Lens module, optical system and optical equipment

Abstract

The utility model relates to a lens module, an optical system and optical equipment, the lens module comprises a front fixed lens group, a zoom lens group, a compensation lens group and a rear fixed lens group which are arranged in sequence, the front fixed lens group has negative focal power, the zoom lens group has positive focal power, the compensation lens group has negative focal power, and the rear fixed lens group has positive focal power. The rear fixed lens group has positive focal power, and the positions of the zoom lens group and the compensation lens group can be adjusted. According to the technical scheme, the positions of the zoom lens group and the compensation lens group can be adjusted so as to realize different zooming and focusing on the incident laser beam, so that the laser beam in a certain size range can be output, the size of the output laser beam can be adjusted according to the actual use requirement, and therefore, the size of the laser beam can be adjusted. The lens module is wide in application range.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical systems, and in particular, to a lens module, an optical system, and an optical device. Background Art

[0002] Lasers are highly monochromatic, coherent, directional, and concentrated light sources, making them widely used in laser processing, optical illumination, microlithography, information technology, and biomedicine. However, after homogenization, conventional laser beams often only output a fixed beam size, limiting the application of a single laser system to a single scenario and a narrow range of applications. Utility Model Content

[0003] The purpose of the present disclosure is to provide a lens module, an optical system and an optical device that can be used for laser beam variable magnification output and has a wide range of applications, so as to at least partially solve the above-mentioned technical problems.

[0004] In order to achieve the above-mentioned purpose, according to the first aspect of the present disclosure, a lens module is provided, comprising a front fixed lens group, a zoom lens group, a compensation lens group and a rear fixed lens group arranged in sequence, the front fixed lens group having a negative optical focal length, the zoom lens group having a positive optical focal length, the compensation lens group having a negative optical focal length, and the rear fixed lens group having a positive optical focal length, wherein the positions of the zoom lens group and the compensation lens group are both adjustable.

[0005] Optionally, parameters of the front fixed lens group, the zoom lens group, the compensation lens group and the rear fixed lens group are configured so that the output light diameter of the lens module is 28 mm to 100 mm.

[0006] Optionally, the incident light diameter of the lens module is less than 40 mm.

[0007] Optionally, the incident light divergence angle of the lens module is 0-2°.

[0008] Optionally, the modulation transfer function of the lens module has a full field of view greater than 0.47@16lp / mm.

[0009] Optionally, the front fixed lens group includes a first plano-concave lens.

[0010] Optionally, the optical axis center thickness of the first plano-concave lens is 9.8 mm to 10.2 mm; and / or,

[0011] The curvature radius of the inner concave surface of the first plano-concave lens is 226 mm to 228 mm; and / or,

[0012] The refractive index of the first plano-concave lens is 1.98-2.02; and / or,

[0013] The Abbe number of the first plano-concave lens is 20.2-21.2.

[0014] Optionally, the zoom lens group includes a plano-convex lens and a first meniscus lens located on a side of the plano-convex lens away from the front fixed lens group.

[0015] Optionally, the optical axis center thickness of the plano-convex lens is 9.8 mm to 10.2 mm; and / or,

[0016] The side of the plano-convex lens away from the front fixed lens group is configured as an outward convex surface, and the curvature radius of the outward convex surface is 234 mm to 236 mm; and / or,

[0017] The refractive index of the plano-convex lens is 1.67-1.71; and / or,

[0018] The Abbe number of the plano-convex lens is 52.7-53.7.

[0019] Optionally, the optical axis center thickness of the first meniscus lens is 9.8 mm to 10.2 mm; and / or,

[0020] The first meniscus lens has a first surface facing the plano-convex lens and a second surface facing away from the plano-convex lens, the first surface has a curvature radius of 146 mm to 148 mm, and / or the second surface has a curvature radius of 354 mm to 356 mm; and / or,

[0021] The refractive index of the first meniscus lens is 1.86-1.90; and / or,

[0022] The Abbe number of the first meniscus lens is 40.5-41.5.

[0023] Optionally, the plano-convex lens and the first meniscus lens are capable of moving synchronously, and / or one of the plano-convex lens and the first meniscus lens is capable of moving relative to the other.

[0024] Optionally, the distance between the plano-convex lens and the first meniscus lens is 4.9 mm to 5.1 mm.

[0025] Optionally, the compensation lens group includes a second plano-concave lens and a second meniscus lens located on a side of the second plano-concave lens away from the zoom lens group.

[0026] Optionally, the optical axis center thickness of the second plano-concave lens is 9.8 mm to 10.2 mm; and / or,

[0027] A side of the second plano-concave lens close to the zoom lens group is configured as an inner concave surface, and a curvature radius of the inner concave surface is 234 mm to 236 mm; and / or,

[0028] The refractive index of the second plano-concave lens is 1.93-1.97; and / or,

[0029] The Abbe number of the second plano-concave lens is 17.4-18.4.

[0030] Optionally, the optical axis center thickness of the second meniscus lens is 9.8 mm to 10.2 mm; and / or,

[0031] The second meniscus lens has a first surface facing the second plano-concave lens and a second surface facing away from the second plano-concave lens, the curvature radius of the first surface is 131 mm to 133 mm, and / or the curvature radius of the second surface is 62 mm to 63 mm; and / or,

[0032] The refractive index of the second meniscus lens is 1.90-1.94; and / or,

[0033] The Abbe number of the second meniscus lens is 20.4-21.4.

[0034] Optionally, the second plano-concave lens and the second meniscus lens are capable of moving synchronously, and / or one of the second plano-concave lens and the second meniscus lens is capable of moving relative to the other.

[0035] Optionally, the distance between the second plano-concave lens and the second meniscus lens is 74.6 mm to 74.8 mm.

[0036] Optionally, the rear fixed lens group is a collimating lens group.

[0037] Optionally, the rear fixed lens group includes a third meniscus lens.

[0038] Optionally, the optical axis center thickness of the third meniscus lens is 19.8 mm to 20.2 mm; and / or,

[0039] The third meniscus lens has a first surface facing the compensation lens group and a second surface away from the compensation lens group, the curvature radius of the first surface is 255 mm to 257 mm, and / or the curvature radius of the second surface is 145 mm to 147 mm; and / or,

[0040] The refractive index of the third meniscus lens is 1.93-1.97; and / or,

[0041] The Abbe number of the third meniscus lens is 19.9-20.9.

[0042] Optionally, at least one of the lenses in the front fixed lens group, the zoom lens group, the compensation lens group and the rear fixed lens group is a spherical lens.

[0043] Optionally, the number of the front fixed lens groups is one or more, and / or the number of the rear fixed lens groups is one or more.

[0044] According to a second aspect of the present disclosure, an optical system is provided, comprising the lens module as described above.

[0045] According to a third aspect of the present disclosure, an optical device is provided, comprising the lens module as described above or the optical system as described above.

[0046] Through the above technical solution, the incident laser beam is magnified and focused through the front fixed lens group, zoom lens group, compensation lens group and rear fixed lens group of the lens module in sequence, wherein the positions of the zoom lens group and the compensation lens group can be adjusted to achieve different magnifications and focuses of the incident laser beam, thereby being able to output a laser beam in a certain size range. Therefore, the size of the output laser beam can be adjusted according to actual usage requirements, thereby having a wider range of applicability of the lens module.

[0047] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0049] Figure 1 1 is a schematic diagram of the overall structure of a lens module provided in an exemplary embodiment of the present disclosure, which is set to a short-focus configuration;

[0050] Figure 2 1 is a schematic diagram of the overall structure of a lens module provided in an exemplary embodiment of the present disclosure, which is set to a mid-focus configuration;

[0051] Figure 3 1 is a schematic diagram of the overall structure of a lens module provided in an exemplary embodiment of the present disclosure, which is set to a telephoto configuration;

[0052] Figure 4 is an MTF curve diagram of the lens module provided in an exemplary embodiment of the present disclosure set to a short-focus configuration;

[0053] Figure 5 is an MTF curve diagram of a lens module provided in an exemplary embodiment of the present disclosure set to a mid-focus configuration;

[0054] Figure 6 is an MTF curve diagram of the lens module provided in an exemplary embodiment of the present disclosure when it is set to a telephoto configuration;

[0055] Figure 7 is an image plane illumination diagram of a lens module provided in an exemplary embodiment of the present disclosure set to a short-focus configuration;

[0056] Figure 8 is an image plane illumination diagram of a lens module provided in an exemplary embodiment of the present disclosure when the lens module is set to a mid-focus configuration;

[0057] Figure 9 1 is an image plane illumination diagram when the lens module provided in an exemplary embodiment of the present disclosure is set to a telephoto configuration.

[0058] Description of Reference Numerals

[0059] 1. Lens module; 2. Front fixed lens group; 21. First plano-concave lens; 3. Zoom lens group; 31. Plano-convex lens; 32. First meniscus lens; 4. Compensating lens group; 41. Second plano-concave lens; 42. Second meniscus lens; 5. Rear fixed lens group; 51. Third meniscus lens. DETAILED DESCRIPTION

[0060] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0061] In this disclosure, unless otherwise specified, "inside" and "outside" refer to the inside and outside of the corresponding component's outline; "far" and "near" refer to the spatial distance of the corresponding component relative to another component. Furthermore, the terms "first," "second," and so on, used in this disclosure, are intended to distinguish one element from another and do not convey sequential or significant meanings. In the following description, unless otherwise indicated, identical numerals in different figures represent identical or similar elements.

[0062] The lens module, optical system and optical device in exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0063] According to the first aspect of the present disclosure, referring to Figures 1 to 9 The present disclosure provides a lens module 1, which includes a front fixed lens group 2, a zoom lens group 3, a compensation lens group 4 and a rear fixed lens group 5 arranged in sequence, the front fixed lens group 2 has a negative optical focal length, the zoom lens group 3 has a positive optical focal length, the compensation lens group 4 has a negative optical focal length, and the rear fixed lens group 5 has a positive optical focal length, wherein the positions of the zoom lens group 3 and the compensation lens group 4 can be adjusted.

[0064] Through the above technical solution, the incident laser beam is magnified and focused through the front fixed lens group 2, zoom lens group 3, compensation lens group 4 and rear fixed lens group 5 of the lens module 1 in sequence, wherein the positions of the zoom lens group 3 and the compensation lens group 4 can be adjusted to achieve different magnifications and focuses of the incident laser beam, thereby being able to output a laser beam in a certain size range, and thus the size of the output laser beam can be adjusted according to actual usage requirements. Thus, the lens module 1 has a wider range of applicability.

[0065] Among them, the lens module is an optical component that combines one or more lenses and usually also contains other optical elements. Its purpose is to achieve specific optical functions, such as focusing, imaging, beam shaping, etc. In an exemplary application scenario, in order to obtain a larger laser intensity and various large target sizes in laser processing or laser projection lighting systems, it is necessary to regulate the large-aperture laser beam. For example, in a laser marking machine, the lens module can focus the laser beam on the surface of the workpiece to make the mark clearer and finer. Different lens modules can achieve different marking effects. For example, a small-spot lens module can be used to make high-precision text, patterns, QR codes and other marks; a large-spot lens module can be used for large-area coloring or grayscale marking. Or a laser cutting machine, the lens module focuses the laser beam on the surface of the workpiece, increases the energy density of the laser, and enables the workpiece to be cut quickly and accurately. Lens modules with different focal lengths can be used for cutting workpieces of different thicknesses and materials. For example, a short-focal-length lens module can produce a smaller light spot, which is suitable for cutting thinner materials and can achieve a finer cutting effect; a long-focal-length lens module can be used to cut thicker workpieces, allowing the laser to better penetrate the material. For example, the present disclosure provides a lens module 1 that can achieve a locking pin or amplified output of an incident laser beam with a maximum diameter (or maximum aperture) of 40 mm and a divergence angle of 0 to 2°. Therefore, the lens module 1 provided by the present disclosure can meet the zoom and focusing requirements of large-aperture laser beams and has greater applicability. In addition, the modulation transfer function of the lens module provided by the present disclosure has a full field of view greater than 0.47@16lp / mm, so it has strong resolution and analysis power, which can improve imaging clarity.

[0066] For example, in some embodiments, referring to Figures 1 to 9The parameters of the front fixed lens group 2, the zoom lens group 3, the compensating lens group 4, and the rear fixed lens group 5 are configured so that the output light diameter of the lens module 1 is 28mm~100mm, wherein the output light is the light output after the input light is processed by the lens groups of the lens module 1. The input light passes through the front fixed lens group 2, the zoom lens group 3, the compensating lens group 4, and the rear fixed lens group 5 in sequence, and is focused or diverged by the input light, and then output as the output light through the rear fixed lens group 5. In this way, the lens module 1 can achieve continuous variable magnification focusing of the above-mentioned incident laser beam, with a wider adjustable range, and can achieve the output of a larger-sized collimated laser beam. In addition, at least one of the lenses in the front fixed lens group 2, the zoom lens group 3, the compensating lens group 4, and the rear fixed lens group 5 is a spherical lens. The manufacturing process of spherical lenses is relatively mature and the production cost is low. Since part of its surface is part of a sphere, it can be processed using traditional grinding and polishing techniques, which is easy to mass-produce. At the same time, the design and optical performance prediction of spherical lenses are relatively simple, and their optical characteristics can be described using simple mathematical models, facilitating design and verification. Therefore, the lens module 1 provided by the present disclosure is simple to manufacture and has low production costs. It is also easy to adjust and has high zoom, focusing, and collimation quality. It is understood that in some other possible alternative embodiments, the lenses in the front fixed lens group 2, the zoom lens group 3, the compensating lens group 4, and the rear fixed lens group 5 can also be free-form surface lenses, and the present disclosure is not limited to this.

[0067] Among them, the parameters of the front fixed lens group 2, the zoom lens group 3, the compensation lens group 4 and the rear fixed lens group 5 include but are not limited to at least one of the thickness of the optical axis center of the lens, the curvature radius of the lens surface, the refractive index of the lens, and the Abbe number of the lens.

[0068] In some embodiments, reference Figures 1 to 3 , the front fixed lens assembly 2 can include a first plano-concave lens 21. Thus, when the incident laser beam passes through the concave surface of the first plano-concave lens 21, the laser beam is diverged, i.e., the laser beam path is refracted away from the axial direction, thereby widening the laser beam. Furthermore, the first plano-concave lens 21 can be used to correct aberrations to a certain extent, thereby improving the imaging quality of the overall lens module 1.

[0069] The optical axis center thickness of the first plano-concave lens 21 can be 9.8mm~10.2mm, the curvature radius of the inner concave surface of the first plano-concave lens 21 can be 226mm~228mm, the refractive index of the first plano-concave lens 21 can be 1.98~2.02, and the Abbe number of the first plano-concave lens 21 can be 20.2~21.2.

[0070] The present disclosure exemplarily sets the optical axis center thickness of the first plano-concave lens 21 to 10 mm, the curvature radius of the inner concave surface to 227.085 mm, and the refractive index of the selected material is 2 and the Abbe number is 20.7.

[0071] In some embodiments, reference Figures 1 to 3 , the zoom lens group 3 may include a plano-convex lens 31 and a first meniscus lens 32 located on the side of the plano-convex lens 31 away from the front fixed lens group 2, wherein the zoom lens group 3 has positive optical power. In this way, when the incident laser beam passes through the zoom lens group 3, the laser beam will be converged, that is, the laser beam path will be refracted close to the axis direction. The combination of the plano-convex lens 31 and the first meniscus lens 32 can adjust the focal length of the entire optical system and achieve more precise focusing. In addition, the combination of the plano-convex lens 31 and the first meniscus lens 32 can achieve the same effect as a lens with a more complex structure (such as a free-form surface lens), thereby reducing the cost of the lens module 1. At the same time, the combined use of the plano-convex lens 31 and the first meniscus lens 32 can reduce the number of lenses in the lens module 1, reduce space occupancy, and reduce assembly costs.

[0072] In some embodiments, reference Figures 1 to 3 The optical axis center thickness of the plano-convex lens 31 can be 9.8 mm to 10.2 mm, the side of the plano-convex lens 31 away from the front fixed lens group 2 is constructed as a convex surface, the curvature radius of the convex surface can be 234 mm to 236 mm, the refractive index of the plano-convex lens 31 can be 1.67 to 1.71, and the Abbe number of the plano-convex lens 31 can be 52.7 to 53.7.

[0073] The optical axis center thickness of the first meniscus lens 32 can be 9.8mm~10.2mm. The first meniscus lens 32 has a first surface facing the plano-convex lens 31 and a second surface away from the plano-convex lens 31. The curvature radius of the first surface can be 146mm~148mm, and the curvature radius of the second surface can be 354mm~356mm. The refractive index of the first meniscus lens 32 can be 1.86~1.90, and the Abbe number of the first meniscus lens 32 can be 40.5~41.5.

[0074] The present disclosure exemplarily sets the optical axis center thickness of the plano-convex lens 31 to 10 mm, the curvature radius of the convex surface to 235 mm, the refractive index of the selected material to 1.69, and the Abbe number to 53.2; the optical axis center thickness of the first meniscus lens 32 is 10 mm, the curvature radius of the first surface is 147.23 mm, the curvature radius of the second surface is 355.011 mm, the refractive index of the selected material is 1.88, and the Abbe number is 41.

[0075] Among them, the plano-convex lens 31 and the first meniscus lens 32 can move synchronously. For example, the distance between the two can be set in advance. During the focusing process, the plano-convex lens 31 and the first meniscus lens 32 can be moved synchronously to simplify the adjustment process, facilitate operation, and have a simple structure.

[0076] Alternatively, one of the plano-convex lens 31 and the first meniscus lens 32 can be moved relative to the other. Thus, by adjusting the distance between the plano-convex lens 31 and the first meniscus lens 32, the effective focal length of the zoom lens assembly 3 can be changed. Furthermore, by fine-tuning the distance between the plano-convex lens 31 and the first meniscus lens 32, aberrations can be optimized, imaging quality can be improved, and the focusing degree of the laser beam can be controlled to achieve laser beam shaping.

[0077] Alternatively, according to actual needs, the plano-convex lens 31 and the first meniscus lens 32 can be moved synchronously, or the plano-convex lens 31 and the first meniscus lens 32 can be moved relative to each other, so that the operation is more flexible, and the aberration can be optimized, the imaging quality can be improved, and the focusing degree of the laser beam can be controlled to achieve the shaping of the laser beam.

[0078] In some embodiments, reference Figures 1 to 3 The distance between the plano-convex lens 31 and the first meniscus lens 32 can be 4.9 mm to 5.1 mm. When the plano-convex lens 31 and the first meniscus lens 32 are capable of relative movement, this distance range can be the range of movement between the plano-convex lens 31 and the first meniscus lens 32. When the plano-convex lens 31 and the first meniscus lens 32 are relatively fixed and move synchronously, any value within this range can be pre-selected to set the fixed distance between the plano-convex lens 31 and the first meniscus lens 32. For example, the present disclosure exemplarily sets the fixed distance between the plano-convex lens 31 and the first meniscus lens 32 to 5 mm.

[0079] In some embodiments, reference Figures 1 to 3 , the compensation lens group 4 may include a second plano-concave lens 41 and a second meniscus lens 42 located on the side of the second plano-concave lens 41 away from the zoom lens group 3. The compensation lens group 4 has a negative optical focal length. In this way, when the incident laser beam passes through the compensation lens group 4, the laser beam will be diverged, that is, the laser beam path will be refracted away from the axial direction, thereby achieving a specific beam shape, such as laser beam widening, to adjust the focal length. The combination of the plano-concave lens and the second meniscus lens 42 can significantly reduce aberrations, such as spherical aberration and chromatic aberration. The combination of the second plano-concave lens 41 and the second meniscus lens 42 can compensate for their respective aberrations, thereby improving the imaging quality of the lens module 1. At the same time, through the combination of the second plano-concave lens 41 and the second meniscus lens 42, the overall structure is more compact, and its use can reduce the number of lenses in the lens module 1, reduce space occupancy, and reduce assembly costs.

[0080] In some embodiments, reference Figures 1 to 3 The optical axis center thickness of the second plano-concave lens 41 can be 9.8 mm to 10.2 mm, the side of the second plano-concave lens 41 close to the zoom lens group 3 is constructed as an inner concave surface, the curvature radius of the inner concave surface is 234 mm to 236 mm, the refractive index of the second plano-concave lens 41 can be 1.93 to 1.97, and the Abbe number of the second plano-concave lens 41 can be 17.4 to 18.4.

[0081] The optical axis center thickness of the second meniscus lens 42 can be 9.8mm~10.2mm. The second meniscus lens 42 has a first surface facing the second plano-concave lens 41 and a second surface away from the second plano-concave lens 41. The curvature radius of the first surface can be 131mm~133mm, the curvature radius of the second surface can be 62mm~63mm, the refractive index of the second meniscus lens 42 can be 1.90~1.94, and the Abbe number of the second meniscus lens 42 can be 20.4~21.4.

[0082] The present disclosure exemplarily sets the optical axis center thickness of the second plano-concave lens 41 to 10 mm, the curvature radius of the inner concave surface to 235.001 mm, the refractive index of the selected material to 1.95, and the Abbe number to 17.9; the optical axis center thickness of the second meniscus lens 42 is 10 mm, the curvature radius of the first surface is 132.116 mm, the curvature radius of the second surface is 62.526 mm, the refractive index of the selected material to 1.92, and the Abbe number to 20.9.

[0083] Among them, the second plano-concave lens 41 and the second meniscus lens 42 can move synchronously. For example, the distance between the two can be set in advance. During the focusing process, the second plano-concave lens 41 and the second meniscus lens 42 can be moved synchronously to simplify the adjustment process, facilitate operation, and have a simple structure.

[0084] Alternatively, one of the second plano-concave lens 41 and the second meniscus lens 42 can be moved relative to the other. Thus, by adjusting the distance between the second plano-concave lens 41 and the second meniscus lens 42, the effective focal length of the compensation lens assembly 4 can be varied. Furthermore, by fine-tuning the distance between the second plano-concave lens 41 and the second meniscus lens 42, focusing characteristics can be optimized, for example, achieving a smoother depth of focus transition or achieving an ideal focusing effect in a specific application.

[0085] Alternatively, according to actual needs, the second plano-concave lens 41 and the second meniscus lens 42 can be moved synchronously, or the second plano-concave lens 41 and the second meniscus lens 42 can be moved relative to each other, so as to be more flexible in operation and to optimize the focusing characteristics, for example, to achieve a smoother depth of focus transition, or to achieve an ideal focusing effect in specific applications.

[0086] In some embodiments, reference Figures 1 to 3 The distance between the second plano-concave lens 41 and the second meniscus lens 42 can be 74.6 mm to 74.8 mm. When the second plano-concave lens 41 and the second meniscus lens 42 are relatively movable, this distance range can be the range of movement between the second plano-concave lens 41 and the second meniscus lens 42. When the second plano-concave lens 41 and the second meniscus lens 42 are relatively fixed and move synchronously, any value within this range can be pre-selected to set the fixed distance between the second plano-concave lens 41 and the second meniscus lens 42. For example, the present disclosure exemplarily sets the fixed distance between the second plano-concave lens 41 and the second meniscus lens 42 to 74.745 mm.

[0087] In some embodiments, the rear fixed lens group 5 can be configured as a collimating lens group. Thus, after the incident laser beam passes through the front fixed lens group 2, the zoom lens group 3, and the compensating lens group 4, it is zoomed and focused, and then collimated by the rear fixed lens group 5 to output a high-quality laser beam. Collimation refers to converting light from a point source into a parallel beam, or correcting a divergent beam into a parallel beam.

[0088] In some embodiments, reference Figures 1 to 3 The rear fixed lens group 5 may include a third meniscus lens 51 having positive optical power. In this case, the divergent laser beam passing through the compensation lens group 4 is focused by the third meniscus lens 51 into a beam parallel to the principal axis. It is understood that the rear fixed lens group 5 may also include a free-form surface lens or a plano-convex lens 31, and the present disclosure is not limited thereto.

[0089] In some embodiments, reference Figures 1 to 3 The optical axis center thickness of the third meniscus lens 51 can be 19.8mm~20.2mm, the third meniscus lens 51 has a first surface facing the compensation lens group 4 and a second surface away from the compensation lens group 4, the curvature radius of the first surface can be 255mm~257mm, the curvature radius of the second surface can be 145mm~147mm, the refractive index of the third meniscus lens 51 can be 1.93~1.97, and the Abbe number of the third meniscus lens 51 can be 19.9~20.9.

[0090] The present disclosure exemplarily sets the optical axis center thickness of the third meniscus lens 51 to 20 mm, the curvature radius of the first surface to 256.744 mm, the curvature radius of the second surface to 144.996 mm, the refractive index of the selected material to 1.95, and the Abbe number to 20.4.

[0091] The present disclosure exemplarily illustrates the overall structural schematic diagram, MTF curve diagram, and image plane illumination diagram of the lens module 1 based on the above-mentioned lens types and parameters. Specifically, the spacing between the front fixed lens group 2 and the zoom lens group 3 is an adjustable distance a, the spacing between the zoom lens group 3 and the compensation lens group 4 is an adjustable distance b, and the spacing between the compensation lens group 4 and the rear fixed lens group 5 is an adjustable distance c. By adjusting the above-mentioned adjustable distances a, b, and c, a continuous variable magnification and focusing output of the incident laser beam can be achieved.

[0092] refer to Figure 1 、 Figure 4 and Figure 7 The lens module 1 is exemplarily constructed as a short-focus configuration, with adjustable distances a, b, and c being 215.796 mm, 108.213 mm, and 106.292 mm, respectively. The magnification in the short-focus case is 0.7× and the focal length is 420 mm. Figure 4 and Figure 7 The modulation transfer function (MTF) curve and image plane illumination diagram of the lens module 1 under short-focus conditions are respectively shown. The short-focus output spot diameter is 28mm, the full field divergence angle is less than 2°, and the MTF reaches >0.5@18lp / mm, successfully reducing the 40mm diameter beam to 28mm, and achieving an MTF close to the diffraction limit and a high collimation of less than 2°.

[0093] refer to Figure 2 、 Figure 5 and Figure 8 The lens module 1 is exemplarily constructed as a mid-focus configuration, with adjustable distances a, b, and c being 110.457 mm, 135.014 mm, and 184.909 mm, respectively. The magnification of the mid-focus configuration is 1.3×, and the focal length is 740 mm. Figure 5 and Figure 8 The modulation transfer function (MTF) curve and image plane illumination diagram of the lens module 1 at mid-focus are respectively shown. The output spot diameter at mid-focus is 52mm, the full field divergence angle is less than 1.5°, and the MTF reaches >0.5@18lp / mm. The 40mm diameter beam is successfully expanded to 52mm, with an MTF close to the diffraction limit and a high collimation of less than 1.5°.

[0094] refer to Figure 3 、 Figure 6 and Figure 9 The lens module 1 is exemplarily constructed as a telephoto configuration, with adjustable distances a, b, and c being 5.696 mm, 209.461 mm, and 215.286 mm, respectively. The magnification ratio in the telephoto configuration is 2.5×, and the focal length is 1400 mm. Figure 6 and Figure 9The modulation transfer function (MTF) curve and image plane illumination diagram of the lens module 1 in the telephoto case are respectively shown. The telephoto output spot diameter is 100mm, the full field of view divergence angle is less than 1°, and the MTF reaches >0.47@18lp / mm. It successfully expands the 40mm diameter beam to 100mm, and has an MTF close to the diffraction limit and a high collimation of less than 1°.

[0095] In addition, in another exemplary application scenario, the lens module 1 can also be used for continuous zoom focusing of an incident laser beam with a diameter of 8 mm and a divergence angle of 0-2°. The output light diameter ranges from 28 mm to 100 mm, and the magnification is 3.5× to 12.5×. It is understood that the above adjustment process can be achieved by adjusting the distances a, b, and c. Table 1 below shows several examples of output light diameters of 28 mm to 100 mm and the corresponding values ​​of the distances a, b, and c.

[0096]

[0097] Table 1

[0098] In some embodiments, the number of front fixed lens groups 2 can be one or more, and / or the number of rear fixed lens groups 5 can be one or more. In this way, the overall imaging quality of the lens module 1 can be improved by increasing the number of either the front fixed lens group 2 or the rear fixed lens group 5. For example, when the number of front fixed lens groups 2 is multiple and the front fixed lens group 2 includes a first plano-concave lens 21, the lens module 1 provided by the present disclosure can have multiple first plano-concave lenses 21 to improve the overall imaging quality of the lens module 1. In addition, for example, when the number of rear fixed lens groups 5 is multiple and the rear fixed lens group 5 includes a third meniscus lens 51, the lens module 1 provided by the present disclosure can have multiple third meniscus lenses 51 to improve the overall imaging quality of the lens module 1.

[0099] According to a second aspect of the present disclosure, an optical system is provided, comprising the lens module 1 described above. This optical system possesses all the beneficial effects of the lens module 1 described above, which are not further detailed herein. The optical system may be, for example, a laser system (for laser cutting, laser marking, or laser measurement) or an imaging system, which is not specifically limited in this disclosure.

[0100] Exemplarily, when the lens module 1 disclosed in the present invention is applied to a laser marking system, the zoom lens group 3 and the compensation lens group 4 are moved to achieve variable magnification output of the incident laser beam. For example, moving the zoom lens group 3 and the compensation lens group 4 toward the front fixed lens group 2 can be used to amplify the output incident laser beam, that is, to amplify the diameter of the output light. Moving the zoom lens group 3 and the compensation lens group 4 toward the rear fixed lens group 5 can be used to reduce the incident laser beam, that is, to reduce the diameter of the output light, so that the diameter of the output light can be adjusted according to actual usage requirements to meet the laser marking requirements.

[0101] Among them, the zoom lens group 3 and the compensation lens group 4 can be driven to move by a transmission device. For example, the transmission device can include a transmission motor connected to the zoom lens group 3 and the compensation lens group 4 respectively. The transmission motor is driven by a power supply to realize the movement of the zoom lens group 3 and the compensation lens group 4. At the same time, a linear encoder can be used to record the displacement of the zoom lens group 3 and the compensation lens group 4 to achieve precise control of the movement and improve the precision of laser processing.

[0102] According to a third aspect of the present disclosure, an optical device is provided, comprising the lens module 1 or the optical system described above. The optical device has all the beneficial effects of the lens module 1 or the optical system described above. When the optical device comprises the lens module 1, the optical device may further comprise the transmission device described above for adjusting the lens module 1, which is not further described herein. The optical device may be, for example, a laser projector, a laser illumination system, or an optical experimental platform, and the present disclosure does not specifically limit this.

[0103] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0105] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A lens module, characterized in that: It includes a front fixed lens group, a zoom lens group, a compensating lens group and a rear fixed lens group arranged in sequence, the front fixed lens group has a negative optical focal length, the zoom lens group has a positive optical focal length, the compensating lens group has a negative optical focal length, and the rear fixed lens group has a positive optical focal length, wherein the positions of the zoom lens group and the compensating lens group are both adjustable.

2. The lens module according to claim 1, wherein: The parameters of the front fixed lens group, the zoom lens group, the compensation lens group and the rear fixed lens group are configured so that the output light diameter of the lens module is 28 mm to 100 mm.

3. The lens module according to claim 1, wherein: The incident light diameter of the lens module is less than 40 mm.

4. The lens module according to claim 1, wherein: The incident light divergence angle of the lens module is 0-2°.

5. The lens module according to claim 1, wherein: The modulation transfer function of the lens module is greater than 0.47@16lp / mm over the entire field of view.

6. The lens module according to any one of claims 1 to 5, characterized in that: The front fixed lens group includes a first plano-concave lens.

7. The lens module according to claim 6, wherein: The optical axis center thickness of the first plano-concave lens is 9.8 mm to 10.2 mm; and / or, The curvature radius of the inner concave surface of the first plano-concave lens is 226 mm to 228 mm; and / or, The refractive index of the first plano-concave lens is 1.98-2.02; and / or, The Abbe number of the first plano-concave lens is 20.2-21.

2.

8. The lens module according to any one of claims 1 to 5, characterized in that: The zoom lens group includes a plano-convex lens and a first meniscus lens located on a side of the plano-convex lens away from the front fixed lens group.

9. The lens module according to claim 8, wherein: The optical axis center thickness of the plano-convex lens is 9.8 mm to 10.2 mm; and / or, The side of the plano-convex lens away from the front fixed lens group is configured as an outward convex surface, and the curvature radius of the outward convex surface is 234 mm to 236 mm; and / or, The refractive index of the plano-convex lens is 1.67-1.71; and / or, The Abbe number of the plano-convex lens is 52.7-53.

7.

10. The lens module according to claim 8, wherein: The optical axis center thickness of the first meniscus lens is 9.8 mm to 10.2 mm; and / or, The first meniscus lens has a first surface facing the plano-convex lens and a second surface facing away from the plano-convex lens, wherein the radius of curvature of the first surface is 146 mm to 148 mm, and / or the radius of curvature of the second surface is 354 mm to 356 mm; and / or, The refractive index of the first meniscus lens is 1.86-1.90; and / or, The Abbe number of the first meniscus lens is 40.5-41.

5.

11. The lens module according to claim 8, wherein: The plano-convex lens and the first meniscus lens are capable of moving synchronously, and / or one of the plano-convex lens and the first meniscus lens is capable of moving relative to the other.

12. The lens module according to claim 8, wherein: The distance between the plano-convex lens and the first meniscus lens is 4.9 mm to 5.1 mm.

13. The lens module according to any one of claims 1 to 5, characterized in that: The compensation lens group includes a second plano-concave lens and a second meniscus lens located on a side of the second plano-concave lens away from the zoom lens group.

14. The lens module according to claim 13, wherein: The optical axis center thickness of the second plano-concave lens is 9.8 mm to 10.2 mm; and / or, A side of the second plano-concave lens close to the zoom lens group is configured as an inner concave surface, and a curvature radius of the inner concave surface is 234 mm to 236 mm; and / or, The refractive index of the second plano-concave lens is 1.93-1.97; and / or, The Abbe number of the second plano-concave lens is 17.4-18.

4.

15. The lens module according to claim 13, wherein: The optical axis center thickness of the second meniscus lens is 9.8 mm to 10.2 mm; and / or, The second meniscus lens has a first surface facing the second plano-concave lens and a second surface facing away from the second plano-concave lens, wherein the radius of curvature of the first surface is 131 mm to 133 mm, and / or the radius of curvature of the second surface is 62 mm to 63 mm; and / or, The refractive index of the second meniscus lens is 1.90-1.94; and / or, The Abbe number of the second meniscus lens is 20.4-21.

4.

16. The lens module according to claim 13, wherein: The second plano-concave lens and the second meniscus lens are capable of moving synchronously, and / or one of the second plano-concave lens and the second meniscus lens is capable of moving relative to the other.

17. The lens module according to claim 13, wherein: The distance between the second plano-concave lens and the second meniscus lens is 74.6 mm to 74.8 mm.

18. The lens module according to any one of claims 1 to 5, characterized in that: The rear fixed lens group is a collimating lens group.

19. The lens module according to claim 18, wherein: The rear fixed lens group includes a third meniscus lens.

20. The lens module according to claim 19, wherein: The optical axis center thickness of the third meniscus lens is 19.8 mm to 20.2 mm; and / or, The third meniscus lens has a first surface facing the compensation lens group and a second surface facing away from the compensation lens group, wherein the radius of curvature of the first surface is 255 mm to 257 mm, and / or the radius of curvature of the second surface is 145 mm to 147 mm; and / or, The refractive index of the third meniscus lens is 1.93-1.97; and / or, The Abbe number of the third meniscus lens is 19.9-20.

9.

21. The lens module according to claim 1, wherein: At least one of the lenses in the front fixed lens group, the zoom lens group, the compensation lens group, and the rear fixed lens group is a spherical lens.

22. The lens module according to claim 1, wherein: The number of the front fixed lens groups is one or more, and / or the number of the rear fixed lens groups is one or more.

23. An optical system, characterized in that A lens module comprising any one of claims 1-22.

24. An optical device, characterized in that: The lens module comprises any one of claims 1 to 22 or the optical system according to claim 23.

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