A zoom lens

Abstract

The application discloses a zoom lens. The zoom lens comprises a negative focal length focusing lens group, a diaphragm, a positive focal length zoom lens group and a positive focal length fixed lens group arranged in sequence along an optical axis from an object side to an image side; the diaphragm moves together with the zoom lens group; the zoom lens is switched between a wide-angle end and a long-focus end by changing the positions of the focusing lens group and the zoom lens group on the optical axis; the zoom lens satisfies the conditions of FT / FW=4.5, 4.41<=FOVW / FOVT<=4.88, FT is the focal length of the long-focus end, FW is the focal length of the wide-angle end, FOVW is the maximum field of view angle of the wide-angle end, and FOVT is the maximum field of view angle of the long-focus end. The zoom lens provided by the application uses 11 lenses to form a three-group structure, realizes full-waveband confocal in a 436nm-870nm waveband under a 1 / 1.8" target surface, 4.5 times zoom, has higher image quality, and is suitable for more use requirements.

Description

Technical Field

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

[0002] In the security field, zoom lenses have been widely used due to their advantages such as long shooting distance and large shooting angle. With the development of technology, cameras are gradually moving towards miniaturization and refinement, which also puts more stringent requirements on mainstream zoom lenses.

[0003] Currently, 1 / 1.8″ chips are becoming the mainstream chip on the market and are being used in a wider range of applications. However, traditional zoom lenses usually use 1 / 2.7″ chips, which are difficult to use in a wide range of environments. Traditional zoom lenses also have problems such as small aperture and infrared non-confocality. Therefore, it is necessary to develop a high-image-quality zoom lens with a small size, large aperture, infrared high and low temperature confocality, and compatible with the 1 / 1.8″ chip. Summary of the Invention

[0004] An embodiment of the present invention provides a zoom lens that uses 11 lenses to form a three-element structure. This zoom lens achieves full-band confocality in the 436nm to 870nm band on a 1 / 1.8" target surface, a 4.5x magnification, and higher image quality, making it suitable for use in a wider range of situations.

[0005] According to one aspect of the present invention, there is provided a zoom lens, comprising a focusing lens group with negative optical power, an aperture, a variator lens group with positive optical power, and a fixed lens group with positive optical power, arranged in sequence from the object side to the image side along an optical axis;

[0006] The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power and a fourth lens with negative optical power, wherein the second lens and the third lens form a cemented lens with positive optical power;

[0007] The zoom lens assembly includes a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an eighth lens with positive or negative focal power, a ninth lens with positive or negative focal power, and a tenth lens with negative focal power; the seventh lens and the eighth lens form a cemented lens with positive or negative focal power or can be used separately, and the eighth lens and the ninth lens have opposite focal powers;

[0008] The fixed lens group includes an eleventh lens with positive optical power;

[0009] Wherein, the fourth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens are all aspherical lenses;

[0010] The diaphragm moves together with the zoom lens group, and the zoom lens is switched between the wide-angle end and the telephoto end by changing the positions of the focus lens group and the zoom lens group on the optical axis;

[0011] The zoom lens satisfies the following conditional formula:

[0012] FT / FW=4.5;

[0013] 4.41≤FOVW / FOVT≤4.88;

[0014] Wherein, FT is the focal length of the zoom lens at the telephoto end, FW is the focal length of the zoom lens at the wide-angle end; FOVW is the maximum field of view of the zoom lens at the wide-angle end, and FOVT is the maximum field of view of the zoom lens at the telephoto end.

[0015] Optionally, along the direction from the object side to the image side of the optical axis, in the focusing lens group, the first lens is a convex-concave lens, the second lens is a biconcave lens, the third lens is a biconvex lens, and the object-side surface of the fourth lens is concave;

[0016] In the zoom lens assembly, the fifth lens is a biconvex lens, the sixth lens is a convex-concave lens, the seventh lens is a biconvex lens, the object-side surface of the eighth lens is concave, the object-side surface of the tenth lens is convex at the center and concave at the edge, and the image-side surface is concave at the center and convex at the edge;

[0017] In the fixed lens group, the object side surface of the eleventh lens is marginally convex, and the image side surface is marginally concave.

[0018] Optionally, the focal lengths of the lens groups of the zoom lens and the focal length of the zoom lens at the wide-angle end satisfy the following relationship:

[0019] -2.396≤F1q / FW≤-2.340;

[0020] 2.177≤F2q / FW≤2.235;

[0021] 9.121≤F3q / FW≤12.041;

[0022] Among them, F1q, F2q and F3q represent the focal lengths of the focusing lens group, the zoom lens group and the fixed lens group respectively; FW represents the focal length of the zoom lens at the wide-angle end.

[0023] Optionally, the moving distances of the focusing lens group and the zoom lens group satisfy the following relationship:

[0024] 0.977≤S1 / S2≤1.036;

[0025] Wherein, S1 represents the maximum moving distance of the focusing lens group, and S2 represents the maximum moving distance of the zoom lens group.

[0026] Optionally, the fourth lens, the sixth lens, the ninth lens, the tenth lens, and the eleventh lens are all plastic aspheric lenses, and the fourth lens, the sixth lens, the ninth lens, the tenth lens, and the eleventh lens meet the following requirements:

[0027] 1.535≤nd4≤1.671;19.238≤vd4≤55.709;

[0028] 1.535≤nd6≤1.567;37.401≤vd6≤55.709;

[0029] 1.603≤nd9≤1.629;24.640≤vd9≤28.276;

[0030] 1.535≤nd10≤1.544;55.709≤vd10≤56.135;

[0031] 1.629≤nd11≤1.671;19.238≤vd11≤24.640;

[0032] Wherein, nd4, nd6, nd9, nd10 and nd11 respectively represent the refractive indices of the fourth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens, and vd4, vd6, vd9, vd10 and vd11 respectively represent the Abbe numbers of the fourth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens.

[0033] Optionally, the fifth lens, the seventh lens, and the eighth lens are all glass spherical lenses, and the fifth lens, the seventh lens, and the eighth lens meet the following requirements:

[0034] 1.437≤nd5≤1.497;81.607≤vd5≤95.099;

[0035] 1.437≤nd7≤1.497;81.607≤vd7≤95.099;

[0036] 2.001≤nd8≤2.050;17.303≤vd8≤28.284;

[0037] Wherein, nd5, nd7 and nd8 represent the refractive indices of the fifth lens, the seventh lens and the eighth lens respectively, and vd5, vd7 and vd8 represent the Abbe numbers of the fifth lens, the seventh lens and the eighth lens respectively.

[0038] Optionally, when the eighth lens has positive optical power, the seventh lens and the eighth lens are separated and used.

[0039] Optionally, the focal length of the doublet lens formed by the seventh lens and the eighth lens and the focal length of the zoom lens group satisfy the following relationship:

[0040] -2.205≤F78 / F2q≤0.972;

[0041] Wherein, F78 represents the focal length of the doublet lens composed of the seventh lens and the eighth lens, and F2q represents the focal length of the zoom lens group.

[0042] Optionally, the focal length of the doublet lens formed by the second lens and the third lens and the focal length of the focusing lens group satisfy the following relationship:

[0043] -3.862≤F23 / F1q≤-1.436;

[0044] Wherein, F23 represents the focal length of the doublet lens composed of the second lens and the third lens, and F1q represents the focal length of the focusing lens group.

[0045] Optionally, the total length of the zoom lens and the moving distance of the variable magnification lens group satisfy the following relationship:

[0046] 2.837≤TTL / S2≤2.898;

[0047] Wherein, TTL represents the total length of the zoom lens, and S2 represents the maximum moving distance of the zoom lens group.

[0048] The zoom lens provided by the embodiment of the present invention comprises a focusing lens group with negative focal power, an aperture, a variator lens group with positive focal power, and a fixed lens group with positive focal power, which are arranged in sequence from the object side to the image side along the optical axis; the focusing lens group comprises a first lens group with negative focal power, a second lens group with negative focal power, a third lens group with positive focal power, and a fourth lens group with negative focal power, and the second lens and the third lens group form a cemented lens with positive focal power; the variator lens group comprises a fifth lens group with positive focal power, a sixth lens group with negative focal power, a seventh lens group with positive focal power, and an eighth lens group with positive or negative focal power. The invention relates to a method for obtaining a zoom lens having a focal length of 100 nm and a focal length of 100 nm. The method comprises the following steps: a first lens group, a second lens group, a ninth lens group, a positive or negative optical power lens group, and a negative optical power lens group; the seventh lens group and the eighth lens group form a cemented lens with positive or negative optical power or can be used separately, and the optical powers of the eighth lens and the ninth lens are opposite; the fixed lens group includes an eleventh lens group with positive optical power; wherein the fourth lens group, the sixth lens group, the ninth lens group, the tenth lens group and the eleventh lens group are all aspherical lenses; the aperture moves together with the zoom lens group, and the zoom lens is switched between the wide-angle end and the telephoto end by changing the positions of the focusing lens group and the zoom lens group on the optical axis. According to the technical solution of the embodiment of the present invention, a focusing lens group with negative focal power is used at the front end of the aperture and a fifth lens with positive focal power is used at the rear end of the aperture, which can ensure that a larger light aperture is generated after the light passes through, increase the F number of the zoom lens, and meet the usage requirements under different conditions; the cemented lens used in the focusing lens group can also correct the high-order chromatic aberration and aberration of the lens, control the aberration balance of each group, ensure that no serious aberration is generated when the light enters the structure behind the aperture, and improve the imaging quality of the zoom lens; the aspherical lenses, cemented lenses, etc. of the variable magnification lens group and the fixed lens group can correct the aberration at the rear end of the lens, and can stabilize the imaging quality of the zoom lens in conjunction with the lens group at the front end of the aperture. In addition, controlling the diaphragm diameter at the three ends of the lens to be the same can structurally reduce the aperture range, ensure a longer travel distance for the lens movable group, achieve a higher imaging magnification or reduce the volume, and meet the needs of use under different conditions. By rationally matching the optical focal length, full-band confocality and 4.5x magnification in the 436nm~870nm band can be achieved on a 1 / 1.8″ target surface, achieving higher image quality and suitable for use in a wider range of situations.

[0049] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 these drawings without creative work.

[0051] Figure 1 A schematic structural diagram of a zoom lens at the wide-angle end provided by an embodiment of the present invention;

[0052] Figure 2 for Figure 1 Schematic diagram of the structure of a medium zoom lens at the telephoto end;

[0053] Figure 3 A vertical axis chromatic aberration curve of a zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end;

[0054] Figure 4 An axial aberration diagram of a zoom lens provided by an embodiment of the present invention at an infinite object distance at the wide-angle end;

[0055] Figure 5 A modulation transfer function curve diagram of a zoom lens provided by an embodiment of the present invention at an infinite object distance at the wide-angle end in the visible light band;

[0056] Figure 6 A modulation transfer function curve diagram of a zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the near-infrared band;

[0057] Figure 7 A vertical axis chromatic aberration curve diagram of a zoom lens provided by an embodiment of the present invention at an infinite object distance at the telephoto end;

[0058] Figure 8 An axial aberration diagram of a zoom lens provided by an embodiment of the present invention at an infinite object distance at the telephoto end;

[0059] Figure 9 A modulation transfer function curve diagram of a zoom lens provided by an embodiment of the present invention at the telephoto end in the visible light band at infinite object distance;

[0060] Figure 10 A modulation transfer function curve diagram of a zoom lens provided by an embodiment of the present invention at the telephoto end in the near-infrared band at infinite object distance;

[0061] Figure 11 A schematic structural diagram of another zoom lens at the wide-angle end provided by an embodiment of the present invention;

[0062] Figure 12 for Figure 11 Schematic diagram of the structure of a medium zoom lens at the telephoto end;

[0063] Figure 13 A vertical axis chromatic aberration curve diagram of another zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end;

[0064] Figure 14 Axial aberration diagram of another zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end;

[0065] Figure 15 A modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the visible light band;

[0066] Figure 16 A modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the near-infrared band;

[0067] Figure 17 A vertical axis chromatic aberration curve diagram of another zoom lens provided by an embodiment of the present invention at the telephoto end and infinite object distance;

[0068] Figure 18 Axial aberration diagram of another zoom lens provided by an embodiment of the present invention at the telephoto end and infinite object distance;

[0069] Figure 19 A modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the telephoto end in the visible light band at infinite object distance;

[0070] Figure 20 A modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the telephoto end in the near-infrared band at infinite object distance;

[0071] Figure 21 A schematic structural diagram of another zoom lens at the wide-angle end provided by an embodiment of the present invention;

[0072] Figure 22 for Figure 21 Schematic diagram of the structure of a medium zoom lens at the telephoto end;

[0073] Figure 23 A vertical axis chromatic aberration curve diagram of another zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end;

[0074] Figure 24 Axial aberration diagram of another zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end;

[0075] Figure 25 A modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the visible light band;

[0076] Figure 26 A modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the near-infrared band;

[0077] Figure 27 A vertical axis chromatic aberration curve diagram of another zoom lens provided by an embodiment of the present invention at an infinite object distance at the telephoto end;

[0078] Figure 28 Axial aberration diagram of another zoom lens provided by an embodiment of the present invention at the telephoto end and infinite object distance;

[0079] Figure 29 A modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the telephoto end in the visible light band at infinite object distance;

[0080] Figure 30 This is a modulation transfer function curve diagram of another zoom lens provided by an embodiment of the present invention at the telephoto end and infinite object distance in the near-infrared band. DETAILED DESCRIPTION

[0081] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described 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 making creative efforts should fall within the scope of protection of the present invention.

[0082] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0083] Figure 1 This is a schematic diagram of the structure of a zoom lens at the wide-angle end provided by an embodiment of the present invention. Figure 1The zoom lens provided by the embodiment of the present invention includes a focus lens group 10 with negative focal power, an aperture 20, a variator lens group 30 with positive focal power, and a fixed lens group 40 with positive focal power, which are arranged in sequence from the object side to the image side along the optical axis; the focus lens group 10 includes a first lens 101 with negative focal power, a second lens 102 with negative focal power, a third lens 103 with positive focal power, and a fourth lens 104 with negative focal power, and the second lens 102 and the third lens 103 form a cemented lens with positive focal power; the variator lens group 30 includes a fifth lens 301 with positive focal power, a sixth lens 302 with negative focal power, a seventh lens 303 with positive focal power, and an eighth lens 304 with positive or negative focal power. , a ninth lens 305 with positive or negative focal power, and a tenth lens 306 with negative focal power; the seventh lens 303 and the eighth lens 304 form a cemented lens with positive or negative focal power or can be used separately, and the focal powers of the eighth lens 304 and the ninth lens 305 are opposite; the fixed lens group 40 includes an eleventh lens 401 with positive focal power; wherein the fourth lens 104, the sixth lens 302, the ninth lens 305, the tenth lens 306 and the eleventh lens 401 are all aspherical lenses; the aperture 20 moves together with the zoom lens group 30, and by changing the positions of the focus lens group 10 and the zoom lens group 30 on the optical axis, the zoom lens can be switched between the wide-angle end and the telephoto end;

[0084] The zoom lens meets the following conditions:

[0085] FT / FW=4.5;

[0086] 4.41≤FOVW / FOVT≤4.88;

[0087] Among them, FT is the focal length of the zoom lens at the telephoto end, FW is the focal length of the zoom lens at the wide-angle end; FOVW is the maximum field of view of the zoom lens at the wide-angle end, and FOVT is the maximum field of view of the zoom lens at the telephoto end.

[0088] It is understood that the focal power is the reciprocal of the focal length, which characterizes the ability of an optical system to bend light. The larger the absolute value of the focal power, the stronger the ability to bend light, and the smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is a positive number, the refraction of light is convergent; when the focal power is a negative number, the refraction of light is divergent. In specific implementation, refer to Figure 1 The zoom lens also includes a flat glass 50, which is arranged on the side closest to the image plane. The flat glass 50 can protect the photosensitive chip in the imaging sensor, wherein the photosensitive chip is used to convert the light signal collected by the zoom lens into an electrical signal, thereby ensuring the imaging effect of the zoom lens. The focus lens group 10, the aperture 20, the variable magnification lens group 30, the fixed lens group 40 and the flat glass 50 can be arranged in a lens barrel ( Figure 1(not shown in the figure), the position of the fixed lens group 40 is fixed, and the focal length of the lens is changed by moving the focus lens group 10, the aperture 20 and the zoom lens group 30. In the process of moving the focus lens group 10, the aperture 20 and the zoom lens group 30 to achieve zooming, the zoom lens is at the wide-angle end when the focal length is shortest, and at the telephoto end when the focal length is longest. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical powers, and also has different shapes. It should be noted that Figure 1 The structural diagrams corresponding to the following embodiments are merely illustrative; shapes such as aspheric surfaces are not depicted as they actually are. The opposite focal powers of the eighth lens 304 and the ninth lens 305 mean that when the eighth lens 304 has a positive focal power, the ninth lens 305 has a negative focal power, and when the eighth lens 304 has a negative focal power, the ninth lens 305 has a positive focal power.

[0089] According to the technical solution of the embodiment of the present invention, a focusing lens group with negative focal power is used at the front end of the aperture and a fifth lens with positive focal power is used at the rear end of the aperture, which can ensure that a larger light aperture is generated after the light passes through, increase the F number of the zoom lens, and meet the usage requirements under different conditions; the cemented lens used in the focusing lens group can also correct the high-order chromatic aberration and aberration of the lens, control the aberration balance of each group, ensure that no serious aberration is generated when the light enters the structure behind the aperture, and improve the imaging quality of the zoom lens; the aspherical lenses, cemented lenses, etc. of the variable magnification lens group and the fixed lens group can correct the aberration at the rear end of the lens, and can stabilize the imaging quality of the zoom lens in conjunction with the lens group at the front end of the aperture. In addition, controlling the diaphragm diameter at the three ends of the lens to be the same can structurally reduce the aperture range, ensure a longer travel distance for the lens movable group, achieve a higher imaging magnification or reduce the volume, and meet the needs of use under different conditions. By rationally matching the optical focal length, full-band confocality and 4.5x magnification in the 436nm~870nm band can be achieved on a 1 / 1.8″ target surface, achieving higher image quality and suitable for use in a wider range of situations.

[0090] On the basis of the above embodiments, optionally, along the direction from the object side to the image side of the optical axis, in the focusing lens group 10, the first lens 101 is a convex-concave lens, the second lens 102 is a biconcave lens, the third lens 103 is a biconvex lens, and the object side surface of the fourth lens 104 is concave; in the zoom lens group 30, the fifth lens 301 is a biconvex lens, the sixth lens 302 is a convex-concave lens, the seventh lens 303 is a biconvex lens, the object side surface of the eighth lens 304 is concave, the object side surface of the tenth lens 306 is a center-convex and edge-concave type, and the image side surface is a center-concave and edge-convex type; in the fixed lens group 40, the object side surface of the eleventh lens 401 is edge-convex, and the image side surface is edge-concave.

[0091] By setting the shape of each lens, the optical power of each lens can be adapted.

[0092] Optionally, the focal lengths of the lens groups of the zoom lens and the focal length of the zoom lens at the wide-angle end satisfy the following relationship:

[0093] -2.396≤F1q / FW≤-2.340;

[0094] 2.177≤F2q / FW≤2.235;

[0095] 9.121≤F3q / FW≤12.041;

[0096] Wherein, F1q, F2q and F3q represent the focal lengths of the focus lens group 10, the variable power lens group 30 and the fixed lens group 40 respectively; and FW represents the focal length of the zoom lens at the wide-angle end.

[0097] By setting the focal length of each lens group and the focal length of the zoom lens at the wide-angle end to meet the above-mentioned matching method, a reasonable matching of optical focal lengths is achieved, allowing light to pass through the zoom lens more smoothly, thereby correcting the influence of high-level aberrations on image quality to a great extent.

[0098] Optionally, the moving distances of the focus lens group 10 and the zoom lens group 30 satisfy the following relationship:

[0099] 0.977≤S1 / S2≤1.036;

[0100] Here, S1 represents the maximum moving distance of the focus lens group 10 , and S2 represents the maximum moving distance of the zoom lens group 30 .

[0101] By controlling the moving distance of the focus lens group 10 and the zoom lens group 30, the size of the lens can be minimized. The closer the value is to 1, the higher the space utilization of the zoom lens group and the focus lens group.

[0102] Optionally, the fourth lens 104 , the sixth lens 302 , the ninth lens 305 , the tenth lens 306 , and the eleventh lens 401 are all plastic aspheric lenses, and the fourth lens 104 , the sixth lens 302 , the ninth lens 305 , the tenth lens 306 , and the eleventh lens 401 meet the following requirements:

[0103] 1.535≤nd4≤1.671;19.238≤vd4≤55.709;

[0104] 1.535≤nd6≤1.567;37.401≤vd6≤55.709;

[0105] 1.603≤nd9≤1.629;24.640≤vd9≤28.276;

[0106] 1.535≤nd10≤1.544;55.709≤vd10≤56.135;

[0107] 1.629≤nd11≤1.671;19.238≤vd11≤24.640;

[0108] Wherein, nd4, nd6, nd9, nd10 and nd11 respectively denote the refractive indices of the fourth lens 104, the sixth lens 302, the ninth lens 305, the tenth lens 306 and the eleventh lens 401, and vd4, vd6, vd9, vd10 and vd11 respectively denote the Abbe numbers of the fourth lens 104, the sixth lens 302, the ninth lens 305, the tenth lens 306 and the eleventh lens 401.

[0109] In order to ensure that the zoom lens can achieve stable imaging at all focal lengths, it is usually necessary to separately achromatize and control aberrations in the fixed lens group 40 to prevent excessive accumulation of chromatic aberration and aberration after entering the movable lens group 30, thereby affecting image quality. The fourth lens 104 uses the above-mentioned lens material combination to control the chromatic aberration and aberration entering the focus lens group 10 within a reasonable range, preventing them from being excessively amplified during the movement of the focus lens group 10, making them difficult to correct later. In the focus lens group 10, the sixth lens 302, the ninth lens 305, and the tenth lens 306 use the above-mentioned lens material combination to correct the chromatic aberration and aberration generated by the entire lens, controlling them within a reasonable range before the light enters the image plane. In addition, aspherical lenses have an excellent ability to control the higher-order aberrations of the optical system. The use of aspherical lenses in the fourth lens 104, the sixth lens 302, the ninth lens 305, the tenth lens 306, and the eleventh lens 401 can further reduce the higher-order aberrations when the light enters the image plane, thereby further improving image quality and meeting the requirements of 4K imaging.

[0110] In addition, glass and plastic can compensate for each other and can effectively balance the expansion and contraction of the front and rear ends of the lens under temperature changes, which is beneficial to improving the overall high and low temperature performance of the lens. The combination of glass and plastic lenses in the lens can better balance the resolution of the lens under high and low temperature conditions. At the same time, the use of a reasonable combination of glass lenses can also have a good correction effect on the aberration of the lens. The use of the above materials can ensure that the lens has good resolution within the range of -40°C to 80°C. The use of the above plastic lens combination can meet the requirements of good resolution under the above temperature conditions, expanding the scope of use of the lens. The material of the plastic aspheric lens is various types of plastic known to those skilled in the art, and the embodiments of the present invention will not be described in detail.

[0111] Optionally, the fifth lens 301 , the seventh lens 303 , and the eighth lens 304 are all glass spherical lenses, and the fifth lens 301 , the seventh lens 303 , and the eighth lens 304 meet the following requirements:

[0112] 1.437≤nd5≤1.497;81.607≤vd5≤95.099;

[0113] 1.437≤nd7≤1.497;81.607≤vd7≤95.099;

[0114] 2.001≤nd8≤2.050;17.303≤vd8≤28.284;

[0115] Wherein, nd5, nd7 and nd8 represent the refractive indices of the fifth lens 301, the seventh lens 303 and the eighth lens 304 respectively, and vd5, vd7 and vd8 represent the Abbe numbers of the fifth lens 301, the seventh lens 303 and the eighth lens 304 respectively.

[0116] For the zoom lens group 30, after the light passes through the focusing lens group 10, despite the correction of the aspherical lens in front, the overall chromatic aberration of the light is still very large. In order to eliminate the chromatic aberration, the fifth lens 301 uses a material with a high Abbe number. After the light enters the zoom lens group 30, it is achromatic, reducing the influence of the zoom lens group 30 on its chromatic aberration.

[0117] According to the achromatic aberration requirements for doublets, a doublet lens with a certain optical power can only be achromatized by using two different glasses (the Abbe number of the front lens of the doublet is not equal to the Abbe number of the rear lens of the doublet). Furthermore, to minimize the focal power of the front lens and the rear lens of the doublet, the difference in the Abbe constants of the two glasses should be as large as possible. Crown glass and flint glass are commonly used. The former has a higher Abbe number, while the latter has a lower one. Therefore, in the doublet lens consisting of the seventh lens 303 and the eighth lens 304, using a combination with a large difference in Abbe number can further eliminate chromatic aberration in the optical system, thereby achieving full confocality in the 436nm to 870nm band.

[0118] Optionally, when the eighth lens 304 has positive power, the seventh lens 303 and the eighth lens 304 can be used separately. The fixed lens group 40 includes an aspherical lens. This aspherical lens can effectively correct aberrations and reduce the CRA (chief ray angle) before light reaches the image plane, effectively improving image quality and compatibility with most 1 / 1.8" chips on the market.

[0119] Optionally, the focal length of the doublet lens formed by the seventh lens 303 and the eighth lens 304 and the focal length of the zoom lens group 30 satisfy the following relationship:

[0120] -2.205≤F78 / F2q≤0.972;

[0121] Wherein, F78 represents the focal length of the doublet lens composed of the seventh lens 303 and the eighth lens 304 , and F2q represents the focal length of the variator lens group 30 .

[0122] During the zooming process of the zoom lens, the zoom lens group 30 is responsible for zooming the lens. The use of aspherical lenses and cemented lenses can correct the chromatic aberration and higher-order aberrations generated in the zoom lens group 30, greatly reducing the aberration pressure of other groups of the zoom lens at different focal lengths, thereby achieving focusing of the zoom lens at the full focal length.

[0123] Optionally, the focal length of the doublet lens formed by the second lens 102 and the third lens 103 and the focal length of the focusing lens group 10 satisfy the following relationship:

[0124] -3.862≤F23 / F1q≤-1.436;

[0125] Wherein, F23 represents the focal length of the doublet lens composed of the second lens 102 and the third lens 103 , and F1q represents the focal length of the focusing lens group 10 .

[0126] By using the above focal length combination in the focus lens group 10 of the zoom lens, light can pass through the front end of the lens smoothly, and before the light enters the zoom lens group 30, the chromatic aberration and aberration generated at the front end are reduced, further improving the image quality.

[0127] Optionally, the total length of the zoom lens and the moving distance of the zoom lens group 30 satisfy the following relationship:

[0128] 2.837≤TTL / S2≤2.898;

[0129] Here, TTL represents the total length of the zoom lens, and S2 represents the maximum moving distance of the zoom lens group 30 .

[0130] The limitation of the zoom lens group 30 and the total length of the lens can compress the lens space, ensuring that the required imaging quality and zoom level are met under the condition of a small lens volume.

[0131] In an embodiment of the present invention, the aspherical lens of the zoom lens satisfies the following formula:

[0132] ;

[0133] 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; k is the fitting cone coefficient; 、 、 、 、 、 are the high-order aspheric coefficients corresponding to the fourth, sixth, eighth, tenth, twelfth, and fourteenth orders of the aspheric surface, Combined into high-order terms corresponding to aspheric surfaces.

[0134] For example, Figure 2 for Figure 1 The structure diagram of the medium zoom lens at the telephoto end is shown in Table 1. Figure 1 and Figure 2 Specific parameters of the corresponding zoom lens:

[0135] Table 1 Specific parameters of zoom lens

[0136]

[0137] Table 2 is Figure 1 and Figure 2 The specific design values ​​of the zoom lens parameters are as follows:

[0138] Table 2 Design values ​​of various lens parameters of zoom lens

[0139]

[0140] The surface numbers in Table 2 are numbered according to the order of the surfaces of each lens. Surface numbers 4 and 14 represent the cemented surfaces of a doublet lens, "STO" represents the aperture of a zoom lens, and IMA represents the image plane. The radius of curvature represents the degree of curvature of the corresponding 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 units of the radius of curvature and thickness are both millimeters. Material (nd) is the refractive index, which indicates the light refracting ability of the material between the current surface and the next surface. A blank space indicates that the current position is air, with a refractive index of 1. Material (vd) is the Abbe number, which indicates the light dispersion characteristics of the material between the current surface and the next surface.

[0141] Table 3 shows the zoom interval values ​​in Table 2:

[0142] Table 3 Zoom intervals at the wide-angle and telephoto ends of a zoom lens

[0143]

[0144] Table 4 is Figure 1 and Figure 2 Aspheric surface parameters of medium zoom lens:

[0145] Table 4 Aspheric parameters of zoom lens

[0146]

[0147] Table 4

[0148]

[0149] Among them, -7.65260999E-04 represents the number of face 6. The coefficient is .

[0150] Table 5 shows the performance indicators achieved by this embodiment:

[0151] Table 5 Performance indicators of zoom lenses

[0152]

[0153] Figure 3 This is a vertical axis chromatic aberration curve for a zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end. The vertical axis represents the field of view, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546nm, and the horizontal axis represents the offset relative to the main wavelength, in microns (μm). Figure 3 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of this zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0154] Figure 4 This is a diagram of the axial aberration of a zoom lens at infinite object distance at the wide-angle end, provided by an embodiment of the present invention. Axial aberration diagrams are a common evaluation method used by optical designers. The vertical axis represents the normalized aperture, with 0 representing the optical axis and the vertex representing the maximum pupil radius. The horizontal axis represents the offset from the ideal focus, measured in millimeters (mm). Figure 4 The different linear curves represent the different wavelengths of the system imaging, which are represented by Figure 4 It can be seen that the axial aberration of the normalized aperture of 0~1.0 at different wavelengths is controlled within the range of (-0.02mm, +0.02mm), indicating that the spherical aberration of this zoom lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0155] Figure 5This is a graph showing the modulation transfer function (MTF) of a zoom lens at the wide-angle end and infinite object distance in the visible light band, provided by an embodiment of the present invention. The vertical axis represents the modulation transfer function (MTF) value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated visible light band ranges from 436nm to 656nm, with a dominant wavelength of 546nm. Figure 5 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. Among them, at 120 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.35, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0156] Figure 6 This is a graph showing the modulation transfer function (MTF) of a zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the near-infrared band. The vertical axis represents the MTF value, in units of N / A; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated infrared band ranges from 830nm to 870nm, with a dominant wavelength of 850nm. Figure 6 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 60 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.4, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0157] Figure 7 This is a vertical axis chromatic aberration curve for a zoom lens provided by an embodiment of the present invention at the telephoto end and infinite object distance. The vertical axis represents the field of view, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546nm, and the horizontal axis represents the offset relative to the main wavelength, in microns (μm). Figure 7 It can be seen that the vertical chromatic aberration at different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the telephoto end is well controlled and can meet application requirements under normal conditions.

[0158] Figure 8 This is a diagram of the axial aberration of a zoom lens at infinite object distance at the telephoto end, provided by an embodiment of the present invention. Axial aberration diagrams are a common evaluation method used by optical designers. The vertical axis represents the normalized aperture, with 0 being on the optical axis and the vertex representing the maximum pupil radius. The horizontal axis represents the offset from the ideal focus, measured in millimeters (mm). Figure 8 The different linear curves represent the different wavelengths of the system imaging, which are represented by Figure 8It can be seen that the axial aberration of the normalized aperture of 0~1.0 at different wavelengths is controlled within the range of (-0.02mm, +0.02mm), indicating that the spherical aberration of this zoom lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0159] Figure 9 This is a graph of the modulation transfer function (MTF) of a zoom lens provided by an embodiment of the present invention at the telephoto end in the visible light band at infinite object distance. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated visible light band ranges from 436nm to 656nm, with a dominant wavelength of 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 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.5, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0160] Figure 10 This is a graph showing the modulation transfer function (MTF) of a zoom lens provided by an embodiment of the present invention at the telephoto end in the near-infrared band at infinite object distance. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated infrared band ranges from 830nm to 870nm, with a dominant wavelength of 850nm. Figure 10 It can be seen that the modulation transfer function values ​​for each frequency at different fields of view are all within reasonable ranges. At 60 line pairs / mm, the modulation transfer function values ​​within a field of view are all greater than 0.6, and the MTF for each field of view approaches the diffraction limit. This demonstrates that the zoom optical system has excellent image quality control at the wide-angle end, meeting the requirements of 4K cameras.

[0161] Figure 11 This is a schematic structural diagram of another zoom lens at the wide-angle end provided by an embodiment of the present invention. Figure 12 for Figure 11 The structure diagram of the medium zoom lens at the telephoto end is shown in Table 6. Figure 11 and Figure 12 Specific parameters of the corresponding zoom lens:

[0162] Table 6 Specific parameters of zoom lens

[0163]

[0164] Table 7 is Figure 11 and Figure 12 The specific design values ​​of the zoom lens parameters are as follows:

[0165] Table 7 Design values ​​of various lens parameters of zoom lens

[0166]

[0167] The surface numbers in Table 7 are numbered according to the order of the surfaces of each lens. Surface numbers 4 and 14 represent the cemented surfaces of a doublet lens, "STO" represents the aperture of a zoom lens, and IMA represents the image plane. The radius of curvature represents the degree of curvature of the corresponding 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 units of the radius of curvature and thickness are both millimeters. Material (nd) is the refractive index, which indicates the light refracting ability of the material between the current surface and the next surface. A blank space indicates that the current position is air, with a refractive index of 1. Material (vd) is the Abbe number, which indicates the light dispersion characteristics of the material between the current surface and the next surface.

[0168] Table 8 shows the zoom interval values ​​in Table 7:

[0169] Table 8 Zoom intervals at the wide-angle and telephoto ends of a zoom lens

[0170]

[0171] Table 9 is Figure 11 and Figure 12 Aspheric surface parameters of medium zoom lens:

[0172] Table 9 Aspheric parameters of zoom lens

[0173]

[0174] Table 9

[0175]

[0176] Among them, -2.46274877E-07 represents the number of face 6. The coefficient is .

[0177] Table 10 shows the performance indicators achieved by this embodiment:

[0178] Table 10 Performance indicators of zoom lenses

[0179]

[0180] Figure 13 This is a vertical chromatic aberration curve for another zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end. The vertical axis represents the field of view, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546nm, and the horizontal axis represents the offset relative to the main wavelength, in microns (μm). Figure 13 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of this zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0181] Figure 14 This is a diagram of the axial aberration of another zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end. Axial aberration diagrams are a common evaluation method used by optical designers. The vertical axis represents the normalized aperture, with 0 representing the optical axis and the vertex representing the maximum pupil radius. The horizontal axis represents the offset from the ideal focus, measured in millimeters (mm). Figure 14 The different linear curves represent the different wavelengths of the system imaging, which are represented by Figure 14 It can be seen that the axial aberration of the normalized aperture of 0~1.0 at different wavelengths is controlled within the range of (-0.02mm, +0.025mm), indicating that the spherical aberration of this zoom lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0182] Figure 15 This is a graph showing the modulation transfer function (MTF) of another zoom lens provided by an embodiment of the present invention at infinite object distance at the wide-angle end in the visible light band. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated visible light band ranges from 436nm to 656nm, with a dominant wavelength of 546nm. Figure 15 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. Among them, at 120 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.4, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0183] Figure 16 This is a graph showing the modulation transfer function (MTF) of another zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the near-infrared band. The vertical axis represents the MTF value, in units of N / A; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated infrared band ranges from 830nm to 870nm, with a dominant wavelength of 850nm. Figure 16 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 60 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.5, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0184] Figure 17This is a vertical chromatic aberration curve for another zoom lens provided by an embodiment of the present invention at the telephoto end and infinite object distance. The vertical axis represents the field of view, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546nm, and the horizontal axis represents the offset relative to the main wavelength, in microns (μm). Figure 17 It can be seen that the vertical chromatic aberration at different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the telephoto end is well controlled and can meet application requirements under normal conditions.

[0185] Figure 18 This is a diagram of the axial aberration of a zoom lens at infinite object distance at the telephoto end, provided by an embodiment of the present invention. Axial aberration diagrams are a common evaluation method used by optical designers. The vertical axis represents the normalized aperture, with 0 being on the optical axis and the vertex representing the maximum pupil radius. The horizontal axis represents the offset from the ideal focus, measured in millimeters (mm). Figure 18 The different linear curves represent the different wavelengths of the system imaging, which are represented by Figure 18 It can be seen that the axial aberration of the normalized aperture of 0~1.0 at different wavelengths is controlled within the range of (-0.025mm, +0.02mm), indicating that the spherical aberration of this zoom lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0186] Figure 19 This is a graph showing the modulation transfer function (MTF) of another zoom lens provided by an embodiment of the present invention at the telephoto end in the visible light band at infinite object distance. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated visible light band ranges from 436nm to 656nm, with a dominant wavelength of 546nm. Figure 19 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 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.4, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0187] Figure 20 This is a graph showing the modulation transfer function (MTF) of another zoom lens provided by an embodiment of the present invention at the telephoto end in the near-infrared band at infinite object distance. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated infrared band ranges from 830nm to 870nm, with a dominant wavelength of 850nm. Figure 20It can be seen that the modulation transfer function values ​​for each frequency at different fields of view are all within reasonable ranges. At 60 line pairs / mm, the modulation transfer function values ​​within a field of view are all greater than 0.5, and the MTF across all fields of view approaches the diffraction limit. This demonstrates that the zoom optical system has excellent image quality control at the wide-angle end, meeting the requirements of 4K cameras.

[0188] Figure 21 A schematic structural diagram of another zoom lens at the wide-angle end provided by an embodiment of the present invention is shown. Figure 22 for Figure 21 The structure diagram of the medium zoom lens at the telephoto end is shown in Table 11. Figure 21 and Figure 22 Specific parameters of the corresponding zoom lens:

[0189] Table 11 Specific parameters of zoom lens

[0190]

[0191] Table 12 is Figure 21 and Figure 22 The specific design values ​​of the zoom lens parameters are as follows:

[0192] Table 12 Design values ​​of various lens parameters of zoom lens

[0193]

[0194] The surface numbers in Table 12 are numbered according to the order of the surfaces of each lens. Surface numbers 4 and 14 represent the cemented surfaces of a doublet lens, "STO" represents the aperture of a zoom lens, and IMA represents the image plane. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value represents that the surface is curved toward the image plane, and a negative value represents 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 units of the radius of curvature and thickness are both millimeters. Material (nd) is the refractive index, which represents the light refracting ability of the material between the current surface and the next surface. A blank space represents that the current position is air, with a refractive index of 1. Material (vd) is the Abbe number, which represents the light dispersion characteristics of the material between the current surface and the next surface.

[0195] Table 13 shows the zoom interval values ​​in Table 12:

[0196] Table 13 Zoom intervals at the wide-angle and telephoto ends of a zoom lens

[0197]

[0198] Table 14 is Figure 21 and Figure 22 Aspheric surface parameters of medium zoom lens:

[0199] Table 14 Aspheric parameters of zoom lens

[0200]

[0201] Table 14

[0202]

[0203] Among them, -7.14979396E-05 represents the surface number 6 The coefficient is .

[0204] Table 15 shows the performance indicators achieved by this embodiment:

[0205] Table 15 Performance indicators of zoom lenses

[0206]

[0207] Figure 23 This is a vertical chromatic aberration curve for another zoom lens at infinite object distance at the wide-angle end provided by an embodiment of the present invention. The vertical axis represents the field of view, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546nm, and the horizontal axis represents the offset relative to the main wavelength, in microns (μm). Figure 23 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of this zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0208] Figure 24 This is an axial aberration diagram of another zoom lens at infinite object distance at the wide-angle end, provided by an embodiment of the present invention. Axial aberration diagrams are a common evaluation method used by optical designers. The vertical axis represents the normalized aperture, with 0 representing the optical axis and the vertex representing the maximum pupil radius. The horizontal axis represents the offset from the ideal focus, measured in millimeters (mm). Figure 24 The different linear curves represent the different wavelengths of the system imaging, which are represented by Figure 24 It can be seen that the axial aberration of the normalized aperture of 0~1.0 at different wavelengths is controlled within the range of (-0.02mm, +0.025mm), indicating that the spherical aberration of this zoom lens at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0209] Figure 25This is a graph showing the modulation transfer function (MTF) of another zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the visible light band. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated visible light band ranges from 436nm to 656nm, with a dominant wavelength of 546nm. 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 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.45, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0210] Figure 26 This is a graph showing the modulation transfer function of another zoom lens provided by an embodiment of the present invention at the wide-angle end and infinite object distance in the near-infrared band. The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm (line pairs / mm). The simulated infrared band range is 830nm~870nm, and the dominant wavelength is 850nm. Figure 26 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 60 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.3, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0211] Figure 27 This is a vertical chromatic aberration curve for another zoom lens at infinite object distance at the telephoto end provided by an embodiment of the present invention. The vertical axis represents the field of view, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546nm, and the horizontal axis represents the offset relative to the main wavelength, in microns (μm). Figure 27 It can be seen that the vertical chromatic aberration at different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the telephoto end is well controlled and can meet application requirements under normal conditions.

[0212] Figure 28 This is an axial aberration diagram of another zoom lens at infinite object distance at the telephoto end, provided by an embodiment of the present invention. Axial aberration diagrams are a common evaluation method used by optical designers. The vertical axis represents the normalized aperture, with 0 representing the optical axis and the vertex representing the maximum pupil radius. The horizontal axis represents the offset from the ideal focus, measured in millimeters (mm). Figure 28 The different linear curves represent the different wavelengths of the system imaging, which are represented by Figure 28It can be seen that the axial aberration of the normalized aperture of 0~1.0 at different wavelengths is controlled within the range of (-0.025mm, +0.02mm), indicating that the spherical aberration of this zoom lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0213] Figure 29 This is a graph showing the modulation transfer function (MTF) of another zoom lens provided by an embodiment of the present invention at the telephoto end in the visible light band at infinite object distance. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated visible light band ranges from 436nm to 656nm, with a dominant wavelength of 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 line pairs / mm, the modulation transfer function values ​​within one field of view are all greater than 0.5, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0214] Figure 30 This is a graph showing the modulation transfer function (MTF) of a zoom lens provided by an embodiment of the present invention at the telephoto end in the near-infrared band at infinite object distance. The vertical axis represents the MTF value, in units of zero; the horizontal axis represents the spatial frequency, in units of cyc / mm (line pairs / mm). The simulated infrared band ranges from 830nm to 870nm, with a dominant wavelength of 850nm. Figure 30 It can be seen that the modulation transfer function values ​​for each frequency at different fields of view are all within reasonable ranges. At 60 line pairs / mm, the modulation transfer function values ​​within a field of view are all greater than 0.6, and the MTF for each field of view approaches the diffraction limit. This demonstrates that the zoom optical system has excellent image quality control at the wide-angle end, meeting the requirements of 4K cameras.

[0215] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A zoom lens, characterized in that: The lens comprises a focusing lens group with negative optical power, an aperture, a variable magnification lens group with positive optical power, and a fixed lens group with positive optical power, which are arranged in sequence from the object side to the image side along the optical axis; The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power and a fourth lens with negative optical power, wherein the second lens and the third lens form a cemented lens with positive optical power; The zoom lens assembly includes a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an eighth lens with positive or negative focal power, a ninth lens with positive or negative focal power, and a tenth lens with negative focal power; the seventh lens and the eighth lens form a cemented lens with positive or negative focal power or can be used separately, and the eighth lens and the ninth lens have opposite focal powers; The fixed lens group includes an eleventh lens with positive optical power; Wherein, the fourth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens are all aspherical lenses; The diaphragm moves together with the zoom lens group, and the zoom lens is switched between the wide-angle end and the telephoto end by changing the positions of the focus lens group and the zoom lens group on the optical axis; The zoom lens satisfies the following conditional formula: FT / FW=4.5; 4.41≤FOVW / FOVT≤4.88; Wherein, FT is the focal length of the zoom lens at the telephoto end, FW is the focal length of the zoom lens at the wide-angle end; FOVW is the maximum field of view of the zoom lens at the wide-angle end, and FOVT is the maximum field of view of the zoom lens at the telephoto 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, in the focusing lens group, the first lens is a convex-concave lens, the second lens is a biconcave lens, the third lens is a biconvex lens, and the object-side surface of the fourth lens is concave; In the zoom lens assembly, the fifth lens is a biconvex lens, the sixth lens is a convex-concave lens, the seventh lens is a biconvex lens, the object-side surface of the eighth lens is concave, the object-side surface of the tenth lens is convex at the center and concave at the edge, and the image-side surface is concave at the center and convex at the edge; In the fixed lens group, the object side surface of the eleventh lens is marginally convex, and the image side surface is marginally concave.

3. The zoom lens according to claim 1, wherein: The focal lengths of the lens groups of the zoom lens and the focal length of the zoom lens at the wide-angle end satisfy the following relationship: -2.396≤F1q / FW≤-2.340; 2.177≤F2q / FW≤2.235; 9.121≤F3q / FW≤12.041; Wherein, F1q, F2q and F3q represent the focal lengths of the focusing lens group, the variable magnification lens group and the fixed lens group respectively; and FW represents the focal length of the zoom lens at the wide-angle end.

4. The zoom lens according to claim 1, wherein: The moving distances of the focus lens group and the zoom lens group satisfy the following relationship: 0.977≤S1 / S2≤1.036; Wherein, S1 represents the maximum moving distance of the focusing lens group, and S2 represents the maximum moving distance of the zoom lens group.

5. The zoom lens according to claim 1, wherein: The fourth lens, the sixth lens, the ninth lens, the tenth lens, and the eleventh lens are all plastic aspheric lenses, and the fourth lens, the sixth lens, the ninth lens, the tenth lens, and the eleventh lens meet the following requirements: 1.535≤nd4≤1.671;19.238≤vd4≤55.709; 1.535≤nd6≤1.567;37.401≤vd6≤55.709; 1.603≤nd9≤1.629;24.640≤vd9≤28.276; 1.535≤nd10≤1.544;55.709≤vd10≤56.135; 1.629≤nd11≤1.671;19.238≤vd11≤24.640; Wherein, nd4, nd6, nd9, nd10 and nd11 respectively represent the refractive indices of the fourth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens, and vd4, vd6, vd9, vd10 and vd11 respectively represent the Abbe numbers of the fourth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens.

6. The zoom lens according to claim 1, wherein: The fifth lens, the seventh lens, and the eighth lens are all glass spherical lenses, and the fifth lens, the seventh lens, and the eighth lens meet the following requirements: 1.437≤nd5≤1.497;81.607≤vd5≤95.099; 1.437≤nd7≤1.497;81.607≤vd7≤95.099; 2.001≤nd8≤2.050;17.303≤vd8≤28.284; Wherein, nd5, nd7 and nd8 represent the refractive indices of the fifth lens, the seventh lens and the eighth lens respectively, and vd5, vd7 and vd8 represent the Abbe numbers of the fifth lens, the seventh lens and the eighth lens respectively.

7. The zoom lens according to claim 1, wherein: When the eighth lens has positive refractive power, the seventh lens and the eighth lens are separated and used.

8. The zoom lens according to claim 1, wherein: The focal length of the doublet lens composed of the seventh lens and the eighth lens and the focal length of the zoom lens group satisfy the following relationship: -2.205≤F78 / F2q≤0.972; Wherein, F78 represents the focal length of the doublet lens composed of the seventh lens and the eighth lens, and F2q represents the focal length of the zoom lens group.

9. The zoom lens according to claim 1, wherein: The focal length of the doublet lens composed of the second lens and the third lens and the focal length of the focusing lens group satisfy the following relationship: -3.862≤F23 / F1q≤-1.436; Wherein, F23 represents the focal length of the doublet lens composed of the second lens and the third lens, and F1q represents the focal length of the focusing lens group.

10. The zoom lens according to claim 1, wherein The total length of the zoom lens and the moving distance of the zoom lens group satisfy the following relationship: 2.837≤TTL / S2≤2.898; Wherein, TTL represents the total length of the zoom lens, and S2 represents the maximum moving distance of the zoom lens group.

Images