Industrial lens

Abstract

The invention relates to an industrial 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, a fourth lens with negative focal power and a fifth lens with positive focal power; the second lens group comprises a sixth lens with positive focal power and a seventh lens with negative focal power; the third lens group comprises an eighth lens and a ninth lens which are opposite in focal power, a tenth lens with positive focal power and an eleventh lens with negative focal power. The industrial lens has at least one of the characteristics of low distortion, high illumination, high resolution, wide focusing object distance range, no virtual focus in the temperature range of-40 DEG C to + 80 DEG C and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to an industrial lens. 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] With the upgrading and progress of social industrial production, the quality requirements for industrial lenses are gradually increasing. Currently available industrial lenses have the following shortcomings or only meet certain requirements:

[0004] 1. The optical distortion of the lens is large, and there is a large deformation in the four corners of the picture, which affects the resolution of objects;

[0005] 2. Insufficient illumination, dim picture effect, and low color saturation;

[0006] 3. The imaging quality is not high, the picture is blurred, and it interferes with the object resolution;

[0007] 4. The actual shooting object distance range is narrow and cannot meet the use requirements in complex environments;

[0008] 5. The lens is greatly affected by high and low temperature environments, which can easily cause unclear images.

[0009] Therefore, it has become a market development trend to design an industrial lens that meets at least one of the following characteristics: low distortion, high illumination, high resolution, a wide focus distance range, and no out-of-focus in the temperature range of -40°C to +80°C. Summary of the invention

[0010] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an industrial lens having at least one of the characteristics of low distortion, high illumination, high resolution, a wide focus object distance range, and no out-of-focus in the temperature range of -40℃ to +80℃.

[0011] To achieve the above-mentioned object, the present invention provides an industrial lens, which includes, in order from the object side to the image side of the optical axis: 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, 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 industrial 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, a fourth lens with negative optical power and a fifth lens with positive optical power, a total of five lenses;

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

[0014] The third lens group includes, in sequence, an eighth lens, a ninth lens, a tenth lens with positive optical power, and an eleventh lens with negative optical power, a total of four lenses; the optical power of the eighth lens and the ninth lens is opposite.

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

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

[0017] According to a technical solution of the present invention, the eighth lens is a convex-convex lens or a convex-concave lens, the ninth lens is a concave-concave lens or a convex-concave lens, the tenth lens is a convex-convex lens, and the eleventh lens is a concave-concave lens.

[0018] According to a technical solution of the present invention, the third lens, the fourth lens and the fifth lens form a group of triplet lenses, and the sixth lens and the seventh lens form a group of doublet lenses.

[0019] According to a technical solution of the present invention, the eighth lens, the ninth lens, the tenth lens and the eleventh lens are combined into two groups of doublet lenses.

[0020] or the ninth lens, the tenth lens and the eleventh lens are combined into a set of three cemented lenses,

[0021] Alternatively, the eighth lens, the ninth lens, the tenth lens and the eleventh lens are combined into a group of four cemented lenses.

[0022] According to a technical solution of the present invention, the total length TTL of the optical system of the industrial lens and the total effective focal length FI of the industrial lens when the object distance is 0.3 m satisfy the following relationship: 2.0≤TTL / FI≤2.2.

[0023] According to a technical solution of the present invention, the total optical system length TTL of the industrial lens and the back focal length BFL of the industrial lens satisfy the following relationship: 3.1≤TTL / BFL≤3.5.

[0024] 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 industrial lens when the object distance is 0.3 m satisfy the following relationship: 1.0≤FG1 / FI≤1.7.

[0025] 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 industrial lens when the object distance is 0.3m satisfy the following relationship: -2.2≤FG2 / FI≤-0.7.

[0026] 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 industrial lens when the object distance is 0.3 m satisfy the following relationship: 0.7≤FG3 / FI≤1.1.

[0027] According to a technical solution of the present invention, the total effective focal length FI of the industrial lens when the object distance is 0.3m and the total effective focal length FII of the industrial lens when the object distance is infinity satisfy the following relationship: 0.97≤FI / FII≤1.13.

[0028] 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: 0.6≤F1 / FG1≤1.1.

[0029] According to a technical solution of the present invention, the effective focal length F2 of the second lens and the effective focal length FG1 of the first lens group satisfy the following relationship: -0.9≤F2 / FG1≤-0.19.

[0030] According to a technical solution of the present invention, the effective focal length Fa of the triplet lens composed of the third lens to the fifth lens and the effective focal length FG1 of the first lens group satisfy the following relationship: 0.37≤Fa / FG1≤0.91.

[0031] 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: 0.06≤d23 / FG1≤0.45.

[0032] According to a technical solution of the present invention, the effective focal length F6 of the sixth lens and the effective focal length FG2 of the second lens group satisfy the following relationship: -1.4≤F6 / FG2≤-0.5.

[0033] According to a technical solution of the present invention, the effective focal length F7 of the seventh lens and the effective focal length FG2 of the second lens group satisfy the following relationship: 0.3≤F7 / FG2≤0.7.

[0034] According to a technical solution of the present invention, the focus moving distance value d_G2 of the second lens group within the object distance variation range and the total effective focal length FI of the industrial lens when the object distance is 0.3m satisfy the following relationship: 0.14≤d_G2 / FI≤0.5.

[0035] According to a technical solution of the present invention, the effective focal length F8 of the eighth lens and the effective focal length F9 of the ninth lens satisfy the following relationship: -1.6≤F8 / F9≤-0.5.

[0036] According to a technical solution of the present invention, the effective focal length F10 of the tenth lens and the effective focal length FG3 of the third lens group satisfy the following relationship: 0.2≤F10 / FG3≤0.4.

[0037] According to a technical solution of the present invention, the effective focal length F11 of the eleventh lens and the effective focal length FG3 of the third lens group satisfy the following relationship: -0.6≤F11 / FG3≤-0.3.

[0038] According to a technical solution of the present invention, the effective focal length F8 of the eighth lens, the effective focal length F9 of the ninth lens, the effective focal length F10 of the tenth lens, the effective focal length F11 of the eleventh lens and the effective focal length FG3 of the third lens group satisfy the following relationship: -0.3≤(F8+F9+F10+F11) / FG3≤1.0.

[0039] According to a technical solution of the present invention, the refractive index value Nd3 of the third lens under d light and the central thickness value t3 of the third lens satisfy the following relationship: 0.3≤Nd3 / t3≤0.7.

[0040] According to a technical solution of the present invention, the Abbe number Vd6 of the sixth lens, the Abbe number Vd7 of the seventh lens and the total effective focal length FI of the industrial lens when the object distance is 0.3m satisfy the following relationship: 0.2≤|Vd7-Vd6| / FI≤0.7.

[0041] According to a technical solution of the present invention, the Abbe number Vd10 of the tenth lens, the Abbe number Vd11 of the eleventh lens and the total effective focal length FI of the industrial lens when the object distance is 0.3m satisfy the following relationship: 0.5≤|Vd10-Vd11| / FI≤1.2.

[0042] According to a technical solution of the present invention, the total length TTL of the optical system of the industrial lens and the maximum effective aperture D_max of the lenses from the first lens to the eleventh lens satisfy the following relationship: 4.34≤TTL / D_max≤5.46.

[0043] According to a technical solution of the present invention, the industrial lens satisfies at least one of the following conditions:

[0044] 2.02≤TTL / FI≤2.19,

[0045] 3.14≤TTL / BFL≤3.45,

[0046] 1.10≤FG1 / FI≤1.66,

[0047] -1.98≤FG2 / FI≤-0.86,

[0048] 0.71≤FG3 / FI≤1.09,

[0049] 1.00≤FI / FII≤1.10,

[0050] 0.63≤F1 / FG1≤1.01,

[0051] -0.78≤F2 / FG1≤-0.23,

[0052] 0.40≤Fa / FG1≤0.89,

[0053] 0.06≤d23 / FG1≤0.43,

[0054] -1.32≤F6 / FG2≤-0.58,

[0055] 0.33≤F7 / FG2≤0.63,

[0056] 0.14≤d_G2 / FI≤0.49,

[0057] -1.46≤F8 / F9≤-0.64,

[0058] 0.20≤F10 / FG3≤0.38,

[0059] -0.60≤F11 / FG3≤-0.32,

[0060] -0.19≤(F8+F9+F10+F11) / FG3≤0.90,

[0061] 0.32≤Nd3 / t3≤0.66,

[0062] 0.23≤|Vd7-Vd6| / FI≤0.66,

[0063] 0.56≤|Vd10-Vd11| / FI≤1.09,

[0064] 4.44≤TTL / D_max≤5.35,

[0065] Wherein, TTL is the total length of the optical system of the industrial lens; FI is the focal length of the industrial lens when the object distance is 0.3m; BFL is the back focal length of the industrial lens; FG1 is the focal length of the first lens group; FG2 is the focal length of the second lens group; FG3 is the focal length of the third lens group; FII is the focal length of the industrial lens when the object distance is infinity; F1 is the focal length of the first lens; F2 is the focal length of the second lens; Fa is the focal length of the triplet lens composed of the third lens to the fifth lens; d23 is the air spacing distance between the second lens and the third lens on the optical axis; F6 is the focal length of the sixth lens; F 7 is the focal length of the seventh lens; d_G2 is the focus moving distance of the second lens group within the object distance variation range; F8 is the focal length of the eighth lens; F9 is the focal length of the ninth lens; F10 is the focal length of the tenth lens; F11 is the focal length of the eleventh lens; Nd3 is the refractive index of the third lens under d light; t3 is the center thickness of the third lens; Vd6 is the Abbe number of the sixth lens; Vd7 is the Abbe number of the seventh lens; Vd10 is the Abbe number of the tenth lens; Vd11 is the Abbe number of the eleventh lens; D_max is the maximum effective aperture of the lenses from the first lens to the eleventh lens.

[0066] According to the solution of the present invention, by setting the number and optical focal length of industrial lenses, the ultra-wide-angle lens has at least one of the following beneficial effects: low distortion (absolute value of optical distortion ≤ 1.1%), high illumination (RI ≥ 70%), miniaturization (TTL ≤ 85mm), aperture located at the end of the system, constant aperture (FN0 = 3.0), clear resolution of objects from 0.3m to infinity, no out-of-focus in the temperature range of -40°C to +80°C, and normal operation in various high and low temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0068] Figure 1 It is a structural schematic diagram of an industrial lens according to Embodiment 1 of the present invention;

[0069] Figure 2 Schematic diagram of distortion of the industrial lens of Example 1 of the present invention when the object distance is 0.3m;

[0070] Figure 3Schematic diagram of distortion of the industrial lens of Example 1 of the present invention when the object distance is infinite;

[0071] Figure 4 It is a structural schematic diagram of an industrial lens according to Embodiment 2 of the present invention;

[0072] Figure 5 Schematic diagram of distortion of the industrial lens of Example 2 of the present invention when the object distance is 0.3m;

[0073] Figure 6 Schematic diagram of distortion of the industrial lens of Example 2 of the present invention when the object distance is infinite;

[0074] Figure 7 This is a schematic diagram of the structure of an industrial lens according to Embodiment 3 of the present invention;

[0075] Figure 8 Schematic diagram of distortion of the industrial lens of Example 3 of the present invention when the object distance is 0.3m;

[0076] Fig. 9 Schematic diagram of distortion of the industrial lens of Example 3 of the present invention when the object distance is infinite;

[0077] Fig.10 Schematic diagram of the structure of an industrial lens according to Embodiment 4 of the present invention;

[0078] Fig.11 Schematic diagram of distortion of the industrial lens of Example 4 of the present invention when the object distance is 0.3m;

[0079] Fig.12 Schematic diagram of distortion of the industrial lens of Example 4 of the present invention when the object distance is infinite. DETAILED DESCRIPTION

[0080] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and 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.

[0081] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the first lens.

[0082] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0083] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0084] 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 exclude 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 listed 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.

[0085] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as those commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0086] It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following examples only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can also be made, which all belong to the protection scope of the present application.

[0087] like Figures 1 to 12As shown, an embodiment of the present invention provides an industrial lens, which includes, in sequence along the direction from the object side to the image side of the optical axis: 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, a parallel flat 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 industrial lens.

[0088] Among them, the first lens group G1 is a fixed front group, and its relative position to the image plane is fixed during the change of object distance. The optical focal length of the first lens group G1 is positive, which is beneficial to converge the incident light and reduce the aperture of the rear lens; it is beneficial to correct system aberrations and distortions, while reducing tolerance sensitivity and ensuring the uniformity of the picture.

[0089] The second lens group G2 is a focusing group, and the optical focal length of the second lens group G2 is negative, which can smooth the light trend. At the same time, by moving the position of the second lens group G2 on the optical axis, the lens can be focused at an object distance of 0.3m to infinity, ensuring clear imaging at different object distances.

[0090] The third lens group G3 is a fixed rear group, which is fixed relative to the image plane, and the optical focal length of the third lens group G3 is positive, which can ensure a constant aperture and smooth the emitted light, which is beneficial to reduce astigmatism and field curvature changes during focusing, reduce system sensitivity, and ensure production yield.

[0091] 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 in sequence: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5, a total of five lenses.

[0092] The object side surface of the first lens L1 is convex and has positive optical power, which is conducive to converging incident light and reducing distortion.

[0093] The second lens L2 is a concave lens with negative power, which can smooth the trend of light after passing through the L1 lens. When combined with the first lens L1 with positive power, it is helpful to reduce the generation of spherical aberration.

[0094] The third lens L3 is a convex-convex lens with positive power. It uses a high-refractive material, which can reduce the height of the light and is conducive to miniaturization.

[0095] The fourth lens L4 is a concave-concave lens with negative optical power, and the fifth lens L5 is a convex-convex lens with positive optical power. It can be matched with the third lens L3 to form a positive-negative-positive structure. By adopting suitable lens materials, the system chromatic aberration can be balanced, which is beneficial to improving the imaging quality.

[0096] In the embodiment of the present invention, the third lens L3, the fourth lens L4 and the fifth lens L5 can be combined into a triplet lens, which effectively reduces the tolerance sensitivity of the optical system and improves the production yield.

[0097] 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 sixth lens L6 and a seventh lens L7 in sequence, for a total of two lenses;

[0098] The image side surface of the sixth lens L6 is convex and has positive refractive power. The sixth lens L6 can be made of high refractive index material to collect the outgoing light from the first lens group G1 and control the light trend. At the same time, it is beneficial to reduce the field curvature of the system at different object distances and improve the lens resolution.

[0099] The seventh lens L7 is a concave-concave lens with negative optical power, which is matched with the sixth lens L6 in a positive and negative manner, which is beneficial to correcting spherical aberration, balancing system chromatic aberration, and ensuring imaging performance at different object distances.

[0100] In the embodiment of the present invention, the sixth lens L6 and the seventh lens L7 can cooperate with each other to form a doublet lens group, thereby effectively reducing the tolerance sensitivity of the optical system and improving the production yield.

[0101] In the embodiment of the present invention, the third lens group G3 includes in sequence: an eighth lens L8, a ninth lens L9, a tenth lens L10 and an eleventh lens L11, a total of four lenses.

[0102] The eighth lens L8 and the ninth lens L9 have opposite refractive powers, which can achieve the complementarity of positive spherical aberration and negative spherical aberration, reduce system aberrations, and facilitate clear imaging.

[0103] The tenth lens L10 is a convex-convex lens with positive refractive power, which can effectively balance the astigmatism and distortion introduced by the front group.

[0104] The object side surface of the eleventh lens L11 is concave and has negative optical power. It is cemented with the tenth lens L10 to reduce the chromatic aberration produced by the front lens group and balance the system aberration.

[0105] In the embodiment of the present invention, the eighth lens L8, the ninth lens L9, the tenth lens L10 and the eleventh lens L11 can be combined into a group of four cemented lenses, or a single lens and a group of three cemented lenses, or two groups of doublet lenses, which can effectively balance the system chromatic aberration, reduce tolerance sensitivity, and ensure the imaging quality at different object distances under a constant aperture.

[0106] The present invention can keep the aperture of the lens constant during the process of changing the object distance from 0.3m to infinity, so that the image quality is stable and the use requirements of various scenes are met.

[0107] The lens of the present invention adopts three lens groups of fixed, focusing and fixed, and at the same time is a combination of positive, negative and positive optical focal lengths, which is conducive to correcting field curvature and distortion at different object distances from 0.3m to infinity, eliminating system chromatic aberration, reducing tolerance sensitivity, and ensuring clear imaging pictures at different object distances.

[0108] In some embodiments of the present invention, the first lens L1 to the eleventh lens L11 are all made of glass lens material, and all lens lenses are made of glass material, which reduces the lens size, refractive index, and surface shape caused by temperature changes in high and low temperature environments, improves system stability, and is conducive to achieving athermalization, so that the lens is not out of focus in the temperature range of -40°C to 80°C, and the imaging picture is guaranteed to be clear. At the same time, the glass material can better correct the system chromatic aberration and ensure the quality of the lens.

[0109] In some embodiments of the present invention, the total optical system length TTL of the industrial lens and the total effective focal length FI of the industrial lens when the object distance is 0.3m satisfy the following relationship: 2.0≤TTL / FI≤2.2, preferably, 2.02≤TTL / FI≤2.19. Under a certain system focal length value, by controlling the total optical length of the system, the total optical length of the system is reduced, which is conducive to miniaturization.

[0110] In some embodiments of the present invention, the total optical system length TTL of the industrial lens and the back focal length of the industrial lens (i.e., the axial distance from the image side of the last lens to the imaging surface) BFL satisfy the following relationship: 3.1≤TTL / BFL≤3.5, preferably, 3.14≤TTL / BFL≤3.45. On the basis of achieving miniaturization, by controlling the optical back focal length of the 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 industrial lenses, avoids interference, and improves the assembly yield of industrial lenses.

[0111] 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 industrial lens when the object distance is 0.3m satisfy the following relationship: 1.0≤FG1 / FI≤1.7, preferably, 1.10≤FG1 / FI≤1.66. Reasonable control of the ratio of the effective focal length of the first lens group G1 to the effective focal length of the optical system when the object distance is 0.3m is conducive to converging the incident light into the optical system, effectively controlling the light trend, correcting the system aberration distortion, reducing the tolerance sensitivity, and improving the imaging quality of the lens.

[0112] 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 industrial lens when the object distance is 0.3m satisfy the following relationship: -2.2≤FG2 / FI≤-0.7, preferably, -1.98≤FG2 / FI≤-0.86. The effective focal length ratio of the second lens group G2 to the effective focal length of the optical system when the object distance is 0.3m is reasonably controlled to achieve the focusing of the lens at an object distance of 0.3m to infinity, and to ensure clear imaging at different object distances.

[0113] 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 industrial lens when the object distance is 0.3m satisfy the following relationship: 0.7≤FG3 / FI≤1.1, preferably, 0.71≤FG3 / FI≤1.09. Reasonably controlling the effective focal length ratio of the third lens group G3 to the effective focal length ratio of the optical system when the object distance is 0.3m, smoothing the emitted light, and making the light smoothly transition to the image plane is conducive to reducing the astigmatism and field curvature aberration on the image plane, improving the image quality, and effectively compensating the axial chromatic aberration of the front end group to ensure the image quality.

[0114] In some embodiments of the present invention, the total effective focal length FI of the industrial lens when the object distance is 0.3m and the total effective focal length FII of the industrial lens when the object distance is infinity satisfy the following relationship: 0.97≤FI / FII≤1.13, preferably, 1.00≤FI / FII≤1.10. Reasonable control of the ratio of the effective focal length of the optical system when the object distance is 0.3m and infinity can effectively reduce the influence of the lens on the imaging picture when the object distance changes, and meet the requirements of a larger range of working distances.

[0115] 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: 0.6≤F1 / FG1≤1.1, preferably, 0.63≤F1 / FG1≤1.01. Reasonable control of the ratio of the effective focal length of the first lens L1 to the effective focal length of the first lens group G1 is conducive to converging incident light and reducing distortion.

[0116] In some embodiments of the present invention, the effective focal length F2 of the second lens L2 and the effective focal length FG1 of the first lens group G1 satisfy the following relationship: -0.9≤F2 / FG1≤-0.19, preferably, -0.78≤F2 / FG1≤-0.23. By properly controlling the ratio of the effective focal length of the second lens L2 to the effective focal length of the first lens group G1, the trend of light passing through the first lens L1 is smoothed, and the first lens L1 is matched with the positive lens to reduce the generation of spherical aberration.

[0117] In some embodiments of the present invention, the effective focal length Fa of the triplet lens composed of the third lens L3 to the fifth lens L5 and the effective focal length FG1 of the first lens group G1 satisfy the following relationship: 0.37≤Fa / FG1≤0.91, preferably, 0.40≤Fa / FG1≤0.89. Reasonable control of the ratio of the effective focal length of the triplet lens in the first lens group G1 to the effective focal length of the first lens group G1 can effectively reduce system chromatic aberration and effectively balance system spherical aberration, improve resolution; at the same time, it can reduce the tolerance sensitivity between lenses, which is conducive to improving production yield.

[0118] In some embodiments of the present invention, the air distance d23 between the second lens L2 and the third lens L3 on the optical axis and the effective focal length FG1 of the first lens group G1 satisfy the following relationship: 0.06≤d23 / FG1≤0.45, preferably, 0.06≤d23 / FG1≤0.43. Reasonable control of the air distance between the second lens L2 and the third lens L3 on the optical axis in the first lens group can effectively control the trend of light, reduce the deflection angle of light entering the object side of the third lens L3, help reduce the energy loss of light, improve illumination, and reduce the tolerance sensitivity of the third lens L3, which is conducive to improving production yield.

[0119] In some embodiments of the present invention, the effective focal length F6 of the sixth lens L6 and the effective focal length FG2 of the second lens group G2 satisfy the following relationship: -1.4≤F6 / FG2≤-0.5, preferably, -1.32≤F6 / FG2≤-0.58. Reasonably controlling the ratio of the effective focal length of the sixth lens L6 to the effective focal length of the second lens group G2 collects the outgoing light of the first lens group G1, controls the light trend, is conducive to high illumination, and is also conducive to reducing the field curvature of the system at different object distances and improving the lens resolution.

[0120] In some embodiments of the present invention, the effective focal length F7 of the seventh lens L7 and the effective focal length FG2 of the second lens group G2 satisfy the following relationship: 0.3≤F7 / FG2≤0.7, preferably, 0.33≤F7 / FG2≤0.63. Reasonable control of the ratio of the effective focal length of the seventh lens L7 to the effective focal length of the second lens group G2 is conducive to correcting the spherical aberration generated by the sixth lens L6, balancing the system chromatic aberration, and ensuring the imaging performance at different object distances.

[0121] In some embodiments of the present invention, the focus moving distance value d_G2 of the second lens group G2 within the object distance variation range and the total effective focal length FI of the industrial lens when the object distance is 0.3m satisfy the following relationship: 0.14≤d_G2 / FI≤0.5, preferably, 0.14≤d_G2 / FI≤0.49. Reasonably controlling the focus moving distance of the second lens group G2 within the object distance variation range and the effective focal length ratio of the optical system when the object distance is 0.3m ensures that the focus moving distance is within a certain range, which is beneficial to the stability of the system during the focusing process, improves the focusing response speed of the lens, and ensures the imaging quality at different object distances.

[0122] In some embodiments of the present invention, 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: -1.6≤F8 / F9≤-0.5, preferably, -1.46≤F8 / F9≤-0.64. The ratio of the effective focal length of the eighth lens L8 to the effective focal length of the ninth lens L9 is reasonably controlled, and the ratio is always kept negative, that is, the effective focal lengths of the eighth lens L8 and the ninth lens L9 are opposite in positive and negative, which can achieve the complementarity of positive spherical aberration and negative spherical aberration, reduce system aberrations, and facilitate clear imaging.

[0123] In some embodiments of the present invention, the effective focal length F10 of the tenth lens L10 and the effective focal length FG3 of the third lens group G3 satisfy the following relationship: 0.2≤F10 / FG3≤0.4, preferably, 0.20≤F10 / FG3≤0.38. Reasonable control of the ratio of the effective focal length of the tenth lens L10 to the effective focal length of the third lens group G3 can effectively balance the astigmatism and distortion introduced by the front group, reduce the field curvature on the image plane, and help improve the image quality.

[0124] In some embodiments of the present invention, the effective focal length F11 of the eleventh lens L11 and the effective focal length FG3 of the third lens group G3 satisfy the following relationship: -0.6≤F11 / FG3≤-0.3, preferably, -0.60≤F11 / FG3≤-0.32. Reasonable control of the ratio of the effective focal length of the eleventh lens L11 to the effective focal length of the third lens group G3 is conducive to balancing the chromatic aberration generated by the tenth lens L10 positive lens and reducing system aberrations.

[0125] In some embodiments of the present invention, the effective focal length F8 of the eighth lens L8, the effective focal length F9 of the ninth lens L9, the effective focal length F10 of the tenth lens L10 and the effective focal length F11 of the eleventh lens L11 and the effective focal length FG3 of the third lens group G3 satisfy the following relationship: -0.3≤(F8+F9+F10+F11) / FG3≤1.0, preferably, -0.19≤(F8+F9+F10+F11) / FG3≤0.90. Reasonable setting of the optical power of the eighth lens L8, the ninth lens L9, the tenth lens L10 and the eleventh lens L11 is conducive to the mutual compensation of positive and negative spherical aberrations, while correcting the astigmatism and field curvature of the system, and improving the resolution of the lens; at the same time, the trend of light is effectively controlled to make the light transition smoothly, effectively reduce the tolerance sensitivity of the fixed rear group, and improve the production yield.

[0126] In some embodiments of the present invention, the refractive index value Nd3 of the third lens L3 under d light and the central thickness value t3 of the third lens L3 satisfy the following relationship: 0.3≤Nd3 / t3≤0.7, preferably, 0.32≤Nd3 / t3≤0.66. Reasonably controlling the ratio of the refractive index of the third lens L3 to the central thickness of the third lens L3 ensures that the third lens L3 has a larger refractive index value, gathers the emitted light of the second lens L2, and is conducive to ensuring that the optical system is insensitive within the range of ambient temperature changes and object distance changes, realizing lens athermalization, and being suitable for high and low temperature environments.

[0127] In some embodiments of the present invention, the Abbe number Vd6 of the sixth lens L6 and the Abbe number Vd7 of the seventh lens L7 satisfy the following relationship with the total effective focal length FI of the industrial lens when the object distance is 0.3m: 0.2≤|Vd7-Vd6| / FI≤0.7, preferably, 0.23≤|Vd7-Vd6| / FI≤0.66. Reasonably controlling the ratio of the difference in the Abbe numbers of the seventh lens L7 and the sixth lens L6 to the effective focal length of the optical system when the object distance is 0.3m, and using materials with different dispersion coefficients, the dispersion can be compensated for each other, so as to achieve the purpose of eliminating position 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.

[0128] In some embodiments of the present invention, the Abbe number Vd10 of the tenth lens L10 and the Abbe number Vd11 of the eleventh lens L11 satisfy the following relationship with the total effective focal length FI of the industrial lens when the object distance is 0.3m: 0.5≤|Vd10-Vd11| / FI≤1.2, preferably, 0.56≤|Vd10-Vd11| / FI≤1.09. Reasonably controlling the ratio of the difference in the Abbe numbers of the tenth lens L10 and the eleventh lens L11 to the effective focal length of the optical system when the object distance is 0.3m and using materials with different chromatic aberration coefficients is conducive to reducing the chromatic aberration generated by the front lens group and balancing the system aberration.

[0129] In some embodiments of the present invention, the total length TTL of the optical system of the industrial lens and the maximum effective aperture D_max of the lenses in the first lens L1 to the eleventh lens L11 satisfy the following relationship: 4.34≤TTL / D_max≤5.46, preferably, 4.44≤TTL / D_max≤5.35. By reasonably setting the ratio of the total length of the optical system to the maximum effective aperture in the first to the eleventh lenses, the maximum effective aperture and the total length of the optical system can be reasonably constrained and controlled, which is conducive to miniaturization of the lens.

[0130] Four groups of specific implementations are given below based on the above-mentioned configuration of the present invention to specifically illustrate the industrial lens according to the present invention. The industrial lens according to the present invention has a total of eleven lenses, and each cemented surface of the cemented lens is recorded as a surface, plus the aperture STO, the protective glass CG and the image surface IMA, a total of 20 or 21 surfaces. Among them, the aperture STO is arranged behind the image side surface of the eleventh lens L11. For the convenience of description, each lens surface, the aperture STO and the protective glass CG are numbered as S1, S2 to S20 or S1, S2 to S21.

[0131] Four sets of example data are shown in Table 1 below:

[0132]

[0133]

[0134] Table 1

[0135] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0136] Embodiment 1

[0137] Figure 1 It is a structural schematic diagram of an industrial lens according to Embodiment 1 of the present invention;

[0138] Figure 2 Schematic diagram of distortion of the industrial lens of Example 1 of the present invention when the object distance is 0.3m;

[0139] Figure 3 Schematic diagram of distortion of the industrial lens of Example 1 of the present invention when the object distance is infinite.

[0140] In Embodiment 1, 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-concave lens with negative optical power, the fifth lens L5 is a convex-convex lens with positive optical power, the sixth lens L6 is a convex-convex lens with positive 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, the ninth lens L9 is a concave-concave lens with negative optical power, the tenth lens L10 is a convex-convex lens with positive optical power, and the eleventh lens L11 is a concave-concave lens with negative optical power.

[0141] The third lens L3, the fourth lens L4 and the fifth lens L5 form a triplet lens, the sixth lens L6 and the seventh lens L7 form a doublet lens, the eighth lens L8, the ninth lens L9, the tenth lens L10 and the eleventh lens L11 form a quadruple lens. A stop STO is disposed behind the image side surface of the eleventh lens L11.

[0142] Table 2 lists the relevant parameters of each lens in the industrial lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0143]

[0144]

[0145] Table 2

[0146] Table 3 lists the variable spacing values ​​between lens groups of the industrial lens of this embodiment when the object distance changes from 0.3M to infinity.

[0147] Surface number thickness When the object distance is 0.3M Object distance is infinite S8 T0 21.994 4.000 S11 T1 4.006 22.000

[0148] Table 3

[0149] In the first embodiment, the effective focal length FI of the industrial lens is 40.96 when the object distance is 0.3 m, the effective focal length FII is 38.01 when the object distance is infinite, the aperture FNO is 3.0, the optical distortion is -0.54% to -1.07%, and the relative illumination is 70%.

[0150] Combination Figures 1 to 3 As shown in Tables 1 to 3 above, the first embodiment of the present invention is an industrial lens having at least one of the following characteristics: low distortion (absolute value of optical distortion ≤ 1.1%), high illumination (RI ≥ 70%), miniaturization (TTL ≤ 85 mm), aperture located at the end of the system, constant aperture (FN0 = 3.0), clear resolution of object distances from 0.3 m to infinity, no out-of-focus in the temperature range of -40°C to +80°C, and normal operation in various high and low temperature environments.

[0151] Embodiment 2

[0152] Figure 4 It is a structural schematic diagram of an industrial lens according to Embodiment 2 of the present invention;

[0153] Figure 5 Schematic diagram of distortion of the industrial lens of Example 2 of the present invention when the object distance is 0.3m;

[0154] Figure 6 Schematic diagram of distortion of the industrial lens of Example 2 of the present invention when the object distance is infinite.

[0155] In the second embodiment, 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-concave 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-convex lens with positive 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, the ninth lens L9 is a concave-concave lens with negative optical power, the tenth lens L10 is a convex-convex lens with positive optical power, and the eleventh lens L11 is a concave-concave lens with negative optical power.

[0156] The third lens L3, the fourth lens L4 and the fifth lens L5 form a triplet lens, the sixth lens L6 and the seventh lens L7 form a doublet lens, the eighth lens L8, the ninth lens L9, the tenth lens L10 and the eleventh lens L11 form a quadruple lens. A stop STO is disposed behind the image side surface of the eleventh lens L11.

[0157] Table 4 lists the relevant parameters of each lens in the industrial lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0158] Surface serial number Surface type Curvature radius R Thickness d Refractive index Nd Abbe number Vd S1 Spherical 41.165 2.380 1.871 40.73 S2 Spherical -859.303 0.902 S3 Spherical -68.723 0.800 1.648 33.89 S4 Spherical 32.891 17.736 S5 Spherical 36.191 3.024 1.834 37.32 S6 Spherical -65.105 0.700 1.654 39.54 S7 Spherical 13.633 4.248 1.593 68.34 S8 Spherical -129.610 T0 S9 Spherical -61.007 3.944 1.946 17.94 S10 Spherical -26.719 0.700 1.567 42.81 S11 Spherical 22.513 T1 S12 Spherical 21.905 2.863 2.001 25.47 S13 Spherical -25.963 0.700 1.673 32.17 S14 Spherical 8.461 3.720 1.593 66.99 S15 Spherical -15.944 0.700 1.855 25.15 S16 Spherical 173.198 0.400 S17(STO) Spherical Infinity 25.184 S18 Spherical Infinity 0.900 1.517 64.20 S19 Spherical Infinity 0.100 S20(IMA) Spherical Infinity 0.000

[0159] Table 4

[0160] Table 5 lists the variable spacing values ​​between lens groups of the industrial lens of this embodiment when the object distance changes from 0.3M to infinity.

[0161] Surface number thickness Wide-angle end Telephoto end S8 T0 11.994 3.998 S11 T1 4.006 12.002

[0162] Table 5

[0163] In the second embodiment, the effective focal length FI of the industrial lens is 40.76 when the object distance is 0.3m, the effective focal length FII is 38.24 when the object distance is infinite, the aperture FNO is 3.0, the optical distortion is -0.24% to -0.75%, and the relative illumination is 73%.

[0164] Combination Figures 4 to 6 As shown in Tables 1, 4 and 5 above, the second embodiment is an industrial lens having at least one of the following characteristics: low distortion (absolute value of optical distortion ≤ 1.1%), high illumination (RI ≥ 70%), miniaturization (TTL ≤ 85 mm), aperture located at the end of the system, constant aperture (FN0 = 3.0), clear resolution of object distances from 0.3 m to infinity, no defocusing in the temperature range of -40°C to +80°C, and normal operation in various high and low temperature environments.

[0165] Embodiment 3

[0166] Figure 7 This is a schematic diagram of the structure of an industrial lens according to Embodiment 3 of the present invention;

[0167] Figure 8 Schematic diagram of distortion of the industrial lens of Example 3 of the present invention when the object distance is 0.3m;

[0168] Fig. 9 Schematic diagram of distortion of the industrial lens of Example 3 of the present invention when the object distance is infinite.

[0169] In embodiment 3, 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-concave lens with negative optical power, the fifth lens L5 is a convex-convex lens with positive optical power, the sixth lens L6 is a convex-convex lens with positive 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, the ninth lens L9 is a concave-concave lens with negative optical power, the tenth lens L10 is a convex-convex lens with positive optical power, and the eleventh lens L11 is a concave-concave lens with negative optical power.

[0170] The third lens L3, the fourth lens L4 and the fifth lens L5 form a triplet lens, the sixth lens L6 and the seventh lens L7 form a doublet lens, the ninth lens L9, the tenth lens L10 and the eleventh lens L11 form a triplet lens. The aperture STO is arranged behind the image side surface of the eleventh lens L11.

[0171] Table 6 lists the relevant parameters of each lens in the industrial lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0172]

[0173]

[0174] Table 6

[0175] Table 7 lists the variable spacing values ​​between lens groups of the industrial lens of this embodiment when the object distance changes from 0.3M to infinity.

[0176] Surface number thickness Wide angle Telephoto end S8 T0 14.139 2.000 S11 T1 8.287 20.426

[0177] Table 7

[0178] In the third embodiment, the effective focal length FI of the industrial lens is 39.08 when the object distance is 0.3 m, the effective focal length FII is 36.52 when the object distance is infinite, the aperture FNO is 3.0, the optical distortion is -0.58% to -1.00%, and the relative illumination is 75%.

[0179] Combination Figures 7 to 9 As shown in Table 1, Table 6 and Table 7 above, the third embodiment is an industrial lens having at least one of the following characteristics: low distortion (absolute value of optical distortion ≤ 1.1%), high illumination (RI ≥ 70%), miniaturization (TTL ≤ 85 mm), aperture located at the end of the system, constant aperture (FN0 = 3.0), clear resolution from 0.3 m to infinity object distance, no out-of-focus in the temperature range of -40 ° C to + 80 ° C, and normal operation in various high and low temperature environments.

[0180] Embodiment 4

[0181] Fig.10 Schematic diagram of the structure of an industrial lens according to Embodiment 4 of the present invention;

[0182] Fig.11 Schematic diagram of distortion of the industrial lens of Example 4 of the present invention when the object distance is 0.3m;

[0183] Fig.12 Schematic diagram of distortion of the industrial lens of Example 4 of the present invention when the object distance is infinite.

[0184] In embodiment 4, 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-concave lens with negative optical power, the fifth lens L5 is a convex-convex lens with positive optical power, the sixth lens L6 is a convex-convex lens with positive 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 negative optical power, the ninth lens L9 is a convex-convex lens with positive optical power, the tenth lens L10 is a convex-convex lens with positive optical power, and the eleventh lens L11 is a concave-concave lens with negative optical power.

[0185] The third lens L3, the fourth lens L4 and the fifth lens L5 form a triplet lens, the sixth lens L6 and the seventh lens L7 form a doublet lens, the eighth lens L8 and the ninth lens L9 form a doublet lens, the tenth lens L10 and the eleventh lens L11 form a doublet lens. The aperture stop STO is arranged behind the image side surface of the eleventh lens L11.

[0186] Table 8 lists the relevant parameters of each lens in the industrial lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0187]

[0188]

[0189] Table 8

[0190] Table 9 lists the variable spacing values ​​between lens groups of the industrial lens of this embodiment when the object distance changes from 0.3M to infinity.

[0191] Surface number thickness Wide-angle end Telephoto end S8 T0 11.517 2.000 S11 T1 2.083 11.600

[0192] Table 9

[0193] In the fourth embodiment, the effective focal length FI of the industrial lens is 39.72 when the object distance is 0.3 m, the effective focal length FII is 38.79 when the object distance is infinite, the aperture FNO is 3.0, the optical distortion is -0.48% to -0.77%, and the relative illumination is 73%.

[0194] Combination Figures 10 to 12As shown in Table 1, Table 8 and Table 9 above, the fourth embodiment of the present invention is an industrial lens having at least one of the following characteristics: low distortion (absolute value of optical distortion ≤ 1.1%), high illumination (RI ≥ 70%), miniaturization (TTL ≤ 85 mm), aperture located at the end of the system, constant aperture (FN0 = 3.0), clear resolution of object distances from 0.3 m to infinity, no defocusing in the temperature range of -40 ° C to + 80 ° C, and normal operation in various high and low temperature environments.

[0195] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

Claims

1. An industrial lens, characterized in that: The optical lens comprises, in sequence 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 industrial 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, a fourth lens (L4) with negative optical power and a fifth lens (L5) with positive optical power, a total of five lenses; The second lens group (G2) includes in sequence: a sixth lens (L6) with positive optical power and a seventh lens (L7) with negative optical power, a total of two lenses; The third lens group (G3) includes, in sequence: an eighth lens (L8), a ninth lens (L9), a tenth lens (L9) with positive focal power, and an eleventh lens (L11) with negative focal power, a total of four lenses; the eighth lens (L8) and the ninth lens (L9) have opposite focal powers.

2. The industrial lens according to claim 1, characterized in that: The object side surface of the first lens (L1) is a convex surface, the second lens (L2) is a concave-concave lens, the third lens (L3) is a convex-convex lens; the fourth lens (L4) is a concave-concave lens, and the fifth lens (L5) is a convex-convex lens.

3. The industrial lens according to claim 1, characterized in that: The image side surface of the sixth lens (L6) is a convex surface; and the seventh lens (L7) is a concave-concave lens.

4. The industrial lens according to claim 1, characterized in that: The eighth lens (L8) is a convex-convex lens or a convex-concave lens, the ninth lens (L9) is a concave-concave lens or a convex-concave lens, the tenth lens (L10) is a convex-convex lens, and the eleventh lens (L11) is a concave-concave lens.

5. The industrial lens according to claim 1, characterized in that: The third lens (L3), the fourth lens (L4) and the fifth lens (L5) form a group of triplet lenses, and the sixth lens (L6) and the seventh lens (L7) form a group of doublet lenses.

6. The industrial lens according to claim 1, characterized in that: The eighth lens (L8), the ninth lens (L9), the tenth lens (L10) and the eleventh lens (L11) are combined into two groups of doublet lenses; Or the ninth lens (L9), the tenth lens (L10) and the eleventh lens (L11) are combined into a set of triplet lenses; Alternatively, the eighth lens (L8), the ninth lens (L9), the tenth lens (L10) and the eleventh lens (L11) are combined into a group of four cemented lenses.

7. The industrial lens according to any one of claims 1 to 6, characterized in that: The total length TTL of the optical system of the industrial lens and the total effective focal length FI of the industrial lens when the object distance is 0.3 m satisfy the following relationship: 2.0≤TTL / FI≤2.

2.

8. The industrial lens according to any one of claims 1 to 6, characterized in that: The total length TTL of the optical system of the industrial lens and the back focal length BFL of the industrial lens satisfy the following relationship: 3.1≤TTL / BFL≤3.

5.

9. The industrial lens according to any one of claims 1 to 6, characterized in that: The effective focal length FG1 of the first lens group (G1) and the total effective focal length FI of the industrial lens when the object distance is 0.3m satisfy the following relationship: 1.0≤FG1 / FI≤1.

7.

10. The industrial lens according to any one of claims 1 to 6, characterized in that: The effective focal length FG2 of the second lens group (G2) and the total effective focal length FI of the industrial lens when the object distance is 0.3 m satisfy the following relationship: -2.2≤FG2 / FI≤-0.7.

Images