Imaging lens

Abstract

The utility model discloses an imaging lens. The imaging lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object side to an image side along an optical axis, the second lens has negative focal power; the third lens has positive focal power; the fourth lens has negative focal power; the fifth lens has positive focal power; the sixth lens has negative focal power; the seventh lens has positive focal power; the eighth lens has negative focal power; the number of the lenses with the focal power of the imaging lens is eight or nine, the imaging lens meets the condition that fIV / f is larger than or equal to-0.8 and smaller than or equal to-0.5, f is the total effective focal length of the imaging lens, and fIV is the combined focal length of the seventh lens and the eighth lens.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical devices, in particular to an imaging lens. BACKGROUND

[0002] An imaging lens is a device composed of one or more lenses, which functions to focus light on an imaging chip, i.e., through a lens or a combination of multiple lenses, light emitted or reflected by an object is imaged on an image plane (coinciding with the imaging chip surface). With the development of science and technology, the market has put forward higher requirements for lenses, especially for imaging lenses. For example, an imaging lens needs to have a long focal length, high resolution, and low distortion. However, the lenses in the related art cannot meet the above requirements. SUMMARY

[0003] In one aspect, the present application provides an imaging lens, which comprises, in order from the object side to the image side along the optical axis, a first lens having positive refractive power, the object side surface of which is convex; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having negative refractive power; a fifth lens having positive refractive power; a sixth lens having negative refractive power; a seventh lens having positive refractive power; and an eighth lens having negative refractive power, the image side surface of which is concave; the number of lenses with refractive power of the imaging lens is eight or nine, and the imaging lens satisfies -0.8≤f IV / f≤-0.5, wherein f is the total effective focal length of the imaging lens, and f IV is the combined focal length of the seventh lens and the eighth lens.

[0004] According to an example embodiment of the present application, the imaging lens further comprises a ninth lens, the ninth lens is located between the third lens and the fourth lens, and the ninth lens has negative refractive power.

[0005] According to an example embodiment of the present application, the imaging lens satisfies at least one of the following: the second lens, the third lens and the ninth lens are cemented to form a second lens group; the fourth lens, the fifth lens and the sixth lens are cemented to form a third lens group; and the seventh lens and the eighth lens are cemented to form a fourth lens group.

[0006] According to an example embodiment of the present application, the imaging lens satisfies at least one of the following: the second lens and the third lens are cemented to form a second lens group; the fourth lens, the fifth lens and the sixth lens are cemented to form a third lens group; and the seventh lens and the eighth lens are cemented to form a fourth lens group.

[0007] According to one exemplary embodiment of the present application, the object side surface of the second lens is convex, the image side surface of the second lens is concave; the object side surface of the third lens is convex; the object side surface of the fourth lens is convex, the image side surface of the fourth lens is concave; the object side surface of the fifth lens is convex, the image side surface of the fifth lens is convex; the object side surface of the sixth lens is concave, the image side surface of the sixth lens is concave; and the object side surface of the seventh lens is convex.

[0008] According to one exemplary embodiment of the present application, the imaging lens satisfies at least one of the following conditional expressions: 1.1≤f1 / f≤1.8, -0.9≤fIII / f≤-0.5, 0.6≤(f4-f5) / fIII≤1.2, -1.65≤fIV / (f7-f8)≤-1.4, where f is a total effective focal length of the imaging lens, f1 is an effective focal length of the first lens, fIII is a combined focal length of the fourth lens, the fifth lens and the sixth lens, f4 is an effective focal length of the fourth lens, f5 is an effective focal length of the fifth lens, fIV is a combined focal length of the seventh lens and the eighth lens, f7 is an effective focal length of the seventh lens, and f8 is an effective focal length of the eighth lens.

[0009] According to one exemplary embodiment of the present application, the imaging lens satisfies at least one of the following conditional expressions: 0.3≤BFL / f≤0.35, 0.35≤BFL / TTL≤0.45, 0.3≤Dmax / TTL≤0.55, 1.3≤f / TTL≤1.5, 2.5≤f / EPD≤3.1, where BFL is a back focal length of the imaging lens, TTL is a total track length of the imaging lens, Dmax is a maximum clear aperture of a lens in the imaging lens, f is a total effective focal length of the imaging lens, and EPD is an entrance pupil diameter of the imaging lens.

[0010] According to one exemplary embodiment of the present application, the imaging lens satisfies at least one of the following conditional expressions: 0.6≤fII / f≤0.75, -6≤fII / (Vd2-Vd3)≤-5, where f is a total effective focal length of the imaging lens, fII is an effective focal length of the second lens group, Vd2 is an Abbe number of the second lens, and Vd3 is an Abbe number of the third lens.

[0011] According to one exemplary embodiment of the present application, the imaging lens satisfies: 1.3≤Vd5 / f5≤1.5, where f5 is an effective focal length of the fifth lens, and Vd5 is an Abbe number of the fifth lens.

[0012] According to one exemplary embodiment of the present application, the imaging lens satisfies at least one of the following conditional expressions: 1.15≤f1 / f≤1.7, -0.85≤fIII / f≤-0.6, -0.7≤fIV / f≤-0.55, 0.8≤(f4-f5) / fIII≤1, -1.6≤fIV / (f7-f8) / fIV≤-1.4, 0.3≤BFL / f≤0.32, 0.4≤BFL / TTL≤0.42, 0.4≤Dmax / TTL≤0.5, 1.3≤f / TTL≤1.35, 2.8≤f / EPD≤3.1, 1.35≤Vd5 / f5≤1.5, where f is the total effective focal length of the imaging lens, f1 is the effective focal length of the first lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, fIII is the combined focal length of the fourth, fifth and sixth lenses, fIV is the combined focal length of the seventh and eighth lenses, Vd5 is the Abbe number of the fifth lens, TTL is the total track length of the imaging lens, BFL is the back focal length of the imaging lens, Dmax is the maximum clear aperture of the lens in the imaging lens, and EPD is the entrance pupil diameter of the imaging lens.

[0013] According to one exemplary embodiment of the present application, the imaging lens satisfies at least one of the following conditional expressions: 0.65≤fII / f≤0.7, -5.55≤fII / (Vd2-Vd3)≤-5.4, where f is the total effective focal length of the imaging lens, fII is the effective focal length of the second lens group, Vd2 is the Abbe number of the second lens, and Vd3 is the Abbe number of the third lens. BRIEF DESCRIPTION OF DRAWINGS

[0014] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments thereof as taken in conjunction with the accompanying drawings. In the drawings:

[0015] Figure 1 A structural schematic diagram of an imaging lens according to Embodiment 1 of the present application is shown;

[0016] Figure 2 A distortion curve of the imaging lens according to Embodiment 1 of the present application is shown;

[0017] Figure 3 A structural schematic diagram of an imaging lens according to Embodiment 2 of the present application is shown;

[0018] Figure 4 A distortion curve of the imaging lens according to Embodiment 2 of the present application is shown;

[0019] Figure 5 A structural schematic diagram of an imaging lens according to Embodiment 3 of the present application is shown;

[0020] Figure 6 A distortion curve of the imaging lens according to Embodiment 3 of the present application is shown;

[0021] Figure 7 A structural schematic diagram of the imaging lens according to Embodiment 4 of the present application is shown; and

[0022] Figure 8 A distortion curve of the imaging lens according to Embodiment 4 of the present application is shown. DETAILED DESCRIPTION

[0023] For better understanding of the present application, various aspects of the present application are described in detail with reference to the drawings. It should be understood that these detailed descriptions are merely descriptive of exemplary embodiments of the present application, and do not limit the scope of the present application in any way.

[0024] In the drawings, the thickness, size, and shape of lenses have been slightly exaggerated for the purpose of illustration. Specifically, the shape of a spherical surface or an aspherical surface shown in the drawings is shown by way of example. That is, the shape of a spherical surface or an aspherical surface is not limited to the shape of a spherical surface or an aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0025] In this document, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0026] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, mean that there are the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or groups thereof. It should be noted that in this specification, the expressions first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. It should be noted that the longitudinal direction stated herein is the direction perpendicular to the optical axis.

[0027] Unless otherwise defined, all terms used in this document have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Terms should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0028] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in the case of no conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0029] The imaging lens according to the exemplary embodiments of the present application can include, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. Any two adjacent lenses among the first lens to the eighth lens can have a separation distance.

[0030] In the exemplary embodiments, the imaging lens can further include a ninth lens between the third lens and the fourth lens.

[0031] In the exemplary embodiments, the second lens and the third lens can form a two-lens group. The fourth lens, the fifth lens, and the sixth lens can form a third lens group. The seventh lens and the eighth lens can form a fourth lens group. In the exemplary embodiments, when the imaging lens includes the ninth lens, the second lens, the third lens, and the ninth lens can form a second lens group.

[0032] In the exemplary embodiments, the first lens can have a positive focal power, and the object side surface thereof can be convex. The first lens having a positive focal power and the object side surface being convex can reduce aberration generated when light enters the optical system while reducing the overall aperture of the first lens. In the exemplary embodiments, the image side surface of the first lens can be concave.

[0033] In the exemplary embodiments, the second lens can have a negative focal power, and the object side surface thereof can be convex, and the image side surface thereof can be concave. In this embodiment, the third lens can have a positive focal power. The second lens having a negative focal power and the third lens having a positive focal power can form a cemented lens group in positive-negative cooperation, which is conducive to correcting chromatic aberration.

[0034] In the exemplary embodiments, the third lens can have a positive focal power, and the object side surface thereof can be convex. The third lens having a positive focal power is conducive to compressing light collected by the front optical system of the imaging lens and making the light transition to the rear optical system gently, thereby reducing system sensitivity and increasing the aperture. In the exemplary embodiments, the image side surface of the third lens can be concave or convex.

[0035] In the exemplary embodiments, the ninth lens can have a negative focal power, and the object side surface thereof can be concave, and the image side surface thereof can be concave. In this embodiment, the second lens can have a negative focal power, and the third lens can have a positive focal power. The second lens, the third lens, and the ninth lens having a negative focal power can form a three-cemented lens group in negative-positive-negative cooperation, which is conducive to compensating for aberration generated by the front lens group and improving image quality.

[0036] In an exemplary embodiment, the fourth lens can have a negative focal power, the object side surface thereof can be convex, and the image side surface thereof can be concave. In this embodiment, the fifth lens can have a positive focal power, and the sixth lens can have a negative focal power, so that the fourth lens, the sixth lens, and the fifth lens with a positive focal power are arranged in a negative-positive-negative manner to form a three-cemented lens group, which is conducive to correcting chromatic aberration, improving image quality, effectively and gently lifting light, and reducing the tolerance sensitivity of the system, thereby improving the lens assembly yield.

[0037] In an exemplary embodiment, the fifth lens can have a positive focal power, the object side surface thereof can be convex, and the image side surface thereof can be convex. In this embodiment, the sixth lens can have a negative focal power, and the fourth lens can have a negative focal power, so that the fourth lens, the sixth lens, and the fifth lens with a positive focal power are arranged in a negative-positive-negative manner to form a three-cemented lens group, which is conducive to correcting chromatic aberration, improving image quality, effectively and gently lifting light, and reducing the tolerance sensitivity of the system, thereby improving the lens assembly yield.

[0038] In an exemplary embodiment, the sixth lens can have a negative focal power, the object side surface thereof can be concave, and the image side surface thereof can be concave. In this embodiment, the fourth lens can have a negative focal power, and the fifth lens can have a positive focal power, so that the fourth lens, the fifth lens, and the sixth lens with a negative focal power are arranged in a negative-positive-negative manner to form a three-cemented lens group, which is conducive to correcting chromatic aberration, improving image quality, effectively and gently lifting light, and reducing the tolerance sensitivity of the system, thereby improving the lens assembly yield.

[0039] In an exemplary embodiment, the seventh lens can have a positive focal power, and the object side surface thereof can be convex. The seventh lens has a positive focal power, and the object side surface thereof is convex, which is conducive to correcting chromatic aberration and residual aberration, and effectively controlling the trend of light to lift the light, thereby improving the height of the imaging surface. In an exemplary embodiment, the image side surface of the seventh lens can be a plane or a concave surface.

[0040] In an exemplary embodiment, the eighth lens can have a negative focal power, and the image side surface thereof can be concave. The eighth lens has a negative focal power, and the image side surface thereof is concave, which is conducive to correcting residual aberration, and effectively controlling the trend of light to lift the light, so that the light better matches the height of the imaging surface, and further improves the relative luminance.

[0041] In the present application, since the image side surface of the first lens, the image side surface of the seventh lens, and the object side surface of the eighth lens have relatively large radii of curvature, the above-mentioned side surfaces can be convex, planar, or concave, and are variable, so that the lens surface shape can be set as needed.

[0042] The imaging lens provided by the embodiments of the present application can realize low distortion (DIS≤0.2%) by making the first lens have positive refractive power, the second lens have negative refractive power, the third lens have positive refractive power, the fourth lens have negative refractive power, the fifth lens have positive refractive power, the sixth lens have negative refractive power, the seventh lens have positive refractive power, and the eighth lens have negative refractive power.

[0043] In the example embodiments, the imaging lens can further include a stop. The stop can be located on the object side of the first lens, thereby effectively reducing the front aperture and the optical aberration of the imaging lens.

[0044] In the example embodiments, the imaging lens can further include a filter for correcting color deviation.

[0045] In the example embodiments, the total effective focal length f of the imaging lens can satisfy: f≥190mm, and further, f can be 198-200mm, thereby realizing the long-focus requirement of the imaging lens.

[0046] In the example embodiments, any one of the first lens to the ninth lens can be a glass lens or a plastic lens. The glass lens can effectively suppress the shift of the back focal length of the imaging lens due to temperature change, thereby improving the stability of the imaging lens. Meanwhile, the glass lens can effectively avoid the imaging blur caused by high-temperature environment or low-temperature environment, thereby ensuring the normal use of the imaging lens and being conducive to realizing the athermalization of the imaging lens and correcting the system chromatic aberration and improving the resolving power of the imaging lens. The plastic lens can effectively reduce the cost of the imaging lens. As an example, any one of the first lens to the ninth lens is a glass lens, which is conducive to improving the imaging quality and reliability of the imaging lens. For example, when the first lens to the ninth lens are all glass lenses, the working temperature range of the imaging lens is wide, and the optical performance of the imaging lens can be kept stable within the range of -30°C to 75°C. As an example, part of the first lens to the ninth lens is a glass lens, and the remaining part is a plastic lens. The imaging lens adopts the form of glass-plastic hybrid, which can effectively reduce the cost of the imaging lens.

[0047] In the example embodiments, the imaging lens can satisfy: 1.1≤f1 / f≤1.8, where f is the total effective focal length of the imaging lens, and f1 is the effective focal length of the first lens. By making the imaging lens satisfy the above condition, the ratio range of the effective focal length of the first lens to the total effective focal length is controlled, which can reduce the overall aperture of the imaging lens and the aberration caused by the light entering the optical system. Preferably, the imaging lens can further satisfy: 1.15≤f1 / f≤1.7, which is more conducive to realizing the reduction of aberration of the imaging lens and reducing the size of the lens and the front end of the lens.

[0048] In exemplary embodiments, the imaging lens can satisfy: 0.6≤f II / f≤0.75, where f II is the effective focal length of the second lens group, and f is the total effective focal length of the imaging lens. By making the imaging lens satisfy the above condition, the ratio of the effective focal length of the second lens group and the total effective focal length is controlled in a range, which can effectively control the light path, lower the height of the outgoing light, and thus be beneficial to reduce the chromatic aberration of the optical system, improve the resolving power of the lens, and reduce the total optical length of the imaging lens. Preferably, the imaging lens can further satisfy: 0.65≤f II / f≤0.7, which is more beneficial to reduce the aberration of the imaging lens, improve the resolving power, and reduce the total optical length.

[0049] In exemplary embodiments, the imaging lens can satisfy: -0.9≤f III / f≤-0.5, where f III is the combined focal length of the fourth lens, the fifth lens, and the sixth lens, and f is the total effective focal length of the imaging lens. By making the imaging lens satisfy the above condition, the ratio of the effective focal length of the third lens group and the total effective focal length is controlled in a range, which is beneficial to correct the chromatic aberration, improve the image quality, effectively and gently raise the light, reduce the tolerance sensitivity of the system, and be beneficial to improve the assembly yield of the imaging lens. Preferably, the imaging lens can further satisfy: -0.85≤f III / f≤-0.6, which is more beneficial to reduce the aberration of the imaging lens, improve the resolving power, and reduce the total optical length.

[0050] In exemplary embodiments, the imaging lens can satisfy: -0.8≤f IV / f≤-0.5, where f is the total effective focal length of the imaging lens, and f IV is the combined focal length of the seventh lens and the eighth lens. By making the imaging lens satisfy the above condition, the ratio of the effective focal length of the fourth lens group and the total effective focal length is controlled in a range, which is beneficial to correct the remaining aberration, improve the resolving power, effectively control the light path, raise the light, make the light better match the image height, further increase the focal length of the system, and improve the relative illumination. Preferably, the imaging lens can further satisfy: -0.7≤f IV / f≤-0.55, which is more beneficial to reduce the aberration of the imaging lens, improve the resolving power, and improve the focal length.

[0051] In exemplary embodiments, the imaging lens can satisfy: -6≤f II / (Vd2-Vd3)≤-5, where f II is the effective focal length of the second lens group, Vd2 is the Abbe number of the second lens, and Vd3 is the Abbe number of the third lens. By making the imaging lens satisfy the above condition, the lens material of the second lens and the third lens is reasonably selected, and the ratio between the effective focal length of the second lens group and the difference between the Abbe number of the second lens and the Abbe number of the third lens is reasonably configured, which can effectively correct the system chromatic aberration and improve the resolving power of the imaging lens. Preferably, the imaging lens can further satisfy: -5.55≤f II / (Vd2-Vd3)≤-5.4, which is more conducive to correcting the chromatic aberration of the imaging lens and achieving high resolving power.

[0052] In exemplary embodiments, the imaging lens can satisfy: 0.6≤(f4-f5) / f III≤1.2, where f III is the combined focal length of the fourth lens, the fifth lens and the sixth lens, f4 is the effective focal length of the fourth lens, and f5 is the effective focal length of the fifth lens. By making the imaging lens satisfy the above condition, the ratio between the difference between the effective focal length of the fourth lens and the effective focal length of the fifth lens and the effective focal length of the third lens group is reasonably configured, which is conducive to reducing the aberration of the optical system and improving the resolving power of the imaging lens. Preferably, the imaging lens can further satisfy: 0.8≤(f4-f5) / f III≤1, which is more conducive to correcting the chromatic aberration of the imaging lens and achieving high resolving power.

[0053] In exemplary embodiments, the imaging lens can satisfy: -1.65≤f IV / (f7-f8)≤-1.4, where f IV is the combined focal length of the seventh lens and the eighth lens, f7 is the effective focal length of the seventh lens, and f8 is the effective focal length of the eighth lens. By making the imaging lens satisfy the above condition, the effective focal length of the seventh lens and the eighth lens in the fourth lens group is reasonably configured, which is conducive to reducing the aberration and tolerance sensitivity of the optical system, improving the resolving power of the imaging lens, and better matching the light rays with the imaging surface height, ensuring that the height requirement of the image side can be met, and further improving the relative luminance of the imaging lens. Preferably, the imaging lens can further satisfy: -1.6≤f IV / (f7-f8) / f IV≤-1.4, which is more conducive to correcting the chromatic aberration of the imaging lens and achieving high resolving power.

[0054] In the example embodiments, the imaging lens can satisfy: 0.3≤BFL / f≤0.35, where f is the total effective focal length of the imaging lens, and BFL is the back focal length of the imaging lens. By making the imaging lens satisfy the above condition, the length of the optical back focal length of the imaging lens is controlled so that the back focal length of the imaging lens is longer, which helps to reserve space for the installation of optical elements, thereby facilitating the assembly of the imaging lens, avoiding interference between components, and thus improving the assembly yield of the imaging lens, and further compensating for high and low temperatures.

[0055] In the example embodiments, the imaging lens can satisfy: 0.35≤BFL / TTL≤0.45, where BFL is the back focal length of the imaging lens, and TTL is the total optical length of the imaging lens. By making the imaging lens satisfy the above condition, the ratio of the optical back focal length to the total optical length of the imaging lens is controlled, which can further constrain the total optical length of the imaging lens while meeting the imaging requirements of the imaging lens, and achieve miniaturization of the imaging lens. Preferably, the imaging lens can further satisfy: 0.4≤BFL / TTL≤0.42, which is more conducive to achieving miniaturization of the overall structure of the imaging lens.

[0056] In the example embodiments, the imaging lens can satisfy: 0.3≤Dmax / TTL≤0.55, where TTL is the total optical length of the imaging lens, and Dmax is the maximum light passing full aperture of the lens in the imaging lens. By making the imaging lens satisfy the above condition, the maximum aperture at the front end of the imaging lens and the total optical length are reasonably constrained, which is conducive to reducing the overall size of the imaging lens and making the entire imaging lens more compact to achieve miniaturization. Preferably, the imaging lens can further satisfy: 0.4≤Dmax / TTL≤0.5, which is more conducive to achieving miniaturization of the size of the imaging lens.

[0057] In the example embodiments, the imaging lens can satisfy: 1.3≤f / TTL≤1.5, where TTL is the total optical length of the imaging lens, and f is the total effective focal length of the imaging lens. By making the imaging lens satisfy the above condition, the total optical length of the imaging lens and the effective focal length of the system are reasonably adjusted, which is conducive to making the entire imaging lens more compact to achieve miniaturization. Preferably, the imaging lens can further satisfy: 1.3≤f / TTL≤1.35, which is more conducive to achieving miniaturization of the size of the imaging lens.

[0058] In an exemplary embodiment, the imaging lens may satisfy the following condition: 2.5 ≤ f / EPD ≤ 3.1, where f is the total effective focal length of the imaging lens and EPD is the entrance pupil diameter of the imaging lens. By ensuring that the imaging lens satisfies this condition, the entrance pupil diameter of the imaging lens can be properly controlled, thereby facilitating an increase in aperture and improving the illumination of the imaging lens. Preferably, the imaging lens may further satisfy the following condition: 2.8 ≤ f / EPD ≤ 3.1, further facilitating a limited aperture for the imaging lens.

[0059] In an exemplary embodiment, the imaging lens may satisfy the following equation: 1.3 ≤ Vd5 / f5 ≤ 1.5, where f5 is the effective focal length of the fifth lens element and Vd5 is the Abbe number of the fifth lens element. By ensuring that the imaging lens satisfies this conditional equation, appropriately selecting the lens material for the fifth lens element, and properly configuring the ratio of the fifth lens element's Abbe number to its effective focal length, systematic chromatic aberration can be effectively corrected, thereby improving the resolution of the imaging lens. Preferably, the imaging lens may further satisfy the following equation: 1.35 ≤ Vd5 / f5 ≤ 1.5, further facilitating chromatic aberration correction and achieving high resolution.

[0060] The imaging lens according to the above-mentioned embodiment of the present application can adopt multiple lenses, such as the nine lenses mentioned above. By rationally allocating optical parameters such as the optical power and surface shape of each lens, it is possible to achieve at least one of high resolution (4K), chromatic aberration correction, miniaturization, aberration reduction, low distortion (optical distortion DIS ≤ 0.2%), large depth of field, high illumination (relative illumination ≥ 99%), telephoto (focal length ≥ 190mm, up to 200mm), and high and low temperature resistance (capable of continuous operation for a long time under high and low temperature conditions of -30 to +70°C).

[0061] However, those skilled in the art will appreciate that, without departing from the technical solution claimed in the present application, the number of lenses constituting the imaging lens may be changed to obtain the various results and advantages described in this specification.

[0062] Specific embodiments of imaging lenses applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0063] Example 1

[0064] The following reference Figure 1 An imaging lens according to Embodiment 1 of the present application is described. Figure 1 Schematic diagram of the structure of an imaging lens according to Example 1 of the present application.

[0065] like Figure 1As shown, the imaging lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8. A stop STO is disposed on the object side of the first lens L1. The second lens L2 and the third lens L3 are cemented to form a second lens group. The fourth lens L4, the fifth lens L5, and the sixth lens L6 are cemented to form a third lens group. The seventh lens L7 and the eighth lens L8 are cemented to form a fourth lens group.

[0066] The first lens L1 has positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface.

[0067] The second lens L2 has negative refractive power, the object side surface S3 is a convex surface, and the image side surface S4 is a concave surface.

[0068] The third lens L3 has positive refractive power, the object side surface S4 is a convex surface, and the image side surface S5 is a concave surface.

[0069] The fourth lens L4 has negative refractive power, the object side surface S6 is a convex surface, and the image side surface S7 is a concave surface.

[0070] The fifth lens L5 has positive refractive power, the object side surface S7 is a convex surface, and the image side surface S8 is a convex surface.

[0071] The sixth lens L6 has negative refractive power, the object side surface S8 is a concave surface, and the image side surface S9 is a concave surface.

[0072] The seventh lens L7 has positive refractive power, the object side surface S10 is a convex surface, and the image side surface S11 is a plane or a concave surface.

[0073] The eighth lens L8 has negative refractive power, the object side surface S11 is a plane or a convex surface, and the image side surface S12 is a concave surface.

[0074] In this embodiment, since the curvature radiuses of the image side surface S2 of the first lens L1, the image side surface S11 of the seventh lens L7, and the object side surface S11 of the eighth lens L8 are large, the above-mentioned side surfaces can be convex, plane, or concave, and have variability, which can be set according to actual needs.

[0075] The imaging lens further includes a filter CG disposed on the image side of the eighth lens L8, which has an object side surface S13 and an image side surface S14.

[0076] Light from an object sequentially passes through each surface S1-S14 and is finally imaged on an imaging surface IMA. It should be noted that the surfaces S1-S14 are not shown in Figure 1 .

[0077] Table 1 shows a basic parameter table of the imaging lens of Embodiment 1, wherein the units of the curvature radius and the thickness / distance are millimeters (mm).

[0078]

[0079]

[0080] Table 1

[0081] In this embodiment, the aperture number Fno of the imaging lens is set to 3. The maximum field angle of the imaging lens corresponds to an image height of 7.88 mm, and the relative illumination is 99.15%.

[0082] Figure 2 The distortion curve of the imaging lens of Example 1 is shown in FIG. Figure 2 As shown in FIG. 1 , the maximum optical distortion DIS of the imaging lens of Example 1 is 0.18%. Therefore, the imaging lens of Example 1 can achieve good imaging quality.

[0083] Example 2

[0084] The following reference Figure 3 An imaging lens according to Example 2 of the present application will be described. Figure 3 Schematic diagram of the structure of an imaging lens according to Example 2 of the present application.

[0085] like Figure 3 As shown, the imaging lens includes, from the object side to the image side along the optical axis, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, and eighth lens L8. A stop STO is located on the object side of first lens L1. Second lens L2 and third lens L3 are cemented together to form the second lens group. Fourth lens L4, fifth lens L5, and sixth lens L6 are cemented together to form the third lens group. Seventh lens L7 and eighth lens L8 are cemented together to form the fourth lens group.

[0086] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0087] The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave.

[0088] The third lens L3 has positive refractive power, its object-side surface S4 is convex, and its image-side surface S5 is concave.

[0089] The fourth lens L4 has negative refractive power, its object-side surface S6 is convex, and its image-side surface S7 is concave.

[0090] The fifth lens L5 has positive refractive power, and its object-side surface S7 and image-side surface S8 are convex.

[0091] The sixth lens L6 has negative refractive power, and its object-side surface S8 and image-side surface S9 are concave.

[0092] The seventh lens L7 has positive refractive power, the object side surface S10 is a convex surface, and the image side surface S11 is a plane or a concave surface.

[0093] The eighth lens L8 has negative refractive power, the object side surface S11 is a plane or a convex surface, and the image side surface S12 is a concave surface.

[0094] In the present embodiment, since the curvature radius of the image side surface S2 of the first lens L1, the image side surface S11 of the seventh lens L7, and the object side surface S11 of the eighth lens L8 are large, the above-mentioned side surfaces can be convex, plane or concave, with variability.

[0095] The imaging lens further comprises a filter CG disposed on the image side of the eighth lens L8, which has an object side surface S13 and an image side surface S14.

[0096] Light from the object sequentially passes through each surface S1-S14 and is finally imaged on the imaging plane IMA. It should be noted that the surfaces S1-S14 are not shown in Figure 1 .

[0097] Table 2 shows the basic parameter table of the imaging lens of embodiment 2, wherein the units of the curvature radius, thickness / distance are all millimeters (mm).

[0098]

[0099]

[0100] Table 2

[0101] In the present embodiment, the value of the aperture number Fno of the imaging lens is 2.9. The maximum field angle of the imaging lens corresponds to an image height of 7.88 mm, and the relative luminance is 99.19%.

[0102] Figure 4 The distortion curve of the imaging lens of embodiment 2 is shown in FIG. 6, as shown in Figure 4 , the maximum optical distortion DIS of the imaging lens of embodiment 2 is 0.17%. Therefore, the imaging lens given in embodiment 2 can achieve good imaging quality.

[0103] Embodiment 3

[0104] The imaging lens according to embodiment 3 of the present application is described below with reference to Figure 5 . Figure 5 FIG. 1 is a structural schematic diagram of the imaging lens according to embodiment 3 of the present application.

[0105] As shown in Figure 5As shown, the imaging lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a ninth lens L9, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8. A stop STO is disposed on the object side of the first lens L1. The second lens L2, the third lens L3, and the ninth lens L9 are cemented to form a second lens group. The fourth lens L4, the fifth lens L5, and the sixth lens L6 are cemented to form a third lens group. The seventh lens L7 and the eighth lens L8 are cemented to form a fourth lens group.

[0106] The first lens L1 has positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface.

[0107] The second lens L2 has negative refractive power, the object side surface S3 is a convex surface, and the image side surface S4 is a concave surface.

[0108] The third lens L3 has positive refractive power, the object side surface S4 is a convex surface, and the image side surface S5 is a convex surface.

[0109] The ninth lens L9 has negative refractive power, the object side surface S5 is a concave surface, and the image side surface S6 is a concave surface.

[0110] The fourth lens L4 has negative refractive power, the object side surface S7 is a convex surface, and the image side surface S8 is a concave surface.

[0111] The fifth lens L5 has positive refractive power, the object side surface S8 is a convex surface, and the image side surface S9 is a convex surface.

[0112] The sixth lens L6 has negative refractive power, the object side surface S9 is a concave surface, and the image side surface S10 is a concave surface.

[0113] The seventh lens L7 has positive refractive power, the object side surface S11 is a convex surface, and the image side surface S12 is a plane or a concave surface.

[0114] The eighth lens L8 has negative refractive power, the object side surface S12 is a plane or a convex surface, and the image side surface S13 is a concave surface.

[0115] In this embodiment, since the image side surface S2 of the first lens L1, the image side surface S12 of the seventh lens L7, and the object side surface S12 of the eighth lens L8 have relatively large radii of curvature, the above-mentioned surfaces can be convex, plane, or concave, and have variability, which can be set according to actual needs.

[0116] The imaging lens further includes a filter CG disposed on the image side of the eighth lens L8, which has an object side surface S14 and an image side surface S15.

[0117] Light from an object passes through the surfaces S1-S15 in order and is finally imaged on an imaging plane IMA. It should be noted that the surfaces S1-S15 are not shown in Figure 5 .

[0118] Table 3 shows the basic parameters of the imaging lens of Example 3, where the units of curvature radius and thickness / distance are all millimeters (mm).

[0119]

[0120] Table 3

[0121] In this embodiment, the aperture number Fno of the imaging lens is set to 2.9. The maximum field angle of the imaging lens corresponds to an image height of 7.88 mm and a relative illumination of 99.21%.

[0122] Figure 6 The distortion curve of the imaging lens of Example 3 is shown in FIG. Figure 6 As shown in FIG. 3 , the maximum optical distortion DIS of the imaging lens of Example 3 is 0.17%. Therefore, the imaging lens of Example 3 can achieve good imaging quality.

[0123] Example 4

[0124] The following reference Figure 7 An imaging lens according to Example 4 of the present application will be described. Figure 7 Schematic diagram of the structure of an imaging lens according to Example 4 of the present application.

[0125] like Figure 7 As shown, the imaging lens includes, from the object side to the image side along the optical axis, first lens L1, second lens L2, third lens L3, ninth lens L9, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, and eighth lens L8. A stop STO is located on the object side of first lens L1. Second lens L2, third lens L3, and ninth lens L9 are cemented together to form the second lens group. Fourth lens L4, fifth lens L5, and sixth lens L6 are cemented together to form the third lens group. Seventh lens L7 and eighth lens L8 are cemented together to form the fourth lens group.

[0126] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0127] The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave.

[0128] The third lens L3 has positive refractive power, and its object-side surface S4 and image-side surface S5 are convex.

[0129] The ninth lens L9 has negative refractive power, and its object-side surface S5 and image-side surface S6 are concave.

[0130] The fourth lens L4 has negative refractive power, its object-side surface S7 is convex, and its image-side surface S8 is concave.

[0131] The fifth lens L5 has positive refractive power, the object side S8 is a convex surface, and the image side S9 is a convex surface.

[0132] The sixth lens L6 has negative refractive power, the object side S9 is a concave surface, and the image side S10 is a concave surface.

[0133] The seventh lens L7 has positive refractive power, the object side S11 is a convex surface, and the image side S12 is a plane or a concave surface.

[0134] The eighth lens L8 has negative refractive power, the object side S12 is a plane or a convex surface, and the image side S13 is a concave surface.

[0135] In the present embodiment, since the curvature radius of the image side S2 of the first lens L1, the image side S12 of the seventh lens L7, and the object side S12 of the eighth lens L8 is large, the above-mentioned side surface can be a convex surface, a plane, or a concave surface, which has variability and can be set according to actual needs.

[0136] The imaging lens further includes a filter CG disposed on the image side of the eighth lens L8, which has an object side S14 and an image side S15.

[0137] Light from the object sequentially passes through each surface S1-S15 and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1-S15 are not shown in Figure 7 .

[0138] Table 4 shows the basic parameter table of the imaging lens of embodiment 4, wherein the units of the curvature radius and the thickness / distance are millimeters (mm).

[0139]

[0140] Table 4

[0141] In the present embodiment, the value of the aperture number Fno of the imaging lens is 3.1. The maximum field angle of the imaging lens corresponds to an image height of 7.88 mm, and the relative luminance is 99.23%.

[0142] Figure 8 The distortion curve of the imaging lens of embodiment 4 is shown, as shown in Figure 8 , the maximum optical distortion DIS of the imaging lens of embodiment 4 is 0.16%. Therefore, the imaging lens given in embodiment 4 can achieve good imaging quality.

[0143] In summary, the conditional expressions in embodiments 1 to 4 satisfy the relationships shown in Table 5. In Table 5, f, EPD, TTL, BFL, f1, f4, f5, f7, f8, fII-fIV, Dmax are in units of millimeters (mm).

[0144]

[0145] Table 6

[0146] The present application also provides an imaging device, whose electronic photosensitive element can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor device (CMOS), which is equipped with the imaging lens described above.

[0147] The above description is merely preferred embodiments of the present application and a description of the technical principles of the application. It should be understood by those skilled in the art that the scope of the utility model disclosed in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by the combinations of the above technical features or equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. An imaging lens, characterized in that: Along the optical axis from the object side to the image side, they include: a first lens having positive optical power and a convex object-side surface; a second lens having negative optical power; a third lens having positive optical power; a fourth lens element having negative optical power; a fifth lens having positive refractive power; a sixth lens having negative optical power; a seventh lens having positive optical power; and an eighth lens element having negative optical power and a concave image-side surface; The number of lenses having optical power in the imaging lens is eight or nine, and the imaging lens satisfies: -0.8≤fⅣ / f≤-0.5, Wherein, f is the total effective focal length of the imaging lens, and fIV is the combined focal length of the seventh lens and the eighth lens.

2. The imaging lens according to claim 1, wherein: The imaging lens further includes a ninth lens, which is located between the third lens and the fourth lens and has negative optical power.

3. The imaging lens according to claim 2, wherein: The imaging lens satisfies at least one of the following conditions: The second lens, the third lens and the ninth lens are cemented together to form a second lens group; The fourth lens, the fifth lens and the sixth lens are cemented together to form a third lens group; and The seventh lens and the eighth lens are cemented together to form a fourth lens group.

4. The imaging lens according to claim 1, wherein: The imaging lens satisfies at least one of the following conditions: The second lens and the third lens are cemented together to form a second lens group; The fourth lens, the fifth lens and the sixth lens are cemented together to form a third lens group; and The seventh lens and the eighth lens are cemented together to form a fourth lens group.

5. The imaging lens according to claim 1, wherein: The object side surface of the second lens is convex, and the image side surface is concave; The object side surface of the third lens is a convex surface; The object-side surface of the fourth lens is convex, and the image-side surface is concave; The object-side surface of the fifth lens is convex, and the image-side surface is convex; The object-side surface and image-side surface of the sixth lens are concave; and The object-side surface of the seventh lens is convex.

6. The imaging lens according to any one of claims 1 to 5, wherein: The imaging lens satisfies at least one of the following conditions: 1.1≤f1 / f≤1.8, -0.9≤fⅢ / f≤-0.5, 0.6≤(f4-f5) / fⅢ≤1.2, -1.65≤fⅣ / (f7-f8)≤-1.4, Among them, f is the total effective focal length of the imaging lens, f1 is the effective focal length of the first lens, fIII is the combined focal length of the fourth lens, the fifth lens and the sixth lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, fIV is the combined focal length of the seventh lens and the eighth lens, f7 is the effective focal length of the seventh lens, and f8 is the effective focal length of the eighth lens.

7. The imaging lens according to any one of claims 1 to 5, wherein: The imaging lens satisfies at least one of the following conditions: 0.3≤BFL / f≤0.35, 0.35≤BFL / TTL≤0.45, 0.3≤Dmax / TTL≤0.55, 1.3≤f / TTL≤1.5, 2.5≤f / EPD≤3.1, Wherein, BFL is the back focal length of the imaging lens, TTL is the total optical length of the imaging lens, Dmax is the maximum clear aperture of the lens in the imaging lens, f is the total effective focal length of the imaging lens, and EPD is the entrance pupil diameter of the imaging lens.

8. The imaging lens according to claim 3 or 4, wherein: The imaging lens satisfies at least one of the following conditions: 0.6≤fⅡ / f≤0.75, -6≤fII / (Vd2-Vd3)≤-5, Wherein, f is the total effective focal length of the imaging lens, fII is the effective focal length of the second lens group, Vd2 is the Abbe number of the second lens, and Vd3 is the Abbe number of the third lens.

9. The imaging lens according to any one of claims 1 to 5, wherein: The imaging lens satisfies: 1.3≤Vd5 / f5≤1.5, Wherein, f5 is the effective focal length of the fifth lens, and Vd5 is the Abbe number of the fifth lens.

10. The imaging lens according to any one of claims 1 to 5, wherein: The imaging lens satisfies at least one of the following conditions: 1.15≤f1 / f≤1.7, -0.85≤fⅢ / f≤-0.6, -0.7≤fⅣ / f≤-0.55, 0.8≤(f4-f5) / fⅢ≤1, -1.6≤fⅣ / (f7-f8) / fⅣ≤-1.4, 0.3 ≤BFL / f≤0.32, 0.4≤BFL / TTL≤0.42, 0.4≤Dmax / TTL≤0.5, 1.3≤f / TTL≤1.35, 2.8≤f / EPD≤3.1, 1.35≤Vd5 / f5≤1.5, Wherein, f is the total effective focal length of the imaging lens, f1 is the effective focal length of the first lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, fIII is the combined focal length of the fourth lens, the fifth lens and the sixth lens, fIV is the combined focal length of the seventh lens and the eighth lens, Vd5 is the Abbe number of the fifth lens, TTL is the total optical length of the imaging lens, BFL is the back focal length of the imaging lens, Dmax is the maximum clear aperture of the lenses in the imaging lens, and EPD is the entrance pupil diameter of the imaging lens.

11. The imaging lens according to claim 3 or 4, characterized in that: The imaging lens satisfies at least one of the following conditions: 0.65≤fⅡ / f≤0.7, -5.55≤fII / (Vd2-Vd3)≤-5.4, wherein f is the total effective focal length of the imaging lens, fⅡ is the effective focal length of the second lens group, Vd2 is the Abbe number of the second lens, and Vd3 is the Abbe number of the third lens.

Images