Camera lens and imaging apparatus

Abstract

Based on the technical field of optics, the camera lens comprises a first lens group with positive focal power, a second lens group with negative focal power and a third lens group with positive focal power which are sequentially arranged from an object side to an image side, and the second lens group is movably arranged in the direction of an optical axis to achieve focusing; the first lens group comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power and a fifth lens with positive focal power; the second lens group comprises a sixth lens with negative focal power, a seventh lens with positive focal power and an eighth lens with negative focal power; and the third lens group comprises a ninth lens with positive focal power, a tenth lens with positive focal power, an eleventh lens with negative focal power and a twelfth lens with negative focal power. According to the scheme, the camera lens is small in size, large in aperture and high in imaging quality.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a camera lens and imaging device. Background Technology

[0002] With the rapid development of social media platforms and the popularity of short video content, more and more users tend to record and share their daily lives with others by shooting vlogs. Users not only pursue high-quality still images but also pay special attention to the expressiveness and stability of video content to ensure viewers have the best viewing experience. This has spurred the rapid growth of the market for high-performance, compact photography equipment, especially mini cameras that are easy to carry and operate without compromising image quality, which have gained widespread popularity.

[0003] Among these factors, the camera lens plays a crucial role in the performance of mini cameras. Existing large-aperture mini camera lenses typically employ complex optical structures to correct aberrations, resulting in a large number of lens elements and making it difficult to achieve substantial size reduction and weight reduction. Some manufacturers have also launched lightweight mini camera lenses, but these lenses often suffer from reduced edge sharpness, significant chromatic aberration, and poor distortion control at their widest aperture. Summary of the Invention

[0004] The main objective of this invention is to provide a camera lens and imaging device, which aims to provide a camera lens with small size, large aperture, and high image quality.

[0005] To achieve the above objectives, the present invention proposes a camera lens having an object side and an image side arranged opposite to each other along the optical axis. The camera lens includes a first lens group with positive optical power, a second lens group with negative 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 third lens group are fixedly arranged, while the second lens group is movable along the optical axis to achieve focusing. The first lens group includes a first lens with negative optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with positive optical power, and a fifth lens with positive optical power, arranged sequentially from the object side to the image side. The second lens group includes a sixth lens with negative optical power, a seventh lens with positive optical power, and an eighth lens with negative optical power, arranged sequentially from the object side to the image side. The third lens group includes a ninth lens with positive optical power, a tenth lens with positive optical power, an eleventh lens with negative optical power, and a twelfth lens with negative optical power, arranged sequentially from the object side to the image side. The total optical length of the camera lens is TTL, and the focal length is f, satisfying: 1.8≤TTL / f≤2.8.

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

[0007] In one embodiment, the camera lens further includes a filter disposed sequentially from the object side to the image side between the twelfth lens and the image plane, the filter being used to filter out stray light.

[0008] In one embodiment, the third lens is cemented to the fourth lens, the seventh lens is cemented to the eighth lens, and the tenth lens is cemented to the eleventh lens.

[0009] In one embodiment, the first lens or the second lens is configured as a glass aspherical lens.

[0010] In one embodiment, the twelfth lens is configured as a glass aspherical lens.

[0011] In one embodiment, the focal length of the camera lens is f, the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the focal length of the third lens group is f3, satisfying: 0.7≤f1 / f≤1.5, -3.0≤f2 / f≤-2.0, 2.8≤f3 / f≤3.7.

[0012] In one embodiment, the refractive index of the second lens is n2, the refractive index of the seventh lens is n7, and the dispersion coefficient of the seventh lens is v7, satisfying: 1.8≤n2≤2.0, 1.8≤n7≤2.1, 15≤v7≤30.

[0013] In one embodiment, the refractive index of the fifth lens is n5, and the dispersion coefficient of the fifth lens is v5, satisfying: 1.6≤n5≤1.85, 40≤v5≤90.

[0014] The present invention also proposes a camera device, the camera device including the above-mentioned camera lens, the camera lens having an object side and an image side arranged opposite to each other along the optical axis, the camera lens including a first lens group with positive optical power, a second lens group with negative optical power, a third lens group with positive optical power and an image plane arranged sequentially from the object side to the image side, wherein the first lens group and the third lens group are fixedly arranged, and the second lens group is movable along the optical axis to achieve focusing; The first lens group includes a first lens with negative optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with positive optical power, and a fifth lens with positive optical power, arranged sequentially from the object side to the image side. The second lens group includes a sixth lens with negative optical power, a seventh lens with positive optical power, and an eighth lens with negative optical power, arranged sequentially from the object side to the image side. The third lens group includes a ninth lens with positive optical power, a tenth lens with positive optical power, an eleventh lens with negative optical power, and a twelfth lens with negative optical power, arranged sequentially from the object side to the image side. The total optical length of the camera lens is TTL, and the focal length is f, satisfying: 1.8≤TTL / f≤2.8.

[0015] The technical solution provided by this invention compensates for the change in angle of view during camera zoom by setting a movable second lens group, thereby achieving focusing at different object distances. The lens exhibits a smooth light path, introducing more light while making the structure more compact. By employing appropriate optical power, it not only efficiently deflects light but also effectively controls the size and weight of the lens, meeting users' requirements for compactness and lightweight design. In terms of aperture, the aperture value can reach F1.4, allowing for clear imaging even in low light. This solution, through the use of a three-element structure and only twelve lenses, and the rational setting of the number of lenses and optical power in each lens group, achieves a camera lens with a small size, large aperture, and high image quality. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of a camera lens according to an embodiment of the present invention at an infinity focusing distance; Figure 2 for Figure 1 A schematic diagram of the structure of a camera lens at its closest focusing distance (0.4m); Figure 3 for Figure 1 MTF diagram of a camera lens at infinity focusing distance; Figure 4 for Figure 1 MTF diagram of a medium-sized camera lens at its closest focusing distance (0.4m); Figure 5 for Figure 1 MTF diagram of a camera lens at -10℃; Figure 6 for Figure 1 MTF diagram of a medium-sized camera lens at 60℃; Figure 7 for Figure 1 Lateral chromatic aberration curve of a camera lens at infinity focusing distance; Figure 8 for Figure 1 Lateral chromatic aberration curve of a medium-sized camera lens at its closest focusing distance (0.4m); Figure 9 for Figure 1 Field curvature distortion of a camera lens at infinity focusing distance.

[0018] Explanation of icon numbers: 1000. Camera lens; 1. First lens group; 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 15. Fifth lens; 2. Second lens group; 21. Sixth lens; 22. Seventh lens; 23. Eighth lens; 3. Third lens group; 31. Ninth lens; 32. Tenth lens; 33. Eleventh lens; 34. Twelfth lens; 4. Aperture stop; 5. Filter; 6. Image plane.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention 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.

[0022] Furthermore, if the embodiments of this invention 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. Thus, 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 invention.

[0023] With the rapid development of social media platforms and the popularity of short video content, more and more users tend to record and share their daily lives with others by shooting vlogs. Users not only pursue high-quality still images but also pay special attention to the expressiveness and stability of video content to ensure viewers have the best viewing experience. This has spurred the rapid growth of the market for high-performance, compact photography equipment, especially mini cameras that are easy to carry and operate without compromising image quality, which have gained widespread popularity.

[0024] Among these factors, the camera lens plays a crucial role in the performance of mini cameras. Existing large-aperture mini camera lenses typically employ complex optical structures to correct aberrations, resulting in a large number of lens elements and making it difficult to achieve substantial size reduction and weight reduction. Some manufacturers have also launched lightweight mini camera lenses, but these lenses often suffer from reduced edge sharpness, significant chromatic aberration, and poor distortion control at their widest aperture.

[0025] The main objective of this invention is to provide a camera lens and imaging device, which aims to provide a camera lens with small size, large aperture, and high image quality.

[0026] Please see Figure 1This invention proposes a camera lens 1000, which has an object side and an image side arranged opposite to each other along the optical axis. The camera lens 1000 includes a first lens group 1 with positive optical power, a second lens group 2 with negative 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 third lens group 3 are fixedly arranged, while the second lens group 2 is movable along the optical axis to achieve focusing. The first lens group 1 includes a first lens 11 with negative optical power, a second lens 12 with positive optical power, and an image plane 6, arranged sequentially from the object side to the image side. The third lens group 13 has a negative optical power, the fourth lens 14 has a positive optical power, and the fifth lens 15 has a positive optical power; the second lens group 2 includes a sixth lens 21 with a negative optical power, a seventh lens 22 with a positive optical power, and an eighth lens 23 with a negative optical power, arranged sequentially from the object side to the image side; the third lens group 3 includes a ninth lens 31 with a positive optical power, a tenth lens 32 with a positive optical power, an eleventh lens 33 with a negative optical power, and a twelfth lens 34 with a negative optical power, arranged sequentially from the object side to the image side; the total optical length of the camera lens 1000 is TTL, and the focal length is f, satisfying: 1.8≤TTL / f≤2.8.

[0027] The technical solution provided by this invention compensates for the change in angle of view during camera zoom by setting a movable second lens group 2, thereby achieving focusing at different object distances. The lens exhibits a smooth light path, introducing more light while making the structure more compact. By employing appropriate optical power, it not only efficiently deflects light but also effectively controls the size and weight of the lens, meeting users' requirements for compactness and lightweight design. In terms of aperture, the aperture value F can reach 1.4, allowing for clear imaging even in low light. This solution, through the use of a three-element structure and only twelve lenses, and by rationally setting the number of lenses and optical power in each lens group, achieves a small-volume, large-aperture, high-image-quality camera lens 1000.

[0028] Furthermore, the camera lens 1000 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 some light rays, thereby reducing glare, improving image contrast, and also improving image quality. Adjusting the light throughput of the aperture stop 4 according to actual conditions helps to further improve image quality. In this embodiment, a variable aperture can be placed at the aperture stop 4 to achieve aperture changes from F1.4 to F16.

[0029] Furthermore, the filter 5 is disposed between the twelfth lens 34 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 in subsequent optoelectronic module processing.

[0030] 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 third lens 13 and the fourth lens 14 are cemented together, the seventh lens 22 and the eighth lens 23 are cemented together, and the tenth lens 32 and the eleventh lens 33 are cemented together. Thus, the rational 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, enabling simultaneous clarity of the confocal plane in both the visible and near-infrared imaging bands.

[0031] Furthermore, in one embodiment of the present invention, the first lens 11 or the second lens 12 is configured as a glass aspherical lens; in another embodiment of the present invention, the twelfth lens 34 is configured as a glass aspherical lens. It should be noted that the characteristic of an aspherical lens is that its curvature changes continuously from the center to the periphery, unlike a spherical lens which has a constant curvature from the center to the periphery. This solution effectively corrects the transverse aberration associated with a large aperture by using a glass lens and improves the thermal stability of the lens, ensuring that the lens does not lose focus under high or low temperature conditions, thus adapting to different environments.

[0032] In this embodiment, specifically, please refer to Figure 1 The first lens 11 is a concave-convex lens with a convex object-side surface; the second lens 12 is a concave-convex lens with a convex object-side surface; the third lens 13 is a biconcave lens; the fourth lens 14 is a biconvex lens; the fifth lens 15 is a biconvex lens; the sixth lens 21 is a concave-convex lens with a convex object-side surface; the seventh lens 22 is a biconvex lens; the eighth lens 23 is a biconcave lens; the ninth lens 31 is a biconvex lens; the tenth lens 32 is a biconvex lens; the eleventh lens 33 is a biconcave lens; and the twelfth lens 34 is a concave-convex lens with a concave object-side surface.

[0033] Furthermore, the focal length of the camera lens 1000 is f, the focal length of the first lens group 1 is f1, the focal length of the second lens group 2 is f2, and the focal length of the third lens group 3 is f3, satisfying: 0.7 ≤ f1 / f ≤ 1.5, -3.0 ≤ f2 / f ≤ -2.0, and 2.8 ≤ f3 / f ≤ 3.7. By limiting the focal length of each lens group, a reasonable combination of the optical power of each lens can be achieved, allowing light to pass through the camera lens 1000 more smoothly and correcting the impact of aberrations on image quality to a greater extent.

[0034] Furthermore, in one embodiment provided by the present invention, the refractive index of the second lens 12 is n2, the refractive index of the seventh lens 22 is n7, and the dispersion coefficient of the seventh lens 22 is v7, satisfying: 1.8≤n2≤2.0, 1.8≤n7≤2.1, 15≤v7≤30. In another embodiment provided by the present invention, the refractive index of the fifth lens 15 is n5, and the dispersion coefficient of the fifth lens 15 is v5, satisfying: 1.6≤n5≤1.85, 40≤v5≤90. By combining different lenses and rationally allocating their refractive indices and dispersion coefficients, the camera lens 1000 has high imaging quality and low distortion.

[0035] It is worth mentioning that the surface shape of each aspherical lens in the camera lens 1000 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 conic coefficient, and A, B, C, D, E, F, G, H... represent the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth... 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 camera lens 1000 at infinity focusing distance in this embodiment are shown in Table 1, where the units of radius of curvature, thickness and semi-diameter are all millimeters (mm).

[0039] Table 1

[0040] In this embodiment, the aspherical coefficients of each aspherical lens in the camera lens 1000 include: the quadratic surface coefficient k, the fourth-order aspherical coefficient A, the sixth-order aspherical coefficient B, the eighth-order aspherical coefficient C, the tenth-order aspherical coefficient D, the twelfth-order aspherical coefficient E, the fourteenth-order aspherical coefficient F, the sixteenth-order aspherical coefficient G, and the eighteenth-order aspherical coefficient H, as shown in Table 2 below.

[0041] Table 2

[0042] Please refer to Figures 3 to 4 This is a schematic diagram of the MTF of the camera lens 1000 at the infinity focusing distance and the closest focusing distance (0.4m) in this embodiment. As can be seen from the figure, the MTF of the lens is greater than 0.4 at the infinity focusing distance and greater than 0.1 at the closest focusing distance (0.4m), which basically meets the imaging quality requirements.

[0043] Please refer to Figures 5 to 6 The figure shows the MTF of the camera lens 1000 in this embodiment at -10℃ and 60℃. As can be seen from the figure, the lens can ensure an MTF greater than 0.1 under both high and low temperature conditions, indicating that the lens in this embodiment has good heat dissipation.

[0044] Please refer to Figures 7 to 8 Figure 1 shows the lateral chromatic aberration curves of the camera lens 1000 at infinity focusing distance and closest focusing distance (0.4m) in this embodiment. As can be seen from the figure, the lateral chromatic aberration of the camera lens 1000 at infinity focusing distance is controlled within the range of (-1.5μm, +4.5μm), and the lateral chromatic aberration at the closest focusing distance (0.4m) is controlled within the range of (-3.5μm, +3μm). This indicates that the lateral chromatic aberration of the camera lens 1000 is well controlled and has high color fidelity.

[0045] Please refer to Figure 9 This diagram illustrates the field curvature distortion of the camera lens 1000 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 is no greater than 0.08mm, indicating that the lens can effectively correct chromatic aberration. The other curve in the diagram is the system distortion curve. Distortion does not affect the system's sharpness, but it can cause image distortion. The optical distortion of this lens is less than 1.6%.

[0046] In this embodiment, the maximum aperture of the lens in the camera lens 1000 is 26mm, the total optical length is less than 65mm, and the overall weight is less than 55g. It can achieve an image quality level of 50M resolution, can be matched with an APS-C chip, and the aperture value can reach 1.4. While having a large field of view, this lens corrects various aberrations, resulting in high image quality. It can also produce clear images in low light. Furthermore, the lens is small in size and light in weight, meeting the user's miniaturization needs.

[0047] The present invention also proposes a camera device, which includes the camera lens 1000 described above. Since the camera device includes the camera lens 1000, the specific structure of the camera lens 1000 is as described in the above embodiments. Since the camera lens 1000 of the present camera 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.

[0048] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A camera lens, characterized in that, The camera lens has an object side and an image side that are arranged opposite to each other along the optical axis. The camera lens includes a first lens group with positive optical power, a second lens group with negative 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 third lens group are fixedly arranged, and the second lens group is movable along the optical axis to achieve focusing. The first lens group includes a first lens with negative optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with positive optical power, and a fifth lens with positive optical power, arranged sequentially from the object side to the image side. The second lens group includes a sixth lens with negative optical power, a seventh lens with positive optical power, and an eighth lens with negative optical power arranged sequentially from the object side to the image side. The third lens group includes a ninth lens with positive optical power, a tenth lens with positive optical power, an eleventh lens with negative optical power, and a twelfth lens with negative optical power, arranged sequentially from the object side to the image side. The total optical length of the camera lens is TTL, and the focal length is f, satisfying: 1.8≤TTL / f≤2.

8.

2. The camera lens as described in claim 1, characterized in that, The camera lens also includes an aperture stop, which is located between the first lens group and the second lens group.

3. The camera lens as described in claim 1, characterized in that, The camera lens also includes a filter disposed sequentially from the object side to the image side between the twelfth lens and the image plane, the filter being used to filter out stray light.

4. The camera lens as described in claim 1, characterized in that, The third lens is cemented to the fourth lens, the seventh lens is cemented to the eighth lens, and the tenth lens is cemented to the eleventh lens.

5. The camera lens as described in claim 1, characterized in that, The first lens or the second lens is configured as a glass aspherical lens.

6. The camera lens as described in claim 1, characterized in that, The twelfth lens is configured as a glass aspherical lens.

7. The camera lens as described in claim 1, characterized in that, The camera lens has a focal length of f, the first lens group has a focal length of f1, the second lens group has a focal length of f2, and the third lens group has a focal length of f3, satisfying: 0.7≤f1 / f≤1.5, -3.0≤f2 / f≤-2.0, 2.8≤f3 / f≤3.

7.

8. The camera lens as described in claim 1, characterized in that, The refractive index of the second lens is n2, the refractive index of the seventh lens is n7, and the dispersion coefficient of the seventh lens is v7, satisfying: 1.8≤n2≤2.0, 1.8≤n7≤2.1, 15≤v7≤30.

9. The camera lens as described in claim 1, characterized in that, The refractive index of the fifth lens is n5, and the dispersion coefficient of the fifth lens is v5, satisfying: 1.6≤n5≤1.85, 40≤v5≤90.

10. A camera device, characterized in that, Includes the camera lens as described in any one of claims 1 to 9.

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