Telephoto lens and electronic equipment

Abstract

The invention discloses a telephoto lens and electronic equipment. The telephoto lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object side to an image side, the first lens has positive focal power, and the object side surface of the first lens is a convex surface; the second lens has negative focal power, and the curvature radius L2R1 of the object side surface of the second lens meets 5 mmlt; l2R1lt; L2R1lt; the thickness is 15 mm; the third lens has positive focal power, and the curvature radius L3R1 of the object side surface of the third lens meets 3mm lt; l3R1lt; L3R1lt; 11 mm; the fourth lens has positive focal power; the fifth lens has negative focal power, the object side surface of the fifth lens is a convex surface at a paraxial position, the image side surface of the fifth lens is a concave surface at a paraxial position, and at least one of the object side surface and the image side surface of the fifth lens has at least one inflection point. According to the telephoto lens and the electronic equipment, the lens is miniaturized, the aperture is large, and the resolution is good.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging, 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 volume, 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. The present invention provides a telephoto lens, which 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 focal power, and the object side surface of the first lens is a convex surface; the second lens has a negative focal 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 focal 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 focal power; the fifth lens has a negative focal power, the object side surface of the fifth lens is convex in the paraxial region, the image side surface of the fifth lens is concave in 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.

[0004] Optionally, 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.

[0005] 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.

[0006] Optionally, the refractive index N2 of the second lens satisfies: 1.6 < N2.

[0007] Optionally, 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 < D7 < 3.5 mm, 2.8 mm < D8 < 3.6 mm.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] Optionally, the telephoto lens further includes a diaphragm, and the diaphragm is disposed on the object side surface of the first lens.

[0013] Optionally, the telephoto lens further includes a filter, and the filter is disposed between the fifth lens and the imaging surface.

[0014] The present invention also provides an electronic device including the above-mentioned telephoto lens.

[0015] 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 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 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 incident angle of the principal ray. According to the optical power distribution of the first lens to the fifth lens, 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. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic structural diagram of a telephoto lens according to an embodiment of the present application is shown.

[0018] Figure 2 A schematic structural diagram of a telephoto lens according to Embodiment 1 of the present application is shown.

[0019] Figures 3 to 5 The light aberration diagram, distortion diagram and MTF curve diagram of the telephoto lens of Example 1 are respectively shown.

[0020] Figure 6 A schematic structural diagram of a telephoto lens according to Embodiment 2 of the present application is shown.

[0021] Figures 7 to 9 The light aberration diagram, distortion diagram and MTF curve diagram of the telephoto lens of Example 2 are respectively shown.

[0022] Fig.10 A schematic structural diagram of a telephoto lens according to Embodiment 3 of the present application is shown.

[0023] Figures 11 to 13 The light aberration diagram, distortion diagram and MTF curve diagram of the telephoto lens of Example 3 are respectively shown. DETAILED DESCRIPTION

[0024] The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the drawings. Through the description of the specific implementation methods, the technical means and effects adopted by the present invention to achieve the intended purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and illustration purposes, and are not used to limit the present invention. Some well-known parts may not be shown. In each of the drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the drawings are not necessarily drawn strictly in accordance with the actual proportions.

[0025] It should be understood that the terms "first", "second", "third", "fourth", etc. are only used to distinguish components or circuits with similar properties, rather than indicating or implying relative importance or a specific order. The terms "include", "comprises", or any other variation thereof, are intended to cover non-exclusive inclusion, and may include other elements not explicitly listed in addition to those listed elements.

[0026] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0027] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface 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 position of the concave surface 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 object is called the object side of the lens, and the surface of each lens closest to the imaging plane IMG is called the image side of the lens.

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] The features, principles and other aspects of the present application are described in detail below.

[0030] Figure 1 A schematic structural diagram of a telephoto lens according to an embodiment of the present application is shown.

[0031] The telephoto lens according to an exemplary embodiment of the present application includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 from the object side to the image side; the first lens L1 has a positive optical power, and the object side surface of the first lens L1 is a convex surface; 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 aberration correction. 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 distributing the optical power, spacing, and refractive index of each lens, the miniaturization of the lens, large aperture, and good resolution can be achieved. At the same time, by satisfying the shapes of the respective lenses, 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.

[0032] 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, -0.8 mm < SAG11 - SAG12 < 0 mm can be satisfied, where the sag of the object side surface of the fifth lens L5 is SAG11, and the sag of the image side surface of the fifth lens L5 is SAG12. By satisfying -1 mm < SAG11 < -0.3 mm, -1 mm < SAG12 < -0.2 mm, -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.

[0033] In an exemplary embodiment, for the telephoto lens according to the present application, 0.7 < f1 / |f2| < 1.3 can be satisfied, where the focal length of the first lens L1 is f1, and the focal length of the second lens L2 is f2. 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 the resolution.

[0034] In one exemplary embodiment, for the telephoto lens according to the present application, it further satisfies 1.6 < N2, where N2 is the refractive index of the second lens L2. By 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, satisfying 0.7 < f1 / |f2| < 1.3 and 1.6 < N2, it is more beneficial to correct spherical aberration and improve the resolution.

[0035] In an exemplary embodiment, for the telephoto lens according to the present application, it can satisfy 2.8 mm < D7 < 3.5 mm, 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 controlling the object-side diameter D7 and the image-side diameter D8 of the third lens L3, satisfying 2.8 mm < D7 < 3.5 mm, 2.8 mm < D8 < 3.6 mm, it is beneficial to correct the off-axis field aberration, improve the 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.

[0036] In an exemplary embodiment, for the telephoto lens according to the present application, it can satisfy 3.2 mm < D9 < 3.7 mm, 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 controlling the object-side diameter D9 and the image-side diameter D10 of the fourth lens L4, satisfying 3.2 mm < D9 < 3.7 mm, 3.3 mm < D10 < 3.7 mm, it is beneficial to correct the off-axis field aberration, improve the 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, for the telephoto lens according to the present application, it can 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 the object-side diameter D11 of the fifth lens L5 and the image-side diameter D10 of the fourth lens L4, satisfying 0.5 mm < D11 - D10 < 0.85 mm, it is beneficial to correct the off-axis field aberration and improve the resolution.

[0038] In one exemplary embodiment, for the telephoto lens according to the present application, the following can be satisfied: 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 correct the off-axis field aberration and improve the resolution.

[0039] In an exemplary embodiment, for the telephoto lens according to the present application, the following can be satisfied: 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.

[0040] In an exemplary embodiment, for the telephoto lens according to the present application, the following can be satisfied: 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.

[0041] In an exemplary embodiment, for the mobile phone lens according to the present application, the mobile phone lens further includes a diaphragm STO, and the diaphragm STO can be disposed on the object side of the first lens L1 or between adjacent lenses.

[0042] In an exemplary embodiment, for the mobile phone lens according to the present application, the mobile phone lens 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. The filter IR can be disposed between the fifth lens L5 and the imaging surface IMG.

[0043] Based on the same inventive concept, according to an exemplary embodiment of the present application, the electronic device includes the telephoto lens described above. The electronic device includes but is not limited to a smartphone, a tablet computer, a laptop computer, a PTZ camera, a surveillance camera, and other imaging devices. The implementation of the electronic device can refer to the embodiment of the telephoto lens, and the repetitions will not be repeated.

[0044] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the optical imaging lens can be changed to obtain the various results and advantages described in this specification. 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 necessary, the optical imaging lens may also include other numbers of lenses.

[0045] Specific embodiments of the telephoto lens applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings.

[0046] Example 1 The following reference Figure 2 A telephoto lens according to Embodiment 1 of the present application is described. Figure 2 A schematic diagram of an equivalent replacement optical structure of a telephoto lens according to Embodiment 1 of the present application is shown.

[0047] The telephoto lens of Example 1 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. A stop STO may be disposed on the object side of the first lens L1. A filter IR is disposed between the fifth lens L5 and the imaging surface IMG.

[0048] The first lens L1 has positive focal power, its object side surface is convex, and its image side surface is a plane. The second lens L2 has negative focal power, its object side surface is convex, and its image side surface is concave. The third lens L3 has positive focal power, its object side surface is convex, and its image side surface is concave. The fourth lens L4 has positive focal power, its object side surface is convex, and its image side surface is convex. The fifth lens L5 has negative focal power, its object side surface is convex, and its image side surface is concave. The filter IR has an object side surface and an image side surface. The light from the object passes through the object side surface and the image side surface of the first lens L1 to the fifth lens L5 and the filter IR in sequence, and is finally imaged on the imaging surface IMG.

[0049] Table 1 shows the basic parameters of the telephoto lens of Example 1, wherein the units of the curvature radius, thickness, focal length, mechanical aperture and sagittal height are all in millimeters (mm).

[0050] Table 1:

[0051] Among them, 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.

[0052] In Embodiment 1, the object side surface and the image side surface of any lens among the first lens L1 to the fifth lens L5 are both even-order aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula: (1) Wherein, Z represents the height in the optical axis direction, c is the inverse of the surface radius, k is the cone coefficient, r is the diameter in the radial direction; α represents the aspheric coefficient, α1 represents the aspheric coefficient A2, α2 represents the aspheric coefficient A4... Table 2 shows the high-order coefficients A2, A4, A6, A8, A10, A12, A14 and A16 that can be used for each aspheric mirror surface in Example 1.

[0053] Table 2:

[0054] In Example 1, according to the focal power distribution of the first lens L1 to the fifth lens L5 in the above table, the focal power, spacing and refractive index of each lens are reasonably allocated and set, the telephoto and large aperture of the telephoto lens can be achieved, wherein the focal length f′ of the telephoto lens is 10.69 mm, the aperture of the telephoto lens is 2.14, the imaging circle diameter of the telephoto lens is 7.06 mm, and the field of view angle of the telephoto lens is 31.7°. The total optical length of existing mobile phone lenses is usually between 3 mm and 5 mm. The total optical length of the telephoto lens in this embodiment is 3.6 mm, which realizes the miniaturization of the telephoto lens. At the same time, the lenses of this embodiment maintain similar and small mechanical apertures as a whole, the tolerance sensitivity of the lenses is low, each lens is easy to process, and the lenses are easy to assemble. The object side sag of the fifth lens L5 is SAG11=-0.548mm, and the image side sag of the fifth lens L5 is SAG12=-0.500mm, then SAG11-SAG12=-0.048mm; 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=3.388mm, the image side diameter of the third lens L3 is D8=3.388mm, the object side diameter of the fourth lens L4 is D9=3.481mm, the image side diameter of the fourth lens L4 is D10=3.481mm, 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=0.667mm. The object side surface curvature radius L2R1 of the second lens L2 is 6.187 mm, the object side surface curvature radius L3R1 of the third lens L3 is 6.783 mm, 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))=42.288 mm, 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.

[0055] Figure 3 The light aberration diagram of the telephoto lens of Example 1 is shown, and the graph ratio is ±20um, and the aberration correction is good. Figure 4 The distortion diagram of the telephoto lens of Example 1 is shown, and the optical distortion is less than 0.5%, which is very small. Figure 5 The MTF curve of the telephoto lens of Example 1 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of image details (i.e., image contrast) of the imaging system at different spatial frequencies. The MTF value is greater than 0.2 at a spatial frequency of 250lp / mm, which has good resolution. Figures 3 to 5It can be seen that the telephoto lens provided in Example 1 has well-corrected aberrations, small distortion and good resolution, and can achieve good imaging quality.

[0056] Example 2 The following reference Figure 6 A telephoto lens according to Embodiment 2 of the present application is described. In this embodiment, for the sake of brevity, some descriptions similar to Embodiment 1 are omitted. Figure 6 A schematic structural diagram of a telephoto lens according to Embodiment 2 of the present application is shown.

[0057] The telephoto lens of Example 2 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5 in order from the object side to the image side. The aperture STO may be disposed on the object side of the first lens L1. The filter IR is disposed between the fifth lens L5 and the imaging surface IMG.

[0058] The first lens L1 has positive focal power, its object side surface is convex, and its image side surface is flat. The second lens L2 has negative focal power, its object side surface is convex, and its image side surface is concave. The third lens L3 has positive focal power, its object side surface is convex, and its image side surface is concave. The fourth lens L4 has positive focal power, its object side surface is concave, and its image side surface is convex. The fifth lens L5 has negative focal power, its object side surface is convex, and its image side surface is concave. The filter IR has an object side surface and an image side surface. The light from the object passes through the object side surface and the image side surface of the first lens L1 to the fifth lens L5 and the filter IR in sequence, and is finally imaged on the imaging surface IMG.

[0059] Table 3 shows the basic parameters of the telephoto lens of Example 2, wherein the units of the radius of curvature, thickness, focal length, mechanical aperture and sagittal height are all in millimeters (mm).

[0060] Table 3:

[0061] Table 4 shows the high-order coefficients of each aspherical mirror surface that can be used in Example 2, wherein each aspherical surface shape can be defined by the formula (1) given in the above-mentioned Example 1.

[0062] Table 4:

[0063] In Example 2, according to the focal power distribution of the first lens L1 to the fifth lens L5 in the above table, the focal power, spacing and refractive index of each lens are reasonably allocated and arranged, the telephoto and large aperture of the telephoto lens can be achieved, wherein the focal length f′ of the telephoto lens is 10.7 mm, the aperture of the telephoto lens is 2.14, the imaging circle diameter of the telephoto lens is 6.89 mm, and the field of view angle of the telephoto lens is 31.7°. The total optical length of existing mobile phone lenses is usually between 3 mm and 5 mm. The total optical length of the telephoto lens in this embodiment is 3.7 mm, which realizes the miniaturization of the telephoto lens. At the same time, the lenses of this embodiment maintain similar and small mechanical apertures as a whole, the tolerance sensitivity of the lenses is low, each lens is easy to process, and the lenses are easy to assemble. The object side sag of the fifth lens L5 is SAG11=-0.416mm, and the image side sag of the fifth lens L5 is SAG12=-0.212mm, then SAG11-SAG12=-0.204mm; 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=3.370mm, the image side diameter of the third lens L3 is D8=3.370mm, the object side diameter of the fourth lens L4 is D9=3.433mm, the image side diameter of the fourth lens L4 is D10=3.433mm, 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=0.767mm. The object side surface curvature radius L2R1 of the second lens L2 is 5.405 mm, the object side surface curvature radius L3R1 of the third lens L3 is 4.756 mm, 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))=22.877 mm, 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.

[0064] Figure 7 The light aberration diagram of the telephoto lens of Example 2 is shown, and the graph ratio is ±20um, and the aberration correction is good. Figure 8 The distortion diagram of the telephoto lens of Example 2 is shown, and the optical distortion is less than 0.5%, which is very small. Fig. 9 The MTF curve of the telephoto lens of Example 2 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of image details (i.e., image contrast) of the imaging system at different spatial frequencies. The MTF value is greater than 0.5 at a spatial frequency of 250lp / mm, which has good resolution. Figures 7 to 9It can be seen that the telephoto lens provided in Example 2 has well-corrected aberrations, small distortion and good resolution, and can achieve good imaging quality.

[0065] Example 3 The following reference Fig.10 A telephoto lens according to Embodiment 3 of the present application is described. In this embodiment, for the sake of brevity, some descriptions similar to Embodiment 1 will be omitted. Fig.10 A schematic structural diagram of a telephoto lens according to Embodiment 3 of the present application is shown.

[0066] The telephoto lens of Example 3 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5 in order from the object side to the image side. The aperture STO may be disposed on the object side of the first lens L1. The filter IR is disposed between the fifth lens L5 and the imaging surface IMG.

[0067] The first lens L1 has positive focal power, its object side surface is convex, and its image side surface is a plane. The second lens L2 has negative focal power, its object side surface is convex, and its image side surface is concave. The third lens L3 has positive focal power, its object side surface is convex, and its image side surface is concave. The fourth lens L4 has positive focal power, its object side surface is convex, and its image side surface is convex. The fifth lens L5 has negative focal power, its object side surface is convex, and its image side surface is concave. The filter IR has an object side surface and an image side surface. The light from the object passes through the object side surface and the image side surface of the first lens L1 to the fifth lens L5 and the filter IR in sequence, and is finally imaged on the imaging surface IMG.

[0068] Table 5 shows the basic parameters of the telephoto lens of Example 3, wherein the units of the radius of curvature, thickness, focal length, mechanical aperture and sagittal height are all in millimeters (mm).

[0069] Table 5:

[0070] Table 6 shows the high-order coefficients of each aspherical mirror surface that can be used in Example 3, wherein each aspherical surface shape can be defined by the formula (1) given in the above Example 1.

[0071] Table 6:

[0072] In Example 3, according to the focal power distribution of the first lens L1 to the fifth lens L5 in the above table, the focal power, spacing and refractive index of each lens are reasonably allocated and set, the telephoto and large aperture of the telephoto lens can be achieved, wherein the focal length f′ of the telephoto lens is 10.7 mm, the aperture of the telephoto lens is 2.15, the imaging circle diameter of the telephoto lens is 7.08 mm, and the field of view angle of the telephoto lens is 31.7°. The total optical length of existing mobile phone lenses is usually between 3 mm and 5 mm. The total optical length of the telephoto lens in this embodiment is 3.6 mm, which realizes the miniaturization of the telephoto lens. At the same time, the lenses of this embodiment maintain similar and small mechanical apertures as a whole, the tolerance sensitivity of the lenses is low, the lenses are easy to process, and the lenses are easy to assemble. The object side sag of the fifth lens L5 is SAG11=-0.745mm, and the image side sag of the fifth lens L5 is SAG12=-0.721mm, then SAG11-SAG12=-0.024mm; 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=3.142mm, the image side diameter of the third lens L3 is D8=3.142mm, the object side diameter of the fourth lens L4 is D9=3.496mm, the image side diameter of the fourth lens L4 is D10=3.496mm, 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=0.705mm. The object side surface curvature radius L2R1 of the second lens L2 is 10.670 mm, the object side surface curvature radius L3R1 of the third lens L3 is 4.779 mm, 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))=381.467 mm, 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.

[0073] Fig.11 The light aberration diagram of the telephoto lens of Example 3 is shown, and the graph ratio is ±20um, and the aberration correction is good. Fig.12 The distortion diagram of the telephoto lens of Example 3 is shown, and the optical distortion is less than 0.5%, which is very small. Fig.13 The MTF curve of the telephoto lens of Example 3 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of image details (i.e., image contrast) of the imaging system at different spatial frequencies. The MTF value is greater than 0.19 at a spatial frequency of 250lp / mm, which has good resolution. Figures 11 to 13It can be seen that the telephoto lens provided in Example 3 has well-corrected aberrations, small distortion and good resolution, and can achieve good imaging quality.

[0074] In summary, Example 1, Example 2 and Example 3 respectively satisfy the relationship shown in Table 7.

[0075] Table 7:

[0076] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A telephoto lens, characterized in that: From the object side to the image side, it includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens; The first lens has positive optical power, and the object side surface of the first lens is convex; The second lens has a negative optical power, and the object side curvature radius L2R1 of the second lens satisfies 5 mm. <L2R1<15mm; The third lens has positive focal power, and the object side curvature radius L3R1 of the third lens satisfies 3mm <L3R1<11mm; The fourth lens has positive refractive power; The fifth lens has negative optical power, the object side surface of the fifth lens is convex at the paraxial position, the image side surface of the fifth lens is concave at the paraxial position, and at least one of the object side surface and the image side surface of the fifth lens has at least one inflection point.

2. The telephoto lens according to claim 1, characterized in that: The object side sag height SAG11 of the fifth lens and the image side sag height SAG12 of the fifth lens satisfy: -1 mm <SAG11<-0.3mm,-1mm<SAG12<-0.2mm,-0.8mm<SAG11-SAG12<0mm。 3. 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。 4. The telephoto lens according to claim 3, characterized in that: The refractive index N2 of the second lens satisfies: 1.6 <N2。 5. The telephoto lens according to claim 1, characterized in that: The object side diameter D7 of the third lens and the image side diameter D8 of the third lens satisfy: 2.8 mm <D7<3.5mm,2.8mm<D8<3.6mm。 6. The telephoto lens according to claim 1, wherein: The object side diameter D9 of the fourth lens and the image side diameter D10 of the fourth lens satisfy: 3.2 mm <D9<3.7mm,3.3mm<D10<3.7mm。 7. The telephoto lens according to claim 1, wherein: 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<0.85mm。 8. The telephoto lens according to claim 1, wherein: 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))<1000mm。 9. The telephoto lens according to claim 1, wherein: The focal length f1 of the first lens and the focal length f′ of the telephoto lens satisfy: 0.45 <f1 / f′<0.75。 10. An electronic device, characterized in that: Comprising the telephoto lens as claimed in any one of claims 1 to 9.

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