Imaging lens

Abstract

The invention 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, and in particular to an imaging lens. Background Art

[0002] An imaging lens is a device composed of one or more lenses. Its function is to focus light onto an imaging chip, that is, to image the light emitted or reflected by an object onto an image plane (coinciding with the imaging chip surface) through a lens or a combination of multiple lenses. With the development of science and technology, the market has put forward higher requirements for lenses, especially for imaging lenses. For example, imaging lenses need to have long focal lengths, high resolution capabilities, and low distortion. However, the lenses in related technologies cannot meet the above requirements. Summary of the invention

[0003] On the one hand, the present application provides an imaging lens, which includes, in order from the object side to the image side along the optical axis, a first lens with positive optical power; a second lens with negative optical power; a third lens with positive optical power; a fourth lens with negative optical power; a fifth lens with positive optical power; a sixth lens with negative optical power; a seventh lens with positive optical power; and an eighth lens with negative optical power; the number of lenses with 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.

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

[0005] According to an exemplary embodiment of the present application, the object-side surface of the first lens is a convex surface; and the image-side surface of the eighth lens is a concave surface.

[0006] According to an exemplary embodiment of the present application, the second lens, the third lens and the ninth lens are cemented together to form a second lens group.

[0007] According to an exemplary embodiment of the present application, the second lens and the third lens are cemented together to form a second lens group.

[0008] According to an exemplary embodiment of the present application, the seventh lens and the eighth lens are cemented to form a fourth lens group.

[0009] According to an exemplary embodiment of the present application, the fourth lens, the fifth lens and the sixth lens are cemented to form a third lens group.

[0010] According to an exemplary embodiment of the present application, 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 convex; 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 of the sixth lens is concave, and the image side surface is concave; and the object side surface of the seventh lens is convex.

[0011] According to an exemplary embodiment of the present application, the imaging lens satisfies: 1.1≤f1 / f≤1.8, wherein f is the total effective focal length of the imaging lens, and f1 is the effective focal length of the first lens.

[0012] According to an exemplary embodiment of the present application, the imaging lens satisfies: 0.6≤fⅡ / f≤0.75, wherein fⅡ is the effective focal length of the second lens group, and f is the total effective focal length of the imaging lens.

[0013] According to an exemplary embodiment of the present application, the imaging lens satisfies: -0.9≤fⅢ / f≤-0.5, wherein fⅢ 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.

[0014] According to an exemplary embodiment of the present application, the imaging lens satisfies: -6≤fII / (Vd2-Vd3)≤-5, wherein 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.

[0015] According to an exemplary embodiment of the present application, the imaging lens satisfies: 0.6≤(f4-f5) / fⅢ≤1.2, wherein 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, and f5 is the effective focal length of the fifth lens.

[0016] According to an exemplary embodiment of the present application, the imaging lens satisfies: -1.65≤fⅣ / (f7-f8)≤-1.4, wherein fⅣ is the effective focal length of the fourth lens group, f7 is the effective focal length of the seventh lens, and f8 is the effective focal length of the eighth lens.

[0017] According to an exemplary embodiment of the present application, the imaging lens satisfies: 0.3≤BFL / f≤0.35, wherein f is the total effective focal length of the imaging lens, and BFL is the back focal length of the imaging lens.

[0018] According to an exemplary embodiment of the present application, the imaging lens satisfies: 0.35≤BFL / TTL≤0.45, wherein BFL is the back focal length of the imaging lens, and TTL is the total optical length of the imaging lens.

[0019] According to an exemplary embodiment of the present application, the imaging lens satisfies: 0.3≤Dmax / TTL≤0.55, wherein TTL is the total optical length of the imaging lens, and Dmax is the maximum clear aperture of the lens in the imaging lens.

[0020] According to an exemplary embodiment of the present application, the imaging lens satisfies: 1.3≤f / TTL≤1.5, wherein TTL is the total optical length of the imaging lens, and f is the total effective focal length of the imaging lens.

[0021] According to an exemplary embodiment of the present application, the imaging lens satisfies: 2.5≤f / EPD≤3.1, wherein f is the total effective focal length of the imaging lens, and EPD is the entrance pupil diameter of the imaging lens.

[0022] According to an exemplary embodiment of the present application, 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.

[0023] According to an exemplary embodiment of the present application, the imaging lens satisfies at least one of the following conditional formulas: 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≤Vd 5 / 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 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 lens in the imaging lens, and EPD is the entrance pupil diameter of the imaging lens.

[0024] According to an exemplary embodiment of the present application, the imaging lens satisfies at least one of the following conditional formulas: 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings. In the drawings:

[0026] Figure 1 A schematic structural diagram of an imaging lens according to Embodiment 1 of the present application is shown;

[0027] Figure 2 shows a distortion curve of the imaging lens according to Example 1 of the present application;

[0028] Figure 3 A schematic structural diagram of an imaging lens according to Embodiment 2 of the present application is shown;

[0029] Figure 4 shows a distortion curve of an imaging lens according to Embodiment 2 of the present application;

[0030] Figure 5 A schematic structural diagram of an imaging lens according to Embodiment 3 of the present application is shown;

[0031] Figure 6 shows a distortion curve of an imaging lens according to Embodiment 3 of the present application;

[0032] Figure 7 A schematic structural diagram of an imaging lens according to Embodiment 4 of the present application is shown; and

[0033] Figure 8 The distortion curve of the imaging lens according to Example 4 of the present application is shown. DETAILED DESCRIPTION

[0034] In order to better understand the present application, various aspects of the present application are described in detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way.

[0035] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0036] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0037] It should also be understood that the terms "include", "comprising", "having", "including" and / or "comprising", when used in this specification, indicate the presence of 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 combinations thereof. It should be noted that in this specification, the expressions first, second, third, etc. are only used to distinguish one feature from another, 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.

[0038] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. Terms should be interpreted as having the same meaning as they have in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] The imaging lens according to the exemplary embodiment of the present application may include 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 arranged in sequence from the object side to the image side along the optical axis. Any two adjacent lenses among the first lens to the eighth lens may have a spacing distance therebetween.

[0041] In example embodiments, the imaging lens may further include a ninth lens located between the third lens and the fourth lens.

[0042] In an exemplary embodiment, the second lens and the third lens may be cemented to form a second lens group. The fourth lens, the fifth lens, and the sixth lens may be cemented to form a third lens group. The seventh lens and the eighth lens may be cemented to form a fourth lens group lens. In an exemplary embodiment, when the imaging lens includes a ninth lens, the second lens, the third lens, and the ninth lens may be cemented to form a second lens group.

[0043] In an exemplary embodiment, the first lens may have positive power, and its object side surface may be convex. The first lens has positive power, and its object side surface is convex, which can reduce the aberration caused by light entering the optical system while reducing the overall aperture of the first lens. In an exemplary embodiment, the image side surface of the first lens may be concave.

[0044] In an exemplary embodiment, the second lens may have negative power, and its object side surface may be convex, and its image side surface may be concave. In this embodiment, the third lens may have positive power, and the second lens with negative power and the third lens with positive power may form a cemented lens group by positive and negative combination, which is beneficial for correcting chromatic aberration.

[0045] In an exemplary embodiment, the third lens may have positive power, and its object side surface may be convex. The third lens has positive power, which is beneficial to compressing the light collected by the front optical system of the imaging lens and making the light smoothly transition to the rear optical system, thereby reducing the system sensitivity and increasing the aperture. In an exemplary embodiment, the image side surface of the third lens may be concave or convex.

[0046] In an exemplary embodiment, the ninth lens may have negative power, and its object side surface may be concave, and its image side surface may be concave. In this embodiment, the second lens may have negative power, and the third lens may have positive power, so that the second lens, the third lens and the ninth lens with negative power cooperate to form a triple cemented lens group, which is conducive to compensating the aberration generated by the front lens group and improving the image quality.

[0047] In an exemplary embodiment, the fourth lens may have negative power, and its object side surface may be convex, and its image side surface may be concave. In this embodiment, the fifth lens may have positive power, and the sixth lens may have negative power, so that the fifth lens, the sixth lens and the fourth lens with negative power cooperate to form a triplet lens group, which is beneficial to correct chromatic aberration and improve image quality, and at the same time can effectively and smoothly raise the light, thereby reducing the tolerance sensitivity of the system, which is beneficial to improve the lens assembly yield.

[0048] In an exemplary embodiment, the fifth lens may have positive power, and its object side surface may be convex, and its image side surface may be convex. In this embodiment, the sixth lens may have negative power, and the fourth lens may have negative power, so that the fourth lens, the sixth lens and the fifth lens with positive power cooperate to form a triplet lens group, which is beneficial to correct chromatic aberration and improve image quality, and at the same time can effectively and smoothly raise the light, thereby reducing the tolerance sensitivity of the system, which is beneficial to improve the lens assembly yield.

[0049] In an exemplary embodiment, the sixth lens may have negative power, and its object side surface may be concave, and its image side surface may be concave. In this embodiment, the fourth lens may have negative power, and the fifth lens may have positive power, so that the fourth lens, the fifth lens and the sixth lens with negative power cooperate to form a triplet lens group, which is beneficial to correct chromatic aberration and improve image quality, and at the same time can effectively and smoothly raise the light, thereby reducing the tolerance sensitivity of the system, which is beneficial to improve the lens assembly yield.

[0050] In an exemplary embodiment, the seventh lens may have positive power, and its object side surface may be convex. The seventh lens has positive power, and its object side surface is convex, which is conducive to correcting chromatic aberration and residual aberration, and can effectively control the trend of light, lift the light, and increase the height of the imaging surface. In an exemplary embodiment, the image side surface of the seventh lens may be a plane or a concave surface.

[0051] In an exemplary embodiment, the eighth lens may have negative power, and its image side surface may be concave. The eighth lens has negative power and its image side surface is concave, which is conducive to correcting residual aberrations, and can effectively control the trend of light, lift the light, make the light better match the height of the imaging surface, and further improve the relative illumination.

[0052] In the present application, since the curvature radii of 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 are relatively large, the above-mentioned side surfaces can be convex, flat, or concave, and are variable, and the lens surface shape can be set as needed.

[0053] The imaging lens provided in the embodiments of the present application can achieve low distortion (optical distortion DIS ≤ 0.2%) by making the first lens have positive optical power, the second lens have negative optical power, the third lens have positive optical power, the fourth lens have negative optical power, the fifth lens have positive optical power, the sixth lens have negative optical power, the seventh lens have positive optical power, and the eighth lens have negative optical power.

[0054] In an exemplary embodiment, the imaging lens may further include a stop. The stop may be located on the object side of the first lens, thereby effectively reducing the front aperture and light aberration of the imaging lens.

[0055] In an exemplary embodiment, the imaging lens may further include a filter for correcting color deviation.

[0056] In an exemplary embodiment, the total effective focal length f of the imaging lens may satisfy: f≥190 mm. Further, f may be 198-200 mm, thereby achieving the telephoto requirement for the imaging lens.

[0057] In an exemplary embodiment, any one of the first to ninth lenses may be a glass lens or a plastic lens. The glass lens can effectively suppress the deviation of the back focal length of the imaging lens caused by temperature changes, and improve the stability of the imaging lens; at the same time, the glass lens can effectively avoid the problem of imaging blur caused by high temperature or low temperature environment, ensure the normal use of the imaging lens, and is conducive to realizing the athermalization of the imaging lens, and better corrects the system chromatic aberration, and improves the resolution capability of the imaging lens. The plastic lens can effectively reduce the cost of the imaging lens. As an example, any one of the first to ninth lenses is a glass lens, which is conducive to improving the imaging quality and reliability of the imaging lens; for example, when the first to ninth lenses are all glass lenses, the operating temperature range of the imaging lens is relatively wide, and stable optical performance can be maintained in the range of -30°C to 75°C. As an example, some of the lenses from the first to ninth lenses are glass lenses, and the remaining lenses are plastic lenses. The imaging lens adopts a glass-plastic hybrid form, which can effectively reduce the cost of the imaging lens.

[0058] In an exemplary embodiment, the imaging lens may 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 conditional formula and controlling the ratio range of the effective focal length of the first lens to the total effective focal length, the overall aperture of the imaging lens can be reduced, and the aberration caused by light entering the optical system can be reduced. Preferably, the imaging lens may further satisfy: 1.15≤f1 / f≤1.7, which is more conducive to reducing the aberration of the imaging lens and reducing the size of the lens and the front end of the lens.

[0059] In an exemplary embodiment, the imaging lens may satisfy: 0.6≤fⅡ / f≤0.75, wherein fⅡ 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 conditional formula and controlling the ratio range of the effective focal length of the second lens group to the total effective focal length, the trend of light can be effectively controlled, and the height of the outgoing light can be lowered, which is beneficial to reduce the chromatic aberration of the optical system, improve the resolution of the lens, and reduce the total optical length of the imaging lens. Preferably, the imaging lens may further satisfy: 0.65≤fⅡ / f≤0.7, which is more beneficial to achieve the reduction of aberration, high resolution, and reduction of the total optical length of the imaging lens.

[0060] In an exemplary embodiment, the imaging lens may satisfy: -0.9≤fⅢ / f≤-0.5, wherein fⅢ 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 conditional formula, the ratio range of the effective focal length of the third lens group to the total effective focal length is controlled, which is beneficial to correcting chromatic aberration and improving image quality. At the same time, it can effectively and smoothly raise the light, reduce the tolerance sensitivity of the system, and help to improve the assembly yield of the imaging lens. Preferably, the imaging lens may further satisfy: -0.85≤fⅢ / f≤-0.6, which is more conducive to reducing aberrations, high resolution, and reducing the total optical length of the imaging lens.

[0061] In an exemplary embodiment, the imaging lens can satisfy: -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. By making the imaging lens satisfy the above conditional formula, controlling the ratio range of the effective focal length of the fourth lens group to the total effective focal length is beneficial to correcting the residual aberrations and improving the resolution quality. At the same time, it can also effectively control the trend of light, lift the light, and make the light better match the image plane height, and further increase the focal length of the system and improve the relative illumination. Preferably, the imaging lens can further satisfy: -0.7≤fⅣ / f≤-0.55, which is more conducive to achieving the reduction of aberrations, high resolution, and improved focal length of the imaging lens.

[0062] In an exemplary embodiment, the imaging lens may satisfy: -6≤fII / (Vd2-Vd3)≤-5, wherein 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. By making the imaging lens satisfy the above conditional formula, reasonably selecting the lens materials of the second lens and the third lens, and reasonably configuring 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, the system chromatic aberration can be effectively corrected and the resolution of the imaging lens can be improved. Preferably, the imaging lens may further satisfy: -5.55≤fII / (Vd2-Vd3)≤-5.4, which is more conducive to achieving the correction of chromatic aberration and high resolution of the imaging lens.

[0063] In an exemplary embodiment, the imaging lens may satisfy: 0.6≤(f4-f5) / fⅢ≤1.2, wherein 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, and f5 is the effective focal length of the fifth lens. By making the imaging lens satisfy the above conditional formula, the difference between the effective focal length of the fourth lens and the effective focal length of the fifth lens and the ratio between the effective focal length of the third lens group are reasonably configured, which is conducive to reducing the aberration of the optical system and improving the resolution of the imaging lens. Preferably, the imaging lens may further satisfy: 0.8≤(f4-f5) / fⅢ≤1, which is more conducive to achieving the correction of chromatic aberration and high resolution of the imaging lens.

[0064] In an exemplary embodiment, the imaging lens may satisfy: -1.65≤fⅣ / (f7-f8)≤-1.4, wherein fⅣ is the effective focal length of the fourth lens group, 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 conditional formula and rationally configuring the effective focal lengths of the seventh lens and the eighth lens in the fourth lens group, it is beneficial to reduce the aberration and tolerance sensitivity of the optical system, improve the resolution of the imaging lens, and at the same time, make the light better match the height of the imaging surface, ensure that the height requirements of the image side can be achieved, and further improve the relative illumination of the imaging lens. Preferably, the imaging lens may further satisfy: -1.6≤fⅣ / (f7-f8) / fⅣ≤-1.4, which is more conducive to achieving the correction of chromatic aberration and high resolution of the imaging lens.

[0065] In an exemplary embodiment, the imaging lens may satisfy: 0.3≤BFL / f≤0.35, where f is the total effective focal length of the imaging lens, and BFL is the back focus length of the imaging lens. By making the imaging lens satisfy the above conditional formula, the length of the optical back focus of the imaging lens is controlled, so that the back focus 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 and avoiding mutual interference between components, thereby improving the assembly yield of the imaging lens, and further compensating for high and low temperatures. Preferably, the imaging lens may further satisfy: 0.3≤BFL / f≤0.32, which is more conducive to increasing the back focus of the imaging lens and compensating for high and low temperatures.

[0066] In an exemplary embodiment, the imaging lens may 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 conditional formula and controlling the ratio of the optical back focal length to the total optical length of the imaging lens, the total optical length of the imaging lens can be further constrained while satisfying the imaging requirements of the imaging lens, thereby achieving miniaturization of the imaging lens. Preferably, the imaging lens may further satisfy: 0.4≤BFL / TTL≤0.42, which is more conducive to miniaturization of the overall structure of the imaging lens.

[0067] In an exemplary embodiment, the imaging lens may satisfy: 0.3≤Dmax / TTL≤0.55, where TTL is the total optical length of the imaging lens, and Dmax is the maximum full aperture of the lens in the imaging lens. By making the imaging lens satisfy the above conditional formula, the maximum aperture and the total optical length of the front end of the imaging lens are reasonably constrained, which is conducive to reducing the overall size of the imaging lens, making the entire imaging lens more compact, so as to achieve miniaturization. Preferably, the imaging lens may further satisfy: 0.4≤Dmax / TTL≤0.5, which is more conducive to achieving miniaturization of the size of the imaging lens.

[0068] In an exemplary embodiment, the imaging lens may 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 conditional formula and by reasonably adjusting the total optical length of the imaging lens and the effective focal length of the system, it is beneficial to make the entire imaging lens more compact so as to achieve miniaturization. Preferably, the imaging lens may further satisfy: 1.3≤f / TTL≤1.35, which is more conducive to achieving miniaturization of the size of the imaging lens.

[0069] In an exemplary embodiment, the imaging lens may satisfy: 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 making the imaging lens satisfy the above conditional formula, the size of the entrance pupil diameter of the imaging lens is reasonably controlled, which is conducive to increasing the aperture and improving the illumination of the imaging lens. Preferably, the imaging lens may further satisfy: 2.8≤f / EPD≤3.1, which is more conducive to realizing the limited aperture of the imaging lens.

[0070] In an exemplary embodiment, the imaging lens may satisfy: 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. By making the imaging lens satisfy the above conditional formula, reasonably selecting the lens material of the fifth lens, and reasonably configuring the ratio of the Abbe number of the fifth lens to its effective focal length, the system chromatic aberration can be effectively corrected and the resolution of the imaging lens can be improved. Preferably, the imaging lens may further satisfy: 1.35≤Vd5 / f5≤1.5, which is more conducive to achieving the correction of chromatic aberration and high resolution of the imaging lens.

[0071] The imaging lens according to the above-mentioned embodiment of the present application can adopt multiple lenses, for example, the nine lenses mentioned above. By reasonably allocating the optical parameters such as the optical focal length and surface shape of each lens, it can 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), high and low temperature resistance (can work continuously for a long time under high and low temperature conditions of -30 to + 70°C).

[0072] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the imaging lens can be changed to obtain the various results and advantages described in this specification.

[0073] Specific embodiments of the imaging lens applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings.

[0074] Example 1

[0075] 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 Embodiment 1 of the present application.

[0076] like Figure 1 As shown, the imaging lens includes 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 in order from the object side to the image side along the optical axis. The aperture STO is arranged 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.

[0077] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is concave.

[0078] The second lens L2 has negative refractive power, and its object-side surface S3 is convex, and its image-side surface S4 is concave.

[0079] The third lens L3 has positive refractive power, an object-side surface S4 thereof is convex, and an image-side surface S5 thereof is concave.

[0080] The fourth lens L4 has negative refractive power, and its object-side surface S6 is convex, and its image-side surface S7 is concave.

[0081] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex, and its image-side surface S8 is convex.

[0082] The sixth lens L6 has negative refractive power, and its object-side surface S8 is concave, and its image-side surface S9 is concave.

[0083] The seventh lens L7 has positive refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is flat or concave.

[0084] The eighth lens L8 has negative refractive power, and its object-side surface S11 is a flat or convex surface, and its image-side surface S12 is a concave surface.

[0085] In this embodiment, since the curvature radii 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 relatively large, the above-mentioned side surfaces can be convex, flat, or concave, which are variable and can be set according to actual needs.

[0086] 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 .

[0087] The light from the object passes through the surfaces S1-S14 in sequence and is finally imaged on the imaging surface IMA. Figure 1 Not shown.

[0088] Table 1 shows the basic parameters of the imaging lens of Example 1, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0089]

[0090]

[0091] Table 1

[0092] In this embodiment, the aperture number Fno of the imaging lens is set to 3. The image height corresponding to the maximum field angle of the imaging lens is 7.88 mm, and the relative illumination is 99.15%.

[0093] Figure 2 The distortion curve of the imaging lens of Example 1 is shown in FIG. Figure 2 As shown, the maximum optical distortion DIS of the imaging lens of Example 1 is 0.18%. Therefore, the imaging lens provided in Example 1 can achieve good imaging quality.

[0094] Example 2

[0095] The following reference Figure 3 An imaging lens according to Embodiment 2 of the present application is described. Figure 3 Schematic diagram of the structure of an imaging lens according to Embodiment 2 of the present application.

[0096] like Figure 3As shown, the imaging lens includes 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 in order from the object side to the image side along the optical axis. The aperture STO is arranged 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.

[0097] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is concave.

[0098] The second lens L2 has negative refractive power, and its object-side surface S3 is convex, and its image-side surface S4 is concave.

[0099] The third lens L3 has positive refractive power, an object-side surface S4 thereof is convex, and an image-side surface S5 thereof is concave.

[0100] The fourth lens L4 has negative refractive power, and its object-side surface S6 is convex, and its image-side surface S7 is concave.

[0101] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex, and its image-side surface S8 is convex.

[0102] The sixth lens L6 has negative refractive power, and its object-side surface S8 is concave, and its image-side surface S9 is concave.

[0103] The seventh lens L7 has positive refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is flat or concave.

[0104] The eighth lens L8 has negative refractive power, and its object-side surface S11 is a flat or convex surface, and its image-side surface S12 is a concave surface.

[0105] In this embodiment, since the curvature radii 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 relatively large, the above-mentioned side surfaces can be convex, flat, or concave, which are variable and can be set according to actual needs.

[0106] 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 .

[0107] The light from the object passes through the surfaces S1-S14 in sequence and is finally imaged on the imaging surface IMA. Figure 1 Not shown.

[0108] Table 2 shows the basic parameters of the imaging lens of Example 2, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0109]

[0110] Table 2

[0111] In this embodiment, the aperture number Fno of the imaging lens is set to 2.8. The image height corresponding to the maximum field angle of the imaging lens is 7.88 mm, and the relative illumination is 99.18%.

[0112] Figure 4 The distortion curve of the imaging lens of Example 2 is shown as follows: Figure 4 As shown, the maximum optical distortion DIS of the imaging lens of Example 2 is 0.17%. Therefore, the imaging lens provided in Example 2 can achieve good imaging quality.

[0113] Example 3

[0114] The following reference Figure 5 An imaging lens according to Embodiment 3 of the present application is described. Figure 5 Schematic diagram of the structure of an imaging lens according to Embodiment 3 of the present application.

[0115] like Figure 5 As shown, the imaging lens includes 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 in order from the object side to the image side along the optical axis. The aperture STO is arranged 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.

[0116] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is concave.

[0117] The second lens L2 has negative refractive power, and its object-side surface S3 is convex, and its image-side surface S4 is concave.

[0118] The third lens L3 has positive refractive power, and its object-side surface S4 is convex and its image-side surface S5 is convex.

[0119] The ninth lens L9 has negative refractive power, and its object-side surface S5 is concave, and its image-side surface S6 is concave.

[0120] The fourth lens L4 has negative refractive power, and its object-side surface S7 is convex, and its image-side surface S8 is concave.

[0121] The fifth lens L5 has positive refractive power, and its object-side surface S8 is convex and its image-side surface S9 is convex.

[0122] The sixth lens L6 has negative refractive power, and its object-side surface S9 is concave and its image-side surface S10 is concave.

[0123] The seventh lens L7 has positive refractive power, and its object-side surface S11 is convex, and its image-side surface S12 is flat or concave.

[0124] The eighth lens L8 has negative refractive power, and its object-side surface S12 is a flat or convex surface, and its image-side surface S13 is a concave surface.

[0125] In this embodiment, since the curvature radii of 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 are relatively large, the above-mentioned side surfaces can be convex, flat, or concave, which are variable and can be set according to actual needs.

[0126] 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 .

[0127] The light from the object passes through the surfaces S1-S15 in sequence and is finally imaged on the imaging surface IMA. Figure 5 Not shown.

[0128] Table 3 shows the basic parameters of the imaging lens of Example 3, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0129]

[0130] Table 3

[0131] In this embodiment, the aperture number Fno of the imaging lens is set to 2.9. The image height corresponding to the maximum field angle of the imaging lens is 7.88 mm, and the relative illumination is 99.21%.

[0132] Figure 6 The distortion curve of the imaging lens of Example 3 is shown as follows: Figure 6 As shown, the maximum optical distortion DIS of the imaging lens of Example 3 is 0.17%. Therefore, the imaging lens provided in Example 3 can achieve good imaging quality.

[0133] Example 4

[0134] The following reference Figure 7 An imaging lens according to Embodiment 4 of the present application is described. Figure 7 Schematic diagram of the structure of an imaging lens according to Embodiment 4 of the present application.

[0135] like Figure 7As shown, the imaging lens includes 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 in order from the object side to the image side along the optical axis. The aperture STO is arranged 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.

[0136] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is concave.

[0137] The second lens L2 has negative refractive power, and its object-side surface S3 is convex, and its image-side surface S4 is concave.

[0138] The third lens L3 has positive refractive power, and its object-side surface S4 is convex and its image-side surface S5 is convex.

[0139] The ninth lens L9 has negative refractive power, and its object-side surface S5 is concave, and its image-side surface S6 is concave.

[0140] The fourth lens L4 has negative refractive power, and its object-side surface S7 is convex, and its image-side surface S8 is concave.

[0141] The fifth lens L5 has positive refractive power, and its object-side surface S8 is convex and its image-side surface S9 is convex.

[0142] The sixth lens L6 has negative refractive power, and its object-side surface S9 is concave and its image-side surface S10 is concave.

[0143] The seventh lens L7 has positive refractive power, and its object-side surface S11 is convex, and its image-side surface S12 is flat or concave.

[0144] The eighth lens L8 has negative refractive power, and its object-side surface S12 is a flat or convex surface, and its image-side surface S13 is a concave surface.

[0145] In this embodiment, since the curvature radii of 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 are relatively large, the above-mentioned side surfaces can be convex, flat, or concave, which are variable and can be set according to actual needs.

[0146] 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 .

[0147] The light from the object passes through the surfaces S1-S15 in sequence and is finally imaged on the imaging surface IMA. Figure 7 Not shown.

[0148] Table 4 shows the basic parameter table of the imaging lens of Example 4, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0149]

[0150]

[0151] Table 4

[0152] In this embodiment, the aperture number Fno of the imaging lens is set to 3.1. The image height corresponding to the maximum field angle of the imaging lens is 7.88 mm, and the relative illumination is 99.23%.

[0153] Figure 8 The distortion curve of the imaging lens of Example 4 is shown as follows: Figure 8 As shown, the maximum optical distortion DIS of the imaging lens of Example 4 is 0.16%. Therefore, the imaging lens provided in Example 4 can achieve good imaging quality.

[0154] In summary, the conditional expressions in Examples 1 to 4 satisfy the relationship shown in Table 5. In Table 5, the units of f, EPD, TTL, BFL, f1, f4, f5, f7, f8, fII to fIV, and Dmax are millimeters (mm).

[0155]

[0156] Table 6

[0157] The present application also provides an imaging device, whose electronic photosensitive element may be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and the imaging device is equipped with the imaging lens described above.

[0158] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

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; a second lens having negative optical power; a third lens having positive refractive power; a fourth lens having negative optical power; a fifth lens having positive refractive power; a sixth lens having negative optical power; a seventh lens having positive refractive power; and an eighth lens having negative optical power; The number of lenses having optical power of 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, characterized in that: 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 1, wherein: The object side surface of the first lens is a convex surface; The image side surface of the eighth lens is a concave surface.

4. The imaging lens according to claim 2, wherein: The second lens, the third lens and the ninth lens are cemented together to form a second lens group.

5. The imaging lens according to claim 1, wherein: The second lens and the third lens are cemented together to form a second lens group.

6. The imaging lens according to claim 1, wherein: The seventh lens and the eighth lens are cemented together to form a fourth lens group.

7. The imaging lens according to claim 1, wherein: The fourth lens, the fifth lens and the sixth lens are cemented together to form a third lens group.

8. 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 of the sixth lens is concave, and the image side surface is concave; and The object side surface of the seventh lens is a convex surface.

9. The imaging lens according to any one of claims 1 to 8, characterized in that: The imaging lens satisfies: 1.1≤f1 / f≤1.8, Wherein, f is the total effective focal length of the imaging lens, and f1 is the effective focal length of the first lens.

10. The imaging lens according to claim 4 or 5, characterized in that: The imaging lens meets the following requirements: 0.6≤fⅡ / f≤0.75, Among them, fⅡ is the effective focal length of the second lens group, and f is the total effective focal length of the imaging lens.

Images