Variable-focus F-Sin theta lens and laser processing equipment

Abstract

The invention discloses a variable-focus F-Sin theta lens and laser processing equipment, and relates to the technical field of optical equipment. The variable-focus F-Sin theta lens comprises a first lens group, a second lens group and a third lens group which are sequentially arranged from the object side to the image side, each lens group comprises at least one lens, and the distances among the first lens group, the second lens group and the third lens group are adjustable, so that the focal length of the variable-focus F-Sin theta lens can be adjusted within an effective zoom range. The variable-focus F-Sin theta lens provided by the invention has relatively good field flattening performance in an effective zoom range. When the variable-focus F-Sin theta lens is applied to multi-beam laser processing based on diffractive optical element beam splitting, high-precision and equal-interval light spot distribution can be achieved. Moreover, the focal length of the variable-focus F-Sin theta lens is adjusted within an effective zooming range, so that the requirements of different light spot distances and different image plane sizes during precise multi-beam processing are met.

Description

Technical Field

[0001] The present application relates to the technical field of optical equipment, and in particular to a variable-focus F-Sinθ lens and laser processing equipment. Background Art

[0002] In the field of multi-beam laser processing, galvanometers / polyhedron mirrors are often used in conjunction with conventional focusing lenses, specialized f-θ lenses, or even more specialized f-sin θ lenses. In these processing methods, conventional focusing lenses lack field flatness, resulting in a curved focal plane and poor precision, making them difficult to meet the requirements of precision multi-beam processing. When specialized f-θ lenses are used as focusing lenses, under paraxial conditions (i.e., low beam order and small incident angle θ), the focal plane exhibits relatively good field flatness, and the change in image height with increasing θ values can be approximately linear (i.e., the spacing between adjacent focused spots remains approximately the same). However, as the beam order increases and the incident angle θ gradually increases, the angle between the beam and the optical axis no longer meets the paraxial condition. As the beam order increases, the nonlinear relationship between order and image height becomes increasingly pronounced, leading to increasing deviations in the spacing between adjacent focused spots, which no longer meet the requirements of precision processing. To improve this problem, the related technology uses F-sinθ lenses, which can always maintain a good linear relationship between the beam order and the imaging height. However, this type of lens is fixed-focus and cannot meet the requirements of flexible and changeable spot spacing and image size during precision multi-beam processing. Summary of the Invention

[0003] The purpose of this application includes providing a variable focus F-Sinθ lens and laser processing equipment, which can adjust the focal length to meet the requirements of different spot spacing and different image plane sizes during precision multi-beam processing.

[0004] The embodiments of the present application can be implemented as follows: In a first aspect, the present application provides a variable-focus F-Sinθ lens, which includes a first lens group, a second lens group, and a third lens group arranged in sequence from the object side to the image side, each lens group includes at least one lens, and the spacing between the first lens group, the second lens group, and the third lens group is adjustable so that the focal length of the variable-focus F-Sinθ lens can be adjusted within an effective zoom range. Within the effective zoom range, the imaging height of the variable-focus F-Sinθ lens remains proportional to the sine value of the incident angle of the incident light beam.

[0005] In an optional embodiment, the effective zoom range of the variable-focus F-Sinθ lens is 75 mm to 125 mm.

[0006] In an optional embodiment, the number of lenses of the variable-focus F-Sinθ lens is five, the first lens group includes a first lens and a second lens, the second lens group includes a third lens and a fourth lens, the third lens group includes a fifth lens, and the first lens, the second lens, the third lens, the fourth lens and the fifth lens are arranged in sequence along the optical axis.

[0007] In an optional embodiment, the first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has negative optical power, and the fifth lens has positive optical power.

[0008] In an optional embodiment, the optical power of the first lens is -15~-25 μm -1 , the focal length of the second lens is 5~8m -1 The focal length of the third lens is 5~8 m -1 The focal length of the fourth lens is -1~-2.5 m -1 The optical power of the fifth lens is 3~6 m -1 .

[0009] In an optional embodiment, the Abbe number of the first lens is 20-30, the Abbe number of the second lens is 60-70, the Abbe number of the third lens is 20-30, the Abbe number of the fourth lens is 20-30, and the Abbe number of the fifth lens is 60-70.

[0010] In an optional embodiment, the first lens, the second lens, and the fourth lens are meniscus lenses, and the third lens and the fifth lens are biconvex lenses.

[0011] In an optional embodiment, the radius of curvature of the object side surface of the first lens is -9 to -11 mm, and the radius of curvature of the image side surface is -12 to -15 mm; The curvature radius of the object side of the second lens is -90~-110 mm, and the curvature radius of the image side is -40~-50 mm; The object side of the third lens has a curvature radius of 200 to 220 mm, and the image side has a curvature radius of -240 to -260 mm. The object-side surface of the fourth lens has a curvature radius of 60 to 70 mm, and the image-side surface has a curvature radius of 50 to 60 mm. The object-side surface of the fifth lens has a curvature radius of 800 to 1000 mm, and the image-side surface has a curvature radius of -120 to -150 mm.

[0012] In the second aspect, the present application provides a laser processing device, comprising a light source, a beam splitting device and a variable-focus F-Sinθ lens of any one of the aforementioned embodiments, the light source, the beam splitting device and the variable-focus F-Sinθ lens are arranged in sequence, the light source is used to emit an initial light beam, and the beam splitting device is used to split the initial light beam into multiple sub-beams, and the multiple sub-beams can pass through the variable-focus F-Sinθ lens.

[0013] In an alternative embodiment, the beam splitting device comprises a diffractive optical element.

[0014] In an optional embodiment, the multiple sub-beams are parallel to each other after being emitted from the variable-focus F-Sinθ lens.

[0015] In an optional embodiment, after the multiple sub-beams are emitted from the variable-focus F-Sinθ lens, the spacing between adjacent sub-beams is 2-5 mm.

[0016] The advantageous effects of the variable-focus F-Sinθ lens and laser processing equipment provided by the embodiments of the present application include: The variable-focus F-Sinθ lens provided herein includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side. Each lens group includes at least one lens. The spacing between the first, second, and third lens groups is adjustable, allowing the focal length of the variable-focus F-Sinθ lens to be adjusted within the effective zoom range. Within the effective zoom range, the image height of the variable-focus F-Sinθ lens remains proportional to the sine of the incident angle of the incident light beam. The variable-focus F-Sinθ lens provided herein exhibits excellent field flatness, meaning that beams of light emitted from the same object plane at different incident angles converge to convergently distributed points after passing through the lens. Compared to conventional focusing lenses (F-tanθ lenses) and field-flattening lenses (F-θ lenses), the lens introduces appropriate barrel distortion (negative distortion), thereby correcting distortion across the entire field of view within the zoom range. When applied to multi-beam laser processing using diffractive optical elements (DOEs), the variable-focus F-Sinθ lens achieves a high-precision, uniformly spaced spot distribution. Furthermore, by adjusting the focal length within the effective zoom range, the variable-focus F-Sinθ lens can adjust the spot spacing and image size, thus meeting the varying spot spacing and image size requirements of precision multi-beam processing.

[0017] The laser processing equipment provided in embodiments of the present application includes a light source, a beam splitting device, and the aforementioned variable-focus F-Sinθ lens. The beam splitting device can split the light beam emitted by the light source into multiple sub-beams. After passing through the variable-focus F-Sinθ lens, the multiple sub-beams form evenly spaced parallel beams for processing. Furthermore, by adjusting the focal length of the variable-focus F-Sinθ lens, different processing requirements can be met, and the need for lens replacement can be reduced, thereby improving processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 Schematic diagram of multi-beam laser processing; Figure 2 This is a first schematic diagram (short focus state) of a beam splitting device and a variable focus F-Sinθ lens in an embodiment of the present application; Figure 3 This is a second schematic diagram (mid-focus state) of a beam splitting device and a variable-focus F-Sinθ lens in one embodiment of the present application; Figure 4 This is a third schematic diagram (telephoto state) of a beam splitting device and a variable-focus F-Sinθ lens in an embodiment of the present application.

[0020] Icon: 10-lens; 100-variable focus F-Sinθ lens; 110-first lens; 120-second lens; 130-third lens; 140-fourth lens; 150-fifth lens; 200-beam splitter. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0024] In the description of this application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the invented product is usually placed when in use. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on this application.

[0025] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0026] It should be noted that, in the absence of conflict, the features in the embodiments of this application can be combined with each other.

[0027] Figure 1 This is a schematic diagram of multi-beam laser processing. Figure 1As shown, in the field of multi-beam laser processing technology based on diffractive optical element beam splitting, a single laser beam emitted by a light source (not shown) is split into multiple sub-beams using a beam splitting device 200 (diffractive optical element). These sub-beams, after passing through a lens 10, form multiple parallel and spaced beams for processing. In the prior art, when using an F-tanθ lens for processing, the plane formed by the focal spots of each sub-beam is an arc-shaped surface. The spot sizes and spacings formed on the processed surface are unequal, and the processing effect cannot meet high-precision requirements. Furthermore, when using an F-θ lens for processing, as the order m of the diffracted beam gradually increases, the nonlinear relationship between the m value and the imaging height no longer holds. This results in a gradually increasing spacing between adjacent spots farther from the image center (or farther from the optical axis), leading to increasingly significant errors. The processing effect exhibits poorer precision the further away from the image center, making it increasingly difficult to meet high-precision requirements. The related art uses an F-Sinθ lens in conjunction with a beam splitter 200, taking advantage of the f-sinθ lens's excellent field flatness and the proportional relationship between the imaging height and the sine of the incident beam's angle of incidence, thereby achieving a high-precision, equally spaced spot distribution. However, the F-Sinθ lens used in the related art is a fixed-focus lens, and the spot spacing and image plane size cannot be adjusted. When the spacing between adjacent spots on the processed surface (or the imaging range / accuracy of the processed surface) needs to be adjusted, the system is limited to replacing F-Sinθ lenses with different focal lengths. In actual system design and processing, this leads to complex structural design, inconvenient lens replacement during use, inability to flexibly meet various resolution requirements, and excessive cost.

[0028] In order to improve the problems in the above-mentioned related technologies, the embodiment of the present application provides a variable-focus F-Sinθ lens 100 and laser processing equipment, which can achieve high-precision, equally spaced spot distribution, and can also adjust the focal length to meet different processing requirements and improve processing efficiency.

[0029] Figure 2 This is a first schematic diagram (short focus state) of the beam splitting device 200 and the variable focus F-Sinθ lens 100 in one embodiment of the present application. Figure 2 As shown, the laser processing equipment provided in an embodiment of the present application includes a light source (not shown), a beam splitter 200, and a variable-focus F-Sinθ lens 100. The light source, beam splitter 200, and variable-focus F-Sinθ lens 100 are arranged in sequence. The light source is used to emit an initial light beam, and the beam splitter 200 is used to split the initial light beam into multiple sub-beams. The multiple sub-beams can pass through the variable-focus F-Sinθ lens 100 and converge into a light spot. In this embodiment, the multiple sub-beams are parallel to each other after being emitted from the variable-focus F-Sinθ lens 100, and the light spots formed on the image plane are uniformly spaced.

[0030] In this embodiment, the light source is a laser light source; the light source may be a single wavelength light source or a combination of different wavelengths.

[0031] In this embodiment, the beam splitting device 200 includes a diffractive optical element (DOE). Based on diffraction theory, a DOE can split an incoming initial beam into multiple sub-beams through a precisely designed diffraction pattern. Each sub-beam can have the same intensity or a different intensity distribution while maintaining a high degree of directional control. When used in laser processing, this can achieve uniform energy distribution or multi-point simultaneous processing. In other embodiments, other devices with beam splitting capabilities can also be used to split the initial beam into multiple sub-beams.

[0032] The initial beam is split by the diffractive optical element to form multiple laser beams. The diffraction equation is Ʌ·sinθ=m·λ. Where Ʌ is the grating constant; θ is the incident angle of the emitted sub-beam, that is, the angle with the optical axis or the initial beam; m is the diffracted beam order, which can be 0, ±1, ±2... Please refer to Figure 1 When the diffraction beam order m=1, the incident angle is θ1; when the diffraction beam order m=2, the incident angle is θ2; when the diffraction beam order m=3, the incident angle is θ3. λ is the wavelength of the light beam. In actual use, a laser with good monochromaticity can be used as a light source, so the wavelength λ can be regarded as a constant. At the same time, once the design and processing of the diffraction optical element are completed, its grating constant Ʌ is also a fixed value. It can be seen from the above formula that the sinθ value is linearly related to the m value. At the same time, in order to meet the use requirements, the spot height ρ (equivalent to the imaging height) corresponding to each order of the diffraction beam on the image plane should satisfy ρ=F·sinθ. Compared with traditional focusing lenses (F-tanθ lenses) and flat-field lenses (F-θ lenses), the variable focus F-Sinθ lens 100 of the embodiment of the present application introduces appropriate barrel distortion, thereby correcting the distortion of the entire field of view within the effective zoom range. This application utilizes this characteristic of the F-Sinθ lens to achieve a proportional relationship between the imaging height and the sine value of the incident light beam angle θ, thereby achieving a high-precision, equally spaced spot distribution that can meet the needs of precision multi-beam processing.

[0033] In this embodiment, after the multiple sub-beams are emitted from the variable-focus F-Sinθ lens 100, the spacing between adjacent sub-beams is 2-5 mm. That is, the spacing between adjacent spots formed by the multiple sub-beams on the image plane is 2-5 mm. The spacing between adjacent spots can be adjusted by adjusting the focal length of the variable-focus F-Sinθ lens 100.

[0034] In the embodiment of the present application, the variable-focus F-Sinθ lens 100 includes a first lens group, a second lens group, and a third lens group, arranged sequentially from the object side to the image side (from left to right in the figure). Each lens group includes at least one lens. The spacing between the first lens group, the second lens group, and the third lens group is adjustable to enable the focal length of the variable-focus F-Sinθ lens 100 to be adjusted within the effective zoom range. Within the effective zoom range, the image height of the variable-focus F-Sinθ lens 100 remains proportional to the sine of the incident angle of the incident light beam.

[0035] Figure 3 This is a second schematic diagram (mid-focus state) of the beam splitting device 200 and the variable-focus F-Sinθ lens 100 in one embodiment of the present application; Figure 4 This is a third schematic diagram (telephoto state) of the beam splitting device 200 and the variable-focus F-Sinθ lens 100 in one embodiment of the present application. Figures 2 to 4 Schematic diagrams of imaging by the variable focus F-Sinθ lens 100 in short focus, medium focus, and long focus states, respectively. It can be seen that by adjusting the distances between the first lens group, the second lens group, and the third lens group, the focal length of the lens can be adjusted.

[0036] Optionally, the effective zoom range of the variable-focus F-Sinθ lens 100 is 75 mm to 125 mm.

[0037] like Figures 2 to 4 As shown, in this embodiment, the variable-focus F-Sinθ lens 100 includes five lenses. The first lens group includes a first lens 110 and a second lens 120, the second lens group includes a third lens 130 and a fourth lens 140, and the third lens group includes a fifth lens 150. The first lens 110, the second lens 120, the third lens 130, the fourth lens 140 and the fifth lens 150 are arranged in sequence along the optical axis.

[0038] Optionally, the first lens 110 has negative optical power, the second lens 120 has positive optical power, the third lens 130 has positive optical power, the fourth lens 140 has negative optical power, and the fifth lens 150 has positive optical power.

[0039] Optionally, the optical power of the first lens 110 is -15 to -25 μm. -1 The optical power of the second lens 120 is 5~8 m -1 The focal length of the third lens 130 is 5~8 μm. -1 The optical power of the fourth lens 140 is -1~-2.5 m -1 The optical power of the fifth lens 150 is 3~6 m -1By controlling the focal power of each lens, we can effectively ensure that the image height remains proportional to the sine of the incident beam's angle of incidence, θ, within the effective zoom range. This results in a high-precision, equally spaced spot distribution, meeting the requirements of precision multi-beam processing. It should be understood that the focal power is the reciprocal of the focal length.

[0040] In a specific embodiment, the optical power of the first lens 110 is -20.993 m -1 The optical power of the second lens 120 is 6.772 m -1 The focal length of the third lens 130 is 6.902 m -1 The focal power of the fourth lens 140 is -1.848 m -1 The optical power of the fifth lens 150 is 4.350 m -1 .

[0041] Optionally, the Abbe number of the first lens is 20-30, the Abbe number of the second lens is 60-70, the Abbe number of the third lens is 20-30, the Abbe number of the fourth lens is 20-30, and the Abbe number of the fifth lens is 60-70.

[0042] In a specific embodiment, the Abbe number of the first lens 110 is 25.7566, the Abbe number of the second lens 120 is 64.1673, the Abbe number of the third lens 130 is 25.7566, the Abbe number of the fourth lens 140 is 25.7566, and the Abbe number of the fifth lens 150 is 64.1673.

[0043] Furthermore, the first lens 110, the second lens 120, and the fourth lens 140 are meniscus lenses, and the third lens 130 and the fifth lens 150 are biconvex lenses. Optionally, the radius of curvature of the object side surface of the first lens is -9 to -11 mm, and the radius of curvature of the image side surface is -12 to -15 mm; the radius of curvature of the object side surface of the second lens is -90 to -110 mm, and the radius of curvature of the image side surface is -40 to -50 mm; the radius of curvature of the object side surface of the third lens is 200 to 220 mm, and the radius of curvature of the image side surface is -240 to -260 mm; the radius of curvature of the object side surface of the fourth lens is 60 to 70 mm, and the radius of curvature of the image side surface is 50 to 60 mm; and the radius of curvature of the object side surface of the fifth lens is 800 to 1000 mm, and the radius of curvature of the image side surface is -120 to -150 mm.

[0044] In a specific embodiment, the radius of curvature of the object-side surface of the first lens 110 is -9.826 mm, and the radius of curvature of the image-side surface is -13.329 mm; The object-side surface of the second lens 120 has a curvature radius of -104.022 mm, and the image-side surface has a curvature radius of -44.021 mm. The object-side surface of the third lens 130 has a curvature radius of 206.228 mm, and the image-side surface has a curvature radius of -253.425 mm. The object-side surface of the fourth lens 140 has a curvature radius of 64.004 mm, and the image-side surface has a curvature radius of 55.620 mm. The object-side surface of the fifth lens 150 has a curvature radius of 924.006 mm, and the image-side surface has a curvature radius of -136.33 mm.

[0045] It should be understood that when the center of curvature of the lens surface is on the object side of the surface ( Figure 2 On the left side of the lens surface), its radius of curvature is negative; on the contrary, when the center of curvature of the lens surface is on the image side of the surface ( Figure 2 By carefully selecting the surface shapes and specific curvature radii of each lens, the variable-focus F-Sinθ lens 100 maintains a highly proportional relationship between the image height and the sine of the incident light beam's angle of incidence, θ, within an effective zoom range of 75mm to 125mm. This ensures the "F-Sinθ" property.

[0046] In this embodiment, when the variable focus F-Sinθ lens 100 is in the short focus state (eg Figure 2 ), the interval between the first lens 110 and the second lens 120 is 11.134 mm, the interval between the second lens 120 and the third lens 130 is 38.207 mm, the interval between the third lens 130 and the fourth lens 140 is 0 mm, and the interval between the fourth lens 140 and the fifth lens 150 is 22.168 mm. At this time, the spacing between the light spots is 2.344 mm; when the variable focus F-Sinθ lens 100 is in the mid-focus state (such as Figure 3 ), the interval between the first lens 110 and the second lens 120 is 9.488 mm, the interval between the second lens 120 and the third lens 130 is 8.290 mm, the interval between the third lens 130 and the fourth lens 140 is 1.896 mm, and the interval between the fourth lens 140 and the fifth lens 150 is 100.657 mm. At this time, the spacing between the light spots is 3.125 mm. When the variable focus F-Sinθ lens 100 is in the telephoto state (such as Figure 4 ), the interval between the first lens 110 and the second lens 120 is 0 mm, the interval between the second lens 120 and the third lens 130 is 0 mm, the interval between the third lens 130 and the fourth lens 140 is 1.908 mm, and the interval between the fourth lens 140 and the fifth lens 150 is 132.544 mm. At this time, the spacing between the light spots is 3.906 mm.

[0047] In summary, embodiments of the present application provide a variable-focus F-Sinθ lens 100 and laser processing equipment. The variable-focus F-Sinθ lens 100 includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side. Each lens group includes at least one lens. The spacing between the first lens group, the second lens group, and the third lens group is adjustable so that the focal length of the variable-focus F-Sinθ lens 100 can be adjusted within an effective zoom range. Within the effective zoom range, the image height of the variable-focus F-Sinθ lens 100 remains proportional to the sine of the incident angle of the incident light beam. Within the effective zoom range, the image height of the variable-focus F-Sinθ lens 100 of the present application remains proportional to the sine of the incident angle of the incident light beam, and has excellent flat field properties. That is, after light beams of different incident angles emitted from the same object plane pass through the variable-focus F-Sinθ lens 100, the focused points tend to be distributed on the same plane. Compared to traditional focusing lenses (F-tanθ lenses) and field-flattening lenses (F-θ lenses), the variable-focus F-Sinθ lens 100 introduces appropriate barrel distortion (negative distortion), thereby correcting the distortion across the entire field of view within the zoom range. When the variable-focus F-Sinθ lens 100 is applied to multi-beam laser processing based on beam splitting using a diffractive optical element, it can achieve a high-precision, equally spaced spot distribution. Furthermore, the variable-focus F-Sinθ lens 100 can adjust the spot spacing and image size by adjusting the focal length within the effective zoom range, thereby meeting the requirements for different spot spacings and image sizes during precision multi-beam processing. The laser processing equipment provided in an embodiment of the present application includes a light source, a beam splitting device 200, and the variable-focus F-Sinθ lens 100 described above. The beam splitting device 200 can split the light beam emitted by the light source into multiple sub-beams. After passing through the variable-focus F-Sinθ lens 100, the multiple sub-beams can form evenly spaced parallel light for processing. Furthermore, by adjusting the focal length of the variable-focus F-Sinθ lens 100 , different processing requirements can be met; and the operation of replacing lenses can be reduced, thereby improving processing efficiency.

[0048] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. A variable focus F-Sinθ lens, characterized in that: The variable-focus F-Sinθ lens includes a first lens group, a second lens group, and a third lens group arranged in sequence from the object side to the image side. Each of the lens groups includes at least one lens. The spacing between the first lens group, the second lens group, and the third lens group is adjustable so that the focal length of the variable-focus F-Sinθ lens can be adjusted within an effective zoom range. Within the effective zoom range, the imaging height of the variable-focus F-Sinθ lens remains proportional to the sine value of the incident angle of the incident light beam.

2. The variable focus F-Sinθ lens according to claim 1, wherein: The effective zoom range of the variable-focus F-Sinθ lens is 75mm to 125mm.

3. The variable focus F-Sinθ lens according to claim 1, wherein: The variable-focus F-Sinθ lens has five lenses, the first lens group includes a first lens and a second lens, the second lens group includes a third lens and a fourth lens, the third lens group includes a fifth lens, and the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in sequence along the optical axis.

4. The variable focus F-Sinθ lens according to claim 3, wherein: The first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has negative optical power, and the fifth lens has positive optical power.

5. The variable focus F-Sinθ lens according to claim 4, wherein: The focal length of the first lens is -15~-25 μm -1 The focal length of the second lens is 5~8 m -1 The focal length of the third lens is 5~8 m -1 The focal length of the fourth lens is -1~-2.5 m -1 The optical power of the fifth lens is 3~6 m -1 .

6. The variable focus F-Sinθ lens according to claim 4, wherein: The Abbe number of the first lens is 20-30, the Abbe number of the second lens is 60-70, the Abbe number of the third lens is 20-30, the Abbe number of the fourth lens is 20-30, and the Abbe number of the fifth lens is 60-70.

7. The variable focus F-Sinθ lens according to claim 4, wherein: The first lens, the second lens, and the fourth lens are meniscus lenses, and the third lens and the fifth lens are biconvex lenses.

8. The variable focus F-Sinθ lens according to claim 4, wherein: The object-side surface of the first lens has a curvature radius of -9 to -11 mm, and the image-side surface has a curvature radius of -12 to -15 mm; The object-side surface of the second lens has a curvature radius of -90 to -110 mm, and the image-side surface has a curvature radius of -40 to -50 mm; The object-side surface of the third lens has a curvature radius of 200 to 220 mm, and the image-side surface has a curvature radius of -240 to -260 mm; The object-side surface of the fourth lens has a curvature radius of 60-70 mm, and the image-side surface has a curvature radius of 50-60 mm; The object-side surface of the fifth lens has a curvature radius of 800-1000 mm, and the image-side surface has a curvature radius of -120--150 mm.

9. A laser processing device, characterized in that: The invention comprises a light source, a beam splitting device and a variable-focus F-Sinθ lens according to any one of claims 1 to 8, wherein the light source, the beam splitting device and the variable-focus F-Sinθ lens are arranged in sequence, the light source is used to emit an initial light beam, the beam splitting device is used to split the initial light beam into a plurality of sub-beams, and the plurality of sub-beams can pass through the variable-focus F-Sinθ lens.

10. The laser processing equipment according to claim 9, characterized in that The beam splitting device comprises a diffractive optical element.

11. The laser processing equipment according to claim 9, characterized in that The plurality of sub-beams are parallel to each other after being emitted from the variable-focus F-Sinθ lens.

12. The laser processing equipment according to claim 11, characterized in that After the plurality of sub-beams are emitted from the variable-focus F-Sinθ lens, a distance between adjacent sub-beams is 2-5 mm.

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