Zoom lens and imaging device

Abstract

The application relates to the field of optics, in particular to a zoom lens and an imaging device. The zoom lens is composed of a first lens group with negative focal length, an aperture, a second lens group with positive focal length and a third lens group with negative focal length from the object plane side to the image plane side; the second lens group moves along the direction of the main optical axis; the third lens group is an eighth lens with negative focal length; the two side curved surfaces of the eighth lens are curved towards the object plane side; the eighth lens satisfies the following conditional expressions: D8 / fw>1; 1.8<ft / fw<2.2; wherein D8 is the thickness of the eighth lens on the main optical axis, fw is the focal length of the zoom lens in the wide-angle state, and ft is the focal length of the zoom lens in the telephoto state. The small-ratio zoom lens is realized, the thickness of the rear group is increased through the limitation of the thickness of the eighth lens on the main optical axis, the volume of the rear group is reduced, and the miniaturization of the zoom lens is realized.

Description

Technical Field

[0001] This invention relates to the field of optics, specifically to a zoom lens and an imaging device. Background Technology

[0002] A zoom lens is a lens that can change its focal length within a certain range to obtain different widths of field of view, different sizes of images, and different ranges of objects. A zoom lens can change the shooting range by changing the focal length without changing the shooting distance, which is very beneficial for image composition.

[0003] With the increasing popularity of zoom lenses, they are playing an important role in more and more fields such as surveillance and video conferencing. However, current zoom lenses mainly use glass lenses, which are increasingly unable to meet the growing demand for low cost, low weight, and high image quality in surveillance lenses.

[0004] Currently, small zoom lenses typically have a larger front aperture and a smaller rear aperture, making them unsuitable for applications with smaller apertures. Summary of the Invention

[0005] This invention will solve the existing technical problems and provide a zoom lens and imaging device, realizing a small-magnification zoom lens. At the same time, by limiting the thickness of the eighth lens on the principal optical axis, the thickness of the rear group is increased and the volume of the rear group is reduced, thus realizing the miniaturization of the zoom lens.

[0006] The technical solution provided by this invention is as follows:

[0007] A zoom lens, wherein the zoom lens is composed of a first lens group with negative optical power, an aperture, a second lens group with positive optical power, and a third lens group with negative optical power, in sequence from the object plane side to the image plane side.

[0008] The second lens group moves along the direction of the principal optical axis;

[0009] The third lens group is an eighth lens with negative optical power;

[0010] Both curved surfaces of the eighth lens are bent toward the object surface;

[0011] The eighth lens satisfies the following condition:

[0012] D8 / fw > 1;

[0013] 1.8 < ft / fw < 2.2;

[0014] Wherein, D8 is the thickness of the eighth lens on the principal optical axis, fw is the focal length of the zoom lens in wide-angle mode, and ft is the focal length of the zoom lens in telephoto mode.

[0015] In this technical solution, a small-magnification zoom lens is achieved by limiting the above parameters. At the same time, by limiting the thickness of the eighth lens on the principal optical axis, the thickness of the rear group is increased and the volume of the rear group is reduced, thus achieving miniaturization of the zoom lens.

[0016] Preferably, the first lens group consists of a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0017] Preferably, the second lens group consists of a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, and a seventh lens with positive optical power, sequentially from the object plane side to the image plane side.

[0018] or

[0019] The second lens group consists of a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0020] Preferably, the zoom lens includes at least three aspherical lenses.

[0021] In this technical solution, by setting multiple aspherical surfaces, the coma and aberration of the zoom lens are reduced, the imaging quality of the zoom lens is increased, and the number of lenses in the zoom lens is reduced, thus realizing the miniaturization of the zoom lens.

[0022] Preferably, the aperture stop is disposed on the object plane side of the fourth lens.

[0023] In this technical solution, by setting the aperture stop on the moving group, the volume occupied by the aperture stop is reduced, thus achieving miniaturization of the zoom lens. At the same time, it can also reduce the degree of aperture number change of the moving group during zooming, thus achieving the effect of constant aperture of the zoom lens.

[0024] Preferably, the image plane side of the fourth lens is bent toward the object plane side.

[0025] Preferably, the eighth lens moves along the direction of the principal optical axis;

[0026] The zoom lens satisfies the following condition:

[0027] D8Imin / fw > 1.2;

[0028] Wherein, D8Imin is the minimum distance between the eighth lens and the image plane.

[0029] In this technical solution, by limiting the above parameters, it is easy to adjust the distance between the eighth lens and the image plane, so that the light path can be stably converged on the image plane, thereby increasing the reliability of imaging.

[0030] Preferably, the third lens group includes at least two protective glass panes between itself and the image plane.

[0031] In this technical solution, the imaging position of the optical path is further adjusted by setting multiple protective glasses, which further enables the optical path to converge stably on the image surface and increases the reliability of imaging.

[0032] Preferably, the zoom lens satisfies the following condition:

[0033] D12min / fw < 0.2;

[0034] Wherein, D12min is the minimum distance between the first lens group and the second lens group.

[0035] In this technical solution, by limiting the above parameters, the size of the zoom lens is reduced, and the zoom lens is miniaturized.

[0036] Preferably, the zoom lens satisfies the following condition:

[0037] ΣXG2 / fw<0.1;

[0038] Wherein, ΣXG2 is the sum of the distances between the second lens groups.

[0039] In this technical solution, by limiting the sum of the spacing between the second lens groups, the utilization rate of each lens in the second lens group is increased, thereby reducing the number of lenses in the second lens group and realizing the miniaturization of the zoom lens.

[0040] Preferably, the zoom lens satisfies the following condition:

[0041] 1.5 < S² / fw < 1.8;

[0042] Wherein, S2 is the moving distance of the second lens group.

[0043] In this technical solution, by limiting the above parameters, the zoom range of the zoom lens is increased, thereby increasing the applicability of the zoom lens.

[0044] One of the objectives of this invention is to provide an imaging device, comprising: a zoom lens; and an imaging element configured to receive an image formed by the zoom lens.

[0045] Compared with the prior art, the zoom lens and imaging device provided by the present invention have the following beneficial effects:

[0046] 1. This invention realizes a small-magnification zoom lens. At the same time, by limiting the thickness of the eighth lens on the principal optical axis, the thickness of the rear group is increased and the volume of the rear group is reduced, thereby realizing the miniaturization of the zoom lens.

[0047] 2. By using multiple aspherical surfaces, coma and aberrations in the zoom lens are reduced, the image quality of the zoom lens is increased, and the number of lenses in the zoom lens is reduced, thus achieving miniaturization of the zoom lens.

[0048] 3. By placing the aperture stop on the moving group, the volume occupied by the aperture stop is reduced, thus achieving miniaturization of the zoom lens. At the same time, it also reduces the degree of aperture number change of the moving group during zooming, achieving a constant aperture effect for the zoom lens. Attached Figure Description

[0049] The preferred embodiments will now be described in a clear and easy-to-understand manner, with reference to the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of a zoom lens and imaging device.

[0050] Figure 1 This is a schematic diagram of the structure of a zoom lens according to the present invention;

[0051] Figure 2 This is an aberration diagram of a zoom lens in telephoto mode according to the present invention;

[0052] Figure 3 This is a first coma diagram of a zoom lens in telephoto mode according to the present invention;

[0053] Figure 4 This is a second coma diagram of a zoom lens in telephoto mode according to the present invention;

[0054] Figure 5 This is an aberration diagram of a zoom lens in a wide-angle state according to the present invention;

[0055] Figure 6 This invention provides a first coma diagram of a zoom lens in a wide-angle state.

[0056] Figure 7 This invention provides a second coma diagram of a zoom lens in a wide-angle state.

[0057] Figure 8 This is a schematic diagram of another zoom lens according to the present invention;

[0058] Figure 9 This is another aberration diagram of the zoom lens in telephoto mode according to the present invention;

[0059] Figure 10 This is a first coma diagram of another zoom lens telephoto state according to the present invention;

[0060] Figure 11 This is a second coma diagram of another zoom lens telephoto state according to the present invention;

[0061] Figure 12This is another aberration diagram of the zoom lens in the wide-angle state according to the present invention;

[0062] Figure 13 This is a first coma diagram of another zoom lens in a wide-angle state according to the present invention;

[0063] Figure 14 This is a second coma diagram of another zoom lens in a wide-angle state according to the present invention;

[0064] Figure 15 This is a schematic diagram of the structure of another zoom lens of the present invention;

[0065] Figure 16 This is another aberration diagram of the zoom lens in telephoto mode according to the present invention;

[0066] Figure 17 This is a first coma diagram of another zoom lens in telephoto mode according to the present invention;

[0067] Figure 18 This is a second coma diagram of a zoom lens in a telephoto state according to the present invention;

[0068] Figure 19 This is another aberration diagram of a zoom lens in a wide-angle state according to the present invention;

[0069] Figure 20 This is a first coma diagram of a zoom lens in a wide-angle state according to another invention;

[0070] Figure 21 This is a second coma diagram of a zoom lens in a wide-angle state according to the present invention.

[0071] The reference numerals are as follows: G1, first lens group; G2, second lens group; G3, third lens group; G4, auxiliary component; L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; L8, eighth lens; STO, aperture stop; CG1, first protective glass; CG2, second protective glass. Detailed Implementation

[0072] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0073] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one." Example

[0074] like Figure 1 , 8 As shown in Figure 15, a zoom lens, the zoom lens comprising, from the object plane side to the image plane side, the following components:

[0075] The first lens group with negative optical power is G1, the aperture is STO, the second lens group with positive optical power is G2, and the third lens group with negative optical power is G3.

[0076] The second lens group G2 moves along the direction of the principal optical axis;

[0077] The third lens group G3 is an eighth lens L8 with negative optical power;

[0078] Both curved surfaces of the eighth lens L8 are bent toward the object surface;

[0079] The eighth lens L8 satisfies the following condition:

[0080] D8 / fw > 1;

[0081] 1.8 < ft / fw < 2.2;

[0082] Wherein, D8 is the thickness of the eighth lens L8 on the principal optical axis, fw is the focal length of the zoom lens in wide-angle mode, and ft is the focal length of the zoom lens in telephoto mode.

[0083] In this embodiment, by limiting the above parameters, a small-magnification zoom lens is realized. At the same time, by limiting the thickness of the eighth lens L8 on the main optical axis, the thickness of the rear group is increased and the volume of the rear group is reduced, thus realizing the miniaturization of the zoom lens.

[0084] The first lens group G1, from the object plane side to the image plane side, includes the following:

[0085] A first lens L1 with negative optical power, a second lens L2 with negative optical power, and a third lens L3 with positive optical power.

[0086] The second lens group G2 includes, from the object plane side to the image plane side, the following:

[0087] The fourth lens L4 has positive optical power, the fifth lens L5 has positive optical power, the sixth lens L6 has negative optical power, and the seventh lens L7 has positive optical power.

[0088] or

[0089] The second lens group G2 includes, from the object plane side to the image plane side, the following:

[0090] The fourth lens L4 has positive optical power, the fifth lens L5 has negative optical power, the sixth lens L6 has positive optical power, and the seventh lens L7 has positive optical power.

[0091] The zoom lens includes at least three aspherical lenses.

[0092] In this embodiment, by setting multiple aspherical surfaces, the coma and aberration of the zoom lens are reduced, the imaging quality of the zoom lens is increased, and the number of lenses in the zoom lens is reduced, thus achieving miniaturization of the zoom lens.

[0093] The aperture stop STO is located on the object plane side of the fourth lens L4.

[0094] By placing the aperture stop STO on the moving group, the volume occupied by the aperture stop STO is reduced, thus achieving miniaturization of the zoom lens. At the same time, the degree of aperture number change of the moving group during zooming is also reduced, achieving a constant aperture effect for the zoom lens.

[0095] The image plane side of the fourth lens L4 is bent toward the object plane side.

[0096] The eighth lens L8 moves along the direction of the principal optical axis;

[0097] The zoom lens satisfies the following condition:

[0098] D8Imin / fw > 1.2;

[0099] Wherein, D8Imin is the minimum distance between the eighth lens L8 and the image plane.

[0100] In this embodiment, by limiting the above parameters, it is easy to adjust the distance between the eighth lens L8 and the image plane, so that the light path can be stably converged on the image plane, thereby increasing the reliability of imaging.

[0101] The third lens group G3 includes at least two protective glasses between itself and the image plane.

[0102] In this embodiment, by setting multiple protective glasses, the imaging position of the optical path is further adjusted, which further enables the optical path to converge stably on the image surface and increases the reliability of imaging.

[0103] The zoom lens satisfies the following condition:

[0104] D12min / fw < 0.2;

[0105] Wherein, D12min is the minimum distance between the first lens group G1 and the second lens group G2.

[0106] In this embodiment, by limiting the above parameters, the size of the zoom lens is reduced, and the zoom lens is miniaturized.

[0107] The zoom lens satisfies the following condition:

[0108] ΣXG2 / fw<0.1;

[0109] Wherein, ΣXG2 is the sum of the distances between the second lens group G2.

[0110] By limiting the sum of the spacing between the second lens group G2, the utilization rate of each lens in the second lens group G2 is increased, thereby reducing the number of lenses in the second lens group G2 and realizing the miniaturization of the zoom lens.

[0111] The zoom lens satisfies the following condition:

[0112] 1.5 < S² / fw < 1.8;

[0113] Wherein, S2 is the moving distance of the second lens group G2.

[0114] By limiting the parameters mentioned above, the zoom range of the zoom lens is increased, thereby increasing the applicability of the zoom lens. Example

[0115] like Figures 1 to 7 As shown, a zoom lens, comprising, from the object plane side to the image plane side, the following components:

[0116] The first lens group G1 with negative optical power, the aperture stop STO, the second lens group G2 with positive optical power, the third lens group G3 with negative optical power, and the auxiliary component G4.

[0117] The first lens group G1, from the object plane side to the image plane side, includes the following:

[0118] A first lens L1 with negative optical power, a second lens L2 with negative optical power, and a third lens L3 with positive optical power.

[0119] The second lens group G2 includes, from the object plane side to the image plane side, the following:

[0120] The fourth lens L4 has positive optical power, the fifth lens L5 has positive optical power, the sixth lens L6 has negative optical power, and the seventh lens L7 has positive optical power.

[0121] The third lens group G3 is an eighth lens L8 with negative optical power;

[0122] The auxiliary component G4 includes, from the object plane side to the image plane side, the following components in sequence: a first protective glass CG1 and a second protective glass CG2.

[0123] The basic lens data of the zoom lens in this embodiment is shown in Table 1, the variable parameters in Table 1 are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0124] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0125] In Table 2, the WIDE column indicates the specific values ​​of each variable parameter when the zoom lens is in the wide-angle position, and the TELE column indicates the specific values ​​of each variable parameter when the zoom lens is in the telephoto position.

[0126] In Table 3, K is the conic coefficient, and e is the scientific notation, for example, e-005 represents 10. -5 .

[0127] Table 1

[0128] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 spherical 58.04 0.50 1.497 81.61 S2 spherical 3.96 2.49 S3 aspherical 83.69 0.54 1.531 55.77 S4 aspherical 4.53 0.23 S5 aspherical 9.74 1.91 1.661 20.38 S6 aspherical 66.88 D1 STO aspherical 4.99 2.91 1.535 56.09 S8 aspherical 8.47 0.21 S9 spherical 8.79 3.02 1.437 95.10 S10 spherical -3.47 1.32 1.805 25.46 S11 spherical -5.80 0.10 S12 spherical 24.15 2.05 1.437 95.10 S13 spherical -15.77 D2 S14 aspherical 14.03 3.62 1.635 23.98 S15 aspherical 10.67 1.90 S16 spherical INF 0.30 1.517 64.20 S17 spherical INF 1.50 S18 spherical INF 0.50 1.517 64.20 S19 spherical INF 0.40 IMG

[0129] Table 2

[0130] WIDE TELE D1 6.08 0.46 D2 0.4 6.02

[0131] Table 3

[0132] Quadratic surface constant (K) 4th order coefficients (A) 6th order coefficients (B) 8th order coefficients (C) 10th-order coefficients (D) S3 0 -1.0E-02 1.5E-03 -3.1E-04 2.8E-05 S4 0 -1.2E-02 2.7E-03 -5.8E-04 3.1E-05 S5 0 3.0E-04 -7.0E-05 -3.6E-06 1.2E-07 S6 0 -3.9E-04 -5.0E-05 1.3E-05 -4.7E-07 S7 0 2.6E-04 -1.5E-05 2.1E-06 0.0E+00 S8 0 1.2E-03 -5.9E-06 6.0E-06 0.0E+00 S14 0 -9.6E-05 2.4E-05 -2.7E-06 8.6E-07 S15 0 3.0E-04 -1.1E-04 4.1E-05 -3.5E-06

[0133] In this embodiment, fw=3.42mm, ft=6.84mm, ft / fw=2, fno=1.85~2.4, TTL=29.98mm;

[0134] Wherein, fw is the focal length of the zoom lens in wide-angle mode, ft is the focal length of the zoom lens in telephoto mode, fno is the aperture number of the zoom lens, and TTL is the total optical length of the zoom lens.

[0135] D8=3.62mm, D8 / fw=1.06;

[0136] Wherein, D8 is the thickness of the eighth lens L8 on the principal optical axis.

[0137] D8Imin=D8I=4.6mm, D8Imin / fw=1.35;

[0138] Wherein, D8I is the minimum distance between the eighth lens L8 and the image plane.

[0139] D12min=0.46mm, D12min / fw=0.13;

[0140] Wherein, D12min is the minimum distance between the first lens group G1 and the second lens group G2.

[0141] ΣXG2=0.21mm+0.1mm=0.31mm, ΣXG2 / fw=0.091;

[0142] Wherein, ΣXG2 is the sum of the distances between the second lens group G2.

[0143] S2=5.62mm, S2 / fw=1.64;

[0144] Wherein, S2 is the moving distance of the second lens group G2. Example

[0145] like Figures 8 to 14 As shown, a zoom lens, comprising, from the object plane side to the image plane side, the following components:

[0146] The first lens group G1 with negative optical power, the aperture stop STO, the second lens group G2 with positive optical power, the third lens group G3 with negative optical power, and the auxiliary component G4.

[0147] The first lens group G1, from the object plane side to the image plane side, includes the following:

[0148] A first lens L1 with negative optical power, a second lens L2 with negative optical power, and a third lens L3 with positive optical power.

[0149] The second lens group G2 includes, from the object plane side to the image plane side, the following:

[0150] The fourth lens L4 has positive optical power, the fifth lens L5 has positive optical power, the sixth lens L6 has negative optical power, and the seventh lens L7 has positive optical power.

[0151] The third lens group G3 is an eighth lens L8 with negative optical power;

[0152] The auxiliary component G4 includes, from the object plane side to the image plane side, the following components in sequence: a first protective glass CG1 and a second protective glass CG2.

[0153] The basic lens data of the zoom lens in this embodiment is shown in Table 4, the variable parameters in Table 4 are shown in Table 5, and the aspherical coefficients are shown in Table 6.

[0154] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0155] In Table 5, the WIDE column indicates the specific values ​​of each variable parameter when the zoom lens is in the wide-angle position, and the TELE column indicates the specific values ​​of each variable parameter when the zoom lens is in the telephoto position.

[0156] In Table 6, K is the conic coefficient, and e is the scientific notation, for example, e-005 represents 10. -5 .

[0157] Table 4

[0158] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 spherical 43.71 0.50 1.497 81.61 S2 spherical 3.80 2.45 S3 aspherical 21.75 0.49 1.531 55.77 S4 aspherical 4.27 0.23 S5 aspherical 9.12 1.90 1.661 20.38 S6 aspherical 34.71 D1 STO aspherical 5.17 3.18 1.535 56.09 S8 aspherical 9.97 0.10 S9 spherical 9.94 3.04 1.437 95.10 S10 spherical -3.47 1.19 1.805 25.46 S11 spherical -5.61 0.10 S12 spherical 32.38 1.95 1.437 95.10 S13 spherical -17.30 D2 S14 aspherical 12.55 3.56 1.635 23.98 S15 aspherical 9.63 D3 S16 spherical INF 0.30 1.517 64.20 S17 spherical INF 1.50 S18 spherical INF 0.50 1.517 64.20 S19 spherical INF 0.40 IMG

[0159] Table 5

[0160] WIDE TELE D1 6.27 0.5 D2 0.4 5.73 D3 1.92 2.36

[0161] Table 6

[0162] Quadratic surface constant (K) 4th order coefficients (A) 6th order coefficients (B) 8th order coefficients (C) 10th-order coefficients (D) S3 0 -1.8E-02 2.4E-03 -2.6E-04 3.7E-05 S4 0 -1.9E-02 2.5E-03 -6.5E-04 4.2E-05 S5 0 -5.5E-04 1.9E-05 -4.2E-06 -2.2E-07 S6 0 -7.1E-04 -2.1E-06 1.1E-05 -6.7E-07 S7 0 8.4E-05 -8.9E-06 2.0E-06 0.0E+00 S8 0 2.7E-03 -4.4E-07 5.6E-06 0.0E+00 S14 0 -7.9E-05 1.4E-05 -6.0E-06 7.6E-07 S15 0 -7.9E-05 1.4E-05 -6.0E-06 7.6E-07

[0163] In this embodiment, fw=3.5mm, ft=7.32mm, ft / fw=2.09, fno=1.85~2.52, TTL=29.98mm;

[0164] Wherein, fw is the focal length of the zoom lens in wide-angle mode, ft is the focal length of the zoom lens in telephoto mode, fno is the aperture number of the zoom lens, and TTL is the total optical length of the zoom lens.

[0165] D8=3.56mm, D8 / fw=1.02;

[0166] Wherein, D8 is the thickness of the eighth lens L8 on the principal optical axis.

[0167] D8Imin=4.62mm, D8Imin / fw=1.32;

[0168] Wherein, D8I is the minimum distance between the eighth lens L8 and the image plane.

[0169] D12min=0.5mm, D12min / fw=0.14;

[0170] Wherein, D12min is the minimum distance between the first lens group G1 and the second lens group G2.

[0171] ΣXG2=0.1mm+0.1mm=0.2mm, ΣXG2 / fw=0.057;

[0172] Wherein, ΣXG2 is the sum of the distances between the second lens group G2.

[0173] S2=5.77mm, S2 / fw=1.65;

[0174] Wherein, S2 is the moving distance of the second lens group G2. Example

[0175] like Figures 15 to 21 As shown, a zoom lens, comprising, from the object plane side to the image plane side, the following components:

[0176] The first lens group G1 with negative optical power, the aperture stop STO, the second lens group G2 with positive optical power, the third lens group G3 with negative optical power, and the auxiliary component G4.

[0177] The first lens group G1, from the object plane side to the image plane side, includes the following:

[0178] A first lens L1 with negative optical power, a second lens L2 with negative optical power, and a third lens L3 with positive optical power.

[0179] The second lens group G2 includes, from the object plane side to the image plane side, the following:

[0180] The fourth lens L4 has positive optical power, the fifth lens L5 has negative optical power, the sixth lens L6 has positive optical power, and the seventh lens L7 has positive optical power.

[0181] The third lens group G3 is an eighth lens L8 with negative optical power;

[0182] The auxiliary component G4 includes, from the object plane side to the image plane side, the following components in sequence: a first protective glass CG1 and a second protective glass CG2.

[0183] The basic lens data of the zoom lens in this embodiment is shown in Table 7, the variable parameters in Table 7 are shown in Table 8, and the aspherical coefficients are shown in Table 9.

[0184] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0185] In Table 8, the WIDE column indicates the specific values ​​of each variable parameter when the zoom lens is in the wide-angle position, and the TELE column indicates the specific values ​​of each variable parameter when the zoom lens is in the telephoto position.

[0186] In Table 9, K is the conic coefficient, and e is the scientific notation, for example, e-005 represents 10. -5 .

[0187] Table 7

[0188] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 spherical 27.35 0.50 1.497 81.61 S2 spherical 3.82 3.16 S3 aspherical 44.88 0.53 1.531 55.77 S4 aspherical 4.53 0.28 S5 aspherical 11.68 1.87 1.661 20.38 S6 aspherical 202.30 D1 STO aspherical 5.51 2.00 1.535 56.09 S8 aspherical 15.74 0.10 S9 spherical 13.29 1.77 1.805 25.46 S10 spherical 5.71 2.78 1.437 95.10 S11 spherical -8.19 0.18 S12 spherical 19.10 2.30 1.437 95.10 S13 spherical -10.88 D2 S14 aspherical 11.66 3.22 1.635 23.98 S15 aspherical 8.74 2.01 S16 spherical INF 0.30 1.517 64.20 S17 spherical INF 1.50 S18 spherical INF 0.50 1.517 64.20 S19 spherical INF 0.40 IMG

[0189] Table 8

[0190] WIDE TELE D1 6.19 0.5 D2 0.4 6.09

[0191] Table 9

[0192] Quadratic surface constant (K) 4th order coefficients (A) 6th order coefficients (B) 8th order coefficients (C) 10th-order coefficients (D) S3 0 -1.0E-02 3.5E-03 -3.7E-04 3.6E-05 S4 0 -1.4E-02 1.7E-03 -3.8E-04 7.2E-05 S5 0 -9.5E-05 2.4E-07 -4.0E-06 4.4E-07 S6 0 -3.7E-04 3.6E-06 1.9E-06 -3.1E-07 S7 0 2.5E-04 9.3E-06 5.8E-07 0.0E+00 S8 0 1.8E-03 3.0E-05 2.2E-06 0.0E+00 S14 0 -5.1E-05 4.1E-05 -5.6E-06 5.8E-07 S15 0 3.2E-04 -4.9E-05 4.3E-05 -7.5E-06

[0193] In this embodiment, fw=3.41mm, ft=6.82mm, ft / fw=2, fno=1.83~2.4, TTL=29.99mm;

[0194] Wherein, fw is the focal length of the zoom lens in wide-angle mode, ft is the focal length of the zoom lens in telephoto mode, fno is the aperture number of the zoom lens, and TTL is the total optical length of the zoom lens.

[0195] D8=3.22mm, D8 / fw=0.94;

[0196] Wherein, D8 is the thickness of the eighth lens L8 on the principal optical axis.

[0197] D8Imin=4.71mm, D8Imin / fw=1.38;

[0198] Wherein, D8I is the minimum distance between the eighth lens L8 and the image plane.

[0199] D12min=0.5mm, D12min / fw=0.15;

[0200] Wherein, D12min is the minimum distance between the first lens group G1 and the second lens group G2.

[0201] ΣXG2=0.1mm+0.18mm=0.28mm, ΣXG2 / fw=0.082;

[0202] Wherein, ΣXG2 is the sum of the distances between the second lens group G2.

[0203] S2=5.69mm, S2 / fw=1.67;

[0204] Wherein, S2 is the moving distance of the second lens group G2. Example

[0205] like Figures 1 to 21 As shown, an imaging device includes: a zoom lens as described in any of the above embodiments, and an imaging element configured to receive an image formed by the zoom lens.

[0206] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A zoom lens, characterized in that, The zoom lens consists of a first lens group with negative optical power, an aperture, a second lens group with positive optical power, and a third lens group with negative optical power, arranged sequentially from the object plane side to the image plane side. The second lens group moves along the direction of the principal optical axis; The first lens group consists of a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power, arranged sequentially from the object plane side to the image plane side. The second lens group consists of a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, and a seventh lens with positive optical power, in sequence from the object plane side to the image plane side; or the second lens group consists of a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with positive optical power, in sequence from the object plane side to the image plane side. The zoom lens includes at least three aspherical lenses; The aperture stop is disposed on the object plane side of the fourth lens; The image plane side of the fourth lens is bent toward the object plane side; The third lens group is an eighth lens with negative optical power; Both curved surfaces of the eighth lens are bent toward the object surface; The eighth lens satisfies the following condition: D8 / fw > 1; 1.8 < ft / fw < 2.2; Wherein, D8 is the thickness of the eighth lens on the principal optical axis, fw is the focal length of the zoom lens in wide-angle mode, and ft is the focal length of the zoom lens in telephoto mode.

2. A zoom lens according to claim 1, characterized in that: The eighth lens moves along the direction of the principal optical axis; The zoom lens satisfies the following condition: D8Imin / fw > 1.2; Wherein, D8Imin is the minimum distance between the eighth lens and the image plane.

3. A zoom lens according to claim 1 or 2, characterized in that: The third lens group includes at least two protective glasses between itself and the image plane.

4. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: D12min / fw < 0.2; Wherein, D12min is the minimum distance between the first lens group and the second lens group.

5. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: ΣXG2 / fw<0.1; Wherein, ΣXG2 is the sum of the distances between the second lens groups.

6. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: 1.5 < S² / fw < 1.8; Wherein, S2 is the moving distance of the second lens group.

7. An imaging device, characterized in that, include: The zoom lens as described in any one of claims 1 to 6; And an imaging element, configured to receive an image formed by the zoom lens.

Images