Imaging lens

Abstract

This invention relates to an imaging lens, comprising, along the optical axis from the object side to the image side, the following components in sequence: a first lens group with positive optical power, a second lens group with negative optical power, and a third lens group with positive optical power. The first and third lens groups are fixed lens groups, and the second lens group is a focusing group. The first lens group includes a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, and a fourth lens with negative optical power. The second lens group includes a fifth lens with positive optical power and a sixth lens with negative optical power. The third lens group includes a seventh and an eighth lens with opposite optical power and a ninth lens with positive optical power. The effective focal length FG2 of the second lens group and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy: -2.4 ≤ FG2 / FI ≤ -0.3. The imaging lens of this invention possesses at least one of the following characteristics: wide object distance, low distortion, high illumination, no defocusing at high temperatures, and no thermalization.

Description

Technical Field

[0001] This invention relates to the field of industrial lens technology, and in particular to an imaging lens with wide object distance, low distortion, high illumination, no defocusing at high temperatures, and no thermalization. Background Technology

[0002] Industrial lenses are an indispensable component of machine vision systems, playing a crucial role in applications such as automated inspection, quality control, measurement, and identification.

[0003] Industrial lenses currently on the market still have the following shortcomings:

[0004] 1. Existing lenses have a narrow focusing distance range, which does not meet the requirements for use in multiple scenarios;

[0005] 2. The existing lens has significant distortion, resulting in a large degree of image distortion;

[0006] 3. The existing lens has low illumination, resulting in a dark image and low color saturation;

[0007] 4. Existing lenses produce low image clarity when capturing objects at a distance;

[0008] 5. Existing lenses experience focus drift in high and low temperature environments, severely impacting image quality.

[0009] Therefore, designing an imaging lens that meets at least one of the following characteristics—wide focusing distance range, low distortion, high illumination, no defocusing at high temperatures, and no thermalization—has become a market trend. Summary of the Invention

[0010] To address the problems existing in the prior art, the present invention aims to provide an imaging lens that has at least one of the following characteristics: wide object distance, low distortion, high illumination, no defocusing at high temperatures, and no thermalization.

[0011] To achieve the above-mentioned objective, the present invention provides an imaging lens, which, along the optical axis from the object side to the image side, sequentially includes: a first lens group with positive optical power, a second lens group with negative optical power, and a third lens group with positive optical power. The first lens group and the third lens group are fixed lens groups, and the second lens group is a focusing group that moves along the optical axis of the imaging lens.

[0012] The first lens group includes, in sequence, a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, and a fourth lens with negative optical power, for a total of four lenses;

[0013] The second lens group includes, in sequence, a fifth lens with positive optical power and a sixth lens with negative optical power, for a total of two lenses;

[0014] The third lens group includes, in sequence, a seventh lens, an eighth lens, and a ninth lens with positive optical power, for a total of three lenses; the seventh lens and the eighth lens have opposite optical powers.

[0015] According to one technical solution of the present invention, the object-side surface of the first lens is convex, the image-side surface of the second lens is concave, the third lens is a convex-convex lens, and the object-side surface of the fourth lens is concave.

[0016] According to one technical solution of the present invention, the image-side surface of the fifth lens is convex; the sixth lens is a concave-concave lens.

[0017] According to one technical solution of the present invention, the object-side surface of the ninth lens is convex.

[0018] According to one technical solution of the present invention, the third lens and the fourth lens form a cemented doublet lens, and the fifth lens and the sixth lens form a cemented doublet lens.

[0019] According to one technical solution of the present invention, the effective focal length FG1 of the first lens group and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.8≤FG1 / FI≤1.7.

[0020] According to one technical solution of the present invention, the effective focal length FG3 of the third lens group and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.5≤FG3 / FI≤1.1.

[0021] According to one technical solution of the present invention, the focusing movement distance d2 of the second lens group within the object distance variation range and the effective focal length FG2 of the second lens group satisfy the following relationship: -5.6≤FG2 / d2≤-3.6.

[0022] According to one technical solution of the present invention, the air gap distance d23 between the second lens and the third lens on the optical axis and the effective focal length FG1 of the first lens group satisfy the following relationship: 2.5≤FG1 / d23≤120.

[0023] According to one technical solution of the present invention, the air gap distance d23 between the second lens and the third lens on the optical axis satisfies the following relationship with the effective focal length FG1 of the first lens group: 2.5≤FG1 / d23≤9.

[0024] According to one technical solution of the present invention, the combined effective focal length F34 of the third lens and the fourth lens satisfies the following relationship with the effective focal length FG1 of the first lens group: 0.2≤F34 / FG1≤1.1.

[0025] According to one technical solution of the present invention, the effective focal length F1 of the first lens and the effective focal length FG1 of the first lens group satisfy the following relationship: 0.95≤FG1 / F1≤1.7.

[0026] According to one technical solution of the present invention, the effective focal length FG1 of the first lens group and the effective focal length F2 of the second lens satisfy the following relationship: -2.85≤FG1 / F2≤-1.

[0027] According to one technical solution of the present invention, the effective focal length F4 of the fourth lens and the effective focal length F3 of the third lens satisfy the following relationship: -3.4≤F4 / F3≤-1.6.

[0028] According to one technical solution of the present invention, the Abbe number Vd3 of the third lens and the effective focal length F3 of the third lens satisfy the following relationship: 2.4≤Vd3 / F3≤4.

[0029] According to one technical solution of the present invention, the effective focal length F5 of the fifth lens and the effective focal length F6 of the sixth lens satisfy the following relationship: -2.8≤F5 / F6≤-1.3.

[0030] According to one technical solution of the present invention, the effective focal length FG3 of the third lens group, the effective focal length F7 of the seventh lens, the effective focal length F8 of the eighth lens, and the effective focal length F9 of the ninth lens satisfy the following relationship: 0.8≤FG3 / (F7+F8+F9)≤1.9.

[0031] According to one technical solution of the present invention, the maximum effective aperture of the lens DG1_MAX of the first lens to the ninth lens and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 4.87≤FI / DG1_MAX≤5.6.

[0032] According to one technical solution of the present invention, the maximum effective aperture DG1_MAX of the lens in the first lens to the ninth lens and the total optical system length TTL of the imaging lens satisfy the following relationship: 9≤TTL / DG1_MAX≤10.4.

[0033] According to one technical solution of the present invention, the back focal length BFL of the imaging lens and the total optical system length TTL of the imaging lens satisfy the following relationship: 0.3≤BFL / TTL≤0.5.

[0034] According to one technical solution of the present invention, the total optical system length TTL of the imaging lens and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 1.6≤TTL / FI≤2.

[0035] According to one technical solution of the present invention, the Abbe number Vd6 of the sixth lens, the Abbe number Vd5 of the fifth lens, and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.15≤(Vd6-Vd5) / FI≤0.75.

[0036] According to one technical solution of the present invention, the total effective focal length FI of the imaging lens at an object distance of 0.3m and the effective focal length FII of the imaging lens at an object distance of infinity satisfy the following relationship: 1≤FI / FII≤1.5.

[0037] According to one technical solution of the present invention, the effective focal length FG2 of the second lens group and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: -2.4≤FG2 / FI≤-0.3.

[0038] According to one technical solution of the present invention, the imaging lens satisfies at least one of the following conditions:

[0039] 0.88≤FG1 / FI≤1.63

[0040] -2.2≤FG2 / FI≤-0.5,

[0041] 0.95≤FG3 / FI≤0.65

[0042] -5.4≤FG2 / d2≤-3.9,

[0043] 2.6≤FG1 / d23≤8.55,

[0044] 0.2≤F34 / FG1≤1.05,

[0045] 1≤FG1 / F1≤1.6,

[0046] -2.7≤FG1 / F2≤-1.2,

[0047] -3.2≤F4 / F3≤-1.8,

[0048] 2.55≤Vd3 / F3≤3.85,

[0049] -2.65≤F5 / F6≤-1.5,

[0050] 1.0≤FG3 / (F7+F8+F9)≤1.85,

[0051] 4.9≤FI / DG1_MAX≤5.5

[0052] 9.2≤TTL / DG1_MAX≤10.3

[0053] 0.3≤BFL / TTL≤0.4

[0054] 1.7≤TTL / FI≤2

[0055] 0.2≤(Vd6-Vd5) / FI≤0.7,

[0056] 1≤FI / FII≤1.25,

[0057] Wherein, FI is the total effective focal length of the imaging lens at an object distance of 0.3m, FG1 is the effective focal length of the first lens group, FG2 is the effective focal length of the second lens group, FG3 is the effective focal length of the third lens group, d2 is the focusing distance of the second lens group within the range of object distance variation, d23 is the air gap distance between the second lens and the third lens on the optical axis, F34 is the combined effective focal length of the third lens and the fourth lens, F1 is the effective focal length of the first lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, and F4 is the effective focal length of the fourth lens. The effective focal length of the lens, Vd3 is the Abbe number of the third lens, F5 is the effective focal length of the fifth lens, F6 is the effective focal length of the sixth lens, F7 is the effective focal length of the seventh lens, F8 is the effective focal length of the eighth lens, F9 is the effective focal length of the ninth lens, DG1_MAX is the maximum effective aperture of the lens from the first lens to the ninth lens, TTL is the total length of the optical system of the imaging lens, BFL is the back focal length of the imaging lens, Vd6 is the Abbe number of the sixth lens, Vd5 is the Abbe number of the fifth lens, and FII is the effective focal length of the imaging lens when the object distance is infinity.

[0058] According to the present invention, by setting the number and optical power of the imaging lenses, the ultra-wide-angle lens achieves at least one of the following beneficial effects: wide working distance (clear focus at object distances from 0.3m to infinity), low distortion (absolute optical distortion ≤ 0.75%), high illumination (relative illumination RI ≥ 70%), and miniaturization (total optical length TTL ≤ 79mm); the aperture is rear-mounted and the aperture is constant (FNO = 3.0); the problem of focus drift in high and low temperature environments is solved, and the lens can remain in focus within a temperature range of -40℃ to 80℃, achieving lens heat-free operation and making it suitable for various high and low temperature environments. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0060] Figure 1 This is a schematic diagram of the imaging lens in Embodiment 1 of the present invention;

[0061] Figure 2 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 1 of the present invention is 0.3m;

[0062] Figure 3 This is a schematic diagram of the distortion of the imaging lens in Embodiment 1 of the present invention when the object distance is infinity;

[0063] Figure 4 This is a schematic diagram of the imaging lens in Embodiment 2 of the present invention;

[0064] Figure 5 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 2 of the present invention is 0.3m;

[0065] Figure 6 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 2 of the present invention is infinity;

[0066] Figure 7 This is a schematic diagram of the imaging lens in Embodiment 3 of the present invention;

[0067] Figure 8 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 3 of the present invention is 0.3m;

[0068] Figure 9 This is a schematic diagram of the distortion of the imaging lens in Embodiment 3 of the present invention when the object distance is infinity.

[0069] Figure 10 This is a schematic diagram of the imaging lens in Embodiment 4 of the present invention;

[0070] Figure 11 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 4 of the present invention is 0.3m;

[0071] Figure 12 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 4 of the present invention is infinity;

[0072] Figure 13 This is a schematic diagram of the imaging lens in Embodiment 5 of the present invention;

[0073] Figure 14 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 5 of the present invention is 0.3m;

[0074] Figure 15 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 5 of the present invention is infinity. Detailed Implementation

[0075] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0076] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the first lens.

[0077] In the accompanying 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 illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0078] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity 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 location of the concaveness 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 subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0079] It should also be understood that the terms "comprising," "including," "having," "containing," 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. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0080] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0081] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application.

[0082] like Figures 1 to 15 As shown, an embodiment of the present invention provides an imaging lens, which, along the optical axis from the object side to the image side, sequentially includes: a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, an aperture stop STO, a parallel plate CG, and an image plane IMA. The first lens group G1 and the third lens group are fixed lens groups, and the second lens group G2 is a focusing group that moves along the optical axis of the imaging lens.

[0083] Among them, the first lens group G1 is a fixed front group and has positive optical power, which is conducive to converging the incident light into the optical system, effectively controlling the direction of the light, balancing the spherical aberration and coma generated by the optical system, compensating for the system chromatic aberration, and ensuring the resolution quality of the lens; at the same time, it effectively reduces the tolerance sensitivity of the optical system and improves the lens production yield.

[0084] The second lens group G2 is a focusing group, and the second lens group G2 has negative optical power. It moves along the optical axis from the image side to the object side. By changing the position of the second lens group on the optical axis, the working distance of the lens can be supported from 0.3M to infinity, which meets the requirements of a wide range of working distances.

[0085] The third lens group G3 is a fixed rear group and has positive optical power. Its position relative to the image plane is fixed, which effectively controls the direction of light and allows the light to transition smoothly onto the image plane. This corrects the astigmatism and field curvature of the optical system, reduces the tolerance sensitivity of the optical system, helps to ensure the resolution quality of the lens, and improves the production yield. At the same time, it can also effectively compensate for the on-axis chromatic aberration of the optical system and ensure the color reproduction of the image.

[0086] In this embodiment of the invention, along the optical axis from the object side to the image side, the first lens group G1 sequentially includes: a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4, for a total of four lenses.

[0087] The object side of the first lens L1 is convex and has positive optical power, which is beneficial for converging incident light rays into the optical system.

[0088] The image side of the second lens L2 is concave and has negative optical power, which helps the light to diverge after passing through the second lens L2, effectively controlling the direction of the light and allowing the light direction to better cooperate with the large-diameter third lens L3 and fourth lens L4; at the same time, it also helps to reduce the distortion of the optical system, so that the absolute value of the optical distortion of the lens is ≤0.75%.

[0089] The third lens L3 is a convex-convex lens with positive optical power, while the fourth lens L4 has a concave object-side surface and negative optical power. The combination of positive and negative optical powers in the third lens L3 and the fourth lens L4, along with their relatively large apertures, facilitates chromatic aberration correction in the optical system and improves the imaging performance of the telephoto lens. The third lens L3 and the fourth lens L4 can be used together to form a cemented lens. When forming a cemented doublet, this effectively reduces the tolerance sensitivity of the optical system and improves the lens's production yield.

[0090] In this embodiment of the invention, along the optical axis from the object side to the image side, the second lens group G2 sequentially includes a fifth lens L5 and a sixth lens L6, for a total of two lenses.

[0091] The fifth lens, L5, has a convex image-side surface and positive optical power; the sixth lens, L6, is a concave lens with negative optical power. The fifth lens L5 and the sixth lens L6 combine positive and negative optical power elements. Furthermore, the fifth lens L5 can be made of a high-dispersion material, while the sixth lens L6 can be made of a low-dispersion material. Using materials with different dispersion coefficients allows for mutual compensation of dispersion, eliminating positional chromatic aberration and improving the imaging performance of telephoto lenses. The fifth lens L5 and the sixth lens L6 can be used together to form a cemented doublet lens group. When forming a cemented doublet lens, the tolerance sensitivity of the optical system can be effectively reduced, improving the lens's production yield.

[0092] The third lens group G3 consists of three lenses: the seventh lens L7, the eighth lens L8, and the ninth lens L9.

[0093] The seventh lens L7 and the eighth lens L8 have opposite optical powers, while the object side of the ninth lens L9 is convex and has positive optical power. By reasonably setting the optical powers of the seventh lens L7, the eighth lens L8, and the ninth lens L9, and matching their positive-negative-positive or negative-positive-positive optical powers, it is beneficial to compensate for positive and negative spherical aberrations, correct astigmatism and field curvature of the system, and improve lens resolution; at the same time, it effectively controls the direction of light, making the light transition smooth and effectively reducing the tolerance sensitivity of the fixed rear group.

[0094] The seventh lens L7, the eighth lens L8, and the ninth lens L9 can be combined to form a cemented triplet lens, or they can be combined with a single lens and a set of cemented doublet lenses. This can effectively balance axial chromatic aberration, improve the resolution of the lens, and also effectively reduce the tolerance sensitivity of the fixed rear group, thereby improving the production yield.

[0095] This invention employs a constant aperture, which can maintain a constant aperture throughout the object distance range from 0.3m to infinity, thus ensuring that the resolution does not decrease and the image is clear.

[0096] This invention employs a focusing lens architecture with three lens groups (positive, negative, and positive) and an aperture stop, which effectively meets the usage requirements within an object distance range from 0.3m to infinity. It also facilitates the correction of field curvature and distortion, reduces system tolerance sensitivity, eliminates system chromatic aberration, and reduces lens purple fringing. The rational combination of the group optical powers allows light to pass smoothly through the lens, significantly correcting advanced aberrations and improving image quality. Simultaneously, it enables continuous adjustment of the focusing lens group within the 0.3m to infinity object distance range, compensating for aberrations caused during zoom movement and effectively ensuring image clarity at different object distances.

[0097] In some embodiments of the present invention, the first lens L1 to the ninth lens L9 may be made of glass or plastic, and the lens surface may be spherical or aspherical. Optical lenses made of glass can suppress the shift of the back focus of the imaging lens due to temperature changes, thereby improving system stability. Simultaneously, using glass can avoid lens blurring caused by high and low temperature changes in the operating environment, affecting the normal use of the lens and facilitating heatless lens operation. Furthermore, it can better correct system chromatic aberration and improve lens resolution. In some embodiments of the present invention, the first lens L1 to the ninth lens L9 are all made of glass, and the all-glass imaging lens has a wide temperature range, maintaining stable optical performance within the range of -40℃ to 85℃.

[0098] In some embodiments of the present invention, the effective focal length FG1 of the first lens group G1 and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.8≤FG1 / FI≤1.7, preferably, 0.88≤FG1 / FI≤1.63. Reasonably controlling the ratio of the focal length FG1 of the first lens group G1 to the effective focal length FI of the imaging lens at an object distance of 0.3m is beneficial for converging incident light rays into the optical system, effectively controlling the light trajectory, compensating for spherical aberration, coma, and on-axis chromatic aberration of the optical system, and improving the imaging quality of the lens.

[0099] In some embodiments of the present invention, the effective focal length FG2 of the second lens group G2 and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: -2.4≤FG2 / FI≤-0.3, preferably -2.2≤FG2 / FI≤-0.5. By reasonably controlling the ratio of the effective focal length FG2 of the second lens group G2 to the total effective focal length FI of the imaging lens at an object distance of 0.3m, it is beneficial to enable the lens to support a working distance from 0.3m to infinity, thus meeting the requirements of a wide range of working distances.

[0100] In some embodiments of the present invention, the effective focal length FG3 of the third lens group G3 and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.5≤FG3 / FI≤1.1, preferably, 0.95≤FG3 / FI≤0.65. By reasonably controlling the ratio of the effective focal length FG3 of the third lens group G3 to the total effective focal length FI of the imaging lens at an object distance of 0.3m, the trend of light is effectively controlled, allowing the light to transition smoothly onto the image plane, correcting the astigmatism and field curvature of the optical system, reducing the tolerance sensitivity of the optical system, helping to ensure the resolving quality of the lens and improve production yield; at the same time, it can also effectively compensate for the on-axis chromatic aberration of the optical system, ensuring the color reproduction of the image.

[0101] In some embodiments of the present invention, the focusing distance d2 of the second lens group G2 within the object distance variation range and the effective focal length FG2 of the second lens group G2 satisfy the following relationship: -5.6≤FG2 / d2≤-3.6, preferably -5.4≤FG2 / d2≤-3.9. By reasonably controlling the ratio of the effective focal length FG2 of the second lens group G2 to the focusing distance d2 of the second lens group G2 within the object distance variation range, it is beneficial to reasonably control the movement range distance of the second lens group G2 during focusing, so that it meets the working distance requirements over a wide range while effectively limiting the length of the imaging lens, thereby facilitating the miniaturization of the imaging lens and improving the focusing response speed of the lens; it also effectively ensures the tolerance sensitivity of the optical system.

[0102] In some embodiments of the present invention, the air gap distance d23 between the second lens L2 and the third lens L3 on the optical axis satisfies the following relationship with the effective focal length FG1 of the first lens group G1: 2.5 ≤ FG1 / d23 ≤ 120, preferably 2.5 ≤ FG1 / d23 ≤ 9, and further preferably 2.6 ≤ FG1 / d23 ≤ 8.55. By reasonably controlling the air gap distance d23 between the second lens L2 and the third lens L3 on the optical axis in the first lens group G1, the direction of light can be effectively controlled, the deflection angle of light entering the object side of the third lens L3 can be reduced, and the direction of light can better cooperate with the large-aperture third lens L3 and fourth lens L4.

[0103] In some embodiments of the present invention, the combined effective focal length F34 of the third lens L3 and the fourth lens L4 and the effective focal length FG1 of the first lens group G1 satisfy the following relationship: 0.2 ≤ F34 / FG1 ≤ 1.1, preferably, 0.2 ≤ F34 / FG1 ≤ 1.05. By reasonably controlling the ratio of the combined effective focal length F34 of the third lens L3 and the fourth lens L4 to the effective focal length FG1 of the first lens group G1, it is beneficial to correct chromatic aberration in the optical system. At the same time, positive spherical aberration is introduced to compensate for spherical aberration in the optical system, thereby improving the imaging performance of the telephoto lens. It can also effectively reduce thermal residue in the optical system and ensure that the lens is heat-free.

[0104] In some embodiments of the present invention, the effective focal length F1 of the first lens L1 and the effective focal length FG1 of the first lens group G1 satisfy the following relationship: 0.95≤FG1 / F1≤1.7, preferably, 1≤FG1 / F1≤1.6. By reasonably controlling the ratio of the effective focal length FG1 of the first lens group G1 to the effective focal length F1 of the first lens L1, it is beneficial to converge the incident light rays into the optical system, expand the field of view, and make the field of view meet the design requirements.

[0105] In some embodiments of the present invention, the effective focal length FG1 of the first lens group G1 and the effective focal length F2 of the second lens L2 satisfy the following relationship: -2.85≤FG1 / F2≤-1, preferably -2.7≤FG1 / F2≤-1.2. By reasonably controlling the effective focal length FG1 of the first lens group G1 and the effective focal length F2 of the second lens L2, it is beneficial for the light to diverge after passing through the second lens L2, effectively controlling the light path and allowing the light path to better cooperate with the large-aperture third lens L3 and fourth lens L4; at the same time, it is also beneficial to reduce the distortion of the optical system, so that the absolute value of the optical distortion of the lens is ≤0.75%.

[0106] In some embodiments of the present invention, the effective focal length F4 of the fourth lens L4 and the effective focal length F3 of the third lens L3 satisfy the following relationship: -3.4 ≤ F4 / F3 ≤ -1.6, preferably -3.2 ≤ F4 / F3 ≤ -1.8. By setting the two lenses to have a positive and negative optical power combination, the direction of light is effectively controlled, which is beneficial for the light to converge after passing through the third lens L3 and the fourth lens L4. This facilitates chromatic aberration correction in the optical system, improves the imaging performance of the telephoto lens, and effectively reduces the tolerance sensitivity of the optical system, thereby increasing the lens production yield.

[0107] In some embodiments of the present invention, the Abbe number Vd3 of the third lens L3 and the effective focal length F3 of the third lens L3 satisfy the following relationship: 2.4 ≤ Vd3 / F3 ≤ 4, preferably, 2.55 ≤ Vd3 / F3 ≤ 3.85. Reasonably controlling the ratio of the Abbe number Vd3 of the third lens L3 to its effective focal length F3, and using a low-dispersion glass material for the third lens L3, helps to correct chromatic aberration in the system; it also helps to ensure the insensitivity of the optical system within the range of changes in ambient temperature and object distance, effectively reducing residual thermal differences in the optical system, achieving a heat-free lens, and making it suitable for various environments.

[0108] In some embodiments of the present invention, the effective focal length F5 of the fifth lens L5 and the effective focal length F6 of the sixth lens L6 satisfy the following relationship: -2.8 ≤ F5 / F6 ≤ -1.3, preferably -2.65 ≤ F5 / F6 ≤ -1.5. By reasonably controlling the ratio of the effective focal lengths of the fifth lens L5 and the sixth lens L6, and using a combination of positive and negative power lenses, chromatic aberration of the optical system within the range of object distance variation can be effectively corrected, while simultaneously reducing the tolerance sensitivity of the optical system and improving the production yield of the lens.

[0109] In some embodiments of the present invention, the effective focal length FG3 of the third lens group G3 and the effective focal lengths F7 of the seventh lens L7, F8 of the eighth lens L8, and F9 of the ninth lens L9 satisfy the following relationship: 0.8 ≤ FG3 / (F7+F8+F9) ≤ 1.9, preferably, 1.0 ≤ FG3 / (F7+F8+F9) ≤ 1.85. Reasonably setting the optical power of the seventh lens L7, the eighth lens L8, and the ninth lens L9 is beneficial for mutual compensation of positive and negative spherical aberrations, while correcting astigmatism and field curvature of the system, improving lens resolution; at the same time, it effectively controls the light path, making the light transition smooth, effectively reducing the tolerance sensitivity of the fixed rear group, and improving production yield.

[0110] In some embodiments of the present invention, the maximum effective aperture DG1_MAX of the first lens L1 to the ninth lens L9 and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 4.87≤FI / DG1_MAX≤5.6, preferably 4.9≤FI / DG1_MAX≤5.5. Reasonably controlling the ratio of the total effective focal length FI of the imaging lens at an object distance of 0.3m to the maximum effective aperture DG1_MAX of the first lens L1 to the ninth lens L9, and setting a larger aperture, can help improve the chromatic aberration of the optical system and enhance the imaging performance of the lens.

[0111] In some embodiments of the present invention, the maximum effective aperture DG1_MAX of the first lens L1 to the ninth lens L9 and the total optical system length TTL of the imaging lens satisfy the following relationship: 9≤TTL / DG1_MAX≤10.4, preferably, 9.2≤TTL / DG1_MAX≤10.3. By reasonably setting the ratio of the total optical system length TTL to the maximum effective aperture of the first lens L1 to the ninth lens L9, the maximum effective aperture and the total length of the optical system can be reasonably constrained and controlled, which is beneficial to achieving lens miniaturization and making the total optical length TTL≤79mm.

[0112] In some embodiments of the present invention, the back focal length (BFL) of the imaging lens and the total optical system length (TTL) of the imaging lens satisfy the following relationship: 0.3 ≤ BFL / TTL ≤ 0.5, preferably, 0.3 ≤ BFL / TTL ≤ 0.4. While achieving miniaturization, by controlling the back focal length of the system's optical system, the back focal length of the lens is made longer, which helps to reserve space for the installation of optical components, facilitates the assembly of the imaging lens, avoids interference, and improves the assembly yield of the imaging lens.

[0113] In some embodiments of the present invention, the total optical system length TTL of the imaging lens and the effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 1.6≤TTL / FI≤2, preferably 1.7≤TTL / FI≤2. By reasonably controlling the ratio of the total optical system length TTL to the total effective focal length FI of the imaging lens at an object distance of 0.3m within a specific range, the total length of the optical system can be reasonably controlled while satisfying a certain focal length, which is beneficial to achieving lens miniaturization.

[0114] In some embodiments of the present invention, the Abbe number Vd6 of the sixth lens L6 and the Abbe number Vd5 of the fifth lens L5 satisfy the following relationship with the effective focal length FI of the imaging lens at an object distance of 0.3m: 0.15≤(Vd6-Vd5) / FI≤0.75, preferably 0.2≤(Vd6-Vd5) / FI≤0.7. By reasonably controlling the ratio of the difference in Abbe number between the sixth lens L6 and the fifth lens L5 to the total effective focal length FI of the imaging lens at an object distance of 0.3m, and by using materials with different dispersion coefficients, dispersion can be mutually compensated, thereby eliminating positional chromatic aberration and improving the imaging performance of telephoto lenses. At the same time, it can also effectively reduce the tolerance sensitivity of the optical system and improve the production yield of the lens.

[0115] In some embodiments of the present invention, the effective focal length FI of the imaging lens when the object distance is 0.3m and the effective focal length FII of the imaging lens when the object distance is infinity satisfy the following relationship: 1≤FI / FII≤1.5, preferably, 1≤FI / FII≤1.25. By reasonably controlling the ratio of the effective focal length of the optical system when the object distance is 0.3m and infinity, the smaller the ratio, the smaller the change in the field of view of the system can be effectively guaranteed within the range of object distance variation.

[0116] The imaging lens according to the present invention is described below with five specific embodiments based on the above-described configuration. The imaging lens according to the present invention has nine lenses, with each cemented surface of the cemented lens considered as one surface, plus the aperture stop STO, protective glass CG, and image plane IMA, totaling 18 or 19 surfaces. The aperture stop STO is located behind the image-side surface of the ninth lens L9. For ease of description, the lens surfaces, aperture stop STO, and protective glass CG are numbered S1, S2 to S18 or S1, S2 to S19.

[0117] The data for the five sets of examples are shown in Table 1 below:

[0118]

[0119]

[0120] Table 1

[0121] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0122] Example 1

[0123] Figure 1 This is a schematic diagram of the imaging lens in Embodiment 1 of the present invention;

[0124] Figure 2This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 1 of the present invention is 0.3m;

[0125] Figure 3 This is a schematic diagram of the distortion of the imaging lens in Embodiment 1 of the present invention when the object distance is infinity.

[0126] In Embodiment 1, the first lens L1 is a convex-plano lens with positive optical power, the second lens L2 is a plano-concave lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a concave-convex lens with negative optical power, the fifth lens L5 is a concave-convex lens with positive optical power, the sixth lens L6 is a concave-concave lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a concave-concave lens with negative optical power, and the ninth lens L9 is a convex-convex lens with positive optical power.

[0127] The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a cemented doublet lens, and the seventh lens L7, the eighth lens L8, and the ninth lens L9 form a cemented triplicate lens. The aperture stop STO is positioned behind the object side of the ninth lens L9.

[0128] The first lens L1 to the ninth lens L9 are all made of glass.

[0129] Table 2 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, radius of curvature R, thickness d, refractive index Nd of the material and Abbe number Vd.

[0130] Surface serial number Surface type radius of curvature R Thickness d Refractive index Nd Abbe number Vd S1 spherical 32.562 2.440 1.883 39.22 S2 spherical Infinity 0.500 S3 spherical Infinity 0.800 1.581 40.92 S4 spherical 17.483 14.390 S5 spherical 23.787 4.610 1.593 66.99 S6 spherical -17.221 0.700 1.603 38.01 S7 spherical -97.862 T0 S8 spherical -22.791 3.070 1.946 17.99 S9 spherical -15.506 0.700 1.548 45.83 S10 spherical 21.439 T1 S11 spherical 35.661 2.380 2.001 29.13 S12 spherical -37.04 0.700 1.741 27.76 S13 spherical 12.52 3.100 1.593 66.99 S14 spherical -37.311 0.500 S15 (STO) spherical Infinity 29.750 S16 spherical Infinity 0.900 1.517 64.21 S17 spherical Infinity 0.040 S18(IMA) spherical Infinity -

[0131] Table 2

[0132] Table 3 lists the variable spacing values ​​between the lens groups of the imaging lens in this embodiment as the object distance changes from 0.3M to infinity.

[0133] Face number thickness When the object distance is 0.3M The object distance is infinity S7 T0 10.423 4.703 S10 T1 3.998 9.718

[0134] Table 3

[0135] In Example 1, the effective focal length FI of the imaging lens is 41.71 when the object distance is 0.3m, the effective focal length FII is 37.51 when the object distance is infinity, the aperture FNO is 3.0, and the optical distortion is 0.37% to 0.11% when the object distance changes from 0.3m to infinity.

[0136] Combination Figures 1 to 3As shown in Tables 1 to 3 above, this embodiment is an imaging lens that has at least one of the following characteristics: wide object distance (clear focus at object distances from 0.3m to infinity), low distortion (absolute optical distortion ≤0.75%), high illumination (relative illumination RI ≥70%), miniaturization (total optical length TTL ≤79mm), constant aperture (FNO = 3.0), no defocusing at high and low temperatures, and no lens overheating.

[0137] Example 2

[0138] Figure 4 This is a schematic diagram of the imaging lens in Embodiment 2 of the present invention;

[0139] Figure 5 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 2 of the present invention is 0.3m;

[0140] Figure 6 This is a schematic diagram of the distortion of the imaging lens in Embodiment 2 of the present invention when the object distance is infinity.

[0141] In Embodiment 2, the first lens L1 is a convex-convex lens with positive optical power, the second lens L2 is a concave-concave lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a concave-convex lens with negative optical power, the fifth lens L5 is a convex-convex lens with positive optical power, the sixth lens L6 is a concave-concave lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a concave-concave lens with negative optical power, and the ninth lens L9 is a convex-concave lens with positive optical power.

[0142] The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a cemented doublet lens, and the seventh lens L7, the eighth lens L8, and the ninth lens L9 form a cemented triplicate lens. The aperture stop STO is positioned behind the object side of the ninth lens L9.

[0143] The first lens L1 to the ninth lens L9 are all made of glass.

[0144] Table 4 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, radius of curvature R, thickness d, refractive index Nd of the material and Abbe number Vd.

[0145]

[0146]

[0147] Table 4

[0148] Table 5 lists the variable spacing values ​​between the lens groups of the imaging lens in this embodiment as the object distance changes from 0.3M to infinity.

[0149] Face number thickness When the object distance is 0.3M The object distance is infinity S7 T0 21.982 4.002 S10 T1 4.018 21.999

[0150] Table 5

[0151] In Example 2, the effective focal length FI of the imaging lens is 40.44 when the object distance is 0.3m, the effective focal length FII is 38.08 when the object distance is infinity, the aperture FNO is 3.0, and the optical distortion when the object distance changes from 0.3m to infinity is -0.24% to -0.63%.

[0152] Combination Figures 4 to 6 As shown in Tables 1, 4 to 5 above, this second embodiment is an imaging lens that has at least one of the following characteristics: wide object distance (clear focus at object distances from 0.3m to infinity), low distortion (absolute optical distortion ≤0.75%), high illumination (relative illumination RI≥70%), miniaturization (total optical length TTL≤79mm), constant aperture (FNO=3.0), no defocusing at high and low temperatures, and no lens overheating.

[0153] Example 3

[0154] Figure 7 This is a schematic diagram of the imaging lens in Embodiment 3 of the present invention;

[0155] Figure 8 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 3 of the present invention is 0.3m;

[0156] Figure 9 This is a schematic diagram of the distortion of the imaging lens in Embodiment 3 of the present invention when the object distance is infinity.

[0157] In Embodiment 3, the first lens L1 is a convex-planar lens with positive optical power, the second lens L2 is a concave-concave lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a concave-convex lens with negative optical power, the fifth lens L5 is a concave-convex lens with positive optical power, the sixth lens L6 is a concave-concave lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a concave-concave lens with negative optical power, and the ninth lens L9 is a convex-concave lens with positive optical power.

[0158] The third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the eighth lens L8, and the ninth lens L9 each form a cemented doublet. The aperture stop STO is positioned behind the object side of the ninth lens L9.

[0159] The first lens L1 to the ninth lens L9 are all made of glass.

[0160] Table 6 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, radius of curvature R, thickness d, refractive index Nd of the material and Abbe number Vd.

[0161] Surface serial number Surface type radius of curvature R Thickness d Refractive index Nd Abbe number Vd S1 spherical 36.212 2.330 1.871 40.73 S2 spherical Infinity 1.090 S3 spherical -47.519 0.700 1.620 36.35 S4 spherical 28.754 11.440 S5 spherical 56.035 3.790 1.593 66.99 S6 spherical -20.690 0.700 1.581 40.92 S7 spherical -42.181 T0 S8 spherical -145.915 1.830 1.946 17.99 S9 spherical -46.714 0.700 1.581 40.92 S10 spherical 29.787 T1 S11 spherical 21.017 2.530 2.001 29.13 S12 spherical -100.000 1.130 S13 spherical -65.762 0.700 1.741 27.76 S14 spherical 9.304 2.780 1.593 68.35 S15 spherical 90.129 0.320 S16(STO) spherical Infinity 27.060 S17 spherical Infinity 0.900 1.517 64.21 S18 spherical Infinity 0.040 S19(IMA) spherical Infinity -

[0162] Table 6

[0163] Table 7 lists the variable spacing values ​​between the lens groups of the imaging lens in this embodiment as the object distance changes from 0.3M to infinity.

[0164] Face number thickness Wide-angle end telephoto end S7 T0 16.963 4.168 S10 T1 3.998 16.793

[0165] Table 7

[0166] In Example 3, the effective focal length FI of the imaging lens is 41.09 when the object distance is 0.3m, the effective focal length FII is 37.53 when the object distance is infinity, the aperture FNO is 3.0, and the optical distortion when the object distance changes from 0.3m to infinity is -0.22% to -0.72%.

[0167] Combination Figures 7 to 9 As shown in Tables 1, 6 and 7 above, this third embodiment is an imaging lens that has at least one of the following characteristics: wide object distance (clear focus at object distances from 0.3m to infinity), low distortion (absolute optical distortion ≤0.75%), high illumination (relative illumination RI≥70%), miniaturization (total optical length TTL≤79mm), constant aperture (FNO=3.0), no defocusing at high and low temperatures, and no lens overheating.

[0168] Example 4

[0169] Figure 10 This is a schematic diagram of the imaging lens in Embodiment 4 of the present invention;

[0170] Figure 11 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 4 of the present invention is 0.3m;

[0171] Figure 12 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 4 of the present invention is infinity.

[0172] In Embodiment 4, the first lens L1 is a convex-concave lens with positive optical power, the second lens L2 is a concave-concave lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a concave-concave lens with negative optical power, the fifth lens L5 is a concave-convex lens with positive optical power, the sixth lens L6 is a concave-concave lens with negative optical power, the seventh lens L7 is a concave-concave lens with negative optical power, the eighth lens L8 is a convex-convex lens with positive optical power, and the ninth lens L9 is a convex-convex lens with positive optical power.

[0173] The third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 form a cemented doublet. The aperture stop STO is positioned behind the object side of the ninth lens L9.

[0174] The first lens L1 to the ninth lens L9 are all made of glass.

[0175] Table 8 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, radius of curvature R, thickness d, refractive index Nd of the material, and Abbe number Vd.

[0176]

[0177]

[0178] Table 8

[0179] Table 9 lists the variable spacing values ​​between the lens groups of the imaging lens in this embodiment as the object distance changes from 0.3M to infinity.

[0180] Face number thickness Wide-angle end telephoto end S7 T0 17.000 4.207 S10 T1 8.262 21.056

[0181] Table 9

[0182] In Example 4, the effective focal length FI of the imaging lens is 45.78 when the object distance is 0.3m, the effective focal length FII is 38.10 when the object distance is infinity, the aperture FNO is 3.0, and the optical distortion when the object distance changes from 0.3m to infinity is 0.03% to -0.35%.

[0183] Combination Figures 10 to 12 As shown in Tables 1, 8 and 9 above, this embodiment four is an imaging lens that has at least one of the following characteristics: wide object distance (clear focus at object distances from 0.3m to infinity), low distortion (absolute optical distortion ≤0.75%), high illumination (relative illumination RI≥70%), miniaturization (total optical length TTL≤79mm), constant aperture (FNO=3.0), no defocusing at high and low temperatures, and no lens overheating.

[0184] Example 5

[0185] Figure 13 This is a schematic diagram of the imaging lens in Embodiment 5 of the present invention;

[0186] Figure 14 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 5 of the present invention is 0.3m;

[0187] Figure 15 This is a schematic diagram of distortion when the object distance of the imaging lens in Embodiment 5 of the present invention is infinity.

[0188] In Embodiment 5, the first lens L1 is a convex-planar lens with positive optical power, the second lens L2 is a concave-concave lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a concave-convex lens with negative optical power, the fifth lens L5 is a concave-convex lens with positive optical power, the sixth lens L6 is a concave-concave lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a concave-concave lens with negative optical power, and the ninth lens L9 is a convex-concave lens with positive optical power.

[0189] The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a cemented doublet lens, and the seventh lens L7, the eighth lens L8, and the ninth lens L9 form a cemented triplicate lens. The aperture stop STO is positioned behind the object side of the ninth lens L9.

[0190] The first lens L1 to the ninth lens L9 are all made of glass.

[0191] Table 10 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, radius of curvature R, thickness d, refractive index Nd of the material, and Abbe number Vd.

[0192] Surface serial number Surface type radius of curvature R Thickness d Refractive index Nd Abbe number Vd S1 spherical 30.883 2.480 1.835 42.73 S2 spherical Infinity 4.120 S3 spherical -45.701 0.800 1.620 36.35 S4 spherical 19.242 9.580 S5 spherical 41.868 4.320 1.593 66.99 S6 spherical -15.141 0.700 1.517 52.19 S7 spherical -44.44 T0 S8 spherical -120.516 1.730 1.946 17.99 S9 spherical -46.567 0.700 1.581 40.92 S10 spherical 28.004 T1 S11 spherical 23.408 2.380 2.001 29.13 S12 spherical -61.846 0.700 1.699 30.05 S13 spherical 9.046 2.830 1.593 66.99 S14 spherical 95.514 0.620 S15 (STO) spherical Infinity 26.750 S16 spherical Infinity 0.900 1.517 64.21 S17 spherical Infinity 0.040 S18(IMA) spherical Infinity 0

[0193] Table 10

[0194] Table 11 lists the variable spacing values ​​between the lens groups of the imaging lens in this embodiment as the object distance changes from 0.3M to infinity.

[0195] Face number thickness Wide-angle end telephoto end S7 T0 16.354 4.150 S10 T1 3.998 16.202

[0196] Table 11

[0197] In Example 5, the effective focal length FI of the imaging lens is 41.90 when the object distance is 0.3m, the effective focal length FII is 37.52 when the object distance is infinity, the aperture FNO is 3.0, and the optical distortion when the object distance changes from 0.3m to infinity is -0.18% to -0.61%.

[0198] Combination Figures 13 to 15 As shown in Tables 1, 10 and 11 above, this fifth embodiment is an imaging lens that has at least one of the following characteristics: wide object distance (clear focus at object distances from 0.3m to infinity), low distortion (absolute optical distortion ≤0.75%), high illumination (relative illumination RI ≥70%), miniaturization (total optical length TTL ≤79mm), constant aperture (FNO = 3.0), no defocusing at high and low temperatures, and no lens overheating.

[0199] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An imaging lens, characterized in that, Along the optical axis from the object side to the image side, there are three lens groups in total: a first lens group (G1) with positive optical power, a second lens group (G2) with negative optical power, and a third lens group (G3) with positive optical power. The first lens group (G1) and the third lens group are fixed lens groups, and the second lens group (G2) is a focusing group that moves along the optical axis of the imaging lens. The first lens group (G1) includes, in sequence, a first lens (L1) with positive optical power, a second lens (L2) with negative optical power, a third lens (L3) with positive optical power, and a fourth lens (L4) with negative optical power, for a total of four lenses; The second lens group (G2) consists of two lenses: a fifth lens (L5) with positive optical power and a sixth lens (L6) with negative optical power. The third lens group (G3) includes, in sequence, a seventh lens (L7), an eighth lens (L8), and a ninth lens (L9) with positive optical power, for a total of three lenses; the seventh lens (L7) and the eighth lens (L8) have opposite optical powers; The object-side surface of the first lens (L1) is convex, the image-side surface of the second lens (L2) is concave, the third lens (L3) is a convex-convex lens, and the object-side surface of the fourth lens (L4) is concave. The image-side surface of the fifth lens (L5) is convex; the sixth lens (L6) is a concave-concave lens; The object-side surface of the ninth lens (L9) is convex.

2. The imaging lens according to claim 1, characterized in that, The third lens (L3) and the fourth lens (L4) form a cemented doublet lens, and the fifth lens (L5) and the sixth lens (L6) form a cemented doublet lens.

3. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length FG1 of the first lens group (G1) and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.8≤FG1 / FI≤1.

7.

4. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length FG3 of the third lens group (G3) and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.5≤FG3 / FI≤1.

1.

5. The imaging lens according to claim 1 or 2, characterized in that, The focusing distance d2 of the second lens group (G2) within the range of object distance variation satisfies the following relationship with the effective focal length FG2 of the second lens group (G2): -5.6≤FG2 / d2≤-3.

6.

6. The imaging lens according to claim 1 or 2, characterized in that, The air gap distance d23 between the second lens (L2) and the third lens (L3) on the optical axis satisfies the following relationship with the effective focal length FG1 of the first lens group (G1): 2.5≤FG1 / d23≤120.

7. The imaging lens according to claim 1 or 2, characterized in that, The combined effective focal length F34 of the third lens (L3) and the fourth lens (L4) satisfies the following relationship with the effective focal length FG1 of the first lens group (G1): 0.2≤F34 / FG1≤1.

1.

8. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length F1 of the first lens (L1) and the effective focal length FG1 of the first lens group (G1) satisfy the following relationship: 0.95≤FG1 / F1≤1.

7.

9. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length FG1 of the first lens group (G1) and the effective focal length F2 of the second lens (L2) satisfy the following relationship: -2.85≤FG1 / F2≤-1.

10. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length F4 of the fourth lens (L4) and the effective focal length F3 of the third lens (L3) satisfy the following relationship: -3.4≤F4 / F3≤-1.

6.

11. The imaging lens according to claim 1 or 2, characterized in that, The Abbe number Vd3 of the third lens (L3) and the effective focal length F3 of the third lens (L3) satisfy the following relationship: 2.4≤Vd3 / F3≤4.

12. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length F5 of the fifth lens (L5) and the effective focal length F6 of the sixth lens (L6) satisfy the following relationship: -2.8≤F5 / F6≤-1.

3.

13. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length FG3 of the third lens group (G3) and the effective focal length F7 of the seventh lens (L7), the effective focal length F8 of the eighth lens (L8), and the effective focal length F9 of the ninth lens (L9) satisfy the following relationship: 0.8≤FG3 / (F7+F8+F9)≤1.

9.

14. The imaging lens according to claim 1 or 2, characterized in that, The maximum effective aperture of the lens DG1_MAX of the first lens (L1) to the ninth lens (L9) and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 4.87≤FI / DG1_MAX≤5.

6.

15. The imaging lens according to claim 1 or 2, characterized in that, The maximum effective aperture DG1_MAX of the lens from the first lens (L1) to the ninth lens (L9) and the total optical system length TTL of the imaging lens satisfy the following relationship: 9≤TTL / DG1_MAX≤10.

4.

16. The imaging lens according to claim 1 or 2, characterized in that, The back focal length BFL of the imaging lens and the total optical system length TTL of the imaging lens satisfy the following relationship: 0.3≤BFL / TTL≤0.

5.

17. The imaging lens according to claim 1 or 2, characterized in that, The total optical system length TTL of the imaging lens and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 1.6≤TTL / FI≤2.

18. The imaging lens according to claim 1 or 2, characterized in that, The Abbe number Vd6 of the sixth lens (L6), the Abbe number Vd5 of the fifth lens (L5), and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: 0.15≤(Vd6-Vd5) / FI≤0.

75.

19. The imaging lens according to claim 1 or 2, characterized in that, The total effective focal length FI of the imaging lens at an object distance of 0.3m and the effective focal length FII of the imaging lens at an object distance of infinity satisfy the following relationship: 1≤FI / FII≤1.

5.

20. The imaging lens according to claim 1 or 2, characterized in that, The effective focal length FG2 of the second lens group (G2) and the total effective focal length FI of the imaging lens at an object distance of 0.3m satisfy the following relationship: -2.4≤FG2 / FI≤-0.

3.

21. The imaging lens according to claim 6, characterized in that, The air gap distance d23 between the second lens (L2) and the third lens (L3) on the optical axis satisfies the following relationship with the effective focal length FG1 of the first lens group (G1): 2.5≤FG1 / d23≤9.

22. The imaging lens according to claim 1, characterized in that, The imaging lens must meet at least one of the following conditions: 0.88≤FG1 / FI≤1.63 -2.2≤FG2 / FI≤-0.5, 0.95≤FG3 / FI≤0.65 -5.4≤FG2 / d2≤-3.9, 2.6≤FG1 / d23≤8.55, 0.2≤F34 / FG1≤1.05, 1≤FG1 / F1≤1.6, -2.7≤FG1 / F2≤-1.2, -3.2≤F4 / F3≤-1.8, 2.55≤Vd3 / F3≤3.85, -2.65≤F5 / F6≤-1.5, 1.0≤FG3 / (F7+F8+F9)≤1.85, 4.9≤FI / DG1_MAX≤5.5 9.2≤TTL / DG1_MAX≤10.3 0.3≤BFL / TTL≤0.4 1.7≤TTL / FI≤2 0.2≤(Vd6-Vd5) / FI≤0.7, 1≤FI / FII≤1.25, in, FI is the total effective focal length of the imaging lens at an object distance of 0.3m; FG1 is the effective focal length of the first lens group (G1); FG2 is the effective focal length of the second lens group (G2); FG3 is the effective focal length of the third lens group (G3); d2 is the focusing distance of the second lens group (G2) within the range of object distance variation; d23 is the air gap distance between the second lens (L2) and the third lens (L3) on the optical axis; F34 is the combined effective focal length of the third lens (L3) and the fourth lens (L4); F1 is the effective focal length of the first lens (L1); F2 is the effective focal length of the second lens (L2); F3 is the effective focal length of the third lens (L3); and F4 is the effective focal length of the fourth lens (L4). The effective focal length of (L4), Vd3 is the Abbe number of the third lens (L3), F5 is the effective focal length of the fifth lens (L5), F6 is the effective focal length of the sixth lens (L6), F7 is the effective focal length of the seventh lens (L7), F8 is the effective focal length of the eighth lens (L8), F9 is the effective focal length of the ninth lens (L9), DG1_MAX is the maximum effective aperture of the lens from the first lens (L1) to the ninth lens (L9), TTL is the total length of the optical system of the imaging lens, BFL is the back focal length of the imaging lens, Vd6 is the Abbe number of the sixth lens (L6), Vd5 is the Abbe number of the fifth lens (L5), and FII is the effective focal length of the imaging lens when the object distance is infinity.

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