L-shaped fisheye lens

Abstract

The L-shaped fisheye lens 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 which are sequentially arranged from an object plane to an image plane along an optical axis, the first lens is a glass spherical lens with negative focal power, the second lens is a plastic aspheric lens with negative focal power, the third lens is a glass spherical lens with positive focal power, the fourth lens is a plastic aspheric lens with negative focal power, the fifth lens is a glass aspheric lens with positive focal power, and the sixth lens is a glass aspheric 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 aspheric lens with positive focal power. By optimizing the focal power and the relative position of each lens, the design of the L-shaped fisheye lens with large aperture, high illumination, ultrahigh resolution and small volume can be realized, and the market demand of the L-shaped fisheye lens is met.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of optical devices, and in particular to an L-shaped fisheye lens. Background Art

[0002] Fisheye lens is an optical system with a large field of view and a large aperture. Since the fisheye lens can obtain all the optical information in a hemispherical or even super-hemispherical field of view without rotating the fisheye lens, it is widely used in fields such as security monitoring, car driving, unmanned equipment, and sports photography.

[0003] However, the existing general fisheye lenses still have many shortcomings. For example, when the angle is greater than 190°, the edge resolution is generally poor; the edge chromatic aberration is serious and purple fringing is prone to occur; when the aperture is large and the angle is large, the relative illumination of the edge field of view is greatly sacrificed; the overall length of the lens is large, etc., which can no longer meet the increasingly high imaging requirements. Summary of the invention

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

[0005] An embodiment of the present invention provides an L-type fisheye lens, comprising a first lens, a second lens, a third lens, a plane reflector, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence from an object plane to an image plane along an optical axis;

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

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

[0008] Optionally, the optical parameters of the L-type fisheye lens meet:

[0009] 0.60 <T 后组 / T 前组 <0.72;

[0010] Among them, T 后组T is the length on 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 from the object surface of the first lens to the image surface of the third lens on the optical axis.

[0011] Optionally, the optical parameters of the L-type fisheye lens meet:

[0012] 0.64≤T 前组 / D1≤0.73;

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

[0014] Optionally, the optical parameters of the L-type fisheye lens meet:

[0015] 17.20≤f*D1 / WFNO≤19.91;

[0016] Wherein, f is the focal length of the L-type fisheye lens as a whole, D1 is the optical effective diameter of the object surface of the first lens, and WFNO is the working aperture number of the L-type fisheye lens.

[0017] Optionally, the optical power of the first lens to the eighth lens satisfies the following conditional 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] Among them, Φ1, Φ2, Φ3, Φ5, Φ6, Φ7, and Φ8 respectively 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, and Φ represents the overall optical power of the L-type 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:

[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] Among them, 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 are glued together to form a doublet lens.

[0027] Optionally, along the direction from the object plane to the image plane along the optical axis, the surface of the lens facing the object plane is the object side surface, and the surface of the lens close to the image plane is the image side surface;

[0028] The object side surface of the first lens is convex, and the image side surface 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, and the image side surface is convex;

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

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

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

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

[0037] The L-shaped fisheye lens provided by an embodiment of the present invention includes 8 lenses arranged in sequence from the object plane to the image plane along the optical axis. By reasonably matching the optical power combinations of the first lens to the eighth lens into 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 surface and ultra-wide angle is realized, thereby meeting the market demand for L-shaped fisheye lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of an L-shaped fisheye lens provided in Example 1 of the present application;

[0039] Figure 2 An axial aberration curve of an L-type fisheye lens is provided for the first embodiment of the present application;

[0040] Figure 3 A vertical axis chromatic aberration curve diagram of an L-type fisheye lens is provided for Example 1 of the present application;

[0041] Figure 4 An illumination curve diagram of an L-type fisheye lens is provided for the first embodiment of the present application;

[0042] Figure 5 A structural schematic diagram of an L-shaped fisheye lens is provided for the second embodiment of the present application;

[0043] Figure 6 An axial aberration curve of an L-type fisheye lens is provided for the second embodiment of the present application;

[0044] Figure 7 A vertical axis chromatic aberration curve diagram of an L-type fisheye lens is provided for the second embodiment of the present application;

[0045] Figure 8 An illumination curve diagram of an L-type fisheye lens is provided for the second embodiment of the present application;

[0046] Fig. 9 A structural schematic diagram of an L-shaped fisheye lens is provided for the third embodiment of the present application;

[0047] Fig.10 An axial aberration curve of an L-type fisheye lens is provided for the third embodiment of the present application;

[0048] Fig.11 A vertical axis chromatic aberration curve diagram of an L-type fisheye lens is provided for the third embodiment of the present application;

[0049] Fig.12 An illumination curve diagram of an L-type fisheye lens is provided for the third embodiment of the present application;

[0050] Fig.13 A structural schematic diagram of an L-shaped fisheye lens is provided for the fourth embodiment of the present application;

[0051] Fig.14 An axial aberration curve of an L-type fisheye lens is provided for the fourth embodiment of the present application;

[0052] Fig.15 A vertical axis chromatic aberration curve diagram of an L-type fisheye lens is provided for the fourth embodiment of the present application;

[0053] Fig.16An illumination curve diagram of an L-type fisheye lens is provided for Example 4 of the present application. DETAILED DESCRIPTION

[0054] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0055] Figure 1 This is a schematic diagram of the structure of an L-shaped fisheye lens provided in Example 1 of the present application, referring to Figure 1 An L-type fisheye lens provided by an embodiment of the present invention comprises a first lens L1, a second lens L2, a third lens L3, a plane reflector T, a fourth lens L4, an aperture STO, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8 which are arranged in sequence from the object plane to the image plane along the optical axis. Among them, the first lens L1 is a glass spherical lens with negative focal power, the second lens L2 is a plastic aspherical lens with negative focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a plastic aspherical lens with negative focal power, the fifth lens L5 is a glass aspherical lens with positive focal power, the sixth lens L6 is a glass spherical lens with positive focal power, the seventh lens L7 is a glass spherical lens with negative focal power, and the eighth lens L8 is a plastic aspherical lens with positive focal power.

[0056] refer to Figure 1 In the embodiment of the present application, the first lens L1, the second lens L2, the third lens L3, the plane reflector T, the fourth lens L4, the aperture STO, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are arranged in sequence from the object plane to the image plane along the optical axis. It should be noted that, Figure 1 The structural schematic diagrams corresponding to the subsequent embodiments are only schematic diagrams of the structures, and the shapes such as aspherical surfaces are not represented according to the actual situation.

[0057] Among them, the focal length is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam. Its value is the reciprocal of the focal length, which characterizes the ability of the L-type fisheye lens to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be used to characterize a refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a lens, and can also be used to characterize a lens formed by multiple lenses (i.e., a lens group).

[0058] refer to Figure 1The optical power combination of the first lens L1 to the eighth lens L8 provided in the embodiment of the present application satisfies negative, negative, positive, negative, positive, positive, negative and positive. The first lens L1, the second lens L2, and the third lens L3 form a front optical system of the L-type 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 a rear optical system of the L-type fisheye lens.

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

[0060] A plane reflector T is arranged between the third lens L3 and the fourth lens L4. Optionally, the angle between the plane reflector T and the optical axis is 45°, which can also be understood as an inclination angle of 45°, which is used to change the propagation direction of light, which is beneficial to reducing the volume of the L-type fisheye lens.

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

[0062] Considering that glass material is more stable than plastic material in high and low temperature environments, and glass lenses have stronger light turning ability. The present application sets the first lens L1, the third lens L3, the sixth lens L6, and the seventh lens L7 to use glass spherical lenses, and the fifth lens L5 to use glass aspherical lenses, which helps to reduce the number of lenses, reduce the size of the lens, reduce the focus problem caused by thermal effects, and improve the stability of the lens. Considering that aspherical lenses have a good ability to control optical aberrations and optical higher-order aberrations, the second lens L2, the fourth lens L4, and the eighth lens L8 use plastic aspherical lenses, which can reduce the cost of the lens while controlling optical aberrations and optical higher-order 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 the embodiments of the present application will not elaborate on this and will not limit this.

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

[0065]

[0066] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the reciprocal of the radius of curvature; k represents the fitted cone coefficient; 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 aspheric polynomial, respectively.

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

[0068] In the embodiment of the present application, the aperture STO includes an aperture aperture and a field aperture. The aperture aperture refers to the aperture that limits the light beam the most, and the field aperture refers to the aperture that limits the field of view (size) the most. The aperture STO is arranged between the fourth lens L4 with negative focal power and the fifth lens L5 with positive focal power, which is beneficial to limit the entry of stray light at the edge, thereby improving the image quality.

[0069] This application adopts a mixed combination of 4 pieces of spherical glass, 1 piece of aspherical glass and 3 pieces of aspherical plastic, which can correct aberrations well and ensure ultra-high resolution. At the same time, the addition of a plane reflector is conducive to reducing the size of the lens, and has a high cost-effectiveness.

[0070] Optional, reference Figure 1 , along the direction from the object plane to the image plane of the optical axis, the surface of the lens facing the object plane is the object side surface, and the surface of the lens close to the image plane is 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, and the object side surface of the eighth lens L8 is convex, and the image side surface is convex.

[0071] The concave lens has a diverging effect on the transmitted light, and the convex lens has a converging effect on the transmitted light. The present application can achieve clear imaging of the L-type fisheye lens by reasonably setting the surface shapes of the first lens L1 to the eighth lens L8.

[0072] Based on the above embodiments, Figure 1 , the optical parameters of the L-type fisheye lens meet:

[0073] 0.60 <T 后组 / T 前组 <0.72.

[0074] Among them, T 后组is the length on the optical axis from the object surface of the fourth lens L4 to the image surface of the eighth lens L8, T 前组 It is the length on 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 ratio of the lengths of the front optical system and the rear optical system of the L-type fisheye lens provided in the embodiment of the present application is within this range, the lens structure can be made more compact and an installation space can be provided for the plane reflector T between the third lens L3 and the fourth lens L4.

[0076] Based on the above embodiments, Figure 1 , the optical parameters of the L-type fisheye lens meet:

[0077] 0.64≤T 前组 / D1≤0.73.

[0078] Among them, T 前组 is the length on 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 optical effective diameter of the object surface of the first lens L1.

[0079] Among them, the effective aperture in optics refers to the size of the aperture that actually participates in optical imaging or plays an effective role in light propagation in the optical system. It plays a key role in analyzing the performance of the optical system, such as light focusing ability and resolution.

[0080] Specifically, when the optical effective diameter of the front optical system of the L-type fisheye lens provided in the embodiment of the present application and the object-side 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-type fisheye lens and are conducive to the realization of a large angle of the L-type fisheye lens.

[0081] Based on the above embodiments, Figure 1 , the optical parameters of the L-type fisheye lens meet:

[0082] 17.20≤f*D1 / WFNO≤19.91.

[0083] Wherein, f is the focal length of the L-type fisheye lens as a whole, D1 is the optical effective diameter of the object surface of the first lens L1, and WFNO is the working aperture of the L-type fisheye lens.

[0084] Specifically, when the L-type fisheye lens provided in the embodiment of the present application satisfies the above ratio range, it is not only conducive to the realization of a large angle of the L-type fisheye lens, but also conducive to the realization of a large aperture, thereby improving the brightness of the L-type fisheye lens.

[0085] Based on the above embodiments, Figure 1, the optical power of the first lens L1 and the second lens L2 satisfies the following conditional formula: -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-type fisheye lens.

[0086] Specifically, the first lens L1 provided in the embodiment of the present application 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 ensure that the optical system can pass a large angle of light, realizing the design of an L-type fisheye lens.

[0087] Based on the above embodiments, Figure 1 , the focal length of the third lens L3 satisfies the following conditional formula: 0.05≤Φ3 / Φ≤0.13. Wherein, Φ3 represents the focal length of the third lens L3, and Φ represents the focal length of the L-type fisheye lens as a whole.

[0088] Specifically, the third lens L3 provided in the embodiment of the present application is a convex-concave glass spherical lens, and the fourth lens L4 is a concave-convex plastic aspherical lens. When the focal length of the third lens L3 meets this condition, it is beneficial to converge the light of the optical system, thereby facilitating the installation of the plane reflector T, and then through the cooperation of the third lens L3 and the fourth lens L4, it is beneficial to correct the field curvature and aberration of the system.

[0089] Based on the above embodiments, Figure 1 , the power of the fifth lens L5 satisfies the following conditional formula: 0.36≤Φ5 / Φ≤0.46. Wherein Φ5 represents the power of the fifth lens L5, and Φ represents the power of the entire L-type fisheye lens.

[0090] Specifically, the fifth lens L5 provided in the embodiment of the present application is a biconvex glass aspheric lens. When the optical power of the fifth lens L5 is within this range, the light can be further gently contracted at a deflection angle, so that the optical system has a looser tolerance sensitivity, and the use of a glass aspheric surface is conducive to the correction of the system's spherical aberration and coma, which is conducive to improving the resolution of the lens.

[0091] Based on the above embodiments, Figure 1 , the power of the sixth lens L6 and the seventh lens L7 satisfy the following conditional formula: 0.23≤Φ6 / Φ≤0.35; -0.74≤Φ7 / Φ≤-0.52. Wherein, Φ6 represents the power of the sixth lens L6, Φ7 represents the power of the seventh lens L7, and Φ represents the overall power of the L-type fisheye lens.

[0092] Specifically, the sixth lens L6 provided in the embodiment of the present application 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 to correct the aberration of the system.

[0093] Based on the above embodiments, Figure 1 , the optical power of the eighth lens L8 satisfies the following conditional formula: 0.16≤Φ8 / Φ≤0.30. Wherein, Φ8 represents the optical power of the eighth lens L8, and Φ represents the optical power of the entire L-type fisheye lens.

[0094] Specifically, the eighth lens L8 provided in the embodiment of the present application is a biconvex plastic aspheric lens with positive optical power. When the optical power of the eighth lens L8 satisfies this range, it is beneficial to correct the aberrations of the system and to control the angle of the main ray of the system light to match the imaging detector (sensor) matched with the lens, and at the same time it is beneficial to improve the illumination.

[0095] Among them, the refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe the material's ability to refract light. Different materials have different refractive indices. The higher the refractive index, the slower the light propagates in the 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 milder the dispersion of the medium, the larger the Abbe number. Generally speaking, the refractive index and the 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, Figure 1 , the refractive index and Abbe number 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 the embodiment of the present application are within this range, it can be ensured that the system can pass light at a large angle, and the lens aperture meets the structural assembly requirements, while helping to reduce the volume of the lens.

[0099] Based on the above embodiments, Figure 1, the refractive index and Abbe number of the fifth lens L5 satisfy 1.41 < Nd5 < 1.62 and 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 embodiment of the present application are within this range, it is beneficial to correct the chromatic aberration of the system and reduce the purple fringing, which is helpful for improving the overall image quality of the lens.

[0101] On the basis of the above embodiment, 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 indexes 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 embodiment 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 the 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 cemented doublet lens. It 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 contribute to achromatism.

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

[0105] On the basis of the above embodiment, the L-type fish-eye lens may further include a filter CG, which is arranged in the optical path between the eighth lens L8 and the image plane IMA. The filter CG plays a role in filtering light and protecting 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 embodiment 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-type fisheye lens provided in the embodiment of the present invention adopts an optical system structure of 4G1GM3P plus a plane reflector, and by optimizing the optical focal length of each lens element and the relative position of each lens element, ultimately realizes the design of an L-type fisheye lens with large aperture, high illumination, ultra-high resolution and small size.

[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] A specific embodiment of the L-type fisheye lens applicable to the above-mentioned embodiment will be further described below with reference to the accompanying drawings.

[0110] Embodiment 1

[0111] Continue to refer Figure 1 The first embodiment of the present invention provides an L-type fisheye lens including a lens extending from the object plane ( Figure 1 The first lens L1, the second lens L2, the third lens L3, the plane reflector T, the fourth lens L4, the aperture STO, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8 and the filter CG are arranged in sequence from the image plane IMA (not shown in the figure). Among them, the first lens L1 is a glass spherical lens with negative focal power, the second lens L2 is a plastic aspherical lens with negative focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a plastic aspherical lens with negative focal power, the fifth lens L5 is a glass aspherical lens with positive focal power, the sixth lens L6 is a glass spherical lens with positive focal power, the seventh lens L7 is a glass spherical lens with negative focal power, and the eighth lens L8 is a plastic aspherical lens with positive focal power.

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

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

[0114]

[0115]

[0116] Among them, the surface number S in Table 1 is numbered according to the order of the surfaces of each lens; "OBJ" represents the object surface of the lens; "STO" represents the aperture of the L-type fisheye lens; IMA represents the image surface; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "Infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, and the blank represents 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 to the light; the blank represents that the current position is air; the more severe the dispersion of the medium, the smaller the Abbe number; conversely, the milder the dispersion of the medium, the larger the Abbe number. The k value represents the numerical value of the conic coefficient of the aspheric surface.

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

[0118]

[0119] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the reciprocal of the radius of curvature; k represents the fitted cone coefficient; 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 aspheric polynomial, respectively.

[0120] Exemplarily, Table 2 describes in detail the aspheric coefficients of each lens in the first embodiment in a feasible implementation manner.

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

[0122]

[0123] Among them, -8.02097E-05 means that the coefficient A of the surface number S3 is -8.02097*10 -5 , and so on.

[0124] Furthermore, a number of performance tests were conducted on the L-type fisheye lens provided in Example 1, and the test results are as follows:

[0125] Figure 2 An axial aberration curve of a fisheye lens is provided for the first embodiment of the present application, with reference to Figure 2, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of L-type fisheye lens imaging, 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 needs of wide spectrum applications.

[0126] Figure 3 A vertical axis chromatic aberration curve of a fisheye lens is provided for the first embodiment of the present application. Figure 3 , the vertical direction represents the normalization of the field of view, 0 represents the central field of view, the vertical vertex represents the maximum field of view radius, and only the positive field of view angle or height in the Y direction is used; the horizontal direction represents the distance from the main ray intercept of each wavelength to the main wavelength main ray intercept, in micrometers (um). The different linear curves in the figure represent different wavelengths of imaging of the system, which are represented by Figure 3 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within the range of (-10um, +10um), indicating that the vertical chromatic aberration of the fisheye lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0127] Figure 4 A fisheye lens illumination curve diagram is provided for the first embodiment of the present application, referring to Figure 4 , the vertical direction represents the illumination value, which is normalized by the illumination of the central field of view; the horizontal direction represents the field of view, and the unit and size are consistent with the set field of view unit and size. The curve in the figure represents the illumination value under each field of view, indicating that the illumination of the fisheye lens in each field of view meets the requirements.

[0128] Embodiment 2

[0129] Figure 5 A structural diagram of a fisheye lens is provided for the second embodiment of the present application, referring to Figure 5 , Embodiment 2 of the present application provides an L-type fisheye lens including: Figure 5The first lens L1, the second lens L2, the third lens L3, the plane reflector T, the fourth lens L4, the aperture STO, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8 and the filter CG are arranged in sequence from the image plane IMA (not shown in the figure). Among them, the first lens L1 is a glass spherical lens with negative focal power, the second lens L2 is a plastic aspherical lens with negative focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a plastic aspherical lens with negative focal power, the fifth lens L5 is a glass aspherical lens with positive focal power, the sixth lens L6 is a glass spherical lens with positive focal power, the seventh lens L7 is a glass spherical lens with negative focal power, and the eighth lens L8 is a plastic aspherical lens with positive focal power.

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

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

[0132]

[0133]

[0134] Among them, the surface number S in Table 3 is numbered according to the surface order of each lens; "OBJ" represents the object surface of the lens; "STO" represents the aperture of the L-type fisheye lens; IMA represents the image surface; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "Infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, and the blank represents 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 to the light; the blank represents that the current position is air; the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number. The k value represents the numerical value of the conic coefficient of the aspheric surface.

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

[0136]

[0137] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the reciprocal of the radius of curvature; k represents the fitted cone coefficient; 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 aspheric polynomial, respectively.

[0138] Exemplarily, Table 4 describes in detail the aspheric coefficients of each lens in Example 2 of the present application in a feasible implementation manner.

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

[0140]

[0141]

[0142] Among them, -9.08671E-05 means that the coefficient A of the surface number S3 is -9.08671E*10 -5 , and so on.

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

[0144] Figure 6 A fisheye lens axial aberration curve is provided for the second embodiment of the present application, referring to Figure 6 , the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging in the system, 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 needs of wide spectrum applications.

[0145] Figure 7 A vertical axis chromatic aberration curve of a fisheye lens is provided for the second embodiment of the present application, referring to Figure 7 , the vertical direction represents the normalization of the field of view, 0 represents the central field of view, the vertical vertex represents the maximum field of view radius, and only the positive field of view angle or height in the Y direction is used; the horizontal direction represents the distance from the main ray intercept of each wavelength to the main wavelength main ray intercept, in micrometers (um). The different linear curves in the figure represent different wavelengths of imaging of the system, which are represented by Figure 7 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within the range of (-10um, +10um), indicating that the vertical chromatic aberration of the fisheye lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0146] Figure 8 A fisheye lens illumination curve diagram is provided for the second embodiment of the present application, referring to Figure 8 , the vertical direction represents the illumination value, which is normalized by the illumination of the central field of view; the horizontal direction represents the field of view, and the unit and size are consistent with the set field of view unit and size. The curve in the figure represents the illumination value under each field of view, indicating that the illumination of the fisheye lens in each field of view meets the requirements.

[0147] Embodiment 3

[0148] Fig. 9 A structural diagram of a fisheye lens is provided for the third embodiment of the present application, referring to Fig. 9 Embodiment 3 of the present application provides an L-type fisheye lens including a Fig. 9 The first lens L1, the second lens L2, the third lens L3, the plane reflector T, the fourth lens L4, the aperture STO, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8 and the filter CG are arranged in sequence from the image plane IMA (not shown in the figure). Among them, the first lens L1 is a glass spherical lens with negative focal power, the second lens L2 is a plastic aspherical lens with negative focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a plastic aspherical lens with negative focal power, the fifth lens L5 is a glass aspherical lens with positive focal power, the sixth lens L6 is a glass spherical lens with positive focal power, the seventh lens L7 is a glass spherical lens with negative focal power, and the eighth lens L8 is a plastic aspherical lens with positive focal power.

[0149] refer to Fig. 9 The effective focal length f of the L-type fisheye lens is 1.610 mm, the aperture F# is 1.78, and the field angle is 200°. Table 5 details the specific optical and physical parameters of each lens in the L-type fisheye lens provided in the third embodiment of the present invention.

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

[0151]

[0152]

[0153] Among them, the surface number S in Table 5 is numbered according to the order of the surfaces of each lens; "OBJ" represents the object surface of the lens; "STO" represents the aperture of the L-type fisheye lens; IMA represents the image surface; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "Infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, and the blank represents 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 to the light; the blank represents that the current position is air; the more severe the dispersion of the medium, the smaller the Abbe number; conversely, the milder the dispersion of the medium, the larger the Abbe number. The k value represents the numerical value of the conic coefficient of the aspheric surface.

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

[0155]

[0156] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the reciprocal of the radius of curvature; k represents the fitted cone coefficient; 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 aspheric polynomial, respectively.

[0157] Exemplarily, Table 6 describes in detail the aspheric coefficients of each lens in Example 3 of the present application in a feasible implementation manner.

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

[0159]

[0160] Among them, -8.93688E-05 means that the coefficient A of the surface number S3 is -8.93688*10 -5 , and so on.

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

[0162] Fig.10 A fisheye lens axial aberration curve is provided for the third embodiment of the present application, referring to Fig.10, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging in the system, Fig.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 needs of wide spectrum applications.

[0163] Fig.11 A vertical axis chromatic aberration curve diagram of a fisheye lens is provided for the third embodiment of the present application, referring to Fig.11 , the vertical direction represents the normalization of the field of view, 0 represents the central field of view, the vertical vertex represents the maximum field of view radius, and only the positive field of view angle or height in the Y direction is used; the horizontal direction represents the distance from the main ray intercept of each wavelength to the main wavelength main ray intercept, in micrometers (um). The different linear curves in the figure represent different wavelengths of imaging of the system, which are represented by Fig.11 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within the range of (-10um, +10um), indicating that the vertical chromatic aberration of the fisheye lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0164] Fig.12 A fisheye lens illumination curve diagram is provided for the third embodiment of the present application, referring to Fig.12 , the vertical direction represents the illumination value, which is normalized by the illumination of the central field of view; the horizontal direction represents the field of view, and the unit and size are consistent with the set field of view unit and size. The curve in the figure represents the illumination value under each field of view, indicating that the illumination of the fisheye lens in each field of view meets the requirements.

[0165] Embodiment 4

[0166] Fig.13 A structural schematic diagram of a fisheye lens is provided for the fourth embodiment of the present application, referring to Fig.13 Embodiment 4 of the present application provides an L-type fisheye lens. The L-type fisheye lens includes a Fig.13The first lens L1, the second lens L2, the third lens L3, the plane reflector T, the fourth lens L4, the aperture STO, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8 and the filter CG are arranged in sequence from the image plane IMA (not shown in the figure). Among them, the first lens L1 is a glass spherical lens with negative focal power, the second lens L2 is a plastic aspherical lens with negative focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a plastic aspherical lens with negative focal power, the fifth lens L5 is a glass aspherical lens with positive focal power, the sixth lens L6 is a glass spherical lens with positive focal power, the seventh lens L7 is a glass spherical lens with negative focal power, and the eighth lens L8 is a plastic aspherical lens with positive focal power.

[0167] refer to Fig.13 The effective focal length f of the L-type fisheye lens is 1.679 mm, the aperture F# is 1.69, and the field angle is 200°. Table 7 details the specific optical and physical parameters of each lens in the L-type fisheye lens provided in the fourth embodiment of the present invention.

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

[0169]

[0170]

[0171] Among them, the surface number S in Table 7 is numbered according to the order of the surfaces of each lens; "OBJ" represents the object surface of the lens; "STO" represents the aperture of the L-type fisheye lens; IMA represents the image surface; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "Infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, and the blank represents 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 to the light; the blank represents that the current position is air; the more severe the dispersion of the medium, the smaller the Abbe number; conversely, the milder the dispersion of the medium, the larger the Abbe number. The k value represents the numerical value of the conic coefficient of the aspheric surface.

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

[0173]

[0174] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the reciprocal of the radius of curvature; k represents the fitted cone coefficient; 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 aspheric polynomial, respectively.

[0175] Exemplarily, Table 8 describes in detail the aspheric coefficients of each lens in Example 4 of the present application in a feasible implementation manner.

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

[0177]

[0178]

[0179] Among them, -1.05656E-04 means that the coefficient A of the surface number S3 is -1.05656*10 -4 , and so on.

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

[0181] Fig.14 A fisheye lens axial aberration curve is provided for the fourth embodiment of the present application, referring to Fig.14 , the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of imaging in the system, Fig.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 needs of wide spectrum applications.

[0182] Fig.15 A vertical axis chromatic aberration curve diagram of a fisheye lens is provided for Example 4 of the present application, with reference to Fig.15 , the vertical direction represents the normalization of the field of view, 0 represents the central field of view, the vertical vertex represents the maximum field of view radius, and only the positive field of view angle or height in the Y direction is used; the horizontal direction represents the distance from the main ray intercept of each wavelength to the main wavelength main ray intercept, in micrometers (um). The different linear curves in the figure represent different wavelengths of imaging of the system, which are represented by Fig.15 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within the range of (-10um, +10um), indicating that the vertical chromatic aberration of the fisheye lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0183] Fig.16 A fisheye lens illumination curve diagram is provided for the fourth embodiment of the present application, referring to Fig.16 , the vertical direction represents the illumination value, which is normalized by the illumination of the central field of view; the horizontal direction represents the field of view, and the unit and size are consistent with the set field of view unit and size. The curve in the figure represents the illumination value under each field of view, indicating that the illumination of the fisheye lens in each field of view meets the requirements.

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

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

[0186] Scope of protection Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 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 are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An L-type fisheye lens, characterized in that: It includes a first lens, a second lens, a third lens, a plane reflector, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are arranged in sequence from the object plane to the image plane along the optical axis; 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.

2. The L-shaped fisheye lens according to claim 1, characterized in that: Along the direction from the object plane to the image plane along the optical axis, the surface of the lens facing the object plane is the object side surface, and the surface of the lens close to the image plane is 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 a convex surface, and the image side surface is a convex surface; The object side surface of the sixth lens is convex, and the image side surface is convex; The object side surface of the seventh lens is concave, and the image side surface is concave; The object-side surface of the eighth lens is convex, and the image-side surface is convex.

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

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

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

6. The L-type fisheye lens according to claim 1, characterized in that: The optical parameters of the L-type fisheye lens satisfy: 17.20≤f*D1 / WFNO≤19.91; Wherein, f is the focal length of the L-type fisheye lens as a whole, D1 is the optical effective diameter of the object surface of the first lens, and WFNO is the working aperture number of the L-type fisheye lens.

7. The L-type fisheye lens according to claim 1, characterized in that: The optical power of the first lens to the eighth lens satisfies the following conditional 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; Among them, Φ1, Φ2, Φ3, Φ5, Φ6, Φ7, and Φ8 respectively 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, and Φ represents the overall optical power of the L-type fisheye lens.

8. The L-type fisheye lens according to claim 1, characterized in that: The refractive index and Abbe number of the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens satisfy: 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; Among them, 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.

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

10. The L-type fisheye lens according to claim 1, characterized in that: It also includes a filter, which is located between the eighth lens and the image plane.

Images