A large-aperture wide-spectrum imaging lens and electronic device

Abstract

This invention discloses a large-aperture, wide-spectrum imaging lens and electronic device. The lens comprises, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens is a spherical lens with positive refractive index, its object side being convex and its image side being either flat or convex. The second lens is also a spherical lens with positive refractive index, its object side being convex and its image side being convex. The third lens is a spherical lens with negative refractive index, its object side being concave and its image side being concave. The fourth lens is also a spherical lens with negative refractive index, its object side being concave and its image side being concave, and so on. The lens design of this invention employs seven ground spherical glass elements and multiple cemented lens groups to construct a simple optical path structure, which not only facilitates assembly but also significantly improves the assembly yield of optical components.

Description

Technical Field

[0001] This invention relates to the field of large aperture wide-spectrum imaging lens technology, and more particularly to a large aperture wide-spectrum imaging lens and electronic device. Background Technology

[0002] A low-light lens is a lens used for imaging in low-light conditions. It is commonly used in night vision devices, surveillance cameras, and other optical systems that require imaging in dimly lit environments. Existing low-light lenses have at least one of the following drawbacks:

[0003] 1) Generally, lenses have low light transmission and low energy utilization, which cannot meet the requirements for distinguishing objects in low-light environments.

[0004] 2) Generally, lenses have a small spectral range and are used in a limited range of environments, which cannot meet the needs of all-weather use.

[0005] 3) Generally, large-aperture lenses use more elements, resulting in low optical assembly yield, large size, and heavy weight.

[0006] 4) Lenses are prone to focus loss at high and low temperatures, and cannot meet the needs of customers who require clear imaging even with a wide range of ambient temperatures. Summary of the Invention

[0007] In view of this, the object of the present invention is to provide a large-aperture, wide-spectrum imaging lens and electronic device. This lens can at least solve one of the technical shortcomings mentioned in the background art.

[0008] According to one aspect of the present invention, a large-aperture wide-spectrum imaging lens is provided, comprising, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens;

[0009] The first lens is a spherical lens with positive refractive index, and the object side of the first lens is convex and the image side is either flat or convex.

[0010] The second lens is a spherical lens with positive refractive index, and the object side and the image side of the second lens are convex.

[0011] The third lens is a spherical lens with negative refractive index, and the object side and image side of the third lens are concave.

[0012] The fourth lens is a spherical lens with negative refractive index, and the object side and image side of the fourth lens are concave.

[0013] The fifth lens is a spherical lens with positive refractive index, and the object side and the image side of the fifth lens are convex.

[0014] The sixth lens is a spherical lens with positive refractive index, and the object side and the image side of the sixth lens are convex.

[0015] The seventh lens is a spherical lens with negative refractive index, and the object side and image side of the seventh lens are concave.

[0016] The second lens and the third lens are cemented together to form a first cemented lens group; the fourth lens and the fifth lens are cemented together to form a second cemented lens group; and the sixth lens and the seventh lens are cemented together to form a third cemented lens group.

[0017] In the aforementioned technical solution, the lens design employs seven ground spherical glass elements and multiple cemented lens groups to construct a simple optical path structure. This not only facilitates assembly but also significantly improves the assembly yield of optical components. Specifically, the lens of this invention consists of seven ground spherical lenses, which can be described as seven elements in four groups. This innovative structural design utilizes three cemented lens groups, which not only optimizes the lens's optical performance, reduces optical distortion, and improves image quality but also increases mechanical strength, reduces optical assembly difficulty, and simplifies the manufacturing process. Furthermore, by rationally controlling the positive and negative combinations of the optical power of each lens, the lower-order aberrations of the lens are balanced, while reducing sensitivity to tolerances. This maintains the lens's miniaturization while ensuring image quality. Moreover, the optical lens of this invention achieves a light transmission of F1.2, exhibiting excellent image quality with no obvious purple fringing or chromatic aberration, clear and bright image quality, and excellent low-light handling and shallow depth of field due to its large aperture, making it adaptable to more shooting environments. The lens itself has a compact structure, making it more portable than lenses on the market. The lens in this solution is suitable for wavelengths of 435-940nm, meeting the application requirements of special scenarios and ensuring clear imaging in all weather conditions.

[0018] In some embodiments, the first lens is made of a high refractive index material.

[0019] In the aforementioned technical solution, the first lens is designed to have positive optical power, and its shape can be planar convex, biconvex, or crescent-convex to adapt to different optical requirements. Regarding material selection, a material with a high refractive index is chosen. This choice not only ensures a large aperture ratio for the optical system but also helps to reduce the front aperture of the optical system. This design strategy is crucial for achieving lens miniaturization and also facilitates the realization of distortion-free lenses.

[0020] In some embodiments, the lens satisfies the following condition:

[0021] Nd2<1.6; Vd2>70; dn / dT2<-8.5*10E-6; Nd3>1.8; Vd3<30

[0022] In the formula, Nd2 is the refractive index of the second lens; Vd2 is the Abbe coefficient of the second lens; dn / dT2 is the temperature coefficient of refractive index of the material of the second lens; Nd3 is the refractive index of the third lens; and Vd3 is the Abbe coefficient of the third lens.

[0023] In the aforementioned technical solution, the second lens is made of a material with a negative refractive index. This material choice effectively mitigates temperature-induced refractive index changes, optimizing thermal stability and ensuring consistent imaging performance across different ambient temperatures. Furthermore, the first cemented lens group utilizes a combination of high- and low-dispersion materials, which not only facilitates the correction of second-order chromatic aberration but also significantly reduces chromatic aberration and astigmatism during imaging, thereby significantly improving the lens's image quality.

[0024] In some embodiments, the second lens and the third lens are cemented together to form a first cemented lens group, satisfying the following condition:

[0025] Vd2- Vd3>40

[0026] In the formula, Vd2 is the Abbe coefficient of the second lens; Vd3 is the Abbe coefficient of the third lens.

[0027] In the aforementioned technical solution, in order to further ensure the correction effect and maximize the imaging quality, the Abbe number of the second and third lenses is limited as described above.

[0028] In some embodiments, the lens satisfies the following condition:

[0029] Nd4>1.7; Vd4<30; Nd5>1.95; Vd5<26

[0030] In the formula, Nd4 is the refractive index of the fourth lens; Vd4 is the Abbe coefficient of the fourth lens; Nd5 is the refractive index of the fifth lens; and Vd5 is the Abbe coefficient of the fifth lens.

[0031] In the aforementioned technical solution, the design strategy for the second cemented lens group involves using materials with high refractive index and high dispersion for both lenses. This approach helps control the refraction angle of light on the lenses, thereby optimizing the light propagation path. This combination effectively reduces chromatic aberration at magnification and on-axis. Specifically, this material selection significantly reduces chromatic aberration at magnification and on-axis because high-dispersion materials have different refractive indices at different wavelengths, resulting in more precise focusing of light and thus reducing the impact of chromatic aberration. Furthermore, the use of high-refractive index materials helps improve the optical aperture ratio of the lens, enabling lens miniaturization and improved image quality.

[0032] In some embodiments, the fourth lens and the fifth lens are cemented together to form a second cemented lens group, satisfying the following condition:

[0033] Nd5-Nd4>0.25; 0.8 <Vd5 / Vd4<1

[0034] In the formula, Nd4 is the refractive index of the fourth lens; Vd4 is the Abbe coefficient of the fourth lens; Nd5 is the refractive index of the fifth lens; and Vd5 is the Abbe coefficient of the fifth lens.

[0035] In the aforementioned technical solution, in order to further ensure the control effect and maximize the imaging quality, the refractive index and Abbe number of the fourth and fifth lenses are limited as described above.

[0036] In some embodiments, the lens satisfies the following condition:

[0037] Nd6>1.7; Vd6<20; Nd7>1.8; Vd7<25

[0038] In the formula, Nd6 is the refractive index of the sixth lens; Vd6 is the Abbe coefficient of the sixth lens; Nd7 is the refractive index of the seventh lens; and Vd7 is the Abbe coefficient of the seventh lens.

[0039] In the aforementioned technical solution, the design strategy of the third cemented lens group involves using both lenses made of high-refractive-index, high-dispersion materials. This approach helps control the refraction angle of light on the lenses, thereby optimizing the light propagation path. This combination effectively reduces on-axis chromatic aberration in the lens. Specifically, because high-dispersion materials have different refractive indices at different wavelengths, the focusing position of light is more precise, thus reducing the impact of chromatic aberration. Furthermore, the use of high-refractive-index materials helps to reduce the rear aperture radius of the lens, which not only contributes to lens miniaturization but also improves the compactness of the optical system.

[0040] In some embodiments, the sixth lens and the seventh lens are cemented together to form a third cemented lens group, satisfying the following condition:

[0041] 0.72 <Vd6 / Vd7<1

[0042] In the formula, Vd6 is the Abbe coefficient of the sixth lens; Vd7 is the Abbe coefficient of the seventh lens.

[0043] In the aforementioned technical solution, in order to further ensure the control effect and maximize the imaging quality, the refractive index and Abbe number of the sixth and seventh lenses are limited as described above.

[0044] In some embodiments, the first lens, the second lens, and the third lens form a first lens group; the fourth lens, the fifth lens, the sixth lens, and the seventh lens form a second lens group;

[0045] The lens satisfies the following conditional expressions:

[0046] 3 < fs1 / f < 8; 0.4 < fs2 / f < 0.8

[0047] 0.2 < H / TTL < 0.3; 0.2 < BFL / TTL < 0.3

[0048] Wherein, fs1 is the focal length of the first lens group; fs2 is the focal length of the second lens group; f is the focal length of the lens; H is the image height; TTL is the total optical length of the lens; BFL is the back focal length of the lens.

[0049] In the above technical solution, the ratio of the combined focal length fs1 of the first lens group arranged along the object side to the effective focal length of the lens satisfies 3 < fs1 / f < 8. Through this design, light can pass through the aperture ST at a gentle angle, thereby reducing the tolerance sensitivity and improving the stability of the optical system in the front and back directions. In addition, this solution helps to miniaturize the entire optical lens. The ratio of the combined focal length fs2 of the second lens group arranged along the object side to the effective focal length of the optical lens satisfies 0.4 < fs1 / f < 0.8. This design enables the second lens group to effectively bear the optical power distribution of the optical lens, which is not only beneficial to the aberration balance between the first lens group and the second lens group, thus facilitating the reduction of the length of the optical lens and further realizing the miniaturization of the entire optical lens. In addition, two parameter ratios are also proposed, namely 0.2 < H / TTL < 0.3, 0.2 < BFL / TTL < 0.3. The optimization of these parameters is beneficial to improving the imaging quality while the optical lens takes into account miniaturization. At the same time, the ratio of BFL / TTL plays an important role in both enhancing the relative illumination of the system and the miniaturization design.

[0050] According to another aspect of the present invention, there is provided an electronic device including the above-mentioned large-aperture wide-spectrum imaging lens; and

[0051] An image sensor configured to receive the image formed by the large-aperture wide-spectrum imaging lens.

[0052] In the above technical solution, the advantages of this electronic device rely on the large-aperture wide-spectrum imaging lens, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 , Figure 9 , Figure 17 This is a schematic diagram of the optical system of Example 1 to Example 4 of the present invention, which is a large aperture wide spectrum imaging lens;

[0055] Figure 2 , Figure 10 , Figure 18 These are the MTF diagrams of the optical systems of Examples 1 to 4 of the large aperture wide spectrum imaging lens of the present invention under visible light 435-650nm.

[0056] Figure 3 , Figure 11 , Figure 19 These are the MTF diagrams of the optical systems of Examples 1 to 4 of the large aperture wide spectrum imaging lens of the present invention in the near-infrared 850-940nm range.

[0057] Figure 4 , Figure 12 , Figure 20 These are field curvature and distortion diagrams of the optical systems of Examples 1 to 4 of the present invention for a large aperture wide spectrum imaging lens under visible light 435-650nm.

[0058] Figure 5 , Figure 13 , Figure 21 This is a diagram of longitudinal chromatic aberration (magnification chromatic aberration) in the visible light 435-650nm of the optical system of the large aperture wide spectrum imaging lens of Example 1 to Example 4 of the present invention;

[0059] Figure 6 , Figure 14 , Figure 22 This is an on-axis chromatic aberration diagram of the optical system of the large aperture wide spectrum imaging lens of Examples 1 to 4 of the present invention in the visible light 435-650nm.

[0060] Figure 7 , Figure 15 , Figure 23 This is a dot plot of the visible light 435-650nm of the optical system of the large aperture wide spectrum imaging lens of Example 1 to Example 4 of the present invention;

[0061] Figure 8 , Figure 16 , Figure 24This is a relative illumination diagram of the optical system of Example 1 to Example 4 of the large aperture wide spectrum imaging lens of the present invention under visible light 435-650nm;

[0062] Figure 25 This is a schematic diagram of the structure of an electronic device example 4 of the present invention. Detailed Implementation

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] The purpose of this invention is to provide a large-aperture, wide-spectrum imaging lens and electronic device with high optical performance. Embodiments according to the invention will now be described in detail with reference to the accompanying drawings.

[0065] Figure 1 , Figure 9 , Figure 17 These are cross-sectional views of large-aperture broadband imaging lenses (optical systems) according to Examples 1 to 3. The large-aperture broadband imaging lenses according to each example are used in imaging devices including digital video cameras, digital still cameras, broadcast cameras, surveillance cameras, etc., and in interchangeable-lens optical devices. In each cross-sectional view, the left side is the object-side OBJ and the right side is the image-side IMA. In each cross-sectional view, Li represents the i-th lens, and Ci represents the i-th cemented lens group. ST represents the aperture stop (fixed aperture stop or visible aperture stop), and OA represents the optical axis. IMA represents the image plane, and when the large-aperture broadband imaging lenses 1 to 3 according to each example are used in the imaging optical system of a digital video camera or digital still camera, a solid-state imaging element (photoelectric conversion element), such as a CMOS image sensor or a CCD image sensor, is arranged on the image plane IMA.

[0066] According to the examples, the large aperture wide-spectrum imaging lenses include, in order from the object side to the image side, the first lens L1, the second lens L2, the third lens L3, the aperture ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the filter G1, and the protective sheet G2.

[0067] The first lens L1 is a spherical lens with positive refractive index. The object side of the first lens is convex, and the image side is either flat or convex.

[0068] The second lens L2 is a spherical lens with positive refractive index, and the object side and the image side of the second lens are convex.

[0069] The third lens L3 is a spherical lens with negative refractive index, and the object side and image side of the third lens are concave.

[0070] The fourth lens L4 is a spherical lens with negative refractive index, and the object side and image side of the fourth lens are concave.

[0071] The fifth lens L5 is a spherical lens with positive refractive index, and the object side and the image side of the fifth lens are convex.

[0072] The sixth lens L6 is a spherical lens with positive refractive index, and the object side and image side of the sixth lens are convex.

[0073] The seventh lens L7 is a spherical lens with negative refractive index, and the object side and image side of the seventh lens are concave.

[0074] Wherein, the second lens L2 and the third lens L3 are cemented together to form a first cemented lens group C1; the fourth lens L4 and the fifth lens L5 are cemented together to form a second cemented lens group C2; and the sixth lens L6 and the seventh lens L7 are cemented together to form a third cemented lens group C3.

[0075] This lens design employs seven ground spherical glass elements and multiple cemented lens groups to create a simple optical path structure. This not only facilitates assembly but also significantly improves the assembly yield of optical components. Specifically, the lens of this invention consists of seven ground spherical lenses, which can be described as seven elements in four groups. This innovative structural design utilizes three cemented lens groups, which not only optimizes the lens's optical performance, reduces optical distortion, and improves image quality, but also increases mechanical strength, reduces optical assembly difficulty, and simplifies the manufacturing process. Furthermore, by rationally controlling the positive and negative combinations of the optical power of each lens, the lower-order aberrations of the lens are balanced, while reducing sensitivity to tolerances. This maintains the lens's miniaturization while ensuring image quality. Moreover, the optical lens of this invention achieves a light transmission of F1.2, exhibits excellent image quality with no obvious purple fringing or chromatic aberration, and provides clear and bright image quality. The large aperture also provides excellent low-light handling and a shallow depth of field, making it suitable for a wider range of shooting environments. Furthermore, the lens itself has a compact structure, making it more portable than lenses on the market. The lens in this solution is suitable for wavelengths of 435-940nm, meeting the application requirements of special scenarios and ensuring clear imaging in all weather conditions.

[0076] In this embodiment, the first lens L1 is made of a high-refractive-index material. The first lens is designed to have positive optical power, and its shape can be planar convex, biconvex, or crescent-convex to adapt to different optical requirements. The selection of a high-refractive-index material not only ensures a large aperture ratio for the optical system but also helps to reduce the front aperture of the optical system. This design strategy is crucial for achieving lens miniaturization and also facilitates the realization of distortion-free lenses.

[0077] The large-aperture broadband imaging lens in each example can satisfy at least one of the following setting conditions 1) to 7):

[0078] 1)Nd2<1.6; Vd2>70; dn / dT2<-8.5*10E-6; Nd3>1.8; Vd3<30;

[0079] 2) Vd2 - Vd3 > 40;

[0080] 3)Nd4>1.7; Vd4<30; Nd5>1.95; Vd5<26;

[0081] 4) Nd5-Nd4>0.25; 0.8 <Vd5 / Vd4<1;

[0082] 5)Nd6>1.7; Vd6<20; Nd7>1.8; Vd7<25;

[0083] 6)0.72 <Vd6 / Vd7<1;

[0084] 7)3 <fs1 / f<8;0.4<fs2 / f<0.8;0.2<H / TTL<0.3;0.2<BFL / TTL<0.3

[0085] In the above conditions, Nd2 is the refractive index of the second lens; Vd2 is the Abbe coefficient of the second lens; dn / dT2 is the temperature coefficient of refractive index of the material of the second lens; Nd3 is the refractive index of the third lens; Vd3 is the Abbe coefficient of the third lens; Nd4 is the refractive index of the fourth lens; Vd4 is the Abbe coefficient of the fourth lens; Nd5 is the refractive index of the fifth lens; Vd5 is the Abbe coefficient of the fifth lens; Nd6 is the refractive index of the sixth lens; Vd6 is the Abbe coefficient of the sixth lens; Nd7 is the refractive index of the seventh lens; Vd7 is the Abbe coefficient of the seventh lens; fs1 is the focal length of the first lens group; fs2 is the focal length of the second lens group; f is the focal length of the lens; H is the image height; TTL is the total optical length of the lens; BFL is the optical back focal length of the lens.

[0086] Condition 1) defines the refractive index and Abbe number of the second and third lenses. By appropriately setting the conditions, temperature-induced refractive index changes can be effectively controlled, optimizing thermal stability and ensuring consistent imaging performance of the lens under different ambient temperatures. Furthermore, the first cemented lens group uses a combination of high- and low-dispersion materials, which not only helps correct second-order chromatic aberration but also significantly reduces chromatic aberration and astigmatism during imaging, thus significantly improving the lens's image quality. If the refractive index of the second lens exceeds the upper limit, it will be difficult to compensate for the spherical aberration formed by the first lens. If the Abbe number of the second lens is below the lower limit, it will be detrimental to correcting axial chromatic aberration and magnification chromatic aberration of the lens. If the refractive index of the third lens is below the lower limit, uneven power distribution and reduced tolerances will result in low yield. If the Abbe number of the third lens exceeds the upper limit, it will be detrimental to correcting axial chromatic aberration and magnification chromatic aberration of the lens. Furthermore, to reliably obtain the effect of condition 1), it is more preferable to set the values ​​of condition 1) to Nd2 = 1.57; Vd2 = 71.3; dn / dT2 < -8.5 * 10E-6; Nd3 = 1.81; V d3= 29.83

[0087] Condition 2) further defines the Abbe coefficients of the second and third lenses. By appropriately setting the conditions, the correction effect is further guaranteed, and the image quality is maximized. If the value is lower than the lower limit, the axial chromatic aberration and magnification chromatic aberration of the corrected lens are insufficient. In addition, in order to reliably obtain the effect of condition 2), it is more preferable to set the value of condition 2) to Vd2 - Vd3 = 41.47.

[0088] Condition 3) defines the refractive index and Abbe number of the fourth and fifth lenses. By appropriately setting these conditions, it is beneficial to control the light refraction angle on the lenses to optimize the light propagation path. This combination can effectively reduce chromatic aberration and on-axis chromatic aberration of the lens. Specifically, this material selection helps to significantly reduce chromatic aberration and on-axis chromatic aberration of the lens because high-dispersion materials have different refractive indices at different wavelengths, making the focusing position of light more precise, thereby reducing the impact of chromatic aberration. In addition, the use of high-refractive-index materials helps to improve the optical aperture ratio of the lens, enabling lens miniaturization and improving image quality. If the refractive index of the fourth lens is below the lower limit, a very large curvature change is required to correct chromatic aberration, and a large curvature change is not conducive to the manufacturing of optical lenses. If the Abbe number of the fourth lens is above the upper limit, it is not conducive to correcting axial chromatic aberration and chromatic aberration of the lens. If the refractive index of the fifth lens is below the lower limit, a very large curvature change is required to bear the optical power, and a large curvature change is not conducive to the manufacturing of optical lenses. If the Abbe number of the fifth lens is higher than the upper limit, it will be detrimental to correcting the axial chromatic aberration and magnification chromatic aberration of the lens. In addition, in order to reliably obtain the effect of condition 3), it is more preferable to set the values ​​of condition 3) to Nd4=1.72; Vd4=29.5; Nd5=2.00; Vd5=25.46.

[0089] Condition 4) further defines the ratio between the refractive index and Abbe coefficient of the fourth and fifth lenses. By appropriately setting the conditions, the control effect is further guaranteed, maximizing the image quality. If the refractive index ratio is below the lower limit, it is difficult to compensate for the aberrations formed by the lens in front of the aperture stop. If the Abbe coefficient ratio is above the upper limit, the yield is low due to uneven power distribution and reduced tolerance. Furthermore, to reliably obtain the effect of condition 4), it is more preferable to set the value of condition 4) to Nd5 - Nd4 = 0.28; 0.8. <Vd5 / Vd4<1。

[0090] Condition 5) defines the refractive index and Abbe number of the sixth and seventh lenses. By appropriately setting these conditions, it is beneficial to control the refraction angle of light on the lens, thereby optimizing the light propagation path. This combination can effectively reduce axial chromatic aberration of the lens. Specifically, since high-dispersion materials have different refractive indices at different wavelengths, the focusing position of light is more precise, thus reducing the impact of chromatic aberration. In addition, the use of high-refractive-index materials helps to compress the rear end radius of the lens, which not only helps to achieve lens miniaturization but also improves the compactness of the optical system. If the refractive index of the sixth lens is below the lower limit, the uneven distribution of optical power and the reduction in tolerance will lead to low yield. If the Abbe number of the sixth lens is above the upper limit, it is not conducive to correcting axial chromatic aberration and magnification chromatic aberration of the lens. If the refractive index of the seventh lens is below the lower limit, the center thickness of the lens will increase to ensure the distribution of optical power. This will increase the cost of lens materials and the weight of the lens, which is not conducive to the realization of lightweight and low-cost lenses. If the Abbe number of the seventh lens is above the upper limit, it is not conducive to correcting axial chromatic aberration and magnification chromatic aberration of the lens. Furthermore, in order to reliably obtain the effect of condition 5), it is more preferable to set the value of condition 5) to Nd6=1.72; Vd6=17.9; Nd7=1.85; Vd7=24.8.

[0091] Condition 6) further defines the Abbe coefficient ratio of the sixth and seventh lenses. By appropriately setting the conditions, the control effect is further guaranteed, and the image quality is maximized. If the Abbe coefficient ratio is lower than the lower limit, it is not conducive to correcting the axial chromatic aberration and magnification chromatic aberration of the lens. If the Abbe coefficient ratio is higher than the upper limit, it is not conducive to correcting the axial chromatic aberration and magnification chromatic aberration of the lens. In addition, in order to reliably obtain the effect of condition 6), it is more preferable to set the value of condition 6) to Vd6 / Vd7 = 0.72.

[0092] A detailed description of large-aperture broadband imaging lenses based on various examples will now be provided.

[0093] Example 1

[0094] Please refer to the optical structure of Example 1. Figure 1 The specific parameters of Example 1 are shown in Table 1 below. In Example 1, the optical system has a focal length f = 22.5 mm, a light transmission FNO = 1.2, a field of view FOV = 22.5°, a target surface size IMH = 8.81 mm, an image height H = 8.81 mm, a total optical length TTL = 35 mm, and an optical back focal length BFL = 7.75 mm. The first, second, and third lenses form the first lens group, which has a focal length fs1 = 71.3 mm. The fourth, fifth, sixth, and seventh lenses form the second lens group, which has a focal length fs2 = 14.55 mm.

[0095] Conditions 1) to 7):

[0096] 1)Nd2=1.57; Vd2=71.3; dn / dT2<-8.5*10E-6; Nd3=1.81; Vd3=29.83;

[0097] 2) Vd2 - Vd3 = 41.47;

[0098] 3)Nd4=1.72; Vd4=29.5; Nd5=2; Vd5=25.46;

[0099] 4)Nd5- Nd4=0.28; Vd5 / Vd4=0.863;

[0100] 5)Nd6=1.72; Vd6=17.9; Nd7=1.85; Vd7=24.8;

[0101] 6) Vd6 / Vd7=0.721;

[0102] 7) fs1 / f=3.17; fs2 / f=0.65; H / TTL=0.25; BFL / TTL=0.22;

[0103] Table 1 Parameter Table for Example 1

[0104]

[0105] Please see Figure 2 The MTF chart of the optical system in Example 1 under visible light (435-650nm) shows that at a field of view (FOV) of 22.5° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.3 at 250lp / mm and greater than 0.6 at 125lp / mm. This indicates that this example has high resolution, good imaging quality, and high performance at both the mid-frequency and high-frequency ranges.

[0106] Please see Figure 3 The MTF chart of the optical system in Example 1 in the near-infrared 850-940nm range shows that at a field of view (FOV) of 22.5° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.3 at a frequency of 250lp / mm and greater than 0.55 at a frequency of 125lp / mm. This indicates that this example has high resolution, good imaging quality, and high performance at both the mid-frequency and high-frequency ranges.

[0107] Please see Figure 4 The field curvature and distortion chart of the optical system in Example 1 under visible light 435-650nm shows that the edge field distortion values ​​are all less than ±1%, the optical distortion is small under large field of view, the imaging effect is good, and the imaging reproduction is high.

[0108] Please see Figure 5The longitudinal chromatic aberration (magnification chromatic aberration) diagram of the optical system in Example 1 under visible light 435-650nm shows the magnification chromatic aberration of the lens as the field of view changes. The five lines correspond to wavelengths of 0.435um, 0.51um, 0.55um, 0.61um, and 0.65um, respectively. The horizontal axis represents the magnification chromatic aberration value, and the vertical axis represents the normalized field of view angle. The longitudinal chromatic aberration (magnification chromatic aberration) across the entire field of view is less than 2.5um. In such a large target surface and large light transmission optical system, the magnification chromatic aberration is negligible, so it can be called "zero chromatic aberration".

[0109] Please see Figure 6 Example 1 shows the on-axis chromatic aberration diagram of the optical system in the visible light range of 435-650nm, representing the axial chromatic aberration of the lens as the aperture changes. The five lines correspond to wavelengths of 0.435µm, 0.51µm, 0.55µm, 0.61µm, and 0.65µm, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. It can be seen that the lens has small chromatic aberration, high color reproduction, and a color shift of less than 0.03mm across the entire field of view. It exhibits good color reproduction, small chromatic aberration, and minimal blue-violet fringing.

[0110] Please see Figure 7 The dot plot of the optical system in Example 1 under visible light 435-650nm has an RMS of less than 2.52um across the entire field of view. The more compact the dot plot, the smaller the aberrations.

[0111] Please see Figure 8 The relative illumination diagram of the optical system in Example 1 under visible light 435-650nm shows that the lens maintains a relative illumination greater than 90% while ensuring a target half-image height of 4.405.

[0112] Example 2

[0113] Please refer to the optical structure of Example 2. Figure 9 The specific parameters of Example 2 are shown in Table 2 below. In Example 3, the optical system has a focal length f = 22.5 mm, a light transmission FNO = 1.2, a field of view FOV = 22.2°, a target surface size IMH = 8.81 mm, an image height H = 8.81 mm, a total optical length TTL = 35 mm, and an optical back focal length BFL = 7.75 mm. The first, second, and third lenses form the first lens group, which has a focal length fs1 = 80 mm. The fourth, fifth, sixth, and seventh lenses form the second lens group, which has a focal length fs2 = 14 mm.

[0114] Conditions 1) to 7):

[0115] 1)Nd2=1.57; Vd2=71.3; dn / dT2<-8.5*10E-6; Nd3=1.81; Vd3=29.83;

[0116] 2) Vd2 - Vd3 = 41.47;

[0117] 3)Nd4=1.72; Vd4=29.5; Nd5=2; Vd5=25.46;

[0118] 4)Nd5- Nd4=0.28; Vd5 / Vd4=0.863;

[0119] 5)Nd6=1.72; Vd6=17.9; Nd7=1.85; Vd7=24.8;

[0120] 6) Vd6 / Vd7=0.721;

[0121] 7) fs1 / f=3.56; fs2 / f=0.62; H / TTL=0.25; BFL / TTL=0.22;

[0122] Table 2 Example 2 Parameter Table

[0123]

[0124] Please see Figure 10 The MTF chart of the optical system in Example 2 under visible light (435-650nm) shows that at a field of view (FOV) of 22.2° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.3 at a frequency of 250lp / mm and greater than 0.55 at a frequency of 125lp / mm. This indicates that the example has high resolution and good imaging quality.

[0125] Please see Figure 11 The MTF chart of the optical system in Example 2 at the near-infrared 850-940nm shows that, with a field of view (FOV) of 22.2° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.25 at a frequency of 250 lp / mm and greater than 0.55 at a frequency of 125 lp / mm. This indicates that the example has high resolution and good imaging quality.

[0126] Please see Figure 12 The field curvature and distortion chart of the optical system in Example 2 under visible light 435-650nm shows that the edge field distortion values ​​are all less than ±0.5%, the optical distortion is small under large field of view, the imaging effect is good, and the imaging reproduction is high.

[0127] Please see Figure 13Example 2 shows the longitudinal chromatic aberration curve (magnification chromatic aberration diagram) of the optical system in the visible light range of 435-650nm. This represents the chromatic aberration of the lens as the field of view changes. The five lines correspond to wavelengths of 0.435µm, 0.51µm, 0.55µm, 0.61µm, and 0.65µm, respectively. The horizontal axis represents the chromatic aberration value, and the vertical axis represents the normalized field of view angle. The longitudinal chromatic aberration (magnification chromatic aberration) across the entire field of view is less than 2.5µm. In such a large target surface and high-throughput optical system, the chromatic aberration is negligible, therefore it can be called "zero chromatic aberration".

[0128] Please see Figure 14 Example 2 shows the on-axis chromatic aberration curve of the optical system in the visible light range of 435-650nm, representing the axial chromatic aberration of the lens as the aperture changes. The five lines correspond to wavelengths of 0.435um, 0.51um, 0.55um, 0.61um, and 0.65um, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. It can be seen that the lens has small chromatic aberration, high color reproduction, and a color focus shift of less than 0.035mm across the entire field of view. It has good color reproduction, small chromatic aberration, and no obvious blue-purple fringing.

[0129] Please see Figure 15 In Example 2, the dot plot of the optical system under visible light 435-650nm shows that the RMS is less than 3um across the entire field of view. The more compact the dot plot, the smaller the aberrations.

[0130] Please see Figure 16 The relative illumination of the optical system in Example 2 in the visible light 435-650nm range shows that the lens maintains a relative illumination greater than 90% while ensuring a target half-image height of 4.405.

[0131] Example 3

[0132] Please refer to the optical structure of Example 3. Figure 17 The specific parameters of Example 3 are shown in Table 3 below. In Example 3, the optical system has a focal length f = 22.5 mm, a light transmission FNO = 1.2, a field of view FOV = 22.4°, a target surface size IMH = 8.81 mm, an image height H = 8.81 mm, a total optical length TTL = 35 mm, and an optical back focal length BFL = 8 mm. The first, second, and third lenses form the first lens group, which has a focal length fs1 = 158 mm. The fourth, fifth, sixth, and seventh lenses form the second lens group, which has a focal length fs2 = 13 mm.

[0133] Conditions 1) to 7):

[0134] 1)Nd2=1.57; Vd2=71.3; dn / dT2<-8.5*10E-6; Nd3=1.81; Vd3=29.83;

[0135] 2) Vd2 - Vd3 = 41.47;

[0136] 3)Nd4=1.72; Vd4=29.5; Nd5=2; Vd5=25.46;

[0137] 4)Nd5- Nd4=0.28; Vd5 / Vd4=0.863;

[0138] 5)Nd6=1.72; Vd6=17.9; Nd7=1.85; Vd7=24.8;

[0139] 6) Vd6 / Vd7=0.721;

[0140] 7) fs1 / f=7.02; fs2 / f=0.58; H / TTL=0.25; BFL / TTL=0.23;

[0141] Table 3 Example 3 Parameter Table

[0142]

[0143] Please see Figure 18 The MTF chart of the optical system in Example 3 under visible light (435-650nm) shows that at a field of view (FOV) of 22.4° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.4 at a frequency of 250lp / mm and greater than 0.65 at a frequency of 125lp / mm, indicating that this example has high resolution and good imaging quality.

[0144] Please see Figure 19 The MTF chart of the optical system in Example 3 in the near-infrared 850-940nm range shows that, with a field of view (FOV) of 22.4° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.3 at a frequency of 250 lp / mm and greater than 0.6 at a frequency of 125 lp / mm. This indicates that the example has high resolution and good imaging quality.

[0145] Please see Figure 20 The field curvature and distortion charts of the optical system in Example 3 under visible light 435-650nm show that the edge field distortion values ​​are all less than ±1.5%, the optical distortion is small under large field of view, the imaging effect is good, and the imaging reproduction is high.

[0146] Please see Figure 21The longitudinal chromatic aberration curve (magnification chromatic aberration diagram) of the optical system in Example 3 under visible light 435-650nm represents the magnification chromatic aberration of the lens as the field of view changes. The five lines correspond to wavelengths of 0.435um, 0.51um, 0.55um, 0.61um, and 0.65um, respectively. The horizontal axis represents the magnification chromatic aberration value, and the vertical axis represents the normalized field of view angle. The longitudinal chromatic aberration (magnification chromatic aberration) across the entire field of view is less than 3um. In such a large target surface and large light transmission optical system, the magnification chromatic aberration is negligible, so it can be called "zero chromatic aberration".

[0147] Please see Figure 22 Example 3 shows the on-axis chromatic aberration curve of the optical system in the visible light range of 435-650nm, which represents the axial chromatic aberration of the lens as the aperture changes. The five lines correspond to wavelengths of 0.435um, 0.51um, 0.55um, 0.61um, and 0.65um, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. It can be seen that the lens has small chromatic aberration, high color reproduction, and a chromatic focus shift of less than 0.06mm across the entire field of view.

[0148] Please see Figure 23 The dot plot of the optical system in Example 3 under visible light 435-650nm shows that the RMS is less than 3um across the entire field of view. The more compact the dot plot, the smaller the aberrations.

[0149] Please see Figure 24 The relative illumination of the optical system in Example 3 in the visible light 435-650nm range shows that the lens maintains a relative illumination greater than 90% while ensuring a target half-image height of 4.405.

[0150] Based on Examples 1 to 3, this case has the following advantages:

[0151] 1. The optical lens of the present invention achieves a light transmission of F1.2, with excellent image quality, no obvious purple fringing or chromatic aberration, clear and bright image quality, and excellent low-light processing capability and shallow depth of field brought by the large aperture, which can adapt to more shooting environments. In addition, the lens itself has a compact structure and is more portable than lenses on the market.

[0152] 2. The lens wavelength range of this solution is 435-940 nm; it meets the application requirements of special scenarios and covers the need for clear imaging in all weather conditions.

[0153] 3. The lens in this solution uses 7 pieces of ground spherical glass and mostly cemented lenses, resulting in a simple optical path structure, easy assembly, and high optical assembly yield.

[0154] 4. The lens in this design meets the temperature drift requirement from -40℃ to 85℃, achieving a heat-free design.

[0155] 5. The lens of this invention uses 7 ground spherical lenses, which can be described as 7 elements in 4 groups in terms of lens structure. The innovative design uses 3 groups of cemented lenses, which improves the optical performance of the lens, reduces optical distortion, improves image quality, increases mechanical strength, reduces optical assembly difficulty, and simplifies the manufacturing process.

[0156] Example 4

[0157] For reference Figure 25 A description of an electronic device A according to Example 4 of the present invention will be given. Figure 25 This is a schematic diagram of an electronic device (industrial camera) used in a camera optical system, based on any of the large-aperture wide-spectrum imaging lenses in Examples 1 to 3.

[0158] exist Figure 25 In the figures, reference numeral A2 indicates the main body of the electronic device, and reference numeral A1 indicates any of the camera optical systems (interchangeable lenses) including the large-aperture broadband imaging lenses according to Examples 1 to 3. Reference numeral A3 indicates an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built into the camera body A2 and receives light (the optical image formed by the camera optical system A1) from the camera optical system A1 and performs photoelectric conversion.

[0159] By using a large-aperture broadband imaging lens according to any one of Examples 1 to 3 in an electronic device such as a digital still camera, an electronic device with a large-aperture broadband imaging lens having high optical performance can be obtained.

[0160] Each example can provide electronic devices with high optical performance.

[0161] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims will be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A large-aperture, wide-spectrum imaging lens, characterized in that, From the object side to the image side, the lenses are arranged in the following order: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, and seventh lens. The first lens is a spherical lens with positive refractive index. The object side of the first lens is convex, and the image side is either flat or convex. The focal length is 29.

78. The second lens is a spherical lens with positive refractive index. The object side and the image side of the second lens are convex, and the focal length is 15.

16. The third lens is a spherical lens with negative refractive index. The object side and image side of the third lens are concave, and the focal length is -7.

02. The fourth lens is a spherical lens with negative refractive index. The object side and image side of the fourth lens are concave, and the focal length is -7.

87. The fifth lens is a spherical lens with positive refractive index. The object side and image side of the fifth lens are convex, and the focal length is 6.

77. The sixth lens is a spherical lens with positive refractive index. The object side and image side of the sixth lens are convex, and the focal length is 7.

79. The seventh lens is a spherical lens with negative refractive index. The object side and image side of the seventh lens are concave, and the focal length is -8.

10. The second lens and the third lens are cemented together to form a first cemented lens group; the fourth lens and the fifth lens are cemented together to form a second cemented lens group; and the sixth lens and the seventh lens are cemented together to form a third cemented lens group.

2. The large-aperture broadband imaging lens as described in claim 1, characterized in that, The first lens is made of a high refractive index material.

3. The large-aperture broadband imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: Nd2<1.6; Vd2>70; dn / dT2<-8.5*10E-6; Nd3>1.8; Vd3<30 In the formula, Nd2 is the refractive index of the second lens; Vd2 is the Abbe coefficient of the second lens; dn / dT2 is the temperature coefficient of refractive index of the material of the second lens; Nd3 is the refractive index of the third lens; and Vd3 is the Abbe coefficient of the third lens.

4. A large-aperture broadband imaging lens as described in claim 1 or 3, characterized in that, The second lens and the third lens are cemented together to form a first cemented lens group, satisfying the following condition: Vd2- Vd3>40 In the formula, Vd2 is the Abbe coefficient of the second lens; Vd3 is the Abbe coefficient of the third lens.

5. A large-aperture, wide-spectrum imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: Nd4>1.7; Vd4<30; Nd5>1.95; Vd5 <26 In the formula, Nd4 is the refractive index of the fourth lens; Vd4 is the Abbe coefficient of the fourth lens; Nd5 is the refractive index of the fifth lens; and Vd5 is the Abbe coefficient of the fifth lens.

6. A large-aperture broadband imaging lens as described in claim 1 or 5, characterized in that, The fourth lens and the fifth lens are cemented together to form a second cemented lens group, and satisfy the following condition: Nd5- Nd4>0.25;0.8< Vd5 / Vd4<1 In the formula, Nd4 is the refractive index of the fourth lens; Vd4 is the Abbe coefficient of the fourth lens; Nd5 is the refractive index of the fifth lens; and Vd5 is the Abbe coefficient of the fifth lens.

7. A large-aperture, wide-spectrum imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: Nd6>1.7; Vd6<20; Nd7>1.8; Vd7<25 In the formula, Nd6 is the refractive index of the sixth lens; Vd6 is the Abbe coefficient of the sixth lens; Nd7 is the refractive index of the seventh lens; and Vd7 is the Abbe coefficient of the seventh lens.

8. A large-aperture broadband imaging lens as described in claim 1 or 7, characterized in that, The sixth lens and the seventh lens are cemented together to form a third cemented lens group, and satisfy the following condition: 0.72 < Vd6 / Vd7 < 1 In the formula, Vd6 is the Abbe coefficient of the sixth lens; Vd7 is the Abbe coefficient of the seventh lens.

9. A large-aperture, wide-spectrum imaging lens as described in claim 1, characterized in that, The first lens, the second lens, and the third lens constitute a first lens group; the fourth lens, the fifth lens, the sixth lens, and the seventh lens constitute a second lens group. The lens satisfies the following condition: 3 <fs1 / f<8;0.4<fs2 / f<0.8 0.2 <H / TTL<0.3;0.2<BFL / TTL<0.3 In the formula, fs1 is the focal length of the first lens group; fs2 is the focal length of the second lens group; f is the focal length of the lens; H is the image height; TTL is the total optical length of the lens; and BFL is the optical back focal length of the lens.

10. An electronic device, characterized in that, A large-aperture broadband imaging lens according to any one of claims 1-8; and An image sensor is configured to receive images formed by the large-aperture broadband imaging lens.

Images