A zoom lens

Abstract

The embodiment of the present invention discloses a zoom lens. The zoom lens includes a focusing lens group, an aperture and a zoom lens group arranged from the object side to the image side along the optical axis, and the focusing lens group and the zoom lens group move back and forth along the optical axis during zooming; the focusing lens group includes a first lens with negative focal power, a second lens with negative focal power and a third lens with positive focal power; the zoom lens group includes a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an eighth lens with negative focal power and a ninth lens with positive focal power; the first lens, the seventh lens and the eighth lens are spherical lenses, and the seventh lens and the eighth lens form a cemented lens; the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the ninth lens are aspherical lenses. The scheme of the present invention can have an equivalent focal length of 2.8mm-6mm under the premise of TTL≤33mm, and has the effects of high imaging quality, large aperture and day and night confocality.

Description

Technical Field

[0001] The embodiments of the present invention relate to lens technology, and in particular to a zoom lens. Background Art

[0002] Since the field of view of a fixed-focus lens is fixed, a product can only be used in specific scenarios, resulting in the inability of fixed-focus lenses to meet usage requirements in many scenarios. Since the focal length of a zoom lens is continuously variable, the field of view is also continuously variable within a certain range, and it can adapt to more application scenarios. Therefore, a zoom all-in-one machine including a zoom lens has a wide range of applications in smart transportation, face recognition and other security fields.

[0003] The size of the zoom lens directly affects the volume of the entire camera. For occasions with limited installation space or concealment requirements, small-sized security zoom lenses are widely needed. The current zoom all-in-one cameras are generally over 50mm in length and cannot be made smaller. If you want to reduce the size of the lens, you will face the difficulties of difficult correction of aberrations and difficult enlargement of the imaging target surface. Summary of the invention

[0004] An embodiment of the present invention provides a zoom lens, which can obtain an equivalent focal length range of 2.8mm-6mm under the premise that the total optical length is less than or equal to 33mm, match a 1 / 2.7-inch target surface, and has high imaging quality, a large aperture, and day and night confocal effects.

[0005] An embodiment of the present invention provides a zoom lens, comprising a focusing lens group, an aperture, and a magnification lens group arranged in sequence from the object side to the image side along an optical axis, wherein the focusing lens group and the magnification lens group reciprocate along the optical axis during zooming;

[0006] The focusing lens group comprises a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power, which are arranged in sequence from the object side to the image side;

[0007] The zoom lens group includes a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an eighth lens with negative focal power, and a ninth lens with positive focal power, which are arranged in sequence from the object side to the image side;

[0008] Wherein, the first lens, the seventh lens and the eighth lens are all spherical lenses, and the seventh lens and the eighth lens form a cemented lens;

[0009] The second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the ninth lens are all aspherical lenses.

[0010] Optionally, the zoom lens satisfies:

[0011] -2.2 <F1 / F4<-1.6;

[0012] -1.6 <F2 / F4<-1.2;

[0013] 0.8 <F3 / F4<1.2;

[0014] 0.4 <F5 / F4<0.6;

[0015] -0.8 <F6 / F4<-0.6;

[0016] 0.58 <Fj / F4<0.78;

[0017] 0.6 <F9 / F4<0.9;

[0018] Among them, F1, F2, F3, F4, F5, F6 and F9 represent the optical power of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the ninth lens respectively, and Fj represents the combined optical power of the seventh lens and the eighth lens.

[0019] Optionally, the focal power of the seventh lens and the focal power of the eighth lens satisfy:

[0020] -1.35 <F7 / F8<-1.15;

[0021] The third lens satisfies:

[0022] n3>1.6, v3<30;

[0023] The fourth lens satisfies:

[0024] n4<1.6, v4>75;

[0025] The seventh lens satisfies:

[0026] n7<1.65, v7>60;

[0027] Among them, F7 and F8 represent the optical power of the seventh lens and the eighth lens respectively, n3 and v3 represent the refractive index and the Abbe number of the third lens respectively, n4 and v4 represent the refractive index and the Abbe number of the fourth lens respectively, and n7 and v7 represent the refractive index and the Abbe number of the seventh lens respectively.

[0028] Optionally, the zoom lens satisfies:

[0029] -2.8 <Fa / F4<-2.2;

[0030] 1.7 <Fb / F4<2.1;

[0031] 0.2 <F4 / Fw<0.3;

[0032] 0.3 <F4 / Ft<0.55;

[0033] Among them, Fa represents the optical focal length of the focusing lens group, Fb represents the optical focal length of the zoom lens group, Fw represents the optical focal length of the zoom lens at the wide-angle end, Ft represents the optical focal length of the zoom lens at the telephoto end, and F4 represents the optical focal length of the fourth lens.

[0034] Optionally, the zoom lens satisfies:

[0035] BFLw / TTLw>0.18;

[0036] D1 / TTLw<0.42;

[0037] Among them, BFLw represents the distance from the image side surface of the ninth lens to the image plane at the wide-angle end of the zoom lens, TTLw represents the distance from the object side surface of the first lens to the image plane at the wide-angle end of the zoom lens, and D1 represents the maximum aperture of the first lens.

[0038] Optionally, when the image plane height IH of the zoom lens is 3.3 mm, the field of view angle satisfies:

[0039] 70° <FOVw / 2<80°。

[0040] Optionally, the first lens, the fourth lens, the seventh lens and the eighth lens are all glass lenses, and the second lens, the third lens, the fifth lens, the sixth lens and the ninth lens are all plastic lenses.

[0041] Optionally, the first lens is one of a convex-concave lens, a plano-concave lens or a bi-concave lens, the second lens is a bi-concave lens, and the third lens is one of a convex-concave lens, a convex-plano lens or a bi-convex lens.

[0042] Optionally, the fourth lens is a biconvex lens, the fifth lens is a concave-convex lens, a plano-convex lens or a biconvex lens, the seventh lens is a biconvex lens, the eighth lens is a biconcave lens, a concave-convex lens or a concave-planar lens, and the ninth lens is a convex-concave lens.

[0043] Optionally, the total optical length of the zoom lens is less than or equal to 33 mm.

[0044] The zoom lens provided by the embodiment of the present invention comprises a focusing lens group, an aperture and a variator lens group which are sequentially arranged from the object side to the image side along the optical axis, and the focusing lens group and the variator lens group move back and forth along the optical axis during zooming; the focusing lens group comprises a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power which are sequentially arranged from the object side to the image side; the variator lens group comprises 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 negative optical power and a ninth lens with positive optical power which are sequentially arranged from the object side to the image side; wherein the first lens, the seventh lens and the eighth lens are all spherical lenses, and the seventh lens and the eighth lens constitute a cemented lens; the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the ninth lens are all aspherical lenses. Zooming is achieved by moving the focusing lens group and the zoom lens group back and forth along the optical axis to change the interval between the two lens groups, wherein the focusing lens group plays a focusing role and the zoom lens group plays a zooming role, and the equivalent focal length is 2.8mm-6mm; by reasonably designing the structure of each lens and the optical focal length matching relationship, the zoom lens matches the 1 / 2.7-inch target surface, and has the effects of high imaging quality, large aperture, and day and night confocality. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a structural schematic diagram of a zoom lens provided by an embodiment of the present invention;

[0046] Figure 2 is a schematic structural diagram of a first zoom lens provided by an embodiment of the present invention;

[0047] Figure 3 1 is a schematic diagram of a modulation transfer function MTF curve of a first zoom lens at a wide-angle end at room temperature provided by an embodiment of the present invention;

[0048] Figure 4 is a schematic diagram of a position chromatic aberration curve of a first zoom lens at a wide-angle end provided by an embodiment of the present invention;

[0049] Figure 5 is a schematic diagram of an MTF curve of a first zoom lens at a telephoto end provided by an embodiment of the present invention;

[0050] Figure 6 is a schematic diagram of a position chromatic aberration curve of a first zoom lens at a telephoto end provided by an embodiment of the present invention;

[0051] Figure 7 is a schematic structural diagram of a second zoom lens provided by an embodiment of the present invention;

[0052] Figure 8 is a schematic diagram of the MTF curve of the second zoom lens at the wide-angle end under normal temperature conditions provided by an embodiment of the present invention;

[0053] Fig. 9 is a schematic diagram of a position chromatic aberration curve of a second zoom lens at a wide-angle end provided by an embodiment of the present invention;

[0054] Fig.10 is a schematic diagram of an MTF curve of a second zoom lens at a telephoto end provided by an embodiment of the present invention;

[0055] Fig.11 is a schematic diagram of a position chromatic aberration curve of a second zoom lens at a telephoto end provided by an embodiment of the present invention;

[0056] Fig.12 is a schematic structural diagram of a third zoom lens provided by an embodiment of the present invention;

[0057] Fig.13 is a schematic diagram of the MTF curve of the third zoom lens at the wide-angle end under normal temperature conditions provided by an embodiment of the present invention;

[0058] Fig.14 is a schematic diagram of a position chromatic aberration curve of a third zoom lens at a wide-angle end provided by an embodiment of the present invention;

[0059] Fig.15 is a schematic diagram of an MTF curve of a third zoom lens at a telephoto end provided by an embodiment of the present invention;

[0060] Fig.16 Schematic diagram of position chromatic aberration curve of the third zoom lens at the telephoto end provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0061] 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.

[0062] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. It should be noted that the directional words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present invention are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present invention. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second" and the like are only used for descriptive purposes and do not indicate any order, quantity or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0063] Figure 1 FIG. 1 is a schematic diagram of the structure of a zoom lens provided by an embodiment of the present invention. Figure 1 The zoom lens provided by the embodiment of the present invention comprises a focusing lens group 10, an aperture 30 and a zoom lens group 20 which are sequentially arranged from the object side to the image side along the optical axis. The focusing lens group 10 and the zoom lens group 20 move back and forth along the optical axis during zooming. The focusing lens group 10 comprises a first lens 101 with negative optical power, a second lens 102 with negative optical power and a third lens 103 with positive optical power which are sequentially arranged from the object side to the image side. The zoom lens group 20 comprises a fourth lens 201 with positive optical power, a second lens 102 with positive optical power and a third lens 103 with positive optical power which are sequentially arranged from the object side to the image side. The fifth lens 202, the sixth lens 203 with negative optical power, the seventh lens 204 with positive optical power, the eighth lens 205 with negative optical power and the ninth lens 206 with positive optical power; wherein the first lens 101, the seventh lens 204 and the eighth lens 205 are all spherical lenses, and the seventh lens 204 and the eighth lens 205 form a cemented lens; the second lens 102, the third lens 103, the fourth lens 201, the fifth lens 202, the sixth lens 203 and the ninth lens 206 are all aspherical lenses.

[0064] It can be understood that the focal power is the reciprocal of the focal length, which characterizes the ability of the optical system to bend light. The larger the absolute value of the focal power, the stronger the ability to bend light, and the smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is a positive number, the refraction of light is convergent; when the focal power is a negative number, the refraction of light is divergent. In this embodiment, the focusing lens group 10, the aperture 30 and the variable magnification lens group 20 can be arranged in a lens barrel ( Figure 1(not shown in the figure), the focusing lens group 10 is used to realize the change of the focal length of the lens, and the magnification lens group 20 is used to achieve the magnification change. The zoom function is realized by the combined movement of the focusing lens group 10 and the magnification lens group 20, and various aberrations are eliminated by setting the matching relationship between the spherical and aspherical surfaces of each lens, and chromatic aberration is eliminated by cementing the lens to achieve a clear imaging effect. By setting the optical power relationship of each lens, an equivalent focal length segment of 2.8mm-6mm can be obtained on the premise that the total optical length is less than or equal to 33mm, matching the 1 / 2.7-inch target surface, and having the effects of high imaging quality, large aperture and day and night confocality.

[0065] In this embodiment, the surface shape of the aspheric lens satisfies the formula:

[0066]

[0067] Where z represents the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of y along the optical axis. It represents the radius of curvature of the surface center, k represents the cone coefficient, and a1, a2, a3, a4, a5, a6, a7, and a8 represent high-order aspheric coefficients.

[0068] The technical solution of this embodiment realizes zooming by causing the focusing lens group and the zoom lens group to move back and forth along the optical axis during zooming to change the interval between the two lens groups, wherein the focusing lens group plays a focusing role and the zoom lens group plays a zooming role, and the equivalent focal length thereof is 2.8mm-6mm; by reasonably designing the structure of each lens and the optical focal length matching relationship, the zoom lens is matched with a 1 / 2.7-inch target surface, and has the effects of high imaging quality, large aperture, and day and night confocality.

[0069] On the basis of the above technical solution, optionally, the zoom lens meets the following requirements:

[0070] -2.2 <F1 / F4<-1.6;

[0071] -1.6 <F2 / F4<-1.2;

[0072] 0.8 <F3 / F4<1.2;

[0073] 0.4 <F5 / F4<0.6;

[0074] -0.8 <F6 / F4<-0.6;

[0075] 0.58 <Fj / F4<0.78;

[0076] 0.6 <F9 / F4<0.9;

[0077] Among them, F1, F2, F3, F4, F5, F6 and F9 respectively represent the optical power of the first lens 101, the second lens 102, the third lens 103, the fourth lens 201, the fifth lens 202, the sixth lens 203 and the ninth lens 206, and Fj represents the combined optical power of the seventh lens 204 and the eighth lens 205.

[0078] Among them, the focal power is the reciprocal of the focal length. In this embodiment, the focal length, focal power, refractive index, Abbe number and other parameters of the lens are all determined for a wavelength of 587.56nm. The fourth lens 201 is the main component of the lens for focusing and imaging, and is designed as a convergent lens with positive focal power. The other lenses are used to correct aberrations such as spherical aberration, coma, field curvature, and astigmatism during the light transmission process. The first lens 101 and the second lens 102 are both negative focal power lenses, and the aperture of the first lens 101 is large, so as to facilitate receiving external light and ensure the field of view of the lens; the third lens 103 is a positive focal power lens, which is used to correct the spherical aberration of the first two lenses; the first lens 101 to the third lens 103 are combined to form a focusing lens group, which is used to achieve the change of the focal length of the lens; the seventh lens 204 and the eighth lens 205 constitute a cemented lens, which is used to correct chromatic aberration; the focal power of each lens is set to meet the ratio requirements of each focal power, so as to achieve a clear visible light imaging effect.

[0079] Optionally, the focal power of the seventh lens 204 and the focal power of the eighth lens 205 satisfy:

[0080] -1.35 <F7 / F8<-1.15;

[0081] The third lens 103 satisfies:

[0082] n3>1.6, v3<30;

[0083] The fourth lens 201 satisfies:

[0084] n4<1.6, v4>75;

[0085] The seventh lens 204 satisfies:

[0086] n7<1.65, v7>60;

[0087] Among them, F7 and F8 represent the optical powers of the seventh lens 204 and the eighth lens 205 respectively, n3 and v3 represent the refractive index and the Abbe number of the third lens 103 respectively, n4 and v4 represent the refractive index and the Abbe number of the fourth lens 201 respectively, and n7 and v7 represent the refractive index and the Abbe number of the seventh lens 204 respectively.

[0088] It is understandable that the seventh lens 204 and the eighth lens 205 are double-glued lenses with positive and negative optical powers. By setting -1.35 < F7 / F8 < -1.15, the magnification chromatic aberration can be effectively corrected. By setting the refractive indices and Abbe numbers of the third lens 103, the fourth lens 201, and the seventh lens 204 to satisfy n3 > 1.6, v3 < 30, n4 < 1.6, v4 > 75, n7 < 1.65, and v7 > 60, the day-night confocal ability of the lens can be effectively improved, and the night infrared imaging effect can be guaranteed.

[0089] Optionally, in order to ensure that the zoom lens achieves an appropriate zoom ratio, the zoom lens satisfies:

[0090] -2.8 < Fa / F4 < -2.2;

[0091] 1.7 < Fb / F4 < 2.1;

[0092] 0.2 < F4 / Fw < 0.3;

[0093] 0.3 < F4 / Ft < 0.55;

[0094] Wherein, Fa represents the optical power of the focusing lens group 10, Fb represents the optical power of the variable magnification lens group 20, Fw represents the optical power of the zoom lens at the wide-angle end, Ft represents the optical power of the zoom lens at the telephoto end, and F4 represents the optical power of the fourth lens 201.

[0095] Optionally, in order to avoid interference between the zoom lens and the base and the housing during installation, the zoom lens satisfies:

[0096] BFLw / TTLw > 0.18;

[0097] D1 / TTLw < 0.42;

[0098] Wherein, BFLw represents the distance from the image-side surface of the ninth lens 206 to the image plane at the wide-angle end of the zoom lens, TTLw represents the distance from the object-side surface of the first lens 101 to the image plane at the wide-angle end of the zoom lens, and D1 represents the maximum clear aperture of the first lens 101.

[0099] Optionally, when the image plane height IH of the zoom lens is 3.3 mm, the field of view angle satisfies:

[0100] 70° < FOVw / 2 < 80°.

[0101] Optionally, the first lens 101, the fourth lens 201, the seventh lens 204, and the eighth lens 205 are all glass lenses, and the second lens 102, the third lens 103, the fifth lens 202, the sixth lens 203, and the ninth lens 206 are all plastic lenses.

[0102] Among them, the first lens 101, the seventh lens 204 and the eighth lens 205 are all glass spherical lenses, which are easy to process and help reduce the cost of the zoom lens; the fourth lens 201 is a core component and adopts an aspherical lens, which helps to correct aberrations; the second lens 102, the third lens 103, the fifth lens 202, the sixth lens 203 and the ninth lens 206 are all plastic aspherical lenses, which can ensure low costs while improving imaging quality as much as possible.

[0103] Optionally, the first lens 101 is one of a convex-concave lens, a plano-concave lens or a bi-concave lens, the second lens 102 is a bi-concave lens, and the third lens 103 is one of a convex-concave lens, a convex-plano lens or a bi-convex lens.

[0104] Optionally, the fourth lens 201 is a biconvex lens, the fifth lens 202 is a concave-convex lens, a plano-convex lens or a biconvex lens, the seventh lens 204 is a biconvex lens, the eighth lens 205 is a biconcave lens, a concave-convex lens or a concave-planar lens, and the ninth lens 206 is a convex-concave lens.

[0105] It is understandable that the above lens shapes are only schematic, and the shapes of the lenses can be designed according to actual conditions during implementation. Optionally, during implementation, the lenses can be directly supported by Mylar sheets or spacers.

[0106] For example, Figure 2 FIG. 1 is a schematic diagram of the structure of a first zoom lens provided by an embodiment of the present invention. Table 1 shows the parameter design values ​​of the first zoom lens:

[0107] Table 1 Design value of a parameter of the first zoom lens

[0108] Example 1 Lower limit Upper limit F1 / F4 -2.05 -2.20 -1.60 F2 / F4 -1.50 -1.60 -1.20 F3 / F4 1.05 0.80 1.20 F5 / F4 0.55 0.40 0.60 F6 / F4 -0.71 -0.80 -0.60 F7 / F8 -1.25 -1.35 -1.15 F9 / F4 0.80 0.60 0.90 Fj / F4 0.75 0.58 0.78 Fa / F4 -2.63 -2.80 -2.20 Fb / F4 1.83 1.70 2.10 F4 / Fw 0.24 0.20 0.30 F4 / Ft 0.41 0.30 0.55 n3 1.6613 1.6 v3 20.4 30 n4 1.4586 1.6 v4 90.2 75 n7 1.5928 1.65 v7 68.4 60 BFLw / TTLw 0.203 0.18 D1 / TTL 0.370 0.42

[0109] Table 2 shows the specific design values ​​of the parameters of each lens of the first zoom lens:

[0110] Table 2 Design values ​​of lens parameters of the first zoom lens

[0111]

[0112]

[0113] Wherein, surface number 1 represents the front surface of the first lens 101 (the surface close to the object side), surface number 2 represents the rear surface of the first lens 101 (the surface close to the image side), and so on, where surface number 15 is the bonding surface of the seventh lens 204 and the eighth lens 205; surface numbers 19 and 20 represent the front surface and the rear surface of the lens protection glass respectively. The radius of curvature represents the curvature of the lens surface, a positive value represents the surface bending toward the image side, and a negative value represents the surface bending toward the object side, where "INF" represents 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 represents the ability of the material between the current surface and the next surface to deflect light, and the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light.

[0114] Table 3 shows the zoom interval values ​​in Table 2:

[0115] Table 3 A design value of zoom interval

[0116] Wide-angle end Telephoto end Zoom interval 1 5.984 0.796 Zoom interval 2 4.092 7.552

[0117] Table 4 shows the aspheric surface parameters of the first zoom lens:

[0118] Table 4 A design value of the aspheric coefficient in the first fixed-focus lens

[0119]

[0120]

[0121] Among them, -3.476339E-06 means that the a1 coefficient of face number 3 is -3.476339×10 -6 .

[0122] Figure 3 FIG. 1 is a schematic diagram of a modulation transfer function (MTF) curve of a first zoom lens at a wide angle end at room temperature provided by an embodiment of the present invention. Figure 3 From the MTF curve in the middle, we can see that the image quality of this zoom lens has reached a relatively high level. Figure 4 FIG. 1 is a schematic diagram of a position chromatic aberration curve of a first zoom lens at a wide-angle end provided by an embodiment of the present invention. Figure 4 It can be seen that the positional chromatic aberration of the 850nm wavelength has been well corrected, and the day and night confocal function of the lens has reached a good level. Figure 5 FIG. 1 is a schematic diagram of an MTF curve of a first zoom lens at a telephoto end provided by an embodiment of the present invention, wherein Figure 5 From the MTF curve in the middle, we can see that the image quality of this zoom lens has reached a relatively high level. Figure 6 FIG. 1 is a schematic diagram of a position chromatic aberration curve of a first zoom lens at a telephoto end provided by an embodiment of the present invention. Figure 6 It can be seen that the positional chromatic aberration of the 850nm wavelength has been well corrected, and the day and night confocal function of the lens has reached a good level.

[0123] For example, Figure 7 FIG. 5 is a schematic diagram of the structure of a second zoom lens provided by an embodiment of the present invention. Table 5 shows the parameter design values ​​of the second zoom lens:

[0124] Table 5 Design value of a parameter of the second zoom lens

[0125] Example 2 Lower limit Upper limit F1 / F4 -1.78 -2.20 -1.60 F2 / F4 -1.35 -1.60 -1.20 F3 / F4 0.92 0.80 1.20 F5 / F4 0.45 0.40 0.60 F6 / F4 -0.65 -0.80 -0.60 F7 / F8 -1.23 -1.35 -1.15 F9 / F4 0.71 0.60 0.90 Fj / F4 0.63 0.58 0.78 Fa / F4 -2.36 -2.80 -2.20 Fb / F4 1.83 1.70 2.10 F4 / Fw 0.27 0.20 0.30 F4 / Ft 0.46 0.30 0.55 n3 1.6614 1.6 v3 20.4 30 n4 1.4970 1.6 v4 81.6 75 n7 1.5928 1.65 v7 68.3 60 BFLw / TTLw 0.254 0.18 D1 / TTL 0.378 0.42

[0126] Table 6 shows the specific design values ​​of the parameters of each lens of the second zoom lens:

[0127] Table 6 Design values ​​of lens parameters of the second zoom lens

[0128]

[0129] Wherein, surface number 1 represents the front surface of the first lens 101 (the surface close to the object side), surface number 2 represents the rear surface of the first lens 101 (the surface close to the image side), and so on, where surface number 15 is the bonding surface of the seventh lens 204 and the eighth lens 205; surface numbers 19 and 20 represent the front surface and the rear surface of the lens protection glass respectively. The radius of curvature represents the curvature of the lens surface, a positive value represents the surface bending toward the image side, and a negative value represents the surface bending toward the object side, where "INF" represents 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 represents the ability of the material between the current surface and the next surface to deflect light, and the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light.

[0130] Table 7 shows the zoom interval values ​​in Table 6:

[0131] Table 6 A design value of zoom interval

[0132] Wide angle Telephoto end Zoom interval 1 5.810 0.874 Zoom interval 2 4.025 7.433

[0133] Table 8 shows the aspheric surface parameters of the second zoom lens:

[0134] Table 8 A design value of the aspheric coefficient in the second fixed-focus lens

[0135]

[0136]

[0137] Among them, -5.129259E-06 means that the a1 coefficient of surface number 3 is -5.129259×10 -6 .

[0138] Figure 8 FIG. 1 is a schematic diagram of the MTF curve of the second zoom lens provided by an embodiment of the present invention at the wide-angle end under normal temperature conditions. Figure 8 From the MTF curve in the middle, we can see that the image quality of this zoom lens has reached a relatively high level. Fig. 9 FIG. 1 is a schematic diagram of a position chromatic aberration curve of a second zoom lens at a wide angle end provided by an embodiment of the present invention. Fig. 9 It can be seen that the positional chromatic aberration of the 850nm wavelength has been well corrected, and the day and night confocal function of the lens has reached a good level. Fig.10 FIG. 1 is a schematic diagram of an MTF curve of a second zoom lens at a telephoto end provided by an embodiment of the present invention. Fig.10 From the MTF curve in the middle, we can see that the image quality of this zoom lens has reached a relatively high level. Fig.11 FIG. 1 is a schematic diagram of a position chromatic aberration curve of a second zoom lens at a telephoto end provided by an embodiment of the present invention. Fig.11 It can be seen that the positional chromatic aberration of the 850nm wavelength has been well corrected, and the day and night confocal function of the lens has reached a good level.

[0139] For example, Fig.12 FIG. 9 is a schematic diagram of the structure of a third zoom lens provided by an embodiment of the present invention. Table 9 shows the parameter design values ​​of the third zoom lens:

[0140] Table 9 Design value of a parameter of the third zoom lens

[0141]

[0142]

[0143] Table 10 shows the specific design values ​​of the parameters of each lens of the third zoom lens:

[0144] Table 10 Design values ​​of lens parameters of the third zoom lens

[0145]

[0146]

[0147] Wherein, surface number 1 represents the front surface of the first lens 101 (the surface close to the object side), surface number 2 represents the rear surface of the first lens 101 (the surface close to the image side), and so on, where surface number 15 is the bonding surface of the seventh lens 204 and the eighth lens 205; surface numbers 19 and 20 represent the front surface and the rear surface of the lens protection glass respectively. The radius of curvature represents the curvature of the lens surface, a positive value represents the surface bending toward the image side, and a negative value represents the surface bending toward the object side, where "INF" represents 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 represents the ability of the material between the current surface and the next surface to deflect light, and the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light.

[0148] Table 11 shows the zoom interval values ​​in Table 10:

[0149] Table 11 A design value of zoom interval

[0150] Wide angle Telephoto end Zoom interval 1 5.881 0.827 Zoom interval 2 4.047 7.463

[0151] Table 12 shows the aspheric surface parameters of the third zoom lens:

[0152] Table 12 A design value of the aspheric coefficient in the third fixed-focus lens

[0153]

[0154]

[0155] Among them, 2.569664E-05 means that the a1 coefficient of surface number 3 is 2.569664E-05×10 -5 .

[0156] Fig.13 FIG. 1 is a schematic diagram of the MTF curve of the third zoom lens at the wide-angle end under normal temperature conditions provided by an embodiment of the present invention. Fig.13 From the MTF curve in the middle, we can see that the image quality of this zoom lens has reached a relatively high level. Fig.14 FIG. 1 is a schematic diagram of a position chromatic aberration curve of a third zoom lens at a wide-angle end provided by an embodiment of the present invention. Fig.14 It can be seen that the positional chromatic aberration of the 850nm wavelength has been well corrected, and the day and night confocal function of the lens has reached a good level. Fig.15 FIG. 1 is a schematic diagram of an MTF curve of a third zoom lens at the telephoto end provided by an embodiment of the present invention. Fig.15 From the MTF curve in the middle, we can see that the image quality of this zoom lens has reached a relatively high level. Fig.16 FIG. 1 is a schematic diagram of a position chromatic aberration curve of a third zoom lens at the telephoto end provided by an embodiment of the present invention. Fig.16 It can be seen that the positional chromatic aberration of the 850nm wavelength has been well corrected, and the day and night confocal function of the lens has reached a good level.

[0157] 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 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. A zoom lens, characterized in that: It comprises a focusing lens group, an aperture and a magnification lens group which are sequentially arranged along the optical axis from the object side to the image side, and the focusing lens group and the magnification lens group reciprocate along the optical axis during zooming; The focusing lens group comprises a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power, which are arranged in sequence from the object side to the image side; The zoom lens group includes a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an eighth lens with negative focal power, and a ninth lens with positive focal power, which are arranged in sequence from the object side to the image side; Wherein, the first lens, the seventh lens and the eighth lens are all spherical lenses, and the seventh lens and the eighth lens form a cemented lens; The second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the ninth lens are all aspherical lenses; The zoom lens meets the following requirements: BFLw / TTLw>0.18; D1 / TTLw<0.42; Wherein, BFLw represents the distance from the image side surface of the ninth lens to the image plane at the wide-angle end of the zoom lens, TTLw represents the distance from the object side surface of the first lens to the image plane at the wide-angle end of the zoom lens, and D1 represents the maximum aperture of the first lens; The total optical length of the zoom lens is less than or equal to 33 mm.

2. The zoom lens according to claim 1, wherein: The zoom lens meets the following requirements: -2.2 <F1 / F4<-1.6; -1.6 <F2 / F4<-1.2; 0.8 <F3 / F4<1.2; 0.4 <F5 / F4<0.6; -0.8 <F6 / F4<-0.6; 0.58 <Fj / F4<0.78; 0.6 <F9 / F4<0.9; Among them, F1, F2, F3, F4, F5, F6 and F9 represent the optical power of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the ninth lens respectively, and Fj represents the combined optical power of the seventh lens and the eighth lens.

3. The zoom lens according to claim 1, wherein: The focal power of the seventh lens and the focal power of the eighth lens satisfy: -1.35 <F7 / F8<-1.15; The third lens satisfies: n3>1.6, v3<30; The fourth lens satisfies: n4<1.6, v4>75; The seventh lens satisfies: n7<1.65, v7>60; Among them, F7 and F8 represent the optical power of the seventh lens and the eighth lens respectively, n3 and v3 represent the refractive index and the Abbe number of the third lens respectively, n4 and v4 represent the refractive index and the Abbe number of the fourth lens respectively, and n7 and v7 represent the refractive index and the Abbe number of the seventh lens respectively.

4. The zoom lens according to claim 1, wherein: The zoom lens meets the following requirements: -2.8 <Fa / F4<-2.2; 1.7 <Fb / F4<2.1; 0.2 <F4 / Fw<0.3; 0.3 <F4 / Ft<0.55; Among them, Fa represents the optical focal length of the focusing lens group, Fb represents the optical focal length of the zoom lens group, Fw represents the optical focal length of the zoom lens at the wide-angle end, Ft represents the optical focal length of the zoom lens at the telephoto end, and F4 represents the optical focal length of the fourth lens.

5. The zoom lens according to claim 1, wherein: When the image plane height IH of the zoom lens is 3.3 mm, the field angle satisfies: 70° <FOVw / 2<80°。 6. The zoom lens according to claim 1, wherein: The first lens, the fourth lens, the seventh lens and the eighth lens are all glass lenses, and the second lens, the third lens, the fifth lens, the sixth lens and the ninth lens are all plastic lenses.

7. The zoom lens according to claim 1, wherein: The first lens is one of a convex-concave lens, a plano-concave lens or a bi-concave lens, the second lens is a bi-concave lens, and the third lens is one of a convex-concave lens, a convex-plano lens or a bi-convex lens.

8. The zoom lens according to claim 1, wherein: The fourth lens is a biconvex lens, the fifth lens is a concave-convex lens, a plano-convex lens or a biconvex lens, the seventh lens is a biconvex lens, the eighth lens is a biconcave lens, a concave-convex lens or a concave-planar lens, and the ninth lens is a convex-concave lens.

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