An industrial lens and an optical device

Abstract

The present application discloses an industrial lens and an optical device. Among them, an industrial lens includes a first lens group, a diaphragm, and a second lens group that are coaxially arranged in sequence. The first lens group includes a first lens, a second lens, a third lens, and a fourth lens that are arranged in sequence from the object side to the image side along the optical axis. The first lens, the second lens, and the fourth lens have positive optical powers, and the third lens has a negative optical power. The second lens group includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens that are arranged in sequence from the object side to the image side along the optical axis. The fifth lens, the seventh lens, and the eighth lens have positive optical powers, and the sixth lens has a negative optical power. The industrial lens satisfies the following relational expressions: 4.3 ≤ FOV / CRA ≤ 5.6; 13 ≤ (f u1 + f u2 ) / IH ≤ 26; FOV / (D * TTL) ≥ 0.025; where FOV is the maximum field of view angle of the industrial lens, CRA is the chief ray angle of incidence of the industrial lens, 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, IH is the maximum image plane height of the industrial lens, D is the head aperture size of the industrial lens, and TTL is the overall optical length of the industrial lens. The present application realizes a miniaturized industrial lens with a large image plane, low distortion, low chromatic aberration, and high resolution.

Description

Technical Field

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

[0002] As one of the core components of industrial automation systems, industrial lenses are the most advanced components for acquiring image data. They play a decisive role in the accuracy of information acquisition and play a vital role in machine vision systems. Given the particularity of industrial requirements, industrial lenses often need to have higher performance than ordinary lenses, especially in terms of image quality and size. High-precision, high-resolution industrial lenses can help industrial equipment better complete complex tasks, improve product quality and production efficiency, and thus achieve the goal of intelligent manufacturing. Although there are some high-performance industrial lenses on the market, there are still many shortcomings in practical applications.

[0003] Existing industrial lens design solutions usually focus on improving performance in one aspect, such as imaging resolution or miniaturization, but it is difficult to take into account the needs of many aspects. Although they can provide a larger imaging target area, due to the limitations of structural design, there are common problems such as imaging distortion and large size, which makes it difficult for the lens to meet actual needs in application scenarios with high precision requirements, limiting the further improvement and development of industrial automation.

[0004] In response to the above requirements, existing industrial lenses still have certain deficiencies and defects, especially the inability to ensure excellent image quality while ensuring that the entire industrial lens has a larger imaging target surface and good portability. Therefore, how to achieve miniaturization, large target surface and low distortion of industrial lenses while ensuring imaging quality has become a key issue that needs to be solved in this field. Summary of the invention

[0005] In order to achieve the requirements of large image surface, low distortion and miniaturized lenses, meet the high precision and high resolution of industrial lenses, and further improve industrial automation, the present application provides an industrial lens and optical equipment.

[0006] In the first aspect, the present application provides an industrial lens, which adopts the following technical solution:

[0007] An industrial lens, comprising a first lens group, an aperture, and a second lens group coaxially arranged in sequence, wherein the first lens group comprises a first lens, a second lens, a third lens, and a fourth lens arranged in sequence from the object side to the image side along the optical axis, wherein the first lens, the second lens, and the fourth lens have positive optical power, and the third lens has negative optical power;

[0008] The second lens group includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens sequentially arranged along the optical axis from the object side to the image side. The fifth lens, the seventh lens, and the eighth lens have positive optical powers, and the sixth lens has a negative optical power;

[0009] The industrial lens satisfies the following relational expressions,

[0010] 4.3 ≤ FOV / CRA ≤ 5.6;

[0011] 13 ≤ (f u1 + f u2 ) / IH ≤ 26;

[0012] FOV / (D * TTL) ≥ 0.025;

[0013] Wherein, FOV is the maximum field of view angle of the industrial lens, CRA is the chief ray angle of incidence of the industrial lens, 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, IH is the maximum image plane height of the industrial lens, D is the head aperture size of the industrial lens, and TTL is the total optical length of the industrial lens.

[0014] By adopting the above technical solutions, the relationship between the maximum field of view angle and the chief ray angle of incidence of the industrial lens is controlled, the positions of the lenses in the industrial lens group are reasonably distributed to ensure the minimum distortion of the industrial lens; by reasonably distributing the optical powers of the first lens group and the second lens group, the requirement of large target surface imaging of the industrial lens is realized; by controlling the relationship among the maximum field of view angle, the head aperture size, and the total optical length of the industrial lens, the miniaturization of the industrial lens is realized.

[0015] Preferably, the first lens and the second lens are meniscus positive lenses convex toward the object side, the third lens is a biconcave negative lens, the fourth lens is a biconvex positive lens, the fifth lens is a plano-convex positive lens, the sixth lens is a biconcave negative lens, the seventh lens is a meniscus positive lens convex toward the image side, and the eighth lens is a biconvex positive lens.

[0016] Preferably, the first lens 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, the fourth lens is a biconvex positive lens, the fifth lens is a meniscus positive lens convex toward the image side, the sixth lens is a biconcave negative lens, the seventh lens is a meniscus positive lens convex toward the image side, and the eighth lens is a biconvex positive lens.

[0017] Preferably, the first lens 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, the fourth lens is a biconvex positive lens, the fifth lens is a biconvex positive lens, the sixth lens is a biconcave negative lens, the seventh lens is a meniscus positive lens convex toward the image side, and the eighth lens is a biconvex positive lens.

[0018] By adopting the above technical solutions, three implementable lens shapes of each lens in the industrial lens are given, providing a basis for the specific implementation of this solution.

[0019] Preferably, the industrial lens also satisfies the following relational expressions

[0020] |f u1 / f| ≤ 8.1;

[0021] |f u2 / f| ≥ 0.86;

[0022] where f is the effective focal length of the industrial lens.

[0023] By adopting the above technical solutions, the proportions of the optical powers of the first lens group and the second lens group to the optical power of the entire lens are reasonably allocated, meeting the requirement of high resolution and ensuring the clarity of imaging.

[0024] Preferably, the fifth lens and the sixth lens are doublet lenses and are glass lenses.

[0025] By adopting the above technical solutions, the aberration of the optical lens is corrected using the doublet lens, eliminating or balancing the chromatic aberration generated by the lens, reducing the tolerance sensitivity, and improving the imaging resolution of the optical imaging lens; moreover, the glass lens can effectively improve the stability and durability of the lens group.

[0026] Preferably, the industrial lens also satisfies the following relational expressions

[0027] 35 ≤ |VD5 - VD6| ≤ 43,

[0028] where VD5 is the Abbe number of the fifth lens and VD6 is the Abbe number of the sixth lens.

[0029] By adopting the above technical solutions, the Abbe numbers of the fifth lens and the sixth lens that make up the doublet lens are reasonably selected, which can effectively reduce the chromatic aberration of the optical system.

[0030] Preferably, the industrial lens also satisfies the following relational expressions

[0031] Nd4 ≥ 1.8,

[0032] where Nd4 is the refractive index of the lens material of the fourth lens in the industrial lens at the Fraunhofer spectral line.

[0033] By adopting the above technical solution, controlling the refractive index of the fourth lens helps to miniaturize the industrial lens.

[0034] Preferably, the industrial lens further satisfies the following relational expressions:

[0035] Nd5 ≤ 1.7;

[0036] VD5 ≥ 63;

[0037] where Nd5 is the refractive index of the lens material of the fifth lens in the industrial lens at the Fraunhofer spectral line, and VD5 is the Abbe number of the fifth lens.

[0038] By adopting the above technical solution, using glass that is friendly to thermal drift as the material of the fifth lens can effectively improve the stability of the lens group.

[0039] In a second aspect, an optical device provided by the present application adopts the following technical solution:

[0040] An optical device includes the industrial lens described in any one of the above.

[0041] In summary, the present application has at least the following beneficial effects:

[0042] (1) By controlling the maximum field of view angle and the chief ray incident angle, and reasonably distributing the positions of the lenses in the industrial lens, the present application meets the requirement of low distortion while maintaining the optical performance of the lens.

[0043] (2) By introducing a cemented lens into the imaging system and controlling the Abbe number of the cemented lens, the present application optimizes the optical performance, reduces the chromatic aberration of imaging, improves the imaging resolution, and ensures the stability of the lens.

[0044] (3) By dividing the industrial lens into a first lens group and a second lens group and reasonably distributing their optical powers, the present application can achieve large target surface imaging of the optical system while maintaining the imaging clarity.

[0045] (4) By controlling the relationship among the maximum field of view angle, the head aperture size, and the overall optical length of the industrial lens, the present application miniaturizes the industrial lens. Description of the Drawings

[0046] Figure 1 is a lens configuration diagram of an industrial lens according to an embodiment of the present application;

[0047] Figure 2 is a schematic optical path diagram of Embodiment 1 of the present application;

[0048] Figure 3 is the modulation transfer function graph of Embodiment 1 of the present application;

[0049] Figure 4 is the schematic diagram of field curvature / F - Tan(θ) distortion of Embodiment 1 of the present application;

[0050] Figure 5 is the schematic diagram of lateral chromatic aberration of Embodiment 1 of the present application;

[0051] Figure 6 is the axial aberration curve graph of Embodiment 1 of the present application;

[0052] Figure 7 is the optical path schematic diagram of Embodiment 2 of the present application;

[0053] Figure 8 is the modulation transfer function graph of Embodiment 2 of the present application;

[0054] Figure 9 is the schematic diagram of field curvature / F - Tan(θ) distortion of Embodiment 2 of the present application;

[0055] Figure 10 is the schematic diagram of lateral chromatic aberration of Embodiment 2 of the present application;

[0056] Figure 11 is the axial aberration curve graph of Embodiment 2 of the present application;

[0057] Figure 12 is the optical path schematic diagram of Embodiment 3 of the present application;

[0058] Figure 13 is the modulation transfer function graph of Embodiment 3 of the present application;

[0059] Figure 14 is the schematic diagram of field curvature / F - Tan(θ) distortion of Embodiment 3 of the present application;

[0060] Figure 15 is the schematic diagram of lateral chromatic aberration of Embodiment 3 of the present application;

[0061] Figure 16 is the axial aberration curve graph of Embodiment 3 of the present application.

[0062] Explanation of reference numerals:

[0063] 1. First lens group; 2. Diaphragm; 3. Second lens group; 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. Imaging surface. Detailed implementation manners

[0064] This application provides an industrial lens and an optical device. To make the objectives, technical solutions, and advantages of this application clearer, the following will further elaborate on the implementation manners of this application in detail.

[0065] The following will clearly and completely describe the technical solutions in some embodiments of this application with reference to the accompanying drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of them.

[0066] It should be noted that in this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0067] This application proposes an industrial lens, as Figure 1 shown, including a first lens group 1, a diaphragm 2, a second lens group 3, and an imaging surface 12 arranged coaxially in sequence. The first lens group 1 includes a first lens 4, a second lens 5, a third lens 6, and a fourth lens 7 arranged in sequence along the optical axis from the object side to the image side. The first lens 4, the second lens 5, and the fourth lens 7 have positive optical powers, and the third lens 6 has a negative optical power;

[0068] The second lens group 3 includes a fifth lens 8, a sixth lens 9, a seventh lens 10, and an eighth lens 11 arranged in sequence along the optical axis from the object side to the image side. The fifth lens 8, the seventh lens 10, and the eighth lens 11 have positive optical powers, and the sixth lens 9 has a negative optical power;

[0069] The industrial lens satisfies the following relationships,

[0070] 4.3 ≤ FOV / CRA ≤ 5.6;

[0071] 13 ≤ (f u1 + f u2 ) / IH ≤ 26;

[0072] FOV / (D * TTL) ≥ 0.025;

[0073] wherein, FOV is the maximum field of view angle of the industrial lens, CRA is the chief ray angle of incidence of the industrial lens, 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 3 in the industrial lens, IH is the maximum image plane height of the industrial lens, D is the head aperture size of the industrial lens, and TTL is the optical total length of the industrial lens, that is, the distance from the center of the object side surface of the first lens 4 to the imaging surface 12.

[0074] In some embodiments of the present application, the entire industrial lens is divided into two lens groups, a front lens group and a rear lens group, in the direction from the object to the image. The front lens group closer to the object side is the first lens group 1, and the rear lens group closer to the image side is the second lens group 3. The two lens groups are separated by a diaphragm 2 (i.e., ST0). The diaphragm 2 controls the imaging quality and the performance of the optical system by restricting the propagation range and direction of the light beam. Reasonably distributing the optical power of the front lens group and the rear lens group can achieve large target surface imaging of the optical system.

[0075] Through the above relationships, the industrial lens can ensure the clarity of imaging while achieving large target surface imaging, and at the same time, the industrial lens can be made smaller.

[0076] In an embodiment of the present application, the optical power f u1 of the first lens group 1 and the optical power f u2 of the second lens group 3 respectively satisfy the following relationships with the effective focal length f of the entire industrial lens:

[0077] |f u1 / f| ≤ 8.1;

[0078] |f u2 / f| ≥ 0.86.

[0079] Through the above ratio constraints, the requirements of the industrial lens for high resolution are met, and the clarity of imaging is ensured.

[0080] In an embodiment of the present application, the fifth lens 8 and the sixth lens 9 are double - glued lenses and are glass lenses. The glued lenses can correct the aberration of the lens, balance the chromatic aberration generated by the lens, and improve the imaging resolution. Using glass material can effectively improve the stability and durability of the lens group.

[0081] In an embodiment of the present application, the Abbe number VD5 of the double - glued lens fifth lens 8 and the Abbe number VD6 of the sixth lens 9 satisfy the following relationship:

[0082] 35 ≤ |VD5 - VD6| ≤ 43,

[0083] Controlling the Abbe number of the glued lens within the above range can effectively reduce the chromatic aberration of the optical system.

[0084] In an embodiment of the present application, the refractive index Nd5 of the glued lens fifth lens 8 and the Abbe number VD5 of the fifth lens 8 satisfy the following relationship:

[0085] Nd5 ≤ 1.7;

[0086] VD5 ≥ 63;

[0087] Controlling the Abbe number of the fifth lens 8 further improves the imaging clarity. Moreover, using glass that is friendly to thermal drift for the fifth lens 8 can effectively improve the stability of the lens group.

[0088] In the embodiment of the present application, the refractive index Nd4 of the fourth lens 7 at the Fraunhofer spectral line also satisfies the following relational expression: Nd4 ≥ 1.8.

[0089] Materials with high refractive index can be used to control the refractive index of the fourth lens, which helps to miniaturize the industrial lens.

[0090] In the embodiment of the present application, an industrial lens is sequentially provided with a first lens 4, a second lens 5, a third lens 6, a fourth lens 7, a diaphragm 2, a fifth lens 8, a sixth lens 9, a seventh lens 10, an eighth lens 11, and an imaging surface 12 along the optical axis from the object side to the image side.

[0091] Among them, the first lens 4 has a positive optical power, and its bending shape is beneficial for the industrial lens to capture light at large angles; the second lens 5 has a positive optical power and can compress the light collected by the first lens 4, enabling the light to transition smoothly to the subsequent optical system, which is beneficial for more uniform picture brightness.

[0092] The third lens 6 has a negative optical power and can diverge the light collected by the second lens 5, enabling the light to transition smoothly to the subsequent optical system and reasonably controlling the optical power.

[0093] The fourth lens 7 has a positive optical power and can focus the light collected by the third lens 6, making the light irradiate the target area more evenly.

[0094] Moreover, by reasonably controlling the optical power, the fourth lens 7 can make TTL ≤ 59.53 mm to meet the miniaturization requirements.

[0095] The diaphragm 2 is placed between the fourth lens 7 and the fifth lens 8, and controls the imaging quality and the performance of the optical system by restricting the propagation range and direction of the light beam.

[0096] The fifth lens 8 and the sixth lens 9 are doublet lenses, which are used to eliminate or balance the chromatic aberration and distortion generated by the lens and reduce the tolerance sensitivity.

[0097] Among them, the fifth lens 8 has a positive optical power, the sixth lens 9 has a negative optical power, and both are glass lenses, which can effectively improve the stability and durability of the lens group.

[0098] The seventh lens 10 has a positive optical power, can focus the light collected by the doublet lens, and corrects the aberration to optimize the imaging performance of the lens group.

[0099] The eighth lens 11 has a positive optical power and can focus the light rays collected by the seventh lens 10, which is beneficial to the field correction of the lens and optimizes the imaging performance of the lens group.

[0100] The following are three different embodiments of industrial lenses that meet the above solutions as specific implementation manners of the present application.

[0101] Embodiment 1:

[0102] This embodiment provides an industrial lens. As Figure 2 shown, in Embodiment 1, the first lens 4 and the second lens 5 are meniscus positive lenses convex toward the object side, the third lens 6 is a biconcave negative lens, the fourth lens 7 is a biconvex positive lens, the fifth lens 8 is a plano-convex positive lens, the sixth lens 9 is a biconcave negative lens, the seventh lens 10 is a meniscus positive lens convex toward the image side, and the eighth lens 11 is a biconvex positive lens.

[0103] Based on the structure of the industrial lens provided in the above Embodiment 1, in the industrial lens including a meniscus positive lens convex toward the object side, a meniscus positive lens convex toward the object side, a biconcave negative lens, a biconvex positive lens, a diaphragm 2, a plano-convex positive lens, a biconcave negative lens, a meniscus positive lens convex toward the image side, a biconvex positive lens, and an imaging surface 12 arranged coaxially in sequence, Table 1 shows the parameters of various lenses of the industrial lens.

[0104] Table 1:

[0105]

[0106]

[0107] Combined with Figure 1 and Figure 2 shown, the object side surface S1 of the first lens 4, i.e., the meniscus positive lens, is convex, and the image side surface S2 is concave;

[0108] The object side surface S3 of the second lens 5, i.e., the meniscus positive lens, is convex, and the image side surface S4 is concave;

[0109] The object side surface S5 of the third lens 6, i.e., the biconcave negative lens, is concave, and the image side surface S6 is concave;

[0110] The object side surface S7 of the fourth lens 7, i.e., the biconvex positive lens, is convex, and the image side surface S8 is convex;

[0111] The object side surface S10 of the fifth lens 8, i.e., the plano-convex positive lens, is flat, and the image side surface S11 is convex;

[0112] The object side surface S11 of the sixth lens 9, i.e., the biconcave negative lens, is concave, and the image side surface S12 is concave;

[0113] The fifth lens 8 and the sixth lens 9 are cemented lenses and share S11. Therefore, S11 is convex with respect to the fifth lens 8 and concave with respect to the sixth lens 9;

[0114] The object side S13 of the seventh lens 10, which is a meniscus positive lens, is concave, and the image side S14 is convex;

[0115] The object side S15 of the eighth lens 11, which is a biconvex positive lens, is convex, and the image side S16 is convex;

[0116] IMA is the imaging surface.

[0117] In this embodiment 1, the parameters of the industrial lens are shown in Table 2.

[0118] Table 2:

[0119]

[0120]

[0121] As can be seen from the above Table 2, in this embodiment 1, the relationship between the maximum field of view FOV of the industrial lens and the chief ray angle of incidence CRA of the industrial lens is: FOV / CRA = 4.3886, satisfying the relation 4.3 ≤ FOV / CRA ≤ 5.6;

[0122] The effective focal length f of the first lens group 1 u1 , the effective focal length f of the second lens group 3 u2 , and the maximum image height IH are related as follows: (f u1 + f u2 ) / IH = 13.0632, satisfying the relation 13 ≤ (f u1 + f u2 ) / IH ≤ 26;

[0123] The relationship between the maximum field of view FOV, the head aperture size D, and the overall optical length TTL of the industrial lens is: TTLFOV / (D*TTL) = 0.0299, satisfying the relation FOV / (D*TTL) ≥ 0.025;

[0124] The optical power f of the first lens group 1 u1 , and the relationship with the effective focal length f of the entire industrial lens is: |f u1 / f| = 3.5230, satisfying the relation |f u1 / f| ≤ 8.1;

[0125] The optical power f of the second lens group 3 u2 , and the relationship with the effective focal length f of the entire industrial lens is: |f u2 / f| = 1.1793, satisfying the relation |f u2 / f| ≥ 0.86;

[0126] The relationship between the Abbe number VD5 of the fifth lens 8 and the Abbe number VD6 of the sixth lens 9: |VD5 - VD6| = 42.6579, satisfying the relational expression 35 ≤ |VD5 - VD6| ≤ 43;

[0127] The refractive index Nd5 of the fifth lens 8 is 1.4875, satisfying Nd5 ≤ 1.7;

[0128] The Abbe number VD5 of the fifth lens 8 is 70.4196, satisfying VD5 ≥ 63;

[0129] The refractive index Nd4 of the fourth lens 7 is 1.8348, Nd4 ≥ 1.8.

[0130] The Modulation Transfer Function (MTF) graph of Embodiment 1 is as Figure 3 shown. Taking the distance from the image field center to the image field edge as the abscissa, it reflects the imaging quality at the lens edge. It can be seen that the imaging quality of the industrial lens is very uniform from the center to the edge of the field of view, that is, the entire image is very clear, and the imaging clarity is guaranteed.

[0131] The MTF curve generated by the line parallel to the diameter is called the sagittal curve, labeled as the S (Sagittal) curve, and the MTF curve generated by the line parallel to the tangent is called the meridional curve, labeled as the T (Meridional) curve. Figure 3 There are multiple groups of MTF change curves from the image field center to the image field edge, reflecting that this industrial lens has a high resolution.

[0132] The field curvature / F - Tan(θ) distortion schematic diagram of Embodiment 1 is as Figure 4 shown. The left part is the schematic diagram of field curvature, where the abscissa represents the magnitude of field curvature, in mm, and the ordinate represents the image height. In the figure, both the meridional field curvature value and the sagittal field curvature value are controlled within ±0.1 mm, indicating that the field curvature of the industrial lens has been well corrected; the right part is the schematic diagram of distortion, where the abscissa represents the magnitude of distortion, in percentage, and the ordinate represents the image height. It can be seen from the figure that the F - Tan(θ) distortion value is controlled within -1%, indicating that the distortion of the industrial lens has been well corrected.

[0133] The schematic diagram of lateral chromatic aberration of Embodiment 1 is as Figure 5 shown, Figure 5 where the abscissa represents the magnitude of lateral chromatic aberration, in um, and the ordinate represents the image height. It represents the chromatic aberration at different image heights on the imaging plane for each wavelength. The horizontal axis represents the offset amount, in μm, and the vertical axis represents the object height, in mm. From Figure 5It can be seen that the vertical chromatic aberration between the shortest wavelength and the longest wavelength is controlled within ±2.5 μm, indicating that the industrial lens can correct the chromatic aberration of the edge field of view well.

[0134] The axial aberration curve of Embodiment 1 is as Figure 6 shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the offset, with the unit of mm, and the vertical axis represents the normalized pupil radius. From Figure 6 it can be seen that the axial aberration between the shortest wavelength and the longest wavelength is controlled within ±0.06 mm, indicating that the axial aberration of the industrial lens has been well corrected.

[0135] From Figures 3 - 6 it can be seen that this industrial lens has low distortion, low chromatic aberration, and high resolution, and can achieve better imaging effects.

[0136] Embodiment 2:

[0137] This embodiment provides an industrial lens, as Figure 7 shown. In Embodiment 2, the first lens 4 is a biconvex positive lens, the second lens 5 is a meniscus positive lens convex toward the object side, the third lens 6 is a biconcave negative lens, the fourth lens 7 is a biconvex positive lens, the fifth lens 8 is a meniscus positive lens convex toward the image side, the sixth lens 9 is a biconcave negative lens, the seventh lens 10 is a meniscus positive lens convex toward the image side, and the eighth lens 11 is a biconvex positive lens.

[0138] Based on the structure of the industrial lens provided in the above Embodiment 2, in the industrial lens including a biconvex positive lens, a meniscus positive lens convex toward the object side, a biconcave negative lens, a biconvex positive lens, a diaphragm 2, a meniscus positive lens convex toward the image side, a biconcave negative lens, a meniscus positive lens convex toward the image side, a biconvex positive lens, and an imaging plane 12 arranged coaxially in sequence, Table 3 shows the parameters of each of the multiple lenses of the industrial lens.

[0139] Table 3:

[0140]

[0141]

[0142] Combined with Figure 1 and Figure 7 shown, the object side surface S1 of the first lens 4, i.e., the biconvex positive lens, is a convex surface, and the image side surface S2 is a convex surface;

[0143] The object side surface S3 of the second lens 5, i.e., the meniscus positive lens, is a convex surface, and the image side surface S4 is a concave surface;

[0144] The object side surface S5 of the third lens 6, i.e., the biconcave negative lens, is a concave surface, and the image side surface S6 is a concave surface;

[0145] The object side S7 of the fourth lens 7, which is a biconvex positive lens, is convex, and the image side S8 is convex;

[0146] The object side S10 of the fifth lens 8, which is a meniscus positive lens, is concave, and the image side S11 is convex;

[0147] The object side S11 of the sixth lens 9, which is a biconcave negative lens, is concave, and the image side S12 is concave;

[0148] The fifth lens 8 and the sixth lens 9 are cemented lenses and share S11. Therefore, S11 is convex with respect to the fifth lens 8 and concave with respect to the sixth lens 9;

[0149] The object side S13 of the seventh lens 10, which is a meniscus positive lens, is concave, and the image side S14 is convex;

[0150] The object side S15 of the eighth lens 11, which is a biconvex positive lens, is convex, and the image side S16 is convex;

[0151] IMA is the imaging surface.

[0152] In the present Embodiment 2, the parameters of the industrial lens are shown in Table 4.

[0153] Table 4:

[0154]

[0155]

[0156] As can be seen from Table 4 above, in the present Embodiment 2, the relationship between the maximum field of view FOV of the industrial lens and the chief ray angle of incidence CRA of the industrial lens is: FOV / CRA = 4.7531, satisfying the relation 4.3 ≤ FOV / CRA ≤ 5.6;

[0157] The effective focal length f of the first lens group 1 u1 and the effective focal length f of the second lens group 3 u2 , and the maximum image height IH, the relationship among them is: (f u1 +f u2 ) / IH = 13.4891, satisfying the relation 13 ≤ (f u1 +f u2 ) / IH ≤ 26;

[0158] The relationship among the maximum field of view FOV, the head aperture size D, and the total optical length TTL of the industrial lens is: TTLFOV / (D*TTL) = 0.0278, satisfying the relation FOV / (D*TTL) ≥ 0.025;

[0159] The optical power f of the first lens group 1 u1, Relationship with the effective focal length f of the entire industrial lens: |f u1 / f| = 3.6332, satisfying the relationship |f u1 / f| ≤ 8.1;

[0160] The optical power f u2 , Relationship with the effective focal length f of the entire industrial lens: |f u2 / f| = 1.0094, satisfying the relationship |f u2 / f| ≥ 0.86;

[0161] Relationship between the Abbe number VD5 of the fifth lens 8 and the Abbe number VD6 of the sixth lens 9: |VD5 - VD6| = 42.6579, satisfying the relationship 35 ≤ |VD5 - VD6| ≤ 43;

[0162] The refractive index Nd5 of the fifth lens 8 is 1.4875, satisfying Nd5 ≤ 1.7;

[0163] The Abbe number VD5 of the fifth lens 8 is 70.4196, satisfying VD5 ≥ 63;

[0164] The refractive index Nd4 of the fourth lens 7 is 1.8348, Nd4 ≥ 1.8.

[0165] The modulation transfer function diagram of this Embodiment 2 is as shown in Figure 8 . Taking the distance from the image field center to the image field edge as the abscissa, it reflects the imaging quality at the lens edge. It can be seen that the imaging quality of this industrial lens is very uniform from the center to the edge of the field of view, that is, the entire image is very clear, and the imaging clarity is guaranteed.

[0166] The MTF curve generated by the line parallel to the diameter is called the sagittal curve, labeled as the S curve, and the MTF curve generated by the line parallel to the tangent is called the meridional curve, labeled as the T curve. Figure 8 There are multiple groups of MTF variation curves from the image field center to the image field edge, reflecting that this industrial lens has high resolution.

[0167] The field curvature / F - Tan(θ) distortion schematic diagram of this Embodiment 2 is as shown in Figure 9 . The left part is the schematic diagram of field curvature, where the abscissa represents the field curvature size, the unit is mm, and the ordinate represents the image height. In the figure, both the meridional field curvature value and the sagittal field curvature value are controlled within ±0.1 mm, indicating that the field curvature of the industrial lens has been well corrected; the right part is the schematic diagram of distortion, where the abscissa represents the distortion size, the unit is percentage, and the ordinate represents the image height. As can be seen from Figure 9 , the F - Tan(θ) distortion value is controlled within -1.2%, indicating that the distortion of the industrial lens has been well corrected.

[0168] The schematic diagram of the lateral chromatic aberration of Embodiment 2 is as Figure 10 shown, Figure 10 in which the abscissa represents the magnitude of the lateral chromatic aberration, with the unit of μm, the ordinate represents the image height, which represents the chromatic aberration of each wavelength at different image heights on the imaging plane, the horizontal axis represents the offset, with the unit of μm, and the vertical axis represents the object height, with the unit of mm. From Figure 10 it can be seen that the lateral chromatic aberration between the shortest wavelength and the longest wavelength is controlled within ±2 μm, indicating that the industrial lens can correct the chromatic aberration of the edge field of view well.

[0169] The axial aberration curve diagram of Embodiment 2 is as Figure 11 shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the offset, with the unit of mm, and the vertical axis represents the normalized pupil radius. From Figure 11 it can be seen that the axial aberration between the shortest wavelength and the longest wavelength is controlled within ±0.05 mm, indicating that the axial aberration of the industrial lens has been well corrected.

[0170] From Figures 8 - 11 it can be seen that this industrial lens has low distortion, low chromatic aberration, and high resolution, and can achieve a better imaging effect.

[0171] Embodiment 3:

[0172] This embodiment provides an industrial lens, as Figure 12 shown. In Embodiment 3, the first lens 4 is a biconvex positive lens, the second lens 5 is a meniscus positive lens convex towards the object side, the third lens 6 is a biconcave negative lens, the fourth lens 7 is a biconvex positive lens, the fifth lens 8 is a biconvex positive lens, the sixth lens 9 is a biconcave negative lens, the seventh lens 10 is a meniscus positive lens convex towards the image side, and the eighth lens 11 is a biconvex positive lens.

[0173] Based on the structure of the industrial lens provided in the above Embodiment 3, in the industrial lens including a biconvex positive lens, a meniscus positive lens convex towards the object side, a biconcave negative lens, a biconvex positive lens, a diaphragm 2, a biconvex positive lens, a biconcave negative lens, a meniscus positive lens convex towards the image side, a biconvex positive lens, and an imaging plane 12 arranged coaxially in sequence, Table 5 shows the parameters of each lens of the industrial lens.

[0174] Table 5:

[0175]

[0176]

[0177] Combined with Figure 1 and Figure 12As shown, the object side S1 of the first lens 4, which is a biconvex positive lens, is convex, and the image side S2 is convex; the object side S3 of the second lens 5, which is a meniscus positive lens, is convex, and the image side S4 is concave;

[0178] the object side S5 of the third lens 6, which is a biconcave negative lens, is concave, and the image side S6 is concave;

[0179] the object side S7 of the fourth lens 7, which is a biconvex positive lens, is convex, and the image side S8 is convex;

[0180] the object side S10 of the fifth lens 8, which is a biconvex positive lens, is convex, and the image side S11 is convex;

[0181] the object side S11 of the sixth lens 9, which is a biconcave negative lens, is concave, and the image side S12 is concave;

[0182] The fifth lens 8 and the sixth lens 9 are cemented lenses and share S11. Therefore, S11 is convex with respect to the fifth lens 8 and concave with respect to the sixth lens 9;

[0183] the object side S13 of the seventh lens 10, which is a meniscus positive lens, is concave, and the image side S14 is convex;

[0184] the object side S15 of the eighth lens 11, which is a biconvex positive lens, is convex, and the image side S16 is convex;

[0185] IMA is the imaging surface.

[0186] In the present Embodiment 3, the parameters of the industrial lens are shown in Table 6.

[0187] Table 6:

[0188] FOV 38.0000 CRA 6.9048 <![CDATA[f u1 > 131.1678 <![CDATA[f u2 > 14.1606 f 16.3764 D 24.9130 TTL 55.9775 IH 5.5970 <![CDATA[Nd4]]> 1.8348 <![CDATA[Nd5]]> 1.6180 <![CDATA[VD5]]> 63.4058 <![CDATA[VD6]]> 27.7617

[0189] As can be seen from Table 6 above, in the present Embodiment 3, the relationship between the maximum field of view FOV of the industrial lens and the chief ray angle of incidence CRA of the industrial lens is: FOV / CRA = 5.5034, satisfying the relationship 4.3 ≤ FOV / CRA ≤ 5.6;

[0190] The effective focal length f of the first lens group 1 u1 , the effective focal length f of the second lens group 3 u2 , and the maximum image height IH satisfy the relationship: (f u1 + f u2 ) / IH = 25.9654, satisfying the relationship 13 ≤ (f u1 + f u2 ) / IH ≤ 26;

[0191] The relationship among the maximum field of view FOV, the head aperture size D, and the total optical length TTL of the industrial lens: TTLFOV / (D * TTL) = 0.0272, satisfying the relation FOV / (D * TTL) ≥ 0.025;

[0192] The optical power f of the first lens group 1 u1 、and the relationship with the effective focal length f of the entire industrial lens: |f u1 / f| = 8.0096, satisfying the relation |f u1 / f| ≤ 8.1;

[0193] The optical power f of the second lens group 3 u2 、and the relationship with the effective focal length f of the entire industrial lens: |f u2 / f| = 0.8647, satisfying the relation |f u2 / f| ≥ 0.86;

[0194] The relationship between the Abbe number VD5 of the fifth lens 8 and the Abbe number VD6 of the sixth lens 9: |VD5 - VD6| = 35.6441, satisfying the relation 35 ≤ |VD5 - VD6| ≤ 43;

[0195] The refractive index Nd5 of the fifth lens 8 is 1.6180, satisfying Nd5 ≤ 1.7;

[0196] The Abbe number VD5 of the fifth lens 8 is 63.4058, satisfying VD5 ≥ 63;

[0197] The refractive index Nd4 of the fourth lens 7 is 1.8348, Nd4 ≥ 1.8.

[0198] The modulation transfer function graph of this Embodiment 3 is as Figure 13 shown. Taking the distance from the image field center to the image field edge as the abscissa, it reflects the imaging quality at the lens edge. It can be seen that the imaging quality of this industrial lens is very uniform from the center to the edge of the field of view, that is, the entire image is very clear, and the imaging clarity is guaranteed.

[0199] The MTF curve generated by the line parallel to the diameter is called the sagittal curve, labeled as the S curve, and the MTF curve generated by the line parallel to the tangent is called the meridional curve, labeled as the T curve. Figure 13 There are multiple groups of MTF change curves from the image field center to the image field edge, reflecting that this industrial lens has a high resolution.

[0200] The field curvature / F - Tan(θ) distortion schematic diagram of this Embodiment 3 is as Figure 14As shown in the figure, the left part is a schematic diagram of field curvature, where the abscissa represents the magnitude of field curvature in mm, and the ordinate represents the image height. In the figure, both the meridional field curvature value and the sagittal field curvature value are controlled within ±0.1 mm, indicating that the field curvature of the industrial lens has been well corrected; the right part is a schematic diagram of distortion, where the abscissa represents the magnitude of distortion in percentage, and the ordinate represents the image height. As can be seen from Figure 14 it, the F-Tan(θ) distortion value is controlled within -1%, indicating that the distortion of the industrial lens has been well corrected.

[0201] The schematic diagram of lateral chromatic aberration of Embodiment 3 is as shown in Figure 15 . Figure 15 In it, the abscissa represents the magnitude of lateral chromatic aberration in μm, and the ordinate represents the image height, which represents the chromatic aberration of each wavelength at different image heights on the imaging plane. The horizontal axis represents the offset in μm, and the vertical axis represents the object height in mm. As can be seen from Figure 15 it, the lateral chromatic aberration between the shortest wavelength and the longest wavelength is controlled within ±1.5 μm, indicating that the industrial lens can better correct the chromatic aberration of the edge field of view.

[0202] The axial aberration curve diagram of Embodiment 3 is as shown in Figure 16 . It represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the offset in mm, and the vertical axis represents the normalized pupil radius. As can be seen from Figure 16 it, the axial aberration between the shortest wavelength and the longest wavelength is controlled within ±0.07 mm, indicating that the axial aberration of the industrial lens has been well corrected.

[0203] It can be seen from Figures 13 - 16 that this industrial lens has low distortion, low chromatic aberration, and high resolution, and can achieve better imaging effects.

[0204] This application also proposes an optical device. The optical device includes the industrial lens in any of the foregoing embodiments, and the specific structure of the industrial lens refers to any of the foregoing embodiments. Since the optical device proposed in this application can apply all the technical solutions in all the foregoing embodiments, it has at least all the beneficial effects brought by the foregoing technical solutions, which will not be elaborated here one by one.

[0205] The above are only optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. An industrial lens, characterized in that: It includes a first lens group (1), a diaphragm (2), and a second lens group (3) which are coaxially arranged in sequence. The first lens group (1) includes a first lens (4), a second lens (5), a third lens (6), and a fourth lens (7) which are arranged in sequence along the optical axis from the object side to the image side. The first lens (4), the second lens (5), and the fourth lens (7) have positive optical powers, and the third lens (6) has a negative optical power; The second lens group (3) includes a fifth lens (8), a sixth lens (9), a seventh lens (10), and an eighth lens (11) which are arranged in sequence along the optical axis from the object side to the image side. The fifth lens (8), the seventh lens (10), and the eighth lens (11) have positive optical powers, and the sixth lens (9) has a negative optical power; The industrial lens satisfies the following relational expressions, 3 ≤ FOV / CRA ≤ 5.6; 13 ≤ (f u1 + f u2 ) / IH ≤ 26; FOV / (D * TTL) ≥ 0.025; Wherein, FOV is the maximum field of view angle of the industrial lens, CRA is the chief ray angle of incidence of the industrial lens, 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 (3) in the industrial lens, IH is the maximum image plane height of the industrial lens, D is the head aperture size of the industrial lens, and TTL is the total optical length of the industrial lens.

2. The industrial lens according to claim 1, characterized in that: The first lens (4) and the second lens (5) are meniscus positive lenses convex towards the object side, the third lens (6) is a biconcave negative lens, the fourth lens (7) is a biconvex positive lens, the fifth lens (8) is a plano-convex positive lens, the sixth lens (9) is a biconcave negative lens, the seventh lens (10) is a meniscus positive lens convex towards the image side, and the eighth lens (11) is a biconvex positive lens.

3. An industrial lens according to claim 1, characterized in that: The first lens (4) is a biconvex positive lens, the second lens (5) is a meniscus positive lens convex towards the object side, the third lens (6) is a biconcave negative lens, the fourth lens (7) is a biconvex positive lens, the fifth lens (8) is a meniscus positive lens convex towards the image side, the sixth lens (9) is a biconcave negative lens, the seventh lens (10) is a meniscus positive lens convex towards the image side, and the eighth lens (11) is a biconvex positive lens.

4. An industrial lens according to claim 1, characterized in that: The first lens (4) is a biconvex positive lens, the second lens (5) is a meniscus positive lens convex towards the object side, the third lens (6) is a biconcave negative lens, the fourth lens (7) is a biconvex positive lens, the fifth lens (8) is a biconvex positive lens, the sixth lens (9) is a biconcave negative lens, the seventh lens (10) is a meniscus positive lens convex towards the image side, and the eighth lens (11) is a biconvex positive lens.

5. An industrial lens according to claim 1, wherein: The industrial lens also satisfies the following relational expressions, |f u1 / f| ≤ 8.1; |f u2 / f| ≥ 0.86; where f is the effective focal length of the industrial lens.

6. An industrial lens according to any one of claims 1, characterized in that: The fifth lens (8) and the sixth lens (9) are doublet lenses and are glass lenses.

7. The industrial lens according to claim 6, wherein: The industrial lens also satisfies the following relational expressions, 35 ≤ |VD5 - VD6| ≤ 43, where VD5 is the Abbe number of the fifth lens (8), and VD6 is the Abbe number of the sixth lens (9).

8. An industrial lens according to claim 1, characterized in that: The industrial lens also satisfies the following relational expressions, Nd4 ≥ 1.8, where Nd4 is the refractive index of the lens material of the fourth lens (7) in the industrial lens at the Fraunhofer spectral lines.

9. An industrial lens according to claim 6, characterized in that: The industrial lens also satisfies the following relational expressions, Nd5 ≤ 1.7; VD5 ≥ 63; where Nd5 is the refractive index of the lens material of the fifth lens (8) in the industrial lens at the Fraunhofer spectral line, and VD5 is the Abbe number of the fifth lens (8).

10. An optical device, characterized in that: An industrial lens comprising any one of the industrial lenses according to claims 1-9.

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