Zoom lens

Abstract

The zoom lens comprises a first fixed lens group, a zoom lens group, a diaphragm, a second fixed lens group, a focusing lens group and a third fixed lens group which are sequentially arranged from an object plane to an image plane along an optical axis, and the focal powers are respectively positive, negative, positive, positive, positive or negative; the first fixed lens group consists of three lenses, and the focal powers of the three lenses are respectively negative, positive and positive; the zoom lens group is composed of four lenses, and the focal power of the four lenses is negative, negative, positive and negative. The second fixed lens group consists of three lenses, and the focal powers of the three lenses are respectively positive, negative and positive; the focusing lens group consists of four lenses, and the focal powers are respectively positive, negative, positive and negative; the third fixed lens group consists of two lenses, and the focal powers of the two lenses are respectively positive and negative; each of the focusing lens group, the second fixed lens group and the third fixed lens group at least comprises an aspheric lens. The zoom lens can meet the use requirements of large aperture, high and low temperature confocal and 4K clear imaging on a 1 / 1.2 ''target surface and at the wave band of 436-870nm.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of optical devices, and in particular to a zoom lens. Background Art

[0002] ITS (Intelligent Traffic System, ITS) lens is a lens specially designed for image sensors. Among them, most of the ITS lenses commonly used on the market are fixed-focus lenses, with low image quality and poor tolerance in harsh environments; facing more complex usage environments, zoom lenses have gradually become the new favorite in the ITS field, but the types of zoom lenses for the ITS field on the market are extremely limited, and there are problems such as low image quality, too small focal length range, and small temperature application range, which have certain difficulties in practical application. Therefore, it is particularly necessary to develop a zoom lens with large aperture, high definition, wide temperature application range, and long focal length that meets the needs of ITS. Summary of the invention

[0003] The present invention provides a zoom lens, which can meet the use requirements of large aperture, high and low temperature confocality, and 4K clear imaging on a 1 / 1.2″ target surface and in a 436nm-870nm band.

[0004] An embodiment of the present invention provides a zoom lens, comprising a first fixed lens group with positive optical power, a variator lens group with negative optical power, an aperture, a second fixed lens group with positive optical power, a focus lens group with positive optical power, and a third fixed lens group with positive optical power or negative optical power, which are arranged in sequence from an object plane to an image plane along an optical axis; the first fixed lens group, the second fixed lens group, and the third fixed lens group are fixed, and the variator lens group and the focus lens group move along the optical axis direction during zooming;

[0005] 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;

[0006] The variable power lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, a sixth lens with positive optical power and a seventh lens with negative optical power;

[0007] The second fixed lens group includes an eighth lens with positive optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power; the second fixed lens group includes at least one aspherical lens;

[0008] The focusing lens group includes an eleventh lens with positive optical power, a twelfth lens with negative optical power, a thirteenth lens with positive optical power and a fourteenth lens with negative optical power; the focusing lens group includes at least one aspherical lens;

[0009] The third fixed lens group includes a fifteenth lens with positive optical power and a sixteenth lens with negative optical power; the third fixed lens group includes at least one aspherical lens.

[0010] Optionally, along the direction from the object side to the image side of the optical axis, the surface of the lens close to the object plane is the object side surface, and the surface of the lens close to the image plane is the image side surface;

[0011] In the first fixed lens group, the surface shape of the first lens is convex-concave; the object side surface of the second lens is convex; and the surface shape of the third lens is convex-concave;

[0012] In the variable power lens group, the surface shape of the fourth lens is convex-concave, the surface shape of the fifth lens is concave-concave, the surface shape of the sixth lens is convex-concave, and the surface shape of the seventh lens is concave-convex;

[0013] In the second fixed lens group, the surface shape of the eighth lens is convex-convex, the surface shape of the ninth lens is concave-concave, and the surface shape of the tenth lens is convex-convex;

[0014] In the focusing lens group, the surface shape of the eleventh lens is convex-convex, the surface shape of the twelfth lens is convex-concave, the surface shape of the thirteenth lens is convex-convex, and the surface shape of the fourteenth lens is concave-concave;

[0015] In the third fixed lens group, the image side surface of the fifteenth lens is convex, and the surface shape of the sixteenth lens is concave-concave.

[0016] Optionally, the zoom lens has a consistent aperture position relative to the image plane position at different focal lengths, and the aperture diameters are the same at different focal lengths, satisfying: FNO≤1.50;

[0017] Wherein, FNO is the aperture size of the zoom lens at different focal lengths.

[0018] Optionally, the eighth lens is a glass aspheric lens; the eleventh lens is a glass aspheric lens; the sixteenth lens is a plastic aspheric lens, and the third fixed lens group further includes a seventeenth lens with zero optical power.

[0019] Optional, 6.65≤F1 / FW≤-7.63; -2.13≤F2 / FW≤-1.93; 6.21≤F3 / FW≤6.31;

[0020] 1.98≤F4 / FW≤2.22; 42.62≤F5 / FW≤72.90;

[0021] Among them, F1, F2, F3, F4, and F5 are the focal lengths of the first fixed lens group, the variable power lens group, the second fixed lens group, the focusing lens group, and the third fixed lens group respectively; and FW is the focal length of the wide-angle end of the zoom lens.

[0022] Optional, 11.28≤S2 / S4≤15.89;

[0023] Among them, S2 is the maximum distance that the zoom lens group moves along the optical axis direction, and S4 is the maximum distance that the focus lens group moves along the optical axis direction.

[0024] Optional, 1.50≤nd8≤1.61; 57.74≤vd8≤81.58; 1.44≤nd11≤1.55;

[0025] 71.68≤vd11≤95.12;1.64≤nd16≤1.66;20.38≤vd16≤23.5;

[0026] Among them, nd8, nd11, and nd16 represent the refractive indices of the eighth lens, the eleventh lens, and the sixteenth lens respectively, and vd8, vd11, and vd16 represent the Abbe numbers of the eighth lens, the eleventh lens, and the sixteenth lens respectively.

[0027] Optionally, the first lens and the second lens are combined into a doublet lens group.

[0028] Optionally, the fifth lens and the sixth lens of the variable power lens group are combined into a double cemented lens group, which satisfies:

[0029] -5.94≤F5-6 / F2q≤-4.88;

[0030] Among them, F5-6 represents the focal length of the double-cemented lens group, and F2q represents the focal length of the second fixed lens group.

[0031] Optionally, the ninth lens and the tenth lens of the second fixed lens group are combined into a double cemented lens group, satisfying:

[0032] -1.53≤F9-10 / F3q≤-1.18;

[0033] Among them, F9-10 represents the focal length of the double-cemented lens group, and F3q represents the focal length of the second fixed lens group.

[0034] Optionally, the twelfth lens, the thirteenth lens and the fourteenth lens of the focusing lens group are combined into a triplet lens group, satisfying: -2.13≤F12-14 / F4q≤-1.56;

[0035] Among them, F12-14 represents the focal length of the triplet lens group, and F4q represents the focal length of the focusing lens group.

[0036] Optional, 32.90≤TTL / S4≤50.60;

[0037] Wherein, TTL represents the total length of the zoom lens, and S4 represents the maximum distance that the focus lens group moves along the optical axis direction.

[0038] The zoom lens provided by the embodiment of the present invention comprises a first fixed lens group, a variable power lens group, an aperture, a second fixed lens group, a focus lens group, and a third fixed lens group, which are arranged in sequence from the object plane to the image plane along the optical axis, and the optical powers are respectively positive, negative, positive, positive, positive or negative; the first fixed lens group is composed of three lenses, and the optical powers are respectively negative, positive and positive; the variable power lens group is composed of four lenses, and the optical powers are respectively negative, negative, positive and negative; the second fixed lens group is composed of three lenses, and the optical powers are respectively positive, negative and positive; the focus lens group is composed of four lenses, and the optical powers are respectively positive, negative, positive and negative; the third fixed lens group is composed of two lenses, and the optical powers are respectively positive and negative; the focus lens group, the second fixed lens group and the third fixed lens group each include at least one aspherical lens. The zoom lens can meet the use requirements of large aperture, high and low temperature confocality, and 4K clear imaging on a 1 / 1.2" target surface and in the 436nm-870nm band. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of a zoom lens at the wide-angle end provided by the present invention;

[0040] Figure 2 A schematic diagram of the structure of a zoom lens at the telephoto end provided by the present invention;

[0041] Figure 3 A schematic diagram of the structure of the zoom lens at the wide-angle end provided in the first embodiment of the present invention;

[0042] Figure 4 A schematic diagram of the structure of the zoom lens at the telephoto end provided by the first embodiment of the present invention;

[0043] Figure 5 for Figure 3 The modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end is provided;

[0044] Figure 6 for Figure 3 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end;

[0045] Figure 7 for Figure 3The modulation transfer function curve of the zoom lens in the wide-angle infrared band is provided;

[0046] Figure 8 for Figure 3 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the wide-angle end;

[0047] Fig. 9 for Figure 3 The modulation transfer function curve of the zoom lens at high temperature at the wide angle end is provided;

[0048] Fig.10 for Figure 3 Provided is the defocus modulation transfer function curve of the zoom lens at high temperature at the wide angle end;

[0049] Fig.11 for Figure 3 The modulation transfer function curve of the zoom lens at the wide-angle end and low temperature is provided;

[0050] Fig.12 for Figure 3 Provided is the defocus modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state;

[0051] Fig.13 for Figure 4 The modulation transfer function curve of the zoom lens in the visible light band at the telephoto end is provided;

[0052] Fig.14 for Figure 4 Provided is the defocus modulation transfer function curve of the zoom lens in the visible light band at the telephoto end;

[0053] Fig.15 for Figure 4 The modulation transfer function curve of the zoom lens in the infrared band at the telephoto end is provided;

[0054] Fig.16 for Figure 4 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end;

[0055] Fig.17 for Figure 4 The modulation transfer function curve of the zoom lens at the telephoto end and high temperature is provided;

[0056] Fig.18 for Figure 4 Provided is the defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature;

[0057] Fig.19 for Figure 4 The modulation transfer function curve of the zoom lens at the telephoto end at low temperature is provided;

[0058] Fig. 20 for Figure 4 Provided is the defocus modulation transfer function curve of the zoom lens at the telephoto end at low temperature;

[0059] Fig.21 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 2 of the present invention;

[0060] Fig. 22 A schematic diagram of the structure of a zoom lens at the telephoto end provided by Embodiment 2 of the present invention;

[0061] Fig.23 for Fig.21 The modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end is provided;

[0062] Fig.24 for Fig.21 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end;

[0063] Fig.25 for Fig.21 The modulation transfer function curve of the zoom lens in the wide-angle infrared band is provided;

[0064] Fig.26 for Fig.21 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the wide-angle end;

[0065] Fig. 27 for Fig.21 The modulation transfer function curve of the zoom lens at high temperature at the wide angle end is provided;

[0066] Fig.28 for Fig.21 Provided is the defocus modulation transfer function curve of the zoom lens at high temperature at the wide angle end;

[0067] Fig.29 for Fig.21 The modulation transfer function curve of the zoom lens at the wide-angle end and low temperature is provided;

[0068] Fig.30 for Fig.21 Provided is the defocus modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state;

[0069] Fig.31 for Fig. 22 The modulation transfer function curve of the zoom lens in the visible light band at the telephoto end is provided;

[0070] Fig.32 for Fig. 22 Provided is the defocus modulation transfer function curve of the zoom lens in the visible light band at the telephoto end;

[0071] Fig.33 for Fig. 22 The modulation transfer function curve of the zoom lens in the infrared band at the telephoto end is provided;

[0072] Fig.34 for Fig. 22 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end;

[0073] Fig.35 for Fig. 22 The modulation transfer function curve of the zoom lens at the telephoto end and high temperature is provided;

[0074] Fig.36 for Fig. 22 Provided is the defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature;

[0075] Fig.37 for Fig. 22 The modulation transfer function curve of the zoom lens at the telephoto end at low temperature is provided;

[0076] Fig.38 for Fig. 22 Provided is the defocus modulation transfer function curve of the zoom lens at the telephoto end at low temperature;

[0077] Fig.39 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 3 of the present invention;

[0078] Fig.40 A schematic diagram of the structure of a zoom lens at the telephoto end provided by Embodiment 3 of the present invention;

[0079] Fig.41 for Fig.39 The modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end is provided;

[0080] Fig.42 for Fig.39 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end;

[0081] Fig.43 for Fig.39 The modulation transfer function curve of the zoom lens in the wide-angle infrared band is provided;

[0082] Fig.44 for Fig.39 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the wide-angle end;

[0083] Fig.45 for Fig.39The modulation transfer function curve of the zoom lens at high temperature at the wide angle end is provided;

[0084] Fig.46 for Fig.39 Provided is the defocus modulation transfer function curve of the zoom lens at high temperature at the wide angle end;

[0085] Fig.47 for Fig.39 The modulation transfer function curve of the zoom lens at the wide-angle end and low temperature is provided;

[0086] Fig.48 for Fig.39 Provided is the defocus modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state;

[0087] Fig.49 for Fig.40 The modulation transfer function curve of the zoom lens in the visible light band at the telephoto end is provided;

[0088] Fig.50 for Fig.40 Provided is the defocus modulation transfer function curve of the zoom lens in the visible light band at the telephoto end;

[0089] Fig.51 for Fig.40 The modulation transfer function curve of the zoom lens in the infrared band at the telephoto end is provided;

[0090] Fig.52 for Fig.40 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end;

[0091] Fig.53 for Fig.40 The modulation transfer function curve of the zoom lens at the telephoto end and high temperature is provided;

[0092] Fig.54 for Fig.40 Provided is the defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature;

[0093] Fig.55 for Fig.40 The modulation transfer function curve of the zoom lens at the telephoto end at low temperature is provided;

[0094] Fig.56 for Fig.40 The provided defocus modulation transfer function curve of the zoom lens at the telephoto end and low temperature state. DETAILED DESCRIPTION

[0095] The present invention will be 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 parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0096] Figure 1 A schematic diagram of the structure of a zoom lens at the wide-angle end provided by the present invention, Figure 2 This is a schematic diagram of the structure of a zoom lens at the telephoto end provided by the present invention. Figure 1 and Figure 2 As shown, a zoom lens provided by an embodiment of the present invention includes a first fixed lens group G1 with positive optical focal length, a variator lens group G2 with negative optical focal length, an aperture STO, a second fixed lens group G3 with positive optical focal length, a focusing lens group G4 with positive optical focal length, and a third fixed lens group G5 with positive optical focal length or negative optical focal length, which are arranged in sequence along the optical axis from the object plane to the image plane; the first fixed lens group G1, the second fixed lens group G2 and the third fixed lens group G5 are fixed, and the variator lens group G3 and the focusing lens group G4 move along the optical axis when zooming.

[0097] Along the optical axis from the object plane to the image plane:

[0098] The first fixed lens group G1 includes a first lens L1 having negative power, a second lens L2 having positive power, and a third lens L3 having positive power.

[0099] The variator lens group G2 includes a fourth lens L4 having negative power, a fifth lens L5 having negative power, a sixth lens L6 having positive power, and a seventh lens L7 having negative power.

[0100] The second fixed lens group G3 includes an eighth lens L8 with positive optical power, a ninth lens L9 with negative optical power, and a tenth lens L10 with positive optical power; the second fixed lens group G3 includes at least one aspherical lens.

[0101] The focusing lens group G4 includes an eleventh lens L11 with positive optical power, a twelfth lens L12 with negative optical power, a thirteenth lens L13 with positive optical power and a fourteenth lens L14 with negative optical power; the focusing lens group G4 includes at least one aspherical lens.

[0102] The third fixed lens group G5 includes a fifteenth lens L15 with positive optical power and a sixteenth lens L16 with negative optical power; the third fixed lens group G5 includes at least one aspherical lens.

[0103] Specifically, refer to Figure 1 and Figure 2As shown, in the zoom lens provided in the embodiment of the present application, the first fixed lens group G1, the variable magnification lens group G2, the second fixed lens group G3, the focus lens group G4 and the third fixed lens group G5 can be arranged in a lens barrel ( Figure 1 and Figure 2 The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in the lens barrel. At this time, the first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are immovable relative to the image plane IMA. The zoom lens group G2 and the focus lens group G4 can move back and forth along the optical axis in the lens barrel. Moving the zoom lens group G2 can play a role in zooming, and moving the focus lens group G4 can focus on the image. On the one hand, it can compensate for the aberration caused by the zoom movement of the zoom lens group G2 and effectively achieve the aberration balance of each focal length. On the other hand, it adjusts the distance between the lens and the object or the imaging plane to ensure the clear imaging of the object under different focal lengths. Through the joint movement of the zoom lens group G2 and the focus lens group G4, the focal length of the zoom lens can be continuously changed from wide angle to telephoto.

[0104] It can be understood that when the zoom lens achieves zooming by moving the variable magnification lens group G2 and the focusing lens group G4, the zoom lens is located at the wide-angle end when the focal length is short, and is located at the telephoto end when the focal length is longest. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical focal powers, and also has different shapes.

[0105] It should be noted that Figure 1 , Figure 2 The structural schematic diagrams corresponding to the subsequent embodiments are only structural illustrations, and the shapes such as aspherical surfaces are not represented according to the actual situation.

[0106] Furthermore, the focal power is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam. Its value is the reciprocal of the focal length, and it characterizes the ability of the zoom lens 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, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0107] Among them, along the direction from the object plane to the image plane along the optical axis, the surface of the lens adjacent to the object plane is the object side surface, and the surface of the lens adjacent to the image plane is the image side surface.

[0108] In one embodiment of the present application, refer to Figure 1 and Figure 2The first fixed lens group G1 is composed of at least three lenses arranged in sequence from the object plane to the image plane along the optical axis. Among them, the optical power of the first lens L1 is negative, the optical power of the second lens L2 is positive, and the optical power of the third lens L3 is positive.

[0109] The zoom lens group G2 is composed of at least four lenses arranged in sequence from the object plane to the image plane along the optical axis, wherein the fourth lens L4 has a negative focal length, the fifth lens L5 has a negative focal length, the sixth lens L6 has a positive focal length, and the seventh lens L7 has a negative focal length.

[0110] The second fixed lens group G3 is composed of at least three lenses arranged in sequence from the object plane to the image plane along the optical axis. Among them, the optical power of the eighth lens L8 is positive, the optical power of the ninth lens L9 is negative, and the optical power of the tenth lens L10 is positive. The second fixed lens group G3 includes at least one aspherical lens. When the light passes through the aperture STO, the use of aspherical lenses can well correct the aberration difference, avoid the situation where the aberration is superimposed at the rear end of the lens and the rear end is difficult to pull back, and can effectively improve the image quality.

[0111] The focusing lens group G4 is composed of at least four lenses arranged in sequence from the object plane to the image plane along the optical axis. Among them, the optical power of the eleventh lens L11 is positive, the optical power of the twelfth lens L12 is negative, the optical power of the thirteenth lens L13 is positive, and the optical power of the fourteenth lens L14 is negative. The focusing lens group G4 includes at least one aspherical lens.

[0112] The third fixed lens group G5 is composed of at least two lenses arranged in sequence from the object plane to the image plane along the optical axis, wherein the optical power of the fifteenth lens L15 is positive, the optical power of the sixteenth lens L16 is negative, and the third fixed lens group G5 includes at least one aspherical lens.

[0113] In the embodiment of the present application, the aspherical lens of the zoom lens satisfies the following formula:

[0114]

[0115] Where Z is the axial distance from the curved surface at a height r perpendicular to the optical axis 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, and a14 are the high-order aspheric coefficients of the corresponding aspheric surfaces of the fourth, sixth, eighth, tenth, twelfth, and fourteenth order, a i r i The combination becomes the high-order terms corresponding to the aspheric surface, i=4, 6, 8, 10, 12, 14.

[0116] Among them, the aperture OTS includes an aperture aperture and a field aperture. The aperture aperture refers to the aperture that limits the light beam the most, and the field aperture refers to the aperture that limits the field of view (size) the most.

[0117] Reference Figure 1 and Figure 2 The front end of the aperture STO uses the first fixed lens group G1 with positive focal length and the variable magnification lens group G2 with negative focal length, which can ensure that a larger light aperture is generated after the light passes through, increase the aperture number of the zoom lens, and meet the use requirements under different conditions. The second fixed lens group G3 with positive focal length, the focusing lens group G4 with positive focal length, and the third fixed lens group G5 with positive or negative focal length used at the rear end of the aperture STO can correct the aberration at the rear end of the lens, and cooperate with the lens group at the front end of the aperture STO to stabilize the imaging quality of the zoom lens.

[0118] Specifically, the aperture STO is set between the seventh lens L7 with negative focal power and the eighth lens L8 with positive focal power, which can adjust the propagation direction of the light beam emitted by the seventh lens L7 to the incident surface of the eighth lens L8, thereby limiting the light beam or field of view in the zoom lens, thereby improving the imaging quality of the zoom lens. In this way, by changing the position of the zoom lens group G2 and the focus lens group G4 on the optical axis, the zoom lens can be switched between the wide-angle end and the telephoto end at any time.

[0119] The embodiment of the present application reasonably allocates the number of lenses of the first fixed lens group G1, the zoom lens group G2, the second fixed lens group G3, the focusing lens group G4 and the third fixed lens group G5, as well as the optical focal length of each lens, so that each lens group and the optical focal length of each lens cooperate with each other to compensate for the aberration caused by the zooming movement of the zoom lens group G2, thereby effectively achieving aberration balance in each focal length and ensuring image clarity at different focal lengths.

[0120] Figure 3 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided in Embodiment 1 of the present invention. Figure 4 This is a schematic structural diagram of a zoom lens at the telephoto end provided by Embodiment 1 of the present invention.

[0121] Based on the above embodiments, Figure 3-Figure 4 The eighth lens L8 is a glass aspherical lens; the eleventh lens L11 is a glass aspherical lens; the sixteenth lens L16 is a plastic aspherical lens, and the third fixed lens group G5 further includes a seventeenth lens L17 with zero optical power.

[0122] Specifically, refer to Figure 3-Figure 4 Glass lenses have a strong light-reflecting ability. Setting the eighth lens L8 and the eleventh lens L11 as glass aspherical lenses helps to reduce the number of lenses, thereby reducing the size of the lens.

[0123] The cost of plastic lenses is much lower than that of glass lenses. The sixteenth lens L16 can be a plastic aspherical lens, which can significantly reduce the cost of the zoom lens. The third fixed lens group G5 can also be provided with a seventeenth lens L17 as the last lens, which has zero optical power and can also be called a flat glass lens. This lens can well protect the sixteenth lens L16 and prevent the sixteenth lens L16 from being exposed outside the lens and being worn or dirty.

[0124] At the same time, glass and plastic can also compensate for each other and balance high and low temperatures, making the zoom lens stable in high and low temperature performance, which helps to improve the environmental adaptability of the zoom lens and is conducive to achieving the use requirements of large aperture, high and low temperature confocality, and 4K clear imaging on a 1 / 1.2″ target surface and in the 436nm-870nm band.

[0125] It should be noted that the material of other lenses can be glass or plastic, which is not limited here. The material of the plastic aspherical lens can be various plastics known to those skilled in the art, and the material of the glass spherical lens can be various types of glass known to those skilled in the art, which will not be elaborated or limited in the embodiments of the present invention.

[0126] Based on the above embodiments, Figure 1-Figure 4 , along the direction from the object side to the image side of the optical axis, the surface of the lens close to the object plane is the object side, and the surface of the lens close to the image plane is the image side.

[0127] In the first fixed lens group G1, the surface type of the first lens L1 is convex-concave; the object side surface of the second lens L2 is convex; and the surface type of the third lens L3 is convex-concave. In the zoom lens group G2, the surface type of the fourth lens L4 is convex-concave, the surface type of the fifth lens L5 is concave-concave, the surface type of the sixth lens L6 is convex-concave, and the surface type of the seventh lens L7 is concave-convex. In the second fixed lens group G3, the surface type of the eighth lens L8 is convex-convex, the surface type of the ninth lens L9 is concave-concave, and the surface type of the tenth lens L10 is convex-convex. In the focusing lens group G4, the surface type of the eleventh lens L11 is convex-convex, the surface type of the twelfth lens L12 is convex-concave, the surface type of the thirteenth lens L13 is convex-convex, and the surface type of the fourteenth lens L14 is concave-concave. In the third fixed lens group G5, the image-side surface of the fifteenth lens L15 is convex, and the surface type of the sixteenth lens L16 is concave-concave.

[0128] The concave lens has a diverging effect on the transmitted light, and the convex lens has a converging effect on the transmitted light. By properly setting the surface shapes of the first lens L1 to the sixteenth lens L16, clear imaging of the zoom lens at various focal lengths can be achieved.

[0129] Based on the above embodiments, Figure 1-Figure 4 , the first fixed lens group includes at least one cemented lens. For example, the first lens L1 and the second lens L2 are combined into a double cemented lens group. The air gap between the first lens L1 and the second lens L2 can be effectively reduced, and the total length of the zoom lens can be reduced; the double cemented lens group after the first lens L1 and the second lens L2 are glued together is a convex cemented negative lens, which is conducive to the smooth collection of object light into the imaging system, and can correct high-order aberrations to a large extent. At the same time, this shape can better collect light with a large field of view, ensuring the imaging requirements of a wide angle and a large field of view.

[0130] Among them, the glued lens group in the embodiment of the present application can also be called a glued lens.

[0131] Based on the above embodiments, Figure 1-Figure 4 The zoom lens group G2 includes at least one cemented lens, such as combining the fifth lens L5 and the sixth lens L6 into a double cemented lens group, and the focal length of the double cemented lens group and the focal length of the zoom lens group G2 satisfy the following relationship: -5.94≤F5-6 / F2q≤-4.88.

[0132] Wherein, F5-6 represents the focal length of the double cemented lens group composed of the fifth lens L5 and the sixth lens L6, and F2q represents the focal length of the second fixed lens group G3.

[0133] Specifically, by using the above-mentioned focal length combination in the double cemented lens group composed of the fifth lens L5 and the sixth lens L6 in the zoom lens group G2, light can pass smoothly through the middle end of the lens, and before the light enters the second fixed lens group G3, the use of cemented lenses can reduce the chromatic aberration and aberration generated at the front end, further improving the imaging quality.

[0134] At the same time, the combination of the double cemented lens group used in the first fixed lens group G1 and the double cemented lens group used in the zoom lens group G2 can also correct the high-order chromatic aberration and aberration of the lens, control the aberration balance of each group, and will not produce serious aberrations when the light enters the lens group behind the aperture STO, thereby improving the imaging quality of the zoom lens.

[0135] Based on the above embodiments, Figure 1-Figure 4 The ninth lens L9 and the tenth lens L10 of the second fixed lens group G3 are combined into a double cemented lens group, and the focal length of the double cemented lens group and the focal length of the second fixed lens group G3 satisfy the following relationship: -1.53≤F9-10 / F3q≤-1.18.

[0136] Wherein, F9-10 represents the focal length of a double cemented lens group composed of the ninth lens L9 and the tenth lens L10, and F3q represents the focal length of the second fixed lens group G3.

[0137] Specifically, by using the above-mentioned focal length combination of the double cemented lens group composed of the ninth lens L9 and the tenth lens L10 in the second fixed lens group G3, the light can pass through the middle end of the lens smoothly, and before the light enters the zoom lens group G4, the use of cemented lenses can reduce the chromatic aberration and aberration generated at the front end, further improving the imaging quality.

[0138] Based on the above embodiments, Figure 1-Figure 4 The twelfth lens L12, the thirteenth lens L13 and the fourteenth lens L14 of the focusing lens group G4 are combined into a triplet lens group, and the focal length of the triplet lens group and the focal length of the focusing lens group G4 need to satisfy the following relationship: -2.13≤F12-14 / F4q≤-1.56.

[0139] Among them, F12-14 represents the focal length of the triplet lens group, and F4q represents the focal length of the focusing lens group G4.

[0140] Specifically, during the zooming process of the zoom lens, the focus lens group G4 focuses the optical system with a changed focal length. The use of a triplet lens group can correct the chromatic aberration and higher-order aberrations generated in the focus lens group G4, greatly reducing the aberration pressure of other groups in the lens at different focal lengths, thereby achieving focusing of the zoom lens at the full focal length.

[0141] At the same time, the bonding setting can minimize or eliminate chromatic aberration, so that various aberrations of the zoom lens can be fully corrected. Under the premise of compact structure, it can improve resolution, optimize optical properties such as distortion, reduce light loss caused by reflection between lenses, and increase illumination, thereby improving image quality and improving the clarity of lens imaging. In addition, the bonding lens group can also reduce the number of assembly components between lenses, simplify the assembly procedures in the lens manufacturing process, reduce costs, and reduce the tolerance sensitivity of the lens unit due to tilt / eccentricity caused by the assembly process.

[0142] Based on the above embodiments, Figure 1-Figure 4 , the position of the aperture STO of the zoom lens at different focal lengths remains consistent relative to the image plane position, and the aperture diameter is the same at different focal lengths, and at the same time satisfies: FNO≤1.50. Among them, FNO is the aperture size of the zoom lens at different focal lengths.

[0143] Specifically, by controlling the aperture diameter of the aperture STO at different focal lengths to be the same, the aperture range is structurally reduced, ensuring that the movable group of the lens has a longer moving distance, and reducing the size of the zoom lens, a higher imaging magnification can be achieved at the same time to meet usage requirements under different conditions.

[0144] Based on the above embodiments, Figure 1-Figure 4 , the focal length of each lens group of the zoom lens and the focal length of the zoom lens at the wide-angle end satisfy the following relationship:

[0145] 6.65≤F1 / FW≤-7.63;-2.13≤F2 / FW≤-1.93;6.21≤F3 / FW≤6.31;

[0146] 1.98≤F4 / FW≤2.22; 42.62≤F5 / FW≤72.90;

[0147] Among them, F1, F2, F3, F4, and F5 are the focal lengths of the first fixed lens group G1, the zoom lens group G2, the second fixed lens group G3, the focus lens group G4, and the third fixed lens group G5 respectively; FW is the focal length of the zoom lens at the wide-angle end.

[0148] Specifically, matching the focal length of each lens group with the focal length of the wide-angle end of the zoom lens in the above-mentioned manner is conducive to achieving a reasonable combination of optical focal lengths, allowing light to pass through the lens more smoothly, and to a large extent correcting the impact of high-order aberrations on imaging quality.

[0149] Based on the above embodiments, Figure 1-Figure 4 , the moving distances of the zoom lens group G2 and the focus lens group G4 along the optical axis direction satisfy the following relationship: 11.28≤S2 / S4≤15.89.

[0150] Among them, S2 is the maximum distance that the zoom lens group G2 moves along the optical axis, and S4 is the maximum distance that the focus lens group G4 moves along the optical axis.

[0151] Specifically, by controlling the moving distance of the focusing lens group G4 and the second fixed lens group G3, the volume of the focusing lens group G4 can be reduced to the greatest extent, and stable imaging of the full focal length can be achieved within a smaller moving range. At the same time, the total volume of the zoom lens can be reduced to meet the requirements of lens miniaturization.

[0152] Based on the above embodiments, Figure 1-Figure 4 , the materials of the eighth lens L8, the eleventh lens L11, and the sixteenth lens L16 in the zoom lens meet the following requirements:

[0153] 1.50≤nd8≤1.61;57.74≤vd8≤81.58;

[0154] 1.44≤nd11≤1.55;71.68≤vd11≤95.12;

[0155] 1.64≤nd16≤1.66;20.38≤vd16≤23.5.

[0156] Among them, nd8, nd11, and nd16 respectively denote the refractive indices of the eighth lens L8, the eleventh lens L11, and the sixteenth lens L16, and vd8, vd11, and vd16 respectively denote the Abbe numbers of the eighth lens L8, the eleventh lens L11, and the sixteenth lens L16.

[0157] Specifically, in order to ensure stable imaging of the zoom lens at all focal lengths, it is usually necessary to achromatize and control the aberration of the fixed lens group separately to prevent the accumulation of chromatic aberration and aberration after entering the moving lens group and making it difficult to control, thereby affecting the image quality. In this application, the eighth lens L8 is matched with the materials of the above-mentioned lenses, which can control the chromatic aberration and aberration entering the focusing lens group G4 within a reasonable range, and avoid being over-magnified during the movement of the variable magnification lens group G3, which makes it difficult to correct later.

[0158] The use of the material combination of the eleventh lens L11 in the focus lens group G4 can further reduce the influence of the zoom lens group G3 on the chromatic aberration and aberration of the light. The sixteenth lens L16 uses the material combination of the above lens to correct the chromatic aberration and aberration produced by the entire lens and control it within a reasonable range before the light enters the image plane.

[0159] In addition, aspherical lenses have a good ability to control high-level aberrations of zoom lenses. The eighth lens L8, the eleventh lens L11, and the sixteenth lens L16 all use aspherical lenses, which can further reduce the high-level aberrations when light enters the image plane, so that the image quality can be further improved to meet the needs of 4K imaging.

[0160] In addition, the properties of glass lenses are not sensitive to temperature. The eighth lens L8 and the eleventh lens L11 use glass aspherical lenses, which can make the performance of the lens more uniform under different temperature conditions and have the characteristics of stable high and low temperature performance. And the sixteenth lens L16 uses plastic aspherical lenses, which can well compensate for the expansion / contraction of the lens frame under high and low temperatures, and improve the environmental adaptability of the zoom lens.

[0161] The introduction of glass aspherical lenses has also corrected the chromatic aberration and high-order aberrations of the lens to a great extent. Compared with plastic aspherical lenses, the range of options is also wider, and more diverse results can be used in structural selection, thereby improving the market competitiveness of the lens.

[0162] Based on the above embodiments, Figure 1-Figure 4 , the total length of the zoom lens and the moving distance of the focus lens group G4 satisfy the following relationship: 32.90≤TTL / S4≤50.60.

[0163] Wherein, TTL represents the total length of the zoom lens, and S4 represents the maximum distance that the focus lens group G2 moves along the optical axis.

[0164] Specifically, the limitation of the total length of the focus lens group G4 and the zoom lens can compress the lens space, ensuring that the lens can still obtain the required imaging quality and zoom ratio under the condition of small size.

[0165] refer to Figure 1-Figure 2 A flat glass L18 having a certain thickness is provided between the sixteenth lens L16 and the image plane IMA; Figure 3-Figure 4 A flat glass L18 with a certain thickness is arranged between the seventeenth lens L17 and the image plane IMA, which can not only play a protective role, but also filter out unnecessary stray light, thereby improving the imaging quality of the zoom lens. For example, the imaging quality of the zoom lens can be improved by filtering out infrared light during the day through the flat glass L18.

[0166] In summary, the zoom lens provided in the embodiment of the present invention can effectively achieve aberration balance in each focal length through reasonable matching of the optical power, refractive index, material, etc. of the five lens groups, ensure the clarity of the image under different focal lengths, and achieve the use requirements of large aperture, high and low temperature confocality, and 4K clear imaging on a target surface as large as 1 / 1.2" and in the 436nm-870nm band.

[0167] The zoom lens provided in the embodiment of the present application is applied in the ITS lens, which has the characteristics of high resolution, low distortion, high contrast, etc., and can provide clear, accurate, high-quality images. Its design takes into account the optical characteristics, mechanical structure and electronic interface, etc., and can effectively adapt to various complex environments.

[0168] Specific embodiments of the zoom lens applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0169] Embodiment 1

[0170] Continue to refer Figure 3-Figure 4 As shown, a zoom lens provided by the first embodiment of the present invention comprises a first fixed lens group G1 with positive focal power, a zoom lens group G2 with negative focal power, an aperture STO, a second fixed lens group G3 with positive focal power, a focus lens group G4 with positive focal power, and a third fixed lens group G5 with positive or negative focal power, which are arranged in sequence from the object plane to the image plane along the optical axis; the first fixed lens group G1, the second fixed lens group G2 and the third fixed lens group G5 are fixed, and the zoom lens group G3 and the focus lens group G4 move along the optical axis when zooming. A plane glass CG is also provided along the object plane to the image plane; the plane glass CG is located on the image plane IMA side of the seventeenth lens L17, and the plane glass CG can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the optical signal collected by the zoom lens into an electrical signal, thereby ensuring the imaging effect of the zoom lens.

[0171] In the zoom lens provided in this embodiment, the first fixed lens group G1, the variable power lens group G2, the second fixed lens group G3, the focus lens group G4 and the third fixed lens group G5 can be arranged in a lens barrel ( Figure 3 , Figure 4 The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in the lens barrel, and the variable power lens group G2 and the focus lens group G4 can move back and forth along the optical axis in the lens barrel. Through the joint movement of the variable power lens group G2 and the focus lens group G4, the focal length of the zoom lens can be continuously changed from short focus to long focus, ensuring that the zoom lens has high image quality at each focus position.

[0172] Among them, the direction from the object plane to the image plane along the optical axis is:

[0173] The first fixed lens group G1 includes a first lens L1 with negative power, a second lens L2 with positive power, and a third lens L3 with positive power. The first lens L1 and the second lens L2 are combined into a doublet lens group.

[0174] The zoom lens group G2 includes a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, and a seventh lens L7 with negative optical power. The fifth lens L5 and the sixth lens L6 are combined into a double cemented lens group.

[0175] The second fixed lens group G3 includes an eighth lens L8 with positive power, a ninth lens L9 with negative power, and a tenth lens L10 with positive power; the ninth lens L9 and the tenth lens L10 are combined into a doublet lens group.

[0176] The focusing lens group G4 includes an eleventh lens L11 with positive optical power, a twelfth lens L12 with negative optical power, a thirteenth lens L13 with positive optical power and a fourteenth lens L14 with negative optical power; the twelfth lens L12, the thirteenth lens L13 and the fourteenth lens L14 of the focusing lens group G4 are combined into a triplet lens group.

[0177] The third fixed lens group G5 includes a fifteenth lens L15 having positive power, a sixteenth lens L16 having negative power, and a seventeenth lens L17 having zero power.

[0178] The eighth lens L8 is a glass aspherical lens; the eleventh lens L11 is a glass aspherical lens; and the sixteenth lens L16 is a plastic aspherical lens.

[0179] For example, Table 1 details the specific optical and physical parameters of each lens in the zoom lens provided in Embodiment 1 of the present invention. The zoom lens in Table 1 corresponds to Figure 3 and Figure 4 Zoom lens shown.

[0180] Table 1 Design values ​​of optical physical parameters of zoom lens

[0181] Surface number S Surface type Curvature radius R thickness Materials (n.d.) Material (vd) 1 Spherical 174.823 0.800 1.81 25.46 2 Spherical 84.113 4.129 1.70 56.20 3 Spherical 676.620 0.080 4 Spherical 60.941 4.744 1.50 81.61 5 Spherical 289.577 Zoom interval 1 6 Spherical 79.930 0.650 1.72 37.99 7 Spherical 22.758 5.830 8 Spherical -87.698 0.800 1.49 70.44 9 Spherical 29.431 3.420 2.00 29.13 10 Spherical 145.663 3.360 11 Spherical -34.018 0.550 1.46 90.27 12 Spherical -291.069 Zoom interval 2 STO Spherical INF 0.100 14 Aspheric 35.101 3.332 1.50 81.58 15 Aspheric -74.602 1.778 16 Spherical -21.881 0.550 1.49 70.44 17 Spherical 18.625 7.723 1.44 95.10 18 Spherical -30.748 Zoom interval 3 19 Aspheric 20.998 9.572 1.55 71.68 20 Aspheric -42.774 0.080 21 Spherical 22.610 0.600 1.65 39.54 22 Spherical 10.582 7.407 1.50 81.61 23 Spherical -16.991 1.405 1.49 70.44 24 Spherical 13.029 Zoom interval 4 25 Spherical -268.436 1.413 1.69 54.54 26 Spherical -34.979 1.008 27 Aspheric -491.023 4.089 1.64 23.50 28 Aspheric 42.203 0.333 29 Spherical INF 1.000 1.52 58.57 30 Spherical INF 3.500 31 Spherical INF 1.000 1.52 58.57 32 Spherical INF 3.500 IMA Spherical INF -

[0182] Among them, the surface number S in Table 1 is numbered according to the surface order of each lens; "STO" represents the aperture of the zoom lens; IMA represents the image plane; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image plane, and a negative value represents that the surface is bent toward the object plane; "INF" represents 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 nd 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 vd represents the dispersion characteristics of the material between the current surface and the next surface to the light; the half-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0183] Furthermore, Table 2 shows the values ​​of zoom intervals of the zoom lens at the wide-angle end and the telephoto end in Table 1, in millimeters (mm).

[0184] Table 2 Design values ​​of variable pitch of zoom lens

[0185]

[0186] The zoom intervals in Table 2 are different interval values ​​of the zoom lens at the wide-angle end and the telephoto end.

[0187] Combination Figure 3 , Figure 4 As shown in Table 1 and Table 2, by adjusting the distances of the lens zoom interval 1, zoom interval 2, zoom interval 3, and zoom interval 4 at the wide-angle end and the telephoto end respectively, the zoom ratio of the zoom lens can be changed to have a larger zoom ratio.

[0188] In this embodiment, the aspherical lens of the zoom lens may satisfy the following formula:

[0189]

[0190] Where Z is the axial distance from the curved surface at a height r perpendicular to the optical axis 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, and a14 are the high-order aspheric coefficients of the corresponding aspheric surfaces of the fourth, sixth, eighth, tenth, twelfth, and fourteenth order, a i r i The combination becomes the high-order terms corresponding to the aspheric surface, i=4, 6, 8, 10, 12, 14.

[0191] Exemplarily, Table 3 describes in detail the aspheric coefficients of each lens in the first embodiment in a feasible implementation manner.

[0192] Table 3 Design values ​​of aspheric coefficients of each lens in zoom lens

[0193]

[0194] Among them, -2.665317365500E-05 means that the coefficient a4 of the surface number S11 is -2.665317365500*10 -5 , and so on.

[0195] As shown in Table 4, the zoom lens of the first embodiment achieves the following technical indicators:

[0196] Table 4 Parameters of the zoom lens of Example 1

[0197] Wide-angle end Telephoto end Image size(mm) Φ13.10 Φ13.10 Focal length(mm) 15.02 50.00 Wavelength(nm) 436-870 436-870 Total optical length (mm) 120.00 120.00

[0198] Figure 5 for Figure 3 The modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end is provided. Figure 5 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Figure 5 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. Among them, at 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the visible light band at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0199] The Modulation Transfer Function (MTF), also known as the spatial contrast transfer function and spatial frequency contrast sensitivity function, reflects the ability of the optical system to transfer the modulation of sinusoidal objects of various frequencies as a function of spatial frequency.

[0200] in, Figure 5 In the following figures, TS represents the meridian modulation transfer function curve and the arc-off modulation transfer function curve respectively.

[0201] Figure 6 for Figure 3The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end. Figure 6 , the vertical axis represents the modulation transfer function value; the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 6 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0202] Figure 7 for Figure 3 The modulation transfer function curve of the zoom lens in the wide-angle infrared band is provided. Figure 7 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Figure 7 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.5, indicating that the image quality of the zoom lens in the wide-angle infrared band is well controlled and meets the use requirements of 4k cameras.

[0203] Figure 8 for Figure 3 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the wide-angle end. Figure 8 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 8 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens in the wide-angle infrared band is well controlled and meets the use requirements of 4k cameras. The defocus value of the MTF peak at zero field of view is about 4μm compared to the visible light band, which is less than 5μm, and can meet the confocal requirements of the visible light band and the infrared band.

[0204] The MTF value does not exist in the form of a peak value, but refers to the value of each frequency point on the modulation transfer function (MTF) curve, which reflects the performance of the imaging system at different spatial frequencies. The MTF curve shows the relationship between contrast and image frequency. Usually, the MTF value is between 0 and 1, where 0 means no information is transmitted and 1 means all information is perfectly transmitted. In practical applications, the higher the MTF value, the better the performance of the imaging system at that frequency, and the better it can restore details.

[0205] MTF peak refers to the maximum value of the frequency at a point on the modulation transfer function (MTF) curve.

[0206] Fig. 9 for Figure 3 The provided modulation transfer function curve of the zoom lens at the wide-angle end and high temperature state. Fig. 9 , the vertical axis represents the modulation transfer function value, and the horizontal axis represents the spatial frequency. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig. 9 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.8 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the wide-angle end and high temperature state is well controlled, meeting the use requirements of 4k cameras.

[0207] Fig.10 for Figure 3 The provided zoom lens has a defocus modulation transfer function curve at high temperature at the wide angle end. Fig.10 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.10 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end and high temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 1μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the requirements of confocality at room and high temperature.

[0208] Fig.11 for Figure 3 The provided modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state. Fig.11 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.11 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the wide-angle end and low temperature state is well controlled, meeting the use requirements of 4k cameras.

[0209] Fig.12 for Figure 3 The provided zoom lens has a defocus modulation transfer function curve at the wide-angle end and low temperature. Fig.12 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.12It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end and low temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 2μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at both room and low temperature.

[0210] Fig.13 for Figure 4 The provided zoom lens has a modulation transfer function curve in the visible light band at the telephoto end. Fig.13 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.13 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the visible light band at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0211] Fig.14 for Figure 4 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the telephoto end. Fig.14 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.14 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0212] Fig.15 for Figure 4 The provided zoom lens has a modulation transfer function curve in the infrared band at the telephoto end. Fig.15 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.15 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.5, indicating that the image quality of the zoom lens in the infrared band at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0213] Fig.16 for Figure 4 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end. Fig.16, the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.16 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens in the infrared band at the telephoto end is well controlled, meeting the use requirements of 4k cameras. Among them, the defocus value of the MTF peak at zero field of view is about 4.9μm compared to the visible light band, which is less than 5μm, and can meet the requirements of confocality between the visible light band and the infrared band.

[0214] Fig.17 for Figure 4 The provided modulation transfer function curve of the zoom lens at the telephoto end and high temperature. Fig.16 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.17 It can be seen that the modulation transfer function values ​​of each frequency under the field of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.9 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the high temperature state at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0215] Fig.18 for Figure 4 The provided zoom lens has a defocus modulation transfer function curve at the telephoto end and high temperature. Fig.18 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.18 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end and high temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 0.5μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the requirements of confocality at both room and high temperature.

[0216] Fig.19 for Figure 4 The provided modulation transfer function curve of the zoom lens at the telephoto end under low temperature conditions. Fig.19 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.19It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.8 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the telephoto end and low temperature is well controlled, meeting the use requirements of 4k cameras.

[0217] Fig. 20 for Figure 4 The provided zoom lens has a defocus modulation transfer function curve at the telephoto end and low temperature. Fig. 20 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig. 20 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end and low temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 1μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the requirements of confocality at room temperature and low temperature.

[0218] Embodiment 2

[0219] Fig.21 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided in the second embodiment of the present invention. Fig. 22 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by the second embodiment of the present invention. Fig.21 and Fig. 22 A zoom lens provided in the second embodiment of the present invention comprises a first fixed lens group G1 with positive focal power, a zoom lens group G2 with negative focal power, an aperture STO, a second fixed lens group G3 with positive focal power, a focus lens group G4 with positive focal power, and a third fixed lens group G5 with positive or negative focal power, which are arranged in sequence from the object plane to the image plane along the optical axis; the first fixed lens group G1, the second fixed lens group G2 and the third fixed lens group G5 are fixed, and the zoom lens group G3 and the focus lens group G4 move along the optical axis when zooming. A plane glass CG is also provided along the object plane to the image plane; the plane glass CG is located on the image plane IMA side of the seventeenth lens L17, and the plane glass CG can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the optical signal collected by the zoom lens into an electrical signal, thereby ensuring the imaging effect of the zoom lens.

[0220] In the zoom lens provided in this embodiment, the first fixed lens group G1, the variable power lens group G2, the second fixed lens group G3, the focus lens group G4 and the third fixed lens group G5 can be arranged in a lens barrel ( Fig.21 , Fig. 22The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in the lens barrel, and the variable power lens group G2 and the focus lens group G4 can move back and forth along the optical axis in the lens barrel. Through the joint movement of the variable power lens group G2 and the focus lens group G4, the focal length of the zoom lens can be continuously changed from short focus to long focus, ensuring that the zoom lens has high image quality at each focus position.

[0221] Among them, the direction from the object plane to the image plane along the optical axis is:

[0222] The first fixed lens group G1 includes a first lens L1 with negative power, a second lens L2 with positive power, and a third lens L3 with positive power. The first lens L1 and the second lens L2 are combined into a doublet lens group.

[0223] The zoom lens group G2 includes a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, and a seventh lens L7 with negative optical power. The fifth lens L5 and the sixth lens L6 are combined into a double cemented lens group.

[0224] The second fixed lens group G3 includes an eighth lens L8 with positive power, a ninth lens L9 with negative power, and a tenth lens L10 with positive power; the ninth lens L9 and the tenth lens L10 are combined into a doublet lens group.

[0225] The focusing lens group G4 includes an eleventh lens L11 with positive optical power, a twelfth lens L12 with negative optical power, a thirteenth lens L13 with positive optical power and a fourteenth lens L14 with negative optical power; the twelfth lens L12, the thirteenth lens L13 and the fourteenth lens L14 of the focusing lens group G4 are combined into a triplet lens group.

[0226] The third fixed lens group G5 includes a fifteenth lens L15 having positive power, a sixteenth lens L16 having negative power, and a seventeenth lens L17 having zero power.

[0227] The eighth lens L8 is a glass aspherical lens; the eleventh lens L11 is a glass aspherical lens; and the sixteenth lens L16 is a plastic aspherical lens.

[0228] For example, Table 5 describes in detail the specific optical and physical parameters of each lens in the zoom lens provided in Example 2 of the present invention in a feasible implementation manner. Fig.21 and Fig. 22 Zoom lens shown.

[0229] Table 5 Design values ​​of optical physical parameters of zoom lens

[0230]

[0231]

[0232] Among them, the surface number S in Table 1 is numbered according to the order of the surfaces of each lens; "STO" represents the aperture STO of the zoom lens; IMA represents the image plane; the radius of curvature R 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" represents 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 nd 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 vd represents the dispersion characteristics of the material between the current surface and the next surface to the light; the half-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0233] Table 6 shows the values ​​of the zoom intervals of the zoom lens at the wide-angle end and the telephoto end in Table 5, in millimeters (mm).

[0234] Table 6 Design values ​​of variable pitch of zoom lens

[0235]

[0236]

[0237] The zoom intervals in Table 6 are different interval values ​​of the zoom lens at the wide-angle end and the telephoto end.

[0238] Combination Fig.21 and Fig. 22 As shown in Table 5 and Table 6, by adjusting the distances of the lens zoom interval 1, zoom interval 2, zoom interval 3, and zoom interval 4 at the wide-angle end and the telephoto end respectively, the zoom ratio of the zoom lens can be changed to have a larger zoom ratio.

[0239] In this embodiment, the aspherical lens of the zoom lens may satisfy the following formula:

[0240]

[0241] Where Z is the axial distance from the curved surface at a height r perpendicular to the optical axis 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, and a14 are the high-order aspheric coefficients of the corresponding aspheric surfaces of the fourth, sixth, eighth, tenth, twelfth, and fourteenth order, a i r i The combination becomes the high-order terms corresponding to the aspheric surface, i=4, 6, 8, 10, 12, 14.

[0242] Exemplarily, Table 7 describes in detail the aspheric coefficients of each lens in Example 2 of the present application in a feasible implementation manner.

[0243] Table 7 Design values ​​of aspheric coefficients of each lens in zoom lens

[0244]

[0245] Among them, -4.247193170006E-05 means that the coefficient a4 of the surface number S12 is -4.247193170006*10 -5 , and so on.

[0246] As shown in Table 8, the zoom lens of the second embodiment achieves the following technical indicators:

[0247] Table 8 Technical specifications of zoom lenses

[0248] Wide-angle end Telephoto end Image size(mm) Φmm)10 Φ0m)10 Focal length(mm) 15.01 50.00 Wavelength(nm) 436-870 436-870 Total optical length (mm) 120.00 120.00

[0249] Furthermore, the performance parameters of the zoom lens provided in Example 2 were tested, and the test results are as follows:

[0250] Fig.23 for Fig.21 The modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end is provided. Fig.23 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.23 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the visible light band at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0251] Fig.24 for Fig.21 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end. Fig.24 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.24 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0252] Fig.25 for Fig.21 The modulation transfer function curve of the zoom lens in the wide-angle infrared band is provided. Fig.25 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.25 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.5, indicating that the image quality of the zoom lens in the wide-angle infrared band is well controlled and meets the use requirements of 4k cameras.

[0253] Fig.26 for Fig.21 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the wide-angle end. Fig.26 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.26 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens in the wide-angle infrared band is well controlled, meeting the use requirements of 4k cameras. The zero field of view MTF peak has a defocus value of about 3μm compared to the visible light band, which is less than 5μm, and can meet the confocal requirements of the visible light band and the infrared band.

[0254] Fig. 27 for Fig.21 The provided modulation transfer function curve of the zoom lens at the wide-angle end and high temperature state. Fig. 27 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig. 27 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.9 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the wide-angle end and high temperature state is well controlled, meeting the use requirements of 4k cameras.

[0255] Fig.28 for Fig.21 The provided zoom lens has a defocus modulation transfer function curve at high temperature at the wide angle end. Fig.28 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.28It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end and high temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 1.5μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at both room and high temperature.

[0256] Fig.29 for Fig.21 The provided modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state. Fig.29 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.29 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the wide-angle end and low temperature state is well controlled, meeting the use requirements of 4k cameras.

[0257] Fig.30 for Fig.21 The provided zoom lens has a defocus modulation transfer function curve at the wide-angle end and low temperature. Fig.30 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.30 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end and low temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 2μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at room temperature and low temperature.

[0258] Fig.31 for Fig. 22 The provided zoom lens has a modulation transfer function curve in the visible light band at the telephoto end. Fig.31 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.31 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the visible light band at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0259] Fig.32 for Fig. 22 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the telephoto end. Fig.32 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.32 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0260] Fig.33 for Fig. 22 The provided zoom lens has a modulation transfer function curve in the infrared band at the telephoto end. Fig.33 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.33 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within 0.9 are all greater than 0.5, indicating that the image quality of the zoom lens in the infrared band at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0261] Fig.34 for Fig. 22 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end. Fig.34 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.34 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens in the infrared band at the telephoto end is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 4.9μm compared to the defocus value of the visible light band, which is less than 5μm, and can meet the requirements of confocality between the visible light band and the infrared band.

[0262] Fig.35 for Fig. 22 The provided modulation transfer function curve of the zoom lens at the telephoto end and high temperature. Fig.35 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.35 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.9 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the high temperature state at the telephoto end is well controlled, meeting the use requirements of 4k cameras.

[0263] Fig.36 for Fig. 22 The provided zoom lens has a defocus modulation transfer function curve at the telephoto end and high temperature. Fig.36 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.36 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end and high temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 1m less than 5μm compared to the defocus value of the visible light band at room temperature, which can meet the confocal requirements at both room and high temperature.

[0264] Fig.37 for Fig. 22 The provided modulation transfer function curve of the zoom lens at the telephoto end under low temperature conditions. Fig.37 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. From Figure 35, it can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. Among them, at 120 cycles / mm, the modulation transfer function values ​​within the 0.9 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the telephoto end and low temperature state is well controlled, meeting the use requirements of 4k cameras.

[0265] Fig.38 for Fig. 22 The provided zoom lens has a defocus modulation transfer function curve at the telephoto end and low temperature. Fig.38 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.38 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end and low temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 2.5μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at both room and low temperature.

[0266] Embodiment 3

[0267] Fig.39 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided in Embodiment 3 of the present invention. Fig.40 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by the third embodiment of the present invention. Fig.39 and Fig.40A zoom lens provided in the third embodiment of the present invention comprises a first fixed lens group G1 with positive focal power, a zoom lens group G2 with negative focal power, an aperture STO, a second fixed lens group G3 with positive focal power, a focus lens group G4 with positive focal power, and a third fixed lens group G5 with positive or negative focal power, which are arranged in sequence from the object plane to the image plane along the optical axis; the first fixed lens group G1, the second fixed lens group G2 and the third fixed lens group G5 are fixed, and the zoom lens group G3 and the focus lens group G4 move along the optical axis when zooming. A plane glass CG is also provided along the object plane to the image plane; the plane glass CG is located on the image plane IMA side of the seventeenth lens L17, and the plane glass CG can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the optical signal collected by the zoom lens into an electrical signal, thereby ensuring the imaging effect of the zoom lens.

[0268] In the zoom lens provided in this embodiment, the first fixed lens group G1, the variable power lens group G2, the second fixed lens group G3, the focus lens group G4 and the third fixed lens group G5 can be arranged in a lens barrel ( Fig.39 , Fig.40 The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in the lens barrel, and the variable power lens group G2 and the focus lens group G4 can move back and forth along the optical axis in the lens barrel. Through the joint movement of the variable power lens group G2 and the focus lens group G4, the focal length of the zoom lens can be continuously changed from short focus to long focus, ensuring that the zoom lens has high image quality at each focus position.

[0269] Among them, the direction from the object plane to the image plane along the optical axis is:

[0270] The first fixed lens group G1 includes a first lens L1 with negative power, a second lens L2 with positive power, and a third lens L3 with positive power. The first lens L1 and the second lens L2 are combined into a doublet lens group.

[0271] The zoom lens group G2 includes a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, and a seventh lens L7 with negative optical power. The fifth lens L5 and the sixth lens L6 are combined into a double cemented lens group.

[0272] The second fixed lens group G3 includes an eighth lens L8 with positive power, a ninth lens L9 with negative power, and a tenth lens L10 with positive power; the ninth lens L9 and the tenth lens L10 are combined into a doublet lens group.

[0273] The focusing lens group G4 includes an eleventh lens L11 with positive optical power, a twelfth lens L12 with negative optical power, a thirteenth lens L13 with positive optical power and a fourteenth lens L14 with negative optical power; the twelfth lens L12, the thirteenth lens L13 and the fourteenth lens L14 of the focusing lens group G4 are combined into a triplet lens group.

[0274] The third fixed lens group G5 includes a fifteenth lens L15 having positive power, a sixteenth lens L16 having negative power, and a seventeenth lens L17 having zero power.

[0275] The eighth lens L8 is a glass aspherical lens; the eleventh lens L11 is a glass aspherical lens; and the sixteenth lens L16 is a plastic aspherical lens.

[0276] For example, Table 9 describes in detail the specific optical and physical parameters of each lens in the zoom lens provided in Example 3 of the present invention in a feasible implementation manner. The zoom lens in Table 9 corresponds to Fig.39 and Fig.40 Zoom lens shown.

[0277] Table 9 Design values ​​of optical physical parameters of zoom lens

[0278]

[0279]

[0280] Among them, the surface number S in Table 1 is numbered according to the order of the surfaces of each lens; "STO" represents the aperture STO of the zoom lens; IMA represents the image plane; the radius of curvature R 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" represents 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 nd 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 vd represents the dispersion characteristics of the material between the current surface and the next surface to the light; the half-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0281] Table 10 shows the values ​​of the zoom intervals of the zoom lens at the wide-angle end and the telephoto end in Table 9, in millimeters (mm).

[0282] Table 10 Design values ​​of variable pitch of zoom lens

[0283] Wide-angle end Telephoto end Zoom interval 1 0.115 37.326 Zoom interval 2 37.357 0.147 Zoom interval 3 2.441 0.100 Zoom interval 4 2.164 4.505

[0284] Among them, the zoom intervals in Table 9 are the different interval values ​​of the zoom lens at the wide-angle end and the telephoto end.

[0285] Combination Fig.39 and Fig.40 As shown in Table 9 and Table 10, by adjusting the distances of the lens zoom interval 1, zoom interval 2, zoom interval 3, and zoom interval 4 at the wide-angle end and the telephoto end respectively, the zoom ratio of the zoom lens is changed to have a larger zoom ratio.

[0286] In this embodiment, the aspherical lens of the zoom lens may satisfy the following formula:

[0287]

[0288] Where Z is the axial distance from the curved surface at a height r perpendicular to the optical axis 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, and a14 are the high-order aspheric coefficients of the corresponding aspheric surfaces of the fourth, sixth, eighth, tenth, twelfth, and fourteenth order, a i r i The combination becomes the high-order terms corresponding to the aspheric surface, i=4, 6, 8, 10, 12, 14.

[0289] Exemplarily, Table 11 describes in detail the aspheric coefficients of each lens in Example 3 of the present application in a feasible implementation manner.

[0290] Table 11 Design values ​​of aspheric coefficients of each lens in zoom lens

[0291]

[0292]

[0293] Among them, -4.474201161E-05 means that the coefficient a4 of the surface number S11 is -4.474201161*10 -5 , and so on.

[0294] As shown in Table 12, the zoom lens of the third embodiment achieves the following technical indicators:

[0295] Table 12 Technical specifications of zoom lenses

[0296] Wide-angle end Telephoto end Image size(mm) Φmm) Φmm) Focal length(mm) 15.02 50.00 Wavelength(nm) 436-870 436-870 Total optical length (mm) 118.62 118.62

[0297] Furthermore, the performance parameters of the zoom lens provided in Example 3 were tested, and the test results are as follows:

[0298] Fig.41 for Fig.39 The modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end is provided. Fig.41 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.41 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the visible light band at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0299] Fig.42 for Fig.39 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end. Fig.42 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.42 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0300] Fig.43 for Fig.39 The modulation transfer function curve of the zoom lens in the wide-angle infrared band is provided. Fig.43 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.43 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the wide-angle infrared band is well controlled and meets the use requirements of 4k cameras.

[0301] Fig.44 for Fig.39 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the wide-angle end. Fig.44 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.44 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens in the wide-angle infrared band is well controlled, meeting the use requirements of 4k cameras. The zero field of view MTF peak has a defocus value of about 3μm compared to the visible light band, which is less than 5μm, and can meet the confocal requirements of the visible light band and the infrared band.

[0302] Fig.45 for Fig.39The provided modulation transfer function curve of the zoom lens at the wide-angle end and high temperature state. Fig.45 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.45 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.8 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the wide-angle end and high temperature state is well controlled, meeting the use requirements of 4k cameras.

[0303] Fig.46 for Fig.39 The provided zoom lens has a defocus modulation transfer function curve at high temperature at the wide angle end. Fig.46 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.46 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end and high temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 3μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at both room and high temperature.

[0304] Fig.47 for Fig.39 The provided modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state. Fig.47 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.47 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the wide-angle end and low temperature state is well controlled, meeting the use requirements of 4k cameras.

[0305] Fig.48 for Fig.39 The provided zoom lens has a defocus modulation transfer function curve at the wide-angle end and low temperature. Fig.48 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.48It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the wide-angle end and low temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 4μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at room temperature and low temperature.

[0306] Fig.49 for Fig.40 The provided zoom lens has a modulation transfer function curve in the visible light band at the telephoto end. Fig.49 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.49 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the visible light band at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0307] Fig.50 for Fig.40 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the telephoto end. Fig.50 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.50 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0308] Fig.51 for Fig.40 The provided zoom lens has a modulation transfer function curve in the infrared band at the telephoto end. Fig.51 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.51 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​in the entire field of view are all greater than 0.4, indicating that the image quality of the zoom lens in the infrared band at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0309] Fig.52 for Fig.40 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end. Fig.52, the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.52 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens in the infrared band at the telephoto end is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 4.5μm compared to the defocus value of the visible light band, which is less than 5μm, and can meet the confocal requirements of the visible light band and the infrared band.

[0310] Fig.53 for Fig.40 The provided modulation transfer function curve of the zoom lens at the telephoto end and high temperature. Fig.53 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.53 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.8 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the high temperature state at the telephoto end is well controlled, meeting the use requirements of 4k cameras.

[0311] Fig.54 for Fig.40 The provided zoom lens has a defocus modulation transfer function curve at the telephoto end and high temperature. Fig.54 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.54 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end and high temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 0.4μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at both room and high temperature.

[0312] Fig.55 for Fig.40 The provided modulation transfer function curve of the zoom lens at the telephoto end under low temperature conditions. Fig.55 , the vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 436nm to 656nm, and the main wavelength is 546nm. Fig.55It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​within the 0.8 field of view are all greater than 0.4, indicating that the image quality of the zoom lens at the telephoto end and low temperature is well controlled, meeting the use requirements of 4k cameras.

[0313] Fig.56 for Fig.40 The provided zoom lens has a defocus modulation transfer function curve at the telephoto end and low temperature. Fig.56 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Fig.56 It can be seen that the difference in the defocus value of the modulation transfer function peak under different fields of view is controlled within a reasonable range, indicating that the field curvature of the zoom lens at the telephoto end and low temperature is well controlled, meeting the use requirements of 4k cameras. The MTF peak value of 0 field of view is about 2μm compared to the defocus value of the visible light band at room temperature, which is less than 5μm, and can meet the confocal requirements at both room and low temperature.

[0314] In summary, in Embodiment 1, Embodiment 2 and Embodiment 3 of the present application, the optical physical parameters of the first lens to the sixteenth lens are as shown in Table 13.

[0315] Table 13 Design values ​​of optical physical parameters of zoom lens

[0316] Scope of protection Example 1 Example 2 Example 3 Lower limit Upper limit FNO 1.36 / 1.50 1.41 / 1.50 1.41 / 1.50 - 1.50 F1q / FW 7.63 6.71 6.65 6.65 7.63 F2q / FW -2.13 -1.93 -1.93 -2.13 -1.93 F3q / FW 6.22 6.27 6.31 6.21 6.31 F4q / FW 2.22 2.14 1.98 1.98 2.22 F5q / FW 42.62 49.67 72.90 42.62 72.90 S2 / S4 11.28 14.13 15.89 11.28 15.89 TTL / S4 32.90 45.35 50.60 32.90 50.60 F5-6 / F2q -5.87 -5.94 -4.88 -5.94 -4.88 F9-10 / F3q -1.21 -1.53 -1.18 -1.53 -1.18 F12-14 / F4q -1.56 -2.03 -2.13 -2.13 -1.56 Nd8 1.50 1.61 1.59 1.50 1.61 Nd11 1.55 1.44 1.50 1.44 1.55 Nd16 1.64 1.64 1.66 1.64 1.66 Vd8 81.58 57.74 66.85 57.74 81.58 Vd11 71.68 95.12 81.56 71.68 95.12 Vd16 23.50 23.50 20.38 20.38 23.50

[0317] 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 has been 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 invention comprises a first fixed lens group with positive optical power, a variable power lens group with negative optical power, an aperture, a second fixed lens group with positive optical power, a focusing lens group with positive optical power, and a third fixed lens group with positive optical power or negative optical power, which are arranged in sequence from the object plane to the image plane along the optical axis; the first fixed lens group, the second fixed lens group and the third fixed lens group are fixed, and the variable power lens group and the focusing lens group move along the optical axis direction when zooming; 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 variable power lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, a sixth lens with positive optical power and a seventh lens with negative optical power; The second fixed lens group includes an eighth lens with positive optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power; the second fixed lens group includes at least one aspherical lens; The focusing lens group includes an eleventh lens with positive optical power, a twelfth lens with negative optical power, a thirteenth lens with positive optical power and a fourteenth lens with negative optical power; the focusing lens group includes at least one aspherical lens; The third fixed lens group includes a fifteenth lens with positive optical power and a sixteenth lens with negative optical power; the third fixed lens group includes at least one aspherical lens.

2. The zoom lens according to claim 1, wherein: Along the direction from the object side to the image side of the optical axis, the surface of the lens close to the object plane is the object side surface, and the surface of the lens close to the image plane is the image side surface; In the first fixed lens group, the surface shape of the first lens is convex-concave; the object side surface of the second lens is convex; and the surface shape of the third lens is convex-concave; In the variable power lens group, the surface shape of the fourth lens is convex-concave, the surface shape of the fifth lens is concave-concave, the surface shape of the sixth lens is convex-concave, and the surface shape of the seventh lens is concave-convex; In the second fixed lens group, the surface shape of the eighth lens is convex-convex, the surface shape of the ninth lens is concave-concave, and the surface shape of the tenth lens is convex-convex; In the focusing lens group, the surface shape of the eleventh lens is convex-convex, the surface shape of the twelfth lens is convex-concave, the surface shape of the thirteenth lens is convex-convex, and the surface shape of the fourteenth lens is concave-concave; In the third fixed lens group, the image side surface of the fifteenth lens is convex, and the surface shape of the sixteenth lens is concave-concave.

3. The zoom lens according to claim 1, wherein: The zoom lens has a consistent aperture position relative to the image plane position at different focal lengths, and the aperture diameter is the same at different focal lengths, satisfying: FNO≤1.50; Wherein, FNO is the aperture size of the zoom lens at different focal lengths.

4. The zoom lens according to claim 1, wherein: The eighth lens is a glass aspheric lens; the eleventh lens is a glass aspheric lens; the sixteenth lens is a plastic aspheric lens, and the third fixed lens group further includes a seventeenth lens with zero optical power.

5. The zoom lens according to claim 1, wherein: 6.65≤F1 / FW≤-7.63;-2.13≤F2 / FW≤-1.93;6.21≤F3 / FW≤6.31; 1.98≤F4 / FW≤2.22; 42.62≤F5 / FW≤72.90; Among them, F1, F2, F3, F4, and F5 are the focal lengths of the first fixed lens group, the variable power lens group, the second fixed lens group, the focusing lens group, and the third fixed lens group respectively; and FW is the focal length of the wide-angle end of the zoom lens.

6. The zoom lens according to claim 1, wherein: 11.28≤S2 / S4≤15.89; Among them, S2 is the maximum distance that the zoom lens group moves along the optical axis direction, and S4 is the maximum distance that the focus lens group moves along the optical axis direction.

7. The zoom lens according to claim 1, wherein: 1.50≤nd8≤1.61;57.74≤vd8≤81.58; 1.44≤nd11≤1.55;71.68≤vd11≤95.12; 1.64≤nd16≤1.66; 20.38≤vd16≤23.5; Among them, nd8, nd11, and nd16 represent the refractive indices of the eighth lens, the eleventh lens, and the sixteenth lens respectively, and vd8, vd11, and vd16 represent the Abbe numbers of the eighth lens, the eleventh lens, and the sixteenth lens respectively.

8. The zoom lens according to claim 1, wherein: The first lens and the second lens are combined into a doublet lens group.

9. The zoom lens according to claim 1, wherein: The fifth lens and the sixth lens of the variable power lens group are combined into a double cemented lens group, which satisfies: -5.94≤F5-6 / F2q≤-4.88; Among them, F5-6 represents the focal length of the double-cemented lens group, and F2q represents the focal length of the second fixed lens group.

10. The zoom lens according to claim 1, wherein: The ninth lens and the tenth lens of the second fixed lens group are combined into a double cemented lens group, which satisfies: -1.53≤F9-10 / F3q≤-1.18; Among them, F9-10 represents the focal length of the double-cemented lens group, and F3q represents the focal length of the second fixed lens group.

11. The zoom lens according to claim 1, wherein: The twelfth lens, the thirteenth lens and the fourteenth lens of the focusing lens group are combined into a triplet lens group, satisfying: -2.13≤F12-14 / F4q≤-1.56; Among them, F12-14 represents the focal length of the triplet lens group, and F4q represents the focal length of the focusing lens group.

12. The zoom lens according to claim 1, wherein: 32.90≤TTL / S4≤50.60; Wherein, TTL represents the total length of the zoom lens, and S4 represents the maximum distance that the focus lens group moves along the optical axis direction.

Images