A laser direct write lithography apparatus and method

Abstract

A kind of laser direct writing photoetching device and method, device includes mobile platform, laser control board, computer, exposure unit placed on mobile platform, camera unit connected with computer, platform controller, platform controller is connected with the controlled end of drive unit;Exposure unit includes closely arranged laser connected with laser control board signal, convex lens array, rotating mirror or galvanometer, F-θ scanning field lens, rotating angle drive of rotating mirror or galvanometer, the scattering light emitted by fiber array in closely arranged laser scatters to convex lens array, converts into multipath parallel light, then is irradiated to rotating mirror or galvanometer, again is focused as the light spot corresponding to each laser diode LD in closely arranged laser by F-θ scanning field lens, rotating mirror or galvanometer moves under the control of corresponding rotating angle drive.This application is suitable for any exposure requirement, whether it is fine line large energy exposure or mixed wave exposure, just by changing the type of laser diode LD, quantity can meet the requirement.

Description

Technical Field

[0001] This invention belongs to the technical field of PCB board manufacturing, and particularly relates to a laser direct-write lithography apparatus and method. Background Technology

[0002] Currently, the digital exposure equipment used for PCB board fabrication mainly includes DMD laser direct imaging exposure machines and single-point rotating mirror technology exposure machines.

[0003] The direct laser imaging exposure machine for DMD lasers is limited by the maximum optical power that a single DMD can withstand. When PCB board exposure requires high energy, the exposure speed is very slow. Furthermore, DMD fabrication technology belongs to MEMS fabrication technology, and the coating is mainly made of aluminum. Therefore, only laser exposure with wavelengths above 400nm can be used, which is difficult to meet the requirements for exposure of solder resist layers in the 355-455nm range. Currently, PCB board exposure for solder resist layers precisely meets the requirements of the 355-455nm wavelength range and high energy exposure, which DMDs can hardly meet.

[0004] Opal Technology's exposure solution is a high-speed rotating mirror solution, which can solve the above problems. However, the laser used is a high-speed pulsed laser. Due to the limitation of the laser's own power, this technology cannot meet the high-function exposure requirements. At the same time, only one wavelength of laser can be used. In addition, the exposure speed is also limited by the switching speed of the laser. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a laser direct-write lithography apparatus and method, the specific technical solution of which is as follows:

[0006] A laser direct-write lithography apparatus includes a moving platform, a laser control board, a computer, an exposure unit placed on the moving platform, a camera unit connected to the computer, and a platform controller. The platform controller is connected to the controlled end of a drive unit. The exposure unit includes a close-packed laser, a convex lens array, a rotating mirror or galvanometer, an F-θ scanning field mirror, and a rotation drive for the rotating mirror or galvanometer, all of which are signal-connected to the laser control board. Scattered light emitted from the fiber array in the close-packed laser is scattered onto the convex lens array, converting the scattered light into multiple parallel beams, which then illuminate the rotating mirror or galvanometer. The beams are then focused by the F-θ scanning field mirror into light spots corresponding to each laser diode (LD) in the close-packed laser. The rotating mirror or galvanometer moves under the control of the corresponding rotation drive.

[0007] Specifically, the rotating mirror is a polyhedral rotating mirror, and the galvanometer is a one-dimensional or two-dimensional galvanometer.

[0008] Specifically, the exposure unit array is provided in multiple ways.

[0009] Specifically, the densely packed laser includes an optical fiber array, a laser diode array, a densely packed optical fiber head, and a driver board. Each optical fiber is coupled to a corresponding laser diode (LD), and the interface of the densely packed optical fiber head is connected to the corresponding optical fiber. The optical fibers are arranged in several rows, with each row consisting of several optical fibers arranged at equal intervals. The laser diodes (LDs) are mounted on a bracket in a predetermined order. The laser diodes (LDs) are single-wavelength laser tubes or combinations of laser tubes with multiple wavelengths. The driver board drives the corresponding laser diode (LD) switches.

[0010] The laser control board is connected to the drive board, controlling each laser diode (LD) on the drive board to turn on or off according to a specified power; it is connected to the angle signal of the rotating mirror or galvanometer to determine its movement position; it is connected to the position signal of the platform controller to determine the position information of the platform; and it is connected to the computer to receive the image data corresponding to each exposure unit sent by the computer.

[0011] Specifically, the laser control board communicates with the computer via one of the following methods: Ethernet port, fiber optic cable, USB, or HDMI interface.

[0012] Specifically, the mobile platform includes a bottom platform and a gantry mounted on the bottom platform. The calibration camera and the suction cup move back and forth on the scanning axis of the bottom platform, which passes vertically through the gantry. The alignment camera and multiple exposure units are respectively mounted on the corresponding alignment axis and stepping axis on the gantry. The alignment axis and stepping axis are mounted parallel to the horizontal support column of the gantry. The rotation direction of the rotating mirror or galvanometer is perpendicular to the movement direction of the suction cup.

[0013] Specifically, the platform controller controls the calibration camera, suction cup, alignment camera, and exposure unit to move on corresponding axes and is connected to a computer. The computer calculates the position information of the calibration camera and alignment camera and sends the platform's position information to the laser control board.

[0014] The method using the laser direct-write lithography apparatus described above includes the following steps:

[0015] S1. Use a calibration camera to measure the installation position of each exposure unit, and the computer calculates the corresponding exposure image position based on the installation position of each exposure unit.

[0016] S2. Place the PCB board to be photolithographically printed on the suction cup, align it with the camera to capture the MARK mark on the PCB board, the computer calculates the placement position of the PCB board, and the computer performs corresponding movement operations on the original exposure image according to the placement position of the PCB board to ensure that the position of the exposure image corresponds one-to-one with the PCB board.

[0017] S3. Based on the calibration results of step S1, the computer cuts the image into several strips, each strip corresponding to the exposure area of ​​an exposure unit. In addition, the computer needs to pre-skew the image of each strip, and the calculation formula is as follows: ; ;in , The original coordinates are... The linear velocity of the light spot reflected by the galvanometer or rotating mirror on the PCB board is perpendicular to the direction of the suction cup movement. The linear velocity of the scan is in the direction of the suction cup's movement; x and y are the transformed coordinate points.

[0018] S4. The computer rasterizes the transformed exposure image and sends it to the laser control board of the corresponding exposure unit.

[0019] S5. The computer sends a signal to the platform controller, which controls the platform to move. The platform feeds back the position signal to the laser control board and sets it as the y-axis position. The galvanometer or rotating mirror starts to move and feeds back its position to the laser control board and sets it as the x-axis position. The laser control board then controls the switching of the laser diode (LD) based on the current x and y positions and the corresponding image points to achieve image exposure control.

[0020] Exposure control in step S5 includes precision mode; the specific steps are as follows:

[0021] S51. Set the distance between the centers of two adjacent light spots projected by the F-θ scanning field lens on the PCB board in the direction of the chuck movement (i.e., the y-axis) to be one step distance, and the step distance to be L; the number of light spots in the densely packed optical fiber is P; the time for the densely packed light spots to move one line is T.

[0022] S52. Calculate the size of a pixel in the rasterized exposure image from step S4, which is M = L / N, where N is a natural number; the time it takes for the densely packed light spots to move one line is T, and the distance the motion platform moves must strictly meet the following conditions:

[0023] When the remainder of P / N is zero, the platform's movement distance is ((P / N-1)+1 / N). The distance L; the number of light spots used is ((P / N-1)+1 / N) N; the platform's movement speed is: ((P / N-1)+1 / N) L / T; P / N values ​​are rounded down to the nearest integer;

[0024] When the remainder of P / N is not zero, the platform's movement distance is (P / N + 1 / N). The distance L; the number of light spots used is (P / N+1 / N). N platforms; the platform's movement speed is: (P / N+1 / N) L / T; the value of P / N is rounded down to the nearest integer.

[0025] The exposure control in step S5 includes a random mode; the specific steps are as follows: use all light spots for exposure, the computer calculates the platform's movement speed based on the energy required for the actual exposure of the PCB board, and then finds the N closest to the platform's movement speed to rasterize the image; the platform is exposed at the actual calculated speed, and for each light spot, the specific row of data is taken for exposure, and the data of the row closest to the platform's movement is used for exposure.

[0026] The advantages of this invention are: this application is applicable to any exposure requirements, whether it is high-energy exposure of fine lines or mixed-wave exposure, and the requirements can be met simply by changing the type and quantity of the laser diode LD. Attached Figure Description

[0027] Figure 1 This is a structural diagram of a laser direct-write lithography apparatus according to the present invention.

[0028] Figure 2(a) and Figure 2(b) show the arrangement of close-packed optical fibers.

[0029] Figure 3(a) is a schematic diagram of the structure of a close-packed fiber optic head.

[0030] Figure 3(b) is an enlarged view of the arrangement of the optical fiber in direction A in Figure 3(a).

[0031] Figure 4 This is a schematic diagram of the exposure unit structure.

[0032] Figure 5(a) is a schematic diagram of the 1 / 2 step mode.

[0033] Figure 5(b) is a schematic diagram of the 1 / 3 step mode.

[0034] In the picture:

[0035] 1. Bottom platform; 111. Scan axis; 112. Scan drive; 113. Calibration camera; 114. Suction cup;

[0036] 2. Gantry; 21. Horizontal support column; 221. Stepper axis; 222. Stepper drive; 223. Exposure unit;

[0037] 2230, Laser control board; 2231, Fiber optic array; 2232, Laser diode array; 2233, Closely packed fiber optic head; 2234, Driver board; 2235, Rotation driver; 2236, Convex lens array; 2237, Rotating mirror or galvanometer; 2238, F-θ scanning field mirror.

[0038] 231. Align the axis; 3. Computer Detailed Implementation

[0039] like Figure 1 and Figure 4 As shown, a laser direct-write lithography apparatus includes a mobile platform, a laser control board 2230, a computer 3, an exposure unit 223 placed on the mobile platform, a camera unit connected to the computer 3, and a platform controller.

[0040] The exposure unit 223 includes a densely packed laser, a convex lens array 2236, a rotating mirror or galvanometer 2237, an F-θ scanning field mirror 2238, and a rotation drive 2235 for the rotating mirror or galvanometer 2237, all connected to the laser control board. Scattered light emitted from the densely packed fiber optic head 2233 is directed to the convex lens array 2236, where it is converted into multiple parallel beams. These beams then illuminate the rotating mirror or galvanometer, and are focused by the F-θ scanning field mirror 2238 into light spots corresponding to each laser diode (LD). The rotating mirror is a polyhedral rotating mirror, and the galvanometer is a one-dimensional or two-dimensional galvanometer. The rotating mirror or galvanometer 2237 moves under the control of the corresponding rotation drive 2235. Multiple exposure units 223 are arrayed. Figure 1 There are six arrays in the middle.

[0041] The densely packed laser includes an optical fiber array 2231, a laser diode array 2232, a densely packed optical fiber connector 2233, and a driver board 2234. Each optical fiber is coupled to a corresponding laser diode (LD). The interface of the densely packed optical fiber connector 2233 is connected to the corresponding optical fiber. The optical fibers are arranged in several rows, with each row consisting of several optical fibers arranged at equal intervals. The laser diodes (LDs) are mounted on a bracket in a predetermined order. Each laser diode (LD) is a single-wavelength laser tube or a combination of laser tubes with multiple wavelengths. The driver board 2234 drives the corresponding laser diode (LD) switch. The optical fiber array 2231 is shown in Figures 2(a) and 2(b). In Figure 2(b), the white and black circles represent different wavelengths.

[0042] The laser control board 2230 is connected to the driver board 2234, controlling each laser diode (LD) on the driver board 2234 to turn on or off according to a specified power; it is connected to the angle signal of the rotating mirror or galvanometer to determine its movement position; it is connected to the position signal of the platform controller to determine the position information of the platform; and it is connected to the computer 3 to receive the image data corresponding to each exposure unit 223 sent by the computer 3. The laser control board 2230 communicates with the computer 3 via one of the following methods: Ethernet port, fiber optic cable, USB, or HDMI interface.

[0043] The mobile platform includes a bottom platform 1 and a gantry 2 mounted on the bottom platform 1. A calibration camera 113 and a suction cup 114 move back and forth on a scanning axis 111 of the bottom platform 1, which passes vertically through the gantry 2. An alignment camera and multiple exposure units 223 are respectively mounted on corresponding alignment axes 231 and stepping axes 221 on the gantry 2. The alignment axes 231 and stepping axes 221 are arranged parallel to each other on a horizontal support column 21 of the gantry 2. A stepping drive 222 drives the exposure units 223 to move back and forth on the stepping axis 221. The rotation direction of the rotating mirror or galvanometer 2237 is perpendicular to the movement direction of the suction cup 114.

[0044] The camera unit includes an alignment camera, a suction cup 114, and a calibration camera 113. It includes a suction cup 114 mounted on a platform, a calibration camera 113 located on the suction cup 114, and an alignment camera mounted on the gantry 2. The calibration camera 113 is fixed to the side of the suction cup 114. The suction cup 114 is used to adsorb the PCB board to be photolithographically processed and to calibrate the position and area range of each exposure unit 223. The alignment camera is moved to capture the MARK mark position of the exposed PCB board, determining the placement position of each PCB board. The computer 3 makes corresponding changes to the original exposure image based on the placement position of the PCB board, ensuring a one-to-one correspondence with the PCB board position.

[0045] The mobile platform includes a bottom platform 1 and a gantry 2 mounted on the bottom platform 1. The calibration camera 113 and the suction cup 114 move back and forth on the scanning axis 111 of the bottom platform 1 under the action of the scanning drive 112. The scanning axis 111 passes vertically through the gantry 2. The alignment camera and the exposure unit 223 are respectively mounted on the corresponding alignment axis 231 and stepping axis 221 on the gantry 2. The alignment axis 231 and the stepping axis 221 are mounted parallel to each other on the horizontal support column 21 of the gantry 2.

[0046] The platform controller controls the movement of the calibration camera 113 and the alignment camera, and simultaneously controls the movement of the suction cup 114 for exposure movement. It is connected to the computer 3, which calculates the position information of the calibration camera 113, the alignment camera and the laser control board 2230, and sends the platform's position information to the laser control board 2230.

[0047] The method using the above-described laser direct-write lithography apparatus includes the following steps:

[0048] S1. The installation position of each exposure unit 223 is measured using the calibration camera 113, and the computer 3 calculates the corresponding exposure image position based on the installation position of each exposure unit 223.

[0049] S2. Place the PCB board to be photolithographically printed on the suction cup 114, align it with the camera to capture the MARK mark on the PCB board, and the computer 3 calculates the placement position of the PCB board. Based on the placement position of the PCB board, the computer 3 performs corresponding movement operations on the original exposure image to ensure that the position of the exposure image corresponds one-to-one with the PCB board.

[0050] S3. Based on the calibration results of step S1, computer 3 cuts the image into several strips, each strip corresponding to the exposure area of ​​an exposure unit 223. Since the platform moves simultaneously with the galvanometer or rotating mirror, a horizontal line exposed by the galvanometer on the PCB board will become a diagonal line. To ensure the accuracy of the exposure image for each strip, computer 3 needs to pre-treat the image to guarantee the correctness of the final exposure image. The calculation formula is as follows: ; ;in , The original coordinates are... The linear velocity of the light spot reflected by the galvanometer or rotating mirror on the PCB board is perpendicular to the direction of movement of the chuck 114. y is the scanning linear velocity in the direction of motion of suction cup 114; x and y are the transformed coordinate points.

[0051] S4. The computer 3 rasterizes the transformed exposure image and sends it to the laser control board 2230, which then maps the rasterized image to the current optical unit station.

[0052] S5. Computer 3 sends a signal to the platform controller, which controls the platform's movement. The platform feeds back its position signal to the laser control board 2230, setting it as the y-axis position. The galvanometer or rotating mirror begins to move and feeds back its position to the laser control board 2230, setting it as the x-axis position. The laser control board 2230 then controls the switching of the laser diode LD based on its current x and y positions and the corresponding image points, thus achieving image exposure control. There are two specific exposure control modes:

[0053] When in Precision mode:

[0054] S51. Set the distance between the centers of two adjacent light spots projected by the F-θ scanning field lens 2238 onto the PCB board in the direction of platform movement (i.e., the y-axis) as one step distance, and the step distance as L; the number of light spots in the densely packed fiber is P; the time for the densely packed light spots to move one line is T.

[0055] S52. Calculate the size of a pixel in the rasterized exposure image from step S4 as M = L / N, where N is a natural number. The time T for the densely packed light spots to move one line and the distance the motion platform moves must strictly satisfy the following conditions:

[0056] When the remainder of P / N is zero, the platform's movement distance is ((P / N-1)+1 / N). The distance is L. The number of light spots used is ((P / N-1)+1 / N). For N platforms, the platform's movement speed is: ((P / N-1)+1 / N) L / T. The value of P / N is rounded down to the nearest integer.

[0057] When the remainder of P / N is not zero, the platform's movement distance is (P / N + 1 / N). The distance is L. The number of light spots used is (P / N + 1 / N). There are N platforms, and the platform's movement speed is: (P / N+1 / N) L / T. The value of P / N is rounded down to the nearest integer.

[0058] As shown in Figure 5(a), when P=16 and N=2, the time it takes for the closely packed light spots to move one row is equal to the distance the moving platform moves (7+1 / 2)L. Using 15 light spots ensures that each spot is exposed twice. If 16 spots are used, the last spot will be exposed three times, resulting in different exposure energy compared to other spots. The platform's movement speed is (7+1 / 2)L / T;

[0059] As shown in Figure 5(b), when P=16 and N=3, the time it takes for the closely packed light spots to move one row is equal to the distance the moving platform moves (5+1 / 3)L. 16 light spots are used. This ensures that each spot is exposed 3 times. The platform's movement speed is (5+1 / 3)L / T.

[0060] Therefore, in precision mode, the number of exposures at each point can be guaranteed to be consistent. The energy across all parts of the PCB board is consistent, but the platform's movement speed is discrete. Computer 3 needs to calculate the platform's movement speed based on the actual energy required for exposure on the PCB board, and then find the value N closest to this speed. The platform's movement speed is then recalculated based on the value of N.

[0061] When in random mode:

[0062] Random mode does not consider the uniformity of exposure energy and uses all light spots for exposure. Computer 3 needs to calculate the platform's movement speed based on the energy required for the actual exposure of the PCB board, and then find the N pairs of images closest to this speed for rasterization. The platform exposes at the actual calculated speed, and for each light spot, the specific row of data to be used is determined by the row of data that the platform's movement is closest to. Therefore, random mode exposure can maximize the use of laser energy, but the uniformity of the exposure energy cannot be guaranteed.

[0063] The specific exposure mode to use depends on the user's specific requirements.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser direct-write lithography apparatus, comprising a moving platform, a laser control board (2230), a computer (3), an exposure unit (223) placed on the moving platform, a camera unit connected to the computer (3), and a platform controller, wherein the camera unit includes an alignment camera, a suction cup, and a calibration camera, and the platform controller is connected to the controlled end of a drive unit; characterized in that, The exposure unit (223) includes a close-packed laser, a convex lens array (2236), a rotating mirror or galvanometer (2237), an F-θ scanning field mirror (2238), and a rotation drive (2235) for the rotating mirror or galvanometer (2237) connected to the laser control board. The scattered light emitted by the fiber array (2231) in the close-packed laser is scattered onto the convex lens array (2236), converting the scattered light into multiple parallel lights, which then illuminate the rotating mirror or galvanometer. The light is then focused by the F-θ scanning field mirror (2238) into a light spot corresponding to each laser diode LD in the close-packed laser. The rotating mirror or galvanometer (2237) moves under the control of the corresponding rotation drive (2235). The moving platform includes a bottom platform (1) and a gantry (2) set on the bottom platform (1). The calibration camera (113) and the suction cup (114) move back and forth on the scanning axis (111) of the bottom platform (1). The computer is used to calculate the placement position of the PCB board based on the MARK mark of the PCB board to be photolithographically etched placed on the suction cup held by the alignment camera. Based on the placement position of the PCB board, the computer performs corresponding movement operations on the original exposure image to ensure that the position of the exposure image corresponds one-to-one with the PCB board. The computer (3) is also used to calculate the corresponding exposure image position based on the installation position of each exposure unit (223) measured by the calibration camera, and to cut the image into several strips based on the calculation results. Each strip corresponds to the exposure area of ​​an exposure unit (223). In addition, the computer (3) needs to pre-treat each strip exposure image. The calculation formula is as follows: ; ;in , The original coordinates are... The linear velocity of the light spot reflected by the galvanometer or rotating mirror on the PCB board is the motion direction of the light spot perpendicular to the motion direction of the chuck (114); Let x be the scanning linear velocity in the direction of motion of the suction cup (114); and let x and y be the transformed coordinate points. The computer (3) rasterizes the transformed exposure image and sends it to the laser control board of the corresponding exposure unit (223); The computer (3) sends a signal to the platform controller, which controls the movement of the suction cup. The platform controller feeds back the position signal to the laser control board (2230) and sets it as the y-axis position. The galvanometer or rotating mirror starts to move and feeds back the position to the laser control board (2230) and sets it as the x-axis position. The laser control board (2230) then controls the switching of the laser diode LD according to the current x and y positions and the corresponding image points to achieve image exposure control.

2. The laser direct-write lithography apparatus according to claim 1, characterized in that, The rotating mirror is a polyhedral rotating mirror, and the galvanometer is a one-dimensional or two-dimensional galvanometer.

3. The laser direct-write lithography apparatus according to claim 1, characterized in that, The exposure unit (223) array is provided in multiple ways.

4. The laser direct-write lithography apparatus according to claim 1, characterized in that, The densely packed laser includes an optical fiber array (2231), a laser diode array (2232), a densely packed optical fiber head (2233), and a driver board (2234). Each optical fiber is coupled to a corresponding laser diode (LD). The interface of the densely packed optical fiber head (2233) is connected to the corresponding optical fiber. The optical fibers are arranged in several rows, with each row consisting of several optical fibers arranged at equal intervals. The laser diodes (LD) are installed on a bracket in a set order. The laser diodes (LD) are single-wavelength laser tubes or combinations of laser tubes with multiple wavelengths. The driver board (2234) drives the corresponding laser diode (LD) to switch. The laser control board (2230) is connected to the drive board (2234) to control each laser diode (LD) on the drive board (2234) to turn on or off according to a specified power; it is connected to the angle signal of the rotating mirror or galvanometer to determine its movement position; it is connected to the position signal of the platform controller to determine the position information of the platform; and it is connected to the computer (3) to receive the image data corresponding to each exposure unit (223) issued by the computer (3).

5. The laser direct-write lithography apparatus according to claim 4, characterized in that, The laser control board (2230) communicates with the computer (3) via one of the following methods: network port, fiber optic, USB, or HDMI interface.

6. The laser direct-write lithography apparatus according to claim 3, characterized in that, The platform controller controls the calibration camera (113), suction cup (114), alignment camera, and exposure unit (223) to move on the corresponding axes and is connected to the computer (3). The computer (3) calculates the position information of the calibration camera (113) and alignment camera and sends the position information of the platform to the laser control board (2230).

7. A method using a laser direct-write lithography apparatus according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Use a calibration camera (113) to measure the installation position of each exposure unit (223), and the computer (3) calculates the corresponding exposure image position based on the installation position of each exposure unit (223). S2. Place the PCB board to be photolithographically printed on the suction cup (114), aim the camera at the MARK mark of the PCB board, the computer (3) calculates the placement position of the PCB board, and the computer (3) performs corresponding movement operations on the original exposure image according to the placement position of the PCB board to ensure that the position of the exposure image corresponds one-to-one with the PCB board. S3. The computer (3) cuts the image into several strips according to the calibration result of step S1. Each strip corresponds to the exposure area of ​​an exposure unit (223). In addition, the computer (3) needs to pre-treat the exposed image of each strip. The calculation formula is as follows: ; ;in , The original coordinates are... The linear velocity of the light spot reflected by the galvanometer or rotating mirror on the PCB board is the motion direction of the light spot perpendicular to the motion direction of the chuck (114); Let x be the scanning linear velocity in the direction of motion of the suction cup (114); and let x and y be the transformed coordinate points. S4. The computer (3) rasterizes the transformed exposure image and sends it to the laser control board of the corresponding exposure unit (223). S5. The computer (3) sends a signal to the platform controller, which controls the movement of the suction cup. The platform controller feeds back the position signal to the laser control board (2230) and sets it as the y-axis position. The galvanometer or rotating mirror starts to move and feeds back the position to the laser control board (2230) and sets it as the x-axis position. The laser control board (2230) then controls the switching of the laser diode LD according to the current x and y positions and the corresponding image points to achieve image exposure control.

8. The method according to claim 7, characterized in that, Exposure control in step S5 includes precision mode; the specific steps are as follows: S51. Set the distance between the centers of two adjacent light spots projected by the F-θ scanning field lens (2238) on the PCB board in the direction of movement of the chuck (114), i.e. the y-axis direction, to be one step distance, and the step distance is L; the number of light spots in the densely packed optical fiber is P; the time for the densely packed light spots to move one row is T; S52. Calculate the size of a pixel in the rasterized exposure image from step S4, which is M = L / N, where N is a natural number; the time it takes for the densely packed light spots to move one line is T, and the distance the motion platform moves must strictly meet the following conditions: When the remainder of P / N is zero, the platform's movement distance is ((P / N-1)+1 / N). The distance L; the number of light spots used is ((P / N-1)+1 / N) N; the platform's movement speed is: ((P / N-1)+1 / N) L / T; P / N values ​​are rounded down to the nearest integer; When the remainder of P / N is not zero, the platform's movement distance is (P / N + 1 / N). The distance L; the number of light spots used is (P / N+1 / N). N platforms; the platform's movement speed is: (P / N+1 / N) L / T; the value of P / N is rounded down to the nearest integer.

9. The method according to claim 7 or 8, characterized in that, The exposure control in step S5 includes a random mode; the specific steps are as follows: use all light spots for exposure, the computer (3) calculates the platform's movement speed according to the energy required for the actual exposure of the PCB board, and then finds the N closest to the platform's movement speed and rasterizes the image; The platform exposes at the actual calculated speed. For each light spot, the specific row of data is taken for exposure. The data of the row that the platform moves closest to is used for exposure.

Images