Optical lens and imaging device

Abstract

The invention provides an optical lens and an imaging device, and belongs to the technical field of optical imaging. The optical lens comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power which are sequentially arranged from the object side to the image side. The optical lens comprises an eighth lens with positive focal power and an image plane, so that the horizontal field angle of the optical lens reaches over 126 degrees, the aperture value is less than or equal to 2.0, and the height of the image plane reaches 6.6 mm. Wherein the second lens, the third lens, the seventh lens and the eighth lens are plastic aspheric lenses, and the other lenses are spherical lenses. According to the scheme, the eight lenses are adopted, and the focal power and the shape matching relation of each lens are reasonably set, so that the optical lens which is small in size, high in resolution, low in cost and free of virtual focus at high temperature is realized.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to an optical lens and an imaging device. Background Art

[0002] With the development of science and technology, the structures of various components are becoming more and more complex, and consumers' requirements are getting higher and higher. Lens products need to have the advantages of shooting a wide frame, and at the same time, they need to meet the high and low temperature requirements of the lens. At present, there are common problems that cannot take into account a wide viewing angle, low cost, high pixel, no blur at high and low temperatures, and good night vision effects. For example, some lenses sacrifice part of the resolution or use plastic aspherical surfaces to reduce costs, but due to the large temperature difference in the actual environment, such lenses are often prone to blur due to high and low temperatures, affecting the use effect; while some lenses have good night vision effects and high imaging quality, but they are expensive and are not recognized by the consumer market. Summary of the invention

[0003] The main purpose of the present invention is to provide an optical lens and an imaging device, aiming to provide an optical lens with a large viewing angle, low cost, no defocusing at high and low temperatures, and good infrared confocal effect.

[0004] To achieve the above object, the present invention provides an optical lens, the optical lens having an object side and an image side arranged opposite to each other along an optical axis direction, the optical lens comprising a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with positive optical power and an image plane, which are arranged in sequence from the object side to the image side, so that the horizontal field angle of the optical lens reaches 126°, the aperture value is less than or equal to 2.0, and the image plane height reaches 6.6 mm;

[0005] Among them, the second lens, the third lens, the seventh lens and the eighth lens are plastic aspherical lenses, and the first lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses.

[0006] In one embodiment, the optical lens further includes an aperture stop, and the aperture stop is disposed between the fourth lens and the fifth lens.

[0007] In one embodiment, the optical lens further includes a filter and a protective glass which are sequentially arranged between the eighth lens and the image plane from the object side to the image side.

[0008] In one implementation, the fifth lens and the sixth lens are cemented together.

[0009] In one embodiment, the first lens is a meniscus lens, and its object-side surface is a convex surface;

[0010] The second lens is a concave-convex lens, and its object side surface is convex;

[0011] The third lens is a biconcave lens;

[0012] The fourth lens is a biconvex lens;

[0013] The fifth lens is a biconvex lens;

[0014] The sixth lens is a biconcave lens;

[0015] The seventh lens is a biconvex lens;

[0016] The eighth lens is a biconvex lens.

[0017] In one embodiment, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is 7, and the focal length of the eighth lens is f8, wherein:

[0018] -15<f1<-8, -15<f2<-8, -8<f3<-4, 4<f4<9, 3<f5<8, -6<f6<-2, 4<f7<10, 10<f8<25.

[0019] In one embodiment, the refractive index of the first lens is n1, and the dispersion coefficient is v1; the refractive index of the second lens is n2, and the dispersion coefficient is v2; the refractive index of the third lens is n3, and the dispersion coefficient is v3; the focal refractive index of the fourth lens is n4, and the dispersion coefficient is v4; the refractive index of the fifth lens is n5, and the dispersion coefficient is v5; the refractive index of the sixth lens is n6, and the dispersion coefficient is v6; the refractive index of the seventh lens is n7, and the dispersion coefficient is v7; the refractive index of the eighth lens is n8, and the dispersion coefficient is v8, wherein:

[0020] 1.55≤n1≤1.75, 1.50≤n2≤1.60, 1.50≤n3≤1.60, 1.75≤n4≤1.95, 1.50≤n5≤1.70, 1.70≤n6≤1.95, 1.50≤n7≤1.60, 1.50≤n8≤1.70, 45.0≤v1≤75.0, 50.0≤v2≤65.0, 50.0≤v3≤65.0, 25.0≤v4≤45.0, 50.0≤v5≤75.0, 25.0≤v6≤35.0, 50.0≤v7≤65.0, 50.0≤v8≤65.0.

[0021] In one embodiment, the effective focal length of the optical lens is EFL, and the total optical length of the optical lens is TTL, wherein:

[0022] TTL / EFL≤10.5.

[0023] In one embodiment, the diameter of the first lens is D1, and the image diameter of the optical lens is IC, wherein:

[0024] D1<15mm, IC≤6.6mm.

[0025] The present invention further provides an imaging device, comprising the above-mentioned optical lens, wherein the optical lens has an object side and an image side which are arranged opposite to each other along the optical axis direction, and the optical lens comprises a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with positive optical power and an image plane which are arranged in sequence from the object side to the image side, so that the horizontal field angle of the optical lens reaches 126°, the aperture value is less than or equal to 2.0, and the image plane height reaches 6.6 mm;

[0026] Among them, the second lens, the third lens, the seventh lens and the eighth lens are plastic aspherical lenses, and the first lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses.

[0027] The technical solution provided by the present invention is conducive to the collection of light in the optical system by setting the first lens with negative focal power, which can effectively increase the field of view; by setting the fourth lens with positive focal power, it bears the larger focal power of the system, changes the propagation direction of the light beam, corrects the aberration of the off-axis field of view, and is more conducive to the imaging of the light beam on the image plane; by setting the second lens, the third lens, the seventh lens and the eighth lens as plastic aspheric lenses, the use ratio of glass lenses is reduced, the cost is reduced, and various aberrations are corrected, the edge image quality is improved, and the imaging quality is high. Among them, the plastic lens materials are all low-refractive index materials with good processability, stable molding, low sensitivity and high yield. By setting other lenses as spherical lenses, the aberration is effectively improved, ensuring that it does not defocus under high and low temperature conditions; the light trend of the lens is smooth, while introducing more light, the structure is more compact, and the total optical length is controlled within 25mm. In terms of aperture, the aperture value F satisfies F≤2.0, the image plane height can reach φ6.6mm, and the lens can also clearly image in weak light. By properly setting the focal length ratio, the optical system has good athermalization, more stable working performance, and a horizontal field of view of more than 126°, CRA≤12°, which can match a variety of sensors and has broad application prospects. By using eight lenses and properly setting the focal length and shape matching relationship of each lens, an optical lens with good performance such as large viewing angle, high pixel, good infrared confocal effect, high yield, excellent manufacturability, and good athermalization is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 A schematic structural diagram of an embodiment of an optical lens provided by the present invention;

[0030] Figure 2 for Figure 1 Schematic diagram of vertical axis chromatic aberration curve of medium optical lens;

[0031] Figure 3 for Figure 1 Light fan diagram of medium optical lens;

[0032] Figure 4 for Figure 1 Schematic diagram of field curvature distortion of optical lens;

[0033] Figure 5 for Figure 1 MTF curve of medium optical lens at 20℃;

[0034] Figure 6 for Figure 1 The defocus MTF curve of the medium optical lens in the visible light band at 20℃;

[0035] Figure 7 for Figure 1 The defocus MTF curve of the medium optical lens in the infrared band at 20℃;

[0036] Figure 8 for Figure 1 The defocus MTF curve of the medium optical lens in the visible light band at -30℃;

[0037] Fig. 9 for Figure 1 Through-focus MTF curve of the medium optical lens in the visible light band at 85°C.

[0038] Description of Figure Numbers:

[0039] 1000. Optical lens; 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; a. Aperture; b. Filter; c. Protective glass; d. Image plane.

[0040] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0043] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0044] With the development of science and technology, the structures of various components are becoming more and more complex, and consumers' requirements are getting higher and higher. Lens products need to have the advantages of shooting a wide frame, and at the same time, they need to meet the high and low temperature requirements of the lens. At present, there are common problems that cannot take into account a wide viewing angle, low cost, high pixel, no blur at high and low temperatures, and good night vision effects. For example, some lenses sacrifice part of the resolution or use plastic aspherical surfaces to reduce costs, but due to the high heat generated by the projector, such lenses are often prone to blur due to high and low temperatures, affecting the use effect; while some lenses have good night vision effects and high imaging quality, but they are expensive and are not recognized by the consumer market.

[0045] The main purpose of the present invention is to provide an optical lens and an imaging device, aiming to provide an optical lens with a large viewing angle, low cost, no defocusing at high and low temperatures, and good infrared confocal effect.

[0046] See also Figure 1 The present invention provides an optical lens 1000, wherein the optical lens 1000 has an object side and an image side which are arranged opposite to each other along the optical axis direction, and the optical lens 1000 comprises a first lens 1 with negative optical focal length, a second lens 2 with negative optical focal length, a third lens 3 with negative optical focal length, a fourth lens 4 with positive optical focal length, a fifth lens 5 with positive optical focal length, a sixth lens 6 with negative optical focal length, a seventh lens 7 with positive optical focal length, an eighth lens 8 with positive optical focal length and an image plane d which are arranged in sequence from the object side to the image side, so that the horizontal field angle of the optical lens 1000 reaches above 126°, the aperture value is less than or equal to 2.0, and the height of the image plane d reaches 6.6 mm; wherein the second lens 2, the third lens 3, the seventh lens 7 and the eighth lens 8 are plastic aspherical lenses, and the first lens 1, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are spherical lenses.

[0047] The technical solution provided by the present invention is conducive to the collection of light in the optical system by setting the first lens 1 with negative focal power, which can effectively increase the field of view; by setting the fourth lens 4 with positive focal power, it bears the larger focal power of the system, changes the propagation direction of the light beam, corrects the aberration of the off-axis field of view, and is more conducive to the imaging of the light beam on the image plane; by setting the second lens 2, the third lens 3, the seventh lens 7 and the eighth lens 8 as plastic aspheric lenses, the proportion of glass lenses used is reduced, the cost is reduced, and various aberrations are corrected, the edge image quality is improved, and the imaging quality is high. Among them, the plastic lens materials are all low-refractive index materials with good processability, stable molding, low sensitivity and high yield. By setting other lenses as spherical lenses, the aberration is effectively improved, ensuring that it does not defocus under high and low temperature conditions; the light trend of the lens is smooth, while introducing more light, the structure is more compact, and the total optical length is controlled within 25mm. In terms of aperture, the aperture value F satisfies F≤2.0, the image plane height can reach φ6.6mm, and the lens can also clearly image in weak light. By properly setting the focal length ratio, the optical system has good athermalization, more stable working performance, and a horizontal field of view of more than 126°, CRA ≤ 12°, which can match a variety of sensors and has broad application prospects. By using eight lenses and properly setting the focal length and shape matching relationship of each lens, the optical lens 1000 with good performance such as large viewing angle, high pixel, good infrared confocal effect, high yield, excellent manufacturability and good athermalization is achieved.

[0048] It should be noted that the characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens, which is different from a spherical lens that has a constant curvature from the center of the lens to the periphery of the lens.

[0049] Furthermore, the optical lens 1000 further includes an aperture a, which is disposed between the fourth lens 4 and the fifth lens 5. The aperture a limits the aperture of the light beam on the optical axis, intercepts part of the light, thereby reducing the light spot, improving the image contrast, and also expanding the target surface and improving the image quality. According to actual conditions, adjusting the light flux of the aperture a helps to further improve the imaging quality.

[0050] Furthermore, the optical lens 1000 also includes a filter b and a protective glass c which are sequentially arranged between the eighth lens 8 and the image plane d from the object side to the image side. The filter b is used to filter out stray light in non-working bands to reduce optical noise and reduce difficulties for the subsequent photoelectric module processing part. The filter b can also be used to adjust the color of the object image during the final imaging. The protective glass c can play the role of waterproofing, dustproofing, and protecting the lens, thereby enhancing the anti-interference ability of the lens and improving the imaging quality.

[0051] Furthermore, in order to improve the image quality of the optical system, reduce the loss of light energy, increase the image clarity, protect the scale surface, and further optimize the processing flow to meet the design requirements, the fifth lens 5 and the sixth lens 6 are glued together. In this way, the glued parts are used reasonably and the optical power is reasonably distributed, which can well correct the aberration and achieve the effect of high temperature athermalization. It also effectively reduces chromatic aberration and improves the clarity of imaging.

[0052] Specifically, in a preferred embodiment, please refer to Figure 1 The first lens 1 is a concave-convex lens, and its object-side surface is convex; the second lens 2 is a concave-convex lens, and its object-side surface is convex; the third lens 3 is a biconcave lens; the fourth lens 4 is a biconvex lens; the fifth lens 5 is a biconvex lens; the sixth lens 6 is a biconcave lens; the seventh lens 7 is a biconvex lens; and the eighth lens 8 is a biconvex lens.

[0053] Further, the focal length of the first lens 1 is f1, the focal length of the second lens 2 is f2, the focal length of the third lens 3 is f3, the focal length of the fourth lens 4 is f4, the focal length of the fifth lens 5 is f5, the focal length of the sixth lens 6 is f6, the focal length of the seventh lens 7 is 7, and the focal length of the eighth lens 8 is f8, wherein: -15<f1<-8, -15<f2<-8, -8<f3<-4, 4<f4<9, 3<f5<8, -6<f6<-2, 4<f7<10, 10<f8<25. This embodiment is a preferred embodiment, and through the mutual combination of different lenses and the reasonable allocation of their optical focal lengths, the entire lens has good performance such as low cost and high pixel.

[0054] Further, the refractive index of the first lens 1 is n1, and the dispersion coefficient is v1, the refractive index of the second lens 2 is n2, and the dispersion coefficient is v2, the refractive index of the third lens 3 is n3, and the dispersion coefficient is v3, the focal refractive index of the fourth lens 4 is n4, and the dispersion coefficient is v4, the refractive index of the fifth lens 5 is n5, and the dispersion coefficient is v5, the refractive index of the sixth lens 6 is n6, and the dispersion coefficient is v6, the refractive index of the seventh lens 7 is n7, and the dispersion coefficient is v7, the refractive index of the eighth lens 8 is n8, and the dispersion coefficient is v8, wherein: 1.55≤n1 ≤1.75, 1.50≤n2≤1.60, 1.50≤n3≤1.60, 1.75≤n4≤1.95, 1.50≤n5≤1.70, 1.70≤n6≤1.95, 1.50≤n7≤1.60, 1.50≤n8≤1.70, 45.0≤v1≤75.0, 50.0≤v2≤65.0, 50.0≤v3≤65.0, 25.0≤v4≤45.0, 50.0≤v5≤75.0, 25.0≤v6≤35.0, 50.0≤v7≤65.0, 50.0≤v8≤65.0. This embodiment is a preferred embodiment. By combining different lenses and reasonably allocating their refractive indices and dispersion coefficients, the optical lens 1000 has the performances of low cost, high pixel count, and good athermal performance.

[0055] In one embodiment provided by the present invention, the effective focal length of the optical lens 1000 is EFL, and the total optical length of the optical lens 1000 is TTL, wherein: TTL / EFL≤10.5. By reasonably limiting the size of the EFL, the size of the total optical length can be further limited, making the entire optical system more compact, which helps to control the focal length of the optical lens 1000.

[0056] In one embodiment provided by the present invention, the total optical length of the optical lens 1000 is TTL, the diameter of the first lens 1 is D1, and the image plane diameter of the optical lens 1000 is IC, wherein: D1 < 15 mm, IC ≤ 6.6 mm. With such a design, by limiting the numerical relationship of the above optical system characteristics, it is possible to avoid the optical lens 1000 from being too large in diameter to meet the installation space requirements of the final product, and by limiting the specific values ​​of the total optical length and the diameter of the first lens 1, the lens size can be appropriately limited, which helps to achieve miniaturization of the lens.

[0057] It is worth mentioning that the surface shape of the aspherical lens in the optical lens 1000 in this embodiment should satisfy the following equation:

[0058]

[0059] Among them, c is the curvature corresponding to the radius; y is the radial coordinate (its unit is the same as the lens length unit); k is the conic coefficient, and A, B, C, D, E, F... respectively represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order... aspheric coefficients. The above parameters can be used to set the shape and size of the aspheric surface of the lens facing the object side and the image side.

[0060] Among them, when k<-1, the corresponding surface curve of the lens is a hyperbola; when k=-1, the corresponding surface curve of the lens is a parabola; when -1<k<0, the corresponding surface curve of the lens is an ellipse; when k=0, the corresponding surface curve of the lens is a circle; when k>0, the corresponding surface curve of the lens is an oblate circle.

[0061] It should be noted that the basic parameter table of the optical lens 1000 in an embodiment provided by the present invention is shown in Table 1, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0062] Table 1

[0063]

[0064]

[0065] In this embodiment, the aspheric coefficients of the aspheric lens in the optical lens 1000 include: the quadratic surface coefficient k, the fourth-order aspheric coefficient A, the sixth-order aspheric coefficient B, the eighth-order aspheric coefficient C, the tenth-order aspheric coefficient D, the twelfth-order aspheric coefficient E, and the fourteenth-order aspheric coefficient F of the surface, as shown in Table 2 below.

[0066] Table 2

[0067] Face number k A B C D E F 3 -85.091 1.50E-03 6.30E-05 -3.11E-06 8.88E-08 -1.45E-09 2.47E-11 4 -1.490 9.24E-04 4.54E-04 1.63E-06 -5.26E-07 9.12E-08 1.82E-09 5 -1.242 6.35E-03 -7.41E-04 5.49E-05 -2.01E-06 0.00E+00 0.00E+00 6 0.000 1.01E-02 -7.79E-04 6.22E-05 -2.28E-06 0.00E+00 0.00E+00 13 0.028 5.28E-04 -2.13E-04 2.21E-05 -9.68E-07 -1.05E-07 1.47E-08 14 -2.061 -1.88E-03 2.15E-04 -6.18E-06 -3.09E-07 0.00E+00 0.00E+00 15 -98.210 -3.39E-03 -2.11E-04 1.87E-05 -2.56E-08 0.00E+00 0.00E+00 16 35.941 -4.52E-03 9.56E-05 -2.73E-06 5.77E-07 0.00E+00 0.00E+00

[0068] Please refer to Figure 2 , is a schematic diagram of the vertical axis chromatic aberration curve of the optical lens 1000 in this embodiment. It can be seen from the figure that the vertical axis chromatic aberration of different wavelengths of the optical lens 1000 is controlled within the range of (-1μm, +5μm), indicating that the vertical axis chromatic aberration of the optical lens 1000 is well controlled and can meet the full-band wide spectrum application requirements.

[0069] Please refer to Figure 3, is the light fan diagram of the optical lens 1000 in this embodiment, in which the horizontal coordinate is the normalized beam aperture and the vertical coordinate is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane d; the vertical coordinate in the image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane d. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. As can be seen from the figure, the optical lens 1000 is close to the horizontal coordinate at each wavelength in each field of view, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously dispersed, indicating that the optical lens 1000 also has a good correction for chromatic aberration, ensuring the imaging requirement of the optical lens 1000 to form a clear image in the full band.

[0070] Please refer to Figure 4 , is a schematic diagram of the field curvature distortion of the optical lens 1000 in this embodiment. Different colors represent different wavelengths. The right curve of the same color is the meridian direction, and the left curve is the sagittal field curvature. From the figure, the sagittal field curvature of this lens is no more than 0.1mm, indicating that this lens can correct chromatic aberration well. Another curve in the figure is the distortion curve of the system. Distortion does not affect the clarity of the system, but it will cause the image of the system to deform. The optical distortion of this lens is less than 4%.

[0071] Please refer to Figure 5 , is a schematic diagram of the MTF of the optical lens 1000 at 20°C in this embodiment, which shows the imaging quality of three wavelengths of light, wherein the horizontal axis represents the number of line pairs, and the vertical axis represents the resolution capability, wherein the higher the value of the vertical axis, the stronger the resolution capability and the higher the image quality restoration degree, wherein the MTF values ​​are all greater than 0.2, which basically meets the imaging quality requirements.

[0072] Please refer to Figure 6 , Figure 8 and Fig. 9 , is a defocus MTF curve diagram of the optical lens 1000 in this embodiment under the visible light band of 20°C, -30°C and 85°C respectively. It can be seen from the figure that the defocus of the lens does not exceed 0.006mm in the three states, basically achieving a state of no defocusing at high and low temperatures.

[0073] Please refer to Figure 7 , is a defocus MTF curve of the optical lens 1000 in this embodiment at 20°C in the infrared band. From the figure, it can be seen that the lens defocus does not exceed 0.018mm, basically reaching a state of no defocus in the infrared band.

[0074] In this embodiment, the focal length of the optical lens 1000 is 2.41 mm, the aperture value is 2.0, the image plane diameter is 6.5 mm, and the diagonal field of view is 160°. While having a large field of view, various aberrations of the lens are corrected, the imaging quality is high, and clear imaging can be achieved even in low light. The lens size is small, and the night vision imaging effect is good. It does not defocus under high and low temperature conditions, especially in the temperature range of -30°C to 85°C, and the working performance is more stable.

[0075] The present invention further proposes an imaging device, which includes the above-mentioned optical lens 1000. Since the imaging device includes the optical lens 1000, the specific structure of the optical lens 1000 refers to the above-mentioned embodiment. Since the optical lens 1000 of the imaging device adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0076] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An optical lens, characterized in that: The optical lens has an object side and an image side which are arranged opposite to each other along the optical axis direction, and the optical lens includes a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with positive optical power and an image plane, which are arranged in sequence from the object side to the image side, so that the horizontal field angle of the optical lens reaches 126° or more, the aperture value is less than or equal to 2.0, and the image plane height reaches 6.6 mm; Among them, the second lens, the third lens, the seventh lens and the eighth lens are plastic aspherical lenses, and the first lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses.

2. The optical lens according to claim 1, wherein: The optical lens further includes a stop, and the stop is disposed between the fourth lens and the fifth lens.

3. The optical lens according to claim 1, wherein: The optical lens further includes a filter and a protective glass which are sequentially arranged between the eighth lens and the image plane from the object side to the image side.

4. The optical lens according to claim 1, wherein: The fifth lens and the sixth lens are cemented and connected.

5. The optical lens according to claim 1, wherein: The first lens is a concave-convex lens, and its object side surface is convex; The second lens is a concave-convex lens, and its object side surface is convex; The third lens is a biconcave lens; The fourth lens is a biconvex lens; The fifth lens is a biconvex lens; The sixth lens is a biconcave lens; The seventh lens is a biconvex lens; The eighth lens is a biconvex lens.

6. The optical lens according to claim 5, characterized in that: The focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is 7, and the focal length of the eighth lens is f8, wherein: -15<f1<-8, -15<f2<-8, -8<f3<-4, 4<f4<9, 3<f5<8, -6<f6<-2, 4<f7<10, 10<f8<25.

7. The optical lens according to claim 5, characterized in that: The refractive index of the first lens is n1, and the dispersion coefficient is v1; the refractive index of the second lens is n2, and the dispersion coefficient is v2; the refractive index of the third lens is n3, and the dispersion coefficient is v3; the focal refractive index of the fourth lens is n4, and the dispersion coefficient is v4; the refractive index of the fifth lens is n5, and the dispersion coefficient is v5; the refractive index of the sixth lens is n6, and the dispersion coefficient is v6; the refractive index of the seventh lens is n7, and the dispersion coefficient is v7; the refractive index of the eighth lens is n8, and the dispersion coefficient is v8, wherein: 1.55≤n1≤1.75, 1 .50≤n2≤1.60, 1.50≤n3≤1.60, 1.75≤n4≤1.95, 1.50≤n5≤1.70, 1.70≤n6≤1.95, 1.50≤n7≤1.60, 1.50≤n8≤1.70, 45.0≤v1≤75.0, 50.0≤v2≤65.0, 50.0≤v3≤65.0, 25.0≤v4≤45.0, 50.0≤v5≤75.0, 25.0≤v6≤35.0, 50.0≤v7≤65.0, 50.0≤v8≤65.

0.

8. The optical lens according to claim 1, wherein: The effective focal length of the optical lens is EFL, and the total optical length of the optical lens is TTL, wherein: TTL / EFL≤10.

5.

9. The optical lens according to claim 1, wherein: The diameter of the first lens is D1, and the image diameter of the optical lens is IC, wherein: D1<15mm, IC≤6.6mm.

10. An imaging device, characterized in that: Comprising the optical lens as described in any one of claims 1 to 9.

Images