Industrial line scanning lens

Abstract

The utility model discloses an industrial line scanning lens. The industrial line scanning lens comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with positive focal power, a vignetting diaphragm, a diaphragm, a fourth lens with negative focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power which are sequentially arranged along an optical axis from an object side to an image side, the first lens and the second lens form a doublet lens, and the fourth lens and the fifth lens form a doublet lens; wherein the first lens, the second lens, the third lens, the vignetting diaphragm, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens integrally move for focusing. The industrial line scanning lens can meet the focal length requirement in a large working distance range, has a large imaging target surface, high relative illumination and small distortion, and meets the requirement of high imaging quality.

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 Technology

[0002] With the advancement of technology, industrial automation production is constantly developing, and product inspection is one of the key steps in the industrial automation production process. Currently, industrial cameras are usually used in conjunction with industrial line scan lenses. Linear sensors are used to capture images of products, enabling the detection of appearance defects, dimensional accuracy, label quality, and other aspects based on these images. Therefore, the imaging quality of the industrial line scan lens is one of the key factors affecting the product inspection results.

[0003] To ensure high production efficiency and yield, the demands on the performance of industrial line scanning lenses required for product inspection are constantly increasing. Improving the performance of industrial line scanning lenses, such as resolution, applicable working distance, optical distortion, and image plane size, has become an urgent technical problem to be solved. Utility Model Content

[0004] This invention provides an industrial line scan lens that ensures a wide applicable working distance range, low optical distortion, large image size, and high imaging resolution.

[0005] This utility model provides an industrial line scan lens, which includes: a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a vignetting stop, an aperture stop, a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, and a seventh lens with positive optical power, arranged sequentially along the optical axis from the object side to the image side.

[0006] The first lens and the second lens constitute a cemented doublet lens; the fourth lens and the fifth lens constitute a cemented doublet lens;

[0007] The first lens, the second lens, the third lens, the vignetting stop, the aperture stop, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all moved together for focusing; the aperture stop has a variable diameter.

[0008] Optionally, both the object-side surface and the image-side surface of the first lens are concave.

[0009] Both the object-side and image-side surfaces of the second lens are convex.

[0010] The object-side surface of the third lens is convex, and the image-side surface is concave.

[0011] Both the object-side and image-side surfaces of the fourth lens are concave.

[0012] Both the object side and the image side of the fifth lens are convex surfaces;

[0013] The object side of the sixth lens is a concave surface and the image side is a convex surface;

[0014] The object side of the seventh lens is a concave surface and the image side is a convex surface.

[0015] Optionally, the focal length f1 of the first lens, the focal length f2 of the second lens, and the focal length f3 of the third lens satisfy:

[0016] 0.8 < f1 / f + f2 / f + f3 / f < 1.1; where f is the overall focal length of the industrial line scan lens.

[0017] Optionally, the focal length f3 of the third lens satisfies:

[0018] 0.9 < f3 / f < 1.3; where f is the overall focal length of the industrial line scan lens.

[0019] Optionally, the Abbe number Vd1 of the first lens, the Abbe number Vd2 of the second lens, and the Abbe number Vd3 of the third lens satisfy:

[0020] 80 < Vd3 + Vd2 - Vd1 < 100.

[0021] Optionally, the focal length f4 of the fourth lens, the refractive index Nd of the fourth lens, the focal length f5 of the fifth lens, and the refractive index Nd5 of the fifth lens satisfy:

[0022] 0 < (ND5 - ND4) * (f5 / f - f4 / f) < 0.06; where f is the overall focal length of the industrial line scan lens.

[0023] Optionally, the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.1 < |f6 / f + f7 / f| < 0.14; where f is the overall focal length of the industrial line scan lens.

[0024] Optionally, the refractive index of the sixth lens satisfies: 1.9 < ND6.

[0025] Optionally, the maximum semi-aperture among the semi-apertures of each lens is SDmax;

[0026] Among them, 0.6 < 2 * SDmax / Hmax < 0.67, and Hmax is the maximum image height of the industrial line scan lens.

[0027] Optionally, at the reference object distance of the industrial line scan lens, the distance from the image side of the seventh lens to the image plane of the industrial line scan lens is BFL;

[0028] Where, 0.71 < BFL / f < 0.76, and f is the overall focal length of the industrial line scan lens.

[0029] The technical solution of the present utility model is to form an industrial line scan lens by using seven lenses with optical power, reasonably distributing the optical power of each lens, making the first lens and the second lens form a doublet lens, and making the fourth lens and the fifth lens form a doublet lens, and the aperture of the diaphragm is variable, so as to ensure that the industrial line scan lens has a smaller volume, a lighter mass, more flexible movement, and can achieve fast and clear focusing at different working distances. At the same time, the industrial line scan lens can also have a larger imaging target surface, a higher relative illumination, and a smaller distortion, meeting the requirements of high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic structural diagram of an industrial line scan lens provided by the present utility model;

[0031] Figure 2 is Figure 1 a schematic diagram of the full-frequency MTF of the industrial line scan lens shown in the visible light band;

[0032] Figure 3 is Figure 1 a schematic diagram of the relative illumination curve of the industrial line scan lens shown;

[0033] Figure 4 is Figure 1 a schematic diagram of the field curvature and distortion curve of the industrial line scan lens shown;

[0034] Figure 5 a schematic structural diagram of another industrial line scan lens provided by the present utility model;

[0035] Figure 6 is Figure 5 a schematic diagram of the full-frequency MTF of the industrial line scan lens shown in the visible light band;

[0036] Figure 7 is Figure 5 a schematic diagram of the relative illumination curve of the industrial line scan lens shown;

[0037] Figure 8 is Figure 5 a schematic diagram of the field curvature and distortion curve of the industrial line scan lens shown;

[0038] Figure 9 a schematic structural diagram of yet another industrial line scan lens provided by the present utility model;

[0039] Figure 10 is Figure 9The diagram shows the MTF of an industrial line scan lens across the entire visible light spectrum.

[0040] Figure 11 yes Figure 9 The diagram shows the relative illumination curve of an industrial line scan lens.

[0041] Figure 12 yes Figure 9 The diagram shows the field curvature distortion curve of an industrial line scan lens. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be fully described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Various modifications and variations can be made to this utility model without departing from its spirit or scope, which is obvious to those skilled in the art. Therefore, this utility model is intended to cover modifications and variations of this utility model that fall within the scope of the corresponding claims (the claimed technical solutions) and their equivalents.

[0043] Furthermore, the terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "an," "one," or "the" do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "including" or "comprising" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes. In addition, descriptions of "same" or "equal" in the embodiments of this disclosure do not mean that two objects are completely equal in size or shape; they are allowed to be approximately the same or approximately equal within a certain error range.

[0044] It should be noted that the implementation methods provided in this utility model embodiment can be combined with each other without contradiction.

[0045] Figure 1 This is a structural schematic diagram of an industrial line scan lens provided in an embodiment of this utility model, as shown below. Figure 1As shown, the industrial line scan lens includes: a first lens 10 with negative optical power, a second lens 20 with positive optical power, a third lens 30 with positive optical power, a vignetting stop 80, an aperture stop 90, a fourth lens 40 with negative optical power, a fifth lens 50 with positive optical power, a sixth lens 60 with negative optical power, and a seventh lens 70 with positive optical power, arranged sequentially along the optical axis from the object side to the image side. The first lens 10, second lens 20, third lens 30, vignetting stop 80, aperture stop 90, fourth lens 40, fifth lens 50, sixth lens 60, and seventh lens 70 are moved as a whole for focusing, and the aperture of the aperture stop 90 is variable.

[0046] As can be understood, optical power equals the difference between the convergence of the image-side beam and the convergence of the object-side beam; it characterizes the ability of an optical system to deflect light. The larger the absolute value of optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When optical power is positive, the refraction of light is converging; when 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., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0047] In this embodiment, by setting the first lens 10 to have negative optical power, the second lens 20 to have positive optical power, the third lens 30 to have positive optical power, the fourth lens 40 to have negative optical power, the fifth lens 50 to have positive optical power, the sixth lens 60 to have negative optical power, and the seventh lens 70 to have positive optical power, the optical power of each lens is reasonably allocated, so that the lenses cooperate with each other to meet the requirements of high resolution, low distortion, large imaging target area, and high relative illumination, enabling the industrial line scan lens to have high imaging quality.

[0048] Meanwhile, the aperture 90, located in the optical path between the third lens 30 and the fourth lens 40, can adjust the propagation direction of the light beam, minimizing the front and rear apertures of the industrial line scan lens and improving image quality. Furthermore, the adjustable aperture 90 allows the industrial line scan lens to adjust the amount of light entering the lens at different working distances, achieving clear focusing at various distances. For example, at working distances ranging from 200mm to 900mm, the focal length of the industrial line scan lens can be maintained at approximately 60mm, with an aperture of f / 4.1 at the reference object distance, overall distortion between -0.5% and 0.5%, and an imaging target area of ​​up to 58mm, resulting in high overall imaging performance for the industrial line scan lens.

[0049] The vignetting stop 80 is positioned between the third lens 30 and the stop 90. The vignetting stop 80 can block light rays with large upper or lower pupil aberrations in different fields of view, thereby improving resolution performance, improving CRA, or reducing lens aperture. Furthermore, the vignetting stop 80 helps the optical system of industrial line scan lenses to have higher relative illumination, for example, relative illumination can reach 57%.

[0050] Based on the above embodiments, optionally, the first lens 10 and the second lens 20 constitute a cemented doublet lens.

[0051] The cemented configuration of the first lens 10 and the second lens 20 can be understood as the image-side surface of the first lens 10 being bonded to the object-side surface of the second lens 20. By cementing the first lens 10 and the second lens 20, the air gap between them can be reduced, which helps to reduce the overall optical length of the industrial line scan lens. It also reduces tolerance sensitivity issues such as tilting / eccentricity during lens assembly, simplifies the assembly process in the manufacturing of industrial line scan lenses, and improves equipment efficiency. Simultaneously, the cemented configuration of the first lens 10 and the second lens 20 can reduce light loss caused by inter-lens reflection, improve illumination, and reduce the risk of ghosting. Furthermore, cemented lenses can be used to minimize or eliminate chromatic aberration, thereby improving image quality, reducing light energy reflection loss, and enhancing the sharpness of the lens image. In an optional embodiment, the first lens 10 and the second lens 20 can be supported by a gasket or bonded with adhesive. This invention does not limit the specific bonding method.

[0052] Optionally, the fourth lens 40 and the fifth lens 50 form a cemented doublet lens.

[0053] The cementing of the fourth lens 40 and the fifth lens 50 can be understood as the image-side surface of the fourth lens 40 being bonded to the object-side surface of the fifth lens 50. By cementing the fourth lens 40 and the fifth lens 50, the air gap between them can be reduced, which helps to reduce the overall optical length of the industrial line scan lens. It also reduces tolerance sensitivity issues such as tilting / eccentricity during lens assembly, simplifies the assembly process in the manufacturing of industrial line scan lenses, and improves equipment efficiency. Simultaneously, the cementing of the fourth lens 40 and the fifth lens 50 can reduce light loss caused by inter-lens reflection, improving illumination. Furthermore, cemented lenses can be used to minimize or eliminate chromatic aberration, thereby improving image quality, reducing light energy reflection loss, and enhancing the sharpness of the lens image. In an optional embodiment, the fourth lens 40 and the fifth lens 50 can be supported by a gasket, or they can be bonded with adhesive. This invention does not limit the specific bonding method.

[0054] Optionally, the object side and the image side of the first lens 10 are both concave; the object side and the image side of the second lens 20 are both convex; the object side of the third lens 30 is convex and the image side is concave; the object side and the image side of the fourth lens 40 are both concave; the object side and the image side of the fifth lens 50 are both convex; the object side of the sixth lens 60 is concave and the image side is convex; the object side of the seventh lens 70 is concave and the image side is convex.

[0055] Herein, the object side of the lens can be understood as the surface of the lens closer to the object plane, and the image side of the lens can be understood as the surface of the lens closer to the image plane. The object side of the lens being concave can be understood as the object side of the lens being recessed towards the object plane at the position near the optical axis, and the object side of the lens being convex can be understood as the object side of the lens being protruded towards the object plane at the position near the optical axis; the image side of the lens being concave can be understood as the image side of the lens being recessed towards the image plane at the position near the optical axis, and the image side of the lens being convex can be understood as the image side of the lens being protruded towards the image plane at the position near the optical axis.

[0056] In this embodiment, by reasonably setting the surface shapes of each lens, it is possible to ensure that the edge ray trend is smoother, improve the relative illuminance between the edge image and the central image, and enhance the imaging effect. The relative illuminance between the edge image and the central image in the embodiment of the present invention can reach 57%, ensuring the consistency of imaging brightness.

[0057] Optionally, the focal length f1 of the first lens 10, the focal length f2 of the second lens 20, and the focal length f3 of the third lens 30 satisfy: 0.8 < f1 / f + f2 / f + f3 / f < 1.1; wherein, f is the overall focal length of the industrial line scan lens.

[0058] Herein, the first lens 10 has a negative optical power, and the second lens 20 and the third lens 30 both have positive optical powers, that is, the focal length f1 of the first lens 10 is negative, and the focal lengths f2 of the second lens 20 and f3 of the third lens 30 are both positive. By making the focal length f1 of the first lens 10, the focal length f2 of the second lens 20, and the focal length f3 of the third lens 30 satisfy the above relationship, it is beneficial to correct the chromatic aberration of the industrial line scan lens, thereby improving the resolution ability of the industrial line scan lens.

[0059] Optionally, the focal length f3 of the third lens 30 satisfies: 0.9 < f3 / f < 1.3; wherein, f is the overall focal length of the industrial line scan lens. Thus, by making the third lens 30 satisfy the above relationship, it is beneficial to correct the distortion and field curvature of the optical system of the industrial line scan lens.

[0060] Optionally, the Abbe number Vd1 of the first lens 10, the Abbe number Vd2 of the second lens 20, and the Abbe number Vd3 of the third lens 30 satisfy: 80 < Vd3 + Vd2 - Vd1 < 100.

[0061] In this embodiment, by making the Abbe number Vd1 of the first lens 10, the Abbe number Vd2 of the second lens 20, and the Abbe number Vd3 of the third lens 30 satisfy the above relationship, the third lens 30 can have a relatively high Abbe number. The third lens 30 with a relatively high Abbe number cooperates with the first lens 10 and the second lens, which is conducive to correcting the chromatic aberration of the system and improving the imaging clarity.

[0062] Optionally, the focal length f4 of the fourth lens 40, the refractive index Nd4 of the fourth lens 40, the focal length f5 of the fifth lens 50, and the refractive index Nd5 of the fifth lens 50 satisfy: 0 < (ND5 - ND4) * (f5 / f - f4 / f) < 0.06; where f is the overall focal length of the industrial line scan lens. With such a setting, it is conducive to correcting the optical system distortion and field curvature of the industrial line scan lens.

[0063] Optionally, the focal length f6 of the sixth lens 60 and the focal length f7 of the seventh lens 70 satisfy: 0.1 < |f6 / f + f7 / f| < 0.14; where f is the overall focal length of the industrial line scan lens. With such a setting, it is conducive to the smooth transition of light on the surfaces of the subsequent lenses, reducing the incident angle and the exit angle, thereby being able to reduce the sensitivity of the optical system of the industrial line scan lens and improving the relative illumination and production yield of the optical system.

[0064] Optionally, the refractive index of the sixth lens 60 satisfies: 1.9 < ND6. In this way, the sixth lens 60 can have a relatively high refractive index, which is conducive to reducing the refraction and scattering of light, thereby improving the imaging quality of the industrial line scan lens.

[0065] Optionally, the maximum semi-aperture among the semi-apertures of each lens is SDmax; where 0.6 < 2 * SDmax / Hmax < 0.67, and Hmax is the maximum image height of the industrial line scan lens. With such a setting, it is conducive to reducing the volume of the overall optical system, enabling the finished lens to be adapted to more usage environments, and reducing the cost of each lens.

[0066] Optionally, at the reference object distance of the industrial line scan lens, the distance from the image side of the seventh lens 70 to the image plane of the industrial line scan lens is BFL; where 0.71 < BFL / f < 0.76, and f is the overall focal length of the industrial line scan lens.

[0067] Herein, the reference object distance can be understood as the commonly used object distance of the industrial line scan lens, and can be specifically designed according to actual needs. In an exemplary embodiment, the reference object distance of the industrial line scan lens can be 350 mm.

[0068] In this embodiment, by making the distance BFL from the image side of the seventh lens 70 to the image plane of the industrial line scan lens satisfy the above relationship with the overall focal length f of the industrial line scan lens, it is beneficial to reduce the size of the optical system of the industrial line scan lens, so that the industrial line scan lens can be adapted to more usage environments and reduce the material cost of the lens.

[0069] Based on the above embodiments, optionally, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, the sixth lens 60 and the seventh lens 70 are all glass spherical lenses.

[0070] Among them, spherical lenses are characterized by a constant curvature from the center to the periphery, ensuring a simple lens setup. Meanwhile, glass lenses have a low coefficient of thermal expansion and good stability, giving glass spherical lenses higher thermal stability. This allows industrial line-scan lenses to maintain good resolution over a wide temperature range (-40℃ to 80℃) when handling high optical power. Furthermore, compared to plastic aspherical lenses, glass offers a wider range of material choices, with more freedom in selecting the refractive index and Abbe constant. This allows for better control over higher aberrations and chromatic aberrations, meeting the needs of use under complex conditions.

[0071] In summary, this embodiment of the utility model employs seven lenses with optical power to form an industrial line scan lens. By rationally allocating the optical power of each lens and selecting appropriate materials and designing the shape of each lens, the industrial line scan lens can simultaneously meet the requirements of small size, low distortion, large target surface, high relative illumination, and large aperture. This allows the industrial line scan lens to focus quickly and clearly at different working distances. For example, within a working range of 200mm-900mm, the focal length of the industrial line scan lens can be around 60mm.

[0072] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of an industrial line scan lens applicable to the above-described embodiments.

[0073] In one feasible embodiment, Table 1 details a feasible implementation method. Figure 1 The specific optical and physical parameters of the industrial line scan lens are shown.

[0074] Table 1. Design of optical physical parameters for an industrial linear scanning lens.

[0075] Scope of protection Example 1 0.8<f1 / f+f2 / f+f3 / f<1.1 0.888 80<VD3+VD2-VD1<100 84.600 0.9<f3 / f<1.3 0.984 0<(ND5-ND4)*(f5 / f-f4 / f)<0.06 0.053 0.1<|f6 / f+f7 / f|<0.14 1.950 1.9<ND6 0.1324 0.6<2*SDmax / H<0.67 0.6654 0.71<BFL / f<0.76 0.7187

[0076] The maximum image height Hmax of the industrial line scan lens in this embodiment is 58mm, the image-side aperture number F# is 4.1, and the focal length f of the industrial line scan lens can reach 62mm.

[0077] Table 2 shows the design parameters of each lens in an industrial line scan lens, including surface type, radius of curvature, thickness, and material, which correspond to those in Table 1.

[0078] Table 2. Parameter Design of Each Lens in Industrial Line Scan Lenses

[0079] Face number Surface type radius of curvature thickness Refractive index Abbe number Half-caliber 0 surface unlimited 350.000 1 spherical Infinity 2.482 19.258 2 spherical -73.2770 1.183 1.6900 29.00 19.297 3 spherical 184.4204 3.774 1.9400 32.00 18.901 4 spherical -101.0501 2.549 18.812 5 spherical 21.3835 9.808 1.5000 81.60 14.789 6 spherical 60.4393 9.675 11.964 STO spherical Infinity 2.000 5.150 8 spherical Infinity 6.800 4.840 9 spherical -16.2596 1.193 1.8500 22.90 7.390 10 spherical 82.7723 6.808 1.9500 32.00 9.255 11 spherical -19.4150 1.412 10.752 12 spherical -14.9723 3.429 1.6400 34.00 10.780 13 spherical -31.4779 0.406 13.622 14 spherical -73.3175 3.393 1.9500 32.00 14.904 15 spherical -31.7849 44.560 15.311 16 Image unlimited -

[0080] The industrial line scan lens of this embodiment includes a first lens 10, a second lens 20, a third lens 30, a vignetting stop 80, an aperture stop 90, a fourth lens 40, a fifth lens 50, a sixth lens 60, and a seventh lens 70 arranged sequentially along the optical axis from the object side to the image side. The surface numbers are based on the surface order of each lens, where "1" represents the object side of the first lens 10, "2" represents the image side of the first lens 10, and so on; "STO" represents the aperture stop of the lens; the radius of curvature represents the degree of curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane, where "Infinity" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the axial distance between the central surfaces of the current and next surfaces; the refractive index represents the ability of the material between the current and next surfaces to deflect light, with a space indicating 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 and next surfaces, with a space indicating that the current position is air.

[0081] Table 3 shows the thickness of the focusing interval for an industrial line scan lens corresponding to Table 1 at different object distances.

[0082] Table 3 Focusing Interval Thickness at Different Object Distances

[0083] Object distance 200mm 900mm 15-sided thickness 54.728mm 37.14mm

[0084] Figure 2 yes Figure 1 The diagram shows the MTF (Mean Transmission Function) of an industrial linear scanning lens across the visible light spectrum. The MTF is one of the most commonly used and authoritative evaluation methods in modern optical design. The horizontal axis represents the spatial frequencies of the line pairs in object space imaged onto the image plane by the optical system, in periods / mm. The vertical axis represents the magnitude of the optical transfer function. The diagram shows the trend of the optical transfer function along the meridional (T) and sagittal (S) directions corresponding to different fields of view (0.00mm, 8.00mm, 14.00mm, 22.00mm, 28.00mm, and 29.00mm in the diagram) directions as the spatial frequency increases. The ideal curve is a straight line coinciding with the system's diffraction limit, indicating that the geometric aberrations of the light rays at all positions are less than the wave phase aberration caused by the physical limitations of the system itself, and can be ignored. Figure 2It can be seen that the optical transfer function of this industrial line scan lens is greater than 0.2 at 70 lp / mm for each field of view, thus achieving high resolution in visible light environments.

[0085] Figure 3 yes Figure 1 The diagram shows the relative illumination curve of an industrial line scan lens. The horizontal axis represents the half-field height (in mm), and the vertical axis represents the relative illumination. Figure 3 As shown, the industrial line scan lens has high relative illumination under different fields of view, and the relative illumination is greater than 60% in the maximum field of view.

[0086] Figure 4 yes Figure 1 The diagram shows the field curvature distortion curve of an industrial line scan lens. In the coordinate system on the left side of the diagram, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height, which has no unit. Figure 4 It can be seen that the industrial line scan lens provided in this embodiment effectively controls the field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is small. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit; from Figure 4 As can be seen, the maximum distortion of the lens provided in this embodiment is controlled within 0.5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0087] In another feasible embodiment, Figure 5 This is a schematic diagram of another industrial line scan lens provided in this embodiment of the present invention. Table 4 describes in detail another feasible implementation method. Figure 5 The specific optical and physical parameters of the industrial line scan lens are shown.

[0088] Table 4. Another optical physical parameter design for industrial line scan lenses.

[0089] Scope of protection Example 2 0.8<f1 / f+f2 / f+f3 / f<1.1 0.911 80<VD3+VD2-VD1<100 85.800 0.9<f3 / f<1.3 1.014 0<(ND5-ND4)*(f5 / f-f4 / f)<0.06 0.036 0.1<|f6 / f+f7 / f|<0.14 1.950 1.9<ND6 0.1089 0.6<2*SDmax / H<0.67 0.6027 0.71<BFL / f<0.76 0.7457

[0090] The maximum image height Hmax of the industrial line scan lens in this embodiment is 58mm, the image-side aperture number F# is 4.1, and the focal length f of the industrial line scan lens can reach 58mm.

[0091] Table 5 shows the design parameters of each lens in another type of industrial line scan lens, corresponding to Table 4, including surface type, radius of curvature, thickness, and material.

[0092] Table 5. Another parameter design for each lens in an industrial line scan lens.

[0093] Face number Surface type radius of curvature thickness Refractive index Abbe number Half-caliber 0 surface Infinity 350.000 1 Standard surface Infinity 3.215 2 Standard surface -57.9306 1.114 1.7200 28.00 17.441 3 Standard surface 389.8223 3.539 1.9500 31.80 17.145 4 Standard surface -71.6509 0.100 17.071 5 Standard surface 19.2190 6.710 1.5000 82.00 13.689 6 Standard surface 48.9063 10.216 12.181 7 Standard surface Infinity 2.000 4.970 STO Standard surface Infinity 6.800 4.707 9 Standard surface -14.0647 2.557 1.8800 24.00 7.250 10 Standard surface 90.1919 5.130 1.9500 32.00 10.304 11 Standard surface -18.4370 1.605 10.863 12 Standard surface -14.3621 0.998 1.6400 34.00 10.912 13 Standard surface -23.5934 0.100 12.520 14 Standard surface -59.7848 3.286 1.950 32.00 13.930 15 Standard surface -28.2255 43.251 14.373 16 Image unlimited -

[0094] The industrial line scan lens of this embodiment includes a first lens 10, a second lens 20, a third lens 30, a vignetting stop 80, an aperture stop 90, a fourth lens 40, a fifth lens 50, a sixth lens 60, and a seventh lens 70 arranged sequentially along the optical axis from the object side to the image side. The surface numbers are based on the surface order of each lens, where "1" represents the object side of the first lens 10, "2" represents the image side of the first lens 10, and so on; "STO" represents the aperture stop of the lens; the radius of curvature represents the degree of curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane, where "Infinity" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the axial distance between the central surfaces of the current and next surfaces; the refractive index represents the ability of the material between the current and next surfaces to deflect light, with a space indicating 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 and next surfaces, with a space indicating that the current position is air.

[0095] Table 3 shows the thickness of the focusing interval for an industrial line scan lens corresponding to Table 1 at different object distances.

[0096] Table 3 Focusing Interval Thickness at Different Object Distances

[0097] Object distance 200mm 900mm 15-sided thickness 52.217mm 36.738mm

[0098] Figure 6 yes Figure 5 The diagram shows the MTF (Mean Transmission Function) of an industrial linear scanning lens across the visible light spectrum. The MTF is one of the most commonly used and authoritative evaluation methods in modern optical design. The horizontal axis represents the spatial frequencies of the line pairs in object space imaged onto the image plane by the optical system, in periods / mm. The vertical axis represents the magnitude of the optical transfer function. The diagram shows the trend of the optical transfer function along the meridional (T) and sagittal (S) directions corresponding to different fields of view (0.00mm, 8.00mm, 14.00mm, 22.00mm, 28.00mm, and 29.00mm in the diagram) directions as the spatial frequency increases. The ideal curve is a straight line coinciding with the system's diffraction limit, indicating that the geometric aberrations of the light rays at all positions are less than the wave phase aberration caused by the physical limitations of the system itself, and can be ignored. Figure 6 It can be seen that the optical transfer function of this industrial line scan lens is greater than 0.2 at 70 lp / mm for each field of view, thus achieving high resolution in visible light environments.

[0099] Figure 7 yes Figure 5 The diagram shows the relative illumination curve of an industrial line scan lens. The horizontal axis represents the half-field height (in mm), and the vertical axis represents the relative illumination. Figure 7 As shown, the industrial line scan lens has high relative illumination under different fields of view, and the relative illumination is greater than 50% in the maximum field of view.

[0100] Figure 8 yes Figure 5 The diagram shows the field curvature distortion curve of an industrial line scan lens. In the coordinate system on the left side of the diagram, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height, which has no unit. Figure 8 It can be seen that the industrial line scan lens provided in this embodiment effectively controls the field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is small. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit; from Figure 8 As can be seen, the maximum distortion of the lens provided in this embodiment is controlled within 0.5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0101] In yet another feasible embodiment, Figure 9 This is a schematic diagram of another industrial line scan lens provided by this utility model embodiment. Table 7 describes in detail another feasible implementation method. Figure 9 The specific optical and physical parameters of the industrial line scan lens are shown.

[0102] Table 7. Another optical physical parameter design for industrial line scan lenses.

[0103] Scope of protection Example 3 0.8<f1 / f+f2 / f+f3 / f<1.1 1.079 80<VD3+VD2-VD1<100 98.000 0.9<f3 / f<1.3 1.241 0<(ND5-ND4)*(f5 / f-f4 / f)<0.06 0.056 0.1<|f6 / f+f7 / f|<0.14 1.950 1.9<ND6 0.1190 0.6<2*SDmax / H<0.67 0.6586 0.71<BFL / f<0.76 0.7591

[0104] The maximum image height Hmax of the industrial line scan lens in this embodiment is 58mm, the image-side aperture number F# is 4.1, and the focal length f of the industrial line scan lens can reach 60mm.

[0105] Table 8 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in another type of industrial line scan lens, corresponding to Table 7.

[0106] Table 8. Another parameter design for each lens in an industrial line scan lens.

[0107] Face number Surface type radius of curvature thickness Refractive index Abbe number Half-caliber 0 surface unlimited 350.000 1 Standard surface Infinity 0.741 19.051 2 Standard surface -209.5641 10.165 1.6900 29.00 19.104 3 Standard surface 56.9108 3.913 1.9400 32.00 16.706 4 Standard surface -463.0649 0.099 16.490 5 Standard surface 19.3127 9.990 1.4300 95.00 13.727 6 Standard surface 41.0411 8.055 10.385 7 Standard surface Infinity 2.100 5.080 STO Standard surface Infinity 6.800 4.853 9 Standard surface -15.5376 0.984 1.8500 23.10 7.420 10 Standard surface 166.0612 4.143 1.9500 32.30 9.171 11 Standard surface -17.3845 1.036 9.668 12 Standard surface -13.9398 4.640 1.6400 34.00 9.689 13 Standard surface -26.8942 0.092 12.819 14 Standard surface -79.1816 2.969 1.9500 32.00 14.112 15 Standard surface -33.6665 45.545 14.482 16 Image unlimited -

[0108] The industrial line scan lens of this embodiment includes a first lens 10, a second lens 20, a third lens 30, a vignetting stop 80, an aperture stop 90, a fourth lens 40, a fifth lens 50, a sixth lens 60, and a seventh lens 70 arranged sequentially along the optical axis from the object side to the image side. The surface numbers are based on the surface order of each lens, where "1" represents the object side of the first lens 10, "2" represents the image side of the first lens 10, and so on; "STO" represents the aperture stop of the lens; the radius of curvature represents the degree of curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane, where "Infinity" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the axial distance between the central surfaces of the current and next surfaces; the refractive index represents the ability of the material between the current and next surfaces to deflect light, with a space indicating 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 and next surfaces, with a space indicating that the current position is air.

[0109] Table 3 shows the thickness of the focusing interval for an industrial line scan lens corresponding to Table 1 at different object distances.

[0110] Table 3 Focusing Interval Thickness at Different Object Distances

[0111] Object distance 200mm 900mm 15-sided thickness 55.012mm 38.612mm

[0112] Figure 10 yes Figure 9 The diagram shows the MTF (Mean Transmission Function) of an industrial linear scanning lens across the visible light spectrum. The MTF is one of the most commonly used and authoritative evaluation methods in modern optical design. The horizontal axis represents the spatial frequencies of the line pairs in object space imaged onto the image plane by the optical system, in periods / mm. The vertical axis represents the magnitude of the optical transfer function. The diagram shows the trend of the optical transfer function along the meridional (T) and sagittal (S) directions corresponding to different fields of view (0.00mm, 8.00mm, 14.00mm, 22.00mm, 28.00mm, and 29.00mm in the diagram) directions as the spatial frequency increases. The ideal curve is a straight line coinciding with the system's diffraction limit, indicating that the geometric aberrations of the light rays at all positions are less than the wave phase aberration caused by the physical limitations of the system itself, and can be ignored. Figure 10 It can be seen that the optical transfer function of this industrial line scan lens is greater than 0.2 at 70 lp / mm for each field of view, thus achieving high resolution in visible light environments.

[0113] Figure 11 yes Figure 9 The diagram shows the relative illumination curve of an industrial line scan lens. The horizontal axis represents the half-field height (in mm), and the vertical axis represents the relative illumination. Figure 11 As shown, the industrial line scan lens has high relative illumination under different fields of view, and the relative illumination is greater than 55% in the maximum field of view.

[0114] Figure 12 yes Figure 9 The diagram shows the field curvature distortion curve of an industrial line scan lens. In the coordinate system on the left side of the diagram, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height, which has no unit. Figure 12 It can be seen that the industrial line scan lens provided in this embodiment effectively controls the field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is small. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in %; the vertical axis represents the normalized image height, which has no unit; from Figure 12 As can be seen, the maximum distortion of the lens provided in this embodiment is controlled within 0.5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0115] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. An industrial line scan lens, characterized in that, Comprising: A first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a vignetting stop, an aperture stop, a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, and a seventh lens with positive optical power arranged in sequence along the optical axis from the object side to the image side; The first lens and the second lens form a doublet lens; the fourth lens and the fifth lens form a doublet lens; Wherein, the first lens, the second lens, the third lens, the vignetting stop, the aperture stop, the fourth lens, the fifth lens, the sixth lens, and the seventh lens move as a whole for focusing; the aperture of the aperture stop is variable.

2. The industrial line scan lens according to claim 1, wherein The object side surface and the image side surface of the first lens are both concave surfaces; The object side surface and the image side surface of the second lens are both convex surfaces; The object side surface of the third lens is a convex surface and the image side surface is a concave surface; The object side surface and the image side surface of the fourth lens are both concave surfaces; The object side surface and the image side surface of the fifth lens are both convex surfaces; The object side surface of the sixth lens is a concave surface and the image side surface is a convex surface; The object side surface of the seventh lens is a concave surface and the image side surface is a convex surface.

3. The industrial line scan lens according to claim 1, characterized in that, The focal length f1 of the first lens, the focal length f2 of the second lens, and the focal length f3 of the third lens satisfy: 0.8 < f1 / f + f2 / f + f3 / f < 1.1; wherein, f is the overall focal length of the industrial line scan lens.

4. The industrial line scan lens according to claim 1, characterized in that, The focal length f3 of the third lens satisfies: 0.9 < f3 / f < 1.3; wherein, f is the overall focal length of the industrial line scan lens.

5. The industrial line scan lens according to claim 1, characterized in that, The Abbe number Vd1 of the first lens, the Abbe number Vd2 of the second lens, and the Abbe number Vd3 of the third lens satisfy: 80 < Vd3 + Vd2 - Vd1 < 100.

6. The industrial line scan lens according to claim 1, characterized in that, The focal length f4 of the fourth lens, the refractive index Nd4 of the fourth lens, the focal length f5 of the fifth lens, and the refractive index Nd5 of the fifth lens satisfy: 0 < (ND5 - ND4) * (f5 / f - f4 / f) < 0.06; wherein, f is the overall focal length of the industrial line scan lens.

7. The industrial line scan lens according to claim 1, characterized in that, The focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.1 < |f6 / f + f7 / f| < 0.14; wherein, f is the overall focal length of the industrial line scan lens.

8. The industrial line scan lens according to claim 1, characterized in that, The refractive index of the sixth lens satisfies: 1.9 < ND6.

9. The industrial line scan lens according to claim 1, characterized in that, The maximum semi-aperture among the semi-apertures of each lens is SDmax; Wherein, 0.6 < 2 * SDmax / Hmax < 0.67, and Hmax is the maximum image height of the industrial line scan lens.

10. The industrial line scan lens according to claim 1, characterized in that, At the reference object distance of the industrial line scan lens, the distance from the image side surface of the seventh lens to the image plane of the industrial line scan lens is BFL; Wherein, 0.71 < BFL / f < 0.76, and f is the overall focal length of the industrial line scan lens.

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