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, 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 feature is that the focal power of the third fixed lens group is negative. The zoom lens of the present invention realizes small size, large aperture, day and night confocality, no defocusing in high and low temperature environments, and realizes 4K high-resolution imaging of the full focal length. Plastic aspherical lenses are used to reduce costs.

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 high-end market of the security industry has higher and higher requirements for picture clarity, and 4K resolution has gradually become the mainstream. The telephoto end resolution of existing large-magnification zoom lenses is mostly at the 2M and 4M levels, which can no longer meet the market demand. Since the zoom ratio of the zoom lens is mutually restricted by the front diameter and total length of the lens, it is difficult to achieve miniaturization. If the zoom lens uses a large aperture, although it can ensure the capture of sufficient light in dark fields and at night, it often brings obvious aberrations and unclear imaging. In addition, the security field generally requires that the camera lens needs to have infrared confocal performance and the characteristics of no image distortion at high and low temperatures. In other words, the zoom system needs to take into account high resolution, infrared confocality, and no image distortion at high and low temperatures. In order to ensure the resolution of the lens, it is difficult to achieve low cost by using glass aspherical lenses.

[0003] In order to solve the above problems, the prior art CN201310185215.0 discloses a high-pixel macro focus large-magnification zoom optical system. The system is provided with the first, second, third, fourth and fifth lens groups from the object to the image plane, and the focal lengths thereof are positive, negative, positive, positive and positive, respectively. Among them, the first and third lens groups are fixed relative to the image plane, and the second, fourth and fifth lens groups can move forward and backward along the object-image direction relative to the image plane, and an aperture is provided between the second and third lens groups. The five lens groups contain a total of fifteen optical glass spherical lenses, and a filter is provided between the fifteenth lens and the image plane. Although this solution solves the problems of large volume and low resolution of the zoom optical system, the use of all glass spherical lenses makes the zoom optical system costly and heavy. In addition, it does not mention the performance of simultaneously satisfying infrared confocal and high and low temperature image distortion. 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 the performances of high resolution, infrared confocality and no distortion of high and low temperature images.

[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, which are arranged in sequence from the object side to the image side along the optical axis, wherein the zoom lens group and the focus lens group can both move along the optical axis, and the optical power of the third fixed lens group is negative.

[0006] According to one aspect of the present invention, the focal length FG1 of the first fixed lens group satisfies: 3≤FG1 / Fw≤5.5;

[0007] The focal length FG2 of the zoom lens group satisfies: -1.8≤FG2 / Fw≤-0.6;

[0008] The focal length FG3 of the second fixed lens group satisfies: 1≤FG3 / Fw≤2.8;

[0009] The focal length FG4 of the focus lens group satisfies: 1.5≤FG4 / Fw≤4;

[0010] The focal length FG5 of the third fixed lens group satisfies: FG5 / Fw≤-3;

[0011] Wherein, Fw is the focal length of the zoom lens at the wide-angle end.

[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 second lens are cemented together to form a cemented lens group.

[0015] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0016] The first lens and the third lens are convex-concave;

[0017] The second lens is of convex-convex type.

[0018] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0019] 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;

[0020] The fifth lens and the sixth lens are cemented together to form a cemented lens group.

[0021] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0022] The fourth lens is of convex-concave type;

[0023] The fifth lens is of concave-concave type;

[0024] The sixth lens is of convex-convex type;

[0025] The paraxial region of the seventh lens is convex-concave.

[0026] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0027] 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 negative optical power, an eleventh lens having negative optical power, a twelfth lens having positive optical power, and a thirteenth lens having negative optical power;

[0028] The eleventh lens and the twelfth lens or the eleventh lens, the twelfth lens and the thirteenth lens are cemented together to form a cemented lens group.

[0029] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0030] The eighth lens, the ninth lens and the twelfth lens are convex-convex type;

[0031] The tenth lens and the thirteenth lens are concave-concave type;

[0032] The eleventh lens is of convex-concave type.

[0033] According to one aspect of the present invention, the refractive indices Nd of the eighth lens, the ninth lens and the tenth lens all satisfy the relationship: Nd≤1.68.

[0034] According to one aspect of the present invention, the Abbe number Vb8 of the eighth lens satisfies the relationship: 60≤Vb8≤96.

[0035] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis, the focusing lens group sequentially includes a fourteenth lens with positive optical power, a fifteenth lens with negative optical power and a sixteenth lens with positive optical power.

[0036] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0037] The fourteenth lens is of convex-concave type;

[0038] The fifteenth lens and the sixteenth lens are concave-convex type.

[0039] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis, the third fixed lens group sequentially includes a seventeenth lens with positive optical power and an eighteenth lens with negative optical power.

[0040] According to one aspect of the present invention, along the direction from the object side to the image side of the optical axis,

[0041] The seventeenth lens is of concave-convex type;

[0042] The paraxial region of the eighteenth lens is of a concave-concave type.

[0043] According to one aspect of the present invention, at least three of the lenses included in the zoom lens are aspherical lenses; at least two of the aspherical lenses are made of plastic.

[0044] According to one aspect of the present invention, the zoom lens comprises lenses including at least three cemented lens groups formed by cementing adjacent lenses.

[0045] According to one aspect of the present invention, the target surface diameter φI covered by the zoom lens and the total length TTL of the zoom lens satisfy the relationship: 0.070≤φI / TTL≤0.110.

[0046] According to one aspect of the present invention, the absolute value D2 of the stroke of the zoom lens group and the total length TTL of the zoom lens satisfy the relationship: 0.3≤D2 / TTL≤0.4.

[0047] According to one aspect of the present invention, the absolute value D4 of the stroke of the focus lens group and the absolute value D2 of the stroke of the zoom lens group satisfy the relationship: 0≤D4 / D2≤0.2.

[0048] According to the solution of the present invention, a zoom lens is provided, which realizes small size, large aperture, large target surface, day and night confocality, no defocusing in high and low temperature environments, and full focal length meets 4K resolution. In addition, a plastic aspherical lens is used to achieve low cost.

[0049] According to one solution of the present invention, a five-group structure 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, so that the zoom lens can achieve a large target surface of φ9.1 and a maximum aperture of F1.4. At the same time, the focal length of the first fixed lens group is positive, and the focal length of the zoom lens group is negative, ensuring that light incident at large angles or large apertures can enter the rear lens group to achieve a larger zoom ratio. While meeting the performance requirements of large magnification, small size, large aperture and large target surface, full focal length 4K imaging can be achieved.

[0050] According to one solution of the present invention, through reasonable distribution of optical power and selection of specific glass materials, the zoom lens can achieve chromatic aberration and secondary spectral chromatic aberration correction between 380 and 940 nm at the telephoto end. Reasonable setting of the cemented lens group can meet the full focal range infrared confocal.

[0051] According to one solution of the present invention, by reasonably matching the refractive index temperature coefficients of specific materials of each lens, there is no out-of-focus and image distortion in the temperature range of -40°C to 80°C, and 4K high-resolution imaging is achieved at the full focal length.

[0052] According to one aspect of the present invention, the cost of a zoom lens can be reduced by properly using a plastic aspherical lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A schematic diagram schematically showing the structure of a zoom lens according to a first embodiment of the present invention;

[0054] 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;

[0055] Figure 3 Schematically showing the MTF diagram of the zoom lens at the telephoto end according to the first embodiment of the present invention;

[0056] Figure 4 A schematic diagram schematically showing the structure of a zoom lens according to a second embodiment of the present invention;

[0057] Figure 5 The MTF diagram of the zoom lens at the wide-angle end according to the second embodiment of the present invention is schematically shown;

[0058] Figure 6 Schematically showing the MTF diagram of the zoom lens at the telephoto end according to the second embodiment of the present invention;

[0059] Figure 7 A schematic diagram schematically showing the structure of a zoom lens according to a third embodiment of the present invention;

[0060] Figure 8 Schematically showing the MTF diagram of the zoom lens at the wide-angle end according to the third embodiment of the present invention;

[0061] Fig. 9 The MTF diagram of the zoom lens at the telephoto end according to the third embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0062] 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.

[0063] 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.

[0064] 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.

[0065] See also Figure 1 The zoom lens of the present invention comprises 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 negative focal power, which are arranged in sequence from the object side to the image side along the optical axis. The focal power of the first fixed lens group G1 is positive, and the focal power of the zoom lens group G2 is negative, so that light rays incident at large angles or large apertures can enter the rear lens group, thereby achieving a larger zoom ratio. The zoom lens group G2 can move along the optical axis to achieve optical zoom between the wide-angle end and the telephoto end of the zoom lens. The focus lens group G4 can also move along the optical axis to compensate for changes in the image plane position during the optical zoom process. During use, the focus lens group G4 is properly adjusted to offset the conjugate distance variation produced by the zoom lens group G2 when the object is far away and at a macro distance, so as to achieve image plane compensation and obtain a high-quality image.

[0066] In the present invention, the focal length FG1 of the first fixed lens group G1 satisfies: 3≤FG1 / Fw≤5.5; the focal length FG2 of the zoom lens group G2 satisfies: -1.8≤FG2 / Fw≤-0.6; the focal length FG3 of the second fixed lens group G3 satisfies: 1≤FG3 / Fw≤2.8; the focal length FG4 of the focus lens group G4 satisfies: 1.5≤FG4 / Fw≤4; the focal length FG5 of the third fixed lens group G5 satisfies: FG5 / Fw≤-3. Wherein, Fw is the focal length of the zoom lens at the wide angle end. By setting the ratio range between 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 aberrations by moving on the optical axis to achieve clear imaging.

[0067] 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 a first lens L1 with negative focal power, a second lens L2 with positive focal power, and a third lens L3 with positive focal power. The first lens L1 and the second lens L2 are cemented together to form a cemented lens group. The shapes of the first lens L1 and the third lens L3 are both convex-concave, and the shape of the second lens L2 is convex-convex. Figure 1 , Figure 4 and Figure 7 As shown, the first fixed lens group G1 is used in combination with a cemented lens group and a single lens, 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.

[0068] The zoom lens group G2 includes a fourth lens L4 with negative focal power, a fifth lens L5 with negative focal power, a sixth lens L6 with positive focal power, and a seventh lens L7 with negative focal power. The fifth lens L5 and the sixth lens L6 are cemented together to form a cemented lens group. The shape of the fourth lens L4 is convex-concave, the shape of the fifth lens L5 is concave-concave, the shape of the sixth lens L6 is convex-convex, and the shape of the paraxial area of ​​the seventh lens L7 is convex-concave.

[0069] The second fixed lens group G3 includes in sequence an eighth lens L8 with positive focal power, a ninth lens L9 with positive focal power, a tenth lens L10 with negative focal power, an eleventh lens L11 with negative focal power, a twelfth lens L12 with positive focal power, and a thirteenth lens L13 with negative focal power. Among them, the eleventh lens L11 and the twelfth lens L12 or the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are cemented to form a cemented lens group. The shapes of the eighth lens L8, the ninth lens L9 and the twelfth lens L12 are all convex-convex, the shapes of the tenth lens L10 and the thirteenth lens L13 are all concave-concave, and the shape of the eleventh lens L11 is convex-concave.

[0070] The focusing lens group G4 includes a fourteenth lens L14 with positive refractive power, a fifteenth lens L15 with negative refractive power, and a sixteenth lens L16 with positive refractive power. The fourteenth lens L14 is convex-concave, and the fifteenth lens L15 and the sixteenth lens L16 are both concave-convex.

[0071] The third fixed lens group G5 includes, in sequence, a seventeenth lens L17 with positive focal power and an eighteenth lens L18 with negative focal power. The shape of the seventeenth lens L17 is a concave-convex type, and the shape of the paraxial region of the eighteenth lens L18 is a concave-concave type. The present invention uses five lens groups with focal powers of positive, negative, positive, positive, and negative in sequence, and uses them in conjunction with different choices of the surface shapes of each lens in each lens group, so that aberrations are well corrected.

[0072] In the present invention, the refractive index Nd of the eighth lens L8, the ninth lens L9 and the tenth lens L10 all satisfy the relationship: Nd≤1.68. The Abbe number Vb8 of the eighth lens L8 satisfies the relationship: 60≤Vb8≤96. By selecting appropriate materials for the eighth lens L8, the ninth lens L9 and the tenth lens L10 in the second fixed lens group, the secondary spectral chromatic aberration can be corrected in coordination with the focal power and lens shape of the lens group of the present invention.

[0073] In the present invention, at least three of the lenses included in the zoom lens are aspheric lenses. At least two of the aspheric lenses are made of plastic. The present invention uses a mixture of plastic aspheric lenses and glass lenses to adjust the zoom function or compensation function of the lens group, thereby achieving lightweight lenses in the zoom lens and greatly reducing costs. At the same time, it is ensured that the zoom lens can still image clearly in high and low temperature environments and has good performance.

[0074] In the present invention, the zoom lens includes at least three glued lens groups formed by gluing adjacent lenses. The glued lens group can eliminate the chromatic aberration of the imaging part with good effect and realize infrared confocal. At the same time, it can further correct the secondary spectral chromatic aberration when matched with the lens material.

[0075] In the present invention, the target surface diameter φI covered by the zoom lens and the total length TTL of the zoom lens satisfy the relationship: 0.070≤φI / TTL≤0.110. This design can make the zoom lens small and light.

[0076] In the present invention, the absolute value D2 of the stroke of the zoom lens group G2 and the total length TTL of the zoom lens satisfy the relationship: 0.3≤D2 / TTL≤0.4. At the same time, the absolute value D4 of the stroke of the focus lens group G4 and the absolute value D2 of the stroke of the zoom lens group G2 satisfy the relationship: 0≤D4 / D2≤0.2. This allows the zoom lens to have a faster zoom and focus speed.

[0077] In summary, the present invention adopts a five-group architecture and reasonably allocates the positive and negative optical focal lengths, lens surface shapes and lens materials of lenses and lens groups, so that the aberrations can be well corrected and the secondary spectral chromatic aberration can be corrected. By reasonably allocating the focal lengths of each lens group, 4K high-resolution imaging of the full focal length segment can be achieved. By using a cemented lens group, the chromatic aberration and spherical aberration of the zoom lens can be eliminated or corrected to achieve infrared confocality in the full focal length segment. By reasonably matching the refractive index temperature coefficients of each lens glass material and plastic material, the zoom lens can be made non-defocused and the image non-distorted within a temperature range of -40°C to 80°C. By using plastic aspheric lenses, small size and low cost can be achieved.

[0078] The zoom lens of the present invention is specifically described below using three groups of embodiments. In each of the following embodiments, the image plane is denoted as IMA, and the cemented surface of the cemented lens group is denoted as one surface.

[0079] Parameters of various implementations that specifically meet the above conditional formula are shown in Table 1 below:

[0080]

[0081] Table 1

[0082] First Implementation Method

[0083] See also Figures 1 to 3 In this embodiment, the present invention uses a total of 18 lenses, of which four lenses are aspherical lenses, and the seventh lens L7, the fifteenth lens L15 and the eighteenth lens L18 are all plastic aspherical lenses. Three cemented lens groups are used, such as Figure 1 As shown, a cemented lens group is formed by cementing a first lens L1 and a second lens L2, a fifth lens L5 and a sixth lens L6, and an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13.

[0084] In this embodiment, the aperture F# is 1.6.

[0085] 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:

[0086]

[0087]

[0088] Table 2

[0089] 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.

[0090] Surface number K A B C D E S11 -1.51E-04 -6.11E-07 9.12E-09 -8.87E-11 7.48E-13 -1.51E-04 S12 -1.54E-04 -2.08E-07 1.27E-09 6.16E-11 -1.14E-12 -1.54E-04 S14 1.59E-05 1.40E-11 2.17E-10 -2.27E-12 9.08E-15 1.59E-05 S15 9.20E-06 -1.57E-08 1.85E-10 -1.34E-12 1.01E-14 9.20E-06 S26 -1.70E+01 -7.04E-05 1.19E-06 -4.10E-08 7.60E-10 -1.31E-11 S27 -4.60E-01 -6.02E-05 6.16E-07 -2.07E-08 4.44E-10 -1.84E-12 S32 -1.70E+01 -6.69E-04 9.82E-06 4.29E-08 -4.58E-09 2.78E-11 S33 -4.60E-01 -9.38E-04 8.96E-06 -7.63E-08 1.48E-09 -5.54E-11

[0091] Table 3

[0092] 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.

[0093]

[0094]

[0095] Table 4

[0096] Combination Figures 1 to 3 It can be seen that this embodiment can achieve a maximum aperture of F1.6, can correct the position chromatic aberration and magnification chromatic aberration between 380 and 940nm, and achieve 380-940nm confocal. In high and low temperature environments of -40℃ to 80℃, the zoom lens can still meet the full 4K resolution without refocusing. The zoom lens has a large aperture and a small size, and can be applied to more scenes with different conditions.

[0097] Second implementation method

[0098] See also Figures 4 to 6 In this embodiment, the present invention uses a total of 18 lenses, of which three lenses are aspherical lenses, and the seventh lens L7 and the eighteenth lens L18 are both plastic aspherical lenses. Four cemented lens groups are used, such as Figure 4 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 ninth lens L9 and the tenth lens L10, and the eleventh lens L11 and the twelfth lens L12.

[0099] In this embodiment, F#: 1.5.

[0100] 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:

[0101]

[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 0 -1.55E-04 -6.12E-07 8.97E-09 -1.06E-10 1.05E-12 S12 0 -1.54E-04 -2.16E-07 1.51E-09 8.51E-11 -1.16E-12 S14 -1.34741089 1.43E-05 1.45E-09 2.26E-10 -2.18E-12 9.42E-15 S15 -6.69538182 7.80E-06 -1.39E-08 1.80E-10 -1.38E-12 1.12E-14 S32 0 -7.03E-04 9.79E-06 6.99E-08 -2.93E-09 2.86E-11 S33 0 -8.11E-04 1.02E-05 -9.94E-08 -2.29E-10 -8.43E-11

[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 Telephoto end T1 1.7 37.4 T2 37.5 1.8 T3 6.4 10.5 T4 6.3 2.2

[0110] Table 7

[0111] Combination Figures 4 to 6 It can be seen that this embodiment can achieve a maximum aperture of F1.5, can correct the position chromatic aberration and magnification chromatic aberration between 380 and 940nm, and achieve 380-940nm confocal. In high and low temperature environments of -40℃ to 80℃, the zoom lens can still meet the full 4K resolution without refocusing. The zoom lens has a large aperture and a small size, and can be applied to more scenes with different conditions.

[0112] The third implementation method

[0113] See also Figures 7 to 9 In this embodiment, the present invention uses a total of 18 lenses, of which four lenses are aspherical lenses, and the seventh lens L7, the fifteenth lens L15 and the eighteenth lens L18 are all plastic aspherical lenses. Four cemented lens groups are used, such as Figure 7 As shown, it is a cemented lens group composed of a first lens L1 and a second lens L2, a fifth lens L5 and a sixth lens L6, a ninth lens L9 and a tenth lens L10, and an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13.

[0114] In this embodiment, F#: 1.4.

[0115] 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:

[0116]

[0117]

[0118] Table 8

[0119] 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.

[0120]

[0121]

[0122] Table 9

[0123] 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.

[0124] Wide angle Telephoto end T1 0.5 37.1 T2 36.7 0.1 T3 1.7 1.6 T4 9.6 9.7

[0125] Table 10

[0126] Combination Figures 7 to 9 It can be seen that this embodiment can achieve a maximum aperture of F1.4, can correct the position chromatic aberration and magnification chromatic aberration between 380 and 940nm, and achieve 380-940nm confocal. In high and low temperature environments of -40℃ to 80℃, the zoom lens can still meet the full 4K resolution without refocusing. The zoom lens has a large aperture and a small size, and can be applied to more scenes with different conditions.

[0127] 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 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) are arranged in sequence from the object side to the image side along the optical axis, a total of five lens groups, the zoom lens group (G2) and the focus lens group (G4) can both move along the optical axis, and the third fixed lens group (G5) has a negative focal power; 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, a total of three lenses; The zoom lens group (G2) comprises, in sequence, a fourth lens (L4) with negative optical power, a fifth lens (L5) with negative optical power, a sixth lens (L6) with positive optical power, and a seventh lens (L7), a total of four lenses; The second fixed lens group (G3) includes, in sequence, an eighth lens (L8) with positive optical power, a ninth lens (L9) with positive optical power, a tenth lens (L10) with negative optical power, an eleventh lens (L11) with negative optical power, a twelfth lens (L12) with positive optical power, and a thirteenth lens (L13) with negative optical power, a total of five lenses; The focus lens group (G4) includes, in sequence, a fourteenth lens (L14) with positive optical power, a fifteenth lens (L15) with negative optical power, and a sixteenth lens (L16) with positive optical power, a total of three lenses; The third fixed lens group (G5) includes in sequence a seventeenth lens (L17) with positive optical power and an eighteenth lens (L18) with negative optical power, a total of two lenses.

2. The zoom lens according to claim 1, wherein: The focal length FG1 of the first fixed lens group (G1) satisfies: 3≤FG1 / Fw≤5.5; The focal length FG2 of the zoom lens group (G2) satisfies: -1.8≤FG2 / Fw≤-0.6; The focal length FG3 of the second fixed lens group (G3) satisfies: 1≤FG3 / Fw≤2.8; The focal length FG4 of the focus lens group (G4) satisfies: 1.5≤FG4 / Fw≤4; The focal length FG5 of the third fixed lens group (G5) satisfies: FG5 / Fw≤-3; 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 first lens (L1) and the second lens (L2) are cemented together to form a cemented lens group.

4. The zoom lens according to claim 3, wherein: The first lens (L1) and the third lens (L3) are convex-concave; The second lens (L2) is of convex-convex type.

5. The zoom lens according to claim 1, wherein: Along the direction from the object side to the image side of the optical axis, it also includes: The seventh lens (L7) has a negative optical power, and the fifth lens (L5) and the sixth lens (L6) are cemented together to form a cemented lens group.

6. The zoom lens according to claim 5, wherein: Along the direction from the object side to the image side of the optical axis, The fourth lens (L4) is of convex-concave type; The fifth lens (L5) is of concave-concave type; The sixth lens (L6) is of convex-convex type; The paraxial region of the seventh lens (L7) is convex-concave.

7. The zoom lens according to claim 1, wherein: The eleventh lens (L11) and the twelfth lens (L12) or the eleventh lens (L11), the twelfth lens (L12) and the thirteenth lens (L13) are cemented together to form a cemented lens group.

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 eighth lens (L8), the ninth lens (L9) and the twelfth lens (L12) are convex-convex; The tenth lens (L10) and the thirteenth lens (L13) are concave-concave type; The eleventh lens (L11) is of convex-concave type.

9. The zoom lens according to claim 7 or 8, characterized in that: The refractive index Nd of the eighth lens (L8), the ninth lens (L9) and the tenth lens (L10) all satisfy the relationship: Nd≤1.

68.

10. The zoom lens according to claim 9, wherein: The Abbe number Vb8 of the eighth lens (L8) satisfies the relationship: 60≤Vb8≤96.

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 fourteenth lens (L14) is of convex-concave type; The fifteenth lens (L15) and the sixteenth lens (L16) are concave-convex types.

12. The zoom lens according to claim 1, wherein: Along the direction from the object side to the image side of the optical axis, The seventeenth lens (L17) is of concave-convex type; The paraxial region of the eighteenth lens (L18) is of a concave-concave type.

13. The zoom lens according to any one of claims 1 to 8 and 10 to 12, characterized in that: At least three of the lenses included in the zoom lens are aspherical lenses; at least two of the aspherical lenses are made of plastic.

14. The zoom lens according to claim 9, wherein: At least three of the lenses included in the zoom lens are aspherical lenses; at least two of the aspherical lenses are made of plastic.

15. The zoom lens according to any one of claims 1 to 8 and 10 to 12, characterized in that: The zoom lens comprises at least three cemented lens groups formed by cementing adjacent lenses.

16. The zoom lens according to claim 9, wherein: The zoom lens comprises at least three cemented lens groups formed by cementing adjacent lenses.

17. The zoom lens according to any one of claims 1 to 8, 10 to 12, 14 or 16, characterized in that: The target surface diameter φI covered by the zoom lens and the total length TTL of the zoom lens satisfy the relationship: 0.070≤φI / TTL≤0.

110.

18. The zoom lens according to claim 9, wherein: The target surface diameter φI covered by the zoom lens and the total length TTL of the zoom lens satisfy the relationship: 0.070≤φI / TTL≤0.

110.

19. The zoom lens according to claim 13, wherein: The target surface diameter φI covered by the zoom lens and the total length TTL of the zoom lens satisfy the relationship: 0.070≤φI / TTL≤0.

110.

20. The zoom lens according to claim 15, wherein: The target surface diameter φI covered by the zoom lens and the total length TTL of the zoom lens satisfy the relationship: 0.070≤φI / TTL≤0.

110.

21. The zoom lens according to any one of claims 1, 5 or 6, characterized in that: The absolute value D2 of the stroke of the zoom lens group (G2) and the total length TTL of the zoom lens satisfy the relationship: 0.3≤D2 / TTL≤0.

4.

22. The zoom lens according to any one of claims 1, 5, 6 or 11, characterized in that: The absolute value D4 of the stroke of the focus lens group (G4) and the absolute value D2 of the stroke of the zoom lens group (G2) satisfy the relationship: 0≤D4 / D2≤0.2.

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