L-shaped fisheye lens

Abstract

The application discloses an L-shaped fisheye lens, which comprises a first lens, a second lens, a third lens, a plane mirror, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence along an optical axis from an object plane to an image plane; the first lens is a glass spherical lens with negative focal power; the second lens is a plastic aspherical lens with negative focal power; the third lens is a glass spherical lens with positive focal power; the fourth lens is a plastic aspherical lens with negative focal power; the fifth lens is a glass aspherical lens with positive focal power; the sixth lens is a glass spherical lens with positive focal power; the seventh lens is a glass spherical lens with negative focal power; and the eighth lens is a plastic aspherical lens with positive focal power. Through optimization of the focal power and relative positions of the lenses, the design of the L-shaped fisheye lens with a large aperture, high illumination, super-high resolving power and small volume can be realized, and the market demand for the L-shaped fisheye lens can be met.

Description

Technical Field

[0001] The present invention relates to the field of optical device technology, and in particular to an L-shaped fisheye lens. Background Technology

[0002] A fisheye lens is an optical system with a large field of view and a large aperture. Because it can obtain all the optical information within a hemispherical or even a super-hemispherical spatial field of view without rotating the lens, fisheye lenses are widely used in fields such as security monitoring, automotive applications, unmanned equipment, and sports photography.

[0003] However, existing fisheye lenses still have many shortcomings, such as poor edge resolution when the angle is greater than 190°; severe edge chromatic aberration, which easily leads to purple fringing; significant sacrifice of relative illumination at the edge field of view when the light is large and the angle is large; and large overall lens length, which can no longer meet the increasingly demanding imaging requirements. Summary of the Invention

[0004] This invention provides an L-shaped fisheye lens. This patent adopts an optical system structure of 4G1GM3P plus a plane mirror. By optimizing the optical power of each lens element and the relative position of each lens element, the design of an L-shaped fisheye lens with large aperture, high illumination, ultra-high resolution and small size is finally realized, meeting the market demand for L-shaped fisheye lenses.

[0005] This invention provides an L-shaped fisheye lens, comprising a first lens, a second lens, a third lens, a plane mirror, a fourth lens, an aperture stop, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis from the object plane to the image plane;

[0006] The first lens is a glass spherical lens with negative optical power; the second lens is a plastic aspherical lens with negative optical power; the third lens is a glass spherical lens with positive optical power; the fourth lens is a plastic aspherical lens with negative optical power; the fifth lens is a glass aspherical lens with positive optical power; the sixth lens is a glass spherical lens with positive optical power; the seventh lens is a glass spherical lens with negative optical power; and the eighth lens is a plastic aspherical lens with positive optical power.

[0007] Optionally, the angle between the plane mirror and the optical axis is 45°.

[0008] Optionally, the optical parameters of the L-shaped fisheye lens meet the following requirements:

[0009] 0.60 <T 后组 / T 前组 <0.72;

[0010] Among them, T 后组T is the length along the optical axis from the object surface of the fourth lens to the image surface of the eighth lens. 前组 It is the length along the optical axis from the object surface of the first lens to the image surface of the third lens.

[0011] Optionally, the optical parameters of the L-shaped fisheye lens meet the following requirements:

[0012] 0.64≤T 前组 / D1≤0.73;

[0013] Among them, T 前组 D1 is the length along the optical axis from the object surface of the first lens to the image surface of the third lens, and D1 is the effective optical diameter of the object surface of the first lens.

[0014] Optionally, the optical parameters of the L-shaped fisheye lens meet the following requirements:

[0015] 17.20≤f*D1 / WFNO≤19.91;

[0016] Where f is the overall focal length of the L-shaped fisheye lens, D1 is the effective optical diameter of the object surface of the first lens, and WFNO is the working aperture number of the L-shaped fisheye lens.

[0017] Optionally, the optical power of the first lens to the eighth lens satisfies the following formula:

[0018] -0.20≤Φ1 / Φ≤-0.10;-0.26≤Φ2 / Φ≤-0.15;0.05≤Φ3 / Φ≤0.13;

[0019] 0.36≤Φ5 / Φ≤0.46; 0.23≤Φ6 / Φ≤0.35; -0.74≤Φ7 / Φ≤-0.52; 0.16≤Φ8 / Φ≤0.30;

[0020] Wherein, Φ1, Φ2, Φ3, Φ5, Φ6, Φ7, and Φ8 represent the optical power of the first lens, the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens, respectively, and Φ represents the overall optical power of the L-shaped fisheye lens.

[0021] Optionally, the refractive index and Abbe number of the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens satisfy the following:

[0022] 1.73 <Nd1,37.00<Vd1<47.91;1.73<Nd3,15.60<Vd3<25.00;

[0023] 1.41 <Nd5<1.62,52.00<Vd5<99.8;1.42<Nd6<1.75,48.00<Vd6<98.00;

[0024] 1.55 <Nd7<1.85,21.00<Vd7<33.00;

[0025] Wherein, Nd1, Nd3, Nd5, Nd6, and Nd7 represent the refractive indices of the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens, respectively, and Vd1, Vd3, Vd5, Vd6, and Vd7 represent the Abbe numbers of the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

[0026] Optionally, the sixth lens and the seventh lens can be cemented together to form a cemented doublet lens.

[0027] Optionally, along the optical axis from the object plane to the image plane, the surface of the lens facing the object plane is called the object-side surface, and the surface of the lens closer to the image plane is called the image-side surface.

[0028] The object side of the first lens is convex, and the image side is concave.

[0029] The object-side surface of the second lens is convex, and the image-side surface is concave.

[0030] The image-side surface of the third lens is convex, and the image-side surface is concave.

[0031] The object-side surface of the fourth lens is concave, and the image-side surface is convex.

[0032] The image-side surface of the fifth lens is convex.

[0033] The object-side surface of the sixth lens is convex, and the image-side surface is also convex.

[0034] The object-side surface of the seventh lens is concave, and the image-side surface is also concave.

[0035] The object-side surface of the eighth lens is convex, and the image-side surface is also convex.

[0036] Optionally, a filter may also be included, which is located between the eighth lens and the image plane.

[0037] The L-shaped fisheye lens provided in this invention includes eight lenses arranged sequentially from the object plane to the image plane along the optical axis. By reasonably matching the optical power combinations of the first to eighth lenses as negative, negative, positive, negative, positive, positive, negative, and positive, as well as the position, shape, and material of each lens, the design of an infrared confocal L-shaped fisheye lens with ultra-large light transmission, large target area, and ultra-wide angle is realized, meeting the market demand for L-shaped fisheye lenses. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of an L-shaped fisheye lens provided in Embodiment 1 of this application;

[0039] Figure 2 This application provides an axial aberration curve for an L-shaped fisheye lens in Embodiment 1.

[0040] Figure 3 This application provides a vertical axis chromatic aberration curve for an L-shaped fisheye lens in Embodiment 1.

[0041] Figure 4 An illuminance curve diagram of an L-shaped fisheye lens is provided for Embodiment 1 of this application;

[0042] Figure 5 This is a schematic diagram of the structure of an L-shaped fisheye lens provided in Embodiment 2 of this application;

[0043] Figure 6 This application provides an axial aberration curve for an L-shaped fisheye lens in Embodiment 2.

[0044] Figure 7 This application provides a lateral chromatic aberration curve for an L-shaped fisheye lens in Embodiment 2.

[0045] Figure 8 This application provides an illuminance curve diagram for an L-shaped fisheye lens in Embodiment 2.

[0046] Figure 9 This is a schematic diagram of the structure of an L-shaped fisheye lens provided in Embodiment 3 of this application;

[0047] Figure 10 This application provides an axial aberration curve for an L-shaped fisheye lens in Embodiment 3.

[0048] Figure 11 This application provides a vertical axis chromatic aberration curve for an L-shaped fisheye lens in Embodiment 3.

[0049] Figure 12 This application provides an illuminance curve diagram for an L-shaped fisheye lens in Embodiment 3.

[0050] Figure 13 This is a schematic diagram of the structure of an L-shaped fisheye lens provided in Embodiment 4 of this application;

[0051] Figure 14 This application provides an axial aberration curve for an L-shaped fisheye lens in Embodiment 4.

[0052] Figure 15 This application provides a vertical axis chromatic aberration curve for an L-shaped fisheye lens in Embodiment 4.

[0053] Figure 16This application provides an illuminance curve diagram for an L-shaped fisheye lens in Embodiment 4. Detailed Implementation

[0054] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0055] Figure 1 This is a structural schematic diagram of an L-shaped fisheye lens provided in Embodiment 1 of this application, with reference to... Figure 1 An L-shaped fisheye lens provided in this embodiment of the invention includes a first lens L1, a second lens L2, a third lens L3, a plane mirror T, a fourth lens L4, an aperture stop STO, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 arranged sequentially along the optical axis from the object plane to the image plane. Specifically, the first lens L1 is a glass spherical lens with negative optical power; the second lens L2 is a plastic aspherical lens with negative optical power; the third lens L3 is a glass spherical lens with positive optical power; the fourth lens L4 is a plastic aspherical lens with negative optical power; the fifth lens L5 is a glass aspherical lens with positive optical power; the sixth lens L6 is a glass spherical lens with positive optical power; the seventh lens L7 is a glass spherical lens with negative optical power; and the eighth lens L8 is a plastic aspherical lens with positive optical power.

[0056] refer to Figure 1 In this embodiment, the first lens L1, the second lens L2, the third lens L3, the plane mirror T, the fourth lens L4, the aperture stop STO, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are arranged sequentially along the optical axis from the object plane to the image plane. It should be noted that... Figure 1 The structural diagrams in the subsequent embodiments are for illustrative purposes only, and shapes such as aspherical surfaces are not represented in accordance with actual conditions.

[0057] Optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and its value is the reciprocal of the focal length. It characterizes the ability of an L-shaped fisheye lens to deflect light. The larger the absolute value of the optical power, the stronger the bending ability of light; the smaller the absolute value of the optical power, the weaker the bending ability of light. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a lens group formed by multiple lenses.

[0058] refer to Figure 1The optical power combinations of the first lens L1 to the eighth lens L8 provided in this application embodiment satisfy negative, negative, positive, negative, positive, positive, negative, and positive. The first lens L1, the second lens L2, and the third lens L3 form the front optical system of the L-shaped fisheye lens, and the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 form the rear optical system of the L-shaped fisheye lens.

[0059] In the front optical system, the first lens L1 and the second lens L2 with negative optical power diverge the incident light, which can increase the entrance pupil of the light, while the third lens L3 with positive optical power converges the light and adjusts the beam.

[0060] A plane mirror T is provided between the third lens L3 and the fourth lens L4. Optionally, the plane mirror T has an angle of 45° with the optical axis, which can also be understood as an inclination angle of 45°. This is used to change the direction of light propagation, which helps to reduce the size of the L-shaped fisheye lens.

[0061] In the rear optical system, the fourth lens L4 with negative optical power diverges the light rays, while the fifth lens L5 and the sixth lens L6 with positive optical power converge the light rays. The seventh lens L7 with negative optical power diverges the light rays, and the eighth lens L8 with positive optical power converges the light rays to form an image on the image plane IMA.

[0062] Considering that glass is more stable than plastic in high and low temperature environments, and that glass lenses have stronger light-reflecting capabilities, this application uses glass spherical lenses for the first lens L1, third lens L3, sixth lens L6, and seventh lens L7, and a glass aspherical lens for the fifth lens L5. This helps reduce the number of lenses, decrease lens size, reduce focus drift caused by thermal effects, and improve lens stability. Given that aspherical lenses have excellent control over optical aberrations and higher-order optical aberrations, plastic aspherical lenses are used for the second lens L2, fourth lens L4, and eighth lens L8. This reduces lens costs while simultaneously controlling optical aberrations and higher-order optical aberrations.

[0063] It should be noted that the materials of the glass spherical lens and the plastic aspherical lens are various types of glass known to those skilled in the art, and this application embodiment will not elaborate on or limit them.

[0064] In this embodiment of the application, the aspherical lens of the L-shaped fisheye lens satisfies the following formula:

[0065]

[0066] Where z represents the axial sagitta in the Z direction of the aspherical surface; r represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the fitted conic coefficients; A, B, C, D, E, F, and G represent the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial, respectively.

[0067] This application, through the reasonable combination of the optical power of the first lens L1 to the eighth lens L8, is conducive to the design of an L-shaped fisheye lens with large aperture, high illumination, ultra-high resolution, and small size.

[0068] In this embodiment, the aperture stop STO includes an aperture stop and a field stop. The aperture stop refers to the stop that restricts the light beam the most, and the field stop refers to the stop that restricts the field of view (size) the most. The aperture stop STO is set between the fourth lens L4 with negative optical power and the fifth lens L5 with positive optical power, which helps to restrict the entry of stray light from the edges, thereby improving the image quality.

[0069] This application uses a combination of 4 spherical glass pieces, 1 aspherical glass piece, and 3 aspherical plastic pieces, which can effectively correct aberrations and ensure ultra-high resolution. At the same time, the addition of a plane mirror helps to reduce the size of the lens, resulting in a high cost-performance ratio.

[0070] Optional, see reference Figure 1 Along the optical axis from the object plane to the image plane, the surface of the lens facing the object plane is called the object-side surface, and the surface of the lens closer to the image plane is called the image-side surface. The object-side surface of the first lens L1 is convex, and the image-side surface is concave. The object-side surface of the second lens L2 is convex, and the image-side surface is concave. The image-side surface of the third lens L3 is convex, and the image-side surface is concave. The object-side surface of the fourth lens L4 is concave, and the image-side surface is convex. The image-side surface of the fifth lens L5 is convex, and the image-side surface is convex. The object-side surface of the sixth lens L6 is convex, and the image-side surface is convex. The object-side surface of the seventh lens L7 is concave, and the image-side surface is concave. The object-side surface of the eighth lens L8 is convex, and the image-side surface is convex.

[0071] In this design, concave lenses diverge transmitted light, while convex lenses converge transmitted light. This application achieves clear imaging with an L-shaped fisheye lens by appropriately setting the surface shapes of the first lens L1 to the eighth lens L8.

[0072] Based on the above embodiments, refer to Figure 1 The optical parameters of the L-shaped fisheye lens satisfy:

[0073] 0.60 <T 后组 / T 前组 <0.72.

[0074] Among them, T 后组T is the length along the optical axis from the object surface of the fourth lens L4 to the image surface of the eighth lens L8. 前组 It is the length along the optical axis from the object surface of the first lens L1 to the image surface of the third lens L3.

[0075] Specifically, when the length ratio of the front optical system and the rear optical system of the L-shaped fisheye lens provided in this application embodiment is within this range, the lens structure can be made more compact, and installation space is provided for the plane mirror T between the third lens L3 and the fourth lens L4.

[0076] Based on the above embodiments, refer to Figure 1 The optical parameters of the L-shaped fisheye lens satisfy:

[0077] 0.64≤T 前组 / D1≤0.73.

[0078] Among them, T 前组 D1 is the length along the optical axis from the object surface of the first lens L1 to the image surface of the third lens L3, and D1 is the effective optical diameter of the object surface of the first lens L1.

[0079] The effective aperture in optical systems refers to the size of the aperture that actually participates in optical imaging or plays an effective role in light propagation. It plays a crucial role in analyzing the performance of optical systems, such as their light-gathering ability and resolution.

[0080] Specifically, when the effective optical diameter of the front group optical system of the L-shaped fisheye lens provided in this application embodiment and the object surface of the first lens L1 meet the above ratio range, it indicates that the shape and size of the first lens L1 meet the characteristics of the L-shaped fisheye lens and is conducive to the realization of a large angle of the L-shaped fisheye lens.

[0081] Based on the above embodiments, refer to Figure 1 The optical parameters of the L-shaped fisheye lens satisfy:

[0082] 17.20≤f*D1 / WFNO≤19.91.

[0083] Where f is the overall focal length of the L-shaped fisheye lens, D1 is the effective optical diameter of the object surface of the first lens L1, and WFNO is the working aperture of the L-shaped fisheye lens.

[0084] Specifically, when the L-shaped fisheye lens provided in this application embodiment meets the above ratio range, it is not only beneficial to achieve a large angle of the L-shaped fisheye lens, but also beneficial to achieve a large aperture, thereby improving the brightness of the L-shaped fisheye lens.

[0085] Based on the above embodiments, refer to Figure 1The optical power of the first lens L1 and the second lens L2 satisfy the following formulas: -0.20≤Φ1 / Φ≤-0.10; -0.26≤Φ2 / Φ≤-0.15. Wherein, Φ1 represents the optical power of the first lens L1, Φ2 represents the optical power of the second lens L2, and Φ represents the overall optical power of the L-shaped fisheye lens.

[0086] Specifically, in this embodiment, the first lens L1 is a convex-concave glass spherical lens, and the second lens L2 is a convex-concave plastic aspherical lens. When the optical power of the first lens L1 and the second lens L2 meets this condition, it can be ensured that the optical system can transmit light at a large angle, thus realizing the design of an L-shaped fisheye lens.

[0087] Based on the above embodiments, refer to Figure 1 The optical power of the third lens L3 satisfies the following formula: 0.05≤Φ3 / Φ≤0.13. Where Φ3 represents the optical power of the third lens L3, and Φ represents the overall optical power of the L-shaped fisheye lens.

[0088] Specifically, in this embodiment, the third lens L3 is a convex-concave glass spherical lens, and the fourth lens L4 is a concave-convex plastic aspherical lens. When the optical power of the third lens L3 meets this condition, it is beneficial to the convergence of light rays in the optical system, which in turn is beneficial to the installation of the plane mirror T. Furthermore, the cooperation between the third lens L3 and the fourth lens L4 is beneficial to the correction of field curvature and aberrations in the system.

[0089] Based on the above embodiments, refer to Figure 1 The optical power of the fifth lens L5 satisfies the following formula: 0.36≤Φ5 / Φ≤0.46. Where Φ5 represents the optical power of the fifth lens L5, and Φ represents the overall optical power of the L-shaped fisheye lens.

[0090] Specifically, the fifth lens L5 provided in this application embodiment is a biconvex glass aspherical lens. When the optical power of the fifth lens L5 is within this range, the light can be further reduced by a gentler angle of deviation, giving the optical system a more relaxed tolerance sensitivity. Furthermore, the use of glass aspherical lenses is beneficial for correcting spherical aberration and coma, which helps to improve the lens's resolving power.

[0091] Based on the above embodiments, refer to Figure 1 The optical power of the sixth lens L6 and the seventh lens L7 satisfies the following formula: 0.23≤Φ6 / Φ≤0.35; -0.74≤Φ7 / Φ≤-0.52. Where Φ6 represents the optical power of the sixth lens L6, Φ7 represents the optical power of the seventh lens L7, and Φ represents the overall optical power of the L-shaped fisheye lens.

[0092] Specifically, the sixth lens L6 provided in this application embodiment is a biconvex glass spherical lens, and the seventh lens L7 is a biconcave glass spherical lens. When the optical power of the sixth lens L6 and the seventh lens L7 meets this range, it is beneficial for the correction of system aberrations.

[0093] Based on the above embodiments, refer to Figure 1 The optical power of the eighth lens L8 satisfies the following formula: 0.16≤Φ8 / Φ≤0.30. Where Φ8 represents the optical power of the eighth lens L8, and Φ represents the overall optical power of the L-shaped fisheye lens.

[0094] Specifically, the eighth lens L8 provided in this application embodiment is a biconvex plastic aspherical lens with positive optical power. When the optical power of the eighth lens L8 meets this range, it is beneficial to correct system aberrations and to control the angle between the principal rays of the system light, so as to match the imaging detector (sensor) paired with the lens, and at the same time, it is beneficial to improve illumination.

[0095] Refractive index is the ratio of the speed of light in a vacuum to the speed of light in a medium. It is mainly used to describe a material's ability to refract light. Different materials have different refractive indices; the higher the refractive index, the slower the light travels in that material. The Abbe number is an index used to represent the dispersion ability of a transparent medium; it can also be called the dispersion coefficient. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion, the larger the Abbe number. Generally speaking, refractive index and Abbe number are inversely proportional. This means that materials with higher refractive indices tend to have lower Abbe numbers, and vice versa.

[0096] Based on the above embodiments, refer to Figure 1 The refractive indices and Abbe numbers of the first lens L1 and the third lens L3 satisfy: 1.73 <Nd1,37.00<Vd1<47.91;1.73<Nd3,15.60<Vd3<25.00。

[0097] Wherein, Nd1 and Nd3 represent the refractive indices of the first lens L1 and the third lens L3, respectively, and Vd1 and Vd3 represent the Abbe numbers of the first lens L1 and the third lens L3, respectively.

[0098] Specifically, when the refractive index and Abbe number of the first lens L1 and the third lens L3 provided in this application embodiment are within this range, it can be ensured that the system can transmit light at a large angle, and the lens aperture meets the structural assembly requirements, while also helping to reduce the size of the lens.

[0099] Based on the above embodiments, refer to Figure 1, the refractive index and Abbe number of the fifth lens L5 satisfy 1.41 < Nd5 < 1.62, 52.00 < Vd5 < 99.8. Here, Nd5 represents the refractive index of the fifth lens L5, and Vd5 represents the Abbe number of the fifth lens L5.

[0100] Specifically, when the refractive index and Abbe number of the fifth lens L5 provided in the embodiments of the present application are within this range, it is beneficial to correct the chromatic aberration of the system and reduce purple fringing, which is helpful for improving the overall image quality of the lens.

[0101] Based on the above embodiments, referring to Figure 1 , the refractive index and Abbe number of the sixth lens L6 and the seventh lens L7 satisfy: 1.42 < Nd6 < 1.75, 48.00 < Vd6 < 98.00; 1.55 < Nd7 < 1.85, 21.00 < Vd7 < 33.00. Here, Nd6 and Nd7 respectively represent the refractive indices of the sixth lens L6 and the seventh lens L7, and Vd6 and Vd7 respectively represent the Abbe numbers of the sixth lens L6 and the seventh lens L7.

[0102] Specifically, when the optical power, refractive index and Abbe number of the sixth lens L6 and the seventh lens L7 provided in the embodiments of the present application are within this range, it is beneficial to reduce the spherical aberration and chromatic aberration of the system, improve the imaging effect, and can reduce light energy loss and increase the imaging brightness.

[0103] Optionally, the sixth lens L6 and the seventh lens L7 are glued together to form a doublet lens. This can effectively reduce the air gap between the sixth lens L6 and the seventh lens L7, reduce the total length of the L-type fish-eye lens, and at the same time help to correct chromatic aberration.

[0104] In summary, by reasonably allocating parameters such as the material, optical power, central thickness of each lens, and the axial spacing between each lens of the present application, the above L-type fish-eye lens system can achieve at least one beneficial effect such as large aperture, high illuminance, ultra-high resolution, and small size.

[0105] Based on the above embodiments, the L-type fish-eye lens may further include a filter CG, which is disposed in the optical path between the eighth lens L8 and the image plane IMA. The filter CG functions to filter light and protect the photosensitive chip in the imaging sensor. Here, the photosensitive chip is used to convert the optical signal collected by the L-type fish-eye lens into an electrical signal, thereby ensuring the imaging effect of the L-type fish-eye lens.

[0106] Referring to Figure 1 As shown, the lenses of the L-type fish-eye lens provided in the embodiments of the present application are arranged in sequence to ensure the stability and clarity of each lens surface and ensure the imaging quality.

[0107] In summary, the L-shaped fisheye lens provided in this embodiment of the invention adopts an optical system structure of 4G1GM3P plus a plane mirror, and by optimizing the optical power of each lens element and the relative position of each lens element, the design of an L-shaped fisheye lens with large aperture, high illumination, ultra-high resolution and small size is finally realized.

[0108] Among them, 4G refers to 4 glass spherical lenses, 1GM refers to 1 glass aspherical lens, and 3P refers to 3 plastic aspherical lenses.

[0109] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the L-shaped fisheye lens applicable to the above-described embodiments.

[0110] Example 1

[0111] Continue to refer to Figure 1 The L-shaped fisheye lens provided in Embodiment 1 of the present invention includes a lens along the optical axis from the object surface ( Figure 1 The image plane IMA is arranged in the following order: first lens L1, second lens L2, third lens L3, plane mirror T, fourth lens L4, aperture stop STO, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, and filter CG. Specifically, first lens L1 is a glass spherical lens with negative optical power; second lens L2 is a plastic aspherical lens with negative optical power; third lens L3 is a glass spherical lens with positive optical power; fourth lens L4 is a plastic aspherical lens with negative optical power; fifth lens L5 is a glass aspherical lens with positive optical power; sixth lens L6 is a glass spherical lens with positive optical power; seventh lens L7 is a glass spherical lens with negative optical power; and eighth lens L8 is a plastic aspherical lens with positive optical power.

[0112] refer to Figure 1 The L-shaped fisheye lens has an effective focal length f of 1.633 mm, an aperture of F# of 1.77, and a field of view of 200°. Table 1 details the specific optical and physical parameters of each lens in the L-shaped fisheye lens provided in Embodiment 1 of the present invention.

[0113] Table 1 Design values ​​of optical physical parameters for L-type fisheye lenses

[0114]

[0115]

[0116] In Table 1, the surface number S is assigned according to the surface sequence of each lens; "OBJ" represents the object plane of the lens; "STO" represents the aperture of an L-shaped fisheye lens; IMA represents the image plane; the radius of curvature R represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "Infinity" indicates that the surface is flat and the radius of curvature is infinite; thickness represents the central axial distance between the current surface and the next surface; refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1. The Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface; a blank space indicates that the current position is air; the more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number. The k value represents the magnitude of the conic coefficient of the aspherical surface.

[0117] In this embodiment of the application, the aspherical lens of the L-shaped fisheye lens satisfies the following formula:

[0118]

[0119] Where z represents the axial sagitta in the Z direction of the aspherical surface; r represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the fitted conic coefficients; A, B, C, D, E, F, and G represent the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial, respectively.

[0120] For example, Table 2 details the aspherical coefficients of each lens in this embodiment one of feasible implementations.

[0121] Table 2 Design values ​​of aspheric coefficients for each lens in an L-type fisheye lens.

[0122]

[0123] Where -8.02097E-05 indicates that the coefficient A of surface number S3 is -8.02097*10 -5 And so on.

[0124] Furthermore, several performance tests were conducted on the L-shaped fisheye lens provided in Embodiment 1, and the specific test results are as follows:

[0125] Figure 2 An axial aberration curve for a fisheye lens is provided in Embodiment 1 of this application, for reference. Figure 2The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of image formation by the L-shaped fisheye lens. Figure 2 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the fisheye lens at each wavelength is well controlled and can meet the requirements of wide spectrum applications.

[0126] Figure 3 This application provides a chromatic aberration curve of a fisheye lens according to Embodiment 1, for reference. Figure 3 The vertical direction represents the normalization of the field of view, with 0 representing the central field of view. The vertical vertex represents the maximum field of view radius, using only the positive field of view angle or height in the Y direction. The horizontal direction represents the distance from the principal ray intercept of each wavelength to the principal ray intercept of the principal wavelength, in micrometers (µm). Different linear curves in the figure represent different wavelengths of the system imaging. Figure 3 It can be seen that the chromatic aberration of the vertical axis at different wavelengths is controlled within the range of (-10um, +10um), indicating that the chromatic aberration of the vertical axis of the fisheye lens at each wavelength is well controlled and can meet the requirements of broadband applications.

[0127] Figure 4 This application provides an illuminance curve diagram of a fisheye lens for Embodiment 1, for reference. Figure 4 The vertical direction represents the illuminance value, normalized to the illumination of the central field of view; the horizontal direction represents the field of view, with units and size consistent with the set field of view units and size. The curves in the figure represent the illuminance values ​​under various fields of view, indicating that the illuminance of the fisheye lens meets the requirements in all fields of view.

[0128] Example 2

[0129] Figure 5 This is a schematic diagram of the structure of a fisheye lens provided in Embodiment 2 of this application, with reference to... Figure 5 Embodiment 2 of this application provides an L-shaped fisheye lens including a lens along the optical axis from the object surface ( Figure 5The image plane IMA is arranged in the following order: first lens L1, second lens L2, third lens L3, plane mirror T, fourth lens L4, aperture stop STO, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, and filter CG. Specifically, first lens L1 is a glass spherical lens with negative optical power; second lens L2 is a plastic aspherical lens with negative optical power; third lens L3 is a glass spherical lens with positive optical power; fourth lens L4 is a plastic aspherical lens with negative optical power; fifth lens L5 is a glass aspherical lens with positive optical power; sixth lens L6 is a glass spherical lens with positive optical power; seventh lens L7 is a glass spherical lens with negative optical power; and eighth lens L8 is a plastic aspherical lens with positive optical power.

[0130] refer to Figure 5 The L-shaped fisheye lens has an effective focal length f of 1.635mm, an aperture of F# of 1.77, and a field of view of 200°. Table 3 details the specific optical and physical parameters of each lens in the L-shaped fisheye lens provided in Embodiment 2 of the present invention.

[0131] Table 3 Design values ​​of optical physical parameters for L-type fisheye lenses

[0132]

[0133]

[0134] In Table 3, the surface number S is assigned according to the surface sequence of each lens; "OBJ" represents the object plane of the lens; "STO" represents the aperture of an L-shaped fisheye lens; IMA represents the image plane; the radius of curvature R represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "Infinity" indicates that the surface is flat and the radius of curvature is infinite; thickness represents the central axial distance between the current surface and the next surface; refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1. The Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface; a blank space indicates that the current position is air; the more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number. The k value represents the magnitude of the conic coefficient of the aspherical surface.

[0135] In this embodiment of the application, the aspherical lens of the L-shaped fisheye lens satisfies the following formula:

[0136]

[0137] Where z represents the axial sagitta in the Z direction of the aspherical surface; r represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the fitted conic coefficients; A, B, C, D, E, F, and G represent the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial, respectively.

[0138] For example, Table 4 details the aspherical coefficients of each lens in Embodiment 2 of this application with a feasible implementation method.

[0139] Table 4. Design values ​​of aspheric coefficients for each lens in an L-type fisheye lens.

[0140]

[0141]

[0142] Where -9.08671E-05 indicates that the coefficient A of surface number S3 is -9.08671E*10. -5 And so on.

[0143] Furthermore, the performance parameters of the L-shaped fisheye lens provided in Example 2 were tested, and the test results are as follows:

[0144] Figure 6 This application provides an axial aberration curve for a fisheye lens in Embodiment 2, for reference. Figure 6 The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of the system's imaging. Figure 6 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the fisheye lens at each wavelength is well controlled and can meet the requirements of wide spectrum applications.

[0145] Figure 7 This application provides a chromatic aberration curve of a fisheye lens according to Embodiment 2, for reference. Figure 7 The vertical direction represents the normalization of the field of view, with 0 representing the central field of view. The vertical vertex represents the maximum field of view radius, using only the positive field of view angle or height in the Y direction. The horizontal direction represents the distance from the principal ray intercept of each wavelength to the principal ray intercept of the principal wavelength, in micrometers (µm). Different linear curves in the figure represent different wavelengths of the system imaging. Figure 7 It can be seen that the chromatic aberration of the vertical axis at different wavelengths is controlled within the range of (-10um, +10um), indicating that the chromatic aberration of the vertical axis of the fisheye lens at each wavelength is well controlled and can meet the requirements of broadband applications.

[0146] Figure 8 This application provides an illuminance curve diagram for a fisheye lens in Embodiment 2, for reference. Figure 8 The vertical direction represents the illuminance value, normalized to the illumination of the central field of view; the horizontal direction represents the field of view, with units and size consistent with the set field of view units and size. The curves in the figure represent the illuminance values ​​under various fields of view, indicating that the illuminance of the fisheye lens meets the requirements in all fields of view.

[0147] Example 3

[0148] Figure 9 This is a schematic diagram of the structure of a fisheye lens provided in Embodiment 3 of this application, with reference to... Figure 9 Embodiment 3 of this application provides an L-shaped fisheye lens including a lens along the optical axis from the object surface ( Figure 9 The image plane IMA is arranged in the following order: first lens L1, second lens L2, third lens L3, plane mirror T, fourth lens L4, aperture stop STO, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, and filter CG. Specifically, first lens L1 is a glass spherical lens with negative optical power; second lens L2 is a plastic aspherical lens with negative optical power; third lens L3 is a glass spherical lens with positive optical power; fourth lens L4 is a plastic aspherical lens with negative optical power; fifth lens L5 is a glass aspherical lens with positive optical power; sixth lens L6 is a glass spherical lens with positive optical power; seventh lens L7 is a glass spherical lens with negative optical power; and eighth lens L8 is a plastic aspherical lens with positive optical power.

[0149] refer to Figure 9 The L-shaped fisheye lens has an effective focal length f of 1.610 mm, an aperture of F# of 1.78, and a field of view of 200°. Table 5 details the specific optical and physical parameters of each lens in the L-shaped fisheye lens provided in Embodiment 3 of the present invention.

[0150] Table 5 Design values ​​of optical physical parameters for L-type fisheye lenses

[0151]

[0152]

[0153] In Table 5, the surface number S is assigned according to the surface sequence of each lens; "OBJ" represents the object plane of the lens; "STO" represents the aperture of an L-shaped fisheye lens; IMA represents the image plane; the radius of curvature R represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "Infinity" indicates that the surface is flat and the radius of curvature is infinite; thickness represents the central axial distance between the current surface and the next surface; refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1. The Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface; a blank space indicates that the current position is air; the more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number. The k value represents the magnitude of the conic coefficient of the aspherical surface.

[0154] In this embodiment of the application, the aspherical lens of the L-shaped fisheye lens satisfies the following formula:

[0155]

[0156] Where z represents the axial sagitta in the Z direction of the aspherical surface; r represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the fitted conic coefficients; A, B, C, D, E, F, and G represent the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial, respectively.

[0157] For example, Table 6 details the aspherical coefficients of each lens in Embodiment 3 of this application with a feasible implementation.

[0158] Table 6 Design values ​​of aspheric coefficients for each lens in an L-type fisheye lens.

[0159]

[0160] Where -8.93688E-05 indicates that the coefficient A of surface number S3 is -8.93688 * 10 -5 And so on.

[0161] Furthermore, the performance parameters of the L-shaped fisheye lens provided in Example 3 were tested, and the test results are as follows:

[0162] Figure 10 This application provides an axial aberration curve for a fisheye lens in Embodiment 3, for reference. Figure 10The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of the system's imaging. Figure 10 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the fisheye lens at each wavelength is well controlled and can meet the requirements of wide spectrum applications.

[0163] Figure 11 This application provides a vertical axis chromatic aberration curve for a fisheye lens in Embodiment 3, for reference. Figure 11 The vertical direction represents the normalization of the field of view, with 0 representing the central field of view. The vertical vertex represents the maximum field of view radius, using only the positive field of view angle or height in the Y direction. The horizontal direction represents the distance from the principal ray intercept of each wavelength to the principal ray intercept of the principal wavelength, in micrometers (µm). Different linear curves in the figure represent different wavelengths of the system imaging. Figure 11 It can be seen that the chromatic aberration of the vertical axis at different wavelengths is controlled within the range of (-10um, +10um), indicating that the chromatic aberration of the vertical axis of the fisheye lens at each wavelength is well controlled and can meet the requirements of broadband applications.

[0164] Figure 12 This application provides an illuminance curve diagram for a fisheye lens in Embodiment 3, for reference. Figure 12 The vertical direction represents the illuminance value, normalized to the illumination of the central field of view; the horizontal direction represents the field of view, with units and size consistent with the set field of view units and size. The curves in the figure represent the illuminance values ​​under various fields of view, indicating that the illuminance of the fisheye lens meets the requirements in all fields of view.

[0165] Example 4

[0166] Figure 13 This is a schematic diagram of the structure of a fisheye lens provided in Embodiment 4 of this application, with reference to... Figure 13 Embodiment 4 of this application provides an L-shaped fisheye lens. The L-shaped fisheye lens includes a lens along the optical axis from the object surface ( Figure 13The image plane IMA is arranged in the following order: first lens L1, second lens L2, third lens L3, plane mirror T, fourth lens L4, aperture stop STO, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, and filter CG. Specifically, first lens L1 is a glass spherical lens with negative optical power; second lens L2 is a plastic aspherical lens with negative optical power; third lens L3 is a glass spherical lens with positive optical power; fourth lens L4 is a plastic aspherical lens with negative optical power; fifth lens L5 is a glass aspherical lens with positive optical power; sixth lens L6 is a glass spherical lens with positive optical power; seventh lens L7 is a glass spherical lens with negative optical power; and eighth lens L8 is a plastic aspherical lens with positive optical power.

[0167] refer to Figure 13 The L-shaped fisheye lens has an effective focal length f of 1.679 mm, an aperture of F# of 1.69, and a field of view of 200°. Table 7 details the specific optical and physical parameters of each lens in the L-shaped fisheye lens provided in Embodiment 4 of the present invention.

[0168] Table 7 Design values ​​of optical physical parameters for L-type fisheye lenses

[0169]

[0170]

[0171] In Table 7, the surface number S is assigned according to the surface sequence of each lens; "OBJ" represents the object plane of the lens; "STO" represents the aperture of an L-shaped fisheye lens; IMA represents the image plane; the radius of curvature R represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "Infinity" indicates that the surface is flat and the radius of curvature is infinite; thickness represents the central axial distance between the current surface and the next surface; refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1. The Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface; a blank space indicates that the current position is air; the more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number. The k value represents the magnitude of the conic coefficient of the aspherical surface.

[0172] In this embodiment of the application, the aspherical lens of the L-shaped fisheye lens satisfies the following formula:

[0173]

[0174] Where z represents the axial sagitta in the Z direction of the aspherical surface; r represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the fitted conic coefficients; A, B, C, D, E, F, and G represent the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial, respectively.

[0175] For example, Table 8 details the aspherical coefficients of each lens in Embodiment 4 of this application with a feasible implementation.

[0176] Table 8 Design values ​​of aspheric coefficients for each lens in an L-type fisheye lens.

[0177]

[0178]

[0179] Where -1.05656E-04 indicates that the coefficient A of surface number S3 is -1.05656 * 10^6. -4 And so on.

[0180] Furthermore, the performance parameters of the L-shaped fisheye lens provided in Example 4 were tested, and the test results are as follows:

[0181] Figure 14 This application provides an axial aberration curve for a fisheye lens in Embodiment 4, for reference. Figure 14 The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of the system's imaging. Figure 14 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the fisheye lens at each wavelength is well controlled and can meet the requirements of wide spectrum applications.

[0182] Figure 15 This application provides a chromatic aberration curve of a fisheye lens according to Embodiment 4, for reference. Figure 15 The vertical direction represents the normalization of the field of view, with 0 representing the central field of view. The vertical vertex represents the maximum field of view radius, using only the positive field of view angle or height in the Y direction. The horizontal direction represents the distance from the principal ray intercept of each wavelength to the principal ray intercept of the principal wavelength, in micrometers (µm). Different linear curves in the figure represent different wavelengths of the system imaging. Figure 15 It can be seen that the chromatic aberration of the vertical axis at different wavelengths is controlled within the range of (-10um, +10um), indicating that the chromatic aberration of the vertical axis of the fisheye lens at each wavelength is well controlled and can meet the requirements of broadband applications.

[0183] Figure 16 This application provides an illuminance curve diagram for a fisheye lens in Embodiment 4, for reference. Figure 16 The vertical direction represents the illuminance value, normalized to the illumination of the central field of view; the horizontal direction represents the field of view, with units and size consistent with the set field of view units and size. The curves in the figure represent the illuminance values ​​under various fields of view, indicating that the illuminance of the fisheye lens meets the requirements in all fields of view.

[0184] In summary, the optical physical parameters of the first lens to the eighth lens in Embodiments 1, 2, 3 and 4 of this application are shown in Table 9.

[0185] Table 9 Design values ​​of optical physical parameters for L-type fisheye lenses

[0186] Scope of protection Example 1 Example 2 Example 3 Example 4 lower limit upper limit Φ1 / Φ -0.14 -0.14 -0.12 -0.19 -0.20 -0.10 Φ2 / Φ -0.24 -0.22 -0.24 -0.17 -0.26 -0.15 Φ3 / Φ 0.10 0.09 0.06 0.10 0.05 0.13 Φ5 / Φ 0.42 0.42 0.44 -0.04 0.36 0.46 Φ6 / Φ 0.31 0.25 0.25 0.38 0.23 0.35 Φ7 / Φ -0.70 -0.59 -0.71 0.33 -0.74 -0.52 Φ8 / Φ 0.24 0.21 0.24 -0.55 0.16 0.30 <![CDATA[T 后组 / T 前组 ]]> 0.70 0.65 0.66 0.17 0.60 0.72 <![CDATA[T 前组 / D1]]> 0.70 0.70 0.66 0.72 0.64 0.73 f*D1 / WFNO 17.59 18.19 18.38 19.46 17.20 19.91 Nd1 1.98 2.01 1.78 2.00 1.73 Nd3 2.10 2.14 1.80 2.08 1.73 Nd5 1.48 1.58 1.58 1.45 1.41 1.62 Nd6 1.62 1.48 1.48 1.69 1.42 1.75 Nd7 1.79 1.65 1.78 1.61 1.55 1.85 Vd1 40.00 41.00 38.46 43.00 37.00 43.91 Vd3 20.47 23.60 20.82 17.00 15.60 25.00 Vd5 68.10 59.00 59.00 93.00 52.00 99.80 Vd6 66.80 90.00 78.56 55.00 48.00 98.00 Vd7 27.90 23.54 22.68 31.00 21.00 33.00

[0187] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An L-shaped fisheye lens, characterized in that, The L-shaped fisheye lens comprises a first lens, a second lens, a third lens, a plane mirror, a fourth lens, an aperture stop, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis from the object plane to the image plane; the number of lenses with optical power in the L-shaped fisheye lens is eight. The first lens is a glass spherical lens with negative optical power, the second lens is a plastic aspherical lens with negative optical power, the third lens is a glass spherical lens with positive optical power, the fourth lens is a plastic aspherical lens with negative optical power, the fifth lens is a glass aspherical lens with positive optical power, the sixth lens is a glass spherical lens with positive optical power, the seventh lens is a glass spherical lens with negative optical power, and the eighth lens is a plastic aspherical lens with positive optical power. The optical power of the first lens to the eighth lens satisfies the following formula: -0.20≤Φ1 / Φ≤-0.10;-0.26≤Φ2 / Φ≤-0.15;0.05≤Φ3 / Φ≤0.13; 0.36≤Φ5 / Φ≤0.46; 0.23≤Φ6 / Φ≤0.35; -0.74≤Φ7 / Φ≤-0.52; 0.16≤Φ8 / Φ≤0.30; Wherein, Φ1, Φ2, Φ3, Φ5, Φ6, Φ7, and Φ8 represent the optical power of the first lens, the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens, respectively, and Φ represents the overall optical power of the L-shaped fisheye lens.

2. The L-shaped fisheye lens according to claim 1, characterized in that, Along the optical axis from the object plane to the image plane, the surface of the lens facing the object plane is called the object-side surface, and the surface of the lens closer to the image plane is called the image-side surface. The object-side surface of the first lens is convex, and the image-side surface is concave. The object-side surface of the second lens is convex, and the image-side surface is concave. The image-side surface of the third lens is convex, and the image-side surface is concave. The object-side surface of the fourth lens is concave, and the image-side surface is convex. The image-side surface of the fifth lens is convex. The object-side surface of the sixth lens is convex, and the image-side surface is also convex. The object-side surface of the seventh lens is concave, and the image-side surface is also concave. The object-side surface of the eighth lens is convex, and the image-side surface is also convex.

3. The L-shaped fisheye lens according to claim 1, characterized in that, The angle between the plane mirror and the optical axis is 45°.

4. The L-shaped fisheye lens according to claim 1, characterized in that, The optical parameters of the L-shaped fisheye lens satisfy: 0.60 <T 后组 / T 前组 <0.72; Among them, T 后组 T is the length along the optical axis from the object surface of the fourth lens to the image surface of the eighth lens. 前组 The length along the optical axis from the object surface of the first lens to the image surface of the third lens is given.

5. The L-shaped fisheye lens according to claim 1, characterized in that, The optical parameters of the L-shaped fisheye lens satisfy: 0.64 ≤ T 前组 / D1 ≤0.73; Among them, T 前组 D1 is the length along the optical axis from the object surface of the first lens to the image surface of the third lens, and D1 is the effective optical diameter of the object surface of the first lens.

6. The L-shaped fisheye lens according to claim 1, characterized in that, The refractive indices and Abbe numbers of the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens satisfy the following: 1.73 <Nd1,37.00<Vd1<47.91;1.73<Nd3,15.60<Vd3<25.00; 1.41 <Nd5<1.62,52.00<Vd5<99.8;1.42<Nd6<1.75,48.00<Vd6<98.00; 1.55 <Nd7<1.85,21.00<Vd7<33.00; Wherein, Nd1, Nd3, Nd5, Nd6, and Nd7 represent the refractive indices of the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens, respectively, and Vd1, Vd3, Vd5, Vd6, and Vd7 represent the Abbe numbers of the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens, respectively.

7. The L-shaped fisheye lens according to claim 1, characterized in that, The sixth lens and the seventh lens are cemented together to form a cemented doublet lens.

8. The L-shaped fisheye lens according to claim 1, characterized in that, It also includes a filter located between the eighth lens and the image plane.

Images