Variable size line beam shaping device and method

Abstract

A variable size linear beam shaping device and shaping method, wherein the shaping device comprises a controller, an image collector, a laser, a collimating mirror, a spot scaling lens group, a beam splitter, a Powell lens, a cylindrical concave lens, and a cylindrical convex lens; the cylindrical concave lens and the cylindrical convex lens are respectively movably arranged; the beam splitter is used for splitting the linear beam into two Gaussian beams, one of which is transmitted to the Powell lens for beam shaping, and the other is transmitted to the image collector; the image collector is in signal connection with the controller, and the controller controls the cylindrical concave lens and the cylindrical convex lens to move to a target position according to the beam diameter collected by the image collector, and changes the major axis size and the minor axis size of the linear beam by adjusting the distance between the cylindrical concave lens and the cylindrical convex lens, so as to obtain a linear spot size meeting the requirements. The focal length between the cylindrical concave lens and the cylindrical convex lens is changed to obtain a spot size meeting the requirements, which has better adaptability.

Description

Technical Field

[0001] This invention relates to the field of laser annealing technology, specifically to a variable-size linear beam shaping device and method. Background Technology

[0002] Laser beam shaping is the process of redistributing the irradiance and phase of a laser beam. Depending on the application scenario and requirements, shaping a Gaussian-distributed laser beam into a flat-topped, uniformly distributed, or linear long beam can effectively improve the processing efficiency and quality of laser-based applications. In patent "PCT / US2020 / 013551," beams from multiple lasers are combined and superimposed to obtain a linear beam. However, due to overlap between beams, the uniformity of the final linear beam is reduced. To avoid beam overlap, patent "US2020 / 0235544 A1" uses a reflector to block overlapping portions of the output beam, thus obtaining a more uniform beam. However, due to beam obstruction, the utilization rate of laser energy is lower. Summary of the Invention

[0003] To address the issues of reduced uniformity and low laser energy utilization in beam shaping technology, this application provides a variable-size linear beam shaping device and method. By combining a Powell lens, a cylindrical concave lens, and a cylindrical convex lens, the beam shaping achieves high energy utilization, relatively uniform beam, and variable size.

[0004] The technical solution of this invention is as follows:

[0005] This invention provides a variable-size linear beam shaping device, including a controller and an image acquisition unit, and further including a laser, a collimating lens, a beam-scaling lens group, a beam splitter, a Powell lens, a cylindrical concave lens, and a cylindrical convex lens arranged sequentially along the main axis of the optical path;

[0006] The cylindrical concave lens and the cylindrical convex lens are respectively movable;

[0007] The beam splitter is used to split the linear beam into two Gaussian beams. One Gaussian beam is transmitted to the Powell lens for beam shaping, and the other Gaussian beam is transmitted to the image acquisition unit.

[0008] The image acquisition device is signal-connected to the controller. The controller controls the cylindrical concave lens and the cylindrical convex lens to move to the target position according to the beam diameter acquired by the image acquisition device. By adjusting the distance between the cylindrical concave lens and the cylindrical convex lens, the major axis and minor axis of the linear beam are changed to obtain the required linear spot size.

[0009] A further preferred embodiment includes a first rotating frame and a second rotating frame;

[0010] The cylindrical concave lens is disposed on the first rotating frame, and the cylindrical convex lens is disposed on the second rotating frame. The controller controls the first rotating frame and the second rotating frame to move so that the cylindrical concave lens and the cylindrical convex lens move to the target position.

[0011] A further preferred embodiment includes a convex lens disposed between the beam splitter and the image acquisition device, the convex lens being used to focus the Gaussian beam onto the image acquisition device.

[0012] More preferably, the image acquisition device acquires the beam diameter of the focused Gaussian beam, the controller calculates the beam diameter before beam splitting based on the beam diameter acquired by the image acquisition device, and controls the movement of the first rotating frame and the second rotating frame based on the beam diameter before beam splitting.

[0013] More preferably, the first rotating frame and the second rotating frame are respectively provided with a plurality of one-to-one corresponding mounting holes along the circumferential direction. The first rotating frame is used to mount cylindrical concave lenses with different focal lengths through the plurality of mounting holes, and the second rotating frame is used to mount cylindrical convex lenses with different focal lengths through the plurality of mounting holes.

[0014] More preferably, the controller controls the first and second rotating frames to rotate circumferentially according to the beam diameter of the Gaussian beam acquired by the image acquisition device, so as to select a cylindrical concave lens and a cylindrical convex lens that match the focal length.

[0015] More preferably, the light spot scaling lens group includes a plano-convex lens and a plano-concave lens, the size and focal length of which match the Powell lens.

[0016] More preferably, the incident light spot diameter of the Powell lens is 0.8 mm, and the minor axis dimension of the output beam of the Powell lens is equal to the incident light spot diameter.

[0017] More preferably, the beam splitter is a non-polarizing beam splitter, and the R:T ratio of the beam splitter is 10:90.

[0018] The present invention also provides a variable-size linear beam shaping method using the above-described variable-size linear beam shaping device, comprising the following steps:

[0019] Laser is generated by using a laser.

[0020] The laser beam is collimated using a collimating lens to obtain parallel light;

[0021] The parallel light is reduced to the required size by a beam-scaling lens group and split into two Gaussian beams by a beam splitter. One Gaussian beam is transmitted to the Powell lens and the other Gaussian beam is transmitted to the image acquisition unit.

[0022] Based on the beam diameter acquired by the image acquisition device, the cylindrical concave lens and cylindrical convex lens are controlled to move to the target position. By adjusting the distance between the cylindrical concave lens and cylindrical convex lens, the major axis and minor axis of the linear beam are changed to obtain the required linear spot size.

[0023] The variable-size linear beam shaping apparatus and shaping method according to the above embodiments have at least one of the following effects:

[0024] 1) In this invention, the collimating lens and the spot scaling lens group can be reasonably selected according to the different lasers and Powell lenses. The required spot size can be obtained by simply changing the focal length between the cylindrical concave lens and the cylindrical convex lens, which has better adaptability.

[0025] 2) In this invention, since multiple lenses are used to shape the beam, the shaping process is a refraction process. Compared with beam shaping by diffraction, this method can achieve higher energy utilization efficiency.

[0026] 3) In this invention, since the cylindrical concave lens and cylindrical convex lens can be selected and matched by rotating the rotatable frame, thereby obtaining linear beams of different sizes, it has better applicability. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the optical path of a variable-size linear beam shaping device;

[0028] Figure 2 This is a schematic diagram of a rotating eyeglass frame structure;

[0029] Figure 3 This is a flowchart of a variable-size linear beam shaping method. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0031] This embodiment provides a variable-size linear beam shaping device, the optical path schematic of which is shown below. Figure 1 As shown, it includes a controller 1 and an image acquisition unit 2, and also includes a laser 3, a collimating lens 4, a spot scaling lens group 5, a beam splitter 6, a Powell lens 7, a cylindrical concave lens 8, and a cylindrical convex lens 9 arranged sequentially along the main axis of the optical path.

[0032] In this system, laser 3 generates an initial laser beam, collimating lens 4 collimates the generated initial laser beam to obtain parallel light, beam-scaling lens group 5 reduces the incident parallel light to a suitable size, beam splitter splits the beam into two beams, one of which is transmitted to image acquisition device 2 for observation, and the other is transmitted to Powell lens 7 for beam shaping to obtain a linear beam with a longer major axis, according to the beam diameter acquired by image acquisition device 2. Controller 1 controls the cylindrical concave lens 8 and cylindrical convex lens 9 to move to the target position, and changes the major and minor axis dimensions of the linear beam by adjusting the distance between the cylindrical concave lens 8 and cylindrical convex lens 9 to obtain the required linear spot size. Specifically, the cylindrical concave lens 8 further lengthens the major axis dimension of the linear beam as needed, and the cylindrical convex lens 9 shortens the minor axis dimension of the linear beam as needed, thereby obtaining a smaller effective beam area and improving energy density.

[0033] The components are explained below.

[0034] Image acquisition device 2 is a standard industrial camera.

[0035] The Gaussian light spot output by laser 3 can be either a pulsed light signal or a continuous light signal, and the wavelength output by laser 3 is determined according to the requirements.

[0036] The beam scaling lens group 5 includes a plano-convex mirror and a plano-concave mirror. The size and focal length of the plano-convex and plano-concave mirrors are matched with the Powell lens. That is, the scaling factor of the beam scaling lens group 5 needs to be determined based on the actual output beam size of the laser 3 and the incident beam requirements of the Powell lens 7. Then, the size and focal length of the plano-convex and plano-concave mirrors are determined. For example, when the Powell lens 7 is determined, the beam scaling lens group 5 consists of a plano-convex mirror with a focal length of 200mm and a lens diameter of 25.4mm and a plano-concave mirror with a focal length of -50mm and a lens diameter of 25.4mm.

[0037] Beam splitter 6 is a non-polarizing beam splitter, wherein the ratio of reflected light to transmitted light of the beam splitter, R:T, is 10:90.

[0038] The incident beam diameter of the Powell lens 7 is 0.8 mm, and the minor axis of the output beam of the Powell lens 7 is equal to the incident beam diameter.

[0039] Furthermore, in order to realize the movement of the cylindrical concave lens and the cylindrical convex lens, this example also includes a first rotating frame and a second rotating frame. The cylindrical concave lens 8 is disposed on the first rotating frame, and the cylindrical convex lens 9 is disposed on the second rotating frame. The controller 1 controls the movement of the first rotating frame and the second rotating frame respectively so that the cylindrical concave lens 8 and the cylindrical convex lens 9 are moved to the target position. The first rotating frame and the second rotating frame have the same structure. The structure of the first rotating frame is described as an example.

[0040] like Figure 2 As shown, the first rotating frame includes a rotatable frame 100, a support column 200, and a support base 300. The rotatable frame 100 has a circular structure and multiple mounting holes 101 are provided along the circumference of the rotatable frame 100. Preferably, the mounting holes 101 have a square hole structure (rectangular hole). The first rotating frame mounts cylindrical concave lenses 8 with different focal lengths through the multiple mounting holes 101. Correspondingly, the rotatable frame of the second rotating frame also has one-to-one mounting holes along the circumference of the rotatable frame. The second rotating frame mounts cylindrical convex lenses 9 with different focal lengths through the multiple mounting holes.

[0041] For example, the first and second rotating frames each have four mounting holes, allowing the first rotating frame to mount four different cylindrical concave lenses 8 with different focal lengths, and the second rotating frame to mount four different cylindrical convex lenses 9 with different focal lengths. For instance, one example of cylindrical concave and cylindrical convex lenses that meet the required dimensions is: the cylindrical concave lens 8 has a length of 32mm, a width of 30mm, and a focal length of -150mm; the cylindrical convex lens 9 has a length of 32mm, a width of 30mm, and a focal length of 150mm.

[0042] Furthermore, it also includes a convex lens 10, which is disposed between the beam splitter 6 and the image acquisition unit 2. The convex lens 10 is used to focus the Gaussian beam onto the image acquisition unit 2. The image acquisition unit 2 acquires the beam diameter of the focused Gaussian beam. The controller 1 calculates the beam diameter before beam splitting based on the beam diameter of the image acquisition unit 2, and controls the movement of the first rotating frame and the second rotating frame based on the beam diameter before beam splitting.

[0043] For example, by using a standard industrial camera to read the size of the focused spot, the size of the spot before beam splitting can be calculated since the focal length of the convex lens 10 is known.

[0044] Furthermore, the controller 1 controls the first and second rotating frames to rotate circumferentially according to the beam diameter of the Gaussian beam acquired by the image acquisition device 2, so as to select the cylindrical concave lens 8 and cylindrical convex lens 9 that match the focal length, and automatically calculates the distance between the cylindrical concave lens 8 and the cylindrical convex lens 9, and controls the first and second rotating frames to move so that the cylindrical concave lens 8 and the cylindrical convex lens 9 move to the corresponding target positions, thereby obtaining the required linear light spot size.

[0045] In practical applications, motors can be installed at suitable positions on the rotatable frames of the first and second rotating eyeglass frames. Controller 1 controls the first and second rotating eyeglass frames to rotate in a circumferential direction by controlling the motors. Correspondingly, motors and casters can also be installed at suitable positions on the support bases of the first and second rotating eyeglass frames. Controller 1 controls the motors to drive the casters to control the automatic movement of the first and second rotating eyeglass frames. In addition, the first and second rotating eyeglass frames can also be moved manually.

[0046] The variable-size linear beam shaping device provided in this embodiment uses two rotatable frames to place cylindrical concave lenses and cylindrical convex lenses with different focal lengths, and the two rotatable frames can be rotated to select a suitable cylindrical lens to shape the beam. The device also changes the major axis and minor axis of the linear beam by adjusting the distance between the cylindrical concave lens and the cylindrical convex lens, thereby obtaining a linear beam size that meets the requirements.

[0047] Based on the variable-size linear beam shaping device provided in this embodiment, this embodiment also provides a variable-size linear beam shaping method using the device, the flowchart of which is shown below. Figure 3 As shown, the specific steps include the following.

[0048] S100: Generates laser light through a laser.

[0049] The Gaussian spot produced by the laser can be a pulsed light signal or a continuous light signal, and the wavelength of the laser output is determined according to the requirements.

[0050] S200: The laser is collimated using a collimating lens to obtain parallel light.

[0051] S300: The parallel light is reduced to the required size by the beam-scaling lens group and split into two Gaussian beams by the beam splitter. One Gaussian beam is transmitted to the Powell lens and the other Gaussian beam is transmitted to the image acquisition unit.

[0052] The beam scaling lens group consists of a plano-convex mirror and a plano-concave mirror. The size and focal length of the plano-convex and plano-concave mirrors are matched with the Powell lens. That is, the scaling factor of the beam scaling lens group needs to be determined based on the actual laser output beam size and the incident beam requirements of the Powell lens. Then, the size and focal length of the plano-convex and plano-concave mirrors are determined. For example, once the Powell lens is determined, the beam scaling lens group consists of a plano-convex mirror with a focal length of 200mm and a lens diameter of 25.4mm and a plano-concave mirror with a focal length of -50mm and a lens diameter of 25.4mm.

[0053] S400: Based on the beam diameter acquired by the image acquisition unit, the cylindrical concave lens and cylindrical convex lens are moved to the target position. By adjusting the distance between the cylindrical concave lens and cylindrical convex lens, the major axis and minor axis dimensions of the linear beam are changed to obtain the required linear spot size.

[0054] The device has a cylindrical concave lens mounted on a first rotating frame and a cylindrical convex lens mounted on a second rotating frame. The controller controls the movement of the first and second rotating frames to move the cylindrical concave lens and the cylindrical convex lens to the target position.

[0055] In step S400, before controlling the cylindrical concave lens and the cylindrical convex lens to move to the target position, the first rotating frame and the second rotating frame are controlled to rotate circumferentially according to the beam diameter of the Gaussian beam acquired by the image acquisition device, so as to select the cylindrical concave lens and the cylindrical convex lens that match the focal length.

[0056] Specifically, the first and second rotating lens frames each have four mounting holes, allowing the first rotating lens frame to mount four different types of cylindrical concave lenses with different focal lengths, and the second rotating lens frame to mount four different types of cylindrical convex lenses with different focal lengths. For example, one example of cylindrical concave and cylindrical convex lenses meeting the required dimensions is: a cylindrical concave lens with a length of 32mm, a width of 30mm, and a focal length of -150mm; and a cylindrical convex lens with a length of 32mm, a width of 30mm, and a focal length of 150mm.

[0057] The controller controls the first and second rotating frames to rotate circumferentially based on the spot size of the Gaussian beam acquired by the image acquisition device, in order to select the concave cylindrical lens and the convex cylindrical lens that match the focal length. It also automatically calculates the distance between the concave cylindrical lens and the convex cylindrical lens and controls the first and second rotating frames to move so that the concave cylindrical lens and the convex cylindrical lens move to the corresponding target position, thereby obtaining the required linear spot size.

[0058] Based on the variable-size linear beam shaping method provided in this embodiment, cylindrical concave lenses and cylindrical convex lenses with different focal lengths are placed on two rotatable frames, and the two rotatable frames can be rotated to select a suitable cylindrical lens to shape the beam. The major axis and minor axis dimensions of the linear beam are changed by adjusting the distance between the cylindrical concave lens and the cylindrical convex lens, thereby obtaining a linear beam size that meets the requirements.

[0059] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A variable size line beam shaping device, characterized by, The controller and the image collector, and a laser, a collimating mirror, a spot zoom lens group, a beam splitter, a Powell lens, a cylindrical concave lens and a cylindrical convex lens arranged in sequence along the main axis direction of the light path; further comprising a first rotating mirror frame and a second rotating mirror frame; The first rotating mirror frame and the second rotating mirror frame are respectively provided with a plurality of one-to-one corresponding mounting holes in the circumferential direction, the first rotating mirror frame is installed with cylindrical concave lenses of different focal lengths through the mounting holes, and the second rotating mirror frame is installed with cylindrical convex lenses of different focal lengths through the mounting holes; The cylindrical concave lens and the cylindrical convex lens are respectively movably arranged through the first rotating mirror frame and the second rotating mirror frame, and the distance between the two is adjusted to change the major axis size and the minor axis size of the linear light beam; The beam splitter is used for splitting the linear light beam into two Gaussian beams, one of which is transmitted to the Powell lens for beam shaping, and the other is transmitted to the image collector as an observation beam for observation; The image collector is used for collecting the beam diameter of the observation beam and is signal connected with the controller; The controller is configured to control the first rotating mirror frame and the second rotating mirror frame to rotate in the circumferential direction according to the beam diameter of the observation beam collected by the image collector, so as to select the cylindrical concave lens and the cylindrical convex lens with the focal length, calculate the beam diameter before splitting according to the beam diameter of the observation beam collected by the image collector, and control the first rotating mirror frame and the second rotating mirror frame to move according to the beam diameter before splitting, so as to move the selected cylindrical concave lens and cylindrical convex lens to the target position, dynamically adjust the distance between the cylindrical concave lens and the cylindrical convex lens, change the major axis size and the minor axis size of the linear light beam, and thus obtain the linear light spot with the required variable size.

2. The variable-size line-shaped beam shaper of claim 1, wherein, Further comprising a convex lens arranged between the beam splitter and the image collector, the convex lens is used for focusing the Gaussian beam to the image collector.

3. The variable-size line-shaped beam shaper of claim 2, wherein, The image collector collects the beam diameter of the focused Gaussian beam, and the controller calculates the beam diameter before splitting according to the beam diameter collected by the image collector, and controls the first rotating mirror frame and the second rotating mirror frame to move according to the beam diameter before splitting.

4. The variable-size line-shaped beam shaper of claim 1, wherein, The spot zoom lens group comprises a plano-convex lens and a plano-concave lens, and the size and focal length of the plano-convex lens and the plano-concave lens are matched with the Powell lens.

5. The variable-size line-shaped beam shaper of claim 1, wherein, The incident spot diameter size of the Powell lens is 0.8mm, and the minor axis size of the output beam of the Powell lens is equal to the incident spot diameter size.

6. The variable-size line-shaped beam shaper of claim 1, wherein, The beam splitter is a non-polarized beam splitter, and the reflection light to transmission light ratio R:T of the beam splitter is 10:

90.

7. A variable size line beam shaping method employing the variable size line beam shaping device according to any one of claims 1 to 6, characterized by, The steps include: generating laser by a laser; collimating the laser by a collimating mirror to obtain parallel light; reducing the parallel light to the required size by a spot zoom lens group, and splitting the parallel light into two Gaussian beams by a beam splitter, one of which is transmitted to a Powell lens, and the other is transmitted to an image collector as an observation beam for observation; According to the light beam diameter before the light splitting, the cylindrical concave lens and the cylindrical convex lens are moved to the target position, and the major axis size and the minor axis size of the linear light beam are changed by adjusting the distance between the cylindrical concave lens and the cylindrical convex lens, so as to obtain the required linear light spot size.

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