Industrial lens

Abstract

The industrial lens comprises a first lens group and a second lens group which are coaxially arranged in sequence from an object space to an image space, and a diaphragm is arranged between the first lens group and the second lens group; the first lens group comprises a preorder lens group, the preorder lens group comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from the object space to the image space, the first lens group further comprises a fifth lens, and the fifth lens is located at the image space of the fourth lens; the second lens group comprises a sixth lens, a seventh lens, an eighth lens and a ninth lens; the industrial lens satisfies the following relational expressions: fu1 / f is less than or equal to 5.8; fu2 / f is greater than or equal to 1.8; sDmax / TTL < = 0.36; wherein fu1 is the effective focal length of the first lens group in the industrial lens, fu2 is the effective focal length of the second lens group in the industrial lens, f is the effective focal length of the industrial lens, SDmax is the clear aperture of the maximum lens in the industrial lens, and TTL is the total optical length of the industrial lens. The imaging quality can be improved, and the industrial requirement for miniaturization can be met at the same time.

Description

Technical Field

[0001] The present application relates to the field of optical lenses, and in particular to an industrial lens. Background Art

[0002] In industrial automation systems, industrial lenses play a vital role as key components for capturing real-time data on production sites. Their performance directly determines the accuracy and reliability of information obtained by the system. Given the particularity of the industrial environment, industrial lenses often need to perform far better than ordinary lenses, including but not limited to: ensuring high definition and imaging quality of captured images, and designing a more compact size to adapt to complex and changing industrial environments.

[0003] On the one hand, ensuring that the high resolution of industrial lenses can capture tiny and critical production details is the key to ensuring clear image details and complete information, which requires industrial lenses to have excellent optical performance. On the other hand, high relative illumination lenses can maintain image consistency and readability in complex lighting environments, which also affects image clarity and is also crucial to ensuring the accuracy and stability of production monitoring. In addition, as industrial automation equipment develops towards a more compact and efficient direction, miniaturization has become an important trend in industrial lens design, which requires lenses to be as small as possible while maintaining high performance to adapt to increasingly compact equipment layouts.

[0004] However, although there are many industrial lens products on the market, they still have obvious shortcomings in meeting the above-mentioned specific high-performance requirements at the same time. Therefore, developing an industrial lens that can overcome the defects of existing technologies and has the characteristics of high resolution, high relative illumination and miniaturization has become an urgent need to promote the advancement of industrial automation technology and industrial upgrading. Summary of the invention

[0005] In order to promote the overall improvement of production efficiency and product quality in the industrial production process, the present application provides an industrial lens that can ensure high-definition images, improve imaging quality, and meet the industrial needs of miniaturization.

[0006] The industrial lens provided in this application adopts the following technical solution: An industrial lens comprises a first lens group and a second lens group coaxially arranged in sequence from an object side to an image side, wherein an aperture is arranged between the first lens group and the second lens group; The first lens group includes a preceding lens group, the preceding lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the object side to the image side, the first lens group also includes a fifth lens, the fifth lens is located on the image side of the fourth lens; The second lens group includes a sixth lens, a seventh lens, an eighth lens and a ninth lens; The industrial lens satisfies the following relationship: |f u1 / f|≤5.8; |f u2 / f|≥1.8; SD max / TTL≤0.36; Among them, f u1 is the effective focal length of the first lens group in the industrial lens, f u2 is the effective focal length of the second lens group in the industrial lens, f is the effective focal length of the industrial lens, SD max is the clear aperture of the largest lens in the industrial lens, and TTL is the total optical length of the industrial lens.

[0007] By adopting the above technical solution, the industrial lens is divided into two lens groups, and the effective focal lengths of the two lens groups are reasonably allocated to the proportion of the effective focal length of the entire lens, so as to achieve high relative illumination and high resolution of the optical system. The incident light is controlled by the clear aperture to further achieve high relative illumination. At the same time, the ratio of the clear aperture of the largest lens in the industrial lens to the total optical length is controlled to achieve miniaturization of the entire lens.

[0008] Preferably, the industrial lens also satisfies the following relationship: 3.3≤FOV / CRA≤3.6; Among them, FOV is the maximum field of view angle of the industrial lens, and CRA is the chief ray angle of the optical system formed by the industrial lens.

[0009] By adopting the above technical solution, the position of each lens in the optical system is reasonably allocated, so as to control the ratio between the maximum field of view angle and the main light angle, meet the requirements of low distortion of imaging, and further improve the quality of imaging.

[0010] Preferably, the sixth lens is a biconvex positive lens, the seventh lens is a biconcave negative lens, and the sixth lens and the seventh lens are a cemented lens.

[0011] By adopting the above technical solution, the sixth lens and the seventh lens are bonded together to eliminate or balance the chromatic aberration and distortion produced by the lenses, reduce tolerance sensitivity, and improve imaging quality.

[0012] Preferably, the industrial lens satisfies the following relationship: 32.8≤|VD6-VD7|; Wherein, VD6 is the Abbe number of the sixth lens, and VD7 is the Abbe number of the seventh lens.

[0013] By adopting the above technical solution and rationally selecting the Abbe numbers of the sixth lens and the seventh lens constituting the cemented lens, the chromatic aberration of the optical system can be effectively reduced and the imaging quality can be improved.

[0014] Preferably, the industrial lens satisfies the following relationship: Nd5≥1.8; Wherein, Nd5 is the refractive index of the fifth lens.

[0015] By adopting the above technical solution, using a high refractive index material for the fifth lens and controlling the optical focal length of the fifth lens, the miniaturization of the optical lens can be further achieved.

[0016] Preferably, the industrial lens satisfies the following relationship: Nd9≤1.8; VD9≥47.9; Wherein, Nd9 is the refractive index of the ninth lens, and VD9 is the Abbe number of the ninth lens.

[0017] By adopting the above technical solution, controlling the Abbe number and refractive index of the ninth lens, and selecting a suitable combination of Abbe number and refractive index, it is helpful to reduce the aberration and distortion of the lens, and ensure that the lens can provide clear and accurate imaging effects under various lighting conditions.

[0018] Preferably, the first lens of the preceding lens group is a biconvex positive lens, the second lens is a meniscus positive lens convex toward the object side, the third lens is a biconcave negative lens, and the fourth lens is a meniscus positive lens convex toward the image side.

[0019] Preferably, the fifth lens is a meniscus positive lens convex toward the object side, the eighth lens is a plano-convex positive lens convex toward the image side, and the ninth lens is a biconvex positive lens.

[0020] Preferably, the fifth lens is a biconvex positive lens, the eighth lens is a plano-convex positive lens convex toward the image side, and the ninth lens is a plano-convex positive lens convex toward the object side.

[0021] Preferably, the fifth lens is a biconvex positive lens, the eighth lens is a plano-convex positive lens convex toward the image side, and the ninth lens is a meniscus positive lens convex toward the object side.

[0022] By adopting the above technical solution and adjusting the lens shapes of the fifth lens and the ninth lens, three different feasible lens shape combinations in industrial lenses are given, which provides a basis for the specific implementation of this solution.

[0023] In summary, this application has at least the following beneficial effects: 1. This application divides the industrial lens into two lens groups, and reasonably allocates the effective focal lengths of the two lens groups to the proportion of the effective focal length of the entire lens, so as to achieve high relative illumination and high resolution of the optical system, and improve imaging clarity and quality; at the same time, the ratio of the clear aperture of the largest lens in the industrial lens to the total optical length is controlled to achieve miniaturization of the entire lens.

[0024] 2. This application reasonably allocates the positions of each lens in the optical system to control the ratio between the maximum field of view angle and the main ray angle, while achieving the requirement of low distortion, maintaining the optical performance of the lens and further improving the quality of imaging.

[0025] 3. The present invention reduces the chromatic aberration of imaging and further realizes the miniaturization of the lens by introducing a cemented lens into the imaging system and controlling the Abbe number of the cemented lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a lens layout diagram of an industrial lens of the present application; Figure 2 is the optical path diagram of Example 1 of the present application; Figure 3 This is the MTF curve of Example 1 of the present application under visible light 450nm-656nm; Figure 4 This is a field curvature / distortion diagram of Example 1 of the present application under visible light 450nm-656nm; Figure 5 is a longitudinal aberration diagram of Example 1 of the present application under visible light 450nm-656nm; Figure 6 is a lateral chromatic aberration diagram of Example 1 of the present application under visible light 656nm; Figure 7 is a relative illumination diagram of Example 1 of the present application under visible light 656nm; Figure 8 is a light path diagram of Example 2 of the present application; Fig. 9 This is the MTF curve of Example 2 of the present application under visible light 450nm-656nm; Fig.10 This is a field curvature / distortion diagram of Example 2 of the present application under visible light 450nm-656nm; Fig.11 is a longitudinal aberration diagram of Example 2 of the present application under visible light 450nm-656nm; Fig.12 is a lateral chromatic aberration diagram of Example 2 of the present application under visible light 656nm; Fig.13is a relative illumination diagram of Example 2 of the present application under visible light 656nm; Fig.14 is a light path diagram of Example 3 of the present application; Fig.15 This is the MTF curve diagram of Example 3 of the present application under visible light 450nm-656nm; Fig.16 is a field curvature / distortion diagram of Example 3 of the present application under visible light 450nm-656nm; Fig.17 is a longitudinal aberration diagram of Example 3 of the present application under visible light 450nm-656nm; Fig.18 is a lateral chromatic aberration diagram of Example 3 of the present application under visible light 656nm; Fig.19 This is a relative illumination diagram of Example 3 of the present application under visible light of 656 nm.

[0027] Description of reference numerals: 1. First lens group; 2. Second lens group; 3. Aperture; 4. First lens; 5. Second lens; 6. Third lens; 7. Fourth lens; 8. Fifth lens; 9. Sixth lens; 10. Seventh lens; 11. Eighth lens; 12. Ninth lens; 13. Protective glass; 14. Imaging surface. DETAILED DESCRIPTION

[0028] The present application provides an industrial lens. To make the purpose, technical solution and advantages of the present application clearer, the implementation method of the present application will be further described in detail below.

[0029] The technical solutions in some embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the specification. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0030] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0031] like Figure 1 As shown, the present application proposes an industrial lens, comprising a first lens group 1 and a second lens group 2 coaxially arranged in sequence from the object side to the image side, and an aperture 3 is arranged between the first lens group 1 and the second lens group 2; Dividing the industrial lens into two lens groups, namely the first lens group 1 and the second lens group 2, makes it easier to control the optical focal length separately, thereby allocating the position or parameters of each lens to improve the optical performance.

[0032] The first lens group 1 includes a preceding lens group, which includes a first lens 4, a second lens 5, a third lens 6 and a fourth lens 7 arranged in sequence from the object side to the image side.

[0033] In the embodiment of the present application, the first lens 4 of the preceding lens group is a double convex positive lens, the second lens 5 is a meniscus positive lens convex to the object side, the third lens 6 is a double concave negative lens, and the fourth lens 7 is a meniscus positive lens convex to the image side.

[0034] The first lens group 1 further includes a fifth lens 8, which is located on the image side of the fourth lens 7; The second lens group 2 includes a sixth lens 9 , a seventh lens 10 , an eighth lens 11 and a ninth lens 12 .

[0035] In order to improve the imaging clarity and realize the miniaturization of industrial lenses, the industrial lenses satisfy the following relationship: |f u1 / f|≤5.8; |f u2 / f|≥1.8; SD max / TTL≤0.36; Among them, f u1 is the effective focal length of the first lens group 1 in the industrial lens; f u2 is the effective focal length of the second lens group 2 in the industrial lens; f is the effective focal length of the industrial lens; SD max It is the clear aperture of the largest lens in industrial lenses; TTL is the total optical length of the industrial lens.

[0036] Reasonably distribute the effective focal length f of the two lens groups u1 、f u2 The proportion of the effective focal length f of the entire lens can achieve high relative illumination and high resolution of the optical system, further improving image clarity and quality.

[0037] Control the maximum clear aperture SD of the lens in the industrial lens max The ratio of the total optical length TTL enables the miniaturization of the entire lens.

[0038] In order to further improve the imaging quality, the maximum field of view FOV of the industrial lens and the chief ray angle CRA of the optical system formed by the industrial lens also satisfy the following relationship: 3.3≤FOV / CRA≤3.6.

[0039] By using the above relationship, the positions of the lenses in the optical system are reasonably allocated, thereby controlling the ratio between the maximum field of view angle and the main ray angle, which can meet the requirements of low imaging distortion and further improve the imaging quality and clarity.

[0040] In the embodiment of the present application, the sixth lens 9 is a biconvex positive lens, the seventh lens 10 is a biconcave negative lens, and the sixth lens 9 and the seventh lens 10 are cemented lenses.

[0041] The sixth lens 9 and the seventh lens 10 are bonded together to eliminate or balance the chromatic aberration and distortion produced by the lenses, reduce the tolerance sensitivity, improve the imaging quality, and further enhance the imaging clarity.

[0042] Further, the Abbe number VD6 of the sixth lens element 9 and the Abbe number VD7 of the seventh lens element 10 satisfy the following relationship: 32.8≤|VD6-VD7|; By controlling the Abbe numbers of the sixth lens 9 and the seventh lens 10 constituting the cemented lens, the chromatic aberration of the optical system can be effectively reduced, the imaging quality can be improved, and the imaging clarity can be further enhanced.

[0043] Furthermore, the refractive index Nd5 of the fifth lens 8 satisfies the following relationship: Nd5≥1.8.

[0044] By controlling the optical power of the fifth lens 8 , specifically, by using a material with a high refractive index for the fifth lens 8 , the optical lens can be further miniaturized.

[0045] Further, the refractive index Nd9 of the ninth lens 12 satisfies the following relationship: Nd9≤1.8; At the same time, the Abbe number VD9 of the ninth lens 12 satisfies the following relationship: VD9≥47.9.

[0046] By controlling the Abbe number and the refractive index of the ninth lens 12 and selecting a suitable combination of the Abbe number and the refractive index, it is helpful to reduce the aberration and distortion of the lens, and ensure that the lens can provide clear and accurate imaging effects under various lighting conditions, thereby improving the imaging clarity.

[0047] In summary, in the embodiments of the present application, the industrial lens is provided with a first lens 4, a second lens 5, a third lens 6, a fourth lens 7, a fifth lens 8, a sixth lens 9, a seventh lens 10, an eighth lens 11 and a ninth lens 12 in sequence along the optical axis from the object side to the image side.

[0048] Among them, the first lens 4 is a double convex positive lens with positive optical power, a large aperture and a large radius of curvature, which is conducive to the industrial lens to obtain light at a large angle and make it stably incident on the rear optical system.

[0049] The second lens 5 is a positive meniscus lens convex toward the object side and has positive focal power. It can compress the light collected by the first lens 4 and reduce the diameter of the incident light, which is beneficial to control the volume of the lens and achieve miniaturization.

[0050] The third lens 6 is a double concave negative lens with negative optical power, which can diverge the light collected by the second lens 5 to achieve correction of light of different wavelengths, which is beneficial to improving imaging quality.

[0051] The fourth lens 7 is a positive meniscus lens convex toward the image side and has positive focal power. It can focus the light collected by the third lens 6, which is beneficial to control the volume of the lens and achieve miniaturization.

[0052] The fifth lens 8 has positive refractive power and can focus the light collected by the fourth lens 7 so that the light is more evenly irradiated to the target area; At the same time, in a specific implementable manner, the optical power of the fifth lens 8 is reasonably controlled to make TTL ≤ 72.9202 mm to meet the demand for miniaturization.

[0053] The sixth lens 9 is a biconvex positive lens with positive power, the seventh lens 10 is a biconcave negative lens with negative power, and the sixth lens 9 and the seventh lens 10 are cemented lenses, which can eliminate or balance the chromatic aberration and distortion produced by the lens and reduce the tolerance sensitivity; Meanwhile, the sixth lens 9 and the seventh lens 10 are both glass lenses, which can effectively improve the stability and durability of the lenses.

[0054] The eighth lens 11 is a plano-convex positive lens convex toward the image side, has positive focal power, and can focus the light collected by the cemented lens so that the light is incident on the ninth lens 12 stably.

[0055] The ninth lens 12 has positive refractive power, and can focus the light collected by the eighth lens 11 and correct the aberration to optimize the imaging performance of the lens group; At the same time, the ninth lens 12 of this embodiment uses glass that is friendly to thermal drift, which can effectively improve the stability of the lens.

[0056] All lenses of the present application are made of glass material with a conventional refractive index, which effectively reduces the manufacturing cost.

[0057] In order to explain the above scheme more clearly, three different embodiments that conform to the above scheme are given below as specific implementation methods of the present application.

[0058] Embodiment 1: like Figure 2 As shown, in Embodiment 1, the fifth lens element 8 is a positive meniscus lens convex toward the object, and the ninth lens element 12 is a double convex positive lens.

[0059] Based on the structure of the industrial lens provided above, in this embodiment, the industrial lens includes a biconvex positive lens, a meniscus positive lens convex toward the object side, a biconcave negative lens, a meniscus positive lens convex toward the image side, a meniscus positive lens convex toward the object side, an aperture 3, a biconvex positive lens, a biconcave negative lens, a plano-convex positive lens convex toward the image side, a biconvex positive lens, a protective glass 13 and an imaging surface 14 arranged coaxially in sequence.

[0060] Table 1 shows various parameters of multiple lenses of the industrial lens in this embodiment 1.

[0061] Table 1: Combination Figure 1 He Ru Figure 2 As shown, the object side surface S1 and the image side surface S2 of the first lens 4, i.e., the biconvex positive lens, are both convex surfaces; The second lens 5, i.e., a positive meniscus lens convex toward the object, has a convex object side surface S3 and a concave image side surface S4; The object side surface S5 and the image side surface S6 of the third lens element 6, i.e., the double concave negative lens, are both concave surfaces; The fourth lens element 7, i.e., a positive meniscus lens convex toward the image side, has a concave object side surface S7 and a convex image side surface S8; The fifth lens 8, i.e., a positive meniscus lens convex toward the object, has an object-side surface S9 that is convex, and an image-side surface S10 that is concave; The object side surface S12 and the image side surface S13 of the sixth lens element 9, i.e., the biconvex positive lens, are both convex surfaces; The object side surface S13 and the image side surface S14 of the seventh lens element 10, i.e., the double concave negative lens, are both concave surfaces; Since the sixth lens 9 and the seventh lens 10 are a cemented lens, they share S13, which is convex relative to the sixth lens 9 and concave relative to the seventh lens 10; The object side surface S15 of the eighth lens element 11, i.e., a plano-convex positive lens convex toward the image side, is a flat surface, and the image side surface S16 is a convex surface; The object side surface S17 and the image side surface S18 of the ninth lens 12, i.e., the biconvex positive lens, are both convex surfaces; S18 and S19 are two sides of the protective glass 13 .

[0062] IMA is the imaging surface 14 .

[0063] In this embodiment 1, the parameters of the industrial lens are shown in Table 2.

[0064] Table 2: FOV 48.0000 <![CDATA[f u1 ]]> 41.2930 <![CDATA[f u2 ]]> 23.6917 <![CDATA[VD6]]> 60.37 <![CDATA[VD7]]> 27.55 <![CDATA[VD9]]> 47.92 f 12.2838 TTL 63.2593 CRA 14.1250 <![CDATA[SD max ]]> 22.5723 <![CDATA[Nd5]]> 1.81 <![CDATA[Nd9]]> 1.72 As can be seen from Table 2 above, in this embodiment 1, the effective focal length f of the first lens group 1 in the industrial lens is u1 The relationship between the effective focal length f of the entire lens is: |f u1 / f|=3.3616, satisfying |f u1 / f|≤5.8.

[0065] is the effective focal length f of the second lens group 2 in the industrial lens u2 The relationship between the effective focal length f of the entire lens is: |f u2 / f|=1.9287, satisfying |f u2 / f|≥1.8.

[0066] The maximum lens aperture SD max Relationship between SD and total optical length TTL: max / TTL=0.3568, meets SD max / TTL≤0.36.

[0067] The relationship between the maximum field of view FOV of an industrial lens and the chief ray angle CRA of the optical system formed by the industrial lens is: FOV / CRA=3.3982, satisfying 3.3≤FOV / CRA≤3.6.

[0068] The relationship between the Abbe number VD6 of the sixth lens 9 and the Abbe number VD7 of the seventh lens 10 is: |VD6-VD7|=32.8208, satisfying 32.8≤|VD6-VD7|.

[0069] The refractive index of the fifth lens 8 is Nd5=1.8052, satisfying Nd5≥1.8.

[0070] The refractive index of the ninth lens 12 is Nd9=1.72, satisfying Nd9≤1.8.

[0071] The Abbe number VD9 of the ninth lens 12 is 47.92, satisfying VD9≥47.9.

[0072] like Figure 3 The figure shows the MTF diagram of Example 1 under visible light of 450nm-656nm. The distance from the center of the image field to the edge of the image field is used as the horizontal coordinate. Curves of different colors represent different fields of view. It can be seen that the MTF values ​​of each field of view are relatively concentrated, and the image quality is uniform. At 60lp / mm, the optical transfer function is greater than 0.7, and the clarity of the image is guaranteed, reflecting that the industrial lens has a high resolution.

[0073] Figure 4This is the field curvature / distortion diagram of this embodiment 1. The left part represents the field curvature. It can be seen from the figure that the field curvature values ​​in the figure are all controlled within ±0.07mm, indicating that the field curvature of the industrial lens is well corrected; the right part represents the distortion, wherein the horizontal axis represents the distortion size. It can be seen from the figure that the distortion value is controlled within -1%, indicating that the distortion of the industrial lens is well corrected and the distortion of the imaging picture is well controlled.

[0074] Figure 5 This is the longitudinal aberration diagram of Example 1. It can be seen from the figure that the aberration values ​​from the shortest wavelength to the longest wavelength in the figure are all controlled within ±0.07mm, indicating that the longitudinal aberration of the industrial lens is well corrected.

[0075] Figure 6 This is a lateral chromatic aberration diagram of the present embodiment 1. It can be seen from the diagram that the lateral chromatic aberration is small and has a high image color reproduction within the diffraction range.

[0076] Figure 7 This is a relative illumination diagram of the present embodiment 1. It can be seen from the diagram that the brightness changes from the center to the edge are relatively uniform, so the imaging effect is good.

[0077] Depend on Figure 3-Figure 7 It can be seen that this industrial lens has the effects of high resolution, high relative illumination, low distortion, low chromatic aberration, high imaging quality and good optical performance.

[0078] Embodiment 2: like Figure 8 As shown, in Example 2, the fifth lens 8 is a biconvex positive lens, and the ninth lens 12 is a plano-convex positive lens convex toward the object side.

[0079] Based on the structure of the industrial lens provided above, in this embodiment, the industrial lens includes a biconvex positive lens, a meniscus positive lens convex toward the object side, a biconcave negative lens, a meniscus positive lens convex toward the image side, a biconvex positive lens, an aperture 3, a biconvex positive lens, a biconcave negative lens, a plano-convex positive lens convex toward the image side, a plano-convex positive lens convex toward the object side, a protective glass 13, and an imaging surface 14, which are arranged coaxially in sequence.

[0080] Table 3 shows various parameters of multiple lenses of the industrial lens in this embodiment 2.

[0081] Table 3: Combination Figure 1 He Ru Figure 8As shown, the object side surface S1 and the image side surface S2 of the first lens 4, i.e., the biconvex positive lens, are both convex surfaces; the object side surface S3 of the second lens 5, i.e., the meniscus positive lens convex toward the object side, is convex, and the image side surface S4 is concave; The object side surface S5 and the image side surface S6 of the third lens element 6, i.e., the double concave negative lens, are both concave surfaces; The fourth lens element 7, i.e., a positive meniscus lens convex toward the image side, has a concave object side surface S7 and a convex image side surface S8; The object side surface S9 and the image side surface S10 of the fifth lens element 8, i.e., the biconvex positive lens, are both convex surfaces; The object side surface S12 and the image side surface S13 of the sixth lens element 9, i.e., the biconvex positive lens, are both convex surfaces; The object side surface S13 and the image side surface S14 of the seventh lens element 10, i.e., the double concave negative lens, are both concave surfaces; Since the sixth lens 9 and the seventh lens 10 are a cemented lens, they share S13, which is convex relative to the sixth lens 9 and concave relative to the seventh lens 10; The object side surface S15 of the eighth lens element 11, i.e., a plano-convex positive lens convex toward the image side, is a flat surface, and the image side surface S16 is a convex surface; The ninth lens 12, i.e., a plano-convex positive lens convex toward the object, has an object-side surface S17 that is a convex surface and an image-side surface S18 that is a flat surface; S18 and S19 are two sides of the protective glass 13; IMA is the imaging surface 14 .

[0082] In this embodiment 2, the parameters of the industrial lens are shown in Table 4.

[0083] Table 4: FOV 48.0000 <![CDATA[f u1 ]]> 71.1533 <![CDATA[f u2 ]]> 22.4856 <![CDATA[VD6]]> 60.37 <![CDATA[VD7]]> 27.55 <![CDATA[VD9]]> 47.92 f 12.4055 TTL 72.9202 CRA 14.1341 <![CDATA[SD max ]]> 22.0214 <![CDATA[Nd5]]> 1.81 <![CDATA[Nd9]]> 1.72 As can be seen from Table 4 above, in this embodiment 2, the effective focal length f of the first lens group 1 in the industrial lens is u1 The relationship between the effective focal length f of the entire lens is: |f u1 / f|=5.7356, satisfying |f u1 / f|≤5.8.

[0084] is the effective focal length f of the second lens group 2 in the industrial lens u2 The relationship between the effective focal length f of the entire lens is: |f u2 / f|=1.8125, satisfying |f u2 / f|≥1.8.

[0085] The maximum lens aperture SD max Relationship between SD and total optical length TTL: max / TTL=0.3020, meets SD max / TTL≤0.36.

[0086] The relationship between the maximum field of view FOV of an industrial lens and the chief ray angle CRA of the optical system formed by the industrial lens is: FOV / CRA=3.3960, satisfying 3.3≤FOV / CRA≤3.6.

[0087] The relationship between the Abbe number VD6 of the sixth lens 9 and the Abbe number VD7 of the seventh lens 10 is: |VD6-VD7|=32.8208, satisfying 32.8≤|VD6-VD7|.

[0088] The refractive index of the fifth lens 8 is Nd5=1.8052, satisfying Nd5≥1.8.

[0089] The refractive index of the ninth lens 12 is Nd9=1.72, satisfying Nd9≤1.8.

[0090] The Abbe number VD9 of the ninth lens 12 is 47.92, satisfying VD9≥47.9.

[0091] like Fig. 9 The figure shows the MTF diagram of this embodiment under visible light 450nm-656nm, with the distance from the center of the image field to the edge of the image field as the horizontal axis. Curves of different colors represent different fields of view. It can be seen that the MTF values ​​of each field of view are relatively concentrated, and the image quality is uniform. At 60lp / mm, the optical transfer function is greater than 0.7, and the clarity of the image is guaranteed, reflecting that this industrial lens has a high resolution.

[0092] Fig.10 This is a field curvature / distortion diagram of the present embodiment. The left part represents the field curvature. It can be seen from the figure that the field curvature values ​​in the figure are all controlled within ±0.05mm, indicating that the field curvature of the industrial lens is well corrected; the right part represents the distortion, wherein the horizontal axis represents the distortion size. It can be seen from the figure that the distortion value is controlled within -3%, indicating that the distortion of the industrial lens is well corrected and the distortion of the imaging picture is well controlled.

[0093] Fig.11 This is a longitudinal aberration diagram of the present embodiment. It can be seen from the figure that the aberration values ​​from the shortest wavelength to the longest wavelength in the figure are all controlled within ±0.05mm, indicating that the longitudinal aberration of the industrial lens is well corrected.

[0094] Fig.12 This is a lateral chromatic aberration diagram of this embodiment. It can be seen from the diagram that the lateral chromatic aberration is small and has a high image color reproduction within the diffraction range.

[0095] Fig.13 This is a relative illumination diagram of this embodiment. It can be seen from the diagram that when the field angle in the Y direction is within 16.9, the relative illumination is greater than 90%, so the imaging effect is good.

[0096] Depend on Figure 9-13 It can be seen that this industrial lens has the effects of high resolution, high relative illumination, low distortion, low chromatic aberration, high imaging quality and good optical performance.

[0097] Embodiment 3: like Fig.14 As shown, in Example 3, the fifth lens 8 is a biconvex positive lens, the eighth lens 11 is a plano-convex positive lens convex toward the image side, and the ninth lens 12 is a meniscus positive lens convex toward the object side.

[0098] Based on the structure of the industrial lens provided above, in this embodiment, the industrial lens includes a biconvex positive lens, a meniscus positive lens convex toward the object side, a biconcave negative lens, a meniscus positive lens convex toward the image side, a biconvex positive lens, an aperture 3, a biconvex positive lens, a biconcave negative lens, a plano-convex positive lens convex toward the image side, a meniscus positive lens convex toward the object side, a protective glass 13, and an imaging surface 14, which are arranged coaxially in sequence.

[0099] Table 5 shows various parameters of multiple lenses of the industrial lens in this embodiment 3.

[0100] Table 5: Combination Figure 1 He Ru Fig.14 As shown, the object side surface S1 and the image side surface S2 of the first lens 4, i.e., the biconvex positive lens, are both convex surfaces; The second lens 5, i.e., a positive meniscus lens convex toward the object, has a convex object side surface S3 and a concave image side surface S4; The object side surface S5 and the image side surface S6 of the third lens element 6, i.e., the double concave negative lens, are both concave surfaces; The fourth lens element 7, i.e., a positive meniscus lens convex toward the image side, has a concave object side surface S7 and a convex image side surface S8; The object side surface S9 and the image side surface S10 of the fifth lens element 8, i.e., the biconvex positive lens, are both convex surfaces; The object side surface S12 and the image side surface S13 of the sixth lens element 9, i.e., the biconvex positive lens, are both convex surfaces; The object side surface S13 and the image side surface S14 of the seventh lens element 10, i.e., the double concave negative lens, are both concave surfaces; Since the sixth lens 9 and the seventh lens 10 are a cemented lens, they share S13, which is convex relative to the sixth lens 9 and concave relative to the seventh lens 10; The object side surface S15 of the eighth lens element 11, i.e., a plano-convex positive lens convex toward the image side, is a flat surface, and the image side surface S16 is a convex surface; The ninth lens 12, i.e., a positive meniscus lens convex toward the object, has an object-side surface S17 that is convex, and an image-side surface S18 that is concave; S18 and S19 are two sides of the protective glass 13; IMA is the imaging surface 14 .

[0101] In this embodiment 3, the parameters of the industrial lens are shown in Table 6.

[0102] Table 6: As can be seen from Table 6 above, in this embodiment 3, the effective focal length f of the first lens group 1 in the industrial lens is u1 The relationship between the effective focal length f of the entire lens is: |f u1 / f|=5.2198, satisfying |f u1 / f|≤5.8.

[0103] is the effective focal length f of the second lens group 2 in the industrial lens u2 The relationship between the effective focal length f of the entire lens is: |f u2 / f|=1.8524, satisfying |f u2 / f|≥1.8.

[0104] The maximum lens aperture SD max Relationship between SD and total optical length TTL: max / TTL=0.3262, meets SD max / TTL≤0.36.

[0105] The relationship between the maximum field of view FOV of an industrial lens and the chief ray angle CRA of the optical system formed by the industrial lens is: FOV / CRA=3.5935, satisfying 3.3≤FOV / CRA≤3.6.

[0106] The relationship between the Abbe number VD6 of the sixth lens 9 and the Abbe number VD7 of the seventh lens 10 is: |VD6-VD7|=32.8208, satisfying 32.8≤|VD6-VD7|.

[0107] The refractive index of the fifth lens 8 is Nd5=1.8052, satisfying Nd5≥1.8.

[0108] The refractive index of the ninth lens 12 is Nd9=1.72, satisfying Nd9≤1.8.

[0109] The Abbe number VD9 of the ninth lens 12 is 47.92, satisfying VD9≥47.9.

[0110] like Fig.15The figure shows the MTF diagram of this embodiment under visible light 450nm-656nm, with the distance from the center of the image field to the edge of the image field as the horizontal axis. Curves of different colors represent different fields of view. It can be seen that the MTF values ​​of each field of view are relatively concentrated, and the image quality is uniform. At 60lp / mm, the optical transfer function is greater than 0.7, and the clarity of the image is guaranteed, reflecting that this industrial lens has a high resolution.

[0111] Fig.16 This is a field curvature / distortion diagram of the present embodiment. The left part represents the field curvature. It can be seen from the figure that the field curvature values ​​in the figure are all controlled within ±0.07mm, indicating that the field curvature of the industrial lens is well corrected; the right part represents the distortion, wherein the horizontal axis represents the distortion size. It can be seen from the figure that the distortion value is controlled within -2%, indicating that the distortion of the industrial lens is well corrected and the distortion of the imaging picture is well controlled.

[0112] Fig.17 This is a longitudinal aberration diagram of the present embodiment. It can be seen from the figure that the aberration values ​​from the shortest wavelength to the longest wavelength in the figure are all controlled within ±0.07mm, indicating that the longitudinal aberration of the industrial lens is well corrected.

[0113] Fig.18 This is a lateral chromatic aberration diagram of this embodiment. It can be seen from the diagram that the lateral chromatic aberration is small and has a high image color reproduction within the diffraction range.

[0114] Fig.19 This is a relative illumination diagram of this embodiment. It can be seen from the diagram that the brightness changes from the center to the edge is relatively uniform, so the imaging effect is good.

[0115] Depend on Figure 15-19 It can be seen that this industrial lens has the effects of high resolution, high relative illumination, low distortion, low chromatic aberration, high imaging quality and good optical performance.

[0116] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An industrial lens, characterized in that: It comprises a first lens group (1) and a second lens group (2) which are coaxially arranged in sequence from the object side to the image side, and a stop (3) is arranged between the first lens group (1) and the second lens group (2); The first lens group (1) comprises a preceding lens group, wherein the preceding lens group comprises a first lens (4), a second lens (5), a third lens (6) and a fourth lens (7) arranged in sequence from the object side to the image side, and the first lens group (1) further comprises a fifth lens (8), wherein the fifth lens (8) is located on the image side of the fourth lens (7); The second lens group (2) comprises a sixth lens (9), a seventh lens (10), an eighth lens (11) and a ninth lens (12); The industrial lens satisfies the following relationship: |f u1 / f|≤5.8; |f u2 / f|≥1.8; SD max / TTL≤0.36; Among them, f u1 is the effective focal length of the first lens group (1) in the industrial lens, f u2 is the effective focal length of the second lens group (2) in the industrial lens, f is the effective focal length of the industrial lens, SD max is the clear aperture of the largest lens in the industrial lens, and TTL is the total optical length of the industrial lens.

2. An industrial lens according to claim 1, characterized in that: The industrial lens also satisfies the following relationship: 3≤FOV / CRA≤3.6; Among them, FOV is the maximum field of view angle of the industrial lens, and CRA is the chief ray angle of the optical system formed by the industrial lens.

3. An industrial lens according to claim 1, characterized in that: The sixth lens (9) is a double convex positive lens, the seventh lens (10) is a double concave negative lens, and the sixth lens (9) and the seventh lens (10) are cemented lenses.

4. An industrial lens according to claim 3, characterized in that: The industrial lens satisfies the following relationship: 8≤|VD6-VD7|; Wherein, VD6 is the Abbe number of the sixth lens (9), and VD7 is the Abbe number of the seventh lens (10).

5. The industrial lens according to claim 1, characterized in that: The industrial lens satisfies the following relationship: Nd5≥1.8; Wherein, Nd5 is the refractive index of the fifth lens (8).

6. The industrial lens according to claim 1, characterized in that: The industrial lens satisfies the following relationship: Nd9≤1.8; VD9≥47.9; Wherein, Nd9 is the refractive index of the ninth lens (12), and VD9 is the Abbe number of the ninth lens (12).

7. An industrial lens according to claim 3, characterized in that: The first lens (4) of the preceding lens group is a double convex positive lens, the second lens (5) is a positive meniscus lens convex toward the object side, the third lens (6) is a double concave negative lens, and the fourth lens (7) is a positive meniscus lens convex toward the image side.

8. An industrial lens according to claim 7, characterized in that: The fifth lens (8) is a meniscus positive lens convex toward the object side, the eighth lens (11) is a plano-convex positive lens convex toward the image side, and the ninth lens (12) is a double-convex positive lens.

9. An industrial lens according to claim 7, characterized in that: The fifth lens (8) is a biconvex positive lens, the eighth lens (11) is a plano-convex positive lens convex toward the image side, and the ninth lens (12) is a plano-convex positive lens convex toward the object side.

10. An industrial lens according to claim 7, characterized in that: The fifth lens (8) is a biconvex positive lens, the eighth lens (11) is a plano-convex positive lens convex toward the image side, and the ninth lens (12) is a meniscus positive lens convex toward the object side.

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