An industrial lens

Abstract

This invention discloses an industrial lens, comprising a first lens group, a second lens group, and a third lens group. The positions of the first and third lens groups are fixed, while the position of the second lens group is movable. The first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The second lens group includes a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens. The third lens group includes a thirteenth lens and a fourteenth lens. The movement of the second lens group along the optical axis enables focusing at different object distances. The fixed position of the first and third lens groups reduces the impact of focusing at different object distances on resolution, ensuring balanced image quality at various working distances. Furthermore, the rational setting of the number of lenses in each lens group is beneficial for achieving a high-quality industrial lens.

Description

Technical Field

[0001] This invention relates to the field of optical device technology, and more particularly to an industrial lens. Background Technology

[0002] With the increasing demand for automated equipment, the application of optical lenses is becoming more and more sophisticated, especially in the field of precision inspection, such as dimensional measurement, PCB board defect detection, and wafer defect detection. However, high-resolution optical lenses are currently very scarce in the market. As modern automated equipment gradually increases its requirements for inspection accuracy, the performance requirements for optical lenses in terms of field of view, resolution, and optical distortion are becoming increasingly stringent. Summary of the Invention

[0003] This invention provides an industrial lens that achieves high image quality imaging performance.

[0004] This invention provides an industrial lens, comprising a first lens group, a second lens group, and a third lens group arranged sequentially along the optical axis from the object plane to the image plane; the positions of the first lens group and the third lens group are fixed, while the position of the second lens group can float along the optical axis;

[0005] The first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the second lens group includes a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens; and the third lens group includes a thirteenth lens and a fourteenth lens.

[0006] Optionally, the optical power of the first lens group is The optical power of the second lens group is The optical zoom of the industrial lens is:

[0007] in,

[0008] Optionally, the first lens and the second lens are cemented together, the third lens and the fourth lens are cemented together, and the fifth lens and the sixth lens are cemented together.

[0009] The eighth lens and the ninth lens are cemented together, and the tenth lens, the eleventh lens and the twelfth lens are cemented together.

[0010] Optionally, the optical power of the first lens is The Abbe number is vd11; the optical power of the second lens is... The Abbe number is vd12; the optical power of the third lens is... The Abbe number is vd13; the optical power of the fourth lens is... The Abbe number is vd14; the optical power of the fifth lens is... The Abbe number is vd15; the optical power of the sixth lens is... The Abbe number is vd16;

[0011] in,

[0012]

[0013] Optionally, the tenth lens is a positive power lens and its optical power is [missing value]. The eleventh lens is a negative power lens and its power is [missing value]. The twelfth lens is a positive power lens and its optical power is [missing value]. The optical zoom of the industrial lens is:

[0014] The tenth lens has a refractive index of nd24 and an Abbe number of vd24; the eleventh lens has a refractive index of nd25 and an Abbe number of vd25; and the twelfth lens has a refractive index of nd26 and an Abbe number of vd26.

[0015] in,

[0016] nd24<nd25, nd26<nd25, vd24<vd25, vd26<vd25.

[0017] Optionally, the optical power of the seventh lens is... The optical power of the eighth lens is: The optical zoom of the industrial lens is:

[0018] in,

[0019] Optionally, the moving distance of the second lens group is ZOL, and the distance between the image-side surface of the fourteenth lens and the image plane is BFL;

[0020] Among them, 0.3390≤ZOL / BFL≤0.8787.

[0021] Optionally, the first lens includes a first object-side surface near the object surface and a first image-side surface near the image surface, wherein the first object-side surface is convex and the first image-side surface is concave or convex.

[0022] The second lens includes a second object-side surface near the object surface and a second image-side surface near the image surface. The second object-side surface is either convex or concave, and the second image-side surface is concave.

[0023] The third lens includes a third object-side surface near the object plane and a third image-side surface near the image plane. The third object-side surface is either convex or concave, and the third image-side surface is either convex or concave.

[0024] The fourth lens includes a fourth object-side surface near the object plane and a fourth image-side surface near the image plane. The fourth object-side surface is concave or convex, and the fourth image-side surface is concave, planar, or convex.

[0025] The fifth lens includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane. The fifth object-side surface is either convex or concave, and the fifth image-side surface is concave.

[0026] The sixth lens includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane. The sixth object-side surface is convex, and the sixth image-side surface is convex.

[0027] The seventh lens includes a seventh object-side surface near the object plane and a seventh image-side surface near the image plane. The seventh object-side surface is convex, and the seventh image-side surface is concave or convex.

[0028] The eighth lens includes an eighth object-side surface near the object plane and an eighth image-side surface near the image plane. The eighth object-side surface is convex, and the eighth image-side surface is either convex or concave.

[0029] The ninth lens includes a ninth object-side surface near the object plane and a ninth image-side surface near the image plane. The ninth object-side surface is either concave or convex, and the ninth image-side surface is concave.

[0030] The tenth lens includes a tenth object-side surface near the object plane and a tenth image-side surface near the image plane. The tenth object-side surface is convex, and the tenth image-side surface is convex.

[0031] The eleventh lens includes an eleventh object-side surface near the object plane and an eleventh image-side surface near the image plane. The eleventh object-side surface is concave, and the eleventh image-side surface is concave.

[0032] The twelfth lens includes a twelfth object-side surface near the object plane and a twelfth image-side surface near the image plane. The twelfth object-side surface is convex, and the twelfth image-side surface is convex.

[0033] The thirteenth lens includes a thirteenth object-side surface near the object plane and a thirteenth image-side surface near the image plane. The thirteenth object-side surface is concave, and the thirteenth image-side surface is concave.

[0034] The fourteenth lens includes a fourteenth object-side surface near the object plane and a fourteenth image-side surface near the image plane. The fourteenth object-side surface is convex, and the fourteenth image-side surface is either convex or concave.

[0035] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the fourteenth lens are all glass spherical lenses;

[0036] The thirteenth lens is a glass aspherical lens.

[0037] Optionally, the industrial lens further includes an aperture stop disposed in the optical path between the ninth lens and the tenth lens.

[0038] The industrial lens provided in this embodiment of the invention features a second lens group that can float along the optical axis, ensuring focusing at different working distances and achieving clear imaging at different object distances. Furthermore, the first and third lens groups remain fixed, thus reducing the impact of focusing at different object distances on resolution and ensuring balanced image quality at each working distance, resulting in a high-quality industrial lens.

[0039] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of an industrial lens at the optimal object distance provided in Embodiment 1 of the present invention;

[0042] Figure 2 This is a schematic diagram of the MTF curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of the present invention.

[0043] Figure 3 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of the present invention.

[0044] Figure 4This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 2 of the present invention;

[0045] Figure 5 This is a schematic diagram of the MTF curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of the present invention.

[0046] Figure 6 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of the present invention.

[0047] Figure 7 This is a schematic diagram of the structure of an industrial lens at the optimal object distance provided in Embodiment 3 of the present invention;

[0048] Figure 8 This is a schematic diagram of the MTF curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of the present invention;

[0049] Figure 9 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] Example 1

[0052] Figure 1 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 1 of the present invention, as shown below. Figure 1 As shown, the industrial lens provided in this embodiment of the invention includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged sequentially along the optical axis from the object plane to the image plane; the positions of the first lens group S1 and the third lens group S3 are fixed, while the position of the second lens group S2 can float along the optical axis; the first lens group S1 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, and a sixth lens 106; the second lens group S2 includes a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, an eleventh lens 111, and a twelfth lens 112; the third lens group S3 includes a thirteenth lens 113 and a fourteenth lens 114.

[0053] Specifically, the industrial lens provided in this embodiment of the invention includes a first lens group S1, a third lens group S3, and a second lens group S2 located between the first lens group S1 and the third lens group S3 along the optical axis. The first lens group S1 and the third lens group S3 can both be understood as lenses with fixed positions, while the second lens group S2 can be understood as a lens group whose position changes. Specifically, the second lens group S2 moves between the first lens group S1 and the third lens group S3. The focal length of the industrial lens is adjusted by changing the position of the second lens group S2 to ensure that the industrial lens can focus at different object distances and to ensure clear imaging at different object distances. Specifically, when focusing at close object distances, the second lens group S2 is closer to the first lens group S1; when focusing at infinity, the second lens group S2 is closer to the third lens group S3. Furthermore, since the positions of the first lens group S1 and the third lens group S3 remain fixed, the aberration changes caused by the movement of the second lens group S2 at different working distances will be reduced due to the fixed positions of the first lens group S1 and the third lens group S3 maintaining symmetry. This ensures that the image quality at each working distance is balanced and guarantees the imaging quality.

[0054] Furthermore, the first lens group S1 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, and a sixth lens 106; the second lens group S2 includes a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, an eleventh lens 111, and a twelfth lens 112; and the third lens group S3 includes a thirteenth lens 113 and a fourteenth lens 114. In other words, the first lens group S1 includes six lenses, the second lens group S2 includes six lenses, and the third lens group S3 includes two lenses. This means the industrial lens includes eight fixed lenses and six movable focusing lenses. This allows for focusing through the movement of multiple lenses, ensuring good focusing performance; simultaneously, the fixed lenses reduce the impact of the second lens group S2's movement on aberrations, ensuring balanced image quality at various working distances and guaranteeing overall image quality.

[0055] In summary, the industrial lens provided by this invention features a second lens group that can float along the optical axis, ensuring focusing at different working distances and achieving clear imaging at different object distances. The movement of multiple lenses during focusing ensures good focusing performance. Furthermore, the first and third lens groups remain fixed, reducing the impact of different object distances on resolution and ensuring balanced image quality at various working distances, resulting in a high-quality industrial lens. Moreover, the arrangement of fourteen lenses ensures a reasonable number of lenses in the optical system, preventing excessive lens size or excessive aberrations caused by a single lens bearing too much optical power due to insufficient lens quantity. This approach ensures both miniaturization of the optical system and low imaging aberrations, resulting in high image quality.

[0056] Based on the above embodiments, continue to refer to Figure 1 As shown, the industrial lens provided in this embodiment of the invention also includes an aperture stop STO, which is disposed in the optical path between the ninth lens 109 and the tenth lens 110.

[0057] Specifically, setting the aperture stop STO can adjust the propagation direction of the light beam, which helps improve image quality. Furthermore, in this industrial lens, the aperture stop STO is positioned in the optical path between the ninth lens 109 and the tenth lens 110, meaning the aperture stop STO is integrated into the optical system. This allows for a smaller aperture value, enabling a larger aperture. Moreover, the aperture stop STO is positioned between the two lenses in the second lens group S2, and it moves along with the second lens group S2 during focusing, ensuring image quality during the focusing process.

[0058] Furthermore, the industrial lens provided in this embodiment of the invention may also include a filter 115, which is disposed in the optical path between the fourteenth lens 114 and the image plane, and can filter out stray light and improve the imaging effect.

[0059] Furthermore, the industrial lens provided in this embodiment of the invention may also include a protective glass and an image acquisition element. The protective glass may be disposed on the image-side of the filter, and the image acquisition element may be disposed on the image-side of the protective glass. The optical system is protected by the protective glass, and images are acquired by the image acquisition element, thus enabling the optical system to perform its normal imaging function.

[0060] Based on the above embodiments, the optical power of the first lens group S1 is The optical power of the second lens group S2 is: The optical focal length of industrial lenses is in,

[0061] Specifically, optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam; it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger its ability to bend light; the smaller the absolute value, the weaker its ability to bend light. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging.

[0062] Because an excessively large off-axis deflection angle of the front-end lens group significantly impacts aberrations. The above solution constrains the optical power of the front-end lens group in industrial lenses. Setting the optical power of the first lens group S1 and the second lens group S2 within this range allows for a smoother transition of light within the lens, reducing the impact on imaging aberrations.

[0063] Based on the above embodiments, the first lens 101 and the second lens 102 are cemented together, the third lens 103 and the fourth lens 104 are cemented together, the fifth lens 105 and the sixth lens 106 are cemented together; the eighth lens 108 and the ninth lens 109 are cemented together, and the tenth lens 110, the eleventh lens 111 and the twelfth lens 112 are cemented together.

[0064] Specifically, different lens cementation settings can be understood as the image-side surface of the preceding lens and the object-side surface of the following lens being bonded together in the optical path, possessing the same surface shape. For example... Figure 1 As shown, the first lens 101 and the second lens 102 are cemented together, which can be understood as the image-side of the first lens 101 being bonded to the object-side of the second lens 102. The third lens 103 and the fourth lens 104 are cemented together, which can be understood as the image-side of the third lens 103 being bonded to the object-side of the fourth lens 104. The fifth lens 105 and the sixth lens 106 are cemented together, which can be understood as the image-side of the fifth lens 105 being bonded to the object-side of the sixth lens 106. That is, the first lens group S1 may include three groups of lenses cemented together in pairs.

[0065] The eighth lens 108 and the ninth lens 109 are cemented together, which can be understood as the image-side surface of the eighth lens 108 being bonded to the object-side surface of the ninth lens 109. Similarly, the tenth lens 110, the eleventh lens 111, and the twelfth lens 112 are cemented together, which can be understood as the image-side surface of the tenth lens 110 being bonded to the object-side surface of the eleventh lens 111, and the image-side surface of the eleventh lens 111 being bonded to the object-side surface of the twelfth lens 112. In other words, the second lens group S2 can include a group of lenses cemented together in pairs and a group of lenses cemented together in triplicates.

[0066] Cemented lenses can be used to minimize or eliminate chromatic aberration. In industrial lenses, the use of cemented lenses improves image quality and reduces light energy reflection loss, thereby enhancing image sharpness. Furthermore, the cementation process eliminates the air gap between the two lenses, resulting in a more compact optical system that meets miniaturization requirements. Additionally, cementation reduces tolerance sensitivity issues such as tilting / eccentricity that occur during lens assembly.

[0067] Furthermore, the first lens 101 and the second lens 102 can be bonded together by using a gasket or by using glue; the third lens 103 and the fourth lens 104 can be bonded together by using a gasket or by using glue; the fifth lens 105 and the sixth lens 106 can be bonded together by using a gasket or by using glue; the eighth lens 108 and the ninth lens 109 can be bonded together by using a gasket or by using glue; the tenth lens 110, the eleventh lens 111 and the twelfth lens 112 can be bonded together by using a gasket or by using glue.

[0068] Based on the above embodiments, the optical power of the first lens 101 is: The Abbe number is vd11; the optical power of the second lens 102 is... The Abbe number is vd12; the optical power of the third lens 103 is... The Abbe number is vd13; the optical power of the fourth lens 104 is... The Abbe number is vd14; the optical power of the fifth lens 105 is... The Abbe number is vd15; the optical power of the sixth lens is 106. The Abbe number is vd16; among which...

[0069]

[0070] This condition can constrain the optical power and chromatic aberration of the cemented doublet formed by the combination of the first lens 101 and the second lens 102, the cemented doublet formed by the combination of the third lens 103 and the fourth lens 104, and the cemented doublet formed by the combination of the fifth lens 105 and the sixth lens 106, thereby improving image quality.

[0071] Based on the above embodiments, the tenth lens is a positive power lens and its optical power is [missing information]. The eleventh lens is a negative power lens and its power is... The twelfth lens is a positive power lens and its power is [missing value]. The optical focal length of industrial lenses is The tenth lens 110 has a refractive index of nd24 and an Abbe number of vd24; the eleventh lens 111 has a refractive index of nd25 and an Abbe number of vd25; and the twelfth lens 112 has a refractive index of nd26 and an Abbe number of vd26.

[0072]

[0073] Specifically, the tenth lens 110, the eleventh lens 111, and the twelfth lens 112 form a cemented three-lens system. The structure of these lenses is a combination of positive and negative positive lenses. The negative-power lens in the cemented three-lens system possesses high refractive index and high dispersion, while the positive-power lens possesses low refractive index and low dispersion, i.e., nd24 < nd25, nd26 < nd25, vd24 < vd25, vd26 < vd25. By further limiting the optical power of the tenth lens 110, the eleventh lens 111, and the twelfth lens 112, the cemented three-lens system ensures good correction capabilities for astigmatism and coma, thereby improving image quality.

[0074] Based on the above embodiments, the optical power of the seventh lens 107 is The optical power of the eighth lens 108 is The optical focal length of industrial lenses is in, By limiting the optical power of the seventh lens 107 and the eighth lens 108 to this range, lens distortion can be balanced and image quality can be guaranteed. In this embodiment of the invention, the optical distortion is ≤0.1%.

[0075] Based on the above embodiment, the moving distance of the second lens group S2 is ZOL, and the distance between the image side and the image plane of the fourteenth lens 114 is BFL; wherein, 0.3390≤ZOL / BFL≤0.8787.

[0076] Specifically, the distance between the image-side surface and the image plane of the fourteenth lens 114 can be understood as the distance from the vertex of the last optical surface of the optical system to the image plane, or as the back focal length of the optical system. By limiting 0.3390≤ZOL / BFL≤0.8787, it is beneficial to compress the total length of industrial lenses.

[0077] Based on the above embodiments, the first lens 101 includes a first object-side surface near the object plane and a first image-side surface near the image plane, wherein the first object-side surface is convex and the first image-side surface is concave or convex; the second lens 102 includes a second object-side surface near the object plane and a second image-side surface near the image plane, wherein the second object-side surface is convex or concave and the second image-side surface is concave; the third lens 103 includes a third object-side surface near the object plane and a third image-side surface near the image plane, wherein the third object-side surface is convex or concave and the third image-side surface is convex or concave; the fourth lens 104 includes a fourth object-side surface near the object plane. The fourth object-side surface and the fourth image-side surface near the image plane are both concave or convex, and the fourth image-side surface is concave, planar, or convex. The fifth lens 105 includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane; the fifth object-side surface is convex or concave, and the fifth image-side surface is concave. The sixth lens 106 includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane; the sixth object-side surface is convex, and the sixth image-side surface is convex. The seventh lens 107 includes a seventh object-side surface near the object plane and a seventh image-side surface near the image plane; the seventh object-side surface is convex, and the seventh image-side surface is... The eighth lens 108 includes an eighth object-side surface near the object plane and an eighth image-side surface near the image plane. The eighth object-side surface is convex, and the eighth image-side surface is either convex or concave. The ninth lens 109 includes a ninth object-side surface near the object plane and a ninth image-side surface near the image plane. The ninth object-side surface is either concave or convex, and the ninth image-side surface is concave. The tenth lens 110 includes a tenth object-side surface near the object plane and a tenth image-side surface near the image plane. The tenth object-side surface is convex, and the tenth image-side surface is convex. The eleventh lens 111 includes an eleventh object-side surface near the object plane and an eleventh image-side surface near the image plane. The eleventh image side and the eleventh object side are concave. The eleventh image side is concave. The twelfth lens 112 includes the twelfth object side near the object plane and the twelfth image side near the image plane. The twelfth object side and the twelfth image side are convex. The thirteenth lens 113 includes the thirteenth object side near the object plane and the thirteenth image side near the image plane. The thirteenth object side and the thirteenth image side are concave. The fourteenth lens 114 includes the fourteenth object side near the object plane and the fourteenth image side near the image plane. The fourteenth object side is convex, and the fourteenth image side is either convex or concave.

[0078] Specifically, the object-side surface of a lens can be understood as the surface of the lens closest to the object plane, and the image-side surface of a lens can be understood as the surface of the lens closest to the image plane.

[0079] The object side of the first lens 101 is convex, and the image side is concave or convex. It can be understood that the object side of the first lens 101 convexes towards the object surface near the optical axis, and the image side is concave or convex towards the image surface near the optical axis. In other words, the first lens 101 is a lens with a convex-concave structure or a biconvex structure. Figure 1 The structure shown is illustrated using the first lens 101 as an example of a convex-concave structure lens.

[0080] The object side of the second lens 102 is either convex or concave, and the image side is concave. This can be understood as the object side of the second lens 102 being convex or concave towards the object surface near the optical axis, and the image side being concave towards the image surface near the optical axis. In other words, the second lens 102 is a lens with a convex-concave structure or a double-concave structure. Figure 1 The structure shown is illustrated using the second lens 102 as an example of a convex-concave structure lens.

[0081] The object side of the third lens 103 is either convex or concave, and the image side is either convex or concave. This can be understood as the object side of the third lens 103 being convex or concave towards the object surface near the optical axis, and the image side being convex or concave towards the image surface near the optical axis. In other words, the third lens 103 can be a lens with a biconvex structure, a convex-concave structure, or a biconcave structure. Figure 1 The structure shown is illustrated using the third lens 103 as an example of a biconvex lens.

[0082] The object side of the fourth lens 104 is concave or convex, and the image side is concave, planar, or convex. It can be understood that the object side of the fourth lens 104 is concave or convex towards the object surface at the position near the optical axis, and the image side is concave, planar, or convex towards the image surface at the position near the optical axis. In other words, the fourth lens 104 can be a lens with a double concave structure, a convex-planar structure, or a double convex structure. Figure 1 The structure shown is illustrated using the fourth lens 104 as an example of a biconcave lens.

[0083] The object side of the fifth lens 105 is either convex or concave, and the image side is concave. This can be understood as the object side of the fifth lens 105 being convex or concave towards the object surface near the optical axis, and the image side being concave towards the image surface near the optical axis. In other words, the fifth lens 105 can be a lens with a convex-concave structure or a double-concave structure. Figure 1 The structure shown is illustrated using the fifth lens 105 as an example of a biconcave lens.

[0084] The object-side surface of the sixth lens 106 is convex, and the image-side surface is also convex. This can be understood as the object-side surface of the sixth lens 106 convex towards the object surface near the optical axis, and the image-side surface convex towards the image surface near the optical axis. In other words, the sixth lens 106 can be a lens with a biconvex structure. Figure 1The structure shown is illustrated using the sixth lens 106 as an example of a biconvex lens.

[0085] The object side of the seventh lens 107 is convex, and the image side is concave or convex. It can be understood that the object side of the seventh lens 107 convexes towards the object surface near the optical axis, and the image side is concave or convex towards the image surface near the optical axis. In other words, the seventh lens 107 can be a lens with a convex-concave structure or a biconvex structure. Figure 1 The structure shown is illustrated using the seventh lens 107 as an example of a convex-concave structure lens.

[0086] The object side of the eighth lens 108 is convex, and the image side is either convex or concave. This can be understood as the object side of the eighth lens 108 convex towards the object surface near the optical axis, and the image side convex or concave towards the image surface near the optical axis. In other words, the eighth lens 108 can be a lens with a biconvex or convex-concave structure. Figure 1 The structure shown is illustrated using the eighth lens 108 as an example of a biconvex lens.

[0087] The object side of the ninth lens 109 is concave or convex, and the image side is concave. This can be understood as the object side of the ninth lens 109 being concave or convex toward the object surface near the optical axis, and the image side being concave toward the image surface near the optical axis. In other words, the ninth lens 109 can be a lens with a biconcave or convex-concave structure. Figure 1 The structure shown is illustrated using the ninth lens 109 as an example of a biconcave lens.

[0088] The object-side surface of the tenth lens 110 is convex, and the image-side surface is also convex. This can be understood as the object-side surface of the tenth lens 110 convex towards the object surface near the optical axis, and the image-side surface convex towards the image surface near the optical axis. In other words, the tenth lens 110 can be a lens with a biconvex structure.

[0089] The object-side surface of the eleventh lens 111 is concave, and the image-side surface is also concave. This can be understood as the object-side surface of the eleventh lens 111 being concave towards the object plane near the optical axis, and the image-side surface being concave towards the image plane near the optical axis. In other words, the eleventh lens 111 can be a lens with a double concave structure.

[0090] The object-side surface of the twelfth lens 112 is convex, and the image-side surface is also convex. This can be understood as the object-side surface of the twelfth lens 112 convex towards the object surface near the optical axis, and the image-side surface convex towards the image surface near the optical axis. In other words, the twelfth lens 112 can be a lens with a biconvex structure.

[0091] The object-side surface of the thirteenth lens 113 is concave, and the image-side surface is also concave. This can be understood as the object-side surface of the thirteenth lens 113 being concave towards the object plane near the optical axis, and the image-side surface being concave towards the image plane near the optical axis. In other words, the thirteenth lens 113 can be a lens with a double concave structure.

[0092] The object side of the fourteenth lens 114 is convex, and the image side is either convex or concave. This can be understood as the object side of the fourteenth lens 114 convex towards the object surface near the optical axis, and the image side convex or concave towards the image surface near the optical axis. In other words, the fourteenth lens 114 can be a lens with a biconvex structure or a convex-concave structure. Figure 1 The structure shown is illustrated using the fourteenth lens 114 as an example of a biconvex lens.

[0093] By properly setting the concave and convex surfaces of each lens, the light emission angle of each lens can be modulated. Furthermore, for cemented lenses, it is possible to cement at least two adjacent lenses together. On the other hand, it can also reduce the spacing between adjacent lenses, which is beneficial for achieving small-volume industrial lens designs.

[0094] Based on the above embodiments, the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the eighth lens 108, the ninth lens 109, the tenth lens 110, the eleventh lens 111, the twelfth lens 112, and the fourteenth lens 114 are all glass spherical lenses; the thirteenth lens 113 is a glass aspherical lens.

[0095] Specifically, by setting the thirteenth lens 113 as an aspherical lens, field aberrations can be optimized, field curvature and distortion can be corrected, and imaging effects can be improved. Furthermore, the first lens 101, second lens 102, third lens 103, fourth lens 104, fifth lens 105, sixth lens 106, seventh lens 107, eighth lens 108, ninth lens 109, tenth lens 110, eleventh lens 111, twelfth lens 112, and fourteenth lens 14 are all glass spherical lenses. Using an optical structure of 13 glass spherical lenses and 1 glass aspherical lens better corrects chromatic aberration and aberrations, improves image quality, and reduces processing costs, achieving a higher cost-performance ratio. The materials of the glass spherical lenses and glass aspherical lenses are various types of glass known to those skilled in the art; this embodiment of the invention does not elaborate on or limit their application.

[0096] As a feasible implementation method, the parameters of each lens in the industrial lens will be explained next.

[0097] Table 1. Optical design values ​​for an industrial lens in Example 1.

[0098]

[0099] Table 2 Design values ​​of optical physical parameters for industrial lenses

[0100]

[0101]

[0102] The surface numbers in Table 2 are assigned according to the surface sequence of each lens. "0" represents the object surface, "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. The radius of curvature represents the degree of curvature of the corresponding lens surface; a positive value indicates that the surface bends towards the image surface, and a negative value indicates that the surface bends towards the object surface. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current location is air, with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface. Half-aperture indicates half the aperture size of the current surface.

[0103] Table 3. Design values ​​for the aspherical coefficient of industrial lenses.

[0104]

[0105] Wherein, 1.255784E-03 represents 1.255784 * 10 -3 All other parameters can be represented in this way.

[0106] Furthermore, the aspherical conic coefficients can be defined using the following aspherical formula, but are not limited to the following representations:

[0107]

[0108] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the conic coefficient; and AG are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial.

[0109] Table 4. One design value for focusing interval.

[0110] Object distance Object distance 150mm Object distance 10000mm Focusing interval 1 1.684mm 5.177mm Focusing interval 2 4.019mm 0.526mm

[0111] Figure 2This is a schematic diagram of the MTF curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of the present invention. The MTF curve represents the resolving power of the optical system for an object at different frequencies in different fields of view, meridional, and sagittal directions. It reflects the degree of image quality after the object passes through the optical system. The ideal curve is the diffraction limit at the highest point, indicating the physical limit of the lens under this parameter. The vertical axis of the curve corresponds to the contrast ratio of the black and white line boundaries (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging; therefore, 0 ≤ M' / M ≤ 1. The horizontal axis corresponds to the number of black and white lines within 1 mm. S and T correspond to the sagittal and meridional directions of each field of view. Figure 2 It can be seen that the system approaches the diffraction limit well at each wavelength in each field of view, indicating that the aberrations at each wavelength are well corrected. At the same time, there is no significant dispersion in the sagittal and meridional axes of each field of view, indicating that the astigmatism of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0112] Figure 3 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 1 of the present invention. The horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height, which has no unit; where the solid line represents the meridion and the dashed line represents the sagitta; Figure 3 It can be seen that the lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 3 As can be seen, the distortion of the lens provided in this embodiment has been well corrected, and the imaging distortion is small.

[0113] In summary, the industrial lens provided in this embodiment of the invention adopts an all-glass 14G structure. By matching lens materials and rationally allocating the optical power of each element, and using a central group focusing method, it achieves an industrial lens design that can balance high resolution and low optical distortion, with |optical distortion| ≤ 0.1% and full field of view MTF 230lp / mm > 0.3.

[0114] Example 2

[0115] Figure 4 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 2 of the present invention, as shown below. Figure 4As shown, the industrial lens provided in Embodiment 2 of the present invention includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged sequentially from the object plane to the image plane along the optical axis; the positions of the first lens group S1 and the third lens group S3 are fixed, while the position of the second lens group S2 can float along the optical axis; the first lens group S1 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, and a sixth lens 106; the second lens group S2 includes a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, an eleventh lens 111, and a twelfth lens 112; the third lens group S3 includes a thirteenth lens 113 and a fourteenth lens 114.

[0116] The difference between Embodiment 2 and Embodiment 1 is that the image-side surface of the first lens is convex; the object-side surface of the second lens is concave; the image-side surface of the third lens is concave; the object-side surface of the fourth lens is convex and the image-side surface is flat; the image-side surface of the seventh lens is convex; the object-side surface of the eighth lens is concave; and the image-side surface of the ninth lens is convex.

[0117] Other parameters are the same as in Example 1, and will not be repeated here.

[0118] As another feasible implementation method, the specific parameters in industrial lenses are explained below.

[0119] Table 5. Optical design values ​​for an industrial lens in Example 2.

[0120]

[0121] Table 6 Design values ​​of optical physical parameters for industrial lenses

[0122]

[0123]

[0124] The surface numbers in Table 6 are assigned according to the surface sequence of each lens. "0" represents the object surface, "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. The radius of curvature represents the degree of curvature of the corresponding lens surface; a positive value indicates that the surface bends towards the image surface, and a negative value indicates that the surface bends towards the object surface. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current location is air, with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface. Half-aperture indicates half the aperture size of the current surface.

[0125] Table 7. Design values ​​for the aspherical coefficient of industrial lenses.

[0126]

[0127] Wherein, 1.290913E-03 represents 1.290913 * 10 -3 All other parameters can be represented in this way.

[0128] Furthermore, the aspherical conic coefficients can be defined using the following aspherical formula, but are not limited to the following representations:

[0129]

[0130] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the conic coefficient; and AG are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial.

[0131] Table 8. One design value for focus interval.

[0132] Object distance Object distance 150mm Object distance 10000mm Focusing interval 1 0.136mm 7.072mm Focusing interval 2 7.933mm 0.997mm

[0133] Figure 5 This is a schematic diagram of the MTF curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of the present invention. The MTF curve represents the resolving power of the optical system for an object at different frequencies in different fields of view, meridional, and sagittal directions. It reflects the imaging quality of the object after passing through the optical system. The ideal curve is the diffraction limit at the highest point, indicating the physical limit of the lens under this parameter. The vertical axis of the curve corresponds to the contrast ratio of black and white line boundaries (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging; therefore, 0 ≤ M' / M ≤ 1. The horizontal axis corresponds to the number of black and white lines within 1 mm. S and T correspond to the sagittal and meridional directions of each field of view. Figure 5 It can be seen that the system approaches the diffraction limit well at each wavelength in each field of view, indicating that the aberrations at each wavelength are well corrected. At the same time, there is no significant dispersion in the sagittal and meridional axes of each field of view, indicating that the astigmatism of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0134] Figure 6 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 2 of the present invention. The horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height, which has no unit; where the solid line represents the meridion and the dashed line represents the sagitta; Figure 6It can be seen that the lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 6 As can be seen, the distortion of the lens provided in this embodiment has been well corrected, and the imaging distortion is small.

[0135] In summary, the industrial lens provided in this embodiment of the invention adopts an all-glass 14G structure. By matching lens materials and rationally allocating the optical power of each element, and using a central group focusing method, it achieves an industrial lens design that can balance high resolution and low optical distortion, with |optical distortion| ≤ 0.1% and full field of view MTF 230lp / mm > 0.3.

[0136] Example 3

[0137] Figure 7 This is a schematic diagram of the structure of an industrial lens at the optimal object distance according to Embodiment 3 of the present invention, as shown below. Figure 7 As shown, the industrial lens provided in Embodiment 3 of the present invention includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged sequentially from the object plane to the image plane along the optical axis; the positions of the first lens group S1 and the third lens group S3 are fixed, while the position of the second lens group S2 can float along the optical axis; the first lens group S1 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, and a sixth lens 106; the second lens group S2 includes a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, an eleventh lens 111, and a twelfth lens 112; the third lens group S3 includes a thirteenth lens 113 and a fourteenth lens 114.

[0138] The difference between Embodiment 3 and Embodiment 1 is that the object-side surface of the third lens is concave and the image-side surface is concave; the object-side surface of the fourth lens is convex and the image-side surface is convex; the object-side surface of the fifth lens is convex; the image-side surface of the eighth lens is concave; the object-side surface of the ninth lens is convex; and the image-side surface of the fourteenth lens is concave.

[0139] Other parameters are the same as in Example 1, and will not be repeated here.

[0140] As another feasible implementation method, the specific parameters in industrial lenses are explained below.

[0141] Table 9. Optical design values ​​for a fixed-focus lens in Example 3.

[0142]

[0143] Table 10 Optical Design Values ​​of Various Lenses in Industrial Lenses

[0144]

[0145]

[0146] The surface numbers in Table 10 are assigned according to the surface sequence of each lens. "0" represents the object surface, "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. The radius of curvature represents the degree of curvature of the corresponding lens surface; a positive value indicates that the surface bends towards the image surface, and a negative value indicates that the surface bends towards the object surface. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air, with a refractive index of 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface. Half-aperture indicates half the aperture size of the current surface.

[0147] Table 11 Design values ​​for the aspherical coefficient of industrial lenses

[0148]

[0149] Wherein, 1.192787E-03 represents 1.192787 * 10 -3 All other parameters can be represented in this way.

[0150] Furthermore, the aspherical conic coefficients can be defined using the following aspherical formula, but are not limited to the following representations:

[0151]

[0152] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the conic coefficient; and AG are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial.

[0153] Table 12. One design value for focusing interval.

[0154] Object distance Object distance 150mm Object distance 10000mm Focusing interval 1 3.24mm 6.9mm Focusing interval 2 4.343mm 0.68mm

[0155] Figure 8This is a schematic diagram of the MTF curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of the present invention. The MTF curve represents the resolving power of the optical system for an object at different frequencies in different fields of view, meridional, and sagittal directions. It reflects the imaging quality of the object after passing through the optical system. The ideal curve is the diffraction limit at the highest point, indicating the physical limit of the lens under this parameter. The vertical axis of the curve corresponds to the contrast ratio of black and white line boundaries (M' / M), where M refers to the grating modulation degree before imaging, and M' refers to the grating modulation degree after imaging; therefore, 0 ≤ M' / M ≤ 1. The horizontal axis corresponds to the number of black and white lines within 1 mm. S and T correspond to the sagittal and meridional directions of each field of view. Figure 8 It can be seen that the system approaches the diffraction limit well at each wavelength in each field of view, indicating that the aberrations at each wavelength are well corrected. At the same time, there is no significant dispersion in the sagittal and meridional axes of each field of view, indicating that the astigmatism of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0156] Figure 9 This is a schematic diagram of the field curvature distortion curve of an industrial lens at the optimal object distance, provided in Embodiment 3 of the present invention. The horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height, which has no unit; where the solid line represents the meridion and the dashed line represents the sagitta; Figure 9 It can be seen that the lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 9 As can be seen, the distortion of the lens provided in this embodiment has been well corrected, and the imaging distortion is small.

[0157] In summary, the industrial lens provided in this embodiment of the invention adopts an all-glass 14G structure. By matching lens materials and rationally allocating the optical power of each element, and using a central group focusing method, it achieves an industrial lens design that can balance high resolution and low optical distortion, with |optical distortion| ≤ 0.1% and full field of view MTF 230lp / mm > 0.3.

[0158] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An industrial lens, characterized in that, It includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object plane to the image plane along the optical axis; the positions of the first lens group and the third lens group are fixed, while the position of the second lens group can float along the optical axis. The first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the second lens group includes a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens; the third lens group includes a thirteenth lens and a fourteenth lens; the industrial lens has fourteen lenses with optical power; the first lens, the sixth lens, the seventh lens, the eighth lens, the tenth lens, the twelfth lens, and the fourteenth lens are all positive optical power lenses, and the second lens, the fifth lens, the ninth lens, the eleventh lens, and the thirteenth lens are all negative optical power lenses; The optical power of the first lens group is φ1, the optical power of the second lens group is φ2, and the optical power of the industrial lens is φ; wherein, -0.0919 < φ1 / φ < -0.0242, 1.0767 < φ2 / φ < 1.4985; The first lens includes a first object-side surface near the object surface and a first image-side surface near the image surface. The first object-side surface is convex, and the first image-side surface is concave or convex. The second lens includes a second object-side surface near the object surface and a second image-side surface near the image surface. The second object-side surface is either convex or concave, and the second image-side surface is concave. The third lens includes a third object-side surface near the object plane and a third image-side surface near the image plane. The third object-side surface is either convex or concave, and the third image-side surface is either convex or concave. The fourth lens includes a fourth object-side surface near the object plane and a fourth image-side surface near the image plane. The fourth object-side surface is concave or convex, and the fourth image-side surface is concave, planar, or convex. The fifth lens includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane. The fifth object-side surface is either convex or concave, and the fifth image-side surface is concave. The sixth lens includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane. The sixth object-side surface is convex, and the sixth image-side surface is convex. The seventh lens includes a seventh object-side surface near the object plane and a seventh image-side surface near the image plane. The seventh object-side surface is convex, and the seventh image-side surface is either concave or convex. The eighth lens includes an eighth object-side surface near the object plane and an eighth image-side surface near the image plane. The eighth object-side surface is convex, and the eighth image-side surface is either convex or concave. The ninth lens includes a ninth object-side surface near the object plane and a ninth image-side surface near the image plane. The ninth object-side surface is either concave or convex, and the ninth image-side surface is concave. The tenth lens includes a tenth object-side surface near the object plane and a tenth image-side surface near the image plane. The tenth object-side surface is convex, and the tenth image-side surface is convex. The eleventh lens includes an eleventh object-side surface near the object plane and an eleventh image-side surface near the image plane. The eleventh object-side surface is concave, and the eleventh image-side surface is concave. The twelfth lens includes a twelfth object-side surface near the object plane and a twelfth image-side surface near the image plane. The twelfth object-side surface is convex, and the twelfth image-side surface is convex. The thirteenth lens includes a thirteenth object-side surface near the object plane and a thirteenth image-side surface near the image plane. The thirteenth object-side surface is concave, and the thirteenth image-side surface is concave. The fourteenth lens includes a fourteenth object-side surface near the object plane and a fourteenth image-side surface near the image plane. The fourteenth object-side surface is convex, and the fourteenth image-side surface is either convex or concave.

2. The industrial lens according to claim 1, characterized in that, The first lens and the second lens are cemented together, the third lens and the fourth lens are cemented together, and the fifth lens and the sixth lens are cemented together; The eighth lens and the ninth lens are cemented together, and the tenth lens, the eleventh lens and the twelfth lens are cemented together.

3. The industrial lens according to claim 2, characterized in that, The first lens has an optical power of φ11 and an Abbe number of vd11; the second lens has an optical power of φ12 and an Abbe number of vd12; the third lens has an optical power of φ13 and an Abbe number of vd13; the fourth lens has an optical power of φ14 and an Abbe number of vd14; the fifth lens has an optical power of φ15 and an Abbe number of vd15; and the sixth lens has an optical power of φ16 and an Abbe number of vd16. in, ; ； 。 4. The industrial lens according to claim 2, characterized in that, The tenth lens is a positive power lens with an optical power of φ24, the eleventh lens is a negative power lens with an optical power of φ25, the twelfth lens is a positive power lens with an optical power of φ26, and the optical power of the industrial lens is φ. The tenth lens has a refractive index of nd24 and an Abbe number of vd24; the eleventh lens has a refractive index of nd25 and an Abbe number of vd25; and the twelfth lens has a refractive index of nd26 and an Abbe number of vd26. Among them, 0.6514<(φ24 / φ+φ25 / φ+φ26 / φ)<1.0607; nd24<nd25, nd26<nd25, vd24<vd25, vd26<vd25.

5. The industrial lens according to claim 1, characterized in that, The optical power of the seventh lens is φ21, the optical power of the eighth lens is φ22, and the optical power of the industrial lens is φ. Among them, -3.1435<φ21 / φ<-2.5719, 2.0825<φ22 / φ<2.6761.

6. The industrial lens according to claim 1, characterized in that, The moving distance of the second lens group is ZOL, and the distance between the image side surface of the fourteenth lens and the image plane is BFL; Among them, 0.3390≤ZOL / BFL≤0.8787.

7. The industrial lens according to claim 1, characterized in that, The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the fourteenth lens are all glass spherical lenses; The thirteenth lens is a glass aspherical lens.

8. The industrial lens according to claim 1, characterized in that, The industrial lens also includes an aperture stop, which is disposed in the optical path between the ninth lens and the tenth lens.

Images