Optical lens, camera device and industrial detection equipment with same

Abstract

The application discloses an optical lens, a camera device and industrial detection equipment with the same, which are characterized by the following: eight lenses with optical powers of positive, positive, negative, negative, positive, positive, negative and positive are arranged in sequence along the optical axis from the object plane to the image plane; the sum of the air intervals of the optical axis between the first lens and the eighth lens is between 5.6mm and 18.5mm; the lens satisfies the following conditions: 30mm≤ f ≤38mm, 12.5mm≤2× D 1≤15.6mm, 10≤ Y m / Y 1≤16.5, wherein, f F is the total focal length of the lens, 2× D 1 is the effective diameter of the first lens, Y m H is the image height corresponding to the maximum field of view, Y 1 is the image height of the lens corresponding to a half field of view of 1°. The optical power distribution of the application is beneficial to better control coma, field curvature and distortion, and realizes the design of a medium-long focal length optical lens with excellent full field of view uniformity in a compact structure.

Description

Technical Field

[0001] This invention relates to the field of optics, and more particularly to an optical lens, a camera device, and an industrial inspection device having the same, which optimizes the uniformity of the entire field of view. Background Technology

[0002] With the widespread application of high-resolution image sensors (such as full-frame CMOS), fields such as photography, film, and industrial vision have placed higher demands on the imaging quality of optical lenses. In traditional lens design, especially at standard focal lengths (such as 35mm), priority is usually given to pursuing the ultimate resolution of the center field of view. This results in insufficient correction of off-axis aberrations (such as field curvature, astigmatism, and coma), which significantly reduces the modulation transfer function (MTF) of the edge field of view and leads to poor image uniformity.

[0003] In existing technologies, while simplified structures (such as 6-8 lenses) can control cost and size, it is difficult to balance center sharpness and edge image quality in the image. Increasing the number of lenses, if the optical power is not properly distributed, will introduce too many advanced aberrations and increase the size of the lens.

[0004] The disclosure of the above background technical content is only for the purpose of assisting in understanding the concept and technical solution of this application, and does not necessarily provide technical instruction. Summary of the Invention

[0005] The purpose of this invention is to provide a medium-to-long telephoto optical lens design that achieves excellent uniformity across the entire field of view in a compact structure.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An optical lens comprising eight lenses of optical power, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis from the object plane to the image plane, wherein: The optical powers of the first to the eighth lenses are positive, positive, negative, negative, positive, positive, negative, positive, respectively; The sum of the air gaps between the optical axes of the first lens and the eighth lens is between 5.5 mm and 18.6 mm; The optical lens satisfies: 30mm≤ f ≤38mm, 12.5mm≤2× D 1≤15.6mm, 10≤ Y m / Y 1≤16.5, where, f For the entire focal length of the lens, 2× D 1 is the effective diameter of the first lens. Y m The image height corresponding to the maximum field of view.Y 1 represents the lens image height when the half field of view is 1°.

[0007] Furthermore, based on any one or a combination of the aforementioned technical solutions, the focal length of each lens satisfies the following condition: 0.74 ≤ f 1 / f ≤1.69, 0.3≤ f 2 / f ≤0.81, -0.38≤ f 3 / f ≤-0.15, -0.39≤ f 4 / f ≤-0.2, 0.2≤ f 5 / f ≤0.48, 0.75≤ f 6 / f ≤1.88, -1.9≤ f 7 / f ≤-0.68, 0.6≤ f 8 / f ≤1.3, where, f 1 is the focal length of the first lens ，f 2 represents the focal length of the second lens. f 3 is the focal length of the third lens ，f 4 represents the focal length of the fourth lens. f 5 is the focal length of the fifth lens. f 6 is the focal length of the sixth lens. f 7 represents the focal length of the seventh lens. f 8 represents the focal length of the eighth lens.

[0008] Furthermore, based on any one or a combination of the aforementioned technical solutions, the optical lens satisfies: 20° ≤ Fov ≤34°, 45mm≤ TTL ≤62mm, where, Fov The maximum field of view of the lens. TTL It is the distance on the optical axis from the vertex of the object side of the first lens to the imaging surface.

[0009] Furthermore, based on any one or a combination of the aforementioned technical solutions, the object side of the second lens has a convex structure near the optical axis; The image-side surface of the third lens has a concave structure near the optical axis; The object-side and image-side surfaces of the fourth lens are both concave near the optical axis. The object-side and image-side surfaces of the fifth and eighth lenses are both convex near the optical axis. The image-side surface of the sixth lens has a convex structure near the optical axis; The image-side surface of the seventh lens has a concave structure near the optical axis.

[0010] Furthermore, based on any one or a combination of the aforementioned technical solutions, the ratio of the larger of the absolute value of the object-side radius of curvature and the absolute value of the image-side radius of curvature of the first lens to the smaller of the latter is between 4 and 8. The radius of curvature of the object-side surface of the second lens is between 11.5 mm and 14 mm; The radius of curvature of the image-side surface of the third lens is between 9.2 mm and 10.3 mm; The ratio of the object-side radius of curvature of the fourth lens to the image-side radius of curvature is between -0.86 and -0.65. The object-side radius of curvature of the fifth lens is between 14.5 mm and 18.8 mm, and the image-side radius of curvature is between -34 mm and -15.5 mm. The object-side radius of curvature of the eighth lens is between 24 mm and 52 mm, and the image-side radius of curvature is between -53 mm and -36 mm.

[0011] Furthermore, in accordance with any or a combination of the aforementioned technical solutions, the optical axis distance from the object side of the first lens to the image side of the third lens is between 6 mm and 12.6 mm, and the sum of the air gaps between the optical axes of the first lens and the third lens is between 0.05 mm and 1 mm. And / or, the center thickness of the first lens is between 1.1 mm and 5.25 mm, the center thickness of the second lens is between 2 mm and 5.15 mm, and the center thickness of the third lens is between 0.7 mm and 4.8 mm.

[0012] Furthermore, based on any or a combination of the aforementioned technical solutions, the optical axis distance from the object side of the fourth lens to the image side of the eighth lens is between 8 mm and 14.8 mm. The optical axis distance from the object side of the seventh lens to the image side of the eighth lens is between 3 mm and 6.8 mm. The optical axis distance from the image side surface to the imaging surface of the eighth lens is between 19.9 mm and 33 mm; The optical lens satisfies: 19.9≤ bfl ≤33.6, 0.3≤ bfl / f ≤1.1, 0.3≤ bfl / TTL ≤0.6, 1.2≤ TTL / f ≤1.9, where, bfl The rear focal length of the lens. TTL It is the distance on the optical axis from the vertex of the object side of the first lens to the imaging surface.

[0013] Furthermore, based on any one or a combination of the aforementioned technical solutions, among the eight lenses with optical power, the lens with the smallest central thickness is the seventh lens. The center thickness of the sixth lens is between 1.4 mm and 1.7 mm, the center thickness of the seventh lens is between 0.7 mm and 0.9 mm, and the center thickness of the eighth lens is between 1.9 mm and 3.2 mm.

[0014] Furthermore, based on any one or a combination of the aforementioned technical solutions, the optical lens satisfies: 0.02 ≤ Fov / (2× D 1) / TTL ≤0.052, 0.5≤ Fov / Y m / 2≤1.45, and 0.28≤ Y m / TTL ≤0.4, 1.2≤ TTL / f ≤1.9, where, Fov The maximum field of view of the lens. TTL It is the distance on the optical axis from the vertex of the object side of the first lens to the imaging surface.

[0015] Furthermore, following any one or a combination of the aforementioned technical solutions, the second lens and the third lens constitute a cemented lens, and the optical lens satisfies: 1.5 ≤ -f 2 / f 3≤2.44, 35≤vd2-vd1≤60, 35≤vd2-vd3≤60, where, f 2 represents the focal length of the second lens. f 3 is the focal length of the third lens, vd1 is the Abbe constant of the first lens, vd2 is the Abbe constant of the second lens, and vd3 is the Abbe constant of the third lens; And / or, the fourth lens and the fifth lens constitute a cemented lens, and the optical lens satisfies: 14.6mm ≤ r 42 ≤18.5mm, 0.7≤ -f 4 / f 5≤1.1, 18≤|vd6-vd5|≤38, where, r 42 Let be the radius of curvature of the image-side surface of the fourth lens. f 4 represents the focal length of the fourth lens. f 5 is the focal length of the fifth lens, vd6 is the Abbe constant of the sixth lens, and vd5 is the Abbe constant of the fifth lens.

[0016] Furthermore, based on any one or a combination of the aforementioned technical solutions, among the eight lenses with optical power, the positive lens with the highest optical power is the fifth lens, whose focal length is between 9.5mm and 16.2mm. The object-side radius of curvature of the fifth lens is between 14.2 mm and 19 mm, and the image-side radius of curvature is between -34 mm and -15.5 mm. The negative lens with the highest optical power is either the third or fourth lens, with a focal length between -13mm and -5.5mm.

[0017] Furthermore, based on any one or a combination of the aforementioned technical solutions, the refractive index of the eight-element lens with optical power is between 1.35 and 2.16, wherein the difference between the maximum and minimum refractive index is between 0.4 and 0.52.

[0018] Furthermore, based on any one or a combination of the aforementioned technical solutions, all eight lenses with optical power are spherical mirrors.

[0019] Furthermore, based on any or a combination of the aforementioned technical solutions, the optical axis distance between the image-side surface of the sixth lens and the object-side surface of the seventh lens is adjustable within the range of 0.2 mm to 12.5 mm; And / or, the optical lens further includes a filter disposed between the eighth lens and the imaging surface, the optical axis distance between the filter and the imaging surface being adjustable in the range of 0.8 mm to 13 mm.

[0020] Furthermore, based on any one or a combination of the aforementioned technical solutions, the lens satisfies: 60≤ Y 1×180 / pi ≤100; And / or, 0.28≤2× D 1 / f ≤0.55; And / or, 17.5mm≤ Y m ≤18.6mm; And / or, 1.05mm≤ Y 1≤1.88mm.

[0021] According to another aspect of the present invention, a camera device is provided, including an electronic photosensitive element and an optical lens as described above.

[0022] According to another aspect of the present invention, an industrial inspection device is provided, including an image processor and a camera device as described above, wherein the camera device may be a line scan camera or an area scan camera.

[0023] The beneficial effects of the technical solution provided by this invention are as follows: a. The lens employs an 8-element optical power arrangement with a "positive-positive-negative-negative-positive-positive-negative-positive" configuration. The front group consists of two positive lenses, which are beneficial for light collection and control of the entrance pupil position. The two middle negative lenses are used to correct spherical aberration and chromatic aberration, and can also share the optical power, reducing the burden on subsequent lenses. The middle and rear groups again have a double positive, negative, and positive optical power structure, which helps to correct field curvature and astigmatism, while maintaining image plane flatness. This optical power distribution is beneficial for aberration correction across the entire field of view, especially for coma, field curvature, and distortion. b. The air gap between adjacent lenses is compact but not excessively compressed, resulting in strong optical power coupling to correct off-axis advanced aberrations, which further contributes to the improvement of uniformity performance across the entire field of view; c. The overall focal length is between 30.5mm and 38mm, the effective diameter of the first lens is between 12.5mm and 15.6mm, the incident angle of light in the edge field of view is large, which is conducive to achieving a reasonable entrance pupil size and can prevent serious vignetting or coma caused by large-angle light. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the lens arrangement of the lens provided in the first embodiment of the present invention; Figure 2 The image shows the MTF frequency curve of the lens in the first embodiment of the present invention at an object distance of 250mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 3 The image shows the MTF frequency curve of the lens in the first embodiment of the present invention at an object distance of 2000mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 4 The image shows the MTF frequency curve of the lens in the first embodiment of the present invention at an object distance of 150mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 5 The image shows the relative illumination curve of the lens in the first embodiment of the present invention at an object distance of 250mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 6 The image shows the relative illumination curve of the lens in the first embodiment of the present invention at an object distance of 2000mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 7 The image shows the relative illumination curve of the lens in the first embodiment of the present invention at an object distance of 150mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 8 The distortion curve of the lens in the first embodiment of the present invention is shown at an object distance of 250mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 9 The distortion curve of the lens in the first embodiment of the present invention is shown at an object distance of 2000mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 10 The distortion curve of the lens in the first embodiment of the present invention is shown at an object distance of 150mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 11 This is a schematic diagram of the lens arrangement of a lens provided in the second embodiment of the present invention; Figure 12 The image shows the MTF frequency curve of the lens in the second embodiment of the present invention at an object distance of 250mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 13 The image shows the MTF frequency curve of the lens in the second embodiment of the present invention at an object distance of 2000mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 14 The image shows the MTF frequency curve of the lens in the second embodiment of the present invention at an object distance of 150mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 15 The image shows the relative illumination curve of the lens in the second embodiment of the present invention at an object distance of 250mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 16 The image shows the relative illumination curve of the lens in the second embodiment of the present invention at an object distance of 2000mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 17The image shows the relative illumination curve of the lens in the second embodiment of the present invention at an object distance of 150mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 18 The distortion curve of the lens in the second embodiment of the present invention is shown at an object distance of 250mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 19 The distortion curve of the lens in the second embodiment of the present invention is shown at an object distance of 2000mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 20 The distortion curve of the lens in the second embodiment of the present invention is shown at an object distance of 150mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 21 This is a schematic diagram of the lens arrangement of a lens provided in the third embodiment of the present invention; Figure 22 The image shows the MTF frequency curve of the lens in the third embodiment of the present invention at an object distance of 250mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 23 The image shows the MTF frequency curve of the lens in the third embodiment of the present invention at an object distance of 2000mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 24 The image shows the MTF frequency curve of the lens in the third embodiment of the present invention at an object distance of 150mm. The horizontal axis represents the spatial frequency (in LP / mm), and the vertical axis represents the OTF modulus (dimensionless). Figure 25 The image shows the relative illumination curve of the lens in the third embodiment of the present invention at an object distance of 250mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 26 The image shows the relative illumination curve of the lens in the third embodiment of the present invention at an object distance of 2000mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 27 The image shows the relative illumination curve of the lens in the third embodiment of the present invention at an object distance of 150mm. The horizontal axis represents the Y field of view (in mm), and the vertical axis represents the relative illumination (dimensionless). Figure 28The distortion curve of the lens in the third embodiment of the present invention is shown at an object distance of 250mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 29 The distortion curve of the lens in the third embodiment of the present invention is shown at an object distance of 2000mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Figure 30 The distortion curve of the lens in the third embodiment of the present invention is shown at an object distance of 150mm. The horizontal axis is the distortion percentage (in %), and the vertical axis is the normalized image height (dimensionless). Detailed Implementation

[0026] 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 of the present invention. 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 scope of protection of the present invention.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0028] A focal length of around 35mm falls into the mid-to-long telephoto range. Compared to telephoto lenses, such lenses retain more environmental information; compared to wide-angle lenses, they focus more on distant structures (eliminating cluttered backgrounds). These lenses approximate the human monocular perspective, offering controllable image distortion and allowing for larger apertures. In traditional lens designs, a larger aperture often results in edge image quality being limited by size. One aspect of this invention aims to provide a lens with excellent uniformity across the entire field of view, pursuing consistent resolution between the center and edges.

[0029] by Figure 1For example, the lens arrangement of the first embodiment is shown, where L1 represents the first lens, L2 represents the second lens, L3 represents the third lens, L4 represents the aperture stop, L5 represents the fourth lens, L6 represents the fifth lens, L7 represents the sixth lens, L8 represents the seventh lens, L9 represents the eighth lens, L10 represents the filter, and L11 represents the imaging surface; the lenses L1 to L8 are arranged sequentially from the object side to the image side, the aperture stop L4 is located on the image side of the third lens L3 and the object side of the fourth lens L5, and the IR filter L10 is located between the eighth lens L9 and the imaging surface L11.

[0030] Figure 1 In the diagram, S1 represents the object-side surface of the first lens L1, S2 represents the image-side surface of the first lens L1; S3 represents the object-side surface of the second lens L2, S4 represents the image-side surface of the second lens L2, and also represents the object-side surface of the third lens L3 cemented with the second lens L2; ​​S5 represents the image-side surface of the third lens L3; S6 represents the surface of the aperture L4; S7 represents the object-side surface of the fourth lens L5, S8 represents the image-side surface of the fourth lens L5, and also represents the object-side surface of the fifth lens L6 cemented with the fourth lens L5. S9 represents the image-side surface of the fifth lens L6; S10 represents the object-side surface of the sixth lens L7, and S11 represents the image-side surface of the sixth lens L7; S12 represents the object-side surface of the seventh lens L8, and S13 represents the image-side surface of the seventh lens L8; S14 represents the object-side surface of the eighth lens L9, and S15 represents the image-side surface of the eighth lens L9; S16 represents the object-side surface of the filter L10 (such as an IR filter), and S17 represents the image-side surface of the filter L10; S18 represents the surface where the imaging surface L11 is located.

[0031] The optical parameters in the following embodiments of the present invention include: Fov Indicates the maximum field of view of the lens. Y m Indicates correspondence Fov The image is tall, Y 1 indicates the image height of the lens when the half-field angle is 1°. TTL This indicates the total length of the lens, which in this embodiment is the distance along the optical axis from the vertex of the object-side surface of the first lens to the imaging surface L11, 2× D 1 represents the effective diameter of the first lens. f 1 represents the focal length of the first lens. f 2 represents the focal length of the second lens. f 3 indicates the focal length of the third lens. f 4 represents the focal length of the fourth lens. f 5 indicates the focal length of the fifth lens. f 6 represents the focal length of the sixth lens. f 7 indicates the focal length of the seventh lens. f 8 represents the focal length of the eighth lens. fIndicates the entire focal length of the lens. bfl Indicates the rear focal length of the lens. pi Represents pi (π). r i1 Let represent the radius of curvature of the object-side surface of the i-th lens. r i2 Let be the radius of curvature of the image-side surface of the i-th lens, and vdi be the Abbe constant of the i-th lens. d Sm-Sn The distance between the optical axes of the surface with surface number Sm and the surface with surface number Sn (i, m, n are integers).

[0032] The lens in this embodiment is designed with a focal length of approximately 35mm, good uniformity of center and edge resolution across the entire field of view, and adequate OTF modulus and relative illumination, while also exhibiting low distortion and low image distortion.

[0033] From an economic and cost perspective, all lenses from the first lens L1 to the eighth lens L9 can be made of spherical lenses, significantly reducing mold costs and manufacturing complexity. The curvature radius and center thickness of key lenses can be precisely defined to optimize aberration contributions. This invention does not limit each lens to using only spherical lenses.

[0034] First embodiment: Tables 1, 2, 3, and 4 show a first numerical embodiment of the optical lens according to the present invention, in conjunction with... Figures 1 to 10 To understand the first embodiment, Figure 1 The lens arrangement of the lens is shown in the following figure: From the object side to the image side, the following lenses are sequentially arranged: first lens L1, second lens L2, third lens L3, fourth lens L5, fifth lens L6, sixth lens L7, seventh lens L8, and eighth lens L9. The concave / convex surface characteristics and optical power characteristics of each lens are as follows: The first lens L1 has positive optical power, its object side has a convex structure near the optical axis, and its image side has a concave structure near the optical axis. The second lens L2 is a biconvex lens with positive optical power, and the third lens L3 is a biconcave lens with negative optical power. The second lens L2 and the third lens L3 form a cemented lens, which makes the lens structure compact, reduces the number of light reflections between the lenses to reduce the loss of light energy, and lowers the misjudgment rate in the algorithm recognition process. In addition, the Abbe constant difference between the first lens and the second lens, and the Abbe constant difference between the second lens and the third lens are relatively large, which is beneficial to correct chromatic aberration, improve image quality, reduce assembly sensitivity, and increase image plane size. Therefore, the second lens L2, together with the first lens L1 and the third lens L3, forms an achromatic lens group. The fourth lens L5 is a biconcave mirror with negative optical power, and the fifth lens L6 is a biconvex mirror with positive optical power. The fourth lens L5 and the fifth lens L6 form a cemented lens. The Abbe constants of the fifth lens and the sixth lens are both relatively large. Therefore, the fourth lens, the fifth lens, and the sixth lens form an achromatic lens group. The sixth lens L7 is a biconvex lens with positive optical power, the seventh lens L8 is a biconcave lens with negative optical power, and the eighth lens L9 is a biconvex lens with positive optical power.

[0035] The above positive-positive-negative-negative-positive-positive-negative-positive optical power sequence, combined with a specific surface shape, is beneficial for better correction of off-axis aberrations, control of field curvature and distortion, and improvement of uniformity across the entire field of view.

[0036] In this embodiment, the optical lens satisfies: 20°≤ Fov ≤30°, 17.5mm≤ Y m ≤18.6mm, 12.2mm≤2× D 1≤16.2mm, 1.05mm≤ Y 1≤1.88mm, 45mm≤ TTL ≤60.5mm, 0.28≤ Y m / TTL ≤0.4, 31mm≤ f ≤38mm, 9.5mm≤ f 5≤11mm, 0.5° / mm≤ Fov / Y m / 2≤0.87° / mm, 1.2≤ TTL / f ≤1.75, 0.3≤2× D 1 / f ≤0.5, 65≤ Y 1×180 / pi ≤100, 0.75≤ f 1 / f ≤1.05, 0.6≤ f 2 / f ≤0.81, -0.38≤ f 3 / f ≤-0.22, -0.35≤ f 4 / f ≤-0.2, 0.2≤ f 5 / f ≤0.36, 1≤ f 6 / f ≤1.3, -0.88≤ f 7 / f ≤-0.68, 0.6≤ f 8 / f ≤0.78, 0.3≤ bfl / f ≤0.5, 0.32≤ bfl / TTL ≤0.5, 0.022° / mm 2 ≤ Fov / (2× D 1) / TTL ≤0.043° / mm 2 ,7≤ r 12 / r 11 ≤8, 13≤ r 21 ≤13.8, 9.2≤ r 32 ≤10.3, -0.78≤ r 41 / r 42 ≤-0.7, 14.6mm≤ r 42 ≤18.5mm, 14.6≤ r 51 ≤18.5, -18≤ r 52 ≤-15.5, 33≤ r 81 ≤38, -50≤ r 82 ≤-46; The optical axis distance from the object side surface of the first lens L1 to the image side surface of the third lens L3 d S1-S5 The sum of the air gaps between the optical axes of the first and third lenses is between 0.1 mm and 1 mm, ranging from 11.6 mm to 12.6 mm; the center thickness of the first lens L1 is between 0.1 mm and 1 mm. d S1-S2 The center thickness of the second lens L2 is between 4.5mm and 5.25mm. d S3-S4 The center thickness of the third lens L3 is between 2.1mm and 2.95mm. d S4-S5 Between 4mm and 4.8mm; the center thickness of the sixth lens L7 d S10-S11 The center thickness of the seventh lens L8 is between 1.4mm and 1.6mm. d S12-S13 The center thickness of the eighth lens L9 is between 2.1 mm and 2.5 mm, ranging from 0.7 mm to 0.9 mm; the optical axis distance from the object-side surface of the fourth lens L5 to the image-side surface of the eighth lens L9 is... d S7-S15Between 8mm and 8.6mm; the optical axis distance from the object-side surface of the seventh lens L8 to the image-side surface of the eighth lens L9. d S12-S15 Between 3mm and 3.8mm; the optical axis distance from the image-side surface of the eighth lens L9 to the imaging surface IMA. d S15-S18 Between 19.9mm and 22mm.

[0037] As described above, the second lens L2 and the third lens L3 constitute a cemented lens, 2.1≤ -f 2 / f 3≤2.44, 50≤vd2-vd1≤60, 50≤vd2-vd3≤60, where vd1 is the Abbe constant of the first lens, vd2 is the Abbe constant of the second lens, and vd3 is the Abbe constant of the third lens; The fourth lens L5 and the fifth lens L6 form a cemented lens, 0.86≤ -f 4 / f 5≤1.06, 20≤vd5-vd6≤28, where vd6 is the Abbe constant of the sixth lens and vd5 is the Abbe constant of the fifth lens.

[0038] In a specific numerical embodiment, the optical parameters of each lens, aperture, and IR filter are shown in Tables 1 to 4: Table 1 Lens optical parameters of the first embodiment

[0039] In the table, a surface with an infinite radius of curvature indicates that its corresponding surface number represents a plane.

[0040] Among them, the interval distance D_1 between the image side of the sixth lens L7 (surface number S11) and the object side of the seventh lens L8, and the interval distance D_2 between the image side of the filter L10 (surface number S17) and the imaging surface are variable distances. The variable interval distance D_1 has a variable range of 0.45mm to 12.5mm, and the variable interval distance D_2 has a variable range of 0.8mm to 1.2mm.

[0041] Taking object distances of 250mm, 2000mm, and 150mm as examples, the corresponding interval distances D_1 and D_2 are shown in Table 2: Table 2. Variable interval distances corresponding to the three object distances in the first embodiment.

[0042] At an object distance of 250mm, the lens magnification is 0.1576; at an object distance of 2000mm, the lens magnification is 0.0175; and at an object distance of 150mm, the lens magnification is 0.2898.

[0043] Other optical parameters of the lens in this embodiment are shown in Table 3: Table 3 Other optical parameters of the lens at three object distances in the first embodiment

[0044] The optical parameter expressions of the lens in this embodiment are shown in Table 4: Table 4. Optical parameter expressions for the lens at three object distances in the first embodiment.

[0045] The table data in this embodiment uses rounding to obtain the calculated values.

[0046] This embodiment optimizes the maximum field of view of the lens through collaborative optimization. Fov Like Gao Y 1. Full field of view image height Y m Back focal length bfl Parameters constrain edge aberrations and image plane matching; simultaneously, the focal lengths of the first to eighth lenses are specifically assigned. f 1- f 8. By finely adjusting the curvature radius of each lens surface and the air gap between lenses, astigmatism, field curvature and distortion are evenly distributed across the entire field of view, thereby significantly improving the uniformity of imaging across the entire field of view.

[0047] The optical power arrangement ends in a negative-positive sequence, with longer sequences... bfl This allows for sufficient working distance to the last positive lens, enabling it to more smoothly correct field curvature and distortion, avoiding edge quality degradation caused by forcibly compressing the overall length. Longer... bfl It also helps light reach the sensor edge at a smaller angle of incidence, which is beneficial for large sensors (such as 1.1 inches and above) to prevent edge vignetting (Cos4 attenuation) and color shift (CRA matching). Maintaining TTL / f Under the premise of a compact overall length not exceeding 1.9, combined with a longer... bfl, It provides ample installation space for the filter components, and at the same time, it utilizes this space to optimize the incident angle of the rear light group, effectively improving the relative illumination and astigmatism of the edge field of view.

[0048] In this embodiment, the positive lens with the highest optical power is the fifth lens (9.5mm≤). f (6≤10.5mm), placing it in the middle to rear position and cementing it with the fourth lens not only enhances the converging ability to compress the length, but also facilitates centralized correction of advanced aberrations and constrains marginal aberrations and image plane matching. The negative lens with the highest optical power is the third or fourth lens (-13mm≤ f3≤-5.5mm, -13.3mm≤ f (4≤-9mm), placing it close to the positive lens with the highest optical power can make the positive and negative strong lenses contribute opposite signs to the Petzval field curvature. Since the distance between the positive and negative strong lenses is small, the position of the principal plane has little influence, which makes it easy to cancel the Petzval term, thus making the image plane flatter, and the edges and center focus on the same image plane, achieving uniform MTF across the entire field of view.

[0049] The compact lens design in this embodiment can be integrated with an electronic image sensor to form a camera device (line scan camera or area scan camera) for use in industrial inspection equipment (such as automated optical inspection equipment).

[0050] Based on a lens resolution of 100LP / mm, Figures 2 to 4 The images show the MTF (Modulation Transfer Function) frequency curves of the lens in the first embodiment above at object distances of 250mm, 2000mm, and 150mm. The horizontal axis represents spatial frequency in line pairs per millimeter (LP / mm), and the vertical axis represents OTF modulus (a dimensionless normalized value). Figure 2 It can be seen that, in millimeters, TS 0.0000 (mm) represents an OTF modulus of approximately 62% for the central field of view, while TS 8.1450 (mm) represents an OTF modulus of approximately 52% for the near-edge field of view (0.9 field of view). Figure 3 It can be seen that, in millimeters, TS 0.0000 (mm) represents an OTF modulus of approximately 68% for the central field of view, while TS 8.1450 (mm) represents an OTF modulus of approximately 64% for the near-edge field of view (0.9 field of view). In millimeters, from... Figure 4 As can be seen, in millimeters, TS 0.0000 (mm) represents an OTF modulus of approximately 52% in the center field of view, and TS 9.0500 (mm) represents an OTF modulus of approximately 52% in the edge field of view, indicating that the lens can produce clear images. At different object distances, the lens exhibits excellent and balanced performance in both the center and edge field of view OTF modulus. The absolute difference between the edge and center field of view is controlled within 10%, and the relative attenuation is controlled within 20%, meeting the design requirement of highly consistent performance across the entire field of view.

[0051] Figures 5 to 7 The images show the relative illumination curves of the lens in the first embodiment described above at object distances of 250mm, 2000mm, and 150mm. The relative illumination diagram reflects the uniformity of illumination in the image. The horizontal axis represents the Y-field of view in millimeters (mm), and the vertical axis represents the relative illumination (a dimensionless, normalized value). Figure 5It can be seen that the optical lens in this specific embodiment has a relative illumination of approximately 85% corresponding to a Y-field of view of approximately 9.05mm, reflecting that the lens has high relative illumination and sufficient light intake. From Figure 6 It can be seen that the relative illumination corresponding to a Y-field of view of approximately 9.05mm is about 72%, reflecting that the lens has high relative illumination and sufficient light intake. From Figure 7 As can be seen, the relative illumination corresponding to a Y field of view of approximately 9.05mm is about 92%, reflecting that the lens has a high relative illumination and sufficient light intake, ensuring that even when the lens is used in relatively dark environments, there will be no vignetting at the edges of the actual image.

[0052] Figures 8 to 10 The images show the distortion of the lens in the first embodiment above at object distances of 250mm, 2000mm, and 150mm. Distortion is a principal ray aberration, reflecting the similarity of the image. The horizontal axis represents the distortion percentage (in %), and the vertical axis represents the normalized image height (dimensionless). Figure 8 The maximum distortion is approximately 0.04%. Figure 9 The maximum distortion is approximately -0.05%. Figure 10 The maximum distortion is about 0.23%, which means that the distortion of the optical lens in this embodiment is well controlled, the lens image has no obvious distortion, and the image distortion is low.

[0053] Second embodiment: Tables 5, 6, 7, and 8 show a second numerical embodiment of the optical lens according to the present invention, in conjunction with... Figures 11 to 20 To understand the second embodiment, the lens arrangement of the lens is as follows: Figure 11 As shown, compared with the first embodiment, the positive and negative optical power characteristics of the lens remain unchanged. The difference in lens surface shape is that the object side S1 of the first lens L1 in the second embodiment is concave and its image side S2 is convex; the object side S12 of the seventh lens L8 is convex.

[0054] In this embodiment, the optical lens satisfies: 22°≤ Fov ≤32.9°, 17.6mm≤ Y m ≤18.5mm, 10mm≤2× D 1≤13.7mm, 1.05mm≤ Y 1≤1.5mm, 46mm≤ TTL ≤61mm, 0.28≤ Y m / TTL ≤0.38, 31mm≤ f ≤36mm, 10mm≤ f 5≤11.5mm, 1.11° / mm≤ Fov / Y m / 2≤1.45° / mm,1.4≤ TTL / f ≤1.9,0.28≤2× D 1 / f ≤0.44,60≤ Y 1×180 / pi ≤85,1.5≤ f 1 / f ≤1.68,0.3≤ f 2 / f ≤0.4,-0.28≤ f 3 / f ≤-0.15,-0.35≤ f 4 / f ≤-0.28,0.26≤ f 5 / f ≤0.38,1.65≤ f 6 / f ≤1.88,-1.9≤ f 7 / f ≤-1.8,1.22≤ f 8 / f ≤1.3,0.7≤ bfl / f ≤1.1,0.47≤ bfl / TTL ≤0.6,0.035° / mm 2 ≤ Fov / (2× D 1) / TTL ≤0.052° / mm 2 ,7.3≤ r 11 / r 12 ≤8.3,11.5≤ r 21 ≤13,9.2≤ r 32 ≤10.3,-0.78≤ r 41 / r 42 ≤-0.7,15.2mm≤ r 42 ≤16.5mm,15.2≤ r 51 ≤16.5,-20≤ r 52 ≤-18.6,44≤ r 81 ≤52,-53≤ r 82 ≤-47.5; The optical axis distance from the object side surface of the first lens L1 to the image side surface of the third lens L3 d S1-S5 The sum of the air gaps between the optical axes of the first and third lenses is between 0.05 mm and 0.5 mm, ranging from 6 mm to 8 mm; the center thickness of the first lens L1 is between 0.05 mm and 0.5 mm. d S1-S2 The center thickness of the second lens L2 is between 1.1mm and 1.5mm. d S3-S4 The center thickness of the third lens L3 is between 4.3mm and 5.1mm. d S4-S5 The center thickness of the sixth lens L7 is between 0.7 mm and 0.95 mm. d S10-S11 The center thickness of the seventh lens L8 is between 1.5mm and 1.69mm. d S12-S13 The center thickness of the eighth lens L9 is between 1.9 mm and 2.25 mm, ranging from 0.7 mm to 0.9 mm; the optical axis distance from the object-side surface of the fourth lens L5 to the image-side surface of the eighth lens L9 is... d S7-S15 Between 14mm and 14.8mm; the optical axis distance from the object-side surface of the seventh lens L8 to the image-side surface of the eighth lens L9. d S12-S15 Between 3mm and 3.8mm; the optical axis distance from the image-side surface of the eighth lens L9 to the imaging surface IMA. d S15-S18 Between 24mm and 33mm.

[0055] As described above, the second lens L2 and the third lens L3 constitute a cemented lens, 1.5≤ -f 2 / f 3≤1.84; The fourth lens L5 and the fifth lens L6 form a cemented lens, 0.9≤ -f 4 / f 5≤1.1, 30≤vd6-vd5≤38, where vd6 is the Abbe constant of the sixth lens and vd5 is the Abbe constant of the fifth lens.

[0056] In a specific numerical embodiment, the optical parameters of each lens, aperture, and IR filter are shown in Tables 5 to 8: Table 5 Lens optical parameters of the second embodiment

[0057] In the table, if the radius of curvature is infinite, it means that the corresponding surface number represents a plane.

[0058] Among them, the interval distance D_1 between the image side of the sixth lens L7 (surface number S11) and the object side of the seventh lens L8, and the interval distance D_2 between the image side of the filter L10 (surface number S17) and the imaging surface are variable distances. The variable interval distance D_1 has a variable range of 0.2 mm to 2.9 mm, and the variable interval distance D_2 has a variable range of 6 mm to 13 mm.

[0059] Taking object distances of 250mm, 2000mm, and 150mm as examples, the corresponding interval distances D_1 and D_2 are shown in Table 6: Table 6. Variable Interval Distances Corresponding to the Three Object Distances in the Second Embodiment

[0060] At an object distance of 250mm, the lens magnification is 0.1422; at an object distance of 2000mm, the lens magnification is 0.0165; and at an object distance of 150mm, the lens magnification is 0.2516.

[0061] Other optical parameters of the lens in this embodiment are shown in Table 7: Table 7 Other optical parameters of the lens at three object distances in the second embodiment

[0062] The optical parameter expressions of the lens in this embodiment are shown in Table 8: Table 8. Optical parameter expressions for the lens at three object distances in the second embodiment.

[0063] The table data in this embodiment uses rounding to obtain the calculated values.

[0064] Based on a lens resolution of 100LP / mm, Figures 12 to 14 The images show the MTF (Modulation Transfer Function) frequency curves of the lens in the second embodiment above at object distances of 250mm, 2000mm, and 150mm. The horizontal axis represents spatial frequency in line pairs per millimeter (LP / mm), and the vertical axis represents OTF modulus (a dimensionless normalized value). Figure 12 It can be seen that, in millimeters, TS 0.0000 (mm) represents an OTF modulus of approximately 63% for the central field of view, while TS 8.1450 (mm) represents an OTF modulus of approximately 55% for the near-edge field of view (0.9 field of view). Figure 13It can be seen that, in millimeters, TS 0.0000 (mm) represents an OTF modulus of approximately 68% for the central field of view, while TS 8.1450 (mm) represents an OTF modulus of approximately 59% for the near-edge field of view (0.9 field of view). Figure 14 As can be seen, in millimeters, TS 0.0000 (mm) represents a central field-of-view OTF modulus of approximately 58%, while TS 9.0500 (mm) represents a peripheral field-of-view OTF modulus of approximately 48%, indicating that the lens can produce clear images. At different object distances, the absolute difference between the peripheral field-of-view OTF modulus and the central field-of-view OTF modulus is controlled within 10%, and the relative attenuation is controlled within 20%, meeting the design requirement of highly consistent performance across the entire field of view.

[0065] Figures 15 to 17 The images above show the relative illumination curves of the lens in the second embodiment for object distances of 250mm, 2000mm, and 150mm. The relative illumination diagram reflects the uniformity of illumination in the image. The horizontal axis represents the Y-field of view in millimeters (mm), and the vertical axis represents the relative illumination (dimensionless, normalized value). Figure 15 It can be seen that the optical lens in this specific embodiment has a relative illumination of approximately 95% corresponding to a Y-field of view of approximately 9.05mm, reflecting that the lens has high relative illumination and sufficient light intake. From Figure 16 As can be seen, the relative illumination corresponding to a Y-field of view of approximately 9.05mm is approximately 88%, reflecting that this lens has high relative illumination and sufficient light intake. From Figure 17 As can be seen, the relative illumination corresponding to a Y field of view of approximately 9.05mm is approximately 95%, reflecting that the lens has a high relative illumination and sufficient light intake, ensuring that even when the lens is used in relatively dark environments, there will be no vignetting at the edges of the actual image.

[0066] Figures 18 to 20 The images show the distortion of the lens in the second embodiment above at object distances of 250mm, 2000mm, and 150mm. Distortion is a principal ray aberration, reflecting the similarity of the image. The horizontal axis represents the distortion percentage (in %), and the vertical axis represents the normalized image height (dimensionless). Figure 18 The maximum distortion is approximately -1%. Figure 19 The maximum distortion is approximately -1.3%. Figure 20 The maximum distortion is approximately -0.8%, meaning that the optical lens in this embodiment has low distortion, no obvious distortion in the lens image, and low image distortion.

[0067] Third embodiment: Tables 9, 10, 11, and 12 show a third numerical embodiment of the optical lens according to the present invention, in conjunction with... Figures 21 to 30To understand the third embodiment, the lens arrangement of the lens is as follows: Figure 21 As shown, compared with the first embodiment, the positive and negative optical power characteristics of the lens remain unchanged. The differences in lens surface shape are that the image side surface S4 (i.e., the cemented surface of the second lens and the third lens) of the second lens L2 in the third embodiment is concave, the object side surface S10 of the sixth lens L7 is concave, and the object side surface S12 of the seventh lens L8 is flat.

[0068] The Abbe constants of the first to the third lenses are low, high, and low, respectively. The difference in the Abbe constant values ​​of adjacent lenses is greater than 40. Therefore, the second lens L2, together with the first lens L1 and the third lens L3, forms an achromatic lens group.

[0069] In this embodiment, the optical lens satisfies: 20°≤ Fov ≤30°, 17.8mm≤ Y m ≤18.4mm, 13mm≤2× D 1≤17.8mm, 1.1mm≤ Y 1≤1.8mm, 48mm≤ TTL ≤62mm, 0.28≤ Y m / TTL ≤0.38, 35mm≤ f ≤38mm, 15mm≤ f 5≤16.2mm, 0.6° / mm≤ Fov / Y m / 2≤0.9° / mm, 1.2≤ TTL / f ≤1.75, 0.3≤2× D 1 / f ≤0.55, 67≤ Y 1×180 / pi ≤96, 0.85≤ f 1 / f ≤1.1, 0.62≤ f 2 / f ≤0.78, -0.36≤ f 3 / f ≤-0.29, -0.39≤ f 4 / f ≤-0.28, 0.4≤ f 5 / f ≤0.48, 0.75≤ f 6 / f ≤0.89, -1.1≤ f 7 / f ≤-0.88, 0.65≤ f 8 / f≤0.8, 0.55≤ bfl / f ≤0.94, 0.4≤ bfl / TTL ≤0.55, 0.022° / mm 2 ≤ Fov / (2× D 1) / TTL ≤0.038° / mm 2 ,4≤ r 12 / r 11 ≤5, 13≤ r 21 ≤14, 9.2≤ r 32 ≤10.1, -0.86≤ r 41 / r 42 ≤-0.65, 15.8mm≤ r 42 ≤17.8mm, 15.8≤ r 51 ≤17.8, -34≤ r 52 ≤-30, 24≤ r 81 ≤28, -40≤ r 82 ≤-36; The optical axis distance from the object side surface of the first lens L1 to the image side surface of the third lens L3 d S1-S5 The sum of the air gaps between the optical axes of the first and third lenses is between 0.05 mm and 0.5 mm, ranging from 8 mm to 9.3 mm; the center thickness of the first lens L1 is between 8 mm and 9.3 mm. d S1-S2 The center thickness of the second lens L2 is between 1.8mm and 2.15mm. d S3-S4 The center thickness of the third lens L3 is between 2mm and 2.65mm. d S4-S5 Between 3.9mm and 4.75mm; the center thickness of the sixth lens L7 d S10-S11 The center thickness of the seventh lens L8 is between 1.4mm and 1.64mm. d S12-S13 The center thickness of the eighth lens L9 is between 2.5 mm and 3.2 mm, ranging from 0.7 mm to 0.9 mm; the optical axis distance from the object-side surface of the fourth lens L5 to the image-side surface of the eighth lens L9 is... d S7-S15Between 9.6mm and 11.6mm; the optical axis distance from the object-side surface of the seventh lens L8 to the image-side surface of the eighth lens L9. d S12-S15 Between 5mm and 6.8mm; the optical axis distance from the image-side surface of the eighth lens L9 to the imaging surface IMA. d S15-S18 Between 20mm and 32mm.

[0070] As described above, the second lens L2 and the third lens L3 constitute a cemented lens, 1.8≤ -f 2 / f 3≤2.45, 38≤vd2-vd1≤48, 37≤vd2-vd3≤44, where vd1 is the Abbe constant of the first lens, vd2 is the Abbe constant of the second lens, and vd3 is the Abbe constant of the third lens; The fourth lens L5 and the fifth lens L6 form a cemented lens, 0.7≤ -f 4 / f 5≤0.88, 18≤vd5-vd6≤20, where vd6 is the Abbe constant of the sixth lens and vd5 is the Abbe constant of the fifth lens.

[0071] In a specific numerical embodiment, the optical parameters of each lens, aperture, and IR filter are shown in Tables 9 to 12: Table 9 Lens optical parameters of the third embodiment

[0072] In the table, if the radius of curvature is infinite, it means that the corresponding surface number represents a plane.

[0073] Among them, the interval distance D_1 between the image side of the sixth lens L7 (surface number S11) and the object side of the seventh lens L8, and the interval distance D_2 between the image side of the filter L10 (surface number S17) and the imaging surface are variable distances. The variable interval distance D_1 has a variable range of 0.2 mm to 4 mm, and the variable interval distance D_2 has a variable range of 2 mm to 12 mm.

[0074] Taking object distances of 250mm, 2000mm, and 150mm as examples, the corresponding interval distances D_1 and D_2 are shown in Table 10: Table 10 Variable Interval Distance Table Corresponding to Three Object Distances in the Third Embodiment

[0075] At an object distance of 250mm, the lens magnification is 0.1552; at an object distance of 2000mm, the lens magnification is 0.0179; and at an object distance of 150mm, the lens magnification is 0.2758.

[0076] Other optical parameters of the lens in this embodiment are shown in Table 11: Table 11 Other optical parameters of the lens at three object distances in the third embodiment

[0077] The optical parameter expressions of the lens in this embodiment are shown in Table 12: Table 12 Optical parameter expressions for the lens at three object distances in the third embodiment

[0078] The table data in this embodiment uses rounding to obtain the calculated values.

[0079] Based on a lens resolution of 100LP / mm, Figures 22 to 24 The images show the MTF (Modulation Transfer Function) frequency curves of the lens in the third embodiment above at object distances of 250mm, 2000mm, and 150mm. The horizontal axis represents spatial frequency in line pairs per millimeter (LP / mm), and the vertical axis represents OTF modulus (a dimensionless normalized value). Figure 22 It can be seen that, in millimeters, the OTF modulus of the central field of view represented by TS 0.0000 (mm) is approximately 62%, while the OTF modulus of the peripheral field of view represented by TS 9.0500 (mm) is approximately 60%. From... Figure 23 It can be seen that, in millimeters, the OTF modulus of the central field of view represented by TS0.0000 (mm) is approximately 65%, while the OTF modulus of the near-edge field of view (0.9 field of view) represented by TS 8.1450 (mm) is approximately 64%. Figure 24 It can be seen that TS 0.0000 (mm) represents an OTF modulus of approximately 53% for the center field of view, and TS 9.0500 (mm) represents an OTF modulus of approximately 56% for the edge field of view, indicating that the lens can produce clear images. At different object distances, the absolute difference between the OTF modulus of the edge field of view and the OTF modulus of the center field of view is controlled within 5%, and the relative attenuation is controlled within 10%, meeting the design requirement of highly consistent performance across the entire field of view.

[0080] Figures 25 to 27 The images above show the relative illumination curves of the lens in the third embodiment at object distances of 250mm, 2000mm, and 150mm. The relative illumination diagram reflects the uniformity of illumination in the image. The horizontal axis represents the Y-field of view in millimeters (mm), and the vertical axis represents the relative illumination (dimensionless, normalized value). Figure 25As can be seen, the optical lens in this specific embodiment has a relative illumination of approximately 94% corresponding to a Y-field of view of approximately 9.05mm, reflecting that the lens has high relative illumination and sufficient light intake. From Figure 26 It can be seen that the relative illumination corresponding to a Y-field of view of approximately 9.05mm is approximately 90%, reflecting that this lens has high relative illumination and sufficient light intake. From Figure 27 As can be seen, the relative illumination corresponding to a Y field of view of approximately 9.05mm is approximately 96%, reflecting that the lens has a high relative illumination and sufficient light intake, ensuring that even when the lens is used in relatively dark environments, there will be no vignetting at the edges of the actual image.

[0081] Figures 28 to 30 The images show the distortion of the lens in the third embodiment above at object distances of 250mm, 2000mm, and 150mm. Distortion is a principal ray aberration, reflecting the similarity of the image. The horizontal axis represents the distortion percentage (in %), and the vertical axis represents the normalized image height (dimensionless). Figure 28 The maximum distortion is approximately -1%. Figure 29 The maximum distortion is approximately -1%. Figure 30 The maximum distortion is approximately -0.92%, meaning that the optical lens in this embodiment has low distortion and low image distortion.

[0082] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0083] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. An optical lens comprising eight lenses of optical power, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially along the optical axis from the object plane to the image plane, characterized in that: The object-side surface of the first lens has a convex structure near the optical axis, and the image-side surface has a concave structure near the optical axis. The ratio of the larger of the absolute value of the radius of curvature of the object-side surface and the absolute value of the radius of curvature of the image-side surface to the smaller of the smaller value is between 7 and 8. The center thickness of the first lens is between 4.5 mm and 5.25 mm. The second, fifth, sixth, and eighth lenses are biconvex mirrors; the third, fourth, and seventh lenses are biconcave mirrors. The optical powers of the first to the eighth lenses are positive, positive, negative, negative, positive, positive, negative, positive, respectively; The sum of the air gaps between the optical axes of the first lens and the eighth lens is between 5.5 mm and 18.6 mm; The optical lens satisfies: 34.71mm ≤ f ≤38mm, 12.5mm≤2× D 1≤15.6mm, 10≤ Y m / Y 1≤16.5, where, f For the entire focal length of the lens, 2× D 1 is the effective diameter of the first lens. Y m The image height corresponding to the maximum field of view. Y 1 represents the lens image height when the half-field angle is 1°; The focal length of each lens satisfies the following condition: 0.75 ≤ f 1 / f ≤1.05, 0.6≤ f 2 / f ≤0.81, -0.38≤ f 3 / f ≤-0.22, -0.35≤ f 4 / f ≤-0.2, 0.2≤ f 5 / f ≤0.36, 1≤ f 6 / f ≤1.3, -0.88≤ f 7 / f ≤-0.68, 0.6≤ f 8 / f ≤0.78, where, f 1 is the focal length of the first lens ，f 2 represents the focal length of the second lens. f 3 is the focal length of the third lens ，f 4 represents the focal length of the fourth lens. f 5 is the focal length of the fifth lens. f 6 represents the focal length of the sixth lens. f 7 is the focal length of the seventh lens. f 8 represents the focal length of the eighth lens; Among the eight lenses with optical power, the positive lens with the highest optical power is the fifth lens, whose focal length is between 9.5mm and 10.5mm; the object side radius of curvature of the fifth lens is between 14.6mm and 18.5mm, and the image side radius of curvature is between -18mm and -15.5mm.

2. The optical lens according to claim 1, characterized in that, The optical lens satisfies: 20°≤ Fov ≤34°, 45mm≤ TTL ≤62mm, where, Fov The maximum field of view of the lens. TTL It is the distance on the optical axis from the vertex of the object side of the first lens to the imaging surface.

3. The optical lens according to claim 1, characterized in that, The radius of curvature of the object-side surface of the second lens is between 11.5 mm and 14 mm; The radius of curvature of the image-side surface of the third lens is between 9.2 mm and 10.3 mm; The ratio of the object-side radius of curvature of the fourth lens to the image-side radius of curvature is between -0.86 and -0.

65. The object-side radius of curvature of the fifth lens is between 14.5 mm and 18.8 mm, and the image-side radius of curvature is between -34 mm and -15.5 mm. The object-side radius of curvature of the eighth lens is between 24 mm and 52 mm, and the image-side radius of curvature is between -53 mm and -36 mm.

4. The optical lens according to claim 1, characterized in that, The optical axis distance from the object side of the first lens to the image side of the third lens is between 6 mm and 12.6 mm, and the sum of the air gaps between the optical axes of the first lens and the third lens is between 0.05 mm and 1 mm. And / or, the center thickness of the second lens is between 2 mm and 5.15 mm, and the center thickness of the third lens is between 0.7 mm and 4.8 mm.

5. The optical lens according to claim 4, characterized in that, The optical axis distance from the object side of the fourth lens to the image side of the eighth lens is between 8 mm and 14.8 mm; The optical axis distance from the object side of the seventh lens to the image side of the eighth lens is between 3 mm and 6.8 mm. The optical axis distance from the image side surface to the imaging surface of the eighth lens is between 19.9 mm and 33 mm; The optical lens satisfies: 19.9≤ bfl ≤33.6, 0.3≤ bfl / f ≤1.1, 0.3≤ bfl / TTL ≤0.6, 1.2≤ TTL / f ≤1.9, where, bfl The rear focal length of the lens. TTL It is the distance on the optical axis from the vertex of the object side of the first lens to the imaging surface.

6. The optical lens according to claim 1, characterized in that, Among the eight lenses with optical power, the lens with the smallest center thickness is the seventh lens; The center thickness of the sixth lens is between 1.4 mm and 1.7 mm, the center thickness of the seventh lens is between 0.7 mm and 0.9 mm, and the center thickness of the eighth lens is between 1.9 mm and 3.2 mm.

7. The optical lens according to claim 1, characterized in that, The optical lens satisfies: 0.02≤ Fov / (2× D 1) / TTL ≤0.052, 0.5≤ Fov / Y m / 2≤1.45, and 0.28≤ Y m / TTL ≤0.4, 1.2≤ TTL / f ≤1.9, where, Fov The maximum field of view of the lens. TTL It is the distance on the optical axis from the vertex of the object side of the first lens to the imaging surface.

8. The optical lens according to claim 1, characterized in that, The second lens and the third lens constitute a cemented lens, and the optical lens satisfies: 1.5 ≤ -f 2 / f 3≤2.44, 35≤vd2-vd1≤60, 35≤vd2-vd3≤60, where, f 2 represents the focal length of the second lens. f 3 is the focal length of the third lens, vd1 is the Abbe constant of the first lens, vd2 is the Abbe constant of the second lens, and vd3 is the Abbe constant of the third lens.

9. The optical lens according to claim 1, characterized in that, The fourth and fifth lenses form a cemented lens, and the optical lens satisfies: 14.6mm ≤ r 42 ≤18.5mm, 0.7≤ -f 4 / f 5≤1.1, 18≤|vd6-vd5|≤38, where, r 42 Let be the radius of curvature of the image-side surface of the fourth lens. f 4 represents the focal length of the fourth lens. f 5 is the focal length of the fifth lens, vd6 is the Abbe constant of the sixth lens, and vd5 is the Abbe constant of the fifth lens.

10. The optical lens according to claim 1, characterized in that, Among the eight lenses with optical power, the negative lens with the highest optical power is the third or fourth lens, with a focal length between -13mm and -5.5mm.

11. The optical lens according to claim 1, characterized in that, The refractive index of the eight-element lens with optical power ranges from 1.35 to 2.16, with the difference between the maximum and minimum refractive index ranging from 0.4 to 0.

52.

12. The optical lens according to claim 1, characterized in that, All eight lenses with optical power are spherical mirrors.

13. The optical lens according to claim 1, characterized in that, The optical axis distance between the image side of the sixth lens and the object side of the seventh lens is adjustable within the range of 0.2 mm to 12.5 mm.

14. The optical lens according to claim 1, characterized in that, The optical lens also includes a filter disposed between the eighth lens and the imaging surface, and the optical axis distance between the filter and the imaging surface is adjustable in the range of 0.8 mm to 13 mm.

15. The optical lens according to any one of claims 1 to 14, characterized in that, The lens satisfies: 60≤ Y 1×180 / pi ≤100； And / or, 0.28≤2× D 1 / f ≤0.55; And / or, 17.5mm≤ Y m ≤18.6mm; And / or, 1.05mm≤ Y 1≤1.88mm.

16. A camera device, characterized in that, It includes electronic photosensitive elements and optical lenses as described in any one of claims 1 to 15.

17. An industrial testing device, characterized in that, Includes an image processor and a camera device as described in claim 16.

Images