A large-aperture industrial vision detection lens applied to a vehicle lamp self-closing loop

Abstract

The application discloses a large-aperture industrial vision detection lens applied to a vehicle lamp self-closing loop, which comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from an object side to an image side along an optical axis direction; wherein the first lens, the third lens and the fourth lens each have a positive focal length; and the second lens and the fifth lens each have a negative focal length. Through the lens, the aperture size can be increased to enhance the light collection capability, the lens size can be optimized, and the temperature adaptability can be improved.

Description

Technical Field

[0001] The present invention relates to the field of industrial vision technology, and in particular to a large-aperture industrial vision inspection lens applied to a self-closing loop of a vehicle lamp. Background Art

[0002] With the development of intelligent technology, headlights, serving as the "night eyes" of cars, have evolved from traditional, single-use illumination to intelligent projection and interactive features, placing higher demands on automated production and inspection. Industrial visual inspection based on a closed-loop system for headlights is a key process in automated headlight manufacturing. It relies on computer vision technology to detect, identify, measure, and locate products during the production process. Imaging lenses, as a key component of the vision system, accurately transmit optical image information of the target object to the image sensor, providing the foundation for subsequent intelligent recognition algorithms. Selecting the appropriate imaging lens is crucial to ensuring high-quality image acquisition.

[0003] Traditional five-element industrial vision lenses have a small aperture, typically ranging from F2.2 to F2.8. This means they have limited light collection in low-light conditions, resulting in insufficient image brightness. Their large size, however, is inconsistent with modern compact design requirements, limiting their application in space-constrained environments. Their performance is also unstable when operating in varying temperatures, impacting image quality.

[0004] Therefore, it is necessary to design a new lens to increase the aperture size to enhance the light collection ability, optimize the lens size, and improve temperature adaptability. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a large aperture industrial vision inspection lens for use in a self-closing loop of a vehicle lamp.

[0006] In order to solve the above technical problems, the purpose of the present invention is achieved through the following technical solutions: providing a large aperture industrial vision inspection lens applied to the self-closing loop of vehicle lamps, comprising: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the object side to the image side along the optical axis; wherein, the first lens, the third lens, and the fourth lens respectively have positive optical focal lengths; and the second lens and the fifth lens respectively have negative optical focal lengths.

[0007] A further technical solution is as follows: a system aperture is provided between the second lens and the third lens; and a vignetting aperture is provided on a surface of the second lens close to the first lens.

[0008] A further technical solution is as follows: the first lens includes a convex lens with positive optical power, the material of the first lens is crown glass, the refractive index of the first lens is between 1.6 and 1.8, and the Abbe number of the first lens is between 40 and 60.

[0009] A further technical solution is: the second lens includes a concave lens with negative optical power, the material of the second lens is heavy flint glass, the refractive index of the second lens is greater than 1.7, and the Abbe number of the second lens is greater than 20.

[0010] A further technical solution is as follows: the third lens comprises a convex lens with positive optical power, the material of the third lens is crown glass, the refractive index of the third lens is between 1.2 and 1.7, and the Abbe number of the third lens is greater than 40.

[0011] A further technical solution is as follows: the fourth lens comprises a convex lens with positive optical power, the material of the fourth lens is crown glass, the refractive index of the fourth lens is between 1.5 and 1.7, and the Abbe number of the fourth lens is between 40 and 60.

[0012] A further technical solution is: the fifth lens includes a concave lens with negative optical power, the material of the fifth lens is heavy flint glass, the refractive index of the fifth lens is between 1.6 and 1.8, and the Abbe number of the fifth lens is between 20 and 40.

[0013] A further technical solution is: the optical distance between the first lens and the second lens is 0.5 mm, and the optical distance between the second lens and the third lens is 3.1 mm.

[0014] A further technical solution is: the optical interval between the third lens and the fourth lens is 0.8 mm, and the optical interval between the fourth lens and the fifth lens is 1.6 mm.

[0015] A further technical solution is: the optical distance between the fifth lens and the image plane is 1.6 mm.

[0016] The beneficial effects of the present invention compared with the prior art are as follows: the present invention designs a large aperture combination in the lens system, adopts the first, third and fourth lenses as positive optical power lenses, and the second and fifth lenses as negative optical power lenses, thereby being able to effectively collect and focus light, thereby increasing the aperture size; the configuration of the positive and negative optical power lenses optimizes the propagation path of light, so that the system can reduce the size of the optical structure while ensuring optical performance, thereby achieving a compact design; reasonable lens material and optical spacing design enable the lens to maintain stable optical performance at different ambient temperatures; ultimately achieving higher light collection capability, smaller lens size and good temperature adaptability.

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic structural diagram of a large-aperture industrial vision inspection lens for a self-closing loop of a headlight, provided by an embodiment of the present invention;

[0020] Figure 2 A spot diagram of a large-aperture industrial vision inspection lens for a self-closing loop of a headlight, provided by an embodiment of the present invention;

[0021] Figure 3 A light fan diagram provided by an embodiment of the present invention;

[0022] Figure 4 Field curvature and distortion diagrams provided by embodiments of the present invention;

[0023] Figure 5 A vertical axis chromatic aberration diagram provided by an embodiment of the present invention;

[0024] Figure 6 A diagram of the light transfer function at 25° ambient temperature provided by an embodiment of the present invention;

[0025] Figure 7 85° ambient light transfer function diagram provided by an embodiment of the present invention;

[0026] Figure 8 A diagram of the light transfer function for a 105° environment provided by an embodiment of the present invention;

[0027] Description of the symbols in the figure:

[0028] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; S5, system aperture; S12, imaging surface. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0031] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0032] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0033] Industrial vision relies on computer vision technology for automated inspection. The imaging lens is a key component, responsible for accurately transmitting optical images to the image sensor. Selecting the right lens is crucial for obtaining high-quality images. Traditional five-element lenses have a small aperture, limiting their ability to collect light in low-light conditions, which affects image brightness. Their large size makes them difficult to meet the demands of modern compact designs, limiting their application in space-constrained environments. Their performance also fluctuates under varying temperatures, impacting image quality.

[0034] To this end, an embodiment of the present invention provides a large aperture industrial vision inspection lens applied to the self-closing loop of vehicle lamps, which increases the aperture size to enhance the light collection capability, optimizes the lens size, and improves temperature adaptability.

[0035] Specifically, this lens optimizes its optical performance by designing an optical system with multiple lens combinations. In particular, the large aperture design significantly improves image brightness in low-light environments, addressing the issue of insufficient brightness in traditional lenses. The lens utilizes a combination of positive-power first lens 1, third lens 3, and fourth lens 4, and negative-power second lens 2 and fifth lens 5, enhancing image quality while ensuring high brightness in low-light environments. By placing an aperture stop between second lens 2 and third lens 3, and a vignetting stop on the side of second lens 2 closest to first lens 1, the brightness distribution of the image is effectively controlled, improving imaging in low-light environments. The precise selection of lens materials and refractive indices (such as crown glass and heavy flint glass) optimizes optical transmission characteristics, ensuring image quality and brightness at large apertures. The lens design ensures optimal optical spacing, reducing light loss in traditional lenses under low-light conditions and effectively improving light utilization. While maintaining a small optical size, this sophisticated optical design overcomes the bulkiness of traditional lenses, making the lens more compact and suitable for industrial vision applications.

[0036] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0037] See also Figure 1 A large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp comprises: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a fifth lens 5, which are arranged in sequence along the optical axis from the object side to the image side; wherein the first lens 1, the third lens 3, and the fourth lens 4 each have positive optical power; and the second lens 2 and the fifth lens 5 each have negative optical power.

[0038] In one embodiment, see Figure 1 A system aperture S5 is provided between the second lens 2 and the third lens 3 ; a vignetting stop is provided on a surface of the second lens 2 close to the first lens 1 .

[0039] Specifically, a system diaphragm S5 is positioned between the second and third lens elements (surface S5) to control the amount of light entering the system. Simultaneously, a vignetting diaphragm (surface S3) is positioned on the side of the second lens element 2 closest to the first lens element 1 to effectively control vignetting aberrations in the off-axis field of view, ensuring image quality in peripheral areas. This dual-diaphragm design helps optimize imaging performance, particularly when processing images under complex lighting conditions.

[0040] The system parameters of the lens are shown in Table 1, and the surface parameters are shown in Table 2.

[0041] Table 1. System parameters

[0042] EFL 11.11 BFL 1.61 F / # 2 FOV ±15°

[0043] Table 2. Surface parameters

[0044] Surf Type Radius Thickness Nd Vd Physical Surface STANDARD Infinity 1000 S1 STANDARD 8.710 9.902 1.713 53.833 S2 STANDARD -23.470 0.503 S3 STANDARD -11.630 1.797 1.740 28.292 S4 STANDARD 51.199 1.226 S5(STO) STANDARD Infinity 1.960 S6 STANDARD 30.704 1.448 1.665 54.658 S7 STANDARD -12.121 0.767 S8 STANDARD 11.692 2.000 1.697 55.526 S9 STANDARD 60.866 1.557 S10 STANDARD -5.987 2.033 1.74 28.292 S11 STANDARD 39.185 1.613 S12(IMA) STANDARD Infinity

[0045] The above S1~S12 are respectively Figure 1 The surfaces of each lens, the system aperture S5 and the imaging surface S12 correspond to each other.

[0046] According to the system parameters in Table 1, we can know that:

[0047] EFL (effective focal length): 11.11mm;

[0048] BFL (back focal length): 1.61mm;

[0049] F / # (aperture number): 2.0, indicating that this is a large aperture lens capable of capturing brighter images in low-light conditions.

[0050] FOV (Field of View): ±15°, which means that the lens can cover a wider viewing angle range and is suitable for a variety of application scenarios.

[0051] Table 2 lists the type, radius, thickness, and corresponding refractive index (Nd) and Abbe number (Vd) of each surface, as follows:

[0052] The first lens 1 is made of crown glass, which has a refractive index of 1.713 and an Abbe number of 53.833, which helps to reduce dispersion and improve transmittance.

[0053] The second lens 2 is made of heavy flint glass with a refractive index greater than 1.7 and an Abbe number greater than 20 to increase dispersion and better correct chromatic aberration.

[0054] The third lens element 3 is also made of crown glass with a refractive index between 1.2 and 1.7 and an Abbe number greater than 40, which further optimizes chromatic aberration correction.

[0055] The fourth lens element 4 is also made of crown glass, with a refractive index between 1.5 and 1.7 and an Abbe number between 40 and 60, which helps to adjust the overall length of the system and maintain excellent imaging quality.

[0056] The fifth lens 5 is again made of heavy flint glass with a refractive index between 1.6 and 1.8 and an Abbe number between 20 and 40, and is mainly used to correct chromatic aberration and other types of aberrations.

[0057] In one embodiment, the first lens 1 comprises a convex lens with positive refractive power. The material of the first lens 1 is crown glass. The refractive index of the first lens 1 is between 1.6 and 1.8. The Abbe number of the first lens 1 is between 40 and 60.

[0058] In this embodiment, the first lens element 1 comprises a convex lens with positive optical power, made of crown glass. Crown glass was chosen for its excellent transmittance and minimal dispersion in the visible light band, which helps reduce chromatic aberration. The refractive index of the first lens element 1 is set between 1.6 and 1.8, and its Abbe number is between 40 and 60. This combination effectively controls spherical aberration and provides sufficient correction to balance other aberrations, such as coma and distortion.

[0059] In one embodiment, the second lens 2 includes a concave lens with negative optical power. The material of the second lens 2 is heavy flint glass. The refractive index of the second lens 2 is greater than 1.7, and the Abbe number of the second lens 2 is greater than 20.

[0060] In this embodiment, the second lens element 2 is a concave lens with negative optical power, made of heavy flint glass, which has a refractive index greater than 1.7 and an Abbe number greater than 20. Heavy flint glass is selected to utilize its high refractive index and relatively low Abbe number to increase the dispersion of the system, thereby enhancing the separation of different colored light and thus better correcting chromatic aberration.

[0061] In one embodiment, the third lens 3 comprises a convex lens with positive refractive power. The material of the third lens 3 is crown glass. The refractive index of the third lens 3 is between 1.2 and 1.7. The Abbe number of the third lens 3 is greater than 40.

[0062] In this embodiment, the third lens 3 is designed to further optimize the aberration correction in the system, especially chromatic aberration, while maintaining good imaging quality.

[0063] In one embodiment, the fourth lens 4 comprises a convex lens with positive refractive power. The material of the fourth lens 4 is crown glass. The refractive index of the fourth lens 4 is between 1.5 and 1.7. The Abbe number of the fourth lens 4 is between 40 and 60.

[0064] In this embodiment, the main function of the fourth lens 4 is to help adjust the total length of the system without sacrificing optical performance, and to work together with the first three lenses to ensure the imaging quality of the entire system.

[0065] In one embodiment, the fifth lens element 5 includes a concave lens with negative optical power. The material of the fifth lens element 5 is heavy flint glass. The refractive index of the fifth lens element 5 is between 1.6 and 1.8. The Abbe number of the fifth lens element 5 is between 20 and 40.

[0066] In this embodiment, the fifth lens 5 is used for final aberration correction, especially chromatic aberration and field curvature, and to control the angle of light emitted from the lens to make it suitable for projection applications.

[0067] In one embodiment, the optical distance between the first lens 1 and the second lens 2 is 0.5 mm, and the optical distance between the second lens 2 and the third lens 3 is 3.1 mm.

[0068] In one embodiment, the optical distance between the third lens 3 and the fourth lens 4 is 0.8 mm, and the optical distance between the fourth lens 4 and the fifth lens 5 is 1.6 mm.

[0069] In one embodiment, the optical distance between the fifth lens element 5 and the image plane is 1.6 mm.

[0070] The above optical spacing is intended to ensure optimal imaging performance and compact structural size.

[0071] In this embodiment, through the above-mentioned architecture and material combination, this embodiment achieves a large aperture of F number 2, which means that brighter images can be obtained under low light conditions. In addition, the full field of view > ±15° and MTF > 0.3@128lp / mm indicate that the system can provide high resolution and contrast over a wide viewing angle, which is critical for automotive light projection lenses. The back focus to focal length ratio BFL / EFL < 0.3, and the total length to focal length ratio TTL / EFL < 0.7, these two parameters reflect that the system can effectively shorten the overall length, making the design more lightweight, which not only helps save space but also reduces weight, which is particularly important for vehicle-mounted equipment.

[0072] This embodiment uses a structure composed of 5 spherical glass lenses, which not only ensures a high MTF value (>0.3@128lp / mm), but also provides excellent resolution and contrast throughout the entire field of view, and maintains good imaging effects even at a large field of view of ±15°. The distortion within the entire field of view is controlled within 1%, thanks to the carefully designed optical path and reasonable material selection, which makes the imaging distortion extremely small and suitable for precision measurement and detection tasks. The red-green and blue-green differences are both controlled within 2μm, indicating that this lens has excellent color reproduction capabilities, which is particularly important for applications that require accurate color information. The length of the entire optical system is only about 11mm, which not only reduces space occupancy, but also reduces manufacturing costs, while also facilitating integration into various devices. Although there is no special emphasis on temperature characteristics, the selected materials and structural design ensure stable performance under different ambient temperatures and adapt to relatively harsh working conditions.

[0073] See also Figures 2 to 8 ,from Figure 4 As can be seen from the field curvature and distortion graphs, the lens maintains extremely low distortion (less than 1%) across the entire field of view. This means the lens can provide imaging results very close to true-to-scale, making it particularly suitable for distortion-sensitive applications such as precision measurement or high-quality photography.

[0074] pass Figure 3 As can be seen from the ray fan diagram, aberrations such as spherical aberration and chromatic aberration are effectively suppressed throughout the entire field of view. This demonstrates that the advanced optical correction technology used in the lens design ensures high clarity and color accuracy even to the edges of the image.

[0075] in accordance with Figure 5 As shown in the figure, both red-green and blue-green color differences are controlled within 2 microns. This level of chromatic aberration control means that even in complex lighting conditions, the lens can reduce color fringing and improve the overall image quality.

[0076] from Figure 6 、 Figure 7 and Figure 8 The light transfer function graphs at different temperatures (25°C, 85°C, and 105°C) show that the lens maintains stable optical performance over a wide operating temperature range. This is particularly important for equipment that needs to operate in extreme environments, such as outdoor surveillance systems or industrial inspection equipment.

[0077] In summary, the lens in this embodiment offers exceptional distortion control, excellent aberration correction, sophisticated chromatic aberration management, and excellent environmental adaptability. These features make it ideal for professional applications with stringent requirements for image quality and stability.

[0078] The above-mentioned large aperture industrial vision inspection lens applied to the self-closing loop of car lights, by designing a large aperture combination in the lens system, adopting the first, third and fourth lenses 4 as positive focal length lenses, and the second and fifth lenses 5 as negative focal length lenses, can realize effective collection and focusing of light, thereby increasing the aperture size; the configuration of positive and negative focal length lenses optimizes the propagation path of light, so that the system can reduce the size of the optical structure while ensuring optical performance, achieving a compact design; reasonable lens material and optical spacing design enable the lens to maintain stable optical performance at different ambient temperatures; ultimately achieving higher light collection capability, smaller lens size and good temperature adaptability.

[0079] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A large aperture industrial vision inspection lens for self-closing loops of vehicle lights, characterized by: include: A first lens, a second lens, a third lens, a fourth lens and a fifth lens are arranged in sequence from the object side to the image side along the optical axis; wherein, the first lens, the third lens and the fourth lens respectively have positive optical focal length; the second lens and the fifth lens respectively have negative optical focal length; the number of lenses with optical focal length in the lens is five; the object side surface of the first lens is convex, and the image side surface is convex; the object side surface of the second lens is concave, and the image side surface is concave; the object side surface and the image side surface of the third lens are respectively convex; the object side surface of the fourth lens is convex, and the image side surface is concave; the object side surface and the image side surface of the fifth lens are respectively concave; the optical spacing between the first lens and the second lens is 0.5 mm, and the optical spacing between the second lens and the third lens is 3.1 mm.

2. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: A system stop is provided between the second lens and the third lens; and a vignetting stop is provided on a surface of the second lens close to the first lens.

3. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: The material of the first lens is crown glass, the refractive index of the first lens is between 1.6 and 1.8, and the Abbe number of the first lens is between 40 and 60.

4. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: The material of the second lens is heavy flint glass, the refractive index of the second lens is greater than 1.7, and the Abbe number of the second lens is greater than 20.

5. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: The material of the third lens is crown glass, the refractive index of the third lens is between 1.2 and 1.7, and the Abbe number of the third lens is greater than 40.

6. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: The fourth lens is made of crown glass, has a refractive index between 1.5 and 1.7, and has an Abbe number between 40 and 60.

7. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: The material of the fifth lens is heavy flint glass, the refractive index of the fifth lens is between 1.6 and 1.8, and the Abbe number of the fifth lens is between 20 and 40.

8. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: An optical distance between the third lens and the fourth lens is 0.8 mm, and an optical distance between the fourth lens and the fifth lens is 1.6 mm.

9. The large aperture industrial vision inspection lens for a self-closing loop of a vehicle lamp according to claim 1, characterized in that: The optical distance between the fifth lens and the image plane is 1.6 mm.

Images