High-resolution industrial lens

Abstract

The invention discloses a high-resolution industrial lens, and belongs to the field of optical lenses. A high-resolution industrial lens comprises a plurality of lenses, the plurality of lenses are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are coaxially arranged in sequence from an object side to an image side, and each lens is provided with an object side surface facing the object side and an image side surface facing the image side; a diaphragm is arranged between the third lens and the fourth lens, and the diaphragm and the plurality of lenses are coaxially arranged; the first lens, the second lens, the fifth lens, the sixth lens and the seventh lens have positive focal power, and the third lens, the fourth lens and the eighth lens have negative focal power; the industrial lens satisfies the following relational expressions:-6.69 < = (R51-R52) / R52 < =-4.05; 1.78 < = (TTL / f) < = 1.81; wherein R51 is the curvature radius of the object side surface of the fifth lens, R52 is the curvature radius of the image side surface of the fifth lens, TTL is the total optical length of the industrial lens, and f is the effective focal length of the industrial lens. According to the invention, the imaging definition and the miniaturization of the lens are considered, the urgent demand of the market for the high-performance industrial lens is met, and the further development of the industrial automation technology is promoted.

Description

Technical Field

[0001] The present application relates to the technical field of optical lenses, and in particular to a high-resolution industrial lens. Background Art

[0002] In industrial automation systems, industrial lenses, as core visual components, play a vital role. They are widely used in many fields such as machine vision, quality control and automated manufacturing, and are responsible for accurately capturing image data and providing key visual feedback for the system. The performance of industrial lenses directly determines the efficiency level of the entire visual system, and its importance is self-evident.

[0003] In view of the particularity and high requirements of industrial applications, industrial lenses must meet more stringent standards in design than ordinary lenses. Among them, the most critical is to achieve high definition and more compact size. High definition is the basis for ensuring the complete presentation of image details and accurate transmission of information, and is crucial to improving the recognition accuracy and efficiency of machine vision systems. At the same time, with the development of industrial automation technology, the size of industrial lenses has also been put forward to be more compact to adapt to the increasingly complex and space-limited production environment.

[0004] However, although there are many industrial lenses available on the market, they still have shortcomings in meeting the above high standards. In particular, in the field of industrial lenses that pursue extreme image quality, the market demand is increasing, but existing products are difficult to fully meet this demand. This not only limits the overall performance improvement of industrial automation systems, but also restricts the innovation and development of related industries.

[0005] Therefore, developing an industrial lens that combines high definition with compact size is an urgent problem to be solved in this field. Summary of the invention

[0006] The present application provides a high-resolution industrial lens that takes into account both imaging clarity and lens miniaturization, meets the market's urgent demand for high-performance industrial lenses, and promotes the further development of industrial automation technology.

[0007] The high-resolution industrial lens provided in this application adopts the following technical solution: A high-resolution industrial lens, comprising a plurality of lenses, wherein the plurality of lenses are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens coaxially arranged in sequence from the object side to the image side, and each of the lenses has an object side surface facing the object side and an image side surface facing the image side; An aperture is disposed between the third lens and the fourth lens, and the aperture is coaxially arranged with the plurality of lenses; The first lens, the second lens, the fifth lens, the sixth lens and the seventh lens have positive optical power, and the third lens, the fourth lens and the eighth lens have negative optical power; Industrial lenses satisfy the following relationship: -6.69≤(R 51 -R 52 ) / R 52 ≤-4.05; 1.78≤(TTL / f)≤1.81; Among them, R 51 is the radius of curvature of the object side surface of the fifth lens, R 52 is the curvature radius of the image side surface of the fifth lens, TTL is the total optical length of the industrial lens, and f is the effective focal length of the industrial lens.

[0008] By adopting the above technical solution, the curvature radii of the object side and image side of the fifth lens are reasonably adjusted, and then the shape of the lens is adjusted, so as to achieve the high resolution requirement of the industrial lens and ensure the quality and clarity of the imaging; at the same time, by controlling the relationship between the total optical length and the effective focal length of the industrial lens, the miniaturization of the entire industrial lens is achieved.

[0009] Preferably, the second lens is a biconvex positive lens, the third lens is a biconcave negative lens, and the second lens and the third lens form a first cemented lens group.

[0010] By adopting the above technical solution, the second lens and the third lens are glued together, which can effectively improve the chromatic aberration and distortion of the optical system and reduce the assembly sensitivity of the optical system.

[0011] Preferably, the industrial lens also satisfies the following relationship: -2.7≤(f G1 / f)≤-1.8; Among them, f G1 is the effective focal length of the first cemented lens group.

[0012] By adopting the above technical solution, the optical power of the first cemented lens group is reasonably distributed, low distortion and low chromatic aberration of the industrial lens are achieved, high-quality imaging is guaranteed, and imaging clarity is improved.

[0013] Preferably, the fourth lens is a biconcave negative lens, the fifth lens is a biconvex positive lens, and the fourth lens and the fifth lens form a second cemented lens group.

[0014] By adopting the above technical solution, the fourth lens and the fifth lens are glued together, which can effectively improve the chromatic aberration and distortion of the optical system and reduce the assembly sensitivity of the optical system.

[0015] Preferably, the industrial lens also satisfies the following relationship: -12.2≤(f G2 / f)≤-5.6; Among them, f G2 is the effective focal length of the second cemented lens group.

[0016] By adopting the above technical solution, the optical power of the second cemented lens group is reasonably distributed, low distortion and low chromatic aberration of the industrial lens are achieved, high-quality imaging is guaranteed, and imaging clarity is improved.

[0017] Preferably, the industrial lens also satisfies the following relationship: 1.04≤|f1 / f|≤1.14; 0.75≤|f6 / f|≤0.99; Wherein, f1 is the effective focal length of the first lens, and f6 is the effective focal length of the sixth lens.

[0018] By adopting the above technical solution, the effective focal lengths of the first lens and the sixth lens are reasonably set to account for the proportions of the effective focal length of the industrial lens, thereby further improving the resolution of the industrial lens and the imaging clarity.

[0019] Preferably, the sixth lens is a biconvex positive lens, and the refractive index of the sixth lens is Nd6, satisfying the following relationship: Nd6≥1.74.

[0020] By adopting the above technical solution, the imaging picture is made more uniform, thereby forming a clear image, and at the same time it helps to achieve miniaturization of the lens.

[0021] Preferably, the first lens is a positive meniscus lens convex toward the object, the seventh lens is a positive meniscus lens convex toward the object, and the eighth lens is a double concave negative lens.

[0022] Preferably, the first lens is a biconvex positive lens, the seventh lens is a meniscus positive lens convex toward the object side, and the eighth lens is a biconcave negative lens.

[0023] Preferably, the first lens is a biconvex positive lens, the seventh lens is a biconvex positive lens, and the eighth lens is a biconcave negative lens.

[0024] By adopting the above technical solution, three feasible lens shape combinations of each lens in the industrial lens are given, which provides a basis for the specific implementation of this solution.

[0025] In summary, this application has at least the following beneficial effects: 1. The present application achieves the high-resolution requirement of industrial lenses and ensures the quality and clarity of imaging by reasonably adjusting the curvature radii of the object side and image side of the fifth lens and then adjusting the shape of the lens; at the same time, by controlling the relationship between the total optical length and the effective focal length of the industrial lens, the miniaturization of the entire industrial lens is achieved, so that it can adapt to complex and space-limited production environments, thereby promoting the further development of industrial automation technology.

[0026] 2. This application effectively optimizes the optical performance, significantly reduces the chromatic aberration of the image, and further realizes the miniaturization of the lens by using a cemented lens in the lens design.

[0027] 3. This application reduces the distortion of the lens while maintaining the optical performance by optimizing the shape of the lens.

[0028] 4. This application further improves the resolution of the industrial lens and ensures the quality and clarity of the imaging by reasonably setting the effective focal lengths of the first lens and the sixth lens to a certain proportion of the effective focal length of the industrial lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a lens layout diagram of an embodiment of the present application.

[0030] Figure 2 is the optical path diagram of Example 1 of the present application; Figure 3 is the MFT curve diagram of Example 1 of the present application under visible light 455nm-656nm; Figure 4 is a schematic diagram of field curvature / distortion of Example 1 of the present application; Figure 5 is a vertical axis chromatic aberration diagram of Example 1 of the present application under visible light 549nm; Figure 6 is an axial aberration diagram of Example 1 of the present application under visible light 455nm-656nm; Figure 7 is a light path diagram of Example 2 of the present application; Figure 8 is the MFT curve diagram of Example 2 of the present application under visible light 455nm-656nm; Fig. 9 is a schematic diagram of field curvature / distortion of Example 2 of the present application; Fig.10 is a vertical axis chromatic aberration diagram of Example 2 of the present application under visible light 549nm; Fig.11 is an axial aberration diagram of Example 2 of the present application under visible light 455nm-656nm; Fig.12is a light path diagram of Example 3 of the present application; Fig.13 is the MFT curve diagram of Example 3 of the present application under visible light 455nm-656nm; Fig.14 is a schematic diagram of field curvature / distortion of Example 3 of the present application; Fig.15 This is the vertical axis chromatic aberration diagram of Example 3 of the present application under visible light 549nm; Fig.16 It is an axial aberration diagram of Example 3 of the present application under visible light 455nm-656nm.

[0031] Description of reference numerals: 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. Aperture; 10. Protective glass; 11. Imaging surface. DETAILED DESCRIPTION

[0032] The present application provides a high-resolution 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.

[0033] 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.

[0034] 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.

[0035] The present application provides a high-resolution industrial lens, comprising a plurality of lenses, wherein the plurality of lenses are 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 coaxially arranged in sequence from the object side to the image side, and each lens has an object-side surface facing the object side and an image-side surface facing the image side.

[0036] An aperture 9 (ie, STO) is disposed between the third lens 3 and the fourth lens 4, and the aperture 9 is coaxially arranged with the plurality of lenses.

[0037] Aperture 9 improves the imaging quality and the performance of the optical system by limiting the propagation range and direction of the light beam.

[0038] The first lens 1 , the second lens 2 , the fifth lens 5 , the sixth lens 6 and the seventh lens 7 have positive refractive power, and the third lens 3 , the fourth lens 4 and the eighth lens 8 have negative refractive power.

[0039] Industrial lenses satisfy the following relationship: -6.69≤(R 51 -R 52 / R 52 )≤-4.05; 1.78≤(TTL / f)≤1.81; Among them, R 51 is the radius of curvature of the object side surface of the fifth lens 5; R 52 is the curvature radius of the image-side surface of the fifth lens 5; TTL is the total optical length of the industrial lens; f is the effective focal length of the industrial lens.

[0040] In the embodiments of the present application, the curvature of the fifth lens is controlled, and then the shape of the lens is adjusted, so that the high resolution requirements of the industrial lens can be achieved, the resolving power of the industrial lens can be improved, and it is beneficial to capture more details, making the final image clearer and improving the image quality.

[0041] The effective focal length f1 of the first lens 1 and the effective focal length f6 of the sixth lens 6 are controlled to account for the effective focal length f of the entire industrial lens within the above-specified range. In addition, controlling the relationship between the total optical length and the effective focal length f can also meet the demand for miniaturization of industrial lenses and adapt to complex and space-limited production environments.

[0042] In a specific implementation of the present application, the second lens 2 is a biconvex positive lens, the third lens 3 is a biconcave negative lens, and the second lens 2 and the third lens 3 form a first cemented lens group.

[0043] The fourth lens 4 is a double concave negative lens, the fifth lens 5 is a double convex positive lens, and the fourth lens 4 and the fifth lens 5 form a second cemented lens group.

[0044] When the second lens 2 and the third lens 3 are glued together, and the fourth lens 4 and the fifth lens 5 are glued together, the industrial lens also satisfies the following relationship: -2.7≤(f G1 / f)≤-1.8; -12.2≤(f G2 / f)≤-5.6; Among them, f G1 is the effective focal length of the first cemented lens group; f G2 is the effective focal length of the second cemented lens group.

[0045] In the embodiment of the present application, the second lens 2 and the third lens 3 are glued to each other, and the fourth lens 4 and the fifth lens 5 are glued to each other, and the optical power of the first glued lens group and the second glued lens group is reasonably allocated by the above formula, which can effectively improve the chromatic aberration and distortion of the optical system, reduce the assembly sensitivity of the optical system, and further improve the clarity of the imaging, thereby achieving low distortion and low chromatic aberration of the industrial lens and ensuring high-quality imaging.

[0046] In summary, the second lens 2, the third lens 3, the fourth lens 4 and the fifth lens 5 are all cemented lenses. In order to further improve the clarity of the image, this embodiment reasonably allocates the effective focal lengths of the first lens 1 and the sixth lens 6 adjacent to the above-mentioned cemented lenses to the proportion of the effective focal length of the entire industrial lens, thereby achieving the effect of further improving the resolution of the industrial lens, thereby improving the clarity of the image.

[0047] Specifically, the effective focal length f1 of the first lens 1 of the industrial lens, the effective focal length f6 of the sixth lens 6, and the effective focal length f of the industrial lens satisfy the following relationship: 1.04≤|f1 / f|≤1.14; 0.75≤|f6 / f|≤0.99.

[0048] Through the above relationship, the resolving power of the industrial lens is improved, the imaging clarity is further improved, the imaging quality is guaranteed, and the optical performance of the industrial lens is optimized.

[0049] In a specific implementation of the present application, the sixth lens 6 is a biconvex positive lens, and the refractive index of the sixth lens 6 is Nd6, satisfying the following relationship: Nd6≥1.74.

[0050] By controlling the refractive index of the sixth lens 6, the imaging picture is made more uniform, thereby forming a clear image, and at the same time it helps to achieve miniaturization of the lens.

[0051] In this embodiment, the use of glass that is friendly to thermal drift can effectively improve the stability of the lens group.

[0052] The lens material of all lenses in this embodiment is glass material with a conventional refractive index, which effectively reduces the cost.

[0053] In an embodiment of the present application, the industrial lens is provided with a first lens 1, a second lens 2, a third lens 3, an aperture 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a protective glass 10 and an imaging surface 11 in sequence along the optical axis from the object side to the image side.

[0054] The first lens 1 has positive optical power, and its curved shape is conducive to the lens acquiring light at a large angle and expanding the viewing angle.

[0055] The second lens 2 is a double convex positive lens, and the third lens 3 is a double concave negative lens, which are glued together to eliminate or balance the chromatic aberration and distortion produced by the lens, reduce tolerance sensitivity, and improve imaging quality.

[0056] The aperture 9 can control the imaging quality and the stability of the optical system by limiting the propagation range and direction of the light beam.

[0057] The fourth lens 4 is a double concave negative lens, and the fifth lens 5 is a double convex positive lens, which are glued together to eliminate or balance the chromatic aberration and distortion produced by the lens, reduce tolerance sensitivity, and improve imaging quality.

[0058] At the same time, in a specific implementable manner, the fifth lens 5 reasonably controls the optical focal length so that the total optical length TTL is ≤ 60.06 mm, so as to further meet the miniaturization requirements of the lens.

[0059] The sixth lens 6 is a double convex positive lens, which is used to compress the light collected by the fifth lens 5 so that the light can smoothly transition to the rear optical system, making the picture brightness more uniform and further improving the imaging quality.

[0060] The seventh lens 7 has positive optical power and is used to focus the light collected by the sixth lens 6, which is beneficial to the field correction of the lens, optimizes the imaging performance of the lens group, and improves the imaging quality.

[0061] The eighth lens 8 is a double concave negative lens, which is used to diverge the light collected by the seventh lens 7 and correct the aberration, thereby optimizing the imaging performance of the lens group and improving the imaging quality.

[0062] In order to explain the above solution more clearly, three different embodiments that conform to the above solution are given below.

[0063] Embodiment 1: This embodiment provides a high-resolution industrial lens, such as Figure 2 As shown, in this embodiment, the first lens 1 is a meniscus positive lens convex toward the object, the second lens 2 is a double convex positive lens, the third lens 3 is a double concave negative lens, the fourth lens 4 is a double concave negative lens, the fifth lens 5 is a double convex positive lens, the sixth lens 6 is a double convex positive lens, the seventh lens 7 is a meniscus positive lens convex toward the object, and the eighth lens 8 is a double concave negative lens.

[0064] Based on the structure of the industrial lens provided above, the industrial lens includes, from the object side to the image side, a meniscus positive lens convex toward the object side, a double convex positive lens, a double concave negative lens, an aperture 9, a double concave negative lens, a double convex positive lens, a double convex positive lens, a meniscus positive lens convex toward the object side, a double concave negative lens, a protective glass 10 and an imaging surface 11, which are coaxially arranged in sequence.

[0065] Table 1 shows various parameters of multiple lenses of the industrial lens in this embodiment 1.

[0066] Table 1: Combination Figure 1 and Figure 2 As shown, the first lens 1 of this embodiment, i.e., the positive meniscus lens convex toward the object, has an object side surface S1 that is a convex surface, and an image side surface S2 that is a concave surface; The object side surface S3 of the second lens 2, i.e., the biconvex positive lens, is convex, and the image side surface S4 is convex; The object side surface S4 of the third lens 3, i.e., the double concave negative lens, is concave, and the image side surface S5 is concave; The second lens 2 and the third lens 3 are glued together and share S4, so S4 is convex relative to the second lens 2 and concave relative to the third lens 3; The fourth lens element 4, i.e., the double concave negative lens, has an object side surface S7 which is a concave surface, and an image side surface S8 which is a concave surface; The object side surface S8 of the fifth lens 5, i.e., the biconvex positive lens, is convex, and the image side surface S9 is convex; The fourth lens 4 and the fifth lens 5 are glued together and share S8, so S8 is concave relative to the fourth lens 4 and is convex relative to the fifth lens 5; The object side surface S10 of the sixth lens element 6, i.e., the biconvex positive lens, is convex, and the image side surface S11 is convex; The seventh lens element 7, i.e., a positive meniscus lens convex toward the object, has an object-side surface S12 that is convex, and an image-side surface S13 that is concave; The object side surface S14 of the eighth lens element 8, i.e., the double concave negative lens, is a concave surface, and the image side surface S15 is a concave surface; S16 and S17 are two sides of the protective glass 10; IMA is an imaging surface 11 .

[0067] In this embodiment, the parameters of the industrial lens are shown in Table 2.

[0068] Table 2: It can be seen from Table 2 above that in this embodiment, the curvature radius R of the object side surface of the fifth lens 5 is 51The curvature radius R of the image side 52 The relationship between: (R 51 -R 52 ) / R 52 =-6.6857, satisfying -6.69≤(R 51 -R 52 ) / R 52 ≤-4.05; The relationship between the total optical length TTL and the effective focal length f of an industrial lens is: TTL / f=1.7888, satisfying 1.78≤(TTL / f)≤1.81; The effective focal length f of the first cemented lens group G1 The relationship between the effective focal length f of the industrial lens and f G1 / f=-1.8666, satisfying -2.7≤(f G1 / f)≤-1.8; The effective focal length of the second cemented lens group is f G2 The relationship between the effective focal length f of the industrial lens and f G2 / f=-5.6764, satisfying -12.2≤(f G2 / f)≤-5.6; The relationship between the effective focal length f1 of the first lens 1 and the effective focal length f of the industrial lens is: |f1 / f|=1.1032, satisfying 1.04≤|f1 / f|≤1.14; The relationship between the effective focal length f6 of the sixth lens 6 and the effective focal length f of the industrial lens is: |f6 / f|=0.9825, satisfying 0.75≤|f6 / f|≤0.99; The refractive index of the sixth lens 6 is Nd6=1.7440, satisfying Nd6≥1.74.

[0069] like Figure 3 The figure shows the MTF diagram of this embodiment. 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. The imaging quality of the industrial lens from the center to the edge of the field of view is very uniform, that is, the entire image is very clear. At 60lp / mm, the optical transfer function is greater than 0.6, and the clarity of the image is guaranteed.

[0070] Figure 4 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 ±0.1mm, 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 -1.4%, indicating that the distortion of the industrial lens is well corrected, and the distortion of the imaging picture is well controlled, thereby ensuring the clarity and quality of the imaging.

[0071] Figure 5 This is a vertical chromatic aberration diagram of this embodiment, which shows the chromatic aberration of each wavelength at different image heights on the imaging surface. It can be seen from the figure that the vertical chromatic aberration of the shortest wavelength and the longest wavelength is controlled within ±0.6μm, indicating that the industrial lens can better correct the chromatic aberration of the edge field of view, has a high image color reproduction within the diffraction range, and ensures the clarity and quality of the imaging.

[0072] Figure 6 This is the axial aberration diagram of this embodiment. It can be seen from the figure that the axial aberration of the shortest wavelength and the longest wavelength is controlled within ±0.1mm, indicating that the axial aberration of the industrial lens is well corrected, ensuring the clarity and quality of the imaging.

[0073] Depend on Figure 3-Figure 6 It can be seen that this embodiment has the advantages of low distortion, low chromatic aberration, and high resolution, which ensures the clarity of imaging, can achieve better imaging effects, and has good optical performance.

[0074] Embodiment 2: This embodiment provides a high-resolution industrial lens, such as Figure 7 As shown, in this embodiment, the first lens 1 is a biconvex positive lens, the second lens 2 is a biconvex positive lens, the third lens 3 is a biconcave negative lens, the fourth lens 4 is a biconcave negative lens, the fifth lens 5 is a biconvex positive lens, the sixth lens 6 is a biconvex positive lens, the seventh lens 7 is a meniscus positive lens convex toward the object side, and the eighth lens 8 is a biconcave negative lens.

[0075] Based on the structure of the industrial lens provided above, the industrial lens includes a biconvex positive lens, a biconvex positive lens, a biconcave negative lens, an aperture 9, a biconcave negative lens, a biconvex positive lens, a biconvex positive lens, a meniscus positive lens convex toward the object side, a biconcave negative lens, a protective glass 10 and an imaging surface 11 arranged coaxially in sequence from the object side to the image side.

[0076] Table 3 shows various parameters of multiple lenses of the industrial lens in this embodiment 2.

[0077] Table 3: Combination Figure 1 and Figure 7 As shown, the object side surface S1 of the first lens 1, i.e., the biconvex positive lens of this embodiment is a convex surface, and the image side surface S2 is a convex surface; The object side surface S3 of the second lens 2, i.e., the biconvex positive lens, is convex, and the image side surface S4 is convex; The object side surface S4 of the third lens 3, i.e., the double concave negative lens, is concave, and the image side surface S5 is concave; The second lens 2 and the third lens 3 are glued together and share S4, so S4 is convex relative to the second lens 2 and concave relative to the third lens 3; The fourth lens element 4, i.e., the double concave negative lens, has an object side surface S7 which is a concave surface, and an image side surface S8 which is a concave surface; The object side surface S8 of the fifth lens 5, i.e., the biconvex positive lens, is convex, and the image side surface S9 is convex; The fourth lens 4 and the fifth lens 5 are glued together and share S8, so S8 is concave relative to the fourth lens 4 and is convex relative to the fifth lens 5; The object side surface S10 of the sixth lens element 6, i.e., the biconvex positive lens, is convex, and the image side surface S11 is convex; The seventh lens element 7, i.e., a positive meniscus lens convex toward the object, has an object-side surface S12 that is convex, and an image-side surface S13 that is concave; The object side surface S14 of the eighth lens element 8, i.e., the double concave negative lens, is a concave surface, and the image side surface S15 is a concave surface; S16 and S17 are two sides of the protective glass 10; IMA is an imaging surface 11 .

[0078] In this embodiment, the parameters of the industrial lens are shown in Table 4.

[0079] Table 4: <![CDATA[f G1 ]]> -71.8084 <![CDATA[f G2 ]]> -397.4813 f 32.6501 <![CDATA[f1]]> 33.995117 <![CDATA[f6]]> 24.596693 TTL 58.4751 <![CDATA[R 51 ]]> 83.5233 <![CDATA[R 52 ]]> -17.9243 <![CDATA[Nd6]]> 1.7440 It can be seen from Table 4 above that in this embodiment, the curvature radius R of the object side surface of the fifth lens 5 is 51 The curvature radius R of the image side 52 The relationship between: (R 51 -R 52 ) / R 52 =-5.6598, satisfying -6.69≤(R 51 -R 52 ) / R 52 ≤-4.05; The relationship between the total optical length TTL and the effective focal length f of an industrial lens is: TTL / f=1.7910, satisfying 1.78≤(TTL / f)≤1.81; The effective focal length f of the first cemented lens group G1 The relationship between the effective focal length f of the industrial lens and f G1 / f=-2.1993, satisfying -2.7≤(f G1 / f)≤-1.8; The effective focal length of the second cemented lens group is f G2 The relationship between the effective focal length f of the industrial lens and f G2 / f=-12.1740, satisfying -12.2≤(f G2 / f)≤-5.6; The relationship between the effective focal length f1 of the first lens 1 and the effective focal length f of the industrial lens is: |f1 / f|=1.0412, satisfying 1.04≤|f1 / f|≤1.14; The relationship between the effective focal length f6 of the sixth lens 6 and the effective focal length f of the industrial lens is: |f6 / f|=0.7533, satisfying 0.75≤|f6 / f|≤0.99; The refractive index of the sixth lens 6 is Nd6=1.7440, satisfying Nd6≥1.74.

[0080] like Figure 8 The figure shows the MTF diagram of this embodiment. 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. The imaging quality of the industrial lens from the center to the edge of the field of view is very uniform, that is, the entire image is very clear. At 60lp / mm, the optical transfer function is greater than 0.65, and the clarity of the image is guaranteed.

[0081] Fig. 9 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 ±0.08mm, 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 0.08%, indicating that the distortion of the industrial lens is well corrected, and the distortion of the imaging picture is well controlled, thereby ensuring the clarity and quality of the imaging.

[0082] Fig.10 This is the vertical chromatic aberration diagram of this embodiment, which shows the chromatic aberration of each wavelength at different image heights on the imaging surface. It can be seen from the figure that the vertical chromatic aberration of the shortest wavelength and the longest wavelength is controlled within ±2.5μm, indicating that the industrial lens can better correct the chromatic aberration of the edge field of view, has a high image color reproduction within the diffraction range, and ensures the clarity and quality of the imaging.

[0083] Fig.11 This is the axial aberration diagram of this embodiment. It can be seen from the figure that the axial aberration of the shortest wavelength and the longest wavelength is controlled within ±0.08mm, indicating that the axial aberration of the industrial lens is well corrected, ensuring the clarity and quality of the imaging.

[0084] Depend on Figure 8-Figure 11 It can be seen that this embodiment has the advantages of low distortion, low chromatic aberration, and high resolution, which ensures the clarity of imaging, can achieve better imaging effects, and has good optical performance.

[0085] Embodiment 3: This embodiment provides a high-resolution industrial lens, such as Fig.12As shown, in this embodiment, the first lens 1 is a biconvex positive lens, the second lens 2 is a biconvex positive lens, the third lens 3 is a biconcave negative lens, the fourth lens 4 is a biconcave negative lens, the fifth lens 5 is a biconvex positive 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.

[0086] Based on the structure of the industrial lens provided above, the industrial lens includes a biconvex positive lens, a biconvex positive lens, a biconcave negative lens, an aperture 9, a biconcave negative lens, a biconvex positive lens, a biconvex positive lens, a biconvex positive lens, a biconvex positive lens, a biconcave negative lens, a protective glass 10 and an imaging surface 11 arranged coaxially in sequence from the object side to the image side.

[0087] Table 5 shows various parameters of multiple lenses of the industrial lens in this embodiment 3.

[0088] Table 5: Combination Figure 1 and Fig.12 As shown, the object side surface S1 of the first lens 1, i.e., the biconvex positive lens of this embodiment is a convex surface, and the image side surface S2 is a convex surface; The object side surface S3 of the second lens 2, i.e., the biconvex positive lens, is convex, and the image side surface S4 is convex; The object side surface S4 of the third lens 3, i.e., the double concave negative lens, is concave, and the image side surface S5 is concave; The second lens 2 and the third lens 3 are glued together and share S4, so S4 is convex relative to the second lens 2 and concave relative to the third lens 3; The fourth lens element 4, i.e., the double concave negative lens, has an object side surface S7 which is a concave surface, and an image side surface S8 which is a concave surface; The object side surface S8 of the fifth lens 5, i.e., the biconvex positive lens, is convex, and the image side surface S9 is convex; The fourth lens 4 and the fifth lens 5 are glued together and share S8, so S8 is concave relative to the fourth lens 4 and is convex relative to the fifth lens 5; The object side surface S10 of the sixth lens element 6, i.e., the biconvex positive lens, is convex, and the image side surface S11 is convex; The object side surface S12 of the seventh lens element 7, i.e., the biconvex positive lens, is convex, and the image side surface S13 is convex; The object side surface S14 of the eighth lens element 8, i.e., the double concave negative lens, is a concave surface, and the image side surface S15 is a concave surface; S16 and S17 are two sides of the protective glass 10; IMA is an imaging surface 11 .

[0089] In this embodiment, the parameters of the industrial lens are shown in Table 6.

[0090] Table 6: <![CDATA[f G1 ]]> -85.2346 <![CDATA[f G2 ]]> -190.5752 f 32.5526 <![CDATA[f1]]> 36.820647 <![CDATA[f6]]> 29.840537 TTL 58.6601 <![CDATA[R 51 ]]> 64.1769 <![CDATA[R 52 ]]> -21.0113 <![CDATA[Nd6]]> 1.7440 It can be seen from Table 6 above that in this embodiment, the curvature radius R of the object side surface of the fifth lens 5 is 51 The curvature radius R of the image side 52 The relationship between: (R 51 -R 52 ) / R 52 =-4.0544, satisfying -6.69≤(R 51 -R 52 ) / R 52 ≤-4.05; The relationship between the total optical length TTL and the effective focal length f of an industrial lens is: TTL / f=1.8020, satisfying 1.78≤(TTL / f)≤1.81; The effective focal length f of the first cemented lens group G1 The relationship between the effective focal length f of the industrial lens and f G1 / f=-2.6184, satisfying -2.7≤(f G1 / f)≤-1.8; The effective focal length of the second cemented lens group is f G2 The relationship between the effective focal length f of the industrial lens and f G2 / f=-5.8544, satisfying -12.2≤(f G2 / f)≤-5.6; The relationship between the effective focal length f1 of the first lens 1 and the effective focal length f of the industrial lens is: |f1 / f|=1.1311, satisfying 1.04≤|f1 / f|≤1.14; The relationship between the effective focal length f6 of the sixth lens 6 and the effective focal length f of the industrial lens is: |f6 / f|=0.9167, satisfying 0.75≤|f6 / f|≤0.99; The refractive index of the sixth lens 6 is Nd6=1.7440, satisfying Nd6≥1.74.

[0091] like Fig.13 The figure shows the MTF diagram of this embodiment. 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. The imaging quality of the industrial lens from the center to the edge of the field of view is very uniform, that is, the entire image is very clear. At 60lp / mm, the optical transfer function is greater than 0.6, and the clarity of the image is guaranteed.

[0092] Fig.14This 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 ±0.1mm, 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 0.05%, indicating that the distortion of the industrial lens is well corrected, and the distortion of the imaging picture is well controlled, thereby ensuring the clarity and quality of the imaging.

[0093] Fig.15 This is the vertical chromatic aberration diagram of this embodiment, which shows the chromatic aberration of each wavelength at different image heights on the imaging surface. It can be seen from the figure that the vertical chromatic aberration of the shortest wavelength and the longest wavelength is controlled within ±2μm, indicating that the industrial lens can better correct the chromatic aberration of the edge field of view, has a high image color reproduction within the diffraction range, and ensures the clarity and quality of the imaging.

[0094] Fig.16 This is the axial aberration diagram of this embodiment. It can be seen from the figure that the axial aberration of the shortest wavelength and the longest wavelength is controlled within ±0.1mm, indicating that the axial aberration of the industrial lens is well corrected, ensuring the clarity and quality of the imaging.

[0095] Depend on Figure 13-Figure 16 It can be seen that this embodiment has the advantages of low distortion, low chromatic aberration, and high resolution, which ensures the clarity of imaging, can achieve better imaging effects, and has good optical performance.

[0096] 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. A high-resolution industrial lens, characterized by: The invention comprises a plurality of lenses, wherein the plurality of lenses are 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) which are coaxially arranged in sequence from the object side to the image side, and each of the lenses has an object side surface facing the object side and an image side surface facing the image side; An aperture (9) is provided between the third lens (3) and the fourth lens (4), and the aperture (9) is coaxially arranged with the plurality of lenses; The first lens (1), the second lens (2), the fifth lens (5), the sixth lens (6) and the seventh lens (7) have positive optical power, and the third lens (3), the fourth lens (4) and the eighth lens (8) have negative optical power; Industrial lenses satisfy the following relationship: -6.69≤(R 51 -R 52 ) / R 52 ≤-4.05; 78≤(TTL / f)≤1.81; Among them, R 51 is the radius of curvature of the object side surface of the fifth lens (5), R 52 is the radius of curvature of the image side surface of the fifth lens (5), TTL is the total optical length of the industrial lens, and f is the effective focal length of the industrial lens.

2. The high-resolution industrial lens according to claim 1, characterized in that: The second lens (2) is a double convex positive lens, the third lens (3) is a double concave negative lens, and the second lens (2) and the third lens (3) form a first cemented lens group.

3. The high-resolution industrial lens according to claim 2, characterized in that: The industrial lens also satisfies the following relationship: -2.7≤(f G1 / f)≤-1.8; Among them, f G1 is the effective focal length of the first cemented lens group.

4. The high-resolution industrial lens according to claim 1, characterized in that: The fourth lens (4) is a double concave negative lens, the fifth lens (5) is a double convex positive lens, and the fourth lens (4) and the fifth lens (5) form a second cemented lens group.

5. The high-resolution industrial lens according to claim 4, characterized in that: The industrial lens also satisfies the following relationship: -12.2≤(f G2 / f)≤-5.6; Among them, f G2 is the effective focal length of the second cemented lens group.

6. The high-resolution industrial lens according to claim 1, characterized in that: The industrial lens also satisfies the following relationship: 04≤|f1 / f|≤1.14; 75≤|f6 / f|≤0.99; Wherein, f1 is the effective focal length of the first lens (1), and f6 is the effective focal length of the sixth lens (6).

7. The high-resolution industrial lens according to claim 1, characterized in that: The sixth lens (6) is a biconvex positive lens, and the refractive index of the sixth lens (6) is Nd6, satisfying the following relationship: Nd6≥1.

74.

8. The high-resolution industrial lens according to claim 1, characterized in that: The first lens (1) is a positive meniscus lens convex toward the object, the seventh lens (7) is a positive meniscus lens convex toward the object, and the eighth lens (8) is a double concave negative lens.

9. The high-resolution industrial lens according to claim 1, characterized in that: The first lens (1) is a double convex positive lens, the seventh lens (7) is a meniscus positive lens convex toward the object, and the eighth lens (8) is a double concave negative lens.

10. The high-resolution industrial lens according to claim 1, characterized in that: The first lens (1) is a biconvex positive lens, the seventh lens (7) is a biconvex positive lens, and the eighth lens (8) is a biconcave negative lens.

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