A zoom lens

Abstract

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

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) lenses are specifically designed for image sensors. Currently, most ITS lenses commonly used on the market are fixed-focus lenses with low image quality and poor tolerance to harsh environments. Faced with increasingly complex operating environments, zoom lenses are becoming increasingly popular in the ITS field. However, the variety of zoom lenses available for ITS applications is extremely limited, and they suffer from issues such as low image quality, a narrow focal length range, and a limited temperature range, making them difficult to use in practice. Therefore, it is crucial to develop a zoom lens with a large aperture, high resolution, a wide temperature range, and a long focal length that meets ITS requirements. Summary of the Invention

[0003] The present invention provides a zoom lens that can achieve large aperture, high and low temperature confocality, and 4K clear imaging on a 1 / 1.2″ target surface and in the 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 stop, a second fixed lens group with positive optical power, a focus lens group with positive optical power, and a third fixed lens group with positive or negative optical power, arranged in sequence along an optical axis from an object plane to an image plane; 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 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 zoom lens assembly includes a fourth lens having negative optical power, a fifth lens having negative optical power, a sixth lens having positive optical power, and a seventh lens having negative optical power;

[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 of the first lens is convex-concave; the object side surface of the second lens is convex; and the surface of the third lens is convex-concave;

[0012] In the zoom 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 maintains a consistent diaphragm position relative to the image plane position at different focal lengths, and the diaphragm diameter is 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 zoom 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 zoom lens at the wide-angle end.

[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, and S4 is the maximum distance that the focus lens group moves along the optical axis.

[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] Wherein, 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 magnification lens group are combined into a doublet lens group, which satisfies:

[0029] -5.94≤F5-6 / F2q≤-4.88;

[0030] Wherein, 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 doublet lens group, which satisfies:

[0032] -1.53≤F9-10 / F3q≤-1.18;

[0033] Wherein, 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] Wherein, 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.

[0038] The zoom lens provided by an embodiment of the present invention includes a first fixed lens group, a variator lens group, an aperture, a second fixed lens group, a focus lens group, and a third fixed lens group, arranged in sequence along the optical axis from the object plane to the image plane. The optical powers are respectively positive, negative, positive, positive, positive, positive, or negative. The first fixed lens group consists of three lenses, and the optical powers are respectively negative, positive, and positive. The variator lens group consists of four lenses, and the optical powers are respectively negative, negative, positive, and negative. The second fixed lens group consists of three lenses, and the optical powers are respectively positive, negative, and positive. The focus lens group consists of four lenses, and the optical powers are respectively positive, negative, positive, and negative. The third fixed lens group consists 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. This zoom lens can achieve the 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 structural diagram of a zoom lens at the wide-angle end provided by the present invention;

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

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

[0042] Figure 4 A schematic structural diagram 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 Provides the defocus modulation transfer function curve of the zoom lens 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 Provides the defocus modulation transfer function curve of the zoom lens in the wide-angle infrared band;

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

[0048] Figure 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] Figure 11 for Figure 3 The provided modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state;

[0050] Figure 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] Figure 13 for Figure 4 The provided zoom lens provides a modulation transfer function curve for the visible light band at the telephoto end.

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

[0053] Figure 15 for Figure 4 The provided zoom lens provides a modulation transfer function curve for the infrared band at the telephoto end.

[0054] Figure 16 for Figure 4 Provide the defocus modulation transfer function curve of the zoom lens in the infrared band at the telephoto end;

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

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

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

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

[0059] Figure 21 A schematic structural diagram of the zoom lens at the wide-angle end provided in the second embodiment of the present invention;

[0060] Figure 22 A schematic structural diagram of a zoom lens at the telephoto end provided by the second embodiment of the present invention;

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

[0062] Figure 24 for Figure 21 Provides the defocus modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end;

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

[0064] Figure 26 for Figure 21 Provides the defocus modulation transfer function curve of the zoom lens in the wide-angle infrared band;

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

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

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

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

[0069] Figure 31 for Figure 22 The provided zoom lens provides a modulation transfer function curve for the visible light band at the telephoto end.

[0070] Figure 32 for Figure 22 Provide the defocus modulation transfer function curve of the zoom lens in the visible light band at the telephoto end;

[0071] Figure 33 for Figure 22 The provided zoom lens provides a modulation transfer function curve for the infrared band at the telephoto end.

[0072] Figure 34 for Figure 22 Provide the defocus modulation transfer function curve of the zoom lens in the infrared band at the telephoto end;

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

[0074] Figure 36 for Figure 22 Provides the defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature;

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

[0076] Figure 38 for Figure 22 Provides the defocus modulation transfer function curve of the zoom lens at the telephoto end at low temperature;

[0077] Figure 39 A schematic structural diagram of the zoom lens at the wide-angle end provided in the third embodiment of the present invention;

[0078] Figure 40 A schematic diagram of the structure of the zoom lens at the telephoto end provided by the third embodiment of the present invention;

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

[0080] Figure 42 for Figure 39 Provides the defocus modulation transfer function curve of the zoom lens in the visible light band at the wide-angle end;

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

[0082] Figure 44 for Figure 39 Provides the defocus modulation transfer function curve of the zoom lens in the wide-angle infrared band;

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

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

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

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

[0087] Figure 49 for Figure 40 The provided zoom lens provides a modulation transfer function curve for the visible light band at the telephoto end.

[0088] Figure 50 for Figure 40 Provide the defocus modulation transfer function curve of the zoom lens in the visible light band at the telephoto end;

[0089] Figure 51 for Figure 40 The provided zoom lens provides a modulation transfer function curve for the infrared band at the telephoto end.

[0090] Figure 52 for Figure 40 Provide the defocus modulation transfer function curve of the zoom lens in the infrared band at the telephoto end;

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

[0092] Figure 54 for Figure 40 Provides the defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature;

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

[0094] Figure 56 for Figure 40 Provided is the defocus modulation transfer function curve of the zoom lens at the telephoto end and low temperature. DETAILED DESCRIPTION

[0095] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0096] Figure 1 This is a schematic structural diagram 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, an embodiment of the present invention provides a zoom lens including 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 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 during zooming.

[0097] The direction from the object plane to the image plane along the optical axis:

[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 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.

[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 having positive refractive power and a sixteenth lens L16 having negative refractive 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 (not shown in the figure). The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in position 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 stationary 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 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 can adjust the distance between the lens and the object or the imaging plane to ensure 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 in the process of zooming by moving the zoom lens group G2 and the focus lens group G4, when the focal length is shortest, the zoom lens is at the wide-angle end, and when the focal length is longest, the zoom lens is at the telephoto end. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical 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 of aspherical surfaces are not represented according to actual conditions.

[0106] Furthermore, the focal length 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 inverse of the focal length, and it characterizes the ability of the zoom lens to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length 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, reference Figure 1 and Figure 2The first fixed lens group G1 is composed of at least three lenses arranged in sequence along the optical axis from the object plane to the image plane. 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 along the optical axis from the object plane to the image plane. Among them, the fourth lens L4 has a negative optical power, the fifth lens L5 has a negative optical power, the sixth lens L6 has a positive optical power, and the seventh lens L7 has a negative optical power.

[0110] The second fixed lens group G3 consists of at least three lenses arranged in sequence along the optical axis from the object plane to the image plane. The eighth lens L8 has positive power, the ninth lens L9 has negative power, and the tenth lens L10 has positive power. The second fixed lens group G3 also includes at least one aspherical lens. When light passes through the aperture STO, the use of an aspherical lens effectively corrects aberrations, preventing aberrations from accumulating at the rear end of the lens, making it difficult to retract the lens, and thus effectively improving image quality.

[0111] Focusing lens group G4 consists of at least four lenses arranged in sequence along the optical axis from the object plane to the image plane. Among them, the eleventh lens L11 has a positive optical power, the twelfth lens L12 has a negative optical power, the thirteenth lens L13 has a positive optical power, and the fourteenth lens L14 has a negative optical power. 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 along the optical axis from the object plane to the image plane. The fifteenth lens L15 has a positive optical power, the sixteenth lens L16 has a negative optical power, 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 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 surface, namely, the fourth, sixth, eighth, tenth, twelfth, and fourteenth order. 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 stop and a field stop. The aperture stop refers to the stop that limits the light beam the most, and the field stop refers to the stop that limits the field of view (size) the most.

[0117] Reference Figure 1 and Figure 2 The front end of the iris STO uses a first fixed lens group G1 with positive focal length and a zoom lens group G2 with negative focal length. This ensures a larger light aperture after light passes through, increasing the aperture number of the zoom lens to meet the needs of different conditions. The rear end of the iris STO uses a second fixed lens group G3 with positive focal length, a focusing lens group G4 with positive focal length, and a third fixed lens group G5 with either positive or negative focal length to correct aberrations at the rear end of the lens. Together with the lens group at the front end of the iris STO, this stabilizes the imaging quality of the zoom lens.

[0118] Specifically, placing the aperture stop STO between the negative-power seventh lens element L7 and the positive-power eighth lens element L8 can regulate the propagation direction of the light beam emitted by the seventh lens element L7 to the incident surface of the eighth lens element 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 focusing 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 distributes 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 zoom movement of the zoom lens group G2, thereby effectively achieving aberration balance in each focal length and ensuring the clarity of the image under different focal length states.

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

[0121] Based on the above embodiments, Figure 3-Figure 4 The eighth lens L8 is a glass aspheric lens; the eleventh lens L11 is a glass aspheric lens; the sixteenth lens L16 is a plastic aspheric 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 to glass aspherical lenses helps to reduce the number of lenses, thereby reducing the lens volume.

[0123] Plastic lenses are much cheaper than glass lenses. Sixteenth lens L16 can be a plastic aspheric lens, significantly reducing the cost of zoom lenses. The third fixed lens group G5 can also include a seventeenth lens L17, which serves as the final lens element. This lens has zero optical power and is also known as a flat glass lens. This lens effectively protects sixteenth lens L16, preventing it from being exposed to wear and dirt outside the lens.

[0124] At the same time, glass and plastic can also play a complementary role in balancing high and low temperatures, making the zoom lens have stable high and low temperature performance. This helps to improve the environmental adaptability of the zoom lens and is conducive to achieving the 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, and this is not limited here. The material of the plastic aspheric 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. This embodiment of the present invention does not elaborate on this and does not limit this.

[0126] Based on the above embodiments, Figures 1-4 , 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 surface, and the surface of the lens close to the image plane is the image side surface.

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

[0128] The concave lens has a diverging effect on the transmitted light, while 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 can be achieved at various focal lengths of the zoom lens.

[0129] Based on the above embodiments, Figures 1-4 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 doublet. This effectively reduces the air gap between the first lens L1 and the second lens L2, thereby shortening the overall length of the zoom lens. The doublet formed by cementing the first lens L1 and the second lens L2 is a convex cemented negative lens. This cemented lens group facilitates the smooth collection of object-side light into the imaging system, significantly correcting higher-order aberrations. Furthermore, this shape allows for better collection of light at a wide field of view, ensuring wide-angle imaging requirements.

[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, Figures 1-4 The variator lens group G2 includes at least one cemented lens, such as the fifth lens L5 and the sixth lens L6 are combined into a double cemented lens group, and the focal length of the double cemented lens group and the focal length of the variator lens group G2 satisfy the following relationship: -5.94≤F5-6 / F2q≤-4.88.

[0132] Wherein, F5-6 represents the focal length of the doublet lens group consisting 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-level 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, Figures 1-4 The ninth lens L9 and the tenth lens L10 of the second fixed lens group G3 are combined into a doublet lens group. The focal length of the doublet 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 the doublet lens group consisting 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, light can pass smoothly through the middle end of the lens. In addition, before the light enters the zoom lens group G4, the use of cemented lenses can reduce chromatic aberration and aberration generated at the front end, further improving image quality.

[0138] Based on the above embodiments, Figures 1-4 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. The focal length of the triplet lens group and the focal length of the focusing lens group G4 must satisfy the following relationship: -2.13≤F12-14 / F4q≤-1.56.

[0139] Wherein, 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 changing 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 realizing the focus of the zoom lens at the entire focal length.

[0141] At the same time, the cemented 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 performance such as distortion, reduce light loss caused by reflection between lenses, increase illumination, thereby improving image quality and enhancing the clarity of lens imaging. In addition, the cemented 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 sensitivity of lens units to tolerances such as tilt / eccentricity caused by the assembly process.

[0142] Based on the above embodiments, Figures 1-4 , the position of the aperture STO relative to the image plane of the zoom lens remains consistent at different focal lengths, and the aperture diameter is the same at different focal lengths, and at the same time, it meets the following requirements: FNO ≤ 1.50. Here, FNO is the aperture size of the zoom lens at different focal lengths.

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

[0144] Based on the above embodiments, Figures 1-4 , 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 power, allowing light to pass through the lens more smoothly, and to a large extent correcting the impact of high-level aberrations on imaging quality.

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

[0150] Wherein, 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 entire 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, Figures 1-4 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] Here, 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, to ensure stable imaging across the entire focal length of a zoom lens, it is typically necessary to individually achromatize and control aberrations in the fixed lens group to prevent excessive accumulation of chromatic aberrations and aberrations after entering the moving lens group, making them difficult to control and affecting image quality. In this application, the eighth lens L8 is paired with the aforementioned lens materials to control the chromatic aberrations and aberrations entering the focusing lens group G4 within a reasonable range, preventing them from being excessively amplified during the movement of the zoom lens group G3, making them difficult to correct later.

[0158] The use of the same materials as the eleventh lens L11 in the focusing lens group G4 further reduces the effects of chromatic aberration and image aberration in the zoom lens group G3. The use of the same materials in the sixteenth lens L16 corrects the chromatic aberration and image aberration of the entire lens, keeping light within a reasonable range before it enters the image plane.

[0159] In addition, aspherical lenses have a good ability to control the high-order 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-order aberrations when light enters the image plane, so that the image quality can be further improved to meet the needs of 4K imaging.

[0160] Furthermore, glass lenses are not sensitive to temperature. The use of glass aspherical lenses in the eighth and eleventh lenses, L8 and L11, ensures consistent performance across different temperatures, resulting in stable high and low-temperature performance. Furthermore, the use of a plastic aspherical lens in the sixteenth lens, L16, effectively compensates for the expansion and contraction of the lens frame at high and low temperatures, enhancing the zoom lens's environmental adaptability.

[0161] The introduction of glass aspherical lenses has also largely corrected the chromatic aberration and high-order aberrations of the lens. 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, Figures 1-4 , 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 with a certain thickness is provided between the sixteenth lens L16 and the image plane IMA; Figure 3-Figure 4 A flat glass L18 of a certain thickness is provided between the seventeenth lens L17 and the image plane IMA. While providing protection, it can also filter out unwanted stray light, thereby improving the imaging quality of the zoom lens. For example, the flat glass L18 can filter out infrared light during the day to improve the imaging quality of the zoom lens.

[0166] In summary, the zoom lens provided by the embodiments of the present invention, through the rational combination of optical power, refractive index, and materials of the five lens groups, can effectively achieve aberration balance at each focal length, ensuring image clarity at different focal lengths. It can achieve the requirements of large aperture, high and low temperature confocality, and 4K clear imaging on a target area as large as 1 / 1.2" and in the 436nm-870nm band.

[0167] The zoom lens provided in the embodiments of this application, when used in an ITS lens, offers high resolution, low distortion, and high contrast, providing clear, accurate, and high-quality images. Its design takes into account optical properties, mechanical structure, and electronic interfaces, effectively adapting 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] Example 1

[0170] Continue to refer Figure 3-Figure 4 As shown, a zoom lens provided by Embodiment 1 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 focus lens group G4 with positive optical focal length, and a third fixed lens group G5 with positive or negative optical focal length, 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, while the variator lens group G3 and the focus lens group G4 move along the optical axis during zooming. A flat glass CG is also provided along the length from the object plane to the image plane. The flat glass CG is located on the image plane IMA side of the seventeenth lens L17. The flat 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 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 one 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 position within the lens barrel, while the variator lens group G2 and the focus lens group G4 can reciprocate along the optical axis within the lens barrel. The combined movement of the variator lens group G2 and the focus lens group G4 allows the focal length of the zoom lens to continuously change from short focus to long focus, ensuring high image quality at all focal positions.

[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 optical power, a second lens L2 with positive optical power, and a third lens L3 with positive optical 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 form a doublet lens group.

[0175] 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 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 cemented lens triplet.

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

[0182] The surface number S in Table 1 is numbered according to the order of the lens surfaces; "STO" represents the aperture of a zoom lens; IMA represents the image plane; the radius of curvature R represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane; "INF" indicates that the surface is flat and has an infinite radius of curvature; the thickness represents the central axial distance from the current surface to the next surface; the refractive index nd represents the light-bending ability of the material between the current and next surfaces; a blank space represents the current position as air with a refractive index of 1. The Abbe number vd represents the light-dispersion properties of the material between the current and next surfaces; and the half-aperture represents half the lens aperture. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less chromatic dispersion of the medium, the larger the Abbe number.

[0183] Furthermore, Table 2 shows the values ​​of the 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] Combine 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 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 surface, namely, the fourth, sixth, eighth, tenth, twelfth, and fourteenth order. i r i The combination becomes the high-order terms corresponding to the aspheric surface, i = 4, 6, 8, 10, 12, 14.

[0191] For example, 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 provided zoom lens has a modulation transfer function curve in the visible light band at the wide-angle end. 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 5 It can be seen that the modulation transfer function values ​​at various frequencies under different fields of view are all controlled within a reasonable range. Specifically, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the zoom lens has good image quality in the visible light band at the wide-angle end, meeting the requirements of 4K cameras.

[0199] The Modulation Transfer Function (MTF), also known as the spatial contrast transfer function or spatial frequency contrast sensitivity function, reflects the optical system's ability to transfer sinusoidal modulations 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, meeting the requirements of 4K cameras.

[0202] Figure 7 for Figure 3 The provided zoom lens has a modulation transfer function curve in the wide-angle infrared band. 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 ​​at various frequencies under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.5, indicating that the zoom lens has good image quality control in the wide-angle infrared band, meeting the 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 As can be seen, the difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, indicating that the zoom lens's field curvature in the wide-angle infrared band is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 4μm compared to the visible light band, less than 5μm, meeting the requirement for confocality between the visible and infrared bands.

[0204] The MTF value is not expressed as a peak value, but rather as the values ​​at various frequency points on the modulation transfer function (MTF) curve. These values ​​reflect the performance of the imaging system at different spatial frequencies. The MTF curve shows the relationship between contrast and image frequency. Typically, the MTF value ranges from 0 to 1, where 0 indicates no information transfer and 1 indicates perfect information transfer. In practical applications, a higher MTF value indicates better performance of the imaging system at that frequency, enabling better detail reproduction.

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

[0206] Figure 9 for Figure 3 The provided modulation transfer function curve of the zoom lens at the wide-angle end and high temperature state. Figure 9 , the vertical axis represents the modulation transfer function value, and the horizontal axis represents the spatial frequency. The simulated visible light band range is 436nm to 656nm, and the main wavelength is 546nm. Figure 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. Among them, 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 this zoom lens is well controlled under high temperature conditions at the wide-angle end, meeting the requirements of 4K camera use.

[0207] Figure 10 for Figure 3 The provided zoom lens defocus modulation transfer function curve at high temperature at wide angle end. Figure 10 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 10 As can be seen, the difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, demonstrating that the zoom lens's field curvature at the wide-angle end and high temperature is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 1μm at visible light at room temperature, less than 5μm, meeting the requirements for confocality at both room and high temperatures.

[0208] Figure 11 for Figure 3 The provided modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens is well controlled at low temperatures at the wide-angle end, meeting the requirements of 4K cameras.

[0209] Figure 12 for Figure 3 The provided zoom lens defocus modulation transfer function curve at the wide-angle end and low temperature state. Figure 12 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 12As can be seen, the difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, demonstrating that the zoom lens's field curvature at the wide-angle end and low temperatures is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 2μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements for confocality at both room and low temperatures.

[0210] Figure 13 for Figure 4 The provided zoom lens has a modulation transfer function curve in the visible light band at the telephoto end. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens in the visible light band at the telephoto end is well controlled, meeting the requirements of 4K cameras.

[0211] Figure 14 for Figure 4 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the telephoto end. Figure 14 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 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, meeting the requirements of 4K cameras.

[0212] Figure 15 for Figure 4 The provided zoom lens has a modulation transfer function curve in the infrared band at the telephoto end. Figure 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. Figure 15 It can be seen that the modulation transfer function values ​​at various frequencies under different fields of view are all controlled within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.5, indicating that the image quality of this zoom lens in the infrared band at the telephoto end is well controlled, meeting the requirements of 4K cameras.

[0213] Figure 16 for Figure 4 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end. Figure 16, the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 16 As can be seen, the difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, demonstrating that the zoom lens's field curvature in the infrared band at the telephoto end is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 4.9μm compared to the visible light band, less than 5μm, meeting the requirement for confocality between the visible and infrared bands.

[0214] Figure 17 for Figure 4 The provided modulation transfer function curve of the zoom lens at the telephoto end and high temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 17 It can be seen that the modulation transfer function values ​​at all frequencies within 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 this zoom lens is well controlled at high temperatures at the telephoto end, meeting the requirements of 4K cameras.

[0215] Figure 18 for Figure 4 The provided defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature state. Figure 18 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 18 As can be seen, the difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, demonstrating that the zoom lens's field curvature at the telephoto end and high temperature is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 0.5μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements for confocality at both room and high temperatures.

[0216] Figure 19 for Figure 4 The provided modulation transfer function curve of the zoom lens at the telephoto end at low temperature. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, 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 this zoom lens is well controlled at low temperatures at the telephoto end, meeting the requirements of 4K camera use.

[0217] Figure 20 for Figure 4 The provided defocus modulation transfer function curve of the zoom lens at the telephoto end at low temperature. Figure 20 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 20 As can be seen, the difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, demonstrating that the zoom lens's field curvature at the telephoto end is well controlled at low temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 1μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements for confocality at both room and low temperatures.

[0218] Example 2

[0219] Figure 21 This is a schematic structural diagram of the zoom lens at the wide-angle end provided by the second embodiment of the present invention. Figure 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. Figure 21 and Figure 22 A zoom lens provided in a second 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 focus lens group G4 with positive optical focal length, and a third fixed lens group G5 with positive 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, while the variator lens group G3 and the focus lens group G4 move along the optical axis during zooming. A flat glass CG is also provided along the distance from the object plane to the image plane. The flat glass CG is located on the image plane IMA side of the seventeenth lens L17. The flat 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 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 one lens barrel ( Figure 21 、 Figure 22The first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are fixed in position within the lens barrel, while the variator lens group G2 and the focus lens group G4 can reciprocate along the optical axis within the lens barrel. The combined movement of the variator lens group G2 and the focus lens group G4 allows the focal length of the zoom lens to continuously change from short focus to long focus, ensuring high image quality at all focal positions.

[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 optical power, a second lens L2 with positive optical power, and a third lens L3 with positive optical 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 form a doublet lens group.

[0224] 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 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 cemented lens triplet.

[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 by Example 2 of the present invention in a feasible implementation manner. The zoom lens in Table 5 corresponds to Figure 21 and Figure 22 Zoom lens shown.

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

[0230]

[0231]

[0232] The surface number S in Table 1 is numbered according to the order of the lens surfaces; "STO" represents the aperture stop STO of the zoom lens; IMA represents the image plane; the radius of curvature R represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane; "INF" indicates that the surface is flat 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 light-bending ability of the material between the current and next surfaces; a blank space represents the current position as air with a refractive index of 1. The Abbe number vd represents the light-dispersion properties of the material between the current and next surfaces; and the half-aperture represents half the lens aperture. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less chromatic dispersion of the medium, 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 the different interval values ​​of the zoom lens at the wide-angle end and the telephoto end.

[0238] Combine Figure 21 and Figure 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 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 surface, namely, the fourth, sixth, eighth, tenth, twelfth, and fourteenth order. i r i The combination becomes the high-order terms corresponding to the aspheric surface, i = 4, 6, 8, 10, 12, 14.

[0242] For example, 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 the 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] Figure 23 for Figure 21 The provided zoom lens has a modulation transfer function curve in the visible light band at the wide-angle end. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 23 The modulation transfer function values ​​for each frequency at different fields of view are all within a reasonable range. At 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that this zoom lens has excellent image quality control in the visible light band at the wide-angle end, meeting the requirements of 4K cameras.

[0251] Figure 24 for Figure 21 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end. Figure 24 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 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, meeting the requirements of 4K camera use.

[0252] Figure 25 for Figure 21 The provided zoom lens has a modulation transfer function curve in the wide-angle infrared band. Figure 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. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.5, indicating that the image quality of this zoom lens in the wide-angle infrared band is well controlled, meeting the requirements of 4K cameras.

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

[0254] Figure 27 for Figure 21 The provided modulation transfer function curve of the zoom lens at the wide-angle end and high temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. 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 this zoom lens is well controlled under high temperature conditions at the wide-angle end, meeting the requirements of 4K camera use.

[0255] Figure 28 for Figure 21 The provided zoom lens defocus modulation transfer function curve at high temperature at wide angle end. Figure 28 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 28It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the zoom lens's field curvature is well controlled at the wide-angle end and at high temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 1.5μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements for confocality at both room and high temperatures.

[0256] Figure 29 for Figure 21 The provided modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens is well controlled at the wide-angle end and low temperature state, meeting the requirements of 4K camera use.

[0257] Figure 30 for Figure 21 The provided zoom lens defocus modulation transfer function curve at the wide-angle end and low temperature state. Figure 30 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 30 It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the zoom lens's field curvature at the wide-angle end is well controlled at low temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 2μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements for confocality at both room and low temperatures.

[0258] Figure 31 for Figure 22 The provided zoom lens has a modulation transfer function curve in the visible light band at the telephoto end. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens in the visible light band at the telephoto end is well controlled, meeting the requirements of 4K cameras.

[0259] Figure 32 for Figure 22 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the telephoto end. Figure 32 , the vertical axis represents the modulation transfer function value, the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 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, meeting the requirements of 4K camera use.

[0260] Figure 33 for Figure 22 The provided zoom lens has a modulation transfer function curve in the infrared band at the telephoto end. Figure 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. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​within 0.9 are all greater than 0.5, indicating that the image quality of this zoom lens in the infrared band at the telephoto end is well controlled, meeting the requirements of 4K camera use.

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

[0262] Figure 35 for Figure 22 The provided modulation transfer function curve of the zoom lens at the telephoto end and high temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. 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 this zoom lens is well controlled at high temperatures at the telephoto end, meeting the requirements of 4K cameras.

[0263] Figure 36 for Figure 22 The provided defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature state. Figure 36 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 36 It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the zoom lens's field curvature at the telephoto end is well controlled at high temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is less than 5μm, compared to approximately 1m at room temperature in the visible light band, meeting the requirements for confocality at both room and high temperatures.

[0264] Figure 37 for Figure 22 The provided modulation transfer function curve of the zoom lens at the telephoto end at low temperature. Figure 37 The vertical axis represents the modulation transfer function (MTF) value (unit: none); the horizontal axis represents the spatial frequency (unit: cyc / mm). The simulated visible light wavelength range is 436nm to 656nm, with a dominant wavelength of 546nm. Figure 35 shows that the MTF values ​​for each frequency at different fields of view are all within reasonable ranges. At 120 cycles / mm, the MTF values ​​within a 0.9 field of view are all greater than 0.4, indicating that this zoom lens maintains excellent image quality at the telephoto end at low temperatures, meeting the requirements of 4K cameras.

[0265] Figure 38 for Figure 22 The provided defocus modulation transfer function curve of the zoom lens at the telephoto end at low temperature. Figure 38 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 38 It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the zoom lens's field curvature at the telephoto end is well controlled at low temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 2.5μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements for confocality at both room and low temperatures.

[0266] Example 3

[0267] Figure 39 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided by the third embodiment of the present invention. Figure 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. Figure 39 and Figure 40A zoom lens provided in a third embodiment of the present invention includes a first fixed lens group G1 with positive focal length, a variator lens group G2 with negative focal length, an aperture STO, a second fixed lens group G3 with positive focal length, a focus lens group G4 with positive focal length, and a third fixed lens group G5 with positive or negative focal length, 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, while the variator lens group G3 and the focus lens group G4 move along the optical axis during zooming. A flat glass CG is also provided along the length from the object plane to the image plane. The flat glass CG is located on the image plane IMA side of the seventeenth lens L17. The flat 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 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 one lens barrel ( Figure 39 、 Figure 40 The first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are fixed in position within the lens barrel, while the variator lens group G2 and the focus lens group G4 can reciprocate along the optical axis within the lens barrel. The combined movement of the variator lens group G2 and the focus lens group G4 allows the focal length of the zoom lens to continuously change from short focus to long focus, ensuring high image quality at all focal positions.

[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 optical power, a second lens L2 with positive optical power, and a third lens L3 with positive optical 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 form a doublet lens group.

[0272] 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 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 cemented lens triplet.

[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 Figure 39 and Figure 40 Zoom lens shown.

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

[0278]

[0279]

[0280] The surface number S in Table 1 is numbered according to the order of the lens surfaces; "STO" represents the aperture stop STO of the zoom lens; IMA represents the image plane; the radius of curvature R represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane; "INF" indicates that the surface is flat 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 light-bending ability of the material between the current and next surfaces; a blank space represents the current position as air with a refractive index of 1. The Abbe number vd represents the light-dispersion properties of the material between the current and next surfaces; and the half-aperture represents half the lens aperture. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less chromatic dispersion of the medium, the larger the Abbe number.

[0281] Table 10 shows the values ​​of the zoom intervals of the zoom lenses 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] 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] Combine Figure 39 and Figure 40 As shown in Tables 9 and 10, by adjusting the distances of 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 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 surface, namely, the fourth, sixth, eighth, tenth, twelfth, and fourteenth order. i r i The combination becomes the high-order terms corresponding to the aspheric surface, i = 4, 6, 8, 10, 12, 14.

[0289] For example, 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) technology Φmm) technology 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] Figure 41 for Figure 39 The provided zoom lens has a modulation transfer function curve in the visible light band at the wide-angle end. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens in the visible light band at the wide-angle end is well controlled, meeting the requirements of 4K cameras.

[0299] Figure 42 for Figure 39 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the wide-angle end. Figure 42 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 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, meeting the requirements of 4K camera use.

[0300] Figure 43 for Figure 39 The provided zoom lens has a modulation transfer function curve in the wide-angle infrared band. Figure 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. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​throughout the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens in the wide-angle infrared band is well controlled, meeting the requirements of 4K cameras.

[0301] Figure 44 for Figure 39 The provided zoom lens has a defocus modulation transfer function curve in the wide-angle infrared band. Figure 44 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 44 It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the zoom lens's field curvature in the wide-angle infrared band is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 3μm compared to the visible light band, less than 5μm, meeting the requirement for confocality between the visible and infrared bands.

[0302] Figure 45 for Figure 39The provided modulation transfer function curve of the zoom lens at the wide-angle end and high temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, 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 this zoom lens is well controlled under high temperature conditions at the wide-angle end, meeting the requirements of 4K camera use.

[0303] Figure 46 for Figure 39 The provided zoom lens defocus modulation transfer function curve at high temperature at wide angle end. Figure 46 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 46 The difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, demonstrating that the zoom lens's field curvature at wide-angle and high-temperature conditions is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 3μm at visible light at room temperature, less than 5μm, meeting the requirements for confocality at both room and high temperatures.

[0304] Figure 47 for Figure 39 The provided modulation transfer function curve of the zoom lens at the wide-angle end and low temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens is well controlled at the wide-angle end and low temperature state, meeting the requirements of 4K camera use.

[0305] Figure 48 for Figure 39 The provided zoom lens defocus modulation transfer function curve at the wide-angle end and low temperature state. Figure 48 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 48It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the zoom lens's field curvature at the wide-angle end is well controlled at low temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 4μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements of confocality at both room and low temperatures.

[0306] Figure 49 for Figure 40 The provided zoom lens has a modulation transfer function curve in the visible light band at the telephoto end. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens in the visible light band at the telephoto end is well controlled, meeting the requirements of 4K cameras.

[0307] Figure 50 for Figure 40 The provided zoom lens has a defocus modulation transfer function curve in the visible light band at the telephoto end. Figure 50 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 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, meeting the requirements of 4K camera use.

[0308] Figure 51 for Figure 40 The provided zoom lens has a modulation transfer function curve in the infrared band at the telephoto end. Figure 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. Figure 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. Among them, at 120 cycles / mm, the modulation transfer function values ​​across the entire field of view are all greater than 0.4, indicating that the image quality of this zoom lens in the infrared band at the telephoto end is well controlled, meeting the requirements of 4K cameras.

[0309] Figure 52 for Figure 40 The provided zoom lens has a defocus modulation transfer function curve in the infrared band at the telephoto end. Figure 52, the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 52 It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the zoom lens's field curvature in the infrared band at the telephoto end is well controlled, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 4.5μm compared to the visible light band, less than 5μm, meeting the requirement for confocality between the visible and infrared bands.

[0310] Figure 53 for Figure 40 The provided modulation transfer function curve of the zoom lens at the telephoto end and high temperature state. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, 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 this zoom lens is well controlled at high temperatures at the telephoto end, meeting the requirements of 4K cameras.

[0311] Figure 54 for Figure 40 The provided defocus modulation transfer function curve of the zoom lens at the telephoto end and high temperature state. Figure 54 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 54 It can be seen that the difference in defocus between the modulation transfer function peaks at different fields of view is well within a reasonable range, indicating that the field curvature of this zoom lens is well controlled at the telephoto end and at high temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 0.4μm compared to the visible light band at room temperature, less than 5μm, meeting the requirements of confocality at both room and high temperatures.

[0312] Figure 55 for Figure 40 The provided modulation transfer function curve of the zoom lens at the telephoto end at low temperature. Figure 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 range is 436nm~656nm, and the main wavelength is 546nm. Figure 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. Among them, 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 this zoom lens is well controlled at the telephoto end and low temperature state, meeting the requirements of 4K camera use.

[0313] Figure 56 for Figure 40 The provided defocus modulation transfer function curve of the zoom lens at the telephoto end at low temperature. Figure 56 , the vertical axis represents the modulation transfer function value, and the vertical axis represents the defocus amount, the unit is millimeter (mm). Figure 56 The difference in defocus between the modulation transfer function peaks at different fields of view is well within reasonable limits, demonstrating that the zoom lens's field curvature at the telephoto end is well controlled at low temperatures, meeting the requirements of 4K cameras. The zero-field MTF peak defocus is approximately 2μm at visible light at room temperature, less than 5μm, meeting the requirements for confocality at both room and low temperatures.

[0314] In summary, in Example 1, Example 2, and Example 3 of the present application, the optical and physical parameters of the first to sixteenth lenses are 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 employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A zoom lens, characterized in that: The optical lens comprises 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, which are arranged in sequence along the optical axis from the object plane to the image plane; 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 during 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, which are arranged in sequence from the object plane to the image plane along the optical axis; The zoom 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, which are arranged in sequence from the object plane to the image plane along the optical axis; 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, which are arranged in sequence along the optical axis from the object plane to the image plane; the second fixed lens group includes an aspheric 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 an aspherical lens; The third fixed lens group includes a fifteenth lens having positive optical power and a sixteenth lens having negative optical power; the third fixed lens group includes an aspherical lens; The number of lenses with optical power in the zoom lens is 16; 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 zoom 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 zoom lens at the wide-angle end.

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 of the first lens is convex-concave; the object side surface of the second lens is convex; and the surface of the third lens is convex-concave; In the zoom lens group, the surface of the fourth lens is convex-concave, the surface of the fifth lens is concave-concave, the surface of the sixth lens is convex-concave, and the object side surface of the seventh lens is concave; 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 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 flat glass.

4. 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, and S4 is the maximum distance that the focus lens group moves along the optical axis.

5. 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; Wherein, 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.

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

7. The zoom lens according to claim 1, wherein: The fifth lens and the sixth lens of the variable magnification lens group are combined into a doublet lens group, which satisfies: -5.94≤F5-6 / F2≤-4.88; Wherein, F5-6 represents the focal length of the double-cemented lens group.

8. 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 doublet lens group, which satisfies: -1.53≤F9-10 / F3≤-1.18; Wherein, F9-10 represents the focal length of the double-cemented lens group.

9. 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 the following: -2.13≤F12-14 / F4≤-1.56; Wherein, F12-14 represents the focal length of the triplet lens group.

10. 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.

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