Laser scanning system and method thereof

Abstract

The present invention relates to a laser scanning system for scanning on an imaging plane, comprising a frame, a laser emitting unit, a focusing unit and a deflection unit. The laser scanning system also comprises a beam quality analyzer and a controller, wherein: the beam quality analyzer is used to measure the data of the light spot morphology, and the beam quality analyzer is electrically connected to the controller for inputting the data into the controller; the controller is electrically connected to the laser emitting unit, the deflection unit and the focusing unit. The data of the light spot is measured by the beam quality analyzer, and the real-time instruction is calculated by the controller, so that the controller controls the light spot to move along the scanning path through the deflection unit, and also controls the defocus state of the light spot in real time through the focusing unit, so that the projection width of the light spot of the scanning beam on the imaging plane along the normal direction of the path to be scanned remains unchanged, so as to achieve the effect of ensuring the uniformity of the width and energy density of the scanning path.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing, and in particular to a laser scanning system and method thereof. Background Art

[0002] The existing laser plane scanning device controls the deflection unit to deflect the scanning beam and then control its movement on the imaging plane;

[0003] However, since the incident angle of the scanning beam deviates from the vertical incident state after deflection, the laser spot on the imaging plane will undergo elliptical distortion, namely deflection elliptical distortion; in addition, due to the principle limitations of the laser, the divergence angle of the scanning beam is usually inconsistent in the XY direction, so that when the scanning beam spot is defocused, the spot will also produce elliptical distortion, namely defocus elliptical distortion;

[0004] At present, most of them adopt the method of ensuring the focus of the laser spot, avoiding the use of defocused spots to avoid defocused elliptical distortion. At the same time, focusing can also reduce the spot area, thereby reducing or even eliminating the influence of deflection elliptical distortion;

[0005] However, as the scanning light beam moves on the imaging plane, the optical path changes, which may cause the light spot to be out of focus. Therefore, in order to maintain the focusing state of the laser spot, a focusing unit is generally used to compensate for the change in optical path caused by the movement of the scanning light beam.

[0006] When the scanning beam is deflected to the edge of the imaging plane, even if the laser spot is in a focused state on the imaging plane, its incident angle obviously deviates from the vertical incidence state, so that the actual spot on the imaging plane will still undergo elliptical distortion, and the major axis of the elliptical distortion changes dynamically with the deflection direction of the scanning beam, resulting in the scanning path width continuously changing with the movement of the spot in the imaging plane. Under the condition of unchanged laser power, the energy density on the scanning path is different, that is, the scanning path width and energy density are both unstable.

[0007] The current common practice is to limit the maximum scanning deflection angle, but this will affect the application potential of laser plane scanning devices in additive manufacturing equipment. There are public reports of using large-aperture focusing units to cover the entire imaging plane to ensure that the scanning beam always scans the imaging plane vertically, but its high cost is not conducive to popularization and application. Summary of the invention

[0008] Based on this, it is necessary to provide a laser scanning system and method that can keep the projection width of the light spot of the scanning beam on the imaging plane along the normal direction of the scanning path unchanged to address the problem of uneven width and energy density of the scanning path of the scanning beam.

[0009] A laser scanning system for scanning on an imaging plane comprises a frame, a laser emitting unit, a focusing unit and a deflection unit, wherein the laser scanning system further comprises a beam quality analyzer and a controller, wherein: the beam quality analyzer is used to measure data on the spot shape of the scanning beam emitted by the laser emitting unit incident on the center position of the imaging plane, the beam quality analyzer is electrically connected to the controller, and is used to input data into the controller; the controller is electrically connected to the laser emitting unit, the deflection unit and the focusing unit, and the controller is used to calculate the input measurement data and obtain real-time instructions, so as to control the deflection unit to make the scanning beam move along the path to be scanned, and at the same time, by real-time control of the focusing unit, the projection width of the spot of the scanning beam on the imaging plane along the normal direction of the path to be scanned remains unchanged.

[0010] In the above-mentioned laser scanning system, the data of the light spot is measured by a beam quality analyzer, and real-time instructions are calculated by a controller, so that the controller controls the movement of the light spot along the scanning path through the deflection unit, and also controls the defocus state of the light spot in real time through the focusing unit, so that the projection width of the light spot of the scanning beam on the imaging plane along the normal direction of the path to be scanned remains unchanged, thereby achieving the effect of ensuring the uniformity of the width and energy density of the scanning path.

[0011] In one of the embodiments, the frame is provided with a collimator, the light inlet of the collimator is connected to the output optical fiber of the laser emitting unit, and the light outlet of the collimator is connected to the light inlet of the focusing unit.

[0012] Such an arrangement enables the laser beam outputted by the laser emitting unit to be processed into a nearly parallel beam by the collimator after being introduced into the collimator through the output optical fiber.

[0013] In one embodiment, the frame is further provided with an optical substrate, the collimator, the focusing unit and the deflection unit are all arranged on the optical substrate, and the optical axis of the collimator, the optical axis of the focusing unit and the optical axis of the light entrance of the deflection unit are coaxially arranged.

[0014] In one embodiment, the deflection unit includes an X-axis motor and a Y-axis motor whose output axes are perpendicular to each other, the output axis of the X-axis motor is provided with an X-axis reflector, and the output axis of the Y-axis motor is provided with a Y-axis reflector.

[0015] Such an arrangement enables the X-axis reflector and the Y-axis reflector to drive the scanning light beam to move continuously on the imaging plane when the X-axis reflector and the Y-axis reflector are continuously deflected, and form a light spot scanning line on the imaging plane.

[0016] A laser scanning method, using the above laser scanning system, the laser scanning method comprises the following steps:

[0017] S100, measuring the spot data of the scanning beam emitted by the laser emitting unit by a beam quality analyzer, inputting the spot data and a plurality of sets of vector data of the paths to be scanned into the controller, and calculating a two-dimensional array of the spot data table by the controller;

[0018] S200, calculating a set of angles α between the path to be scanned and the long axis of the light spot through the controller, and sending instructions to the deflection unit and the laser emitting unit through the controller to control the scanning light beam to be in an initial state;

[0019] S300, the controller calculates the instantaneous position of the light spot through the vector data, and controls the deflection unit to make the light spot move along the group of paths to be scanned;

[0020] S400, the controller calculates and obtains the focus control instruction and the defocus control instruction according to the instantaneous position, the angle α and the two-dimensional array of the light spot data table, and superimposes the two and sends them to the focusing unit in real time, so that the projection width of the light spot along the normal direction of the scanning path of the group remains unchanged.

[0021] In one embodiment, the S100 includes

[0022] S101, using the beam quality analyzer to measure the spot shape of the scanning beam vertically incident on the center position of the imaging plane, including a negative defocused spot, a focused spot, and a positive defocused spot, to record the major axis width, minor axis width, and major axis azimuth of the spot in the focused and defocused states, and input the recorded data into the controller to generate a center spot data table; and

[0023] S102, the controller calculates the spot data at different positions of the imaging plane according to the central spot data table and the projection geometric model of the deflection unit, so as to obtain a two-dimensional array of the spot data table including the long and short axis widths and long axis azimuth angle data of the negative defocused spot, the focused spot, and the positive defocused spot at each coordinate position within the entire imaging plane; and

[0024] S103, inputting the vector data of the path to be scanned, including a plurality of data sets of the starting point coordinates, end point coordinates, speed, width and laser power of the path to be scanned, into the controller.

[0025] In one embodiment, the S200 includes

[0026] S201, reading, by the controller, a set of the starting point coordinates and the end point coordinates of the path to be scanned in the vector data, and calculating the angle α between the set of the path to be scanned and the long axis of the light spot; and

[0027] S202, the controller sends a positioning instruction to the deflection unit, and controls the scanning light beam to deflect to the starting position of the group of paths to be scanned through the deflection unit; and

[0028] S203, the controller reads the set value of the laser power of the group of paths to be scanned, and sends a power adjustment instruction to the laser emitting unit to control the output power of the laser emitting unit to be consistent with the laser power set value.

[0029] In one embodiment, the S300 includes

[0030] S301, the controller reads the set value of the speed of the group of paths to be scanned, and calculates in real time the coordinate data of the instantaneous position of the light spot in the process of moving from the starting point to the end point along the path to be scanned; and

[0031] S302: Sending the calculated coordinate data to the deflection unit in real time through the controller to control the light spot to move along the path to be scanned in the imaging plane.

[0032] In one embodiment, the S400 includes

[0033] S401, the controller reads the set value of the width of the path to be scanned, and calculates the total optical path of the scanning light beam from the center of the focusing unit to the imaging plane according to the coordinate data of the instantaneous position of the light spot, so as to obtain the focus control instruction for compensating for the change of the optical path and maintaining the focus of the light spot; and

[0034] S402, calculating in real time the projection width of the light spot on the normal line of the path to be scanned at each of the instantaneous positions according to the angle α and the two-dimensional array of the light spot data table, and then deriving the defocus control instruction for width compensation according to the projection width; and

[0035] S403, the controller superimposes the focus control instruction and the defocus control instruction and sends them to the focus adjustment unit in real time; and

[0036] S404, repeatedly executing the above steps S401, S402 and S403 during the scanning of the path to be scanned, so that during the scanning, the projection width of the light spot on the imaging plane on the normal line of the moving direction is equal to the width setting value of the path to be scanned.

[0037] In one embodiment, the total optical path of the scanning light beam from the center of the focusing unit to the imaging plane is equal to the sum of the B value and the P value, wherein:

[0038] The B value is the optical path between the focusing unit and the X-axis reflector;

[0039] The P value is the sum of the projected optical paths of the X-axis reflector and the Y-axis reflector. The P value formula is (((y 2 +A 2 ) 1 / 2 +e) 2 +x 2 ) 1 / 2 ;

[0040] Among them, y is the Y-axis coordinate value of the scanning point on the imaging plane, x is the X-axis coordinate value of the scanning point on the imaging plane, e is the center distance between the X-axis reflector and the Y-axis reflector, and A is the vertical distance from the center of the Y-axis reflector to the imaging plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0042] Figure 2 It is a schematic diagram of the normal viewing direction of the imaging plane when the light spot undergoes elliptical deflection distortion;

[0043] Figure 3 It is a schematic diagram of the three-dimensional structure of the imaging plane when the light spot is positively defocused;

[0044] Figure 4 It is a schematic diagram of the three-dimensional structure of the imaging plane when the light spot is negatively defocused;

[0045] Figure 5 It is a schematic diagram of the front view direction of the scanning path in the imaging plane in the prior art;

[0046] Figure 6 It is a schematic diagram of the scanning path in the front view direction of the imaging plane in the present invention;

[0047] Figure 7 Schematic diagram of the optical path structure between the focusing unit, the deflection unit and the imaging plane.

[0048] Main component symbols

[0049] 100, frame; 10, laser emitting unit; 11, output optical fiber; 20, focusing unit; 30, deflection unit; 31, X-axis motor; 32, X-axis reflector; 33, Y-axis motor; 34, Y-axis reflector; 40, collimator; 50, optical substrate;

[0050] 200. Imaging plane.

[0051] The above description of the main component symbols is combined with the accompanying drawings and specific implementation methods to further illustrate the present invention in detail. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0055] The present invention first provides a laser scanning system for scanning on an imaging plane 200. Figure 1 As shown, it includes a frame 100, a laser emitting unit 10, a focusing unit 20 and a deflection unit 30, and the laser scanning system also includes a beam quality analyzer and a controller, wherein:

[0056] The beam quality analyzer is used to measure the data of the spot shape of the scanning beam emitted by the laser emitting unit 10 incident on the center position of the imaging plane 200. The beam quality analyzer is electrically connected to the controller to input the data into the controller;

[0057] The controller is electrically connected to the laser emitting unit 10, the deflection unit 30 and the focusing unit 20. The controller is used to calculate the input measurement data and obtain real-time instructions so as to control the deflection unit 30 to move the scanning light beam along the path to be scanned, and at the same time, to control the focusing unit 20 in real time so that the projection width of the light spot of the scanning light beam on the imaging plane 200 along the normal direction of the path to be scanned remains unchanged.

[0058] Here, the spot morphology measured by the beam quality analyzer includes a negative defocused spot, a focused spot, and a positive defocused spot, so as to record the spot data such as the major axis width, minor axis width, and major axis azimuth of the spot in the focused and defocused states.

[0059] The X-axis coordinate value of the scanning point on the imaging plane 200 is defined as x, and the Y-axis coordinate value of the scanning point on the imaging plane 200 is defined as y;

[0060] When the deflection unit 30 is controlled to move the scanning beam along the path to be scanned, the incident angle of the scanning beam deviates from the vertical incident state after deflection, so that the projection spot on the imaging plane 200 will be elliptical distorted, that is, deflection elliptical distortion, for example:

[0061] Please refer to Figure 2 As shown, when x is not zero, the scanning light beam is irradiated on the X-axis of the imaging plane 200 and deviates from the center point, then the light spot is stretched in the X-axis direction, and the stretching coefficient is the inverse of the cosine function of the deflection angle of the scanning light beam in the X-axis;

[0062] When y is not zero, the scanning light beam is irradiated on the Y axis of the imaging plane 200 and deviates from the center point, then the light spot is stretched in the Y axis direction, and the stretching coefficient is the inverse of the cosine function of the deflection angle of the scanning light beam in the Y axis;

[0063] When x and y are not zero at the same time, when the scanning light beam is irradiated to the imaging plane 200, the light spot is stretched along the direction of the line connecting the center point of the imaging plane 200 and the coordinate (x, y) point.

[0064] By controlling the focusing and defocusing of the scanning light beam by the focusing unit 20, the projection spot can also be elliptical distorted, i.e., defocus elliptical distortion, for example:

[0065] When x and y are both equal to zero and the output focal length f1 of the focusing unit 20 is equal to the total optical path of the scanning beam, the scanning beam is irradiated at the center point of the imaging plane 200 and is in a focused state, and the projected spot size is the smallest and is a perfect circle;

[0066] Please refer to Figure 3 As shown, when the output focal length f1 of the focusing unit 20 is smaller than the total optical path of the scanning beam, the scanning beam is in a positive defocus state when irradiating the center point of the imaging plane 200, and due to the anisotropy of the divergence angle of the scanning beam, the projected spot size is larger than the focused spot and elliptical distortion occurs;

[0067] Otherwise, please refer to Figure 4 As shown, when the output focal length f1 of the focusing unit 20 is greater than the total optical path of the scanning beam, the scanning beam is in a negative defocus state when irradiating the center point of the imaging plane 200, the projected spot size is also larger than the focused spot and elliptical distortion occurs, and the major and minor axes of the ellipse exchange azimuth angles with those when positively defocused.

[0068] Therefore, in the process of scanning the light spot along the path to be scanned, according to the deflection elliptical distortion caused by the deflection of the light spot at any instantaneous position, the positive and negative defocus states of the scanning light beam are controlled in real time by the focusing unit 20, so as to adjust the major and minor axes of the ellipse of the projection light spot at the instantaneous position. The elliptical distortion of the projection light spot can be controlled in real time as needed, so that the projection width of the projection light spot along the normal direction of the path to be scanned remains unchanged, thereby achieving the effect of ensuring the uniformity of the width and energy density of the scanning path.

[0069] In some embodiments, when the scanning path is a semicircular arc with (x1,0) as the center, a radius of r, and an arc angle rotating from -90° counterclockwise to 90° on the imaging plane 200:

[0070] Please refer to Figure 5 As shown, in the prior art, the focusing unit 20 is only used to compensate for the change in the optical path when the scanning light beam moves, that is, the scanning light beam is always in a focused state on the imaging plane 200; to simplify the description, the deflection ellipse distortion of the light spot around the center (x1,0) is consistent with that at the center, and the light spot maintains a flat ellipse shape that is wide in the X-axis direction and unchanged in the Y-axis direction during the scanning of the semicircular arc. The path width of the semicircular arc at -90° is equal to the Y-axis width of the light spot, and the width is equal to the X-axis width of the light spot at 0°. When it reaches 90°, the path width becomes the Y-axis width of the light spot again. The width of the entire semicircular arc scanning path undergoes a continuous change from narrow to wide and from wide to narrow, so that the energy density on the scanning path is inconsistent under the condition that the laser power and speed setting values ​​remain unchanged;

[0071] Please refer to Figure 6 As shown, if the width Tw of the aforementioned semicircular arc scanning line at the 0° position is used as a reference, the deflection unit 30 drives the scanning light beam to scan the same semicircular arc again on the imaging plane 200, then the focusing unit 20 controls the scanning light beam to be in a defocused state when the scanning starts, so that the Y-axis width of the light spot becomes larger to Tw, and during the scanning process, the defocus amount of the scanning light beam is continuously adjusted so that the projection width of the light spot in the radial direction of the arc remains unchanged at Tw, then the semicircular arc scanning line obtained has a constant path width of Tw, and when the laser power and scanning speed are constant, the energy density on the scanning path is also constant.

[0072] Therefore, the focusing unit 20 actively adjusts the spot size of the laser spot at different positions and in different scanning directions of the imaging plane 200, so that when the laser spot undergoes deflection elliptical distortion and defocus elliptical distortion, a scanning path with uniform width can still be obtained, thereby ensuring the consistency of the laser energy density on the scanning path;

[0073] Secondly, during the scanning process, there is no need to use a perfect circular spot. A large defocused spot can be used to achieve wide path and high-speed scanning, which can significantly improve the forming efficiency of the solid filling section in the additive manufacturing equipment.

[0074] Thirdly, the deflection unit 30 can still maintain the controllability and isotropic consistency of the scanning path width in the edge area of ​​the imaging plane under large deflection angle scanning conditions, thereby obtaining a larger scanning range without the need for expensive and complex optical compensation and correction devices.

[0075] The frame 100 is provided with a collimator 40, the light inlet of the collimator 40 is connected to the output optical fiber 11 of the laser emitting unit 10, and the light outlet of the collimator 40 is connected to the light inlet of the focusing unit 20. The laser beam output by the laser emitting unit 10 is introduced into the collimator 40 through the output optical fiber 11, and then processed by the collimator 40 into a nearly parallel beam.

[0076] The frame 100 is also provided with an optical substrate 50, on which the collimator 40, the focusing unit 20 and the deflection unit 30 are all provided, and the optical axis of the collimator 40, the optical axis of the focusing unit 20 and the optical axis of the light entrance of the deflection unit 30 are coaxially arranged, so as to ensure that the approximately parallel light beam processed by the collimator 40 can be incident on the deflection unit 30 in a straight line without deviation.

[0077] Please refer to Figure 7 As shown, the deflection unit 30 includes an X-axis motor 31 and a Y-axis motor 33 whose output axes are perpendicular to each other. The output axis of the X-axis motor 31 is provided with an X-axis reflector 32 , and the output axis of the Y-axis motor 33 is provided with a Y-axis reflector 34 .

[0078] The X-axis motor 31 is used to drive the X-axis reflector 32 to rotate, so that the scanning light beam is deflected, and the projection spot of the scanning light beam on the imaging plane 200 moves along the X-axis direction; the Y-axis motor 33 is used to drive the Y-axis reflector 34 to rotate, so that the scanning light beam is deflected, and the projection spot of the scanning light beam on the imaging plane 200 moves along the Y-axis direction; therefore, when the X-axis reflector 32 and the Y-axis reflector 34 are continuously deflected, the scanning light beam can be driven to move continuously on the imaging plane 200 and form a spot scanning line on the imaging plane 200.

[0079] With respect to the above-mentioned laser scanning system, the present invention further provides a laser scanning method, which may include:

[0080] S100, measuring the spot data of the scanning beam emitted by the laser emitting unit 10 through a beam quality analyzer, inputting the spot data and multiple sets of vector data of the paths to be scanned into a controller, and calculating a two-dimensional array of the spot data table through the controller;

[0081] S200, a controller calculates a set of angles α between the path to be scanned and the long axis of the light spot, and sends a command to the deflection unit 30 and the laser emitting unit 10 through the controller to control the scanning beam to be in an initial state;

[0082] S300, the controller obtains the instantaneous position of the light spot through vector data calculation, and controls the deflection unit 30 to move the light spot along the group of paths to be scanned;

[0083] S400, the controller calculates and obtains the focus control instruction and the defocus control instruction according to the instantaneous position, the angle α and the two-dimensional array of the spot data table, and superimposes the two and sends them to the focusing unit 20 in real time, so that the projection width of the spot along the normal direction of the group of scanning paths remains unchanged.

[0084] In one embodiment of the present invention, step S100 may further include the following steps:

[0085] S101, using a beam quality analyzer to measure the spot shape of the scanning beam vertically incident on the center position of the imaging plane 200, including a negative defocused spot, a focused spot, and a positive defocused spot, to record the major axis width, minor axis width, and major axis azimuth of the spot in the focused and defocused states, and input the recorded data into a controller to generate a central spot data table; and

[0086] S102, the controller calculates the spot data at different positions of the imaging plane 200 according to the central spot data table and the projection geometric model of the deflection unit 30, thereby obtaining a two-dimensional array of the spot data table including the long and short axis widths and long axis azimuth angle data of the negative defocused spot, the focused spot, and the positive defocused spot at each coordinate position within the entire imaging plane 200; and

[0087] S103, inputting the vector data of the path to be scanned, including a plurality of data sets of the starting point coordinates, the end point coordinates, the speed, the width and the laser power of the path to be scanned, into the controller.

[0088] In one embodiment of the present invention, step S200 may further include the following steps:

[0089] S201, reading a set of starting point coordinates and end point coordinates of a path to be scanned in the vector data through a controller, and calculating an angle α between the set of paths to be scanned and the long axis of the light spot; and

[0090] S202, the controller sends a positioning instruction to the deflection unit 30, and controls the scanning light beam to deflect to the starting position of the group of paths to be scanned through the deflection unit 30; and

[0091] S203, the controller reads the set value of the laser power of the group of paths to be scanned, and sends a power adjustment instruction to the laser emitting unit 10 to control the output power of the laser emitting unit 10 to be consistent with the laser power set value.

[0092] In one embodiment of the present invention, step S300 may further include the following steps:

[0093] S301, the controller reads the set value of the speed of the group of paths to be scanned, and calculates in real time the coordinate data of the instantaneous position of the light spot in the process of moving from the starting point to the end point along the path to be scanned; and

[0094] S302 , sending the calculated coordinate data to the deflection unit 30 in real time through the controller to control the light spot to move along the path to be scanned on the imaging plane 200 .

[0095] In one embodiment of the present invention, step S400 may further include the following steps:

[0096] S401, the controller reads the set value of the width of the path to be scanned, and calculates the total optical path of the scanning light beam from the center of the focusing unit 20 to the imaging plane 200 according to the coordinate data of the instantaneous position of the light spot, thereby obtaining a focus control instruction for compensating for the change of the optical path and maintaining the focus of the light spot; and

[0097] S402, calculating in real time the projection width of the light spot at each instantaneous position on the normal line of the path to be scanned according to the angle α and the two-dimensional array of the light spot data table, and then obtaining a defocus control instruction for width compensation according to the projection width; and

[0098] S403, the controller superimposes the focus control instruction and the defocus control instruction and sends them to the focus adjustment unit 20 in real time; and

[0099] S404, repeatedly executing the above steps S401, S402 and S403 during the scanning of the path to be scanned, so that during the scanning, the projection width of the light spot on the imaging plane on the normal line of the moving direction is equal to the set width value of the path to be scanned.

[0100] In the above embodiment, the total optical path of the scanning light beam from the center of the focusing unit 20 to the imaging plane 200 is equal to the sum of the B value and the P value, where:

[0101] B value is the optical path between the focusing unit 20 and the X-axis reflector 32;

[0102] The P value is the sum of the projected optical paths of the X-axis reflector 32 and the Y-axis reflector 34. The P value formula is (((y 2 +A 2 ) 1 / 2 +e) 2 +x2 ) 1 / 2 .

[0103] Here, y is the Y-axis coordinate value of the scanning point on the imaging plane 200, x is the X-axis coordinate value of the scanning point on the imaging plane 200, e is the center distance between the X-axis reflector 32 and the Y-axis reflector 34, and A is the vertical distance from the center of the Y-axis reflector 34 to the imaging plane 200.

[0104] When it is necessary to scan other groups of paths to be scanned, as long as the vector data of the group of paths to be scanned is input into the control element in step S100, the scanning of the group of paths to be scanned can be completed by repeating steps S200, S300 and S400.

[0105] The specific implementation of the laser scanning method provided by the present invention has been introduced in detail when introducing the laser scanning system, and will not be repeated here.

[0106] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A laser scanning system for scanning on an imaging plane (200), comprising a frame (100), a laser emitting unit (10), a focusing unit (20) and a deflection unit (30), characterized in that: The laser scanning system also includes a beam quality analyzer and a controller, wherein: The beam quality analyzer is used to measure data of the spot shape of the scanning beam emitted by the laser emitting unit (10) incident on the center position of the imaging plane (200), and the beam quality analyzer is electrically connected to the controller and is used to input the data into the controller; The controller is electrically connected to the laser emitting unit (10), the deflection unit (30) and the focusing unit (20), and is used to calculate the input data and obtain real-time instructions, so as to control the deflection unit (30) so that the scanning light beam moves along the path to be scanned, and at the same time, the positive and negative defocus states of the scanning light beam are controlled in real time through the focusing unit (20), so as to adjust the major and minor axes of the ellipse of the projected light spot at the instantaneous position, so that the projection width of the light spot of the scanning light beam on the imaging plane (200) along the normal direction of the path to be scanned remains unchanged.

2. The laser scanning system according to claim 1, characterized in that: The frame (100) is provided with a collimator (40), the light inlet of the collimator (40) is connected to the output optical fiber (11) of the laser emitting unit (10), and the light outlet of the collimator (40) is connected to the light inlet of the focusing unit (20).

3. The laser scanning system according to claim 2, characterized in that: The frame (100) is further provided with an optical substrate (50), the collimator (40), the focusing unit (20) and the deflection unit (30) are all arranged on the optical substrate (50), and the optical axis of the collimator (40), the optical axis of the focusing unit (20) and the optical axis of the light entrance of the deflection unit (30) are coaxially arranged.

4. The laser scanning system according to claim 1, characterized in that: The deflection unit (30) comprises an X-axis motor (31) and a Y-axis motor (33) whose output axes are perpendicular to each other; the output axis of the X-axis motor (31) is provided with an X-axis reflector (32); and the output axis of the Y-axis motor (33) is provided with a Y-axis reflector (34).

5. A laser scanning method, characterized in that: Using the laser scanning system as described in any one of claims 1 to 4, the laser scanning method comprises the following steps: S100, measuring the spot data of the scanning light beam emitted by the laser emitting unit (10) by means of a beam quality analyzer, inputting the spot data and a plurality of sets of vector data of paths to be scanned into the controller, and calculating a two-dimensional array of a spot data table by means of the controller; S200, calculating a set of angles α between the path to be scanned and the long axis of the light spot through the controller, and sending instructions to the deflection unit (30) and the laser emitting unit (10) through the controller to control the scanning light beam to be in an initial state; S300, the controller calculates the instantaneous position of the light spot through the vector data, and controls the deflection unit (30) to move the light spot along the group of paths to be scanned; S400, the controller calculates and obtains a focus control instruction and a defocus control instruction according to the instantaneous position, the angle α and the two-dimensional array of the light spot data table, and superimposes the two and sends them to the focusing unit (20) in real time, so that the projection width of the light spot along the normal direction of the scanning path of the group remains unchanged.

6. The laser scanning method according to claim 5, characterized in that: The S100 includes S101, using the beam quality analyzer to measure the spot shape of the scanning beam vertically incident on the center position of the imaging plane (200), including a negative defocused spot, a focused spot and a positive defocused spot, to record the major axis width, minor axis width and major axis azimuth of the spot in the focused and defocused states, and input the recorded data into the controller to generate a central spot data table; as well as S102, the controller calculates the light spot data at different positions of the imaging plane (200) according to the central light spot data table and the projection geometric model of the deflection unit (30), thereby obtaining a two-dimensional array of the light spot data table including the long and short axis widths and long axis azimuth angle data of the negative defocused light spot, the focused light spot and the positive defocused light spot at each coordinate position within the entire imaging plane (200); as well as S103, inputting the vector data of the path to be scanned, including a plurality of data sets of the starting point coordinates, end point coordinates, speed, width and laser power of the path to be scanned, into the controller.

7. The laser scanning method according to claim 6, characterized in that: The S200 includes S201, reading, by the controller, a set of the starting point coordinates and the end point coordinates of the path to be scanned in the vector data, and calculating the angle α between the set of the path to be scanned and the long axis of the light spot; as well as S202, the controller sends a positioning instruction to the deflection unit (30), and controls the scanning light beam to deflect to the starting position of the group of paths to be scanned through the deflection unit (30); and S203, the controller reads the set value of the laser power of the group of paths to be scanned, and sends a power adjustment instruction to the laser emitting unit (10) to control the output power of the laser emitting unit (10) to be consistent with the laser power set value.

8. The laser scanning method according to claim 6, characterized in that: The S300 includes S301, the controller reads the set value of the speed of the group of paths to be scanned, and calculates in real time the coordinate data of the instantaneous position of the light spot in the process of moving from the starting point to the end point along the path to be scanned; as well as S302, sending the calculated coordinate data to the deflection unit (30) in real time through the controller to control the light spot to move along the path to be scanned on the imaging plane (200).

9. The laser scanning method according to claim 8, characterized in that: The S400 includes S401, the controller reads the set value of the width of the path to be scanned, and calculates the total optical path of the scanning light beam from the center of the focusing unit (20) to the imaging plane (200) according to the coordinate data of the instantaneous position of the light spot, thereby obtaining the focus control instruction for compensating for the change of the optical path and maintaining the focus of the light spot; as well as S402, calculating in real time the projection width of the light spot at each instantaneous position on the normal line of the path to be scanned according to the angle α and the two-dimensional array of the light spot data table, and then deriving the defocus control instruction for width compensation according to the projection width; as well as S403, the controller superimposes the focus control instruction and the defocus control instruction and sends the superimposed instruction to the focus adjustment unit (20) in real time; as well as S404, repeatedly executing the above steps S401, S402 and S403 during the scanning of the path to be scanned, so that during the scanning, the projection width of the light spot of the imaging plane (200) on the normal line of the moving direction is equal to the width setting value of the path to be scanned.

10. The laser scanning method according to claim 9, characterized in that: The total optical path of the scanning light beam from the center of the focusing unit (20) to the imaging plane (200) is equal to the sum of the B value and the P value, wherein: The B value is the optical path between the focusing unit (20) and the X-axis reflector (32); The P value is the sum of the projection optical paths of the X-axis reflector (32) and the Y-axis reflector (34). The P value formula is (((y 2 +A 2 ) 1 / 2 +e) 2 +x 2 ) 1 / 2 ; Wherein, y is the Y-axis coordinate value of the scanning point on the imaging plane (200), x is the X-axis coordinate value of the scanning point on the imaging plane (200), e is the center distance between the X-axis reflector (32) and the Y-axis reflector (34), and A is the vertical distance from the center of the Y-axis reflector (34) to the imaging plane (200).

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