Industrial lens

Abstract

The industrial lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from an object side to an image side along an optical axis, the first to sixth lenses form a focusing lens group, and the seventh lens is a fixed lens group. The fourth lens and the fifth lens are glued to form a glued lens; the total length TTL of the industrial lens and the focal length EFL of the industrial lens meet the condition that TTL / EFL is greater than or equal to 2.9600 and less than or equal to 2.9900; the total length TTL of the industrial lens and the maximum effective aperture DM of the lens in the industrial lens meet the following condition: TTL / DM is more than or equal to 2.5500 and less than or equal to 2.7800; the image plane size IM of the industrial lens and the working F number of the industrial lens meet the condition that IM / FNO is more than or equal to 3.1900 and less than or equal to 3.2000; and the field angle FOV of the industrial lens is greater than or equal to 30.2100. Therefore, the lens can realize high-resolution focusing imaging at the object distance of 100mm to 1000mm, the design of a low-distortion, large-aperture and high-resolution industrial lens can be considered at the optimal object distance, the focal length is 16mm, the maximum aperture is F2.8, the optimal object distance is 400mm, the maximum optical distortion is less than 0.20%, and the imaging quality can reach 200pl / mmgt; and the MTF is 0.45.

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 have important applications in precision measurement and inspection. Their high resolution and low distortion enable them to accurately capture changes in tiny objects. In the manufacturing industry, they are widely used in automated assembly and quality inspection processes to ensure consistent product quality. In medical equipment, they are often used in microscopes, endoscopes, and other devices, facilitating accurate diagnosis.

[0003] As the market demands for lower distortion and larger apertures in industrial lenses, and higher resolution requirements in the edge field of view, distortion and field curvature in the edge field of view have become difficult problems that must be solved by industrial lenses. Resolution consistency at different object distances is an even more difficult problem to solve. Summary of the Invention

[0004] The present invention provides an industrial lens that adopts a structure that combines seven spherical and aspherical lenses. By matching lens materials and rationally allocating the optical power of each component, and adopting a front-group focusing method, it has obvious cost advantages and achieves high-resolution focused imaging at object distances of 100mm to 1000mm. At the optimal object distance, the industrial lens design can take into account low distortion and large aperture, high resolution, with a focal length of 16mm, a maximum aperture of F2.8, an optimal object distance of 400mm, a maximum optical distortion of less than 0.20%, and an imaging quality of 200pl / mm > 0.45MTF.

[0005] According to the present invention, an industrial lens is provided, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, arranged in sequence along an optical axis from the object side to the image side; the first to sixth lenses form a focusing lens group, the seventh lens is a fixed lens group; the fourth lens and the fifth lens are cemented together to form a cemented lens;

[0006] The total length TTL of the industrial lens and the focal length EFL of the industrial lens satisfy the following relationship: 2.9600≤TTL / EFL≤2.9900;

[0007] The total length TTL of the industrial lens and the maximum effective aperture DM of the lens in the industrial lens satisfy the following relationship: 2.5500≤TTL / DM≤2.7800;

[0008] The image plane size IM of the industrial lens and the working F number of the industrial lens satisfy the following relationship: 3.1900≤IM / FNO≤3.2000;

[0009] The field of view (FOV) of the industrial lens satisfies: FOV ≥ 30.2100.

[0010] Optionally, the first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has optical power, the fifth lens has optical power, the sixth lens has positive optical power, and the seventh lens has positive optical power.

[0011] Optionally, the object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is concave, and the image-side surface is convex; the object-side surface of the third lens is convex, and the image-side surface is concave; the object-side surface of the fourth lens is concave, and the image-side surface is convex; the object-side surface of the fifth lens is concave, and the image-side surface is convex; the object-side surface of the sixth lens is convex, and the image-side surface is either concave or convex; and the object-side surface of the seventh lens is convex, and the image-side surface is concave;

[0012] Among them, when the mirror surface of each lens is convex, it is convex toward the object side; when the mirror surface is concave, it is convex toward the image side; when the mirror surface is convex, it is convex toward the image side; when the mirror surface is concave, it is convex toward the object side.

[0013] Optionally, the first lens, the third lens, and the sixth lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens, and the seventh lens are plastic aspherical lenses.

[0014] Optionally, the refractive index ND1 of the first lens is ≥1.74.

[0015] Optionally, the Abbe number VD4 of the fourth lens and the Abbe number VD5 of the fifth lens satisfy: VD5 / VD4≥2.3700.

[0016] Optionally, the optical power ΦZ1 of the focusing lens group and the optical power ΦZ2 of the fixed lens group satisfy the following relationship: 8.5800≤ΦZ1 / ΦZ2≤23.9200.

[0017] Optionally, the optical power Φ23 of the second to third lenses and the optical power Φ47 of the fourth to seventh lenses satisfy the following relationship: 0.9000≤Φ23 / Φ47≤1.0700.

[0018] Optionally, a shape factor ξ2 of the second lens satisfies: 8.810≤|ξ2|≤19.110.

[0019] Optionally, a minimum value RI.MIN of the full-field relative illumination of the industrial lens satisfies: RI.MIN≥89.50%.

[0020] The technical solution of the embodiment of the present invention includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the optical axis from the object side to the image side; the first lens to the sixth lens form a focusing lens group, and the seventh lens is a fixed lens group; the fourth lens and the fifth lens are cemented to form a cemented lens; the total length TTL of the industrial lens and the focal length EFL of the industrial lens satisfy the following relationship: 2.9600≤TTL / EFL≤2.9900; the total length TTL of the industrial lens and the maximum effective aperture DM of the lens in the industrial lens satisfy the following relationship: 2.5500≤TTL / DM≤2.7800; the image plane size IM of the industrial lens and the working F number of the industrial lens satisfy the following relationship: 3.1900≤IM / FNO≤3.2000; the field of view FOV of the industrial lens satisfies the following relationship: FOV≥30.2100. Therefore, a structure of seven spherical and aspherical lenses is adopted. Through the combination of lens materials and the reasonable distribution of the optical focal length of each component, the front group focusing method is adopted, which has obvious cost advantages and realizes high-resolution focused imaging at object distances of 100mm to 1000mm. At the optimal object distance, it can take into account low distortion, large aperture and high-resolution industrial lens design. The focal length is 16mm, the maximum aperture is F2.8, the optimal object distance is 400mm, the |maximum optical distortion| is less than 0.20%, and the imaging quality can reach 200pl / mm>0.45MTF.

[0021] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 1 is a schematic structural diagram of an industrial lens provided in Embodiment 1 of the present invention;

[0024] Figure 2 This is a ray fan diagram of an industrial lens provided in Example 1 of the present invention;

[0025] Figure 3 This is a field curvature distortion diagram of the industrial lens provided in Example 1 of the present invention;

[0026] Figure 4 This is the MTF diagram of the industrial lens at an object distance of 400 mm provided in the first embodiment of the present invention;

[0027] Figure 5 This is the MTF diagram of the industrial lens at an object distance of 100 mm provided in the first embodiment of the present invention;

[0028] Figure 6 This is the MTF diagram of the industrial lens at an object distance of 1000 mm provided in the first embodiment of the present invention;

[0029] Figure 7 Schematic diagram of the structure of the industrial lens provided by the second embodiment of the present invention;

[0030] Figure 8 This is a ray fan diagram of an industrial lens provided in Example 2 of the present invention;

[0031] Figure 9 This is a field curvature distortion diagram of the industrial lens provided by the second embodiment of the present invention;

[0032] Figure 10 This is the MTF diagram of the industrial lens at an object distance of 400mm provided in the second embodiment of the present invention;

[0033] Figure 11 This is the MTF diagram of the industrial lens at an object distance of 100 mm provided in the second embodiment of the present invention;

[0034] Figure 12 This is the MTF diagram of the industrial lens at an object distance of 1000 mm provided in the second embodiment of the present invention;

[0035] Figure 13 Schematic diagram of the structure of the industrial lens provided by the third embodiment of the present invention;

[0036] Figure 14 This is a ray fan diagram of an industrial lens provided in Example 3 of the present invention;

[0037] Figure 15 This is a field curvature distortion diagram of the industrial lens provided in Example 3 of the present invention;

[0038] Figure 16 This is the MTF diagram of the industrial lens at an object distance of 400mm provided in the third embodiment of the present invention;

[0039] Figure 17 This is the MTF diagram of the industrial lens at an object distance of 100 mm provided in the third embodiment of the present invention;

[0040] Figure 18 This is the MTF diagram of the industrial lens provided in Example 3 of the present invention at an object distance of 1000 mm. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar items and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be implemented in sequences other than those illustrated or described herein. Furthermore, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0043] An industrial lens according to an embodiment of the present invention includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in sequence along an optical axis from the object side to the image side; the first to sixth lenses form a focusing lens group, and the seventh lens is a fixed lens group; the fourth lens and the fifth lens are cemented together to form a cemented lens;

[0044] The total length TTL of the industrial lens and the focal length EFL of the industrial lens meet the following requirements: 2.9600 ≤ TTL / EFL ≤ 2.9900;

[0045] The total length TTL of the industrial lens and the maximum effective aperture DM of the lens in the industrial lens meet the following requirements: 2.5500≤TTL / DM≤2.7800;

[0046] The image plane size IM of the industrial lens and the working F number of the industrial lens meet the following requirements: 3.1900≤IM / FNO≤3.2000;

[0047] The field of view (FOV) of the industrial lens meets the following requirements: FOV ≥ 30.2100.

[0048] It is understood that the first, second, third, diaphragm, fourth, fifth, sixth, and seventh lenses can be fixedly mounted within a single lens barrel. The first through sixth lenses form a focusing group for focusing at different object distances, while the seventh lens serves as a fixed group, achieving high resolution at varying object distances. The fourth and fifth lenses are cemented together to reduce the air gap between them, shortening the overall lens length. Furthermore, cemented lenses can be used to minimize or eliminate chromatic aberration, allowing for full correction of various aberrations in industrial lenses. This improves resolution and optimizes optical properties such as distortion while maintaining a compact design. They also reduce light loss caused by inter-lens reflections, increasing illumination and thus improving image quality and clarity. Furthermore, the use of cemented lenses reduces the number of components between the two lenses, simplifying assembly procedures during lens manufacturing, reducing costs, and reducing sensitivity to tolerances such as tilt and deflection that can occur during lens assembly.

[0049] In addition, TTL is the distance from the front end of the first lens to the image plane, and DM is the maximum effective aperture of the first lens in the lens. While ensuring that the image height remains unchanged, the shorter the total length, the smaller the maximum effective aperture, and the corresponding smaller the volume. Meeting the above conditional formula can achieve a large image height while reducing the volume. EFL represents the overall focal length of the lens, and FOV represents the field of view of the lens. IM represents the image plane size of the lens, and FNO represents the working F number of the lens. For the same image plane, the smaller the working F number, the larger the aperture of the lens, the greater the amount of light entering, and the resulting image brightness and clarity are higher. Furthermore, when the total length TTL of the industrial lens, the focal length EFL of the industrial lens, the maximum effective aperture DM of the first lens in the lens, the working F number of the lens, the image plane size IM of the lens, and the field of view angle FOV of the lens meet the aforementioned relationship, the industrial lens can have the characteristics of small size, high brightness, good clarity, and short total length.

[0050] Optionally, the first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has optical power, the fifth lens has optical power, the sixth lens has positive optical power, and the seventh lens has positive optical power.

[0051] It can be understood that the optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger the ability to bend light, and the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is a positive number, the refraction of light is convergent; when the optical power is a negative number, the refraction of light is divergent. The optical power can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0052] Among them, the first lens has a negative optical focal length, which can help more light enter the optical system and ensure that the lens has a larger field of view angle range. When the second lens has a positive optical focal length, it can shrink the light entering the first lens so that the light can be transmitted smoothly backward during the propagation process without excessive deflection, which is beneficial to promoting the improvement of image quality and the realization of a miniaturized lens design, that is, it is beneficial to reduce the aperture and total length of the lens. The third lens has a positive optical focal length, which can shrink the light passing through the aperture so that the light can be transmitted smoothly backward during the propagation process without excessive deflection, which is beneficial to promoting the improvement of image quality and the realization of a miniaturized lens design. The fourth lens has a negative or positive optical focal length. When the fourth lens has a negative optical focal length, it can diverge the light entering the fourth lens, making the light beam divergence angle larger, so that the light reaches the chip on the image side, which is beneficial to expand the imaging range. When the fourth lens has a positive optical power, it can shrink the light entering the fourth lens so that the light can be transmitted backward smoothly during the propagation process without excessive deflection, which is beneficial to promoting the improvement of image quality and reducing the diameter and total length of the lens. The fifth lens has a negative or positive optical power. When the fifth lens has a negative optical power, it can diverge the light entering the fifth lens so that the divergence angle of the light beam is larger, so that the light reaches the chip on the image side, which is beneficial to expanding the imaging range. When the fifth lens has a positive optical power, it can shrink the light entering the fifth lens so that the light can be transmitted backward smoothly during the propagation process without excessive deflection, which is beneficial to promoting the improvement of image quality and reducing the diameter and total length of the lens. The sixth lens has a positive optical power and can shrink the light passing through the aperture so that the light can be transmitted backward smoothly during the propagation process without excessive deflection, which is beneficial to promoting the improvement of image quality and facilitating the realization of a miniaturized lens design. The seventh lens has positive optical power and can shrink light passing through the aperture, allowing it to propagate smoothly backward without significant deflection. This improves image quality and facilitates miniaturized lens design. In one embodiment, the fourth and fifth lenses are cemented together, and the resulting optical power is either positive or negative. The optical power of the fourth and fifth lenses can be appropriately matched to achieve the desired optical power.

[0053] The embodiment of the present invention uses seven lenses and reasonably matches the optical power of each lens to achieve good imaging performance of the optical system, so that it can correct aberrations well and ensure sufficiently good image quality.

[0054] Optionally, the object-side surface of the first lens is convex, and the image-side surface is concave, the object-side surface of the second lens is concave, and the image-side surface is convex, the object-side surface of the third lens is convex, and the image-side surface is concave, the object-side surface of the fourth lens is concave, and the image-side surface is convex, the object-side surface of the fifth lens is concave, and the image-side surface is convex, the object-side surface of the sixth lens is convex, and the image-side surface is either concave or convex, and the object-side surface of the seventh lens is convex, and the image-side surface is concave;

[0055] Among them, when the mirror surface of each lens is convex, it is convex toward the object side; when the mirror surface is concave, it is convex toward the image side; when the mirror surface is convex, it is convex toward the image side; when the mirror surface is concave, it is convex toward the object side.

[0056] In this embodiment, the paraxial area refers to the area 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 area; 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 area. The surface of each lens close to the object side is called the object side surface of the lens, and the surface of each lens close to the image side is called the image side surface of the lens. The judgment of the surface shape in the paraxial area can be based on the judgment method of common knowledge in this field, and the positive and negative R value (R refers to the radius of curvature of the paraxial area, usually refers to the R value on the lens database (lens data) in the optical software) is used to judge the convexity and concavity. When the R value is positive, the lens surface is convex toward the object side, and when the R value is negative, the lens surface is convex toward the image side.

[0057] In this embodiment, the object side surface of the first lens is convex toward the object side, and the image side surface is convex toward the object side, the object side surface of the second lens is convex toward the image side, and the image side surface is convex toward the image side, the object side surface of the third lens is convex toward the object side, and the image side surface is convex toward the object side, the object side surface of the fourth lens is convex toward the image side, and the image side surface is convex toward the image side, the object side surface of the fifth lens is convex toward the image side, and the image side surface is convex toward the image side, the object side surface of the sixth lens is convex toward the object side, and the image side surface is convex toward the object side or convex toward the image side, and the object side surface of the seventh lens is convex toward the object side, and the image side surface is convex toward the object side.

[0058] This allows light to enter the optical system more effectively, ensuring smooth propagation without excessive deflection that would introduce greater aberrations. This also helps reduce the lens's aperture and overall length.

[0059] Optionally, the first lens, the third lens, and the sixth lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens, and the seventh lens are plastic aspherical lenses.

[0060] Since the refractive index of glass is generally higher than that of plastic, this alternating arrangement can offset wavelength separation during light refraction through the dispersion properties of glass and plastic, reducing residual chromatic aberration. For example, the glass spherical lens corrects primary chromatic aberration, while the plastic aspherical lens corrects marginal dispersion. This minimizes chromatic aberration throughout the lens. Furthermore, this alternating arrangement allows the glass spherical lens to provide basic refraction of light, while the plastic aspherical lens conforms to the trajectory of marginal light rays, minimizing overall lens distortion. Furthermore, this alternating arrangement contributes to overall lens weight reduction and lowers design costs. As a result, this lens utilizes three spherical and four aspherical lens elements to achieve high-quality imaging on a large aperture system, keeping the total length to under 48.04mm while minimizing both cost and size while ensuring clear resolution.

[0061] Optionally, the refractive index ND1 of the first lens is ≥1.74.

[0062] Among them, the first lens is the frontmost lens of the lens. Its higher refractive index helps the incident light at a large angle to be flattened more quickly, while ensuring the maximum range of information collection of the object to be measured, reducing the number of lenses and making the lens lightweight.

[0063] Optionally, the Abbe number VD4 of the fourth lens element and the Abbe number VD5 of the fifth lens element satisfy: VD5 / VD4≥2.3700.

[0064] Among them, these two lenses are cemented lenses. The positive and negative lens groups that meet this condition have a large difference in Abbe numbers, which can effectively correct the system chromatic aberration, improve the imaging quality, and make the detection effect clearer and more accurate.

[0065] Optionally, the optical power ΦZ1 of the focusing lens group and the optical power ΦZ2 of the fixed lens group satisfy the following relationship: 8.5800≤ΦZ1 / ΦZ2≤23.9200.

[0066] Among them, the optical focal length of these two groups is quite different. When the above conditions are met, high resolution can be achieved when the object distance is 100mm to 1000mm, and the resolution from the center to the edge of the field of view is highly consistent, which can effectively correct the field curvature changes caused by different object distances and improve the imaging quality during detection.

[0067] Optionally, the optical power Φ23 of the second to third lenses and the optical power Φ47 of the fourth to seventh lenses satisfy: 0.9000≤Φ23 / Φ47≤1.0700.

[0068] Where 0≤|DISG.MAX|≤0.20%, DISG.MAX represents the maximum optical distortion of the system. Lenses within this range, centered around the aperture, are arranged in a symmetrical optical power configuration. The front and rear lens groups have similar optical powers, effectively correcting the system's optical distortion and minimizing the effects of imaging distortion. This keeps the maximum optical distortion within ±0.20%, minimizing the system's field curvature, better reflecting the actual value of the measured object, and ensuring more accurate data from industrial inspections.

[0069] Optionally, a shape factor ξ2 of the second lens satisfies: 8.810≤|ξ2|≤19.110.

[0070] Optionally, a minimum value RI.MIN of the full-field relative illumination of the industrial lens satisfies: RI.MIN≥89.50%.

[0071] This lens is made of a high Abbe number material with positive optical power. Located in a position where light converges, it has a large shape factor. The shape factor is a parameter that influences the basic optical performance of a lens. By adjusting the shape factor through changes in lens curvature, aperture, material, and other factors, the system's focusing ability and imaging quality can be optimized. When the lens in this position meets these conditions, it can more effectively correct aberrations, improving image quality and relative illumination. The shape factor is primarily determined by the R and K values ​​and can be understood as the upper limit of the surface's aberration correction capabilities.

[0072] Furthermore, through the limitations of the aforementioned various relationship formulas, the lens can obtain an industrial lens with a focal length of 16mm, a working F number of 2.8, a focus object distance supporting 100mm to 1000mm, and high resolution, TTL ≤ 48.04mm, a maximum effective diameter of the lens ≤ 18.34mm, a maximum target surface that can support Φ9mm, a maximum field of view angle of 30°, and |maximum distortion| ≤ 0.2%.

[0073] To sum up, the technical solution of the embodiment of the present invention includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the optical axis from the object side to the image side; the first lens to the sixth lens form a focusing lens group, and the seventh lens is a fixed lens group; the fourth lens and the fifth lens are cemented to form a cemented lens; the total length TTL of the industrial lens and the focal length EFL of the industrial lens satisfy: 2.9600≤TTL / EFL≤2.9900; the total length TTL of the industrial lens and the maximum effective aperture DM of the lens in the industrial lens satisfy: 2.5500≤TTL / DM≤2.7800; the image plane size IM of the industrial lens and the working F number of the industrial lens satisfy: 3.1900≤IM / FNO≤3.2000; the field of view FOV of the industrial lens satisfies: FOV≥30.2100. Therefore, a structure of seven spherical and aspherical lenses is adopted. Through the combination of lens materials and the reasonable distribution of the optical focal length of each component, the front group focusing method is adopted, which has obvious cost advantages and realizes high-resolution focused imaging at object distances of 100mm to 1000mm. At the optimal object distance, it can take into account low distortion, large aperture and high-resolution industrial lens design. The focal length is 16mm, the maximum aperture is F2.8, the optimal object distance is 400mm, the |maximum optical distortion| is less than 0.20%, and the imaging quality can reach 200pl / mm>0.45MTF.

[0074] The industrial lens proposed by the present invention is described below with reference to specific embodiments 1 to 3.

[0075] The parameters corresponding to the rights protection requirements of the three embodiments in Table 1 are as follows:

[0076] Scope of protection Example 1 Example 2 Example 3 Lower limit Upper limit TTL / EFL 2.9665 2.9804 2.9687 2.9600 2.9900 TTL / DM 2.5556 2.7701 2.7299 2.5500 2.7800 IM / FNO 3.1950 3.1912 3.1910 3.1900 3.2000 EFL 15.7975 16.1153 16.1805 15.7900 16.1900 TTL 46.8640 48.0300 48.0350 46.8600 48.0400 DM 18.3379 17.3386 17.5958 17.3300 18.3400 FOV 30.9056 30.3470 30.2160 30.2100 30.9100 ND1 1.7495 1.9529 1.9656 1.7400 1.9700 VD5 / VD4 2.3703 2.3703 2.3703 2.3700 2.3800 ΦZ1 / ΦZ2 8.5841 23.9119 13.5412 8.5800 23.9200 Φ23 / Φ47 1.0672 0.9099 0.9298 0.9000 1.0700 |DISG.MAX| 0.20％ 0.20％ 0.20％ 0.00％ 0.20％ |ξ2| 19.102 14.065 8.818 8.810 19.110 RI.MIN 89.59％ 90.95％ 91.39％ 89.50％ 91.40％ Φ1 -0.0300 -0.0266 -0.0272 -0.0300 -0.0200 Φ2 0.0012 0.0104 0.0133 0.0010 0.0140 Φ3 0.0616 0.0416 0.0407 0.0400 0.0620 Φ45 0.0026 -0.0135 -0.0087 -0.0140 0.0030 Φ6 0.0420 0.0557 0.0533 0.0420 0.0560 Φ7 0.0069 0.0024 0.0043 0.0020 0.0070

[0077] Example 1

[0078] Figure 1 This is a schematic diagram of the structure of the industrial lens provided by the first embodiment of the present invention. Figure 1 As shown, the industrial lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7, wherein the object side surface of the first lens L1 is convex, and the image side surface is concave, the object side surface of the second lens L2 is concave, and the image side surface is convex, the object side surface of the third lens L3 is convex, and the image side surface is concave, the object side surface of the fourth lens L4 is concave, and the image side surface is convex, the object side surface of the fifth lens L5 is concave, and the image side surface is convex, the object side surface of the sixth lens L6 is convex, and the image side surface is concave, and the object side surface of the seventh lens L7 is convex, and the image side surface is concave.

[0079] Table 2 Design values ​​of industrial lens in Example 1

[0080]

[0081]

[0082] The surface numbers S1-S16 in Table 1 are numbered according to the order of the lens surfaces. The radius of curvature represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index represents the ability of the material between the current and next surfaces to deflect light. A blank space represents the current position as air, with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current and next surfaces. The semi-aperture represents half the aperture size of the current surface. The 12th surface spacing is 2.376mm, which allows focus to an object distance of 100mm. The 12th surface spacing is 0.099mm, which allows focus to an object distance of 1000mm.

[0083] Table 3 Design values ​​of aspheric coefficients of industrial lens in Example 1

[0084]

[0085] The K value in Table 2 represents the numerical value of the conic coefficient of the aspheric surface. The aspheric conic coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0086]

[0087] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the reciprocal of the curvature radius; k is the cone coefficient; AF is the coefficient of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspheric polynomial.

[0088] Figure 2 This is the ray fan diagram of the industrial lens provided in Example 1 of the present invention; the ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 2 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0089] Figure 3This is a field curvature distortion diagram of the industrial lens provided by the first embodiment of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, without a unit; T represents the meridian, S represents the sagittal; Figure 3 It can be seen that the field curvature of the lens provided in this embodiment is effectively controlled, that is, when imaging, the difference in image quality between the center and the periphery is small, and the consistency is good. In the coordinate system on the right, the horizontal coordinate represents the degree of distortion, in %, and the vertical coordinate represents the normalized image height, without a unit. Figure 3 It can be seen that the distortion of the lens provided in this embodiment is well corrected, and the optical distortion is less than ±0.2%.

[0090] Figure 4 This is the MTF diagram of the industrial lens provided in Example 1 of the present invention at an object distance of 400mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0091] Figure 5 This is the MTF diagram of the industrial lens provided in Example 1 of the present invention at an object distance of 100mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0092] Figure 6 This is the MTF diagram of the industrial lens provided in Example 1 of the present invention at an object distance of 1000mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0093] Example 2

[0094] Figure 7 This is a schematic diagram of the structure of the industrial lens provided by the second embodiment of the present invention. Figure 7 As shown, the industrial lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7, wherein the object side surface of the first lens L1 is convex, and the image side surface is concave, the object side surface of the second lens L2 is concave, and the image side surface is convex, the object side surface of the third lens L3 is convex, and the image side surface is concave, the object side surface of the fourth lens L4 is concave, and the image side surface is convex, the object side surface of the fifth lens L5 is concave, and the image side surface is convex, the object side surface of the sixth lens L6 is convex, and the image side surface is convex, and the object side surface of the seventh lens L7 is convex, and the image side surface is concave.

[0095] Table 4 Design values ​​of industrial lens of Example 2

[0096]

[0097]

[0098] The surface numbers S1-S16 in Table 4 are numbered according to the order of the lens surfaces. The radius of curvature represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index represents the ability of the material between the current and next surfaces to deflect light. A blank space represents the current position as air, with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current and next surfaces. The semi-aperture represents half the aperture size of the current surface. The 12th surface spacing is 2.508mm, which allows focus to an object distance of 100mm. The 12th surface spacing is 0.094mm, which allows focus to an object distance of 1000mm.

[0099] Table 5 Design values ​​of aspheric coefficients of industrial lens of Example 2

[0100]

[0101]

[0102] The K value in Table 5 represents the numerical value of the conic coefficient of the aspheric surface. The aspheric conic coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0103]

[0104] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the reciprocal of the curvature radius; k is the cone coefficient; AF is the coefficient of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspheric polynomial.

[0105] Figure 8 This is the ray fan diagram of the industrial lens provided in Example 2 of the present invention; the ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 8 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0106] Figure 9This is a field curvature distortion diagram of the industrial lens provided by the second embodiment of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; T represents the meridian, and S represents the sagittal; Figure 9 It can be seen that the field curvature of the lens provided in this embodiment is effectively controlled, that is, when imaging, the difference in image quality between the center and the periphery is small, and the consistency is good. In the coordinate system on the right, the horizontal coordinate represents the degree of distortion, in %, and the vertical coordinate represents the normalized image height, without a unit. Figure 9 It can be seen that the distortion of the lens provided in this embodiment is well corrected, and the optical distortion is less than ±0.2%.

[0107] Figure 10 This is the MTF diagram of the industrial lens provided in Example 2 of the present invention at an object distance of 400mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0108] Figure 11 This is the MTF diagram of the industrial lens provided in Example 2 of the present invention at an object distance of 100mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0109] Figure 12 This is the MTF diagram of the industrial lens provided in Example 2 of the present invention at an object distance of 1000mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0110] Example 3

[0111] Figure 13 This is a schematic diagram of the structure of the industrial lens provided by the third embodiment of the present invention. Figure 13 As shown, the industrial lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7, wherein the object side surface of the first lens L1 is convex, and the image side surface is concave, the object side surface of the second lens L2 is concave, and the image side surface is convex, the object side surface of the third lens L3 is convex, and the image side surface is concave, the object side surface of the fourth lens L4 is concave, and the image side surface is convex, the object side surface of the fifth lens L5 is concave, and the image side surface is convex, the object side surface of the sixth lens L6 is convex, and the image side surface is convex, and the object side surface of the seventh lens L7 is convex, and the image side surface is concave.

[0112] Table 6 Design values ​​of industrial lens of Example 3

[0113]

[0114]

[0115] The surface numbers S1-S16 in Table 6 are numbered according to the order of the lens surfaces. The radius of curvature represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index represents the ability of the material between the current and next surfaces to deflect light. A blank space represents the current position as air, with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current and next surfaces. The semi-aperture represents half the aperture of the current surface. The 12th surface spacing is 2.500mm, which allows focus to an object distance of 100mm. The 12th surface spacing is 0.096mm, which allows focus to an object distance of 1000mm.

[0116] Table 7 Design values ​​of aspheric coefficients of industrial lens in Example 3

[0117]

[0118] The K value in Table 7 represents the numerical value of the conic coefficient of the aspheric surface. The aspheric conic coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0119]

[0120] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the reciprocal of the curvature radius; k is the cone coefficient; AF is the coefficient of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspheric polynomial.

[0121] Figure 14 This is the ray fan diagram of the industrial lens provided in Example 3 of the present invention; the ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 14 It can be seen that the system's wavelengths in each field of view are all well aligned with the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the system's chromatic aberration is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0122] Figure 15This is a field curvature distortion diagram of the industrial lens provided by Example 3 of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, without a unit; T represents the meridian, S represents the sagittal; Figure 15 It can be seen that the field curvature of the lens provided in this embodiment is effectively controlled, that is, when imaging, the difference in image quality between the center and the periphery is small, and the consistency is good. In the coordinate system on the right, the horizontal coordinate represents the degree of distortion, in %, and the vertical coordinate represents the normalized image height, without a unit. Figure 15 It can be seen that the distortion of the lens provided in this embodiment is well corrected, and the optical distortion is less than ±0.2%.

[0123] Figure 16 This is the MTF diagram of the industrial lens provided in Example 3 of the present invention at an object distance of 400mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0124] Figure 17 This is the MTF diagram of the industrial lens provided in Example 3 of the present invention at an object distance of 100mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0125] Figure 18 This is the MTF diagram of the industrial lens provided in Example 3 of the present invention at an object distance of 1000mm. The image quality of the lens of the present invention at 200pl / mm from the center field of view to the edge field of view is higher than 0.45MTF, and the imaging has excellent resolution.

[0126] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. An industrial lens, characterized in that: The lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, which are arranged in sequence from the object side to the image side along the optical axis; the first lens to the sixth lens form a focusing lens group, and the seventh lens is a fixed lens group; the fourth lens and the fifth lens are cemented together to form a cemented lens; The total length TTL of the industrial lens and the focal length EFL of the industrial lens satisfy the following relationship: 2.9600≤TTL / EFL≤2.9900; The total length TTL of the industrial lens and the maximum effective aperture DM of the lens in the industrial lens satisfy the following relationship: 2.5500≤TTL / DM≤2.7800; The image plane size IM of the industrial lens and the working F number of the industrial lens satisfy the following relationship: 3.1900≤IM / FNO≤3.2000; The field of view (FOV) of the industrial lens satisfies: FOV ≥ 30.2100.

2. The industrial lens according to claim 1, characterized in that: The first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has optical power, the fifth lens has optical power, the sixth lens has positive optical power, and the seventh lens has positive optical power.

3. The industrial lens according to claim 1, characterized in that: The object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is concave, and the image-side surface is convex; the object-side surface of the third lens is convex, and the image-side surface is concave; the object-side surface of the fourth lens is concave, and the image-side surface is convex; the object-side surface of the fifth lens is concave, and the image-side surface is convex; the object-side surface of the sixth lens is convex, and the image-side surface is either concave or convex; and the object-side surface of the seventh lens is convex, and the image-side surface is concave; Among them, when the mirror surface of each lens is convex, it is convex toward the object side; when the mirror surface is concave, it is convex toward the image side; when the mirror surface is convex, it is convex toward the image side; when the mirror surface is concave, it is convex toward the object side.

4. The industrial lens according to claim 1, characterized in that: The first lens, the third lens, and the sixth lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens, and the seventh lens are plastic aspherical lenses.

5. The industrial lens according to claim 1, characterized in that: The refractive index ND1 of the first lens is ≥1.

74.

6. The industrial lens according to claim 1, characterized in that: The Abbe number VD4 of the fourth lens and the Abbe number VD5 of the fifth lens satisfy: VD5 / VD4≥2.3700.

7. The industrial lens according to claim 1, characterized in that: The optical power ΦZ1 of the focusing lens group and the optical power ΦZ2 of the fixed lens group satisfy the following relationship: 8.5800≤ΦZ1 / ΦZ2≤23.9200.

8. The industrial lens according to claim 1, characterized in that: The optical power Φ23 of the second to third lenses and the optical power Φ47 of the fourth to seventh lenses satisfy the following relationship: 0.9000≤Φ23 / Φ47≤1.0700.

9. The industrial lens according to claim 1, characterized in that: The shape factor ξ2 of the second lens satisfies: 8.810≤|ξ2|≤19.

110.

10. The industrial lens according to claim 1, characterized in that: The minimum value RI.MIN of the full-field relative illumination of the industrial lens satisfies: RI.MIN≥89.50%.

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