A compact camera lens

Abstract

This utility model relates to the field of camera lenses, and more particularly to a compact camera lens, comprising: a first lens group, a second lens group, and a third lens group arranged sequentially along the light-gathering direction, with a variable aperture between the first lens group and the second lens group. The lens's length and maximum image height are characterized by the following condition: TTL / Ymax < 6; where TTL is the total length from the vertex of the first lens surface in the first lens group to the image plane, and Ymax is the paraxial maximum image height at infinity. By employing high-refractive-index optical glass and a compact lens group arrangement, the lens body length is shortened and weight reduced while maintaining a maximum aperture of F1.7, achieving true portability while ensuring image quality. An aspherical lens is used at the front end to reduce field curvature and distortion. Increasing the optical power ratio of the moving group reduces the travel of the moving group, further shortening the overall lens body length.

Description

Technical Field

[0001] This utility model relates to the field of camera lenses, and more particularly to a compact camera lens. Background Technology

[0002] High-specification camera lenses, in pursuit of ultimate optical specifications and performance, often employ complex lens group structures, resulting in a large lens body and significantly increased weight. This bulk not only increases the photographer's burden, leading to fatigue during extended handheld shooting, but also limits the flexibility of shooting scenarios when using a tripod. Furthermore, the excessive size increases the burden of carrying, requiring a dedicated camera bag for outdoor shooting, which is inconvenient for ordinary shooting needs such as recording everyday life, street photography, and travel photography. Utility Model Content

[0003] The purpose of this invention is to provide a compact camera lens to solve the aforementioned technical problems.

[0004] The technical solution of this utility model is implemented as follows: A compact camera lens includes: a first lens group, a second lens group, and a third lens group arranged sequentially along the light-incident direction, and a variable aperture is provided between the first lens group and the second lens group. The lens's length and maximum image height are characterized by satisfying the following condition: TTL / Ymax < 6; Where TTL is the total length from the vertex of the first lens surface in the first lens group to the image plane, and Ymax is the maximum paraxial image height at infinity.

[0005] Optionally, the first lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the light-gathering direction, wherein the first lens in the first lens group is an aspherical negative lens bent towards the image plane, satisfying the following condition: (L1R2+L1R1) / (L1R2-L1R1) < -2; Wherein, L1R1 is the radius of curvature of the side of the negative lens closest to the object, and L1R2 is the radius of curvature of the side of the negative lens closest to the image plane.

[0006] Optionally, at least one biconvex positive lens in the first lens group satisfies the following condition: P5 / Ymax < 3.6; 1.1 < F5 / f < 1.5; Wherein, P5 is the total length from the vertex of the image-side surface of the positive lens to the imaging plane, Ymax is the maximum paraxial image height at infinity, F5 is the focal length of the positive lens, and f is the focal length of the optical system.

[0007] Optionally, the second lens group includes a sixth lens and a seventh lens arranged sequentially along the light-incident direction, wherein the sixth lens is a negative lens and the seventh lens is a positive lens, and the second lens group is moved towards the image side to achieve focusing from infinity to near distance, satisfying the following conditions: 1.6 < |F7 / F6| < 2.1; 3 < |FG2 / f| < 3.6; Wherein, F7 is the focal length of the positive lens in the second lens group; F6 is the focal length of the negative lens in the second lens group; FG2 is the focal length of the second lens group; and f is the focal length of the optical system.

[0008] Optionally, the third lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens arranged sequentially along the light-gathering direction, wherein the ninth and tenth lenses form a pair of cemented doublet lenses, the eleventh and twelfth lenses form a pair of cemented doublet lenses, and at least two lenses satisfy the following condition: vdn > 70; Where vdn is the Abbe number of the lens.

[0009] Optionally, the third lens group satisfies the following conditions: 2.1 < FG3 / f < 2.8; Where FG3 is the focal length of the third lens group, and f is the focal length of the optical system.

[0010] The beneficial effects of this utility model are: Employing high-refractive-index optical glass and a compact lens arrangement, this lens achieves true portability while maintaining a maximum aperture of F1.7 and shortening its overall length. An aspherical lens is used at the front to reduce field curvature and distortion. The optical power ratio of the moving group is increased, thereby reducing its travel and further shortening the overall lens length. The moving group uses a combination of negative and positive lenses, resulting in excellent imaging at infinity and close distances. The use of ultra-low dispersion and anomalous dispersion materials effectively reduces chromatic aberration and color fringing, restoring true-to-life colors. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments 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 these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of the compact camera lens described in the embodiment; Figure 2This is a spherical aberration curve of the compact camera lens described in this embodiment of the present invention; Figure 3 This is a field curvature curve diagram of the compact camera lens described in this embodiment of the present invention; Figure 4 This is a distortion curve diagram of the compact camera lens described in an embodiment of the present invention.

[0013] Icon labels: G1 - First lens group; 1 - First lens; 2 - Second lens; 3 - Third lens; 4 - Fourth lens; 5 - Fifth lens; G2 - Second lens group; 6 - Sixth lens; 7 - Seventh lens; G3 - Third lens group; 8 - Eighth lens; 9 - Ninth lens; 10 - Tenth lens; 11 - Eleventh lens; 12 - Twelfth lens. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0015] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0016] Example 1: As Figure 1 As shown, a compact camera lens includes: a first lens group G1, a second lens group G2, and a third lens group G3 arranged sequentially along the light-gathering direction, and a variable aperture is provided between the first lens group G1 and the second lens group G2. The relationship between the length of the lens and the maximum image height satisfies the following condition: TTL / Ymax < 6; Where TTL is the total length from the vertex of the first lens surface in the first lens group G1 to the image plane, and Ymax is the maximum paraxial image height at infinity.

[0017] Secondly, the first lens group G1 includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a fifth lens 5 arranged sequentially along the light-gathering direction. The first lens 1 in the first lens group G1 is an aspherical negative lens bent towards the image plane, satisfying the following condition: (L1R2+L1R1) / (L1R2-L1R1) < -2; Wherein, L1R1 is the radius of curvature of the side of the negative lens closest to the object, and L1R2 is the radius of curvature of the side of the negative lens closest to the image plane.

[0018] Secondly, at least one biconvex positive lens in the first lens group G1 satisfies the following condition: P5 / Ymax < 3.6; 1.1 < F5 / f < 1.5; Wherein, P5 is the total length from the vertex of the image-side surface of the positive lens to the imaging plane, Ymax is the maximum paraxial image height at infinity, F5 is the focal length of the positive lens, and f is the focal length of the optical system.

[0019] Secondly, the second lens group G2 includes a sixth lens 6 and a seventh lens 7 arranged sequentially along the light-gathering direction, wherein the sixth lens 6 is a negative lens and the seventh lens 7 is a positive lens, and the second lens group G2 moves towards the image side to achieve focusing from infinity to near distance, satisfying the following conditions: 1.6 < |F7 / F6| < 2.1; 3 < |FG2 / f| < 3.6; Wherein, F7 is the focal length of the positive lens in the second lens group G2; F6 is the focal length of the negative lens in the second lens group G2; FG2 is the focal length of the second lens group G2; and f is the focal length of the optical system.

[0020] Secondly, the third lens group G3 includes an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, and a twelfth lens 12 arranged sequentially along the light-gathering direction. Among them, the ninth lens 9 and the tenth lens 10 form a pair of cemented doublet lenses, and the eleventh lens 11 and the twelfth lens 12 form a pair of cemented doublet lenses. At least two lenses satisfy the following condition: vdn > 70; Where vdn is the Abbe number of the lens.

[0021] Secondly, the third lens group satisfies the following conditions: 2.1 < FG3 / f < 2.8; Where FG3 is the focal length of the third lens group, and f is the focal length of the optical system.

[0022] In the specific implementation process, the radius of curvature, thickness, refractive index, and dispersion coefficient of each lens surface from the object side (the side of the photographed object) to the image side (the side of the image sensor or film) are shown in Table 1: Table 1 1 44.73 0.9 1.5158 63.99 2 19.6 8.888 3 -24.886 0.9 1.74 28.296 4 125.674 5.4 1.755 52.322 5 -34.395 0.15 6 295.416 3.978 1.8061 41.017 7 -83.838 0.15 8 121.401 5.32 1.755 52.322 9 -47.891 1.22 10 INFINITY D1 11 -161.489 0.9 1.6889 31.161 12 41.853 1.489 13 161.511 2.8 1.946 17.942 14 -161.511 D2 15 44.513 4.567 1.497 81.605 16 -44.513 0.15 17 56.091 3 1.804 46.574 18 -75.377 0.9 1.5891 61.253 19 19.554 1.804 20 51.761 5.574 1.497 81.605 21 -17.580 0.9 1.6889 31.161 22 1120 10.33 23 INFINITY 1.5 1.5168 64.199 24 INFINITY 2 Radius of curvature (mm): Indicates the degree of curvature of the lens surface. Positive values ​​represent convex surfaces, and negative values ​​represent concave surfaces.

[0023] Thickness (mm): refers to the distance between two adjacent surfaces, i.e., the thickness of the lens or air gap.

[0024] Refractive index: the ability of a material to bend light, used to calculate the change in direction of light as it passes through a lens.

[0025] Dispersion coefficient (Abbe number): A numerical value that describes the dispersion characteristics of a material. The larger the value, the smaller the color difference.

[0026] The aspherical coefficients of aspherical positive lenses are shown in Table 2: Table 2 k 3.452 0.289 A4 -2.492e-05 -6.884e-08 A6 8.507e-08 -8.298e-08 A8 -4.241e-10 -2.647e-10 A10 -1.41e-13 2.039e-12 A12 3.278e-15 -5.772e-15 A14 1.075e-18 -8.736e-19 A16 -1.452e-20 5.339e-21 k: Conic constant, used to adjust the shape of aspherical surfaces.

[0027] A4, A6, A8, A10, A12, A14, A16: Higher-order aspherical coefficients, which affect the precise shape of the lens surface to optimize optical performance.

[0028] The specific values ​​of D1 and D2 in Table 1 at different focusing distances are shown in Table 3: Table 3 D1 2.98mm 10.78mm D2 9.1mm 1.3mm Infinity: The dimensions of each distance when the lens is focused at infinity.

[0029] Closest (0.35m): The dimensions of each distance when the lens is focused at the closest working distance.

[0030] In summary, the key specifications of a compact camera lens in this embodiment are shown in Table 4: Table 4 Relative aperture FNO. 1.85 Field of view ω 57.38° Overall optical length 74.9mm like Figure 2 The figure shows a spherical aberration curve of a compact camera lens according to this embodiment, where the horizontal axis represents spherical aberration and the vertical axis represents the normalized entrance pupil. As can be seen from the figure, the spherical aberration of the three different wavelengths of light converges to a very small range, allowing the lens to obtain a clear and transparent image.

[0031] like Figure 3 The figure shows the field curvature curve of a compact camera lens according to this embodiment, where the horizontal axis represents the field curvature, the vertical axis represents the image height, the T-line represents the meridional direction, and the S-line represents the sagittal direction. As can be seen from the figure, the image can be imaged on the same plane across the entire frame without any local blurring. Furthermore, the small distance between the meridional and sagittal curves indicates uniform image formation in different directions.

[0032] like Figure 4 The figure shows the distortion curve of a compact camera lens according to this embodiment, where the horizontal axis represents distortion and the vertical axis represents image height. As can be seen from the figure, the distortion is controlled below 3% across the entire frame.

[0033] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A compact camera lens, comprising: A first lens group, a second lens group, and a third lens group are arranged sequentially along the light-gathering direction, and a variable aperture is provided between the first lens group and the second lens group. The lens is characterized in that the relationship between its length and maximum image height satisfies the following condition: TTL / Ymax < 6; Where TTL is the total length from the vertex of the first lens surface in the first lens group to the image plane, and Ymax is the maximum paraxial image height at infinity.

2. A compact camera lens according to claim 1, characterized in that, The first lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the light-gathering direction. The first lens in the first lens group is an aspherical negative lens bent towards the image plane, satisfying the following condition: (L1R2+L1R1) / (L1R2-L1R1) < -2; Wherein, L1R1 is the radius of curvature of the side of the negative lens closest to the object, and L1R2 is the radius of curvature of the side of the negative lens closest to the image plane.

3. A compact camera lens according to claim 1, characterized in that, The first lens group contains at least one biconvex positive lens that satisfies the following condition: P5 / Ymax < 3.6; 1.1 < F5 / f < 1.5; Wherein, P5 is the total length from the vertex of the image-side surface of the positive lens to the imaging plane, Ymax is the maximum paraxial image height at infinity, F5 is the focal length of the positive lens, and f is the focal length of the optical system.

4. A compact camera lens according to claim 1, characterized in that, The second lens group includes a sixth lens and a seventh lens arranged sequentially along the light-gathering direction, wherein the sixth lens is a negative lens and the seventh lens is a positive lens, and the second lens group is moved towards the image side to achieve focusing from infinity to near distance, satisfying the following conditions: 1.6 < |F7 / F6| < 2.1; 3 < |FG2 / f| < 3.6; Wherein, F7 is the focal length of the positive lens in the second lens group; F6 is the focal length of the negative lens in the second lens group; FG2 is the focal length of the second lens group; and f is the focal length of the optical system.

5. A compact camera lens according to claim 1, characterized in that, The third lens group includes the eighth, ninth, tenth, eleventh, and twelfth lenses arranged sequentially along the light-gathering direction. The ninth and tenth lenses form a pair of cemented doublet lenses, and the eleventh and twelfth lenses form a pair of cemented doublet lenses. At least two lenses satisfy the following condition: vdn > 70; Where vdn is the Abbe number of the lens.

6. A compact camera lens according to claim 5, characterized in that, The third lens group satisfies the following conditions: 2.1 < FG3 / f < 2.8; Where FG3 is the focal length of the third lens group, and f is the focal length of the optical system.

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