Industrial line scanning lens

Abstract

The utility model discloses an industrial line scanning lens which comprises a first lens group, a second lens group and a third lens group. The positions of the first lens group and the third lens group are fixed, and the position of the second lens group is floatable; the focal power of the first lens group is negative, and the first lens group at least comprises a first lens with negative focal power; the focal power of the second lens group is positive, and the second lens group at least comprises a fourth lens with negative focal power, a fifth lens with positive focal power, a sixth lens with positive focal power, a seventh lens with negative focal power and an eighth lens with positive focal power; and the third lens group has negative focal power and comprises a ninth lens with negative focal power. The second lens group moves along the optical axis to realize focusing of different object distances, and the first lens group and the third lens group are fixed to weaken the influence of the moving process of the focusing lens group on aberration so as to ensure that the image quality of each working distance is balanced. And the number of the lenses in each lens group and the focal power of each lens are reasonably set, so that the small-distortion scanning lens can be realized.

Description

Technical Field

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

[0002] With the development of industrial automation, visual inspection has become a crucial component. However, most existing line scan lenses are currently large and suffer from significant distortion. As demand increases, the requirements for line scan lenses are becoming increasingly stringent. Therefore, designing high-performance line scan lenses holds great market potential. Utility Model Content

[0003] This invention provides an industrial line scan lens that achieves low distortion and high image quality imaging performance within an object distance range of 200-800mm.

[0004] This utility model embodiment provides an industrial line scan lens, including a first lens group, a second lens group, and a third lens group arranged sequentially along the optical axis from the object plane to the image plane; the positions of the first lens group and the third lens group are fixed, while the position of the second lens group can float along the optical axis.

[0005] The optical power of the first lens group is negative, the optical power of the second lens group is positive, and the optical power of the third lens group is negative.

[0006] The industrial line scan lens further includes a first lens with negative 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 positive optical power, a seventh lens with negative optical power, 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.

[0007] The first lens group includes at least the first lens; the second lens group includes at least the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens; and the third lens group includes the ninth lens.

[0008] Optionally, the first lens group includes a first lens, and the second lens group includes a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens;

[0009] Alternatively, the first lens group may include a first lens, a second lens, and a third lens; the second lens group may include a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0010] Optionally, the optical power of the first lens group is Φa, the optical power of the second lens group is Φb, and the optical power of the third lens group is Φc.

[0011] Among them, 0.9128≤|(Φa-Φb) / (Φc-Φb)|≤1.0145;

[0012] 0.8058≤|Φa / Φc|≤1.0369.

[0013] Optionally, the second lens and the third lens are cemented together, or the second lens and the third lens are independently disposed;

[0014] The industrial line scan lens also includes an aperture stop, which is disposed in the optical path between the fifth lens and the sixth lens;

[0015] The fourth lens and the fifth lens are cemented together, and the sixth lens and the seventh lens are cemented together.

[0016] Optionally, the optical power of the second lens is Φ2, the optical power of the third lens is Φ3, the optical power of the cemented lens formed by the fourth and fifth lenses is Φ45, the optical power of the cemented lens formed by the sixth and seventh lenses is Φ67, and the optical power of the eighth lens is Φ8.

[0017] Where -0.9110≤Φ2 / Φ3≤-0.6939;

[0018] -16.8636≤Φ8 / (Φ45+Φ67)≤-5.5830.

[0019] Optionally, the first lens has a refractive index of nd1 and an Abbe number of vd1; the second lens has a refractive index of nd2 and an Abbe number of vd2; and the third lens has a refractive index of nd3 and an Abbe number of vd3.

[0020] Among them, 1.6166≤nd1≤1.7119, 27.4351≤vd1≤52.0986;

[0021] 1.4490≤nd2≤1.7036、35.0075≤vd2≤85.0000;

[0022] 1.7960≤nd3≤2.0566;27.0256≤vd3≤47.0051;

[0023] Optionally, the Abbe number of the fourth lens is vd4, the Abbe number of the fifth lens is nd5, the refractive index of the sixth lens is nd6, the refractive index of the seventh lens is nd7, and the refractive index of the eighth lens is nd8.

[0024] Among them, 73.9234≤vd4+vd5≤123.5863;

[0025] 0.0909≤(nd7-nd6) / nd8≤0.1420.

[0026] Optionally, the focal length of the industrial line scan lens at an object distance of 400mm is f, the full field of view of the industrial line scan lens is w, the total optical length of the industrial line scan lens is TTL, and the back focal length of the industrial line scan lens is BFL.

[0027] Among them, 5.7930≤(f / w)*10≤6.0115;

[0028] 2.7152≤TTL / f≤2.9262;

[0029] 0.1204 <BFL / TTL<0.1869。

[0030] 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.

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

[0032] 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 either convex or concave, and the third image-side surface is convex.

[0033] 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 concave.

[0034] 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.

[0035] 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 either concave or convex, and the sixth image-side surface is convex.

[0036] 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 concave, and the seventh image-side surface is concave.

[0037] 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 concave, and the eighth image-side surface is convex.

[0038] 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 concave, and the ninth image-side surface is convex.

[0039] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens all include glass spherical lenses.

[0040] The industrial line scan lens provided in this embodiment of the utility model is configured such that the second lens group can float along the optical axis, ensuring that focusing can be achieved at different working distances and clear imaging at different object distances. Furthermore, the first and third lens groups are fixed, which can reduce the impact of the movement of the second lens group on aberrations and ensure that the image quality at each working distance is balanced. Moreover, the first lens group has a negative optical power and includes at least a first lens with negative optical power, the second lens group has a positive optical power and includes at least a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, and an eighth lens with positive optical power, and the third lens group has a negative optical power and includes a ninth lens with negative optical power. By reasonably setting the optical power of each lens group, the number of lenses included in each lens group, and the optical power of each lens, it is beneficial to achieve a scanning lens with small distortion.

[0041] 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

[0042] 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.

[0043] Figure 1 This is a schematic diagram of the structure of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 1 of this utility model;

[0044] Figure 2 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 1 of this utility model;

[0045] Figure 3 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 200mm, provided in Embodiment 1 of this utility model;

[0046] Figure 4 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 800mm, provided in Embodiment 1 of this utility model;

[0047] Figure 5 This is a schematic diagram of the field curvature distortion curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 1 of this utility model;

[0048] Figure 6 This is a schematic diagram of the relative illumination curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 1 of this utility model;

[0049] Figure 7 This is a schematic diagram of the structure of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 2 of this utility model;

[0050] Figure 8 This is a schematic diagram of the MTF curve of an industrial line scan lens at a 400mm object distance, provided in Embodiment 2 of this utility model;

[0051] Figure 9 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 200mm, provided in Embodiment 2 of this utility model;

[0052] Figure 10 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 800mm, provided in Embodiment 2 of this utility model;

[0053] Figure 11 This is a schematic diagram of the field curvature distortion curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 2 of this utility model.

[0054] Figure 12 This is a schematic diagram of the relative illumination curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 2 of this utility model;

[0055] Figure 13 This is a schematic diagram of the structure of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 3 of this utility model;

[0056] Figure 14 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 3 of this utility model;

[0057] Figure 15This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 200mm, provided in Embodiment 3 of this utility model;

[0058] Figure 16 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 800mm, provided in Embodiment 3 of this utility model;

[0059] Figure 17 This is a schematic diagram of the field curvature distortion curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 3 of this utility model;

[0060] Figure 18 This is a schematic diagram of the relative illumination curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 3 of this utility model. DETAILED DESCRIPTION

[0061] 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.

[0062] Example 1

[0063] Figure 1 This is a schematic diagram of the structure of an industrial line scan lens at an object distance of 400mm, as provided in Embodiment 1 of this utility model. Figure 1 As shown, the industrial line scan lens provided in this embodiment includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged sequentially from the object plane to the image plane along the optical axis; the positions of the first lens group S1 and the third lens group S3 are fixed, while the position of the second lens group S2 can float along the optical axis; the optical power of the first lens group S1 is negative, the optical power of the second lens group S2 is positive, and the optical power of the third lens group S3 is negative; the industrial line scan lens also includes a first lens 101 with negative optical power and a second lens 101 with negative optical power arranged sequentially from the object plane to the image plane along the optical axis. The lens group S1 includes at least the first lens 101, the second lens group S2 includes at least the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the eighth lens 108, and the ninth lens 109; the third lens group S3 includes the ninth lens 109. (The first lens group S1 includes at least the first lens 101, the second lens group S2 includes at least the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, and the eighth lens 108.)

[0064] Specifically, the industrial line scan lens provided in this embodiment includes a first lens group S1, a third lens group S3, and a second lens group S2 located between the first lens group S1 and the third lens group S3 along the optical axis. The first lens group S1 and the third lens group S3 can both be understood as lenses with fixed positions, while the second lens group S2 can be understood as a lens group whose position changes. The second lens group S2 moves between the first lens group S1 and the third lens group S3. The focal length of the industrial line scan lens is adjusted by changing the position of the second lens group S2, ensuring that the industrial line scan lens can focus at different object distances and guarantee clear imaging at various object distances. Furthermore, since the positions of the first lens group S1 and the third lens group S3 remain fixed, the aberration changes caused by the movement of the second lens group S2 at different working distances are mitigated by the fixed positions of the first lens group S1 and the third lens group S3, maintaining symmetry. This ensures that the image quality is balanced at each working distance, guaranteeing imaging quality.

[0065] Furthermore, the optical power of the first lens group S1 is negative, the optical power of the second lens group S2 is positive, and the optical power of the third lens group S3 is negative. Optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of the 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 of the optical power, the weaker the bending ability of light. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. In the industrial line scanning lens provided by this embodiment, the first lens group S1, as the lens that first adjusts the incident light in the scanning lens, has a negative optical power setting that can quickly converge the light and then diverge it to the second lens group S2 with positive optical power to achieve focusing at different object distances. The negative optical power setting of the third lens group S3 ensures that the emitted light can further achieve clear imaging while achieving the required image height.

[0066] Furthermore, the industrial scanning lens provided in this embodiment specifically includes a first lens 101 with negative optical power, a second lens 102 with negative optical power, a third lens 103 with positive optical power, a fourth lens 104 with negative optical power, a fifth lens 105 with positive optical power, a sixth lens 106 with positive optical power, a seventh lens 107 with negative optical power, 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. The first lens 101 and the second lens 102, as the lenses that first adjust the incident light in the scanning lens, have a negative optical power setting that ensures a larger aperture before the light enters the aperture stop, increasing the aperture of the scanning lens and enabling the lens to still produce clear images under dim or dark conditions. The third lens 103, with its positive optical power setting, can promptly correct the large aberrations produced by the first lens 101 and the second lens 102, especially significantly correcting the edge aberrations of the scanning lens, thereby improving the imaging resolution of the optical system. Furthermore, the fourth lens 104 is a negative power lens, the fifth and sixth lenses 105 and 106 are positive power lenses, the seventh lens 107 is a negative power lens, the eighth lens 108 is a positive power lens, and the ninth lens 109 is a negative power lens. Lenses 104 to 109 are arranged in a negative-positive-positive-negative-positive-negative configuration, which, combined with positive power, facilitates aberration correction. Moreover, the arrangement of nine lenses ensures a reasonable number of lenses in the optical system. Too many lenses result in large lens sizes, while too few lenses cause significant aberrations due to individual lenses bearing excessive power. This arrangement ensures both miniaturization of the optical system and low imaging aberrations, resulting in high image quality.

[0067] Furthermore, the first lens group S1 includes at least a first lens 101, the second lens group S2 includes at least a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, and an eighth lens 108, and the third lens group S3 includes a ninth lens 109. In different embodiments, the second lens 102 and the third lens 103 may be disposed within the first lens group S2 or within the second lens group S2. Figure 1 In the illustrated embodiment, the second lens 102 and the third lens 103 are disposed in the second lens group S2. By reasonably setting the number of lenses contained in each lens group, and by matching the optical power of the lenses, the optical power requirements of the lens group are met, thus achieving clear imaging of the scanning lens at different object distances.

[0068] In summary, the industrial line scan lens provided by this embodiment of the invention features a second 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 first and third lens groups remain fixed, which reduces the impact of the second lens group's movement on aberrations and ensures balanced image quality at each working distance. Moreover, the first lens group has a negative optical power, including at least a first lens with negative optical power; the second lens group has a positive optical power, including at least a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, and an eighth lens with positive optical power; and the third lens group has a negative optical power, including a ninth lens with negative optical power. By rationally setting the optical power of each lens group, the number of lenses in each lens group, and the optical power of each lens, it is beneficial to achieve a scanning lens with low distortion and good imaging quality.

[0069] Based on the above embodiments, such as Figure 1 As shown, the first lens group S1 includes a first lens 101, and the second lens group S2 includes a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, and an eighth lens 108; or, the first lens group includes a first lens, a second lens, and a third lens; and the second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. This arrangement will be described in subsequent embodiments. Reasonably setting the number of lenses in the first lens group S1 and the second lens group S2 facilitates the design of negative optical power in the first lens group S1 and positive optical power in the second lens group S2, thereby ensuring the imaging requirements of the industrial scanning lens.

[0070] Based on the above embodiments, the optical power of the first lens group S1 is Φa, the optical power of the second lens group S2 is Φb, and the optical power of the third lens group S3 is Φc; wherein...

[0071] 0.9128≤|(Φa-Φb) / (Φc-Φb)|≤1.0145; 0.8058≤|Φa / Φc|≤1.0369. Using the above limiting method, the ratio between the optical power of the first lens group S1 and the third lens group S3 is near 1. Simultaneously, the ratios between the optical power difference between the first lens group S1 and the second lens group S2, and between the optical power difference between the third lens group S3 and the second lens group S2, are also near 1. This indicates a balanced distribution of optical power among the lens groups, resulting in a higher relative illumination and lower tolerance sensitivity in the optical system, which is beneficial for assembly.

[0072] Based on the above embodiments, the second lens S2 and the third lens S3 are cemented together, or the second lens S2 and the third lens S3 are independently disposed; the industrial line scan lens also includes an aperture stop STO, which is disposed in the optical path between the fifth lens 105 and the sixth lens 106; the fourth lens 104 and the fifth lens 105 are cemented together, and the sixth lens 106 and the seventh lens 107 are cemented together.

[0073] Based on the above embodiments, the second lens 102 and the third lens 103 can be cemented together or not cemented together, i.e., independently. When the second lens 102 and the third lens 103 are cemented together to form a cemented lens, the cemented lens can be used to minimize or eliminate chromatic aberration. Using a cemented lens in industrial line scan lenses can improve image quality and reduce light energy reflection loss, thereby improving the clarity of the lens image. Furthermore, cementing the lenses eliminates the air gap between the two lenses, making the overall optical system compact and meeting the requirements for system miniaturization. Moreover, cementing the lenses reduces tolerance sensitivity issues such as tilting / eccentricity that occur during the assembly of the lens units. For example, the second lens 102 and the third lens 103 can be supported by a gasket or cemented together with adhesive. When the second lens 102 and the third lens 103 are independently configured, the configuration of the second lens 102 and the third lens 103 has a high degree of freedom and the configuration method is relatively simple.

[0074] It should be noted that, Figure 1 In the embodiment shown, the second lens 102 and the third lens 103 are set independently. In subsequent embodiments, the case where the second lens and the third lens are cemented together will be described.

[0075] Further reference Figure 1 As shown, the industrial line scan lens may also include an aperture stop STO, which is positioned in the optical path between the fifth lens 105 and the sixth lens 106. The aperture stop STO can adjust the propagation direction of the light beam, which helps improve image quality. Furthermore, in this scanning lens, the aperture stop STO is positioned in the optical path between the fifth lens 105 and the sixth lens 106, meaning the aperture stop STO is integrated into the optical system. This allows for a reduction in the aperture value, achieving a large aperture.

[0076] Further reference Figure 1 As shown, the industrial line scan lens 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 the imaging effect.

[0077] Furthermore, the industrial line scan lens provided in this embodiment may also include a protective glass and an image acquisition element. The protective glass can be disposed on the image-side of the filter, and the image acquisition element can be disposed on the image-side of the protective glass. The optical system is protected by the protective glass, and the image acquisition element acquires images, thus enabling the optical system to perform its normal imaging function.

[0078] Furthermore, the fourth lens 104 and the fifth lens 105 are cemented together, and the sixth lens 106 and the seventh lens 107 are cemented together. That is, cemented lenses are formed in the optical paths on both sides of the aperture STO, which further eliminates chromatic aberration, improves image quality, reduces light energy reflection loss, and thus improves the clarity of the lens image.

[0079] Based on the above embodiments, the Abbe number of the fourth lens 104 is vd4, the Abbe number of the fifth lens 105 is nd5, the refractive index of the sixth lens 106 is nd6, the refractive index of the seventh lens 107 is nd7, and the refractive index of the eighth lens 108 is nd8; wherein, 73.9234≤vd4+vd5≤123.5863; 0.0909≤(nd7-nd6) / nd8≤0.1420.

[0080] Specifically, the refractive index is a coefficient used to represent the ability of a transparent medium to refract light. The higher the refractive index, the stronger the refraction of incident light; conversely, the weaker the refraction of incident light. The Abbe number is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number. Setting the Abbe numbers of the fourth lens 104 and the fifth lens 105 to satisfy 73.9234≤vd4+vd5≤123.5863, and the refractive indices of the sixth lens 106, the seventh lens 107, and the eighth lens 108 to satisfy 0.0909≤(nd7-nd6) / nd8≤0.1420, can effectively control the spherical aberration generated after the light passes through the first lens group and before and after the aperture stop, and minimize chromatic aberration when the light enters the aperture stop with a large change in the angle of refraction, thus balancing some off-axis chromatic aberration.

[0081] Based on the above embodiment, the optical power of the second lens 102 is Φ2, the optical power of the third lens 103 is Φ3, the optical power of the cemented lens formed by the fourth lens 104 and the fifth lens 105 is Φ45, the optical power of the cemented lens formed by the sixth lens and the seventh lens is Φ67, and the optical power of the eighth lens is Φ8; wherein, -0.9110≤Φ2 / Φ3≤-0.6939; -16.8636≤Φ8 / (Φ45+Φ67)≤-5.5830. These conditions ensure that the ratio of the second lens 102 to the third lens 103 is close to 1, resulting in minimal refraction of light passing through them and low tolerance sensitivity while correcting aberrations. Furthermore, after light passes through the two sets of symmetrical cemented lens groups formed by the fourth lens 104 and the seventh lens 107, higher-order aberrations can be effectively reduced. Furthermore, the above-mentioned constraints satisfy that the optical power of the eighth lens 108 is much greater than the sum of the optical power of the two cemented lenses, thus enabling the light to quickly meet the image height and the required target surface requirements, thereby realizing a large target surface design.

[0082] Based on the above embodiments, the refractive index of the first lens 101 is nd1 and the Abbe number is vd1; the refractive index of the second lens 102 is nd2 and the Abbe number is vd2; the refractive index of the third lens 103 is nd3 and the Abbe number is vd3; wherein, 1.6166≤nd1≤1.7119, 27.4351≤vd1≤52.0986; 1.4490≤nd2≤1.7036, 35.0075≤vd2≤85.0000; 1.7960≤nd3≤2.0566; 27.0256≤vd3≤47.0051. When the first lens 101, as a negative power lens, satisfies the range of 1.6166≤nd1≤1.7119 and 27.4351≤vd1≤52.0986, it can quickly converge light from a large field of view into the optical system and correct some aberrations in the large field of view area. The second lens 102, as a negative power lens, and the third lens 103, as a positive power lens, are paired with each other in terms of positive and negative power. When they satisfy 35.0075≤vd2≤85.0000 and 1.7960≤nd3≤2.0566, the high refractive index and high Abbe number can not only continue to converge light to make the lens diameter smaller, but also further reduce off-axis chromatic aberration, allowing light to enter the moving group more smoothly.

[0083] Based on the above embodiments, the focal length of the industrial line scan lens at an object distance of 400 mm is f, the full field angle of the industrial line scan lens is w, the total optical length of the industrial line scan lens is TTL, and the back focal length of the industrial line scan lens is BFL; wherein, 5.7930 ≤ (f / w) * 10 ≤ 6.0115; 2.7152 ≤ TTL / f ≤ 2.9262; 0.1204 < BFL / TTL < 0.1869. When the above conditions are met under the condition of a large field angle and a short focal length, by restricting the relationship between the lens focal length and the total lens length, it is beneficial to reduce the volume of the overall optical system, make the finished lens smaller, and be able to match more usage environments. Moreover, through the reasonable selection of the above back focal length and total optical length, it is ensured that the imaging sensor and the flat filter have sufficient installation space, and it can be ensured that the lens will not interfere with the base and the housing during installation, ensuring that the assembly process of the line scan lens is simple.

[0084] Based on the above embodiments, the first lens 101 includes a first object side surface close to the object surface side and a first image side surface close to the image surface side. The first object side surface is a convex surface, and the first image side surface is a concave surface; the second lens 102 includes a second object side surface close to the object surface side and a second image side surface close to the image surface side. The second object side surface is a concave surface, and the second image side surface is a concave surface or a convex surface; the third lens 103 includes a third object side surface close to the object surface side and a third image side surface close to the image surface side. The third object side surface is a convex surface or a concave surface, and the third image side surface is a convex surface; the fourth lens 104 includes a fourth object side surface close to the object surface side and a fourth image side surface close to the image surface side. The fourth object side surface is a convex surface, and the fourth image side surface is a concave surface; the fifth lens 105 includes a fifth object side surface close to the object surface side and a fifth image side surface close to the image surface side. The fifth object side surface is a convex surface, and the fifth image side surface is a convex surface; the sixth lens 106 includes a sixth object side surface close to the object surface side and a sixth image side surface close to the image surface side. The sixth object side surface is a concave surface or a convex surface, and the sixth image side surface is a convex surface; the seventh lens 107 includes a seventh object side surface close to the object surface side and a seventh image side surface close to the image surface side. The seventh object side surface is a concave surface, and the seventh image side surface is a concave surface; the eighth lens 108 includes an eighth object side surface close to the object surface side and an eighth image side surface close to the image surface side. The eighth object side surface is a concave surface, and the eighth image side surface is a convex surface; the ninth lens 109 includes a ninth object side surface close to the object surface side and a ninth image side surface close to the image surface side. The ninth object side surface is a concave surface, and the ninth image side surface is a convex surface.

[0085] 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 can be understood as the surface of the lens closest to the image plane. The object-side surface of the first lens 101 is convex, and the image-side surface is concave. This can be understood as the object-side surface of the first lens 101 bulging towards the object plane near the optical axis, and the image-side surface concave towards the image plane near the optical axis; that is, the first lens 101 is a lens with a convex-concave structure. Furthermore, the first lens 101 can be a meniscus negative lens. The surface shape of the first lens 101, combined with its optical power parameters, can converge light rays from a large field of view into the system as much as possible, which is beneficial for improving the field of view of the optical system.

[0086] The object-side surface of the second lens 102 is concave, while the image-side surface is either concave or convex. This can be understood as the object-side surface of the second lens 102 being concave towards the object plane near the optical axis, and the image-side surface being concave or convex towards the image plane near the optical axis. In other words, the second lens 102 is a lens with a biconcave or concave-convex structure. Figure 1 The following explanation uses a lens with a biconcave structure as an example. The second lens 102 is designed as a biconvex or concave-convex negative lens, which can effectively control the direction of light, reduce field curvature and spherical aberration of the optical system, and improve the image quality of the optical system.

[0087] The object-side surface of the third lens 103 is either convex or concave, and the image-side surface is convex. This can be understood as the object-side surface of the third lens 103 bulging or concave towards the object plane near the optical axis, and the image-side surface bulging towards the image plane near the optical axis. Therefore, the third lens 103 is a biconvex or concave-convex lens. The object-side surface of the fourth lens 104 is convex, and the image-side surface is concave. This can be understood as the object-side surface of the fourth lens 104 bulging towards the object plane near the optical axis, and the image-side surface concave towards the image plane near the optical axis. Therefore, the fourth lens 104 is a convex-concave lens. The surface design of the third lens 103 and the fourth lens 104, their optical power, and their placement within the optical system effectively reduce light rays and decrease the overall length of the optical system, which is beneficial for miniaturized lens design.

[0088] The fifth lens 105 has a convex object-side surface and a convex image-side surface. This can be understood as the object-side surface of the fifth lens 105 bulging towards the object plane near the optical axis, and the image-side surface bulging towards the image plane near the optical axis; therefore, the fifth lens 105 is a biconvex lens. The sixth lens 106 has a concave or convex object-side surface and a convex image-side surface. This can be understood as the object-side surface of the sixth lens 106 being concave or convex towards the object plane near the optical axis, and the image-side surface bulging towards the image plane near the optical axis; therefore, the sixth lens 106 is a concave-convex or biconvex lens. The surface profiles of the fifth and sixth lenses 105, combined with their optical power parameters, can further correct off-axis aberrations and improve the imaging quality of the edge fields of view.

[0089] The seventh lens 107 has a concave object-side surface and a concave image-side surface. This can be understood as the object-side surface of the seventh lens 107 being concave towards the object plane near the optical axis, and the image-side surface being concave towards the image plane near the optical axis; therefore, the seventh lens 107 is a double-concave lens. The eighth lens 108 has a concave object-side surface and a convex image-side surface. This can be understood as the object-side surface of the eighth lens 108 being concave towards the object plane near the optical axis, and the image-side surface being convex towards the image plane near the optical axis; therefore, the eighth lens 108 is a concave-convex lens. The ninth lens 109 has a concave object-side surface and a convex image-side surface. This can be understood as the object-side surface of the ninth lens 109 being concave towards the object plane near the optical axis, and the image-side surface being convex towards the image plane near the optical axis; therefore, the ninth lens 109 is a concave-convex lens. When the shapes of the seventh lens 107, eighth lens 108, and ninth lens 109 are distributed in this way, it is beneficial for correcting the field curvature of the system.

[0090] Furthermore, the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the eighth lens 108, and the ninth lens 109 all include glass spherical lenses.

[0091] Specifically, spherical lenses are characterized by a constant curvature from the center to the periphery, ensuring a simple lens setup. Furthermore, due to the low coefficient of thermal expansion and good stability of glass lenses, the first lens 101, second lens 102, third lens 103, fourth lens 104, fifth lens 105, sixth lens 106, seventh lens 107, eighth lens 108, and ninth lens 109 are all glass spherical lenses. This balances high and low temperatures, helping to maintain focal length stability when the ambient temperature of the industrial line scan lens varies significantly, for example, ensuring stable optical performance between -40℃ and 85℃.

[0092] As a feasible implementation method, the parameters of each lens in the industrial line scan lens will be explained next.

[0093] Table 1. Optical design values ​​for a fixed-focus lens in Example 1.

[0094] Scope of protection Example 1 Lower limit upper limit nd1 1.6166 1.6166 1.7119 vd1 52.0986 27.4351 52.0986 nd2 1.4490 1.4904 1.7036 vd2 57.1675 35.0075 85.000 nd3 1.7960 1.7960 2.0566 vd3 47.0051 27.0256 47.0051 vd4+vd5 123.5863 73.9234 123.5863 (nd7-nd6) / nd8 0.0909 0.0909 0.1420 (Φa-Φb) / (Φc-Φb) 1.0145 0.9128 1.0145 Φa / Φc 1.0369 0.8058 1.0369 Φ2 / Φ3 -0.6939 -0.9110 -0.6939 Φ8 / (Φ45+Φ67) -5.5830 -16.8636 -5.5830 (f / w)*10 5.9477 5.7930 6.0115 TTL / f 2.7152 2.7152 2.9262 BFL / TTL 0.1869 0.1204 0.1869

[0095] Table 2 Design values ​​of optical physical parameters for industrial line scan lenses

[0096]

[0097] The surface numbers in Table 2 are assigned according to the surface sequence of each lens. "STO" represents the aperture stop of the lens. The radius of curvature represents the curvature of the corresponding lens surface. A positive value means that the surface bends towards the image plane, and a negative value means that the surface bends towards the object plane. "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 represents that the current position is air and the refractive index is 1.

[0098] Table 3. Distances between the centers of the second lens group and the first and third lens groups at different object distances.

[0099] Near object distance (mm) Optimal object distance (mm) Distance to distant object (mm) surface 200 400 800 S2 13.5175 9.1985 15.2140 S15 13.6997 18.0187 12.0032

[0100] Wherein, S2 represents the distance between the front end of the second lens group and the first lens group, and S15 represents the distance between the rear end of the second lens group and the third lens group.

[0101] Figure 2 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 1 of this utility model. Figure 3 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 200mm, provided in Embodiment 1 of this utility model. Figure 4 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 800mm, provided in Embodiment 1 of this utility model. Figure 2 , Figure 3 and Figure 4 As shown, the horizontal axis represents spatial frequency, which refers to the number of black and white line pairs per millimeter. The vertical axis represents the modulation modulus (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging; therefore, 0 ≤ M' / M ≤ 1. The MTF curve represents the resolving power of the optical system for objects at different frequencies in different fields of view, meridional, and sagittal directions. It reflects the degree of image quality after the object passes through the optical system; the higher the MTF, the higher the image quality of the lens. From... Figure 2 , Figure 3 and Figure 4 It can be seen that the MTF of the optical system in all meridional and sagittal directions of the field of view is greater than 0.3 at a spatial frequency of 70 lp / mm, which has a very high imaging effect for line scan lenses.

[0102] Figure 5 This is a schematic diagram of the field curvature distortion curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 1 of this utility model. In the coordinate system on the right side of the figure, the horizontal axis represents the magnitude of distortion, in percentage; the vertical axis represents the normalized image height, which has no unit. Figure 5 As can be seen, the lens provided in this embodiment has achieved excellent distortion correction, ensuring good image fidelity and minimizing distortion. In the coordinate system on the left side of the figure, the horizontal axis represents the field curvature in mm; the vertical axis represents the normalized image height (unitless). Figure 5 It can be seen that the resolution difference between the center of the field curvature and the vicinity of the edge field of view provided in this embodiment is relatively small.

[0103] Figure 6 This is a schematic diagram of the relative illuminance curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 1 of this utility model. The vertical direction represents the relative illuminance, with 0 indicating zero illuminance and no light passing through the field of view; the vertex represents the maximum illuminance, where there is no vignetting and all light passes through; the horizontal direction represents the range from zero field of view to the maximum field of view. The greater the relative illuminance, the more light passes through, and the less likely vignetting is to occur. Figure 6 As can be seen, the relative illumination is 57%, which is suitable for most situations.

[0104] In summary, the industrial line scan lens provided by this utility model embodiment has low distortion in the object distance range of 200-800mm, an illuminance of over 57%, and an MTF70 line pairs / mm>0.3, ensuring that it can achieve a large target area, low distortion, and high image quality.

[0105] Example 2

[0106] Figure 7 This is a schematic diagram of the structure of an industrial line scan lens at an object distance of 400mm, as provided in Embodiment 2 of this utility model. Figure 7As shown, the industrial line scanning lens provided in Embodiment 2 of this utility model includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged sequentially from the object plane to the image plane along the optical axis; the positions of the first lens group S1 and the third lens group S3 are fixed, while the position of the second lens group S2 can float along the optical axis; the optical power of the first lens group S1 is negative, the optical power of the second lens group S2 is positive, and the optical power of the third lens group S3 is negative; the industrial line scanning lens also includes a first lens 101 with negative optical power and a second lens 101 with negative optical power arranged sequentially from the object plane to the image plane along the optical axis. The lens group S1 includes at least the first lens 101, the second lens group S2 includes at least the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the eighth lens 108, and the ninth lens 109; the third lens group S3 includes the ninth lens 109. (The first lens group S1 includes at least the first lens 101, the second lens group S2 includes at least the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, and the eighth lens 108.)

[0107] The difference between Embodiment 2 and Embodiment 1 is that the first lens group S1 includes a first lens 101, a second lens 102, and a third lens 103, while the second lens group S2 includes a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, and an eighth lens 108. Furthermore, in Embodiment 2, the second lens 102 and the third lens 103 are cemented together, and the concave-convex shape of some lenses differs from that in Embodiment 1.

[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 of the industrial line scan lens are explained below.

[0110] Table 4. Optical design values ​​for a fixed-focus lens in Example 2.

[0111] Scope of protection Example 2 Lower limit upper limit nd1 1.6925 1.6166 1.7119 vd1 27.4351 27.4351 52.0986 nd2 1.4904 1.4904 1.7036 vd2 85.000 35.0075 85.000 nd3 1.9947 1.7960 2.0566 vd3 27.4034 27.0256 47.0051 vd4+vd5 79.3117 73.9234 123.5863 (nd7-nd6) / nd8 0.1418 0.0909 0.1420 (Φa-Φb) / (Φc-Φb) 0.9381 0.9128 1.0145 Φa / Φc 0.8572 0.8058 1.0369 Φ2 / Φ3 -0.8034 -0.9110 -0.6939 Φ8 / (Φ45+Φ67) -16.8636 -16.8636 -5.5830 (f / w)*10 6.0115 5.7930 6.0115 TTL / f 2.8635 2.7152 2.9262 BFL / TTL 0.1495 0.1204 0.1869

[0112] Table 5 Design values ​​of optical physical parameters for industrial line scan lenses

[0113]

[0114] The surface numbers in Table 5 are assigned according to the surface sequence of each lens. "STO" represents the aperture stop of the lens. The radius of curvature represents the curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "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.

[0115] Table 6. Distances between the centers of the second lens group and the first and third lens groups at different object distances.

[0116] Near object distance (mm) Optimal object distance (mm) Distance to distant object (mm) surface 200 400 800 S5 7.8023 4.0777 9.3969 S14 18.8439 22.5685 17.2493

[0117] Wherein, S5 represents the distance between the front end of the second lens group and the first lens group, and S14 represents the distance between the rear end of the second lens group and the third lens group.

[0118] Figure 8 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 2 of this utility model. Figure 9 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 200mm, provided in Embodiment 2 of this utility model. Figure 10 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 800mm, provided in Embodiment 2 of this utility model. Figure 8 , Figure 9 and Figure 10 As shown, the horizontal axis represents spatial frequency, which refers to the number of black and white line pairs per millimeter. The vertical axis represents the modulation modulus (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging; therefore, 0 ≤ M' / M ≤ 1. The MTF curve represents the resolving power of the optical system for objects at different frequencies in different fields of view, meridional, and sagittal directions. It reflects the degree of image quality after the object passes through the optical system; the higher the MTF, the higher the image quality of the lens. From... Figure 8 , Figure 9 and Figure 10 It can be seen that the MTF of the optical system in all meridional and sagittal directions of the field of view is greater than 0.3 at a spatial frequency of 70 lp / mm, which has a very high imaging effect for line scan lenses.

[0119] Figure 11 This is a schematic diagram of the field curvature distortion curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 2 of this utility model. In the coordinate system on the right side of the figure, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit. Figure 11As can be seen, the lens provided in this embodiment has achieved excellent distortion correction, ensuring good image fidelity and minimizing distortion. In the coordinate system on the left side of the figure, the horizontal axis represents the field curvature in mm; the vertical axis represents the normalized image height (unitless). Figure 11 It can be seen that the resolution difference between the center of the field curvature and the vicinity of the edge field of view provided in this embodiment is relatively small.

[0120] Figure 12 This is a schematic diagram of the relative illuminance curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 2 of this utility model. The vertical direction represents the relative illuminance, with 0 indicating zero illuminance and no light passing through the field of view; the vertex represents the maximum illuminance, where there is no vignetting and all light passes through; the horizontal direction represents the range from zero field of view to the maximum field of view. The greater the relative illuminance, the more light passes through, and the less likely vignetting is to occur. Figure 12 As can be seen, the relative illumination is 59%, which is suitable for most situations.

[0121] In summary, the industrial line scan lens provided by this utility model embodiment has low distortion in the object distance range of 200-800mm, an illuminance of over 59%, and an MTF70 line pairs / mm>0.3, ensuring that it can achieve a large target area, low distortion, and high image quality.

[0122] Example 3

[0123] Figure 13 This is a schematic diagram of the structure of an industrial line scan lens at an object distance of 400mm, as provided in Embodiment 3 of this utility model. Figure 13 As shown, the industrial line scanning lens provided in Embodiment 3 of this utility model includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged sequentially from the object plane to the image plane along the optical axis; the positions of the first lens group S1 and the third lens group S3 are fixed, while the position of the second lens group S2 can float along the optical axis; the optical power of the first lens group S1 is negative, the optical power of the second lens group S2 is positive, and the optical power of the third lens group S3 is negative; the industrial line scanning lens also includes a first lens 101 with negative optical power and a second lens 101 with negative optical power arranged sequentially from the object plane to the image plane along the optical axis. The lens group S1 includes at least the first lens 101, the second lens group S2 includes at least the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the eighth lens 108, and the ninth lens 109; the third lens group S3 includes the ninth lens 109. (The first lens group S1 includes at least the first lens 101, the second lens group S2 includes at least the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, and the eighth lens 108.)

[0124] The difference between Embodiment 3 and Embodiment 1 is that the first lens group S1 includes a first lens 101, a second lens 102, and a third lens 103, and the second lens group S2 includes a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, and an eighth lens 108. Furthermore, in Embodiment 3, the second lens 102 and the third lens 103 are cemented together, and the concave and convex shapes of some lenses differ from those in Embodiment 1.

[0125] Other parameters are the same as in Example 1, and will not be repeated here.

[0126] As another feasible implementation method, the specific parameters of the industrial line scan lens are explained below.

[0127] Table 7. Optical design values ​​for a fixed-focus lens in Example 3.

[0128] Scope of protection Example 3 Lower limit upper limit nd1 1.7119 1.6166 1.7119 vd1 47.6847 27.4351 52.0986 nd2 1.7036 1.4904 1.7036 vd2 35.0075 35.0075 85.000 nd3 2.0566 1.7960 2.0566 vd3 27.0256 27.0256 47.0051 vd4+vd5 73.9234 73.9234 123.5863 (nd7-nd6) / nd8 0.1420 0.0909 0.1420 (Φa-Φb) / (Φc-Φb) 0.9128 0.9128 1.0145 Φa / Φc 0.8058 0.8058 1.0369 Φ2 / Φ3 -0.9110 -0.9110 -0.6939 Φ8 / (Φ45+Φ67) -8.9395 -16.8636 -5.5830 (f / w)*10 5.7930 5.7930 6.0115 TTL / f 2.9262 2.7152 2.9262 BFL / TTL 0.1204 0.1204 0.1869

[0129] Table 8 Optical Design Values ​​of Each Lens in an Industrial Line Scan Lens

[0130]

[0131] The surface numbers in Table 8 are assigned according to the surface sequence of each lens. "STO" represents the aperture stop of the lens. The radius of curvature represents the curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "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.

[0132] Table 9. Distances between the centers of the second lens group and the first and third lens groups at different object distances.

[0133] Near object distance (mm) Optimal object distance (mm) Distance to distant object (mm) surface 200 400 800 S5 5.0903 1.9202 6.4834 S14 17.0927 20.2628 15.6996

[0134] Wherein, S5 represents the distance between the front end of the second lens group and the first lens group, and S14 represents the distance between the rear end of the second lens group and the third lens group.

[0135] Figure 14 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 3 of this utility model. Figure 15 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 200mm, provided in Embodiment 3 of this utility model. Figure 16 This is a schematic diagram of the MTF curve of an industrial line scan lens at an object distance of 800mm, provided in Embodiment 3 of this utility model. Figure 14 , Figure 15 and Figure 16 As shown, the horizontal axis represents spatial frequency, which refers to the number of black and white line pairs per millimeter. The vertical axis represents the modulation modulus (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging; therefore, 0 ≤ M' / M ≤ 1. The MTF curve represents the resolving power of the optical system for objects at different frequencies in different fields of view, meridional, and sagittal directions. It reflects the degree of image quality after the object passes through the optical system; the higher the MTF, the higher the image quality of the lens. From... Figure 14 , Figure 15 and Figure 16 It can be seen that the MTF of the optical system in all meridional and sagittal directions of the field of view is greater than 0.3 at a spatial frequency of 70 lp / mm, which has a very high imaging effect for line scan lenses.

[0136] Figure 17 This is a schematic diagram of the field curvature distortion curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 3 of this utility model. In the coordinate system on the right side of the figure, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit. Figure 17 As can be seen, the lens provided in this embodiment has achieved excellent distortion correction, ensuring good image fidelity and minimizing distortion. In the coordinate system on the left side of the figure, the horizontal axis represents the field curvature in mm; the vertical axis represents the normalized image height (unitless). Figure 17 It can be seen that the resolution difference between the center of the field curvature and the vicinity of the edge field of view provided in this embodiment is relatively small.

[0137] Figure 18 This is a schematic diagram of the relative illuminance curve of an industrial line scan lens at an object distance of 400mm, provided in Embodiment 3 of this utility model. The vertical direction represents the relative illuminance, with 0 indicating zero illuminance and no light passing through the field of view; the vertex represents the maximum illuminance, where there is no vignetting and all light passes through; the horizontal direction represents the range from zero field of view to the maximum field of view. The greater the relative illuminance, the more light passes through, and the less likely vignetting is to occur. Figure 18 As can be seen, the relative illumination is 59%, which is suitable for most situations.

[0138] In summary, the industrial line scan lens provided by this utility model embodiment has low distortion in the object distance range of 200-800mm, an illuminance of over 59%, and an MTF70 line pairs / mm>0.3, ensuring that it can achieve a large target area, low distortion, and high image quality.

[0139] 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 line scan lens, characterized in that, It includes a first lens group, a second lens group, and a third lens group arranged sequentially along the optical axis from the object plane to the image plane; the positions of the first lens group and the third lens group are fixed, while the position of the second lens group can float along the optical axis. The optical power of the first lens group is negative, the optical power of the second lens group is positive, and the optical power of the third lens group is negative. The industrial line scan lens further includes a first lens with negative 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 positive optical power, a seventh lens with negative optical power, 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 first lens group includes at least the first lens; the second lens group includes at least the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens; and the third lens group includes the ninth lens.

2. The industrial line scan lens according to claim 1, characterized in that, The first lens group includes a first lens, and the second lens group includes a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens; Alternatively, the first lens group may include a first lens, a second lens, and a third lens; the second lens group may include a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

3. The industrial line scan lens according to claim 1, characterized in that, The optical power of the first lens group is Φa, the optical power of the second lens group is Φb, and the optical power of the third lens group is Φc; Among them, 0.9128≤|(Φa-Φb) / (Φc-Φb)|≤1.0145; 0.8058≤|Φa / Φc|≤1.0369.

4. The industrial line scan lens according to claim 1, characterized in that, The second lens and the third lens are cemented together, or the second lens and the third lens are independently disposed; The industrial line scan lens also includes an aperture stop, which is disposed in the optical path between the fifth lens and the sixth lens; The fourth lens and the fifth lens are cemented together, and the sixth lens and the seventh lens are cemented together.

5. The industrial line scan lens according to claim 4, characterized in that, The second lens has an optical power of Φ2, the third lens has an optical power of Φ3, the fourth and fifth lenses form a cemented lens with an optical power of Φ45, the sixth and seventh lenses form a cemented lens with an optical power of Φ67, and the eighth lens has an optical power of Φ8. Where -0.9110≤Φ2 / Φ3≤-0.6939; -16.8636≤Φ8 / (Φ45+Φ67)≤-5.5830.

6. The industrial line scan lens according to claim 1, characterized in that, The first lens has a refractive index of nd1 and an Abbe number of vd1; the second lens has a refractive index of nd2 and an Abbe number of vd2; and the third lens has a refractive index of nd3 and an Abbe number of vd3. Among them, 1.6166≤nd1≤1.7119, 27.4351≤vd1≤52.0986; 1.4490≤nd2≤1.7036、35.0075≤vd2≤85.0000; 1.7960≤nd3≤2.0566;27.0256≤vd3≤47.0051; 7. The industrial line scan lens according to claim 4, characterized in that, The Abbe number of the fourth lens is vd4, the Abbe number of the fifth lens is nd5, the refractive index of the sixth lens is nd6, the refractive index of the seventh lens is nd7, and the refractive index of the eighth lens is nd8. Among them, 73.9234≤vd4+vd5≤123.5863; 0.0909≤(nd7-nd6) / nd8≤0.1420.

8. The industrial line scan lens according to claim 1, characterized in that, The focal length of the industrial line scan lens at an object distance of 400mm is f, the full field of view of the industrial line scan lens is w, the total optical length of the industrial line scan lens is TTL, and the back focal length of the industrial line scan lens is BFL. Among them, 5.7930≤(f / w)*10≤6.0115; 2.7152≤TTL / f≤2.9262; 0.1204 <BFL / TTL<0.1869。 9. The industrial line scan lens according to claim 1, characterized in that, The first lens includes a first object-side surface near the object plane and a first image-side surface near the image plane. The first object-side surface is convex, and the first image-side surface is concave. The second lens includes a second object-side surface near the object plane and a second image-side surface near the image plane. The second object-side surface is concave, and the second image-side surface is either concave or convex. 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 either convex or concave, and the third image-side surface is convex. 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 concave. 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 either concave or convex, and the sixth image-side surface is convex. 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 concave, 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 concave, and the eighth image-side surface is convex. 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 concave, and the ninth image-side surface is convex.

10. The industrial line scan lens according to claim 1, characterized in that, The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens all include glass spherical lenses.

Images