Zoom lens

Abstract

The present invention relates to a zoom lens, comprising a first fixed lens group with positive focal power, a zoom lens group with negative focal power, an aperture stop, a second fixed lens group with positive focal power, a focus lens group with positive focal power, and a third fixed lens group with positive focal power, which are arranged in sequence from the object side to the image side along the optical axis, wherein both the zoom lens group and the focus lens group can move along the optical axis, and the focus lens group consists of three lenses. Under the premise that the zoom lens ratio and the front port diameter and the total length of the lens are mutually restricted, the present invention can still achieve a large angle, a small volume, and low distortion, and can also achieve high resolution in the entire zoom stroke and 4K imaging in the full focal length range.

Description

Technical Field

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

[0002] The telephoto resolution of existing high-magnification zoom lenses is mostly at the 2M or 4M level. Moreover, the zoom ratio of the zoom lens is mutually restricted by the front diameter and total length of the lens, making it difficult to achieve miniaturization, large angles, and low distortion at the same time. In addition, it is difficult to achieve low cost by using glass aspherical surfaces to ensure lens resolution.

[0003] Chinese patent CN112305731A discloses a zoom lens. The lens contains a total of 18 lenses and adopts a five-group architecture design to meet the performance requirements of high magnification, large aperture, and large target surface, and achieve full-focal-length 4K imaging. However, the lens does not solve the problem that the zoom lens magnification ratio is constrained by the front diameter and total length of the lens, making it difficult to achieve miniaturization. Summary of the invention

[0004] In order to remedy the above defects, the object of the present invention is to provide a zoom lens which is small in size and has high resolution and high and low temperature image distortion-free performance.

[0005] To achieve the above-mentioned object, the present invention provides a zoom lens, comprising: a first fixed lens group with positive optical power, a zoom lens group with negative optical power, an aperture stop, a second fixed lens group with positive optical power, a focus lens group with positive optical power, and a third fixed lens group with positive optical power, which are arranged in sequence from the object side to the image side along the optical axis. The zoom lens group and the focus lens group can both move along the optical axis, and the focus lens group consists of three lenses.

[0006] According to one aspect of the present invention, the focal length FG1 of the first fixed lens group satisfies: 1.4≤FG1 / FW≤3.6;

[0007] Wherein, FW is the focal length of the zoom lens at the wide-angle end.

[0008] According to one aspect of the present invention, the focal length FG2 of the zoom lens group satisfies: -1.5≤FG2 / FW≤-0.5.

[0009] According to one aspect of the present invention, the focal length FG3 of the second fixed lens group satisfies: 1.1≤FG3 / FW≤2.6.

[0010] According to one aspect of the present invention, the focal length FG4 of the focus lens group satisfies: 1.3≤FG4 / FW≤3.8.

[0011] According to one aspect of the present invention, the focal length FG5 of the third fixed lens group satisfies: 7.3≤FG5 / FW≤14.1.

[0012] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0013] The first fixed lens group includes, in sequence, a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power;

[0014] The first lens and the third lens are both convex-concave lenses, and the second lens is a convex-convex lens;

[0015] The first lens and the second lens are cemented together to form a cemented lens group.

[0016] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0017] The zoom lens group includes, in sequence, a fourth lens having negative optical power, a fifth lens having negative optical power, a sixth lens having positive optical power, and a seventh lens having negative optical power;

[0018] The fourth lens is a convex-concave lens, the fifth lens is a concave-concave lens, the sixth lens is a convex-convex lens, and the shape of the seventh lens in the paraxial region is concave-concave;

[0019] The fifth lens and the sixth lens are cemented together to form a cemented lens group.

[0020] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0021] The second fixed lens group includes, in sequence, an eighth lens having positive optical power, a ninth lens having positive optical power, a tenth lens having positive or negative optical power, and an eleventh lens having positive or negative optical power;

[0022] The eighth lens is a convex-concave lens, and the ninth lens is a convex-convex lens.

[0023] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0024] The focusing lens group includes, in sequence, a twelfth lens having a positive optical power, a thirteenth lens having a positive optical power, and a fourteenth lens having a negative optical power;

[0025] The twelfth lens and the thirteenth lens are both convex-convex lenses, and the fourteenth lens is a concave-concave lens;

[0026] The thirteenth lens and the fourteenth lens are cemented together to form a cemented lens group.

[0027] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0028] The third fixed lens group sequentially includes a fifteenth lens with positive or negative optical power and a sixteenth lens with positive or negative optical power.

[0029] According to one aspect of the present invention, among the lenses included in the zoom lens group, the second fixed lens group and the third fixed lens group, there are at least three plastic aspherical lenses.

[0030] According to one aspect of the present invention, the travel D2 of the zoom lens group and the total length TTL of the zoom lens satisfy the relationship: 0.14≤|D2 / TTL|≤0.28.

[0031] According to one aspect of the present invention, the stroke D4 of the focus lens group and the stroke D2 of the zoom lens group satisfy the relationship: 0.35≤|D4 / D2|≤0.50.

[0032] According to one aspect of the present invention, the Abbe number Vb4 of the fourth lens satisfies the relationship: 15≤Vb4≤30.

[0033] According to one aspect of the present invention, the focal length FG2 of the zoom lens group and the focal length FG4 of the focus lens group satisfy the relationship: -0.50≤FG2 / FG4≤-0.30.

[0034] According to one aspect of the present invention, the maximum lens diameter ΦG1 of the first fixed group and the total length TTL of the zoom lens satisfy the relationship: 0.20≤ΦG1 / TTL≤0.40.

[0035] According to one aspect of the present invention, the lens has at least three cemented lens groups.

[0036] According to the solution of the present invention, a zoom lens applicable to video conferencing is provided. The lens can achieve high resolution in the entire zoom range while achieving wide angle, low distortion and small size, and can achieve 4K imaging at full focal length, which can clearly highlight target people and objects, ensure image clarity and flawless details, and restore the image realistically. The lens can be applied to real-time video interaction and can be widely used in various scenarios such as education, medical treatment, and government agencies.

[0037] According to one solution of the present invention, a five-group architecture with an optical focal length of "positive-negative-positive-positive-positive" consisting of a first fixed lens group, a zoom lens group, a second fixed lens group, a focus lens group and a third fixed lens group is adopted. This solves the contradiction between the mutually restrictive relationship between the zoom lens magnification ratio and the front port diameter and the total length of the lens and the miniaturization, large angle and low distortion of the lens. It can achieve short focal length and outstanding depth of field, meet the performance requirements of large angle, small size and low distortion, and realize 4K imaging of the entire focal length.

[0038] According to one solution of the present invention, through reasonable distribution of optical focal length and selection of specific glass materials, the difference between thermal characteristics of optical materials is utilized to eliminate the influence of temperature on the performance of the optical system within a wide temperature range of -40°C to 80°C, thereby maintaining stable image quality and preventing false focus. This enables 4K resolution imaging within the full focal length, stable image quality, and high definition.

[0039] According to one aspect of the present invention, by properly using a lens made of a plastic aspherical material, the cost of a zoom lens can be reduced.

[0040] According to one solution of the present invention, by adjusting the movement of the zoom lens group and the focus lens group, the proportion of the zoom lens group stroke in the total lens length and the stroke ratio of the focus lens group and the zoom lens group are respectively within a certain range, so that the zoom lens can quickly respond to the zoom-focus function. While having good autofocus and fast zoom functions, the image is delicate.

[0041] According to one solution of the present invention, by adjusting the maximum lens diameter in the first fixed group and making its proportion in the total length of the lens within a certain range, the size of the lens can be reduced to meet actual application requirements.

[0042] According to one solution of the present invention, system chromatic aberration can be corrected by properly using and adjusting the dispersion coefficient of the lens in the zoom lens.

[0043] According to one solution of the present invention, by reasonably setting and adjusting the focal length ranges of the zoom lens group and the focus lens group, the tolerance sensitivity of the zoom group, the focus group and the overall optical system of the lens can be adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic diagram schematically showing the structure of a zoom lens according to a first embodiment of the present invention;

[0045] Figure 2 The MTF diagram of the zoom lens at the wide-angle end according to the first embodiment of the present invention is schematically shown;

[0046] Figure 3Schematically showing the MTF diagram of the zoom lens at the telephoto end according to the first embodiment of the present invention;

[0047] Figure 4 A schematic diagram showing a defocus curve of a zoom lens according to a first embodiment of the present invention at a wide angle end of -40°C;

[0048] Figure 5 A diagram schematically showing a defocus curve of a zoom lens according to a first embodiment of the present invention at a wide angle end of 80°;

[0049] Figure 6 A schematic diagram showing a defocus curve of a zoom lens according to a first embodiment of the present invention at a telephoto end of -40°C;

[0050] Figure 7 A schematic diagram showing a defocus curve of a zoom lens at a telephoto end of 80° according to a first embodiment of the present invention;

[0051] Figure 8 A schematic diagram schematically showing the structure of a zoom lens according to a second embodiment of the present invention;

[0052] Fig. 9 The MTF diagram of the zoom lens at the wide-angle end according to the second embodiment of the present invention is schematically shown;

[0053] Fig.10 Schematically showing the MTF diagram of the zoom lens at the telephoto end according to the second embodiment of the present invention;

[0054] Fig.11 A diagram schematically showing a defocus curve of a zoom lens according to a second embodiment of the present invention at a wide angle end of -40°C;

[0055] Fig.12 A diagram schematically showing a defocus curve of a zoom lens according to a second embodiment of the present invention at a wide angle end of 80°;

[0056] Fig.13 A diagram schematically showing a defocus curve of a zoom lens according to a second embodiment of the present invention at a telephoto end of -40°C;

[0057] Fig.14 A diagram schematically showing a defocus curve of a zoom lens according to a second embodiment of the present invention at a telephoto end of 80°;

[0058] Fig.15 A schematic diagram schematically showing the structure of a zoom lens according to a third embodiment of the present invention;

[0059] Fig.16 Schematically showing the MTF diagram of the zoom lens at the wide-angle end according to the third embodiment of the present invention;

[0060] Fig.17Schematically showing the MTF diagram of the zoom lens at the telephoto end according to the third embodiment of the present invention;

[0061] Fig.18 A diagram schematically showing a defocus curve of a zoom lens according to a third embodiment of the present invention at a wide angle end of -40°C;

[0062] Fig.19 A diagram schematically showing a defocus curve of a zoom lens according to a third embodiment of the present invention at a wide angle end of 80°;

[0063] Fig. 20 A diagram schematically showing a defocus curve of a zoom lens according to a third embodiment of the present invention at a telephoto end of -40°C;

[0064] Fig.21 The defocus curve of the zoom lens system according to the third embodiment of the present invention at the telephoto end of 80° is schematically shown. DETAILED DESCRIPTION

[0065] 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 are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0066] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0067] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0068] See also Figure 1 The zoom lens of the present invention comprises a first fixed lens group G1 with positive power, a zoom lens group G2 with negative power, an aperture stop STO, a second fixed lens group G3 with positive power, a focus lens group G4 with positive power, and a third fixed lens group G5 with positive power, which are arranged in sequence from the object side to the image side along the optical axis. The focus lens group G4 consists of three lenses, which are respectively Figure 1The twelfth lens L12, the thirteenth lens L13 and the fourteenth lens L14 are shown. The above five-group architecture includes a total of 16 lenses. Among them, the optical focal length of the first fixed lens group G1 is positive, and the optical focal length of the zoom lens group G2 is negative, so as to achieve a large angle and a large zoom ratio. The zoom lens group G2 can move along the optical axis and is used for the optical zoom of the zoom lens between the wide-angle end and the telephoto end. The focus lens group G4 can also move along the optical axis to compensate for the change of the image plane position during the optical zoom process.

[0069] Through the above setting, five lens groups with optical focal powers of positive, negative, positive, positive and positive are used, which solves the contradiction between the mutual restriction relationship between the zoom lens magnification ratio and the front port diameter and the total length of the lens and the miniaturization, large angle and low distortion of the lens. Short focal length and outstanding depth of field can be achieved, meeting the performance requirements of large angle, small size and low distortion.

[0070] In the present invention, the focal length FG1 of the first fixed lens group G1 satisfies: 1.4≤FG1 / FW≤3.6; the focal length FG2 of the zoom lens group G2 satisfies: -1.5≤FG2 / FW≤-0.5; the focal length FG3 of the second fixed lens group G3 satisfies: 1.1≤FG3 / FW≤2.6; the focal length FG4 of the focus lens group G4 satisfies: 1.3≤FG4 / FW≤3.8; the focal length FG5 of the third fixed lens group G5 satisfies: 7.3≤FG5 / FW≤14.1. Wherein, FW is the focal length of the zoom lens at the wide angle end. Five lens groups are used with optical focal powers of positive, negative, positive, positive and positive, respectively. By setting the ratio range between the focal length of each lens group and the focal length of the zoom lens at the wide-angle end, while the zoom lens group G2 moves on the optical axis to achieve zooming, the focus lens group G4 can compensate for the aberration by moving on the optical axis, so that the aberration is well corrected and 4K imaging of the full focal length is achieved.

[0071] In the present invention, along the direction from the object side to the image side of the optical axis, the first fixed lens group G1 includes in sequence a first lens L1 having negative power, a second lens L2 having positive power, and a third lens L3 having positive power; wherein the first lens L1 and the third lens L3 are both convex-concave lenses, and the second lens L2 is a convex-convex lens. The zoom lens group G2 includes in sequence a fourth lens L4 having negative power, a fifth lens L5 having negative power, a sixth lens L6 having positive power, and a seventh lens L7 having negative power; wherein the fourth lens L4 is a convex-concave lens, the fifth lens L5 is a concave-concave lens, the sixth lens L6 is a convex-convex lens, and the shape of the seventh lens L7 in the paraxial region is concave-concave. The second fixed lens group G3 includes, in sequence, an eighth lens L8 having positive power, a ninth lens L9 having positive power, a tenth lens L10 having positive or negative power, and an eleventh lens L11 having positive or negative power; wherein the eighth lens L8 is a convex-concave lens, and the ninth lens L9 is a convex-convex lens. The focusing lens group G4 includes, in sequence, a twelfth lens L12 having positive power, a thirteenth lens L13 having positive power, and a fourteenth lens L14 having negative power; wherein the twelfth lens L12 and the thirteenth lens L13 are both convex-convex lenses, and the fourteenth lens L14 is a concave-concave lens. The third fixed lens group G5 includes, in sequence, a fifteenth lens L15 having positive or negative power, and a sixteenth lens L16 having positive or negative power.

[0072] The first lens L1 and the second lens L2 are cemented to form a cemented lens group, the fifth lens L5 and the sixth lens L6 are cemented to form a cemented lens group, and the thirteenth lens L13 and the fourteenth lens L14 are also cemented to form a cemented lens group. The lens has at least the above three cemented lens groups. Figure 1 As shown, the first fixed lens group G1 uses a cemented lens group and a single lens in combination, and the cemented surface is bent toward the aperture stop STO, which not only makes the first auxiliary light have a good direction, but also can correct the spherical aberration at the high-power position. The use of a cemented lens group can eliminate the chromatic aberration of the imaging part with good effect.

[0073] In the present invention, among the lenses included in the zoom lens group G2, the second fixed lens group G3 and the third fixed lens group G5, there are at least 3 plastic aspherical lenses, and the remaining lenses are glass spherical lenses. By selecting and reasonably distributing specific glass materials, utilizing the differences between the thermal properties of optical materials, and coordinating with the above-mentioned optical focal length settings, the influence of temperature on the performance of the optical system is eliminated within a large temperature range of -40°C to 80°C, thereby maintaining image quality stability and non-defocusing, so that 4K resolution imaging is satisfied within the full focal length, and the image quality is stable and high-definition. In addition, by mixing lenses made of plastic materials, the zoom function or compensation function of the lens group can be adjusted, thereby achieving lightweight zoom lens lenses and greatly reducing costs. At least three cemented lens groups in the present invention are matched with the above-mentioned lens materials to further correct the secondary spectral chromatic aberration of the zoom lens.

[0074] In the present invention, the stroke D2 of the zoom lens group G2 and the total length TTL of the zoom lens satisfy the relationship: 0.14≤|D2 / TTL|≤0.28. The stroke D4 of the focus lens group G4 and the stroke D2 of the zoom lens group G2 satisfy the relationship: 0.35≤|D4 / D2|≤0.50. By adjusting the actions of the zoom lens group and the focus lens group, the stroke ratio of the zoom lens group in the lens and the stroke ratio of the focus lens group to the zoom lens group are changed, so that the zoom lens quickly responds to the zoom-focus function.

[0075] In the present invention, the Abbe number Vb4 of the fourth lens L4 satisfies the relationship: 15≤Vb4≤30. By properly using and adjusting the dispersion coefficient of the lens, the chromatic aberration of the lens can be corrected.

[0076] In the present invention, the focal length FG2 of the zoom lens group G2 and the focal length FG4 of the focus lens group G4 satisfy the relationship: -0.50≤FG2 / FG4≤-0.30. This design can adjust the tolerance sensitivity of the zoom group, focus group and the overall optical system of the zoom lens.

[0077] In the present invention, the maximum lens diameter ΦG1 of the first fixed group G1 and the total length TTL of the zoom lens satisfy the relationship: 0.20≤ΦG1 / TTL≤0.40. By adjusting the maximum lens diameter in the first fixed group and making it account for the total length of the lens within a certain range, the zoom lens can be kept small while the zoom ratio of the lens is mutually restricted with the front diameter and the total length of the lens, meeting the actual application requirements of real-time video interaction, and can be widely used in various scenarios such as education, medical treatment, and government agencies.

[0078] In summary, the present invention adopts a five-group architecture with an optical power of "positive-negative-positive-positive-positive", which includes a total of 16 lenses to achieve large angles and low distortion. In addition, the cemented lens group is reasonably arranged and the lens material is reasonably allocated, so that the aberration can be well corrected and the secondary spectral chromatic aberration can be corrected. By reasonably allocating the focal length of each lens group, 4K high-resolution imaging of the entire focal length range can be achieved. By reasonably matching and using lenses made of glass and plastic materials, the influence of temperature on the performance of the optical system can be eliminated within a large temperature range of -40°C to 80°C, thereby maintaining the stability of the image quality and preventing out-of-focus, and also achieving lightweight and small size of the lens, effectively reducing costs.

[0079] The zoom lens of the present invention is described in detail below using three groups of specific embodiments. In each of the following specific embodiments, the object plane is denoted as OBJ, the image plane is denoted as IMA, and the cemented surface of the cemented lens group is denoted as one surface.

[0080] The parameters of each specific implementation method that specifically meets the above conditional formula are shown in Table 1 below:

[0081]

[0082] Table 1

[0083] In the present invention, the aspherical lens of the zoom lens satisfies the following formula:

[0084]

[0085] In the above formula, z is the axial distance from the surface to the vertex at a height h perpendicular to the optical axis along the optical axis; c represents the curvature at the vertex of the aspheric surface; k is the cone coefficient; A4, A6, A8, A 10 , A 12 , A 14 , A 16 ···represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, sixteenth-order···aspheric coefficients respectively.

[0086] First specific implementation method

[0087] See also Figures 1 to 7 In this embodiment, the zoom lens uses a total of 16 lenses, including 3 plastic aspherical lenses. 4 cemented lens groups are used, such as Figure 1 As shown, it is a cemented lens group composed of the first lens L1 and the second lens L2, the fifth lens L5 and the sixth lens L6, the tenth lens L10 and the eleventh lens L11, and the thirteenth lens L13 and the fourteenth lens L14.

[0088] The parameters of each lens of the zoom lens of this embodiment include surface type, curvature radius (R value), thickness, refractive index of the material, and Abbe number, as shown in Table 2 below:

[0089]

[0090]

[0091] Table 2

[0092] The aspheric coefficients of each aspheric lens of the zoom lens of this embodiment include the quadratic surface constant 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, and the twelfth-order aspheric coefficient E of the surface, as shown in Table 3 below.

[0093] Surface number K A B C D E S11 1.539331 -1.002E-004 2.3482E-005 -8.230E-007 3.7804E-008 -1.861E-009 S12 -30.030907 -3.912E-004 1.3023E-005 -2.693E-007 -1.403E-008 6.9158E-010 S14 0.749365 -7.066E-005 2.5207E-006 -8.561E-008 8.7377E-009 3.9594E-010 S15 25.517627 1.5455E-004 3.8363E-006 -9.776E-008 9.9321E-009 2.2465E-010 S28 -26.947966 -4.671E-003 2.6670E-004 -1.133E-005 1.8127E-007 -2.037E-008 S29 1.823440 -5.570E-003 2.6779E-004 -2.089E-005 5.7053E-007 -5.899E-008

[0094] Table 3

[0095] The zoom data at the wide-angle end and the telephoto end of the zoom lens of this embodiment are shown in Table 4 below.

[0096] Wide-angle end Telephoto T1 0.52 9.97 T2 9.86 0.41 T3 5.25 2.94 T4 1.57 3.88

[0097] Table 4

[0098] Combination Figures 1 to 7 It can be seen that the present embodiment can correct the position chromatic aberration and magnification chromatic aberration between 420 and 680 nm through the above settings, and the purple edge is small. By rationally constructing the optical architecture, using plastic aspherical lenses, and rationally allocating the optical power of different lenses, wide-angle, low distortion, and miniaturization performance are achieved, ensuring 4K clear imaging at the full focal length.

[0099] Second specific implementation method

[0100] See also Figures 8 to 14 In this embodiment, the zoom lens uses a total of 16 lenses, of which 4 are plastic aspherical lenses. Three cemented lens groups are used, such as Figure 8 As shown, it is a cemented lens group formed by the first lens L1 and the second lens L2, the fifth lens L5 and the sixth lens L6, and the thirteenth lens L13 and the fourteenth lens L14.

[0101] The parameters of each lens of the zoom lens of this embodiment include surface type, curvature radius (R value), thickness, refractive index of the material, and Abbe number, as shown in Table 5 below:

[0102]

[0103]

[0104] Table 5

[0105] The aspheric coefficients of each aspheric lens of the zoom lens of this embodiment include the quadratic surface constant 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, and the twelfth-order aspheric coefficient E of the surface, as shown in Table 6 below.

[0106] Surface number K A B C D E S11 3.097128 -1.957E-004 1.1335E-005 -1.502E-006 7.2183E-008 1.8880E-008 S12 97.162591 -3.272E-004 2.0504E-005 -1.760E-008 -8.598E-008 -2.399E-008 S14 0.617139 -1.183E-004 2.1026E-006 -7.797E-008 9.3170E-009 4.1979E-010 S15 25.516279 2.0317E-004 4.6802E-006 -8.465E-008 1.0445E-008 2.6057E-010 S27 20.788245 3.0562E-004 1.1465E-005 4.849E-008 -7.8461E-008 -5.8462E-010 S28 16.785549 1.8524E-004 2.1482E-005 2.965E-008 -8.4715E-008 -6.7428E-010 S29 28.728346 -4.219E-003 3.7576E-004 -7.832E-006 9.9542E-008 -5.310E-008 S30 -30.713394 -6.000E-003 2.2489E-004 -2.040E-005 8.0573E-007 -2.992E-008

[0107] Table 6

[0108] The zoom data at the wide-angle end and the telephoto end of the zoom lens of this embodiment are shown in Table 7 below.

[0109] Wide-angle end Telephoto T1 0.44 9.59 T2 9.74 0.59 T3 5.34 2.85 T4 1.66 4.15

[0110] Table 7

[0111] Combination Figures 8 to 14 It can be seen that, through the above settings, this embodiment can correct the position chromatic aberration and magnification chromatic aberration between 420 and 680 nm, with small purple fringing, and can also meet the 4K resolution of the full focal length. By setting a lens combination with different structures and reasonably allocating the focal length of each lens, reducing vignetting or not setting vignetting, low distortion and high relative illumination of the zoom lens are achieved while obtaining high-definition resolution.

[0112] The third specific implementation method

[0113] See also Figures 15 to 21 In this embodiment, the zoom lens uses a total of 16 lenses, including 3 plastic aspherical lenses. Fig.15 As shown, it is a cemented lens group formed by the first lens L1 and the second lens L2, the fifth lens L5 and the sixth lens L6, and the thirteenth lens L13 and the fourteenth lens L14.

[0114] The parameters of each lens of the zoom lens of this embodiment include surface type, curvature radius (R value), thickness, refractive index of the material, and Abbe number, as shown in Table 8 below:

[0115]

[0116]

[0117] Table 8

[0118] The aspheric coefficients of each aspheric lens of the zoom lens of this embodiment include the quadratic surface constant 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, and the twelfth-order aspheric coefficient E of the surface, as shown in Table 9 below.

[0119]

[0120]

[0121] Table 9

[0122] The zoom data at the wide-angle end and the telephoto end of the zoom lens of this embodiment are shown in Table 10 below.

[0123] Wide-angle end Telephoto T1 0.68 9.64 T2 9.53 0.57 T3 5.42 2.56 T4 1.51 4.37

[0124] Table 10

[0125] Combination Figures 15 to 21 It can be seen that, through the above settings, this embodiment can correct the position chromatic aberration and magnification chromatic aberration between 420 and 680 nm, with small purple fringing, and meet the 4K resolution of the full focal length. Reasonable distribution of optical power can better correct aberrations such as spherical aberration and field curvature, and improve the resolution of the zoom lens.

[0126] The above is only one embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A zoom lens, comprising: A total of five lens groups are arranged in sequence from the object side to the image side along the optical axis, namely, a first fixed lens group (G1) with positive focal power, a zoom lens group (G2) with negative focal power, an aperture stop (STO), a second fixed lens group (G3) with positive focal power, a focus lens group (G4) with positive focal power, and a third fixed lens group (G5) with positive focal power. Both the zoom lens group (G2) and the focus lens group (G4) can move along the optical axis, and the focus lens group (G4) is characterized in that the focus lens group (G4) consists of three lenses; Along the direction from the object side to the image side of the optical axis, the zoom lens group (G2) comprises a total of four lenses, namely, a fourth lens (L4) with negative optical focal power, a fifth lens (L5) with negative optical focal power, a sixth lens (L6) with positive optical focal power, and a seventh lens (L7) with negative optical focal power; the fourth lens (L4) is a convexo-concave lens, the fifth lens (L5) is a concave-concave lens, the sixth lens (L6) is a convexo-convex lens, and the shape of the seventh lens (L7) in the paraxial region is concave-concave; Along the direction from the object side to the image side of the optical axis, the focusing lens group (G4) sequentially includes a twelfth lens (L12) with positive optical power, a thirteenth lens (L13) with positive optical power, and a fourteenth lens (L14) with negative optical power.

2. The zoom lens according to claim 1, wherein: The focal length FG1 of the first fixed lens group (G1) satisfies: 1.4≤FG1 / FW≤3.6; Wherein, FW is the focal length of the zoom lens at the wide-angle end.

3. The zoom lens according to claim 1, wherein: The focal length FG2 of the zoom lens group (G2) satisfies: -1.5≤FG2 / FW≤-0.5; Wherein, FW is the focal length of the zoom lens at the wide-angle end.

4. The zoom lens according to claim 1, wherein: The focal length FG3 of the second fixed lens group (G3) satisfies: 1.1≤FG3 / FW≤2.6; Wherein, FW is the focal length of the zoom lens at the wide-angle end.

5. The zoom lens according to claim 1, wherein: The focal length FG4 of the focus lens group (G4) satisfies: 1.3≤FG4 / FW≤3.8; Wherein, FW is the focal length of the zoom lens at the wide-angle end.

6. The zoom lens according to claim 1, wherein: The focal length FG5 of the third fixed lens group (G5) satisfies: 7.3≤FG5 / FW≤14.1; Wherein, FW is the focal length of the zoom lens at the wide-angle end.

7. The zoom lens according to claim 1, wherein: Along the direction from the object side to the image side of the optical axis, The first fixed lens group (G1) comprises in sequence a first lens (L1) with negative optical power, a second lens (L2) with positive optical power, and a third lens (L3) with positive optical power.

8. The zoom lens according to claim 7, wherein: Along the direction from the object side to the image side of the optical axis, the first lens (L1) and the third lens (L3) are both convex-concave lenses, and the second lens (L2) is a convex-convex lens.

9. The zoom lens according to claim 8, wherein: The first lens (L1) and the second lens (L2) are glued together to form a glued lens group.

10. The zoom lens according to claim 1, wherein: The fifth lens (L5) and the sixth lens (L6) are cemented together to form a cemented lens group.

11. The zoom lens according to claim 1, wherein: Along the direction from the object side to the image side of the optical axis, The second fixed lens group (G3) comprises, in sequence, an eighth lens (L8) with positive optical power, a ninth lens (L9) with positive optical power, a tenth lens (L10) with positive or negative optical power, and an eleventh lens (L11) with positive or negative optical power.

12. The zoom lens according to claim 11, wherein: Along the direction from the object side to the image side of the optical axis, the eighth lens (L8) is a convex-concave lens, and the ninth lens (L9) is a convex-convex lens.

13. The zoom lens according to claim 1, wherein: Along the direction from the object side to the image side of the optical axis, the twelfth lens (L12) and the thirteenth lens (L13) are both convex-convex lenses, and the fourteenth lens (L14) is a concave-concave lens.

14. The zoom lens according to claim 13, wherein: The thirteenth lens (L13) and the fourteenth lens (L14) are cemented together to form a cemented lens group.

15. The zoom lens according to claim 1, wherein: Along the direction from the object side to the image side of the optical axis, The third fixed lens group (G5) sequentially includes a fifteenth lens (L15) with positive or negative optical power and a sixteenth lens (L16) with positive or negative optical power.

16. The zoom lens according to any one of claims 1 to 15, characterized in that: Among the lenses included in the zoom lens group (G2), the second fixed lens group (G3) and the third fixed lens group (G5), there are at least three plastic aspherical lenses.

17. The zoom lens according to any one of claims 1 to 15, characterized in that: The travel distance D2 of the zoom lens group (G2) and the total length TTL of the zoom lens satisfy the relationship: 0.14≤|D2 / TTL|≤0.

28.

18. The zoom lens according to any one of claims 1 to 15, characterized in that: The stroke D4 of the focus lens group (G4) and the stroke D2 of the zoom lens group (G2) satisfy the relationship: 0.35≤|D4 / D2|≤0.

50.

19. The zoom lens according to any one of claims 1 to 15, characterized in that: The Abbe number Vb4 of the fourth lens (L4) satisfies the relationship: 15≤Vb4≤30.

20. The zoom lens according to any one of claims 1 to 15, characterized in that: The focal length FG2 of the zoom lens group (G2) and the focal length FG4 of the focus lens group (G4) satisfy the relationship: -0.50≤FG2 / FG4≤-0.

30.

21. The zoom lens according to any one of claims 1 to 15, characterized in that: The maximum lens diameter ΦG1 of the first fixed lens group (G1) and the total length TTL of the zoom lens satisfy the relationship: 0.20≤ΦG1 / TTL≤0.

40.

22. The zoom lens according to any one of claims 1 to 15, characterized in that: The lens has at least three cemented lens groups.

Images