Alignment mark detection device and laser processing device

Abstract

To provide an alignment mark detection device capable of improving a processing speed of work by surely detecting an alignment mark.SOLUTION: An alignment mark detection device includes: a ring-shaped illumination device in which a plurality of arcuate illuminations each having an arcuate shape are arranged in a circumferential direction; an imaging device that images an alignment mark; an image processing device that performs image processing on a captured image; and a position detection device that detects a position of the alignment mark based on the captured image subjected to the image processing. The imaging device acquires a captured image each time illumination light is emitted by one arcuate illumination. The image processing device generates a combined image by combining a plurality of captured images captured at the time of irradiation of different arcuate illuminations. The position detection device detects a position of the alignment mark based on the combined image.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an alignment mark detection device and a laser processing device that detect an alignment mark used to align a laser irradiation position when performing hole drilling by irradiating a laser. [Background technology]

[0002] A laser processing device that irradiates a printed circuit board with a laser to drill holes has been known. The laser processing device detects alignment marks formed on the printed circuit board, and irradiates the printed circuit board with a laser at a pre-registered irradiation position based on the position of the detected alignment mark.

[0003] For example, as described in Patent Document 1, a laser processing device detects the center position of an alignment mark by capturing an image of a printed circuit board while irradiating the alignment mark with illumination light from a ring-shaped illumination device from around the alignment mark. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-21164 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the laser processing device described in Patent Document 1 irradiates the alignment mark with illumination light from all directions, 360° around the alignment mark, which can result in an image with unclear contours. Even if image processing is performed based on an image with unclear contours, the center position of the alignment mark cannot be detected. In this case, the operator must manually input the center position of the alignment mark, which slows down the processing speed.

[0006] An object of the present invention is to provide an alignment mark detection device that can reliably detect alignment marks and improve the processing speed of work. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the alignment mark detection device of the present invention is an alignment mark detection device that detects an alignment mark on a substrate, and is equipped with a ring-shaped illumination device in which multiple arc-shaped arc lights are arranged circumferentially, an imaging device that images the alignment mark illuminated by the illumination device, an image processing device that performs image processing on the image of the alignment mark imaged by the imaging device, and a position detection device that detects the position of the alignment mark based on the image processed by the image processing device, wherein the imaging device acquires an image each time illumination light is irradiated onto the alignment mark by one arc light, the image processing device performs image processing to generate a combined image that combines the multiple image images captured when irradiated by different arc lights, and the position detection device detects the position of the alignment mark based on the combined image. [Effects of the Invention]

[0008] According to the present invention, in an alignment mark detection device, it is possible to reliably detect alignment marks and improve the processing speed of work. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a laser processing device according to an embodiment. [Figure 2] 1 is a schematic diagram of an alignment mark detection apparatus according to an embodiment. [Figure 3] FIG. 2 is a plan view of the lighting device as seen from the bottom side (printed circuit board side). [Figure 4] 10A and 10B are explanatory diagrams of captured images of alignment marks captured by an imaging device. [Figure 5]FIG. 10 is an explanatory diagram for explaining imaging of an alignment mark. [Figure 6] FIG. 10 is an explanatory diagram of a combined image generated by the image processing device. [Figure 7] 10 is a flowchart illustrating a process for detecting the position of an alignment mark. [Figure 8] FIG. 10 is an explanatory diagram for explaining imaging of an alignment mark in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Configuration of laser processing equipment] As shown in Fig. 1, the laser processing apparatus 1 according to the present invention includes a laser oscillator 2, an optical path system 3, a first galvanometer scanner 4A, a second galvanometer scanner 4B, an fθ lens 5, an XY table 6, an imaging device 7, an image processing device 8, a control device 9, and an illumination device 13. The control device 9 controls the overall operation of the laser processing apparatus 1 and is realized by, for example, a program-controlled processor. The control device 9 includes a "position detection device" in the claims.

[0011] The laser oscillator 2 outputs a laser beam under the control of the control device 9. The laser beam output from the laser oscillator 2 passes through the optical path system 3 and is incident on the mirror 41 of the first galvanometer scanner 4A. When the mirror 41 is in a neutral position, it reflects the laser beam incident from the right direction in the figure toward the front direction in the figure. The orientation of the mirror 41 is changed under the control of the control device 9. As a result, the mirror 41 can change the path of the laser beam within the horizontal plane in the figure, that is, in the left-right direction (Y-axis direction) in the figure at its position on the XY table 6.

[0012] The laser beam reflected by mirror 41 is incident on mirror 42 of second galvanometer scanner 4B. When mirror 42 is in a neutral position, it reflects a laser beam incident from the back in the figure downward in the figure. The orientation of mirror 42 is changed under the control of control device 9. This allows mirror 42 to change the path of the laser beam in the front-to-back direction in the figure (X-axis direction). The Y-axis direction is perpendicular to the X-axis direction.

[0013] The laser beam reflected by the mirror 42 is irradiated via the fθ lens 5 onto the printed circuit board 10 placed on the XY table 6. The XY table 6 is driven in the X-axis direction and the Y-axis direction by an X-axis drive mechanism and a Y-axis drive mechanism (not shown), respectively, and can move and position the placed printed circuit board 10 in the X and Y directions.

[0014] The illumination device 13 irradiates the printed circuit board 10 on the XY table 6 with illumination light under the control of the control device 9. This allows the imaging device 7 to capture an image of the printed circuit board 10. Images of the printed circuit board 10 and the alignment marks 11 captured by the imaging device 7 will be described later.

[0015] An alignment mark 11 is formed in advance on the printed circuit board 10. In this embodiment, the alignment mark 11 has a convex shape that is convex relative to the printed circuit board 10. The imaging device 7 captures an image of the alignment mark 11 illuminated by the illumination device 13. The image processing device 8 performs image processing on the captured image of the alignment mark 11 captured by the imaging device 7. The control device 9 detects the position of the alignment mark 11 from the captured image of the alignment mark 11 that has been subjected to image processing by the image processing device 8. The shape of the alignment mark 11 is not particularly limited, and may be, for example, a circle (a perfect circle) when viewed in a plane.

[0016] The control device 9 operates the XY table 6 based on the position of the detected alignment mark 11 to position the printed circuit board 10 in the X and Y directions. After the printed circuit board 10 placed on the XY table 6 has been positioned in the X and Y directions, the control device 9 controls the laser oscillator 2 to align the path of the laser beam with a pre-registered irradiation position and irradiate the printed circuit board 10 with the laser beam. In this way, the laser processing device 1 performs a drilling process to open a hole 12 in the printed circuit board 10.

[0017] [Configuration of alignment mark detection device] 2, among the components of the laser processing apparatus 1 described above, the imaging device 7, image processing device 8, control device 9, and illumination device 13 constitute an alignment mark detection device 15 according to the present invention. The alignment mark detection device 15 detects alignment marks 11 on a printed circuit board 10. The alignment mark detection device 15 is disposed at a predetermined distance from the printed circuit board 10 in the Z-axis direction (thickness direction of the printed circuit board 10) in the drawing. [Configuration of imaging device] 2, the imaging device 7 is, for example, a CCD camera, and includes a lens 21 and an imaging element (not shown). In the imaging device 7, the lens 21 forms an image of a subject on the imaging element, which then captures the subject image. The imaging device 7 (more specifically, the lens 21) is disposed inside a ring-shaped illumination device 13, which will be described later. The imaging optical axis CL1 of the lens 21 is disposed parallel to the vertical direction (Z-axis direction) in the figure. The Z-axis direction is perpendicular to the X-axis direction and the Y-axis direction.

[0018] [Lighting equipment configuration] 3, the illumination device 13 is a ring-shaped illumination device. The illumination device 13 is arranged so as to surround the imaging device 7 (more specifically, the lens 21). The illumination device 13 has a plurality of arc-shaped arc illuminators arranged in the circumferential direction R. In this embodiment, the illumination device 13 has four arc illuminators 13A to 13D, each having a central angle of 90°, arranged in the circumferential direction R. The circumferential direction R is a circumferential direction centered on the imaging optical axis CL1 of the lens 21.

[0019] The number of arc lights aligned in the circumferential direction in lighting device 13 is not limited to four, but may be two, three, or five or more. Whatever the number, lighting device 13 is preferably configured with arc lights that have the same central angle equally divided around the circumference.

[0020] Each of the arc illuminators 13A to 13D is made up of a plurality of illumination light sources 31 arranged along the circumferential direction R. The plurality of illumination light sources 31 are provided on the bottom surface side of the support member 32. The plurality of illumination light sources 31 are arranged along the circumferential direction R at equal angular intervals.

[0021] In this embodiment, the lighting device 13 has 36 illumination light sources 31 on each of three concentric circles, for a total of 108 illumination light sources 31, and the illumination light sources 31 are arranged at equal angular intervals of 10° in the circumferential direction. The illumination light sources 31 are, for example, LEDs (light-emitting diodes). Note that, although the illumination light sources 31 are arranged in three concentric circles in this embodiment, the present invention is not limited to this, and the illumination light sources 31 may be arranged in one or two rows, or in four or more concentric rows.

[0022] All of the arc illuminators 13A to 13D have the same number of illumination light sources 31. In the example shown in Fig. 3, all of the arc illuminators 13A to 13D have 27 illumination light sources 31. As described above, the illumination device 13 is configured by connecting a plurality of arc illuminators, each of which has an arc shape, in the circumferential direction R. Therefore, when the imaging device 7 images the alignment mark 11, the illumination device 13 irradiates the alignment mark 11 with illumination light from the periphery thereof.

[0023] The control device 9 controls each of the first to fourth arc-shaped illuminators 13A to 13D of the illumination device 13 to emit illumination light for each arc-shaped illuminator. The imaging device 7 captures an image each time the alignment mark 11 is irradiated with illumination light by one arc-shaped illuminator.

[0024] 4(A) to 4(D), imaging device 7 acquires four captured images 51 to 54 for one alignment mark 11. This is because illumination device 13 is equipped with four arc illuminators 13A to 13D, and imaging device 7 captures an image each time illumination light from one arc illuminator is irradiated onto alignment mark 11, thereby acquiring a total of four captured images 51 to 54.

[0025] Fig. 4(A) shows a first captured image 51 captured by the imaging device 7 when illumination light from the first arc illumination light 13A is irradiated onto the alignment mark 11. In Figs. 4(A) to 4(D), imaging areas 55A to 55D indicate areas obtained by dividing the first to fourth captured images 51 to 54 into four, respectively.

[0026] Note that imaging area 55A is an imaging area corresponding to first arc-shaped illuminant 13A, and is an area that overlaps with first arc-shaped illuminant 13A when viewed from a direction parallel to imaging optical axis CL1. Similarly, imaging areas 55B to 55D are areas corresponding to arc-shaped illuminants 13B to 13D, respectively, and are areas that overlap with arc-shaped illuminants 13B to 13D, respectively, when viewed from a direction parallel to imaging optical axis CL1.

[0027] 5, when capturing the first captured image 51, the control device 9 causes the first arc-shaped illumination light 13A to irradiate the alignment mark 11. As described above, the alignment mark 11 has a convex shape that is convex with respect to the printed circuit board 10, and therefore a shadow 56A is formed on the opposite side of the illumination light from the first arc-shaped illumination light 13A.

[0028] The shadow 56A is formed at a position on the opposite side of the first arc-shaped illuminant 13A with respect to the imaging optical axis CL1. That is, in the first captured image 51, the shadow 56A is located in an imaging region 55C located on the opposite side of the imaging region 55A corresponding to the first arc-shaped illuminant 13A (see FIG. 4A).

[0029] 4(B) shows a second captured image 52 captured by the imaging device 7 when illumination light from the second arc-shaped illumination light 13B is irradiated onto the alignment mark 11. As in the case where illumination light is irradiated from the first arc-shaped illumination light 13A, a shadow 56B is formed at a position on the opposite side of the imaging optical axis CL1 from the second arc-shaped illumination light 13B. That is, in the second captured image 52, the shadow 56B is located in an imaging region 55D located on the opposite side of the imaging region 55B corresponding to the second arc-shaped illumination light 13B.

[0030] 4(C) shows a third captured image 53 captured by the imaging device 7 when illumination light from the third arc-shaped illumination light 13C is irradiated onto the alignment mark 11. As in the case where illumination light is irradiated from the first and second arc-shaped illumination lights 13A and 13B, a shadow 56C is formed at a position on the opposite side of the imaging optical axis CL1 from the third arc-shaped illumination light 13C. That is, in the third captured image 53, the shadow 56C is located in the imaging region 55A located on the opposite side of the imaging region 55C corresponding to the third arc-shaped illumination light 13C.

[0031] 4(D) shows a fourth captured image 54 captured by the imaging device 7 when illumination light from the fourth arc-shaped illumination light 13D is irradiated onto the alignment mark 11. As in the case when illumination light is irradiated from the first to third arc-shaped illumination lights 13A to 13C, a shadow 56D is formed at a position on the opposite side of the imaging optical axis CL1 from the fourth arc-shaped illumination light 13D. That is, in the fourth captured image 54, the shadow 56D is located in the imaging region 55B located on the opposite side of the imaging region 55D corresponding to the fourth arc-shaped illumination light 13D.

[0032] [Configuration of image processing device] The image processing device 8 performs image processing on a plurality of captured images acquired by the imaging device 7 when irradiated with different arc-shaped illuminations. In this embodiment, the image processing device 8 performs image processing on four captured images 51 to 54 captured by the imaging device 7 by illuminating one alignment mark 11 with each of a plurality of arc-shaped illuminations 33A to 33D.

[0033] The image processing device 8 cuts out an imaging region capturing an image of a position on the opposite side of the arc-shaped illumination 13A that irradiates the illumination light with respect to the imaging optical axis CL1 from the captured image. That is, when the image processing device 8 processes the first captured image 51, it cuts out an imaging region 55C capturing an image of a position on the opposite side of the first arc-shaped illumination 13A that irradiates the illumination light with respect to the imaging optical axis CL1 from the first captured image 51.

[0034] When the image processing device 8 processes the second captured image 52, an imaging region 55D capturing an image of a position opposite to the second arc-shaped illumination 13B that irradiates the illumination light with respect to the imaging optical axis CL1 is cut out from the second captured image 52.

[0035] When the image processing device 8 processes the third captured image 53, an imaging region 55A capturing an image of a position opposite to the third arc illuminator 13C that irradiates the illumination light with respect to the imaging optical axis CL1 is cut out from the third captured image 53.

[0036] When the image processing device 8 processes the fourth captured image 54, an imaging region 55B capturing an image of a position opposite to the fourth arc illuminator 13D that irradiates the illumination light with respect to the imaging optical axis CL1 is cut out from the fourth captured image 54.

[0037] As described above, the shadow 56A is located in the imaging area 55C in the first captured image 51. Similarly, the imaging area 55D in the second captured image 52, the imaging area 55A in the third captured image 53, and the imaging area 55B in the fourth captured image 54 are located in the imaging areas 55B to 56D, respectively.

[0038] As described above, the image processing device 8 cuts out the imaging areas from all of the captured images taken by the imaging device 7 for one alignment mark 11, and then generates one combined image from the captured images with these cut-out imaging areas.

[0039] 6, the combined image 57 is generated from captured images obtained by cutting out an imaging region capturing an image of a position on the opposite side of the arc illumination irradiated with illumination light with respect to the imaging optical axis CL1. That is, in this embodiment, the combined image 57 is generated from an imaging region 55C in the first captured image 51, an imaging region 55D in the second captured image 52, an imaging region 55A in the third captured image 53, and an imaging region 55B in the fourth captured image 54. The control device 9 detects the position of the alignment mark 11 based on the combined image 57 generated by the image processing device 8.

[0040] [Process to detect the position of the alignment mark] 7 is a flowchart of a process for detecting the position of an alignment mark by the laser processing apparatus 1 and alignment mark detection device 15 of this embodiment. The control device 9 first aligns the position of the imaging optical axis CL1 with the position of the alignment mark 11 (S1). The alignment in this case does not need to be performed strictly; for example, it is sufficient for an operator to simply operate the X-axis drive mechanism and Y-axis drive mechanism of the XY table 6 to move the printed circuit board 10 in the X and Y directions, and then align the position of the imaging optical axis CL1 with the position of the alignment mark 11 by checking the image captured by the imaging device 7.

[0041] After aligning the imaging optical axis CL1, the control device 9 controls the illumination device 13 to irradiate the alignment mark 11 with illumination light from the first arc-shaped illumination device 13A (S2). Next, while maintaining the state in which illumination light is irradiated from the first arc-shaped illumination device 13A, the control device 9 controls the imaging device 7 to acquire the first captured image 51 (S3).

[0042] After acquiring the first captured image 51, the control device 9 performs the following processes: irradiating the alignment mark 11 with illumination light using the second arc illuminator 13B (S4), acquiring a second captured image (S5), irradiating the alignment mark 11 with illumination light using the third arc illuminator 13C (S6), acquiring a third captured image (S7), irradiating the alignment mark 11 with illumination light using the fourth arc illuminator 13D (S8), and acquiring a fourth captured image (S9), thereby acquiring first to fourth captured images 51 to 54 for one alignment mark 11.

[0043] After acquiring all of the first to fourth captured images 51 to 54, the control device 9 performs image processing on the first to fourth captured images 51 to 54 to generate a combined image 57 (S10). As described above, the combined image 57 is generated from the imaging area 55C in the first captured image 51, the imaging area 55D in the second captured image 52, the imaging area 55A in the third captured image 53, and the imaging area 55B in the fourth captured image 54. These are the imaging areas in which the shadows 56A to 56D are located, respectively.

[0044] The control device 9 detects the position of the alignment mark 11 based on the combined image 57 generated by the image processing device 8 from the first to fourth captured images 51 to 54 (S11). As described above, the combined image 57 is generated by combining the captured areas in which the shadows 56A to 56D are formed, and therefore the outline of the alignment mark 11 is clear. The control device 9 can detect the center position of the alignment mark 11 from the outline of the alignment mark 11.

[0045] As described above, the laser processing device 1 can reliably detect the alignment mark 11. Furthermore, since the alignment mark 11 can be reliably detected, the operator does not need to manually input the position of the alignment mark, and the laser irradiation position can be easily determined, thereby improving the processing speed of the work.

[0046] [Example when the alignment mark is concave] In the above embodiment, the alignment marks 11 formed on the printed circuit board 10 have a convex shape that is convex relative to the printed circuit board 10, but as in another example shown in Fig. 8, the alignment marks 11 may also have a concave shape that is concave relative to the printed circuit board 10. The configuration of the laser processing device 1 is the same as in the first embodiment, and the same reference numerals are used and the description thereof will be omitted.

[0047] In this example, as in the above embodiment, the control device 9 controls the first to fourth arc-shaped illuminators 13A to 13D of the illumination device 13, respectively, to emit illumination light from each arc-shaped illuminator. The imaging device 7 acquires first to fourth captured images 51 to 54 each time illumination light from one arc-shaped illuminator is emitted onto the alignment mark 11. Note that Fig. 8 is a diagram showing a state in which illumination light is emitted from the first arc-shaped illuminator 13A onto the alignment mark 11 when capturing the first captured image 51.

[0048] As described above, in this embodiment, the alignment mark 11 has a concave shape that is recessed with respect to the printed circuit board 10, and therefore the shadow 58A is formed at a position corresponding to the first arc-shaped illumination light 13A with respect to the imaging optical axis CL1. That is, in the first captured image 51, the shadow 58A is located in the imaging region 55A that corresponds to the first arc-shaped illumination light 13A.

[0049] When capturing the second to fourth captured images 52 to 54, the shadow of the alignment mark 11 is also formed at a position corresponding to the arc-shaped illumination. In this embodiment, the image processing device 8 cuts out from the captured images an imaging region corresponding to the arc-shaped illumination irradiated with illumination light, with respect to the imaging optical axis CL1. In this way, the imaging regions cut out from the captured images by the image processing device 8, i.e., imaging region 55A in the first captured image 51, imaging region 55B in the second captured image 52, imaging region 55C in the third captured image 53, and imaging region 55D in the fourth captured image 54, are imaging regions in which the shadows are located.

[0050] The image processing device 8 generates a combined image from the first to fourth captured images 51 to 54, similar to the above embodiment. As described above, the combined image is generated from the imaging area 55A in the first captured image 51, the imaging area 55B in the second captured image 52, the imaging area 55C in the third captured image 53, and the imaging area 55D in the fourth captured image 54. The control device 9 detects the position of the alignment mark 11 based on the combined image, similar to the above embodiment. Since the combined image is generated by combining imaging areas in which a shadow is formed, the outline of the alignment mark 11 is clear. Therefore, the same effect as the above embodiment can be obtained.

[0051] Furthermore, the present invention can be applied to devices for detecting alignment marks other than laser processing devices. The above-described embodiments are examples for explaining the present invention, and are not intended to limit the scope of the present invention to only these embodiments. Those skilled in the art can make appropriate modifications within the scope of the present invention. [Explanation of symbols]

[0052] 1. Laser processing equipment 2 Laser oscillator 3 Optical path system 4A First Galvanometer Scanner 4B Second Galvanometer Scanner 5 fθ lenses5 6 XY table 7. Imaging device 8 Image Processing Device 9 Control Device 10 Printed circuit board 11 Alignment marks 12 holes 13 Lighting equipment 13A~13D Arc lighting 21 Lens 31 Lighting source 32 Support member 41, 42 Mirror 56A~56D, 58A shadow 57 Combined Images CL1 Imaging optical axis R circumferential direction

Claims

1. An alignment mark detection device for detecting alignment marks on a printed circuit board, a ring-shaped lighting device in which a plurality of arc-shaped lighting units are arranged in a circumferential direction; an imaging device that images the alignment mark illuminated by the illumination device; an image processing device that performs image processing on the captured image of the alignment mark captured by the imaging device; a position detection device that detects the position of the alignment mark based on the captured image that has been subjected to the image processing by the image processing device; Equipped with the imaging device acquires the captured image each time illumination light from one of the arcuate illuminations is irradiated onto the alignment mark; the image processing device performs the image processing to generate a combined image by combining a plurality of the captured images captured when irradiated with different arcuate illuminations, The alignment mark detecting device is characterized in that the position detecting device detects the position of the alignment mark based on the combined image.

2. the alignment mark has a convex shape that is convex with respect to the printed circuit board, The alignment mark detection device according to claim 1, characterized in that the image processing device generates the combined image by cutting out from the captured image an imaging area that captures an image of a position on the opposite side of the arc illumination that irradiates the illumination light with respect to the imaging optical axis of the imaging device.

3. the alignment mark has a concave shape that is recessed relative to the printed circuit board, The alignment mark detection device according to claim 1, characterized in that the image processing device generates the combined image by cutting out from the captured image an imaging area corresponding to the arc illumination irradiated with illumination light relative to the imaging optical axis of the imaging device.

4. 2. The alignment mark detection device according to claim 1, wherein the plurality of arcuate illuminations are formed by equally dividing the circumference of the ring-shaped illumination device.

5. The plurality of arc illuminators all have the same number of illumination light sources, 5. The alignment mark detection device according to claim 4, wherein the illumination light sources are arranged at equal angular intervals in the circumferential direction.

6. An alignment mark detection device according to any one of claims 1 to 5; a drive mechanism that moves the printed circuit board based on the position of the alignment mark detected by the alignment mark detection device; a laser oscillator that irradiates the printed circuit board positioned by the drive mechanism with a laser beam aligning its path with a pre-registered irradiation position, thereby drilling holes in the printed circuit board.

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