Laser processing device

Abstract

To provide a laser processing device that enables rapid formation of lines on a film-like workpiece conveyed between two rolls while realizing miniaturization of the device.SOLUTION: A laser processing device 1 includes: a conveying unit that conveys a film-like workpiece 60 from a first roll 11 to a second roll 12; a processing head 20 that radiates a laser beam onto a processing object surface 60a of the workpiece 60; a head transfer mechanism 40 that moves the processing head 20 in a width direction of the workpiece 60; a camera 31 that is disposed on the upstream side in a conveying direction of the workpiece 60 relative to the processing head 20; and a control unit that controls the conveying unit, the processing head 20, and the head transfer mechanism 40. The control unit moves the processing head 20 such that a distance between an irradiation position P11 of the laser beam on the processing object surface 60a and a reference line extending along the conveying direction on the workpiece 60 is maintained at a predetermined target distance while the workpiece 60 is continuously conveyed from the first roll 11 to the second roll 12.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus that forms groove-shaped lines on a surface to be processed using laser light.

Background Art

[0002] Conventionally, a laser processing apparatus that forms groove-shaped lines on a surface to be processed using laser light is known. For example, in the manufacturing process of a monocrystalline integrated structure solar cell, lines are formed on a transparent conductive layer, a power generation / absorption layer, and a conductive layer laminated on a substrate. In this manufacturing process, a film-shaped workpiece wound around a first roll is fed out from the first roll and wound up by a second roll. While the workpiece is being conveyed from the first roll to the second roll, the workpiece is temporarily stopped, and a line is formed on the surface to be processed by the laser processing apparatus.

[0003] Patent Document 1 below describes a laser processing apparatus that forms lines in a predetermined pattern on a workpiece such as a thin-film solar cell wound from a first roll to a second roll.

[0004] In this laser processing apparatus, the workpiece is placed on an imaging processing stage, and the surface to be processed is imaged by an imaging unit. Based on the imaging signal thus obtained, the position coordinate values of a plurality of points on the primary patterning line already formed on the surface to be processed are calculated. Thereafter, the workpiece is transferred to a processing stage, and the surface to be processed is imaged by an imaging unit on the processing stage side. The scanning position of the laser light is corrected according to the difference between the position coordinate values on the primary patterning based on the imaging signal thus obtained and the position coordinate values obtained by the processing on the imaging processing stage side. According to the corrected scanning position, the operation of scanning means such as a galvanometer scan mirror is controlled, and the laser light is irradiated onto the workpiece. Thereby, a secondary patterning line is formed on the surface to be processed.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-081392 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] In the laser processing apparatus described in the above Patent Document 1, it is necessary to once stop the workpiece on the imaging processing stage and the processing stage. For this reason, in order to form a line, it is necessary to repeat the conveyance and stop of the workpiece, and the processing time for forming a line on all of the workpiece wound around the first roll becomes long.

[0007] In addition, in the laser processing apparatus described in the above Patent Document 1, since it is necessary to arrange the imaging processing stage and the processing stage side by side in the conveyance direction of the workpiece, the size of the laser processing apparatus becomes large in the conveyance direction of the workpiece.

[0008] In view of such problems, an object of the present invention is to provide a laser processing apparatus capable of quickly forming a line on a film-shaped workpiece conveyed between two rolls while achieving downsizing of the apparatus. [Means for Solving the Problems]

[0009] A laser processing apparatus according to a main aspect of the present invention includes a conveyance unit that conveys a film-shaped workpiece between a first roll and a second roll, a processing head that irradiates a laser beam onto a processed surface of the workpiece, a head transfer unit that moves the processing head in a width direction of the workpiece, a camera disposed upstream of the processing head in a conveyance direction of the workpiece, and a control unit that controls the conveyance unit, the processing head, and the head transfer unit. The control unit moves the processing head by the head transfer unit so that a distance between an irradiation position of the laser beam on the processed surface and a reference line extending along the conveyance direction on the workpiece is maintained at a predetermined target distance while continuously conveying the workpiece from the first roll to the second roll by the conveyance unit.

[0010] According to the laser processing apparatus according to this aspect, since a line is formed on the surface to be processed while the workpiece is conveyed from the first roll to the second roll, the line can be formed on the workpiece wound around the first roll quickly. Further, since the processing head and the camera are only arranged in the conveyance direction, it is possible to suppress the size of the laser processing apparatus from increasing in the conveyance direction. Therefore, while realizing miniaturization of the apparatus, a line can be quickly formed on the film-shaped workpiece conveyed between the two rolls.

[0011] The laser processing apparatus according to this aspect further includes a second camera that is disposed on the downstream side in the conveyance direction of the workpiece with respect to the processing head and is capable of imaging the reference line. The control unit, while continuously conveying the workpiece from the second roll to the first roll by the conveying unit, the distance between the irradiation position of the laser beam on the surface to be processed and a reference line extending along the conveyance direction on the workpiece is configured to move the processing head by the head transfer unit so as to be maintained at a predetermined target distance.

[0012] According to this configuration, a line can be formed not only on the surface to be processed during the forward conveyance from the first roll to the second roll but also during the return conveyance from the second roll to the first roll. Therefore, a line can be formed on the surface to be processed more quickly and efficiently.

[0013] The laser processing apparatus according to this aspect further includes a second camera that is disposed on the downstream side in the conveyance direction of the workpiece with respect to the processing head and is capable of imaging the reference line. The control unit determines whether the distance between the reference line when the workpiece is conveyed from the first roll to the second roll and the line formed by the laser beam during the conveyance is within a predetermined threshold range set based on the target distance, based on the captured image from the second camera.

[0014] According to this configuration, a second camera can be further used to determine whether the distance between the formed line and the reference line is properly maintained. Further, when it is determined that this distance is not within the threshold range, abnormal processing such as notification to that effect or temporary stop can be performed. Thereby, the quality of line formation can be ensured.

[0015] In the laser processing apparatus according to this aspect, the reference line can be the edge in the width direction of the workpiece or a line already formed by irradiation of the laser beam.

[0016] Thereby, the distance between the edge or the already formed line and the line to be formed this time can be maintained at the target distance.

[0017] The laser processing apparatus according to this aspect can be configured such that a plurality of the processing heads are arranged in the width direction.

[0018] According to this configuration, a plurality of lines parallel to the reference line can be simultaneously formed by the plurality of processing heads. Therefore, lines can be formed on the film-shaped workpiece conveyed between two rolls more quickly and efficiently.

[0019] In this configuration, the camera can be arranged for each of the processing heads.

[0020] According to this configuration, based on the captured images of the respective cameras, the target reference line can be accurately detected for each processing head. Therefore, the distance between the line formed by each processing head and its reference line can be properly maintained.

[0021] In the laser processing apparatus according to this aspect, the workpiece is, for example, a solar cell film.

[0022] In this case, the distance between the lines formed in each layer of the solar cell film can be maintained at the target distance. As a result, the distance between adjacent lines can be shortened, and the dead area between these lines that does not contribute to power generation can be reduced. Therefore, the power generation efficiency of the solar cell can be increased. In addition, since each line can be formed quickly and efficiently as described above, the tact time in the manufacture of the solar cell can be shortened.

Effect of the Invention

[0023] As described above, according to the present invention, it is possible to provide a laser processing apparatus capable of quickly forming lines on a film-shaped workpiece conveyed between two rolls while realizing miniaturization of the apparatus.

[0024] The effects or significance of the present invention will become clearer from the description of the embodiments shown below. However, the embodiments shown below are merely examples when implementing the present invention, and the present invention is not limited to those described in the following embodiments at all.

Brief Description of the Drawings

[0025]

Figure 1

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Mode for Carrying Out the Invention

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, an X-axis, a Y-axis, and a Z-axis orthogonal to each other are added to each figure. The X-axis direction is the moving direction of the processing head, the Y-axis direction is the conveyance direction of the workpiece at the irradiation position of the laser beam, and the Z-axis direction is the direction perpendicular to the work surface at the irradiation position of the laser beam.

[0027] <Embodiment 1> FIG. 1 is a perspective view schematically showing the configuration of the laser processing apparatus 1, and FIG. 2 is a side view schematically showing the configuration of the laser processing apparatus 1.

[0028] The laser processing apparatus 1 includes a first roll 11, a second roll 12, an intermediate roller 13, a processing head 20, a camera 31, a head transfer mechanism 40, and a camera transfer mechanism 51. A film-shaped workpiece 60 such as a solar cell film is wound around the first roll 11. The workpiece 60 has a strip shape with a constant width. The workpiece 60 is fed out from the first roll 11, passes through the intermediate roller 13, and is wound around the second roll 12. In this way, the workpiece 60 is conveyed between the first roll 11 and the second roll 12 in the longitudinal direction of the workpiece 60.

[0029] The processing head 20 is disposed directly above the intermediate roller 13. The processing head 20 irradiates the processed surface 60a of the workpiece 60 with the focused laser light. The processing head 20 includes a light source that emits laser light of a predetermined wavelength and an optical system that condenses the laser light emitted from the light source. The optical system may include a lens. The laser light is condensed by this optical system at the irradiation position P11 with a predetermined depth of focus. As shown in Embodiment 2 to be described later, the light source may be disposed outside the processing head 20.

[0030] The camera 31 is disposed upstream of the processing head 20 in the conveyance direction of the workpiece 60 and images a reference line Ls. The reference line Ls is, for example, a line (groove) already formed on the processed surface 60a along the longitudinal direction of the workpiece 60. When such a line is not formed on the processed surface 60a, the reference line Ls may be one edge in the width direction of the workpiece 60.

[0031] The head transfer mechanism 40 moves the processing head 20 in the width direction (here, the X-axis direction) of the workpiece 60. The head transfer mechanism 40 includes, for example, a ball screw and a guide rail extending in the X-axis direction, a motor that drives the ball screw, and a support plate. The support plate is screwed to the ball screw and is guided in the X-axis direction by the guide rail. The processing head 20 is attached to the support plate such that the emission direction of the laser light is the negative Z-axis direction. The head transfer mechanism 40 is configured to be able to linearly transfer the support plate and the processing head 20 precisely and substantially without fluctuation in the X-axis direction.

[0032] As the machining head 20 moves, the irradiation position P11 moves in the width direction (here, the X-axis direction). The moving direction of the machining head 20 does not necessarily have to be perpendicular to the longitudinal direction of the workpiece 60 (the X-axis direction), and it suffices if it has a component in the width direction of the workpiece 60.

[0033] The camera transfer mechanism 51 moves the camera 31 in the width direction of the workpiece 60 (here, the X-axis direction). The configuration of the camera transfer mechanism 51 may be the same as that of the head transfer mechanism 40. In this case, the camera 31 is mounted on the support plate of the camera transfer mechanism 51 so as to face the machined surface 60a. Similar to the head transfer mechanism 40, the moving direction of the camera 31 does not necessarily have to be perpendicular to the longitudinal direction of the workpiece 60 (the X-axis direction), and it suffices if it has a component in the width direction of the workpiece 60.

[0034] The camera 31 is positioned by the camera transfer mechanism 51 at a predetermined position where the reference line Ls can be imaged. For example, the camera 31 is positioned at a position shifted in the longitudinal direction of the workpiece 60 with respect to the machining head 20. Alternatively, the camera 31 may be arranged directly above the reference line Ls.

[0035] The position P21 of the reference line Ls is detected from the captured image of the camera 31. For example, when a straight line passing through the imaging central axis of the camera 31 and parallel to the X-axis is set on the machined surface 60a, the position of the reference line Ls intersecting this straight line is detected as the position P21 of the reference line Ls. When this position P21 is aligned with the irradiation position P11 in the X-axis direction, the machining head 20 is position-adjusted by the head transfer mechanism 40 so that the distance between these positions becomes the target distance. This control is performed by the control unit 101 (see FIG. 4) as described later.

[0036] While the workpiece 60 is being conveyed from the first roll 11 to the second roll 12, a line (groove) extending in the longitudinal direction of the workpiece 60 is formed on the machined surface 60a by irradiating the machined surface 60a with laser light from the machining head 20.

[0037] FIG. 3 is a diagram showing the configuration of the workpiece 60 when the workpiece 60 is a monocrystalline integrated structure solar cell film.

[0038] FIG. 3 shows the configuration of the workpiece 60 in a state where all the lines are formed. The workpiece 60 is configured by laminating a transparent conductive layer 62, a power generation / absorption layer 63, and a conductive layer 64 on the upper surface of a substrate 61. Grooves (lines 62a, 63a, 64a) are formed in these layers along predetermined patterning lines. These lines 62a, 63a, 64a are formed by the above-described processing head 20.

[0039] In the manufacturing process, first, the transparent conductive layer 62 is formed on the substrate 61 with a predetermined thickness to form the workpiece 60. While transporting the workpiece 60 from the first roll 11 to the second roll 12, laser light is irradiated from the processing head 20 onto the workpiece surface 60a to form the line 62a. When one line 62a is thus formed, the workpiece 60 is wound back from the second roll 12 to the first roll 11. Then, while transporting the workpiece 60 from the first roll 11 to the second roll 12 again, laser light is irradiated from the processing head 20 onto the workpiece surface 60a to form the next line 62a. The above operation is repeated until all the lines 62a are formed in the transparent conductive layer 62.

[0040] Next, the power generation / absorption layer 63 is formed on the transparent conductive layer 62 with a predetermined thickness to form the workpiece 60. In this case, the power generation / absorption layer 63 is also laminated on the line 62a. The same operation as above is performed on this workpiece 60 to form all the lines 63a.

[0041] Furthermore, a conductive layer 64 is formed on the power generation / absorption layer 63 with a predetermined thickness to form the workpiece 60. In this case, the conductive layer 64 is also laminated on the line 63a. The same operation as described above is performed on this workpiece 60 to form all the lines 64a. The depths of the lines 62a to 64a are included within the range of the focal depth of the laser light irradiated from the processing head 20. By adjusting the intensity of the laser light, the lines 62a to 64a with the target depth can be formed.

[0042] Thereafter, the workpiece 60 is cut with a predetermined width in the longitudinal direction, and further, the portions separated in the X-axis direction by the lines 64a are connected in series. Thereby, a solar cell is formed. Here, the region A1 including the lines 62a to 64a becomes a dead area that does not contribute to power generation. Therefore, it is preferable that this region A1 is as narrow as possible. For this reason, it is preferable that the lines 62a to 64a are as close as possible in the X-axis direction. Thereby, the region contributing to power generation can be expanded, and the power generation efficiency of the single solar cell can be increased.

[0043] FIG. 4 is a block diagram showing the configuration of the laser processing apparatus 1.

[0044] The laser processing apparatus 1 includes a control unit 101, a head transfer unit 102, a camera transfer unit 103, a transfer unit 104, a light source drive unit 105, an imaging processing unit 106, and an operation input unit 107.

[0045] The control unit 101 includes an arithmetic processing unit such as a CPU and a memory, and controls each unit according to a program stored in the memory. The program stored in the memory includes an engine for analyzing the captured image of the camera 31.

[0046] The head transfer unit 102 includes the above-described head transfer mechanism 40 and a driver that drives the head transfer mechanism 40 under the control of the control unit 101. The camera transfer unit 103 includes the above-described camera transfer mechanism 51 and a driver that drives the camera transfer mechanism 51 under the control of the control unit 101. The conveyance unit 104 includes the above-described first roll 11, second roll 12, and intermediate roller 13, and a driver that drives each roll under the control of the control unit 101.

[0047] The light source drive unit 105 drives a light source 21 that emits a laser beam for processing under the control of the control unit 101. The imaging processing unit 106 controls the imaging operation of the camera 31 under the control of the control unit 101, and outputs an imaging image (imaging information) obtained by the imaging operation to the control unit 101. The operation input unit 107 is an interface for receiving operation inputs from the user. The operation input unit 107 outputs information corresponding to the operation input to the control unit 101.

[0048] The control unit 101 controls the conveyance unit 104 to convey the workpiece 60 at a predetermined speed, and controls the light source 21 to irradiate the processing surface 60a with a laser beam of a predetermined intensity. At this time, as described above, the control unit 101 detects the position P21 of the reference line Ls from the imaging image of the camera 31, and when this position P21 is aligned with the irradiation position P11, controls the head transfer unit 102 so that the distance between these positions becomes the target distance. By this control, a line extending in the longitudinal direction of the workpiece 60 is formed on the processing surface 60a while the distance from the reference line Ls is maintained at the target distance.

[0049] FIG. 5 is a diagram showing the positional relationship between the processing head 20 and the camera 31.

[0050] In FIG. 5, C-Pd is the distance (mm) in the conveyance direction from the imaging center position of the camera 31 to the irradiation position P11 of the laser beam by the processing head 20. Here, assuming the conveyance speed of the workpiece 60 is F-Ys (mm / second) and the time required for the process of detecting the position P21 on the reference line from the captured image of the camera 31 is C-Lpt (seconds), and the time required for the process of moving the irradiation position to the target position (the position at the target distance from the position P21) is L-Ppt (seconds), the positional relationship between the processing head 20 and the camera 31 can be defined as follows.

[0051] C-Pd = (C-Lpt + L-Ppt) × F-Ys …(1)

[0052] By arranging the processing head 20 and the camera 31 so as to satisfy this relationship, when the position P21 on the reference line aligns with the irradiation position P11, the head transfer unit 102 can be controlled so that the distance between these positions becomes the target distance.

[0053] FIG. 6 is a plan view schematically showing the line formation operation.

[0054] In FIG. 6, the line L1 already formed on the workpiece surface 60a is used as the reference line, and the line L2 is being formed. A10 is the imaging area of the camera 31. As described above, the position where the straight line passing through the intermediate position in the Y-axis direction of the imaging area A10 intersects the reference line (line L1) is detected as the position P21 of the reference line. The position P21' aligned with the irradiation position P11 is detected at the timing that is traced back by the time required for the conveyance of the distance C-Pd from the state of FIG. 6. The position of the irradiation position P11 is controlled in the X-axis direction so that the distance from this position P21' becomes the target distance D2. Thereby, the distance between the line L1 which is the reference line and the line L2 to be formed this time is maintained at the target distance D2.

[0055] Note that the line L1 initially formed on the work surface 60a is formed with reference to the edge 60b of the workpiece 60. As a result, the distance between the edge 60b, which is the reference line, and the initially formed line L1 is maintained at the target distance D1.

[0056] When the conveyance of the workpiece 60 is completed from the state of FIG. 6 and the formation of the line L2 is finished, as described above, the workpiece 60 is rewound onto the first roll 11. Thereafter, the workpiece 60 is conveyed to the second roll 12 again, and the next line is formed. In this way, lines are sequentially formed on the work surface 60a. When all the lines to be formed on the work surface 60a are formed, the operation of forming lines on the work surface 60a is completed.

[0057] FIG. 7 is a flowchart showing the line formation process for the work surface 60a.

[0058] FIG. 7 shows the processes executed from the start of the conveyance of the workpiece 60 from the first roll 11 to the second roll 12 until the conveyance is completed. As described above, when the process of FIG. 7 is completed, after the workpiece 60 is rewound onto the first roll 11, the conveyance of the workpiece 60 from the first roll 11 to the second roll 12 is started again, and the process of FIG. 7 is executed.

[0059] The control unit 101 acquires a captured image from the camera 31 (S11), and executes image processing on the acquired captured image (S12). By this image processing, the control unit 101 detects the position P21 on the reference line. The control unit 101 sets the position separated from the detected position P21 by the target distance as the next moving position of the irradiation position P11, and calculates the amount and direction (X-axis direction) of movement for shifting the current irradiation position P11 to the next moving position (S13). The control unit 101 moves the processing head 20 so that the irradiation position P11 moves to the next moving position (S14).

[0060] The control unit 101 determines whether or not the conveyance operation of the workpiece 60 has been completed (S15). If the conveyance operation has not been completed (S15: NO), the control unit 101 returns the process to step S11 and repeats the same process. As a result, the formation of the line proceeds while the irradiation position P11 is adjusted. The control unit 101 repeats the same process until the conveyance operation of the workpiece 60 is completed (S15: NO). Thereafter, when the conveyance operation is completed (S15: YES), the control unit 101 ends the current process.

[0061] FIG. 8 is a timing chart showing the operations of the respective parts in the line formation process of FIG. 7.

[0062] In the first, second, and third rows from the top of FIG. 8, timing charts of the timing of acquiring a captured image from the camera 31, the processing time C-Lpt for processing the acquired captured image, and the timing of the processing time L-Ppt for moving the processing head 20 are respectively shown.

[0063] The camera 31 performs imaging at each period T1 to acquire a captured image (S11 in FIG. 7). The control unit 101 processes the captured image acquired from the camera 31 to detect the position P21 on the reference line (S12 in FIG. 7), and calculates the next movement position (movement amount and movement direction) of the irradiation position P11 based on the detected position P21 (S13 in FIG. 7, processing time C-Lpt). The control unit 101 moves the irradiation position P11 by the calculated movement amount and movement direction (S14 in FIG. 7, processing time L-Ppt). The control unit 101 repeatedly executes the same process at each period T1.

[0064] In the fourth and fifth rows from the top of FIG. 8, the reference line and the line formed this time (formed line) are schematically shown respectively.

[0065] During the conveying operation, the workpiece 60 vibrates slightly in the width direction at a predetermined cycle. For this reason, the reference line also vibrates in the width direction at a predetermined cycle. In the fourth row from the top in FIG. 8, the reference line vibrating in this way is shown by a solid line. Also, in the fourth row from the top in FIG. 8, the state where the solid reference line has moved in the conveying direction by the distance C-Pd is shown by a dashed line. The relationship of the above formula (1) holds between the processing times C-Lpt, L-Ppt and the conveying speed F-Ys, and the distance C-Pd.

[0066] As shown in the bottom row of FIG. 8, in step S13 of FIG. 7, the control unit 101 calculates the movement amounts ΔD1 to ΔD3 for moving the current irradiation position P11 to the next movement position. These movement amounts ΔD1 to ΔD3 are substantially equal to the difference between the position P21 on the reference line detected in each imaging and the position P21 on the reference line detected in the previous imaging.

[0067] As shown in the bottom row of FIG. 8, after the processing time L-Ppt for the movement of the processing head 20 ends, during the period ΔT until the next processing time L-Ppt starts, since the processing head 20 does not move, the irradiation position P11 also does not move. The irradiation position P11 moves in the X-axis direction by the movement amounts ΔD1 to ΔD3 during the processing time L-Ppt.

[0068] Therefore, the distance between the dashed reference line and the formation line coincides with the above-described target distance at the end timing of the processing time L-Ppt, that is, at the timing when the movement of the irradiation position P11 is completed, but deviates slightly from the target distance at other timings. However, due to the movement control of the irradiation position P11, the formation line vibrates in a similar tendency to the vibration of the reference line, so the distance between the reference line and the formation line substantially follows the target distance.

[0069] Therefore, the target line and the formed line are significantly close to each other, or the intersection of the two lines is suppressed. Thus, the target distance between the reference line and the formed line can be set small. When the workpiece 60 is a solar cell film as shown in FIG. 3, the area A1 (dead area) that does not contribute to power generation can be reduced. Thereby, the power generation efficiency of the single solar cell can be increased.

[0070] In addition, in Embodiment 1, since the positional relationship between the processing head 20 and the camera 31 is set so that the above formula (1) holds, as in the timing chart of FIG. 8, the distance (C-Lpt + L-Ppt)·F-Ys that the workpiece 60 is conveyed during the time obtained by integrating the processing time C-Lpt and the processing time L-Ppt is the same as the distance C-Pd between the processing head 20 and the camera 31 in the conveyance direction.

[0071] However, when the conveyance speed of the workpiece 60 is decelerated to a conveyance speed F-Ys’ slower than the conveyance speed F-Ys of the above formula (1), the distance (C-Lpt + L-Ppt)·F-Ys’ that the workpiece 60 is conveyed during the time elapsed after integrating the processing time C-Lpt and the processing time L-Ppt becomes shorter than the distance C-Pd between the processing head 20 and the camera 31 in the conveyance direction. In this case, as shown in FIG. 8, when the image processing and the movement processing of the processing head 20 are continuously performed in response to the acquisition of the captured image, the irradiation position P11 at the timing when the movement processing of the processing head 20 is completed will not be aligned with the position P21 on the reference line detected from the captured image in the X-axis direction.

[0072] In this case, it is also possible to calculate the distance C-Pd from the above formula (1) using the decelerated conveyance speed F-Ys’ as the conveyance speed F-Ys, and re-set the positional relationship between the processing head 20 and the camera 31 based on the calculated distance C-Pd. However, this method requires re-setting the positional relationship every time the conveyance speed changes, which is complicated.

[0073] On the other hand, by using an offset time for delaying the movement process of the image processing or processing head 20 in accordance with the deceleration of the conveyance speed, it is possible to cope with the deceleration of the conveyance speed without resetting the distance C-Pd. In this case, the offset time OSpt is calculated so that the following relational expression holds by using the decelerated conveyance speed F-Ys'.

[0074] C-Pd = (C-Lpt + L-Ppt + OSpt) × F-Ys’ …(2)

[0075] Then, it is only necessary to delay the start timing of the image processing or the start timing of the movement process of the processing head 20 by this offset time OSpt.

[0076] For example, as shown in FIG. 3, when the workpiece 60 is a solar cell film, due to the materials constituting the transparent conductive layer 62, the power generation / absorption layer 63, and the conductive layer 64, and the depths of the lines 62a, 63a, 64a, etc., the conveyance speeds of the workpiece 60 when forming the lines 62a, 63a, 64a may be different from each other. Also, when the thicknesses and materials of the transparent conductive layer 62, the power generation / absorption layer 63, and the conductive layer 64 are different for each type of solar cell, the conveyance speeds of the workpiece 60 when forming the lines 62a, 63a, 64a may be different from each other for each type of solar cell.

[0077] In such a case, the positional relationship (distance C-Pd in the conveyance direction) between the processing head 20 and the camera 31 may be set from the above formula (1) based on the assumed fastest conveyance speed F-Ys. Then, when a conveyance speed F-Ys’ slower than the fastest conveyance speed F-Ys is set via the operation input unit 107 in FIG. 4, the control unit 101 applies the conveyance speed F-Ys’ to the above formula (2) to calculate the offset time OSpt, and it is only necessary to delay the start timing of the image processing or the start timing of the movement process of the processing head 20 by the calculated offset time OSpt. Thereby, even when the conveyance speed F-Ys is changed, the irradiation position P11 at the timing when the movement process of the processing head 20 is completed and the position P21 on the reference line detected from the captured image can be arranged in the X-axis direction.

[0078] <Effect of Embodiment 1> According to the above Embodiment 1, the following effects are achieved.

[0079] As shown in FIGS. 1, 2, and 4, the laser processing apparatus 1 includes a conveyance unit 104 that conveys the film-shaped workpiece 60 from the first roll 11 to the second roll 12, a processing head 20 that irradiates the laser beam onto the processed surface 60a of the workpiece 60, a head transfer unit 102 (head transfer mechanism 40) that moves the processing head 20 in the width direction of the workpiece 60, a camera 31 disposed upstream of the processing head 20 in the conveyance direction of the workpiece 60, and a control unit 101 that controls the conveyance unit 104, the processing head 20, and the head transfer unit 102. As described with reference to FIG. 6, while continuously conveying the workpiece 60 from the first roll 11 to the second roll 12 by the conveyance unit 104, the control unit 101 moves the processing head 20 by the head transfer unit 102 so that the distance between the irradiation position P11 of the laser beam on the processed surface 60a and the reference line (edge 60b or line L1) extending along the conveyance direction on the workpiece 60 is maintained at the predetermined target distances D1 and D2.

[0080] According to this configuration, since the lines L1 and L2 are formed on the processed surface 60a while the workpiece 60 is conveyed from the first roll 11 to the second roll 12, the lines L1 and L2 can be quickly formed on the workpiece 60 wound around the first roll 11. Further, since only the processing head 20 and the camera 31 are arranged in the conveyance direction, an increase in the size of the laser processing apparatus 1 in the conveyance direction can be suppressed. Therefore, while realizing miniaturization of the apparatus, lines can be quickly formed on the film-shaped workpiece 60 conveyed between the first roll 11 and the second roll 12.

[0081] As described with reference to FIG. 6, the reference line is the edge 60b in the width direction of the workpiece 60 or the line L1 already formed by the irradiation of the laser beam.

[0082] As a result, the distances between the edge 60b or the already formed line L1 and the lines L1 and L2 to be formed this time can be maintained at the target distances D1 and D2.

[0083] As described with reference to FIG. 3, the workpiece 60 is, for example, a solar cell film.

[0084] In this case, the distances between the lines 62a, 63a, and 64a formed in each layer of the solar cell film can be maintained at the target distances. As a result, the distance between adjacent lines can be shortened, and the area A1 (dead area) between these lines that does not contribute to power generation can be reduced. Therefore, the power generation efficiency of the solar cell can be increased. In addition, since each of the lines 62a, 63a, and 64a can be formed quickly and efficiently as described above, the tact time in the manufacture of the solar cell can be shortened.

[0085] <Modification Example 1> In the timing chart of FIG. 8, the next captured image was acquired after the processing time L-Ppt for moving the processing head 20 ended, but the timing for performing each process is not limited to this. In Modification Example 1, the next captured image is acquired during the processing time L-Ppt, and the next processing sequence is performed in parallel.

[0086] FIG. 9 is a timing chart showing the operations of each part in Modification Example 1.

[0087] In step S13 of FIG. 7, the moving position is set. Simultaneously with the movement of the processing head in step S14, steps S11 to S13 for calculating the next moving position are started. The movement amounts ΔD1 to ΔD3 for the next moving position are calculated as the difference between the next moving position and the current moving position. In FIG. 9, the control unit 101 moves the irradiation position P11 to the next moving position during the processing time L-Ppt, and then further moves the irradiation position P11 to the next moving position P11 during the next processing time L-Ppt.

[0088] <Effect of Modification Example 1> According to Modification Example 1, as shown in FIG. 9, the forming line approaches the waveform of the reference line which is a dashed line. Therefore, compared with Embodiment 1 shown in FIG. 8, the distance between the reference line and the forming line can be maintained at the target distance more accurately.

[0089] <Modification Example 2> FIG. 10 is a side view schematically showing the configuration of the laser processing apparatus 1 according to Modification Example 2.

[0090] In Modification Example 2, a camera 32 capable of imaging the reference line is further arranged on the downstream side in the conveyance direction of the forward path with respect to the processing head 20. The camera 32 is moved in the Y-axis direction by a camera transfer mechanism 52. The camera transfer mechanism 52 is included in the camera transfer unit 103 of FIG. 4.

[0091] Thereby, a line can be formed on the work surface 60a not only during the conveyance of the workpiece 60 in the forward path from the first roll 11 to the second roll 12 but also during the conveyance of the workpiece 60 in the return path when the workpiece 60 is wound back from the second roll 12 to the first roll 11. The control unit 101 detects the position P22 on the reference line from the captured image of the camera 32 during the return conveyance operation, and controls the position of the processing head 20 based on the detected position P22 so that the distance between the irradiation position P11 and the reference line becomes a predetermined target distance. This control may be the same as the processing of FIG. 7 or FIG. 9.

[0092] Note that during the forward conveyance operation, the formation state of the line in the current processing operation may be monitored from the captured image of the camera 32. Similarly, during the return conveyance operation, the formation state of the line in the current processing operation may be monitored from the captured image of the camera 31.

[0093] FIG. 11 is a flowchart showing the process of monitoring the formation state of the forming line according to Modification Example 2.

[0094] The control unit 101 acquires a captured image from the camera on the downstream side in the conveyance direction among the cameras 31 and 32 (S31), processes the acquired captured image, and calculates the distance between the reference line and the line currently being formed (S32). The control unit 101 determines whether the calculated distance is equal to or greater than a predetermined threshold Th1 and equal to or less than a predetermined threshold Th2 (S33). This threshold Th1 is set to be smaller than the target distance between the reference line and the line currently being formed. The threshold Th1 is set to a value that can detect whether there is a possibility that the reference line and the line currently being formed intersect. For example, the threshold Th1 can be set to about half of the target distance. Similarly, the threshold Th2 is set to be larger than the target distance between the reference line and the line currently being formed. The threshold Th2 is set to a value that can detect whether there is a possibility that the reference line and the line currently being formed are too far apart.

[0095] If the distance calculated in step S32 is less than the threshold Th1 or greater than Th2 (S33: NO), the control unit 101 executes a predetermined abnormality process (S34). For example, the control unit 101 executes a process of notifying the user that there is a possibility that the reference line and the line currently being formed intersect or are too far apart. Alternatively, the control unit 101 may execute a process of interrupting the line formation operation. In this case, the control unit 101 ends the process of FIG. 11.

[0096] If the determination in step S33 is YES, the control unit 101 skips step S34 and determines whether the current conveyance operation has ended (S35). The control unit 101 repeatedly executes the processes of steps S31 to S34 until the current conveyance operation ends (S35: NO). After that, when the current conveyance operation ends (S35: YES), the control unit 101 ends the process of FIG. 11.

[0097] <Effect of Modification Example 2> As shown in FIG. 10, the laser processing apparatus 1 is disposed on the downstream side in the conveyance direction of the workpiece 60 with respect to the processing head 20, and further includes a second camera 32 capable of imaging a reference line. While continuously conveying the workpiece 60 from the second roll 12 to the first roll 11 by the conveyance unit 104, the control unit 101 moves the processing head 20 by the head transfer unit 102 (head transfer mechanism 40) so that the distance between the irradiation position P11 of the laser beam on the processed surface 60a and the reference line extending along the conveyance direction on the workpiece 60 is maintained at a predetermined target distance.

[0098] According to this configuration, lines can be formed on the processed surface 60a not only in the forward conveyance from the first roll 11 to the second roll 12 but also in the return conveyance from the second roll 12 to the first roll 11. Therefore, lines can be formed on the processed surface 60a more quickly and efficiently.

[0099] As shown in FIG. 11, the control unit 101 determines, based on the captured image from the second camera 32, whether the distance between the reference line when conveying the workpiece 60 from the first roll 11 to the second roll 12 and the line formed by the laser beam during the conveyance is equal to or greater than a predetermined threshold Th1 smaller than the target distance and equal to or less than a predetermined threshold Th2 greater than the target distance (S31 to S33).

[0100] According to this configuration, the second camera can be further used to determine whether the distance between the formed line and the reference line is properly maintained. Also, when it is determined that this distance is less than the threshold Th1 or greater than the threshold Th2 (S33: NO), abnormal processing such as notification to that effect or temporary stop can be performed (S34). Thereby, the quality of line formation can be ensured.

[0101] In this second modification example, a predetermined threshold Th1 smaller than the target distance and a predetermined threshold Th2 greater than the target distance are set, but only one of them may be set.

[0102] <Embodiment 2> In the above-described Embodiment 1, only one processing head 20 was arranged in the laser processing apparatus 1. In contrast, in Embodiment 2, a plurality of processing heads 20 are arranged in the laser processing apparatus 1.

[0103] FIG. 12 is a plan view showing the configuration of the laser processing apparatus 1 according to Embodiment 2.

[0104] As shown in FIG. 12, the laser processing apparatus 1 includes three processing heads 20a to 20c, three cameras 31a to 31c, and three cameras 32a to 32c. The three processing heads 20a to 20c are each moved in the X-axis direction by a head transfer mechanism 40. The three cameras 31a to 31c are each moved in the X-axis direction by a camera transfer mechanism 51. The three cameras 32a to 32c are each moved in the X-axis direction by a camera transfer mechanism 52.

[0105] The head transfer mechanism 40 and the camera transfer mechanisms 51 and 52 are supported by a pair of support members 71 and 72 that stand upright in a columnar shape in the positive Z-axis direction from the installation surface of the laser processing apparatus 1. The head transfer mechanism 40 individually moves the processing heads 20a to 20c. The camera transfer mechanism 51 individually moves the cameras 31a to 31c, and the camera transfer mechanism 52 individually moves the cameras 32a to 32c.

[0106] A unit for forming one line is constituted by the processing head 20a and the cameras 31a and 32a. Similarly, a unit for forming one line is constituted by the processing head 20b and the cameras 31b and 32b, and a unit for forming one line is constituted by the processing head 20c and the cameras 31c and 32c. The positional relationship in the conveyance direction of the processing head and the two cameras in each unit is the same as that in FIG. 10.

[0107] In Embodiment 2, a light source unit 23 that emits laser light is provided separately from the processing heads 20a to 20c. The light source unit 23 includes a light source that emits laser light and a collimator lens that collimates the laser light emitted from the light source. Further, the processing heads 20a, 20b, 20c are provided with optical systems 22a, 22b, 22c that branch the laser light emitted from the light source unit 23 and incident from the side into the number of processing heads (three in this embodiment). The light source unit 23 emits laser light in the negative X-axis direction.

[0108] FIG. 12 shows the formation process of lines L1a, L1b, and L1c in the first conveyance of the workpiece 60 in the forward path. Here, the edge 60b on the positive X-axis side of the workpiece 60 is used as a reference line. The position of the reference line (edge 60b) is acquired from the captured image of the camera 31a. The three processing heads 20a, 20b, 20c are controlled such that the irradiation positions of the laser light are at target distances D1a, D1b, and D1c from the reference line (edge 60b). The movement control for each of the processing heads 20a, 20b, 20c is the same as that in the above Embodiment 1 or Modification Example 1. Thereby, the lines L1a, L1b, and L1c are formed on the workpiece surface 60a. In that process, similar to Modification Example 2, the processing of FIG. 11 may be performed using the captured images of the cameras 32a to 32c.

[0109] FIG. 13 is a plan view showing the formation process of lines L1a, L1b, and L1c in the conveyance of the workpiece 60 in the return path according to Embodiment 2.

[0110] Here, the lines L1a, L1b, and L1c formed by the forward conveyance shown in FIG. 12 are used as reference lines. The positions of the reference lines L1a, L1b, and L1c are respectively obtained from the captured images of the cameras 32a, 32b, and 32c. The three processing heads 20a, 20b, and 20c are controlled such that the irradiation positions of the laser light are at target distances D2a, D2b, and D2c from the reference lines (lines L1a, L1b, and L1c). The movement control for each of the processing heads 20a, 20b, and 20c is the same as that in the above-described Embodiment 1 or Modified Example 1. Thereby, the lines L2a, L2b, and L2c are formed on the work surface 60a. In this process, similar to Modified Example 2, the processing of FIG. 11 may be performed using the captured images of the cameras 31a to 31c.

[0111] When the return conveyance is completed and the formation of the lines L2a, L2b, and L2c is finished, the forward conveyance of the workpiece 60 is started again, and the laser light is irradiated onto the work surface 60a from the three processing heads 20a, 20b, and 20c. In this forward conveyance, the lines L2a, L2b, and L2c formed by the return conveyance are used as reference lines, and the movement control of the processing heads 20a, 20b, and 20c is performed. Thereby, the next lines are formed on the work surface 60a. Thus, until all the processing lines are formed, the forward conveyance and the return conveyance are repeated, and the movement control for the three processing heads 20a, 20b, and 20c is performed.

[0112] <Effects of Embodiment 2> As shown in FIGS. 12 and 13, in the laser processing apparatus 1, a plurality of processing heads 20a to 20c are arranged in the width direction of the workpiece 60.

[0113] According to this configuration, a plurality of lines L1a to L1c, L2a to L2c parallel to the reference line can be simultaneously formed by the plurality of processing heads 20a to 20c. Therefore, lines can be formed more quickly and efficiently on the film-shaped workpiece 60 conveyed between the first roll 11 and the second roll 12.

[0114] As shown in FIGS. 12 and 13, in the laser processing apparatus 1, cameras 31a to 31c and cameras 32a to 32c are arranged for each of the processing heads 20a to 20c.

[0115] According to this configuration, based on the captured images of the respective cameras 31a to 31c, the target reference line can be accurately detected for each of the processing heads 20a to 20c. Therefore, the distance between the line formed by each of the processing heads 20a to 20c and its reference line can be appropriately maintained.

[0116] In the configuration examples of FIGS. 12 and 13, three sets of a processing head and two cameras are arranged, but two or four or more sets may be arranged in the laser processing apparatus 1.

[0117] Further, in the configuration examples of FIGS. 12 and 13, the laser light from one light source unit 23 is branched to a plurality of processing heads, but the light source unit 23 may be provided for each of the processing heads 20.

[0118] <Other Modification Examples> In the above-described First Embodiment, the processing head 20 and the camera 31 are individually moved, but as long as the camera 31 can image the reference line, the processing head 20 and the camera 31 may be integrated and moved integrally. This also applies to the configurations of Modification Example 2 and the Second Embodiment. In the configurations of Modification Example 2 and the Second Embodiment, the downstream camera may be further integrated.

[0119] Further, the camera 31 does not necessarily need to move, and as long as it can detect all the reference lines necessary for the movement control of the processing head 20, one camera including all the reference lines in the imaging field may be fixedly arranged, or a plurality of cameras capable of imaging a predetermined number of each of all the reference lines may be fixedly arranged. This also applies to the camera 32.

[0120] Moreover, the configuration of the laser processing apparatus 1 is not limited to the configurations shown in the above-described Embodiments 1 and 2. For example, in the configuration of FIG. 2, only one intermediate roller 13 is disposed between the first roll 11 and the second roll 12, but two or more intermediate rollers may be disposed between the first roll 11 and the second roll 12.

[0121] In addition, in the above-described Embodiment 1, the solar cell film of FIG. 3 is exemplified as the workpiece 60. However, as long as a line is formed in the conveyance direction, the workpiece 60 may be another film-shaped structure.

[0122] In addition, various modifications can be appropriately made to the embodiments of the present invention within the scope of the technical idea shown in the claims.

Explanation of Reference Numerals

[0123] 1 Laser processing apparatus 11 First roll 12 Second roll 20, 20a to 20c Processing head 31, 31a to 31c Camera 32, 32a to 32c Camera (second camera) 60 Workpiece 60a Workpiece surface 60b Edge 62a to 62c Line 101 Control unit 102 Head transfer unit 104 Conveyance unit D1, D2, D1a to D1c, D2a to D2c Target distance L1, L2, L1a to L1c, L2a to L2c Line Ls Reference line P11 Irradiation position P21 Position of reference line

Claims

1. A conveying unit that conveys a film-like workpiece between a first roll and a second roll; A processing head that irradiates a laser beam onto the processed surface of the workpiece; A head transfer unit that moves the processing head in the width direction of the workpiece; A camera disposed upstream of the processing head in the conveying direction of the workpiece; A control unit that controls the conveying unit, the processing head, and the head transfer unit, wherein the control unit moves the processing head by the head transfer unit so that the distance between the irradiation position of the laser beam on the processed surface and a reference line extending along the conveying direction on the workpiece is maintained at a predetermined target distance while continuously conveying the workpiece from the first roll to the second roll by the conveying unit. A laser processing apparatus characterized by the above.

2. In the laser processing apparatus according to Claim 1, further comprising a second camera disposed downstream of the processing head in the conveying direction of the workpiece and capable of imaging the reference line, wherein the control unit moves the processing head by the head transfer unit so that the distance between the irradiation position of the laser beam on the processed surface and a reference line extending along the conveying direction on the workpiece is maintained at a predetermined target distance while continuously conveying the workpiece from the second roll to the first roll by the conveying unit. A laser processing apparatus characterized by the above.

3. In the laser processing apparatus according to Claim 1, further comprising a second camera disposed downstream of the processing head in the conveying direction of the workpiece and capable of imaging the reference line, wherein the control unit determines whether the distance between the reference line when the workpiece is conveyed from the first roll to the second roll and the line formed by the laser beam during the conveyance is within a predetermined threshold range set based on the target distance, based on an imaging image from the second camera. A laser processing apparatus characterized by the above.

4. In the laser processing apparatus according to Claim 1, the reference line is an edge in the width direction of the workpiece or a line already formed by irradiation of the laser beam. A laser processing apparatus characterized by the above.

5. In the laser processing apparatus according to any one of Claims 1 to 4, a plurality of the processing heads are arranged in the width direction. A laser processing apparatus characterized by the above.

6. In the laser processing apparatus according to Claim 5, the camera is arranged for each of the processing heads, A laser processing apparatus characterized by the above.

7. In the laser processing apparatus according to Claim 1, the workpiece is a solar cell film, A laser processing apparatus characterized by the above.

Images