Zoom lens

Abstract

The invention discloses a zoom lens which comprises a first fixed lens group with positive focal power, a zoom lens group with negative focal power, a diaphragm, a second fixed lens group with positive focal power, a focusing lens group with positive focal power, a third fixed lens group with positive focal power and plate glass which are sequentially arranged from an object space to an image space along an optical axis, the first fixed lens group sequentially comprises a negative lens, a positive lens and a positive lens; the zoom lens group sequentially comprises a negative lens, a negative lens and a positive lens; the second fixed lens group sequentially comprises a positive lens, a negative lens, a positive lens, a negative lens, a positive lens, a negative lens and a positive lens, the front three lenses comprise at least two doublet lenses, and the rear three lenses comprise at least two doublet lenses; the focusing lens group comprises a positive lens; the third fixed lens group includes a lens having a focal power. The lens has the advantages of being large in aperture, small in distortion, long in focal length and high in imaging definition, and can meet the use requirements under the 1 / 1.2 ''target surface and the wave band of 436-850 nm.

Description

Technical Field

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

[0002] ITS (Intelligent Transportation System) lens is a lens specially designed for image sensors. ITS lens usually has the characteristics of high resolution, low distortion, high contrast, etc., and can provide clear, accurate, high-quality images. Its design takes into account the optical characteristics, mechanical structure and electronic interface, and can effectively adapt to various complex environments.

[0003] Currently, most of the ITS lenses commonly used on the market are fixed-focus lenses with low image quality and poor tolerance in harsh environments. Faced with more complex usage environments, zoom lenses have gradually become the new favorite in the ITS field, but the types of zoom lenses for the ITS field on the market are extremely limited, and there are problems such as low image quality, too small focal length range, and large distortion, which have certain difficulties in practical application. Summary of the invention

[0004] The invention provides a zoom lens, which has the characteristics of large aperture, small distortion, long focal length and high-definition imaging, and can meet the use requirements in the 436nm-850nm band under a 1 / 1.2″ target surface.

[0005] To achieve the above object, an embodiment of the present invention provides a zoom lens, comprising: a first fixed lens group with positive optical power, a variable magnification lens group with negative optical power, an aperture, a second fixed lens group with positive optical power, a focusing lens group with positive optical power, a third fixed lens group with positive optical power, and a flat glass are arranged in sequence from the object side to the image side along the optical axis;

[0006] The first fixed lens group includes a first lens with negative optical power, a second lens with positive optical power and a third lens with positive optical power, and the first lens and the second lens are cemented together to form a first cemented lens;

[0007] The variable power lens group comprises a fourth lens with negative optical power, a fifth lens with negative optical power and a sixth lens with positive optical power, and the fifth lens and the sixth lens are cemented together to form a second cemented lens;

[0008] The second fixed lens group includes a seventh lens with positive focal power, an eighth lens with negative focal power, a ninth lens with positive focal power, a tenth lens with negative focal power, an eleventh lens with positive focal power, a twelfth lens with negative focal power, and a thirteenth lens with positive focal power, at least two of the eighth lens, the ninth lens, and the tenth lens are cemented to form a third cemented lens, and at least two of the eleventh lens, the twelfth lens, and the thirteenth lens are cemented to form a fourth cemented lens;

[0009] The focusing lens group includes a fourteenth lens with positive optical power;

[0010] The third fixed lens group includes a fifteenth lens having optical power.

[0011] Optionally, the relationship between the focal length F1 of the first fixed lens group, the focal length F2 of the variable power lens group, the focal length F3 of the second fixed lens group, the focal length F4 of the focusing lens group, the focal length F5 of the third fixed lens group and the focal length FW of the wide-angle end of the zoom lens satisfies:

[0012] 5.564≤F1 / FW≤5.885;-1.894≤F2 / FW≤-1.763;2.894≤F3 / FW≤3.128;

[0013] 1.776≤F4 / FW≤2.041;-24.956≤F5 / FW≤13.336.

[0014] Optionally, the object side surface of the first lens is convex, and the image side surface is concave, the object side surface of the second lens is convex, and the image side surface is concave, the object side surface of the third lens is convex, and the image side surface is concave; the object side surface of the fourth lens is concave, and the image side surface is concave, the object side surface of the fifth lens is concave, and the image side surface is concave, the object side surface of the sixth lens is convex, and the image side surface is convex; the object side surface of the seventh lens is convex, and the image side surface is convex, and the object side surface of the eighth lens is The object side surface of the ninth lens is convex, and the image side surface is convex. The object side surface of the tenth lens is concave, and the image side surface is concave. The object side surface of the eleventh lens is convex, and the image side surface is convex. The object side surface of the twelfth lens is concave, and the image side surface is concave. The object side surface of the thirteenth lens is convex, and the image side surface is convex. The object side surface of the fourteenth lens is convex, and the image side surface is convex. The object side surface of the fifteenth lens is convex, and the image side surface is concave.

[0015] Optionally, the eighth lens, the ninth lens and the tenth lens are cemented together, and the eleventh lens, the twelfth lens and the thirteenth lens are cemented together.

[0016] Optionally, the ninth lens and the tenth lens are cemented together, and the eleventh lens, the twelfth lens and the thirteenth lens are cemented together.

[0017] Optionally, the eighth lens, the ninth lens and the tenth lens are cemented together, and the eleventh lens and the twelfth lens are cemented together.

[0018] Optionally, the focal lengths F8-9-10 of the eighth lens, the ninth lens and the tenth lens and the focal length FG3 of the second fixed lens group satisfy:

[0019] -1.603≤F8-9-10 / FG3≤-1.454;

[0020] The focal lengths F11-12-13 of the eleventh lens, the twelfth lens and the thirteenth lens and the focal length FG3 of the second fixed lens group satisfy:

[0021] -32.666≤F11-12-13 / FG3≤2.501.

[0022] Optionally, the aperture FNO of the zoom lens is ≤1.5.

[0023] Optionally, the refractive index nd7 and the Abbe number vd7 of the seventh lens in the second fixed lens group satisfy:

[0024] 1.762≤nd7≤2.005;19.325≤vd7≤25.556;

[0025] The refractive index nd14 and the Abbe number vd14 of the fourteenth lens in the focusing lens group satisfy:

[0026] 1.776≤nd14≤2.051;26.942≤vd14≤37.836.

[0027] Optionally, the total length TTL of the zoom lens and the maximum moving distance S2 of the variable magnification lens group satisfy:

[0028] 3.387≤TTL / S2≤3.653.

[0029] Optionally, the seventh lens is a glass aspherical lens, and the first to sixth lenses, and the eighth to fifteenth lenses are glass spherical lenses.

[0030] Optionally, the moving distance S2 of the zoom lens group and the moving distance S4 of the focus lens group satisfy:

[0031] 27.604≤S2 / S4≤73.811.

[0032] According to the zoom lens provided by the embodiment of the present invention, the zoom lens comprises: a first fixed lens group with positive optical power, a variator lens group with negative optical power, an aperture, a second fixed lens group with positive optical power, a focusing lens group with positive optical power, a third fixed lens group with positive optical power and a flat glass are arranged in sequence along the optical axis from the object side to the image side; the first fixed lens group comprises a first lens with negative optical power, a second lens with positive optical power and a third lens with positive optical power, and the first lens and the second lens are cemented to form a first cemented lens; the variator lens group comprises a fourth lens with negative optical power, a fifth lens with negative optical power and a sixth lens with positive optical power, and the third lens with positive optical power is a first fixed lens group ... The fifth lens and the sixth lens are glued together to form a second glued lens; the second fixed lens group includes a seventh lens with positive focal power, an eighth lens with negative focal power, a ninth lens with positive focal power, a tenth lens with negative focal power, an eleventh lens with positive focal power, a twelfth lens with negative focal power and a thirteenth lens with positive focal power; at least two lenses among the eighth lens, the ninth lens and the tenth lens are glued together to form a third glued lens; at least two lenses among the eleventh lens, the twelfth lens and the thirteenth lens are glued together to form a fourth glued lens; the focusing lens group includes a fourteenth lens with positive focal power; and the third fixed lens group includes a fifteenth lens with focal power. The zoom lens has the characteristics of large aperture, small distortion, long focal length and high-definition imaging, and can meet the use requirements in the 436nm-850nm band under a 1 / 1.2″ target surface.

[0033] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] 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.

[0035] Figure 1 is a schematic structural diagram of the wide-angle end of the zoom lens provided in the first embodiment of the present invention;

[0036] Figure 2 is a schematic structural diagram of the telephoto end of the zoom lens provided in the first embodiment of the present invention;

[0037] Figure 3 is a vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in the first embodiment of the present invention;

[0038] Figure 4is a vertical axis chromatic aberration curve at the telephoto end of the zoom lens proposed in the first embodiment of the present invention;

[0039] Figure 5 is a light fan diagram of the wide-angle end of the zoom lens provided in the first embodiment of the present invention;

[0040] Figure 6 is a light fan diagram of the light rays at the telephoto end of the zoom lens proposed in the first embodiment of the present invention;

[0041] Figure 7 is an axial aberration curve at the wide-angle end of the zoom lens provided in the first embodiment of the present invention;

[0042] Figure 8 is an axial aberration curve at the telephoto end of the zoom lens proposed in Embodiment 1 of the present invention;

[0043] Fig. 9 is a schematic structural diagram of the wide-angle end of the zoom lens provided in the second embodiment of the present invention;

[0044] Fig.10 is a schematic structural diagram of the telephoto end of the zoom lens provided in the second embodiment of the present invention;

[0045] Fig.11 is a vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in the second embodiment of the present invention;

[0046] Fig.12 is a vertical axis chromatic aberration curve at the telephoto end of the zoom lens proposed in the second embodiment of the present invention;

[0047] Fig.13 is a light fan diagram of the wide-angle end of the zoom lens proposed in the second embodiment of the present invention;

[0048] Fig.14 is a light fan diagram of the light rays at the telephoto end of the zoom lens proposed in the second embodiment of the present invention;

[0049] Fig.15 is an axial aberration curve at the wide-angle end of the zoom lens proposed in Embodiment 2 of the present invention;

[0050] Fig.16 is an axial aberration curve at the telephoto end of the zoom lens proposed in Embodiment 2 of the present invention;

[0051] Fig.17 is a schematic structural diagram of the wide-angle end of the zoom lens provided in Embodiment 3 of the present invention;

[0052] Fig.18 is a schematic structural diagram of the telephoto end of the zoom lens provided in Embodiment 3 of the present invention;

[0053] Fig.19is a vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in Embodiment 3 of the present invention;

[0054] Fig. 20 is a vertical axis chromatic aberration curve at the telephoto end of the zoom lens proposed in the third embodiment of the present invention;

[0055] Fig.21 is a light fan diagram of the wide-angle end of the zoom lens proposed in the third embodiment of the present invention;

[0056] Fig. 22 is a light fan diagram of the light at the telephoto end of the zoom lens proposed in the third embodiment of the present invention;

[0057] Fig.23 is an axial aberration curve at the wide-angle end of the zoom lens proposed in Embodiment 3 of the present invention;

[0058] Fig.24 This is the axial aberration curve at the telephoto end of the zoom lens proposed in the third embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 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 should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the specification 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 data 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 that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0061] Figure 1 , Fig. 9 and Fig.17 A schematic diagram of the structure of the zoom lens at the wide-angle end provided by various embodiments of the present invention, Figure 2 , Fig.10 and Fig.18 Schematic diagram of the structure of the zoom lens at the telephoto end provided by various embodiments of the present invention. Figure 1 , Figure 2 , Fig. 9 , Fig.10 , Fig.17 and Fig.18 As shown, the zoom lens provided by the embodiment of the present invention comprises: a first fixed lens group G1 with positive focal power, a zoom lens group G2 with negative focal power, an aperture STO, a second fixed lens group G3 with positive focal power, a focusing lens group G4 with positive focal power, a third fixed lens group G5 with positive focal power and a flat glass PL are arranged in sequence along the optical axis from the object side to the image side; the first fixed lens group G1 comprises a first lens L1 with negative focal power, a second lens L2 with positive focal power and a third lens L3 with positive focal power, and the first lens L1 and the second lens L2 are cemented to form a first cemented lens; the zoom lens group G2 comprises a fourth lens L4 with negative focal power, a fifth lens L5 with negative focal power and a sixth lens L6 with positive focal power, and the fifth lens L5 and the sixth lens L6 are The second fixed lens group G3 includes a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with negative optical power, an eleventh lens L11 with positive optical power, a twelfth lens L12 with negative optical power and a thirteenth lens L13 with positive optical power, at least two of the eighth lens L8, the ninth lens L9 and the tenth lens L10 are cemented to form a third cemented lens, and at least two of the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are cemented to form a fourth cemented lens; the focusing lens group G4 includes a fourteenth lens L14 with positive optical power; and the third fixed lens group G5 includes a fifteenth lens L15 with optical power.

[0062] It can be understood that by setting the first fixed lens group G1, the magnification lens group G2, the second fixed lens group G3, the focusing lens group G4 and the third fixed lens group G5, the positions of the magnification lens group G2 and the focusing lens group G4 on the optical axis are changed, so that the zoom lens can be switched between the wide-angle end and the telephoto end, wherein the zoom lens is located at the wide-angle end when the focal length is the shortest, and the zoom lens is located at the telephoto end when the focal length is the 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.

[0063] The use of the first fixed lens group G1 with positive focal length and the variable magnification lens group G2 with negative focal length at the front end of the aperture STO 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 use requirements under different conditions. In addition, the cemented lens in the first fixed lens group G1 and the variable magnification lens group G2 can correct the high-level chromatic aberration and aberration of the lens, control the aberration balance of each lens group, ensure that no serious aberration is generated when the light enters the structure after the aperture STO, and improve the imaging quality of the zoom lens.

[0064] The second fixed lens group G3 and the focus lens group G4 after the aperture STO can correct the aberration at the rear end of the lens, and cooperate with the lens group at the front end of the aperture STO to stabilize the imaging quality of the zoom lens. The third fixed lens group G5 can reduce the angle of incidence of light so that the light is smoothly incident on the image plane. In addition, controlling the aperture diameter of the lens at different focal lengths to be the same can structurally reduce the aperture range, ensure that the movable group of the lens has a longer travel distance, achieve a higher imaging magnification or reduce the volume, and meet the use requirements under different conditions.

[0065] Furthermore, by matching the focal power of the five lens groups to positive-negative-positive-positive-positive or negative, and reasonably allocating the focal power of each group and the focal power of the components within the group, the light passes through the lens more smoothly, and the influence of high-level aberrations on the image quality is corrected to a great extent. The lens effectively achieves small distortion and high-definition imaging, and also ensures that the lens has a relatively compact total length. This zoom lens comprehensively takes into account the characteristics of zoom, large aperture, low distortion and compact structure.

[0066] Optionally, the relationship between the focal length F1 of the first fixed lens group G1, the focal length F2 of the zoom lens group G2, the focal length F3 of the second fixed lens group G3, the focal length F4 of the focus lens group G4, the focal length F5 of the third fixed lens group G5 and the focal length FW of the zoom lens at the wide angle end satisfies:

[0067] 5.564≤F1 / FW≤5.885;-1.894≤F2 / FW≤-1.763;2.894≤F3 / FW≤3.128;

[0068] 1.776≤F4 / FW≤2.041; -24.956≤F5 / FW≤13.336. This lens matching method can achieve a reasonable combination of optical power, allowing light to pass through the lens more smoothly, and to a large extent correct the impact of high-level aberrations on imaging quality.

[0069] Optionally, refer to Figure 1 , Figure 2 , Fig. 9 , Fig.10 , Fig.17 and Fig.18As shown, the object-side surface of the first lens L1 is convex, and the image-side surface is concave, the object-side surface of the second lens L2 is convex, and the image-side surface is concave, the object-side surface of the third lens L3 is convex, and the image-side surface is concave; the object-side surface of the fourth lens L4 is concave, and the image-side surface is concave, the object-side surface of the fifth lens L5 is concave, and the image-side surface is concave, the object-side surface of the sixth lens L6 is convex, and the image-side surface is convex; the object-side surface of the seventh lens L7 is convex, and the image-side surface is convex, and the object-side surface of the eighth lens L8 is concave, The image side surface is concave, the object side surface of the ninth lens L9 is convex, and the image side surface is convex, the object side surface of the tenth lens L10 is concave, and the image side surface is concave, the object side surface of the eleventh lens L11 is convex, and the image side surface is convex, the object side surface of the twelfth lens L12 is concave, and the image side surface is concave, the object side surface of the thirteenth lens L13 is convex, and the image side surface is convex; the object side surface of the fourteenth lens L14 is convex, and the image side surface is convex, and the object side surface of the fifteenth lens L15 is convex, and the image side surface is concave.

[0070] Among them, the first lens L1 is a convex-concave negative lens, which can allow more light to enter the zoom lens, the second lens L2 is a convex-concave positive lens, and the third lens L3 is a convex-concave positive lens, and the second lens L2 and the third lens L3 are glued together to correct the direction of light entering the zoom lens.

[0071] The fourth lens L4 is a concave-concave negative lens, the fifth lens L5 is a concave-concave negative lens, and the sixth lens L6 is a convex-convex positive lens, which can further adjust the direction of light entering the zoom lens. The negative lens can diffuse the light, and the positive lens can focus the light.

[0072] The seventh lens L7 is a convex-convex positive lens, the eighth lens L8 is a concave-concave negative lens, the ninth lens L9 is a convex-convex positive lens, the tenth lens L10 is a concave-concave negative lens, the eleventh lens L11 is a convex-convex positive lens, the twelfth lens L12 is a concave-concave negative lens, and the thirteenth lens L13 is a convex-convex positive lens. Among them, at least two lenses of the eighth lens L8, the ninth lens L9 and the tenth lens L10 are glued to form a third glued lens, and at least two lenses of the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are glued to form a fourth glued lens. By using glued lenses, the total length of the lens can be effectively shortened, and the second fixed lens group G3 is immediately behind the aperture STO, and the aperture STO can limit the light of different incident angles so that it can enter the second fixed lens group G3 more concentratedly and smoothly. Therefore, using two glued lens groups on the second fixed lens group G3 can well correct the chromatic aberration and high-order aberrations generated by the front lens group, and improve the imaging quality of the overall lens of the system.

[0073] The fourteenth lens L14 is a convex-convex positive lens, and the fifteenth lens L15 is a convex-concave lens. During the zooming process of the zoom lens, the focus lens group G4 will move according to the position change of the zoom lens group G2 so that the system can be in a focusing state at different magnifications. Therefore, a fixed lens group G5 behind the focus lens G4 can greatly optimize the chromatic aberration and higher-order aberrations at different magnification focus positions. Reduce the exit angle of the light, make it smooth and stable incident image plane, and improve the stability of lens imaging.

[0074] Optionally, refer to Figure 1 and Figure 2 As shown, the eighth lens L8, the ninth lens L9 and the tenth lens L10 are cemented together, and the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are cemented together. Using two cemented lens groups on the second fixed lens group G3 can well correct the chromatic aberration and high-order aberration generated by the front lens group, and improve the imaging quality of the overall lens of the system.

[0075] Optionally, refer to Fig. 9 and Fig.10 As shown, the ninth lens L9 and the tenth lens L10 are cemented together, and the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are cemented together. Using two cemented lens groups on the second fixed lens group G3 can well correct the chromatic aberration and high-order aberration generated by the front lens group, and improve the imaging quality of the overall lens of the system.

[0076] Optionally, refer to Fig.17 and Fig.18 As shown, the eighth lens L8, the ninth lens L9 and the tenth lens L10 are cemented, and the eleventh lens L11 and the twelfth lens L12 are cemented. Using two cemented lens groups on the second fixed lens group G3 can well correct the chromatic aberration and high-order aberration generated by the front lens group, and improve the imaging quality of the overall lens of the system.

[0077] Optionally, the focal lengths F8-9-10 of the eighth lens L8, the ninth lens L9 and the tenth lens L10 and the focal length FG3 of the second fixed lens group G3 satisfy: -1.603≤F8-9-10 / FG3≤-1.454; the focal lengths F11-12-13 of the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 and the focal length FG3 of the second fixed lens group G3 satisfy: -32.666≤F11-12-13 / FG3≤2.501. Among them, the focal power and focal length of each lens in the second fixed lens group G3 are reasonably allocated, so that the light passes through the lens more concentratedly and smoothly, and the chromatic aberration and high-order aberration generated by the front lens group are corrected to a great extent, and the imaging quality and brightness of the overall lens of the system are improved. F8-9-10 is the combined focal length of the eighth lens L8, the ninth lens L9 and the tenth lens L10, and F11-12-13 is the combined focal length of the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13.

[0078] Optionally, the aperture FNO of the zoom lens is ≤1.5. The aperture position of the zoom lens remains consistent relative to the image plane position at different focal lengths, and the aperture diameter is the same at different focal lengths.

[0079] Optionally, the refractive index nd7 and Abbe number vd7 of the seventh lens L7 in the second fixed lens group G3 satisfy: 1.762≤nd7≤2.005; 19.325≤vd7≤25.556; the refractive index nd14 and Abbe number vd14 of the fourteenth lens L14 in the focusing lens group G4 satisfy: 1.776≤nd14≤2.051; 26.942≤vd14≤37.836. Among them, the correction of chromatic aberration and higher-order aberration of the zoom lens mainly depends on the cemented lens group in the second fixed lens group G3 and the focusing lens group G4, so the material selection of the seventh lens L7, the first lens of the three-cemented lens in the second fixed lens group G3, and the fourteenth lens L14, the first lens of the double-cemented lens in the focusing lens group G4, is very important. The seventh lens L7 and the fourteenth lens L14 are made of materials with high refractive indexes, so that light can be more concentrated into the rear cemented lens, thereby improving the cemented lens's ability to optimize chromatic aberration and higher-order aberrations.

[0080] Optionally, the total length TTL of the zoom lens and the maximum moving distance S2 of the zoom lens group satisfy: 3.387≤TTL / S2≤3.653. The limitation of the zoom lens group G2 and the total length TTL of the lens can compress the lens space and ensure that the required imaging quality and zoom degree are met under the condition of small lens volume.

[0081] Optionally, the seventh lens L7 is a glass aspherical lens, and the first lens L1 to the sixth lens L6, and the eighth lens L8 to the fifteenth lens L15 are glass spherical lenses.

[0082] Compared with aspherical lenses, spherical lenses require fewer optical parameters to be controlled during the production process, are simpler to process, have lower costs, and have more stable optical performance. Aspherical lenses are more capable of correcting high-level images than spherical lenses. In addition, the properties of glass lenses are not sensitive to temperature. Lenses using all-glass lenses perform more uniformly under different temperature conditions and have stable high and low temperature performance, which improves the environmental adaptability of zoom lenses.

[0083] Optionally, the moving distance S2 of the zoom lens group G2 and the moving distance S4 of the focus lens group G4 satisfy: 27.604≤S2 / S4≤73.811. By controlling the moving distance of the focus lens group G4, the volume and movement range of the focus lens group G4 are minimized, and the lens volume is greatly reduced.

[0084] Therefore, by using 14 glass spherical lenses and 1 glass aspherical lens and a certain thickness of flat glass, and by setting the focal length configuration between each group as described above, a zoom lens with a focal length of 15-50mm and an image plane size of 13.1 can be obtained. The zoom lens has the characteristics of large aperture, small distortion, long focal length and high-definition imaging, and can meet the use requirements in the 436nm-850nm band under a 1 / 1.2″ target surface.

[0085] The zoom lens provided by the present invention is described below with reference to specific embodiments 1 to 3.

[0086] The specific parameters of Examples 1 to 3 are shown in Table 1.

[0087] Table 1 Specific parameters of Examples 1 to 3

[0088] Scope of protection Embodiment 1 Embodiment 2 Embodiment 3 Lower limit Upper limit FNO 1.50 1.50 1.50 1.50 1.50 F1 / FW 5.564 5.885 5.737 5.564 5.885 F2 / FW -1.763 -1.894 -1.797 -1.894 -1.763 F3 / FW 3.104 2.894 3.128 2.894 3.128 F4 / FW 1.803 1.776 2.041 1.776 2.041 F5 / FW -24.956 -5.333 13.336 -24.956 13.336 TTL / S2 3.653 3.387 3.557 3.387 3.653 F8-9-10 / FG3 -1.454 -1.569 -1.603 -1.603 -1.454 F11-12-13 / FG3 -32.666 2.501 -4.261 -32.666 2.501 Nd7 2.002 1.762 2.005 1.762 2.005 Nd14 2.051 2.022 1.776 1.776 2.051 Vd7 19.325 25.556 21.000 19.325 25.556 Vd14 26.942 29.060 37.836 26.942 37.836 S2 / S4 68.353 73.811 27.604 27.604 73.811

[0089] The aspheric lens of the present invention satisfies the following formula:

[0090]

[0091] Where Z is the axial distance from the curved surface at a position perpendicular to the optical axis at a height r to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a10, a12, a14, a16 are the high-order aspheric coefficients of the corresponding aspheric surface of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order, a i r i The combination becomes the high-order terms corresponding to the aspherical surface.

[0092] Embodiment 1

[0093] Figure 1is a schematic structural diagram of the wide-angle end of the zoom lens provided in the first embodiment of the present invention; Figure 2 : is a schematic diagram of the structure of the telephoto end of the zoom lens proposed in the first embodiment of the present invention. In this embodiment, in the second fixed lens group G3, the eighth lens L8, the ninth lens L9 and the tenth lens L10 are cemented together, and the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are cemented together. The relevant parameters of the zoom lens can be referred to as shown in Tables 1, 2, 3 and 4.

[0094] The design values ​​of each lens in Example 1 are shown in Table 2.

[0095] Table 2 Design values ​​of the first to fifteenth lenses in the zoom lens of Example 1

[0096]

[0097]

[0098] The surface numbers S1-S27 in Table 2 are numbered according to the surface order of each lens, "STO" represents the aperture of the lens; IMA represents the image plane; the radius of curvature represents the curvature of the corresponding lens surface, a positive value represents that the surface is bent toward the image plane, and a negative value represents that the surface is bent toward the object plane, wherein "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air and the refractive index is 1.

[0099] Table 3 Parameters of the zoom lens at the wide-angle end and the telephoto end in Example 1

[0100] Wide-angle end Telephoto end Zoom interval 1(mm) 1.308 35.525 Zoom interval 2(mm) 34.946 0.729 Zoom interval 3(mm) 10.006 9.510 Zoom interval 4(mm) 4.188 4.688 Image size(mm) Φ13.10 Φ13.10 Focal length(mm) 15 50 Wavelength(nm) 436～850 436～850 Total optical length (mm) 125 125

[0101] Table 4 Aspheric coefficients of the seventh lens in Example 1

[0102]

[0103] Figure 3 is a vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in the first embodiment of the present invention; Figure 4 This is the vertical axis chromatic aberration curve of the zoom lens at the telephoto end proposed in the first embodiment of the present invention. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum image height. The main wavelength uses 546.07nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 3 , Figure 4It can be seen that the vertical chromatic aberration of different wavelengths (the blue line represents 436nm, the green line represents 487nm, the red line represents 546nm, the yellow line represents 587nm, and the purple line represents 656nm) is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different focal lengths is well controlled and can meet the application requirements under normal conditions.

[0104] The ray fan diagram is one of the evaluation methods commonly used by optical designers. Figure 5 is a light fan diagram of the wide-angle end of the zoom lens provided in the first embodiment of the present invention; Figure 6 It is a light fan diagram of the telephoto end of the zoom lens proposed in Example 1 of the present invention. In a single diagram, the horizontal axis is the normalized light beam diameter, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, at which time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 5 , Figure 6 It can be seen that the wavelengths of this zoom lens at different focal lengths and fields of view (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0105] Figure 7 is the axial aberration curve at the wide-angle end of the zoom lens proposed in the first embodiment of the present invention, Figure 8 It is the axial aberration curve of the telephoto end of the zoom lens proposed in the first embodiment of the present invention. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Figure 7 , Figure 8 It can be seen that the axial aberrations of different wavelengths (blue represents 436nm, green represents 487nm, red represents 546nm, yellow represents 587nm, purple represents 656nm, and light blue represents 850nm) and the normalized aperture of 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial chromatic aberration of the zoom lens at different focal lengths is well controlled and meets the usage requirements.

[0106] Embodiment 2

[0107] Fig. 9 is a schematic structural diagram of the wide-angle end of the zoom lens provided in the second embodiment of the present invention; Fig.10 : is a schematic diagram of the structure of the telephoto end of the zoom lens proposed in the second embodiment of the present invention. In this embodiment, in the second fixed lens group G3, the ninth lens L9 and the tenth lens L10 are cemented together, and the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are cemented together. The relevant parameters of the zoom lens can be referred to as shown in Table 1, Table 5, Table 6 and Table 7.

[0108] Table 5 Design values ​​of the first to fifteenth lenses in the zoom lens of Example 2

[0109]

[0110]

[0111] The surface numbers S1-S28 in Table 5 are numbered according to the surface order of each lens, "STO" represents the aperture of the lens; 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 bent toward the image plane, and a negative value represents that the surface is bent toward the object plane, wherein "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air and the refractive index is 1.

[0112] Table 6 Parameters of the zoom lens at the wide-angle end and the telephoto end in Example 2

[0113] Wide-angle end Telephoto end Zoom interval 1(mm) 1.424 38.330 Zoom interval 2(mm) 37.685 0.779 Zoom interval 3(mm) 11.741 11.241 Zoom interval 4(mm) 3.353 3.853 Image size(mm) Φ13.10 Φ13.10 Focal length(mm) 15 50 Wavelength(nm) 436～850 436～850 Total optical length (mm) 125 125

[0114] Table 7 Aspheric coefficients of the seventh lens in Example 2

[0115]

[0116] Fig.11 is a vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in the second embodiment of the present invention; Fig.12 This is the vertical axis chromatic aberration curve of the zoom lens at the telephoto end proposed in the second embodiment of the present invention. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum image height. The main wavelength uses 546.07nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Fig.11 , Fig.12 It can be seen that the vertical chromatic aberration of different wavelengths (the blue line represents 436nm, the green line represents 487nm, the red line represents 546nm, the yellow line represents 587nm, and the purple line represents 656nm) is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different focal lengths is well controlled and can meet the application requirements under normal conditions.

[0117] The ray fan diagram is one of the evaluation methods commonly used by optical designers. Fig.13 is a light fan diagram of the wide-angle end of the zoom lens proposed in the second embodiment of the present invention; Fig.14 It is the light fan diagram of the telephoto end of the zoom lens proposed in Example 2 of the present invention. In a single diagram, the horizontal axis is the normalized light beam diameter, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, at which time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.13 , Fig.14 It can be seen that the wavelengths of this zoom lens at different focal lengths and fields of view (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0118] Fig.15 is the axial aberration curve at the wide-angle end of the zoom lens proposed in the second embodiment of the present invention, Fig.16 It is the axial aberration curve of the telephoto end of the zoom lens proposed in the second embodiment of the present invention. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Fig.15 , Fig.16 It can be seen that the axial aberrations of different wavelengths (blue represents 436nm, green represents 487nm, red represents 546nm, yellow represents 587nm, purple represents 656nm, and light blue represents 850nm) and the normalized aperture of 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial chromatic aberration of the zoom lens at different focal lengths is well controlled and meets the usage requirements.

[0119] Embodiment 3

[0120] Fig.17 is a schematic structural diagram of the wide-angle end of the zoom lens provided in Embodiment 3 of the present invention; Fig.18 : is a schematic diagram of the structure of the telephoto end of the zoom lens proposed in the third embodiment of the present invention. In this embodiment, in the second fixed lens group G3, the eighth lens L8, the ninth lens L9 and the tenth lens L10 are cemented together, and the twelfth lens L12 and the thirteenth lens L13 are cemented together. The relevant parameters of the zoom lens can be referred to as shown in Table 1, Table 8, Table 9 and Table 10.

[0121] Table 8 Design values ​​of the first to fifteenth lenses in the zoom lens of Example 3

[0122]

[0123]

[0124] The surface numbers S1-S28 in Table 8 are numbered according to the surface order of each lens, "STO" represents the aperture of the lens; IMA represents the image plane; the radius of curvature represents the curvature of the corresponding lens surface, a positive value represents that the surface is bent toward the image plane, and a negative value represents that the surface is bent toward the object plane, wherein "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air and the refractive index is 1.

[0125] Table 9 Parameters of the zoom lens at the wide-angle end and the telephoto end in Example 3

[0126] Wide-angle end Telephoto end Zoom interval 1(mm) 1.292 36.437 Zoom interval 2(mm) 35.824 0.679 Zoom interval 3(mm) 10.686 9.413 Zoom interval 4(mm) 3.256 4.529 Image size(mm) Φ13.10 Φ13.10 Focal length(mm) 15 50 Wavelength(nm) 436～850 436～850 Total optical length (mm) 125 125

[0127] Table 10 Aspheric coefficients of the seventh lens in Example 3

[0128]

[0129]

[0130] Fig.19 is a vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in Embodiment 3 of the present invention; Fig. 20 This is the vertical axis chromatic aberration curve of the zoom lens at the telephoto end proposed in the third embodiment of the present invention. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum image height. The main wavelength uses 546.07nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Fig.19 , Fig. 20 It can be seen that the vertical chromatic aberration of different wavelengths (the blue line represents 436nm, the green line represents 487nm, the red line represents 546nm, the yellow line represents 587nm, and the purple line represents 656nm) is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at different focal lengths is well controlled and can meet the application requirements under normal conditions.

[0131] The ray fan diagram is one of the evaluation methods commonly used by optical designers. Fig.21 is a light fan diagram of the wide-angle end of the zoom lens proposed in the third embodiment of the present invention; Fig. 22It is the light fan diagram of the telephoto end of the zoom lens proposed in Example 3 of the present invention. In a single diagram, the horizontal axis is the normalized light beam diameter, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, at which time all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.21 , Fig. 22 It can be seen that the wavelengths of this zoom lens at different focal lengths and fields of view (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) are all close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction of chromatic aberration, meeting the use requirements of this zoom lens.

[0132] Fig.23 is the axial aberration curve at the wide-angle end of the zoom lens proposed in Embodiment 3 of the present invention, Fig.24 This is the axial aberration curve of the telephoto end of the zoom lens proposed in the third embodiment of the present invention. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis direction represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Fig.23 , Fig.24 It can be seen that the axial aberrations of different wavelengths (blue represents 436nm, green represents 487nm, red represents 546nm, yellow represents 587nm, purple represents 656nm, and light blue represents 850nm) and the normalized aperture of 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial chromatic aberration of the zoom lens at different focal lengths is well controlled and meets the usage requirements.

[0133] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A zoom lens, characterized in that: include: Arranged in sequence from the object side to the image side along the optical axis are a first fixed lens group with positive focal power, a zoom lens group with negative focal power, an aperture, a second fixed lens group with positive focal power, a focusing lens group with positive focal power, a third fixed lens group with positive focal power, and a flat glass; The first fixed lens group includes a first lens with negative optical power, a second lens with positive optical power and a third lens with positive optical power, and the first lens and the second lens are cemented together to form a first cemented lens; The variable power lens group comprises a fourth lens with negative optical power, a fifth lens with negative optical power and a sixth lens with positive optical power, and the fifth lens and the sixth lens are cemented together to form a second cemented lens; The second fixed lens group includes a seventh lens with positive focal power, an eighth lens with negative focal power, a ninth lens with positive focal power, a tenth lens with negative focal power, an eleventh lens with positive focal power, a twelfth lens with negative focal power, and a thirteenth lens with positive focal power, at least two of the eighth lens, the ninth lens, and the tenth lens are cemented to form a third cemented lens, and at least two of the eleventh lens, the twelfth lens, and the thirteenth lens are cemented to form a fourth cemented lens; The focusing lens group includes a fourteenth lens with positive optical power; The third fixed lens group includes a fifteenth lens having optical power.

2. The zoom lens according to claim 1, wherein: The relationship between the focal length F1 of the first fixed lens group, the focal length F2 of the variable power lens group, the focal length F3 of the second fixed lens group, the focal length F4 of the focus lens group, the focal length F5 of the third fixed lens group and the focal length FW of the zoom lens at the wide angle end satisfies: 5.564≤F1 / FW≤5.885;-1.894≤F2 / FW≤-1.763;2.894≤F3 / FW≤3.128; 1.776≤F4 / FW≤2.041;-24.956≤F5 / FW≤13.

336.

3. The zoom lens according to claim 1, wherein: The object side surface of the first lens is convex, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is concave; the object side surface of the third lens is convex, and the image side surface is concave; the object side surface of the fourth lens is concave, and the image side surface is concave; the object side surface of the fifth lens is concave, and the image side surface is concave; the object side surface of the sixth lens is convex, and the image side surface is convex; the object side surface of the seventh lens is convex, and the image side surface is convex; the object side surface of the eighth lens is concave, and the image side surface is concave; the object side surface of the ninth lens is convex, and the image side surface is convex; the object side surface of the tenth lens is concave, and the image side surface is concave; the object side surface of the eleventh lens is convex, and the image side surface is convex; the object side surface of the twelfth lens is concave, and the image side surface is concave; the object side surface of the thirteenth lens is convex, and the image side surface is convex; the object side surface of the fourteenth lens is convex, and the image side surface is convex; the object side surface of the fifteenth lens is convex, and the image side surface is concave.

4. The zoom lens according to claim 1, wherein: The eighth lens, the ninth lens and the tenth lens are cemented together, and the eleventh lens, the twelfth lens and the thirteenth lens are cemented together.

5. The zoom lens according to claim 1, wherein: The ninth lens and the tenth lens are cemented together, and the eleventh lens, the twelfth lens and the thirteenth lens are cemented together.

6. The zoom lens according to claim 1, wherein: The eighth lens, the ninth lens and the tenth lens are cemented together, and the eleventh lens and the twelfth lens are cemented together.

7. The zoom lens according to claim 1, wherein: The focal lengths F8-9-10 of the eighth lens, the ninth lens and the tenth lens and the focal length FG3 of the second fixed lens group satisfy: -1.603≤F8-9-10 / FG3≤-1.454; The focal lengths F11-12-13 of the eleventh lens, the twelfth lens and the thirteenth lens and the focal length FG3 of the second fixed lens group satisfy: -32.666≤F11-12-13 / FG3≤2.

501.

8. The zoom lens according to claim 1, wherein: The aperture FNO of the zoom lens is ≤1.

5.

9. The zoom lens according to claim 1, wherein: The refractive index nd7 and the Abbe number vd7 of the seventh lens in the second fixed lens group satisfy: 1.762≤nd7≤2.005;19.325≤vd7≤25.556; The refractive index nd14 and the Abbe number vd14 of the fourteenth lens in the focusing lens group satisfy: 1.776≤nd14≤2.051;26.942≤vd14≤37.

836.

10. The zoom lens according to claim 1, wherein: The total length TTL of the zoom lens and the maximum moving distance S2 of the zoom lens group satisfy: 3.387≤TTL / S2≤3.

653.

11. The zoom lens according to claim 1, wherein: The seventh lens is a glass aspherical lens, and the first to sixth lenses, and the eighth to fifteenth lenses are glass spherical lenses.

12. The zoom lens according to claim 1, wherein: The moving distance S2 of the zoom lens group and the moving distance S4 of the focus lens group satisfy: 27.604≤S2 / S4≤73.811.

Images