Long-focus lens and electronic device

Abstract

The present invention discloses a telephoto lens and an electronic device, which include a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from the object side to the image side; the first lens has a positive optical power, and the object side surface of the first lens is a convex surface; the second lens has a negative optical power, and the curvature radius L2R1 of the object side surface of the second lens satisfies 5 mm < L2R1 < 15 mm; the third lens has a positive optical power, and the curvature radius L3R1 of the object side surface of the third lens satisfies 3 mm < L3R1 < 11 mm; the fourth lens has a positive optical power; the fifth lens has a negative optical power, the object side surface of the fifth lens is a convex surface at the paraxial region, the image side surface of the fifth lens is a concave surface at the paraxial region, and at least one of the object side surface and the image side surface of the fifth lens has at least one inflection point. The telephoto lens and the electronic device of the present invention have the advantages of lens miniaturization, large aperture, and good resolution.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and particularly to a telephoto lens and an electronic device. Background Art

[0002] With the development of the multifunctionalization of various electronic products, the camera function has become an essential function of many electronic products, such as smartphones and tablet computers with camera functions. However, with the increasing requirements of users for lenses, there are generally problems such as large size, small aperture, and poor resolution. There is a need to provide a miniaturized telephoto lens with a large aperture and good resolution. Summary of the Invention

[0003] In view of the above problems, the object of the present invention is to provide a telephoto lens and an electronic device, which have lens miniaturization, a large aperture, and good resolution.

[0004] The present invention provides a telephoto lens. The telephoto lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from the object side to the image side; the first lens has a positive optical power, and the object side surface of the first lens is a convex surface; the second lens has a negative optical power, and the curvature radius L2R1 of the object side surface of the second lens satisfies 5 mm < L2R1 < 15 mm; the third lens has a positive optical power, and the curvature radius L3R1 of the object side surface of the third lens satisfies 3 mm < L3R1 < 11 mm; the fourth lens has a positive optical power; the fifth lens has a negative optical power, the object side surface of the fifth lens is convex at the paraxial region, the image side surface of the fifth lens is concave at the paraxial region, and at least one of the object side surface and the image side surface of the fifth lens has at least one inflection point.

[0005] Optionally, the sag SAG11 of the object side surface of the fifth lens and the sag SAG12 of the image side surface of the fifth lens satisfy: -1 mm < SAG11 < -0.3 mm, -1 mm < SAG12 < -0.2 mm, -0.8 mm < SAG11 - SAG12 < 0 mm.

[0006] Optionally, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.7 < f1 / |f2| < 1.3.

[0007] Optionally, the refractive index N2 of the second lens satisfies: 1.6 < N2.

[0008] Optionally, the object side diameter D7 of the third lens and the image side diameter D8 of the third lens satisfy: 2.8 mm < D7 < 3.5 mm, 2.8 mm < D8 < 3.6 mm.

[0009] Optionally, the object-side diameter D9 of the fourth lens and the image-side diameter D10 of the fourth lens satisfy: 3.2 mm < D9 < 3.7 mm, 3.3 mm < D10 < 3.7 mm.

[0010] Optionally, the object-side diameter D11 of the fifth lens and the image-side diameter D10 of the fourth lens satisfy: 0.5 mm < D11 - D10 < 0.85 mm.

[0011] Optionally, the focal length f3 of the third lens, the focal length f4 of the fourth lens, and the focal length f5 of the fifth lens satisfy: 20 mm < max(abs(f3, f4, f5)) < 1000 mm.

[0012] Optionally, the focal length f1 of the first lens and the focal length f′ of the telephoto lens satisfy: 0.45 < f1 / f′ < 0.75.

[0013] Optionally, the telephoto lens further includes an aperture, and the aperture is disposed on the object side surface of the first lens.

[0014] Optionally, the telephoto lens further includes a filter, and the filter is disposed between the fifth lens and the imaging surface.

[0015] The present invention further provides an electronic device including the above-mentioned telephoto lens.

[0016] The telephoto lens and the electronic device provided by the present invention, the telephoto lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from the object side to the image side; the first lens has a positive optical power, and the object side surface of the first lens is a convex surface; the second lens has a negative optical power, and the object side surface curvature radius L2R1 of the second lens satisfies 5 mm < L2R1 < 15 mm; the third lens has a positive optical power, and the object side surface curvature radius L3R1 of the third lens satisfies 3 mm < L3R1 < 11 mm; the fourth lens has a positive optical power; the fifth lens has a negative optical power, the object side surface of the fifth lens is convex at the paraxial region, the image side surface of the fifth lens is concave at the paraxial region, and at least one of the object side surface and the image side surface of the fifth lens has at least one anastigmatic point. The first lens can play a role in condensing light, the second lens to the fourth lens can play a role in aberration correction, and the fifth lens can play a role in increasing the main ray incident angle. According to the optical power distribution of the first lens to the fifth lens, and by reasonably distributing the optical power, spacing, and refractive index of each lens, lens miniaturization, large aperture, and good resolution can be achieved. Description of the Drawings

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of a telephoto lens according to an embodiment of this application is shown.

[0019] Figure 2 A schematic diagram of the structure of a telephoto lens according to Embodiment 1 of this application is shown.

[0020] Figures 3 to 5 The light aberration diagram, distortion diagram, and MTF curve of the telephoto lens of Example 1 are shown respectively.

[0021] Figure 6 A schematic diagram of the structure of a telephoto lens according to Embodiment 2 of this application is shown.

[0022] Figures 7 to 9 The light aberration diagram, distortion diagram, and MTF curve of the telephoto lens of Example 2 are shown respectively.

[0023] Figure 10 A schematic diagram of the structure of a telephoto lens according to Embodiment 3 of this application is shown.

[0024] Figures 11 to 13 The light aberration diagram, distortion diagram, and MTF curve of the telephoto lens of Example 3 are shown respectively. Detailed Implementation

[0025] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the present invention; some well-known parts may not be shown. In the various drawings, the same elements are represented by similar reference numerals. For clarity, the various parts in the drawings are not necessarily drawn strictly to scale.

[0026] It is important to understand that the terms "first," "second," "third," "fourth," etc., are used merely to distinguish elements or circuits with similar properties, and do not indicate or imply relative importance or a specific order. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the listed elements but also other elements not expressly listed.

[0027] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0028] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane (IMG) is called the image-side surface of the lens.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] The features, principles and other aspects of this application are described in detail below.

[0031] Figure 1 A schematic diagram of the structure of a telephoto lens according to an embodiment of this application is shown.

[0032] The telephoto lens according to an exemplary embodiment of the present application includes, from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. The first lens L1 has a positive optical power, and the object side surface of the first lens L1 is convex. The second lens L2 has a negative optical power, and the radius of curvature L2R1 of the object side surface of the second lens L2 satisfies 5 mm < L2R1 < 15 mm. The third lens L3 has a positive optical power, and the radius of curvature L3R1 of the object side surface of the third lens L3 satisfies 3 mm < L3R1 < 11 mm. The fourth lens L4 has a positive optical power. The fifth lens L5 has a negative optical power. The object side surface of the fifth lens L5 is convex at the paraxial region, the image side surface of the fifth lens L5 is concave at the paraxial region, and at least one of the object side surface and the image side surface of the fifth lens L5 has at least one inflection point. Specifically, the first lens L1 has a positive optical power and can play a role in converging light. The second lens L2 to the fourth lens L4 can play a role in correcting aberrations. The inflection point of the fifth lens L5 can optimize the light focusing, reduce distortion, and improve the optical performance. The fifth lens L5 can play a role in increasing the incident angle of the chief ray. According to the optical power distribution of the first lens L1 to the fifth lens L5, and by reasonably allocating the optical power, spacing, and refractive index of each lens, lens miniaturization, a large aperture, and good resolution can be achieved. At the same time, by satisfying the shapes of each lens, it is possible to control that each lens maintains a similar and small mechanical aperture as a whole. The tolerance sensitivity of the lens is low, each lens is easy to process, and the lens is easy to assemble.

[0033] In an exemplary embodiment, for the telephoto lens according to the present application, -1 mm < SAG11 < -0.3 mm, -1 mm < SAG12 < -0.2 mm, and -0.8 mm < SAG11 - SAG12 < 0 mm can be satisfied, where SAG11 is the sag of the object side surface of the fifth lens L5, and SAG12 is the sag of the image side surface of the fifth lens L5. By satisfying -1 mm < SAG11 < -0.3 mm, -1 mm < SAG12 < -0.2 mm, and -0.8 mm < SAG11 - SAG12 < 0 mm, by controlling the sag SAG11 of the object side surface of the fifth lens L5 and the sag SAG12 of the image side surface of the fifth lens L5, it is beneficial to control the incident angle of the chief ray and avoid vignetting and color deviation.

[0034] In an exemplary embodiment, for the telephoto lens according to the present application, 0.7 < f1 / |f2| < 1.3 can be satisfied, where f1 is the focal length of the first lens L1 and f2 is the focal length of the second lens L2. By satisfying 0.7 < f1 / |f2| < 1.3, by controlling the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2, it is beneficial to correct spherical aberration and improve resolution.

[0035] In one exemplary embodiment, the telephoto lens according to the present application further satisfies 1.6 < N2, where N2 is the refractive index of the second lens L2. By satisfying 0.7 < f1 / |f2| < 1.3 and 1.6 < N2 and controlling the focal length f1 of the first lens L1, the focal length f2 of the second lens L2, and the refractive index N2 of the second lens L2, it is more beneficial to correct spherical aberration and improve resolution.

[0036] In an exemplary embodiment, the telephoto lens according to the present application may satisfy 2.8 mm < D7 < 3.5 mm and 2.8 mm < D8 < 3.6 mm, where D7 is the object-side diameter of the third lens L3 and D8 is the image-side diameter of the third lens L3. By satisfying 2.8 mm < D7 < 3.5 mm and 2.8 mm < D8 < 3.6 mm and controlling the object-side diameter D7 and the image-side diameter D8 of the third lens L3, it is beneficial to correct off-axis field aberration, improve resolution, and maintain a small mechanical aperture. The tolerance sensitivity of the lens is low, each lens is easy to process, and the lens is easy to assemble.

[0037] In an exemplary embodiment, the telephoto lens according to the present application may satisfy 3.2 mm < D9 < 3.7 mm and 3.3 mm < D10 < 3.7 mm, where D9 is the object-side diameter of the fourth lens L4 and D10 is the image-side diameter of the fourth lens L4. By satisfying 3.2 mm < D9 < 3.7 mm and 3.3 mm < D10 < 3.7 mm and controlling the object-side diameter D9 and the image-side diameter D10 of the fourth lens L4, it is beneficial to correct off-axis field aberration, improve resolution, and maintain a small mechanical aperture. The tolerance sensitivity of the lens is low, each lens is easy to process, and the lens is easy to assemble.

[0038] In an exemplary embodiment, the telephoto lens according to the present application may satisfy 0.5 mm < D11 - D10 < 0.85 mm, where D11 is the object-side diameter of the fifth lens L5 and D10 is the image-side diameter of the fourth lens L4. By satisfying 0.5 mm < D11 - D10 < 0.85 mm and controlling the object-side diameter D11 of the fifth lens L5 and the image-side diameter D10 of the fourth lens L4, it is beneficial to correct off-axis field aberration and improve resolution.

[0039] In one exemplary embodiment, the telephoto lens according to the present application satisfies 2.8 mm < D7 < 3.5 mm, 2.8 mm < D8 < 3.6 mm, 3.2 mm < D9 < 3.7 mm, 3.3 mm < D10 < 3.7 mm, 0.5 mm < D11 - D10 < 0.85 mm, where the object-side diameter of the third lens L3 is D7, the image-side diameter of the third lens L3 is D8, the object-side diameter of the fourth lens L4 is D9, the image-side diameter of the fourth lens L4 is D10, and the object-side diameter of the fifth lens L5 is D11. By satisfying 2.8 mm < D7 < 3.5 mm, 2.8 mm < D8 < 3.6 mm, 3.2 mm < D9 < 3.7 mm, 3.3 mm < D10 < 3.7 mm, 0.5 mm < D11 - D10 < 0.85 mm, and controlling the object-side diameter D9 of the fourth lens L4, the image-side diameter D10 of the fourth lens L4, the object-side diameter D9 of the fourth lens L4, the image-side diameter D10 of the fourth lens L4, and the object-side diameter D11 of the fifth lens L5, it is possible to better facilitate the correction of off-axis field aberration and improve the resolution.

[0040] In an exemplary embodiment, the telephoto lens according to the present application satisfies 20 mm < max(abs(f3, f4, f5)) < 1000 mm, where the focal length of the third lens L3 is f3, the focal length of the fourth lens L4 is f4, and the focal length of the fifth lens L5 is f5. By satisfying 20 mm < max(abs(f3, f4, f5)) < 1000 mm, and for the focal lengths f3 of the third lens L3, f4 of the fourth lens L4, and f5 of the fifth lens L5, the larger the absolute value of the focal length, the more beneficial it is to reduce the aberration of a single lens.

[0041] In an exemplary embodiment, the telephoto lens according to the present application satisfies 0.45 < f1 / f′ < 0.75, where the focal length of the first lens L1 is f1 and the focal length of the telephoto lens is f′. By satisfying 0.45 < f1 / f′ < 0.75 and controlling the ratio of the focal length f1 of the first lens L1 to the focal length f′ of the telephoto lens, it is beneficial for light convergence.

[0042] In an exemplary embodiment, the mobile phone lens according to the present application further includes an aperture STO, and the aperture STO can be disposed on the object side of the first lens L1 or between adjacent lenses.

[0043] In an exemplary embodiment, the mobile phone lens according to the present application further includes a filter IR for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface IMG, and the filter IR can be disposed between the fifth lens L5 and the imaging surface IMG.

[0044] Based on the same inventive concept, the electronic device according to the exemplary embodiments of this application includes the telephoto lens described above. The electronic device includes, but is not limited to, smartphones, tablets, laptops, gimbal cameras, surveillance cameras, and other imaging devices. Implementations of this electronic device can refer to embodiments of the telephoto lens; repeated details will not be elaborated further.

[0045] However, those skilled in the art will understand that the number of lenses constituting the optical imaging lens can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although five lenses are described as an example in the embodiments, the optical imaging lens is not limited to including five lenses. If desired, the optical imaging lens may also include other numbers of lenses.

[0046] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the telephoto lens applicable to the above-described embodiments.

[0047] Example 1

[0048] The following is for reference Figure 2 A telephoto lens according to Embodiment 1 of this application is described. Figure 2 A schematic diagram of the equivalent alternative optical structure of the telephoto lens according to Embodiment 1 of this application is shown.

[0049] The telephoto lens of Embodiment 1 comprises, from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. An aperture stop STO can be disposed on the object side of the first lens L1. A filter IR is disposed between the fifth lens L5 and the imaging plane IMG.

[0050] The first lens L1 has positive optical power, with a convex object-side surface and a flat image-side surface. The second lens L2 has negative optical power, with a convex object-side surface and a concave image-side surface. The third lens L3 has positive optical power, with a convex object-side surface and a concave image-side surface. The fourth lens L4 has positive optical power, with a convex object-side surface and a convex image-side surface. The fifth lens L5 has negative optical power, with a convex object-side surface and a concave image-side surface. The filter IR has an object-side surface and an image-side surface. Light from the object passes sequentially through the object-side and image-side surfaces of the first lens L1 to the fifth lens L5 and the filter IR, and is finally imaged on the imaging plane IMG.

[0051] Table 1 shows the basic parameters of the telephoto lens in Example 1, where the units for radius of curvature, thickness, focal length, mechanical diameter, and elevation are all millimeters (mm).

[0052] Table 1:

[0053]

[0054] Wherein, L1 R1 represents the object-side surface of the first lens L1, L1 R2 represents the image-side surface of the first lens L1, L2 R1 represents the object-side surface of the second lens L2, L2 R2 represents the image-side surface of the second lens L2, L3 R1 represents the object-side surface of the third lens L3, L3 R2 represents the image-side surface of the third lens L3, L4 R1 represents the object-side surface of the fourth lens L4, L4 R2 represents the image-side surface of the fourth lens L4, L5 R1 represents the object-side surface of the fifth lens L5, L5 R2 represents the image-side surface of the fifth lens L5, IR R1 represents the object-side surface of the filter IR, and IR R2 represents the image-side surface of the filter IR.

[0055] In Embodiment 1, the object-side surface and image-side surface of any one of the first lens L1 to the fifth lens L5 are both even-order aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0056] (1)

[0057] Where Z represents the height along the optical axis, c is the reciprocal of the surface radius, k is the conic coefficient, and r is the aperture along the radial direction; α represents the aspherical coefficient, α1 represents the aspherical coefficient A2, α2 represents the aspherical coefficient A4, and so on. Table 2 gives the higher-order coefficients A2, A4, A6, A8, A10, A12, A14, and A16 that can be used for each aspherical mirror in Example 1.

[0058] Table 2:

[0059]

[0060] In Example 1, based on the optical power distribution of the first lens L1 to the fifth lens L5 in the table above, and the reasonable allocation of the optical power, spacing, and refractive index of each lens, a telephoto lens with a long focal length and a large aperture can be achieved. Specifically, the focal length f′ of the telephoto lens is 10.69mm, the aperture is f / 2.14, the imaging circle diameter is 7.06mm, and the field of view is 31.7°. The total optical length of existing mobile phone lenses is typically between 3mm and 5mm. In this example, the total optical length of the telephoto lens is 3.6mm, achieving miniaturization of the telephoto lens. Furthermore, all lenses in this example maintain a similar and small mechanical aperture overall, resulting in low tolerance sensitivity, ease of processing, and ease of assembly. The object-side sagitta of the fifth lens L5 is SAG11 = -0.548 mm, and the image-side sagitta of the fifth lens L5 is SAG12 = -0.500 mm, so SAG11 - SAG12 = -0.048 mm; the relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 / |f2| = -0.900; the refractive index of the second lens L2 is N2 = 1.660; the object-side diameter of the third lens L3 is D7 = 3.388 mm, the image-side diameter of the third lens L3 is D8 = 3.388 mm, the object-side diameter of the fourth lens L4 is D9 = 3.481 mm, the image-side diameter of the fourth lens L4 is D10 = 3.481 mm, and the relationship between the object-side diameter D11 of the fifth lens L5 and the image-side diameter D10 of the fourth lens L4 is D11 - D10 = 0.667 mm. The object-side surface curvature radius of the second lens L2 is L2R1=6.187mm, the object-side surface curvature radius of the third lens L3 is L3R1=6.783mm, the focal length f3 of the third lens L3, the focal length f4 of the fourth lens L4 and the focal length f5 of the fifth lens L5 are related by max(abs(f3, f4, f5))=42.288mm, and the focal length f1 of the first lens L1 and the focal length f′ of the telephoto lens are related by f1 / f′=0.587.

[0061] Figure 3 The light aberration diagram of the telephoto lens of Example 1 is shown, with a scale of ±20µm, indicating good aberration correction. Figure 4 The distortion diagram of the telephoto lens of Example 1 is shown, with optical distortion of less than 0.5%, which is very small. Figure 5 The MTF (Modulation Transfer Function) curve of the telephoto lens in Example 1 is shown. The MTF curve illustrates the transmission of image details (i.e., image contrast) at different spatial frequencies by the imaging system. At a spatial frequency of 250 lp / mm, the MTF value is greater than 0.2, indicating excellent resolution. According to... Figures 3 to 5It can be seen that the telephoto lens given in Example 1 has well corrected aberrations, small distortion and good resolution, and can achieve good image quality.

[0062] Example 2

[0063] The following is for reference Figure 6 This application describes a telephoto lens according to Embodiment 2. For the sake of brevity, descriptions similar to those in Embodiment 1 are omitted in this embodiment. Figure 6 A schematic diagram of the structure of a telephoto lens according to Embodiment 2 of this application is shown.

[0064] The telephoto lens of Embodiment 2 comprises, from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. An aperture stop STO can be disposed on the object side of the first lens L1. A filter IR is disposed between the fifth lens L5 and the imaging plane IMG.

[0065] The first lens L1 has positive optical power, with a convex object-side surface and a flat image-side surface. The second lens L2 has negative optical power, with a convex object-side surface and a concave image-side surface. The third lens L3 has positive optical power, with a convex object-side surface and a concave image-side surface. The fourth lens L4 has positive optical power, with a concave object-side surface and a convex image-side surface. The fifth lens L5 has negative optical power, with a convex object-side surface and a concave image-side surface. The filter IR has an object-side surface and an image-side surface. Light from the object passes sequentially through the object-side and image-side surfaces of the first lens L1 to the fifth lens L5 and the filter IR, and is finally imaged on the imaging plane IMG.

[0066] Table 3 shows the basic parameters of the telephoto lens in Example 2, where the units for radius of curvature, thickness, focal length, mechanical diameter, and elevation are all millimeters (mm).

[0067] Table 3:

[0068]

[0069] Table 4 shows the higher-order coefficients that can be used for each aspherical mirror in Example 2, wherein each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0070] Table 4:

[0071]

[0072] In Example 2, based on the optical power distribution of the first lens L1 to the fifth lens L5 in the table above, and the reasonable allocation of the optical power, spacing, and refractive index of each lens, a telephoto lens with a long focal length and large aperture can be achieved. Specifically, the focal length f′ of the telephoto lens is 10.7mm, the aperture is f / 2.14, the imaging circle diameter is 6.89mm, and the field of view is 31.7°. The total optical length of existing mobile phone lenses is typically between 3mm and 5mm. In this example, the total optical length of the telephoto lens is 3.7mm, achieving miniaturization of the telephoto lens. Furthermore, all lenses in this example maintain a similar and small mechanical aperture overall, resulting in low tolerance sensitivity, easy processing of each lens, and easy assembly of the lens. The object-side sagitta of the fifth lens L5 is SAG11 = -0.416 mm, and the image-side sagitta of the fifth lens L5 is SAG12 = -0.212 mm, so SAG11 - SAG12 = -0.204 mm; the relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 / |f2| = -1.005; the refractive index of the second lens L2 is N2 = 1.660; the object-side diameter of the third lens L3 is D7 = 3.370 mm, and the image-side diameter of the third lens L3 is D8 = 3.370 mm; the object-side diameter of the fourth lens L4 is D9 = 3.433 mm, and the image-side diameter of the fourth lens L4 is D10 = 3.433 mm; the relationship between the object-side diameter D11 of the fifth lens L5 and the image-side diameter D10 of the fourth lens L4 is D11 - D10 = 0.767 mm. The object-side surface curvature radius of the second lens L2 is L2R1=5.405mm, the object-side surface curvature radius of the third lens L3 is L3R1=4.756mm, the focal length f3 of the third lens L3, the focal length f4 of the fourth lens L4 and the focal length f5 of the fifth lens L5 are related by max(abs(f3, f4, f5))=22.877mm, and the focal length f1 of the first lens L1 and the focal length f′ of the telephoto lens are related by f1 / f′=0.640.

[0073] Figure 7 The light aberration diagram of the telephoto lens of Example 2 is shown, with a scale of ±20µm, indicating good aberration correction. Figure 8 The distortion diagram of the telephoto lens of Example 2 is shown, with optical distortion of less than 0.5%, which is very small. Figure 9 The MTF (Modulation Transfer Function) curve of the telephoto lens in Example 2 is shown. The MTF curve illustrates the transmission of image details (i.e., image contrast) at different spatial frequencies by the imaging system. At a spatial frequency of 250 lp / mm, the MTF value is greater than 0.5, indicating excellent resolution. According to... Figures 7 to 9It can be seen that the telephoto lens given in Example 2 has well corrected aberrations, small distortion and good resolution, and can achieve good image quality.

[0074] Example 3

[0075] The following is for reference Figure 10 This describes a telephoto lens according to Embodiment 3 of this application. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted. Figure 10 A schematic diagram of the structure of a telephoto lens according to Embodiment 3 of this application is shown.

[0076] The telephoto lens of Embodiment 3 comprises, from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. An aperture stop STO can be disposed on the object side of the first lens L1. An IR filter is disposed between the fifth lens L5 and the imaging plane IMG.

[0077] The first lens L1 has positive optical power, with a convex object-side surface and a flat image-side surface. The second lens L2 has negative optical power, with a convex object-side surface and a concave image-side surface. The third lens L3 has positive optical power, with a convex object-side surface and a concave image-side surface. The fourth lens L4 has positive optical power, with a convex object-side surface and a convex image-side surface. The fifth lens L5 has negative optical power, with a convex object-side surface and a concave image-side surface. The filter IR has an object-side surface and an image-side surface. Light from the object passes sequentially through the object-side and image-side surfaces of the first lens L1 to the fifth lens L5 and the filter IR, and is finally imaged on the imaging plane IMG.

[0078] Table 5 shows the basic parameters of the telephoto lens in Example 3, where the units for radius of curvature, thickness, focal length, mechanical diameter, and elevation are all millimeters (mm).

[0079] Table 5:

[0080]

[0081] Table 6 shows the higher-order coefficients that can be used for each aspherical mirror in Example 3, wherein each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0082] Table 6:

[0083]

[0084] In Example 3, based on the optical power distribution of the first lens L1 to the fifth lens L5 in the table above, and the reasonable allocation of the optical power, spacing, and refractive index of each lens, a telephoto lens with a long focal length and large aperture can be achieved. Specifically, the focal length f′ of the telephoto lens is 10.7mm, the aperture is f / 2.15, the imaging circle diameter is 7.08mm, and the field of view is 31.7°. The total optical length of existing mobile phone lenses is typically between 3mm and 5mm. In this example, the total optical length of the telephoto lens is 3.6mm, achieving miniaturization of the telephoto lens. Furthermore, all lenses in this example maintain a similar and small mechanical aperture overall, resulting in low tolerance sensitivity, easy processing of each lens, and easy assembly of the lens. The object-side sagitta of the fifth lens L5 is SAG11 = -0.745 mm, and the image-side sagitta of the fifth lens L5 is SAG12 = -0.721 mm, therefore SAG11 - SAG12 = -0.024 mm; the relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 is f1 / |f2| = -1.007; the refractive index of the second lens L2 is N2 = 1.660; the object-side diameter of the third lens L3 is D7 = 3.142 mm, and the image-side diameter of the third lens L3 is D8 = 3.142 mm; the object-side diameter of the fourth lens L4 is D9 = 3.496 mm, and the image-side diameter of the fourth lens L4 is D10 = 3.496 mm; the relationship between the object-side diameter D11 of the fifth lens L5 and the image-side diameter D10 of the fourth lens L4 is D11 - D10 = 0.705 mm. The object-side surface curvature radius of the second lens L2 is L2R1=10.670mm, the object-side surface curvature radius of the third lens L3 is L3R1=4.779mm, the focal length f3 of the third lens L3, the focal length f4 of the fourth lens L4 and the focal length f5 of the fifth lens L5 are related by max(abs(f3,f4,f5))=381.467mm, and the focal length f1 of the first lens L1 and the focal length f′ of the telephoto lens are related by f1 / f′=0.573.

[0085] Figure 11 The light aberration diagram of the telephoto lens of Example 3 is shown, with a scale of ±20µm, indicating good aberration correction. Figure 12 The distortion diagram of the telephoto lens of Example 3 is shown, with optical distortion of less than 0.5%, which is very small. Figure 13 The MTF (Modulation Transfer Function) curve of the telephoto lens in Example 3 is shown. The MTF curve illustrates the transmission of image details (i.e., image contrast) at different spatial frequencies by the imaging system. At a spatial frequency of 250 lp / mm, the MTF value is greater than 0.19, indicating excellent resolution. According to... Figures 11 to 13It can be seen that the telephoto lens given in Example 3 has well corrected aberrations, small distortion and good resolution, and can achieve good imaging quality.

[0086] In summary, Examples 1, 2, and 3 satisfy the relationships shown in Table 7.

[0087] Table 7:

[0088]

[0089] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A telephoto lens, characterized in that, It consists of a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from the object side to the image side; The first lens has a positive optical power. The object side surface of the first lens is convex, and the image side surface is flat; The second lens has a negative optical power. The object side surface of the second lens is convex, and the image side surface is concave, and the radius of curvature L2R1 of the object side surface of the second lens satisfies 5 mm < L2R1 < 15 mm; The third lens has a positive optical power. The object side surface of the third lens is convex, and the image side surface is concave, and the radius of curvature L3R1 of the object side surface of the third lens satisfies 3 mm < L3R1 < 11 mm; The fourth lens has a positive optical power. The object side surface of the fourth lens is convex or concave, and the image side surface is convex; The fifth lens has a negative optical power. The object side surface of the fifth lens is convex, and the image side surface is concave. The object side surface of the fifth lens is convex near the axis, and the image side surface of the fifth lens is concave near the axis, and at least one of the object side surface and the image side surface of the fifth lens has at least one inflection point; The sagittal height SAG11 of the object side surface of the fifth lens and the sagittal height SAG12 of the image side surface of the fifth lens satisfy: -1 mm < SAG11 < -0.3 mm, -1 mm < SAG12 < -0.2 mm, -0.8 mm < SAG11 - SAG12 < 0 mm; The diameter D11 of the object side surface of the fifth lens and the diameter D10 of the image side surface of the fourth lens satisfy: 0.5 mm < D11 - D10 < 0.85 mm.

2. The telephoto lens according to claim 1, characterized in that, The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.7 < f1 / |f2| < 1.

3.

3. The telephoto lens according to claim 2, characterized in that, The refractive index N2 of the second lens satisfies: 1.6 < N2.

4. The telephoto lens according to claim 1, characterized in that, The diameter D7 of the object side surface of the third lens and the diameter D8 of the image side surface of the third lens satisfy: 2.8 mm < D 5. The telephoto lens according to claim 1, characterized in that, ​ 6. The telephoto lens according to claim 1, characterized in that, ​ 7. The telephoto lens according to claim 1, characterized in that, ​ 8. An electronic device, characterized in that, ​

Images