46E-02 1.29E-03 1.40E-04 0.00E+00 0.00E+00 0.00E+00 4 -1.57 5.54E-01 -7.09E-02 6.82E-01 2.78E+00 -3.92E+00 0.00E+00 0.00E+00 5 0.43 2.10E-01 2.59E-01 1.91E-01 6.91E-01 -3.05E+00 0.00E+00 0.00E+00 6 -5.75 7.09E-01 1.12E+00 3.87E+00 -9.78E+00 1.69E+00 0.00E+00 0.00E+00 8 0.00 3.21E-01 6.04E-01 5.45E+00 -5.86E+01 1.59E+02 0.00E+00 0.00E+00 9 0.23 -1.27E-02 3.74E-03 -6.17E-02 -4.16E-01 9.06E-01 0.00E+00 0.00E+00 10 -0.23 -6.15E-02 9.47E-02 -2.56E-01 3.12E-01 -1.69E-01 0.00E+00 0.00E+00 11 -3.47 -1.27E+00 2.84E+00 -3.38E+00 1.93E+00 -2.53E-01 0.00E+00 0.00E+00 12 -12.93 -1.08E-02 2.66E-01 -1.38E-01 -1.68E-02 1.43E-02 0.00E+00 0.00E+00

[0097] Table 7

[0098] Combination Figure 5-6 As shown in Tables 1 and 6-7 above, this embodiment, through the reasonable allocation of lens power, shape, and optical parameters, can simultaneously achieve a large field of view, high image quality, low distortion, and large aperture for a fisheye lens, while also satisfying the requirements of small size and low cost. The fisheye lens of this embodiment achieves a field of view (FOV) of 206°, an aperture factor (FNO) of 1.81, and an absolute F-Theta distortion of 6%.

[0099] Example 4

[0100] like Figure 7 The diagram shown is a schematic representation of the optical structure of a fisheye lens according to Embodiment 4 of the present invention. In this embodiment, the second lens L2 is a convex-concave lens.

[0101] In Example 4, the radius of curvature R, thickness d, refractive index Nd, and Abbe number Vd of each surface of the fisheye lens are shown in the table below (Table 8):

[0102]

[0103]

[0104] Table 8

[0105] In Example 4, the K-value and aspherical coefficient of the fisheye lens are shown in the table below (Table 9):

[0106] 3 0.00 4.11E-02 -1.41E-02 1.20E-03 5.60E-05 0.00E+00 0.00E+00 0.00E+00 4 -1.37 5.75E-01 -2.34E-03 8.27E-01 2.95E+00 -3.60E+00 0.00E+00 0.00E+00 5 0.33 2.44E-01 3.05E-01 2.60E-02 4.11E-01 -2.79E+00 0.00E+00 0.00E+00 6 -7.41 7.12E-01 1.11E+00 2.47E+00 -1.08E+01 7.84E+00 0.00E+00 0.00E+00 8 0.00 3.13E-01 4.53E-01 5.26E+00 -5.80E+01 1.60E+02 0.00E+00 0.00E+00 9 0.24 -1.86E-02 3.19E-02 -4.92E-02 -4.39E-01 7.22E-01 0.00E+00 0.00E+00 10 -0.19 -5.77E-02 9.48E-02 -2.55E-01 3.14E-01 -1.71E-01 0.00E+00 0.00E+00 11 -3.01 -1.28E+00 2.89E+00 -3.39E+00 1.88E+00 -2.37E-01 0.00E+00 0.00E+00 12 -10.95 1.31E-03 2.67E-01 -1.29E-01 -4.38E-03 -5.41E-03 0.00E+00 0.00E+00

[0107] Table 9

[0108] Combination Figure 7-8 As shown in Tables 1 and 8-9 above, this embodiment, through the reasonable allocation of lens power, shape, and optical parameters, can simultaneously achieve a large field of view, high image quality, low distortion, and large aperture for a fisheye lens, while also satisfying the requirements of small size and low cost. The fisheye lens of this embodiment achieves a field of view (FOV) of 206°, an aperture factor (FNO) of 1.81, and an absolute F-Theta distortion of 6%.

[0109] 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 fisheye lens, comprising, in sequence along the optical axis from the object side to the image side: The system comprises six lenses with optical power: a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), and a sixth lens (L6). Its characteristic is that... The first lens (L1) is a convex-concave lens with negative optical power; The second lens (L2) is a lens with negative optical power and a concave image side; The third lens (L3) is a convex-concave lens with positive optical power; The fourth lens (L4) is a concave-convex lens with positive optical power; The fifth lens (L5) is a convex-convex lens with positive optical power; The sixth lens (L6) is a concave-convex lens with negative optical power; The effective focal length F5 of the fifth lens (L5), the effective focal length F6 of the sixth lens (L6), and the total effective focal length F of the fisheye lens satisfy the following relationship: -2.23≤F5*F6 / F≤-1.

73.

2. The fisheye lens according to claim 1, characterized in that, The maximum effective full aperture D1 of the first lens (L1) and the effective focal length F1 of the first lens (L1) satisfy the following relationship: -1.54≤D1 / F1≤-1.

27.

3. The fisheye lens according to claim 1, characterized in that, The combined effective focal length F123 of the first lens (L1) to the third lens (L3) and the total effective focal length F of the fisheye lens satisfy the following relationship: -2.14≤F123 / F≤-1.

87.

4. The fisheye lens according to claim 1, characterized in that, The radius of curvature R4 of the image-side surface of the second lens (L2) and the effective focal length F2 of the second lens (L2) satisfy the following relationship: -0.59≤R4 / F2≤-0.

50.

5. The fisheye lens according to claim 1, characterized in that, The effective focal length F2 of the second lens (L2) and the effective focal length F3 of the third lens (L3) satisfy the following relationship: -0.36≤F2 / F3≤-0.

28.

6. The fisheye lens according to claim 1, characterized in that, The effective focal length F2 of the second lens (L2), the effective focal length F3 of the third lens (L3), and the total effective focal length F of the fisheye lens satisfy the following relationship: 3.13≤(F2+F3) / F≤5.

92.

7. The fisheye lens according to claim 1, characterized in that, The effective focal length F3 of the third lens (L3) and the total effective focal length F of the fisheye lens satisfy the following relationship: 4.93≤F3 / F≤8.

21.

8. The fisheye lens according to claim 1, characterized in that, The effective focal length F4 of the fourth lens (L4) and the total effective focal length F of the fisheye lens satisfy the following relationship: 3.83≤F4 / F≤4.

58.

9. The fisheye lens according to claim 1, characterized in that, The distance CT56 between the center of the object side of the fifth lens (L5) and the center of the image side of the sixth lens (L6) on the optical axis and the total optical length TTL of the fisheye lens satisfy the following relationship: 0.24≤CT56 / TTL≤0.

27.

10. The fisheye lens according to claim 1, characterized in that, The maximum effective full aperture Dmax of the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens (L6) and the total optical length TTL of the fisheye lens satisfy the following relationship: 1.06≤TTL / Dmax≤1.

15.

11. The fisheye lens according to claim 1, characterized in that, The maximum effective full aperture D3 of the third lens (L3) and the maximum effective full aperture D4 of the fourth lens (L4) satisfy the following relationship: 1.47≤D3 / D4≤1.

69.

12. The fisheye lens according to claim 1, characterized in that, The radius of curvature R51 of the object side of the fifth lens (L5), the radius of curvature R52 of the image side of the fifth lens (L5), the radius of curvature R61 of the object side of the sixth lens (L6), and the radius of curvature R62 of the image side of the sixth lens (L6) satisfy the following relationship: -0.94≤((R51+R52)*(R61+R62)) / ((R51-R52)*(R61-R62))≤-0.83.

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