An industrial lens, optical lens module and vision system

Abstract

Embodiments of the present application provide an industrial lens, an optical lens module and a vision system; wherein the industrial lens comprises, along an optical axis from an object side to an image side, a first lens group, a diaphragm and a second lens group in sequence; the first lens group comprises a first lens with negative refractive power, a second lens and a third lens, a fourth lens with positive refractive power, and a first cemented lens group composed of a fifth lens and a sixth lens, and a second cemented lens group composed of a seventh lens and an eighth lens; the second lens group comprises a third cemented lens group composed of a ninth lens and a tenth lens, an eleventh lens with positive refractive power and a twelfth lens; wherein the first lens to the twelfth lens are all spherical glass lenses.

Description

Technical Field

[0001] This application relates to the field of optical lens design technology, specifically to an industrial lens, an optical lens module including the industrial lens, and a vision system including the optical lens module, which is particularly suitable for application scenarios such as outdoor monitoring and industrial infrared detection that require large target area, high pixel count, short focal length, and day and night confocal performance. Background Technology

[0002] With the rapid development of security monitoring and industrial inspection technologies, increasingly higher demands are being placed on the core imaging component—the lens. An ideal outdoor monitoring or industrial inspection lens needs to have a short focal length to obtain a wide field of view, while also being compatible with high-pixel sensors to capture details.

[0003] Currently, lenses adapted to 1.0-inch and larger target surface chips often require complex optical structures to correct aberrations, especially distortion and field curvature. If the lens is further required to have good imaging performance in both the visible light (e.g., 450nm~700nm) and near-infrared (e.g., 850nm) bands, i.e., to achieve "day and night confocal" and avoid image blurring caused by focus shift during day and night switching, expensive special low-dispersion glass or aspherical lenses are usually required. This greatly increases the manufacturing cost and process complexity of the lens, making it difficult to promote its large-scale application in the industrial field. Summary of the Invention

[0004] The purpose of this application is to provide an industrial lens, an optical lens module, and a vision system to solve the problems of high cost and difficulty in achieving day and night confocal performance in existing large-area short-focal-length lenses.

[0005] In a first aspect, embodiments of this application provide an industrial lens, which includes a first lens group, an aperture stop, and a second lens group sequentially along the optical axis from the object side to the image side. The first lens group includes: The first lens has negative optical power; The second lens has negative optical power; The third lens has negative optical power; The fourth lens has positive optical power; A first cemented lens group consisting of a fifth lens and a sixth lens, wherein the fifth lens has negative optical power and the sixth lens has positive optical power; A second cemented lens group consisting of a seventh lens and an eighth lens, wherein the seventh lens has positive optical power and the eighth lens has negative optical power; The second lens group includes: A third cemented lens group consisting of a ninth lens and a tenth lens, wherein the ninth lens has negative optical power and the tenth lens has positive optical power; The eleventh lens has positive optical power; The twelfth lens has positive optical power; Among them, the first lens to the twelfth lens are all spherical glass lenses.

[0006] Optionally, the first lens, the second lens, and the third lens are all meniscus negative lenses; The fourth lens is a meniscus lens; The fifth lens is a biconcave negative lens, and the sixth lens is a biconvex positive lens; The seventh lens is a biconvex positive lens, and the eighth lens is a biconcave negative lens; The ninth lens is a biconcave negative lens, and the tenth lens is a biconvex positive lens; The eleventh lens is a meniscus lens; The twelfth lens is a biconvex positive lens.

[0007] Optionally, the industrial lens satisfies the relationship: 0.2≤Fa / Fb≤0.6, where Fa is the combined focal length of the first lens group and Fb is the combined focal length of the second lens group.

[0008] Optionally, the industrial lens satisfies the following relationship: -2.8≤F1 / F≤-1.5; -7.3≤F2 / F≤-4; -5.5≤F3 / F≤-4.6; 3.3≤F4 / F≤5; 2.2≤F11 / F≤2.7; 2≤F12 / F≤2.3; Wherein, F is the effective focal length of the industrial lens, and F1, F2, F3, F4, F11, and F12 are the effective focal lengths of the first lens, the second lens, the third lens, the fourth lens, the eleventh lens, and the twelfth lens, respectively.

[0009] Optionally, the industrial lens satisfies the following relationship: -4.8≤F5 / F6≤-3.1; -0.7≤F7 / F8≤-0.4; -0.5≤F9 / F10≤-0.2; Wherein, F5 and F6 are the effective focal lengths of the fifth lens and the sixth lens, respectively; F7 and F8 are the effective focal lengths of the seventh lens and the eighth lens, respectively; and F9 and F10 are the effective focal lengths of the ninth lens and the tenth lens, respectively.

[0010] Optionally, the lenses in the first lens group satisfy the following conditions: The object-side surface curvature radius R1 of the first lens satisfies 26mm < R1 < 34mm, and the image-side surface curvature radius R2 satisfies 9mm < R2 < 15mm. The object-side surface curvature radius R1 of the second lens satisfies 49mm < R1 < 783mm, and the image-side surface curvature radius R2 satisfies 16mm < R2 < 43mm. The object-side surface curvature radius R1 of the third lens satisfies -329mm < R1 < -38mm, and the image-side surface curvature radius R2 satisfies 30mm < R2 < 218mm. The object-side surface curvature radius R1 of the fourth lens satisfies 33mm < R1 < 45mm, and the image-side surface curvature radius R2 satisfies -128mm < R2 < 1969mm.

[0011] Optionally, the object-side surface curvature radius R1 of the fifth lens satisfies -37mm < R1 < -24mm, and the image-side surface curvature radius R2 satisfies 22mm < R2 < 27mm. The object-side surface curvature radius R1 of the sixth lens satisfies 22mm < R1 < 27mm, and the image-side surface curvature radius R2 satisfies -26mm < R2 < -23mm. The object-side surface curvature radius R1 of the seventh lens satisfies 11mm < R1 < 13mm, and the image-side surface curvature radius R2 satisfies -69mm < R2 < -29mm. The object-side surface curvature radius R1 of the eighth lens satisfies -69mm < R1 < -29mm, and the image-side surface curvature radius R2 satisfies 55mm < R2 < 67mm.

[0012] Optionally, the lenses in the second lens group satisfy the following conditions: The object-side surface curvature radius R1 of the ninth lens satisfies -8mm < R1 < -6mm, and the image-side surface curvature radius R2 satisfies 15mm < R2 < 18mm. The object-side surface curvature radius R1 of the tenth lens satisfies 15mm < R1 < 18mm, and the image-side surface curvature radius R2 satisfies -12mm < R2 < -8mm. The object-side surface curvature radius R1 of the eleventh lens satisfies -622mm < R1 < -46mm, and the image-side surface curvature radius R2 satisfies -26mm < R2 < -20mm. The object-side surface curvature radius R1 of the twelfth lens satisfies 27mm < R1 < 29mm, and the image-side surface curvature radius R2 satisfies -61mm < R2 < -53mm.

[0013] Optionally, the total optical length (TTL) of the industrial lens satisfies: TTL≤70mm; The effective focal length F of the industrial lens satisfies: F≤16mm.

[0014] Optionally, the working distance WD of the industrial lens is WD≥1000mm, where WD is the axial distance from the object-side surface of the first lens of the industrial lens to the object plane where the observed object is located. The industrial lens can achieve day and night confocal imaging in the visible light and near-infrared bands.

[0015] Secondly, embodiments of this application provide an optical lens module, the optical lens module comprising: The industrial lens described in the first aspect; A photosensitive chip disposed on the image side of the industrial lens; and, A glass plate is disposed between the industrial lens and the photosensitive chip.

[0016] Thirdly, embodiments of this application provide a vision system, the vision system comprising: The optical lens module as described in the second aspect.

[0017] One technical effect of this application is: The industrial lens provided in this application embodiment has a first lens group, an aperture stop, and a second lens group arranged sequentially along the optical axis from the object side to the image side. The first lens group includes a first lens to a third lens with negative optical power, a fourth lens with positive optical power, a first cemented lens group composed of a fifth lens and a sixth lens, and a second cemented lens group composed of a seventh lens and an eighth lens. The second lens group includes a third cemented lens group composed of a ninth lens and a tenth lens, an eleventh lens and a twelfth lens with positive optical power, and all twelve lenses are spherical glass lenses. Thus, without the need to use aspherical lenses or special low-dispersion glass materials, the lens effectively corrects the distortion and field curvature aberrations that are prone to occur in short-focal-length, large-surface optical lenses through reasonable optical power distribution and cemented lens group design. This achieves low-cost manufacturing using all-glass materials and has good process consistency and mass production capability.

[0018] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0020] Figure 1One of the schematic diagrams of the optical structure of an industrial lens provided in the embodiments of this application; Figure 2 The optical path diagram of the industrial lens provided in the embodiments of this application; Figure 3 One of the MTF diagrams of an industrial lens provided in the embodiments of this application; Figure 4 One of the field curvature and distortion diagrams of an industrial lens provided in the embodiments of this application; Figure 5 A second schematic diagram of the optical structure of an industrial lens provided in an embodiment of this application; Figure 6 This is the second optical path diagram of an industrial lens provided in the embodiments of this application; Figure 7 The second MTF diagram of an industrial lens provided in the embodiments of this application; Figure 8 The second example of field curvature and distortion diagrams of an industrial lens provided in the embodiments of this application.

[0021] Explanation of reference numerals in the attached figures: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Ninth lens; 10. Tenth lens; 11. Eleventh lens; 12. Twelfth lens; 13. Glass plate; 14. Aperture; 15. Photosensitive chip. Detailed Implementation

[0022] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0023] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0024] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0025] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0026] 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 discussed further in subsequent figures.

[0027] The industrial lens, optical lens module, and vision system provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0028] According to one aspect of this application, an industrial lens is provided, see [link to application]. Figure 1 and Figure 2 The system comprises, from the object side to the image side, a first lens group, an aperture stop 14, and a second lens group along the optical axis. The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8 arranged sequentially from the object side to the image side along the optical axis. The first lens 1, the second lens 2, and the third lens 3 all have negative optical power, while the fourth lens 4 has positive optical power. The fifth lens 5 and the sixth lens 6 form a first cemented lens group, with the fifth lens 5 having negative optical power and the sixth lens 6 having positive optical power. The seventh lens 7 and the eighth lens 8 form a second cemented lens group, with the seventh lens 7 having positive optical power and the eighth lens 8 having negative optical power. The second lens group includes a ninth lens 9, a tenth lens 10, an eleventh lens 11, and a twelfth lens 12 arranged sequentially from the object side to the image side along the optical axis; the ninth lens 9 and the tenth lens 10 form a third cemented lens group, and the ninth lens 9 has negative optical power, the tenth lens 10 has positive optical power, the eleventh lens 11 has positive optical power, and the twelfth lens 12 has positive optical power. All lenses 1 through 12 are spherical glass lenses.

[0029] The industrial lens provided in this application embodiment has an optical structure and optical path, please refer to [the relevant documentation]. Figure 1 and Figure 2 It should be noted that, Figure 1 The optical structure shown is a reverse light path design, and its actual light path is as follows: Figure 2 As shown: Light enters from the image side, passes sequentially through the twelfth lens 12, the eleventh lens 11, the tenth lens 10, the ninth lens 9, the aperture 14, the eighth lens 8, the seventh lens 7, the sixth lens 6, the fifth lens 5, the fourth lens 4, the third lens 3, the second lens 2, and the first lens 1 before exiting to the object side. The industrial lens provided in the embodiments of this application will be described below along the actual light incident direction.

[0030] See Figure 1 and Figure 2The coordination of the rear positive power lens group (the twelfth lens 12 and the eleventh lens 11): In the actual optical path, light first enters the twelfth lens 12 and the eleventh lens 11, which have positive power. These two positive lenses work together to undertake the main light-converging function of the industrial lens, effectively converging large-angle light from a large target surface image sensor (e.g., with a diagonal size > 1.0 inch), smoothly transitioning it to subsequent lens groups, and providing a suitable main ray incident angle for the entire industrial lens, thereby ensuring the uniformity of image plane illumination and the relative illumination of the edge field of view.

[0031] The calibration and alignment of the third cemented lens group (which consists of the cemented ninth lens 9 and the tenth lens 10): In the actual optical path, see... Figure 2 The light continues to pass sequentially through the tenth lens 10 and the ninth lens 9. The third cemented lens group, composed of the tenth lens 10 with positive optical power and the ninth lens 9 with negative optical power, effectively corrects for axial chromatic aberration and magnification chromatic aberration in the converging light path by utilizing the difference in refractive index and Abbe number between the positive and negative lenses. Furthermore, by matching the curvature of the cemented surfaces, it can further reduce higher-order spherical aberration, which is beneficial to improving image quality.

[0032] Setting of aperture 14: Aperture 14 is positioned between the ninth lens 9 and the eighth lens 8, see [reference needed]. Figure 1 and Figure 2 In actual optical paths, see [reference needed]. Figure 2 The light rays pass through the tenth lens 10 and the ninth lens 9 in sequence before being projected onto the aperture 14, and then enter the eighth lens 8.

[0033] The balanced arrangement of the second cemented lens group (composed of the seventh lens 7 and the eighth lens 8 cemented together): In the actual optical path, light rays pass through the aperture 14 and are projected onto the eighth lens 8, and then enter the seventh lens 7. The second cemented lens group, composed of the eighth lens 8 with negative optical power and the seventh lens 7 with positive optical power, is located after the aperture 14. This second cemented lens group, through its alternating positive and negative optical power design with the aforementioned third cemented lens group, can effectively correct optical problems such as field curvature introduced by the large target surface and short focal length design, thereby ensuring the flatness of the image field.

[0034] The optical power coordination of the first cemented lens group (composed of the fifth lens 5 and the sixth lens 6 cemented together): In the actual optical path, light rays pass through the sixth lens 6 and the fifth lens 5 sequentially. The first cemented lens group, formed by cementing the sixth lens 6, which has positive optical power, and the fifth lens 5, which has negative optical power, further disperses the optical power of the entire industrial lens, reduces the optical power load on each lens, thereby reducing spherical aberration and chromatic aberration, and helps to shorten the overall optical length, achieving a compact optical structure.

[0035] The coordination of the front-end positive and negative lens groups (fourth lens 4, third lens 3, second lens 2, and first lens 1): In the actual optical path, light rays pass through the fourth lens 4, third lens 3, second lens 2, and first lens 1 sequentially. The fourth lens 4, with its positive optical power, and the third lens 3, second lens 2, and first lens 1, with their negative optical power, are arranged in sequence, forming a positive-negative-negative-negative optical power distribution pattern. This arrangement, while converging the incident light rays and increasing the field of view, effectively suppresses distortion and field curvature of wide-angle lenses through the complementarity of positive and negative optical power, ensuring the imaging quality of the edge field of view.

[0036] Through the coordinated operation of the above-mentioned multiple lens groups and cemented lens groups, the embodiments of this application achieve at least the following technical effects.

[0037] In terms of cost: All 12 lenses in the industrial lens of this application embodiment can be spherical glass lenses, eliminating the need for aspherical processing technology and expensive ultra-low dispersion or special glass materials, thereby reducing material and processing costs.

[0038] In terms of structural compactness: Through reasonable optical power distribution and cemented lens design, the structure of 12 lenses can still achieve an ultra-short focal length design with a total optical length of ≤70mm and a focal length of f≤16mm, which can meet the installation requirements of miniaturized outdoor monitoring equipment.

[0039] In terms of aberration correction: the structure of three cemented lens groups and reasonable distribution of positive and negative optical power effectively corrects the distortion (maximum distortion ≤10%), field curvature, spherical aberration and chromatic aberration that are prone to occur in short focal length large target surface lenses, ensuring image clarity across the entire field of view.

[0040] Furthermore, the industrial lens of this application can cover image sensors with a diagonal size ≥ 1.0 inch, supporting resolution requirements of 24 megapixels and above, meeting the high detail capture requirements of industrial inspection and security monitoring. Moreover, through the Abbe number and refractive index matching design of the positive and negative lens materials in each cemented lens group, the focal plane offset of the industrial lens of this application is controlled within the depth of field range in the visible light band (e.g., 450nm~700nm) and the near-infrared band (e.g., 850nm), eliminating the need for refocusing during day-night switching and effectively avoiding image blur.

[0041] The industrial lens of this application maintains excellent imaging performance within a working distance range of 1000mm to infinity, making it highly suitable for applications such as outdoor monitoring and long-distance industrial inspection.

[0042] In summary, this application, through the aforementioned specific lens combination structure, achieves multiple performance requirements such as compact structure, large target surface, short focal length, low aberration, and day and night confocality under the conditions of low cost and all-glass spherical lens. It solves the technical problems of high cost, difficulty in achieving day and night confocality, and large-scale mass production of high-performance short focal length lenses in the prior art.

[0043] See some examples in this application. Figure 1 and Figure 2 The surface shapes of the lenses in the first lens group are as follows: the first lens 1, the second lens 2, and the third lens 3 are all meniscus negative lenses; the fourth lens 4 is a meniscus positive lens; the fifth lens 5 is a biconcave negative lens; the sixth lens 6 is a biconvex positive lens; the seventh lens 7 is a biconvex positive lens; and the eighth lens 8 is a biconcave negative lens. The surface shapes of the lenses in the second lens group are as follows: the ninth lens 9 is a biconcave negative lens; the tenth lens 10 is a biconvex positive lens; the eleventh lens 11 is a meniscus positive lens; and the twelfth lens 12 is a biconvex positive lens.

[0044] In this example of the application, see Figure 1 and Figure 2 The surface shape of each lens was specifically designed based on its position in the optical path and the optical power it is responsible for.

[0045] Specifically, in the second lens group, the twelfth lens 12 is a biconvex positive lens. In the actual optical path, light rays first enter the twelfth lens 12 to converge the light rays and provide a suitable principal ray angle for subsequent lens groups. The eleventh lens 11 is a meniscus positive lens, whose meniscus shape helps to smooth the light transition and maintain uniform illumination on the image plane. The ninth lens 9 is a biconcave negative lens, and the tenth lens 10 is a biconvex positive lens. The two are cemented together to form a third cemented lens group. Light rays pass through the tenth lens 10 and the ninth lens 9 in sequence. The matching of the biconcave and biconvex surfaces can effectively correct axial chromatic aberration and magnification chromatic aberration.

[0046] Light enters the first lens group after passing through the aperture 14. In the first lens group, the seventh lens 7 is a biconvex positive lens, and the eighth lens 8 is a biconcave negative lens; the two are cemented together to form a second cemented lens group. This cemented group utilizes the positive and negative optical power of the biconvex and biconcave surfaces to effectively balance the optical power distribution of the system and is particularly beneficial for correcting field curvature. The fifth lens 5 is a biconcave negative lens, and the sixth lens 6 is a biconvex positive lens; the two are cemented together to form a first cemented lens group. This cemented group also significantly reduces spherical aberration and chromatic aberration while dispersing the optical power of the system through the combination of biconcave and biconvex surfaces. The fourth lens 4 is a meniscus positive lens, used to undertake the main converging function in the optical path and further balance off-axis aberrations. The first lens 1, the second lens 2, and the third lens 3 are all meniscus negative lenses. Light passes through the third lens 3, the second lens 2, and the first lens 1 in sequence before exiting to the object side. Each meniscus shape is beneficial for receiving large-angle light while gradually converging the beam and effectively controlling astigmatism and distortion.

[0047] By rationally selecting and combining the above-mentioned lens surface types, the industrial lens of this application embodiment can achieve excellent optical imaging performance under the condition of a global surface glass lens.

[0048] In some examples of this application, the industrial lens satisfies the relationship: 0.2≤Fa / Fb≤0.6, where Fa is the combined focal length of the first lens group and Fb is the combined focal length of the second lens group.

[0049] The relationship in this example constrains the ratio of the combined focal length of the first lens group and the second lens group. By controlling Fa / Fb between 0.2 and 0.6, the optical power can be reasonably distributed on both sides of the aperture stop 14.

[0050] When Fa / Fb satisfies the above relationship, this allocation method is beneficial for balancing the aberrations of the entire industrial lens, especially for correcting optical distortion and field curvature. This reasonable focal length ratio can also shorten the overall optical length of the industrial lens, enabling a compact design and ensuring good imaging performance even under conditions of large target area and short focal length.

[0051] In some examples of this application, the industrial lens satisfies the following relationship: -2.8≤F1 / F≤-1.5; -7.3≤F2 / F≤-4; -5.5≤F3 / F≤-4.6; 3.3≤F4 / F≤5; 2.2≤F11 / F≤2.7; 2≤F12 / F≤2.3; Wherein, F is the effective focal length of the industrial lens, and F1, F2, F3, F4, F11, and F12 are the effective focal lengths of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the eleventh lens 11, and the twelfth lens 12, respectively.

[0052] The relation in this example constrains the range of ratios between the effective focal lengths of the six individual lenses and the overall effective focal length of the industrial lens.

[0053] In actual optical paths, see Figure 2 The light first enters through the twelfth lens 12 and the eleventh lens 11. Both the twelfth lens 12 and the eleventh lens 11 are positive power lenses, and the ratio of their respective effective focal lengths to the effective focal length F of the industrial lens is positive. These two positive lenses work together at the front end to converge the light. This configuration provides sufficient positive power to shorten the total optical length (TTL) of the industrial lens, while avoiding excessive concentration of power on a single lens, thus reducing the risk of introducing higher-order aberrations.

[0054] Subsequently, the light passes through the fourth lens 4. The fourth lens 4 is a positive focal length lens with a positive effective focal length ratio that is larger than that of the eleventh lens 11 and the twelfth lens 12. The fourth lens 4 bears the main positive focal length in the entire industrial lens and is used to smoothly transition the light converged by the front lens group to the subsequent lenses.

[0055] Finally, the light rays pass sequentially through the third lens 3, the second lens 2, and the first lens 1 before exiting to the object side. The first lens 1, the second lens 2, and the third lens 3 are all negative power lenses, with negative and different focal length ratios. This design facilitates the gradual expansion of large-angle light rays before their emission and shares the burden of distortion and astigmatism correction, ensuring image quality at the edges of the field of view.

[0056] By controlling the focal length ratio of the above six lenses within the appropriate range, it is possible to effectively correct various aberrations such as spherical aberration, chromatic aberration, distortion, and field curvature while ensuring short focal length and large target surface imaging performance, thereby obtaining high-definition image quality.

[0057] In some examples of this application, the industrial lens satisfies the following relationship: -4.8≤F5 / F6≤-3.1; -0.7≤F7 / F8≤-0.4; -0.5≤F9 / F10≤-0.2; Wherein, F5 and F6 are the effective focal lengths of the fifth lens 5 and the sixth lens 6, respectively; F7 and F8 are the effective focal lengths of the seventh lens 7 and the eighth lens 8, respectively; and F9 and F10 are the effective focal lengths of the ninth lens 9 and the tenth lens 10, respectively.

[0058] The relationship in this example constrains the ratio of the effective focal lengths of the positive and negative lenses in the three cemented lens groups. All ratios are negative, indicating that each cemented lens group consists of one positive power lens and one negative power lens.

[0059] For the three cemented lens groups in industrial lenses, see Figure 2 The light first enters the third cemented lens group composed of the ninth lens 9 and the tenth lens 10. The focal length ratio F9 / F10 of the ninth lens 9 and the tenth lens 10 is -0.5≤F9 / F10≤-0.2. This parameter design facilitates effective convergence of light upon incident light, while simultaneously using the difference in refractive index and Abbe number between the positive and negative lenses to correct chromatic aberration.

[0060] See Figure 2 After passing through the aperture stop 14, the light enters the second cemented lens group composed of the eighth lens 8 and the seventh lens 7. The focal length ratio F7 / F8 of the seventh lens 7 and the eighth lens 8 is -0.7≤F7 / F8≤-0.4. This parameter configuration allows the positive and negative lenses to cooperate with each other in the optical path, which is beneficial for correcting field curvature and balancing lens aberrations.

[0061] Please continue reading Figure 2 Subsequently, the light enters the first cemented lens group composed of the sixth lens 6 and the fifth lens 5. The focal length ratio of the fifth lens 5 to the sixth lens 6, F5 / F6, is -5.2 ≤ F5 / F6 ≤ -4.2. This parameter configuration is beneficial for further diverging the light and dispersing the lens's optical power, thereby reducing spherical aberration and chromatic aberration.

[0062] The three cemented lens groups each undertake different aberration correction tasks in the optical path, working together to improve the overall imaging quality of the industrial lens.

[0063] In some examples of this application, the lenses in the first lens group satisfy the following conditions: The object-side surface curvature radius R1 of the first lens 1 satisfies 26mm < R1 < 34mm, and the image-side surface curvature radius R2 satisfies 9mm < R2 < 15mm. The object-side surface curvature radius R1 of the second lens 2 satisfies 49mm < R1 < 783mm, and the image-side surface curvature radius R2 satisfies 16mm < R2 < 43mm. The object-side surface curvature radius R1 of the third lens 3 satisfies -329mm < R1 < -38mm, and the image-side surface curvature radius R2 satisfies 30mm < R2 < 218mm. The object-side surface curvature radius R1 of the fourth lens 4 satisfies 33mm < R1 < 45mm, and the image-side surface curvature radius R2 satisfies -128mm < R2 < 1969mm.

[0064] In some examples of this application, the object-side surface curvature radius R1 of the fifth lens 5 satisfies -37mm < R1 < -24mm, and the image-side surface curvature radius R2 satisfies 22mm < R2 < 27mm. The object-side surface curvature radius R1 of the sixth lens 6 satisfies 22mm < R1 < 27mm, and the image-side surface curvature radius R2 satisfies -26mm < R2 < -23mm. The object-side surface curvature radius R1 of the seventh lens 7 satisfies 11mm < R1 < 13mm, and the image-side surface curvature radius R2 satisfies -69mm < R2 < -29mm. The object-side surface curvature radius R1 of the eighth lens 8 satisfies -69mm < R1 < -29mm, and the image-side surface curvature radius R2 satisfies 55mm < R2 < 67mm.

[0065] In the two examples above in this application, the eight lenses that make up the first lens group satisfy a specific radius of curvature.

[0066] In the actual optical path, light rays first enter the eighth lens 8 after passing through the aperture 14. The object-side surface curvature radius R1 of the eighth lens 8 satisfies -69mm < R1 < -29mm, and the image-side surface curvature radius R2 satisfies 55mm < R2 < 67mm. Subsequently, light rays enter the seventh lens 7, whose object-side surface curvature radius R1 satisfies 11mm < R1 < 13mm, and its image-side surface curvature radius R2 satisfies -69mm < R2 < -29mm. The seventh lens 7 and the eighth lens 8 form a second cemented lens group. The matching of the above curvature radii is beneficial for correcting field curvature and balancing lens aberrations.

[0067] Subsequently, light is incident on the sixth lens 6, whose object-side surface curvature radius R1 satisfies 22mm < R1 < 27mm, and whose image-side surface curvature radius R2 satisfies -26mm < R2 < -23mm. Then, it is incident on the fifth lens 5, whose object-side surface curvature radius R1 satisfies -37mm < R1 < -24mm, and whose image-side surface curvature radius R2 satisfies 22mm < R2 < 27mm. The fifth lens 5 and the sixth lens 6 form the first cemented lens group. The aforementioned matching of curvature radii helps to disperse optical power and reduce spherical aberration and chromatic aberration of the lens.

[0068] The light continues its journey, passing through the fourth lens 4. The object-side surface curvature radius R1 satisfies 33mm < R1 < 45mm, and the image-side surface curvature radius R2 satisfies -128mm < R2 < 1969mm (i.e., the image-side surface can be nearly flat). This fourth lens 4 also has a relatively thick center thickness, which, combined with its large radius of curvature, enables it to handle the main positive optical power, ensuring a smooth transition of the converged light to subsequent lens elements.

[0069] Finally, the light rays pass sequentially through the third lens 3, the second lens 2, and the first lens 1 before exiting to the object side. The object-side surface curvature radius R1 of the third lens 3 satisfies -329mm < R1 < -38mm, and the image-side surface curvature radius R2 satisfies 30mm < R2 < 218mm. The object-side surface curvature radius R1 of the second lens 2 satisfies 49mm < R1 < 783mm, and the image-side surface curvature radius R2 satisfies 16mm < R2 < 43mm. The object-side surface curvature radius R1 of the first lens 1 satisfies 26mm < R1 < 34mm, and the image-side surface curvature radius R2 satisfies 9mm < R2 < 15mm. These three negative lenses suppress distortion and astigmatism, ensuring image quality at the edges of the field of view.

[0070] By optimizing the curvature radius of each lens within the above parameter range, a reasonable distribution of optical power can be achieved, ensuring that the industrial lens has excellent aberration correction capabilities within a compact structure.

[0071] In some examples of this application, the lenses in the second lens group satisfy the following conditions: The object-side surface curvature radius R1 of the ninth lens 9 satisfies -8mm < R1 < -6mm, and the image-side surface curvature radius R2 satisfies 15mm < R2 < 18mm. The object-side surface curvature radius R1 of the tenth lens 10 satisfies 15mm < R1 < 18mm, and the image-side surface curvature radius R2 satisfies -12mm < R2 < -8mm. The object-side surface curvature radius R1 of the eleventh lens 11 satisfies -622mm < R1 < -46mm, and the image-side surface curvature radius R2 satisfies -26mm < R2 < -20mm. The object-side surface curvature radius R1 of the twelfth lens 12 satisfies 27mm < R1 < 29mm, and the image-side surface curvature radius R2 satisfies -61mm < R2 < -53mm.

[0072] In this example of the application, the four lenses that make up the second lens group satisfy a specific radius of curvature.

[0073] In the actual optical path, the light rays first enter the twelfth lens 12. The object-side surface curvature radius R1 of the twelfth lens 12 satisfies 27mm < R1 < 29mm, and the image-side surface curvature radius R2 satisfies -61mm < R2 < -53mm. The twelfth lens 12 is a biconvex positive lens, and its curvature radius design enables it to effectively converge the incident light rays and provide a suitable principal ray angle for subsequent lens groups.

[0074] Subsequently, light is incident on the eleventh lens 11. The object-side surface curvature radius R1 of the eleventh lens 11 satisfies -622mm < R1 < -46mm, and the image-side surface curvature radius R2 satisfies -26mm < R2 < -20mm. The eleventh lens 11 is a meniscus positive lens, and its meniscus shape helps to smooth the light transition and maintain uniform illumination on the image plane.

[0075] Next, light is incident on the third cemented lens group composed of the tenth lens 10 and the ninth lens 9. The object-side surface curvature radius R1 of the tenth lens 10 satisfies 15mm < R1 < 18mm, and the image-side surface curvature radius R2 satisfies -12mm < R2 < -8mm. The object-side surface curvature radius R1 of the ninth lens 9 satisfies -8mm < R1 < -6mm, and the image-side surface curvature radius R2 satisfies 15mm < R2 < 18mm. The matching curvature radii of the tenth lens 10 and the ninth lens 9 ensure good adhesion between their cemented surfaces. Utilizing the difference in refractive index and Abbe number between the positive and negative lenses, axial chromatic aberration and magnification chromatic aberration are effectively corrected.

[0076] By optimizing the curvature radius of each lens in the second lens group within the above parameter range, light can be effectively converged and chromatic aberration corrected when incident from the image side, providing good lighting conditions for the subsequent imaging of the first lens group.

[0077] In some examples of this application, the total optical length (TTL) of the industrial lens satisfies: TTL ≤ 70 mm. The effective focal length (F) of the industrial lens satisfies: F ≤ 16 mm.

[0078] With an overall optical length of ≤70mm, the industrial lens features a compact optical structure design that meets the installation space requirements of miniaturized outdoor monitoring equipment and industrial testing instruments.

[0079] An effective focal length of ≤16mm indicates that the industrial lens has ultra-short focal length characteristics, enabling it to obtain a wide field of view at relatively close shooting distances, making it suitable for large-scale monitoring scenarios.

[0080] This application achieves the design goals of a total optical length ≤70mm and a focal length ≤16mm simultaneously by using a structure with 12 lenses, through reasonable distribution of optical power and cemented lens group design, thus taking into account the dual requirements of compact optical structure and ultra-short focal length.

[0081] In some examples of this application, the working distance WD of the industrial lens is WD≥1000mm, where WD is the axial distance from the object-side surface of the first lens 1 of the industrial lens to the object plane where the observed object is located. The industrial lens can achieve day and night confocal imaging in both the visible and near-infrared bands.

[0082] With a working distance ranging from 1000mm to infinity, the industrial lens of this application is suitable for medium- to long-distance observation scenarios, such as outdoor security monitoring and long-distance inspection of industrial production lines. Within this working distance range, the industrial lens can maintain stable imaging performance without the need for repeated focusing.

[0083] Furthermore, the industrial lens can achieve day and night confocal imaging in the visible light band (e.g., 450nm~700nm) and the near-infrared band (e.g., 850nm). Day and night confocal imaging means that when the lens uses visible light for imaging during the day and near-infrared light (with an infrared fill light) for imaging at night, the image plane positions are essentially the same, with the offset controlled within the system's depth of field.

[0084] To achieve this performance, this application employs a matching design between the Abbe number and refractive index of the positive and negative lens materials in each cemented lens assembly, ensuring that light from different wavelengths converges at the same image plane position after passing through the industrial lens. This allows the monitoring system to obtain a clear image without needing to readjust the lens focus when switching between day and night modes (e.g., turning off the infrared filter during the day and switching to infrared mode at night), effectively avoiding image blurring caused by focus shift.

[0085] By combining the aforementioned working distance with day and night confocal performance, the industrial lens provided in this application can meet the needs of 24-hour uninterrupted monitoring and maintain excellent imaging quality throughout the range from 1000mm to infinity.

[0086] The optical lens of this application is described below through Embodiment 1 and Embodiment 2.

[0087] Example 1 The industrial lens provided in this embodiment 1 has the following optical structure: Figure 1 As shown. The industrial lens, along the optical path (from image side to object side), consists of the following components in sequence: the second lens group, the aperture 14, and the first lens group.

[0088] The second lens group includes a twelfth lens 12, an eleventh lens 11, a tenth lens 10, and a ninth lens 9 arranged sequentially from the image side to the object side. Specifically: the twelfth lens 12 is a biconvex positive lens; the eleventh lens 11 is a meniscus positive lens; the tenth lens 10 is a biconvex positive lens; and the ninth lens 9 is a biconcave negative lens. The ninth lens 9 and the tenth lens 10 are cemented together to form a third cemented lens group.

[0089] The first lens group includes, from image side to object side, an eighth lens 8, a seventh lens 7, a sixth lens 6, a fifth lens 5, a fourth lens 4, a third lens 3, a second lens 2, and a first lens 1. Specifically: the eighth lens 8 is a biconcave negative lens; the seventh lens 7 is a biconvex positive lens; the eighth lens 8 and the seventh lens 7 are cemented together to form a second cemented lens group. The sixth lens 6 is a biconvex positive lens; the fifth lens 5 is a biconcave negative lens; the sixth lens 6 and the fifth lens 5 are cemented together to form a first cemented lens group. The fourth lens 4 is a meniscus positive lens. The third lens 3, the second lens 2, and the first lens 1 are all meniscus negative lenses.

[0090] In this embodiment 1, the relationship between the effective focal length of each lens and the effective focal length F of the industrial lens is as follows: The ratio of the effective focal length F1 to F of the first lens 1 satisfies F1 / F = -2.7; The ratio of the effective focal length F2 to F of the second lens 2 satisfies F2 / F = -4.1; The ratio of the effective focal length F3 to F of the third lens 3 satisfies F3 / F = -4.7; The ratio of the effective focal length F4 to F of the fourth lens 4 satisfies F4 / F = 5.1; The ratio of the effective focal length F11 to F of the eleventh lens 11 satisfies F11 / F = 2.3; The ratio of the effective focal length F12 to F of the twelfth lens 12 satisfies F12 / F = 2.1.

[0091] The ratio of the effective focal lengths of the positive and negative lenses in the three cemented lens groups satisfies the following relationship: The focal length ratio of the fifth lens 5 and the sixth lens 6 satisfies F5 / F6 = -4.7; The focal length ratio of the seventh lens 7 and the eighth lens 8 satisfies F7 / F8 = -0.6; The focal length ratio of the ninth lens 9 and the tenth lens 10 satisfies F9 / F10 = -0.3.

[0092] Furthermore, the ratio of the combined focal length Fa of the first lens group to the combined focal length Fb of the second lens group, Fa / Fb, is 0.5.

[0093] The optical parameters of the industrial lens in this embodiment 1 are detailed in Table 1.

[0094] Table 1

[0095] The optical parameters of the industrial lens provided in this embodiment 1 are as follows: Relative aperture: D / f′=1 / 5.6; Half-image height Y = 9.65mm (compatible with 1.2-inch sensor); TTL≤70mm; FNO=5.6; Working distance from 4000mm to infinity; See Figure 3 , MTF@75lp / mm≥0.5, MTF@38lp / mm≥0.7, MTF@150lp / mm≥0.2; See Figure 4 Its optical distortion is <10%; Applicable spectral range: 450nm and 850nm; Resolution: 24 megapixels; Field of view: 2ω = 82.8°; The focal length of the industrial lens is 12mm.

[0096] Example 2 This embodiment 2 provides an industrial lens with the following optical structure: Figure 5 As shown, its optical path diagram is as follows: Figure 6 As shown. This industrial lens is identical to Example 1 in optical architecture, lens composition, materials, lens shape, order, and bonding relationship; that is, it also adopts the same... Figure 1 The optical structure shown consists of twelve spherical optical glass lenses.

[0097] In this embodiment 2, the relationship between the effective focal length of each lens and the effective focal length F of the industrial lens is as follows: The ratio of the effective focal length F1 to F of the first lens 1 satisfies F1 / F = -1.6; The ratio of the effective focal length F2 to F of the second lens 2 satisfies F2 / F = -7.2; The ratio of the effective focal length F3 to F of the third lens 3 satisfies F3 / F = -5.4; The ratio of the effective focal length F4 to F of the fourth lens 4 satisfies F4 / F = 3.4; The ratio of the effective focal length F11 to F of the eleventh lens 11 satisfies F11 / F = 2.6; The ratio of the effective focal length F12 to F of the twelfth lens 12 satisfies F12 / F = 2.2.

[0098] The ratio of the effective focal lengths of the positive and negative lenses in the three cemented lens groups satisfies the following relationship: The focal length ratio of the fifth lens 5 and the sixth lens 6 satisfies F5 / F6 = -3.2; The focal length ratio of the seventh lens 7 and the eighth lens 8 satisfies F7 / F8 = -0.5; The focal length ratio of the ninth lens 9 and the tenth lens 10 satisfies F9 / F10 = -0.4.

[0099] Furthermore, the ratio of the combined focal length Fa of the first lens group to the combined focal length Fb of the second lens group, Fa / Fb, is 0.3.

[0100] The detailed optical design parameters for this embodiment 2 are shown in Table 2.

[0101] Table 2

[0102] The optical parameters of the industrial lens provided in this embodiment 2 are as follows: Relative aperture: D / f′=1 / 5.6; Half-image height Y = 9.65mm (compatible with 1.2-inch sensor); TTL≤70mm; FNO=5.6; Working distance from 4000 to infinity; See Figure 7 , MTF@75lp / mm≥0.5, MTF@38lp / mm≥0.7, MTF@150lp / mm≥0.2; See Figure 8 Its optical distortion is <10%; Applicable spectral range: 450nm and 850nm; Resolution: 24 megapixels; Field of view: 2ω = 82.8°; The focal length of the industrial lens is 12mm.

[0103] According to another aspect of this application, an optical lens module is provided, see [link to application]. Figure 1 The optical lens module includes an industrial lens as described in any of the above examples, a photosensitive chip 15 disposed on the image side of the industrial lens, and a glass plate 13 disposed between the industrial lens and the photosensitive chip 15.

[0104] The photosensitive chip 15 has a diagonal size greater than or equal to 1.0 inch and a pixel count of 24 million or more, which can meet the requirements of high-resolution imaging.

[0105] The glass plate 13 is disposed between the industrial lens and the photosensitive chip 15. The glass plate 13 can serve as protective glass to seal and protect the photosensitive surface of the photosensitive chip 15, preventing external contaminants such as dust and moisture from entering.

[0106] According to another aspect of this application, a vision system is provided, the vision system including the optical lens module as described above.

[0107] In practical applications, this vision system can be integrated into a variety of terminal devices.

[0108] For example, in the field of outdoor security monitoring, this vision system can be applied to high-definition network cameras, infrared PTZ cameras and other equipment, utilizing its ultra-short focal length, large target surface and day and night confocal characteristics to achieve clear monitoring over a wide area and in all weather conditions.

[0109] For example, in the field of industrial inspection, this vision system can be applied to industrial cameras and machine vision inspection equipment, utilizing its high pixel resolution and low distortion imaging performance to meet the stringent requirements of precision manufacturing such as dimensional measurement and defect detection.

[0110] By adopting the aforementioned optical lens module, this vision system can achieve multiple performance advantages such as compact structure, ultra-short focal length, large target surface adaptation, low aberration, and day and night confocality without the need for expensive aspherical lenses or special glass materials. It features controllable cost, excellent imaging, and strong environmental adaptability.

[0111] The specific implementation of the optical lens module and vision system in this application can refer to the various embodiments of the above-described industrial lens. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above-described embodiments, and will not be described in detail here.

[0112] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0113] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. An industrial lens, characterized in that, From the object side to the image side along the optical axis, it includes the first lens group, the aperture stop (14), and the second lens group in sequence; The first lens group includes: The first lens (1) has negative optical power; The second lens (2) has negative optical power; The third lens (3) has negative optical power; The fourth lens (4) has positive optical power; The first cemented lens group consists of the fifth lens (5) and the sixth lens (6), wherein the fifth lens (5) has negative optical power and the sixth lens (6) has positive optical power; The second cemented lens group consists of a seventh lens (7) and an eighth lens (8), wherein the seventh lens (7) has positive optical power and the eighth lens (8) has negative optical power; The second lens group includes: The third cemented lens group consists of the ninth lens (9) and the tenth lens (10), wherein the ninth lens (9) has negative optical power and the tenth lens (10) has positive optical power; The eleventh lens (11) has positive optical power; The twelfth lens (12) has positive optical power; Among them, the first lens (1) to the twelfth lens (12) are all spherical glass lenses.

2. The industrial lens according to claim 1, characterized in that, The first lens (1), the second lens (2) and the third lens (3) are all meniscus negative lenses; The fourth lens (4) is a meniscus lens; The fifth lens (5) is a biconcave negative lens, and the sixth lens (6) is a biconvex positive lens; The seventh lens (7) is a biconvex positive lens, and the eighth lens (8) is a biconcave negative lens; The ninth lens (9) is a biconcave negative lens, and the tenth lens (10) is a biconvex positive lens; The eleventh lens (11) is a meniscus lens; The twelfth lens (12) is a biconvex positive lens.

3. The industrial lens according to claim 1, characterized in that, The industrial lens satisfies the following relationship: 0.2≤Fa / Fb≤0.6, where Fa is the combined focal length of the first lens group and Fb is the combined focal length of the second lens group.

4. The industrial lens according to claim 1, characterized in that, The industrial lens satisfies the following relationship: -2.8≤F1 / F≤-1.5; -7.3≤F2 / F≤-4; -5.5≤F3 / F≤-4.6; 3.3≤F4 / F≤5; 2.2≤F11 / F≤2.7; 2≤F12 / F≤2.3; Wherein, F is the effective focal length of the industrial lens, and F1, F2, F3, F4, F11, and F12 are the effective focal lengths of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the eleventh lens (11), and the twelfth lens (12), respectively.

5. The industrial lens according to claim 1 or 4, characterized in that, The industrial lens satisfies the following relationship: -4.8≤F5 / F6≤-3.1; -0.7≤F7 / F8≤-0.4; -0.5≤F9 / F10≤-0.2; Wherein, F5 and F6 are the effective focal lengths of the fifth lens (5) and the sixth lens (6), respectively; F7 and F8 are the effective focal lengths of the seventh lens (7) and the eighth lens (8), respectively; and F9 and F10 are the effective focal lengths of the ninth lens (9) and the tenth lens (10), respectively.

6. The industrial lens according to claim 1, characterized in that, The lenses in the first lens group satisfy the following conditions: The object-side surface curvature radius R1 of the first lens (1) satisfies 26mm < R1 < 34mm, and the image-side surface curvature radius R2 satisfies 9mm < R2 < 15mm; The object-side surface curvature radius R1 of the second lens (2) satisfies 49mm < R1 < 783mm, and the image-side surface curvature radius R2 satisfies 16mm < R2 < 43mm; The object-side surface curvature radius R1 of the third lens (3) satisfies -329mm < R1 < -38mm, and the image-side surface curvature radius R2 satisfies 30mm < R2 < 218mm. The object-side surface curvature radius R1 of the fourth lens (4) satisfies 33mm < R1 < 45mm, and the image-side surface curvature radius R2 satisfies -128mm < R2 < 1969mm.

7. The industrial lens according to claim 6, characterized in that, The object-side surface curvature radius R1 of the fifth lens (5) satisfies -37mm < R1 < -24mm, and the image-side surface curvature radius R2 satisfies 22mm < R2 < 27mm. The object-side surface curvature radius R1 of the sixth lens (6) satisfies 22mm < R1 < 27mm, and the image-side surface curvature radius R2 satisfies -26mm < R2 < -23mm. The object-side surface curvature radius R1 of the seventh lens (7) satisfies 11mm < R1 < 13mm, and the image-side surface curvature radius R2 satisfies -69mm < R2 < -29mm. The object-side surface curvature radius R1 of the eighth lens (8) satisfies -69mm < R1 < -29mm, and the image-side surface curvature radius R2 satisfies 55mm < R2 < 67mm.

8. The industrial lens according to claim 1, characterized in that, The lenses in the second lens group satisfy the following conditions: The object-side surface curvature radius R1 of the ninth lens (9) satisfies -8mm < R1 < -6mm, and the image-side surface curvature radius R2 satisfies 15mm < R2 < 18mm. The object-side surface curvature radius R1 of the tenth lens (10) satisfies 15mm < R1 < 18mm, and the image-side surface curvature radius R2 satisfies -12mm < R2 < -8mm. The object-side surface curvature radius R1 of the eleventh lens (11) satisfies -622mm < R1 < -46mm, and the image-side surface curvature radius R2 satisfies -26mm < R2 < -20mm. The object-side surface curvature radius R1 of the twelfth lens (12) satisfies 27mm < R1 < 29mm, and the image-side surface curvature radius R2 satisfies -61mm < R2 < -53mm.

9. The industrial lens according to claim 1, characterized in that, The total optical length (TTL) of the industrial lens must satisfy: TTL≤70mm; The effective focal length F of the industrial lens satisfies: F≤16mm.

10. The industrial lens according to claim 1, characterized in that, The working distance WD of the industrial lens is WD≥1000mm, and the working distance WD is the axial distance from the object-side surface of the first lens (1) of the industrial lens to the object plane where the observed object is located. The industrial lens can achieve day and night confocal imaging in the visible light and near-infrared bands.

11. An optical lens module, characterized in that, include: The industrial lens according to any one of claims 1-10; A photosensitive chip (15) disposed on the image side of the industrial lens; and, A glass plate (13) is disposed between the industrial lens and the photosensitive chip (15).

12. A vision system, characterized in that, include: The optical lens module as described in claim 11.

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