Lens assembly and laser device

Abstract

The utility model relates to a lens assembly and laser equipment, the lens assembly comprises an area light source, a first optical element, a second optical element and a third optical element which are sequentially arranged at intervals, the light emitting area of the area light source is 5 mm2-30 mm2, the area light source is used for emitting light beams, and the first optical element is used for adjusting the divergence angle of the light beams; the second optical element is used for adjusting the collimation degree of the light beam; the third optical element focuses the light beam. According to the technical scheme, the problems that traditional laser equipment is large in energy loss and high in cost are effectively solved; the number of internal elements is large, and the assembling difficulty is large.

Description

Technical Field

[0001] The present application relates to the field of laser technology applications, and in particular to a lens assembly and laser equipment. Background Art

[0002] Laser equipment mainly includes laser marking machines, laser welding machines and laser cutting machines, which are used to mark, weld and cut products respectively. At present, laser diodes are usually point light sources with low power. It is usually necessary to set up multiple diodes in the laser equipment to synthesize the required laser beam. This makes the energy loss of laser equipment large and the cost high; in addition, the number of components is large and the assembly is difficult. Utility Model Content

[0003] The present application provides a lens assembly and a laser device to solve the technical problems of traditional laser devices, such as large energy loss and high cost, large number of internal components and high assembly difficulty.

[0004] To this end, in the first aspect, the embodiment of the present application provides a lens assembly, which includes a surface light source, a first optical element, a second optical element and a third optical element arranged in sequence, and the light emitting area of ​​the surface light source is 5mm 2 ~30mm 2 The surface light source is used to emit a light beam, the first optical element is used to adjust the divergence angle of the light beam; the second optical element is used to adjust the collimation of the light beam; and the third optical element is used to focus the light beam.

[0005] In a possible implementation manner, the light emission angle of the surface light source is less than or equal to 5°; and / or,

[0006] The wavelength of the light from the surface light source is 400nm to 500nm.

[0007] In a possible implementation manner, the focal length of the first optical element is -400 mm to -300 mm.

[0008] In a possible implementation manner, the focal length of the second optical element is 50 mm to 70 mm; and / or,

[0009] The focal length of the third optical element is 45 mm to 65 mm; and / or,

[0010] The spot area of ​​the lens assembly at the focus is 0.45mm 2 ~0.55mm 2 .

[0011] In a possible implementation manner, a fourth optical element is further included. The fourth optical element is disposed between the surface light source and the first optical element, and is used to enlarge the radiation area of ​​the light beam.

[0012] In a possible implementation, the first optical element is used to perform fast- and slow-axis shaping and fiber collimation adjustment on the light beam amplified by the fourth optical element.

[0013] In a possible implementation manner, the focal length of the fourth optical element is -30 mm to -10 mm.

[0014] In a possible implementation manner, the distance between the fourth optical element and the surface light source is 12 mm to 18 mm; and / or,

[0015] The distance between the first optical element and the fourth optical element is 5 mm to 9 mm; and / or,

[0016] The distance between the second optical element and the first optical element is 16.6 mm to 26.6 mm; and / or,

[0017] The distance between the third optical element and the second optical element is 6 mm to 12 mm.

[0018] In the second aspect, the present application also provides a laser device, which includes a shell and a lens assembly as described above, the shell having an emitting end and a light emitting end that are relatively arranged, the lens assembly is arranged in the shell, the surface light source of the lens assembly is located at the emitting end, and the third optical element of the lens assembly is located at the light emitting end.

[0019] In a possible implementation manner, a cooling component is further included, and the cooling component is disposed around the shell.

[0020] According to the lens assembly and laser device provided in the embodiment of the present application, the lens assembly includes a surface light source, a first optical element, a second optical element and a third optical element which are arranged in sequence, and the light emitting area of ​​the surface light source is 5mm 2 ~30mm 2, the surface light source is used to emit a light beam, the first optical element is used to adjust the divergence angle of the light beam; the second optical element is used to adjust the collimation of the light beam; the third optical element is used to focus the light beam. The technical solution of the present application selects a surface light source as a laser source to increase the light output area, increase the luminous flux entering the first optical element, and thus increase the total amount of light passing through the lens assembly. At the same time, in view of the characteristics of the surface light source such as a large light output area and a large light beam divergence angle, at least three optical elements are sequentially arranged on the subsequent optical path, so as to obtain a target light beam with high optical power and a moderate spot size through the coordinated cooperation of the three optical elements and the surface light source. Specifically, the divergence angle of the initial light beam can be adjusted by the first optical element to ensure that the divergence angles of the light beam on the major axis and the minor axis of the first optical element are consistent, to avoid excessive divergence in one direction and light loss, and to improve the utilization rate of light energy; the collimation of the light beam emitted from the first optical element can be adjusted by the second optical element, so that the light beam can propagate along a preset optical path, and the light supply accuracy and reliability of the lens assembly can be improved; at the same time, the light beam can be focused by the third optical element to reduce the size of the collimated light beam and form a target light spot for the operation, so as to facilitate subsequent operations such as marking, drilling, welding or cutting of the product, and improve the processing effect; in addition, the overall length of the lens assembly is effectively shortened through the coordinated cooperation of the third optical element and the second optical element, and a miniaturized layout is achieved. Compared with traditional laser equipment that needs to set up multiple point light sources to synthesize the required light beam, this embodiment uses a surface light source to provide the required total light amount, effectively avoiding the need to set up multiple point light sources to achieve laser processing, reducing the difficulty of assembling laser equipment and improving assembly efficiency; and, with the assistance of at least three optical elements cooperating with it, the light beam emitted from the surface light source can be fully utilized, greatly reducing light energy loss and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments that conform to the present application, and are used together with the specification to explain the principles of the present application. In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can also be obtained based on these drawings without paying creative labor. One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute a proportional limitation.

[0022] Figure 1 A schematic diagram of the three-dimensional structure of a lens assembly provided in an embodiment of the present application;

[0023] Figure 2 A schematic diagram of the structure of the laser device provided in an embodiment of the present application.

[0024] Description of reference numerals:

[0025] 100, surface light source; 200, first optical element; 300, second optical element; 400, third optical element; 500, fourth optical element;

[0026] 10. Shell; 11. Transmitter; 12. Light output end; 20. Cooling assembly; 21. Coil; 22. Water inlet pipe; 23. Water outlet pipe; 24. Cooling source;

[0027] 1. Beam. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0029] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, but those of ordinary skill in the art can appreciate the applicability of other processes and / or the use of other materials.

[0030] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0031] See also Figure 1 The embodiment of the present application provides a lens assembly, which includes a surface light source 100, a first optical element 200, a second optical element 300 and a third optical element 400 arranged in sequence, and the light emitting area of ​​the surface light source 100 is 5mm 2 ~30mm 2 The surface light source 100 is used to emit the light beam 1 ; the first optical element 200 is used to adjust the divergence angle of the light beam 1 ; the second optical element 300 is used to adjust the collimation of the light beam 1 ; and the third optical element 400 is used to focus the light beam 1 .

[0032] In this embodiment, the surface light source 100 is selected as the laser source to increase the light output area and the light flux entering the first optical element 200, thereby increasing the total amount of light passing through the lens assembly. At the same time, in view of the large light output area and large divergence angle of the light beam 1 of the surface light source 100, at least three optical elements are sequentially arranged on the optical path thereafter, so as to obtain the target light beam 1 with high optical power and moderate spot size through the coordinated cooperation of the three optical elements and the surface light source 100. Specifically, the divergence angle of the initial light beam 1 can be adjusted through the first optical element 200 to ensure that the divergence angles of the light beam 1 on the major axis and the minor axis of the first optical element 200 are consistent, to avoid excessive divergence in one direction to form light loss, and to improve the utilization rate of light energy; the collimation of the light beam 1 emitted from the first optical element 200 can be adjusted through the second optical element 300, so that the light beam 1 can be propagated along a preset optical path, thereby improving the light supply accuracy and reliability of the lens assembly; at the same time, the light beam 1 can be focused through the third optical element 400 to reduce the size of the collimated light beam 1 to form a target light spot for operation, so as to facilitate subsequent operations such as marking, drilling, welding or cutting of the product, thereby improving the processing effect; in addition, through the coordinated cooperation of the third optical element 400 and the second optical element 300, the overall length of the lens assembly is effectively shortened, and a miniaturized layout is achieved. Compared with traditional laser equipment that needs to set up multiple point light sources to synthesize the required light beam 1, this embodiment uses a surface light source 100 to provide the required total light amount, effectively avoiding the need to set up multiple point light sources to achieve laser processing, reducing the difficulty of assembling laser equipment, and improving assembly efficiency; and, with the assistance of at least three optical elements cooperating with it, the light beam 1 emitted from the surface light source 100 can be fully utilized, greatly reducing light energy loss and reducing costs.

[0033] Specifically, the lens assembly is configured as a combination component including at least a surface light source 100, a first optical element 200, a second optical element 300 and a third optical element 400. The surface light source 100 can be a laser diode, and the power of a single laser diode is between 0W and 22W. The specific working power can be adjusted according to actual processing requirements. For example, a high-power surface light source 100 of 22W can be selected for products with greater hardness, and a low-power surface light source 100 of about 5W can be selected for products with less hardness to further reduce the waste of light energy. In addition, the light-emitting area of ​​the surface light source 100 can be selected according to actual needs. For example, a larger light-emitting area such as 30mm can be selected for hard products. 2 For conventional products, you can choose a moderate luminous area such as 15mm 2 For soft products, a smaller luminous area such as 5mm 2, while meeting the processing needs, reducing energy waste as much as possible. The first optical element 200 can be made of H-K9L optical glass material, which can process visible light and near-infrared regions; the first optical element 200 can be a square cylindrical mirror with a thick center and a thin edge, and its center thickness can be about 3mm, which is used to adjust the divergence angle of the light beam 1 incident therein on the fast axis and the slow axis of the first optical element 200, and keep the two consistent, so as to avoid excessive divergence of the surface light source 100 on the slow axis and cause light loss, at least increase the light flux at the first optical element 200. The second optical element 300 can be made of H-K9L optical glass material, which can process visible light and near-infrared regions; the second optical element 300 can be a cylindrical lens with a thick center and a thin edge, and its center thickness can be about 6mm, which is used to adjust the collimation of the light beam 1 with a moderate divergence angle, so that the light beam 1 can propagate according to the preset optical path, and improve the light supply accuracy and reliability of the lens assembly. The third optical element 400 can be made of H-K9L optical glass material, which can process visible light and near-infrared regions; the third optical element 400 can be a cylindrical lens with a thick center and thin edges, and its center thickness can be about 6 mm, which is used to focus the light beam 1, reduce the size of the collimated light beam 1, and form a target light spot for operation, so as to facilitate subsequent operations such as marking, drilling, welding or cutting of the product, thereby improving the processing effect.

[0034] At the same time, this example optimizes the light emitting area size of the surface light source 100 and sets it to 5mm 2 ~30mm 2 Within this range, it is possible to avoid the light-emitting area of ​​the surface light source 100 being too small, which would result in the total amount of light in the entire lens assembly being too small and the optical power being unable to meet the processing requirements; it is also possible to avoid the light-emitting area of ​​the surface light source 100 being too large, which would result in the divergence angle of the light beam 1 being too large and the need to add additional optical elements to improve the focusing effect, which would make the structure of the entire lens assembly bulky and complex, and not conducive to subsequent re-assignment.

[0035] It should be explained that a point light source refers to a point-shaped light-emitting surface, and a surface light source 100 refers to a light-emitting surface (non-point-shaped) with a certain size. The line where the fast axis of the first optical element 200 is located is parallel to the line where the axial direction of the first optical element 200 is located, and the line where the slow axis of the first optical element 200 is located is perpendicular to the line where the fast axis of the first optical element 200 is located.

[0036] In a possible implementation, the light output angle of the surface light source 100 is less than or equal to 5°; and / or, the wavelength of the light of the surface light source 100 is 400nm to 500nm. Such an arrangement can avoid energy waste caused by an excessively large light output angle, and make the divergence angle and wavelength of the initial light beam 1 emitted from the surface light source 100 moderate, ensuring that the initial light beam 1 can completely fall into the first optical element, and obtain a nearly conical target light beam 1 by adjusting the divergence angle on its fast axis and slow axis through the first optical element 200, thereby improving the effective utilization rate of the surface light source 100 and reducing light loss. For example, but not limited to, the light output angle of the light beam 1 emitted by the surface light source 100 is 3.2°, and the wavelength of the light of the surface light source 100 is 450nm.

[0037] In a possible implementation, the first optical element 200 is a cylindrical mirror. This arrangement can ensure that the divergence angles of the light beam 1 passing through the first optical element 200 on its fast axis and slow axis are consistent, thereby ensuring the accuracy and quality of laser operation.

[0038] In a possible implementation, the focal length of the first optical element 200 is -400mm to -300mm; and / or, the focal length of the second optical element 300 is 50mm to 70mm; and / or, the focal length of the third optical element 400 is 45mm to 65mm. Such an arrangement can make the surface light source 100 and the first optical element 200, the second optical element 300 and the third optical element 400 cooperate compactly and closely, shorten the overall length of the lens assembly, and realize the miniaturized layout of the lens assembly. For example, the focal length of the first optical element 200 is -358 mm, the radius of curvature of the curved surface of the first optical element 200 facing the surface light source 100 is -188.16 mm, and the radius of curvature of the curved surface of the first optical element 200 facing the second optical element 300 is infinite; the focal length of the second optical element 300 is 59.4 mm, the radius of curvature of the curved surface of the second optical element 300 facing the first optical element 200 is 45.191 mm, and the radius of curvature of the curved surface of the second optical element 300 facing the third optical element 400 is -95.957 mm; the focal length of the third optical element 400 is 54.6 mm, the radius of curvature of the curved surface of the third optical element 400 facing the second optical element 300 is 59.391 mm, and the radius of curvature of the curved surface of the third optical element 400 facing away from the second optical element 300 is -53.443 mm.

[0039] In a possible implementation, the spot area of ​​the lens assembly at the focus is 0.45 mm 2 ~0.55mm 2 Such a configuration can enable the lens assembly to provide a beam size that meets the processing requirements and improve the laser processing effect. For example, but not limited to, the spot area of ​​the lens assembly at its focus is 0.5mm2 .

[0040] In a possible implementation manner, a fourth optical element 500 is further included. The fourth optical element 500 is disposed between the surface light source 100 and the first optical element 200 . The fourth optical element 500 is used to enlarge the radiation area of ​​the light beam 1 .

[0041] In this embodiment, the specific configuration of the lens assembly is further optimized. Specifically, the lens assembly is configured as a composite component including at least a surface light source 100, a first optical element 200, a second optical element 300, a third optical element 400, and a fourth optical element 500. The fourth optical element 500 can be made of H-K9L optical glass material, which can process visible light and near-infrared regions; the fourth optical element 500 can be a cylindrical lens with a thick center and a thin edge, and its center thickness can be about 3 mm, which is used to enlarge the radiation area of ​​the light beam 1 emitted by the surface light source 100, improve the light propagation effect, and facilitate the subsequent first optical element 200 to shape the fast and slow axes of the light beam 1 and adjust the optical fiber collimation.

[0042] In a possible implementation, the first optical element 200 is used to perform fast and slow axis shaping and fiber collimation adjustment on the light beam 1 magnified by the fourth optical element 500. In this example, the first optical element 200 is configured as a cylindrical mirror so that the divergence angles of the light beam emitted from the fourth optical element 500 on its fast axis and slow axis are consistent, so as to avoid the situation where the light emitted from the fourth optical element 500 cannot fall on the second optical element 300 due to too large a divergence angle, or the light emitted from the fourth optical element 500 is too low to meet the light processing requirements due to too small a divergence angle. At the same time, the cylindrical mirror can also be used to collimate the light emitted from the fourth optical element 500 so that the light emitted from the lens assembly falls into the designated processing area, thereby improving the processing accuracy.

[0043] In a possible implementation, the focal length of the fourth optical element 500 is -30 mm to -10 mm. This arrangement can make the surface light source 100 and the fourth optical element 500, the first optical element 200, the second optical element 300 and the third optical element 400 cooperate compactly and closely, shorten the overall length of the lens assembly, and achieve a miniaturized layout of the lens assembly. For example, but not limited to, the focal length of the fourth optical element 500 is -20 mm, the curvature radius of the curved surface of the fourth optical element 500 facing the surface light source 100 is -23.921 mm, and the curvature radius of the curved surface of the fourth optical element 500 facing the first optical element 200 is 20.767 mm.

[0044] In a possible implementation manner, the distance between the fourth optical element 500 and the surface light source 100 is 12 mm to 18 mm; and / or the distance between the first optical element 200 and the fourth optical element 500 is

[0045] 5mm~9mm; and / or, the distance between the second optical element 300 and the first optical element 200 is 16.6mm~26.6mm; and / or, the distance between the third optical element 400 and the second optical element 300 is 6mm~12mm. Such arrangement can make the cooperation between the surface light source 100 and the fourth optical element 500, the first optical element 200, the second optical element 300 and the third optical element 400 compact and close, shorten the overall length of the lens assembly, and realize the miniaturized layout of the lens assembly. For example, the distance between the fourth optical element 500 and the surface light source 100 is 15mm, the distance between the first optical element 200 and the fourth optical element 500 is 7mm, the distance between the second optical element 300 and the first optical element 200 is 21.6mm, and the distance between the third optical element 400 and the second optical element 300 is 9mm. The total length of the lens assembly provided in this example can be controlled within 56mm, and the working distance is controlled above 60mm, which meets the laser processing of workpieces with a surface height difference of less than 60mm.

[0046] In addition, if Figure 2 As shown, the present application also provides a laser device, which includes a housing 10 and the lens assembly as described above, the housing 10 having an emitting end 11 and a light emitting end 12 that are relatively arranged, the lens assembly is arranged in the housing 10, the surface light source 100 of the lens assembly is located at the emitting end 11, and the third optical element 400 of the lens assembly is located at the light emitting end 12.

[0047] In this embodiment, a laser device using a surface light source 100 is provided. The laser device is configured as a combined component including at least a housing 10 and a lens assembly. The housing 10 may be an aluminum alloy cylindrical housing having a containing chamber. The lens assembly is arranged in the containing chamber and may be fixed at a designated position inside the housing 10 by structures such as a support plate and a buckle to prevent the lens assembly from shaking and affecting the laser processing effect. The left and right circular sides respectively form an emitting end 11 and a light emitting end 12. The surface light source 100 of the lens assembly may be arranged near the emitting end 11 to emit a light beam 1. The fourth optical element 500, the first optical element 200, the second optical element 300 and the third optical element 400 of the lens assembly are arranged in sequence along the direction from the emitting end 11 to the light emitting end 12, and the light emitting end 12 is located near the focus of the lens assembly (for example, the light emitting end 12 may be between the front focal depth and the rear focal depth) to output a light beam 1 with a moderate spot size to achieve laser processing. The laser device provided in this example has a simple structure, a compact layout, is easy to assemble, and has a good laser processing effect.

[0048] In addition, the specific structure of the lens assembly refers to the above-mentioned embodiments. Since the laser device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0049] In a possible implementation manner, a cooling assembly 20 is further included, and the cooling assembly 20 is disposed around the shell 10 .

[0050] In this embodiment, the specific configuration of the laser device is further optimized. Specifically, the laser device is configured as a combination component including at least a housing 10, a lens assembly and a cooling assembly 20. The cooling assembly 20 can be configured as a combination component including at least a coil 21, a water inlet pipe 22, a water outlet pipe 23 and a cold source 24. The coil 21 can be spirally arranged on the periphery of the housing 10 along the axial direction of the housing 10. The two ends of the coil 21 are respectively connected to the water inlet pipe 22 and the water outlet pipe 23. The water inlet pipe 22 is connected to the cold source 24, and the water outlet pipe 23 is connected to the recovery tank. In this way, the coolant in the cold source 24 tank can be transported to the housing 10 to dissipate heat and cool the lens assembly, thereby increasing the optical power of the laser device and improving the processing effect. In this example, the coolant can be cooling water or a refrigerant, and the specific working medium of the coolant is not limited here.

[0051] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0052] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0053] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A lens assembly, characterized in that: The invention comprises a surface light source (100), a first optical element (200), a second optical element (300) and a third optical element (400) which are arranged in sequence and at intervals, wherein the light emitting area of ​​the surface light source (100) is 5 mm 2 ~30mm 2 The surface light source (100) is used to emit a light beam (1); the first optical element (200) is used to adjust the divergence angle of the light beam (1); the second optical element (300) is used to adjust the collimation of the light beam (1); and the third optical element (400) is used to focus the light beam (1).

2. The lens assembly according to claim 1, characterized in that: The light emission angle of the surface light source (100) is less than or equal to 5°; and / or, The light wavelength of the surface light source (100) is 400nm-500nm.

3. The lens assembly according to claim 1, characterized in that: The focal length of the first optical element (200) is -400 mm to -300 mm.

4. The lens assembly according to claim 1, characterized in that: The focal length of the second optical element (300) is 50 mm to 70 mm; and / or, The focal length of the third optical element (400) is 45 mm to 65 mm; and / or, The spot area of ​​the lens assembly at the focus is 0.45mm 2 ~0.55mm 2 .

5. The lens assembly according to claim 1, characterized in that: It also comprises a fourth optical element (500), wherein the fourth optical element (500) is arranged between the surface light source (100) and the first optical element (200), and the fourth optical element (500) is used to enlarge the radiation area of ​​the light beam (1).

6. The lens assembly according to claim 5, characterized in that: The first optical element (200) is used to perform fast and slow axis shaping and optical fiber collimation adjustment on the light beam (1) amplified by the fourth optical element (500).

7. The lens assembly according to claim 5, characterized in that: The focal length of the fourth optical element (500) is -30 mm to -10 mm.

8. The lens assembly according to claim 7, characterized in that: The distance between the fourth optical element (500) and the surface light source (100) is 12 mm to 18 mm; and / or, The distance between the first optical element (200) and the fourth optical element (500) is 5 mm to 9 mm; and / or, The distance between the second optical element (300) and the first optical element (200) is 16.6 mm to 26.6 mm; and / or, The distance between the third optical element (400) and the second optical element (300) is 6 mm to 12 mm.

9. A laser device, characterized in that: The invention comprises a housing (10) and a lens assembly as claimed in any one of claims 1 to 8, wherein the housing (10) has an emitting end (11) and a light emitting end (12) which are arranged opposite to each other, the lens assembly is arranged in the housing (10), a surface light source (100) of the lens assembly is located at the emitting end (11), and a third optical element (400) of the lens assembly is located at the light emitting end (12).

10. The laser device according to claim 9, characterized in that It also includes a cooling component (20), wherein the cooling component (20) is disposed around the shell (10).

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