Zoom lens

Abstract

The embodiment of the utility model discloses a zoom lens, which comprises a first fixed lens group, a first zoom lens group, a diaphragm, a second zoom lens group, a focusing lens group and a second fixed lens group which are sequentially arranged from an object space to an image space along an optical axis, and the focal powers are positive, negative, positive and negative in sequence; wherein the first fixed lens group comprises three lenses, and the focal powers of the three lenses are negative, positive and positive in sequence; the first zoom lens group comprises three lenses with negative focal power, negative focal power and positive focal power in sequence; the second zoom lens group comprises four lenses, and the focal powers of the four lenses are negative, positive, positive and negative in sequence; the focusing lens group comprises three lenses, and the focal powers of the three lenses are positive, positive and negative in sequence; the second fixed lens group comprises a lens, and the focal power is positive. According to the embodiment of the utility model, the 14 lenses and the plate glass with a certain thickness are used, and the use requirements of small distortion, large aperture and clear imaging at the wave band of 436nm-656nm can be met under the condition of adapting to a 1 / 1.2 ''target surface.

Description

Technical Field

[0001] The embodiment of the utility model relates to the technical field of optical lenses, and in particular to a zoom lens. Background Art

[0002] With the rise of the live broadcast industry, the requirements for live broadcast lenses are gradually becoming higher, and zoom lenses are gradually being used in the live broadcast industry. Traditional zoom lenses are more difficult to focus at close distances and in fast-changing environments, as required by the live broadcast industry.

[0003] Currently, the mainstream chip size of the live broadcast lenses used most in the market is 1 / 2.7" or 1 / 1.8", and the image quality is poor at close distances, the speed of adapting to ambient brightness is slow, and the illumination is low. Therefore, it is necessary to develop a 4K live broadcast lens with a small size, large aperture, small distortion, and high and low temperature confocality. Utility Model Content

[0004] The utility model provides a zoom lens adapted to a 1 / 1.2″ target surface, meeting the use requirements of small distortion, large aperture and clear imaging in a 436nm-656nm band.

[0005] The embodiment of the utility model provides a zoom lens, comprising a first fixed lens group with positive optical power, a first variable magnification lens group with negative optical power, an aperture, a second variable magnification lens group with positive optical power, a focusing lens group with positive optical power, and a second fixed lens group with negative optical power, which are arranged in sequence from the object side to the image side along the optical axis;

[0006] The first fixed lens group includes a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power;

[0007] The first variable power lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power;

[0008] The second variable power lens group includes a seventh lens with negative optical power, an eighth lens with positive optical power, a ninth lens with positive optical power, and a tenth lens with negative optical power;

[0009] The focusing lens group includes an eleventh lens with positive optical power, a twelfth lens with positive optical power, and a thirteenth lens with negative optical power;

[0010] The second fixed lens group includes a fourteenth lens having positive optical power;

[0011] The first variable-power lens group, the second variable-power lens group, the focusing lens group and the second fixed lens group each include at least one aspherical lens;

[0012] During the magnification change process, the positions of the first fixed lens group and the second fixed lens group are fixed, the first magnification change lens group and the second magnification change lens group move along the optical axis to change the magnification, and the focusing lens group moves along the optical axis to focus.

[0013] Optionally, the fifth lens is an aspherical lens;

[0014] The seventh lens is an aspherical lens;

[0015] The eleventh lens is an aspherical lens;

[0016] The fourteenth lens is an aspherical lens.

[0017] Optionally, the focal length F1 of the first fixed lens group, the focal length F2 of the first variable magnification lens group, the focal length F3 of the second variable magnification lens group, the focal length F4 of the focusing lens group, the focal length F5 of the second fixed lens group and the wide-angle end focal length FW of the zoom lens meet the following conditions:

[0018] 44.14≤F1 / FW≤45.51;

[0019] -25.22≤F2 / FW≤-24.86;

[0020] 31.70≤F3 / FW≤35.89;

[0021] 9.94≤F4 / FW≤11.49;

[0022] 56.32≤F5 / FW≤71.72.

[0023] Optionally, the first lens is of convex-concave type, the second lens is of convex-convex type, and the third lens is of convex-concave type;

[0024] The fourth lens is a convex-concave type, the fifth lens is a concave-concave type, and the sixth lens is a convex-convex type;

[0025] The seventh lens is of concave-concave type, the eighth lens is of convex-convex type, the ninth lens is of convex-convex type, and the tenth lens is of concave-concave type;

[0026] The eleventh lens is of convex-convex type, the twelfth lens is of convex-convex type, and the thirteenth lens is of concave-concave type;

[0027] In the second fixed lens group, the fourteenth lens is of convex-concave type.

[0028] Optionally, the first fixed lens group includes at least one cemented lens group, and / or the second variable power lens group includes at least one cemented lens group, and / or the focusing lens group includes at least one cemented lens group.

[0029] Optionally, materials of the fifth lens, the seventh lens, the eleventh lens and the fourteenth lens meet the following conditions:

[0030] 1.49≤nd5≤1.59;67.0≤vd5≤81.6;

[0031] 1.44≤nd7≤1.59;68.6≤vd7≤95.1;

[0032] 1.49≤nd11≤1.51;64.8≤vd11≤81.6;

[0033] 1.78≤nd14≤1.89;26.9≤vd14≤50.3;

[0034] Among them, nd5, nd7, nd11, and nd14 respectively represent the refractive indices of the fifth lens, the seventh lens, the eleventh lens, and the fourteenth lens, and vd5, vd7, vd11, and vd14 respectively represent the Abbe numbers of the fifth lens, the seventh lens, the eleventh lens, and the fourteenth lens.

[0035] Optionally, the second variable power lens group and the focusing lens group satisfy the following condition: 1.156≤S3 / S4≤1.493;

[0036] Among them, S2 is the maximum distance that the first zoom lens group can move, and S4 is the maximum distance that the focus lens group can move.

[0037] Optionally, the focal lengths of the wide-angle end and the telephoto end of the zoom lens need to meet the following conditions: 2.69≤FT / FW≤2.97;

[0038] Wherein, FW represents the focal length of the zoom lens at the wide-angle end, and FT represents the focal length of the zoom lens at the telephoto end.

[0039] Optionally, the zoom lens satisfies the following condition: 5.24≤TTL / S2≤5.68;

[0040] Wherein, TTL represents the total optical length of the zoom lens, and S2 represents the maximum distance that the first zoom lens group can move.

[0041] Optionally, the zoom lens meets the following conditions: 1.15 <FNO<1.25;

[0042] Wherein, FNO is the aperture number of the zoom lens at the full focal length.

[0043] The zoom lens provided by the embodiment of the utility model is provided with a first fixed lens group, a first variable magnification lens group, an aperture, a second variable magnification lens group, a focusing lens group, and a second fixed lens group, and the optical focal powers are positive, negative, positive, positive, and negative in sequence; wherein the first fixed lens group includes three lenses, and the optical focal powers are negative, positive, and positive in sequence; the first variable magnification lens group includes three lenses, and the optical focal powers are negative, negative, and positive in sequence; the second variable magnification lens group includes four lenses, and the optical focal powers are negative, positive, positive, and negative in sequence; the focusing lens group includes three lenses, and the optical focal powers are positive, positive, and negative in sequence; the second fixed lens group includes one lens, and the optical focal power is positive, positive, and negative in sequence, so that the first variable magnification lens group and the second variable magnification lens group move along the optical axis to zoom, while the focusing lens group moves along the optical axis to compensate for aberrations, thereby achieving clear imaging. The embodiment of the utility model uses 14 lenses and a certain thickness of flat glass, which can be adapted to a 1 / 1.2″ target surface and meet the use requirements of small distortion, large aperture, and clear imaging in the 436nm-656nm band. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic diagram of the structure of the zoom lens at the wide-angle end provided in the first embodiment of the utility model;

[0045] Figure 2 A schematic diagram of the structure of the zoom lens at the telephoto end provided by the first embodiment of the utility model;

[0046] Figure 3 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the utility model at the infinite object distance at the wide-angle end;

[0047] Figure 4 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the utility model at the wide-angle end with an object distance of 1m;

[0048] Figure 5 A light fan diagram of the zoom lens provided in the first embodiment of the utility model at the infinite object distance at the wide-angle end;

[0049] Figure 6 This is a light fan diagram of the zoom lens provided in the first embodiment of the utility model at the wide-angle end at an object distance of 1m;

[0050] Figure 7 This is a field curvature distortion diagram of the zoom lens provided in the first embodiment of the utility model at infinity at the wide-angle end;

[0051] Figure 8 This is a field curvature distortion diagram of the zoom lens provided in Example 1 of the utility model at the wide-angle end at an object distance of 1m;

[0052] Fig. 9The axial aberration curve of the zoom lens provided in the first embodiment of the utility model at infinity at the wide-angle end;

[0053] Fig.10 The axial aberration curve of the zoom lens provided in the first embodiment of the utility model at the object distance of 1m at the wide-angle end;

[0054] Fig.11 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end;

[0055] Fig.12 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the utility model at the telephoto end with an object distance of 1m;

[0056] Fig.13 A light fan diagram of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end;

[0057] Fig.14 This is a light fan diagram of the zoom lens provided in the first embodiment of the utility model at the telephoto end at an object distance of 1m;

[0058] Fig.15 A field curvature distortion diagram of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end;

[0059] Fig.16 This is a field curvature distortion diagram of the zoom lens provided in Embodiment 1 of the utility model at a telephoto end at an object distance of 1m;

[0060] Fig.17 The axial aberration curve of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end;

[0061] Fig.18 The axial aberration curve of the zoom lens provided in the first embodiment of the utility model at the telephoto end at an object distance of 1m;

[0062] Fig.19 A schematic diagram of the structure of the zoom lens provided in Embodiment 2 of the present utility model at infinity at the wide-angle end;

[0063] Fig. 20 A schematic diagram of the structure of the zoom lens provided in the second embodiment of the utility model at the telephoto end with an object distance of 1m;

[0064] Fig.21 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end;

[0065] Fig. 22 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the utility model at the wide-angle end with an object distance of 1m;

[0066] Fig.23 A light fan diagram of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end;

[0067] Fig.24 This is a light fan diagram of the zoom lens provided in the second embodiment of the utility model at the wide-angle end at an object distance of 1m;

[0068] Fig.25 This is a field curvature distortion diagram of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end;

[0069] Fig.26 This is a field curvature distortion diagram of the zoom lens provided in Example 2 of the utility model at the wide-angle end at an object distance of 1m;

[0070] Fig. 27 The axial aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end;

[0071] Fig.28 The axial aberration curve of the zoom lens provided in the second embodiment of the utility model at the wide-angle end at an object distance of 1m;

[0072] Fig.29 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end;

[0073] Fig.30 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the utility model at the telephoto end with an object distance of 1m;

[0074] Fig.31 A light fan diagram of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end;

[0075] Fig.32 This is a light fan diagram of the zoom lens provided in the second embodiment of the utility model at the telephoto end at an object distance of 1m;

[0076] Fig.33 This is a field curvature distortion diagram of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end;

[0077] Fig.34 This is a field curvature distortion diagram of the zoom lens provided in the second embodiment of the utility model at the telephoto end at an object distance of 1m;

[0078] Fig.35 The axial aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end;

[0079] Fig.36 The axial aberration curve of the zoom lens provided in the second embodiment of the utility model at the telephoto end at an object distance of 1m;

[0080] Fig.37 A schematic diagram of the structure of the zoom lens provided in Embodiment 3 of the present utility model at infinity at the wide-angle end;

[0081] Fig.38 This is a schematic diagram of the structure of the zoom lens provided in Embodiment 3 of the present utility model at the telephoto end at an object distance of 1m;

[0082] Fig.39 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end;

[0083] Fig.40 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the utility model at the wide-angle end with an object distance of 1m;

[0084] Fig.41 This is a light fan diagram of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end;

[0085] Fig.42 This is a light fan diagram of the zoom lens provided in the third embodiment of the utility model at the wide-angle end at an object distance of 1m;

[0086] Fig.43 This is a field curvature distortion diagram of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end;

[0087] Fig.44 This is a field curvature distortion diagram of the zoom lens provided in Embodiment 3 of the present utility model at the wide-angle end at an object distance of 1m;

[0088] Fig.45 The axial aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end;

[0089] Fig.46 The axial aberration curve of the zoom lens provided in the third embodiment of the utility model at the wide-angle end at an object distance of 1m;

[0090] Fig.47 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the telephoto end;

[0091] Fig.48 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the utility model at the telephoto end with an object distance of 1m;

[0092] Fig.49 This is a light fan diagram of the zoom lens provided in the third embodiment of the utility model at the infinite telephoto end;

[0093] Fig.50 This is a light fan diagram of the zoom lens provided in the third embodiment of the utility model at the telephoto end at an object distance of 1m;

[0094] Fig.51 This is a field curvature distortion diagram of the zoom lens provided in Example 3 of the utility model at infinity at the telephoto end.

[0095] Fig.52 This is a field curvature distortion diagram of the zoom lens provided in Example 3 of the utility model at the telephoto end at an object distance of 1m.

[0096] Fig.53 The axial aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the telephoto end;

[0097] Fig.54 This is the axial aberration curve of the zoom lens provided in Example 3 of the utility model at the telephoto end at an object distance of 1m. DETAILED DESCRIPTION

[0098] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0099] Figure 1 1 is a schematic diagram of the structure of a zoom lens at the wide-angle end provided by the first embodiment of the utility model. Figure 2 yes Figure 1 The structure diagram of the zoom lens at the telephoto end is shown in FIG. Figure 1 and Figure 2 The zoom lens comprises a first fixed lens group G1 with positive focal power, a first variable magnification lens group G2 with negative focal power, an aperture STO, a second variable magnification lens group G3 with positive focal power, a focusing lens group G4 with positive focal power, and a second 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;

[0100] The first fixed lens group G1 includes 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;

[0101] The first variable power lens group G2 includes a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, and a sixth lens L6 with positive optical power;

[0102] The second zoom lens group G3 includes a seventh lens L7 with negative power, an eighth lens L8 with positive power, a ninth lens L9 with positive power, and a tenth lens L10 with negative power;

[0103] The focusing lens group G4 includes an eleventh lens L11 having positive refractive power, a twelfth lens L12 having positive refractive power, and a thirteenth lens L13 having negative refractive power;

[0104] The second fixed lens group G5 includes a fourteenth lens L14 having positive optical power;

[0105] The first variable-power lens group, the second variable-power lens group, the focus lens group, and the second fixed lens group G5 each include at least one aspherical lens;

[0106] During the zooming process, the positions of the first fixed lens group G1 and the second fixed lens group G5 are fixed, the first zoom lens group G2 and the second zoom lens group G3 move along the optical axis to zoom, and the focusing lens group G4 moves along the optical axis to focus.

[0107] First of all, it can be understood that the focal power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power, the stronger the ability to bend light, and the smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is a positive number, the refraction of light is convergent; when the focal power is a negative number, the refraction of light is divergent. The focal power can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens or lens group, and can also be used to characterize a system composed of multiple lenses (i.e., a group or lens group). In this embodiment, the first fixed lens group G1, the first variable magnification lens group G2, the second variable magnification lens group G3, the focus lens group G4, and the second fixed lens group G5 can be arranged in a lens barrel, the first fixed lens group G1 and the second fixed lens group G5 are fixed in the lens barrel, and the first variable magnification lens group G2, the second variable magnification lens group G3 and the focus lens group G4 can move back and forth along the optical axis in the lens barrel. Among them, the first variable magnification lens group G2 and the second variable magnification lens group G3 are used to adjust the focal length of the lens by moving to achieve the focal length change of the zoom lens, and the focus lens group G4 is used to compensate for the aberration caused by the movement of the first variable magnification lens group G2 and the second variable magnification lens group G3. It can be understood that in the process of zooming by moving the corresponding groups of the zoom lens, when the focal length is the shortest, the zoom lens is at the wide-angle end, and when the focal length is the longest, the zoom lens is at the telephoto end. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical powers, and also has different lengths or shapes.

[0108] In this embodiment, by setting the focal length of the first fixed lens group G1 to be positive and the focal length of the first variable magnification lens group G2 to be negative, it is ensured that light can enter the subsequent structure through the first fixed lens group G1. At the same time, the focal lengths of the first fixed lens group G1, the first variable magnification lens group G2, the second variable magnification lens group G3, the focusing lens group G4 and the second fixed lens group G5 are positive, negative, positive, positive and negative, respectively. By using this combination of focal lengths, it can be ensured that light does not produce a sudden change and passes through the lens smoothly, while achieving a longer focal length. In addition, the aperture STO is set between the first variable magnification lens group G2 and the second variable magnification lens group G3, with the purpose of enabling the high-order aberrations of the lens to be controlled in the front half of the lens, ensuring that the image height can be increased and the target surface can be expanded in the back half of the lens, while achieving good image quality to meet the use requirements in more situations.

[0109] In addition, the first fixed lens group G1 includes three lenses whose optical powers are negative, positive and positive in sequence, the first variable magnification lens group G2 includes three lenses whose optical powers are negative, negative and positive in sequence, the second variable magnification lens group G3 includes four lenses whose optical powers are negative, positive, positive and negative in sequence, the focusing lens group G4 includes three lenses whose optical powers are positive, positive and negative in sequence, and the second fixed lens group G5 includes a lens whose optical power is positive. In addition, the first variable magnification lens group G2, the second variable magnification lens group G3, the focusing lens group G4 and the second fixed lens group G5 each include at least one aspherical lens, so that the lenses can be connected with each other through a Mylar sheet or a spacer. Through the coordination of the lenses with different optical focal lengths as mentioned above, on the one hand, the role of each lens in its group can be limited, ensuring the coordination of the lenses in each group to achieve the role of the group; on the other hand, on the basis of ensuring the limited optical focal length of the lens, the aberration correction effect of the aspheric lens can be used to adjust the zoom function or compensation function of the group, so that each group after the first fixed lens group G1 can propagate backward the image that has been corrected to a certain extent, thereby helping to improve the imaging quality of the zoom lens, so that the zoom lens can produce clear images within different focal length ranges, especially at close focal lengths, and meet the current camera requirements in live broadcast scenarios.

[0110] It should be added that the zoom lens of the present invention is also provided with a flat glass CG; the flat glass CG is located on one side of the image side surface of the fourteenth lens L14, and the flat glass CG can protect the photosensitive chip (not shown in the figure) in the imaging sensor located on the image plane. The photosensitive chip is used to convert the light signal collected by the zoom lens into an electrical signal, thereby realizing the imaging of the zoom lens.

[0111] The zoom lens provided by the embodiment of the utility model is provided with a first fixed lens group G1, a first variable magnification lens group G2, an aperture STO, a second variable magnification lens group G3, a focusing lens group G4, and a second fixed lens group G5, and the optical focal powers are positive, negative, positive, positive, and negative in sequence; wherein the first fixed lens group G1 includes three lenses, and the optical focal powers are negative, positive, and positive in sequence; the first variable magnification lens group G2 includes three lenses, and the optical focal powers are negative, negative, and positive in sequence; the second variable magnification lens group G3 includes four lenses, and the optical focal powers are negative, positive, positive, and negative in sequence; the focusing lens group G4 includes three lenses, and the optical focal powers are positive, positive, and negative in sequence; the second fixed lens group G5 includes one lens, and the optical focal power is positive, positive, and negative in sequence, so that the first variable magnification lens group G2 and the second variable magnification lens group G3 move along the optical axis to zoom, while the focusing lens group G4 moves along the optical axis to compensate for aberrations, thereby achieving clear imaging. The embodiment of the utility model uses 14 lenses and a certain thickness of flat glass, which can be adapted to a 1 / 1.2″ target surface and meet the use requirements of small distortion, large aperture, and clear imaging in the 436nm-656nm band.

[0112] In a specific embodiment, optionally, the fifth lens L5 is an aspherical lens; the seventh lens L7 is an aspherical lens; the eleventh lens L11 is an aspherical lens; and the fourteenth lens L14 is an aspherical lens.

[0113] As mentioned above, in this embodiment, an aspheric lens is provided in each of the first zoom lens group, the second zoom lens group, the focusing lens group and the second fixed lens group G5, wherein the lens closest to the object plane in the second zoom lens group, namely the seventh lens L7, is provided as an aspheric lens, and the lens closest to the object plane in the focusing lens group, namely the eleventh lens L11, is provided as an aspheric lens, so as to correct the image quality entering the current group, thereby ensuring the imaging clarity of the entire zoom lens.

[0114] In a specific embodiment, optionally, the focal length F1 of the first fixed lens group G1, the focal length F2 of the first variator lens group G2, the focal length F3 of the second variator lens group G3, the focal length F4 of the focus lens group G4, the focal length F5 of the second fixed lens group G5, and the wide-angle end focal length FW of the zoom lens satisfy the following conditions:

[0115] 44.14≤F1 / FW≤45.51;

[0116] -25.22≤F2 / FW≤-24.86;

[0117] 31.70≤F3 / FW≤35.89;

[0118] 9.94≤F4 / FW≤11.49;

[0119] 56.32≤F5 / FW≤71.72.

[0120] In this specific embodiment, optionally, by setting the optical focal length of the five groups and the focal length of the wide-angle end of the zoom lens to meet the above conditions, a more refined and reasonable combination of optical focal lengths is achieved on the basis of satisfying the positive-negative-positive-positive-negative optical focal length combination, so that light can pass through the lens more smoothly, and at the same time can correct the high-order aberrations of the lens to a great extent, thereby improving the imaging quality.

[0121] In a specific embodiment, the first lens L1 is a convex-concave type, the second lens L2 is a convex-convex type, and the third lens L3 is a convex-concave type;

[0122] The fourth lens L4 is a convex-concave type, the fifth lens L5 is a concave-concave type, and the sixth lens L6 is a convex-convex type;

[0123] The seventh lens L7 is a concave-concave type, the eighth lens L8 is a convex-convex type, the ninth lens L9 is a convex-convex type, and the tenth lens L10 is a concave-concave type;

[0124] The eleventh lens L11 is of convex-convex type, the twelfth lens L12 is of convex-convex type, and the thirteenth lens L13 is of concave-concave type;

[0125] In the second fixed lens group, the fourteenth lens L14 is of convex-concave type.

[0126] In a specific embodiment, optionally, the first fixed lens group includes at least one cemented lens group, and / or the second variable magnification lens group includes at least one cemented lens group, and / or the focusing lens group includes at least one cemented lens group. Figure 1 and Figure 2 In the first fixed lens group, the first lens L1 and the second lens L2 can be set to form a doublet lens group; in the second variable power lens group, the ninth lens L9 and the tenth lens L10 can be set to form a doublet lens; in the focusing lens group, the twelfth lens L12 and the thirteenth lens L13 can be set to form a doublet lens.

[0127] Among them, gluing adjacent partial lenses to form a glued lens group can reduce the distance between lenses, can properly correct chromatic aberration, and can improve field curvature and coma, thereby further optimizing the image quality. For the above-mentioned glued lens group in the second zoom lens group, it can well correct chromatic aberration when the light just passes through the aperture, and avoid the situation where chromatic aberration is superimposed at the rear end of the lens, resulting in the need for a large amount of high Abbe number material to pull back at the rear end, saving costs while improving image quality. For the above-mentioned glued lens group in the focus lens group, during the zooming process, the focus lens group is responsible for focusing the optical system with a changed focal length. The use of aspherical lenses and glued lens groups can correct chromatic aberration and high-order aberrations generated in the focus lens group, greatly reducing the aberration pressure of other lens groups at different focal lengths, thereby achieving the use requirement of clear focus of the optical system at all focal lengths.

[0128] In a specific embodiment, optionally, materials of the fifth lens L5, the seventh lens L7, the eleventh lens L11, and the fourteenth lens L14 meet the following conditions:

[0129] 1.49≤nd5≤1.59;67.0≤vd5≤81.6;

[0130] 1.44≤nd7≤1.59;68.6≤vd7≤95.1;

[0131] 1.49≤nd11≤1.51;64.8≤vd11≤81.6;

[0132] 1.78≤nd14≤1.89;26.9≤vd14≤50.3;

[0133] Among them, nd5, nd7, nd11, and nd14 respectively represent the refractive indices of the fifth lens L5, the seventh lens L7, the eleventh lens L11, and the fourteenth lens L14, and vd5, vd7, vd11, and vd14 respectively represent the Abbe numbers of the fifth lens L5, the seventh lens L7, the eleventh lens L11, and the fourteenth lens L14.

[0134] In this embodiment, in order to ensure that the optical system can stably image the aberrations at the full focal length, a method usually used is to individually eliminate chromatic aberrations and control aberrations in each lens group. Aspherical lenses have a good ability to control high-order aberrations of the optical system. By adding aspherical lenses to the first zoom lens group G2, the second zoom lens group and the focusing lens group that need to move during the zooming process, and reasonably matching the refractive indices of the fifth lens L5, the seventh lens L7 and the eleventh lens L11, the aberrations of each group can be controlled to a great extent. In combination with the refractive index and Abbe number of the fourteenth lens L14, it is possible to ensure that the light at the front end is smoothly emitted, the resolution and image height are guaranteed, and the illumination is guaranteed while improving the imaging quality of the lens.

[0135] In addition, in the embodiments of the present utility model, each lens is a glass lens. Among them, the properties of the glass lens are insensitive to temperature. The lens using all glass lenses has more consistent performance under different temperature conditions, has the characteristics of stable high and low temperature performance, and improves the environmental adaptability of the zoom lens; the introduction of glass aspherical lenses also corrects the chromatic aberration and higher-order aberrations of the lens to a great extent, and there is a wider range of options compared to plastic aspherical lenses. More diverse structures can be used in the structural selection, improving the market competitiveness of the lens.

[0136] In a specific embodiment, optionally, the focal lengths of the wide-angle end and the telephoto end of the zoom lens need to meet the following conditions: 2.69 ≤ FT / FW ≤ 2.97; where FW represents the focal length of the wide-angle end of the zoom lens, and FT represents the focal length of the telephoto end of the zoom lens.

[0137] In this embodiment, by controlling the focal length ratio of the wide-angle end and the telephoto end of the lens, under the conditions of ensuring the zoom range and the large target surface, the distortion can be controlled within a reasonable small range, meeting the requirement of small distortion of the lens.

[0138] In a specific embodiment, optionally, the zoom lens meets the following conditions: 5.24 ≤ TTL / S2 ≤ 5.68; where TTL represents the overall optical length of the zoom lens, and S2 represents the maximum movable distance of the first zoom lens group.

[0139] In this embodiment, the limitation of the first zoom lens group and the overall optical length of the lens can compress the lens space, ensuring the required imaging quality and zoom degree under the condition of a small lens volume.

[0140] In a specific embodiment, optionally, the zoom lens meets the following conditions: 1.15 < FNO < 1.25; where FNO is the aperture number of the entire focal length of the zoom lens.

[0141] Therefore, by setting a diaphragm STO between the first zoom lens group G2 and the second zoom lens group G3, the above aperture requirements can be achieved, enabling the zoom lens to have a relatively large aperture throughout the entire focal length and ensuring the imaging brightness.

[0142] In summary, the embodiments of the present utility model use 14 lenses and a flat glass of a certain thickness to achieve a five-element all-glass zoom lens with small distortion, large aperture, clear imaging, high and low temperature confocal, etc. under a 1 / 1.2″ target surface in the 436nm - 656nm band, which can solve the problems of poor image quality when the distance is relatively close, slow adaptation speed to environmental brightness, low illuminance, etc. of existing zoom lenses, and meet the requirements of live broadcast scenarios.

[0143] Based on the same concept above, the utility model provides three different specific embodiments, and the relationship between the optical power and the design range of related physical optical parameters are shown in Table 1:

[0144] Table 1 Relationship between the focal powers of the lenses and the design values ​​of the relevant physical optical parameters in the three embodiments

[0145]

[0146]

[0147] like Figure 1 and Figure 2 The parameter design values ​​of each lens in the zoom lens of the first embodiment are shown in Table 2:

[0148] Table 2 Design values ​​of each lens in the zoom lens in Example 1

[0149]

[0150]

[0151] The surface numbers in Table 2 are numbered according to the order of the surfaces of each lens; among them, "STO" represents the aperture of the zoom lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "INF" indicates that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light. The zoom interval values ​​in Table 2 above are shown in Table 3:

[0152] Table 3 A design value of the zoom interval of the zoom lens at the wide-angle end and the telephoto end in Example 1

[0153]

[0154]

[0155] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0156]

[0157] Wherein, Z is the axial distance from the curved surface at a position perpendicular to the optical axis at a height r to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a10, a12, a14, a16, a18, a20 are the high-order aspheric coefficients of the corresponding aspheric surfaces of the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth, and twentieth orders, a i r i The combination becomes the high-order term of the corresponding aspheric surface. The even-order term coefficients of each aspheric surface in the above embodiment 1 are shown in Table 4:

[0158] Table 4 Aspheric parameters of each lens in the zoom lens of Example 1

[0159]

[0160] Among them, -1.456354798729E-05 means that the coefficient a4 of face number 8 is -1.456354798729*10 -5 , and so on.

[0161] The parameter indexes of the zoom lens in the first embodiment are shown in Table 5:

[0162] Table 5 Parameters of the zoom lens in Example 1

[0163] Wide angle Telephoto end Image size(mm) Φ13.1 Φ13.1 Focal length(mm) 9.60 28.50 distortion(%) -6.46％ 3.32％ Wavelength (nm) 436-656 436-656 Total optical length (mm) 90.00 90.00

[0164] Figure 3 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the utility model at the infinite object distance at the wide-angle end is shown as follows: Figure 4 This is the vertical axis chromatic aberration curve of the zoom lens provided by the first embodiment of the utility model at the wide-angle end with an object distance of 1m, where the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 3 , Figure 4 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different object distances at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0165] Figure 5 This is a light fan diagram of the zoom lens provided in the first embodiment of the utility model at the infinite object distance at the wide-angle end. Figure 6This is a light fan diagram of the zoom lens provided in Example 1 of the utility model at the wide-angle end at an object distance of 1m. First of all, the light fan diagram is one of the evaluation methods commonly used by optical designers. The horizontal axis in a single diagram is the normalized light beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 5 , Figure 6 It can be seen that the wavelengths of each field of view of this zoom lens at different object distances at the wide-angle end are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color do not have obvious dispersion, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0166] Figure 7 This is a field curvature distortion diagram of the zoom lens provided in Example 1 of the utility model at infinity at the wide-angle end. Figure 8 The field curvature distortion diagram of the zoom lens provided in the first embodiment of the utility model at the wide-angle end of 1m object distance. In the coordinate system on the left side of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; T represents the meridian, and S represents the arc loss; Figure 7 and Figure 8 It can be seen that the lens provided in this embodiment is effectively controlled in field curvature from light with a wavelength of 436nm to light with a wavelength of 656nm, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in units of %; the vertical coordinate represents the normalized image height, without units; Figure 7 and Figure 8 It can be seen that the distortion of the lens provided in this embodiment is well corrected, the imaging distortion is small, and the use requirements of the zoom lens are met.

[0167] Fig. 9 The axial aberration curve of the zoom lens provided in the first embodiment of the utility model at infinity at the wide-angle end is as follows: Fig.10 This is the axial aberration curve of the zoom lens provided in Example 1 of the utility model at the wide-angle end at an object distance of 1m, where the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength in millimeters (mm). Fig. 9 , Fig.10 It can be seen that the axial aberrations of normalized apertures of different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of the zoom lens at the wide-angle end are well controlled and meet the usage requirements.

[0168] Fig.11 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end is as follows: Fig.12 This is the vertical axis chromatic aberration curve of the zoom lens provided by the first embodiment of the utility model at the telephoto end of 1m object distance, where the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Fig.11 , Fig.12 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different object distances at the telephoto end is well controlled and can meet the application requirements under normal conditions.

[0169] Fig.13 This is a light fan diagram of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end, Fig.14 This is a light fan diagram of the zoom lens at the telephoto end at an object distance of 1m provided in Example 1 of the utility model. First of all, the light fan diagram is one of the evaluation methods commonly used by optical designers. The horizontal axis in a single diagram is the normalized light beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.13 , Fig.14 It can be seen that the wavelengths of each field of view of this zoom lens at different object distances at the telephoto end are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0170] Fig.15 This is a field curvature distortion diagram of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end. Fig.16 The field curvature distortion diagram of the zoom lens provided in the first embodiment of the utility model at the telephoto end of 1m object distance, in the left coordinate system of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, the unit is mm; the vertical coordinate represents the normalized image height, no unit; wherein T represents the meridian, S represents the arc loss; Fig.15 and Fig.16It can be seen that the lens provided in this embodiment is effectively controlled in field curvature from light with a wavelength of 436nm to light with a wavelength of 656nm, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in units of %; the vertical coordinate represents the normalized image height, without units; Fig.15 and Fig.16 It can be seen that the distortion of the lens provided in this embodiment is well corrected, the imaging distortion is small, and the use requirements of the zoom lens are met.

[0171] Fig.17 The axial aberration curve of the zoom lens provided in the first embodiment of the utility model at infinity at the telephoto end is as follows: Fig.18 This is the axial aberration curve of the zoom lens provided in the first embodiment of the utility model at the telephoto end at an object distance of 1m, where the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength in millimeters (mm). Fig.17 , 18 It can be seen that the axial aberrations of normalized apertures of different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of the zoom lens at the telephoto end are well controlled and meet the usage requirements.

[0172] Fig.19 This is a schematic diagram of the structure of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end. Fig. 20 This is a schematic diagram of the structure of the zoom lens provided in the second embodiment of the utility model at the telephoto end at an object distance of 1m, referring to Fig.19 and Fig. 20 , the parameter design values ​​of each lens in the zoom lens of the second embodiment are shown in Table 6:

[0173] Table 6 Design values ​​of each lens in the zoom lens in Example 2

[0174]

[0175]

[0176] The surface numbers in Table 6 are numbered according to the order of the surfaces of each lens; among them, "STO" represents the aperture of the zoom lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "INF" indicates that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light. The zoom interval values ​​in Table 6 above are shown in Table 7:

[0177] Table 7 A design value of the zoom interval of the zoom lens at the wide-angle end and the telephoto end in Example 2

[0178] Wide-angle end Telephoto end Zoom interval 1 0.060 15.816 Zoom interval 2 18.586 1.143 Zoom interval 3 6.990 6.158 Zoom interval 4 4.521 7.040

[0179] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0180]

[0181] Wherein, Z is the axial distance from the curved surface at a position perpendicular to the optical axis at a height r to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a10, a12, a14, a16, a18, a20 are the high-order aspheric coefficients of the corresponding aspheric surfaces of the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth, and twentieth orders, a i r i The even-order coefficients of each aspherical surface in the above-mentioned embodiment 2 are shown in Table 8:

[0182] Table 8 Aspheric parameters of each lens in the zoom lens of Example 2

[0183]

[0184]

[0185] Among them, -1.717816917979E-05 means that the coefficient a4 of face number 8 is -1.717816917979*10 -5 , and so on.

[0186] The parameter indicators of the zoom lens in the second embodiment are shown in Table 9:

[0187] Table 9 Parameters of the zoom lens in Example 2

[0188] Wide-angle end Telephoto end Image size(mm) Φ13.1 Φ13.1 Focal length(mm) 10.00 26.96 distortion(%) -3.63 3.70 Wavelength(nm) 436-656 436-656 Total optical length (mm) 90.00 90.00

[0189] Fig.21 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end is as follows: Fig. 22 This is the vertical axis chromatic aberration curve of the zoom lens provided by the second embodiment of the utility model at the wide-angle end with an object distance of 1m, where the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Fig.21 , Fig. 22 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different object distances at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0190] Fig.23 This is a light fan diagram of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end. Fig.24 This is a light fan diagram of the zoom lens at the wide-angle end at an object distance of 1m provided in Example 2 of the utility model. First of all, the light fan diagram is one of the evaluation methods commonly used by optical designers. The horizontal axis in a single diagram is the normalized light beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.23 , Fig.24 It can be seen that the wavelengths of each field of view of this zoom lens at different object distances at the wide-angle end are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color do not have obvious dispersion, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0191] Fig.25 This is a field curvature distortion diagram of the zoom lens provided in Example 2 of the utility model at infinity at the wide-angle end. Fig.26 This is a field curvature distortion diagram of the zoom lens provided by the second embodiment of the utility model at the wide-angle end of 1m object distance. In the coordinate system on the left side of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; T represents the meridian, and S represents the arc loss; Fig.26 and Fig.26 It can be seen that the lens provided in this embodiment is effectively controlled in field curvature from light with a wavelength of 436nm to light with a wavelength of 656nm, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in units of %; the vertical coordinate represents the normalized image height, without units; Fig.25 and Fig.26 It can be seen that the distortion of the lens provided in this embodiment is well corrected, the imaging distortion is small, and the use requirements of the zoom lens are met.

[0192] Fig. 27 The axial aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the wide-angle end is as follows: Fig.28 This is the axial aberration curve of the zoom lens provided in Example 2 of the utility model at the wide-angle end at an object distance of 1m, where the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength in millimeters (mm). Fig. 27 , 28 It can be seen that the axial aberrations of normalized apertures of different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of the zoom lens at the wide-angle end are well controlled and meet the usage requirements.

[0193] Fig.29 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end is: Fig.30 This is the vertical axis chromatic aberration curve of the zoom lens provided by the second embodiment of the utility model at the telephoto end of 1m object distance, where the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Fig.29 , Fig.30 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different object distances at the telephoto end is well controlled and can meet the application requirements under normal conditions.

[0194] Fig.31 This is a light fan diagram of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end. Fig.32 This is a light fan diagram of the zoom lens at the telephoto end at an object distance of 1m provided in Example 2 of the utility model. First of all, the light fan diagram is one of the evaluation methods commonly used by optical designers. The horizontal axis in a single diagram is the normalized light beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, at which time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.31 , Fig.32It can be seen that the wavelengths of each field of view of this zoom lens at different object distances at the telephoto end are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0195] Fig.33 This is a field curvature distortion diagram of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end. Fig.34 This is a field curvature distortion diagram of the zoom lens provided by the second embodiment of the utility model at the telephoto end of 1m object distance. In the coordinate system on the left side of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; T represents the meridian, and S represents the arc loss; Fig.33 and Fig.34 It can be seen that the lens provided in this embodiment is effectively controlled in field curvature from light with a wavelength of 436nm to light with a wavelength of 656nm, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in units of %; the vertical coordinate represents the normalized image height, without units; Fig.33 and Fig.34 It can be seen that the distortion of the lens provided in this embodiment is well corrected, the imaging distortion is small, and the use requirements of the zoom lens are met.

[0196] Fig.35 The axial aberration curve of the zoom lens provided in the second embodiment of the utility model at infinity at the telephoto end is: Fig.36 This is the axial aberration curve of the zoom lens provided in Example 2 of the utility model at the telephoto end at an object distance of 1m. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Fig.35 , Fig.36 It can be seen that the axial aberrations of normalized apertures of different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of the zoom lens at the telephoto end are well controlled and meet the usage requirements.

[0197] Fig.37 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided in Embodiment 3 of the present utility model. Fig.38 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by the third embodiment of the present utility model, referring to Fig.37 and Fig.38 , the parameter design values ​​of each lens in the zoom lens of the third embodiment are shown in Table 10:

[0198] Table 10: Design values ​​of each lens in the zoom lens in Example 3

[0199]

[0200]

[0201]

[0202] The surface numbers in Table 10 are numbered according to the order of the surfaces of each lens; among them, "STO" represents the aperture of the zoom lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "INF" indicates that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light. The zoom interval values ​​in Table 10 above are shown in Table 11:

[0203] Table 11 A design value of the zoom interval of the zoom lens at the wide-angle end and the telephoto end in Example 3

[0204] Wide-angle end Telephoto end Zoom interval 1 0.443 16.494 Zoom interval 2 18.763 0.098 Zoom interval 3 6.598 6.190 Zoom interval 4 4.075 7.097

[0205] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0206]

[0207] Wherein, Z is the axial distance from the curved surface at a position perpendicular to the optical axis at a height r to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a10, a12, a14, a16, a18, a20 are the high-order aspheric coefficients of the corresponding aspheric surfaces of the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth, and twentieth orders, a i r i The even-order coefficients of the aspherical surfaces in the third embodiment are shown in Table 12:

[0208] Table 12 Aspheric parameters of each lens in the zoom lens of Example 3

[0209]

[0210] Among them, -1.752134202673E-05 means that the coefficient a4 of face number 8 is -1.752134202673*10 -5 , and so on.

[0211] The parameter indicators of the zoom lens in the third embodiment are shown in Table 13:

[0212] Table 13 Parameters of the zoom lens in Example 3

[0213]

[0214]

[0215] Fig.39 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end is as follows: Fig.40 This is the vertical axis chromatic aberration curve of the zoom lens provided by the third embodiment of the utility model at the wide-angle end with an object distance of 1m, where the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Fig.39 , Fig.40 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different object distances at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0216] Fig.41 This is a light fan diagram of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end. Fig.42 This is a light fan diagram of the zoom lens provided in Example 3 of the utility model at the wide-angle end at an object distance of 1m. First of all, the light fan diagram is one of the evaluation methods commonly used by optical designers. The horizontal axis in a single diagram is the normalized light beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.41 , Fig.42 It can be seen that the wavelengths of each field of view of this zoom lens at different object distances at the wide-angle end are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color do not have obvious dispersion, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0217] Fig.43 This is a field curvature distortion diagram of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end. Fig.44 This is a field curvature distortion diagram of the zoom lens provided by the third embodiment of the utility model at the wide-angle end of 1m object distance. In the coordinate system on the left side of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; T represents the meridian, and S represents the arc loss; Fig.43 and Fig.44 It can be seen that the lens provided in this embodiment is effectively controlled in field curvature from light with a wavelength of 436nm to light with a wavelength of 656nm, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in units of %; the vertical coordinate represents the normalized image height, without units; Fig.43 and Fig.44 It can be seen that the distortion of the lens provided in this embodiment is well corrected, the imaging distortion is small, and the use requirements of the zoom lens are met.

[0218] Fig.45 The axial aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the wide-angle end is: Fig.46 This is the axial aberration curve of the zoom lens provided by the third embodiment of the utility model at the wide-angle end at an object distance of 1m, where the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength in millimeters (mm). Fig.45 , 46 It can be seen that the axial aberrations of normalized apertures of different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of the zoom lens at the wide-angle end are well controlled and meet the usage requirements.

[0219] Fig.47 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the telephoto end is: Fig.48 This is the vertical axis chromatic aberration curve of the zoom lens provided by the third embodiment of the utility model at the telephoto end of 1m object distance, where the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Fig.47 , Fig.48 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different object distances at the telephoto end is well controlled and can meet the application requirements under normal conditions.

[0220] Fig.49 This is a light fan diagram of the zoom lens provided in the third embodiment of the utility model at the infinite telephoto end. Fig.50This is a light fan diagram of the zoom lens at the telephoto end at an object distance of 1m provided in Example 3 of the utility model. First of all, the light fan diagram is one of the evaluation methods commonly used by optical designers. The horizontal axis in a single diagram is the normalized light beam diameter, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis. At this time, all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.49 , Fig.50 It can be seen that the wavelengths of each field of view of this zoom lens at different object distances at the telephoto end are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0221] Fig.51 This is a field curvature distortion diagram of the zoom lens provided in the third embodiment of the utility model at infinity at the telephoto end. Fig.52 This is a field curvature distortion diagram of the zoom lens provided by the third embodiment of the present invention at the telephoto end of 1m object distance. In the coordinate system on the left side of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, in mm; the vertical coordinate represents the normalized image height, without unit; T represents the meridian, S represents the arc loss; Fig.51 and Fig.52 It can be seen that the lens provided in this embodiment is effectively controlled in field curvature from light with a wavelength of 436nm to light with a wavelength of 656nm, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in units of %; the vertical coordinate represents the normalized image height, without units; Fig.51 and Fig.52 It can be seen that the distortion of the lens provided in this embodiment is well corrected, the imaging distortion is small, and the use requirements of the zoom lens are met.

[0222] Fig.53 The axial aberration curve of the zoom lens provided in the third embodiment of the utility model at infinity at the telephoto end is: Fig.54 This is the axial aberration curve of the zoom lens provided by the third embodiment of the utility model at the telephoto end of 1m object distance, where the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Fig.53 , Fig.54 It can be seen that the axial aberrations of normalized apertures of different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of the zoom lens at the telephoto end are well controlled and meet the usage requirements.

[0223] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A zoom lens, characterized in that: The lens comprises a first fixed lens group with positive focal power, a first variable-power lens group with negative focal power, an aperture, a second variable-power lens group with positive focal power, a focusing lens group with positive focal power, and a second fixed lens group with negative focal power, which are arranged in sequence from the object side to the image side along the optical axis; The first fixed lens group includes a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power; The first variable power lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power; The second variable power lens group includes a seventh lens with negative optical power, an eighth lens with positive optical power, a ninth lens with positive optical power, and a tenth lens with negative optical power; The focusing lens group includes an eleventh lens with positive optical power, a twelfth lens with positive optical power, and a thirteenth lens with negative optical power; The second fixed lens group includes a fourteenth lens having positive optical power; The first variable-power lens group, the second variable-power lens group, the focusing lens group and the second fixed lens group each include at least one aspherical lens; During the magnification change process, the positions of the first fixed lens group and the second fixed lens group are fixed, the first magnification change lens group and the second magnification change lens group move along the optical axis to change the magnification, and the focusing lens group moves along the optical axis to focus.

2. The zoom lens according to claim 1, wherein: The fifth lens is an aspherical lens; The seventh lens is an aspherical lens; The eleventh lens is an aspherical lens; The fourteenth lens is an aspherical lens.

3. The zoom lens according to claim 1, wherein: The focal length F1 of the first fixed lens group, the focal length F2 of the first variable-power lens group, the focal length F3 of the second variable-power lens group, the focal length F4 of the focusing lens group, the focal length F5 of the second fixed lens group and the wide-angle end focal length FW of the zoom lens satisfy the following condition: 44.14≤F1 / FW≤45.51; -25.22≤F2 / FW≤-24.86; 31.70≤F3 / FW≤35.89; 9.94≤F4 / FW≤11.49; 56.32≤F5 / FW≤71.

72.

4. The zoom lens according to claim 1, wherein: The first lens is a convex-concave type, the second lens is a convex-convex type, and the third lens is a convex-concave type; The fourth lens is a convex-concave type, the fifth lens is a concave-concave type, and the sixth lens is a convex-convex type; The seventh lens is of concave-concave type, the eighth lens is of convex-convex type, the ninth lens is of convex-convex type, and the tenth lens is of concave-concave type; The eleventh lens is of convex-convex type, the twelfth lens is of convex-convex type, and the thirteenth lens is of concave-concave type; In the second fixed lens group, the fourteenth lens is of convex-concave type.

5. The zoom lens according to claim 1, wherein: The first fixed lens group includes at least one cemented lens group, and / or the second variable power lens group includes at least one cemented lens group, and / or the focusing lens group includes at least one cemented lens group.

6. The zoom lens according to claim 1, wherein: The materials of the fifth lens, the seventh lens, the eleventh lens and the fourteenth lens meet the following conditions: 1.49≤nd5≤1.59;67.0≤vd5≤81.6; 1.44≤nd7≤1.59;68.6≤vd7≤95.1; 1.49≤nd11≤1.51;64.8≤vd11≤81.6; 1.78≤nd14≤1.89;26.9≤vd14≤50.3; Among them, nd5, nd7, nd11, and nd14 respectively represent the refractive indices of the fifth lens, the seventh lens, the eleventh lens, and the fourteenth lens, and vd5, vd7, vd11, and vd14 respectively represent the Abbe numbers of the fifth lens, the seventh lens, the eleventh lens, and the fourteenth lens.

7. The zoom lens according to claim 1, wherein: The second variable power lens group and the focus lens group satisfy the following condition: 1.156≤S3 / S4≤1.493; Among them, S2 is the maximum distance that the first zoom lens group can move, and S4 is the maximum distance that the focus lens group can move.

8. The zoom lens according to claim 1, wherein: The focal lengths of the wide-angle end and the telephoto end of the zoom lens must meet the following conditions: 2.69≤FT / FW≤2.97; Wherein, FW represents the focal length of the zoom lens at the wide-angle end, and FT represents the focal length of the zoom lens at the telephoto end.

9. The zoom lens according to claim 1, wherein: The zoom lens meets the following conditions: 5.24≤TTL / S2≤5.68; Wherein, TTL represents the total optical length of the zoom lens, and S2 represents the maximum distance that the first zoom lens group can move.

10. The zoom lens according to claim 1, wherein: The zoom lens meets the following conditions: 1.15 <FNO<1.25; Wherein, FNO is the aperture number of the zoom lens at the full focal length.

Images