Industrial lens

Abstract

The invention discloses an industrial lens. The industrial lens comprises a focusing lens group and a fixed lens group which are arranged along an optical axis from an object side to an image side; the focusing lens group moves along the optical axis for focusing; the focusing lens group comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power and an eighth lens with positive focal power which are arranged along an optical axis from an object side to an image side; a ninth lens with positive focal power and a tenth lens with negative focal power; the fixed lens group comprises an eleventh lens with positive focal power and a twelfth lens with negative focal power which are arranged along the optical axis from the object side to the image side; the first to twelfth lenses are glass lenses. The maximum value DISG.MAX of the optical distortion of the industrial lens meets the condition that DISG.MAX is smaller than or equal to 0.1000%. The industrial lens provided by the invention can be suitable for a large-range working distance, and has the characteristics of large aperture, high imaging resolution and low optical distortion.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of optical devices, and in particular, to an industrial lens. Background Art

[0002] With the progress of technology and the continuous development of the intelligent industry, the application of lenses is no longer limited to traditional photography. Its application fields have gradually expanded to industrial inspection, robot vision, etc. As a core component in industrial inspection and robot vision, etc., the imaging quality of industrial lenses is one of the key factors affecting inspection and recognition results.

[0003] To ensure that products have high production efficiency and production yield, and that machine vision recognition has high recognition accuracy, the requirements for various performance of industrial lenses required for inspection and recognition are continuously increasing. How to improve the performance of industrial lenses, such as resolution, applicable working distance, optical distortion, aperture, etc., has become a technical problem that needs to be solved urgently at present. Summary of the Invention

[0004] The present invention provides an industrial lens to ensure that the industrial lens has a large applicable working distance range, a larger aperture, a high imaging resolution, and a low optical distortion.

[0005] The present invention provides an industrial lens, which includes: a focusing lens group and a fixed lens group arranged in sequence along the optical axis from the object side to the image side; the focusing lens group moves for focusing along the optical axis;

[0006] The focusing lens group includes a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with positive optical power, a ninth lens with positive optical power, and a tenth lens with negative optical power arranged in sequence along the optical axis from the object side to the image side;

[0007] The fixed lens group includes an eleventh lens with positive optical power and a twelfth lens with negative optical power arranged in sequence along the optical axis from the object side to the image side;

[0008] Among them, the first lens to the twelfth lens are all glass lenses;

[0009] The maximum value DISG.MAX of the optical distortion of the industrial lens satisfies: |DISG.MAX| ≤ 0.1000%.

[0010] Optionally, the overall focal length EFL of the industrial lens satisfies: 2.1950 ≤ TTL / EFL ≤ 2.2300;

[0011] Among them, TTL is the distance from the front end of the first lens to the image plane of the industrial lens.

[0012] Optionally, the shape factor ξ1 of the first lens satisfies: 1.1500 ≤ |ξ1| ≤ 1.6800.

[0013] Optionally, the Abbe number Vd4 of the fourth lens and the Abbe number Vd5 of the fifth lens satisfy: 2.4100 ≤ Vd5 / Vd4.

[0014] Optionally, the Abbe number Vd5 of the fifth lens and the Abbe number Vd6 of the sixth lens satisfy: 1.6900 ≤ Vd5 / Vd6.

[0015] Optionally, the total optical power Φ4-6 of the fourth lens to the sixth lens and the total optical power Φ7-8 of the seventh lens to the eighth lens satisfy: -1.1500 ≤ Φ4-6 / Φ7-8 ≤ -1.0800.

[0016] Optionally, the optical power Φ11 of the eleventh lens and the optical power Φ12 of the twelfth lens satisfy: -0.8900 ≤ Φ11 / Φ12 ≤ -0.7200.

[0017] Optionally, the total optical power Φ2-7 of the second lens to the seventh lens and the total optical power Φ8-10 of the eighth lens to the tenth lens satisfy: -1.0300 ≤ Φ2-7 / Φ8-10 ≤ -0.9100.

[0018] Optionally, the maximum effective aperture DM among the effective apertures of the first lens to the twelfth lens satisfies: 3.5400 ≤ TTL / DM ≤ 3.7800;

[0019] wherein, TTL is the distance from the front end of the first lens to the image plane of the industrial lens.

[0020] Optionally, the field of view FOV of the industrial lens satisfies: FOV ≥ 21.1000°; and / or,

[0021] The f-number F.NO of the industrial lens satisfies: F.NO ≤ 2.3100.

[0022] The technical solution of the present invention is to form an industrial lens by using a total of twelve glass lenses, namely the first lens to the twelfth lens with optical power. The first lens to the tenth lens form a focusing lens group, and the eleventh lens and the twelfth lens form a fixed lens group. By reasonably distributing the optical power of each lens, the focal length of the industrial lens can reach 50 mm within the working distance of 200 mm to 1000 mm, the optimal object distance is 300 mm, the maximum aperture F of the industrial lens can reach 2.2, and the maximum value of optical distortion DISG.MAX can be less than 0.1%, so as to meet the imaging requirements of low distortion and high resolution, enabling the industrial lens to have a high resolution ability and ensuring that the industrial lens can have a high imaging quality. For example, the imaging quality can reach MTF180 lp / mm > 0.4. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a schematic structural diagram of an industrial lens provided by an embodiment of the present invention at the optimal object distance;

[0024] Figure 2 is Figure 1 a schematic diagram of the light fan structure of the industrial lens shown at the optimal object distance;

[0025] Figure 3 is Figure 1 a schematic diagram of the field curvature distortion curve of the industrial lens shown at the optimal object distance;

[0026] Figure 4 is Figure 1 a schematic diagram of the MTF of the industrial lens shown at the optimal object distance;

[0027] Figure 5 is Figure 1 a schematic diagram of the axial chromatic aberration of the industrial lens shown at the optimal object distance;

[0028] Figure 6 is Figure 1 a schematic diagram of the lateral chromatic aberration of the industrial lens shown at the optimal object distance;

[0029] Figure 7 FIG. is a schematic structural diagram of another industrial lens provided by an embodiment of the present invention at the optimal object distance;

[0030] Figure 8 is Figure 7 a schematic diagram of the light fan structure of the industrial lens shown at the optimal object distance;

[0031] Figure 9 is Figure 7 a schematic diagram of the field curvature distortion curve of the industrial lens shown at the optimal object distance;

[0032] Figure 10 isFigure 7 Schematic diagram of MTF of the industrial lens shown at the optimal object distance;

[0033] Figure 11 is Figure 7 Schematic diagram of axial chromatic aberration of the industrial lens shown at the optimal object distance;

[0034] Figure 12 is Figure 7 Schematic diagram of lateral chromatic aberration of the industrial lens shown at the optimal object distance;

[0035] Figure 13 is the schematic diagram of the structure of another industrial lens provided by the embodiment of the present invention at the optimal object distance;

[0036] Figure 14 is Figure 13 Schematic diagram of the light fan structure of the industrial lens shown at the optimal object distance;

[0037] Figure 15 is Figure 13 Schematic diagram of the field curvature and distortion curve of the industrial lens shown at the optimal object distance;

[0038] Figure 16 is Figure 13 Schematic diagram of MTF of the industrial lens shown at the optimal object distance;

[0039] Figure 17 is Figure 13 Schematic diagram of axial chromatic aberration of the industrial lens shown at the optimal object distance;

[0040] Figure 18 is Figure 13 Schematic diagram of lateral chromatic aberration of the industrial lens shown at the optimal object distance. Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the present invention clearer, the following will, in combination with the accompanying drawings in the embodiments of the present invention, completely describe the technical solutions of the present invention through specific implementation manners. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Without departing from the spirit or scope of the present invention, various modifications and variations can be made to the present invention, which are obvious to those skilled in the art. Therefore, the present invention is intended to cover the modifications and variations of the present invention that fall within the scope of the corresponding claims (the claimed technical solutions) and their equivalents.

[0042] Moreover, the "first", "second" and similar terms used in the embodiments of the present disclosure do not denote any order, quantity or importance, but are merely used to distinguish different components. Similarly, similar terms such as "a", "an" or "the" do not denote a quantity limitation, but mean that there is at least one. Terms such as "comprising" or "including" mean that the elements or objects appearing before the term cover the elements or objects listed after the term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly. In addition, in the embodiments of the present disclosure, the descriptions of "same", "equal", etc. do not mean that the two objects have exactly the same size and exactly the same shape, and it is allowed to be approximately the same and approximately equal within a certain error range.

[0043] It should be noted that the embodiments provided in the embodiments of the present invention can be combined with each other without conflict.

[0044] Figure 1 is a schematic structural diagram of an industrial lens provided by an embodiment of the present invention at the optimal object distance, as Figure 1 shown, the industrial lens includes: a focusing lens group G1 and a fixed lens group G2 arranged in sequence along the optical axis from the object side to the image side; the focusing lens group G1 moves along the optical axis for focusing; the focusing lens group G1 includes a first lens 10 with positive optical power, a second lens 20 with negative optical power, a third lens 30 with positive optical power, a fourth lens 40 with negative optical power, a fifth lens 50 with positive optical power, a sixth lens 60 with negative optical power, a seventh lens 70 with positive optical power, an eighth lens 80 with positive optical power, a ninth lens 90 with positive optical power and a tenth lens 100 with negative optical power arranged in sequence along the optical axis from the object side to the image side; the fixed lens group G2 includes an eleventh lens 110 with positive optical power and a twelfth lens 120 with negative optical power arranged in sequence along the optical axis from the object side to the image side.

[0045] It can be understood that the optical power is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, and it characterizes the ability of the optical system to deflect light rays. The greater the absolute value of the optical power, the stronger the bending ability of the light rays, and the smaller the absolute value of the optical power, the weaker the bending ability of the light rays. When the optical power is positive, the refraction of the light rays is convergent; when the optical power is negative, the refraction of the light rays is divergent. The optical power can be used to characterize a certain refracting surface of a lens (i.e., a surface of the lens), can be used to characterize a certain lens, or can be used to characterize a system formed by multiple lenses together (i.e., a lens group).

[0046] In this embodiment, the first lens 10 in the focusing lens group G1 is set to have a positive optical power, the second lens 20 is set to have a negative optical power, the third lens 30 is set to have a positive optical power, the fourth lens 40 is set to have a negative optical power, the fifth lens 50 is set to have a positive optical power, the sixth lens 60 is set to have a negative optical power, the seventh lens 70 is set to have a positive optical power, the eighth lens 80 is set to have a positive optical power, the ninth lens 90 is set to have a positive optical power, and the tenth lens 100 is set to have a negative optical power. And the eleventh lens 110 in the fixed lens group G2 is set to have a positive optical power, and the twelfth lens 120 is set to have a negative optical power. That is, the optical powers of the respective lenses are reasonably distributed so that the lenses cooperate with each other. Within the working distance of 200 mm to 1000 mm, the focal length of the industrial lens can reach 50 mm by moving the focusing lens group G1, and the maximum aperture F can reach 2.2. At the same time, the imaging quality requirements of low distortion and high resolution are satisfied, so that the industrial lens has a high resolution ability. Among them, the optimal object distance of the industrial lens can be 300 mm, and the imaging quality of the industrial lens can reach MTF180 lp / mm > 0.4.

[0047] As a feasible embodiment, the value range of the optical power Φ1 of the first lens 10 is 0.0140 ≤ Φ1 ≤ 0.0160; the value range of the optical power Φ2 of the second lens 20 is -0.0280 ≤ Φ2 ≤ -0.0250; the value range of the optical power Φ3 of the third lens 30 is 0.0210 ≤ Φ3 ≤ 0.0240; the value range of the optical power Φ4 of the fourth lens 40 is -0.0470 ≤ Φ4 ≤ -0.0410; the value range of the optical power Φ5 of the fifth lens 50 is 0.0350 ≤ Φ5 ≤ 0.0380; the value range of the optical power Φ6 of the sixth lens 60 is -0.0460 ≤ Φ6 ≤ -0.0420; the value range of the optical power Φ7 of the seventh lens 70 is 0.0180 ≤ Φ7 ≤ 0.0220; the value range of the optical power Φ8 of the eighth lens 80 is 0.0270 ≤ Φ8 ≤ 0.0300; the value range of the optical power Φ9 of the ninth lens 90 is 0.0330 ≤ Φ9 ≤ 0.0420; the value range of the optical power Φ10 of the tenth lens 100 is -0.0540 ≤ Φ10 ≤ -0.0440; the value range of the optical power Φ11 of the eleventh lens 110 is 0.0110 ≤ Φ11 ≤ 0.0180; the value range of the optical power Φ12 of the twelfth lens 120 is -0.0220 ≤ Φ12 ≤ -0.0150. In this way, by reasonably setting the value ranges of the optical powers of the respective lenses, the imaging requirements of large aperture, low distortion, and high resolution can be satisfied.

[0048] Optionally, the maximum value DISG.MAX of the optical distortion of the industrial lens satisfies: |DISG.MAX| ≤ 0.1000%. In this way, by making the absolute value of the maximum value DISG.MAX of the optical distortion of the industrial lens less than 0.1%, that is, the industrial lens as a whole has a low optical distortion, the distortion phenomenon during the imaging of the industrial lens is improved, and the imaging quality of the industrial lens is improved.

[0049] Optionally, the first lens 10 to the twelfth lens 120 are all glass lenses.

[0050] Among them, the lens made of glass has a small thermal expansion coefficient and good stability, so that the glass lens can have higher thermal stability and can ensure good resolution ability of the industrial lens within a wide temperature range (-40°C to 80°C) when bearing more optical power. In addition, compared with plastic lenses, the range of glass materials that can be selected is wider, and the refractive index and Abbe constant can be selected relatively freely, which can control the higher-order aberrations and chromatic aberrations of the industrial lens to a certain extent and meet the usage requirements under complex conditions.

[0051] Optionally, a first diaphragm 130 is further provided in the focusing lens group G1. The first diaphragm 130 is disposed on the optical path between the first lens 10 and the second lens 20, and the first diaphragm 130 can adjust the propagation direction of the light beam passing through the first lens 10.

[0052] Optionally, a second diaphragm 140 is further provided in the focusing lens group G1. The second diaphragm 140 is disposed in the optical path between the sixth lens 60 and the seventh lens 70, and the second diaphragm can adjust the propagation direction of the light beam passing through the sixth lens 60.

[0053] Optionally, the fourth lens 40, the fifth lens 50, and the sixth lens 60 form a triple cemented lens.

[0054] Among them, the fact that the fourth lens 40, the fifth lens 50 and the sixth lens 60 are adhesively bonded can be understood as that the image side of the fourth lens 40 is attached to the object side of the fifth lens 50, and the image side of the fifth lens 50 is attached to the object side of the sixth lens 60. By forming a triple cemented lens with the fourth lens 40, the fifth lens 50 and the sixth lens 60, the air gap between the fourth lens 40 and the fifth lens 50 and the air gap between the fifth lens 50 and the sixth lens 60 can be reduced, which helps to reduce the overall optical length of the industrial lens. It can also reduce the sensitivity to tolerances such as tilt / eccentricity generated during the lens assembly process, simplify the assembly procedure in the industrial lens manufacturing process, and improve the equipment efficiency. At the same time, the fact that the fourth lens 40, the fifth lens 50 and the sixth lens 60 are adhesively bonded can also reduce the light loss caused by reflection between the lenses, improve the illuminance, and reduce the risk of ghost images. In addition, the cemented lens can be used to minimize or eliminate chromatic aberration, so as to improve the image quality, reduce the reflection loss of light energy, and enhance the clarity of the lens imaging. In an optional embodiment, the fourth lens 40 and the fifth lens 50 can be supported by a spacer or adhesively bonded with glue, and the fifth lens 50 and the sixth lens 60 can also be supported by a spacer or adhesively bonded with glue. The embodiments of the present invention do not limit the specific adhesive bonding method.

[0055] Optionally, the ninth lens 90 and the tenth lens 100 form a doublet lens.

[0056] Among them, the fact that the ninth lens 90 and the tenth lens 100 are adhesively bonded can be understood as that the image side of the ninth lens 90 is attached to the object side of the tenth lens 100. By adhesively bonding the ninth lens 90 and the tenth lens 100, the air gap between the ninth lens 90 and the tenth lens 100 can be reduced, which helps to reduce the overall optical length of the industrial lens. It can also reduce the sensitivity to tolerances such as tilt / eccentricity generated during the lens assembly process, simplify the assembly procedure in the industrial lens manufacturing process, and improve the equipment efficiency. At the same time, the fact that the ninth lens 90 and the tenth lens 100 are adhesively bonded can also reduce the light loss caused by reflection between the lenses and improve the illuminance. In addition, the cemented lens can be used to minimize or eliminate chromatic aberration, so as to improve the image quality, reduce the reflection loss of light energy, and enhance the clarity of the lens imaging. In an optional embodiment, the ninth lens 90 and the tenth lens 100 can be supported by a spacer or adhesively bonded with glue. The embodiments of the present invention do not limit the specific adhesive bonding method.

[0057] On the basis of the above embodiments, optionally, the overall focal length EFL of the industrial lens satisfies: 2.1950 ≤ TTL / EFL ≤ 2.2300; where TTL is the distance from the front end of the first lens 10 to the image plane IMG of the industrial lens.

[0058] Among them, the distance between the front end of the first lens 10 and the image plane IMG of the industrial lens can be understood as the total optical system length of the industrial lens. By making the value range of the ratio of the total optical system length TTL of the industrial lens to its overall focal length EFL between 2.1950 and 2.2300, it is beneficial to reduce the volume of the optical system of the industrial lens, enable the industrial lens to adapt to more usage environments, and reduce the material cost of the lens.

[0059] Optionally, the shape factor ξ1 of the first lens 10 satisfies: 1.1500 ≤ |ξ1| ≤ 1.6800.

[0060] Among them, the shape factor, as a parameter affecting the basic optical performance of the lens, can optimize the focusing ability and imaging quality of the entire optical system of the industrial lens by adjusting the curvature, aperture, material, etc. of the lens. The material of the first lens 10 can be a high refractive index material, and the optical power of the first lens 10 is positive, and it is located near the first aperture 130. By making the first lens 10 have a larger shape factor, such that the shape factor of the first lens 10 satisfies 1.1500 ≤ |ξ1| ≤ 1.6800, it is possible to more effectively correct aberrations and improve imaging quality.

[0061] Optionally, the Abbe number Vd4 of the fourth lens 40 and the Abbe number Vd5 of the fifth lens 50 satisfy: 2.4100 ≤ Vd5 / Vd4.

[0062] Among them, the fourth lens 40 and the fifth lens 50 form a cemented lens. By making the ratio of the Abbe number Vd5 of the fifth lens 50 to the Abbe number Vd4 of the fourth lens 40 greater than or equal to 2.1400, a large difference is created between the Abbe number Vd4 of the fourth lens 40 and the Abbe number Vd5 of the fifth lens 50, so that chromatic aberration of the system can be effectively corrected, imaging quality can be improved, and imaging clarity is higher, so that when using the industrial lens for defect detection, etc., a higher detection effect can be achieved, and the detection result has higher accuracy.

[0063] Optionally, the Abbe number Vd5 of the fifth lens 50 and the Abbe number Vd6 of the sixth lens 60 satisfy: 1.6900 ≤ Vd5 / Vd6.

[0064] Among them, the fifth lens 50 and the sixth lens 60 form a cemented lens. By making the ratio of the Abbe number Vd5 of the fifth lens 50 to the Abbe number Vd6 of the sixth lens 60 greater than or equal to 1.6900, a large difference is created between the Abbe number Vd5 of the fifth lens 50 and the Abbe number Vd6 of the sixth lens 60, so that chromatic aberration of the system can be effectively corrected, the imaging quality can be improved, and higher imaging clarity can be achieved. When using an industrial lens for defect detection and the like, a higher detection effect can be obtained, and the detection result has higher accuracy. At the same time, the fourth lens 40, the fifth lens 50, and the sixth lens 60 form a triple cemented lens. By making the Abbe number Vd4 of the fourth lens 40 and the Abbe number Vd5 of the fifth lens 50 satisfy Vd5 / Vd4≥2.4100, and the Abbe number Vd5 of the fifth lens 50 and the Abbe number Vd6 of the sixth lens 60 satisfy Vd5 / Vd6≥1.6900, a large difference is created between the Abbe numbers of adjacent two lenses in the triple cemented lens, so that chromatic aberration of the system can be effectively corrected, the imaging quality can be improved, and the detection effect is clearer and more accurate.

[0065] Optionally, the total optical power Φ4-6 of the fourth lens 40 to the sixth lens 60 and the total optical power Φ7-8 of the seventh lens 70 to the eighth lens 80 satisfy: -1.1500≤Φ4-6 / Φ7-8≤-1.0800.

[0066] Among them, the total optical power Φ4-6 of the fourth lens 40 to the sixth lens 60 can be understood as the overall optical power of the lens group formed by the fourth lens 40 to the sixth lens 60, and the total optical power Φ7-8 of the seventh lens 70 to the eighth lens 80 can be understood as the overall optical power of the lens group formed by the seventh lens 70 to the eighth lens 80. The lens group formed by the fourth lens 40 to the sixth lens 60 and the lens group formed by the seventh lens 70 to the eighth lens 80 are located in the middle position of the optical system of the entire industrial lens, and the ray height is relatively high. By making the total optical power Φ4-6 of the fourth lens 40 to the sixth lens 60 and the total optical power Φ7-8 of the seventh lens 70 to the eighth lens 80 satisfy the above conditions, the overall optical power of the lens group formed by the fourth lens 40 to the sixth lens 60 is opposite to the overall optical power of the lens group formed by the seventh lens 70 to the eighth lens 80, that is, the fourth lens 40 to the eighth lens 80 form two lens groups, and the two lens groups have positive optical power and negative optical power respectively. At the same time, the absolute values of the two lens groups are close, which can effectively reduce spherical aberration, reduce the defocus amount between different wavelengths, and improve the on-axis imaging quality. When applying the industrial lens to defect detection and the like, a higher detection effect can be obtained, and the detection result is clearer and more accurate.

[0067] Optionally, the optical power Φ11 of the eleventh lens 110 and the optical power Φ12 of the twelfth lens 120 satisfy: -0.8900≤Φ11 / Φ12≤-0.7200.

[0068] Among them, the lens group composed of the eleventh lens 110 and the twelfth lens 120 is located at the last position of the optical system of the industrial lens, and the ratio of the optical powers of the eleventh lens 110 and the twelfth lens 120 is negative, so that the optical powers of the eleventh lens 110 and the twelfth lens 120 are positive and negative respectively, and there is a large difference between the two, forming a Petzval scene, which can effectively correct field curvature and improve the consistency of the overall image resolution of the picture, and is more conducive to realizing the optical system design of a large aperture.

[0069] Optionally, the total optical power Φ2-7 of the second lens 20 to the seventh lens 70 and the total optical power Φ8-10 of the eighth lens 80 to the tenth lens 100 satisfy: -1.0300 ≤ Φ2-7 / Φ8-10 ≤ -0.9100.

[0070] Among them, the total optical power Φ2-7 of the second lens 20 to the seventh lens 70 can be understood as the overall optical power of the lens group composed of the second lens 20 to the seventh lens 70, and the total optical power Φ8-10 of the eighth lens 80 to the tenth lens 100 can be understood as the overall optical power of the lens group composed of the eighth lens 80 to the tenth lens 100. By making the ratio of the total optical power Φ2-7 of the second lens 20 to the seventh lens 70 to the total optical power Φ8-10 of the eighth lens 80 to the tenth lens 100 negative, the optical powers of the lens group composed of the second lens 20 to the seventh lens 70 and the lens group composed of the eighth lens 80 to the tenth lens 100 are opposite, and the absolute values of the two lens groups are close, forming an optical power symmetric structure, which can effectively correct the optical distortion of the system, reduce the distortion during imaging, ensure the integrity of the sampling of the object to be measured, and improve the detection accuracy.

[0071] Optionally, the maximum effective aperture DM among the effective apertures of the first lens 10 to the twelfth lens 12 satisfies: 3.5400 ≤ TTL / DM ≤ 3.7800; where, TTL is the distance from the front end of the first lens 10 to the image plane IMG of the industrial lens.

[0072] Among them, the distance between the front end of the first lens 10 and the image plane IMG of the industrial lens can be understood as the total length of the optical system of the industrial lens. The effective aperture of the lens can reflect the maximum light passing ability of the lens and directly affect the illuminance of the focal plane. Limiting the ratio of the total length TTL of the optical system to the maximum effective aperture DM among the lenses to meet the above conditions can make the total length of the optical system of the industrial lens shorter and the maximum effective aperture DM smaller when the image height remains unchanged, and the corresponding volume is smaller, so that the volume can be reduced while realizing a large image height.

[0073] Optionally, the field of view (FOV) of the industrial lens satisfies: FOV ≥ 21.1000°. With such a setting, the industrial lens can have a larger field of view and meet the detection requirements of a high detection range.

[0074] Optionally, the f-number (F.NO) of the industrial lens satisfies: F.NO ≤ 2.3100.

[0075] Among them, for an industrial lens with a large target surface and a large aperture, it usually has a huge size and requires many lenses for aberration correction. However, in the embodiment of the present invention, only 12 glass spherical lenses with optical power can achieve a high-quality imaging picture on an ultra-large target surface. While controlling the total length within 115.45 mm, both the cost and volume are minimized, and clear resolution quality is ensured.

[0076] Based on the above embodiment, optionally, the object side of the first lens 10 is convex and the image side is concave, that is, the first lens 10 can be a meniscus lens; the object side and the image side of the second lens 20 are both concave; the object side and the image side of the third lens 30 are both convex; the object side and the image side of the fourth lens 40 are both concave; the object side and the image side of the fifth lens 50 are both convex; the object side and the image side of the sixth lens 60 are both concave; the object side of the seventh lens 70 is concave and the image side is convex; the object side and the image side of the eighth lens 80 are both convex; the object side and the image side of the ninth lens 90 are both convex; the object side and the image side of the tenth lens 100 are both concave; the object side and the image side of the eleventh lens 110 are both convex; the object side and the image side of the twelfth lens 120 are both concave.

[0077] Among them, the object side of the lens can be understood as the surface of the lens close to the object surface, and the image side of the lens can be understood as the surface of the lens close to the image surface. The object side of the lens being concave can be understood as the object side of the lens being recessed towards the object surface at the near optical axis position, and the object side of the lens being convex can be understood as the object side of the lens being protruded towards the object surface at the near optical axis position; the image side of the lens being concave can be understood as the image side of the lens being recessed towards the image surface at the near optical axis position, and the image side of the lens being convex can be understood as the image side of the lens being protruded towards the image surface at the near optical axis position.

[0078] In this embodiment, by reasonably setting the surface shapes of each lens, the light path can be ensured to be smoother, the relative illuminance of the image can be improved, the imaging effect can be enhanced, thereby facilitating the reduction of optical distortion, improving the detection effect, and ensuring the clarity and accuracy of detection.

[0079] In summary, in the embodiments of the present invention, the structure of an industrial lens is composed of 12 glass spherical lenses with optical power. By reasonably setting the materials of each lens and reasonably distributing the optical power of each lens, the industrial lens can take into account the industrial lens design with low distortion, large target surface, and high resolution within the working distance range of 200 mm - 1000 mm. Moreover, the overall focal length EFL of the optical system of the industrial lens can reach 50 mm, the maximum aperture F can reach 2.2, the optimal object distance can be 300 mm, the maximum optical distortion DISG.MAX can meet |DISG.MAX| < 0.1%, and the imaging quality can reach MTF 180 lp / mm > 0.4, thereby realizing a high-performance industrial lens design solution.

[0080] The following further describes specific embodiments of the industrial lens applicable to the above embodiments with reference to the accompanying drawings.

[0081] In a feasible embodiment, Table 1 details, in a feasible implementation manner, Figure 1 the specific optical physical parameters of the industrial lens shown.

[0082] Table 1 Design of an Optical Physical Parameter of the Industrial Lens

[0083] Scope of protection Example 1 Lower limit Upper limit TTL / EFL 2.2219 2.1950 2.2300 TTL / DM 3.5822 3.5400 3.7800 EFL 51.2260 50.6500 52.6100 TTL 113.8190 112.9400 115.5400 DM 31.7734 31.7700 33.3200 FOV 22.1733 21.1000 22.4200 F.NO 2.2399 2.2100 2.3100 Vd5 / Vd4 3.7521 2.4100 3.8500 Vd5 / Vd6 3.6039 1.6900 3.6700 Φ4-6 / Φ7-8 -1.1335 -1.1500 -1.0800 Φ11 / Φ12 -0.8807 -0.8900 -0.7200 Φ2-7 / Φ8-10 -0.9965 -1.0300 -0.9100 DISG.MAX -0.0945％ -0.1000％ 0.0000％ ξ1 1.6724 1.1500 1.6800 Φ1 0.0157 0.0140 0.0160 Φ2 -0.0267 -0.0280 -0.0250 Φ3 0.0233 0.0210 0.0240 Φ4 -0.0428 -0.0470 -0.0410 Φ5 0.0356 0.0350 0.0380 Φ6 -0.0426 -0.0460 -0.0420 Φ4-6 -0.0511 -0.0570 -0.0500 Φ7 0.0182 0.0180 0.0220 Φ8 0.0278 0.0270 0.0300 Φ9 0.0411 0.0330 0.0420 Φ10 -0.0537 -0.0540 -0.0440 Φ9-10 -0.0046 -0.0040 -0.0070 Φ11 0.0165 0.0110 0.0180 Φ12 -0.0187 -0.0220 -0.0150

[0084] Table 2 shows the design parameters such as the surface type, radius of curvature, thickness, and material of each lens in an industrial lens corresponding to Table 1.

[0085] Table 2 Design of a Parameter of Each Lens in the Industrial Lens

[0086]

[0087] The industrial lens of this embodiment includes a first lens 10, a first diaphragm 130, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, a second diaphragm 140, a seventh lens 70, an eighth lens 80, a ninth lens 90, a tenth lens 100, an eleventh lens 110, a twelfth lens 120, and a filter glass 150, which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the surface order of each lens. Among them, "1" represents the object side surface of the first lens 10, "2" represents the image side surface of the first lens 10, and so on. "IMG" represents the image plane of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface bends towards the image side, and a negative value represents that the surface bends towards the object side. Among them, "infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light. A space represents that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light. A space represents that the current position is air; the semi-aperture represents half of the aperture size of the current surface. When the interval of the 20th surface in the industrial lens of this embodiment is 23.008 mm, it can be focused to an object distance of 200 mm. When the interval of the 20th surface is 9.422 mm, it can be focused to an object distance of 1000 mm.

[0088] Figure 2 Yes Figure 1 Schematic diagram of the light fan structure of the industrial lens shown at the optimal object distance. The light fan diagram is one of the most commonly used evaluation methods in modern optical design. As Figure 2 shown, the abscissa is the beam aperture and the ordinate is the lateral aberration. The most ideal curve is a straight line that coincides with the abscissa, indicating that all light rays converge at the same point on the image plane. The corresponding interval on the ordinate of the curve is the maximum dispersion range of the beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths (460 nm, 530 nm, 620 nm) but also represent the magnitude of the lateral chromatic aberration. As Figure 2 can be seen, the industrial lens closely approaches the abscissa at each wavelength (460 nm, 530 nm, 620 nm) in each field of view, indicating that the lateral aberration of each wavelength of the optical system of the industrial lens is well corrected. At the same time, there is no obvious dispersion among the wavelengths, indicating that the system chromatic aberration is also well corrected, thus ensuring that the optical system can meet the high-resolution imaging requirements.

[0089] Figure 3 Yes Figure 1 Schematic diagram of the field curvature and distortion curve of the industrial lens shown at the optimal object distance. As Figure 3As shown in the figure, in the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without unit; where T represents the meridian and S represents the sagittal; from Figure 3 it can be seen that the lens provided in this embodiment is effectively controlled in terms of field curvature, that is, when imaging, the image quality difference between the center and the periphery is small, and the consistency is good; in the coordinate system on the right side, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without unit; from Figure 3 it can be seen that the distortion of the industrial lens provided in this embodiment is well corrected, and the optical distortion is all less than ±0.1%.

[0090] Figure 4 is Figure 1 the MTF schematic diagram of the industrial lens shown at the optimal object distance. The MTF diagram is one of the most commonly used and authoritative evaluation methods in modern optical design. The abscissa is the spatial frequency of the line pairs in the object space imaged on the image plane by the optical system, with the unit of cycle / mm, and the ordinate is the modulus value of the optical transfer function. The variation trends of the optical transfer function in the meridian (such as T shown in the figure) and sagittal (such as S shown in the figure) directions corresponding to different fields of view (such as 0.00mm, 3.45mm, 5.75mm, 8.05mm, 10.53mm, and 11.50mm shown in the figure) as the spatial frequency increases. The most ideal curve is a straight line that coincides with the system diffraction limit, indicating that the geometric aberration of the light rays at all positions is less than the wavefront aberration generated by the physical limitation of the system itself and can be ignored. From Figure 4 it can be known that the image quality of the industrial lens from the central field of view to the edge field of view at 180 pl / mm is higher than 0.4 MTF, and the imaging has excellent resolution.

[0091] Figure 5 is Figure 1 the schematic diagram of axial chromatic aberration of the industrial lens shown at the optimal object distance. As Figure 5 shown in the figure, the vertical direction in the figure represents the normalization of the 0-field-of-view pupil plane, 0 represents the pupil center, and the vertex in the vertical direction represents the pupil vertex; the horizontal direction is the axial chromatic aberration of different wavelengths (460nm, 530nm, 620nm), with the unit of millimeter (mm). From Figure 5 it can be known that the axial chromatic aberration of the whole pupil of the industrial lens is less than 25μm, and the imaging has excellent clarity.

[0092] Figure 6 is Figure 1 the schematic diagram of lateral chromatic aberration of the industrial lens shown at the optimal object distance. As Figure 6 shown in the figure, the vertical direction in the figure represents the field-of-view angle, 0 represents the field-of-view angle incident parallel to the optical axis, and the vertex in the vertical direction represents the maximum half-field-of-view angle. From Figure 6It can be seen that at each wavelength (460nm, 530nm, 620nm), the vertical chromatic aberration from the central field of view to the edge field of view of the industrial lens is less than 0.6μm, resulting in higher imaging quality.

[0093] In another feasible embodiment, Figure 7 is a schematic structural diagram of another industrial lens provided by an embodiment of the present invention at the optimal object distance. Table 3 details, in another feasible implementation manner, Figure 7 the specific optical physical parameters of the industrial lens shown.

[0094] Table 3 Another Design of Optical Physical Parameters of the Industrial Lens

[0095] Scope of protection Example 2 Lower limit Upper limit TTL / EFL 2.2295 2.1950 2.2300 TTL / DM 3.5497 3.5400 3.7800 EFL 50.6598 50.6500 52.6100 TTL 112.9480 112.9400 115.5400 DM 31.8192 31.7700 33.3200 FOV 22.4183 21.1000 22.4200 F.NO 2.2166 2.2100 2.3100 Vd5 / Vd4 3.8446 2.4100 3.8500 Vd5 / Vd6 3.6617 1.6900 3.6700 Φ4-6 / Φ7-8 -1.1434 -1.1500 -1.0800 Φ11 / Φ12 -0.8436 -0.8900 -0.7200 Φ2-7 / Φ8-10 -0.9104 -1.0300 -0.9100 DISG.MAX -0.0292％ -0.1000％ 0.0000％ ξ1 1.1524 1.1500 1.6800 Φ1 0.0142 0.0140 0.0160 Φ2 -0.0253 -0.0280 -0.0250 Φ3 0.0238 0.0210 0.0240 Φ4 -0.0469 -0.0470 -0.0410 Φ5 0.0370 0.0350 0.0380 Φ6 -0.0450 -0.0460 -0.0420 Φ4-6 -0.0567 -0.0570 -0.0500 Φ7 0.0218 0.0180 0.0220 Φ8 0.0290 0.0270 0.0300 Φ9 0.0370 0.0330 0.0420 Φ10 -0.0512 -0.0540 -0.0440 Φ9-10 -0.0060 -0.0040 -0.0070 Φ11 0.0177 0.0110 0.0180 Φ12 -0.0210 -0.0220 -0.0150

[0096] Table 4 shows the design parameters such as the surface type, radius of curvature, thickness, and material of each lens in another industrial lens corresponding to Table 3.

[0097] Table 4 Another Parameter Design of Each Lens in the Industrial Lens

[0098]

[0099] The industrial lens of this embodiment includes a first lens 10, a first diaphragm 130, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, a second diaphragm 140, a seventh lens 70, an eighth lens 80, a ninth lens 90, a tenth lens 100, an eleventh lens 110, a twelfth lens 120, and a filter glass 150 arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the surface order of each lens. Among them, "1" represents the object side surface of the first lens 10, "2" represents the image side surface of the first lens 10, and so on. "IMG" represents the image plane of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface bends towards the image side, and a negative value represents that the surface bends towards the object side. Among them, "infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light. A space represents that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristic of the material between the current surface and the next surface to light; the semi-aperture represents half of the aperture size of the current surface. When the interval of the 20th surface in the industrial lens of this embodiment is 21.026mm, it can be focused to an object distance of 200mm. When the interval of the 20th surface is 8.648mm, it can be focused to an object distance of 1000mm.

[0100] Figure 8 is Figure 7Schematic diagram of the light fan structure of the industrial lens shown at the optimal object distance. The light fan diagram is one of the most commonly used evaluation methods in modern optical design. As Figure 8 shown, the horizontal axis is the beam aperture and the vertical axis is the lateral aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all the light rays converge at the same point on the image plane. The corresponding interval on the vertical axis of the curve is the maximum dispersion range of the beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths (460nm, 530nm, 620nm) but also represent the magnitude of the lateral chromatic aberration. From Figure 8 it can be seen that the industrial lens shown closely adheres to the horizontal axis at each wavelength (460nm, 530nm, 620nm) in each field of view, indicating that the lateral aberration of each wavelength of the optical system of the industrial lens is well corrected. At the same time, there is no obvious dispersion among the wavelengths, indicating that the system chromatic aberration is also well corrected, thus ensuring that the optical system can meet the high-resolution imaging requirements.

[0101] Figure 9 is Figure 7 Schematic diagram of the field curvature and distortion curve of the industrial lens shown at the optimal object distance. As Figure 9 shown, in the left coordinate system in the figure, the horizontal coordinate represents the magnitude of the field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; where T represents the meridian and S represents the sagittal; from 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 image quality at the center and the image quality at the periphery have a small difference and good consistency; in the right coordinate system, the horizontal coordinate represents the magnitude of the distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit; from Figure 9 it can be seen that the distortion of the industrial lens provided in this embodiment is well corrected, and the optical distortion is less than ±0.1%.

[0102] Figure 10 is Figure 7 Schematic diagram of the MTF of the industrial lens shown at the optimal object distance. The MTF diagram is one of the most commonly used and authoritative evaluation methods in modern optical design. The horizontal axis is the spatial frequency at which the line pairs in the object space are imaged on the image plane by the optical system, with the unit of cycle / mm, and the vertical axis is the modulus value of the optical transfer function. The change trends of the optical transfer function in the meridian (such as T shown in the figure) and sagittal (such as S shown in the figure) directions corresponding to different fields of view (such as 0.00mm, 3.45mm, 5.75mm, 8.05mm, 10.53mm, and 11.50mm shown in the figure) as the spatial frequency increases. The most ideal curve is a straight line that coincides with the system diffraction limit, indicating that the geometric aberration of the light rays at all positions is less than the wave aberration generated by the physical limitation of the system itself and can be ignored. From Figure 10It can be seen that the image quality from the central field of view to the edge field of view of this industrial lens is higher than 0.4 MTF at 180 pl / mm, and the imaging has excellent resolution.

[0103] Figure 11 Yes Figure 7 It is a schematic diagram of the axial chromatic aberration of the industrial lens shown below at the optimal object distance. As Figure 11 shown, the vertical direction in the figure represents the normalization of the 0-field-of-view pupil plane, 0 represents the pupil center, and the vertex in the vertical direction represents the pupil vertex; the horizontal direction is the axial chromatic aberration of different wavelengths (460 nm, 530 nm, 620 nm), with the unit of millimeters (mm). From Figure 11 it can be seen that the axial chromatic aberration of the entire pupil of the industrial lens is less than 35 μm, and the imaging has excellent clarity.

[0104] Figure 12 Yes Figure 7 It is a schematic diagram of the lateral chromatic aberration of the industrial lens shown below at the optimal object distance. As Figure 12 shown, the vertical direction in the figure represents the field angle, 0 represents the field angle incident parallel to the optical axis, and the vertex in the vertical direction represents the maximum semi-field angle. From Figure 12 it can be seen that at each wavelength (460 nm, 530 nm, 620 nm), the lateral chromatic aberration from the central field of view to the edge field of view of the industrial lens is less than 0.7 μm, resulting in higher imaging quality.

[0105] In another feasible embodiment, Figure 13 It is a schematic structural diagram of another industrial lens provided by an embodiment of the present invention at the optimal object distance. Table 5, in another feasible implementation manner, details Figure 13 the specific optical physical parameters of the industrial lens shown below.

[0106] Table 5 Another optical physical parameter design of the industrial lens

[0107] Scope of protection Example 3 Lower limit Upper limit TTL / EFL 2.1962 2.1950 2.2300 TTL / DM 3.7738 3.5400 3.7800 EFL 52.6061 50.6500 52.6100 TTL 115.5340 112.9400 115.5400 DM 33.3162 31.7700 33.3200 FOV 21.1082 21.1000 22.4200 F.NO 2.3015 2.2100 2.3100 Vd5 / Vd4 2.4164 2.4100 3.8500 Vd5 / Vd6 1.6997 1.6900 3.6700 Φ4-6 / Φ7-8 -1.0883 -1.1500 -1.0800 Φ11 / Φ12 -0.7275 -0.8900 -0.7200 Φ2-7 / Φ8-10 -1.0270 -1.0300 -0.9100 DISG.MAX -0.0273％ -0.1000％ 0.0000％ ξ1 1.5157 1.1500 1.6800 Φ1 0.0159 0.0140 0.0160 Φ2 -0.0278 -0.0280 -0.0250 Φ3 0.0216 0.0210 0.0240 Φ4 -0.0414 -0.0470 -0.0410 Φ5 0.0352 0.0350 0.0380 Φ6 -0.0433 -0.0460 -0.0420 Φ4-6 -0.0508 -0.0570 -0.0500 Φ7 0.0211 0.0180 0.0220 Φ8 0.0269 0.0270 0.0300 Φ9 0.0338 0.0330 0.0420 Φ10 -0.0444 -0.0540 -0.0440 Φ9-10 -0.0045 -0.0040 -0.0070 Φ11 0.0117 0.0110 0.0180 Φ12 -0.0160 -0.0220 -0.0150

[0108] Table 6 shows the design parameters such as the surface type, radius of curvature, thickness, and material of each lens in another industrial lens corresponding to Table 5.

[0109] Table 6 Another parameter design of each lens in the industrial lens

[0110]

[0111] The industrial lens of this embodiment includes a first lens 10, a first aperture 130, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, a second aperture 140, a seventh lens 70, an eighth lens 80, a ninth lens 90, a tenth lens 100, an eleventh lens 110, a twelfth lens 120, and a filter glass 150, which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the surface order of each lens. Among them, "1" represents the object side surface of the first lens 10, "2" represents the image side surface of the first lens 10, and so on. "IMG" represents the image plane of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface bends towards the image side, and a negative value represents that the surface bends towards the object side. Among them, "infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light. A space represents that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light. A space represents that the current position is air; the semi-aperture represents half of the aperture size of the current surface. When the interval of the 20th surface in the industrial lens of this embodiment is 25.836 mm, it can be focused on an object distance of 200 mm. When the interval of the 20th surface is 12.016 mm, it can be focused on an object distance of 1000 mm.

[0112] Figure 14 Yes Figure 13 Figure 6 shows a schematic diagram of the ray fan structure of the industrial lens at the optimal object distance. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. As Figure 14 shown, the abscissa is the beam aperture and the ordinate is the lateral aberration. The most ideal curve is a straight line that coincides with the abscissa, indicating that all rays converge at the same point on the image plane. The corresponding interval on the ordinate of the curve is the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths (460 nm, 530 nm, 620 nm) but also represent the magnitude of the lateral chromatic aberration. As Figure 14 can be seen, the industrial lens closely approaches the abscissa at each wavelength (460 nm, 530 nm, 620 nm) in each field of view, indicating that the lateral aberration of each wavelength of the optical system of the industrial lens is well corrected. At the same time, there is no obvious dispersion among the wavelengths, indicating that the system chromatic aberration is also well corrected, thus ensuring that the optical system can meet the high-resolution imaging requirements.

[0113] Figure 15 Yes Figure 13 Figure 7 shows a schematic diagram of the field curvature and distortion curve of the industrial lens at the optimal object distance. As Figure 15As shown in the figure, in the left coordinate system of the figure, the horizontal coordinate represents the magnitude of field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without unit; where T represents the meridian and S represents the sagittal; Figure 15 It can be seen that the lens provided in this embodiment is effectively controlled in terms of field curvature, that is, when imaging, the image quality difference between the center and the periphery is small, and the consistency is good; in the right coordinate system, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without unit; Figure 15 It can be seen that the distortion of the industrial lens provided in this embodiment is well corrected, and the optical distortion is less than ±0.1%.

[0114] Figure 16 is Figure 13 The MTF schematic diagram of the industrial lens shown at the best object distance. The MTF diagram is one of the most commonly used and authoritative evaluation methods in modern optical design. The abscissa is the spatial frequency of the line pairs in the object space imaged on the image plane by the optical system, with the unit of cycle / mm, and the ordinate is the modulus value of the optical transfer function. The changing trends of the optical transfer function in the meridian (such as T shown in the figure) and sagittal (such as S shown in the figure) directions corresponding to different fields of view (such as 0.00mm, 3.45mm, 5.75mm, 8.05mm, 10.53mm, and 11.50mm shown in the figure) as the spatial frequency increases. The most ideal curve is a straight line that coincides with the system diffraction limit, indicating that the geometric aberration of the light rays at all positions is less than the wavefront aberration generated by the physical limitation of the system itself and can be ignored. Figure 16 It can be known that the image quality of the industrial lens from the central field of view to the edge field of view at 180 pl / mm is higher than 0.4 MTF, and the imaging has excellent resolution.

[0115] Figure 17 is Figure 13 The schematic diagram of axial chromatic aberration of the industrial lens shown at the best object distance. As Figure 17 shown in the figure, the vertical direction in the figure represents the normalization of the 0-field-of-view pupil plane, 0 represents the pupil center, and the vertex in the vertical direction represents the pupil vertex; the horizontal direction is the axial chromatic aberration of different wavelengths (460nm, 530nm, 620nm), with the unit of millimeter (mm). Figure 17 It can be known that the axial chromatic aberration of the entire pupil of the industrial lens is less than 20μm, and the imaging has excellent clarity.

[0116] Figure 18 is Figure 13 The schematic diagram of lateral chromatic aberration of the industrial lens shown at the best object distance. As Figure 18 shown in the figure, the vertical direction in the figure represents the field angle, 0 represents the field angle incident parallel to the optical axis, and the vertex in the vertical direction represents the maximum semi-field angle. Figure 18It can be seen that at each wavelength (460nm, 530nm, 620nm), the lateral chromatic aberration from the central field of view to the edge field of view of the industrial lens is less than 0.6μm, resulting in higher imaging quality.

[0117] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An industrial lens, characterized in that: include: A focusing lens group and a fixed lens group are arranged in sequence along the optical axis from the object side to the image side; the focusing lens group moves along the optical axis for focusing; The focusing lens group comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an eighth lens with positive focal power, a ninth lens with positive focal power and a tenth lens with negative focal power, which are arranged in sequence along the optical axis from the object side to the image side; The fixed lens group includes an eleventh lens with positive focal length and a twelfth lens with negative focal length, which are arranged in sequence from the object side to the image side along the optical axis; Wherein, the first lens to the twelfth lens are all glass lenses; The maximum value DISG.MAX of the optical distortion of the industrial lens satisfies: |DISG.MAX|≤0.1000%.

2. The industrial lens according to claim 1, characterized in that: The overall focal length EFL of the industrial lens satisfies: 2.1950≤TTL / EFL≤2.2300; Wherein, TTL is the distance from the front end of the first lens to the image plane of the industrial lens.

3. The industrial lens according to claim 1, characterized in that: The shape factor ξ1 of the first lens satisfies: 1.1500≤|ξ1|≤1.6800.

4. 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: 2.4100≤Vd5 / Vd4.

5. The industrial lens according to claim 1, characterized in that: The Abbe number Vd5 of the fifth lens and the Abbe number Vd6 of the sixth lens satisfy: 1.6900≤Vd5 / Vd6.

6. The industrial lens according to claim 1, characterized in that: The total optical power Φ4-6 of the fourth lens to the sixth lens and the total optical power Φ7-8 of the seventh lens to the eighth lens satisfy: -1.1500≤Φ4-6 / Φ7-8≤-1.0800.

7. The industrial lens according to claim 1, characterized in that: The optical power Φ11 of the eleventh lens and the optical power Φ12 of the twelfth lens satisfy: -0.8900≤Φ11 / Φ12≤-0.7200.

8. The industrial lens according to claim 1, characterized in that: The total optical power Φ2-7 of the second lens to the seventh lens and the total optical power Φ8-10 of the eighth lens to the tenth lens satisfy: -1.0300≤Φ2-7 / Φ8-10≤-0.9100.

9. The industrial lens according to claim 1, characterized in that: The maximum effective aperture DM among the effective apertures of the first lens to the twelfth lens satisfies: 3.5400≤TTL / DM≤3.7800; Wherein, TTL is the distance from the front end of the first lens to the image plane of the industrial lens.

10. The industrial lens according to claim 1, characterized in that: The field of view FOV of the industrial lens satisfies: FOV ≥ 21.1000°; and / or, The aperture number F.NO of the industrial lens satisfies: F.NO≤2.3100.

Images