Zoom lens

Abstract

The utility model 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 utility model relates to the technical field of optical lenses, in particular to a zoom lens. Background Art

[0002] ITS (Intelligent Transportation System) lenses are specifically designed for use with image sensors. They typically feature high resolution, low distortion, and high contrast, providing clear, accurate, and high-quality images. Their design considers optical properties, mechanical structure, and electronic interfaces, effectively adapting to diverse and complex environments.

[0003] Currently, most of the commonly used ITS lenses 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. However, 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. Utility Model Content

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

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

[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 zoom lens assembly includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power, wherein 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 having positive optical power, an eighth lens having negative optical power, a ninth lens having positive optical power, a tenth lens having negative optical power, an eleventh lens having positive optical power, a twelfth lens having negative optical power, and a thirteenth lens having positive optical power; at least two of the eighth lens, the ninth lens, and the tenth lens are cemented together to form a third cemented lens; and at least two of the eleventh lens, the twelfth lens, and the thirteenth lens are cemented together 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 variator 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:

[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 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.

[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 the following conditions:

[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 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 zoom 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 an embodiment of the present invention, the zoom lens includes: 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, arranged in sequence along the optical axis from the object side to the image side; the first fixed lens group includes a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power, the first lens and the second lens being cemented together to form a first cemented lens; the variator lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power. The fifth and sixth lenses are cemented together to form a second cemented lens. The second fixed lens group includes a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with positive optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, a twelfth lens with negative optical power, and a thirteenth lens with positive optical power. At least two of the eighth, ninth, and tenth lenses are cemented together to form a third cemented lens. At least two of the eleventh, twelfth, and thirteenth lenses are cemented together 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 with optical power. This zoom lens features a large aperture, minimal distortion, a long focal length, and high-definition imaging, meeting the requirements of use in the 436nm-850nm wavelength range on a 1 / 1.2" target surface.

[0033] 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 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 paying any creative work.

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

[0036] Figure 2 1 is a schematic structural diagram of the telephoto end of the zoom lens proposed in the first embodiment of the present invention;

[0037] Figure 3 is the vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in Example 1 of the present utility model;

[0038] Figure 4 is the vertical axis chromatic aberration curve at the telephoto end of the zoom lens proposed in Example 1 of the present utility model;

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

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

[0041] Figure 7 is the axial aberration curve at the wide-angle end of the zoom lens proposed in Example 1 of the present utility model;

[0042] Figure 8 is the axial aberration curve at the telephoto end of the zoom lens proposed in Example 1 of the present utility model;

[0043] Figure 9 This is a schematic structural diagram of the wide-angle end of the zoom lens proposed in the second embodiment of the present invention;

[0044] Figure 10 This is a schematic structural diagram of the telephoto end of the zoom lens proposed in the second embodiment of the present invention;

[0045] Figure 11 is the vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in Example 2 of the present utility model;

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

[0047] Figure 13 This is a ray fan diagram at the wide-angle end of the zoom lens proposed in the second embodiment of the present invention;

[0048] Figure 14 This is a ray fan diagram at the telephoto end of the zoom lens proposed in the second embodiment of the present invention;

[0049] Figure 15 is the axial aberration curve at the wide-angle end of the zoom lens proposed in Example 2 of the present utility model;

[0050] Figure 16 is the axial aberration curve at the telephoto end of the zoom lens proposed in the second embodiment of the present invention;

[0051] Figure 17 This is a schematic structural diagram of the wide-angle end of the zoom lens proposed in the third embodiment of the present invention;

[0052] Figure 18 This is a schematic structural diagram of the telephoto end of the zoom lens proposed in the third embodiment of the present invention;

[0053] Figure 19 is the vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in the third embodiment of the present invention;

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

[0055] Figure 21 This is a ray fan diagram at the wide-angle end of the zoom lens proposed in the third embodiment of the present invention;

[0056] Figure 22 This is a ray fan diagram at the telephoto end of the zoom lens proposed in the third embodiment of the present invention;

[0057] Figure 23 This is the axial aberration curve at the wide-angle end of the zoom lens proposed in the third embodiment of the present invention;

[0058] Figure 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 help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the 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.

[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 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.

[0061] Figure 1 、 Figure 9 and Figure 17 This is 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 、 Figure 10 and Figure 18 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by each embodiment of the present invention. Figure 1 、 Figure 2 、 Figure 9 、 Figure 10 、 Figure 17 and Figure 18 As shown, the zoom lens proposed in an embodiment of the present invention includes: a first fixed lens group G1 with positive optical power, a variator lens group G2 with negative optical power, an aperture STO, a second fixed lens group G3 with positive optical power, a focusing lens group G4 with positive optical power, a third fixed lens group G5 with positive optical power, and a flat glass PL, which are arranged in sequence along the optical axis from the object side to the image side; the first fixed lens group G1 includes a first lens L1 with negative optical power, a second lens L2 with positive optical power, and a third lens L3 with positive optical power, and the first lens L1 and the second lens L2 are cemented to form a first cemented lens; the variator lens group G2 includes a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, and a sixth lens L6 with positive optical power, and the fifth lens L5 and the sixth lens L6 are cemented to form a first cemented lens. The first lens group G1 comprises 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. 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 comprises a fourteenth lens L14 with positive optical power. The third fixed lens group G5 comprises 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, and the zoom lens can be switched between the wide-angle end and the telephoto end. When the focal length is the shortest, the zoom lens is at the wide-angle end, and when the focal length is the longest, the zoom lens is at the telephoto end. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical focal powers, and also has different shapes.

[0063] The use of a positive-power first fixed lens group G1 and a negative-power zoom lens group G2 at the front of the aperture STO ensures a larger light aperture after light passes through it, increasing the zoom lens's F-number to meet the requirements of various usage conditions. Furthermore, the cemented lens within the first fixed lens group G1 and the zoom lens group G2 corrects high-level chromatic aberrations and aberrations, controlling the aberration balance of each lens group. This ensures that light entering the structure behind the aperture STO does not produce significant aberrations, thereby improving the zoom lens's imaging quality.

[0064] The second fixed lens group G3 and the focusing lens group G4 behind the aperture STO correct aberrations at the rear end of the lens. Together with the lens group in front of the aperture STO, they stabilize the zoom lens's imaging quality. The third fixed lens group G5 reduces the angle of incidence of light, ensuring smoother light incidence on the image plane. Furthermore, maintaining the same aperture diameter at different focal lengths reduces the aperture range structurally, ensuring a longer travel distance for the lens' movable group, enabling higher imaging magnification or reducing the lens's size to meet varying usage requirements.

[0065] Furthermore, by combining the optical powers of the five lens groups in a pattern of positive-negative-positive-positive-positive or negative, and rationally distributing the optical power of each group and the optical power of the elements within each group, light passes smoothly through the lens, significantly correcting the effects of higher-order aberrations on image quality. This effectively achieves minimal distortion and high-definition imaging while maintaining a relatively compact overall length. This zoom lens comprehensively balances zoom, large aperture, low distortion, and a compact design.

[0066] Optionally, the relationship between the focal length F1 of the first fixed lens group G1, the focal length F2 of the variator 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 combination achieves a reasonable combination of optical powers, allowing light to pass through the lens more smoothly, and largely correcting the impact of high-level aberrations on image quality.

[0069] Optionally, refer to Figure 1 、 Figure 2 、 Figure 9 、 Figure 10 、 Figure 17 and Figure 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; 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. The second lens L2 and the third lens L3 are cemented together to correct the direction of light entering the zoom lens.

[0071] The fourth lens element L4 is a negative concave-concave lens, the fifth lens element L5 is a negative concave-concave lens, and the sixth lens element L6 is a positive convex-convex lens. These elements further adjust the direction of light entering the zoom lens. The negative lens diffuses the light, while the positive lens focuses it.

[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. At least two of the eighth lens L8, the ninth lens L9, and the tenth lens L10 are cemented together 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 together to form a fourth cemented lens. The use of cemented lenses effectively shortens the overall length of the lens. The second fixed lens group G3 follows immediately behind the aperture STO, which limits light rays of varying incident angles, ensuring they enter the second fixed lens group G3 in a more concentrated and smooth manner. Therefore, the use of two cemented lens groups in the second fixed lens group G3 effectively corrects chromatic aberration and higher-order aberrations produced by the preceding lens group, improving the overall imaging quality 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 zooming, the focus lens group G4 moves according to the position of the variator lens group G2, ensuring that the system maintains a consistent focus state at all magnifications. Therefore, the addition of a fixed lens group G5 behind the focus lens G4 significantly optimizes chromatic aberration and higher-order aberrations at different magnifications and focus positions. This reduces the angle of incidence of light, resulting in a smooth and stable incident image plane, improving the stability of the 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. The use of two cemented lens groups in the second fixed lens group G3 effectively corrects chromatic aberration and higher-order aberrations produced by the front lens group, improving the imaging quality of the entire system.

[0075] Optionally, refer to Figure 9 and Figure 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. The use of two cemented lens groups in the second fixed lens group G3 effectively corrects chromatic aberration and higher-order aberrations produced by the front lens group, improving the imaging quality of the entire system.

[0076] Optionally, refer to Figure 17 and Figure 18 As shown, the eighth lens L8, the ninth lens L9, and the tenth lens L10 are cemented together, and the eleventh lens L11 and the twelfth lens L12 are cemented together. The use of two cemented lens groups in the second fixed lens group G3 can effectively correct chromatic aberration and higher-order aberrations generated by the front lens group, improving the imaging quality of the entire lens system.

[0077] Optionally, the focal lengths F8-9-10 of the eighth lens element L8, the ninth lens element L9, and the tenth lens element L10, together with the focal length FG3 of the second fixed lens group G3, satisfy the following relationship: -1.603 ≤ F8-9-10 / FG3 ≤ -1.454; and the focal lengths F11-12-13 of the eleventh lens element L11, the twelfth lens element L12, and the thirteenth lens element L13, together with the focal length FG3 of the second fixed lens group G3, satisfy the following relationship: -32.666 ≤ F11-12-13 / FG3 ≤ 2.501. The rational allocation of the focal powers and focal lengths of the lenses in the second fixed lens group G3 ensures a more concentrated and smooth passage of light through the lens, significantly correcting chromatic aberration and higher-order aberrations produced by the front lens group and improving the imaging quality and brightness of the overall lens system. 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 position of the aperture of the zoom lens relative to the image plane remains consistent 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 element L7 in the second fixed lens group G3 satisfy the following: 1.762≤nd7≤2.005; 19.325≤vd7≤25.556; and the refractive index nd14 and Abbe number vd14 of the fourteenth lens element L14 in the focusing lens group G4 satisfy the following: 1.776≤nd14≤2.051; 26.942≤vd14≤37.836. The correction of chromatic aberration and higher-order aberrations in this zoom lens depends primarily on the cemented lens groups in the second fixed lens group G3 and the focusing lens group G4. Therefore, the material selection of the seventh lens element L7, the front lens element of the cemented triplet in the second fixed lens group G3, and the fourteenth lens element L14, the front lens element of the cemented doublet in the focusing lens group G4, is crucial. The seventh lens L7 and the fourteenth lens L14 are made of materials with high refractive index, so that light can be more focused 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 travel distance S2 of the zoom lens group satisfy the following relationship: 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, ensuring that the required imaging quality and zoom range are met while maintaining a 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 to aspheric lenses, spherical lenses require fewer optical parameters to control during production, resulting in simpler processing, lower costs, and more stable optical performance. Aspheric lenses are also more capable of correcting high-grade images than spherical lenses. Furthermore, glass lenses are insensitive to temperature, making all-glass lenses more consistent across temperature ranges. This ensures stable performance at both high and low temperatures, improving 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, thereby greatly reducing the lens volume.

[0084] Thus, by using 14 glass spherical lenses, one glass aspherical lens, and a certain thickness of flat glass, and by configuring the focal lengths of the various groups as described above, a zoom lens with a focal length of 15-50mm and an image plane size of 13.1 can be obtained. This zoom lens has the characteristics of a large aperture, low distortion, a long focal length, and high-definition imaging, and can meet the requirements of use in the 436nm-850nm band with a 1 / 1.2" target surface.

[0085] The zoom lens proposed 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 Example 1 Example 2 Example 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 utility model satisfies the following formula:

[0090]

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

[0092] Example 1

[0093] Figure 1This is a schematic structural diagram of the wide-angle end of the zoom lens proposed in the first embodiment of the present invention; Figure 2 This is a schematic diagram of the telephoto end structure of the zoom lens proposed in Example 1 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 this zoom lens can be found 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 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, where "INF" indicates 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 blank 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 the vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in Example 1 of the present utility model; Figure 4 This is the vertical axis chromatic aberration curve at the telephoto end of the zoom lens proposed in Example 1 of the present invention. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 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 at different wavelengths (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) is all controlled within a small range, indicating that the vertical chromatic aberration of this 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 This is a ray fan diagram of the wide-angle end of the zoom lens proposed in the first embodiment of the present invention; Figure 6 This is the ray fan diagram of the telephoto end of the zoom lens proposed in Example 1 of the present invention. The horizontal axis in a single diagram is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this 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 diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 5 、 Figure 6 As can be seen, the zoom lens's curves for each wavelength (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) at various focal lengths and fields of view are all closely aligned with the horizontal axis, indicating that vertical aberration at each wavelength is well corrected. Furthermore, there is no noticeable dispersion in the curves for each color, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[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 This is the axial aberration curve at the telephoto end of the zoom lens proposed in Example 1 of the present invention. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 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 at 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 this zoom lens at different focal lengths is well controlled and meets the requirements of use.

[0106] Example 2

[0107] Figure 9This is a schematic structural diagram of the wide-angle end of the zoom lens proposed in the second embodiment of the present invention; Figure 10 This is a schematic diagram of the telephoto end structure of the zoom lens proposed in Example 2 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. Relevant parameters of this zoom lens can be found in Tables 1, 5, 6, and 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, where "INF" indicates 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 blank 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] Figure 11 is the vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in Example 2 of the present utility model; Figure 12 This is the vertical axis chromatic aberration curve at the telephoto end of the zoom lens proposed in Example 2 of the present invention. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546.07nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 11 、 Figure 12It can be seen that the vertical chromatic aberration at different wavelengths (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) is all controlled within a small range, indicating that the vertical chromatic aberration of this 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. Figure 13 This is a ray fan diagram at the wide-angle end of the zoom lens proposed in the second embodiment of the present invention; Figure 14 This is the ray fan diagram of the telephoto end of the zoom lens proposed in Example 2 of the present invention. The horizontal axis in a single diagram is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this 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 diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 13 、 Figure 14 As can be seen, the zoom lens's curves for each wavelength (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) at various focal lengths and fields of view are all closely aligned with the horizontal axis, indicating that vertical aberration at each wavelength is well corrected. Furthermore, there is no noticeable dispersion in the curves for each color, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0118] Figure 15 is the axial aberration curve at the wide-angle end of the zoom lens proposed in the second embodiment of the present invention, Figure 16 This is the axial aberration curve at the telephoto end of the zoom lens proposed in Example 2 of the present invention. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Figure 15 、 Figure 16 It can be seen that the axial aberrations at 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 this zoom lens at different focal lengths is well controlled and meets the requirements of use.

[0119] Example 3

[0120] Figure 17This is a schematic structural diagram of the wide-angle end of the zoom lens proposed in the third embodiment of the present invention; Figure 18 This is a schematic diagram of the telephoto end structure of the zoom lens proposed in Example 3 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 this zoom lens can be found in Tables 1, 8, 9, and 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 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, where "INF" indicates 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 blank 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] Figure 19 is the vertical axis chromatic aberration curve at the wide-angle end of the zoom lens proposed in the third embodiment of the present invention; Figure 20 This is the vertical axis chromatic aberration curve at the telephoto end of the zoom lens proposed in Example 3 of the present invention. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum image height. The main wavelength is 546.07nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 19 、 Figure 20It can be seen that the vertical chromatic aberration at different wavelengths (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) is all controlled within a small range, indicating that the vertical chromatic aberration of this zoom lens at different focal lengths is well controlled and can meet the application requirements under normal conditions.

[0130] The ray fan diagram is one of the evaluation methods commonly used by optical designers. Figure 21 This is a ray fan diagram at the wide-angle end of the zoom lens proposed in the third embodiment of the present invention; Figure 22 This is the ray fan diagram of the telephoto end of the zoom lens proposed in Example 3 of the present invention. The horizontal axis in a single diagram is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this 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 diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 21 、 Figure 22 As can be seen, the zoom lens's curves for each wavelength (blue line represents 436nm, green line represents 487nm, red line represents 546nm, yellow line represents 587nm, and purple line represents 656nm) at various focal lengths and fields of view are all closely aligned with the horizontal axis, indicating that vertical aberration at each wavelength is well corrected. Furthermore, there is no noticeable dispersion in the curves for each color, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0131] Figure 23 is the axial aberration curve at the wide-angle end of the zoom lens proposed in the third embodiment of the present invention, Figure 24 This is the axial aberration curve at the telephoto end of the zoom lens proposed in Example 3 of the present invention. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Figure 23 、 Figure 24 It can be seen that the axial aberrations at 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 this zoom lens at different focal lengths is well controlled and meets the requirements of use.

[0132] The above specific embodiments do not limit the scope of protection of this utility model. 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 this utility model shall be included within the scope of protection of this utility model.

Claims

1. A zoom lens, characterized in that: include: Arranged in order from the object side to the image side along the optical axis are: a first fixed lens group with positive optical power, a zoom 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 plate 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 zoom lens assembly includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power, wherein 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 having positive optical power, an eighth lens having negative optical power, a ninth lens having positive optical power, a tenth lens having negative optical power, an eleventh lens having positive optical power, a twelfth lens having negative optical power, and a thirteenth lens having positive optical power; at least two of the eighth lens, the ninth lens, and the tenth lens are cemented together to form a third cemented lens; and at least two of the eleventh lens, the twelfth lens, and the thirteenth lens are cemented together 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 variator 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 the following conditions: -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 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 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