Telephoto lens

Abstract

The telephoto lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from an object plane to an image plane along an optical axis, the first lens is a positive-focal-power lens, the second lens is a positive-focal-power lens, the third lens is a positive-focal-power lens, the fourth lens is a positive-focal-power lens, and the fifth lens is a negative-focal-power lens. The fourth lens is a negative focal power lens, and the fifth lens is a positive focal power lens. With the adoption of the technical scheme, the telephoto lens comprises five lenses, and the focal power of each lens is reasonably distributed, so that aberration can be well corrected, distortion can be well reduced, enough good image quality can be ensured while the focal length is long, and the miniaturized telephoto lens can be realized.

Description

Technical Field

[0001] The embodiment of the utility model relates to the technical field of optical devices, and in particular to a telephoto lens. Background Art

[0002] With the rapid development of optical systems, the quality of telephoto lenses is becoming increasingly demanded. In order to be able to cope with more measurements, a lens with a long focal length, short total length, clear imaging, and less distortion is generally required. Utility Model Content

[0003] The utility model provides a telephoto lens, which can realize a lens with long focal length, short total length and good imaging quality.

[0004] The embodiment of the utility model provides a telephoto lens, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object plane to the image plane along the optical axis;

[0005] The first lens is a positive power lens, the second lens is a positive power lens, the third lens is a positive power lens, the fourth lens is a negative power lens, and the fifth lens is a positive power lens.

[0006] Optionally, the center thickness of the first lens is T1, the center thickness of the second lens is T2, the center thickness of the third lens is T3, the center thickness of the fourth lens is T4, the center thickness of the fifth lens is T5, and the sum of the center thicknesses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens is ALT;

[0007] The air gap between the center of the first lens and the center of the second lens is G12, the air gap between the center of the second lens and the center of the third lens is G23, the air gap between the center of the third lens and the center of the fourth lens is G34, and the sum of the air gap between the center of the first lens and the center of the second lens, the air gap between the center of the second lens and the center of the third lens, and the air gap between the center of the third lens and the center of the fourth lens is AAG;

[0008] Among them, (T1+T2) / T3≧0.60;

[0009] (T3+G34+T5) / (G12+T2+G23)≧1.00;

[0010] (T1+G23) / (G12+G34)≧0.20;

[0011] G34 / (T2+T4)≦0.27;

[0012] ALT / (T1+G12)≦3.30;

[0013] ALT / (G23+T4)≧9.00;

[0014] (G34+T4+T5) / T2≦2.20;

[0015] (T1+T5) / T2≦2.00;

[0016] AAG / (T5+G34)≦1.20.

[0017] Optionally, the total optical length of the telephoto lens is TTL, the back focus of the telephoto lens is BFL, the focal length of the telephoto lens is EFL, and the aperture number of the telephoto lens is Fno;

[0018] Where: TTL / (G23+T3+G34+T4)≧2.40;

[0019] TTL / (G23+G34+T4)≧9.00;

[0020] TTL / (T1+T3+G34)≦5.10;

[0021] AAG / BFL≧0.35;

[0022] ALT / (T2+BFL)≧1.00;

[0023] (EFL+BFL) / Fno≧3.80;

[0024] (G12+G23+EFL) / (T3+T5)≧1.19;

[0025] EFL / (G23+T3+G34)≧1.00.

[0026] Optionally, the half image height of the telephoto lens is ImgH, the back focus of the telephoto lens is BFL, the field of view angle corresponding to the half image height of the telephoto lens is HFOV, and the total optical length of the telephoto lens is TTL;

[0027] Among them, ImgH / BFL≧0.69;

[0028] HFOV / (T3+T4+T5)≦10.00;

[0029] HFOV / TTL≦3.10.

[0030] Optionally, the Abbe coefficient of the first lens is V1, the Abbe coefficient of the second lens is V2, the Abbe coefficient of the third lens is V3, the Abbe coefficient of the fourth lens is V4, and the Abbe coefficient of the fifth lens is V5;

[0031] Among them: V1+V2+V5≧130;

[0032] V2+V3+V4+V5≦220;

[0033] V1+V3+V5≦200;

[0034] |V2-V5|≦40;

[0035] |V3-V5|≧6.

[0036] Optionally, the first lens includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, and the second lens includes a second object-side surface close to the object plane and a second image-side surface close to the image plane;

[0037] The first object-side surface is a convex surface, the first image-side surface is a concave surface, and the first lens is a meniscus lens;

[0038] The second object-side surface is a concave surface, the second image-side surface is a convex surface, and the second lens is a meniscus lens.

[0039] Optionally, the first lens includes an aspherical plastic lens;

[0040] The second lens comprises an aspherical plastic lens;

[0041] The third lens comprises a spherical glass lens;

[0042] The fourth lens comprises an aspherical plastic lens;

[0043] The fifth lens includes an aspherical plastic lens.

[0044] Optionally, the fourth lens and the fifth lens are glued together.

[0045] Optionally, the focal length EFL of the telephoto lens satisfies 3mm≤EFL≤4mm;

[0046] The total optical length TTL of the telephoto lens satisfies TTL≦14.50.

[0047] Optionally, the telephoto lens further includes an aperture and a filter;

[0048] The aperture is arranged in the optical path between the second lens and the third lens;

[0049] The filter is arranged in the optical path between the fifth lens and the image plane.

[0050] The telephoto lens provided in the embodiment of the utility model is provided with five lenses, and the optical focal lengths of the first lens to the fifth lens are respectively set to be positive focal length, positive focal length, positive focal length, negative focal length and positive focal length. By coordinating the optical focal lengths of the various lenses, a design of a low-cost telephoto lens that can take into account both imaging requirements and small distortion is finally achieved.

[0051] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0053] Figure 1 This is a schematic structural diagram of a telephoto lens provided in Embodiment 1 of the present utility model;

[0054] Figure 2 This is a schematic diagram of a spherical aberration curve of a telephoto lens provided in the first embodiment of the utility model;

[0055] Figure 3 This is a schematic diagram of field curvature distortion of a telephoto lens provided in the first embodiment of the utility model;

[0056] Figure 4 This is a schematic diagram of a chromatic aberration curve of a telephoto lens provided in the first embodiment of the present utility model;

[0057] Figure 5 This is a schematic diagram of the structure of a telephoto lens provided in Embodiment 2 of the present utility model;

[0058] Figure 6 This is a schematic diagram of a spherical aberration curve of a telephoto lens provided in the second embodiment of the present utility model;

[0059] Figure 7 This is a schematic diagram of field curvature distortion of a telephoto lens provided in the second embodiment of the present utility model;

[0060] Figure 8 This is a schematic diagram of a chromatic aberration curve of a telephoto lens provided in the second embodiment of the present utility model;

[0061] Fig. 9 This is a schematic structural diagram of a telephoto lens provided in Embodiment 3 of the present utility model;

[0062] Fig.10 This is a schematic diagram of a spherical aberration curve of a telephoto lens provided in Embodiment 3 of the present utility model;

[0063] Fig.11 This is a schematic diagram of field curvature distortion of a telephoto lens provided in Embodiment 3 of the present utility model;

[0064] Fig.12 This is a schematic diagram of a chromatic aberration curve of a telephoto lens provided in Embodiment 3 of the present utility model. DETAILED DESCRIPTION

[0065] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0066] Embodiment 1

[0067] Figure 1 Schematic diagram of the structure of a telephoto lens provided in the first embodiment of the present utility model. Figure 1 As shown, the telephoto lens provided in the first embodiment of the present invention comprises a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150 which are arranged in sequence from the object plane to the image plane along the optical axis; wherein the first lens 110 is a positive power lens, the second lens 120 is a positive power lens, the third lens 130 is a positive power lens, the fourth lens 140 is a negative power lens, and the fifth lens 150 is a positive power lens.

[0068] Specifically, the telephoto lens provided by the embodiment of the utility model includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150, a total of five lenses with optical focal length. The number of lenses is relatively small, which is conducive to realizing a miniaturized and low-cost telephoto lens.

[0069] Furthermore, the focal length is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group). The first lens 110, the second lens 120, and the third lens 130 are all set to be positive focal length lenses. The first lens 110, the second lens 120, and the third lens 130 can play a role in converging light to ensure that as much light as possible incident on the lens is collected, which is beneficial to improving the lens illumination. Furthermore, the first lens 110, the second lens 120 and the third lens 130 are all positive power lenses, which can significantly correct the edge aberration of the optical system, thereby improving the imaging resolution of the optical system. The fourth lens 140 is set as a negative power lens, and the fourth lens 140 can effectively deflect the light incident thereon, thereby effectively increasing the field of view of the telephoto lens. The fifth lens 150 is set as a positive power lens, so that the fifth lens 150 can timely correct the larger aberration generated by the fourth lens 140, which can ensure the aberration balance and high and low temperature performance stability of the lens while eliminating the high-order aberration of the lens as much as possible, and at the same time can control the target surface (size) and improve the image quality of the lens to meet the use requirements in more situations. The telephoto lens provided by the embodiment of the utility model is cross-set by positive and negative power, so that the positive and negative focusing cancel each other out, which can reduce temperature drift and improve the performance of the telephoto lens.

[0070] Based on the above embodiment, the first lens 110 includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, and the second lens 120 includes a second object-side surface close to the object plane and a second image-side surface close to the image plane; the first object-side surface is a convex surface, the first image-side surface is a concave surface, and the first lens is a meniscus lens; the second object-side surface is a concave surface, the second image-side surface is a convex surface, and the second lens is a meniscus lens.

[0071] Specifically, the object side of the lens can be understood as the surface of the lens close to the object plane, and the image side of the lens can be understood as the surface of the lens close to the image plane. Specifically, the object side of the first lens 110 is a convex surface, and the image side is a concave surface, which can be understood as the object side of the first lens 110 is convex toward the object plane at the near optical axis position, and the image side is concave toward the image plane at the near optical axis position, that is, the first lens 110 is a lens with a convex-concave structure. The object side of the second lens 120 is a concave surface, and the image side is a convex surface, which can be understood as the object side of the second lens 120 is concave toward the object plane at the near optical axis position, and the image side is convex toward the image plane at the near optical axis position, that is, the second lens 120 is a lens with a concave-convex structure.

[0072] The object side surface of the first lens 110 is set to be convex toward the object plane at the near optical axis position, so as to collect as much light incident on the lens as possible, which is beneficial to improving the lens illumination. The image side surface of the first lens 120 is a concave surface, so that the light enters the rear lens smoothly, reducing the sensitivity of the system. At the same time, the design of the concave surface also greatly facilitates the structural design. The object side surface of the second lens 120 is set to be concave toward the object plane at the near optical axis position, so as to ensure that the second lens 120 can smoothly receive the light emitted by the first lens, reduce the deflection degree, and reduce the sensitivity. In addition, the first lens 110 and the second lens 120 are both meniscus lenses, and the first lens 120 and the rear second lens 120 form a symmetrical optical system, thereby shortening the lens length, facilitating the realization of miniaturized lens settings, and simplifying the lens assembly process.

[0073] Based on the above embodiment, the center thickness of the first lens 110 is T1, the center thickness of the second lens 120 is T2, the center thickness of the third lens 130 is T3, the center thickness of the fourth lens 140 is T4, the center thickness of the fifth lens 150 is T5, and the sum of the center thicknesses of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140 and the fifth lens 150 is ALT; the air gap between the center of the first lens 110 and the center of the second lens 120 is G12, the air gap between the center of the second lens 120 and the center of the third lens 130 is G23, the air gap between the center of the third lens 130 and the center of the fourth lens 140 is G34, and the sum of the air gap between the center of the first lens 110 and the center of the second lens 120, the air gap between the center of the second lens 120 and the center of the third lens 130, and the air gap between the center of the third lens 130 and the center of the fourth lens 140 is AAG; wherein, (T1+T2) / T3≧0.60;

[0074] (T3+G34+T5) / (G12+T2+G23)≧1.00; (T1+G23) / (G12+G34)≧0.20;

[0075] G34 / (T2+T4)≦0.27; ALT / (T1+G12)≦3.30; ALT / (G23+T4)≧9.00;

[0076] (G34+T4+T5) / T2≦2.20; (T1+T5) / T2≦2.00; AAG / (T5+G34)≦1.20.

[0077] Specifically, the center thickness of the lens can be understood as the thickness of the lens in the direction of the optical axis, and the air gap between the centers of two adjacent lenses can be understood as the air gap between two adjacent lenses in the direction of the optical axis. By setting the center thickness of each lens and the air gap between two adjacent lenses, the thickness ratio of each lens can be guaranteed, unreasonable lens shapes can be avoided, and the processing and molding of each lens can be facilitated. Furthermore, by setting the center thickness of each lens and the air gap between two adjacent lenses, it is helpful to reduce the difficulty of assembling the entire lens.

[0078] Based on the above embodiment, the total optical length of the telephoto lens is TTL, the back focus of the telephoto lens is BFL, the focal length of the telephoto lens is EFL, and the aperture number of the telephoto lens is Fno;

[0079] Among them: TTL / (G23+T3+G34+T4)≧2.40; TTL / (G23+G34+T4)≧9.00;

[0080] TTL / (T1+T3+G34)≦5.10; AAG / BFL≧0.35; ALT / (T2+BFL)≧1.00;

[0081] (EFL+BFL) / Fno≧3.80; (G12+G23+EFL) / (T3+T5)≧1.19;

[0082] EFL / (G23+T3+G34)≧1.00.

[0083] Specifically, the total optical length of the lens can be understood as the distance between the center of the object side surface of the first lens 110 and the center of the image side surface of the fifth lens 150, and the back focus of the lens can be understood as the distance between the center of the image side surface of the fifth lens 150 and the center of the image plane. By reasonably setting the distance between the total optical length of the lens and the center thickness of each lens and the air interval between the centers of two adjacent lenses, and by reasonably setting the center thickness of each lens and the air interval between two adjacent lenses, it can be ensured that the telephoto lens has a reasonable total optical length, while ensuring the miniaturization of the telephoto lens, the assembly yield is improved and the cost is reduced. By reasonably setting the relationship between the back focus of the lens and the sum of the air gaps in the telephoto lens group and the sum of the center thickness of the lens, it can be ensured that the telephoto lens has a reasonable optical back focus, which is conducive to improving the assembly yield and reducing the cost. By reasonably setting the relationship between the focal length of the telephoto lens and the optical back focus, the aperture number, the center thickness of each lens and the air interval between the centers of two adjacent lenses, and by reasonably setting the center thickness of each lens and the air interval between two adjacent lenses, it can be ensured that the lens has a longer focal length and achieves telephoto performance.

[0084] On the basis of the above embodiment, the half image height in the telephoto lens is ImgH, the back focus of the telephoto lens is BFL, the field of view angle corresponding to the half image height in the telephoto lens is HFOV, and the total optical length of the telephoto lens is TTL; wherein, ImgH / BFL≧0.69; HFOV / (T3+T4+T5)≦10.00; HFOV / TTL≦3.10. By limiting the half image height in the telephoto lens and the back focus to satisfy the above corresponding relationship, the field of view angle corresponding to the half image height and the center thickness of each lens to satisfy the above corresponding relationship, and the field of view angle corresponding to the half image height and the total optical length to satisfy the above corresponding relationship, it can be ensured that the telephoto lens has a good imaging effect and a large field of view angle.

[0085] Based on the above embodiment, the Abbe coefficient of the first lens 110 is V1, the Abbe coefficient of the second lens 120 is V2, the Abbe coefficient of the third lens 130 is V3, the Abbe coefficient of the fourth lens 140 is V4, and the Abbe coefficient of the fifth lens 150 is V5; wherein: V1+V2+V5≧130;

[0086] V2+V3+V4+V5≦220; V1+V3+V5≦200; |V2-V5|≦40; |V3-V5|≧6.

[0087] Specifically, the Abbe coefficient is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe coefficient; conversely, the less the dispersion of the medium, the larger the Abbe coefficient. By reasonably setting the Abbe coefficients of each lens to satisfy the above correspondence, the chromatic aberration and imaging quality of the telephoto lens can be seen.

[0088] Based on the above embodiment, the first lens 110 includes an aspherical plastic lens; the second lens 120 includes an aspherical plastic lens; the third lens 130 includes a spherical glass lens; the fourth lens 140 includes an aspherical plastic lens; and the fifth lens 150 includes an aspherical plastic lens.

[0089] Specifically, the characteristic of an aspheric lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspheric lens has a better curvature radius characteristic and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspheric lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens. On this basis, the aspheric lens can be a plastic aspheric rubber lens, which is conducive to reducing the processing technology of the aspheric lens, and the cost of the aspheric lens is low.

[0090] Furthermore, the spherical lens is characterized by a constant curvature from the center of the lens to the periphery of the lens, ensuring that the lens is set in a simple manner. Furthermore, since the thermal expansion coefficient of a glass lens is small and the stability is good, the spherical lens can be set as a spherical glass lens. The thermal properties of a spherical glass lens are more stable, and when it bears more optical power, it can ensure that the lens has good resolution in a wider temperature range (-40°C to 80°C). In addition, compared with plastic aspherical lenses, the range of glass materials available is wider, and the refractive index and Abbe coefficient are relatively free to choose. To a certain extent, the high-level aberrations and chromatic aberrations of the lens can be controlled to meet the use requirements under complex conditions.

[0091] In the fixed-focus lens provided in the embodiment of the utility model, a spherical glass lens and an aspherical plastic lens can be mixed and matched, so that the cost of the fixed-focus lens can be effectively controlled while ensuring the optical performance of the fixed-focus lens; at the same time, the materials of each lens have a mutual compensation effect, which can ensure that it can still be used normally in high and low temperature environments.

[0092] On the basis of the above embodiment, the fourth lens 140 and the fifth lens 150 are cemented together.

[0093] The bonding of the fourth lens 140 and the fifth lens 150 can be understood as the bonding of the surface of the fourth lens 140 close to the image side with the surface of the fifth lens 150 close to the object side, that is, the image side of the fourth lens 140 and the object side of the fifth lens 150. By bonding the fourth lens 140 and the fifth lens 150, the air gap between the fourth lens 140 and the fifth lens 150 can be reduced, which helps to reduce the total optical length of the lens, and can also reduce the tolerance sensitivity problems such as tilt / eccentricity generated by the lens unit during the assembly process, simplify the assembly procedure during the lens manufacturing process, and improve equipment efficiency. At the same time, the bonding of the fourth lens 140 and the fifth lens 150 can also reduce the light loss caused by reflection between the lenses, improve the illumination, and reduce the risk of ghosting; and the bonding lens can be used to minimize or eliminate chromatic aberration. The use of the bonding lens in the telephoto lens can improve the image quality and reduce the reflection loss of light energy, thereby improving the image quality and enhancing the clarity of the lens imaging. Furthermore, the fourth lens 140 and the fifth lens 150 may be supported by a gasket, or may be bonded by glue, and the utility model does not limit the specific bonding method.

[0094] Based on the above embodiment, the focal length EFL of the telephoto lens satisfies 3mm≤EFL≤4mm; and the total optical length TTL of the telephoto lens satisfies TTL≦14.50, so as to realize an optical system with a long focal length and a short total length.

[0095] Based on the above embodiment, the telephoto lens further includes an aperture 160 and a filter 170; the aperture 160 is disposed in the optical path between the second lens 120 and the third lens 130; and the filter 170 is disposed in the optical path between the fifth lens 150 and the image plane.

[0096] Specifically, by setting the aperture 160, the propagation direction of the light beam can be adjusted, which is beneficial to improving the imaging quality. And the aperture 160 in the telephoto lens can be located in the optical path between the second lens 120 and the third lens 130. The aperture 160 is located in the middle of the telephoto lens to ensure that the front and rear apertures of the telephoto lens are minimized. Furthermore, the filter 170 is set in the optical path between the fifth lens 150 and the image plane. The filter 170 can filter out stray spectra to ensure imaging quality. Furthermore, the telephoto lens can also include flat glass to protect the lens and the image sensor.

[0097] As a feasible implementation method, specific parameters of the telephoto lens are described below.

[0098] Table 1 Optical design values ​​of the telephoto lens in Example 1

[0099] Scope of protection Example 1 Lower limit Upper limit TTL≦14.5 13.6094 13.6094 14.5000 V1+V2+V5≧130.00 167.6847 134.9247 167.6847 |V3-V5|≧6.00 25.6214 6.3801 25.6214 AAG / BFL≧0.35 0.3502 0.3502 1.1845 (T1+T2) / T3≧0.60 1.2044 0.5999 1.2417 (EFL+BFL) / Fno≧3.80 5.4459 3.8000 5.4459 ImgH / BFL≧0.69 0.6999 0.6980 1.0988 ALT / (T2+BFL)≧1.00 1.0405 1.0405 1.6383 (G12+G23+EFL) / (T3+T5)≧1.19 1.4502 1.1901 1.4502 TL / (G23+T3+G34+T4)≧2.40 2.9757 2.3997 3.5946 (T3+G34+T5) / (G12+T2+G23)≧1.00 1.0215 1.0215 1.5362 EFL / (G23+T3+G34)≧1.00 1.6021 1.0000 1.6021 (T1+G23) / (G12+G34)≧0.20 0.4320 0.2289 0.4320 G34 / (T2+T4)≦0.27 0.0203 0.0203 0.2700 V2+V3+V4+V5≦220.00 217.0857 162.8495 217.0857 V1+V3+V5≦200.00 193.3061 173.5122 193.3061 |V2-V5|≦40.00 0.0000 0.0000 32.2074 ALT / (T1+G12)≦3.30 3.2698 2.3802 3.2698 TL / (G23+G34+T4)≧9.00 15.0000 9.0108 15.0000 ALT / (G23+T4)≧9.00 13.4655 9.2366 13.4655 (G34+T4+T5) / T2≦2.20 0.9024 0.9024 2.2000 HFOV / (T3+T4+T5)≦10.00 9.7002 7.6048 9.7002 HFOV / TTL≦3.10 3.1001 2.9096 3.1001 TTL / (T1+T3+G34)≦5.10 4.3842 3.6705 5.0212 (T1+T5) / T2≦2.00 0.9491 0.9491 2.0000 AAG / (T5+G34)≦1.20 1.0915 1.0050 1.1555

[0100] Table 2 Design values ​​of optical physical parameters of a telephoto lens

[0101] Surface number Face type Curvature radius (mm) Thickness(mm) Refractive index / Abbe coefficient (Nd / Vd) Half-oral S1 Aspheric 2.6314 0.6550 1.54 / 55.7 2.5172 S2 Aspheric 1.4145 1.5570 1.8269 S3 Aspheric -3.3451 2.2282 1.54 / 56.0 1.6310 S4 Aspheric -3.0353 -0.0965 2.1881 STO Standard surface Infinity 0.1380 2.0484 S6 Spherical 5.0089 2.3939 1.50 / 81.6 2.6132 S7 Spherical -6.2060 0.0553 2.7172 S8 Aspheric 51.9117 0.4956 1.64 / 23.5 2.5000 S9 Aspheric 2.9110 1.4598 1.54 / 56.0 2.6691 S10 Aspheric -14.3382 2.8030 2.6888 S11 Spherical Infinity 0.6000 H-K9L 3.2524 S12 Spherical Infinity 1.3201 3.3316 IMA Spherical Infinity 0.0000 3.4775

[0102] The surface numbers in Table 2 are numbered according to the order of the surfaces of each lens. "S1" represents the object surface of the first lens, "S2" represents the image surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, where "Infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air, and the refractive index is 1. Among them, S11 represents the filter, and IMA represents the image surface.

[0103] In the present invention, the aspherical lens of the telephoto lens satisfies the following formula:

[0104]

[0105] Among them, z is the distance vector height from the vertex of the aspheric lens when the aspheric lens is at a height of y along the optical axis, c=1 / R, R represents the radius of curvature of the center of the aspheric lens surface, k represents the cone coefficient, and parameters A, B, C, D, E, F, G, H, and I are high-order aspheric coefficients.

[0106] Table 3 Design values ​​of aspheric cone coefficients in a telephoto lens

[0107]

[0108] Among them, "-2.53E-02" means -2.53*10 -2 The remaining coefficients are expressed in this way.

[0109] The light parameters implemented in this embodiment are as follows:

[0110] The focal length f is 3.990mm:

[0111] The aperture number F# is 1.6;

[0112] Total length: 13.6mm;

[0113] The optimal working object distance of this system is infinity.

[0114] Furthermore, Figure 2This is a schematic diagram of the spherical aberration curve of a telephoto lens provided in the first embodiment of the present invention, specifically a schematic diagram of the spherical aberration curve when the pupil radius is 1.2392mm. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm), as shown in FIG. Figure 2 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.2mm, +0.2mm), indicating that the spherical aberration of this fixed-focus lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0115] Figure 3 Schematic diagram of field curvature distortion of a telephoto lens provided by the first embodiment of the present invention. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of field curvature, in units of mm; the vertical coordinate represents the normalized image height, in units of mm. Figure 3 It can be seen that the maximum field of view of the lens provided in this embodiment is 57.716mm, and the field curvature of light at different wavelengths (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm) is effectively controlled, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in %, and the vertical coordinate represents the normalized image height, without units. From Figure 3 It can be seen that the maximum field of view of the lens provided in this embodiment is 57.716 mm, the maximum distortion is 45.6257%, and the maximum distortion is controlled within 50%, ensuring that the imaging distortion is small.

[0116] Figure 4 This is a schematic diagram of chromatic aberration of a telephoto lens provided in Example 1 of the present invention. The vertical direction represents the image height, in mm; the horizontal direction represents the offset of different wavelengths from the optical axis at the image plane after passing through the system, in micrometers (μm). The different linear curves in the figure represent different wavelengths of imaging by the system (0.436μm, 0.486μm, 0.546μm, 0.588μm and 0.656μm); the curves in the vertical directions on both sides of the figure are Airy disks. Figure 4 It can be seen that the chromatic aberration of different wavelengths is controlled within 10μm, indicating that the chromatic aberration of the telephoto lens is well controlled and can meet the application requirements of clear imaging in the visible light range.

[0117] In summary, the telephoto lens provided in the first embodiment of the present invention ensures that the maximum aperture of the lens is 1.6 and the total optical length is 13.6 mm by reasonably setting the number of lenses, the focal power, surface shape, focal length, back focus, total optical length, aperture number, radius of curvature, refractive index and Abbe coefficient of different lenses, and can match a maximum of 1 / 2.7″ sensor chip, and its comprehensive performance meets the requirements of the sensor used.

[0118] Embodiment 2

[0119] Figure 5 Schematic diagram of the structure of a telephoto lens provided in the second embodiment of the present utility model. Figure 5 As shown, the telephoto lens provided in the second embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150 which are arranged in sequence from the object plane to the image plane along the optical axis, wherein the first lens 110 is a positive power lens, the second lens 120 is a positive power lens, the third lens 130 is a positive power lens, the fourth lens 140 is a negative power lens, and the fifth lens 150 is a positive power lens.

[0120] The configuration of the above-mentioned lens is the same as that in the first embodiment, and will not be described in detail here.

[0121] As another feasible implementation, specific parameters of the telephoto lens are described below.

[0122] Table 4 Optical design values ​​of the telephoto lens in Example 2

[0123] Scope of protection Example 2 Lower limit Upper limit TTL≦14.5 14.1410 13.6094 14.5000 V1+V2+V5≧130.00 134.9247 134.9247 167.6847 |V3-V5|≧6.00 6.3801 6.3801 25.6214 AAG / BFL≧0.35 0.5394 0.3502 1.1845 (T1+T2) / T3≧0.60 0.5999 0.5999 1.2417 (EFL+BFL) / Fno≧3.80 5.0954 3.8000 5.4459 ImgH / BFL≧0.69 0.6980 0.6980 1.0988 ALT / (T2+BFL)≧1.00 1.1501 1.0405 1.6383 (G12+G23+EFL) / (T3+T5)≧1.19 1.1901 1.1901 1.4502 TL / (G23+T3+G34+T4)≧2.40 2.3997 2.3997 3.5946 (T3+G34+T5) / (G12+T2+G23)≧1.00 1.5362 1.0215 1.5362 EFL / (G23+T3+G34)≧1.00 1.0000 1.0000 1.6021 (T1+G23) / (G12+G34)≧0.20 0.2289 0.2289 0.4320 G34 / (T2+T4)≦0.27 0.2700 0.0203 0.2700 V2+V3+V4+V5≦220.00 162.8495 162.8495 217.0857 V1+V3+V5≦200.00 173.5122 173.5122 193.3061 |V2-V5|≦40.00 32.2074 0.0000 32.2074 ALT / (T1+G12)≦3.30 2.7255 2.3802 3.2698 TL / (G23+G34+T4)≧9.00 9.0837 9.0108 15.0000 ALT / (G23+T4)≧9.00 12.0619 9.2366 13.4655 (G34+T4+T5) / T2≦2.20 2.2000 0.9024 2.2000 HFOV / (T3+T4+T5)≦10.00 8.2297 7.6048 9.7002 HFOV / TTL≦3.10 2.9835 2.9096 3.1001 TTL / (T1+T3+G34)≦5.10 3.6705 3.6705 5.0212 (T1+T5) / T2≦2.00 1.8204 0.9491 2.0000 AAG / (T5+G34)≦1.20 1.1555 1.0050 1.1555

[0124] Table 5 Design values ​​of optical physical parameters of a telephoto lens

[0125] Surface number Face type Curvature radius (mm) Thickness(mm) Refractive index / Abbe coefficient (Nd / Vd) Half-oral S1 Aspheric 4.6735 0.4999 1.54 / 55.7 2.5514 S2 Aspheric 1.5678 2.0162 1.7597 S3 Aspheric -3.4530 1.2311 1.64 / 23.5 1.6890 S4 Aspheric -3.3220 0.4998 1.9436 STO Standard surface unlimited -0.4311 1.9992 S6 Spherical 4.6794 2.8853 1.50 / 62.1 2.1657 S7 Spherical -4.5255 0.4674 2.4693 S8 Aspheric -29.8853 0.4999 1.65 / 21.5 2.4566 S9 Aspheric 3.1642 1.7413 1.54 / 55.7 2.6206 S10 Aspheric -4.8699 2.8030 2.6858 S11 Spherical Infinity 0.6000 H-K9L 3.2929 S12 Spherical Infinity 1.3283 3.3679 IMA Spherical Infinity 0.0000 3.4721

[0126] The surface numbers in Table 5 are numbered according to the order of the surfaces of each lens. "S1" represents the object surface of the first lens, "S2" represents the image surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, where "Infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air, and the refractive index is 1. Among them, S11 represents a filter, and IMA represents an image surface.

[0127] In the present invention, the aspherical lens of the telephoto lens satisfies the following formula:

[0128]

[0129] Among them, z is the distance vector height from the vertex of the aspheric lens when the aspheric lens is at a height of y along the optical axis, c=1 / R, R represents the radius of curvature of the center of the aspheric lens surface, k represents the cone coefficient, and parameters A, B, C, D, E, F, G, H, and I are high-order aspheric coefficients.

[0130] Table 6 Design values ​​of aspheric cone coefficients in a telephoto lens

[0131]

[0132] Among them, "-1.93E-02" means -1.93*10 -2 The remaining coefficients are expressed in this way.

[0133] The light parameters implemented in this embodiment are as follows:

[0134] The focal length f is 3.421mm:

[0135] The aperture number F# is 1.6;

[0136] Total length: 14.1mm;

[0137] The optimal working object distance of this system is infinity.

[0138] Furthermore, Figure 6 This is a schematic diagram of the spherical aberration curve of a telephoto lens provided in the second embodiment of the present invention, specifically a schematic diagram of the spherical aberration curve when the pupil radius is 1.0625mm. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm), as shown in Figure 1. Figure 6 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.2mm, +0.2mm), indicating that the spherical aberration of this fixed-focus lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0139] Figure 7 Schematic diagram of field curvature distortion of a telephoto lens provided by the second embodiment of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, in units of mm. Figure 7It can be seen that the maximum field of view of the lens provided in this embodiment is 57.716mm, and the field curvature of light at different wavelengths (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm) is effectively controlled, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in %, and the vertical coordinate represents the normalized image height, without units. From Figure 7 It can be seen that the maximum field of view of the lens provided in this embodiment is 57.716 mm, the maximum distortion is 36.3643%, and the maximum distortion is controlled within 40%, ensuring that the imaging distortion is small.

[0140] Figure 8 This is a schematic diagram of chromatic aberration of a telephoto lens provided in Example 2 of the present invention. The vertical direction represents the image height, in mm; the horizontal direction represents the offset of different wavelengths from the optical axis at the image plane after passing through the system, in micrometers (μm). The different linear curves in the figure represent different wavelengths of imaging by the system (0.436μm, 0.486μm, 0.546μm, 0.588μm and 0.656μm); the curves in the vertical directions on both sides of the figure are Airy disks. Figure 8 It can be seen that the chromatic aberration of different wavelengths is controlled within 10μm, indicating that the chromatic aberration of the telephoto lens is well controlled and can meet the application requirements of clear imaging in the visible light range.

[0141] In summary, the telephoto lens provided in the second embodiment of the present invention ensures that the maximum aperture of the lens is 1.6 and the total optical length is 14.1 mm by reasonably setting the number of lenses, the focal power, surface shape, focal length, back focus, total optical length, aperture number, radius of curvature, refractive index and Abbe coefficient of different lenses, and can match a maximum of 1 / 2.7″ sensor chip, and its comprehensive performance meets the requirements of the sensor used.

[0142] Embodiment 3

[0143] Fig. 9 Schematic diagram of the structure of a telephoto lens provided by the third embodiment of the present utility model. Fig. 9 As shown, the telephoto lens provided in the third embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150 which are arranged in sequence from the object plane to the image plane along the optical axis; wherein the first lens 110 is a positive power lens, the second lens 120 is a positive power lens, the third lens 130 is a positive power lens, the fourth lens 140 is a negative power lens, and the fifth lens 150 is a positive power lens.

[0144] The configuration of the above-mentioned lens is the same as that in the first embodiment, and will not be described in detail here.

[0145] As another feasible implementation, specific parameters of the telephoto lens are described below.

[0146] Table 7 Optical design values ​​of the telephoto lens in Example 3

[0147]

[0148]

[0149] Table 8 Design values ​​of optical physical parameters of a telephoto lens

[0150] Surface number Face type Curvature radius (mm) Thickness(mm) Refractive index / Abbe coefficient (Nd / Vd) Half-oral S1 Aspheric 2.0608 0.5491 1.54 / 55.7 3.0420 S2 Aspheric 1.1172 2.7844 2.0224 S3 Aspheric -3.2808 1.8374 1.54 / 56.0 1.5256 S4 Aspheric -2.5859 0.2415 1.9608 STO Standard surface Infinity 0.1176 1.8209 S6 Spherical 4.0294 1.9220 1.47 / 66.7 2.3292 S7 Spherical -6.6453 0.4166 2.3763 S8 Aspheric -31.3189 0.5000 1.64 / 23.5 2.5000 S9 Aspheric 2.3128 3.1258 1.54 / 56.0 2.4154 S10 Aspheric -5.5097 1.0000 2.6689 S11 Spherical Infinity 0.6000 H-K9L 3.0523 S12 Spherical Infinity 1.4056 3.1850 IMA Spherical Infinity 0.0000 3.5315

[0151] The surface numbers in Table 8 are numbered according to the order of the surfaces of each lens. "S1" represents the object surface of the first lens, "S2" represents the image surface of the first lens, and so on. "STO" represents the aperture of the lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, where "Infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air, and the refractive index is 1. Among them, S11 represents a filter, and IMA represents an image surface.

[0152] In the present invention, the aspherical lens of the telephoto lens satisfies the following formula:

[0153]

[0154] Among them, z is the distance vector height from the vertex of the aspheric lens when the aspheric lens is at a height of y along the optical axis, c=1 / R, R represents the radius of curvature of the center of the aspheric lens surface, k represents the cone coefficient, and parameters A, B, C, D, E, F, G, H, and I are high-order aspheric coefficients.

[0155] Table 9 Design values ​​of aspheric cone coefficients in a telephoto lens

[0156]

[0157] Among them, "-2.44E-02" means -2.44*10 -2 The remaining coefficients are expressed in this way.

[0158] The light parameters implemented in this embodiment are as follows:

[0159] The focal length f is 3.074mm:

[0160] The aperture number F# is 1.6;

[0161] Total length: 14.5mm;

[0162] The optimal working object distance of this system is infinity.

[0163] Furthermore, Fig.10 This is a schematic diagram of the spherical aberration curve of a telephoto lens provided in the third embodiment of the present invention, specifically a schematic diagram of the spherical aberration curve when the pupil radius is 0.9548mm. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm), as shown in Figure 1. Fig.10 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.2mm, +0.2mm), indicating that the spherical aberration of this fixed-focus lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0164] Fig.11 This is a schematic diagram of field curvature distortion of a telephoto lens provided by the third embodiment of the present invention. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, in units of mm. Fig.11 It can be seen that the maximum field of view of the lens provided in this embodiment is 57.716mm, and the field curvature of light at different wavelengths (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm) is effectively controlled, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in %, and the vertical coordinate represents the normalized image height, without units. From Figure 7 It can be seen that the maximum field of view of the lens provided in this embodiment is 57.716 mm, the maximum distortion is 28.0039%, and the maximum distortion is controlled within 30%, ensuring that the imaging distortion is small.

[0165] Fig.12 This is a schematic diagram of chromatic aberration of a telephoto lens provided in Example 3 of the present invention. The vertical direction represents the image height, in mm; the horizontal direction represents the offset of different wavelengths from the optical axis at the image plane after passing through the system, in micrometers (μm). The different linear curves in the figure represent different wavelengths of imaging by the system (0.436μm, 0.486μm, 0.546μm, 0.588μm and 0.656μm); the curves in the vertical directions on both sides of the figure are Airy disks. Fig.12It can be seen that the chromatic aberration of different wavelengths is controlled within 10μm, indicating that the chromatic aberration of the telephoto lens is well controlled and can meet the application requirements of clear imaging in the visible light range.

[0166] In summary, the telephoto lens provided in the third embodiment of the present invention ensures that the maximum aperture of the lens is 1.6 and the total optical length is 14.5 mm by reasonably setting the number of lenses, the focal power, surface shape, focal length, back focus, total optical length, aperture number, radius of curvature, refractive index and Abbe coefficient of different lenses, and can match a maximum of 1 / 2.7″ sensor chip, and its comprehensive performance meets the requirements of the sensor used.

[0167] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A telephoto lens, characterized in that: It includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are arranged in sequence from the object plane to the image plane along the optical axis; The first lens is a positive power lens, the second lens is a positive power lens, the third lens is a positive power lens, the fourth lens is a negative power lens, and the fifth lens is a positive power lens.

2. The telephoto lens according to claim 1, characterized in that: The center thickness of the first lens is T1, the center thickness of the second lens is T2, the center thickness of the third lens is T3, the center thickness of the fourth lens is T4, the center thickness of the fifth lens is T5, and the sum of the center thicknesses of the first lens, the second lens, the third lens, the fourth lens and the fifth lens is ALT; The air gap between the center of the first lens and the center of the second lens is G12, the air gap between the center of the second lens and the center of the third lens is G23, the air gap between the center of the third lens and the center of the fourth lens is G34, and the sum of the air gap between the center of the first lens and the center of the second lens, the air gap between the center of the second lens and the center of the third lens, and the air gap between the center of the third lens and the center of the fourth lens is AAG; Among them, (T1+T2) / T3≧0.60; (T3+G34+T5) / (G12+T2+G23)≧1.00; (T1+G23) / (G12+G34)≧0.20; G34 / (T2+T4)≦0.27; ALT / (T1+G12)≦3.30; ALT / (G23+T4)≧9.00; (G34+T4+T5) / T2≦2.20; (T1+T5) / T2≦2.00; AAG / (T5+G34)≦1.

20.

3. The telephoto lens according to claim 2, characterized in that: The total optical length of the telephoto lens is TTL, the back focus of the telephoto lens is BFL, the focal length of the telephoto lens is EFL, and the aperture number of the telephoto lens is Fno; Where: TTL / (G23+T3+G34+T4)≧2.40; TTL / (G23+G34+T4)≧9.00; TTL / (T1+T3+G34)≦5.10; AAG / BFL≧0.35; ALT / (T2+BFL)≧1.00; (EFL+BFL) / Fno≧3.80; (G12+G23+EFL) / (T3+T5)≧1.19; EFL / (G23+T3+G34)≧1.

00.

4. The telephoto lens according to claim 2, characterized in that: The half image height of the telephoto lens is ImgH, the back focus of the telephoto lens is BFL, the field of view angle corresponding to the half image height of the telephoto lens is HFOV, and the total optical length of the telephoto lens is TTL; Among them, ImgH / BFL≧0.69; HFOV / (T3+T4+T5)≦10.00; HFOV / TTL≦3.

10.

5. The telephoto lens according to claim 1, characterized in that: The Abbe coefficient of the first lens is V1, the Abbe coefficient of the second lens is V2, the Abbe coefficient of the third lens is V3, the Abbe coefficient of the fourth lens is V4, and the Abbe coefficient of the fifth lens is V5; Among them: V1+V2+V5≧130; V2+V3+V4+V5≦220; V1+V3+V5≦200; |V2-V5|≦40; |V3-V5|≧6.

6. The telephoto lens according to claim 1, wherein: The first lens includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, and the second lens includes a second object-side surface close to the object plane and a second image-side surface close to the image plane; The first object-side surface is a convex surface, the first image-side surface is a concave surface, and the first lens is a meniscus lens; The second object-side surface is a concave surface, the second image-side surface is a convex surface, and the second lens is a meniscus lens.

7. The telephoto lens according to claim 1, wherein: The first lens comprises an aspherical plastic lens; The second lens comprises an aspherical plastic lens; The third lens comprises a spherical glass lens; The fourth lens comprises an aspherical plastic lens; The fifth lens includes an aspherical plastic lens.

8. The telephoto lens according to claim 1, wherein: The fourth lens and the fifth lens are cemented together.

9. The telephoto lens according to claim 1, wherein: The focal length EFL of the telephoto lens satisfies 3mm≤EFL≤4mm; The total optical length TTL of the telephoto lens satisfies TTL≦14.

50.

10. The telephoto lens according to claim 1, wherein: The telephoto lens also includes an aperture and a filter; The aperture is arranged in the optical path between the second lens and the third lens; The filter is arranged in the optical path between the fifth lens and the image plane.

Images