Zoom lens and imaging device

Abstract

The present invention discloses a zoom lens and an imaging device. The zoom lens comprises a lens barrel and a lens group. The lens group comprises a first lens group with positive focal power, a second lens group with negative focal power, a third lens group with positive focal power, a fourth lens group with positive focal power and a fifth lens group which are arranged in sequence from the object side to the image side. The first lens group and the fifth lens group are fixedly mounted on the lens barrel, and the second lens group, the third lens group and the fourth lens group are movably mounted on the lens barrel along the optical axis. In the technical solution of the present invention, through the reasonable arrangement of five lens groups and the conditional restriction of the focal length of the zoom lens at the wide-angle end and the ratio of the focal lengths of each lens group, the zoom lens has wide-angle and small distortion effects while reducing the aperture size.

Description

Technical Field

[0001] The present invention relates to the technical field of optical system design, and in particular to a zoom lens and an imaging device applied to an indoor monitoring system or a video system. Background Art

[0002] The mainstream high-quality zoom surveillance lenses on the market require the lens to have a large enough field of view to obtain a wider field of view, and the lens is often designed to have a wide-angle effect. The design concept of the lens with a wide-angle effect is to sacrifice the distortion of the lens, and to collect as much light as possible with great distortion. Therefore, the edge area of ​​the picture is severely compressed due to the huge deformation, and the image information around the picture cannot be distinguished, resulting in poor imaging quality. In indoor monitoring, in order to ensure that a large range of the photographed area can be clearly monitored, there are higher requirements for the distortion of the picture. Existing surveillance lenses generally use many glass aspherical lenses to reduce the impact of distortion, but the manufacturing cost is high. The zoom lenses currently used in indoor monitoring systems or video systems are beginning to develop in the direction of home use and low cost. Therefore, surveillance lenses with high manufacturing costs can no longer meet market demand. Summary of the invention

[0003] The main purpose of the present invention is to provide a zoom lens, aiming to improve the technical problem that wide angle and small distortion cannot coexist in the lens of the prior art.

[0004] To achieve the above object, the present invention provides a zoom lens, wherein the zoom lens has an object side and an image side that are arranged opposite to each other along an optical axis direction, and the zoom lens comprises:

[0005] a lens barrel; and,

[0006] A lens group, the lens group comprises a first lens group with positive focal power, a second lens group with negative focal power, an aperture, a third lens group with positive focal power, a fourth lens group with positive focal power, a fifth lens group and a photosensitive chip, which are sequentially arranged from the object side to the image side, wherein the first lens group and the fifth lens group are fixedly mounted on the lens barrel, the second lens group, the third lens group and the fourth lens group are movably mounted on the lens barrel along the optical axis, the second lens group and the third lens group move in coordination along the optical axis to enable the zoom lens to zoom, and the fourth lens group moves along the optical axis to enable the zoom lens to focus;

[0007] Among them, the zoom lens satisfies the following conditions: 0.046 < fw / f1 < 0.068, and -0.478 < fw / f2 < -0.319, and 0.089 < fw / f3 < 0.134, and 0.113 < fw / f4 < 0.169, and -0.262 < fw / f5 < 0.262;

[0008] Among them, fw is the focal length of the zoom lens at the wide-angle end, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, and f5 is the focal length of the fifth lens group.

[0009] Optionally, the first lens group includes a first lens with a negative optical power, a second lens with a positive optical power, and a third lens with a positive optical power, which are arranged in sequence from the object side to the image side;

[0010] Among them, the first lens group, the first lens, the second lens, and the third lens satisfy the following conditions: -0.783 < f1 / f11 < -0.522, and 0.665 < f1 / f12 < 0.997, and 0.716 < f1 / f13 < 1.074;

[0011] Among them, f1 is the focal length of the first lens group, f11 is the focal length of the first lens, f12 is the focal length of the second lens, and f13 is the focal length of the third lens.

[0012] Optionally, the second lens group includes a fourth lens with a negative optical power, a fifth lens, a sixth lens with a negative optical power, a seventh lens with a negative optical power, and an eighth lens with a positive optical power, which are arranged in sequence from the object side to the image side, and the fifth lens is a plastic aspherical lens;

[0013] Among them, the second lens group, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy the following conditions: 0.669 < f2 / f21 < 1.004, and -0.089 < f2 / f22 < 0.089, and 0.251 < f2 / f23 < 0.586, and 0.236 < f2 / f24 < 0.55, and -0.628 < f2 / f25 < -0.338;

[0014] Among them, f2 is the focal length of the second lens group, f21 is the focal length of the fourth lens, f22 is the focal length of the fifth lens, f23 is the focal length of the sixth lens, f24 is the focal length of the seventh lens, and f25 is the focal length of the eighth lens.

[0015] Optionally, the third lens group includes a ninth lens with a positive refractive power, a tenth lens with a positive refractive power, and an eleventh lens with a negative refractive power, which are arranged in sequence from the object side to the image side, and the ninth lens is a glass aspherical lens;

[0016] Wherein, the third lens group, the ninth lens, the tenth lens, and the eleventh lens satisfy the following conditions: 1.114 < f3 / f31 < 2.069, and 0.569 < f3 / f32 < 1.056, and -1.99 < f3 / f33 < -1.071;

[0017] Wherein, f3 is the focal length of the third lens group, f31 is the focal length of the ninth lens, f32 is the focal length of the tenth lens, and f33 is the focal length of the eleventh lens.

[0018] Optionally, the fourth lens group includes a twelfth lens with a positive refractive power, a thirteenth lens with a positive refractive power, a fourteenth lens with a positive refractive power, a fifteenth lens with a negative refractive power, and a sixteenth lens, which are arranged in sequence from the object side to the image side, and the sixteenth lens is a plastic aspherical lens;

[0019] Wherein, the fourth lens group, the twelfth lens, the thirteenth lens, the fourteenth lens, the fifteenth lens, and the sixteenth lens satisfy the following conditions: 0.653 < f4 / f41 < 1.088, and 0.897 < f4 / f42 < 1.666, and 1.122 < f4 / f43 < 1.869, and -4.222 < f4 / f44 < -2.533, and -0.84 < f4 / f45 < 0.252;

[0020] Wherein, f4 is the focal length of the fourth lens group, f41 is the focal length of the twelfth lens, f42 is the focal length of the thirteenth lens, f43 is the focal length of the fourteenth lens, f44 is the focal length of the fifteenth lens, and f45 is the focal length of the sixteenth lens.

[0021] Optionally, the fifth lens group includes a seventeenth lens, and the seventeenth lens is a plastic aspherical lens.

[0022] Optionally, the zoom lens satisfies the following conditions:

[0023] Wherein, is the effective aperture of the first lens, and TTL is the overall optical length of the zoom lens.

[0024] Optionally, the zoom lens satisfies the following conditions: 0.271 < ΔZ1 W-T / TTL < 0.366;

[0025] Among them, ΔZ W-T is the relative displacement of the second lens group when the zoom lens is at the wide-angle end position and when the zoom lens is at the telephoto end position, and TTL is the total optical length of the zoom lens.

[0026] Optionally, the zoom lens satisfies the following condition: 0.026<ΔZ2 W-T / TTL<0.062;

[0027] Among them, ΔZ2 W-T is the relative displacement of the third lens group when the zoom lens is at the wide-angle end position and when the zoom lens is at the telephoto end position, and TTL is the total optical length of the zoom lens.

[0028] An imaging device comprises the zoom lens described in the above technical solution.

[0029] In the technical solution provided by the present invention, the first lens group and the fifth lens group are fixedly mounted on the lens barrel, and the second lens group, the third lens group, and the fourth lens group are movably mounted on the lens barrel along the optical axis, wherein the second lens group and the third lens group are used for zooming, and the fourth lens group is used for focusing, and the second lens group and the third lens group move cooperatively along the optical axis so that the zoom lens can zoom from the wide-angle end to the telephoto end, and the fourth lens group is driven by an external force to move along the optical axis in conjunction with the second lens group and the third lens group. The mobile focus corresponding to the position of the lens group, the imaging wavelength, and the imaging object distance enables the zoom lens to maintain clear imaging on the imaging surface during the zooming process, and the first lens group has positive focal power, the second lens group has negative focal power, the third lens group has positive focal power, the fourth lens group has positive focal power, and the fifth lens group has positive focal power or negative. Through the reasonable arrangement of the five lens groups and the conditional restrictions on the focal length of the zoom lens at the wide-angle end and the focal length ratio of each lens group, the zoom lens has wide-angle, small distortion, and large magnification effects while reducing the aperture size. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0031] Figure 1A schematic structural diagram of the first embodiment of the zoom lens provided by the present invention when it is at the wide-angle end;

[0032] Figure 2 for Figure 1 Schematic diagram of the structure of the zoom lens when it is at an intermediate magnification;

[0033] Figure 3 for Figure 1 Schematic diagram of the structure of the zoom lens when it is at the telephoto end;

[0034] Figure 4 for Figure 2 Aberration diagram of the zoom lens at the wide-angle end;

[0035] Figure 5 for Figure 2 Field curvature diagram when the zoom lens is at the wide-angle end;

[0036] Figure 6 for Figure 2 Distortion diagram of the zoom lens at the wide-angle end;

[0037] Figure 7 for Figure 1 Spherical aberration diagram of the zoom lens at intermediate magnifications;

[0038] Figure 8 for Figure 1 Field curvature diagram for a zoom lens at intermediate magnifications;

[0039] Fig. 9 for Figure 1 Distortion diagram of the zoom lens at intermediate magnifications;

[0040] Fig.10 for Figure 3 Aberration diagram of the zoom lens at the telephoto end;

[0041] Fig.11 for Figure 3 Field curvature diagram when the zoom lens is at the telephoto end;

[0042] Fig.12 for Figure 3 Distortion diagram of the zoom lens at the telephoto end;

[0043] Fig.13 A schematic structural diagram of the second embodiment of the zoom lens provided by the present invention at the wide-angle end;

[0044] Fig.14 for Fig.13 Schematic diagram of the structure of the zoom lens when it is at an intermediate magnification;

[0045] Fig.15 for Fig.13Schematic diagram of the structure of the zoom lens when it is at the telephoto end;

[0046] Fig.16 for Fig.14 Aberration diagram of the zoom lens at the wide-angle end;

[0047] Fig.17 for Fig.14 Field curvature diagram when the zoom lens is at the wide-angle end;

[0048] Fig.18 for Fig.14 Distortion diagram of the zoom lens at the wide-angle end;

[0049] Fig.19 for Fig.13 Aberration diagram of the zoom lens at intermediate magnifications;

[0050] Fig. 20 for Fig.13 Field curvature diagram for a zoom lens at intermediate magnifications;

[0051] Fig.21 for Fig.13 Distortion diagram of the zoom lens at intermediate magnifications;

[0052] Fig. 22 for Fig.15 Aberration diagram of the zoom lens at the telephoto end;

[0053] Fig.23 for Fig.15 Field curvature diagram when the zoom lens is at the telephoto end;

[0054] Fig.24 for Fig.15 Distortion diagram of the zoom lens at the telephoto end.

[0055] Description of Figure Numbers:

[0056]

[0057]

[0058] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] It should be noted that if a directional indication is involved in the embodiment of the present invention, the directional indication is only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0061] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0062] The present invention provides a zoom lens, which aims to improve the technical problem that wide angle and small distortion cannot coexist in the prior art. Figures 1 to 24 , the accompanying drawings show a specific embodiment of the zoom lens.

[0063] First embodiment

[0064] Figures 1 to 12 This is the first embodiment of the zoom lens provided by the present invention.

[0065] Please refer to Figures 1 to 3, the zoom lens has an object side and an image side that are oppositely arranged along the optical axis direction. The zoom lens includes a lens barrel (not shown in the figure) and a lens group. The lens barrel extends along the optical axis direction. The lens group includes a first lens group 1 with a positive optical power, a second lens group 2 with a negative optical power, a diaphragm 6, a third lens group 3 with a positive optical power, a fourth lens group 4 with a positive optical power, a fifth lens group 5, and an image sensor chip 8, which are arranged in sequence from the object side to the image side. Moreover, the optical power of the fifth lens group can be positive or negative. Among them, the first lens group 1, the fifth lens group 5, and the image sensor chip 8 are fixedly installed on the lens barrel. The second lens group 2, the third lens group 3, and the fourth lens group 4 are movably installed on the lens barrel along the optical axis direction. And the second lens group 2 and the third lens group 3 move cooperatively along the optical axis direction to zoom the zoom lens. The fourth lens group 4 moves along the optical axis direction to focus the zoom lens. When the second lens group 2 and the third lens group 3 are driven by an external force to move along the optical axis toward the image side direction, the zoom lens zooms from the wide-angle end to the telephoto end. And the fourth lens group 4 is driven by an external force to move along the optical axis in correspondence with the positions of the second lens group 2 and the third lens group 3, the imaging wavelength, and the imaging object distance for focusing, so that the imaging surface of the zoom lens remains in clear focus during the zooming process.

[0066] Moreover, the zoom lens satisfies the following conditions: 0.046 < fw / f1 < 0.068, and -0.478 < fw / f2 < -0.319, and 0.089 < fw / f3 < 0.134, and 0.113 < fw / f4 < 0.169, and -0.262 < fw / f5 < 0.262; where fw is the focal length of the zoom lens at the wide-angle end, f1 is the focal length of the first lens group 1, f2 is the focal length of the second lens group 2, f3 is the focal length of the third lens group 3, f4 is the focal length of the fourth lens group 4, and f5 is the focal length of the fifth lens group 5.

[0067] In this embodiment, the ratios of the focal length of the zoom lens at the wide-angle end to the focal lengths of the respective lens groups are as follows: fw / f1 = 0.055; fw / f2 = -0.374; fw / f3 = 0.106; fw / f4 = 0.127; fw / f5 = 0.215.

[0068] It should be noted that the second lens group 2, the third lens group 3, and the fourth lens group 4 can all be driven by an external force to move along the optical axis direction. Among them, the external force drive can be a drive motor drive or manual adjustment by hand, which is not limited here.

[0069] In the technical solution provided by the present invention, the first lens group 1 and the fifth lens group 5 are fixedly installed on the lens barrel, and the second lens group 2, the third lens group 3, and the fourth lens group 4 are movably installed on the lens barrel along the optical axis direction. Among them, the second lens group 2 and the third lens group 3 are used for zooming, and the fourth lens group 4 is used for focusing. When the second lens group 2 and the third lens group 3 move cooperatively along the optical axis direction to zoom the zoom lens from the wide-angle end to the telephoto end, and the fourth lens group 4 is driven by an external force to move along the optical axis for focusing corresponding to the positions of the second lens group 2 and the third lens group 3, the imaging wavelength, and the imaging object distance, so that the imaging surface of the zoom lens remains clear during the zooming process. Moreover, the first lens group 1 has a positive optical power, the second lens group 2 has a negative optical power, the third lens group 3 has a positive optical power, the fourth lens group 4 has a positive optical power, and the optical power of the fifth lens group 5 can be positive or negative. Through the reasonable setting of the five lens groups and the conditional limitation of the ratio of the focal length of the wide-angle end of the zoom lens to the focal lengths of each lens group, the zoom lens has a wide angle and a small distortion effect while reducing the aperture size.

[0070] Specifically, the first lens group 1 includes a first lens 11 with a negative optical power, a second lens 12 with a positive optical power, and a third lens 13 with a positive optical power, which are arranged in sequence from the object side to the image side. Moreover, the first lens group 1, the first lens 11, the second lens 12, and the third lens 13 satisfy the following conditions: -0.783 < f1 / f11 < -0.522, and 0.665 < 1 / f12 < 0.997, and 0.716 < f1 / f13 < 1.074; where f1 is the focal length of the first lens group 1, f11 is the focal length of the first lens 11, f12 is the focal length of the second lens 12, and f13 is the focal length of the third lens 13.

[0071] More specifically, in this embodiment, the first lens 11 is a convex-concave spherical lens with a negative optical power, that is, the object side surface of the first lens 11 is a convex surface and the image side surface is a concave surface. The second lens 12 is a convex-concave spherical lens with a positive optical power, and the third lens 13 is a convex-concave spherical lens with a positive optical power. Moreover, the ratio of the focal length of the first lens group to the focal lengths of each lens is specifically as follows: f1 / f11 = -0.589; f1 / f12 = 0.763; f1 / f13 = 0.857;

[0072] Further, the first lens 11 and the second lens 12 are glued together to form a first glued lens with a positive optical power, and the following conditions are satisfied: 0.124 < f1 / f1112 < 0.23; where f1 is the focal length of the first lens group 1, and f1112 is the focal length of the first glued lens.

[0073] In this embodiment, the ratio of the first lens group to the first glued lens is specifically: f1 / f1112 = 0.164.

[0074] Furthermore, each lens in the first lens group 1 respectively satisfies the following conditions: 1.7 < ND11 < 2.1, and 1.4 < ND12 < 1.7, and 1.6 < ND13 < 2, and 10 < VD11 < 40, and 60 < VD12 < 100, and 30 < VD13 < 65; where ND11 is the refractive index of the first lens 11, ND12 is the refractive index of the second lens 12, ND13 is the refractive index of the third lens 13, VD11 is the Abbe number of the first lens 11, VD12 is the Abbe number of the second lens 12, VD13 is the Abbe number of the third lens 13. In this embodiment, the specific refractive indices and Abbe numbers of the above lenses are shown in Table 1 below.

[0075] Specifically, the second lens group 2 includes a fourth lens 21 with a negative optical power, a fifth lens 22, a sixth lens 23 with a negative optical power, a seventh lens 24 with a negative optical power, and an eighth lens 25 with a positive optical power, which are arranged in sequence from the object side to the image side. The fifth lens is a plastic aspherical lens, and the optical power of the fifth lens can be positive or negative; and, the second lens group 2 and the fourth lens 21, the fifth lens 22, the sixth lens 23, the seventh lens 24, the eighth lens 25 satisfy the following conditions: 0.669 < f2 / f21 < 1.004, and -0.089 < f2 / f22 < 0.089, and 0.251 < f2 / f23 < 0.586, and 0.236 < f2 / f24 < 0.55, and -0.628 < f2 / f25 < -0.338; where f2 is the focal length of the second lens group 2, f21 is the focal length of the fourth lens 21, f22 is the focal length of the fifth lens 22, f23 is the focal length of the sixth lens 23, f24 is the focal length of the seventh lens 24, and f25 is the focal length of the eighth lens 25.

[0076] More specifically, in this embodiment, the fifth lens 22 has a positive optical power, the fourth lens 21 is a convex-concave spherical lens with a negative optical power, the fifth lens 22 is a convex-concave aspherical lens, the sixth lens 23 is a double-concave spherical lens with a negative optical power, the seventh lens 24 is a concave-convex spherical lens with a negative optical power, and the eighth lens 25 is a convex lens with a positive optical power, that is, the object side of the eighth lens is a plane and the image side is a convex surface; the focal length ratios of the second lens group to each of the lenses therein are as follows: f2 / f21 = 0.823; f2 / f22 = 2.2E-4; f2 / f23 = 0.414; f2 / f24 = 0.29; f2 / f25 = -0.433. It should be noted that E-4 represents 10 to the power of -4.

[0077] Specifically, the third lens group 3 includes a ninth lens 31 with a positive optical power, a tenth lens 32 with a positive optical power, and an eleventh lens 33 with a negative optical power, which are arranged in sequence from the object side to the image side. Moreover, the ninth lens is a glass aspherical lens; and the third lens group 3, the ninth lens 31, the tenth lens 32, and the eleventh lens 33 satisfy the following conditions: 1.114 < f3 / f31 < 2.069, and 0.569 < f3 / f32 < 1.056, and -1.99 < f3 / f33 < -1.071; where f3 is the focal length of the third lens group 3, f31 is the focal length of the ninth lens 31, f32 is the focal length of the tenth lens 32, and f33 is the focal length of the eleventh lens 33.

[0078] More specifically, in this embodiment, the ninth lens 31 is a double-convex aspherical lens with a positive optical power, the tenth lens 32 is a double-convex spherical lens with a positive optical power, the eleventh lens 33 is a convex-concave spherical lens with a negative optical power, and the focal length ratios of the third lens group 3 to each of the lenses therein are as follows: f3 / f31 = 1.435; f3 / f32 = 0.787; f3 / f33 = -1.428.

[0079] Specifically, the fourth lens group 4 includes a twelfth lens 41 with positive refractive power, a thirteenth lens 42 with positive refractive power, a fourteenth lens 43 with positive refractive power, a fifteenth lens 44 with negative refractive power, and a sixteenth lens 45, which are arranged in sequence from the object side to the image side. Moreover, the sixteenth lens is a plastic aspherical lens, and the refractive power of the sixteenth lens can be positive or negative. The fourth lens group 4, the twelfth lens 41, the thirteenth lens 42, the fourteenth lens 43, the fifteenth lens 44, and the sixteenth lens 45 satisfy the following conditions: 0.653 < f4 / f41 < 1.088, 0.897 < f4 / f42 < 1.666, 1.122 < f4 / f43 < 1.869, -4.222 < f4 / f44 < -2.533, and -0.84 < f4 / f45 < 0.252. Herein, f4 is the focal length of the fourth lens group 4, f41 is the focal length of the twelfth lens 42, f42 is the focal length of the thirteenth lens 42, f43 is the focal length of the fourteenth lens 43, f44 is the focal length of the fifteenth lens 44, and f45 is the focal length of the sixteenth lens 45.

[0080] More specifically, in this embodiment, the twelfth lens 41 is a convex-concave spherical lens with positive refractive power, the thirteenth lens 42 is a biconvex spherical lens with positive refractive power, the fourteenth lens 43 is a biconvex spherical lens with positive refractive power, the fifteenth lens 44 is a biconcave spherical lens with negative refractive power, the sixteenth lens 45 is a convex-concave spherical lens with negative refractive power, and the ratio of the focal lengths of the fourth lens group 4 to each of the lenses is as follows: f4 / f41 = 0.858; f4 / f42 = 1.249; f4 / f43 = 1.531; f4 / f44 = -3.409; f4 / f45 = -0.68.

[0081] Further, the fourteenth lens 43 and the fifteenth lens 44 are glued together to form a second cemented lens, and the second cemented lens has negative refractive power and satisfies the following condition: -2 < f4 / f4344 < -1.1. Herein, f4 is the focal length of the fourth lens group 4, and f4344 is the focal length of the second cemented lens.

[0082] In this embodiment, the specific ratio of the fourth lens group to the second cemented lens is: f4 / f4344 = -1.549.

[0083] Specifically, in this embodiment, the fifth lens group 5 includes a seventeenth lens 51, and the seventeenth lens 51 is a plastic aspherical lens, and the refractive power of the seventeenth lens 51 can be positive or negative.

[0084] More specifically, in this embodiment, the seventeenth lens is a biconvex lens with a positive optical power.

[0085] It can be understood that the surface of the photosensitive chip 8 facing the object side is the imaging surface.

[0086] Specifically, the zoom lens further includes a diaphragm 6, and the diaphragm 6 is located between the second lens group 2 and the third lens group 3; that is, the diaphragm 6 is located between the eighth lens 25 and the ninth lens 31. In this embodiment, the diaphragm 6 is an adjustable diaphragm, and the adjustable diaphragm can perform corresponding aperture scaling measures according to the change of the ambient light intensity. Moreover, the zoom lens satisfies the following condition: 0.318 < L / TTL < 0.43; where L is the distance from the diaphragm 6 to the imaging surface on the optical axis, and TTL is the total optical length of the zoom lens. It should be noted that the total optical length is the distance from the center vertex of the object side surface of the first lens 11 to the imaging surface.

[0087] In this embodiment, the ratio of the distance from the diaphragm 6 to the imaging surface to the total optical length of the zoom lens: L / TTL = 0.381.

[0088] Specifically, in this embodiment, the zoom lens further includes a filter, and the filter is located between the fifth lens group 5 and the imaging surface. The filter 7 is used to filter out unnecessary wavelength bands of light and stray light, thereby improving the imaging quality.

[0089] Specifically, the imaging surface can be understood as the surface of the photosensitive chip facing the object side, that is, it can be the surface of a camera element such as a CCD or a CMOS. More specifically, in this embodiment, the imaging surface is the surface of a CMOS solid-state imaging element (the size of the CMOS in this embodiment is 1 / 2.8” inch, H*V = 5.566 mm * 3.13 mm). It can be understood that the light carrying the information of the object to be photographed can sequentially pass through the first lens group 1, the second lens group 2, the diaphragm 6, the third lens group 3, the fourth lens group 4, the fifth lens group 5, the filter and finally form an image on the imaging surface.

[0090] Specifically, the zoom lens satisfies the following conditions: where is the effective aperture of the first lens 11, and TTL is the total optical length of the zoom lens.

[0091] In this embodiment, the ratio of the effective aperture of the first lens 11 to the total optical length of the zoom lens:

[0092] Specifically, the zoom lens satisfies the following condition: 0.271<ΔZ1 W-T / TTL<0.366; where ΔZ W-T is the relative displacement of the second lens group when the zoom lens is at the wide-angle end position and when the zoom lens is at the telephoto end position, and TTL is the total optical length of the zoom lens.

[0093] In this embodiment, the ratio of the movement amount of the second lens group when the zoom lens moves from the wide-angle end to the telephoto end to the total optical length of the zoom lens is: ΔZ1 W-T / TTL=0.311;

[0094] Specifically, the zoom lens satisfies the following condition: 0.026<ΔZ2 W-T / TTL<0.062; where ΔZ2 W-T is the relative displacement of the third lens group when the zoom lens is at the wide-angle end position and when the zoom lens is at the telephoto end position, and TTL is the total optical length of the zoom lens.

[0095] In this embodiment, the ratio of the movement amount of the third lens group when the zoom lens moves from the wide-angle end to the telephoto end to the total optical length of the zoom lens is: ΔZ2 W-T / TTL=0.048.

[0096] Specifically, in this embodiment, the parameters of the zoom lens are as follows:

[0097] Wide-angle focal length fw = 3.38mm, telephoto focal length ft = 40.9mm; wide-angle aperture number Fno w =1.8, telephoto aperture number Fno T =3.4; FOVH at wide angle w =81°, half field of view angle FOVH at telephoto end T =7.5°; the optical distortion range is between -5% and 5%; the total optical length TTL of the zoom lens is 102mm.

[0098] Specifically, in this embodiment, the refractive index, curvature radius, and thickness interval of the lens material are shown in the following table:

[0099] Table 1 Lens parameters

[0100]

[0101]

[0102] Specifically, in this embodiment, the fifth lens, the sixteenth lens, and the seventeenth lens are aspherical plastic lenses, and the ninth lens is an aspherical glass lens. The characteristics of the aspherical lens are: the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After using the aspherical lens, the aberration occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens. The use of a glass lens can reduce the influence of temperature on the optical performance of the lens. The use of a plastic lens can reduce the weight of the optical lens and reduce the cost.

[0103] Further, in this embodiment, the aspheric surface shape of the aspheric lens satisfies the following conditions:

[0104]

[0105] Wherein, c is the curvature corresponding to the radius, y is the radial coordinate (its unit is the same as the lens length unit), k is the coefficient of the conic quadratic curve (when the k coefficient is less than -1, the surface curve is a hyperbola, when the k coefficient is equal to -1, it is a parabola, when the k coefficient is between -1 and 0, it is an ellipse, when the k coefficient is equal to 0, it is a circle, and when the k coefficient is greater than 0, it is an oblate circle), A, B, C, D, E, and F are high-order aspheric coefficients (please refer to Table 2 below). The above parameters can be used to set the shape and size of the aspheric surfaces of the object side and image side of the lens.

[0106] Table 2 Conic coefficients and aspheric coefficients corresponding to aspheric lenses

[0107] R K A B C D E F S8 61.23 -96.94 9.85E-05 -3.01E-05 3.84E-07 7.59E-08 -3.97E-09 3.37E-11 S9 60.39 -11.81 7.97E-04 1.26E-05 -4.80E-06 4.81E-07 -1.87E-08 1.77E-10 S16 14.52 -95.83 3.01E-04 -6.56E-06 1.66E-07 -2.19E-09 1.66E-11 -1.28E-13 S17 -279.46 -98.67 2.15E-04 -7.26E-06 1.66E-07 -8.64E-10 -2.94E-11 2.59E-13 S29 23.50 -8.84 2.44E-04 -6.19E-06 5.08E-08 -1.96E-09 6.87E-11 -1.94E-12 S30 10.93 -35.56 -5.94E-05 -1.36E-06 7.75E-09 -3.01E-09 1.04E-10 -2.15E-12 S31 11.54 -27.38 3.50E-03 -3.34E-04 3.90E-05 -3.70E-06 1.87E-07 -4.97E-09 S32 -30.17 -52.52 4.21E-03 -4.57E-04 5.36E-05 -4.68E-06 1.54E-07 -1.64E-09

[0108] Table 3 Zoom data of zoom lens at wide angle, middle magnification and telephoto end

[0109]

[0110]

[0111] In this embodiment, please refer to Figures 1 to 3 , which are schematic diagrams of the structure of the zoom lens when it is at the wide-angle end, the intermediate magnification, and the telephoto end respectively; wherein the intermediate magnification can be understood as a schematic diagram of the positions of the various lens groups in the zoom lens when the zoom lens is between the wide-angle end and the telephoto end.

[0112] Figures 4 to 6The aberration diagram (longitudinalaberration), field curvature diagram (field curvature) and distortion diagram (distortion) of the zoom lens at the wide-angle end are respectively shown, wherein the d line (λ=588nm), S and T in the diagram are the aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0113] Please refer to Figures 7 to 9 , are aberration diagrams, field curvature diagrams and distortion diagrams when the zoom lens is at an intermediate magnification, wherein the d line (λ=588nm), S and T in the diagram are aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0114] Please refer to Figures 10 to 12 , are spherical aberration diagrams, field curvature diagrams and distortion diagrams when the zoom lens is at the telephoto end, wherein the d line (λ=588nm), S and T in the diagram are aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0115] It can be seen from the above figures that the spherical aberration, field curvature and distortion of the zoom lens in this embodiment can be well corrected at the intermediate magnification, wide-angle end and telephoto end respectively.

[0116] Second embodiment

[0117] Figures 13 to 24 This is a second embodiment of the zoom lens.

[0118] It should be noted that the following embodiments adopt part of the contents of the aforementioned embodiments, omitting the description of the same technical contents. For the same component names, reference may be made to part of the contents of the aforementioned embodiments, which will not be repeated in the following embodiments.

[0119] Compared with the first embodiment, the present embodiment is different in that the seventeenth lens 51 is a concave-convex aspherical plastic lens with positive refractive power.

[0120] Specifically, in this embodiment, the parameters of the zoom lens are as follows:

[0121] Wide-angle focal length fw = 3.42mm, telephoto focal length ft = 41.3mm; wide-angle aperture number Fno w =1.8, telephoto aperture number Fno T =3.4; FOVH at wide angle w =80°, half field of view FOVH at telephoto end T =7.4°; the optical distortion range is between -5% and 5%; the total optical length TTL of the zoom lens is =101.6mm.

[0122] Specifically, in this embodiment, the refractive index, curvature radius, and thickness interval of the lens material are shown in the following table:

[0123] Table 4 Lens parameters

[0124]

[0125]

[0126] Further, in this embodiment, the aspheric surface shape of the aspheric lens satisfies the following conditions:

[0127]

[0128] Wherein, c is the curvature corresponding to the radius, y is the radial coordinate (its unit is the same as the lens length unit), k is the conic quadratic curve coefficient (when the k coefficient is less than -1, the surface curve is a hyperbola, when the k coefficient is equal to -1, it is a parabola, when the k coefficient is between -1 and 0, it is an ellipse, when the k coefficient is equal to 0, it is a circle, and when the k coefficient is greater than 0, it is an oblate circle), A, B, C, D, E, and F are high-order aspheric coefficients (please refer to Table 5 below). The above parameters can be used to set the shape and size of the aspheric surfaces of the object side and image side of the lens.

[0129] Table 5 Conic coefficients and aspheric coefficients corresponding to the aspheric lens in this embodiment

[0130] R K A B C D E F S8 136.74 -59.34 3.31E-04 -7.37E-06 2.20E-07 -2.90E-09 2.41E-11 -1.15E-13 S9 76.90 -63.10 2.67E-04 -7.47E-06 2.24E-07 -2.42E-09 1.25E-11 -9.86E-14 S16 14.19 -8.36 2.52E-04 -6.32E-06 4.69E-08 -3.25E-10 -7.63E-12 -8.33E-13 S17 -228.37 96.32 -6.09E-05 -3.60E-07 -1.18E-07 5.25E-09 -1.51E-10 8.46E-13 S29 18.92 -2.31 -1.50E-04 1.77E-05 -4.37E-06 5.24E-07 -2.82E-08 5.81E-10 S30 14.69 -17.03 9.47E-04 3.13E-05 -1.06E-05 1.39E-06 -8.20E-08 1.93E-09 S31 -470.11 -399.42 -1.43E-04 -6.49E-05 1.33E-05 -2.64E-06 1.61E-07 -3.82E-09 S32 -10.47 -7.81 1.83E-03 -2.11E-04 2.18E-05 -3.33E-06 1.96E-07 -4.13E-09

[0131] Table 6 Zoom data of zoom lens at wide angle, middle magnification and telephoto end

[0132] Wide Angle Intermediate magnification Telephoto T(5) 0.70 27.97 33.88 T(15) 33.75 6.48 0.57 T(ST) 4.55 0.72 0.52 T(21) 11.08 7.10 2.82 T(30) 1.54 9.34 13.83

[0133] It can be seen from the above parameter data that the ratio data of the zoom lens in this embodiment are as follows:

[0134] The ratios of the focal length of the zoom lens at the wide-angle end to the focal lengths of the various lens groups are as follows: fw / f1=0.054; fw / f2=-0.391; fw / f3=0.109; fw / f4=0.145; fw / f5=0.172;

[0135] The focal length ratios of the first lens group 1 and each lens therein are as follows: f1 / f11=-0.653; f1 / f12=0.817; f1 / f13=0.843; f1 / f1112=0.154;

[0136] The focal length ratios of the second lens group 2 and each lens therein are as follows: f2 / f21=0.784; f2 / f22=0.032; f2 / f23=0.304; f2 / f24=0.385; f2 / f25=-0.447;

[0137] The focal length ratios of the third lens group 3 and each lens therein are as follows: f3 / f31=1.462; f3 / f32=0.696; f3 / f33=-1.359;

[0138] The focal length ratios of the fourth lens group 4 and the lenses therein are as follows: f4 / f41=0.773; f4 / f42=1.085; f4 / f43=1.28; f4 / f44=-2.931; f4 / f45=-0.167; f4 / f4344=-1.591;

[0139] The ratio of the distance from the aperture 6 to the imaging plane to the total optical length of the zoom lens is: L / TTL=0.367;

[0140] The ratio of the effective aperture of the first lens 11 to the total optical length of the zoom lens is:

[0141] The ratio of the movement amount of the second lens group when the zoom lens moves from the wide-angle end to the telephoto end to the total optical length of the zoom lens is: ΔZ1 W-T / TTL=0.325;

[0142] The ratio of the movement amount of the third lens group when the zoom lens moves from the wide-angle end to the telephoto end to the total optical length of the zoom lens is: ΔZ2 W-T / TTL=0.04.

[0143] In this embodiment, please refer to Figures 13 to 15 , are schematic diagrams of the structure of the zoom lens when it is at the wide-angle end, the middle magnification, and the telephoto end respectively;

[0144] Please refer to Figures 16 to 18 , are spherical aberration diagrams, field curvature diagrams and distortion diagrams when the zoom lens is at the wide-angle end, wherein the d line (λ=588nm), S and T in the diagram are aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0145] Please refer to Figures 19 to 21 , which are spherical aberration diagrams, field curvature diagrams and distortion diagrams of the zoom lens when it is at an intermediate magnification, wherein the d line (λ=588nm) and S and T in the diagram are aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0146] Please refer to Figure 22 to Figure 24, are spherical aberration diagrams, field curvature diagrams and distortion diagrams when the zoom lens is at the telephoto end, wherein the d line (λ=588nm), S and T in the diagram are aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0147] It can be seen from the above figures that the spherical aberration, field curvature and distortion of the zoom lens in this embodiment can be well corrected at the intermediate magnification, wide-angle end and telephoto end respectively.

[0148] In summary, the zoom lens of the present invention adopts a five-group structure of "positive, negative, positive, positive + aspherical surface", wherein two zoom groups, one focusing group and two fixed groups are provided. With the corresponding movement of the second lens group and the third lens group, the focal length changes. The fourth lens group is used for focusing. (Taking a 1 / 2.8" 16:9 CCD as an example), the focal length can change from <3.5mm at the wide-angle end to >40mm at the telephoto end. The horizontal shooting angle at the wide-angle end (WIDE) is >80°. The optical distortion at the wide-angle end and the telephoto end is within 5%, and the zoom lens has the effects of wide angle, small distortion and large zoom. Moreover, the zoom lens contains three plastic aspherical surfaces and only one glass aspherical surface, which fully reduces the manufacturing cost while ensuring good optical performance.

[0149] Although the zoom lens uses a plastic aspherical lens, the focal length is conditionally limited so that temperature changes have little effect on the performance of the lens, the back focus changes very little, and the performance is stable when the indoor environment changes, without the need for refocusing.

[0150] The zoom lens uses an adjustable aperture, and has an aperture number of 1.8 at the wide-angle end and an aperture number of 3 at the telephoto end. It has extremely high photosensitivity and can capture clearer images even in darker environments.

[0151] The distance between the first lens group and the photosensitive chip is fixed, and the distance between the first lens group and the photosensitive chip is less than 102 mm (taking 1 / 2.8" CCD as an example, if CCDs of other sizes are used, appropriate scaling is performed).

[0152] The zoom lens can achieve a resolution higher than 4K (8 million pixels). Taking a 1 / 2.8" sensor as an example, the present invention can achieve a central resolution higher than 300lp / mm and a peripheral 0.7H (70% diagonal position) resolution higher than 1400TVline.

[0153] In addition, the present invention also provides an imaging device, which includes the zoom lens described in the above technical solution.

[0154] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A zoom lens, characterized in that: The zoom lens has an object side and an image side that are oppositely arranged along the optical axis direction, and the zoom lens includes: a lens barrel; and, a lens group, the lens group includes a first lens group with a positive focal power, a second lens group with a negative focal power, a diaphragm, a third lens group with a positive focal power, a fourth lens group with a positive focal power, a fifth lens group, and an image sensor chip arranged in sequence from the object side to the image side. Among them, the first lens group and the fifth lens group are fixedly installed on the lens barrel, the second lens group, the third lens group, and the fourth lens group are movably installed on the lens barrel along the optical axis direction, the second lens group and the third lens group move cooperatively along the optical axis direction to zoom the zoom lens, and the fourth lens group moves along the optical axis direction to focus the zoom lens; Among them, the zoom lens satisfies the following conditions: 0.046 < fw / f1 < 0.068, and -0.478 < fw / f2 < -0.319, and 0.089 < fw / f3 < 0.134, and 0.113 < fw / f4 < 0.169, and -0.262 < fw / f5 < 0.262; Among them, fw is the focal length of the zoom lens at the wide-angle end, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, and f5 is the focal length of the fifth lens group.

2. The zoom lens according to claim 1, wherein: The first lens group includes a first lens with a negative focal power, a second lens with a positive focal power, and a third lens with a positive focal power arranged in sequence from the object side to the image side; Among them, the first lens group and the first lens, the second lens, and the third lens satisfy the following conditions: -0.783 < f1 / f11 < -0.522, and 0.665 < f1 / f12 < 0.997, and 0.716 < f1 / f13 < 1.074; Among them, f1 is the focal length of the first lens group, f11 is the focal length of the first lens, f12 is the focal length of the second lens, and f13 is the focal length of the third lens.

3. The zoom lens according to claim 1, wherein: The second lens group includes a fourth lens with a negative focal power, a fifth lens, a sixth lens with a negative focal power, a seventh lens with a negative focal power, and an eighth lens with a positive focal power arranged in sequence from the object side to the image side, and the fifth lens is a plastic aspherical lens; Among them, the second lens group and the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy the following conditions: 0.669 < f2 / f21 < 1.004, and -0.089 < f2 / f22 < 0.089, and 0.251 < f2 / f23 < 0.586, and 0.236 < f2 / f24 < 0.55, and -0.628 < f2 / f25 < -0.338; Wherein, f2 is the focal length of the second lens group, f21 is the focal length of the fourth lens, f22 is the focal length of the fifth lens, f23 is the focal length of the sixth lens, f24 is the focal length of the seventh lens, and f25 is the focal length of the eighth lens.

4. The zoom lens according to claim 1, wherein: The third lens group includes a ninth lens with a positive refractive power, a tenth lens with a positive refractive power, and an eleventh lens with a negative refractive power, which are arranged in sequence from the object side to the image side, and the ninth lens is a glass aspherical lens; Wherein, the third lens group, the ninth lens, the tenth lens, and the eleventh lens satisfy the following conditions: 1.114 < f3 / f31 < 2.069, and 0.569 < f3 / f32 < 1.056, and -1.99 < f3 / f33 < -1.071; Wherein, f3 is the focal length of the third lens group, f31 is the focal length of the ninth lens, f32 is the focal length of the tenth lens, and f33 is the focal length of the eleventh lens.

5. The zoom lens according to claim 1, wherein: The fourth lens group includes a twelfth lens with a positive refractive power, a thirteenth lens with a positive refractive power, a fourteenth lens with a positive refractive power, a fifteenth lens with a negative refractive power, and a sixteenth lens, which are arranged in sequence from the object side to the image side, and the sixteenth lens is a plastic aspherical lens; Wherein, the fourth lens group, the twelfth lens, the thirteenth lens, the fourteenth lens, the fifteenth lens, and the sixteenth lens satisfy the following conditions: 0.653 < f4 / f41 < 1.088, and 0.897 < f4 / f42 < 1.666, and 1.122 < f4 / f43 < 1.869, and -4.222 < f4 / f44 < -2.533, and -0.84 < f4 / f45 < 0.252; Wherein, f4 is the focal length of the fourth lens group, f41 is the focal length of the twelfth lens, f42 is the focal length of the thirteenth lens, f43 is the focal length of the fourteenth lens, f44 is the focal length of the fifteenth lens, and f45 is the focal length of the sixteenth lens.

6. The zoom lens according to claim 1, wherein: The fifth lens group includes a seventeenth lens, and the seventeenth lens is a plastic aspherical lens.

7. The zoom lens according to claim 1, wherein: The zoom lens meets the following conditions: in, is the effective clear aperture of the first lens, and TTL is the total optical length of the zoom lens.

8. The zoom lens according to claim 1, wherein: The zoom lens satisfies the following condition: 0.271<ΔZ1 W-T / TTL<0.366; Among them, ΔZ W-T is the relative displacement of the second lens group when the zoom lens is at the wide-angle end position and when the zoom lens is at the telephoto end position, and TTL is the total optical length of the zoom lens.

9. The zoom lens according to claim 1, wherein: The zoom lens satisfies the following condition: 0.026<ΔZ2 W-T / TTL<0.062; Among them, ΔZ2 W-T is the relative displacement of the third lens group when the zoom lens is at the wide-angle end position and when the zoom lens is at the telephoto end position, and TTL is the total optical length of the zoom lens.

10. An imaging device, characterized in that: The imaging device includes the zoom lens according to any one of claims 1-9.

Images