wide-angle lens

Abstract

This invention discloses a wide-angle lens, relating to the field of optical imaging technology, aiming to solve the problems of low relative illumination, high cost, and poor imaging effect of existing wide-angle lenses. The lens includes seven spherical glass lenses arranged sequentially along the optical axis and an aperture stop, with the aperture stop located between the fourth and fifth lenses. The optical power of the lenses is distributed in a "negative-negative-negative-positive-positive-negative-positive" sequence, and the fifth and sixth lenses are cemented together. The refractive index of the first, second, fourth, and sixth lenses is >1.9 and the Abbe number is <30, satisfying key parameters such as a field of view >150° and relative illumination >94%. This invention achieves an ultra-wide field of view, ultra-high illumination, and high resolution while reducing processing and assembly costs and improving mass production capabilities. It also corrects chromatic aberration and aberrations, has a stable structure, and is suitable for applications such as vehicle imaging and security monitoring.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to a wide-angle lens. Background Technology

[0002] In the field of optical imaging technology, wide-angle lenses are widely used in various devices such as mobile terminals, security monitoring, and vehicle imaging because they can capture a wider range of scene information in a limited space. Especially in the fields of security monitoring, consumers are constantly increasing their demands for wide field of view coverage, uniformity of image brightness, image clarity, and cost-effectiveness.

[0003] However, existing wide-angle lenses face several pressing problems in practical applications: First, to achieve a wide-angle effect, the relative illumination of existing wide-angle lenses is generally low, typically not exceeding 75%. Some related patents (such as patent number CN105974561B) disclose solutions where the relative illumination within the maximum image circle can only reach slightly above 60%, resulting in noticeable vignetting in the image and severely impacting visual perception. Furthermore, the signal-to-noise ratio in the edge region deteriorates sharply in low-light environments, hindering their application in high-end machine vision. Second, to correct the effects of wide-angle lenses… Aberrations: Many existing solutions rely on a large number of aspherical lenses, which not only significantly increases the difficulty of lens processing and production costs, but also reduces the pass rate of mass production; Third, some lens structures are poorly designed, with high sensitivity to lens assembly tolerances, resulting in low lens assembly stability and production yield, as well as poor image plane flatness and obvious field curvature, which further affects image quality; Fourth, some existing lenses are not optimized in terms of focal length ratio and the ratio of optical back focal length to total lens length, making it difficult to efficiently match with the imaging chip, resulting in light loss and failing to meet the requirements for high brightness uniformity. Summary of the Invention

[0004] To address the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a wide-angle lens that can achieve an ultra-wide field of view while ensuring high relative illumination; to reduce production costs and assembly difficulty by using spherical lenses, and to achieve better image clarity through reasonable optical power allocation.

[0005] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is as follows: a wide-angle lens is provided, including a lens assembly and an aperture stop. The lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object end to the image end along the optical axis. The first lens has negative optical power, with its object-side surface being convex and its image-side surface being concave; the second lens has negative optical power, with its object-side surface being convex and its image-side surface being concave; the third lens has negative optical power, with its image-side surface being concave; the fourth lens has positive optical power, with its object-side surface being convex; the fifth lens has positive optical power, with its object-side surface being convex and its image-side surface being convex; the sixth lens has negative optical power, with its object-side surface being concave and its image-side surface being convex, and the sixth lens is cemented with the fifth lens; the seventh lens has positive optical power, with its object-side surface being convex and its image-side surface being convex, and the aperture stop is located between the fourth lens and the fifth lens.

[0006] Furthermore, the field of view (FOV) of the wide-angle lens is greater than 150°, and the relative illumination of the wide-angle lens is greater than 94%.

[0007] Furthermore, the effective focal length f of the wide-angle lens and the effective focal length f4 of the fourth lens satisfy 2.4 < f4 / f < 2.7.

[0008] Furthermore, the maximum image circle IH on the imaging plane of the wide-angle lens and the total lens length TTL satisfy 0.285 < IH / TTL < 0.31.

[0009] Furthermore, the effective focal lengths f1 of the first lens, f2 of the second lens, and f3 of the third lens of the wide-angle lens satisfy 0.2 < f3 / (f1+f2) < 0.25.

[0010] Furthermore, the optical back focal length (BFL) of the wide-angle lens and the total lens length (TTL) satisfy BFL / TTL > 0.21.

[0011] Furthermore, the maximum distortion value DIMX of the wide-angle lens satisfies 62% < DIMX < 65%.

[0012] Furthermore, the ratio of the effective focal length f to the aperture size FNO of a wide-angle lens is the entrance pupil diameter, and the entrance pupil diameter of a wide-angle lens satisfies 0.9 < f / FNO < 1.1.

[0013] Furthermore, the refractive indices of the first lens, the second lens, the fourth lens, and the sixth lens are all greater than 1.90, and the Abbe numbers of the first lens, the second lens, the fourth lens, and the sixth lens are all less than 30.

[0014] Furthermore, the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, and seventh lens can all be made of spherical glass.

[0015] The wide-angle lens of this invention has at least the following beneficial effects: Addressing the technical problems of existing wide-angle lenses, such as low relative illumination (typically not exceeding 75%), high cost and low mass production yield due to reliance on aspherical lenses, insufficient aberration correction, sensitivity to assembly tolerances and poor assembly stability, and insufficient optimization of focal length ratio and the ratio of back focal length to total length, this invention achieves multiple beneficial effects through innovative structural design and parameter limitations: It employs seven spherical glass lenses arranged sequentially along the optical axis, with a reasonable distribution of optical power according to a "negative-negative-negative-positive-positive-negative-positive" sequence. The fifth and sixth lenses are cemented together, and the aperture stop is positioned between the fourth and fifth lenses. Simultaneously, the refractive index of the first, second, fourth, and sixth lenses is limited to be greater than 1.9 and the Abbe number to be less than 30. The field of view (FOV) is defined to be greater than 150°, and the relative illumination greater than 94%. Key parameters such as 2.4 < f4 / f < 2.7 and 0.285 < IH / TTL < 0.31 significantly reduce processing and assembly costs and improve mass production feasibility through spherical lenses. Furthermore, the adhesive structure efficiently corrects magnification and positional chromatic aberration. Optimization of aperture position and optical power allocation reduces the propagation angle of the main rays at the edge of the field of view. By actively controlling the absolute value of the system's maximum distortion to 62%-65%, design resources are concentrated on achieving ultra-high illumination and high resolution. Simultaneously, the system's field curvature is balanced, and image plane flatness is optimized to ensure efficient matching between light and the chip. Sufficient optical back focal length provides ample space for subsequent component assembly. Ultimately, at a lower cost, it achieves ultra-wide field of view coverage, uniform brightness, clear imaging, and structural stability, meeting the stringent requirements of high-end machine vision fields such as automotive imaging and security monitoring. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a first embodiment of the wide-angle lens of the present invention; Figure 2 This is a cross-sectional structural diagram of a first embodiment of the wide-angle lens of the present invention; Figure 3 This is a simulation diagram of the optical path of a first embodiment of the wide-angle lens of the present invention; Figure 4 This is a schematic diagram of the relative illumination of a first embodiment of the wide-angle lens of the present invention; Figure 5 This is a schematic diagram of axial chromatic aberration in a first embodiment of the wide-angle lens of the present invention; Figure 6 This is a schematic diagram of the vertical chromatic aberration of a wide-angle lens embodiment of the present invention; Figure 7This is a schematic diagram of a wide-angle lens embodiment of the present invention, including a field curve and optical distortion. Figure 8 This is a schematic diagram of the MTF of a wide-angle lens embodiment of the present invention; Figure 9 This is a simulation diagram of the optical path of a second embodiment of the wide-angle lens of the present invention; Figure 10 This is a schematic diagram of the relative illumination of a second embodiment of the wide-angle lens of the present invention; Figure 11 This is a schematic diagram of axial chromatic aberration in a second embodiment of the wide-angle lens of the present invention; Figure 12 This is a schematic diagram of the lateral chromatic aberration in a second embodiment of the wide-angle lens of the present invention; Figure 13 This is a schematic diagram of field curvature and optical distortion in a second embodiment of the wide-angle lens of the present invention; Figure 14 This is a schematic diagram of the MTF of a second embodiment of the wide-angle lens of the present invention; Figure 15 This is a simulation diagram of the optical path of a third embodiment of the wide-angle lens of the present invention; Figure 16 This is a schematic diagram of the relative illumination of a third embodiment of the wide-angle lens of the present invention; Figure 17 This is a schematic diagram of axial chromatic aberration in a third embodiment of the wide-angle lens of the present invention; Figure 18 This is a schematic diagram of the vertical chromatic aberration in a third embodiment of the wide-angle lens of the present invention; Figure 19 This is a schematic diagram of the three-field curvature and optical distortion of a wide-angle lens embodiment of the present invention; Figure 20 This is a schematic diagram of the MTF of the wide-angle lens in embodiment three of the present invention; Figure 21 This is a simulation diagram of the optical path of a fourth embodiment of the wide-angle lens of the present invention; Figure 22 This is a schematic diagram of the relative illumination of a fourth embodiment of the wide-angle lens of the present invention; Figure 23 This is a schematic diagram of axial chromatic aberration in a fourth embodiment of the wide-angle lens of the present invention; Figure 24 This is a schematic diagram of the vertical chromatic aberration in a fourth embodiment of the wide-angle lens of the present invention; Figure 25 This is a schematic diagram of four-field curvature and optical distortion of a wide-angle lens embodiment of the present invention; Figure 26 This is a schematic diagram of the MTF of the fourth embodiment of the wide-angle lens of the present invention.

[0017] The meanings of the labels in the attached diagram are as follows: Lens assembly 1, first lens 11, second lens 12, third lens 13, fourth lens 14, fifth lens 15, sixth lens 16, seventh lens 17, aperture 2. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The following disclosure provides various embodiments or examples for implementing different features of the invention. Specific examples of components and arrangements will be described below to simplify the invention. Of course, these are merely examples and are not intended to limit the invention. For example, in the following description, forming a first component above or on a second component may include embodiments where the first and second components are in direct contact, or embodiments where other components may be formed between the first and second components such that the first and second components are not in direct contact. Furthermore, reference numerals and / or characters may be repeated in various instances of the invention. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations.

[0020] Furthermore, spatial relation terms such as "below," "under," "below," "above," and "above" may be used herein to readily describe the relationship between one element or component and another element (or component) or component (or component) as shown in the figure. In addition to the orientations shown in the figure, spatial relation terms will encompass various different orientations of the device in use or operation. The device may be positioned in other ways (rotated 90 degrees or in other orientations) and will be interpreted accordingly through the spatial relation descriptors used herein.

[0021] Furthermore, the technical parts described in this invention and the appended claims are primarily the improved technical parts of this invention, and do not limit the object protected by this invention to only having these technical parts. Other known essential components (structures and / or methods) and / or non-essential components of the object protected, besides the technical parts described in this invention and the appended claims, are not included in this invention and the appended claims because they do not fall within the scope of improvements of this invention; however, this does not mean that the object protected by this invention does not possess these known components.

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] Example 1: Reference Figure 1 and Figure 2 As shown, the wide-angle lens of the present invention includes a lens assembly 1 and an aperture stop 2. The lens assembly 1 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16 and a seventh lens 17 arranged sequentially from the object end to the image end along the optical axis, and the aperture stop 2 is located between the fourth lens 14 and the fifth lens 15.

[0024] The first lens 11 has negative optical power, with a convex object side and a concave image side. The first lens 11 is a convex-concave lens with ultra-high refractive index and negative optical power, having a refractive index greater than 1.90 and an Abbe number less than 30. The first lens 11 effectively expands the field of view and, through the gradual deflection of large-angle incident light rays, significantly reduces the propagation angle of the principal rays at the edge of the field of view in the wide-angle lens, thus laying the foundation for achieving a large image height in the wide-angle lens.

[0025] The second lens 12 has negative optical power, with a convex object side and a concave image side. Similar to the first lens 11, the second lens 12 is also a concave-convex lens with ultra-high refractive index and negative optical power, with a refractive index greater than 1.90 and an Abbe number less than 30. The second lens 12 effectively expands the field of view and gradually deflects large-angle incident light rays, significantly reducing the propagation angle of edge field rays in the wide-angle lens, thus laying the foundation for a large image height in the wide-angle lens. Both the first lens 11 and the second lens 12 strongly deflect and shape the light path.

[0026] The third lens 13 has negative optical power, with both its image-side and object-side surfaces being concave. The third lens 13 is a double-concave type lens with negative optical power and a refractive index of approximately 1.63. The third lens 13 satisfies |R3f| > |R3r|, where |R3f| is the absolute value of the radius of curvature of the object-side surface, and |R3r| is the absolute value of the radius of curvature of the image-side surface. The structure and position of the third lens 13 enable it to form a unique aberration precision control point in the optical path. The gently sloping object-side surface of the third lens 13 suppresses spherical aberration, ensuring that light passing through it is almost unbiased, while the strongly concave image-side surface, acting as a negative optical power unit, is used for precise control of the field area and distortion. Based on the first lens 11 and the second lens 12, the third lens 13 further optimizes the propagation of the optical path, re-regulating the light rays after beam expansion by the first and second lenses 11 and 12, allowing the light to enter subsequent lenses with a better angle and energy distribution, laying the foundation for achieving a relative illumination greater than 94%.

[0027] The fourth lens 14 has positive optical power, with a convex object side and a concave image side. The fourth lens 14 is a convex-concave lens with positive optical power and ultra-high refractive index, with a refractive index greater than 1.90 and an Abbe number less than 30. It provides the required positive optical power for wide-angle lenses, and the ultra-high refractive index can effectively correct field curvature and spherical aberration.

[0028] Aperture 2 is positioned on the side of the fourth lens 14 furthest from the third lens 13. Because the first lens 11, second lens 12, third lens 13, and fourth lens 14 sequentially deflect and adjust the light, the principal rays at the edge of the field of view can enter at a gentler angle close to that of the center field of view. This is crucial for the wide-angle lens to achieve ultra-high illumination at a 150° ultra-wide angle. Simultaneously, the placement of aperture 2 further optimizes the correction results for astigmatism and coma. Specifically, after correction by the first lens 11, second lens 12, third lens 13, and fourth lens 14, most of the astigmatism and coma have been suppressed. At this point, aperture 2, through final adjustment of the imaging beam aperture and symmetry (essentially allowing the principal rays to enter aperture 2 and subsequent lenses at a gentler angle), rebalances and optimizes the remaining astigmatism.

[0029] The fifth lens 15 has positive optical power, with a convex object-side and a convex image-side. The sixth lens 16 has negative optical power, with a concave object-side and a convex image-side. Both have a refractive index greater than 1.90 and an Abbe number less than 30. The sixth lens 16 is cemented to the fifth lens 15, which efficiently corrects chromatic aberration and positional chromatic aberration, improving image quality. Furthermore, the cemented structure reduces assembly tolerances, enhancing the overall stability and production yield of the wide-angle lens.

[0030] The seventh lens 17 has positive optical power, with both its object-side and image-side surfaces being convex. Employing a biconvex lens with positive optical power, the seventh lens 17 serves as the final lens in a wide-angle lens, precisely controlling the incident angle of the principal ray to ensure perfect alignment between the light and the chip, which forms the imaging surface. Under the control of the seventh lens 17, the principal rays at the edge of the field of view are incident on the chip's sensor at a more perpendicular and gentler angle, reducing light loss and enabling ultra-high illumination. Simultaneously, the seventh lens 17 optimizes image plane flatness, balances the system's petzwald effect, reduces system field curvature, and ensures high resolution and sharpness from the center to the edge of the field of view.

[0031] In this embodiment, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, and the seventh lens 17 can all be made of spherical glass, and the glass material makes the lens assembly 1 less expensive.

[0032] Based on the above structure: the effective focal length f of the wide-angle lens and the effective focal length f4 of the fourth lens 14 satisfy 2.4 < f4 / f < 2.7, which ensures that the fourth lens 14, as the positive power core of the wide-angle lens, can provide stable and efficient light-gathering capabilities. Simultaneously, the maximum image circle IH on the imaging plane of the wide-angle lens and the total lens length TTL satisfy 0.285 < IH / TTL < 0.31. This condition ensures that the wide-angle lens, with a total length of 24mm, has a pixel size of at least 6.9mm, ensuring a sufficiently large image plane. The effective focal length f1 of the first lens 11, the effective focal length f2 of the second lens 12, and the effective focal length f3 of the third lens 13 satisfy 0.2 < f3 / (f1+f2) < 0.25, thus ensuring that the third lens 13 can effectively perform further adjustment and aberration correction. The optical back focal length (BFL) of a wide-angle lens and its total lens length (TTL) satisfy BFL / TTL > 0.21. This ensures a sufficiently long back focal length, providing ample mounting space for filters, sensor packaging, and mechanical structures at the imaging end. This is a crucial guarantee for the practicality and mass production feasibility of the design. The maximum distortion value (DIMX) of the wide-angle lens satisfies 62% < DIMX < 65%, actively controlling optical distortion at a relatively high level of 62%~65%. This successfully concentrates design resources on achieving a relative illumination (RI) > 94% within a given total lens length. The ratio of the effective focal length (f) to the aperture size (FNO) of the wide-angle lens is equal to the entrance pupil diameter. The entrance pupil diameter of the wide-angle lens satisfies 0.9 < f / FNO < 1.1. This condition ensures that while achieving a large aperture, the entrance pupil diameter matches the focal length of the wide-angle lens, avoiding the abnormal complexity and aberration deterioration of the optical system caused by pursuing extreme parameters.

[0033] In use, light enters through the first lens 11. The light is first converged by the convex surface of the first lens 11, and then diverged by the concave surface. Since the first lens 11 has negative optical power, it generally diverges the light. The combination of convex and concave lenses can deflect light, lowering the propagation angle of the principal rays at the edge of the field of view, thus bringing the light closer to the center of the field of view. This effectively expands the field of view and lays the foundation for achieving a large image height in a wide-angle lens.

[0034] Next, the light enters the second lens 12. The light is first converged by the convex surface of the second lens 12, and then diverged by the concave surface. Because the second lens 12 has negative optical power, it generally diverges the light. The negative optical power and ultra-high refractive index of the second lens 12 further deflect the light, bringing it closer to the central field of view and further reducing the propagation angle of the principal rays in the peripheral field of view. Like the first lens 11, the second lens 12 also effectively expands the field of view of the wide-angle lens.

[0035] When light enters the third lens 13, it is first diverged by the concave surface of the third lens 13, and then further diverged by another concave surface of the third lens 13. The third lens 13 further adjusts and corrects the light after it has been deflected by the first lens 11 and the second lens 12, so that the light enters the fourth lens 14 at a gentler angle.

[0036] When light enters the fourth lens 14, it is first converged by the convex surface of the fourth lens 14, and then diverged by the concave surface of the fourth lens 14. Since the fourth lens 14 has positive optical power, it generally has a converging effect on the light. The fourth lens 14 provides the required positive optical power for the wide-angle lens and further corrects the optical path.

[0037] Light enters aperture 2, which optimizes the astigmatism and coma of the light.

[0038] Light enters the fifth lens 15 and is converged by its two convex surfaces. The sixth lens 16 is cemented to the fifth lens 15. Its concave surface first diverges the light, and its convex surface then converges the light. Since the sixth lens 16 has a negative optical power, it generally diverges the light. The fifth lens 15 and the sixth lens 16 correct the image position and improve the image quality.

[0039] Finally, the light enters the seventh lens 17, is first converged by the convex surface of the seventh lens 17, and then diverged by the concave surface of the seventh lens 17. Since the seventh lens 17 has positive optical power, the seventh lens 17 generally plays a converging role on the light. The seventh lens 17 makes the light strike the imaging surface at a gentler angle, reducing the loss of light and enabling it to achieve ultra-high illumination.

[0040] Compared with existing technologies, the wide-angle lens of this invention addresses several technical problems of existing wide-angle lenses, including low relative illumination (typically not exceeding 75%), high cost and low mass production yield due to reliance on aspherical lenses, insufficient correction of chromatic aberration and aberrations, sensitivity to assembly tolerances and poor assembly stability, and insufficient optimization of focal length ratio and the ratio of back focal length to total length. Through innovative structural design and parameter constraints, it achieves multiple beneficial effects: it employs seven spherical glass lenses arranged sequentially along the optical axis, with a reasonable distribution of optical power according to a "negative-negative-negative-positive-positive-negative-positive" sequence. The fifth and sixth lenses are cemented together, and the aperture stop is positioned between the fourth and fifth lenses. Simultaneously, the refractive index of the first, second, fourth, and sixth lenses is limited to be greater than 1.9 and the Abbe number to be less than 30. The field of view (FOV) is defined to be greater than 150°, and the relative illumination greater than 94%. Key parameters such as 2.4 < f4 / f < 2.7 and 0.285 < IH / TTL < 0.31 significantly reduce processing and assembly costs and improve mass production feasibility through spherical lenses. Furthermore, the adhesive structure efficiently corrects magnification and positional chromatic aberration. Optimization of aperture position and optical power allocation reduces the propagation angle of the main ray at the edge of the field of view, actively controlling the maximum absolute value of system distortion to 62%-65%. Design resources are concentrated on achieving ultra-high illumination and high resolution, while balancing system field curvature and optimizing image plane flatness to ensure efficient matching of light and chip. Sufficient optical back focal length provides ample space for subsequent component assembly. Ultimately, at a relatively low cost, it achieves ultra-wide field of view coverage, uniform brightness, clear imaging, and structural stability, meeting the stringent requirements of high-end machine vision fields such as automotive imaging and security monitoring. The main design parameters of this embodiment are shown in Table 1 below:

[0041] To achieve the above design parameters, the specific design adopted in this embodiment is shown in Table 2 below:

[0042] It should be noted that OBJ is the object plane, S1 and S2 are the object-side and image-side planes of the first lens, respectively, S3 and S4 are the object-side and image-side planes of the second lens, respectively, S5 and S6 are the object-side and image-side planes of the third lens, respectively, S7 and S8 are the object-side and image-side planes of the fourth lens, ST0 is the aperture plane, S9 and S10 are the object-side and image-side planes of the fifth lens, respectively, S10 and S11 are the object-side and image-side planes of the sixth lens (S10 is the cemented surface of the fifth and sixth lenses), and S12 and S13 are the object-side and image-side planes of the seventh lens, respectively.

[0043] The wide-angle lens in this embodiment achieves superior performance at a lower cost by using seven spherical glass elements. Figure 4 As shown, the lens has a relative illumination (RI) > 96.6%, achieving ultra-high illumination even with a wide-angle lens; Figure 5 As shown, in this embodiment, the axial color difference offset is controlled within -0.01mm to 0.035mm. m Within this range, it indicates that the lens can effectively correct axial chromatic aberration; such as Figure 6 As shown, the chromatic aberration along the vertical axis in this embodiment is within 0~2.5µm; this indicates that the lens can effectively correct chromatic aberration; and as... Figure 7 As shown, the field curvature of the system's meridional and sagittal image planes is controlled within -0.02mm to 0.04mm, indicating that the system's field curvature correction is good. Figure 8 The system shown achieves a maximum field of view of over 0.58 at 100 line pairs / mm, demonstrating high resolution. This invention, through a seven-spherical lens design, elevates the system's relative illumination to an extremely high level, achieving highly uniform brightness without complex software correction, thus reducing system power consumption and processing latency. It significantly improves the signal-to-noise ratio and detail reproduction capability in edge areas, making it particularly suitable for automotive vision systems and security monitoring applications with extremely high requirements for image quality and reliability.

[0044] Example 2: The shape of this embodiment is as follows: Figure 9 As shown, the main differences from Embodiment 1 are the material, curvature, and thickness of the lens, and the surface shape of the third lens is also different. In this embodiment, the object-side surface of the third lens is convex. The main design parameters of this embodiment are shown in Table 3 below:

[0045] To achieve the above design parameters, the specific design adopted in this embodiment is shown in Table 4 below:

[0046] The wide-angle lens in this embodiment is the same as in Embodiment 1, using seven spherical glass elements to achieve superior performance at a lower cost; such as Figure 10 As shown, this embodiment exhibits an ultra-high illumination with a lens relative illumination RI > 98.3%, such as... Figure 11 As shown; in this embodiment, the axial color difference offset is controlled within -0.01mm to 0.035mm. m Within this range, it indicates that the lens can effectively correct axial chromatic aberration; such as Figure 12 As shown, the chromatic aberration along the vertical axis in this embodiment is within 0~3µm; this indicates that the lens can effectively correct chromatic aberration; and as... Figure 13 As shown, the field curvature of the system's meridional and sagittal image planes is controlled within -0.015mm to 0.035mm, indicating that the system's field curvature correction is good. Figure 14 The system shown has a maximum field of view of over 0.58 at 100 line pairs / mm, indicating high resolution.

[0047] Example 3: The shape of this embodiment is as follows Figure 15 As shown, the difference between this embodiment and Embodiment 1 lies in the material, curvature, and thickness of the lens, as well as the surface shape of the fourth lens. In this embodiment, the image-side surface of the fourth lens is convex. The main design parameters of this embodiment are shown in Table 5 below:

[0048] To achieve the above design parameters, the specific design adopted in this embodiment is shown in Table 6 below:

[0049] The wide-angle lens in this embodiment is the same as in Embodiment 1, using seven spherical glass elements to achieve superior performance at a lower cost. Figure 16 As shown, the lens has a relative illumination RI > 94.6%, as... Figure 17 As shown; in this embodiment, the axial color difference offset is controlled within -0.01mm to 0.03mm. m Within this range, it indicates that the lens can effectively correct axial chromatic aberration; such as Figure 18 As shown, the chromatic aberration along the vertical axis in this embodiment is within 0~2.5µm; this indicates that the lens can effectively correct chromatic aberration; and as... Figure 19 As shown, the field curvature of the system's meridional and sagittal image planes is controlled within -0.015mm to 0.035mm, indicating that the system's field curvature correction is good. Figure 20 As shown, the system resolution is above 0.58 at a maximum field of view of 100 line pairs / mm, indicating high resolution.

[0050] Example 4: The shape of this embodiment is as follows Figure 21 As shown, the difference between this embodiment and Embodiment 1 is the use of a larger aperture of F-number 2.54, and the curvature and thickness of the lens are different; the main design parameters of this embodiment are shown in Table 7 below:

[0051] To achieve the above design parameters, the specific design adopted in this embodiment is shown in Table 8 below:

[0052] The wide-angle lens in this embodiment is the same as in Embodiment 1, using seven spherical glass elements to achieve superior performance at a lower cost. Figure 22 As shown, the system's relative illumination RI > 96.8%; Figure 23 As shown; in this embodiment, the axial color difference offset is controlled within -0.015mm to 0.045mm. m Within this range, it indicates that the lens can effectively correct axial chromatic aberration; such as Figure 24As shown, the chromatic aberration along the vertical axis in this embodiment is within 0~3µm; this indicates that the lens can effectively correct chromatic aberration; and as... Figure 25 As shown, the field curvature of the system's meridional and sagittal image planes is controlled within -0.005mm to 0.05mm, indicating that the system's field curvature correction is good. Figure 26 As shown, the system resolution is high, with a maximum field of view of over 0.58 at 100 line pairs / mm.

[0053] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A wide-angle lens, comprising a lens assembly and an aperture stop, characterized in that: The lens assembly comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object end to the image end along the optical axis. The first lens has negative optical power, with a convex object-side surface and a concave image-side surface; the second lens has negative optical power, with a convex object-side surface and a concave image-side surface; the third lens has negative optical power, with a concave image-side surface; the fourth lens has positive optical power, with a convex object-side surface; and the fifth lens has positive optical power. The object-side surface of the lens is convex, and the image-side surface is convex. The sixth lens has negative optical power, its object-side surface is concave, and its image-side surface is convex. The sixth lens is cemented with the fifth lens. The seventh lens has positive optical power, its object-side surface is convex, and its image-side surface is convex. The aperture stop is located between the fourth lens and the fifth lens. The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the effective focal length f3 of the third lens of the wide-angle lens satisfy 0.2 < f3 / (f1+f2) < 0.

25.

2. The wide-angle lens as described in claim 1, characterized in that: The wide-angle lens has a field of view (FOV) greater than 150° and a relative illumination greater than 94%.

3. The wide-angle lens as described in claim 1, characterized in that: The effective focal length f of the wide-angle lens and the effective focal length f4 of the fourth lens satisfy 2.4 < f4 / f < 2.

7.

4. The wide-angle lens as described in claim 1, characterized in that: The maximum image circle IH on the imaging plane of the wide-angle lens and the total lens length TTL satisfy 0.285 < IH / TTL < 0.

31.

5. The wide-angle lens as described in claim 1, characterized in that: The optical back focal length BFL of the wide-angle lens and the total lens length TTL satisfy BFL / TTL > 0.

21.

6. The wide-angle lens as described in claim 1, characterized in that: The maximum distortion value DIMX of the wide-angle lens satisfies 62% < DIMX < 65%.

7. The wide-angle lens as described in claim 1, characterized in that: The ratio of the effective focal length f to the aperture size FNO of the wide-angle lens is the entrance pupil diameter, and the entrance pupil diameter of the wide-angle lens satisfies 0.9 < f / FNO < 1.

1.

8. The wide-angle lens as described in claim 1, characterized in that: The refractive indices of the first lens, the second lens, the fourth lens, and the sixth lens are all greater than 1.90, and the Abbe numbers of the first lens, the second lens, the fourth lens, and the sixth lens are all less than 30.

9. The wide-angle lens according to any one of claims 1 to 8, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can all be made of spherical glass.

Images