Laser processing device and method for checking a processing mark

Abstract

This invention provides a laser processing apparatus and a method for identifying processing marks, wherein the laser processing apparatus automatically determines the boundaries of regions where processing marks are formed. The laser processing apparatus includes: a laser beam irradiation unit that irradiates a laser beam having a wavelength absorbed by a workpiece; an imaging unit; and a processing unit that processes the image acquired by the imaging unit. The processing unit includes: a histogram generation unit that generates a first histogram including multiple first positions along a first direction of the image and the brightness at each first position, and a second histogram including multiple second positions along a second direction perpendicular to the first direction and the brightness at each second position, based on an image obtained from multiple processing marks formed by irradiating one side of the workpiece with a laser beam from the laser beam irradiation unit; and a determination unit that determines the boundaries of regions where each processing mark is formed based on the first histogram and the second histogram.

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus for forming multiple processing marks by irradiating one side of a workpiece with a laser beam, and a method for identifying the area where each processing mark exists. Background Technology

[0002] In laser processing apparatuses that process workpieces by irradiating them with a laser beam of a wavelength absorbed by the workpiece, the shape of the laser beam affects the processing quality. For example, the shape of the laser beam is confirmed by observing the processing results after the workpiece has been actually processed using the laser beam.

[0003] In one example, when processing one side of a flat workpiece using a laser beam in a linear fashion, the other side, located opposite to one side of the workpiece, is first held by a holding stage provided in the laser processing apparatus. Then, the holding stage is moved in a predetermined direction substantially perpendicular to the irradiation direction of the laser beam, and the workpiece is processed in a linear fashion using the laser beam (see, for example, Patent Document 1).

[0004] During processing, the height of the focusing lens that converges the laser beam is positioned at multiple different heights, forming multiple linear processing marks corresponding to each height. For example, positioning the focusing lens at the first height forms the first linear processing mark.

[0005] Next, a condenser lens is positioned at a second height, different from the first height, and a laser beam is irradiated onto an area different from the first machining mark, forming a linear second machining mark. After multiple linear machining marks are formed on one side of the workpiece, the shape of the laser beam is confirmed by observing the width of each machining mark.

[0006] In addition, sometimes the shape of the laser beam is confirmed by forming multiple dot-shaped machining marks on the upper surface of the workpiece. In this case, an image of the upper surface with multiple dot-shaped machining marks is first acquired. Then, based on the image, the contour of the machining marks is detected, and the conformity of the laser beam shape is determined.

[0007] However, when contour inspection and acceptance / disapproval are performed manually, the processing time is substantial. Furthermore, the criteria for determining the boundaries between processed and unprocessed areas, as well as the criteria for acceptance / disapproval, may change due to operator error. Therefore, automating these processing tasks using laser processing equipment is being considered.

[0008] For example, consider having the operator first specify the coordinates of the boundaries of multiple small regions each containing a machining mark, and then performing image processing on each small region to automatically detect the contour of the machining mark.

[0009] Patent Document 1: Japanese Patent Application Publication No. 2013-78785

[0010] However, there is a problem: the coordinates of the boundary need to be specified every time the position of the machining mark is changed, so only operators with professional knowledge can perform the operation, and the operation takes time. Summary of the Invention

[0011] The present invention was made in view of this problem, and its purpose is to automatically determine the boundaries of the areas with processing marks formed in the image by means of a laser processing device, without requiring the operator to specify the coordinates of the boundaries of multiple small areas.

[0012] According to one aspect of the present invention, a laser processing apparatus is provided, comprising: a laser beam irradiation unit that irradiates a laser beam having a wavelength absorbed by the workpiece to process the workpiece; an imaging unit for imaging the workpiece; and a processing unit that processes an image acquired by the imaging unit of the workpiece, the processing unit comprising: a histogram generation unit that generates an image based on an image obtained by the imaging unit of a plurality of processing marks formed by irradiating a laser beam from the laser beam irradiation unit to one side of the workpiece, the image comprising a first histogram including a plurality of first positions along a first direction and the brightness at each first position, and a second histogram including a plurality of second positions along a second direction perpendicular to the first direction and the brightness at each second position; and a determination unit that determines the boundary of the region where each processing mark is formed based on the first histogram and the second histogram generated by the histogram generation unit.

[0013] Preferably, the histogram generation unit accumulates values ​​representing the brightness scale of multiple pixels located on a straight line passing through the first position and parallel to the second direction at each first position to generate the first histogram, and accumulates values ​​representing the brightness scale of multiple pixels located on a straight line passing through the second position and parallel to the first direction at each second position to generate the second histogram.

[0014] In addition, the processing unit preferably includes a contour detection unit, which generates a third histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the second direction and parallel to the first direction, and a fourth histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the first direction and parallel to the second direction, thereby detecting the contour of the machining mark.

[0015] According to another aspect of the present invention, a method for confirming machining marks is provided, which, after forming a plurality of machining marks by irradiating a workpiece with a laser beam using a laser processing apparatus, is used to confirm the area where each machining mark is formed. The method comprises the following steps: a machining mark forming step, in which the workpiece is irradiated with the laser beam having a wavelength absorbed by the workpiece to form the plurality of machining marks on the workpiece; an imaging step, in which the plurality of machining marks formed by the machining mark forming step are imaged to acquire an image; a histogram generating step, in which a processing unit of the laser processing apparatus generates a first histogram of the image including a plurality of first positions along a first direction and the brightness at each first position, and a second histogram of the image including a plurality of second positions along a second direction perpendicular to the first direction and the brightness at each second position; and a determination step, in which the processing unit determines the boundary of the area where each machining mark is formed based on the first histogram and the second histogram generated by the histogram generating step.

[0016] Preferably, in the histogram creation step, the processing unit accumulates values ​​representing the brightness scale of multiple pixels located on a straight line passing through the first position and parallel to the second direction at each first position to create the first histogram, and accumulates values ​​representing the brightness scale of multiple pixels located on a straight line passing through the second position and parallel to the first direction at each second position to create the second histogram.

[0017] In addition, the preferred method for confirming the machining marks also includes the following contour detection step: for the region, the processing unit generates a third histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the second direction and parallel to the first direction, and a fourth histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the first direction and parallel to the second direction, thereby detecting the contour of each machining mark.

[0018] One aspect of the laser processing apparatus of the present invention includes a processing unit for processing an image containing multiple processing marks. The processing unit includes a histogram generation unit. The histogram generation unit generates a first histogram of the image containing a plurality of first positions along a first direction and the brightness at each first position, and a second histogram containing a plurality of second positions along a second direction perpendicular to the first direction and the brightness at each second position.

[0019] The processing unit also includes a determining unit. The determining unit determines the boundaries of the regions where multiple processing marks exist based on a brightness histogram generated by the histogram generating unit. Therefore, the laser processing apparatus can automatically determine the boundaries of the regions where processing marks are formed. Attached Figure Description

[0020] Figure 1 It is a 3D diagram of a laser processing device.

[0021] Figure 2 It is a schematic diagram of an image containing multiple machining marks.

[0022] Figure 3 This is a flowchart of the method of the first embodiment.

[0023] Figure 4 (A) is a diagram illustrating the steps involved in creating a histogram. Figure 4 (B) is a diagram illustrating the steps involved in determining the steps.

[0024] Figure 5 This diagram illustrates the contour detection steps.

[0025] Figure 6 This is a diagram illustrating the histogram creation and determination steps of the second embodiment.

[0026] Label Explanation

[0027] 2: Laser processing device; 4: Base; 10: Y-axis moving unit; 20: X-axis moving unit; 30: Worktable base; 32: Chuck worktable; 32a: Holding surface; 32b: Fixture; 40: Support; 42: Z-axis moving unit; 44: Z-axis pulse motor; 46: Z-axis moving plate; 48: Support; 50: Laser beam irradiation unit; 52: Housing; 54: Condenser; 56: Camera unit (image capturing unit) 58: Input / output device; 60: Control unit; 62: Processing unit; 64: Histogram generation unit; 66: Determination unit; 68: Contour detection unit; 70: Image; 72: First position; 74: Second position; 11: Workpiece; 11a: One surface; 11b: Another surface; 13: Protective belt; 15: Frame; 17: Workpiece unit; A, A1, A2, A3, A4, A5, A6, A7, A8, A9, A 10 A 11 A 12 A 13 A 14 A 15 A 16 A 17 A 18 A 19 A 20 A 21 B1: Machining marks; B2: First histogram; B3: Second histogram; B4: Machining marks. 3-1 B 3-2 B 3-3 : 3rd histogram; B4, B 4-1 B 4-2 B 4-3B5: Histogram 4; B6: Histogram 5; B7: Histogram 6; C: Value; D: Histogram 6 X1 D X2 D X3 D X4 D Y1 D Y2 D Y3 D Y4 E: Line; F: Small area (region); F, F1, F2, F3, G, G1, G2, G3, H1, H2: Line. Detailed Implementation

[0028] An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a 3D view of laser processing device 2. Additionally, in Figure 1 In the diagram, some of the components of the laser processing device 2 are shown using functional blocks.

[0029] in addition, Figure 1 The X-axis direction (left-right direction, machining feed direction, first direction), Y-axis direction (front-back direction, indexing feed direction, second direction), and Z-axis direction (vertical direction, height direction) shown are perpendicular to each other.

[0030] The laser processing apparatus 2 has a cuboid base 4 that supports the various components. A Y-axis moving unit 10 is provided on the upper surface of the base 4. The Y-axis moving unit 10 has a pair of Y-axis guide rails 12 parallel to the Y-axis direction.

[0031] A pair of Y-axis guide rails 12 are fixed to the upper surface of the base 4. The Y-axis movable worktable 14 is slidably mounted on the pair of Y-axis guide rails 12. A nut portion (not shown) is provided on the back side (lower surface side) of the Y-axis movable worktable 14.

[0032] A Y-axis ball screw 16, arranged parallel to the Y-axis guide rail 12, is rotatably attached to the nut portion. Furthermore, a Y-axis pulse motor 18 is connected to one end of the Y-axis ball screw 16.

[0033] If the Y-axis ball screw 16 is rotated by the Y-axis pulse motor 18, the Y-axis moving table 14 moves along the Y-axis guide rail 12 in the Y-axis direction. An X-axis moving unit 20 is provided on the upper surface of the Y-axis moving table 14.

[0034] The X-axis moving unit 20 has a pair of X-axis guide rails 22 parallel to the X-axis direction. The pair of X-axis guide rails 22 are fixed to the upper surface of the Y-axis moving stage 14. The X-axis moving stage 24 is slidably mounted on the pair of X-axis guide rails 22.

[0035] A nut portion (not shown) is provided on the lower surface of the X-axis moving worktable 24, and an X-axis ball screw 26, which is arranged parallel to the X-axis guide rail 22, is rotatably connected to the nut portion. An X-axis pulse motor 28 is connected to one end of the X-axis ball screw 26.

[0036] If the X-axis ball screw 26 is rotated by the X-axis pulse motor 28, the X-axis moving table 24 moves along the X-axis guide rail 22 in the X-axis direction. A cylindrical table base 30 is fixed to the upper surface of the X-axis moving table 24.

[0037] A roughly disc-shaped chuck worktable 32 is provided on the upper part of the worktable base 30. A rotary drive source such as an electric motor (not shown) is connected to the chuck worktable 32 and is provided inside the worktable base 30.

[0038] The chuck table 32 can rotate about a rotation axis that is approximately parallel to the Z-axis direction, driven by a rotational drive source. The chuck table 32 has a metal frame. A recess (not shown) consisting of a disk-shaped space is formed on the upper side of the frame.

[0039] One end of a flow path (not shown) for attracting gas or the like is connected to the recess. Additionally, an attraction source (not shown) such as an injector is connected to the other end of the flow path. A disc-shaped porous plate (not shown) is fixed to the recess of the frame.

[0040] When the suction source is activated, a negative pressure is generated on the upper surface (holding surface 32a) of the porous plate. The workpiece 11 is placed on the holding surface 32a. The workpiece 11 is formed, for example, from silicon and has a disk shape comprising a generally flat surface 11a and another surface 11b.

[0041] Furthermore, the material of the workpiece 11 is not limited to silicon, and the workpiece 11 can be formed from other materials. In addition, the workpiece 11 can also be a stacked substrate in which multiple substrates (such as silicon substrates and sapphire substrates) formed of different materials are bonded together.

[0042] A resin protective tape 13 with a diameter larger than that of the workpiece 11 is adhered to the other side 11b of the workpiece 11. The protective tape 13 has, for example, a laminated structure of a substrate layer and an adhesive layer, which is adhered to the other side 11b of the workpiece 11.

[0043] A metal ring-shaped frame 15 with an opening having a diameter larger than the outer diameter of the workpiece 11 is attached to the outer periphery of the protective belt 13. This forms a workpiece unit 17 in which the workpiece 11 is supported by the frame 15 via the protective belt 13. The workpiece 11 is conveyed and processed within the workpiece unit 17.

[0044] Multiple clamps 32b are provided on the side of the frame of the chuck worktable 32. After the workpiece unit 17 is placed on the holding surface 32a with one surface 11a on top and the other surface 11b on the bottom, the frame 15 is clamped by each clamp 32b.

[0045] A quadrangular prism-shaped support portion 40 is fixed on the upper surface of the base 4 near one (rear) end in the Y-axis direction. A Z-axis moving unit 42 is provided on one side of the support portion 40 in the X-axis direction.

[0046] The Z-axis moving unit 42 has a pair of Z-axis guide rails that are approximately parallel to the Z-axis direction. Each Z-axis guide rail is fixed to one side of the support 40. The Z-axis moving plate 46 is slidably mounted on each Z-axis guide rail.

[0047] A nut portion (not shown) is provided on the back side (i.e. the support portion 40 side) of the Z-axis moving plate 46, and a Z-axis ball screw (not shown) arranged parallel to the Z-axis guide rail is rotatably connected to the nut portion.

[0048] A Z-axis pulse motor 44 is connected to one end of the Z-axis ball screw. If the Z-axis ball screw is rotated by the Z-axis pulse motor 44, the Z-axis moving plate 46 moves along the Z-axis guide rail in the Z-axis direction.

[0049] A support 48 is fixed on the front side (opposite to the back side) of the Z-axis moving plate 46. A cylindrical cavity with its height direction parallel to the Y-axis direction is formed on the support 48. A cylindrical housing 52 is fixed in this cavity. The housing 52 constitutes the laser beam irradiation unit 50.

[0050] The laser beam irradiation unit 50 includes a laser oscillator (not shown) that generates a pulsed laser beam by laser oscillation. The laser oscillator may have, for example, a rod-shaped laser medium formed of Nd:YAG or Nd:YVO4.

[0051] The laser beam emitted from the laser oscillator passes through a laser beam adjustment unit (not shown), optical components such as a reflector, and is incident on a concentrator 54 located at the other (front) end of the housing 52 in the Y-axis direction. A concentrating lens (not shown) is provided inside the concentrator 54 to focus the laser beam.

[0052] The optical axis of the condenser lens is configured to be approximately parallel to the Z-axis direction, and the laser beam emitted from the condenser lens irradiates the holding surface 32a approximately perpendicularly. In one example, the laser beam has a wavelength absorbed by the workpiece 11 (e.g., a wavelength of 355 nm), a repetition frequency of 20 kHz to 50 kHz, and an average output of 3.0 W to 6.0 W.

[0053] A camera unit (imaging unit) 56 is disposed on the other side (right) of the housing 52 along the X-axis. The camera unit 56 is, for example, a visible light camera, which has an objective lens (not shown) and an imaging element (not shown) that receives visible light from the subject via the objective lens. The imaging element is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor.

[0054] The base 4 is covered by a cover (not shown), and an input / output device 58 is provided on the side of the front side of the cover. The input / output device 58 is, for example, a touch panel. The input / output device 58 serves as both an input unit for the operator to input processing conditions, etc., and a display unit for displaying processing conditions or images, etc.

[0055] The laser processing apparatus 2 includes a control unit 60 that controls each of its constituent elements. The control unit 60 controls the operation of the Y-axis moving unit 10, the X-axis moving unit 20, the rotation drive source, the attraction source, the Z-axis moving unit 42, and the laser beam irradiation unit 50.

[0056] The control unit 60 is, for example, a computer, which includes a processing device such as a CPU (Central Processing Unit), a main storage device such as DRAM (Dynamic Random Access Memory), and auxiliary storage devices such as flash memory and hard disk drives. The processing device and the like are operated according to software stored in the auxiliary storage devices, thereby realizing the function of the control unit 60.

[0057] The control unit 60 includes a processing unit 62 that processes images captured by the camera unit 56. The processing unit 62 may be software, such as a program that is read and executed by the aforementioned processing device. Furthermore, the processing unit 62 is not limited to software; it may also be hardware such as an application-specific integrated circuit (ASIC).

[0058] The processing unit 62 includes a histogram generation unit 64. The histogram generation unit 64 generates a histogram that uses the position of each pixel arranged along a predetermined direction among the multiple pixels constituting the image as the horizontal axis and the brightness of the pixel as the vertical axis.

[0059] For example, the histogram production unit 64 produces a first histogram that uses the position in the X-axis direction (first direction) as the horizontal axis and the cumulative value of the scale representing the brightness of multiple pixels arranged in a column along the Y-axis direction as the vertical axis.

[0060] In addition, the histogram production unit 64 produces a second histogram that uses the position in the Y-axis direction (second direction) as the horizontal axis and the cumulative value of the scale representing the brightness of multiple pixels arranged in a column along the X-axis direction as the vertical axis.

[0061] The processing unit 62 also includes a determination unit 66, which determines the approximate range of each processing mark that is discretely present in the image. For example, if the processing mark is brighter than the background of the image, the determination unit 66 determines the location where the cumulative brightness value is lower in the first histogram and the second histogram.

[0062] Next, the determining unit 66 sets an imaginary straight line that passes through the X-axis direction where the cumulative value is lower and is parallel to the Y-axis direction, and an imaginary straight line that passes through the Y-axis direction where the cumulative value is lower and is parallel to the X-axis direction, thereby dividing the image.

[0063] The processing unit 62 also includes a contour detection unit 68, which detects the contour of the machining mark for a small area divided by the determination unit 66. In this embodiment, the contour detection unit 68 generates a third histogram representing the brightness of a plurality of pixels arranged in a column along the X-axis and a fourth histogram representing the brightness of a plurality of pixels arranged in a column along the Y-axis for a small area, thereby detecting the contour of the machining mark.

[0064] Next, a machining mark A is formed on one surface 11a of the workpiece 11 using the laser processing apparatus 2 (see reference). Figure 2 Furthermore, the method for identifying the area where processing marks A are formed is explained. Figure 3 This is a flowchart of the method of the first embodiment.

[0065] In this method, a machining mark formation step S10 is performed first. In the machining mark formation step S10, after the workpiece 11 is held on the chuck table 32 with one surface 11a exposed upwards, a pulsed laser beam is irradiated onto one surface 11a to process the workpiece 11.

[0066] In this embodiment, after a machining mark A is formed on one side of surface 11a, irradiation is temporarily stopped. Furthermore, the chuck stage 32 is moved relative to the condenser 54 in at least any direction in the X-axis and Y-axis directions to change the irradiation position of the laser beam.

[0067] After changing the irradiation position, another machining mark A was formed on one side of surface 11a. Thus, 21 machining marks A were formed at different locations on one side of surface 11a. Figure 2 The machining marks A1 to A shown 21 ).

[0068] Furthermore, in this embodiment, when changing the irradiation position, the height of the focusing lens of the focusing device 54 is set at different heights. Specifically, in the machining mark A1, the focusing point of the laser beam is positioned inside the workpiece 11.

[0069] In addition, each time the irradiation position is changed, the focal point is moved upwards in stages, thereby sequentially forming machining marks A2, A3, A4…A 10 Next, in the process of forming machining mark A... 11 At that time, the focusing point is positioned at a point where the processing mark A is formed. 10 Laser processing is performed on a surface 11a at a position near the top of the focal point.

[0070] Then, similarly, each time the irradiation position is changed, the focal point is moved upwards in stages, thereby sequentially forming processing marks A. 12 A 13 A 14 …A 21 That is, in the formation of machining mark A 12 …A 21 At that time, the spotlight is positioned above one of the surfaces 11a.

[0071] After the machining mark formation step S10, the imaging step S20 is performed. In the imaging step S20, the camera unit 56 is used to capture an image 70 containing all the formed machining marks A.

[0072] Figure 2 This is a schematic diagram of an image 70 containing multiple processing marks A. In this embodiment, the processing marks A are displayed as brighter than the background in image 70. Furthermore, image 70 can be a multi-valued image displayed using grayscale levels or full color, or a binary image displayed using black and white.

[0073] After the image capture step S20, the histogram creation step S30 is performed. In the histogram creation step S30, the histogram creation unit 64 creates a representation of multiple first positions 72 arranged along the X-axis direction based on the image 70 (see reference). Figure 4 The first histogram B1 of the brightness at (A)).

[0074] The first histogram B1 of this embodiment is created by accumulating the values ​​of a scale representing the brightness of a plurality of pixels located on a straight line passing through the first position 72 and parallel to the Y-axis direction at each first position 72. Figure 4 Figure (A) illustrates step S30 of the histogram creation process. Additionally, Figure 4 The quantity of position 72 shown in (A) is an example, and it can be more than that quantity.

[0075] Figure 4 The horizontal axis of the graph shown below (A) is the X-axis, and the vertical axis of the graph represents brightness. In this embodiment, each processing mark A is displayed as brighter than the area where no processing mark A is formed. Therefore, in the straight line passing through the first position 72 and parallel to the Y-axis direction, the more pixels located at the processing mark A, the higher the value of the brightness scale.

[0076] The histogram generation unit 64 also generates a second histogram B2 based on the image 70, representing the brightness at multiple second positions 74 along the Y-axis direction. Additionally, Figure 4 Taking the number of 74 in position 2 shown in (A) as an example, it can be more than that number.

[0077] The second histogram B2 of this embodiment is created by accumulating the values ​​of the scale representing the brightness of a plurality of pixels located on a straight line passing through the second position 74 and parallel to the X-axis direction at each second position 74. Figure 4 The horizontal axis of the curve shown on the left side of (A) is the Y-axis, and the vertical axis of the curve represents brightness.

[0078] After the histogram creation step S30, the determination unit 66 determines the boundaries of the regions in the image 70 where discrete processing marks A are formed, based on the created first histogram B1 and second histogram B2 (determination step S40).

[0079] In this embodiment, the determining unit 66 determines the first position 72 in the first histogram B1 where the brightness is a low value C, such as a minimum or extreme value. Figure 4 (X1, X2, X3, and X4 shown in (B)). Furthermore, multiple imaginary straight lines D (which become the first position 72 of value C and are parallel to the Y-axis direction) are used. Figure 4 D shown in (B) X1 D X2 D X3 and D X4 The image 70 is divided into segments.

[0080] Similarly, the determining unit 66 determines the second position 74 in the second histogram B2 where the brightness is a low value C such as a minimum or extreme value. Figure 4 (Y1, Y2, Y3, and Y4 shown in (B)). Furthermore, multiple imaginary straight lines D (which become the second position 74 of value C and are parallel to the X-axis direction) are used. Figure 4 D shown in (B) Y1 D Y2 D Y3 and D Y4 The image 70 is divided into segments.

[0081] Figure 4(B) is a diagram illustrating step S40. Figure 4 The curve shown below (B) has its horizontal axis as the X-axis and its vertical axis as brightness. Additionally, in Figure 4 The horizontal axis of the curve shown on the left side of (B) is the Y-axis, and the vertical axis of the curve represents brightness.

[0082] exist Figure 4 In the example shown in (B), the value C is common in both the first histogram B1 and the second histogram B2. Additionally, through multiple lines D... X1 D X2 D X3 and D X4 and multiple straight lines D Y1 D Y2 D Y3 and D Y4 The image 70 is divided into a grid pattern, forming multiple small regions E.

[0083] There is a high probability that a machining mark A exists within each small region E. In this embodiment, the laser processing apparatus 2 can automatically determine the boundaries of the regions where each machining mark A is formed. That is, it automatically determines the small region E containing the machining mark A.

[0084] Therefore, there is no need to reassign the coordinates corresponding to the boundary of the small region E every time the position of the machining mark A is changed. In addition, the laser processing apparatus 2 automatically determines the boundary of the small region E, so that even operators without professional knowledge can perform the operation.

[0085] Furthermore, in histogram B1, the peak between X2 and X3 is lower than the other peaks. Conversely, in histogram B2, the peak between Y2 and Y3 is higher than the other peaks.

[0086] Therefore, based on the difference in peaks, the processing unit 62 can determine that, between X2 and X3, there is only a processing mark A in a small region E surrounded by the four points (X2, Y2), (X2, Y3), (X3, Y2), and (X3, Y3).

[0087] After determining step S40, the contour detection unit 68 detects the contour of each machining mark A (contour detection step S50). Figure 5 This diagram illustrates the contour detection step S50. Additionally, in Figure 5 The diagram shows a schematic of the outline of a machining mark A.

[0088] The contour detection unit 68 generates a third histogram B3 and a fourth histogram B4 for each small region E. The third histogram B3 represents the brightness of multiple pixels on each of the multiple straight lines F located at different positions in the Y-axis direction and parallel to the X-axis direction.

[0089] exist Figure 5 The diagram illustrates three third histograms B representing the brightness of multiple pixels along three straight lines F1, F2, and F3. 3-1 B 3-2 and B 3-3 The horizontal axis of each third histogram (B3) is the X-axis, and the vertical axis is the brightness.

[0090] Histogram B4 (number 4) represents the brightness of multiple pixels on each of the multiple straight lines G located at different positions along the X-axis and parallel to the Y-axis. Figure 5 The example shows three fourth histograms B representing the brightness of multiple pixels on three straight lines G1, G2, and G3. 4-1 B 4-2 and B 4-3 The horizontal axis of each fourth histogram (B4) is the Y-axis, and the vertical axis represents brightness.

[0091] The rising positions (i.e., X and Y coordinates) of the third histogram B3 and the fourth histogram B4 correspond to the edge of the machining mark A. The contour of the machining mark A is determined by connecting the rising positions. Alternatively, the contour detection unit 68 can use methods such as edge detection to determine the contour of the machining mark A.

[0092] Next, the second embodiment will be described. In the second embodiment, in the histogram creation step S30, the histogram creation unit 64 does not accumulate the values ​​of the scale representing the brightness of multiple pixels. Furthermore, in the determination step S40, the determination unit 66 does not use minimum values, but instead uses peaks, rising points, etc., to determine the boundaries. This differs from the first embodiment.

[0093] Figure 6 This diagram illustrates the histogram creation step S30 and the determination step S40 of the second embodiment. The histogram creation unit 64 of the second embodiment creates a fifth histogram B5 representing the X-coordinate (horizontal axis) and brightness (vertical axis) on a straight line H1 along the X-axis direction. The fifth histogram B5 is a histogram at the straight line H1, which is located at the third position in the Y-axis direction and passes through five machining marks A arranged side-by-side along the X-axis direction.

[0094] Next, if there are multiple peaks, rising parts (edges), etc. in the fifth histogram B5, the determination unit 66 takes the middle position of two adjacent peaks or the middle position of an adjacent edge sandwiched between valleys as the boundary of the small region E.

[0095] Furthermore, if there are no peaks in the fifth histogram B5, the histogram creation unit 64 moves the straight line H1 in the Y-axis direction and repeats the creation of the fifth histogram B5 until peaks are obtained.

[0096] Similarly, the histogram generation unit 64 generates a sixth histogram B6 representing the Y-coordinate (horizontal axis) and pixel brightness (vertical axis) on a straight line H2 along the Y-axis direction. The sixth histogram B6 is a histogram at the straight line H2, which is located at the first position in the X-axis direction and passes through five machining marks A arranged side by side along the Y-axis direction.

[0097] Next, if there are multiple peaks, rising parts (edges), etc. in the sixth histogram B6, the determination unit 66 takes the middle position of two adjacent peaks or the middle position of an adjacent edge sandwiched between valleys as the boundary of the small region E.

[0098] Furthermore, if there are no peaks in the sixth histogram B6, the histogram creation unit 64 moves the straight line H2 in the X-axis direction and repeats the creation of the sixth histogram B6 until peaks are obtained.

[0099] The structure and method of the above embodiments can be appropriately modified and implemented as long as they do not depart from the scope of the present invention. For example, after the contour detection step S50, the processing unit 62 may calculate the area of ​​the region where each processing mark A is formed, the centroid of each processing mark A, and the offset of each processing mark A relative to the perfect circle. As a result, the shape of the laser beam and the state of the laser processing apparatus 2 can be diagnosed.

[0100] Furthermore, in the above embodiment, an example was described where the machining mark A is displayed brighter than the background in image 70, but the machining mark A can also be displayed darker than the background in image 70. In this case, the brightness and darkness are reversed in each histogram, so the processing content of the processing unit 62 is appropriately adjusted according to the first or second embodiment.

[0101] In addition, the method for confirming the machining mark A described above may be performed, for example, before laser lift-off processing of the workpiece 11 using the laser processing apparatus 2 and during trial processing of the workpiece 11.

Claims

1. A laser processing apparatus, characterized in that, This laser processing device has the following features: A laser beam irradiation unit processes a workpiece by irradiating it with a laser beam having a wavelength that is absorbed by the workpiece. A camera unit, used to photograph the workpiece; and The processing unit processes the images acquired by photographing the workpiece using the imaging unit. The processing unit has: The histogram generation unit generates an image based on an image obtained by taking pictures of multiple processing marks formed by irradiating a laser beam from the laser beam irradiation unit onto one side of the workpiece using the imaging unit. The image generates a first histogram containing multiple first positions along a first direction and the brightness at each first position, and a second histogram containing multiple second positions along a second direction perpendicular to the first direction and the brightness at each second position. as well as The determining unit determines the first position and the second position where the brightness becomes a common minimum value in the first histogram and the second histogram produced by the histogram making unit, respectively, and divides the image into a grid pattern using multiple imaginary straight lines that pass through the first position where the brightness becomes the minimum value and are parallel to the second direction, and multiple imaginary straight lines that pass through the second position where the brightness becomes the minimum value and are parallel to the first direction, thereby determining the boundaries of the areas where each processing mark is formed.

2. The laser processing apparatus according to claim 1, characterized in that, The histogram generation unit generates the first histogram by accumulating the values ​​of a scale representing the brightness of multiple pixels located on a straight line passing through the first position and parallel to the second direction at each first position. The second histogram is created by accumulating the values ​​of the scale representing the brightness of multiple pixels located on a straight line passing through the second position and parallel to the first direction at each second position.

3. The laser processing apparatus according to claim 1 or 2, characterized in that, The processing unit also includes a contour detection unit, which generates a third histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the second direction and parallel to the first direction, and a fourth histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the first direction and parallel to the second direction, thereby detecting the contour of the machining mark.

4. A method for identifying machining marks, comprising identifying the areas with each machining mark after irradiating one side of a workpiece with a laser beam using a laser processing device to form multiple machining marks, characterized in that, The method for confirming machining marks involves the following steps: The machining mark forming step involves irradiating the workpiece with a laser beam having a wavelength absorbed by the workpiece to form the plurality of machining marks on one side of the workpiece. The imaging step involves capturing images of the multiple machining marks formed through the machining mark formation step. The histogram creation step involves the processing unit of the laser processing apparatus creating a first histogram of the image, comprising a plurality of first positions along a first direction and the brightness at each first position, and a second histogram of a plurality of second positions along a second direction perpendicular to the first direction and the brightness at each second position; and In the determination step, the processing part determines the first position and the second position where the brightness becomes a common minimum value in the first histogram and the second histogram created by the histogram creation step, and divides the image into a grid pattern using multiple imaginary straight lines that are parallel to the second direction at the first position where the brightness becomes the minimum value and multiple imaginary straight lines that are parallel to the first direction at the second position where the brightness becomes the minimum value, thereby determining the boundaries of the areas where each processing mark is formed.

5. The method for confirming machining marks according to claim 4, characterized in that, In the steps of creating this histogram, The processing unit accumulates the values ​​of a scale representing the brightness of multiple pixels located on a straight line passing through the first position and parallel to the second direction at each first position to create the first histogram. The second histogram is created by accumulating the values ​​of the scale representing the brightness of multiple pixels on a straight line passing through the second position and parallel to the first direction at each second position.

6. The method for confirming machining marks according to claim 4 or 5, characterized in that, The method for confirming machining marks also includes the following contour detection step: For the region, the processing unit generates a third histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the second direction and parallel to the first direction, and a fourth histogram representing the brightness of multiple pixels on each of multiple straight lines located at different positions in the first direction and parallel to the second direction, thereby detecting the contour of each machining mark.

Images