Zoom optical system and imaging device

Abstract

The utility model provides a kind of zoom optical system and imaging device, it is related to optical technology field, wherein, the zoom optical system includes the first lens group with negative optical power, the second lens group with positive optical power, the third lens group with positive optical power and image plane are sequentially arranged from object side to image side, wherein, the first lens group with the second lens group is movably arranged along the optical axis extension direction, to zoom the zoom optical system.The utility model provides technical scheme, by adopting three groups of element structure, using eleven lenses, and reasonably setting the optical power and the shape matching relationship of each lens group and lens, realize a kind of under the same volume, zoom ratio is larger, imaging quality is higher, target surface is larger and has good zoom optical system of athermalization.

Description

Technical Field

[0001] This utility model relates to the field of optical technology, and in particular to a zoom optical system and imaging device. Background Technology

[0002] A zoom lens is a camera lens that can change its focal length within a certain range, thereby obtaining different widths of field of view, different image sizes, and different ranges of scenery. In the field of video shooting, zoom lenses have been widely used in the market due to their flexibility and consistent image quality.

[0003] Currently, mainstream video zoom lenses on the market have drawbacks such as low resolution, large size, small zoom ratio, and small aperture. Furthermore, the target area of ​​mainstream image sensors on the market is relatively small, which is increasingly unable to meet market demands. Utility Model Content

[0004] The main objective of this invention is to propose a zoom optical system and imaging device, aiming to provide a zoom optical system with a larger zoom ratio, higher imaging quality, larger target surface, and good thermal asymmetry within the same volume.

[0005] To achieve the above objectives, this utility model proposes a zoom optical system. The zoom optical system has an object side and an image side arranged opposite to each other along the optical axis. The zoom optical system includes a first lens group with negative optical power, a second lens group with positive optical power, a third lens group with positive optical power, and an image plane arranged sequentially from the object side to the image side. The first lens group and the second lens group are movably arranged along the extension direction of the optical axis to zoom the zoom optical system. The first lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power arranged sequentially from the object side to the image side; The second lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with negative optical power, an eighth lens with positive optical power, a ninth lens with negative optical power, and a tenth lens with negative optical power, arranged sequentially from the object side to the image side. The third lens group includes an eleventh lens with positive optical power arranged sequentially from the object side to the image side.

[0006] In one embodiment, the zoom optical system further includes an aperture stop disposed between the first lens group and the second lens group.

[0007] In one embodiment, the fifth lens, the sixth lens, and the seventh lens are cemented together.

[0008] In one embodiment, the second lens, the third lens, the fourth lens, the eighth lens, the ninth lens, the tenth lens, and the eleventh lens are all aspherical lenses.

[0009] In one embodiment, the zoom optical system further includes a filter disposed between the eleventh lens and the image plane.

[0010] In one embodiment, the first lens is a concave-convex lens, and its object-side surface is convex. The second lens is a biconcave lens; The third lens is a biconvex lens; The fourth lens is a biconvex lens; The fifth lens is a biconvex lens; The sixth lens is a biconcave lens; The seventh lens is a biconvex lens; The eighth lens is a concave-convex lens, and its object-side surface is concave. The ninth lens is a biconcave lens; The tenth lens is a concave-convex lens, and its object-side surface is convex. The eleventh lens is a concave-convex lens, and its object-side surface is concave.

[0011] In one embodiment, 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 first lens is f11, the focal length of the second lens is f12, the focal length of the third lens is f13, the focal length of the fourth lens is f21, the focal length of the fifth lens is f22, the focal length of the sixth lens is f23, the focal length of the seventh lens is f24, the focal length of the eighth lens is f25, the focal length of the ninth lens is f26, and the focal length of the tenth lens is f27; wherein... 0.744≤f1 / f11≤1.007, 0.556≤f1 / f12≤0.753, -0.541≤f1 / f13≤-0.400, 0.662≤f2 / f21≤0.896, 0.286≤f2 / f22≤0.387, -0.780≤f2 / f23≤-0.577, -0.420≤f2 / f24≤-0.310, 0.517≤f2 / f25≤0.700, -0.344≤f2 / f26≤-0.254, -0.027≤f2 / f27≤-0.020.

[0012] In one embodiment, 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, and the focal length of the zoom optical system at the wide-angle end is f; wherein, -0.587≤f / f1≤-0.434, 0.323≤f / f2≤0.437, 0.051≤f / f3≤0.069.

[0013] This invention also proposes an imaging device, which includes the above-mentioned zoom optical system. The zoom optical system has an object side and an image side arranged opposite to each other along the optical axis. The zoom optical system includes a first lens group with negative optical power, a second lens group with positive optical power, a third lens group with positive optical power, and an image plane arranged sequentially from the object side to the image side. The first lens group and the second lens group are movably arranged along the extension direction of the optical axis to zoom the zoom optical system. The first lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power arranged sequentially from the object side to the image side; The second lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, 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 negative optical power, arranged sequentially from the object side to the image side. The third lens group includes an eleventh lens with positive optical power arranged sequentially from the object side to the image side.

[0014] The technical solution provided by this utility model effectively collects light over a wider range by setting the first lens group with negative optical power, and changes the propagation direction of the beam, correcting aberrations in the off-axis field of view, which is more conducive to the beam forming on the image plane. The light path of this lens is smooth, and the structure is more compact while introducing more light. The lens proposed in this solution has high imaging quality, can support a target surface of φ9.2mm, and has good high and low temperature adaptability and more stable working performance. By adopting a three-element structure, using eleven lenses, and rationally setting the optical power and shape matching relationship of each lens group and lens, a zoom optical system with a larger zoom ratio, higher imaging quality, larger target surface, and good thermal aberration reduction is achieved in the same volume. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 A schematic diagram of a structure of an embodiment of the zoom optical system provided by this utility model; Figure 2 for Figure 1 A schematic diagram of field curvature distortion in a medium zoom optical system.

[0017] Explanation of icon numbers: 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; 24. Seventh lens; 25. Eighth lens; 26. Ninth lens; 27. Tenth lens; 3. Third lens group; 31. Eleventh lens; 4. Aperture stop; 5. Filter; 6. Image plane.

[0018] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0020] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0022] A zoom lens is a camera lens that can change its focal length within a certain range, thereby obtaining different widths of field of view, different image sizes, and different ranges of scenery. In the field of video shooting, zoom lenses have been widely used in the market due to their flexibility and consistent image quality.

[0023] Currently, mainstream video zoom lenses on the market have drawbacks such as low resolution, large size, small zoom ratio, and small aperture. Furthermore, the target area of ​​mainstream image sensors on the market is relatively small, which is increasingly unable to meet market demands.

[0024] The main objective of this invention is to propose a zoom optical system and imaging device, aiming to provide a zoom optical system with a larger zoom ratio, higher imaging quality, larger target surface, and good thermal asymmetry within the same volume.

[0025] Please see Figure 1 This invention proposes a zoom optical system 100, which has an object side and an image side arranged opposite to each other along the optical axis. The zoom optical system 100 includes a first lens group 1 with negative optical power, a second lens group 2 with positive optical power, a third lens group 3 with positive optical power, and an image plane 6 arranged sequentially from the object side to the image side. The first lens group 1 and the second lens group 2 are movably arranged along the optical axis to zoom the zoom optical system 100. The first lens group 1 includes a first lens group 2 arranged sequentially from the object side to the image side. The first lens group 11 has negative optical power, the second lens 12 has negative optical power, and the third lens 13 has positive optical power; the second lens group 2 includes a fourth lens 21 with positive optical power, a fifth lens 22 with positive optical power, a sixth lens 23 with negative optical power, a seventh lens 24 with negative optical power, an eighth lens 25 with positive optical power, a ninth lens 26 with negative optical power, and a tenth lens 27 with negative optical power, arranged sequentially from the object side to the image side; the third lens group 3 includes an eleventh lens 31 with positive optical power, arranged sequentially from the object side to the image side.

[0026] The technical solution provided by this utility model effectively collects light over a wider range by setting the first lens group 1 with negative optical power, and changes the propagation direction of the beam, correcting aberrations in the off-axis field of view, which is more conducive to the beam imaging on the image plane 6. The light path of this lens is smooth, and the structure is more compact while introducing more light. The lens proposed in this solution has high imaging quality, can support a target surface of φ9.2mm, and has good high and low temperature adaptability and more stable working performance. By adopting a three-element structure, using eleven lenses, and rationally setting the optical power and shape matching relationship of each lens group and lens, a zoom optical system 100 with a larger zoom ratio, higher imaging quality, larger target surface, and good thermal aberration reduction is achieved in the same volume.

[0027] Furthermore, the zoom optical system 100 also includes an aperture stop 4, which is disposed between the first lens group 1 and the second lens group 2. The aperture stop 4 limits the light beam aperture on the optical axis, blocking part of the light, thereby reducing light spots, improving image contrast, and also expanding the target surface and improving image quality. Adjusting the light throughput of the aperture stop 4 according to actual conditions helps to further improve image quality.

[0028] Furthermore, to improve the image quality of the optical system, reduce light energy loss, increase imaging clarity, protect the scale surface, and further optimize the manufacturing process to meet design requirements, in this embodiment, the fifth lens 22, the sixth lens 23, and the seventh lens 24 are cemented together. Thus, the reasonable use of cemented components and the reasonable allocation of optical power effectively correct aberrations and achieve a heat-free effect at high and low temperatures. It also effectively reduces chromatic aberration, achieving a clear image across the confocal plane in both the visible and near-infrared bands.

[0029] Furthermore, the second lens 12, the third lens 13, the fourth lens 21, the eighth lens 25, the ninth lens 26, the tenth lens 27, and the eleventh lens 31 are all aspherical lenses. It should be noted that the characteristic of aspherical lenses is that the curvature changes continuously from the center to the periphery of the lens, unlike spherical lenses which have a constant curvature from the center to the periphery.

[0030] It should be further noted that the aspherical lenses in the zoom optical system 100 provided in this embodiment can all be plastic aspherical lenses, while lenses other than aspherical lenses can be spherical glass lenses. The glass and plastic materials can compensate for each other, thereby balancing high and low temperatures and reducing the overall optical length of the lens. This results in the zoom optical system 100 exhibiting stable performance at high and low temperatures, improving its environmental adaptability, and providing better aberration correction. By rationally combining the temperature coefficients of the glass-plastic hybrid materials, good resolution of the lens can be ensured under high and low temperature conditions, and the lens weight can be significantly reduced. Furthermore, compared to glass lenses, plastic lenses have a significant cost advantage, reducing the overall cost of the zoom optical system 100.

[0031] Furthermore, the zoom optical system 100 also includes a filter 5, which is disposed between the eleventh lens 31 and the image plane 6 to filter out stray light in non-operating wavelength bands. The filter 5 can reduce optical noise, thus reducing difficulties for subsequent optoelectronic module processing.

[0032] In this embodiment, specifically, please refer to Figure 1The first lens 11 is a concave-convex lens with a convex object-side surface; the second lens 12 is a biconcave lens; the third lens 13 is a biconvex lens; the fourth lens 21 is a biconvex lens; the fifth lens 22 is a biconvex lens; the sixth lens 23 is a biconcave lens; the seventh lens 24 is a biconvex lens; the eighth lens 25 is a concave-convex lens with a concave object-side surface; the ninth lens 26 is a biconcave lens; the tenth lens 27 is a concave-convex lens with a convex object-side surface; and the eleventh lens 31 is a concave-convex lens with a concave object-side surface.

[0033] Further, 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 first lens 11 is f11, the focal length of the second lens 12 is f12, the focal length of the third lens 13 is f13, the focal length of the fourth lens 21 is f21, the focal length of the fifth lens 22 is f22, the focal length of the sixth lens 23 is f23, the focal length of the seventh lens 24 is f24, the focal length of the eighth lens 25 is f25, the focal length of the ninth lens 26 is f26, and the focal length of the tenth lens 27 is f27; wherein, 0 0.744≤f1 / f11≤1.007,0.556≤f1 / f12≤0.753,-0.541≤f1 / f13≤-0.400,0.662≤f2 / f21≤0.896,0.286≤f2 / f22≤0.387,-0.780≤f2 / f23≤-0.577,-0.420≤f2 / f24≤-0.310,0.517≤f2 / f25≤0.700,-0.344≤f2 / f26≤-0.254,-0.027≤f2 / f27≤-0.020。 By limiting the focal length of each lens, a reasonable combination of the optical power of each lens can be achieved, allowing light to pass through the zoom optical system 100 more smoothly and correcting the impact of aberrations on image quality to a greater extent.

[0034] Furthermore, 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, and the focal length of the zoom optical system 100 at the wide-angle end is f; wherein, -0.587≤f / f1≤-0.434, 0.323≤f / f2≤0.437, and 0.051≤f / f3≤0.069. By limiting the focal length of each lens group, a reasonable combination of optical power of each lens group can be achieved, allowing light to pass through the zoom optical system 100 more smoothly and correcting the impact of aberrations on image quality to a greater extent.

[0035] It is worth mentioning that the surface shape of each aspherical lens in the zoom optical system 100 described in this embodiment should satisfy the following equation:

[0036] Where c is the curvature corresponding to the radius; y is the radial coordinate (its unit is the same as the lens length unit); k is the conic section coefficient, and A, B, C, D, E, F, G, H... represent the second, fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth... aspherical coefficients, respectively. These parameters allow the setting of the shape and size of the aspherical surfaces facing the object and image sides of the lens.

[0037] Specifically, when k < -1, the corresponding lens surface curve is a hyperbola; when k = -1, the corresponding lens surface curve is a parabola; when -1 < k < 0, the corresponding lens surface curve is an ellipse; when k = 0, the corresponding lens surface curve is a circle; and when k > 0, the corresponding lens surface curve is an oval.

[0038] It should be noted that the basic parameters of the zoom optical system 100 in this embodiment are shown in Table 1, where the units of radius of curvature, thickness and focal length are all millimeters (mm).

[0039] Table 1

[0040] It should be noted that the basic parameters of the zoom optical system 100 at the wide-angle end and the telephoto end in this embodiment are shown in Table 2, where the units of zoom 1, zoom 2, zoom 3 and focal length are all millimeters (mm).

[0041] Table 2

[0042] In this embodiment, the aspherical coefficients of each aspherical lens in the zoom optical system 100 include: the quadratic surface coefficient k, the second-order aspherical coefficient A, the fourth-order aspherical coefficient B, the sixth-order aspherical coefficient C, the eighth-order aspherical coefficient D, the tenth-order aspherical coefficient E, the twelfth-order aspherical coefficient F, the fourteenth-order aspherical coefficient G, and the sixteenth-order aspherical coefficient H, as shown in Table 3 below.

[0043] Table 3

[0044] In this embodiment, the total optical length of the zoom optical system 100 is 52 mm, and the target surface diameter is 9.2 mm. It can be seen that the zoom optical system 100 in this embodiment has the characteristic of a large target surface for the same optical length.

[0045] In this embodiment, the ratio of the focal length of each lens, the focal length of the lens group, the focal length at the wide-angle end to the focal length of each lens group, and the ratio of the focal length of each lens group to the focal length of each lens within the group are shown in Table 5 below. All focal lengths are in millimeters.

[0046] Table 5

[0047] Please refer to Figure 2 This diagram illustrates the field curvature distortion of the zoom optical system 100 in this embodiment. Different colors represent different wavelengths. For the same color, the right curve represents the meridional direction, and the left curve represents the sagittal field curvature. The diagram shows that the sagittal field curvature of this lens at the wide-angle end is no greater than 0.08mm, indicating that this lens can effectively correct chromatic aberration. The other curve in the diagram is the system's distortion curve. Distortion does not affect the system's sharpness, but it can cause image distortion. The optical distortion of this system is less than 65%.

[0048] This utility model also proposes an imaging device, which includes the above-mentioned zoom optical system 100. Since the imaging device includes the zoom optical system 100, the specific structure of the zoom optical system 100 is as described in the above embodiments. Since the zoom optical system 100 of this imaging device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0049] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within 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 arranged opposite to each other along the optical axis. The zoom optical system includes a first lens group with negative optical power, a second lens group with positive optical power, a third lens group with positive optical power, and an image plane arranged sequentially from the object side to the image side. The first lens group and the second lens group are movably arranged along the extension direction of the optical axis to zoom the zoom optical system. The first lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power arranged sequentially from the object side to the image side; The second lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with negative optical power, an eighth lens with positive optical power, a ninth lens with negative optical power, and a tenth lens with negative optical power, arranged sequentially from the object side to the image side. The third lens group includes an eleventh lens with positive optical power arranged sequentially from the object side to the image side.

2. The zoom optical system according to claim 1, characterized by The zoom optical system also includes an aperture stop, which is located between the first lens group and the second lens group.

3. The zoom optical system according to claim 1, wherein The fifth lens, the sixth lens, and the seventh lens are cemented together.

4. The zoom optical system according to claim 1, characterized by The second, third, fourth, eighth, ninth, tenth, and eleventh lenses are all aspherical lenses.

5. The zoom optical system according to claim 1, wherein The zoom optical system also includes a filter, which is disposed between the eleventh lens and the image plane.

6. The zoom optical system according to claim 1, characterized by The first lens is a concave-convex lens, and its object-side surface is convex. The second lens is a biconcave lens; The third lens is a biconvex lens; The fourth lens is a biconvex lens; The fifth lens is a biconvex lens; The sixth lens is a biconcave lens; The seventh lens is a biconvex lens; The eighth lens is a concave-convex lens, and its object-side surface is concave. The ninth lens is a biconcave lens; The tenth lens is a concave-convex lens, and its object-side surface is convex. The eleventh lens is a concave-convex lens, and its object-side surface is concave.

7. The zoom optical system according to claim 1, wherein 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 first lens is f11, the focal length of the second lens is f12, the focal length of the third lens is f13, the focal length of the fourth lens is f21, the focal length of the fifth lens is f22, the focal length of the sixth lens is f23, the focal length of the seventh lens is f24, the focal length of the eighth lens is f25, the focal length of the ninth lens is f26, and the focal length of the tenth lens is f27; wherein... 0.744≤f1 / f11≤1.007, 0.556≤f1 / f12≤0.753, -0.541≤f1 / f13≤-0.400, 0.662≤f2 / f21≤0.896, 0.286≤f2 / f22≤0.387, -0.780≤f2 / f23≤-0.577, -0.420≤f2 / f24≤-0.310, 0.517≤f2 / f25≤0.700, -0.344≤f2 / f26≤-0.254, -0.027≤f2 / f27≤-0.

020.

8. The zoom optical system according to claim 1, characterized by 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, and the focal length of the zoom optical system at the wide-angle end is f; wherein, -0.587≤f / f1≤-0.434, 0.323≤f / f2≤0.437, 0.051≤f / f3≤0.

069.

9. An image forming apparatus characterized by comprising: Includes the zoom optical system as described in any one of claims 1-8.

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