JP2008030092A - Laser beam machining apparatus and detection method of workpiece position - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus capable of accurately aligning the focus of a machining laser beam with a workpiece, in a direction orthogonal to the optical axis of the machining laser beam. <P>SOLUTION: The laser beam machining apparatus 1 includes: a laser light source 3 that emits a machining laser beam for machining a workpiece 2 and a measuring laser beam which has a smaller output than the machining laser beam while emitting to the workpiece 2; a reflector plate 9 that is arranged at a position away from the focus F of the measuring laser beam in the Z direction relative to the laser light source 3 and that reflects the measuring laser beam; a transfer mechanism 10 that holds the workpiece 2 between the laser light source 3 and the reflector plate 9; and an imaging element 7 that receives the measuring laser beam reflected by the reflector plate 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a method for detecting a position of a processing object in the laser processing apparatus.

  Conventionally, a laser processing apparatus that performs fine laser processing such as removal processing with a processing laser beam on a processing target (workpiece) has been used. As this type of laser processing equipment, in addition to the processing laser light source that emits processing laser light, the processing laser light has a wavelength different from that of the processing laser light in order to align the focus of the processing laser light and the workpiece. A laser processing apparatus having a measurement laser light source that emits light is known (for example, see Patent Document 1).

  In the laser processing apparatus described in Patent Document 1, measurement laser light emitted from a measurement laser light source and reflected by a workpiece is incident on a CCD camera. Based on the result of photographing with the CCD camera, the focus of the laser beam for measurement and the work are aligned.

Japanese Patent Laid-Open No. 2005-161387

  However, in the laser processing apparatus described in Patent Document 1, since the processing laser light and the measurement laser light are emitted from different light sources, respectively, in a direction orthogonal to the optical axis of the laser light irradiated on the workpiece, It is difficult to make the focal position of the processing laser beam coincide with the focal position of the measurement laser beam. Therefore, even if the position of the focus of the laser beam for measurement and the workpiece is accurately aligned in the direction perpendicular to the optical axis of the laser beam, the position of the focus of the laser beam for processing and the workpiece is aligned. The accuracy of is reduced.

  Accordingly, an object of the present invention is to provide a laser processing apparatus capable of highly accurately aligning the focal point of a processing laser beam and a processing object in a direction orthogonal to the optical axis of the processing laser beam. There is. In addition, an object of the present invention is to provide a position of a processing target that enables high-precision alignment of the focal point of the processing laser beam and the processing target in a direction orthogonal to the optical axis of the processing laser beam. It is to provide a detection method.

  In order to solve the above-described problems, a laser processing apparatus according to the present invention includes a processing laser beam for processing a processing target and a measurement laser that irradiates the processing target and has a smaller output than the processing laser beam. The laser beam emitting means for emitting light, and the laser beam emitting means are arranged at positions away from the focal point of the measurement laser beam in the optical axis direction of the measurement laser beam, and reflect the measurement laser beam It is characterized by comprising a reflecting means, a holding means for holding the object to be processed between the laser light emitting means and the reflecting means, and an imaging means for receiving the measurement laser light reflected by the reflecting means.

  The laser processing apparatus of the present invention receives imaging laser light reflected by a holding means for holding a workpiece between a laser light emitting means and a reflecting means and a reflecting means for reflecting the measuring laser light. Means. Therefore, the measurement laser beam reflected by the reflecting means can be used to detect the end of the workpiece in the direction perpendicular to the optical axis of the measurement laser beam (optical axis orthogonal direction). Therefore, in the direction orthogonal to the optical axis, it is possible to calculate the distance between the position of the focus of the measurement laser beam detected using the measurement laser beam and the end of the workpiece. In the laser processing apparatus of the present invention, the processing laser light and the measurement laser light are emitted from a common laser light emitting means. Therefore, in the direction orthogonal to the optical axis of the processing laser light (that is, the direction orthogonal to the optical axis), the position of the focus of the processing laser light and the position of the focus of the measurement laser light can be matched. Therefore, the distance between the focal point of the processing laser beam and the end of the object to be processed can be accurately obtained from the calculated distance between the focal point of the measuring laser beam and the end of the object to be processed. As a result, in the direction orthogonal to the optical axis, it is possible to accurately align the focal point of the processing laser beam and the processing object.

  Here, it is also possible to detect the end of the workpiece in the direction orthogonal to the optical axis by using the measurement laser beam reflected by the workpiece. However, in this case, it is difficult to align the end of the workpiece and the measurement laser beam in the direction orthogonal to the optical axis, and the detection accuracy is reduced. In the present invention, since the end of the workpiece in the direction orthogonal to the optical axis is detected using the measurement laser beam reflected by the reflecting means, the end of the workpiece can be detected easily and accurately.

  In this invention, it is preferable that a reflection means is provided with the irregular reflection surface which irregularly reflects the measurement laser beam. If comprised in this way, it will become possible to detect the edge part of a process target object with an imaging means, without adjusting the inclination of a reflection means with respect to the optical axis of the laser beam for measurement accurately. Therefore, it becomes easy to detect the end of the workpiece.

  In order to solve the above problems, the present invention provides a processing laser beam and a processing laser in a method for detecting a position of a processing object in a laser processing apparatus that processes the processing object using the processing laser light. Laser light emitting means for emitting measurement laser light having a smaller output than the light, and the laser light emitting means are arranged at a position away from the focus of the measurement laser light in the optical axis direction of the measurement laser light. An arrangement step of disposing the processing object at a position out of focus in a direction orthogonal to the optical axis direction between the reflecting means for reflecting the measurement laser beam and an emission step of emitting the measurement laser beam And an end detection step for receiving the measurement laser beam reflected by the reflecting means and detecting an end in a direction orthogonal to the optical axis direction of the workpiece, and calculating a distance between the focus and the end. Position of the workpiece Characterized in that it comprises a distance calculation step of leaving.

  In the processing object position detection method of the present invention, in the edge detection step, the measurement laser beam reflected by the reflecting means is received and the edge of the machining object in the direction perpendicular to the optical axis is detected. In the distance calculation step, the distance between the focal point of the measurement laser beam and the end is calculated to detect the position of the workpiece. In the present invention, the processing laser beam is emitted from the common laser beam emitting means in the emission step. Therefore, in the direction orthogonal to the optical axis, the position of the focus of the processing laser light and the position of the focus of the measurement laser light can be matched. Therefore, from the distance between the focus of the laser beam for measurement and the end of the workpiece, the distance between the focus of the laser beam for processing and the end of the workpiece can be accurately obtained. It becomes possible to align the focal point of the processing laser beam and the processing object with high accuracy.

  In the present invention, it is preferable that an alignment step of aligning the position of the focal point in the optical axis direction and the position of the workpiece is provided before the arrangement step. If comprised in this way, it can image | photograph clearly from the edge part of a process target object by an imaging means in a light reception step. Therefore, in the edge detection step, the edge of the workpiece can be detected with higher accuracy.

  As described above, with the laser processing apparatus of the present invention, it is possible to accurately align the focal point of the processing laser beam and the processing target in the direction orthogonal to the optical axis of the processing laser beam. Become. Further, by using the processing object position detection method of the present invention, it is possible to accurately align the processing laser beam with the processing object in the direction orthogonal to the optical axis of the processing laser light. It becomes possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Schematic configuration of laser processing equipment)
FIG. 1 is a diagram schematically showing a schematic configuration of a laser processing apparatus 1 according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a state when the workpiece 2 illustrated in FIG. 1 is in a position deviated from the focus F of the measurement laser beam in the X direction.

  The laser processing apparatus 1 of this embodiment is a laser micromachining apparatus that performs microscopic laser processing such as removal processing and bonding processing on a predetermined processing target (workpiece) 2. In particular, the laser processing apparatus 1 of the present embodiment is a lightweight and small processing apparatus that can be installed on a desktop. As shown in FIG. 1, the laser processing apparatus 1 includes a processing laser beam for processing the workpiece 2 and a measurement laser beam for aligning the focal point of the processing laser beam with the workpiece 2. A laser light source 3 serving as a laser beam emitting unit that emits light, a first light receiving element 4 serving as an emitted light amount measuring unit for measuring the amount of emitted laser light emitted from the laser light source 3, and the workpiece 2 are reflected. The second light receiving element 5 and the shielding member 6 as the reflected light amount measuring means for measuring the reflected light amount of the measurement laser light and the imaging means capable of photographing the workpiece 2 using the reflected light of the measurement laser light. An imaging device 7 and an optical system 8 for forming an optical path of processing laser light and measurement laser light emitted from the laser light source 3 are provided. Further, the laser processing apparatus 1 is disposed at a position away from the work 2 with respect to the laser light source 3 in the optical axis direction of the processing laser light and the measurement laser light, and reflects the measurement laser light. And a moving mechanism 10 as a holding means for movably holding the workpiece 2, and a control unit 11 that performs various controls of the laser processing apparatus 1.

  Hereinafter, the processing laser beam and the measurement laser beam are collectively expressed as “laser beam”. In the following description, the left-right direction in FIG. 1 is referred to as the X direction, the vertical direction on the paper is referred to as the Y direction, and the up-down direction (that is, the optical axis direction of the laser light irradiated onto the workpiece 2).

  The optical system 8 is disposed between a beam expander 16 having a concave lens 14 and a convex lens 15, a first beam sampler 17 disposed between the concave lens 14 and the convex lens 15, and an image sensor 7 and the first beam sampler 17. The second beam sampler 18 and an objective lens 19 disposed between the position where the workpiece 2 is disposed and the beam expander 16 are provided.

  In the beam expander 16, the concave lens 14 is disposed on the laser light source 3 side, and the convex lens 15 is disposed on the objective lens 19 side. The beam expander 16 expands the diameter of the laser light emitted from the laser light source 3. The first beam sampler 17 transmits most of the laser light emitted from the laser light source 3 and transmitted through the concave lens 14 toward the convex lens 15 and reflects a part thereof toward the first light receiving element 4. The first beam sampler 17 reflects part of the measurement laser light reflected by the workpiece 2 and the reflection plate 9 toward the image sensor 7. The second beam sampler 18 reflects a part of the measurement laser light reflected by the first beam sampler 17 and directed toward the image sensor 7 toward the second light receiving element 5. The objective lens 19 condenses the laser light that has passed through the convex lens 15 on the workpiece 2.

  The laser light source 3 is, for example, a fiber laser, and outputs the processing laser light and the measurement laser light as described above. The output of the measurement laser beam is much smaller than the output of the processing laser beam. Further, the laser light source 3 of the present embodiment emits a processing laser beam having a stable output in order to perform appropriate processing of the workpiece 2. On the other hand, due to the characteristics of the laser light source 3, the output from the laser light source 3 of the measurement laser light whose output is much smaller than that of the processing laser light is not stable, and the output of the measurement laser light varies with time. To do. In this embodiment, the wavelength of the processing laser light and the wavelength of the measurement laser light are substantially equal, and the focal position of the processing laser light and the focal position of the measurement laser light are substantially the same.

  The 1st light receiving element 4 and the 2nd light receiving element 5 are comprised by elements, such as a photodiode and a phototransistor. The first light receiving element 4 measures the amount of light emitted from the laser light for measurement emitted from the laser light source 3 by converting the amount of received light into an electric quantity. Further, the second light receiving element 5 measures the reflected light amount of the measurement laser light reflected by the work 2 by converting the received light amount into an electric amount.

  The shielding member 6 is formed with a minute hole 6a through which the measurement laser light reflected by the second beam sampler 18 passes. In this embodiment, when the workpiece 2 (specifically, for example, the upper surface 2a of the workpiece 2 in FIG. 1) is at the position of the focal point F of the measurement laser beam, the position at which the reflected light of the workpiece 2 forms an image ( The shielding member 6 is arranged so that the in-focus position becomes the formation position of the minute hole 6a. That is, the second light receiving element 5 of the present embodiment measures the amount of reflected light of the measurement laser light reflected by the workpiece 2 using a confocal effect that removes extra reflected light that is out of focus whose output is not stable. To do.

  The image sensor 7 is an image sensor such as a CCD or a CMOS. The image sensor 7 is arranged so that the position where the reflected light of the work 2 forms an image becomes the light receiving surface of the image sensor 7 when the work 2 is at the position of the focus F of the laser beam for measurement.

  As described above, the reflecting plate 9 is disposed at a position away from the workpiece 2 in the Z direction with respect to the laser light source 3. That is, the reflecting plate 9 is disposed at a position away from the focal point F of the measuring laser beam in the Z direction with respect to the laser light source 3. Further, as shown in FIG. 2, the reflector 9 reflects the measurement laser light when the workpiece 2 is at a position deviated from the focus F of the measurement laser light in a direction orthogonal to the Z direction. As will be described later, the reflecting plate 9 is used to detect the end of the work 2 in the X and Y directions (directions orthogonal to the Z direction). The reflection plate 9 of this embodiment is formed of a ceramic member or a metal member. Further, the reflection surface (upper surface in FIG. 1) 9a of the reflection plate 9 is an irregular reflection surface (rough surface) for irregularly reflecting incident measurement laser light. That is, the reflective surface 9a is roughened.

  The moving mechanism 10 includes a holding unit 21 that holds the workpiece 2 and a drive unit 22 that drives the holding unit 21, and holds the workpiece 2 movably between the objective lens 19 and the reflection plate 9 in the Z direction. ing. The drive unit 22 drives the holding unit 21 in the three axial directions of the X, Y, and Z directions.

  The control unit 11 is connected to the laser light source 3, the first light receiving element 4, the second light receiving element 5, the imaging element 7, and the moving mechanism 10. The control unit 11 performs various controls of the laser processing apparatus 1 as described above. For example, as will be described later, the control unit 11 performs the Z direction of the focal point F of the measurement laser beam based on the emitted light amount measured by the first light receiving element 4 and the reflected light amount measured by the second light receiving element 5. The position is specified, and the moving mechanism 10 is driven to move the work 2 to the position of the focal point F.

(Principle of detection of Z direction position of focus of laser beam for measurement)
FIG. 3 is a graph showing the relationship between the position in the Z direction of the workpiece 2 shown in FIG. 1 and the amount of reflected light measured by the second light receiving element 5.

  In this embodiment, the focal point F of the measurement laser light is based on the emitted light amount of the measurement laser light measured by the first light receiving element 4 and the reflected light amount of the measurement laser light measured by the second light receiving element 5. The position in the Z direction is detected. Hereinafter, the detection principle of the Z direction position of the focus of the measurement laser beam of this embodiment will be described.

  When the output of the measurement laser light emitted from the laser light source 3 is constant, the relationship between the reflected light amount of the measurement laser light measured by the second light receiving element 5 and the Z-direction position of the workpiece 2 is As shown by a graph G shown by a solid line in FIG. That is, when the workpiece 2 is in the position of the focus F of the measurement laser beam in the Z direction, the amount of reflected light measured by the second light receiving element 5 becomes the maximum value L, and the workpiece 2 moves from the focus F to the objective lens 19 side or As the distance from the reflecting plate 9 increases, the amount of reflected light measured by the second light receiving element 5 decreases.

  Therefore, when the output of the measurement laser beam is constant, the reflected light amount of the measurement laser beam is measured by the second light receiving element 5 while moving the workpiece 2 in the Z direction by the moving mechanism 10, and the maximum point is obtained. By specifying M and measuring the Z-direction position of the workpiece 2 corresponding to the maximum point M, the Z-direction position of the focal point F of the measurement laser beam is detected.

  However, as described above, the output of the measurement laser light emitted from the laser light source 3 of this embodiment varies with time. Therefore, the relationship between the amount of reflected light measured by the second light receiving element 5 and the position of the workpiece 2 in the Z direction does not have a substantially normal distribution, and varies, for example, as shown by a graph G10 indicated by a two-dot chain line in FIG. . Therefore, if the Z-direction position of the focus F of the measurement laser beam is detected using the reflected light amount measured by the second light receiving element 5 as it is, the detection accuracy of the Z-direction position of the focus F of the measurement laser beam is lowered. .

  Therefore, in the present embodiment, a corrected light amount obtained by correcting the reflected light amount measured by the second light receiving element 5 is calculated based on the emitted light amount of the measurement laser light measured by the first light receiving element 4. That is, the first light receiving element 4 grasps the current output of the measurement laser beam, and calculates a corrected light quantity that cancels the output variation from the reflected light quantity measured by the second light receiving element 5. Then, the Z direction position of the focal point F of the measurement laser beam is detected based on the correction light quantity.

  Specifically, the relationship between the emitted light amount measured by the first light receiving element 4 and the output of the measurement laser beam (characteristics of the first light receiving element 4), and the reflected light amount measured by the second light receiving element 5 A relationship with the output of the measurement laser beam (characteristics of the second light receiving element 5) is obtained in advance, and a corrected light amount that cancels the variation in the output of the measurement laser beam is calculated from these relationships. Then, a point at which the correction light quantity is maximized is specified in relation to the Z direction position of the work 2, and the position of the work 2 in the Z direction corresponding to the maximum point is measured. The position in the Z direction is detected. In the present embodiment, the correction light amount is calculated by the control unit 11. The control unit 11 also detects the position of the focal point F of the measurement laser beam.

(Principle of detection of X and Y direction end of work)
FIG. 4 is a diagram illustrating an example of an image captured by the image sensor 7 when the measurement laser light is reflected by the reflecting plate 9 illustrated in FIG. 1.

  In this embodiment, the measurement laser light reflected by the reflecting plate 9 is used to detect the ends of the workpiece 2 in the X and Y directions. Hereinafter, the detection principle of the X and Y direction end portions of the workpiece 2 of this embodiment will be described by taking as an example the case where the X direction end portion 2b (see FIG. 2) of the rectangular parallelepiped workpiece 2 is detected.

  Before detecting the X-direction end 2b of the workpiece 2, first, the Z-direction position of the focus F of the measurement laser beam is detected by the above-described method, and the workpiece 2 and the focus F are aligned. That is, as shown in FIG. 1, the upper surface 2a of the workpiece 2 and the focal point F are aligned in the Z direction. In this state, a focus corresponding point F1 corresponding to the focus F is set on the video imaged by the image sensor 7 (see FIG. 4). Thereafter, as shown in FIG. 2, the workpiece 2 is moved in the X direction by the moving mechanism 10 and is disposed at a position out of the focal point F in the X direction.

  When the work 2 deviates from the focus F in the X direction, for example, an image shown in FIG. That is, a part of the measurement laser light irregularly reflected by the reflecting plate 9 is blocked by the work 2, so that the work corresponding area 21 corresponding to the work 2 on the image taken by the image sensor 7 becomes dark, The area becomes brighter. Further, since the upper surface 2a of the work 2 and the focal point F are aligned in the Z direction, the end corresponding line 211 corresponding to the X direction end 2b of the work 2 was photographed by the image sensor 7. It is clearly identified on the video. That is, the X direction end 2b of the workpiece 2 is detected. In order to detect the X-direction end 2b of the work 2 with higher accuracy, it is preferable to dispose a magnifying optical system in front of the image sensor 7.

  When the end corresponding line 211 is clearly specified, a distance X1 in the X direction between the end corresponding line 211 and the focus corresponding point F1 is calculated. That is, the distance between the X direction end 2b and the focal point F is calculated. Further, since the distance between the X-direction end 2b and the machining part of the workpiece 2 is known in advance in design, the distance in the X direction from the focal point F to the machining part of the workpiece 2 is calculated. Similarly, the end of the workpiece 2 in the Y direction is also detected, and the distance in the Y direction from the focal point F to the machining site of the workpiece 2 is calculated. Further, the calculation of the distance from the focal point F to the processing part of the workpiece 2 is performed by the control unit 11.

(Work positioning method)
FIG. 5 is a flowchart showing a procedure for aligning the workpiece 2 in the laser processing apparatus 1 shown in FIG. In the laser processing apparatus 1 configured as described above, the workpiece 2 is aligned as follows.

  First, the workpiece 2 is moved in the X and Y directions by the moving mechanism 10, and the workpiece 2 is arranged at a position where the laser beam emitted from the laser light source 3 is irradiated (step S1). Thereafter, measurement laser light is emitted from the laser light source 3 (step S2), the emitted light quantity is measured by the first light receiving element 4, and the reflected light quantity is measured by the second light receiving element 5 (step S3).

  Thereafter, a corrected light amount is calculated and stored from the emitted light amount measured by the first light receiving element 4 and the reflected light amount measured by the second light receiving element 5 (step S4). Thereafter, the work 2 is arranged in a predetermined range in the Z direction, and it is determined whether or not the emitted light quantity and the reflected light quantity are measured at each arrangement position (step S5). Specifically, in step S5, it is determined whether or not the work 2 is arranged in a predetermined range including the position of the focal point F of the measurement laser beam in the Z direction and the emitted light quantity and reflected light quantity are measured at each arrangement position. To do. When the measurement is not performed within the predetermined range, the process returns to step S3.

  On the other hand, when the emitted light quantity and the reflected light quantity are measured within a predetermined range, the Z-direction position of the focus F of the measurement laser beam is detected from the corrected light quantity calculated and stored in step S4 (step S7). Specifically, an approximate curve is created from the correction light quantity corresponding to each position of the work 2, the point where the correction light quantity is maximized in relation to the Z direction position of the work 2 is specified, and the position of the focus F in the Z direction Is detected.

  When the Z direction position of the focus F of the measurement laser beam is detected, the moving mechanism 10 moves the work 2 in the Z direction, and the detected focus F and the work 2 are aligned in the Z direction (step S8). . Thereafter, the workpiece 2 is moved in the X and Y directions by the moving mechanism 10, and the workpiece 2 is arranged at a position out of the focal point F in the X and Y directions (step S9). In this state, the edge of the workpiece 2 is detected by the image sensor 7 using the reflected light from the reflecting plate 9 (step S10). Thereafter, the distance between the end portion of the workpiece 2 and the focal point F is calculated, and the distance between the processed part of the workpiece 2 and the focal point F is calculated, and the position of the workpiece 2 with respect to the focal point F is detected (step S11). Then, the processing mechanism and the focus F are aligned in the X and Y directions by the moving mechanism 10 (step S12), and the alignment of the workpiece 2 is completed. Further, after the workpiece 2 is aligned, a laser beam for processing is emitted from the laser light source 3 to perform laser processing on the workpiece 2.

  In this embodiment, step S9 is a step of placing a workpiece between the laser light source 3 and the reflector 9 in the X and Y directions at a position deviating from the focus F, and step S2 is for measurement. This is an emission step for emitting laser light, and step S10 is an edge detection step in which the imaging element 7 receives the measurement laser light reflected by the reflecting plate 9 and detects the edges in the X and Y directions. Step S11 is a distance calculation step for detecting the position of the workpiece 2 by calculating the distance between the end portion of the workpiece 2 and the focal point F. In the present embodiment, steps S3 to S8 are alignment steps in which the position of the focal point F and the position of the work 2 in the Z direction are aligned before step S9, which is an arrangement step.

(Main effects of this form)
As described above, in the present embodiment, the measurement laser light reflected by the reflecting plate 9 is received by the image sensor 7 and the ends of the workpiece 2 in the X and Y directions are detected. Further, the distance between the focus F of the measurement laser beam and the end of the work 2 is calculated, and the position of the work 2 with respect to the focus F is detected. In this embodiment, the processing laser light and the measurement laser light having substantially the same wavelength are emitted from the common laser light source 3. For this reason, the focal point of the processing laser beam and the focal point F of the measuring laser beam substantially coincide. That is, the focal point of the processing laser beam and the focal point F of the measuring laser beam substantially coincide with each other in the X and Y directions. Therefore, the distance between the focal point of the processing laser beam and the end of the workpiece 2 can be obtained with high precision from the distance between the focal point F of the measuring laser beam and the end of the workpiece 2, and machining can be performed in the X and Y directions. It becomes possible to align the focal point of the laser beam for use with the workpiece 2 with high accuracy.

  In particular, in the present embodiment, after the position of the focus F of the measurement laser light in the Z direction and the position of the work 2 are aligned, the work 2 is reflected using the measurement laser light reflected by the reflecting plate 9. The ends in the X and Y directions are detected. Therefore, the image pickup device 7 can capture a clear image from the end portion of the work 2, and as a result, the end portion of the work 2 can be detected with higher accuracy.

  In this embodiment, the reflection surface 9a of the reflection plate 9 is an irregular reflection surface that irregularly reflects the measurement laser beam. Therefore, the end of the workpiece 2 can be easily detected by the image sensor 7 without adjusting the inclination of the reflecting plate 9 with respect to the optical axis of the measurement laser light with high accuracy.

(Other embodiments)
In the embodiment described above, the reflected light amount of the measurement laser light reflected by the workpiece 2 is measured by the second light receiving element 5, but the reflected light amount of the measurement laser light may be measured by the image sensor 7. . Further, the amount of reflected laser light for measurement may be measured by both the second light receiving element 5 and the image sensor 7. Here, as shown by the solid line in FIG. 6, the reflected light incident on the image sensor 7 is brightest at the center of the reflected light and gradually becomes darker as the distance from the center increases. Then, in the reflected light image captured by the image sensor 7, an area having a brightness equal to or higher than a predetermined threshold t is specified as a spot of the reflected light, and the total brightness of the specified spots is measured by the image sensor 7. The amount of reflected laser light for measurement is reflected. Similarly to the case where the reflected light amount is measured by the second light receiving element 5, the reflected light amount of the measurement laser beam is measured by the imaging element 7 while the workpiece 2 is moved in the Z direction by the moving mechanism 10, and the workpiece is measured. The position of the focal point F of the measurement laser beam can be detected by specifying the maximum point of the reflected light quantity in relation to the position of 2 in the Z direction.

  Also in this case, when the output of the measurement laser light varies with time, even if the position of the workpiece 2 in the Z direction is constant, the amount of reflected light measured by the image sensor 7 varies. For example, as indicated by a two-dot chain line in FIG. 6, when the output of the measurement laser light is reduced, the brightness of the reflected light incident on the image sensor 7 is also reduced, resulting in a smaller spot, and as a result, the reflected reflection measured. The amount of light also decreases. Therefore, similarly to the above-described embodiment, the focus F of the measurement laser beam is corrected by correcting the reflected light amount measured by the imaging device 7 in consideration of the variation of the emitted light amount from the measurement result of the first light receiving element 4. Can be detected with high accuracy.

  In the case where the amount of reflected light is measured using only the image sensor 7, the second light receiving element 5, the shielding member 6, and the second beam sampler 18 are not required as shown in FIG. Can be simplified. Further, as shown in FIG. 7, the laser processing apparatus 1 does not necessarily include the first light receiving element 4. That is, even in the laser processing apparatus 1 that does not include the first light receiving element 4, it is possible to accurately align the focal point of the processing laser beam and the workpiece 2 in the X and Y directions.

  In the embodiment described above, the reflection surface 9a of the reflection plate 9 is a diffuse reflection surface. In addition, for example, the reflecting surface 9a may be a mirror surface. In this case, the inclination of the reflecting surface 9a may be adjusted so that the end corresponding line 211 appears on the video imaged by the image sensor 7.

  Note that the output of the processing laser light is very large and the first light receiving element 4 may be destroyed by the processing laser light reflected by the first beam sampler 17, or is reflected by the workpiece 2 or the like. When there is a possibility that the second light receiving element 5 or the image pickup element 7 may be destroyed by the processing laser light, the space between the first beam sampler 17 and the first light receiving element 4, or between the first beam sampler 17 and the first light receiving element 4. A shutter, a light reducing film, or a beam sampler for the purpose of light reduction is preferably disposed between the two beam sampler 18.

The figure which shows typically schematic structure of the laser processing apparatus of embodiment of this invention. The figure which shows a state when the workpiece | work shown in FIG. 1 exists in the position which remove | deviated from the focus of the laser beam for a measurement in a X direction. The graph which shows the relationship between the position of the Z direction of the workpiece | work shown in FIG. 1, and the reflected light quantity measured with a 2nd light receiving element. The figure which shows an example of the image | video image | photographed with an image pick-up element, when the measurement laser beam is reflected by the reflecting plate shown in FIG. The flowchart which shows the procedure of the position alignment of the workpiece | work in the laser processing apparatus shown in FIG. The figure which shows the relationship between the brightness from the center of the reflected light and the reflected light reflected by the workpiece | work shown in FIG. The figure which shows typically schematic structure of the laser processing apparatus concerning the other form of this invention.

Explanation of symbols

1 Laser processing equipment 2 Workpiece (object to be processed)
3 Laser light source (Laser light emitting means)
7 Image sensor (imaging means)
9 Reflector (reflecting means)
9a Reflecting surface (diffuse reflecting surface)
10 Movement mechanism (holding means)
F focus S2 emission step S3 to S8 alignment step S9 placement step S10 edge detection step S11 distance calculation step

Claims (4)

  Laser beam emitting means for emitting a processing laser beam for processing a workpiece and a measurement laser beam that is irradiated onto the workpiece and has a smaller output than the processing laser beam, and the laser beam Reflecting means for reflecting the measurement laser light, disposed at a position away from the focus of the measurement laser light in the optical axis direction of the measurement laser light with respect to the emission means, and the laser light emission means, A laser processing apparatus comprising: a holding unit that holds the object to be processed with the reflecting unit; and an imaging unit that receives the measurement laser light reflected by the reflecting unit.   The laser processing apparatus according to claim 1, wherein the reflection unit includes an irregular reflection surface that irregularly reflects the measurement laser beam. In a method for detecting a position of a processing object in a laser processing apparatus that processes the processing object using a processing laser beam,
Laser light emitting means for emitting the processing laser light and measurement laser light having a smaller output than the processing laser light, and the measurement in the optical axis direction of the measurement laser light with respect to the laser light emitting means The processing object is disposed at a position away from the focal point of the laser beam for measurement and is reflected from the reflection means for reflecting the measurement laser beam and at a position off the focus in a direction perpendicular to the optical axis direction. A placement step for placing objects;
An emission step of emitting the measurement laser beam;
An end detection step of receiving the measurement laser beam reflected by the reflection means and detecting an end of the workpiece in a direction orthogonal to the optical axis direction;
A distance detection step of calculating a distance between the focal point and the end portion, and detecting a position of the processing object.   The position of the processing object according to claim 3, further comprising an alignment step of aligning the position of the focal point in the optical axis direction and the position of the processing object before the arranging step. Detection method.

Images