Zoom optical system

Abstract

The utility model discloses a zoom optical system, and relates to the technical field of zoom optical systems, the zoom optical system is provided with an object side and an image side which are correspondingly arranged along the direction of an optical axis, the zoom optical system comprises a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group and an image surface which are sequentially arranged from the object side to the image side, the second lens group, the fourth lens group and the fifth lens group are all movably arranged along the optical axis direction, the moving stroke of the second lens group is 26.2 mm, the moving stroke of the fourth lens group is 5.8 mm, the moving stroke of the fifth lens group is 1.07 mm, the second lens group and the fifth lens group are used for zooming, and the fourth lens group is used for focusing. Through the arrangement, the optical distortion range of the zoom optical system can be between-4.04% and 2.94%. Therefore, the optical zoom system which is small in size, small in distortion, short in focusing object distance and confocal at high and low temperatures is obtained.

Description

Technical Field

[0001] The utility model relates to the technical field of zoom optical systems, and particularly relates to a zoom optical system. Background Art

[0002] In the field of video applications (film and broadcast shooting), zoom lenses have been widely used due to their advantages such as clear shooting images, short shooting distances, large shooting angles, and small distortion. With the development of technology, high pixel count, large image sensor format, small distortion, and imaging at close object distances have become requirements for a new generation of video lenses.

[0003] However, currently, the mainstream video zoom lenses on the market have problems such as low clarity, large volume, unclear focusing at close object distances, and small image sensor formats, and are increasingly unable to meet market demands. Summary of the Utility Model

[0004] The main object of the utility model is to propose a zoom optical system, aiming to solve the problems that existing video zoom lenses have low clarity, large volume, unclear focusing at close object distances, and small image sensor formats, and are increasingly unable to meet market demands.

[0005] To achieve the above object, the zoom optical system proposed by the utility model has an object side and an image side arranged corresponding to each other along the optical axis direction. The zoom optical system includes a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and an image plane arranged in sequence from the object side to the image side. The second lens group, the fourth lens group, and the fifth lens group are all movably arranged along the optical axis direction. The moving stroke of the second lens group is 26.2 mm, the moving stroke of the fourth lens group is 5.8 mm, and the moving stroke of the fifth lens group is 1.07 mm. The second lens group and the fifth lens group are used for zooming, and the fourth lens group is used for focusing.

[0006] Wherein, the focal length of the zoom optical system is f, the focal length of the zoom optical system at the wide-angle end is fw, the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the third lens group is f3, the focal length of the fourth lens group is f4, and the focal length of the fifth lens group is f5. The zoom optical system satisfies the following conditions:

[0007] 20.8 mm ≤ f ≤ 59.17 mm; 0.260 ≤ fw / f1 ≤ 0.302; and -1.330 ≤ fw / f2 ≤ -0.983; and 0.867 ≤ fw / f3 ≤ 1.174; and -1.286 ≤ fw / f4 ≤ -0.950; and 0.398 ≤ fw / f5 ≤ 0.539.

[0008] In one embodiment, the optical power of the first lens group is positive. The first 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 arranged in sequence along the optical axis direction. The first lens and the second lens are adhesively connected.

[0009] The focal length of the first lens is f11, the focal length of the second lens is f12, and the focal length of the third lens is f13. Among them, -0.664 ≤ f1 / f11 ≤ -0.573; and 0.729 ≤ f1 / f12 ≤ 0.845; and 0.706 ≤ f1 / f13 ≤ 0.819.

[0010] In one embodiment, the optical power of the second lens group is negative. The second lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power arranged in sequence along the optical axis direction. The fifth lens and the sixth lens are adhesively connected.

[0011] The focal length of the fourth lens is f21, the focal length of the fifth lens is f22, and the focal length of the sixth lens is f23. Among them, 0.664 ≤ f2 / f21 ≤ 0.898; and 0.643 ≤ f2 / f22 ≤ 0.870; and -0.705 ≤ f2 / f23 ≤ -0.521.

[0012] In one embodiment, the optical power of the third lens group is positive. The third lens group includes a seventh lens with positive optical power, an eighth lens with positive optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power arranged in sequence along the optical axis direction. The seventh lens is a plastic aspherical lens, and the ninth lens and the tenth lens are adhesively connected.

[0013] The focal length of the seventh lens is f31, the focal length of the eighth lens is f32, the focal length of the ninth lens is f33, and the focal length of the tenth lens is f34. Among them, 0.479 ≤ f3 / f31 ≤ 0.648; and 0.610 ≤ f3 / f32 ≤ 0.825; and -1.587 ≤ f3 / f33 ≤ -1.173; and 1.048 ≤ f3 / f34 ≤ 1.418.

[0014] In one embodiment, the optical power of the fourth lens group is negative. The fourth lens group includes an eleventh lens with positive optical power and a twelfth lens with positive optical power arranged in sequence along the optical axis direction. The twelfth lens is a plastic aspherical lens.

[0015] The focal length of the eleventh lens is f41, and the focal length of the twelfth lens is f42. Among them, 0.249 ≤ f4 / f41 ≤ 0.337; and 0.569 ≤ f4 / f42 ≤ 0.770.

[0016] In one embodiment, the optical power of the fifth lens group is positive. The fifth lens group includes a thirteenth lens with positive optical power, a fourteenth lens with negative optical power, and a fifteenth lens with negative optical power, which are arranged in sequence along the optical axis direction. The thirteenth lens and the fifteenth lens are adhesively connected.

[0017] The focal length of the thirteenth lens is f51, the focal length of the fourteenth lens is f52, and the focal length of the fifteenth lens is f53. Among them, 1.491 ≤ f5 / f51 ≤ 2.017; and -0.282 ≤ f5 / f51 ≤ -0.209; and -0.699 ≤ f5 / f51 ≤ -0.517.

[0018] In one embodiment, the overall optical length of the zoom optical system is TTL, and TTL ≤ 123.7 mm.

[0019] In one embodiment, the aperture of the zoom optical system is Fno, and 2.82 ≤ Fno ≤ 4.08.

[0020] In one embodiment, the image plane size of the zoom optical system is

[0021] In one embodiment, the zoom optical system further includes a diaphragm and a filter. The diaphragm is disposed between the second lens group and the third lens group, and the filter is disposed between the fifth lens group and the image plane.

[0022] In the technical solution of the present invention, the first lens group and the third lens group are both fixed lens groups. The second lens group and the fifth lens group are both movably arranged along the optical axis direction to zoom the zoom optical system. The fourth lens group moves cooperatively along the optical axis direction to focus the zoom optical system, so that the imaging of the image plane is kept clear during the zooming process of the zoom optical system. With such a setting, by setting the moving strokes of the second lens group, the fourth lens group, and the fifth lens group, the zoom function of the zoom optical system is ensured. At the same time, through conditional restrictions on the ratio of the focal lengths of the five lens groups to the focal length of the zoom optical system at the wide-angle end, and restrictions on the angle range of the zoom optical system, the optical distortion range of the zoom optical system is between -4.04% and 2.94%. Thus, an optical zoom system with a small volume, low distortion, a short focusing object distance, and co-focusing at high and low temperatures is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0024] Figure 1 Schematic diagram of the structure of an embodiment of the zoom optical system (wide-angle end) provided by the present invention;

[0025] Figure 2 Schematic diagram of the structure of an embodiment of the zoom optical system (intermediate magnification) provided by the present invention;

[0026] Figure 3 Schematic diagram of the structure of an embodiment of the zoom optical system (telephoto end) provided by the present invention;

[0027] Figure 4 MTF schematic diagram when the zoom optical system is at the wide-angle end;

[0028] Figure 5 MTF schematic diagram when the zoom optical system is at the intermediate magnification;

[0029] Figure 6 MTF schematic diagram when the zoom optical system is at the telephoto end;

[0030] Figure 7 FCD schematic diagram when the zoom optical system is at the wide-angle end;

[0031] Figure 8 FCD schematic diagram when the zoom optical system is at the intermediate magnification;

[0032] Figure 9 FCD schematic diagram when the zoom optical system is at the telephoto end;

[0033] Figure 10 LON schematic diagram when the zoom optical system is at the wide-angle end;

[0034] Figure 11 LON schematic diagram when the zoom optical system is at the intermediate magnification;

[0035] Figure 12 LON schematic diagram when the zoom optical system is at the telephoto end;

[0036] Figure 13 LAT schematic diagram when the zoom optical system is at the wide-angle end;

[0037] Figure 14 Schematic diagram of LAT when the zoom optical system is at the intermediate magnification;

[0038] Figure 15 Schematic diagram of LAT when the zoom optical system is at the long focal length end.

[0039] Explanation of the reference numerals in the drawings:

[0040] 100. Zoom optical system; 1. First lens group; 11. First lens; 12. Second lens; 13. Third lens; 2. Second lens group; 21. Fourth lens; 22. Fifth lens; 23. Sixth lens; 3. Third lens group; 31. Seventh lens; 32. Eighth lens; 33. Ninth lens; 34. Tenth lens; 4. Fourth lens group; 41. Eleventh lens; 42. Twelfth lens; 5. Fifth lens group; 51. Thirteenth lens; 52. Fourteenth lens; 53. Fifteenth lens; 6. Image plane; 7. Aperture; 8. Filter.

[0041] The realization, functional features and advantages of the purpose of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0042] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts shall fall within the protection scope of the present utility model.

[0043] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative positional relationship and movement conditions between the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, if the descriptions such as "first" and "second" are involved in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0045] The present utility model provides a zoom optical system, aiming to solve the problems that the existing video zoom lenses have low clarity, large volume, unclear focusing at a short object distance, and a small target surface of the photosensitive chip, which can no longer meet the market demand.

[0046] Please refer to Figure 1-3 , in an embodiment of the present utility model, the zoom optical system 100 has an object side and an image side arranged corresponding to each other along the optical axis direction. The zoom optical system 100 includes a first lens group 1, a second lens group 2, a third lens group 3, a fourth lens group 4, a fifth lens group 5, and an image plane 6 arranged in sequence from the object side to the image side. The second lens group 2, the fourth lens group 4, and the fifth lens group 5 are all movably arranged along the optical axis direction. The moving stroke of the second lens group 2 is 26.2 mm, the moving stroke of the fourth lens group 4 is 5.8 mm, and the moving stroke of the fifth lens group 5 is 1.07 mm. The second lens group 2 and the fifth lens group 5 are used for zooming, and the fourth lens group 4 is used for focusing. The focal length of the zoom optical system 100 is f, the focal length of the zoom optical system 100 at the wide-angle end is fw, the focal length of the first lens group 1 is f1, the focal length of the second lens group 2 is f2, the focal length of the third lens group 3 is f3, the focal length of the fourth lens group 4 is f4, and the focal length of the fifth lens group 5 is f5. The zoom optical system 100 satisfies the following conditions: 20.8 mm ≤ f ≤ 59.17 mm; 0.260 ≤ fw / f1 ≤ 0.302; and -1.330 ≤ fw / f2 ≤ -0.983; and 0.867 ≤ fw / f3 ≤ 1.174; and -1.286 ≤ fw / f4 ≤ -0.950; and 0.398 ≤ fw / f5 ≤ 0.539.

[0047] In the technical solution of the present utility model, the first lens group 1 and the third lens group 3 are both fixed lens groups, the second lens group 2 and the fifth lens group 5 are both arranged to be movable along the optical axis to zoom the zoom optical system 100, and the fourth lens group 4 moves cooperatively along the optical axis to focus the zoom optical system 100, so that the imaging of the image plane 6 remains clear during the zooming process of the zoom optical system 100. With such a setting, by setting the moving strokes of the second lens group 2, the fourth lens group 4 and the fifth lens group 5, the zoom function of the zoom optical system 100 is ensured. At the same time, through the conditional limitation of the ratio of the focal lengths of the five lens groups to the focal length of the zoom optical system 100 at the wide-angle end, and the limitation of the angle range of the zoom optical system 100, the optical distortion range of the zoom optical system 100 is between -4.04% and 2.94%. Thus, an optical zoom system with a small volume, small distortion, a short focusing object distance, and co-focusing at high and low temperatures is obtained.

[0048] It should be noted that in the present utility model, the overall optical length TTL of the zoom optical system 100 can be controlled within 123.7 mm, that is, TTL ≤ 123.7 mm.

[0049] In addition, the displacement of the second lens group 2 is ΔZ1(W-T), the displacement of the fourth lens group 4 is ΔZ2(W-T), and the displacement of the objective lens group is ΔZ3(W-T), where 0.184 < ΔZ1(W-T) / TTL < 0.239; and 0.008 < ΔZ2(W-T) / TTL < 0.01; and 0.047 < ΔF(W-T) / TTL < 0.053.

[0050] The present utility model does not limit the specific values of the displacements of the second lens group 2, the fourth lens group 4, and the fifth lens group 5, and only needs to ensure that the displacements of the second lens group 2, the fourth lens group 4, and the fifth lens group 5 are any values within the range.

[0051] It can be understood that the present utility model does not limit the specific driving forms of the second lens group 2, the fourth lens group 4, and the fifth lens group 5 moving along the optical axis. In an embodiment of the present utility model, the second lens group 2, the fourth lens group 4, and the fifth lens group 5 can be driven by a driving motor to move along the optical axis. Specifically, in this embodiment, the output end of the driving motor is drivingly connected to the ball nut of the lead screw structure, and a plurality of ball nuts are movably arranged on the lead screw of the lead screw structure. The second lens group 2, the fourth lens group 4, and the fifth lens group 5 are respectively movably connected to one of the ball nuts. With such a setting, when it is necessary to adjust the position of one of the lens groups, the corresponding ball nut of the lead screw structure is driven to rotate.

[0052] In another embodiment of the present utility model, the second lens group 2, the fourth lens group 4, and the fifth lens group 5 can be adjusted manually by a person. The present utility model does not limit this. During actual setting, selection can be made according to requirements.

[0053] Of course, it can be understood that in the present utility model, the optical power of the first lens group 1 is positive. The first lens group 1 includes a first lens 11 with a negative optical power, a second lens 12 with a positive optical power, and a third lens 13 with a positive optical power, which are arranged in sequence along the optical axis direction.

[0054] In a specific embodiment of the present utility model, the focal length of the first lens 11 is f11, the focal length of the second lens 12 is f12, and the focal length of the third lens 13 is f13. Among them, -0.664 ≤ f1 / f11 ≤ -0.573; and 0.729 ≤ f1 / f12 ≤ 0.845; and 0.706 ≤ f1 / f13 ≤ 0.819.

[0055] It can be understood that the present utility model does not limit the specific values of the focal lengths of the first lens 11, the second lens 12, and the third lens 13. In the embodiments of the present utility model, the first lens 11, the second lens 12, and the third lens 13 can be set to any value within the range.

[0056] Moreover, in this embodiment, the first lens 11 and the second lens 12 are adhesively connected. With such a setting, chromatic aberration of the zoom optical system 100 can be better corrected. At the same time, adhesive connection can also reduce light energy loss, increase imaging clarity, and protect the scale surface, thereby further optimizing the processing flow to meet the design requirements. Therefore, by reasonably using adhesive parts, the image quality of the optical system can be improved by optical components.

[0057] It should also be noted that in this embodiment, the aperture of the first lens 11 is and

[0058] In another embodiment of the present utility model, the optical power of the second lens group 2 is negative. The second lens group 2 includes a fourth lens 21 with a positive optical power, a fifth lens 22 with a positive optical power, and a sixth lens 23 with a negative optical power, which are arranged in sequence along the optical axis direction. The focal length of the fourth lens 21 is f21, the focal length of the fifth lens 22 is f22, and the focal length of the sixth lens 23 is f23. Among them, 0.664 ≤ f2 / f21 ≤ 0.898; and 0.643 ≤ f2 / f22 ≤ 0.870; and -0.705 ≤ f2 / f23 ≤ -0.521.

[0059] Similarly, in this embodiment, the specific numerical values of the focal lengths of the first lens 11, the second lens 12, and the third lens 13 can also be set to any value within a range, and the present invention does not limit this.

[0060] It should also be noted that in a further embodiment of the present invention, the fifth lens 22 and the sixth lens 23 are adhesively connected to further correct the chromatic aberration of the zoom optical system 100 and, at the same time, reduce light energy loss.

[0061] In another embodiment of the present invention, the optical power of the third lens group 3 is positive. The third lens group 3 includes a seventh lens 31 with positive optical power, an eighth lens 32 with positive optical power, a ninth lens 33 with negative optical power, and a tenth lens 34 with positive optical power, which are arranged in sequence along the optical axis. The seventh lens 31 is a plastic aspherical lens, the focal length of the seventh lens 31 is f31, the focal length of the eighth lens 32 is f32, the focal length of the ninth lens 10 is f33, and the focal length of the tenth lens 34 is f34. Among them, 0.479 ≤ f3 / f31 ≤ 0.648; and 0.610 ≤ f3 / f32 ≤ 0.825; and -1.587 ≤ f3 / f33 ≤ -1.173; and 1.048 ≤ f3 / f34 ≤ 1.418.

[0062] Of course, in the present invention, the specific numerical values of the seventh lens 31, the eighth lens 32, the ninth lens 33, and the tenth lens 34 only need to be selected as any value within a range, and the present invention does not limit this.

[0063] At the same time, in this embodiment, the seventh lens 31 is set as a plastic lens to further reduce the manufacturing cost of the zoom optical system 100. Moreover, the seventh lens 31 is set as an aspherical lens. The curvature of the aspherical lens changes continuously from the center of the lens to the periphery of the lens. Different from the spherical lens with a constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using the aspherical lens, the aberration that appears during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens.

[0064] In addition, in another embodiment of the present invention, the optical power of the fourth lens group 4 is negative. The fourth lens group 4 includes an eleventh lens 41 with positive optical power and a twelfth lens 42 with positive optical power, which are arranged in sequence along the optical axis. The focal length of the eleventh lens 41 is f41, and the focal length of the twelfth lens 42 is f42. Among them, 0.249 ≤ f4 / f41 ≤ 0.337; and 0.569 ≤ f4 / f42 ≤ 0.770.

[0065] It can be understood that the present utility model does not limit the specific values of the eleventh lens 41 and the twelfth lens 42 either. During actual setting, any value within the range can be selected for the specific values of the eleventh lens 41 and the twelfth lens 42, and the present utility model does not make any restrictions.

[0066] Similarly, in this embodiment, the twelfth lens 42 is also set as a plastic aspherical lens to further reduce the manufacturing cost of the zoom optical system 100 while improving the imaging quality of the lens.

[0067] In yet another embodiment of the present utility model, the optical power of the fifth lens group 5 is positive. The fifth lens group 5 includes a thirteenth lens 51 with positive optical power, a fourteenth lens 52 with negative optical power, and a fifteenth lens 53 with negative optical power arranged in sequence along the optical axis direction. The focal length of the thirteenth lens 51 is f51, the focal length of the fourteenth lens 52 is f52, and the focal length of the fifteenth lens 53 is f53. Among them, 1.491 ≤ f5 / f51 ≤ 2.017; and -0.282 ≤ f5 / f52 ≤ -0.209; and -0.699 ≤ f5 / f53 ≤ -0.517.

[0068] Certainly, the present utility model also does not limit the specific values of the thirteenth lens 51, the fourteenth lens 52, and the fifteenth lens 53. During actual setting, any value within the range can be selected for the specific values of the eleventh lens 41 and the twelfth lens 42, and the present utility model does not make any restrictions.

[0069] Moreover, in this embodiment, the fourteenth lens 52 and the fifteenth lens 53 are adhesively connected. In this way, it can better correct the chromatic aberration of the zoom optical system 100. At the same time, the adhesive connection can also reduce light energy loss, increase imaging clarity, protect the scale surface, thereby further optimizing the processing flow to meet the design requirements, and enabling the optical components to improve the image quality of the optical system.

[0070] In one embodiment of the present utility model, the aperture of the zoom optical system 100 is Fno, and 2.82 ≤ Fno ≤ 4.08. In this way, the zoom optical system 100 has the characteristic of a large aperture, enabling the zoom optical system 100 to still have excellent imaging effects in low-light environments.

[0071] Furthermore, in another embodiment of the present utility model, the size of the image plane 6 of the zoom optical system 100 is φ, and φ ≤ 25.8 mm. With such a setting, it can ensure the integrity of the imaging of the zoom optical system 100.

[0072] It should also be noted that, in the embodiments of the present utility model, the zoom optical system 100 further includes a diaphragm 7 and a filter 8. The diaphragm 7 is disposed between the second lens group 2 and the third lens group 3, and the filter 8 is disposed on the image side of the fourth lens group 4. The diaphragm 7 is used to adjust the light flux according to actual conditions to improve the imaging quality.

[0073] It should be noted that the distance between the diaphragm 7 and the image plane 6 is L, where L ≤ 61.3 mm, and 0.431 < L / TTL < 0.560.

[0074] In addition, in the above-mentioned multiple embodiments, the first lens 11, the second lens 12, the third lens 13, the fourth lens 21, the fifth lens 22, the sixth lens 23, the eighth lens 32, the ninth lens 33, the tenth lens 34, the eleventh lens 41, the thirteenth lens 51, the fourteenth lens 52, and the fifteenth lens 53 can all be set as glass lenses. By setting them in this way, using lenses made of glass can reduce the influence of temperature on the optical performance of the lens. Glass lenses are not easily affected by thermal expansion and contraction and do not have a focus shift phenomenon. Therefore, glass lenses can well resist the problem of lens deformation due to heat and maintain the high precision of the lens for a long time. The setting of the filter 8 can effectively filter out stray light in non-working wavelength bands to reduce optical noise, making it easier for the subsequent optoelectronic module processing part and thus improving the imaging quality.

[0075] Specifically, in a specific embodiment of the present utility model, the surface type, curvature radius, thickness, material refractive index, and material Abbe number of the lenses in this embodiment are shown in Table 1 below:

[0076] Table 1

[0077]

[0078]

[0079] It should be noted that, in this embodiment, and ΔZ1(W - T) / TTL = 0.212; and ΔZ2(W - T) / TTL = 0.009; and ΔF(W - T) / TTL = 0.041; and L / TTL = 0.495.

[0080] Specifically, the surface shape z of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0081]

[0082] Among them, c is the curvature corresponding to the radius, y is the radial coordinate (with the same unit as the lens length unit), k is the conic coefficient (when the k coefficient is less than -1, the surface curve is a hyperbola; when the k coefficient is equal to -1, it is a parabola; when the k coefficient is between -1 and 0, it is an ellipse; when the k coefficient is equal to 0, it is a circle; when the k coefficient is greater than 0, it is an oblate circle), and A, B, C, D, E, F, G, H are high-order aspheric coefficients. The high-order term coefficients of each aspheric mirror can be seen from Table 2 below:

[0083] Table 2 Conic Coefficient and Aspheric Coefficient Corresponding to Aspheric Lenses

[0084]

[0085] With such settings, by reasonably distributing the lens focal power, adjusting the glass shape and material combination, chromatic aberration and secondary spectrum are effectively eliminated, and spherical aberration, coma, astigmatism, etc. on each lens are compensated and offset from each other to achieve a clear imaging effect and realize the optimal correction of higher-order aberrations and chromatic aberration.

[0086] Figure 4-6 It is the MTF schematic diagram of the zoom optical system 100 described in the present invention at the wide-angle end, intermediate magnification, and telephoto end; Figure 7-9 It is the FCD schematic diagram of the zoom optical system 100 described in the present invention at the wide-angle end, intermediate magnification, and telephoto end; Figure 10-12 It is the LON schematic diagram of the zoom optical system 100 described in the present invention at the wide-angle end, intermediate magnification, and telephoto end; Figure 13-15 It is the LAT schematic diagram of the zoom optical system 100 described in the present invention at the wide-angle end, intermediate magnification, and telephoto end.

[0087] It should be noted that Table 2 is a design value of the aspheric coefficients of the lenses in the zoom optical system 100 in this embodiment. The specific numerical values of the aspheric coefficient design values can be adjusted according to the product requirements, and the present invention does not limit this.

[0088] In addition, the intervals that change between the lens groups of the zoom optical system 100 in this embodiment from the Wide end (wide-angle end) to the Tele end (telephoto end) are as follows:

[0089] Table 3

[0090] Wide Angle Medium Magnification Telephoto Focal Length / mm 20.8 30.23 59.17 Fno Aperture 2.82 3.89 4.08 T(10) 31.080 20.510 4.910 T(22) 9.910 6.220 3.030 T(27) 5.300 6.540 6.370

[0091] The above are only exemplary embodiments of the present utility model, and thus do not limit the patent scope of the present utility model. Any equivalent structural transformation made under the technical concept of the present utility model by using the content of the specification and drawings of the present utility model, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present utility model.

Claims

1. A zoom optical system, characterized in that: The zoom optical system has an object side and an image side correspondingly arranged along the optical axis direction, and comprises a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group and an image plane arranged in sequence from the object side to the image side, the second lens group, the fourth lens group and the fifth lens group are all movably arranged along the optical axis direction, the movable stroke of the second lens group is 26.2 mm, the movable stroke of the fourth lens group is 5.8 mm, and the movable stroke of the fifth lens group is 1.07 mm, the second lens group and the fifth lens group are used for zooming, and the fourth lens group is used for focusing; The focal length of the zoom optical system is f, the focal length of the zoom optical system at the wide-angle end is fw, the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the third lens group is f3, the focal length of the fourth lens group is f4, and the focal length of the fifth lens group is f5. The zoom optical system meets the following conditions: 20.8mm≤f≤59.17mm; 0.260≤fw / f1≤0.302; and -1.330≤fw / f2≤-0.983; and 0.867≤fw / f3≤1.174; and -1.286≤fw / f4≤-0.950; and 0.398≤fw / f5≤0.

539.

2. The zoom optical system according to claim 1, wherein: The optical power of the first lens group is positive, and the first 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, which are arranged in sequence along the optical axis, and the first lens and the second lens are glued together; The focal length of the first lens is f11, the focal length of the second lens is f12, and the focal length of the third lens is f13, wherein -0.664≤f1 / f11≤-0.573; and 0.729≤f1 / f12≤0.845; and 0.706≤f1 / f13≤0.

819.

3. The zoom optical system according to claim 1, wherein: The optical power of the second lens group is negative, and the second lens group comprises a fourth lens with positive optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power, which are arranged in sequence along the optical axis, and the fifth lens and the sixth lens are glued together; The focal length of the fourth lens is f21, the focal length of the fifth lens is f22, and the focal length of the sixth lens is f23, wherein 0.664≤f2 / f21≤0.898; and 0.643≤f2 / f22≤0.870; and -0.705≤f2 / f23≤-0.

521.

4. The zoom optical system according to claim 1, wherein: The third lens group has a positive optical power, and comprises a seventh lens with a positive optical power, an eighth lens with a positive optical power, a ninth lens with a negative optical power, and a tenth lens with a positive optical power, which are sequentially arranged along the optical axis direction, the seventh lens is a plastic aspherical lens, and the ninth lens and the tenth lens are glued together; The focal length of the seventh lens is f31, the focal length of the eighth lens is f32, the focal length of the ninth lens is f33, and the focal length of the tenth lens is f34, wherein 0.479≤f3 / f31≤0.648; and 0.610≤f3 / f32≤0.825; and -1.587≤f3 / f33≤-1.173; and 1.048≤f3 / f34≤1.

418.

5. The zoom optical system according to claim 1, wherein: The fourth lens group has a negative optical power, and comprises an eleventh lens with a positive optical power and a twelfth lens with a positive optical power, which are sequentially arranged along the optical axis, and the twelfth lens is a plastic aspherical lens; The focal length of the eleventh lens is f41, and the focal length of the twelfth lens is f42, wherein 0.249≤f4 / f41≤0.337; and 0.569≤f4 / f42≤0.

770.

6. The zoom optical system according to claim 1, wherein: The optical power of the fifth lens group is positive, and the fifth lens group includes a thirteenth lens with positive optical power, a fourteenth lens with negative optical power, and a fifteenth lens with negative optical power, which are sequentially arranged along the optical axis direction, and the thirteenth lens and the fifteenth lens are cemented together; The focal length of the thirteenth lens is f51, the focal length of the fourteenth lens is f52, and the focal length of the fifteenth lens is f53, wherein 1.491≤f5 / f51≤2.017; and -0.282≤f5 / f51≤-0.209; and -0.699≤f5 / f51≤-0.

517.

7. The zoom optical system according to claim 1, wherein: The total optical length of the zoom optical system is TTL, and TTL≤123.7 mm.

8. The zoom optical system according to claim 1, wherein: The aperture of the zoom optical system is Fno, 2.82≤Fno≤4.

08.

9. The zoom optical system according to claim 1, wherein: The image plane size of the zoom optical system is 10. The zoom optical system according to claim 1, wherein: The zoom optical system further includes an aperture and a filter, wherein the aperture is arranged between the second lens group and the third lens group, and the filter is arranged between the fifth lens group and the image plane.

Images