An industrial lens

Abstract

This utility model discloses an industrial lens, including a focusing lens group and a fixed lens group. The position of the focusing lens group can float along the optical axis, while the position of the fixed lens group is fixed. The focusing lens group includes a first lens with positive optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The fixed lens group includes an eighth lens with positive optical power and a ninth lens with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The moving focusing lens group along the optical axis enables focusing at different object distances, while the fixed lens group remains stationary, reducing the impact of focusing at different object distances on resolution and ensuring balanced image quality at various working distances. Furthermore, the reasonable setting of the number of lenses in each lens group and the optical power of the lenses is beneficial for achieving a high-quality imaging performance industrial lens.

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 modern industrial technology, industrial lenses are being used more and more widely, and their specifications are becoming increasingly diversified. Modern industrial technology demands higher and higher precision in inspection, driving lenses towards higher resolutions. Therefore, improving lens resolution and overall image quality, while reducing distortion, are key goals in the current development of industrial lenses. Large-aperture lenses are increasingly favored because a large aperture allows more light to enter the lens, which helps to obtain brighter images in low-light conditions or fast-moving scenes. In low-light conditions, a large aperture can reduce sensitivity and image noise, contributing to clearer images.

[0003] Existing industrial lenses generally have small apertures (usually F2.8 or F4), and existing lenses are not satisfactory in terms of distortion, resolution, and lens size. The inspection effect of many industrial lenses is not ideal, and these lenses generally have the problem of large edge distortion. Therefore, it is necessary to design an industrial lens with a large aperture, high resolution, and low distortion. Utility Model Content

[0004] This invention provides an industrial lens that achieves high image quality imaging performance.

[0005] This utility model embodiment provides an industrial lens, including a focusing lens group and a fixed lens group arranged sequentially along the optical axis from the object plane to the image plane. The position of the focusing lens group can float along the optical axis, and the position of the fixed lens group is fixed.

[0006] The focusing lens group includes a first lens with positive optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane.

[0007] The fixed lens group includes an eighth lens with positive optical power and a ninth lens with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane.

[0008] Optionally, the focusing lens group includes a front focusing group and an aperture stop, wherein the front focusing group is disposed in the optical path before the aperture stop;

[0009] The optical power of the front focusing group is Φ12, and the optical power of the industrial lens is Φ, where -0.25 < Φ12 / Φ < 0.07.

[0010] Optionally, the front focusing group includes the first lens and the second lens;

[0011] The first lens and / or the second lens are meniscus lenses.

[0012] Optionally, the industrial lens further includes an aperture stop, which is disposed in the optical path between the second lens and the third lens;

[0013] The industrial lens has a back focal length of BF, and the combined focal length of the third lens to the ninth lens is f. 后 , of which 0.582 <BF / f 后 <0.679.

[0014] Optionally, the aperture of the second lens object side is D3, and the radius of curvature of the second lens object side side is R3;

[0015] Among them, 0.4 <D3 / R3<0.75。

[0016] Optionally, the third lens and the fourth lens are cemented together, the sixth lens and the seventh lens are cemented together, and the eighth lens and the ninth lens are cemented together.

[0017] The Abbe number of the third lens is vd3, and the Abbe number of the fourth lens is vd4; wherein

[0018] |vd3-vd4|≤22.

[0019] Optionally, the maximum aperture of the fifth lens is SD, and the total length of the industrial lens is TTL;

[0020] Among them, 0.04 <SD / TTL<0.12。

[0021] Optionally, the focusing distance of the industrial lens from near object distance to far object distance is ZOL, and the focal length of the industrial lens is f.

[0022] Among them, 0.268 <ZOL / f<0.325。

[0023] Optionally, the first lens includes a first object-side surface near the object surface and a first image-side surface near the image surface, wherein the first object-side surface is convex and the first image-side surface is concave or convex.

[0024] The second lens includes a second object-side surface near the object plane and a second image-side surface near the image plane, wherein the second object-side surface is convex and the second image-side surface is concave.

[0025] The third lens includes a third object-side surface near the object plane and a third image-side surface near the image plane. The third object-side surface is concave, and the third image-side surface is concave.

[0026] The fourth lens includes a fourth object-side surface near the object plane and a fourth image-side surface near the image plane. The fourth object-side surface is convex, and the fourth image-side surface is convex.

[0027] The fifth lens includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane. The fifth object-side surface is convex, and the fifth image-side surface is convex.

[0028] The sixth lens includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane. The sixth object-side surface is convex, and the sixth image-side surface is either convex or concave.

[0029] The seventh lens includes a seventh object-side surface near the object plane and a seventh image-side surface near the image plane. The seventh object-side surface is either concave or convex, and the seventh image-side surface is concave.

[0030] The eighth lens includes an eighth object-side surface near the object plane and an eighth image-side surface near the image plane. The eighth object-side surface is convex, and the eighth image-side surface is concave.

[0031] The ninth lens includes a ninth object-side surface near the object plane and a ninth image-side surface near the image plane. The ninth object-side surface is convex, and the ninth image-side surface is either convex or concave.

[0032] Optionally, the first lens, the second lens, the third lens, the fourth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all glass spherical lenses;

[0033] The fifth lens is a glass aspherical lens.

[0034] The industrial lens provided in this embodiment features a focusing lens group that can float along the optical axis, ensuring focusing at different working distances and achieving clear imaging at different object distances. Furthermore, the fixed lens group remains stationary, thus reducing the impact of focusing at different object distances on resolution and ensuring balanced image quality across all working distances. Moreover, by adjusting the number of lenses and optical power in each lens group, a high-quality imaging performance industrial lens is achieved.

[0035] 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

[0036] 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.

[0037] Figure 1 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 1 of this utility model;

[0038] Figure 2 This is a point array diagram of an industrial lens at the optimal object distance provided in Embodiment 1 of this utility model;

[0039] Figure 3 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of this utility model;

[0040] Figure 4 This is a schematic diagram of the axial aberration curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of this utility model.

[0041] Figure 5 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 2 of this utility model;

[0042] Figure 6 This is a schematic diagram of a point array of an industrial lens at the optimal object distance, provided in Embodiment 2 of this utility model;

[0043] Figure 7 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of this utility model;

[0044] Figure 8 This is a schematic diagram of the axial aberration curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of this utility model.

[0045] Figure 9 This is a schematic diagram of the structure of an industrial lens at the optimal object distance provided in Embodiment 3 of this utility model;

[0046] Figure 10 This is a point array diagram of an industrial lens at the optimal object distance provided in Embodiment 3 of this utility model;

[0047] Figure 11 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of this utility model;

[0048] Figure 12 This is a schematic diagram of the axial aberration curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of this utility model. Detailed Implementation

[0049] 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.

[0050] Example 1

[0051] Figure 1 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 1 of this utility model, as shown below. Figure 1 As shown, the industrial lens provided in this embodiment of the present invention includes a focusing lens group S1 and a fixed lens group S2 arranged sequentially along the optical axis from the object plane to the image plane. The position of the focusing lens group S1 can float along the optical axis, while the position of the fixed lens group S2 is fixed. The focusing lens group S1 includes a first lens 101 with positive optical power, a second lens 102 with negative optical power, a third lens 103 with negative optical power, a fourth lens 104 with positive optical power, a fifth lens 105 with positive optical power, a sixth lens 106 with positive optical power, and a seventh lens 107 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The fixed lens group S2 includes an eighth lens 108 with positive optical power and a ninth lens 109 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane.

[0052] Specifically, the industrial lens provided in this embodiment includes a focusing lens group S1 and a fixed lens group S2. The focusing lens group S1 can be understood as a lens group whose position changes, while the fixed lens group S2 can be understood as a lens whose position remains fixed. The focusing lens group S1 moves between the object plane and the fixed lens group S2. This positional change of the focusing lens group S1 ensures that the industrial lens can focus at different object distances, guaranteeing clear imaging at various object distances. Specifically, in close-object-distance focusing, the focusing lens group S1 is closer to the object plane; in infinity focusing, the focusing lens group S1 is closer to the fixed lens group S2. Furthermore, since the fixed lens group S2 remains stationary, the aberration changes caused by the forward and backward movement of the focusing lens group S1 at different working distances are mitigated by the fixed lens group S2, thus ensuring balanced image quality at each working distance and guaranteeing image quality.

[0053] Furthermore, the focusing lens group S1 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, and a seventh lens 107, while the fixed lens group S2 includes an eighth lens 108 and a ninth lens 109. That is, the industrial lens includes seven movable focusing lenses. This allows for focusing through the movement of multiple lenses, ensuring good focusing performance. Simultaneously, by keeping two lenses stationary, the influence of the moving lens group S1 on aberrations is reduced, ensuring balanced image quality at various working distances and guaranteeing overall image quality.

[0054] Furthermore, optical power is equal to the difference between the convergence of the beam at the image plane and the convergence of the beam at the object plane, characterizing the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., a surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group). In this embodiment, the first lens 101 is a positive optical power lens, and its positive optical power setting can significantly correct the edge aberrations of the optical imaging system, thereby improving the imaging resolution of the optical system. The second lens 102 and the third lens 103 are both negative optical power lenses, and their negative optical power setting can effectively deflect the outgoing light, which is beneficial for achieving a large image plane design. Lenses 104, 105, and 106 are all positive power lenses, 107 is a negative power lens, 108 is a positive power lens, and 109 is a negative power lens. Lenses 104 through 109 are arranged in a positive-positive-positive-negative-positive-negative pattern, which, with its combination of positive and negative power, is beneficial for aberration correction.

[0055] In summary, the industrial lens provided by this embodiment features a focusing lens group that can float along the optical axis, ensuring focusing at different working distances and achieving clear imaging at different object distances. Furthermore, the fixed lens group remains stationary, reducing the impact of different object distances on resolution and ensuring balanced image quality across all working distances. Moreover, the arrangement of nine lenses with varying optical powers ensures a reasonable number of lenses in the optical system, preventing excessive lens size or excessive aberrations caused by a single lens bearing too much optical power. This approach ensures both miniaturization of the optical system and low imaging aberrations, resulting in high image quality. Furthermore, by rationally configuring the number of lenses and the optical power combination in the focusing lens group S1 and the fixed lens group S2, the imaging quality of the industrial lens is improved, guaranteeing a high-quality imaging performance.

[0056] Based on the above embodiments, the focusing lens group S1 includes a front focusing group and an aperture stop STO. The front focusing group is disposed in the optical path before the aperture stop STO. The optical power of the front focusing group is Φ12, and the optical power of the industrial lens is Φ, where -0.25<Φ12 / Φ<0.07.

[0057] Specifically, setting the aperture stop STO can adjust the propagation direction of the light beam, which helps improve image quality. Furthermore, in this industrial lens, the STO, positioned within the optical system, can limit the beam size and control the amount of light transmitted through the lens, thus allowing for a smaller aperture value and achieving a large aperture. Moreover, the STO is located within the focusing lens group S1, and moves together with it during focusing, ensuring image quality during the focusing process.

[0058] Furthermore, by controlling the optical power of the lens element at the front of the aperture stop, the angle and direction of light rays can be effectively controlled, preventing excessive divergence in the angle of light entering the lens. This reduces off-axis aberrations and improves the image quality of the industrial lens. It also facilitates a smoother transition of light rays at the rear of the lens, resulting in better tolerances for individual lenses and assembly.

[0059] Furthermore, the industrial lens provided in this embodiment may also include a filter 110, which is disposed in the optical path between the ninth lens 109 and the image plane to filter out stray light and improve imaging performance. Further, the optical lens provided in this embodiment may also include a protective glass and an imaging sensor. The protective glass may be disposed on the image-side of the filter, and the imaging sensor may be disposed on the image-side of the protective glass. The optical system is protected by the protective glass, and images are acquired by the imaging sensor, enabling the optical system to perform its normal imaging function.

[0060] Based on the above embodiments, the front focusing group includes a first lens 101 and a second lens 102; the first lens 101 and / or the second lens 102 are meniscus lenses.

[0061] Specifically, the first lens 101 and / or the second lens 102 are meniscus lenses, meaning that the front focusing group contains at least one meniscus lens, which can effectively correct system field curvature. For example... Figure 1 As shown, Figure 1 Taking the example that both the first lens 101 and the second lens 102 are meniscus lenses, this can further correct the field curvature of the system.

[0062] Based on the above embodiments, the industrial lens also includes an aperture stop ST0, which is disposed in the optical path between the second lens 102 and the third lens 103; the back focal length of the industrial lens is BF, and the combined focal length of the third lens 103 to the ninth lens 109 is f. 后 , of which 0.582 <BF / f 后 <0.679.

[0063] Specifically, the above formula defines the correspondence between the lens group after the STO aperture and the optical back focal length of the industrial lens. If the upper limit of this limit is exceeded, the focal length will be short, the off-axis aberrations of the system will increase, and it will be detrimental to image quality improvement. If the lower limit of this limit is exceeded, the back focal length of the system will be too short, which will be detrimental to the installation and replacement of components. Through the constraint of this clause, sufficient back focal length space can be reserved while ensuring image quality and avoiding mechanical interference.

[0064] Based on the above embodiment, the aperture of the object-side surface of the second lens 102 is D3, and the radius of curvature of the object-side surface of the second lens 102 is R3; wherein, 0.4 <D3 / R3<0.75。

[0065] Specifically, by controlling the ratio between the aperture of the object-side surface of the second lens 102 and the radius of curvature of its surface, the shape of the second lens 102 can be controlled, thereby constraining its ability to refract light, reducing the occurrence of large light refraction angles, and having a beneficial impact on the control of aberrations in industrial lenses, thus contributing to the improvement of image quality in the optical system. Furthermore, by limiting the ratio between the aperture of the object-side surface of the second lens 102 and the radius of curvature of its surface, the manufacturability of the second lens 102 can be improved.

[0066] Based on the above embodiments, the third lens 103 and the fourth lens 104 are cemented together, the sixth lens 106 and the seventh lens 107 are cemented together, and the eighth lens 108 and the ninth lens 109 are cemented together; the Abbe number of the third lens 103 is vd3, and the Abbe number of the fourth lens 104 is vd4; wherein |vd3-vd4|≤22.

[0067] Specifically, different lens cementation settings can be understood as the image-side surface of the preceding lens and the object-side surface of the following lens being bonded together in the optical path, possessing the same surface shape. For example... Figure 1 As shown, the third lens 103 and the fourth lens 104 are cemented together, which can be understood as the image-side of the third lens 103 being bonded to the object-side of the fourth lens 104. Similarly, the sixth lens 106 and the seventh lens 107 are cemented together, meaning the image-side of the sixth lens 106 is bonded to the object-side of the seventh lens 107. Likewise, the eighth lens 108 and the ninth lens 109 are cemented together, with the image-side of the eighth lens 108 bonded to the object-side of the ninth lens 109. In other words, the focusing lens group S1 includes two sets of cemented lens groups, and the fixed lens group S2 includes one set of cemented lens groups.

[0068] A cemented lens can be used to minimize or eliminate chromatic aberration. Using a cemented lens in an industrial lens can improve image quality and reduce the reflection loss of light energy, thereby enhancing the clarity of the lens imaging. Additionally, the cementing of the lenses eliminates the air gap between the two lenses, making the overall optical system compact and meeting the requirement of system miniaturization. Moreover, the cementing of the lenses reduces the sensitivity to tolerances such as tilt / eccentricity generated during the assembly of the lens unit.

[0069] Furthermore, the third lens 103 and the fourth lens 104 can be cemented by being supported by a spacer or can be cemented by glue bonding; the third lens 103 and the fourth lens 104 can be cemented by being supported by a spacer or can be cemented by glue bonding; the sixth lens 106 and the seventh lens 107 can be cemented by being supported by a spacer or can be cemented by glue bonding; the eighth lens 108 and the ninth lens 109 can be cemented by being supported by a spacer or can be cemented by glue bonding.

[0070] Furthermore, the Abbe number vd3 of the third lens 103 and the Abbe number vd4 of the fourth lens 104 satisfy |vd3 - vd4| ≤ 22. By controlling the chromatic aberration of the cemented lenses, the chromatic aberration generated by other lenses in the system can be effectively offset, ensuring that the overall chromatic aberration of the system is within a small range.

[0071] Based on the above embodiments, the maximum aperture of the fifth lens 105 is SD, and the total length of the industrial lens is TTL; wherein, 0.04 < SD / TTL < 0.12. By controlling the ratio between the maximum aperture of the fifth lens 105 and the total length of the industrial lens, the size of the light passing aperture of the fifth lens 105 can be controlled, avoiding an overly large lens aperture, effectively limiting the weight of the optical system, and further avoiding an overly long total length of the lens due to an overly large aperture, which is beneficial for reducing the lens size.

[0072] Based on the above embodiments, the moving distance of the focusing group of the industrial lens from the near object distance to the far object distance is ZOL, and the focal length of the industrial lens is f; wherein, 0.268 < ZOL / f < 0.325. This limiting relationship restricts the ratio range of the moving distance of the focusing lens group S1 to the focal length of the optical system. If it exceeds the upper limit of this range, the moving range of the focusing lens group S1 is too large, making it difficult to compress the total length of the lens; if it exceeds the lower limit of this range, the moving range of the focusing group is too small, and it is difficult to achieve the focusing process from infinity to the close distance, and the image quality at the close distance cannot be guaranteed. Reasonably limiting the ratio range of the moving distance of the focusing lens group S1 to the focal length of the optical system can achieve a smaller overall optical length and ensure the smooth realization of the focusing process.

[0073] Based on the above embodiments, the first lens 101 includes a first object-side surface near the object plane and a first image-side surface near the image plane, wherein the first object-side surface is convex and the first image-side surface is concave or convex; the second lens 102 includes a second object-side surface near the object plane and a second image-side surface near the image plane, wherein the second object-side surface is convex and the second image-side surface is concave; the third lens 103 includes a third object-side surface near the object plane and a third image-side surface near the image plane, wherein the third object-side surface is concave and the third image-side surface is concave; the fourth lens 104 includes a fourth object-side surface near the object plane and a fourth image-side surface near the image plane, wherein the fourth object-side surface is convex and the fourth image-side surface is convex; the fifth lens 105 includes a fifth object-side surface near the object plane and a second image-side surface near the image plane. The fifth image-side surface on the image plane side is convex, and the fifth image-side surface is convex; the sixth lens 106 includes a sixth object-side surface near the object plane side and a sixth image-side surface near the image plane side, the sixth object-side surface is convex, and the sixth image-side surface is either convex or concave; the seventh lens 107 includes a seventh object-side surface near the object plane side and a seventh image-side surface near the image plane side, the seventh object-side surface is either concave or convex, and the seventh image-side surface is concave; the eighth lens 108 includes an eighth object-side surface near the object plane side and an eighth image-side surface near the image plane side, the eighth object-side surface is convex, and the eighth image-side surface is concave; the ninth lens 109 includes a ninth object-side surface near the object plane side and a ninth image-side surface near the image plane side, the ninth object-side surface is convex, and the ninth image-side surface is either convex or concave.

[0074] Specifically, the object-side surface of a lens can be understood as the surface of the lens closest to the object plane, and the image-side surface of a lens can be understood as the surface of the lens closest to the image plane.

[0075] The object side of the first lens 101 is convex, and the image side is concave or convex. It can be understood that the object side of the first lens 101 convexes towards the object surface near the optical axis, and the image side is concave or convex towards the image surface near the optical axis. In other words, the first lens 101 is a lens with a convex-concave structure or a biconvex structure. Figure 1 The structure shown is illustrated using the first lens 101 as an example of a convex-concave structure lens.

[0076] The object side of the second lens 102 is convex, and the image side is concave. This can be understood as the object side of the second lens 102 convex towards the object surface at the near-optical axis position, and the image side concave towards the image surface at the near-optical axis position. In other words, the second lens 102 is a lens with a convex-concave structure.

[0077] The object side of the third lens 103 is concave, and the image side is also concave. This can be understood as the object side of the third lens 103 being concave towards the object plane near the optical axis, and the image side being concave towards the image plane near the optical axis. In other words, the third lens 103 is a lens with a double concave structure.

[0078] The object-side surface of the fourth lens 104 is convex, and the image-side surface is also convex. This can be understood as the object-side surface of the fourth lens 104 convex towards the object surface near the optical axis, and the image-side surface convex towards the image surface near the optical axis. In other words, the fourth lens 104 is a lens with a biconvex structure.

[0079] The object-side surface of the fifth lens 105 is convex, and the image-side surface is also convex. This can be understood as the object-side surface of the fifth lens 105 convex towards the object surface near the optical axis, and the image-side surface convex towards the image surface near the optical axis. In other words, the fifth lens 105 is a lens with a biconvex structure.

[0080] The object side of the sixth lens 106 is convex, and the image side is either convex or concave. This can be understood as the object side of the sixth lens 106 convex towards the object surface near the optical axis, and the image side convex or concave towards the image surface near the optical axis. In other words, the sixth lens 106 can be a lens with a biconvex structure or a convex-concave structure. Figure 1 The structure shown is illustrated using the sixth lens 106 as an example of a biconvex lens.

[0081] The object side of the seventh lens 107 is concave or convex, and the image side is concave. This can be understood as the object side of the seventh lens 107 being concave or convex toward the object surface near the optical axis, and the image side being concave toward the image surface near the optical axis. In other words, the seventh lens 107 can be a lens with a double concave structure or a convex-concave structure. Figure 1 The structure shown is illustrated using the seventh lens 107 as an example of a biconcave lens.

[0082] The object side of the eighth lens 108 is convex, and the image side is concave. This can be understood as the object side of the eighth lens 108 convex towards the object surface near the optical axis, and the image side concave towards the image surface near the optical axis. In other words, the eighth lens 108 is a lens with a convex-concave structure.

[0083] The object side of the ninth lens 109 is convex, and the image side is concave or convex. It can be understood that the object side of the ninth lens 109 convexes towards the object surface near the optical axis, and the image side is concave or convex towards the image surface near the optical axis. In other words, the ninth lens 109 can be a lens with a convex-concave structure or a biconvex structure. Figure 1 The structure shown is illustrated using the ninth lens 109 as an example of a convex-concave structure lens.

[0084] By properly setting the concave and convex surfaces of each lens, the light emission angle of each lens can be modulated. Furthermore, for cemented lenses, it is possible to cement at least two adjacent lenses together. On the other hand, it can also reduce the spacing between adjacent lenses, which is beneficial for achieving small-volume industrial lens designs.

[0085] Based on the above embodiments, the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the sixth lens 106, the seventh lens 107, the eighth lens 108 and the ninth lens 109 are all glass spherical lenses; the fifth lens 105 is a glass aspherical lens.

[0086] Specifically, by setting the fifth lens 105 as an aspherical lens, field aberrations can be optimized, field curvature and distortion can be corrected, resulting in higher system resolution and improved imaging performance. Furthermore, the first lens 101, second lens 102, third lens 103, fourth lens 104, sixth lens 106, seventh lens 107, eighth lens 108, and ninth lens 109 are all glass spherical lenses. Using an optical structure of eight glass spherical lenses and one glass aspherical lens better corrects chromatic aberration and aberrations, improves image quality, and reduces processing costs, achieving higher cost-effectiveness. The materials used for the glass spherical lenses and glass aspherical lenses are various types of glass known to those skilled in the art; this embodiment of the invention does not elaborate on or limit their application.

[0087] As a feasible implementation method, the parameters of each lens in the industrial lens will be explained next.

[0088] Table 1. Optical design values ​​for an industrial lens in Example 1.

[0089] Scope of protection Example 1 lower limit upper limit Φ12 / Φ -0.157 -0.25 0.07 <![CDATA[BF / f 后 ]]> 0.649 0.582 0.679 D3 / R3 0.604 0.4 0.75 |vd3-vd4| 11.3 22 SD / TTL <![CDATA[ 0 .089]]> 0.04 0.12 ZOL / f 0.286 0.268 0.325

[0090] Table 2 Design values ​​of optical physical parameters for industrial lenses

[0091]

[0092] The surface numbers in Table 2 are assigned according to the surface sequence of each lens. "0" represents the object surface, "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image surface, and a negative value indicates that the surface bends towards the object surface. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates 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.

[0093] Table 3. Design values ​​for the aspherical coefficient of industrial lenses.

[0094] Face number A B C D 9 1.936786E-04 -2.142424E-06 2.358758E-08 -1.183485E-10 10 -6.873309E-05 1.218699E-06 -1.057988E-08 6.160131E-11

[0095] Where 1.936786E-04 represents 1.936786 * 10-4 All other parameters can be represented in this way.

[0096] Furthermore, the aspherical conic coefficients can be defined using the following aspherical formula, but are not limited to the following representations:

[0097]

[0098] Where z is the axial sagitta in the Z-direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the conic coefficient; and AD are the coefficients of the 4th, 6th, 8th, and 10th order terms of the aspherical polynomial.

[0099] Table 4. One design value for focusing interval.

[0100] Object distance Object distance 100mm Object distance infinity Focusing interval 8.555mm 1.4499mm

[0101] Figure 2 This is a schematic diagram of an industrial lens at the optimal object distance, provided in Embodiment 1 of this utility model. The several spot patterns in the diagram represent the distribution of intersection points between different light rays and the image plane in several given fields of view. Many light rays emanating from a single point, after passing through the optical system, will no longer converge at a single point due to aberrations, forming a diffuse pattern scattered over a certain range. For the optical system, a smaller spot size is better; that is, the smaller the value in the table, the better the image quality. Figure 2 As can be seen, there is no significant dispersion in the wavelengths, and the blur spot is also small, indicating that the system aberrations have been well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0102] Figure 3 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of this utility model. In the coordinate system on the left side of the figure, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents the meridion and S represents the sagitta; Figure 3 As can be seen, the lens provided in this embodiment effectively controls field curvature, meaning that the difference in image quality between the center and the periphery is small during imaging. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; 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, resulting in minimal imaging distortion.

[0103] Figure 4This is a schematic diagram of the axial aberration curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of this utility model. The horizontal axis represents the focal position, and the vertical axis represents the normalized pupil size. Each line represents a different wavelength, used to analyze the focusing differences of light of different wavelengths. The difference in focal position of light of different wavelengths reflects the dispersion characteristics of the optical system. If light of different wavelengths is focused at the same position, it indicates that the dispersion is small; conversely, it indicates that the dispersion is large. As can be seen from the figure, the focal shift variation of different wavelengths is within 20 micrometers, and the system chromatic aberration is small.

[0104] In summary, the industrial lens provided by this embodiment of the invention adopts an 8G+1GM structure using glass spherical and aspherical surfaces. Through the combination of lens materials and the rational allocation of the optical power of each element, it achieves an industrial lens design that can balance large aperture, low distortion, and high resolution. The aperture is F2, and the optical distortion is ≤0.5%.

[0105] Example 2

[0106] Figure 5 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 2 of this utility model, as shown below. Figure 5 As shown, the industrial lens provided in Embodiment 2 of this utility model includes a focusing lens group S1 and a fixed lens group S2 arranged sequentially along the optical axis from the object plane to the image plane. The position of the focusing lens group S1 can float along the optical axis, while the position of the fixed lens group S2 is fixed. The focusing lens group S1 includes a first lens 101 with positive optical power, a second lens 102 with negative optical power, a third lens 103 with negative optical power, a fourth lens 104 with positive optical power, a fifth lens 105 with positive optical power, a sixth lens 106 with positive optical power, and a seventh lens 107 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The fixed lens group S2 includes an eighth lens 108 with positive optical power and a ninth lens 109 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane.

[0107] The difference between Embodiment 2 and Embodiment 1 is that the image-side surface of the first lens is convex; the image-side surface of the sixth lens is concave; the object-side surface of the seventh lens is convex; and the image-side surface of the ninth lens is convex.

[0108] Other parameters are the same as in Example 1, and will not be repeated here.

[0109] As another feasible implementation method, the specific parameters in industrial lenses are explained below.

[0110] Table 5. Optical design values ​​for an industrial lens in Example 2.

[0111] Scope of protection Example 2 lower limit upper limit Φ12 / Φ 0.025 -0.25 0.07 <![CDATA[BF / f 后 ]]> 0.659 0.582 0.679 D3 / R3 0.743 0.4 0.75 |vd3-vd4| 10.9 22 SD / TTL <![CDATA[ 0 .102]]> 0.04 0.12 ZOL / f 0.306 0.268 0.325

[0112] Table 6 Design values ​​of optical physical parameters for industrial lenses

[0113]

[0114]

[0115] The surface numbers in Table 6 are assigned according to the surface sequence of each lens. "0" represents the object surface, "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image surface, and a negative value indicates that the surface bends towards the object surface. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates 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.

[0116] Table 7. Design values ​​for the aspherical coefficient of industrial lenses.

[0117] Face number A B C D 9 1.900042E-04 -2.198989E-06 2.513360E-08 -1.710776E-10 10 -1.000574E-04 1.420329E-06 -1.050104E-08 -1.974348E-12

[0118] Wherein, 1.900042E-04 represents 1.900042 * 10 -4 All other parameters can be represented in this way.

[0119] Furthermore, the aspherical conic coefficients can be defined using the following aspherical formula, but are not limited to the following representations:

[0120]

[0121] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the conic coefficient; and AG are the coefficients of the 4th, 6th, 8th, and 10th order terms of the aspherical polynomial.

[0122] Table 8. One design value for focus interval.

[0123] Object distance Object distance 100mm Object distance infinity Focusing interval 10.2625mm 2.5479mm

[0124] Figure 6 This is a schematic diagram of an industrial lens at the optimal object distance, provided in Embodiment 2 of this utility model. The several spot patterns in the diagram represent the distribution of intersection points between different light rays and the image plane in several given fields of view. Many light rays emanating from a single point, after passing through the optical system, will no longer converge at a single point due to aberrations, forming a diffuse pattern scattered over a certain range. For the optical system, a smaller spot size is better; that is, the smaller the value in the table, the better the image quality. Figure 6As can be seen, there is no significant dispersion in the wavelengths, and the blur spot is also small, indicating that the system aberrations have been well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0125] Figure 7 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of this utility model. In the coordinate system on the left side of the figure, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents the meridion and S represents the sagitta; Figure 7 As can be seen, the lens provided in this embodiment effectively controls field curvature, meaning that the difference in image quality between the center and the periphery is small during imaging. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; 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, resulting in minimal imaging distortion.

[0126] Figure 8 This is a schematic diagram of the axial aberration curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of this utility model. The horizontal axis represents the focal position, and the vertical axis represents the normalized pupil size. Each line represents a different wavelength, used to analyze the focusing differences of light of different wavelengths. The difference in focal position of light of different wavelengths reflects the dispersion characteristics of the optical system. If light of different wavelengths is focused at the same position, it indicates that the dispersion is small; conversely, it indicates that the dispersion is large. As can be seen from the figure, the focal shift variation of different wavelengths is within 22 micrometers, and the system chromatic aberration is small.

[0127] In summary, the industrial lens provided by this embodiment of the invention adopts an 8G+1GM structure using glass spherical and aspherical surfaces. Through the combination of lens materials and the rational allocation of the optical power of each element, it achieves an industrial lens design that can balance large aperture, low distortion, and high resolution. The aperture is F2, and the optical distortion is ≤0.5%.

[0128] Example 3

[0129] Figure 9 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 3 of this utility model, as shown below. Figure 9As shown, the industrial lens provided in Embodiment 3 of this utility model includes a focusing lens group S1 and a fixed lens group S2 arranged sequentially along the optical axis from the object plane to the image plane. The position of the focusing lens group S1 can float along the optical axis, while the position of the fixed lens group S2 is fixed. The focusing lens group S1 includes a first lens 101 with positive optical power, a second lens 102 with negative optical power, a third lens 103 with negative optical power, a fourth lens 104 with positive optical power, a fifth lens 105 with positive optical power, a sixth lens 106 with positive optical power, and a seventh lens 107 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The fixed lens group S2 includes an eighth lens 108 with positive optical power and a ninth lens 109 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane.

[0130] Other parameters are the same as in Example 1, and will not be repeated here.

[0131] As another feasible implementation method, the specific parameters in industrial lenses are explained below.

[0132] Table 9. Optical design values ​​for an industrial lens in Example 3.

[0133] Scope of protection Example 3 lower limit upper limit Φ12 / Φ -0.069 -0.25 0.07 <![CDATA[BF / f 后 ]]> 0.63 0.582 0.679 D3 / R3 0.658 0.4 0.75 |vd3-vd4| 15.5 22 SD / TTL <![CDATA[ 0 .104]]> 0.04 0.12 ZOL / f 0.303 0.268 0.325

[0134] Table 10 Design values ​​of optical physical parameters for industrial lenses

[0135]

[0136] The surface numbers in Table 10 are assigned according to the surface sequence of each lens. "0" represents the object surface, "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image surface, and a negative value indicates that the surface bends towards the object surface. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates 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.

[0137] Table 11 Design values ​​for the aspherical coefficient of industrial lenses

[0138] Face number A B C D 9 1.596088E-04 -2.267743E-06 2.304404E-08 -2.177286E-10 10 -7.946132E-05 7.459463E-07 -9.235519E-09 -3.581714E-11

[0139] Where 1.596088E-04 represents 1.596088 * 10 -4 All other parameters can be represented in this way.

[0140] Furthermore, the aspherical conic coefficients can be defined using the following aspherical formula, but are not limited to the following representations:

[0141]

[0142] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the conic coefficient; and AG are the coefficients of the 4th, 6th, 8th, and 10th order terms of the aspherical polynomial.

[0143] Table 12. One design value for focusing interval.

[0144] Object distance Object distance 100mm Object distance infinity Focusing interval 9.1274mm 1.5962mm

[0145] Figure 10 This is a schematic diagram of an industrial lens at the optimal object distance, provided in Embodiment 3 of this utility model. The several spot patterns in the diagram represent the distribution of intersection points between different light rays and the image plane in several given fields of view. Many light rays emanating from a single point, after passing through the optical system, will no longer converge at a single point due to aberrations, forming a diffuse pattern scattered over a certain range. For the optical system, a smaller spot size is better; that is, the smaller the value in the table, the better the image quality. Figure 10 As can be seen, there is no significant dispersion in the wavelengths, and the blur spot is also small, indicating that the system aberrations have been well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0146] Figure 11 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of this utility model. In the coordinate system on the left side of the figure, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents the meridion and S represents the sagitta; Figure 11 As can be seen, the lens provided in this embodiment effectively controls field curvature, meaning that the difference in image quality between the center and the periphery is small during imaging. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; 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, resulting in minimal imaging distortion.

[0147] Figure 12 This is a schematic diagram of the axial aberration curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of this utility model. The horizontal axis represents the focal position, and the vertical axis represents the normalized pupil size. Each line represents a different wavelength, used to analyze the focusing differences of light of different wavelengths. The difference in focal position of light of different wavelengths reflects the dispersion characteristics of the optical system. If light of different wavelengths is focused at the same position, it indicates that the dispersion is small; conversely, it indicates that the dispersion is large. As can be seen from the figure, the focal shift variation of different wavelengths is within 24 micrometers, and the system chromatic aberration is small.

[0148] In summary, the industrial lens provided by this embodiment of the invention adopts an 8G+1GM structure using glass spherical and aspherical surfaces. Through the combination of lens materials and the rational allocation of the optical power of each element, it achieves an industrial lens design that can balance large aperture, low distortion, and high resolution. The aperture is F2, and the optical distortion is ≤0.5%.

[0149] 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 focusing lens group and a fixed lens group arranged sequentially from the object plane to the image plane along the optical axis. The position of the focusing lens group can float along the optical axis, while the position of the fixed lens group is fixed. The focusing lens group includes a first lens with positive optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The fixed lens group includes an eighth lens with positive optical power and a ninth lens with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane.

2. The industrial lens according to claim 1, characterized in that, The focusing lens group includes a front focusing group and an aperture stop, wherein the front focusing group is disposed in the optical path before the aperture stop; The optical power of the front focusing group is Φ12, and the optical power of the industrial lens is Φ, where -0.25 < Φ12 / Φ < 0.

07.

3. The industrial lens according to claim 2, characterized in that, The front focusing group includes the first lens and the second lens; The first lens and / or the second lens are meniscus lenses.

4. The industrial lens according to claim 1, characterized in that, The industrial lens also includes an aperture stop, which is disposed in the optical path between the second lens and the third lens; The industrial lens has a back focal length of BF, and the combined focal length of the third lens to the ninth lens is f. 后 , of which 0.582 <BF / f 后 <0.

679.

5. The industrial lens according to claim 1, characterized in that, The aperture of the second lens object side is D3, and the radius of curvature of the second lens object side side is R3; Among them, 0.4 <D3 / R3<0.75。 6. The industrial lens according to claim 1, characterized in that, The third lens and the fourth lens are cemented together, the sixth lens and the seventh lens are cemented together, and the eighth lens and the ninth lens are cemented together. The Abbe number of the third lens is vd3, and the Abbe number of the fourth lens is vd4; wherein |vd3-vd4|≤22.

7. The industrial lens according to claim 1, characterized in that, The maximum aperture of the fifth lens is SD, and the total length of the industrial lens is TTL. Among them, 0.04 <SD / TTL<0.12。 8. The industrial lens according to claim 1, characterized in that, The distance the industrial lens moves from near object distance to far object distance is ZOL, and the focal length of the industrial lens is f. Among them, 0.268 <ZOL / f<0.325。 9. The industrial lens according to claim 1, characterized in that, The first lens includes a first object-side surface near the object surface and a first image-side surface near the image surface. The first object-side surface is convex, and the first image-side surface is concave or convex. The second lens includes a second object-side surface near the object plane and a second image-side surface near the image plane, wherein the second object-side surface is convex and the second image-side surface is concave. The third lens includes a third object-side surface near the object plane and a third image-side surface near the image plane. The third object-side surface is concave, and the third image-side surface is concave. The fourth lens includes a fourth object-side surface near the object plane and a fourth image-side surface near the image plane. The fourth object-side surface is convex, and the fourth image-side surface is convex. The fifth lens includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane. The fifth object-side surface is convex, and the fifth image-side surface is convex. The sixth lens includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane. The sixth object-side surface is convex, and the sixth image-side surface is either convex or concave. The seventh lens includes a seventh object-side surface near the object plane and a seventh image-side surface near the image plane. The seventh object-side surface is either concave or convex, and the seventh image-side surface is concave. The eighth lens includes an eighth object-side surface near the object plane and an eighth image-side surface near the image plane. The eighth object-side surface is convex, and the eighth image-side surface is concave. The ninth lens includes a ninth object-side surface near the object plane and a ninth image-side surface near the image plane. The ninth object-side surface is convex, and the ninth image-side surface is either convex or concave.

10. The industrial lens according to claim 1, characterized in that, The first lens, the second lens, the third lens, the fourth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all glass spherical lenses; The fifth lens is a glass aspherical lens.

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