JP2011230179A - Method for adjusting optical axis of laser machining apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively and accurately adjust an optical axis so that stable machining may be always conducted in an apparatus that conducts machining by scanning with a laser beam while moving the optical system.SOLUTION: The method for adjusting an optical axis is a method for adjusting the optical axis of a laser beam from a laser machining apparatus having a laser beam oscillator 1 and an optical system 3 movable over a predetermined range, and includes a first step and a second step. The first step is the step of setting an optical axis adjusting jig 5, in which a pinhole with a diameter smaller than that of the laser beam is formed, on the optical path of the laser beam. The second step is the step of detecting the output power of the laser beam that passes through the pinhole of the jig 5 by means of a power sensor 6 over the moving range of the optical system 3, and adjusting the attitude of the optical system 3 so that the detected values are equal and maximum in the moving range of the optical system.

Description

  The present invention relates to an optical axis adjustment method, and more particularly to a laser beam optical axis adjustment method for a laser processing apparatus having a laser oscillator and an optical system movable within a predetermined range.

  A device for irradiating a laser beam on a glass substrate constituting a solar cell and forming a groove in a semiconductor layer formed on the substrate and a device for dividing a glass substrate by irradiating a laser beam have been proposed. Yes. In such a laser processing apparatus, when the optical axis of the laser beam is deviated from the normal position, the processing accuracy is deteriorated due to the deterioration of the laser beam shape, or scanning along a desired line when the laser beam is scanned. Problems such as inability to occur.

  Therefore, in order not to reduce the processing accuracy, it is necessary to adjust so that the optical axis of the laser beam is in a normal position. When adjusting the optical axis, for example, while observing the laser irradiation position and the shape of the laser beam with a CCD camera, the operator manually adjusts the attitude of the mirrors constituting the optical system, and the irradiation position is set in advance. The laser beam is designed to have a predetermined shape so that it comes to the target position.

  Also, optical axis adjustment methods as shown in Patent Documents 1 and 2 have been proposed. In the method disclosed in Patent Document 1, first, in a laser processing apparatus, a target for detachably holding a crosshair for adjusting the optical axis, respectively, behind the front mirror of the two adjacent mirrors and in front of the rear mirror. A holder is provided. In adjusting the optical axis, a cross hair is inserted into the laser beam path, and the operator manually adjusts the image based on the image.

  In Patent Document 2, an optical axis adjusting device is provided in the laser optical path. This optical axis adjusting device is composed of two separation mirrors and an actuator that drives them separately.

  Here, in various apparatuses using a laser beam, the laser beam is scanned by moving a mirror constituting an optical system. In such an apparatus, the mirror is moved along the guide rail, but the moving direction of the mirror and the optical axis of the laser beam may be misaligned. In such a case, the performance of the apparatus is reduced. Therefore, Patent Document 3 discloses an optical axis adjustment method that eliminates errors in the parallel relationship between the optical axis of the moving optical system and the rail.

JP-A-11-226767 JP 2005-103598 A JP-A-9-27128

  In the method of adjusting the optical axis while observing the shape or the like of the laser beam with a conventional CCD camera, or in the apparatus disclosed in Patent Document 1, the adjustment is made by visual observation by the operator. For this reason, variations are easily caused by the operator who performs the adjustment, and it is difficult to perform an accurate optical axis adjustment. The method disclosed in Patent Document 3 is also the same, and the tilt of the mirror is adjusted while observing the light spot of the reflected light displayed on the monitor, and the operator tends to vary.

  Moreover, in the apparatus shown in Patent Document 2, a plurality of separation mirrors and actuators attached thereto are necessary, and the apparatus becomes expensive.

  The object of the present invention is to reduce the cost of optical axis adjustment for making the optical system moving direction coincide with the optical axis direction of the laser light, particularly in an apparatus that scans and processes laser light by moving the optical system. And to be able to do it accurately.

  An optical axis adjustment method for a laser processing apparatus according to a first aspect of the present invention is a method for adjusting an optical axis of a laser beam of a laser processing apparatus having a laser oscillator and an optical system movable within a predetermined range. Including a step and a second step. The first step is a step of installing an optical axis adjusting jig in which a pinhole having a diameter smaller than the beam diameter of the laser beam is formed in the optical path of the laser beam. In the second step, the output of the laser beam that has passed through the pinhole of the jig is detected by a sensor over the movement range of the optical system, and the detected value is the same and maximized in the movement range of the optical system. This is a process for adjusting the system.

  In this method, first, a jig in which a pinhole is formed is disposed in the laser beam path. The diameter of this pinhole is smaller than the laser beam diameter. For this reason, only the strongest part of the laser light can be obtained on the downstream side of the pinhole. The output of the laser beam that has passed through the pinhole is detected by a sensor. Then, the attitude of the optical system is adjusted so that the detection value by the sensor is the same and maximized over the movement range of the optical system.

  In such an optical axis adjustment method, the moving direction of the optical system and the direction of the optical axis of the laser light can be made to coincide with each other, and the desired laser beam can be stably stabilized over the moving range of the optical system, ie, the scanning range of the laser light. Can be obtained. Then, when adjusting the optical axis, the value of the laser output is detected by a sensor, and the deviation of the optical axis is digitized and objectively judged. Compared to the above, accurate optical axis adjustment with less variation can be performed. Further, since accurate adjustment can be performed manually, an actuator for adjusting the optical axis for tilting and driving the optical system becomes unnecessary.

  An optical axis adjustment method for a laser processing apparatus according to a second invention is the optical axis adjustment method according to the first invention, wherein the optical system has a moving mirror that moves along the scanning direction of the laser light, and the moving mirror is a laser oscillator. It is possible to move between the nearest point closest to and the farthest point farthest. The first step is a step of placing the jig upstream of the moving mirror in the laser beam path. The second step is an X-axis near point adjustment step that adjusts the optical system so that the laser output is highest at the near point, and an X-axis far point adjustment that adjusts the optical system so that the laser output is highest at the far point. And a process. Then, the X-axis near point adjustment step and the X-axis far point adjustment step are repeated, and when the laser output in both steps becomes the same, the second step is ended.

  Here, the moving mirror constituting the optical system is positioned at a near point, and in this state, the laser output passing through the pinhole is detected by the sensor. In addition, the moving mirror is positioned at the far point, and similarly, the laser output passing through the pinhole is detected by the sensor. The above operation is repeatedly executed, and when the laser outputs at the near point and the far point are the same and maximum, it is determined that the second step is completed, that is, the optical axis adjustment is completed.

In this case as well, as in the first invention, the optical axis deviation is expressed numerically and objectively determined. Therefore, accurate optical axis adjustment with little variation, particularly in the scanning direction of the laser light, is made with an inexpensive configuration. The optical axis adjustment method of the laser processing apparatus according to the third aspect of the invention is the optical axis adjustment method of the second aspect of the invention, wherein the X-axis near point adjustment step is the position of the optical axis of the laser light incident on the moving mirror. Is to adjust. In the X-axis far point adjustment step, the angle of the laser beam incident on the movable mirror is adjusted.

  An optical axis adjustment method for a laser processing apparatus according to a fourth aspect of the present invention is the optical axis adjustment method of the second or third aspect, wherein the optical system includes a counter mirror disposed opposite the processing target, a counter mirror, and a processing target. And a condensing lens for condensing the laser beam, and the condensing lens is movable between a near point closest to the counter mirror and a far point farthest from the counter mirror. The first step is a step of placing the jig upstream of the condenser lens in the laser light path. The second step is a Z-axis near point adjustment step that adjusts the optical system so that the laser output is highest at the near point, and a Z-axis far point adjustment that adjusts the optical system so that the laser output is highest at the far point. And a process. Then, the Z-axis near point adjustment step and the Z-axis far point adjustment step are repeated, and when the laser output in both steps becomes the same, the second step is ended.

  Here, the condenser lens constituting the optical system is positioned at a near point, and in this state, the laser output that has passed through the pinhole is detected by the sensor. Further, the counter mirror is positioned at the far point, and similarly, the laser output that has passed through the pinhole is detected by the sensor. The above operation is repeatedly executed, and when the laser outputs at the near point and the far point are the same and maximum, it is determined that the second step is completed, that is, the optical axis adjustment is completed.

  Also in this case, as in the first aspect of the invention, since the optical axis deviation is digitized and objectively determined, accurate optical axis adjustment with little variation is performed with an inexpensive configuration, particularly in the vertical axis. be able to.

  An optical axis adjustment method for a laser processing apparatus according to a fifth invention is the optical axis adjustment method according to the fourth invention, wherein the Z-axis near point adjustment step adjusts the positions of the movable mirror and the counter mirror. The Z-axis far point adjustment step adjusts the position of the optical axis of the laser light emitted from the counter mirror.

  In the present invention as described above, the moving direction of the optical system and the direction of the optical axis of the laser beam can be matched accurately and inexpensively within the scanning range of the laser beam, and the laser is always stable. Can be processed with light.

1 is a schematic configuration diagram of a laser processing apparatus in which an optical axis (X-axis) adjustment method according to an embodiment of the present invention is implemented. 1 is a schematic configuration diagram of a laser processing apparatus in which an optical axis (X-axis) adjustment method according to an embodiment of the present invention is implemented. The figure which shows arrangement | positioning of the 4th mirror box, a condensing lens, and a jig | tool in the case of performing the optical axis adjustment of a Z-axis in the said apparatus.

[Laser processing equipment]
1 and 2 are schematic configuration diagrams of a laser processing apparatus in which an optical axis adjustment method according to an embodiment of the present invention is implemented. The laser processing apparatus includes a laser oscillator 1, a portal frame 2, an optical system 3 partially supported by the portal frame 2, and a table 4 on which a workpiece to be processed is placed. Yes. Further, the laser processing apparatus is provided with a jig 5 and a laser power sensor 6 for detecting a laser output. The jig 5 is attached when the optical axis is adjusted, and is removed when the workpiece is processed.

  The laser oscillator 1 emits a laser beam. The light intensity distribution of the laser beam emitted from the laser oscillator 1 is typically a Gaussian distribution, and the light intensity is highest at the center of the cross section of the laser beam.

  The optical system 3 includes first to fourth mirror boxes 10, 11, 12, and 13 each having a reflection mirror provided therein, and a condenser lens 14 illustrated in FIG. 3. FIG. 3 shows the fourth mirror box 13 and the condenser lens 14 taken out. Each mirror box 10-13 is provided with a mirror holder (not shown), and the first to fourth reflection mirrors 10a, 11a, 12a, 13a are fixed to the mirror holder. Each mirror holder can adjust the posture of the fixed reflecting mirrors 10a to 13a by adjusting the tilt and the rotational position. Each mirror box 10-13 has an axial stage (not shown) for moving the mirror holder in a specific axial direction (any of the X, Y, and Z axial directions shown in FIGS. 1 and 2). Is provided.

  The first mirror box 10 is disposed on the side of the laser oscillator 1 and reflects the laser light emitted from the laser oscillator 1 upward. The first mirror box 10 is provided with a Y-axis stage. The second mirror box 11 reflects the laser beam from the first mirror box 10 in the horizontal direction, and is provided with a Z-axis stage. The third mirror box 12 reflects the laser light from the second mirror box 11 and changes the direction by 90 ° in the same horizontal plane. The third mirror box 12 is provided with an X-axis stage. The fourth mirror box 13 reflects the laser beam from the third mirror box 12 downward, and is provided with a Y-axis stage. The fourth mirror box 13 can reflect the laser beam from the third mirror box 12 downward, and can guide part of it to the power sensor 6 side. The condensing lens 14 condenses the laser light from the fourth mirror box 13 on the work surface.

  The third mirror box 12 and the fourth mirror box 13 are supported by a moving table 15 disposed on the top of the portal frame 2. The moving table 15 is movable in the Y-axis direction in the horizontal plane along guide rails (not shown) provided on the portal frame 2. With such a configuration, the third mirror box 12 and the fourth mirror box 13 can move within a predetermined range in the Y-axis direction together with the condenser lens 14 and the power sensor 6. That is, the third mirror box 12 and the fourth mirror box 13 are, along the Y axis, the “near point” that is the closest position to the second mirror box 11 (laser oscillator 1 side), and conversely the second mirror box. 11 and a “far point” that is the farthest away from 11.

  The condenser lens 14 is movable in a predetermined range in the vertical direction (Z-axis direction). That is, the condenser lens 14 is movable between a “near point” closest to the fourth mirror box 13 and a “far point” farthest from the fourth mirror box 13.

  Note that the table 4 on which the workpiece is placed is movable in the X-axis direction orthogonal to the Y-axis in the horizontal plane.

  The jig 5 is provided in the third mirror box 12 in order to adjust the optical axis of the X axis, for example. More specifically, the jig 5 is detachably mounted in the third mirror box 12 on the upstream side of the laser beam path of the reflection mirror 12a. The jig 5 is formed with a pinhole having a diameter smaller than the beam diameter of the laser beam. As an example, in this embodiment, the beam diameter of the laser light is 3 mm, and the diameter of the pinhole is 0.5 mm. The position where the jig 5 is arranged is changed depending on the optical axis to be adjusted.

  Here, as described above, laser light having an intensity distribution of Gaussian distribution is used as the laser light. By installing the jig 5 having a pinhole for such a laser beam, when the intensity of the laser beam having passed through the pinhole becomes the highest, the center of the laser beam coincides with the pinhole. It can be easily judged.

  The power sensor 6 is disposed adjacent to the fourth mirror box 13, for example. As described above, the reflection mirror of the fourth mirror box 13 can pass a part of the laser light from the third mirror box 12 to the power sensor 6 side. The position where the power sensor 6 is arranged is changed depending on the optical axis to be adjusted. The position is not particularly limited as long as it is a position where the laser beam that has passed through the pinhole of the jig 5 can be received.

[Optical axis adjustment method]
In this embodiment, the optical axes of the X axis and the Z axis can be adjusted. When adjusting the optical axis, a jig 5 having a pinhole is prepared.

  First, a basic concept regarding optical axis adjustment will be described.

  Optical axis adjustment is performed at a near point and a far point. At the near point, without changing the optical axis of the laser beam, the axis stage of the mirror is moved so that the intensity of the laser beam that has passed through the pinhole is maximized so that the pinhole and the center of the laser beam coincide. adjust. If the moving direction of the moving optical system (here, the third mirror box 12, the fourth mirror box 13, and the condenser lens 14) is parallel to the optical axis of the laser beam, it passes through the pin pole even at a far point. The intensity of the laser beam remains at the highest value. However, if the moving direction of the moving optical system deviates from the direction of the optical axis of the laser beam, the intensity of the laser beam that has passed through the pinhole is reduced at the far point. At this time, the mirror angle is adjusted so that the intensity of the laser beam that has passed through the pinhole is the highest at the far point.

  When the mirror angle is adjusted, the position of the laser beam at the near point changes, so the position of the optical axis of the laser at the near point is adjusted again.

  By repeating the above steps, when the mirror is adjusted to the position and posture where the intensity of the laser beam that has passed through the pin pole is the highest at both near and far points, the moving direction of the moving optical system and the laser beam The direction of the optical axis coincides.

  Hereinafter, the X axis optical axis adjustment method and the Z axis optical axis adjustment method will be specifically described.

<Optical axis adjustment of X axis>
Follow the procedure below to adjust the optical axis of the X axis.

  Step 1: As shown in FIGS. 1 and 2, the jig 5 is disposed in the third mirror box 12 on the upstream side of the laser beam path of the reflection mirror 12a. Further, the power sensor 6 is disposed adjacent to the fourth mirror box 13.

  Step 2 (X-axis near point adjustment): As shown in FIG. 1, the third mirror box 12 and the fourth mirror box 13 are moved to the near point closest to the second mirror box 11 in the moving range, and the jig 5 The laser beam passing through the pinhole is detected by the power sensor 6. Then, the optical system 3 is adjusted so that the intensity of the laser beam becomes the highest. Specifically, the Y-axis stage of the first mirror box 10 and the Z-axis stage of the second mirror box 11 are adjusted, and the positions of the reflection mirrors 10a and 11a of the boxes 10 and 11 are adjusted.

  Step 3 (X-axis far point adjustment): As shown in FIG. 2, the third mirror box 12 and the fourth mirror box 13 are moved to the far point farthest from the second mirror box 11 in the moving range, and the jig The laser beam that has passed through the pinhole 5 is detected by the power sensor 6. Then, as in step 2, the optical system 3 is adjusted so that the intensity of the laser beam is the highest. Specifically, the mirror holder of each mirror box 10-14 is adjusted, and the attitude | position of each reflection mirror 10a-14a is adjusted.

  The adjustments in steps 2 and 3 are repeatedly performed, and the optical axis adjustment of the X axis is terminated when the maximum numerical values obtained by the power sensor 6 in the X axis near point adjustment and the X axis far point adjustment become the same.

<Z-axis optical axis adjustment>
When adjusting the optical axis of the Z axis, the above procedure is performed after the optical axis adjustment of the X axis is completed.

  Step 4: As shown in FIG. 3, the jig 5 is disposed on the upstream side of the condenser lens 14 in the laser beam path. Further, the power sensor 6 is placed on the table 4 on which the work is placed.

  Step 2 (Z-axis near point adjustment): As shown in FIG. 3, the condenser lens 14 and the jig 5 are moved to the near point closest to the fourth mirror box 13 in the movement range, and the pinhole of the jig 5 is moved. The laser beam that has passed through the power sensor 6 is detected by the power sensor 6. Then, the optical system 3 is adjusted so that the intensity of the laser beam becomes the highest. Specifically, the X axis stage of the third mirror box 12 and the Y axis stage of the fourth mirror box 13 are adjusted to adjust the positions of the reflecting mirrors 12a and 13a of the boxes 12 and 13.

  Step 3 (Z-axis far point adjustment): The condensing lens 14 and the jig 5 are moved to a far point farthest from the fourth mirror box 13 in the moving range, and the laser beam that has passed through the pinhole of the jig 5 Is detected by the power sensor 6. Then, the optical system 3 is adjusted so that the intensity of the laser beam becomes the highest. Specifically, the mirror holder of each mirror box 10-14 is adjusted, and the attitude | position of each reflection mirror 10a-14a is adjusted.

  The adjustments in Step 2 and Step 3 are repeatedly performed, and when the maximum numerical value obtained by the power sensor 6 in the Z-axis near point adjustment and the Z-axis far point adjustment becomes the same, the Z-axis optical axis adjustment is finished.

[Characteristic]
(1) A stable desired laser beam can be obtained over the scanning range of the laser beam, and the processing quality by the laser beam is stabilized.

  (2) When adjusting the optical axis, the laser intensity is detected by the power sensor 6 and the deviation of the optical axis is digitized to make an objective determination. For this reason, even if the adjustment is performed manually by the operator, accurate optical axis adjustment with less variation can be performed as compared with the conventional method visually observed by the operator.

  (3) Since the optical axis can be adjusted accurately by the operator's manual operation, an actuator or the like for driving the reflection mirror is not necessary for adjusting the optical axis, and the optical axis can be adjusted with an inexpensive configuration. it can.

  (4) Since a high-intensity laser beam that has passed through the pinhole is detected and a deviation of the optical axis is detected, more accurate adjustment can be performed.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

  The arrangement of the jig in which the pinhole is formed is not limited to the above embodiment. As long as the power sensor is arranged on the downstream side of the jig, it may be arranged at any position.

DESCRIPTION OF SYMBOLS 1 Laser oscillator 3 Optical system 4 Table 5 Jig 6 Power sensor 10-13 Mirror box 10a-13a Reflection mirror 14 Condensing lens

Claims (5)

A method for adjusting an optical axis of a laser beam of a laser processing apparatus having a laser oscillator and an optical system movable within a predetermined range,
A first step of installing an optical axis adjusting jig in which a pinhole having a diameter smaller than the beam diameter of the laser beam is formed in the optical path of the laser beam;
The optical system detects the output of the laser beam that has passed through the pinhole of the jig by a sensor over the moving range of the optical system, and the detected value is the same and maximum in the moving range of the optical system. A second step of adjusting
An optical axis adjustment method for a laser processing apparatus including: The optical system has a moving mirror that moves along a scanning direction of laser light, and the moving mirror is movable between a near point closest to the laser oscillator and a far point farthest from the laser oscillator,
The first step is a step of arranging the jig on the upstream side of the moving mirror in the laser beam path,
The second step includes
An X-axis near point adjustment step of adjusting the optical system so that the laser output is highest at the near point;
An X-axis far point adjustment step of adjusting the optical system so that the laser output is highest at the far point;
The X-axis near point adjustment step and the X-axis far point adjustment step are repeated, and when the laser output in both steps becomes the same, the second step is terminated.
The optical axis adjustment method of the laser processing apparatus according to claim 1. The X-axis near point adjustment step is to adjust the position of the optical axis of the laser light incident on the moving mirror,
The X-axis far point adjustment step is to adjust the angle of the laser beam incident on the moving mirror.
The optical axis adjustment method of the laser processing apparatus of Claim 2. The optical system includes a counter mirror disposed to face a processing target, and a condensing lens that is disposed between the counter mirror and the processing target and condenses laser light. The lens is movable between a near point closest to the opposing mirror and a far point farthest;
The first step is a step of arranging the jig on the upstream side of the condenser lens in the laser beam path,
The second step includes
A Z-axis near point adjustment step of adjusting the optical system so that the laser output is highest at the near point;
A Z-axis far point adjustment step of adjusting the optical system so that the laser output is highest at the far point;
The Z axis near point adjustment step and the Z axis far point adjustment step are repeated, and when the laser output in both steps becomes the same, the second step is terminated.
The optical axis adjustment method of the laser processing apparatus of Claim 2 or 3. The Z-axis near point adjustment step adjusts the position of the movable mirror and the counter mirror,
The Z-axis far point adjustment step is to adjust the position of the optical axis of the laser light emitted from the opposing mirror.
The optical axis adjustment method of the laser processing apparatus of Claim 4.

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