Laser processing device with three-dimensional alignment correction function

Abstract

To suppress deterioration in repetition precision of a mechanism part and position precision of a laser irradiation part under an influence of straining of a support mechanism through three-dimensional alignment correction.SOLUTION: A mechanism which can simultaneously measure position errors of an object of irradiation and a focus position of laser light in a plane direction and a depth direction and a system which can control relative positions of the object of irradiation and the focus position of the laser light in three-dimensional directions repeatedly perform control over and confirmation of a direction in which the errors are decreased to lessen the errors into a resolution range of the control.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laser processing device with improved alignment correction accuracy. [Background technology]

[0002] In the method of correcting the alignment of a processing device using a camera, an image of a workpiece without any misalignment is captured and stored as reference data. During processing, an image of the workpiece to be processed is captured, and the difference in position from the reference data is used as the correction amount. This is achieved by moving the workpiece or tool in a direction that eliminates the misalignment according to the correction amount.

[0003] However, if the temperature is different between when the reference data is stored and when the workpiece is processed, the distortion of the structure will be different, so the camera will capture the image at a different position, resulting in a discrepancy in the acquired data.In addition, errors will occur due to the repeatability of the mechanism for moving the camera and the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-214413 A [Non-patent literature]

[0005] [Non-Patent Document 1] Ball screw lead accuracy JIS standard JIS B 1192 (ISO 3408) Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved is the positioning error caused by temperature characteristics and repeatability of the mechanism, which occurs in alignment correction using a camera and a drive device for XYZ directions. [Means for solving the problem]

[0007] The present invention solves this problem by providing a structure that can directly measure the deviation from the target position at the processing position, and a control method that converges the amount of deviation within a certain range. Effect of the Invention

[0008] The laser processing apparatus of the present invention constantly monitors the amount of deviation directly from the target processing position, and therefore has the advantage of being able to improve deviations caused by structural distortion and the repeatability accuracy of the positioning mechanism. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a laser processing device (Example 1). [Diagram 2] FIG. 2 is an explanatory diagram showing a method for performing alignment correction (Example 2). [Diagram 3] FIG. 3 is an explanatory diagram showing a state in which an angle difference occurs between the coordinates of the camera coordinate system and the control coordinate system (Example 3). [Figure 4] FIG. 4 is an explanatory diagram comparing the alignment correction method with a conventional method (Example 4). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In a structure in which the laser irradiation unit and three-dimensional position measurement unit are integrated, a structure has been realized that can measure the three-dimensional position without moving the position of the three-dimensional position measurement unit when the center of the laser light is near the target position. EXAMPLES

[0011] 1 is a block diagram of an embodiment of the device of the present invention, in which 180 is a laser irradiation unit, 150 is a distance measurement unit, 170 is an XY position measurement unit (camera), and each of these is integrated into a laser irradiation measurement unit 190. Explanation of optical components 181 to 184 is omitted.

[0012] The controller 140 can control the position of the laser irradiation measurement unit 190 based on position information sent from the distance measurement unit 150 and the image processing unit 130 .

[0013] The laser power supply 110 receives a laser irradiation command from the controller 140, irradiates the laser, and via the optical fiber 120 and the laser irradiation unit 180, processing can be performed on the irradiation target object 160.

[0014] With this structure, the control amount for performing alignment correction can be obtained simultaneously without moving the alignment adjustment means. EXAMPLES

[0015] FIG. 2 shows a procedure for controlling the irradiation position based on setting data and measurement data.

[0016] Set the irradiation position on the screen. The position 250 (X0, Y0) on the XY plane is the value obtained by the image processing unit 130 as the center coordinate of the irradiation light when the pilot lamp attached to the laser module is lit or when a weak laser is irradiated, and the vertical position 210 Z0 is the value measured by the distance measurement sensor 150 when the center of the beam waist of the laser light is aligned with the surface of the workpiece.

[0017] The allowable range (the allowable amount of deviation from the target position) is set to an arbitrary value in advance. The allowable range on the XY plane is set to 220 (Xa, Ya), and the allowable range in the distance direction is set to 230 Za.

[0018] A target position 270 (X1, Y1) of the horizontal laser irradiation is obtained by image processing of the target object.

[0019] The control amount for moving the laser beam to the target position in the horizontal direction can be calculated using 250 (X0, Y0) and 270 (X1, Y1), as shown in the following formula. The control amount is less than the control resolution of the mechanism.

[0020]

number

[0021] A target position 290 Z1 of laser irradiation in the vertical direction is obtained by measuring the target object with a distance sensor.

[0022] In the vertical direction, the control amount for moving the laser beam to the target position can be calculated using 210 Z0 and 290 Z1, and the formula is as follows.

[0023]

number

[0024] In the above formulas, values ​​that are not divisible by the resolution of the drive system require conversion to either round down or round up.

[0025] According to the above control amount, the 190 laser irradiation measurement unit is moved simultaneously in the XYZ directions. After that, ΔX, ΔY, and ΔZ are measured again, and if the values ​​are larger than the 220 XY allowable range (Xa,Ya) and the 230 Z allowable range (Za,), the 190 laser irradiation measurement unit is moved again according to the values ​​for correction. The vibration of the 190 laser irradiation measurement unit is suppressed by slowing down the moving speed as the deviation amount decreases. By repeating this process, the deviation of the target irradiation position can be converged to within the resolution of the drive system even if there is an effect of distortion of the structure. EXAMPLES

[0026] Figure 3 is a diagram showing the difference in direction when an angle occurs between the camera coordinate system and the control system coordinates due to aging, poor adjustment, etc. In this state, the control amount of the drive system calculated based on information obtained from the image is expressed by the following formula 3, and the difference from the target coordinates after n drives is as shown in formula 4. Here, XM is the control amount in the X direction, YM is the control amount in the Y direction, ΔXn is the difference from the target position in the X direction after n controls, and ΔYn is the difference from the target position in the Y direction after n controls.

[0027]

number

[0028]

number

[0029] [Table 1]

[0030] Table 1 above shows the results of correction when there is a difference of 15 degrees between the camera coordinate system and the control system coordinates, and the allowable difference from the target coordinates is set to 1 μm or less. The results of correction are visualized in Graph 1.

[0031] In this way, even if an angle error occurs between the camera coordinate system and the control system coordinates, the error can be kept within the target error range by repeatedly controlling based on the difference between the current position and the target position. EXAMPLES

[0032] In the method of step 401, since an image captured before production is compared with an image captured during production, positional errors occur due to differences in temperature before production and distortion of the mechanism due to aging. Also, since the position where the image is captured and the position where the processing is performed differ, positional errors occur within the positioning accuracy of the drive system when moving from the imaging position to the processing position during production.

[0033] In the method of step 402, it is judged whether the deviation is within the allowable range at that location before irradiating the laser light, and if it is outside the allowable range, the previous step is repeated, so the deviation amount is below the resolution for control. Also, since the deviation amount is calculated using the currently captured image, there is no difference in the distortion of the structure due to the temperature difference from when the reference data was acquired. [Industrial Applicability]

[0034] This system is used in production facilities and is extremely effective in improving the yield rate. [Explanation of symbols]

[0035] 110 Laser power supply 120 Optical Fiber 130 Image Processing Unit 140 Controller 150 Distance measurement sensor 160 Irradiation Object 170 XY position measurement section 180 Laser irradiation section 181 Input Lens 182 Half Mirror 183 Output Lens 184 Extender 190 Laser irradiation measurement unit 210 Target distance DATA 220 XY Tolerance 230 Z Tolerance 240 Image when measuring the center position of laser irradiation 250 Center coordinates of laser light 260 Image of the object before XY correction 270 Target position of laser irradiation calculated by image processing (X1, Y1) Image after 280 XY movement 290 Distance sensor measurement value 310 Camera X coordinate 311 Camera Coordinates 320 Control System Coordinates 321 Control System Coordinates 330 Direction difference from target position 331 Direction difference from target position 340 Laser beam current center position 341 Target Coordinates 410 Method of imaging the reference position before production 420 Method of checking position just before processing

Claims

[Claim 1] A laser processing device that detects the position of the object to be processed in the planar direction using a camera image, and in the vertical direction using a displacement sensor with the detection point on the optical axis of the camera lens system, and can simultaneously detect the difference in the irradiation position of the laser light relative to the position of the object to be processed in the planar direction and the vertical direction, and repeatedly controls the position of the structure in a direction that reduces the deviation of the irradiation position of the laser light relative to the position of the object to be processed using a mechanism that can drive a structure in the planar direction and vertical direction and irradiate laser light on the optical axis of the camera using a lens system.

Images