A zoom lens

Abstract

The present invention relates to a zoom lens, comprising: a first lens group with positive focal power, a second lens group with negative focal power, an aperture, a third lens group with positive focal power and a fourth lens group with positive focal power, which are arranged in sequence from an object side to an image side; the first lens group and the third lens group are fixed groups, the second lens group is a zoom group movable along an optical axis, and the fourth lens group is a focus group movable along the optical axis; the second lens group and the third lens group satisfy: 9.5≤|(d1‑d2) / (f T / f W )|≤13, where d1 is the distance from the image side of the last lens of the second lens group to the object side of the first lens of the third lens group at the wide-angle end of the zoom lens; d2 is the distance from the image side of the last lens of the second lens group to the object side of the first lens of the third lens group at the telephoto end of the zoom lens; f T is the focal length at the telephoto end, f W is the focal length value at the wide-angle end. The present invention has high imaging quality.

Description

Technical Field

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

[0002] Zoom lenses are becoming increasingly popular in the security monitoring market because of their variable focal length, making them suitable for a variety of monitoring scenarios.

[0003] The existing constant aperture zoom lenses on the market still have some performance defects that limit their use scenarios. For example, the wide-angle angle is not large enough, the monitoring range is limited; the aperture is small and cannot meet the monitoring needs of low-light environments; the resolution is insufficient, the resolution is low, the zoom range is small, and the monitoring range is limited. Summary of the invention

[0004] The purpose of the present invention is to solve the above problem and provide a zoom lens to solve the problem of poor imaging performance of the zoom lens.

[0005] To achieve the above object, the present invention provides a zoom lens, comprising: a first lens group with positive focal power, a second lens group with negative focal power, an aperture stop, a third lens group with positive focal power, and a fourth lens group with positive focal power, which are arranged in sequence from the object side to the image side;

[0006] The first lens group and the third lens group are fixed groups, the second lens group is a zoom group movable along the optical axis, and the fourth lens group is a focus group movable along the optical axis;

[0007] The second lens group and the third lens group satisfy:

[0008] 9.5≤|(d1-d2) / (f T / f W )|≤13

[0009] Wherein, d1 represents the distance from the image side surface of the last lens of the second lens group to the object side surface of the first lens of the third lens group when the zoom lens is at the wide-angle end; d2 represents the distance from the image side surface of the last lens of the second lens group to the object side surface of the first lens of the third lens group when the zoom lens is at the telephoto end; f T is the focal length at the telephoto end, f W This is the focal length at the wide-angle end.

[0010] According to one aspect of the present invention, the first lens group includes: a lens with negative optical power and two lenses with positive optical power; wherein, from the object side to the image side, the optical power of the first lens and the third lens is positive, and the optical power of the second lens is negative;

[0011] According to one aspect of the present invention, the second lens group includes: three lenses with negative optical power and one lens with positive optical power; wherein, from the object side to the image side, the optical power of the fourth lens and the seventh lens is negative;

[0012] According to one aspect of the present invention, the third lens group includes: two lenses with negative optical power and six lenses with positive optical power; wherein, from the object side to the image side, the optical power of the ninth lens and the fifteenth lens is positive.

[0013] According to one aspect of the present invention, from the object side to the image side, the eighth lens element in the third lens group is an aspherical lens element with positive optical power.

[0014] According to one aspect of the present invention, the first lens group uses two lenses to form a first cemented lens group;

[0015] In the second lens group, the fifth lens and the sixth lens form a second cemented lens group;

[0016] In the third lens group, from the object side to the image side, the tenth lens, the eleventh lens and the twelfth lens constitute a third cemented lens group, and the thirteenth lens and the fourteenth lens constitute a fourth cemented lens group.

[0017] According to one aspect of the present invention, the fourth lens group includes: a lens with negative power and two lenses with positive power; wherein, from the object side to the image side, the sixteenth lens and the eighteenth lens have positive power, and the seventeenth lens has negative power; or,

[0018] The fourth lens group includes: two lenses with negative optical power and two lenses with positive optical power; wherein, from the object side to the image side, the optical power of the sixteenth lens and the eighteenth lens is positive, and the optical power of the seventeenth lens and the nineteenth lens is negative.

[0019] According to one aspect of the present invention, the focal length f1 of the first lens group and the focal length f3 of the third lens group satisfy the following relationship: 1.4≤|f1 / f3|≤3.5.

[0020] According to one aspect of the present invention, the focal length f at the wide-angle end of the zoom lens W The total optical length L of the zoom lens satisfies the following relationship: 0.1≤|f W / L|≤0.15.

[0021] According to one aspect of the present invention, in the first lens group, the refractive index Nd1 and the Abbe number Vd1 of at least one lens with positive optical power satisfy the following relationship: 1.4≤Nd1≤1.6, 60≤Vd1≤95.

[0022] According to one aspect of the present invention, in the second lens group, the refractive index Nd2 and the Abbe number Vd2 of at least two lenses with negative optical power satisfy the following relationship: 1.4≤Nd2≤1.6, 40≤Vd2≤70.

[0023] According to one aspect of the present invention, in the third lens group, at least two lenses with positive optical power have a refractive index Nd3 and an Abbe number Vd3 that satisfy the following relationship: 1.4≤Nd3≤1.6, 60≤Vd3≤95.

[0024] According to one solution of the present invention, the zoom lens of the present invention can achieve high-quality imaging at different magnifications by reasonably matching four lens groups.

[0025] According to one solution of the present invention, the zoom lens of the present invention achieves high-quality imaging effect by reasonably distributing glasses with different refractive indices.

[0026] According to one embodiment of the present invention, the zoom lens of the present invention has excellent resolution and image quality close to the diffraction limit.

[0027] According to one solution of the present invention, the zoom lens of the present invention has a large and constant aperture, ensuring uniform illumination at different magnifications.

[0028] According to one solution of the present invention, the zoom lens of the present invention can achieve infrared confocality, ensuring high-quality imaging at both visible light wavelengths and infrared light wavelengths.

[0029] According to one solution of the present invention, the zoom lens of the present invention has small distortion, high imaging quality, uniform image quality, fine image quality, rich colors and high contrast.

[0030] According to one solution of the present invention, the zoom lens of the present invention has high overall transmittance and uniform picture brightness.

[0031] According to one solution of the present invention, the zoom lens of the present invention can solve the problem of temperature drift and can produce clear images without refocusing in a temperature range of -40°C to 80°C.

[0032] According to one embodiment of the present invention, the zoom lens of the present invention has good individual component and assembly tolerances and good manufacturability.

[0033] According to one solution of the present invention, the first lens group serves as a fixed group and mainly plays the role of collecting light, which can make the light enter the imaging system smoothly, thereby reducing the tolerance sensitivity of the system. In addition, it can correct the system chromatic aberration and the temperature drift of the system, thereby ensuring good color reproduction and high-quality optical performance.

[0034] According to one solution of the present invention, the second lens group serves as a zoom group, which mainly has a zoom function to ensure the optical imaging quality of the system at different magnifications. Secondly, the temperature drift correction and chromatic aberration correction of the athermal system are ensured through the matching of lens optical powers, and the pressure of system tolerance sensitivity is shared.

[0035] According to one solution of the present invention, the third lens group is used as a fixed group, which is beneficial to reducing the tolerance sensitivity of the system, correcting the chromatic aberration of the system and correcting the temperature drift of the system by effectively matching the optical power of the lenses.

[0036] According to one solution of the present invention, the fourth lens group is used as a focusing group, and its main function is to reasonably focus during the zoom process to ensure high optical performance at different magnifications. In addition, the focal power of the lenses is matched to ensure that the light enters the image plane smoothly and maintain a small CRA. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram showing the structure of the zoom lens at the wide-angle end, the intermediate end and the telephoto end in the first embodiment;

[0038] Figure 2 Schematically shows the distortion, magnification chromatic aberration, and position chromatic aberration of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in the first embodiment;

[0039] Figure 3 is a diagram schematically showing the structure of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in Embodiment 2;

[0040] Figure 4 Schematically showing distortion, chromatic aberration of magnification, and position chromatic aberration of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in Embodiment 2;

[0041] Figure 5 is a diagram schematically showing the structure of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in Embodiment 3;

[0042] Figure 6 Schematically showing distortion, chromatic aberration of magnification, and position chromatic aberration of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in Embodiment 3;

[0043] Figure 7 is a diagram schematically showing the structure of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in Embodiment 4;

[0044] Figure 8 Schematically showing distortion, chromatic aberration of magnification, and position chromatic aberration of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in the fourth embodiment;

[0045] Fig. 9is a diagram schematically showing the structure of the zoom lens at the wide-angle end, the intermediate end, and the telephoto end in Embodiment 5;

[0046] Fig.10 Schematically shows the distortion, chromatic aberration of magnification, and position chromatic aberration of the zoom lens in the fifth embodiment at the wide-angle end, the intermediate end, and the telephoto end. DETAILED DESCRIPTION

[0047] 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.

[0048] 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 and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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.

[0049] 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.

[0050] like Figure 1 As shown, according to an embodiment of the present invention, a zoom lens of the present invention includes: a first lens group G1 with positive focal power, a second lens group G2 with negative focal power, an aperture, a third lens group G3 with positive focal power, and a fourth lens group G4 with positive focal power, which are arranged in sequence from the object side to the image side along the optical axis.

[0051] In this embodiment, the first lens group G1 and the third lens group G3 are fixed groups, the second lens group G2 is a zoom group that can move along the optical axis, and the fourth lens group G4 is a focus group that can move along the optical axis. In this embodiment, the interval between the second lens group G2 and the third lens group G3 gradually decreases from the wide-angle end to the telephoto end, and the second lens group G2 and the third lens group G3 satisfy:

[0052] 9.5≤|(d1-d2) / (f T / f W )|≤13

[0053] Wherein, d1 represents the distance from the image side of the last lens of the second lens group G2 to the object side of the first lens of the third lens group G3 at the wide-angle end of the zoom lens; d2 represents the distance from the image side of the last lens of the second lens group G2 to the object side of the first lens of the third lens group G3 at the telephoto end of the zoom lens; f T is the focal length at the telephoto end, f W This is the focal length at the wide-angle end.

[0054] Through the above arrangement, the second lens group G2 can move horizontally along the optical axis to achieve the zoom effect of the entire zoom lens. In addition, by setting the distance change between the second lens group G2 and the third lens group G3 and the focal length value of the zoom lens to the above relationship, it is beneficial to improve the imaging quality of the zoom lens at different magnifications.

[0055] like Figure 1 As shown, according to an embodiment of the present invention, the first lens group G1 includes: a lens with negative optical power and two lenses with positive optical power; wherein, from the object side to the image side, the optical power of the first lens L1 is positive, the optical power of the second lens L2 is negative, and the optical power of the third lens L3 is positive. In this embodiment, two lenses are used in the first lens group G1 to form the first cemented lens group B1 (such as the second lens L2 and the third lens L3).

[0056] Through the above arrangement, in the first lens group G1, by matching the positive and negative optical powers of the lenses, light can smoothly enter the zoom lens, which is beneficial to reducing the tolerance sensitivity of the entire zoom lens. In addition, through the above arrangement, the chromatic aberration of the zoom lens is also effectively corrected, which is beneficial to ensuring that the zoom lens has excellent color reproduction and high-quality optical performance.

[0057] like Figure 1 As shown, according to one embodiment of the present invention, the second lens group G2 includes: three lenses with negative optical power and one lens with positive optical power; wherein, from the object side to the image side, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 are arranged in sequence; the optical power of the fourth lens L4 and the seventh lens L7 is negative; the fifth lens L5 and the sixth lens L6 constitute a second cemented lens group B2.

[0058] Through the above arrangement, in the second lens group G2, by matching the positive and negative optical powers of the lenses, it is beneficial to correct the temperature drift and chromatic aberration of the athermal imaging system, ensuring that the imaging quality remains delicate, uniform and high in contrast under high and low temperature conditions. At the same time, through this arrangement of the second lens group G2, the pressure of the tolerance sensitivity of the zoom lens system is effectively shared and reduced.

[0059] like Figure 1As shown, according to an embodiment of the present invention, the third lens group G3 includes: two lenses with negative power and six lenses with positive power; wherein, from the object side to the image side, the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, the twelfth lens L12, the thirteenth lens L13, the fourteenth lens L14 and the fifteenth lens L15 are sequentially arranged. In this embodiment, the eighth lens L8 in the third lens group G3 is an aspherical lens with positive power, and the ninth lens L9 and the fifteenth lens L15 have positive power. In this embodiment, in the third lens group G3, from the object side to the image side, the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 constitute the third cemented lens group B3, and the thirteenth lens L13 and the fourteenth lens L14 constitute the fourth cemented lens group B4.

[0060] Through the above arrangement, in the third lens group G3, by reasonably matching the positive and negative optical powers between the lenses, the tolerance sensitivity of the system is effectively reduced and the imaging quality of the entire zoom lens system is improved, and the advantages of correcting the chromatic aberration and temperature drift of the zoom lens system are achieved.

[0061] like Figure 1 As shown, according to one embodiment of the present invention, the fourth lens group G4 includes: a lens with negative optical power and two lenses with positive optical power; wherein, from the object side to the image side, the sixteenth lens L16, the seventeenth lens L17 and the eighteenth lens L18 are arranged in sequence; the optical power of the sixteenth lens L16 and the eighteenth lens L18 is positive, and the optical power of the seventeenth lens L17 is negative.

[0062] Through the above arrangement, in the fourth lens group G4, by reasonably matching the positive and negative optical powers between the lenses, it is beneficial to ensure sufficient back focus and a larger imaging frame, and it is also beneficial to achieve a smaller main light incidence angle, thereby achieving a higher picture color reproduction of the zoom lens of the present invention.

[0063] According to another embodiment of the present invention, the fourth lens group G4 includes: two lenses with negative optical power and two lenses with positive optical power; wherein, from the object side to the image side, the sixteenth lens L16, the seventeenth lens L17, the eighteenth lens L18 and the nineteenth lens L19 are arranged in sequence; the optical power of the sixteenth lens L16 and the eighteenth lens L18 is positive, and the optical power of the seventeenth lens L17 and the nineteenth lens L19 is negative.

[0064] Through the above arrangement, in the fourth lens group G4, by reasonably matching the positive and negative optical powers between the lenses, it is beneficial to ensure sufficient back focus and a larger imaging frame, and it is also beneficial to achieve a smaller main light incidence angle, thereby achieving a higher picture color reproduction of the zoom lens of the present invention.

[0065] like Figure 1 As shown, according to an embodiment of the present invention, the focal length f1 of the first lens group G1 and the focal length f3 of the third lens group G3 satisfy the following relationship: 1.4≤|f1 / f3|≤3.5.

[0066] Through the above arrangement, the focal length of the first lens group G1 and the focal length of the third lens group G3 satisfy the above relationship, thereby achieving a reasonable match of the optical powers of the two lens groups, which is beneficial to correcting system chromatic aberration, reducing the tolerance sensitivity of the system, and improving imaging quality.

[0067] like Figure 1 As shown, according to one embodiment of the present invention, the focal length f at the wide-angle end of the zoom lens W The total optical length L of the zoom lens satisfies the following relationship: 0.1≤|f W / L|≤0.15.

[0068] Through the above setting, the relationship between the wide-angle focal length of the zoom lens and the total optical length of the zoom lens is set within the above range, which is beneficial to improving the imaging quality of the optical system, making the image quality delicate, uniform, and high in contrast. It is also beneficial to control the system volume and production costs.

[0069] like Figure 1 As shown, according to an embodiment of the present invention, in the first lens group G1, the refractive index Nd1 and the Abbe number Vd1 of at least one lens with positive optical power satisfy the following relationship: 1.4≤Nd1≤1.6, 60≤Vd1≤95.

[0070] The above arrangement is helpful to correct the chromatic aberration and high and low temperature performance of the zoom lens, and further improves the imaging quality of the entire zoom lens.

[0071] like Figure 1 As shown, according to one embodiment of the present invention, in the second lens group G2, the refractive index Nd2 and the Abbe number Vd2 of at least two lenses with negative optical power satisfy the following relationship: 1.4≤Nd2≤1.6, 40≤Vd2≤70.

[0072] The above arrangement is helpful to correct the chromatic aberration and high and low temperature performance of the zoom lens, and further improves the imaging quality of the entire zoom lens.

[0073] like Figure 1 As shown, according to one embodiment of the present invention, in the third lens group G3, the refractive index Nd3 and the Abbe number Vd3 of at least two lenses with positive optical power satisfy the following relationship: 1.4≤Nd3≤1.6, 60≤Vd3≤95.

[0074] The above arrangement is helpful to correct the chromatic aberration and high and low temperature performance of the zoom lens, and further improves the imaging quality of the entire zoom lens.

[0075] According to the present invention, the first lens group G1 serves as a fixed group and mainly plays the role of collecting light, which can make the light enter the imaging system smoothly, thereby reducing the tolerance sensitivity of the system. In addition, it can correct the system chromatic aberration and the temperature drift of the system, thereby ensuring good color reproduction and high-quality optical performance.

[0076] According to the present invention, the second lens group G2 serves as a zoom group, which mainly has a zoom function to ensure the optical imaging quality of the system at different magnifications. Secondly, it ensures the temperature drift correction and chromatic aberration correction of the athermal system through the combination of lens optical powers, and shares the pressure of system tolerance sensitivity.

[0077] According to the present invention, the third lens group G3 is used as a fixed group, which is beneficial to reducing the tolerance sensitivity of the system, correcting the chromatic aberration of the system and correcting the temperature drift of the system by effectively matching the optical power of the lenses.

[0078] According to the present invention, the fourth lens group G4 is used as a focusing group, and its main function is to reasonably focus during the zooming process to ensure high optical performance at different magnifications. In addition, the focal power of the lenses is matched to ensure that light enters the image plane smoothly and maintain a small CRA.

[0079] Five groups of specific implementations are given below according to the above configuration of the present invention to specifically illustrate the zoom lens according to the present invention.

[0080] The numerical values ​​of various embodiments that specifically meet the above conditional formula are summarized as shown in Table 1 below:

[0081]

[0082]

[0083] Table 1

[0084] In addition, in the following embodiments, the surface shapes of all aspheric lenses satisfy the aspheric equation:

[0085] Z=cy 2 / {1+[1-(1+k)c 2 y 2 ] 1 / 2}+A4y 4 +A6y 6 +A8y 8 +A 10 y 10 +A 12 y 12 +A 14 y 14 +A16 y 16

[0086] Among them, parameter c is the curvature corresponding to the radius of the aspheric lens, y is the radial coordinate of the aspheric lens, and its unit is the same as the lens length unit, k is the conic quadratic curve coefficient of the aspheric surface, and A4, A6...A16 are the corresponding order coefficients of the aspheric surface.

[0087] Implementation method 1:

[0088] The zoom lens according to the present invention has a total of 18 lenses, including a plurality of cemented lens groups, plus the stop surface Stop, a total of 32 surfaces. The 32 surfaces are arranged in sequence according to the structural order of the present invention. For the convenience of description, the 32 surfaces are numbered sur1 to sur32, wherein the stop surface is replaced by Stop instead of sur13, the cemented surfaces in the cemented lens group are represented by one number, and the imaging surface is represented by Image.

[0089] As mentioned above, in this embodiment, specific parameters of the zoom lens of the present invention are shown in Table 2.

[0090] Table 2 is a parameter table of implementation mode 1:

[0091]

[0092]

[0093]

[0094] Table 2 In this embodiment, the parameters of the zoom lens of this embodiment are shown in Table 3 below:

[0095] Wide angle middle Telephoto focal length 19.4 38.8 77.2 FNO. 1.2 1.2 1.2 Half field of view 19.8 9.6 4.7 Total length 160 160 160

[0096] Table 3 In this embodiment, the aspheric surface data is shown in Table 4 below:

[0097]

[0098] Table 4

[0099] See also Figure 1 , 2 As shown, by optimizing the above parameter values, the zoom lens of this embodiment achieves a constant large aperture performance with an FNO of up to 1.2, and ensures the optimal effect of the maximum field of view at the wide-angle end and the telephoto end, while satisfying the co-focus of visible light and infrared light. In addition, the zoom lens of the present invention also has the advantage of temperature compensation. Within a large temperature difference range, the lens does not need to be refocused to ensure the same resolution as at normal temperature.

[0100] Implementation method 2:

[0101] The zoom lens according to the present invention has a total of 18 lenses, including a plurality of cemented lens groups, plus the stop surface Stop, a total of 32 surfaces. The 32 surfaces are arranged in sequence according to the structural order of the present invention. For the convenience of description, the 32 surfaces are numbered sur1 to sur32, wherein the stop surface is replaced by Stop instead of sur13, the cemented surfaces in the cemented lens group are represented by one number, and the imaging surface is represented by Image.

[0102] As mentioned above, in this embodiment, specific parameters of the zoom lens of the present invention are shown in Table 5.

[0103] Table 5 is a parameter table of implementation mode 2:

[0104]

[0105]

[0106] Table 5 In this implementation mode, the parameters of the zoom lens of this implementation mode are shown in Table 6 below:

[0107] Wide-angle end middle Telephoto focal length 19.35 38.7 77.0 FNO. 1.2 1.2 1.2 Half field of view 19.5 9.6 4.7 Total length 162 162 162

[0108] Table 6 In this embodiment, the aspheric surface data is shown in Table 7 below:

[0109] serial number k A4 A6 A8 surf14 -0.285 -4.882E-06 -3.103E-08 1.304E-10 surf15 8.826 -9.348E-06 -3.936E-08 -1.281E-10 serial number A10 A12 A14 A16 surf14 -1.793E-12 7.143E-15 -1.786E-17 1.211E-20 surf15 6.870E-12 -9.722E-15 3.885E-17 -6.699E-20

[0110] Table 7

[0111] See also Figure 3 , 4 As shown, by optimizing the above parameter values, the zoom lens of this embodiment achieves a constant large aperture performance with an FNO of up to 1.2, and ensures the optimal effect of the maximum field of view at the wide-angle end and the telephoto end, while satisfying the co-focus of visible light and infrared light. In addition, the zoom lens of the present invention also has the advantage of temperature compensation. Within a large temperature difference range, the lens does not need to be refocused to ensure the same resolution as at normal temperature.

[0112] Implementation method three:

[0113] The zoom lens according to the present invention has a total of eighteen lenses, including a plurality of cemented lens groups, plus the stop surface Stop, a total of 31 surfaces. The 31 surfaces are arranged in sequence according to the structural order of the present invention. For the convenience of description, the 31 surfaces are numbered sur1 to sur31, wherein the stop surface is replaced by Stop instead of sur13, the cemented surfaces in the cemented lens group are represented by one number, and the imaging surface is represented by Image.

[0114] As mentioned above, in this embodiment, specific parameters of the zoom lens of the present invention are shown in Table 8 (in the table, standard represents a spherical surface, and aspheric represents an aspherical surface).

[0115] Table 8 is a parameter table of implementation mode 3:

[0116]

[0117]

[0118] Table 8 In this implementation mode, the parameters of the zoom lens of this implementation mode are shown in Table 9 below:

[0119] Wide-angle end middle Telephoto focal length 19 37.8 76.5 FNO. 1.2 1.2 1.2 Half field of view 20.4 10.1 4.9 Total length 158 158 158

[0120] Table 9

[0121] In this embodiment, the aspheric surface data is shown in Table 10 below:

[0122] serial number k A4 A6 A8 surf14 -0.217 -4.326E-06 -2.983E-08 1.363E-10 surf15 8.337 -8.015E-06 -3.768E-08 -1.253E-10 serial number A10 A12 A14 A16 surf14 -1.79E-12 7.134E-15 -1.785E-17 1.262E-20 surf15 7.009E-13 -9.844E-15 3.905E-17 -6.689E-20

[0123] Table 10

[0124] See also Figure 5 , 6 As shown, by optimizing the above parameter values, the zoom lens of this embodiment achieves a constant large aperture performance with an FNO of up to 1.2, and ensures the optimal effect of the maximum field of view at the wide-angle end and the telephoto end, while satisfying the co-focus of visible light and infrared light. In addition, the zoom lens of the present invention also has the advantage of temperature compensation. Within a large temperature difference range, the lens does not need to be refocused to ensure the same resolution as at normal temperature.

[0125] Implementation method 4:

[0126] The zoom lens according to the present invention has a total of 19 lenses, including a plurality of cemented lens groups, plus the stop surface Stop, a total of 33 surfaces. These 33 surfaces are arranged in sequence according to the structural order of the present invention. For the convenience of description, the 32 surfaces are numbered sur1 to sur33, wherein the stop surface is replaced by Stop instead of sur13, the cemented surfaces in the cemented lens group are represented by one number, and the imaging surface is represented by Image.

[0127] As mentioned above, in this embodiment, specific parameters of the zoom lens of the present invention are shown in Table 5.

[0128] Table 11 is a parameter table of implementation mode 4:

[0129]

[0130]

[0131]

[0132] Table 11 In this implementation mode, the parameters of the zoom lens of this implementation mode are shown in Table 12 below:

[0133] # Wide-angle end middle Telephoto focal length 19.4 40 75.2 FNO. 1.2 1.2 1.2 Half field of view 19.6 9.3 4.9 Total length 162 162 162

[0134] Table 12 In this embodiment, the aspheric surface data is shown in Table 13 below:

[0135]

[0136]

[0137] Table 13

[0138] See also Figure 7 , 8 As shown, by optimizing the above parameter values, the zoom lens of this embodiment achieves a constant large aperture performance with an FNO of up to 1.2, and ensures the optimal effect of the maximum field of view at the wide-angle end and the telephoto end, while satisfying the co-focus of visible light and infrared light. In addition, the zoom lens of the present invention also has the advantage of temperature compensation. Within a large temperature difference range, the lens does not need to be refocused to ensure the same resolution as at normal temperature.

[0139] Implementation method five:

[0140] The zoom lens according to the present invention has a total of 18 lenses, including a plurality of cemented lens groups, plus the stop surface Stop, a total of 33 surfaces. The 33 surfaces are arranged in sequence according to the structural order of the present invention. For the convenience of description, the 33 surfaces are numbered sur1 to sur31, wherein the stop surface is replaced by Stop instead of sur13, the cemented surfaces in the cemented lens group are represented by one number, and the imaging surface is represented by Image.

[0141] As mentioned above, in this embodiment, specific parameters of the zoom lens of the present invention are shown in Table 14.

[0142] Table 14 is a parameter table of implementation mode 5:

[0143]

[0144]

[0145]

[0146] Table 14

[0147] In this embodiment, the parameters of the zoom lens of this embodiment are shown in Table 15 below:

[0148] Wide angle middle Telephoto focal length 19.4 42.1 76.2 FNO. 1.2 1.2 1.2 Half field of view 18.2 8.6 4.5 Total length 163 163 163

[0149] Table 15

[0150] In this embodiment, the aspheric surface data is shown in Table 16 below:

[0151] serial number k A4 A6 A8 surf14 -0.18 -2.16E-06 -2.219E-08 7.792E-11 surf15 11.18 -2.685E-06 -4.942E-09 -3.582E-10 serial number A10 A12 A14 A16 surf14 -1.704E-12 9.317E-15 -2.919E-17 3.17E-20 surf15 2.006E-12 -9.198E-15 1.812E-17 -1.438E-20

[0152] Table 16

[0153] See also Fig. 9 , 10 As shown, by optimizing the above parameter values, the zoom lens of this embodiment achieves a constant large aperture performance with an FNO of up to 1.2, and ensures the optimal effect of the maximum field of view at the wide-angle end and the telephoto end, while satisfying the co-focus of visible light and infrared light. In addition, the zoom lens of the present invention also has the advantage of temperature compensation. Within a large temperature difference range, the lens does not need to be refocused to ensure the same resolution as at normal temperature.

[0154] From the above description, it can be seen that the zoom lens of the present invention achieves a maximum aperture of ≤1.2, and can achieve co-focusing of visible light and infrared light. In addition, the lens design takes temperature compensation into consideration. Within the temperature range of -40°C to 80°C, the lens does not need to be refocused to ensure the same resolution as at room temperature.

[0155] 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, characterized in that: include: The lens group includes a first lens group (G1) with positive power, a second lens group (G2) with negative power, an aperture, a third lens group (G3) with positive power, and a fourth lens group (G4) with positive power, which are arranged in sequence from the object side to the image side, totaling four lens groups; The first lens group (G1) and the third lens group (G3) are fixed groups, the second lens group (G2) is a zoom group that can move along the optical axis, and the fourth lens group (G4) is a focus group that can move along the optical axis; The second lens group (G2) comprises: three lenses with negative optical power and one lens with positive optical power, a total of four lenses; wherein, from the object side to the image side, the optical power of the fourth lens (L4), the fifth lens (L5) and the seventh lens (L7) is negative, and the optical power of the sixth lens (L6) is positive; The fourth lens group (G4) includes: one lens with negative power and two lenses with positive power, a total of three lenses; wherein, from the object side to the image side, the sixteenth lens (L16) and the eighteenth lens (L18) have positive power, and the seventeenth lens (L17) has negative power; or, The fourth lens group (G4) includes: two lenses with negative focal power and two lenses with positive focal power, a total of four lenses; wherein, from the object side to the image side, the focal power of the sixteenth lens (L16) and the eighteenth lens (L18) is positive, and the focal power of the seventeenth lens (L17) and the nineteenth lens (L19) is negative; The second lens group (G2) and the third lens group (G3) satisfy: 9.5≤|(d1-d2) / (f T / f W )|≤13 Wherein, d1 represents the distance from the image side surface of the last lens of the second lens group (G2) to the object side surface of the first lens of the third lens group (G3) at the wide-angle end of the zoom lens; d2 represents the distance from the image side surface of the last lens of the second lens group (G2) to the object side surface of the first lens of the third lens group (G3) at the telephoto end of the zoom lens; f T is the focal length at the telephoto end, f W This is the focal length at the wide-angle end.

2. The zoom lens according to claim 1, wherein: The first lens group (G1) comprises: one lens with negative optical power and two lenses with positive optical power, a total of three lenses; wherein, from the object side to the image side, the optical power of the first lens (L1) and the third lens (L3) is positive, and the optical power of the second lens (L2) is negative.

3. The zoom lens according to claim 1, wherein: The third lens group (G3) includes: two lenses with negative optical power and six lenses with positive optical power, totaling eight lenses; among which, from the object side to the image side, the optical power of the eighth lens (L8), the ninth lens (L9), the tenth lens (L10), the twelfth lens (L12), the fourteenth lens (L14) and the fifteenth lens (L15) is positive, and the optical power of the eleventh lens (L11) and the thirteenth lens (L13) is negative.

4. The zoom lens according to claim 3, wherein: From the object side to the image side, the eighth lens (L8) in the third lens group (G3) is an aspherical lens.

5. The zoom lens according to any one of claims 1 to 4, characterized in that: The first lens group (G1) uses two lenses to form a first cemented lens group (B1); In the second lens group (G2), the fifth lens (L5) and the sixth lens (L6) form a second cemented lens group (B2); In the third lens group (G3), from the object side to the image side, the tenth lens (L10), the eleventh lens (L11) and the twelfth lens (L12) constitute a third cemented lens group (B3), and the thirteenth lens (L13) and the fourteenth lens (L14) constitute a fourth cemented lens group (B4).

6. The zoom lens according to any one of claims 1 to 4, characterized in that: The focal length f1 of the first lens group (G1) and the focal length f3 of the third lens group (G3) satisfy the following relationship: 1.4≤|f1 / f3|≤3.

5.

7. The zoom lens according to any one of claims 1 to 4, characterized in that: The wide-angle focal length of the zoom lens is f W The total optical length L of the zoom lens satisfies the following relationship: 0.1≤|f W / L|≤0.

15.

8. The zoom lens according to any one of claims 1 to 4, characterized in that: In the first lens group (G1), the refractive index Nd1 and the Abbe number Vd1 of at least one lens with positive optical power satisfy the following relationship: 1.4≤Nd1≤1.6, 60≤Vd1≤95.

9. The zoom lens according to any one of claims 1 to 4, characterized in that: In the second lens group (G2), the refractive index Nd2 and the Abbe number Vd2 of at least two lenses with negative optical power satisfy the following relationship: 1.4≤Nd2≤1.6, 40≤Vd2≤70.

10. The zoom lens according to any one of claims 1 to 4, characterized in that: In the third lens group (G3), at least two lenses with positive optical power have a refractive index Nd3 and an Abbe number Vd3 that satisfy the following relationship: 1.4≤Nd3≤1.6, 60≤Vd3≤95.

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