An industrial lens

Abstract

The utility model discloses an industrial lens, including fixed lens group, diaphragm and focusing lens group who arrange in proper order from object plane to image plane along the optical axis, fixed lens group fixed setting, focusing lens group removes setting along the optical axis direction. Fixed lens group includes first lens, second lens, third lens and fourth lens who arrange in proper order from object plane to image plane along the optical axis, and focusing lens group includes fifth lens, sixth lens and seventh lens who arrange in proper order from object plane to image plane along the optical axis. Industrial lens provided by the utility model embodiment adopts 4G3P (4 piece glass spherical surface lens and 3 piece plastic aspherical surface lens) structure, and through the reasonable setting lens number that each lens group contains, light power distribution and material collocation, has realized the industrial lens of high pixel, wide working range, small distortion, big imaging target surface.

Description

Technical Field

[0001] This utility model relates to the field of optical device technology, and in particular to an industrial lens. Background Technology

[0002] With the continuous development of industrial automation, the market demand for industrial lenses is also increasing. In order to improve the detection accuracy and reliability of lenses, they need to be able to focus continuously over a wide working range, have low optical distortion, and have a larger imaging target surface while maintaining extremely high spatial resolution.

[0003] However, existing industrial lenses generally suffer from problems such as low pixel count, narrow working distance range, large distortion, and small imaging target area, which limit the further improvement of visual inspection systems in terms of accuracy, stability, and applicable scenarios. Utility Model Content

[0004] This invention provides an industrial lens to solve the problems commonly found in existing industrial lenses, such as low pixel count, narrow working distance range, large distortion, and small imaging target area.

[0005] This utility model provides an industrial lens, including a fixed lens group, an aperture stop, and a focusing lens group arranged sequentially along the optical axis from the object plane to the image plane;

[0006] The fixed lens group is fixedly installed, and the focusing lens group is movable along the optical axis.

[0007] The fixed lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object plane to the image plane;

[0008] The focusing lens group includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object plane to the image plane;

[0009] The first lens has positive optical power;

[0010] The second lens has negative optical power;

[0011] The third lens has negative optical power;

[0012] The fourth lens has positive optical power;

[0013] The fifth lens has positive optical power;

[0014] The sixth lens has negative optical power;

[0015] The seventh lens has positive optical power;

[0016] The first lens, the second lens, the fourth lens, and the fifth lens are glass spherical lenses; the third lens, the sixth lens, and the seventh lens are plastic aspherical lenses.

[0017] Optionally, the refractive index of the first lens is Nd1, the refractive index of the second lens is Nd2, the refractive index of the third lens is Nd3, and the Abbe number of the third lens is Vd3; 1.75≤Nd1≤2.05; 1.87≤Nd2≤2.05; 1.48≤Nd3≤1.73; 20.38≤Vd3≤59.71.

[0018] Optionally, the optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, and the optical power of the industrial lens is φ; 0.08≤φ1 / φ≤0.25; -0.73≤φ2 / φ≤-0.48; -0.44≤φ3 / φ≤-0.29.

[0019] Optionally, the refractive index of the fourth lens is Nd4, and the refractive index of the fifth lens is Nd5; the Abbe number of the fourth lens is Vd4, and the Abbe number of the fifth lens is Vd5; 3.37≤Nd4+Nd5≤3.58; 47.29≤Vd5-Vd4≤62.99.

[0020] Optionally, the optical power of the fourth lens is φ4, the optical power of the fifth lens is φ5, and the optical power of the industrial lens is φ; 0.68≤(φ4+φ5) / φ≤1.03.

[0021] Optionally, the refractive index of the sixth lens is Nd6, and the refractive index of the seventh lens is Nd7; the Abbe number of the sixth lens is Vd6, and the Abbe number of the seventh lens is Vd7; 3.15≤Nd6+Nd7≤3.34; 5.86≤Vd7-Vd6≤35.21.

[0022] Optionally, the optical power of the sixth lens is φ6, the optical power of the seventh lens is φ7, and the optical power of the industrial lens is φ; -0.01≤(φ6+φ7) / φ≤0.24.

[0023] Optionally, the object-side surface of the first lens is convex, and the image-side surface of the first lens is concave.

[0024] The object-side surface of the second lens is convex, and the image-side surface of the second lens is concave.

[0025] The object-side surface of the third lens is convex, and the image-side surface of the third lens is concave.

[0026] The object-side surface of the fourth lens is concave, and the image-side surface of the fourth lens is convex.

[0027] The object-side surface of the fifth lens is convex, and the image-side surface of the fifth lens is convex.

[0028] The object-side surface of the sixth lens is concave, and the image-side surface of the sixth lens is also concave.

[0029] The object-side surface of the seventh lens is convex, and the image-side surface of the seventh lens is also convex.

[0030] Optionally, the air gap between the first lens and the second lens on the optical axis is T12; the air gap between the second lens and the third lens on the optical axis is T23; the air gap between the third lens and the fourth lens on the optical axis is T34; the air gap between the fifth lens and the sixth lens on the optical axis is T56; the air gap between the sixth lens and the seventh lens on the optical axis is T67; the distance from the object side of the first lens to the aperture on the optical axis is T14; the distance from the aperture to the image plane on the optical axis is T57; 4.03≤T14 / (T12+T23+T34)≤5.94; 5.05≤T57 / (T56+T67)≤15.45.

[0031] Optionally, the focal length of the industrial lens is EFFL, the imaging target diameter of the industrial lens is IC, and the field of view of the industrial lens is FOV; 0.77≤FOV / EFFL / IC≤0.81.

[0032] The industrial lens provided in this embodiment adopts a 4G3P (4 glass lenses and 3 plastic lenses) structure, which is a mixture of glass spherical lenses and plastic aspherical lenses. By reasonably setting the number of lenses in each lens group, the distribution of optical power and the combination of materials, an industrial lens with high pixel count, wide working range, low distortion and large imaging target area is achieved. The lens has good imaging performance, with an aperture F ≤ 2.5, a total optical length TTL ≤ 60mm, an imaging target area IC ≥ 11.2mm, and optical distortion ≤ 3%.

[0033] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the structure of an industrial lens at an object distance of 400mm, provided for an embodiment of this utility model;

[0036] Figure 2 A schematic diagram of another industrial lens provided for an embodiment of this utility model at an object distance of 400mm;

[0037] Figure 3 A schematic diagram of the structure of another industrial lens provided in this embodiment of the present invention at an object distance of 400mm;

[0038] Figure 4 A spherical aberration curve of an industrial lens provided in Embodiment 1 of this utility model at an object distance of 400mm;

[0039] Figure 5 Field curvature distortion diagram of an industrial lens provided in Embodiment 1 of this utility model at an object distance of 400mm;

[0040] Figure 6 A chromatic aberration curve of the industrial lens provided in Embodiment 1 of this utility model at an object distance of 400mm.

[0041] Figure 7 A spherical aberration curve of an industrial lens provided in Embodiment 2 of this utility model at an object distance of 400mm;

[0042] Figure 8 Field curvature distortion diagram of the industrial lens provided in Embodiment 2 of this utility model at an object distance of 400mm;

[0043] Figure 9 A chromatic aberration curve of the industrial lens provided in Embodiment 2 of this utility model at an object distance of 400mm;

[0044] Figure 10 A spherical aberration curve of an industrial lens provided in Embodiment 3 of this utility model at an object distance of 400mm;

[0045] Figure 11 Field curvature distortion diagram of the industrial lens provided in Embodiment 3 of this utility model at an object distance of 400mm;

[0046] Figure 12The vertical chromatic aberration curve of the industrial lens provided in Embodiment 3 of this utility model at an object distance of 400mm. Detailed Implementation

[0047] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0048] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0049] Figure 1 This is a schematic diagram of the structure of an industrial lens at an object distance of 400mm, provided as an embodiment of the present invention. Figure 2 This is a schematic diagram of another industrial lens provided in an embodiment of the present invention at an object distance of 400mm. Figure 3 This is a schematic diagram of another industrial lens provided as an embodiment of the present invention at an object distance of 400mm. (See attached diagram.) Figures 1-3 As shown, the industrial lens provided in this embodiment of the present invention includes a fixed lens group 10, an aperture stop STO, and a focusing lens group 20 arranged sequentially along the optical axis from the object plane to the image plane. The fixed lens group 10 is fixedly disposed, while the focusing lens group 20 is movable along the optical axis. The fixed lens group 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 arranged sequentially along the optical axis from the object plane to the image plane. The focusing lens group 20 includes a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object plane to the image plane.

[0050] The first lens L1 has positive optical power; the second lens L2 has negative optical power; the third lens L3 has negative optical power; the fourth lens L4 has positive optical power; the fifth lens L5 has positive optical power; the sixth lens L6 has negative optical power; and the seventh lens L7 has positive optical power.

[0051] The first lens L1, the second lens L2, the fourth lens L4, and the fifth lens L5 are glass spherical lenses; the third lens L3, the sixth lens L6, and the seventh lens L7 are plastic aspherical lenses.

[0052] Specifically, such as Figures 1-3 As shown, the fixed lens group 10, the aperture stop STO, and the focusing lens group 20 can be housed in a single lens barrel (not shown in the figure), but are not limited to this.

[0053] The fixed lens group 10 is positioned within the lens barrel so that it remains stationary relative to the image plane, and its optical correction state does not change with the object distance. Since the fixed lens group 10 is stationary and does not participate in focusing motion, it avoids aberration fluctuations caused by overall lens group movement. This reduces the impact on resolution at different object distances, ensuring balanced image quality at various working distances and thus guaranteeing consistent imaging quality across different working distances.

[0054] The focusing lens group 20, acting as a focusing motion group, can reciprocate along the optical axis within the lens barrel to flexibly adjust the focusing position of the optical system and achieve focusing at different object distances. Through the overall displacement of the focusing lens group 20, the lens can complete focusing within a wider working distance range (e.g., 200mm to 800mm or more), adapting to the actual needs of industrial sites with large variations in target height and diverse detection distances, thereby improving the versatility and automation level of the equipment.

[0055] The fixed lens group 10 consists of four lenses, arranged sequentially from the object side to the image side along the optical axis: first lens L1, second lens L2, third lens L3, and fourth lens L4.

[0056] The focusing lens group 20 consists of three lenses, which are arranged along the optical axis from the object side to the image side as follows: the fifth lens L5, the sixth lens L6, and the seventh lens L7.

[0057] The first lens L1 has positive optical power, and the second lens L2 has negative optical power, which allows more light to enter the optical system and expands the field of view.

[0058] The third lens L3 has negative optical power, which can effectively reduce light rays, lower the light propagation height inside the lens, and reduce the aberrations it produces.

[0059] The fourth lens L4 has positive optical power, the fifth lens L5 has positive optical power, the sixth lens L6 has negative optical power, and the seventh lens L7 has positive optical power. These features can compensate for chromatic aberration, thereby improving the imaging performance of the optical system.

[0060] Furthermore, aspherical lenses, with their freeform surface shape, can simultaneously correct multiple aberrations such as spherical aberration, coma, and astigmatism on a single mirror surface, especially exhibiting superior correction capabilities for higher-order aberrations compared to spherical lenses. In this embodiment, three aspherical lenses are respectively arranged on the third lens L3, the sixth lens L6, and the seventh lens L7, strategically positioning them at key positions in the front, middle, and rear of the optical path. Without increasing the total number of lenses, this significantly improves the system's aberration correction capability and imaging uniformity, while also considering manufacturing costs and mass production feasibility.

[0061] At the same time, the use of aspherical lenses reduces the reliance on complex lens combinations and additional correction elements, enabling a reduction in the overall length of the lens and a simplification of the number of lenses (7-element structure) while maintaining high performance.

[0062] Among them, the aspherical sixth lens L6 and seventh lens L7 are arranged in the focusing lens group 20, which can compensate for aberration drift caused by changes in object distance in real time during focusing, and ensure stable image quality throughout the focusing process.

[0063] The remaining four lenses are all spherical lenses. Spherical lens manufacturing technology is mature, has high consistency, and can reduce costs.

[0064] Furthermore, the spherical lenses (first lens L1, second lens L2, fourth lens L4, and fifth lens L5) are made of glass. Glass has a stable refractive index and a wide Abbe number range, providing excellent chromatic aberration and aberration correction capabilities for spherical lenses with both positive and negative optical powers. Simultaneously, glass has an extremely low coefficient of thermal expansion and hygroscopicity, ensuring that the core optical power of the lens remains stable over a wide temperature range and in humid environments. Moreover, as a key positive optical power element in the fixed lens group 10 and the focusing lens group 20, the long-term mechanical stability and anti-aging properties of the glass lenses help ensure the continuous and reliable operation of the industrial lens under harsh working conditions.

[0065] The aspherical lenses (third lens L3, sixth lens L6, and seventh lens L7) are all made of plastic. Plastic is easily molded into high-precision aspherical surfaces through injection molding. Its freeform surface characteristics allow for simultaneous correction of spherical aberration, coma, and astigmatism on a single surface, significantly optimizing image quality, especially beneficial for controlling distortion and field curvature. Simultaneously, the lightweight nature of plastic lenses helps reduce the moment of inertia of the focusing lens group 20, improving focusing speed and accuracy. Furthermore, plastic materials and molding processes offer significant cost advantages for mass production. In addition, plastic aspherical lenses can be flexibly designed as negative optical power (such as third lens L3 and sixth lens L6) for light control and aberration balance, or as positive optical power (such as seventh lens L7) for converging light and image plane flattening, complementing the functions of glass spherical lenses.

[0066] Furthermore, the STO (Stable Tolerance) aperture is a variable-aperture mechanical structure located inside the lens barrel. The STO controls the amount of light reaching the image sensor by adjusting the aperture size, thus affecting the depth of field of the image. The STO also blocks unwanted light from entering the lens, preventing flare or ghosting caused by stray light, and improving image contrast and sharpness. A properly set STO can help reduce certain types of aberrations, such as spherical aberration and coma, improving image quality.

[0067] In this embodiment, placing the aperture stop STO in the optical path between the fixed lens group 10 and the focusing lens group 20 can most effectively limit the final beam aperture participating in imaging, that is, determine the aperture number F of the lens. It intercepts stray light from the excessively large aperture and excessively biased angle (especially the edge field of view) generated by the fixed lens group 10, making the light entering the focusing lens group 20 more regular. This helps to keep the aberration characteristics of the lens (such as field curvature and distortion) relatively stable under different apertures and reduce image quality fluctuations caused by aperture changes.

[0068] The industrial lens provided in this embodiment adopts a 4G3P (4 glass lenses and 3 plastic lenses) structure, which is a mixture of glass spherical lenses and plastic aspherical lenses. By reasonably setting the number of lenses in each lens group, the distribution of optical power and the combination of materials, an industrial lens with high pixel count, wide working range, low distortion and large imaging target area is achieved. The lens has good imaging performance, with an aperture F ≤ 2.5, a total optical length TTL ≤ 60mm, an imaging target area IC ≥ 11.2mm, and optical distortion ≤ 3%.

[0069] As a feasible implementation, the refractive index of the first lens L1 is Nd1, the refractive index of the second lens L2 is Nd2, the refractive index of the third lens L3 is Nd3, and the Abbe number of the third lens L3 is Vd3; 1.75≤Nd1≤2.05; 1.87≤Nd2≤2.05; 1.48≤Nd3≤1.73; 20.38≤Vd3≤59.71.

[0070] The refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe a material's ability to refract light, and different materials have different refractive indices. The higher the refractive index, the stronger the material's ability to bend light.

[0071] The Abbe number is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number.

[0072] In this embodiment, the first lens L1 and the second lens L2 are made of high refractive index materials, which facilitates more light entering the optical system and expands the field of view.

[0073] The refractive index and Abbe number of the third lens L3 meet the above conditions, which can effectively reduce the light rays, lower the light propagation height inside the lens, and reduce the aberrations they produce.

[0074] As a feasible implementation method, the optical power of the first lens L1 is φ1, the optical power of the second lens L2 is φ2, the optical power of the third lens L3 is φ3, and the optical power of the industrial lens is φ; 0.08≤φ1 / φ≤0.25; -0.73≤φ2 / φ≤-0.48; -0.44≤φ3 / φ≤-0.29.

[0075] When the optical power of the first lens L1 and the second lens L2 meets the above range, it is beneficial for more light to enter the optical system and expand the field of view.

[0076] When the optical power of the third lens L3 meets the above range, it can effectively reduce the light beam, lower the light propagation height inside the lens, and reduce the aberrations it produces.

[0077] As a feasible implementation, the refractive index of the fourth lens L4 is Nd4, and the refractive index of the fifth lens L5 is Nd5; the Abbe number of the fourth lens L4 is Vd4, and the Abbe number of the fifth lens L5 is Vd5; 3.37≤Nd4+Nd5≤3.58; 47.29≤Vd5-Vd4≤62.99.

[0078] When the refractive index and Abbe number of the fourth lens L4 and the fifth lens L5 meet the above range, the dispersion can compensate for each other to achieve the purpose of eliminating chromatic aberration, which is beneficial to improving the imaging performance of the optical system.

[0079] As a feasible implementation, the optical power of the fourth lens L4 is φ4, and the optical power of the fifth lens L5 is φ5; 0.68≤(φ4+φ5) / φ≤1.03.

[0080] When the optical power of the fourth lens L4 and the fifth lens L5 meets the above range, the dispersion can be mutually compensated to achieve the purpose of eliminating chromatic aberration, which is beneficial to improving the imaging performance of the optical system.

[0081] As a feasible implementation, the refractive index of the sixth lens L6 is Nd6, and the refractive index of the seventh lens L7 is Nd7; the Abbe number of the sixth lens L6 is Vd6, and the Abbe number of the seventh lens L7 is Vd7; 3.15≤Nd6+Nd7≤3.34; 5.86≤Vd7-Vd6≤35.21.

[0082] When the refractive index and Abbe number of the sixth lens L6 and the seventh lens L7 meet the above range, the dispersion can compensate for each other to achieve the purpose of eliminating chromatic aberration, which is beneficial to improving the imaging performance of the optical system.

[0083] As a feasible implementation, the optical power of the sixth lens L6 is φ6, and the optical power of the seventh lens L7 is φ7; -0.01≤(φ6+φ7)≤0.24.

[0084] When the optical power of the sixth lens L6 and the seventh lens L7 meets the above range, the dispersion can be mutually compensated to achieve the purpose of eliminating chromatic aberration, which is beneficial to improving the imaging performance of the optical system.

[0085] It should be noted that, by rationally matching the optical power of each lens, this embodiment of the utility model can achieve the required optical performance indicators (such as high pixel count, wide working range, low distortion, large imaging target area, etc.) while making the path of light smoother when passing through the entire industrial lens, reducing unnecessary reflection and absorption, which is beneficial to improving light transmission and imaging quality.

[0086] As a possible implementation method, such as Figures 1-3 As shown, 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 convex, and the image-side surface is concave. 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 convex, and the image-side surface is convex. The object-side surface of the sixth lens L6 is concave, and the image-side surface is concave. The object-side surface of the seventh lens L7 is convex, and the image-side surface is convex.

[0087] The shape of the lens affects the direction of light propagation, determining how light bends as it passes through the lens, which in turn affects the amount of light transmitted through the lens and the quality and characteristics of the image.

[0088] In this embodiment, the first lens L1 and the second lens L2 are meniscus glass spherical lenses that are convex in the front and concave in the back, which can facilitate more light entering the optical system and expand the field of view.

[0089] The third lens, L3, is a convex-concave plastic aspherical lens that effectively constricts light rays, reduces the propagation height of light rays inside the lens, and minimizes the resulting aberrations.

[0090] The fourth lens L4 is a concave-convex glass spherical lens, the fifth lens L5 is a biconvex glass spherical lens, the sixth lens L6 is a biconcave plastic aspherical lens, and the seventh lens L7 is a biconvex plastic aspherical lens. These features can compensate for chromatic aberration, thereby achieving the purpose of eliminating chromatic aberration and improving the imaging performance of the optical system.

[0091] Meanwhile, in this embodiment, by rationally matching the surface shapes of each lens, while meeting the optical power requirements of each lens and achieving the required optical performance indicators (such as high pixel count, wide working range, low distortion, and large imaging target area), it is beneficial to further reduce the overall optical length of the entire industrial lens, thereby realizing a miniaturized lens design. Furthermore, it can make the path of light smoother when passing through the entire industrial lens, reducing unnecessary reflection and absorption, which is beneficial to improving light transmission and imaging quality.

[0092] As a feasible implementation, the air gap between the first lens L1 and the second lens L2 on the optical axis is T12; the air gap between the second lens L2 and the third lens L3 on the optical axis is T23; the air gap between the third lens L3 and the fourth lens L4 on the optical axis is T34; the air gap between the fifth lens L5 and the sixth lens L6 on the optical axis is T56; the air gap between the sixth lens L6 and the seventh lens L7 on the optical axis is T67; the distance on the optical axis from the object side of the first lens L1 to the aperture stop STO is T14; the distance on the optical axis from the aperture stop STO to the image plane is T57; 4.03≤T14 / (T12+T23+T34)≤5.94; 5.05≤T57 / (T56+T67)≤15.45.

[0093] Adjusting the air gap between different lenses helps to achieve the characteristics of low distortion, low chromatic aberration, and low field curvature.

[0094] As a feasible implementation method, the focal length of the industrial lens is EFFL, the imaging target diameter of the industrial lens is IC, and the field of view of the industrial lens is FOV; 0.77≤FOV / EFFL / IC≤0.81.

[0095] When an industrial lens meets the above conditions, it can reduce the light propagation height inside the lens, reduce the aberrations it produces, and make the light path and refraction angle on both sides of the image consistent or close, which helps to reduce field curvature and distortion and improve the uniformity of the full field of view imaging.

[0096] As a possible implementation method, such as Figures 1-3 As shown, the focusing lens group 20 also includes a filter CG, which is located on the image side of the seventh lens L7. It can protect the image sensor from dust and contamination, thereby ensuring the imaging effect of the lens.

[0097] In some cases, the filter CG can also be used to correct specific aberrations or filter out unwanted light, and this embodiment of the present invention does not specifically limit this.

[0098] As a feasible implementation method, the sixth lens L6 and the seventh lens L7 can be bonded together with adhesive to form a cemented lens group. Bonding the sixth lens L6 and the seventh lens L7 can effectively correct chromatic aberration, reduce lens eccentricity sensitivity, balance lens aberrations, and improve image quality. Simultaneously, it can reduce lens assembly sensitivity, thereby reducing the difficulty of lens manufacturing processes and improving lens assembly yield.

[0099] As a possible implementation method, such as Figures 1-3 As shown, the distance between the sixth lens L6 and the seventh lens L7 on the optical axis is greater than 0. The sixth lens L6 and the seventh lens L7 can be supported by a spacer, making them independent lenses. This reduces production costs and makes it easier to adjust and optimize the sixth lens L6 and the seventh lens L7, thus helping to adapt to different optical design requirements and improve image quality.

[0100] The following describes specific embodiments of industrial lenses applicable to the above-described embodiments with reference to the accompanying drawings.

[0101] Example 1

[0102] Continue to refer to Figure 1 The industrial lens provided in Embodiment 1 of this utility model includes a fixed lens group 10, an aperture stop STO, and a focusing lens group 20 arranged sequentially along the optical axis from the object plane to the image plane.

[0103] The fixed lens group 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 arranged sequentially along the optical axis from the object plane to the image plane.

[0104] The focusing lens group 20 includes a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object plane to the image plane.

[0105] The filter CG is located on the image-side side of the seventh lens L7.

[0106] Table 1 details the specific optical physical parameters of each lens in the industrial lens provided in Embodiment 1 of this utility model, using a feasible implementation method. The industrial lenses in Table 1 correspond to... Figure 1 The industrial lens shown.

[0107] Table 1 Design values ​​of optical physical parameters for industrial lenses

[0108]

[0109] The surface numbers in Table 1 are assigned according to the surface sequence of each lens. "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on. "STO" represents the aperture stop of the lens. "IMA" represents the image plane of the lens. The radius of curvature represents the curvature of the lens surface; a positive value indicates the surface bends towards the image plane, and a negative value indicates the surface bends towards the object plane. "Infinity" indicates the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index Nd represents the ability of the material between the current and next surfaces to deflect light; a blank space indicates the current location is air with a refractive index of 1. The Abbe number Vd represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The semi-diameter represents the effective diameter of the lens. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0110] Table 2 details the focal interval design values ​​of the industrial lens provided in Embodiment 1 of this utility model, according to a feasible implementation method.

[0111] Table 2. Design values ​​for focusing interval of industrial lenses

[0112]

[0113] In this embodiment, the aspherical conic coefficient of the aspherical lens in the industrial lens can be defined using the following aspherical formula, but is not limited to the following representation:

[0114] ;

[0115] in, The axial sagitta in the Z-direction of the aspherical surface; The height of the aspherical surface; To fit the curvature of the sphere, it is numerically the reciprocal of the radius of curvature; To fit the conic coefficients; - For the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th and 16th order terms of the aspherical polynomial.

[0116] For example, Table 3 details the aspherical coefficients of each lens in this embodiment one by way of a feasible implementation.

[0117] Table 3 Design values ​​of aspherical coefficients for various lenses in industrial lenses

[0118]

[0119] The industrial lens provided in Example 1 has a total optical length (TTL) of 59.52 mm and an image height (Ф11.2 mm) corresponding to an angle of 71°.

[0120] Figure 4 The figure shows the spherical aberration curves of the industrial lens provided in Embodiment 1 of this utility model at an object distance of 400mm. The curves in the figure represent axial aberrations. The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius. The horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging. As can be seen from the figure, the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the industrial lens achieves good control of spherical aberration at various wavelengths, meeting the requirements for wide-spectrum applications.

[0121] Figure 5 This is a field curvature distortion diagram of the industrial lens provided in Embodiment 1 of this utility model at an object distance of 400mm. In the left coordinate system of the figure, the horizontal axis represents the magnitude of the field curvature of the optical system, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. As can be seen from the figure, the lens provided in this embodiment effectively controls the field curvature from light with wavelengths from 449nm to 680nm, that is, during imaging, the difference between the image quality in the center and the image quality at the periphery is small. In the right coordinate system, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit. As can be seen from the figure, the distortion of the lens provided in this embodiment is well corrected, and the imaging distortion is small, meeting the usage requirements of the optical system.

[0122] Figure 6The figure shows the transverse chromatic aberration curve of the industrial lens provided in Embodiment 1 of this utility model at an object distance of 400mm. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex of the transverse direction represents the maximum pupil radius. The dominant wavelength is 570nm, and the horizontal direction represents the offset relative to the dominant wavelength, in micrometers (μm). As can be seen from the figure, the transverse chromatic aberration at different wavelengths is controlled within a reasonable range, indicating that the transverse chromatic aberration of this industrial lens is well controlled and can meet the requirements of wide-spectrum applications across the entire wavelength range.

[0123] Example 2

[0124] Continue to refer to Figure 2 The industrial lens provided in Embodiment 2 of this utility model includes a fixed lens group 10, an aperture stop STO, and a focusing lens group 20 arranged sequentially along the optical axis from the object plane to the image plane.

[0125] The fixed lens group 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 arranged sequentially along the optical axis from the object plane to the image plane.

[0126] The focusing lens group 20 includes a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object plane to the image plane.

[0127] The filter CG is located on the image-side side of the seventh lens L7.

[0128] Table 4 details the specific optical physical parameters of each lens in the industrial lens provided in Embodiment 2 of this utility model, using a feasible implementation method. The industrial lenses in Table 4 correspond to... Figure 2 The industrial lens shown.

[0129] Table 4 Design values ​​of optical physical parameters for industrial lenses

[0130]

[0131] The surface numbers in Table 4 are assigned according to the surface sequence of each lens. "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on. "STO" represents the aperture stop of the lens. "IMA" represents the image plane of the lens. The radius of curvature represents the curvature of the lens surface; a positive value indicates the surface bends towards the image plane, and a negative value indicates the surface bends towards the object plane. "Infinity" indicates the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index Nd represents the ability of the material between the current and next surfaces to deflect light; a blank space indicates the current location is air with a refractive index of 1. The Abbe number Vd represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The semi-diameter represents the effective diameter of the lens. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0132] Table 5 details the focal interval design values ​​of the industrial lens provided in Embodiment 2 of this utility model, according to a feasible implementation method.

[0133] Table 5. Design values ​​for the focusing interval of industrial lenses

[0134]

[0135] In this embodiment, the aspherical conic coefficient of the aspherical lens in the industrial lens can be defined using the following aspherical formula, but is not limited to the following representation:

[0136] ;

[0137] in, The axial sagitta in the Z-direction of the aspherical surface; The height of the aspherical surface; To fit the curvature of the sphere, it is numerically the reciprocal of the radius of curvature; To fit the conic coefficients; - For the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th and 16th order terms of the aspherical polynomial.

[0138] For example, Table 6 details the aspherical coefficients of each lens in this second embodiment with a feasible implementation.

[0139] Table 6 Design values ​​of aspherical coefficients for various lenses in industrial lenses

[0140]

[0141] The industrial lens provided in Example 2 has a total optical length (TTL) of 60mm and an image height (Ф11.2mm) corresponding to an angle of 70.54°.

[0142] Figure 7 This is a spherical aberration curve of the industrial lens provided in Embodiment 2 of this utility model at an object distance of 400mm. The curves in the figure are axial aberration curves. The vertical direction represents the normalization of the aperture, 0 indicates that it is on the optical axis, and the vertical vertex represents the maximum pupil radius. The horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging. As can be seen from the figure, the axial aberration of different wavelengths is controlled within the range of (-0.05mm, +0.05mm), indicating that the industrial lens has achieved good control of spherical aberration at various wavelengths, which can meet the requirements of wide-spectrum applications.

[0143] Figure 8 This is a field curvature distortion diagram of the industrial lens provided in Embodiment 2 of this utility model at an object distance of 400mm. In the left coordinate system of the figure, the horizontal axis represents the magnitude of the field curvature of the optical system, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. As can be seen from the figure, the lens provided in this embodiment effectively controls the field curvature of light from wavelengths of 449nm to 680nm, that is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the right coordinate system, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit. As can be seen from the figure, the distortion of the lens provided in this embodiment is well corrected, and the imaging distortion is small, meeting the usage requirements of the optical system.

[0144] Figure 9 The figure shows the transverse chromatic aberration curve of the industrial lens provided in Embodiment 2 of this utility model at an object distance of 400mm. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the transverse direction represents the maximum pupil radius. The dominant wavelength is 570nm, and the horizontal direction represents the offset relative to the dominant wavelength, in micrometers (μm). As can be seen from the figure, the transverse chromatic aberration at different wavelengths is controlled within a reasonable range, indicating that the transverse chromatic aberration of this industrial lens is well controlled and can meet the requirements of wide-spectrum applications across the entire wavelength range.

[0145] Example 3

[0146] Continue to refer to Figure 3 The industrial lens provided in Embodiment 3 of this utility model includes a fixed lens group 10, an aperture stop STO, and a focusing lens group 20 arranged sequentially along the optical axis from the object plane to the image plane.

[0147] The fixed lens group 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 arranged sequentially along the optical axis from the object plane to the image plane.

[0148] The focusing lens group 20 includes a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object plane to the image plane.

[0149] The filter CG is located on the image-side side of the seventh lens L7.

[0150] Table 7 details the specific optical physical parameters of each lens in the industrial lens provided in Embodiment 3 of this utility model, using a feasible implementation method. The industrial lenses in Table 7 correspond to... Figure 3 The industrial lens shown.

[0151] Table 7 Design values ​​of optical physical parameters for industrial lenses

[0152]

[0153] The surface numbers in Table 7 are assigned according to the surface sequence of each lens. "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on. "STO" represents the aperture stop of the lens. "IMA" represents the image plane of the lens. The radius of curvature represents the curvature of the lens surface; a positive value indicates the surface bends towards the image plane, and a negative value indicates the surface bends towards the object plane. "Infinity" indicates the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index Nd represents the ability of the material between the current and next surfaces to deflect light; a blank space indicates the current location is air with a refractive index of 1. The Abbe number Vd represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The semi-diameter represents the effective diameter of the lens. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0154] Table 8 details the focal interval design values ​​of the industrial lens provided in Embodiment 3 of this utility model, according to a feasible implementation method.

[0155] Table 8. Design values ​​for the focusing interval of industrial lenses

[0156]

[0157] In this embodiment, the aspherical conic coefficient of the aspherical lens in the industrial lens can be defined using the following aspherical formula, but is not limited to the following representation:

[0158] ;

[0159] in, The axial sagitta in the Z-direction of the aspherical surface; The height of the aspherical surface; To fit the curvature of the sphere, it is numerically the reciprocal of the radius of curvature; To fit the conic coefficients; - For the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th and 16th order terms of the aspherical polynomial.

[0160] For example, Table 9 details the aspherical coefficients of each lens in this embodiment three according to a feasible implementation.

[0161] Table 9 Design values ​​of aspherical coefficients for various lenses in industrial lenses

[0162]

[0163] The industrial lens provided in Example 3 has a total optical length (TTL) of 59.92 mm and an image height (Ф11.2 mm) corresponding to an angle of 71.2°.

[0164] Figure 10 This is a spherical aberration curve of the industrial lens provided in Embodiment 3 of this utility model at an object distance of 400mm. The curve in the figure is the axial aberration curve. The vertical direction represents the normalization of the aperture, 0 indicates that it is on the optical axis, and the vertical vertex represents the maximum pupil radius. The horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging. As can be seen from the figure, the axial aberration of different wavelengths is controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this industrial lens is well controlled at each wavelength, which can meet the requirements of wide-spectrum applications.

[0165] Figure 11 This is a field curvature distortion diagram of the industrial lens provided in Embodiment 3 of this utility model at an object distance of 400mm. In the left coordinate system of the figure, the horizontal axis represents the magnitude of the field curvature of the optical system, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. As can be seen from the figure, the lens provided in this embodiment effectively controls the field curvature of light from wavelengths of 449nm to 680nm, that is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the right coordinate system, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit. As can be seen from the figure, the distortion of the lens provided in this embodiment is well corrected, and the imaging distortion is small, meeting the usage requirements of the optical system.

[0166] Figure 12The figure shows the transverse chromatic aberration curve of the industrial lens provided in Embodiment 3 of this utility model at an object distance of 400mm. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the transverse direction represents the maximum pupil radius. The dominant wavelength is 570nm, and the horizontal direction represents the offset relative to the dominant wavelength, in micrometers (μm). As can be seen from the figure, the transverse chromatic aberration at different wavelengths is controlled within a reasonable range, indicating that the transverse chromatic aberration of this industrial lens is well controlled and can meet the requirements of wide-spectrum applications across the entire wavelength range.

[0167] To provide a clearer explanation of the above embodiments, Table 10 details the specific optical physical parameters of each lens in the industrial lens provided in embodiments one to three of this utility model.

[0168] Table 10 Design values ​​of optical physical parameters for industrial lenses

[0169]

[0170] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An industrial lens, characterized in that, It includes a fixed lens group, an aperture stop, and a focusing lens group arranged sequentially along the optical axis from the object plane to the image plane; The fixed lens group is fixedly installed, and the focusing lens group is movable along the optical axis. The fixed lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object plane to the image plane; The focusing lens group includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object plane to the image plane; The first lens has positive optical power; The second lens has negative optical power; The third lens has negative optical power; The fourth lens has positive optical power; The fifth lens has positive optical power; The sixth lens has negative optical power; The seventh lens has positive optical power; The first lens, the second lens, the fourth lens, and the fifth lens are glass spherical lenses; the third lens, the sixth lens, and the seventh lens are plastic aspherical lenses.

2. The industrial lens according to claim 1, characterized in that, The first lens has a refractive index of Nd1, the second lens has a refractive index of Nd2, the third lens has a refractive index of Nd3, and the Abbe number of the third lens is Vd3; 1.75≤Nd1≤2.05; 1.87≤Nd2≤2.05; 1.48≤Nd3≤1.73; 20.38≤Vd3≤59.

71.

3. The industrial lens according to claim 1, characterized in that, The optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, and the optical power of the industrial lens is φ. 0.08≤φ1 / φ≤0.25; -0.73≤φ2 / φ≤-0.48; -0.44≤φ3 / φ≤-0.

29.

4. The industrial lens according to claim 1, characterized in that, The refractive index of the fourth lens is Nd4, and the refractive index of the fifth lens is Nd5; the Abbe number of the fourth lens is Vd4, and the Abbe number of the fifth lens is Vd5; 3.37≤Nd4+Nd5≤3.58; 47.29≤Vd5-Vd4≤62.

99.

5. The industrial lens according to claim 1, characterized in that, The optical power of the fourth lens is φ4, the optical power of the fifth lens is φ5, and the optical power of the industrial lens is φ. 0.68≤(φ4+φ5) / φ≤1.

03.

6. The industrial lens according to claim 1, characterized in that, The refractive index of the sixth lens is Nd6, and the refractive index of the seventh lens is Nd7; the Abbe number of the sixth lens is Vd6, and the Abbe number of the seventh lens is Vd7; 3.15≤Nd6+Nd7≤3.34; 5.86≤Vd7-Vd6≤35.

21.

7. The industrial lens according to claim 1, characterized in that, The optical power of the sixth lens is φ6, the optical power of the seventh lens is φ7, and the optical power of the industrial lens is φ; -0.01≤(φ6+φ7) / φ≤0.

24.

8. 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 of the first lens is concave. The object-side surface of the second lens is convex, and the image-side surface of the second lens is concave. The object-side surface of the third lens is convex, and the image-side surface of the third lens is concave. The object-side surface of the fourth lens is concave, and the image-side surface of the fourth lens is convex. The object-side surface of the fifth lens is convex, and the image-side surface of the fifth lens is convex. The object-side surface of the sixth lens is concave, and the image-side surface of the sixth lens is also concave. The object-side surface of the seventh lens is convex, and the image-side surface of the seventh lens is also convex.

9. The industrial lens according to claim 1, characterized in that, The air gap between the first lens and the second lens on the optical axis is T12; the air gap between the second lens and the third lens on the optical axis is T23; the air gap between the third lens and the fourth lens on the optical axis is T34; the air gap between the fifth lens and the sixth lens on the optical axis is T56; the air gap between the sixth lens and the seventh lens on the optical axis is T67; the distance from the object side of the first lens to the aperture on the optical axis is T14; the distance from the aperture to the image plane on the optical axis is T57. 4.03≤T14 / (T12+T23+T34)≤5.94; 5.05≤T57 / (T56+T67)≤15.

45.

10. The industrial lens according to claim 1, characterized in that, The focal length of the industrial lens is EFFL, the diameter of the imaging target surface of the industrial lens is IC, and the field of view of the industrial lens is FOV; 0.77≤FOV / EFFL / IC≤0.81.

Images