Imaging lens

Abstract

The utility model relates to an imaging lens, which sequentially comprises a first lens group with positive focal power, a second lens group with negative focal power and a third lens group with positive focal power along an optical axis from an object side to an image side, the first lens group and the third lens group are fixed lens groups, and the second lens group is a focusing group; the first lens group comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power and a fourth lens with negative focal power; the second lens group comprises a fifth lens with positive focal power and a sixth lens with negative focal power; the third lens group comprises a seventh lens, an eighth lens and a ninth lens, wherein the seventh lens and the eighth lens are opposite in focal power, and the ninth lens is positive in focal power. The imaging lens at least has one of the characteristics of wide object distance, low distortion, high illumination, no virtual focus at high temperature, athermalization and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial lenses, in particular to an imaging lens with wide object distance, low distortion, high illumination, no defocusing at high temperature and no thermalization. Background Art

[0002] Industrial lenses are indispensable components in machine vision systems. They play a key role in applications such as automated inspection, quality control, measurement, and identification.

[0003] The industrial lenses on the market today still have the following shortcomings:

[0004] 1. The existing lens has a narrow focus distance range and does not meet the requirements of multi-scene use;

[0005] 2. The existing lens has large distortion, which causes the image to be distorted to a large extent;

[0006] 3. The existing lens has low illumination, which makes the image darker and the color saturation lower;

[0007] 4. When existing lenses are used to capture and observe objects at long distances, the image clarity is low;

[0008] 5. The focus of existing lenses drifts in high and low temperature environments, and the imaging effect is seriously affected by the environment.

[0009] Therefore, designing an imaging lens that meets at least one of the following characteristics: wide focus distance range, low distortion, high illumination, no defocusing at high temperature, and no thermalization has become a market development trend. Utility Model Content

[0010] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an imaging lens having at least one of the following characteristics: wide object distance, low distortion, high illumination, no defocusing at high temperature, and no athermalization.

[0011] To achieve the above-mentioned object, the present invention provides an imaging lens, comprising, along the optical axis from the object side to the image side, a first lens group having positive optical power, a second lens group having negative optical power, and a third lens group having positive optical power, wherein the first lens group and the third lens group are fixed lens groups, and the second lens group is a focus adjustment group that moves along the optical axis of the imaging lens;

[0012] The first lens group includes, in order: 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; the object side surface of the fourth lens is concave;

[0013] The second lens group includes, in order: a fifth lens having positive optical power and a sixth lens having negative optical power, a total of two lenses; the sixth lens is a concave-concave lens;

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

[0015] According to a 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 a technical solution of the present invention, the image-side surface of the fifth lens is a convex surface; and the sixth lens is a concave-concave lens.

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

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

[0019] According to a technical solution of the present utility model, at least two lenses among the seventh lens, the eighth lens and the ninth lens cooperate to form a cemented lens.

[0020] According to a technical solution of the present invention, the aperture is arranged behind the image side surface of the ninth lens.

[0021] According to a technical solution of the present invention, the first lens to the ninth lens are all made of glass lenses.

[0022] According to a 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 when the object distance is 0.3m satisfy the following relationship: 0.8≤FG1 / FI≤1.7.

[0023] According to a 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 when the object distance is 0.3m satisfy the following relationship: -2.4≤FG2 / FI≤-0.3.

[0024] According to a 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 when the object distance is 0.3m satisfy the following relationship: 0.5≤FG3 / FI≤1.1.

[0025] According to a technical solution of the present invention, the focus 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.

[0026] According to a technical solution of the present invention, the air spacing 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.

[0027] According to a technical solution of the present invention, the air spacing 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≤9.

[0028] According to a technical solution of the present invention, the combined effective focal length F34 of the third lens and the fourth lens and the effective focal length FG1 of the first lens group satisfy the following relationship: 0.2≤F34 / FG1≤1.1.

[0029] According to a 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.

[0030] According to a 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 group satisfy the following relationship: -2.85≤FG1 / F2≤-1.

[0031] According to a 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.

[0032] According to a 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.

[0033] According to a 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.

[0034] According to a technical solution of the present invention, the effective focal length FG3 of the third lens group and 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.

[0035] According to a technical solution of the present invention, the maximum effective light aperture DG1_MAX of the lenses from the first lens to the ninth lens and the total effective focal length FI of the imaging lens when the object distance is 0.3m satisfy the following relationship: 4.87≤FI / DG1_MAX≤5.6.

[0036] According to a technical solution of the present invention, the maximum effective light aperture DG1_MAX of the lenses from 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.

[0037] According to a 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.

[0038] According to a 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 when the object distance is 0.3m satisfy the following relationship: 1.6≤TTL / FI≤2.

[0039] According to a 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 when the object distance is 0.3m satisfy the following relationship: 0.15≤(Vd6-Vd5) / FI≤0.75.

[0040] According to a technical solution of the present invention, the total 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 infinite satisfy the following relationship: 1≤FI / FII≤1.5.

[0041] According to a technical solution of the present invention, the imaging lens satisfies at least one of the following conditions:

[0042] 0.88≤FG1 / FI≤1.63,

[0043] -2.2≤FG2 / FI≤-0.5,

[0044] 0.95≤FG3 / FI≤0.65,

[0045] -5.4≤FG2 / d2≤-3.9,

[0046] 2.6≤FG1 / d23≤8.55,

[0047] 0.2≤F34 / FG1≤1.05,

[0048] 1≤FG1 / F1≤1.6,

[0049] -2.7≤FG1 / F2≤-1.2,

[0050] -3.2≤F4 / F3≤-1.8,

[0051] 2.6≤Vd3 / F3≤3.85,

[0052] -2.65≤F5 / F6≤-1.5,

[0053] 1.0≤FG3 / (F7+F8+F9)≤1.85,

[0054] 4.9≤FI / DG1_MAX≤5.5,

[0055] 9.2≤TTL / DG1_MAX≤10.3,

[0056] 0.3≤BFL / TTL≤0.4,

[0057] 1.7≤TTL / FI≤2,

[0058] 0.2≤(Vd6-Vd5) / FI≤0.7,

[0059] 1≤FI / FII≤1.25,

[0060] Wherein, FI is the total effective focal length of the imaging lens at an object distance of 0.3 m, 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 focus movement distance of the second lens group within the object distance variation range, d23 is the air separation 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. wherein, 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 clear aperture of the lenses 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.

[0061] According to the solution of the present invention, by setting the number and optical focal length of the imaging lenses, the ultra-wide-angle lens has at least one of the following beneficial effects: wide working distance (clear focus can be achieved from 0.3m to infinity object distance), low distortion (absolute value of optical distortion ≤0.75%), high illumination (relative illumination RI ≥70%), and miniaturization (total optical length TTL ≤79mm); the diaphragm is positioned rearward 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 be kept in focus without blurring in the temperature range of -40°C to 80°C, achieving athermalization of the lens and being suitable for various high and low temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0063] Figure 1 Schematic diagram of the structure of the imaging lens of Example 1 of the present utility model;

[0064] Figure 2 Schematic diagram of distortion of the imaging lens of Example 1 of the present invention when the object distance is 0.3m;

[0065] Figure 3 Schematic diagram of distortion of the imaging lens of Example 1 of the present invention when the object distance is infinite;

[0066] Figure 4 Schematic diagram of the structure of the imaging lens of Example 2 of the present utility model;

[0067] Figure 5 Schematic diagram of distortion of the imaging lens of Example 2 of the present invention when the object distance is 0.3m;

[0068] Figure 6 Schematic diagram of distortion of the imaging lens of Example 2 of the present invention when the object distance is infinite;

[0069] Figure 7 This is a schematic structural diagram of an imaging lens according to a third embodiment of the present invention;

[0070] Figure 8 Schematic diagram of distortion of the imaging lens of Example 3 of the present invention when the object distance is 0.3m;

[0071] Figure 9 Schematic diagram of the distortion of the imaging lens of Example 3 of the present invention when the object distance is infinite.

[0072] Figure 10 Schematic diagram of the structure of the imaging lens of Example 4 of the present utility model;

[0073] Figure 11 Schematic diagram of distortion of the imaging lens of Example 4 of the present invention when the object distance is 0.3m;

[0074] Figure 12 Schematic diagram of distortion of the imaging lens of Example 4 of the present invention when the object distance is infinite;

[0075] Figure 13 Schematic diagram of the structure of the imaging lens of Example 5 of the present utility model;

[0076] Figure 14 Schematic diagram of distortion of the imaging lens of Example 5 of the present invention when the object distance is 0.3m;

[0077] Figure 15 Schematic diagram of the distortion of the imaging lens of Example 5 of the present invention when the object distance is infinite. DETAILED DESCRIPTION

[0078] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present 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.

[0079] 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. 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.

[0080] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0081] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, 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.

[0082] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0083] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0084] 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 following examples only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they should not be understood as limiting the scope of the patent application. It should be pointed out that for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all fall within the scope of protection of the present application.

[0085] like Figures 1 to 15 As shown, an embodiment of the present invention provides an imaging lens, which includes, along the optical axis from the object side to the image side,: 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.

[0086] Among them, the first lens group G1 is a fixed front group, and the first lens group G1 has positive optical power, which is conducive to converging incident light into the optical system, effectively controlling the direction of light, balancing the spherical aberration and coma generated by the optical system, compensating for system chromatic aberration, and ensuring the image 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.

[0087] The second lens group G2 is a focusing group with 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 support 0.3M to infinity, meeting the requirements of a wider range of working distances.

[0088] The third lens group G3 is a fixed rear group with positive optical power. Its position relative to the image plane is fixed, effectively controlling the trajectory of light, ensuring a smooth transition to the image plane. This corrects the optical system's astigmatism and field curvature, reduces the system's sensitivity to tolerances, and helps ensure the lens's resolution quality and improve production yield. It also effectively compensates for the optical system's on-axis chromatic aberration, ensuring color reproduction in the image.

[0089] In the embodiment of the present invention, along the direction from the object side to the image side of the optical axis, the first lens group G1 includes: a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4, a total of four lenses.

[0090] The object-side surface of the first lens L1 is convex and has positive refractive power, which is conducive to converging incident light into the optical system.

[0091] The image-side surface of the second lens element L2 is concave and has negative optical power, which helps to diverge the light after passing through the second lens element L2, effectively controlling the direction of the light and making the light direction better cooperate with the large-aperture third lens element L3 and fourth lens element L4. It also helps to reduce the distortion of the optical system, making the absolute value of the optical distortion of the lens ≤ 0.75%.

[0092] The third lens element, L3, is a convex-convex lens with positive optical power. The fourth lens element, L4, has a concave object-side surface and negative optical power. The combination of positive and negative optical powers, along with a large aperture, facilitates chromatic aberration correction and improves the imaging performance of the telephoto lens. The third and fourth lenses, L3 and L4, can be combined to form a cemented doublet. This doublet effectively reduces the optical system's sensitivity to tolerances and improves lens production yield.

[0093] In the embodiment of the present invention, along the direction from the object side to the image side of the optical axis, the second lens group G2 includes a fifth lens L5 and a sixth lens L6 in sequence, for a total of two lenses.

[0094] The image-side surface of the fifth lens element L5 is convex and has positive optical power; the sixth lens element L6 is a concave-concave lens with negative optical power. The fifth and sixth lenses L5, L6 utilize a combination of positive and negative optical powers. High-dispersion materials are preferred for the fifth lens element L5, while low-dispersion materials are preferred for the sixth lens element L6. The use of 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 and sixth lenses L5, L6 can be combined to form a cemented doublet. This doublet effectively reduces the tolerance sensitivity of the optical system and improves the lens production yield.

[0095] The third lens group G3 includes, in order: a seventh lens L7, an eighth lens L8 and a ninth lens L9, a total of three lenses.

[0096] The seventh and eighth lenses, L7 and L8, have opposite optical powers, while the object-side surface of the ninth lens, L9, is convex and has positive optical power. By rationally arranging the optical powers of the seventh, eighth, and ninth lenses, L7, L8, and L9, and matching their positive-negative-positive or negative-positive optical powers, this facilitates the mutual compensation of positive and negative spherical aberrations, simultaneously correcting system astigmatism and field curvature, and improving lens resolution. Furthermore, it effectively controls the trajectory of light, ensuring a smooth transition and reducing the tolerance sensitivity of the fixed rear group.

[0097] The seventh lens element L7, the eighth lens element L8, and the ninth lens element L9 can be combined into a triplet lens, or a combination of a single lens element and a doublet lens. This effectively balances axial chromatic aberration, improves the resolution of the lens, and effectively reduces the tolerance sensitivity of the fixed rear lens group, thereby improving production yield.

[0098] The utility model adopts a constant aperture, and can maintain a constant aperture during the focusing process within the object distance range of 0.3m to infinity, which is conducive to ensuring that the resolution does not decrease and the imaging picture is transparent.

[0099] This new focusing lens architecture, featuring three lens groups (positive, negative, and positive) and a single aperture, effectively meets the requirements of use within an object distance range of 0.3m to infinity. It also facilitates correction of field curvature and distortion, reduces system sensitivity to tolerances, eliminates chromatic aberration, and reduces the occurrence of purple fringing. The rational combination of group focal lengths allows light to smoothly pass through the lens, significantly correcting higher-order aberrations and improving image quality. Furthermore, it facilitates continuous variation of the focusing lens group within the object distance range of 0.3m to infinity, compensating for aberrations introduced during zoom movement and effectively ensuring image clarity at varying object distances.

[0100] In some embodiments of the present invention, the first lens L1 through 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 with temperature changes, thereby improving system stability. At the same time, the use of glass can avoid lens imaging blur caused by high and low temperature changes in the operating environment, which affects the normal use of the lens, and is conducive to achieving athermalization of the lens. It can also better correct system chromatic aberration and improve lens resolution. In some embodiments of the present invention, the first lens L1 through the ninth lens L9 are all made of glass. The all-glass design of the imaging lens has a wide temperature range and can maintain stable optical performance within the range of -40°C to 85°C.

[0101] 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. Properly 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 facilitates focusing incident light entering the optical system, effectively controls the trajectory of light, and helps compensate for spherical aberration, coma, and axial chromatic aberration of the optical system, thereby improving the imaging quality of the lens.

[0102] 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 properly 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, the lens can be extended to support a wide working distance range from 0.3m to infinity, meeting the requirements of a wide working distance range.

[0103] 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 rationally 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 trajectory of light can be effectively controlled, ensuring a smooth transition to the image plane. This corrects astigmatism and field curvature of the optical system, reduces the tolerance sensitivity of the optical system, helps ensure lens resolution quality, and improves production yield. Furthermore, it effectively compensates for axial chromatic aberration of the optical system, ensuring color reproduction of the imaged image.

[0104] In some embodiments of the present invention, the focus shift distance d2 of the second lens group G2 within the object distance 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 properly controlling the ratio of the effective focal length FG2 of the second lens group G2 to the focus shift distance d2 of the second lens group G2 within the object distance range, it is advantageous to properly control the focus shift distance of the second lens group G2, thereby effectively limiting the length of the imaging lens while meeting the requirements of a wide range of working distances. This facilitates miniaturization of the imaging lens and improves the focusing response speed of the lens. Furthermore, it effectively ensures the tolerance sensitivity of the optical system.

[0105] In some embodiments of the present invention, the 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. Properly controlling the distance d23 between the second lens L2 and the third lens L3 in the first lens group G1 on the optical axis can effectively control the trajectory of light, reduce the angle of light deflection entering the object side of the third lens L3, and better coordinate the light trajectory with the large-aperture third lens L3 and fourth lens L4.

[0106] In some embodiments of the present invention, 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, preferably, 0.2 ≤ F34 / FG1 ≤ 1.05. By properly 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, chromatic aberration correction is facilitated, while positive spherical aberration is introduced to compensate for spherical aberration, improving the imaging performance of the telephoto lens. It also effectively reduces residual thermal differences in the optical system, ensuring athermalization of the lens.

[0107] In some embodiments of the present invention, the effective focal length F1 of first lens group G1 and the effective focal length FG1 of first lens group G1 satisfy the following relationship: 0.95 ≤ FG1 / F1 ≤ 1.7, preferably, 1 ≤ FG1 / F1 ≤ 1.6. Properly controlling the ratio of the effective focal length FG1 of first lens group G1 to the effective focal length F1 of first lens group L1 facilitates focusing incident light entering the optical system, expanding the field of view to meet design requirements.

[0108] 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 element L2 satisfy the following relationship: -2.85 ≤ FG1 / F2 ≤ -1, preferably, -2.7 ≤ FG1 / F2 ≤ -1.2. Properly controlling the effective focal length FG1 of the first lens group G1 and the effective focal length F2 of the second lens element L2 facilitates the divergence of light after passing through the second lens element L2, effectively controlling the light's trajectory and enabling better coordination with the large-aperture third and fourth lens elements L3 and L4. This also helps reduce optical system distortion, ensuring that the absolute value of the optical distortion is ≤ 0.75%.

[0109] In some embodiments of the present invention, the effective focal length F4 of the fourth lens element L4 and the effective focal length F3 of the third lens element L3 satisfy the following relationship: -3.4 ≤ F4 / F3 ≤ -1.6, preferably, -3.2 ≤ F4 / F3 ≤ -1.8. By configuring the two lenses with positive and negative focal powers, the alignment of the two lenses effectively controls the trajectory of light, facilitating the convergence of light after passing through the third lens element L3 and the fourth lens element L4. This facilitates chromatic aberration correction in the optical system and improves the imaging performance of the telephoto lens. It also effectively reduces the tolerance sensitivity of the optical system and increases the production yield of the lens.

[0110] In some embodiments of the present invention, the Abbe number Vd3 of the third lens element L3 and its effective focal length F3 satisfy the following relationship: 2.4 ≤ Vd3 / F3 ≤ 4, preferably, 2.6 ≤ Vd3 / F3 ≤ 3.85. Properly controlling the ratio of the Abbe number Vd3 of the third lens element L3 to its effective focal length F3 and selecting a low-dispersion glass material for the third lens element L3 facilitates correction of system chromatic aberration. It also helps ensure the optical system is insensitive to changes in ambient temperature and object distance, effectively reducing residual thermal differences in the optical system, and achieving athermalization, making the lens suitable for a variety of environments.

[0111] In some embodiments of the present invention, the effective focal length F5 of the fifth lens element L5 and the effective focal length F6 of the sixth lens element L6 satisfy the following relationship: -2.8 ≤ F5 / F6 ≤ -1.3, preferably, -2.65 ≤ F5 / F6 ≤ -1.5. By properly controlling the ratio of the effective focal lengths of the fifth lens element L5 to the sixth lens element L6 and employing a combination of positive and negative power lenses, chromatic aberration of the optical system over a range of varying object distances can be effectively corrected, while also reducing the optical system's sensitivity to tolerances and improving the production yield of the lenses.

[0112] In some embodiments of the present invention, the effective focal length FG3 of the third lens group G3, the effective focal length F7 of the seventh lens element L7, the effective focal length F8 of the eighth lens element L8, and the effective focal length F9 of the ninth lens element L9 satisfy the following relationship: 0.8 ≤ FG3 / (F7 + F8 + F9) ≤ 1.9, preferably, 1.0 ≤ FG3 / (F7 + F8 + F9) ≤ 1.85. Properly setting the focal powers of the seventh lens element L7, the eighth lens element L8, and the ninth lens element L9 facilitates the mutual compensation of positive and negative spherical aberrations, corrects system astigmatism and field curvature, and improves lens resolution. It also effectively controls the trajectory of light, ensuring a smooth transition, effectively reducing the tolerance sensitivity of the fixed rear lens group, and improving production yield.

[0113] In some embodiments of the present invention, the maximum effective optical aperture DG1_MAX of the first through ninth lenses L1 through 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. Properly 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 optical aperture DG1_MAX of the first through ninth lenses L1 through L9, and setting a larger optical aperture, can help improve chromatic aberration of the optical system and enhance the imaging performance of the lens.

[0114] In some embodiments of the present invention, the maximum effective optical aperture DG1_MAX of lens elements L1 through 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 properly setting the ratio of the total optical system length TTL to the maximum effective optical aperture of lens elements L1 through L9, the maximum effective optical aperture and the total optical system length can be properly controlled, facilitating lens miniaturization and minimizing the total optical system length TTL to 79 mm or less.

[0115] 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. By controlling the optical back focal length of the system while achieving miniaturization, the lens back focal length is increased, which helps reserve space for optical component installation, facilitates assembly of the imaging lens, avoids interference, and improves the assembly yield of the imaging lens.

[0116] 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 when the object distance is 0.3 m satisfy the following relationship: 1.6≤TTL / FI≤2, preferably, 1.7≤TTL / FI≤2. The ratio of the total optical system length TTL to the total effective focal length FI of the imaging lens when the object distance is 0.3 m is reasonably controlled within a specific range, so that the total length of the optical system can be reasonably controlled on the basis of meeting a certain focal length, which is conducive to miniaturization of the lens.

[0117] 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 when the object distance is 0.3 m: 0.15≤(Vd6-Vd5) / FI≤0.75, preferably, 0.2≤(Vd6-Vd5) / FI≤0.7. By rationally controlling the ratio of the difference in the Abbe numbers of the sixth lens L6 and the fifth lens L5 to the total effective focal length FI of the imaging lens when the object distance is 0.3 m and using materials with different chromatic aberration coefficients, the dispersions can be compensated for each other, thereby eliminating positional chromatic aberration, which is beneficial to improving the imaging performance of the telephoto lens; at the same time, it can also effectively reduce the tolerance sensitivity of the optical system and improve the production yield of the lens.

[0118] In some embodiments of the present invention, the effective focal length FI of the imaging lens when the object distance is 0.3 m 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. The ratio of the effective focal lengths of the optical system when the object distance is 0.3 m and infinity is reasonably controlled. When the ratio value is smaller, the change in the system field of view angle of the lens within the range of object distance change can be effectively ensured.

[0119] Based on the above-described configuration of the present invention, five specific embodiments are presented below to illustrate the imaging lens according to the present invention. The imaging lens according to the present invention comprises nine lenses, with each cemented surface of the cemented lens being referred to as a surface. Together with the aperture stop STO, the protective glass CG, and the image surface IMA, this results in a total of 18 or 19 surfaces. The aperture stop STO is positioned behind the image-side surface of the ninth lens element L9. For ease of description, the lens surfaces, the aperture stop STO, and the protective glass CG are numbered S1, S2 to S18 or S1, S2 to S19.

[0120] The data of the five groups of examples are shown in Table 1 below:

[0121]

[0122]

[0123] Table 1

[0124] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0125] Example 1

[0126] Figure 1 Schematic diagram of the structure of the imaging lens of Example 1 of the present utility model;

[0127] Figure 2 Schematic diagram of distortion of the imaging lens of Example 1 of the present invention when the object distance is 0.3m;

[0128] Figure 3 Schematic diagram of the distortion of the imaging lens of Example 1 of the present invention when the object distance is infinite.

[0129] In Example 1, the first lens L1 is a convex-plano lens with positive optical power, the second lens L2 is a meniscus lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a meniscus lens with negative optical power, the fifth lens L5 is a meniscus lens with positive optical power, the sixth lens L6 is a meniscus lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a meniscus lens with negative optical power, and the ninth lens L9 is a convex-convex lens with positive optical power.

[0130] The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a doublet, and the seventh lens L7, the eighth lens L8, and the ninth lens L9 form a triplet. A stop STO is provided behind the object-side surface of the ninth lens L9.

[0131] The first lens L1 to the ninth lens L9 are all made of glass.

[0132] Table 2 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0133]

[0134]

[0135] Table 2

[0136] Table 3 lists the variable spacing values ​​between lens groups of the imaging lens of this embodiment when the object distance changes from 0.3M to infinity.

[0137] Surface number thickness When the object distance is 0.3M Object distance is infinite S7 T0 16.910 4.108 S10 T1 3.996 16.802

[0138] Table 3

[0139] In Example 1, the effective focal length FI of the imaging lens is 41.65 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 is 0.23% to 0.66% when the object distance changes from 0.3m to infinity.

[0140] Combine Figures 1 to 3 As shown in Tables 1 to 3 above, the first embodiment of the present invention is an imaging lens having at least one of the following characteristics: wide object distance (clear focus from 0.3 m to infinity), low distortion (absolute optical distortion ≤ 0.75%), high illumination (relative illumination RI ≥ 70%), miniaturization (total optical length TTL ≤ 79 mm), constant aperture (FNO = 3.0), no defocus at high and low temperatures, and no lens athermalization.

[0141] Example 2

[0142] Figure 4 Schematic diagram of the structure of the imaging lens of Example 2 of the present utility model;

[0143] Figure 5 Schematic diagram of distortion of the imaging lens of Example 2 of the present invention when the object distance is 0.3m;

[0144] Figure 6 Schematic diagram of the distortion of the imaging lens of Example 2 of the present invention when the object distance is infinite.

[0145] In Example 2, 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 meniscus lens with negative optical power, the fifth lens L5 is a meniscus lens with positive optical power, the sixth lens L6 is a meniscus lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a meniscus lens with negative optical power, and the ninth lens L9 is a convex-convex lens with positive optical power.

[0146] The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a doublet, and the seventh lens L7, the eighth lens L8, and the ninth lens L9 form a triplet. A stop STO is provided behind the object-side surface of the ninth lens L9.

[0147] The first lens L1 to the ninth lens L9 are all made of glass.

[0148] Table 4 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0149] Surface serial number Surface type Curvature radius R Thickness d Refractive index Nd Abbe number Vd S1 spherical surface 32.562 2.440 1.883 39.22 S2 spherical surface Infinity 0.500 S3 spherical surface Infinity 0.800 1.581 40.92 S4 spherical surface 17.483 14.390 S5 spherical surface 23.787 4.610 1.593 66.99 S6 spherical surface -17.221 0.700 1.603 38.01 S7 spherical surface -97.862 T0 S8 spherical surface -22.791 3.070 1.946 17.99 S9 spherical surface -15.506 0.700 1.548 45.83 S10 spherical surface 21.439 T1 S11 spherical surface 35.661 2.380 2.001 29.13 S12 spherical surface -37.04 0.700 1.741 27.76 S13 spherical surface 12.52 3.100 1.593 66.99 S14 spherical surface -37.311 0.500 S15(STO) spherical surface Infinity 29.750 S16 spherical surface Infinity 0.900 1.517 64.21 S17 spherical surface Infinity 0.040 S18(IMA) spherical surface Infinity -

[0150] Table 4

[0151] Table 5 lists the variable spacing values ​​between the lens groups of the imaging lens of this embodiment when the object distance changes from 0.3M to infinity.

[0152] Surface number thickness When the object distance is 0.3M Object distance is infinite S7 T0 10.423 4.703 S10 T1 3.998 9.718

[0153] Table 5

[0154] In Example 2, 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.

[0155] Combine Figures 4 to 6 As shown in Tables 1, 4, and 5 above, the second embodiment of the present invention is an imaging lens having at least one of the following characteristics: wide object distance (clear focus from 0.3 m to infinity), low distortion (absolute optical distortion ≤ 0.75%), high illumination (relative illumination RI ≥ 70%), miniaturization (total optical length TTL ≤ 79 mm), constant aperture (FNO = 3.0), no defocus at high and low temperatures, and no lens athermalization.

[0156] Example 3

[0157] Figure 7 This is a schematic structural diagram of an imaging lens according to a third embodiment of the present invention;

[0158] Figure 8 Schematic diagram of distortion of the imaging lens of Example 3 of the present invention when the object distance is 0.3m;

[0159] Figure 9 Schematic diagram of the distortion of the imaging lens of Example 3 of the present invention when the object distance is infinite.

[0160] In Example 3, the first lens L1 is a convex-convex lens with positive optical power, the second lens L2 is a meniscus lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a meniscus lens with negative optical power, the fifth lens L5 is a convex-convex lens with positive optical power, the sixth lens L6 is a meniscus lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a meniscus lens with negative optical power, and the ninth lens L9 is a convex-convex lens with positive optical power.

[0161] The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a doublet, and the seventh lens L7, the eighth lens L8, and the ninth lens L9 form a triplet. A stop STO is provided behind the object-side surface of the ninth lens L9.

[0162] The first lens L1 to the ninth lens L9 are all made of glass.

[0163] Table 6 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0164]

[0165]

[0166] Table 6

[0167] Table 7 lists the variable spacing values ​​between the lens groups of the imaging lens of this embodiment when the object distance changes from 0.3M to infinity.

[0168] Surface number thickness When the object distance is 0.3M Object distance is infinite S7 T0 21.982 4.002 S10 T1 4.018 21.999

[0169] Table 7

[0170] In Example 3, the effective focal length FI of the imaging lens is 40.44 when the object distance is 0.3 m, 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 0.3 m to infinity is -0.24% to -0.63%.

[0171] Combine Figures 7 to 9 As shown in Tables 1, 6, and 7 above, the third embodiment of the present invention is an imaging lens having at least one of the following characteristics: wide object distance (clear focus from 0.3 m to infinity), low distortion (absolute optical distortion ≤ 0.75%), high illumination (relative illumination RI ≥ 70%), miniaturization (total optical length TTL ≤ 79 mm), constant aperture (FNO = 3.0), no defocus at high and low temperatures, and no lens athermalization.

[0172] Example 4

[0173] Figure 10 Schematic diagram of the structure of the imaging lens of Example 4 of the present utility model;

[0174] Figure 11 Schematic diagram of distortion of the imaging lens of Example 4 of the present invention when the object distance is 0.3m;

[0175] Figure 12 Schematic diagram of the distortion of the imaging lens of the fourth embodiment of the present invention when the object distance is infinite.

[0176] In Example 4, the first lens L1 is a convex-convex lens with positive optical power, the second lens L2 is a concave-convex 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-convex lens with negative optical power, the seventh lens L7 is a concave-convex 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.

[0177] The third lens L3 and the fourth lens L4, the fifth lens L5 and the sixth lens L6, the seventh lens L7 and the eighth lens L8 form a doublet lens. A stop STO is provided behind the object-side surface of the ninth lens L9.

[0178] The first lens L1 to the ninth lens L9 are all made of glass.

[0179] Table 8 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0180] Surface serial number Surface type Curvature radius R Thickness d Refractive index Nd Abbe number Vd S1 spherical surface 33.759 2.610 1.883 39.22 S2 spherical surface 314.244 0.650 S3 spherical surface -1259.85 0.700 1.581 40.92 S4 spherical surface 24.806 0.460 S5 spherical surface 29.649 4.040 1.593 66.99 S6 spherical surface -26.057 0.700 1.581 40.92 S7 spherical surface 983.351 T0 S8 spherical surface -116.622 3.880 1.946 17.99 S9 spherical surface -27.389 0.700 1.741 27.76 S10 spherical surface 53.389 T1 S11 spherical surface -11.019 4.000 1.689 31.16 S12 spherical surface 15.368 4.000 1.573 57.52 S13 spherical surface -18.073 0.200 S14 spherical surface 55.738 2.160 1.883 39.22 S15 spherical surface -26.683 0.300 S16(STO) spherical surface Infinity 27.060 S17 spherical surface Infinity 0.900 1.517 64.21 S18 spherical surface Infinity 0.040 S19(IMA) spherical surface Infinity 0

[0181] Table 8

[0182] Table 9 lists the variable spacing values ​​between lens groups of the imaging lens of this embodiment when the object distance changes from 0.3M to infinity.

[0183] Surface number thickness Wide-angle end Telephoto end S7 T0 17.000 4.207 S10 T1 8.262 21.056

[0184] Table 9

[0185] In the fourth embodiment, the effective focal length FI of the imaging lens is 45.78 when the object distance is 0.3 m, 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 0.3 m to infinity is -0.03% to -0.35%.

[0186] Combine Figures 10 to 12 As shown in Tables 1, 8, and 9 above, the fourth embodiment of the present invention is an imaging lens having at least one of the following characteristics: wide object distance (clear focus from 0.3 m to infinity), low distortion (absolute optical distortion ≤ 0.75%), high illumination (relative illumination RI ≥ 70%), miniaturization (total optical length TTL ≤ 79 mm), constant aperture (FNO = 3.0), no defocus at high and low temperatures, and no lens athermalization.

[0187] Example 5

[0188] Figure 13 Schematic diagram of the structure of the imaging lens of Example 5 of the present utility model;

[0189] Figure 14 Schematic diagram of distortion of the imaging lens of Example 5 of the present invention when the object distance is 0.3m;

[0190] Figure 15 Schematic diagram of the distortion of the imaging lens of Example 5 of the present invention when the object distance is infinite.

[0191] In Example 5, the first lens L1 is a convex-plano lens with positive optical power, the second lens L2 is a meniscus lens with negative optical power, the third lens L3 is a convex-convex lens with positive optical power, the fourth lens L4 is a meniscus lens with negative optical power, the fifth lens L5 is a meniscus lens with positive optical power, the sixth lens L6 is a meniscus lens with negative optical power, the seventh lens L7 is a convex-convex lens with positive optical power, the eighth lens L8 is a meniscus lens with negative optical power, and the ninth lens L9 is a convex-convex lens with positive optical power.

[0192] The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a doublet, and the seventh lens L7, the eighth lens L8, and the ninth lens L9 form a triplet. A stop STO is provided behind the object-side surface of the ninth lens L9.

[0193] The first lens L1 to the ninth lens L9 are all made of glass.

[0194] Table 10 lists the relevant parameters of each lens in the imaging lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0195] Surface serial number Surface type Curvature radius R Thickness d Refractive index Nd Abbe number Vd S1 spherical surface 30.883 2.480 1.835 42.73 S2 spherical surface Infinity 4.120 S3 spherical surface -45.701 0.800 1.620 36.35 S4 spherical surface 19.242 9.580 S5 spherical surface 41.868 4.320 1.593 66.99 S6 spherical surface -15.141 0.700 1.517 52.19 S7 spherical surface -44.44 T0 S8 spherical surface -120.516 1.730 1.946 17.99 S9 spherical surface -46.567 0.700 1.581 40.92 S10 spherical surface 28.004 T1 S11 spherical surface 23.408 2.380 2.001 29.13 S12 spherical surface -61.846 0.700 1.699 30.05 S13 spherical surface 9.046 2.830 1.593 66.99 S14 spherical surface 95.514 0.620 S15(STO) spherical surface Infinity 26.750 S16 spherical surface Infinity 0.900 1.517 64.21 S17 spherical surface Infinity 0.040 S18(IMA) spherical surface Infinity 0

[0196] Table 10

[0197] Table 11 lists the variable spacing values ​​between the lens groups of the imaging lens of this embodiment when the object distance changes from 0.3M to infinity.

[0198] Surface number thickness Wide-angle end Telephoto end S7 T0 16.354 4.150 S10 T1 3.998 16.202

[0199] Table 11

[0200] In Example 5, the effective focal length FI of the imaging lens is 41.90 when the object distance is 0.3 m, 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 0.3 m to infinity is -0.18% to -0.61%.

[0201] Combine Figures 13 to 15As shown in Tables 1, 10, and 11 above, the fifth embodiment is an imaging lens having at least one of the following characteristics: wide object distance (clear focus from 0.3 m to infinity), low distortion (absolute optical distortion ≤ 0.75%), high illumination (relative illumination RI ≥ 70%), miniaturization (total optical length TTL ≤ 79 mm), constant aperture (FNO = 3.0), no defocus at high and low temperatures, and no lens athermalization.

[0202] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the utility model disclosed herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the concept of the utility model. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An imaging lens, characterized in that: The lens comprises, in order from the object side to the image side of the optical axis: a first lens group (G1) with positive focal power, a second lens group (G2) with negative focal power, and a third lens group (G3) with positive focal power, wherein the first lens group (G1) and the third lens group are fixed lens groups, and the second lens group (G2) is a focus adjustment group that moves along the optical axis of the imaging lens; The first lens group (G1) comprises, in order: 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, a total of four lenses; the object side surface of the fourth lens (L4) is concave; The second lens group (G2) comprises, in sequence: a fifth lens (L5) with positive optical power and a sixth lens (L6) with negative optical power, a total of two lenses; the sixth lens (L6) is a concave-concave lens; 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, a total of three lenses; the optical powers of the seventh lens (L7) and the eighth lens (L8) are opposite.

2. The imaging lens according to claim 1, wherein: The object side surface of the first lens (L1) is a convex surface, the image side surface of the second lens (L2) is a concave surface, and the third lens (L3) is a convex-convex lens.

3. The imaging lens according to claim 1, wherein: The image-side surface of the fifth lens (L5) is a convex surface.

4. The imaging lens according to claim 1, wherein: The object-side surface of the ninth lens (L9) is a convex surface.

5. The imaging lens according to claim 1, wherein: The third lens (L3) and the fourth lens (L4) form a doublet lens, and the fifth lens (L5) and the sixth lens (L6) form a doublet lens.

6. The imaging lens according to any one of claims 1 to 5, wherein: The effective focal length FG1 of the first lens group (G1) and the total effective focal length FI of the imaging lens when the object distance is 0.3m satisfy the following relationship: 0.8≤FG1 / FI≤1.

7.

7. The imaging lens according to any one of claims 1 to 5, wherein: The effective focal length FG2 of the second lens group (G2) and the total effective focal length FI of the imaging lens when the object distance is 0.3m satisfy the following relationship: -2.4≤FG2 / FI≤-0.

3.

8. The imaging lens according to any one of claims 1 to 5, wherein: The effective focal length FG3 of the third lens group (G3) and the total effective focal length FI of the imaging lens when the object distance is 0.3m satisfy the following relationship: 0.5≤FG3 / FI≤1.

1.

9. The imaging lens according to any one of claims 1 to 5, wherein: The focus shift 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.

10. The imaging lens according to any one of claims 1 to 5, wherein: An air spacing distance d23 between the second lens (L2) and the third lens (L3) on the optical axis and an effective focal length FG1 of the first lens group (G1) satisfy the following relationship: 2.5≤FG1 / d23≤120.

11. The imaging lens according to any one of claims 1 to 5, wherein: 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.

12. The imaging lens according to any one of claims 1 to 5, wherein: 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.

13. The imaging lens according to any one of claims 1 to 5, wherein: 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.

14. The imaging lens according to any one of claims 1 to 5, wherein: 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.

15. The imaging lens according to any one of claims 1 to 5, wherein: 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.

16. The imaging lens according to any one of claims 1 to 5, wherein: 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.

17. The imaging lens according to any one of claims 1 to 5, wherein: 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.

18. The imaging lens according to any one of claims 1 to 5, wherein: The maximum effective light aperture DG1_MAX of the lenses among the first lens (L1) to the ninth lens (L9) and the total effective focal length FI of the imaging lens when the object distance is 0.3m satisfy the following relationship: 4.87≤FI / DG1_MAX≤5.

6.

19. The imaging lens according to any one of claims 1 to 5, wherein: The maximum effective light aperture DG1_MAX of the lenses among 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.

20. The imaging lens according to any one of claims 1 to 5, wherein: 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.

21. The imaging lens according to any one of claims 1 to 5, wherein: The total optical system length TTL of the imaging lens and the total effective focal length FI of the imaging lens when the object distance is 0.3 m satisfy the following relationship: 1.6≤TTL / FI≤2.

22. The imaging lens according to any one of claims 1 to 5, wherein: 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 when the object distance is 0.3m satisfy the following relationship: 0.15≤(Vd6-Vd5) / FI≤0.

75.

23. The imaging lens according to any one of claims 1 to 5, wherein: The total effective focal length FI of the imaging lens when the object distance is 0.3 m 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.

24. The imaging lens according to claim 10, wherein: An air spacing distance d23 between the second lens (L2) and the third lens (L3) on the optical axis and an effective focal length FG1 of the first lens group (G1) satisfy the following relationship: 2.5≤FG1 / d23≤9.

25. The imaging lens according to claim 1, wherein: The imaging lens satisfies 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, 2.6≤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 when the object distance is 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 focus movement distance of the second lens group (G2) within the object distance variation range, d23 is the air separation 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 wherein, 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 lenses 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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