Super-definition distortionless face recognition lens

Abstract

The utility model provides a super-definition distortionless face recognition lens, particularly relates to the technical field of camera lenses, and is used for solving the technical problems that an existing face recognition lens is poor in stability in a high-temperature environment, the image quality is easily interfered at night or under a complex light condition, and the use effect is affected. The lens comprises a lens shell, and a first lens element, a second lens element, a third lens element, a fourth lens element, a diaphragm, a fifth lens element, a sixth lens element, a seventh lens element, an eighth lens element, a cover, a rear cover and a lens barrel which are arranged in the lens shell from an object side to an image side in sequence. According to the utility model, various aberrations are effectively suppressed and corrected, so that a wide field angle, good aperture control and a clear imaging effect are realized, meanwhile, a stable and high-quality imaging effect can still be kept in a complex light and high-temperature environment, and the lens is particularly suitable for diversified requirements in various face recognition and monitoring scenes.

Description

Technical Field

[0001] This utility model relates to the field of camera lens technology, and more specifically, to an ultra-high-definition distortion-free face recognition lens. Background Technology

[0002] Currently, facial recognition technology is widely used in various fields, and its performance directly determines the effectiveness of these applications. However, existing optical lenses still have many shortcomings in terms of recognition accuracy and distortion control. Lenses using traditional optical designs may maintain a clear image in the center of the face, but blurring or distortion at the edges is common, especially in wide-angle lenses where image distortion is more pronounced, affecting the accuracy of facial recognition.

[0003] Furthermore, as people's demands for image quality increase, 2K pixel level lenses have become the industry's goal. To achieve 2K pixels, existing optical lenses require more lens elements and more complex optical structures, which not only increases lens costs but also increases lens thickness and weight, making lens design and installation more complicated.

[0004] Meanwhile, special applications, such as working in high-temperature environments or using the lens at night or in complex lighting conditions, place higher demands on its durability and adaptability. Existing lenses exhibit poor stability in high-temperature environments, and image quality is easily affected by interference under nighttime or complex lighting conditions, impacting usability. Therefore, developing an ultra-high-definition, distortion-free face recognition optical lens that can meet the requirements of high definition, distortion-free performance, high-temperature resistance, and use under complex lighting conditions is of significant practical importance. Utility Model Content

[0005] The purpose of this invention is to provide an ultra-high-definition distortion-free face recognition lens that effectively suppresses and corrects various aberrations, thereby achieving a wide field of view, good aperture control, and clear imaging effect. At the same time, it can maintain stable and high-quality imaging effect even in complex lighting and high-temperature environments, and is specifically suitable for diverse needs in various face recognition and monitoring scenarios.

[0006] The embodiments of this utility model are achieved through the following technical solutions:

[0007] An ultra-high-definition distortion-free face recognition lens includes a lens housing and a first lens element, a second lens element, a third lens element, a fourth lens element, an aperture, a fifth lens element, a sixth lens element, a seventh lens element, an eighth lens element, a cover, a rear cover, and a lens barrel arranged sequentially from the object side to the image side inside the lens housing.

[0008] The first lens element is a meniscus lens; the second lens element is a meniscus lens; the third lens element is a meniscus lens; the fourth lens element is a biconvex lens; the aperture stop is the diameter controlling the aperture size; the fifth lens element is a meniscus lens; the sixth lens element is a plano-convex lens; the seventh lens element is a meniscus lens; and the eighth lens element is a biconvex lens.

[0009] The mirror surface of the sixth lens element mates with the object surface of the seventh lens element;

[0010] The first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element, the seventh lens element, and the eighth lens element are all glass lens elements.

[0011] In some embodiments, the first to eighth lens elements respectively satisfy the following condition formulas: Nd1≥1.78800, Vd1≥47.50; Nd2≥1.78800, Vd2≥47.50; Nd3≥1.78800, Vd3≥47.50; Nd4≥1.92286, Vd4≥20.88; Nd5≥1.51700, Vd5≥64.20; Nd6≥1.49100, Vd6≥57.40; Nd7≥1.88300, Vd7≥40.50; Nd8≥1.88300, Vd8≥4 0.50; where Nd1, Nd2, Nd3, Nd4, Nd5, Nd6, Nd7, and Nd8 represent the d-ray refractive indices of the materials of the first, second, third, fourth, fifth, sixth, seventh, and eighth lens elements, respectively, and Vd1, Vd2, Vd3, Vd4, Vd5, Vd6, Vd7, and Vd8 represent the d-ray Abbe constants of the materials of the first, second, third, fourth, fifth, sixth, seventh, and eighth lens elements, respectively.

[0012] In some embodiments, an aperture stop is also included, which is disposed between the third lens element and the fourth lens element.

[0013] In some embodiments, a ninth lens element is further included, disposed inside the lens housing and located on the image side of the eighth lens element. The ninth lens element is a biconvex lens and satisfies the following formulas: Nd9 ≥ 1.43800, Vd9 ≥ 95.0; where Nd9 is the d-ray refractive index of the material of the ninth lens element and Vd9 is the d-ray Abbe constant of the material of the ninth lens element.

[0014] In some embodiments, the distance from the outermost point on the object side of the first lens element to the imaging surface must satisfy the following formula: total optical length S4 = 28.7 ± 0.3 mm.

[0015] In some embodiments, the lens housing is made of all-metal material.

[0016] In some embodiments, the total height of the lens assembly S2 = 21.26 ± 0.3 mm; the total height of the finished lens S3 = 22.6 ± 0.3 mm; the total height of the mechanism S5 = 24.1 ± 0.3 mm; the mechanical back focal length S6 = 3.8 ± 0.1 mm; and the optical back focal length S7 = 3.0 ± 0.1 mm.

[0017] In some embodiments, the surfaces of the first lens element and the ninth lens element are provided with an infrared cutoff film.

[0018] In some embodiments, the sixth lens element L6 is an aspherical lens.

[0019] In some embodiments, the surfaces of the first lens element L1 to the eighth lens element L8 are all coated with multilayer broadband antireflection films.

[0020] The technical solution of this utility model embodiment has at least the following advantages and beneficial effects:

[0021] 1. This utility model comprises a lens housing, eight lens elements (first to eighth lens elements), an aperture stop, a cover, and a rear cover. The first to eighth lens elements are arranged sequentially. The first to fourth lens elements are used to correct off-axis aberrations, while the fifth to eighth lens elements further optimize the overall image quality. The aperture stop is used to adjust the aperture size, and the cover and rear cover serve to fix and protect the lenses. Furthermore, the lens possesses high-temperature resistance, enabling normal operation in environments exceeding 100 degrees Celsius. The lens has a diagonal field of view of 95°, with optical distortion controlled within 2.1%, ensuring image quality over a wide viewing angle. In its working principle, multiple lenses, through precise arrangement and coordination, form a powerful optical system that effectively suppresses and corrects various aberrations, thereby achieving a wide field of view, excellent aperture control, and clear imaging. Simultaneously, it maintains stable and high-quality imaging even under complex lighting and high-temperature environments, making it suitable for diverse needs in various face recognition and surveillance scenarios. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model;

[0024] Figure 2 This is a schematic diagram showing the external dimensions of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model;

[0025] Figure 3 A schematic diagram illustrating the imaging process of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model;

[0026] Figure 4 A field curvature curve diagram of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model;

[0027] Figure 5 A vertical axis chromatic aberration curve of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model;

[0028] Figure 6 An axial chromatic aberration curve of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model;

[0029] Figure 7 The distortion-free curve of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model;

[0030] Figure 8 The MTF curve of an ultra-high-definition distortion-free face recognition lens provided in an embodiment of this utility model.

[0031] Icons: 1. Lens housing; 2. Aperture; L1. First lens element; L2. Second lens element; L3. Third lens element; L4. Fourth lens element; L5. Fifth lens element; L6. Sixth lens element; L7. Seventh lens element; L8. Eighth lens element. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this utility model, it should be noted that if terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0036] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0037] Please see Figures 1-3 As shown, the main body of this embodiment is an ultra-high-definition distortion-free face recognition lens, including a lens housing 1 and a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, an aperture 2, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7, an eighth lens element L8 arranged sequentially from the object side to the image side inside the lens housing 1, along with a cover, a rear cover, and a lens barrel.

[0038] The first lens element L1 is a meniscus lens; the second lens element L2 is a meniscus lens; the third lens element L3 is a meniscus lens; the fourth lens element L4 is a biconvex lens; the aperture stop 2 is the diameter controlling the aperture size; the fifth lens element L5 is a meniscus lens; the sixth lens element L6 is a plano-convex lens; the seventh lens element L7 is a meniscus lens; and the eighth lens element L8 is a biconvex lens.

[0039] The mirror surface of the sixth lens element L6 mates with the object surface of the seventh lens element L7;

[0040] The first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7, and the eighth lens element L8 are all glass lens elements.

[0041] Furthermore, the first lens element L1 to the eighth lens element L8 (L8) respectively satisfy the following condition formulas: Nd1≥1.78800, Vd1≥47.50; Nd2≥1.78800, Vd2≥47.50; Nd3≥1.78800, Vd3≥47.50; Nd4≥1.92286, Vd4≥20.88; Nd5≥1.51700, Vd5≥64.20; Nd6≥1.49100, Vd6≥57.40; Nd7≥1.88300, Vd7≥40.50; Nd8≥1.88300, Vd8≥40.50; where Nd1, Nd... 2. Nd3, Nd4, Nd5, Nd6, Nd7, and Nd8 represent the d-optical refractive indices of the materials of the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7, and the eighth lens element L8, respectively. Vd1, Vd2, Vd3, Vd4, Vd5, Vd6, Vd7, and Vd8 represent the d-optical Abbe constants of the materials of the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7, and the eighth lens element L8, respectively. The high refractive indices of the first to third lens elements L3, combined with a medium-high Abbe number, optimize chromatic aberration stability at high temperatures. Furthermore, the average Vd of the first group (L1-L4) is approximately 34, and the average Vd of the latter group (L5-L8) is approximately 65, forming a complementary chromatic aberration structure.

[0042] Furthermore, the distance from the outermost point of the first lens element L1 on the object side to the imaging plane must satisfy the following formula: total optical length S4 = 28.7 ± 0.3 mm.

[0043] Furthermore, the lens housing 1 is made entirely of metal.

[0044] Furthermore, the total height of the lens assembly is S2 = 21.26 ± 0.3 mm; the total height of the finished lens is S3 = 22.6 ± 0.3 mm; the total height of the mechanism is S5 = 24.1 ± 0.3 mm; the mechanical back focal length is S6 = 3.8 ± 0.1 mm; and the optical back focal length is S7 = 3.0 ± 0.1 mm.

[0045] Furthermore, the surfaces of the first lens element L1 and the eighth lens element L8 are provided with infrared cut-off films, wherein the wavelength is >850 nm and the reflectivity is >95%, in order to suppress infrared noise at night and improve the nighttime usability of the lens.

[0046] Furthermore, the sixth lens element L6 is an aspherical lens, thereby suppressing spherical aberration and reducing the effects of thermal deformation.

[0047] Furthermore, the surfaces of the first lens element L1 to the eighth lens element L8 are all coated with multilayer broadband anti-reflection films. The broadband anti-reflection films are made of alternating MgF2 / ZrO2 films, which makes the lens reflectivity <0.5% and the light transmittance increased to 99.3%. It also reduces reflection loss under nighttime infrared illumination or complex light sources, improves light transmittance, and suppresses glare and ghosting.

[0048] Furthermore, along the optical axis from the object side to the image side, within the lens housing 1: the object surface of the first lens element L1 has a mirror curvature radius of R1, and the mirror surface has a mirror curvature radius of R2; the object surface of the second lens element L2 has a mirror curvature radius of R3, and the mirror surface has a mirror curvature radius of R4; the object surface of the third lens element L3 has a mirror curvature radius of R5, and the mirror surface has a mirror curvature radius of R6; the object surface of the fourth lens element L4 has a mirror curvature radius of R7, and the mirror surface has a mirror curvature radius of R8; the object surface of the fifth lens element L5... The object surface of the sixth lens element L6 has a mirror curvature radius of R9, and the object surface of the seventh lens element L7 has a mirror curvature radius of R10; the object surface of the eighth lens element L8 has a mirror curvature radius of R11, and the object surface of the ninth lens element L9 has a mirror curvature radius of R16, and the object surface of the ninth lens element L9 has a mirror curvature radius of R17. Among these, the eighth lens element has R14 = 18.3 mm and R15 = -22.1 mm, resulting in an increased field of view of 95° and reduced edge distortion to 2.1%.

[0049] Figures 4 to 8 This is a graph showing the optical performance of this embodiment, wherein, Figure 4 This is a field curvature curve, reflecting the change in the focal position of the lens at different field angles (or image heights); Figure 5 This is a chromatic aberration curve, represented by the wavelengths of the commonly used F, d, and C colors, with units in μm; Figure 6 This is an axial chromatic difference curve, represented by the wavelengths of the commonly used F, d, and C colors of light, with units in mm; Figure 7 The graph shows the distortion-free curves, representing the distortion-free values ​​for different field-of-view angles, in percentage (%). Figure 8 The MTF curve represents the overall resolution level of an optical system.

[0050] This utility model comprises a lens housing, eight lens elements (first to eighth lens elements), an aperture stop, a cover, and a rear cover. The first to eighth lens elements are arranged sequentially; the first to fourth lens elements correct off-axis aberrations, while the fifth to eighth lens elements further optimize overall image quality. The aperture stop adjusts the aperture size, and the cover and rear cover secure and protect the lenses. Furthermore, the lens possesses high-temperature resistance, enabling normal operation in environments exceeding 100 degrees Celsius. The lens has a diagonal field of view of 95°, with optical distortion controlled within 2.1%, ensuring high-quality imaging over a wide viewing angle. In its working principle, multiple lenses, precisely arranged and coordinated, form a powerful optical system that effectively suppresses and corrects various aberrations, thereby achieving a wide field of view, excellent aperture control, and clear imaging. It maintains stable and high-quality imaging even under complex lighting and high-temperature environments, making it suitable for diverse needs in various face recognition and surveillance scenarios.

[0051] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A high-definition, distortion-free face recognition lens, characterized in that, It includes a lens housing (1) and a first lens element (L1), a second lens element (L2), a third lens element (L3), a fourth lens element (L4), an aperture stop (2), a fifth lens element (L5), a sixth lens element (L6), a seventh lens element (L7), an eighth lens element (L8) arranged in sequence from the object side to the image side inside the lens housing (1), as well as a cover, a rear cover and a lens barrel; The first lens element (L1) is a meniscus lens; the second lens element (L2) is a meniscus lens; the third lens element (L3) is a meniscus lens; the fourth lens element (L4) is a biconvex lens; the aperture stop (2) is the diameter that controls the aperture size; the fifth lens element (L5) is a meniscus lens; the sixth lens element (L6) is a plano-convex lens; the seventh lens element (L7) is a meniscus lens; and the eighth lens element (L8) is a biconvex lens. The mirror surface of the sixth lens element (L6) mates with the object surface of the seventh lens element (L7); The first lens element (L1), the second lens element (L2), the third lens element (L3), the fourth lens element (L4), the fifth lens element (L5), the sixth lens element (L6), the seventh lens element (L7), and the eighth lens element (L8) are all glass lens elements.

2. The ultra-high-definition distortion-free face recognition lens according to claim 1, characterized in that: The first lens element (L1) to the eighth lens element (L8) respectively satisfy the following condition formulas: Nd1≥1.78800, Vd1≥47.50; Nd2≥1.78800, Vd2≥47.50; Nd3≥1.78800, Vd3≥47.50; Nd4≥1.92286, Vd4≥20.88; Nd5≥1.51700, Vd5≥64.20; Nd6≥1.49100, Vd6≥57.40; Nd7≥1.88300, Vd7≥40.50; Nd8≥1.88300, Vd8≥40.50; where Nd1, Nd2, Nd3, Nd4, Nd5, Nd6, and Nd7 are the lens elements with the following properties: Nd1≥1.78800, Vd1≥47.50; Nd2≥1.78800, Vd3≥47.50; Nd3≥1.78800, Vd4≥47.50; Nd4≥1.92286, Vd4≥20.88; Nd5≥1.51700, Vd5≥64.20; Nd6≥1.49100, Vd6≥57.40; Nd7≥1.88300, Vd7≥40.50; Nd8≥1.88300, Vd8≥40.50; where Nd1, Nd2, Nd3, Nd4, Nd5, Nd6, and Nd7 are the lens elements with the following properties: Nd1≥1.78800, Vd1≥47.50; Nd2≥1.78800, Vd3≥47.50; Nd4≥1.88300, Vd d7 and Nd8 represent the d-ray refractive indices of the materials of the first lens element (L1), the second lens element (L2), the third lens element (L3), the fourth lens element (L4), the fifth lens element (L5), the sixth lens element (L6), the seventh lens element (L7), and the eighth lens element (L8), respectively. Vd1, Vd2, Vd3, Vd4, Vd5, Vd6, Vd7, and Vd8 represent the d-ray Abbe constants of the materials of the first lens element (L1), the second lens element (L2), the third lens element (L3), the fourth lens element (L4), the fifth lens element (L5), the sixth lens element (L6), the seventh lens element (L7), and the eighth lens element (L8), respectively.

3. The ultra-high-definition distortion-free face recognition lens according to claim 1, characterized in that: The distance from the outermost point of the first lens element (L1) on the object side to the imaging plane must satisfy the following formula: total optical length S4 = 28.7 ± 0.3 mm.

4. The ultra-high-definition distortion-free face recognition lens according to claim 1, characterized in that: The lens housing (1) is made of all-metal material.

5. The ultra-high-definition distortion-free face recognition lens according to claim 1, characterized in that: The total height of the lens assembly is S2 = 21.26 ± 0.3 mm; the total height of the finished lens is S3 = 22.6 ± 0.3 mm; the total height of the mechanism is S5 = 24.1 ± 0.3 mm; the mechanical back focal length is S6 = 3.8 ± 0.1 mm; and the optical back focal length is S7 = 3.0 ± 0.1 mm.

6. The ultra-high-definition distortion-free face recognition lens according to claim 4, characterized in that: The surfaces of the first lens element (L1) and the eighth lens element (L8) are provided with infrared cut-off films.

7. The ultra-high-definition distortion-free face recognition lens according to claim 1, characterized in that: The sixth lens element (L6) is an aspherical lens.

8. The ultra-high-definition distortion-free face recognition lens according to claim 1, characterized in that: The surfaces of the first lens element (L1) to the eighth lens element (L8) are all coated with multilayer broadband antireflection films.

Images