KR100538003B1 - Method of calibrating X-Y stage of laser system and an apparatus thereof - Google Patents

Abstract

The present invention relates to a method and a device for correcting a moving error of an X-Y stage of a laser system. Moving error correction method of the X-Y stage of the disclosed laser system, (a) placing a marking point in the lower center of the vision camera; (b) moving the X-Y stage by a predetermined set distance to a selected axis of the x-axis or the y-axis; (c) calculating the actual moving distance of the x-y stage by detecting the position of the marking point while moving the vision camera to one side on the selected axis; And (d) calculating a movement error of the X-Y stage. According to this, the user of the laser system can measure the movement error of the x-axis and y-axis stage at any time, and thus improve the laser processing quality of the laser system by correcting the movement distance of the xy stage by reflecting the measured movement error. Can be.

Description

Method of calibrating X-Y stage of laser system and its apparatus {Method of calibrating X-Y stage of laser system and an apparatus

The present invention relates to a method for correcting a movement error of an XY stage of a laser system, and more particularly, to measuring a position of a marking point on an XY stage using a vision camera to calculate a movement error of an XY stage of a laser system. A method of calibrating and an apparatus therefor.

1 is a schematic configuration diagram of a general laser system.

Referring to FIG. 1, a laser beam oscillated from the laser oscillator 10 is incident on the optical power detector 41 by reflecting some laser beams in the beam splitter 40 and the rest of the laser beams 20. The laser head 20 has a galvano scanner 21. The galvano scanner 21 has an x mirror 22 and a y mirror 23, and each of the mirrors 22 and 23 reflects the laser beams in the x and y directions, respectively, by a driver not shown. The laser beam from the galvano scanner 21 is irradiated onto the workpiece 35 on the X-Y stage 30.

The X-Y stage 30 has a structure in which the x stage 31 and the y stage 32 are stacked, and the stages 31 and 32 move in the uniaxial direction with each other by a driving unit such as servo motors 31a and 32a. Therefore, when the X-Y stage 30 moves diagonally without moving parallel to the x and y axes, the x stage 31 and the y stage 32 move together.

When the workpiece 35 is processed by the laser system, the laser head 20 is fixed and the laser work is performed while the X-Y stage 30 is moved.

Therefore, when processing a fine electronic circuit board, high precision processing is required, and therefore, precise movement of the X-Y stage 30 is required.

On the other hand, a laser interparameter correction tool (not shown) has been mainly used as a device for detecting a movement error of the X-Y stage. The laser interparameter correction tool first irradiates a laser beam to a target attached to one side of the x stage or the y stage, and receives the laser beam reflected therefrom to measure the position of the x stage or the y stage. Subsequently, the corresponding x stage or y stage was moved a predetermined distance, and the moving distance was measured again by using the laser interparameter correction tool, and the moving distance was compared with the actual moving distance to determine whether there was a moving error.

However, the cost of the laser interparameter correction tool used in the conventional method is expensive, a long time is required to install the correction tool, and there is a difficult problem to be installed whenever necessary.

SUMMARY OF THE INVENTION The present invention has been made to improve the above problems of the prior art, and provides a method and apparatus for correcting a moving error of an X-Y stage of a laser system which can be attached to a laser system and measure the moving error online.

In order to achieve the above object, the laser system of the present invention, in the laser system having an X-Y stage for moving the laser processing object,

An x-side linear guide and a y-axis linear guide installed horizontally in the plane of the X-Y stage above the X-Y stage;

A vision camera installed in each of the linear guides and observing the X-Y stage below while moving in the x-axis or y-axis; And

And a driving unit for driving the vision camera.

Preferably, the driving unit is a servo motor, and the vision camera is mounted on a screw installed inside the linear guide and rotated by the servo motor.

In order to achieve the above object, the movement error correction method of the X-Y stage of the laser system, (a) arranging the marking point in the lower center of the vision camera;

(b) moving the X-Y stage by a predetermined set distance to a selected axis among x- and y-axes;

(c) calculating the actual moving distance of the x-y stage by detecting the position of the marking point while moving the vision camera to one side on the selected axis; And

(d) calculating a movement error of the X-Y stage.

In the step (c), the actual moving distance of the X-Y stage is obtained by calculating the actual moving distance of the vision camera.

On the other hand, step (d), it is preferable to calculate the difference between the set distance and the actual moving distance to obtain the movement error.

Hereinafter, with reference to the accompanying drawings will be described in detail the moving error correction method and apparatus of the X-Y stage of the laser system according to an embodiment of the present invention. In this process, the thicknesses of layers or regions illustrated in the drawings are exaggerated for clarity.

Figure 2 is a schematic configuration diagram of a laser system according to a preferred embodiment of the present invention, the same reference numerals are used for the same components as the conventional invention, and detailed description thereof will be omitted.

Referring to FIG. 2, at least two vision cameras 135 and 145 are installed above the X-Y stage 30, and image signals of the vision cameras 135 and 145 are input to the controller 100. In addition, the vision cameras 135 and 145 are moved together with the X-Y stage 30 by receiving a movement command signal from the controller 100.

The vision cameras 135 and 145 are CCD cameras. A charge coupled device (CCD) is a photoelectric conversion sensor that converts light into an electrical signal. The intensity of light entering the lens (not shown) in front of the camera is first recorded in the CCD. At this time, the light of the captured image is separated into different colors by the RGB color filter attached to the CCD. The separated colors are converted into electrical signals by the hundreds of thousands of light sensors (corresponding to the pixels) that make up the CCD. The analog signal from the CCD is converted into digital signals of 0 and 1, and an image signal is produced and output. The vision cameras 135 and 145 receive light from the workpiece 35 to generate an electrical image signal. The image signal captured by the camera is transmitted to the controller 100.

3 is a perspective view schematically showing the configuration of the X-Y stage and the vision camera, Figure 4 is a perspective view showing the structure of the linear guide.

3 and 4, the x-axis linear guide 131 and the y-axis linear guide 141 are installed to cross at right angles above the X-Y stage 30. These linear guides 131 and 141 are installed horizontally from the plane of the X-Y stage 30. Each of the linear guides 131 and 141 is disposed downward so that the vision cameras 135 and 145 capture the XY stage 130 below, and the servo motors 132 and 142 which are driving parts are installed on one side of the linear guides 131 and 141. Move precisely in a straight line. A ball screw 133 is installed inside the linear guides 131 and 141, and a vision camera attachment part 134 is formed on a nut installed on the outer circumference of the ball screw 133 to rotate the servo motor 132. ) In a linear motion.

5 is a flowchart of a method for correcting a moving error of an XY stage of a laser system according to a preferred embodiment of the present invention, which is a flowchart of a method of measuring a moving error on an x-axis, and FIG. 6 is a view illustrating an XY stage and an x-axis vision camera. It is a figure explaining the process of moving to -x direction.

Referring to the drawings, a marking point M, which is a reference for imaging of the x-axis vision camera 135 and the y-axis vision camera 145, is prepared on the x stage 31, respectively. Then, the X-Y stage 30 is moved or the x-axis vision camera 135 is moved so that the marking point M is located at the center position of the coordinate system of the x-axis vision camera 135. Preferably, the X-Y stage 30 is moved so that the x-axis camera 135 is on one side of the x-axis linear guide 131 (step 201).

Next, the control unit 100 moves the x axis stage 31 to one side, for example, in the -x direction by a predetermined set distance d1 (step 202).

Subsequently, the controller 100 detects the marking point M while moving the x-axis vision camera 135 in the -x direction. Then, the position of the marking point M is measured to calculate the actual moving distance d2 of the x-axis stage 31 (step 203).

Subsequently, the difference between the actual moving distance d2 of the x-axis stage 31 and the moving distance d1 set by the control unit 100 is obtained to calculate the x-axis moving error (step 204). That is, the x-axis movement error Ex of the x stage 31 is calculated by the equation (1).

Ex = d1-d2

Next, if it is determined that the x-axis movement error Ex calculated in step 204 is larger than the error range which is a predetermined set value (step 205), the correction value of the movement error of the x-axis stage 31 is calculated ( Step 206). The subsequent x-axis movement of the X stage is moved in consideration of the corrected value.

The correction value of the movement error of the x-axis stage 31 may be calculated by a simple proportional formula to uniformly adjust the output pulse value from the controller 100 to the servomotor 132. That is, the control unit 100 converts the movement command d3 of the x-axis stage 31 into the corrected value d and outputs the calculated value by the equation (2).

d = d3 x (d2 / d1)

Here, d3 is an output value from the controller 100 and d is a corrected output value.

On the other hand, if it is determined that the x-axis movement error Ex calculated in step 204 is equal to or less than a predetermined set value (step 205), the process of correcting the movement error of the x-axis stage 31 is terminated.

In FIG. 5, the method for correcting the movement error of the x-axis stage 31 has been described. However, since the method for correcting the movement error of the y-axis stage 32 is substantially the same as that described above, a detailed description thereof will be omitted.

As described above, when using the laser system equipped with the movement error correction device of the XY stage according to the present invention, the user of the laser system can measure the movement error of the x-axis and y-axis stages at any time, and thus the measured The laser processing quality of the laser system can be improved by correcting the moving distance of the xy stage by reflecting the movement error.

Although the present invention has been described with reference to the embodiments with reference to the drawings, this is merely exemplary, it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined only by the appended claims.

1 is a schematic configuration diagram of a general laser system.

2 is a schematic structural diagram of a laser system according to a preferred embodiment of the present invention.

3 is a perspective view schematically showing the configuration of the X-Y stage and the vision camera.

4 is a perspective view showing the structure of the linear guide.

5 is a flowchart illustrating a moving error correction method of an X-Y stage of a laser system according to an exemplary embodiment of the present invention.

6 is a view for explaining a process of moving the X-Y stage and the x-axis vision camera in the -x direction.

* Description of Signs of Major Parts of Drawings *

10: laser oscillator 20: laser head

21: Galvano Scanner 30: X-Y Stage

31: x stage 32: y stage

35: workpiece 40: beam splitter

41: optical power detector 131,141: linear guide

132, 142: servomotor 133: ball screw

134: camera attachment portion 135, 145: vision camera

Claims (6)

A laser system having an X-Y stage for moving a laser object, An x-side linear guide and a y-axis linear guide installed perpendicular to each other in a plane above the X-Y stage; A plurality of vision cameras installed in the linear guides and observing the X-Y stage below while moving in the x-axis or y-axis; And And a driving unit for driving the vision camera. The driving unit is a servo motor, and the vision camera is installed inside the linear guide laser system, characterized in that mounted on a screw rotated by the servo motor. delete A laser system having an XY stage for moving a laser processing object, an x-side linear guide and a y-axis linear guide horizontally disposed in a plane of the XY stage above the XY stage, and provided in the respective linear guides Or a vision camera for observing the XY stage below the yarn when moved in the y axis, and a driving unit for driving the vision camera. (a) arranging a marking point in a lower center of the vision camera; (b) moving the X-Y stage by a predetermined set distance to a selected axis among x- and y-axes; (c) calculating the actual moving distance of the x-y stage by detecting the position of the marking point while moving the vision camera to one side on the selected axis; And (d) calculating a movement error of the X-Y stage; and moving error correction method of the X-Y stage of the laser system. The method of claim 3, wherein In the step (c), the movement error correction method of the X-Y stage of the laser system, characterized in that to calculate the actual movement distance of the X-Y stage by calculating the actual movement distance of the vision camera. The method of claim 3, wherein In the step (d), the movement error correction method of the X-Y stage of the laser system, characterized in that for calculating the difference between the set distance and the actual moving distance. The method of claim 3, wherein The driving unit is a servo motor, and the vision camera is installed inside the linear guide is mounted to a screw rotated by the servo motor, the movement error correction method of the X-Y stage of the laser system.