Laser processing device

Abstract

To provide a technique that can prevent a stripe pattern from being formed on a result of irradiation, even in a situation where energy variation whose variation cycle is fast occurs in a laser oscillator.SOLUTION: A laser processing device 1 comprises: a laser oscillator 21 that oscillates processing laser light R on the basis of an inputted PWM signal S; a galvano-scanner 18 that emits the oscillated processing laser light R along a scanning line extending in a predetermined direction to an object 7 to be processed; a laser driver 37 that outputs the PWM signal S; and a CPU 41 that can set an operation mode and controls operation of the galvano-scanner 18 and of the laser driver 37 on the basis of the set operation mode. When a first mode is set as the operation mode, the CPU 41 controls the laser driver 37 so that output timings of the PWM signal S are made different between adjacent scanning lines.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present application relates to a technique for laser processing an object. [Background technology]

[0002] Patent Document 1 describes an energy fluctuation correction method and device that detects the energy of laser light being irradiated onto an object and performs feedback correction in real time to prevent stripes from appearing in the irradiation result due to fluctuations in the energy of the laser light during irradiation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-033007 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the energy fluctuation correction method and device described in Patent Document 1, although it is possible to reduce the fluctuation width of swells with a fluctuation cycle of about 1 to 3 seconds by controlling the variable attenuator, the control cannot keep up with energy fluctuations with a fast fluctuation cycle, and the fluctuations cannot be suppressed. As a result, it has been unable to deal with the occurrence of stripes caused by energy fluctuations with a fast fluctuation cycle.

[0005] An object of the present invention is to provide a technique that does not produce stripes in the irradiation result even in a situation where energy fluctuations with a fast fluctuation cycle occur in a laser oscillator. [Means for solving the problem]

[0006] In order to achieve the above object, the laser processing apparatus of the present application is a laser processing apparatus that processes a workpiece by irradiating the workpiece with laser light based on processing data, and is equipped with a laser oscillator unit that oscillates laser light based on an input control signal, a scanning unit that irradiates the oscillated laser light onto the workpiece along a scanning line that advances in a predetermined direction, an output unit that outputs a control signal, a setting unit that can set an operating mode, and a control unit that controls the operation of the scanning unit and the output unit based on the operating mode set by the setting unit, and is characterized in that when the operating mode is set to a first mode, the control unit controls the output unit so that the output timing of the control signal differs between adjacent scanning lines. [Effects of the Invention]

[0007] According to the present application, when the first mode is set as the operating mode, the output unit is controlled so that the output timing of the control signal is made different between adjacent scan lines, so that it is possible to prevent stripes from appearing in the irradiation result even in a situation where the laser oscillator experiences energy fluctuations with a fast fluctuation cycle. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a schematic configuration of a laser processing unit of a laser processing apparatus according to an embodiment of the present application; [Figure 2] 1 is a block diagram showing a control configuration of a laser processing apparatus according to an embodiment of the present application. [Figure 3] 3 shows an example of the transitions of the control signal, laser output, and current of the laser oscillator in FIG. [Figure 4] 10A and 10B are diagrams showing an example of the difference in the fill-in state of the filled-in portion when ((a)) the setting for switching to the first mode is not performed and when ((b)) the setting is performed. [Figure 5] 10A and 10B are diagrams showing the correlation between printing speed and shading pitch, with the F-number of the fθ lens as a parameter, when the driving frequency of the PWM signal is 100 kHz ((a)) and 25 kHz ((b)). [Figure 6]FIG. 6 is a diagram showing table data on which the correlation in FIG. 5(b) is based. [Figure 7] 3 is a flowchart showing the procedure of control processing executed by a laser controller, particularly a CPU, of the laser processing unit of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present application will be described in detail with reference to the drawings.

[0010] Fig. 1 shows a schematic configuration of a laser processing unit 3 of a laser processing apparatus 1 according to an embodiment of the present application, and Fig. 2 shows a control configuration of the laser processing apparatus 1. As shown in Fig. 2, the laser processing apparatus 1 is made up of a print information creation unit 2 and a laser processing unit 3. The print information creation unit 2 is made up of a personal computer or the like.

[0011] As shown in Fig. 1, the laser processing unit 3 performs marking (printing) processing by two-dimensionally scanning a processing laser beam R on a processing surface 8 of a processing object 7. As shown in Fig. 2, the laser processing unit 3 includes a laser controller 6.

[0012] The laser controller 6 is configured by a computer and is connected to the print information creation unit 2 so as to be able to communicate bidirectionally. The laser controller 6 controls the driving of the laser processing unit 3 based on the print information, control parameters, various instruction information, etc. transmitted from the print information creation unit 2.

[0013] The schematic configuration of the laser processing unit 3 will be described with reference to Fig. 1. The laser processing unit 3 includes a laser oscillation unit 12, a light guide unit 15, a dichroic mirror 101, an optical system 70, a camera 103, a galvanometer scanner 18, and an fθ lens 19, and is covered with a housing cover having a substantially rectangular parallelepiped shape (not shown).

[0014] The laser oscillation unit 12 is composed of a laser oscillator 21 and the like. The laser oscillator 21 is composed of a CO2 laser, a YAG laser, or the like, and emits processing laser light R. The beam diameter of the processing laser light R is adjusted (for example, enlarged) by a beam expander (not shown).

[0015] The guide light unit 15 is composed of a visible semiconductor laser 28 (see FIG. 2) and the like. The visible semiconductor laser 28 emits visible laser light Q, which is visible coherent light, for example, red laser light. The visible laser light Q is collimated by a group of lenses (not shown) and then scanned two-dimensionally to project, for example, an image of a printing pattern to be marked (printed) with the processing laser light R, a rectangular image surrounding that image, and the like, as a locus (time afterimage) on the processing surface 8 of the workpiece 7. In other words, the visible laser light Q does not have the ability to perform marking (printing) processing.

[0016] The wavelength of the visible laser light Q is different from the wavelength of the processing laser light R. In this embodiment, for example, the wavelength of the processing laser light R is 1064 nm, and the wavelength of the visible laser light Q is 650 nm.

[0017] The dichroic mirror 101 transmits almost all of the incident processing laser light R. Furthermore, the visible laser light Q is incident at an incident angle of 45 degrees at approximately the center position of the dichroic mirror 101 where the processing laser light R passes, and is reflected onto the optical path of the processing laser light R at a reflection angle of 45 degrees. The reflectance of the dichroic mirror 101 is wavelength dependent. Specifically, the dichroic mirror 101 is surface-treated with a multilayer film structure of dielectric layers, and is configured to have high reflectance for the wavelength of the visible laser light Q and to transmit almost all (99%) of light of other wavelengths.

[0018] 1 indicates an optical axis 10 of the processing laser light R and the visible laser light Q. The direction of the optical axis 10 indicates the path direction of the processing laser light R and the visible laser light Q.

[0019] The optical system 70 includes a first lens 72, a second lens 74, and a moving mechanism 76. In the optical system 70, the processing laser light R and the visible laser light Q, which have passed through the dichroic mirror 101, are incident on and pass through the first lens 72. At this time, the first lens 72 reduces the beam diameters of the processing laser light R and the visible laser light Q. The processing laser light R and the visible laser light Q, which have passed through the first lens 72, are incident on and pass through the second lens 74. At this time, the second lens 74 converts the processing laser light R and the visible laser light Q into parallel beams. The moving mechanism 76 includes an optical system motor 80 (see FIG. 2 ) and a rack-and-pinion (not shown) that converts the rotational motion of the optical system motor 80 into linear motion, and moves the second lens 74 in the direction of the paths of the processing laser light R and the visible laser light Q by controlling the rotation of the optical system motor 80.

[0020] In addition, the moving mechanism 76 may be configured to move the first lens 72 instead of the second lens 74, or may be configured to move both the first lens 72 and the second lens 74 so that the distance between the first lens 72 and the second lens 74 changes.

[0021] The galvanometer scanner 18 performs two-dimensional scanning with the processing laser light R and the visible laser light Q that have passed through the optical system 70. In the galvanometer scanner 18, a galvanometer X-axis motor 31 (see FIG. 2) and a galvanometer Y-axis motor 32 (see FIG. 2) are attached so that their motor shafts are perpendicular to each other, and scanning mirrors 18X and 18Y attached to the tips of the motor shafts face each other on the inside. The scanning mirrors 18X and 18Y are rotated by controlling the rotation of the motors 31 and 32, thereby performing two-dimensional scanning with the processing laser light R and the visible laser light Q. The two-dimensional scanning directions are the X and Y directions.

[0022] The fθ lens 19 focuses the processing laser light R and the visible laser light Q, which have been two-dimensionally scanned by the galvanometer scanner 18, onto the processing surface 8 of the workpiece 7. Therefore, the processing laser light R and the visible laser light Q are two-dimensionally scanned in the X and Y directions on the processing surface 8 of the workpiece 7 by controlling the rotation of each of the motors 31 and 32.

[0023] The processing laser light R and the visible laser light Q have different wavelengths. Therefore, when the distance between the first lens 72 and the second lens 74 in the optical system 70 is constant, the position where the processing laser light R and the visible laser light Q are focused (hereinafter referred to as the "focal position F") will differ in the vertical direction. Therefore, the focal position F of the processing laser light R and the visible laser light Q can be aligned on the processing surface 8 of the workpiece 7 by adjusting the distance between the first lens 72 and the second lens 74 in the optical system 70.

[0024] The camera 103 is provided near the fθ lens 19 while being directed toward the processing surface 8 of the workpiece 7. Thus, the camera 103 may, for example, capture an image of the guide light Q irradiated onto the processing surface 8 of the workpiece 7 and display the image on a liquid crystal display (LCD) 56 (see FIG. 2 ), which will be described later, so that the user can check whether the alignment between the processing image to be performed and the workpiece 7 is appropriate.

[0025] Next, the circuit configurations of the print information creation unit 2 and the laser processing unit 3 that constitute the laser processing device 1 will be described with reference to Fig. 2. First, the circuit configuration of the laser processing unit 3 will be described.

[0026] As shown in FIG. 2, the laser processing unit 3 is composed of a laser controller 6, a galvanometer controller 35, a galvanometer driver 36, a laser driver 37, a semiconductor laser driver 38, an optical system driver 78, a camera 103, and the like. The laser controller 6 controls the entire laser processing unit 3. The galvanometer controller 35, the laser driver 37, the semiconductor laser driver 38, the optical system driver 78, and the like are electrically connected to the laser controller 6. The laser controller 6 and the camera 103 are also connected to an external print information creation unit 2 for bidirectional communication. The laser controller 6 is configured to be able to receive various information transmitted from the print information creation unit 2 (e.g., print information, control parameters for the laser processing unit 3, various instruction information from the user, etc.). The camera 103 is configured to be able to receive various information transmitted from the print information creation unit 2 (e.g., image capture instruction information, etc.) and is also configured to be able to transmit captured images to the print information creation unit 2.

[0027] The laser controller 6 includes a CPU 41, a RAM 42, a ROM 43, etc. The CPU 41 is an arithmetic unit and a control unit that performs overall control of the laser processing unit 3. The CPU 41, the RAM 42, and the ROM 43 are interconnected by a bus (not shown) and exchange data among them.

[0028] The RAM 42 is used to temporarily store various calculation results calculated by the CPU 41, data (XY coordinates) of the print pattern, and the like.

[0029] The ROM 43 stores various programs, such as a program for calculating XY coordinate data of a print pattern based on print information transmitted from the print information creation unit 2 and storing the data in the RAM 42, and a program for calculating XY coordinate data of a square locus of the visible laser light Q and storing the data in the RAM 42. In addition to the above-mentioned programs, the various programs also include a program for storing various control parameters in the RAM 42 indicating various delay values, the thickness, depth, and number of the print pattern corresponding to the print information input from the print information creation unit 2, the laser output of the laser oscillator 21, the laser pulse width of the processing laser light R, the scanning speed of the processing laser light R by the galvanometer scanner 18, and the scanning speed of the visible laser light Q by the galvanometer scanner 18. Furthermore, the ROM 43 stores data such as the start point, end point, focus, and curvature of the font of each character composed of straight lines and elliptical arcs for each font type.

[0030] The CPU 41 performs various calculations and controls based on various programs stored in the ROM 43 .

[0031] The CPU 41 outputs to the galvanometer controller 35 XY coordinate data of the print pattern calculated based on the print information input from the print information creation unit 2, XY coordinate data of the square locus of the visible laser light Q, galvanometer scanning speed information indicating the scanning speed of the visible laser light Q by the galvanometer scanner 18, and the scanning speed of the processing laser light R by the galvanometer scanner 18. The CPU 41 also outputs to the laser driver 37 laser drive information indicating the laser output of the laser oscillator 21 set based on the print information input from the print information creation unit 2, the laser pulse width of the processing laser light R, etc.

[0032] The CPU 41 outputs to the semiconductor laser driver 38 an ON signal instructing the visible semiconductor laser 28 to start lighting up or an OFF signal instructing it to turn off.

[0033] The galvano controller 35 calculates the drive angle, rotation speed, etc. of the galvano X-axis motor 31 and the galvano Y-axis motor 32 based on each piece of information input from the laser controller 6 (for example, XY coordinate data of the print pattern, XY coordinate data of the square trajectory of the visible laser light Q, galvano scanning speed information, etc.), and outputs motor drive information indicating the drive angle and rotation speed to the galvano driver 36. The galvano driver 36 drives and controls the galvano X-axis motor 31 and the galvano Y-axis motor 32 based on the motor drive information input from the galvano controller 35, to perform two-dimensional scanning with the processing laser light R and the visible laser light Q.

[0034] The laser driver 37 drives the laser oscillator 21 based on laser drive information and the like that indicates the laser output of the laser oscillator 21 and the laser pulse width of the processing laser light R, which are input from the laser controller 6. The semiconductor laser driver 38 drives the visible semiconductor laser 28 to turn on or off based on an on signal or off signal input from the laser controller 6.

[0035] The optical system driver 78 controls the driving of the optical system motor 80 based on information input from the laser controller 6, and moves the second lens 74.

[0036] Next, we will explain the circuit configuration of the print information creation unit 2. The print information creation unit 2 includes a control unit 51, an input operation unit 55, a liquid crystal display (LCD) 56, and a CD-ROM drive 58. The input operation unit 55, the LCD display 56, and the CD-ROM drive 58 are connected to the control unit 51 via an input / output interface (not shown).

[0037] The input operation unit 55 is made up of a mouse, keyboard, etc. (not shown), and is used when the user inputs various instruction information, for example.

[0038] The CD-ROM drive 58 reads various data, various application software, etc. from the CD-ROM 57 .

[0039] The control unit 51 controls the entire print information creation unit 2 and includes a CPU 61, RAM 62, ROM 63, and a hard disk drive (HDD) 66. The CPU 61 is an arithmetic unit and control device that controls the entire print information creation unit 2. The CPU 61, RAM 62, and ROM 63 are interconnected by a bus (not shown) and exchange data between them. Furthermore, the CPU 61 and HDD 66 are connected via an input / output interface (not shown) and exchange data between them.

[0040] The RAM 62 is used to temporarily store various calculation results calculated by the CPU 61. The ROM 63 is used to store various programs and the like.

[0041] The HDD 66 stores various application software programs, various data files, and the like.

[0042] Next, a description will be given of problems that may arise when a certain area on the processing surface 8 of the workpiece 7 is filled with the processing laser light R, and how to deal with these problems. Hereinafter, the area to be filled is referred to as a filled-in portion.

[0043] 3 shows an example of the transitions of the control signal S supplied to the laser oscillator 21, the laser output P output from the laser oscillator 21, and the current I supplied to the laser oscillator 21 from a power supply (not shown). In FIG. 3, the horizontal axis represents time, and the vertical axis represents amplitude. The units on the vertical axis are volts (V) for the control signal S and laser output P, ​​and amperes (A) for the current I. In this embodiment, a PWM signal is used as the control signal S, so the control signal S may also be referred to as a PWM signal S.

[0044] The target value of the laser output P is set by the CPU 41 based on the print information input from the print information creation unit 2 as described above, and is output to the laser driver 37. The laser driver 37 outputs a PWM signal S having a duty ratio that sets the laser output P to the target value to the laser oscillator 21. The laser oscillator 21 outputs a processing laser light R such that the laser output P increases as the duty ratio of the PWM signal S increases.

[0045] In the example of Fig. 3, the duty ratio of the PWM signal S is set to 50%. When the laser driver 37 supplies the PWM signal S with a duty ratio of 50% to the laser oscillator 21, the current I supplied from the power supply to the laser oscillator 21 fluctuates as shown in Fig. 3. That is, after the PWM signal S rises to high, the current I supplied to the laser oscillator 21 increases while the signal remains high, and when the PWM signal S falls to low, the current I begins to fall. As a result, the laser output P also fluctuates in the same way as the current I, with a slight delay from the fluctuation of the current I (delay Δt shown in Fig. 3).

[0046] When the laser output P fluctuates in this way, if the laser processing unit 3 fills in the fill area on the processing surface 8 of the workpiece 7 using a unidirectional raster, faint streaks 8A1 of the fill appear in the fill area 8A, becoming noticeable as stripes, as shown in Fig. 4(a). In the example of Fig. 4(a), the processing laser light R is scanned linearly from the start of writing to the end of writing in the Y direction in the fill area 8A, then returned to the start of writing in the Y direction and scanned one pixel in the X direction, and the operation of scanning linearly from the start of writing to the end of writing in the Y direction and printing is repeated until the end of writing in the X direction in the fill area 8A, thereby filling in the fill area using a unidirectional raster. When the fill area 8A is filled in using a one-way raster in this way, adjacent lines, i.e., odd-numbered lines and the next even-numbered lines, or even-numbered lines and the next odd-numbered lines, alternate between dark and light at the same time in synchronization with the PWM signal S, forming dotted lines, resulting in the appearance of multiple light streaks 8A1 in the X direction.

[0047] To make this striped pattern less noticeable, the laser processing apparatus 1 of the present application switches the operating mode (printing mode) when filling in the filled-in area 8A to the first mode, and shifts the phase of the PWM signal S between adjacent lines in the X direction by half a period. Figure 4(b) shows the filled-in area 8A' when the phase of the PWM signal S is shifted by half a period between odd-numbered and even-numbered lines when writing adjacent lines in the X direction. In the filled-in area 8A', light colors appear at positions in the X direction that correspond to dark colors between adjacent lines, so the striped pattern is less noticeable throughout the filled-in area 8A'.

[0048] FIG. 5 shows the correlation between print speed and shading pitch, with the drive frequency of the PWM signal S and each F-number (focal length) of the fθ lens 19 as parameters. Here, shading pitch is the distance from the beginning of one dark area to the beginning of the next dark area. FIG. 5(a) shows the correlation between print speed and shading pitch for each F-number when the drive frequency of the PWM signal S is 100 kHz, and FIG. 5(b) shows the correlation between print speed and shading pitch for each F-number when the drive frequency of the PWM signal S is 25 kHz. Here, the print speed (bits / ms) is calculated by converting the galvano angular velocity of the galvano scanner 18—specifically, the combined angular velocities (rad / s) of the galvano X-axis motor 31 and the galvano Y-axis motor 32—to 65,536 bits assigned to the maximum amplitude (e.g., 25°) of the galvano scanner 18. That is, the printing speed and the galvano angular velocity of the galvano scanner 18 correspond one-to-one.

[0049] As can be seen from comparing Figures 5(a) and 5(b), even when the F-number and printing speed are the same, the higher the driving frequency of the PWM signal S, the narrower the shading pitch. This is because, as the driving frequency of the PWM signal S increases, the period during which the current I increases in Figure 3 becomes shorter, but the period during which it decreases also becomes shorter. Since the decrease reverses to an increase midway through, the fluctuation range of the laser output P becomes smaller. If the upper limit Th of the shading pitch at which the stripes in the filled-in areas are noticeable is set to, for example, 0.5 mm, when a printing speed is set that results in a shading pitch that exceeds the upper limit Th, the laser processing apparatus 1 switches its operating mode to the first mode. In this embodiment, the F-number of the fθ lens 19 is fixed and cannot be changed after manufacturing the laser processing apparatus 1. Therefore, whether the shading pitch exceeds the upper limit Th can be determined solely by the set value of the printing speed. In addition, if the laser processing device 1 is configured so that the F-number of the fθ lens 19 can be changed after manufacture, whether the shading pitch exceeds the upper limit value Th can be determined based on the printing speed and the F-number.

[0050] Fig. 6 shows table data that is the basis of the correlation in Fig. 5(b). This table data may be stored in advance in, for example, the RAM 42 or ROM 43 of the laser controller 6, and may be referred to when determining whether to switch to the first mode.

[0051] The control process executed by the laser processing device 1 configured as above will be explained below with reference to Fig. 7. Fig. 7 shows the procedure of the control process executed by the laser controller 6, particularly the CPU 41. This control process is started, for example, when the laser controller 6 receives print information transmitted from the print information creation unit 2. Hereinafter, in the explanation of the procedure of each process, steps will be represented as "S".

[0052] 7, the CPU 41 analyzes the received print information (S10) and determines whether the analyzed print information contains a filled-in portion (S12). A filled-in portion includes, for example, a graphic that indicates the shape of the filled-in portion and a property that indicates that the graphic is to be filled in, so the CPU 41 can easily determine whether the analyzed print information contains a filled-in portion. Note that the criteria for determining whether a portion is filled in are not limited to this, and if there is a criterion that can distinguish between a filled-in portion and a graphic or character that is not a filled-in portion, the determination can be made based on that criterion.

[0053] If it is determined in S12 that there are no filled-in areas in the analyzed printing information (S12: NO), the CPU 41 performs printing based on the analyzed printing information (S40) without performing phase control of the PWM signal S, that is, without switching the operating mode in S30 described below, and then terminates the control process.

[0054] On the other hand, if the analyzed print information has a filled-in portion (S12: YES), the CPU 41 determines whether the drive frequency of the PWM signal S is 25 kHz or less (S14). This determination is made because, as described above with reference to FIG. 5, if the drive frequency of the PWM signal S is low, such as 25 kHz or less, the shading pitch often exceeds the upper limit Th, at which the striped pattern of the filled-in portion becomes noticeable. Conversely, if the drive frequency of the PWM signal S is high, such as above 25 kHz, there are fewer shading pitches that exceed the upper limit Th, and therefore the number of light streaks of the filled-in portion that appear in the filled-in portion becomes fewer and less noticeable, and there is no need to switch the operating mode in S30, which will be described later.

[0055] If the determination in S14 is that the drive frequency of the PWM signal S is greater than 25 kHz (S14: NO), the CPU 41 proceeds to S40, performs printing based on the analyzed print information without performing phase control of the PWM signal S (S40), and then terminates the control process. On the other hand, if the determination in S14 is that the drive frequency of the PWM signal S is less than or equal to 25 kHz (S14: YES), the CPU 41 determines whether the duty ratio of the PWM signal S is within a range of 45 to 55% (S16). This determination is made because, when the duty ratio of the PWM signal S is within a range of 45 to 55%, the periods during which the current I supplied to the laser oscillator 21 increases and decreases are substantially identical (in FIG. 3 above, the duty ratio of the PWM signal S is 50%, so they are identical), thereby maximizing the fluctuation range of the laser output P. This increases the pitch of the shading, and the striped pattern in the filled-in area is often perceived as more noticeable.

[0056] If the determination in S16 is that the duty ratio of the PWM signal S is not within the range of 45 to 55% (S16: NO), the CPU 41 proceeds to the above-mentioned S40, performs printing based on the analyzed print information without performing phase control of the PWM signal S (S40), and then ends the control process. On the other hand, if the determination in S16 is that the duty ratio of the PWM signal S is within the range of 45 to 55% (S16: YES), the CPU 41 determines whether the print speed exceeds a predetermined threshold (S18). As described above with reference to FIG. 5, as the print speed increases, the shading pitch also increases, so the determination in S18 determines whether the shading pitch will often exceed the upper limit value Th.

[0057] If the determination in S18 is that the printing speed is equal to or less than the predetermined threshold (S18: NO), the CPU 41 proceeds to the above-mentioned S40, performs printing based on the analyzed printing information without performing phase control of the PWM signal S (S40), and then ends the control process. On the other hand, if the determination in S18 is that the printing speed is greater than the predetermined threshold (S18: YES), the CPU 41 acquires the focal length, i.e., the F-number (S20). As described above, in this embodiment, the F-number of the fθ lens 19 is fixed, and the F-number is stored in, for example, the ROM 43, so the CPU 41 acquires the F-number by reading it from the ROM 43.

[0058] Next, the CPU 41 calculates the linear velocity (S22). The linear velocity is the linear velocity when the processing laser light R scans the processing surface 8 of the workpiece 7, and is calculated by multiplying the galvano angular velocity of the galvano scanner 18 by the F-number of the fθ lens 19. The CPU 41 then determines whether the calculated linear velocity exceeds a predetermined threshold value (S24). Since the magnitude of the linear velocity is proportional to the magnitude of the shading pitch, the determination in S24 is whether or not the striped pattern appearing in the filled-in portion is noticeable.

[0059] If the determination in S24 is that the linear velocity is equal to or less than the predetermined threshold (S24: NO), that is, if it is determined that the stripes appearing in the filled-in portion are not noticeable, the CPU 41 performs printing based on the analyzed print information (S40) without performing phase control of the PWM signal S, and then ends the control process. On the other hand, if the determination in S24 is that the linear velocity is greater than the predetermined threshold (S24: YES), that is, if it is determined that the stripes appearing in the filled-in portion are noticeable, the CPU 41 displays suggestions regarding filling-in (S26).

[0060] In this embodiment, the laser processing unit 3 does not have a display for displaying the suggestion, and therefore transmits display data for displaying the suggestion to the control unit 51 of the print information creation unit 2. The CPU 61 of the control unit 51 receives the display data transmitted from the laser processing unit 3 and displays the received display data on the liquid crystal display 56. An example of a suggestion regarding filling in can be a suggestion by displaying the following text: "When filling in the filled-in area, stripes may be noticeable. Would you like to execute control to make the stripes less noticeable?"

[0061] When the user accepts the proposal, for example, through the input operation unit 55 of the print information creation unit 2, the print information creation unit 2 transmits a notification of the input operation to the laser processing unit 3. In response, the CPU 41 of the laser controller 6 determines that the proposal has been accepted (S28: YES), sets the operating mode to the first mode (S30), and then proceeds to S40. When the operating mode is set to the first mode, the laser driver 37 generates a PWM signal S in which the phase of the PWM signal S used when the processing laser beam R prints the odd-numbered lines in the filled-in portion is shifted by a half cycle from the phase of the PWM signal S used when the processing laser beam R prints the next even-numbered line, as described above with reference to FIG. 4(b), and outputs the PWM signal S to the laser oscillator 21. As a result, when printing is performed in S40, a light color appears at the position in the X direction corresponding to the dark color between adjacent lines, and the striped pattern becomes less noticeable throughout the filled-in portion 8A′ as a whole, as shown in FIG. 4(b).

[0062] On the other hand, if the CPU 41 determines that the proposal has not been accepted (S28: NO), it performs printing based on the analyzed printing information without performing phase control of the PWM signal S (S40), and then ends the control process.

[0063] 7, in order to execute the process of S26, it is necessary that all of the determinations of S12 to S18 be "YES," and then the determination of S24 be "YES." However, this is not limiting, and the process of S26 may be executed when the determination of any of S12 to S18 and S28 is "YES." This is because, when the determination of any of S12 to S18 and S28 is "YES," stripes may become noticeable in the filled-in portion.

[0064] In this embodiment, the fill area is filled using a unidirectional raster, but this is not limiting and bidirectional raster filling is also possible. Furthermore, when filling the fill area, the phase of the PWM signal S between adjacent lines is shifted by a half cycle. However, the shifted cycle is not limited to a half cycle and may be any cycle as long as it is not the same cycle. In this case, the laser driver 37 may be provided with two PWM signal generating circuits that generate two PWM signals S with different phases. One PWM signal generating circuit generates the PWM signal S when the processing laser beam R prints the odd-numbered lines in the fill area, and the other PWM signal generating circuit generates the PWM signal S when the processing laser beam R prints the subsequent even-numbered lines. The two PWM signal generating circuits may be configured by delaying a clock signal supplied to one PWM signal generating circuit using a delay circuit and supplying the delayed signal to the other PWM signal generating circuit. The delay time of the delay circuit may also be user-adjustable. Furthermore, the number of PWM signal generating circuits is not limited to two, but three or more PWM signal generating circuits with different phases may be used.

[0065] As described above, the laser processing apparatus 1 of this embodiment is a laser processing apparatus that processes the workpiece 7 by irradiating the workpiece 7 with processing laser light R based on printing information, and is equipped with a laser oscillator 21 that oscillates the processing laser light R based on an input PWM signal S, a galvanometer scanner 18 that irradiates the workpiece 7 with the oscillated processing laser light R along a scan line that advances in a predetermined direction, a laser driver 37 that outputs the PWM signal S, and a CPU 41 that can set an operating mode and controls the operation of the galvanometer scanner 18 and the laser driver 37 based on the set operating mode, and is characterized in that when the operating mode is set to the first mode, the CPU 41 controls the laser driver 37 so that the output timing of the PWM signal S differs between adjacent scan lines.

[0066] In this way, in the laser processing apparatus 1 of this embodiment, when the operating mode is set to the first mode, the laser driver 37 is controlled so that the output timing of the PWM signal S differs between adjacent scan lines. This makes it possible to prevent stripes from appearing in the irradiation result even in a situation where the laser oscillator 21 experiences energy fluctuations with a fast fluctuation cycle.

[0067] Incidentally, in this embodiment, the print information is an example of "processing data." The processing laser light R is an example of "laser light." The object 7 to be processed is an example of "work." The PWM signal S is an example of "control signal." The laser oscillator 21 is an example of "laser oscillation unit." The galvano scanner 18 is an example of "scanning unit." The laser driver 37 is an example of "output unit." The CPU 41 is an example of "setting unit" and "control unit."

[0068] Furthermore, when the first mode is set, the CPU 41 controls the laser driver 37 so that the output timing of the PWM signal S differs by half a cycle between adjacent scan lines. This makes it possible to prevent stripes from appearing in the irradiation result even when the laser oscillator 21 experiences energy fluctuations with a fast fluctuation cycle.

[0069] The laser processing apparatus 1 of this embodiment is further characterized by including a CPU 41 that analyzes the printed information and determines whether the printed information includes data for filling the workpiece 7, and an LCD display 56 that issues a notification urging the user to set the laser processing mode to the first mode when the CPU 41 determines that the printed information includes data for filling the workpiece 7. If the printed information includes data for filling the workpiece 7, stripes may be noticeable in the filled areas. Therefore, it is possible to urge the user to set the laser processing mode to the first mode to prevent the stripes from being noticeable. The CPU 41 is an example of an "analysis unit." The LCD display 56 is an example of an "alert unit."

[0070] The laser processing device 1 of this embodiment is further characterized by including a CPU 41 that acquires the duty ratio of the PWM signal S, and a liquid crystal display 56 that issues a notification urging the user to set to the first mode when the acquired duty ratio is in the range of 45 to 55%. When the acquired duty ratio is in the range of 45 to 55%, stripes may be noticeable in the filled-in area, so it is possible to urge the user to set to the first mode to make the stripes less noticeable.

[0071] The laser processing device 1 of this embodiment is characterized by further including a CPU 41 that acquires the drive frequency of the PWM signal S, and a liquid crystal display 56 that issues a notification urging the user to set to the first mode when the acquired drive frequency is 25 kHz or less. When the acquired drive frequency is 25 kHz or less, stripes may be noticeable in the filled-in areas, so it is possible to urge the user to set to the first mode to make the stripes less noticeable.

[0072] The laser processing apparatus 1 of this embodiment is characterized by further including a CPU 41 that acquires the linear velocity of the processing laser light R irradiated by the galvanometer scanner 18 on the workpiece 7, and a liquid crystal display 56 that issues a notification urging the user to set to the first mode when the acquired linear velocity is greater than a predetermined threshold. When the acquired linear velocity is greater than the predetermined threshold, stripes may be noticeable in the filled-in area, so it is possible to urge the user to set to the first mode to make the stripes less noticeable.

[0073] The laser processing device 1 of this embodiment is also characterized by further including an analysis unit that acquires the printing speed set in the printing information, and an LCD display 56 that issues a notification urging the user to set to the first mode when the acquired printing speed is greater than a predetermined threshold. If the acquired printing speed is greater than the predetermined threshold, stripes may be noticeable in the filled-in areas, so it is possible to urge the user to set to the first mode to make the stripes less noticeable.

[0074] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0075] (1) In the above embodiment, the liquid crystal display 56 of the print information creation unit 2 is used as an example of the notification unit. However, this is because the laser processing unit 3 does not include a configuration capable of providing a notification. If the laser processing unit 3 includes a configuration capable of providing a notification, such as a display, the display may be made to function as the notification unit.

[0076] (2) In the above embodiment, the laser processing device 1 is configured with a print information creation unit 2 and a laser processing unit 3, but this is not limited to this, and it may be configured as a single unit that includes the functions of the print information creation unit 2 and the functions of the laser processing unit 3. [Explanation of symbols]

[0077] 1...laser processing device, 2...printing information creation unit, 3...laser processing unit, 6...laser controller, 7...object to be processed, 18...galvanometer scanner, 21...laser oscillator, 31...galvanometer X-axis motor, 32...galvanometer Y-axis motor, 37...laser driver, 41...CPU, 42...RAM, 43...ROM, 51...control unit, 55...input operation unit, 56...liquid crystal display, R...processing laser light, S...PWM signal

Claims

1. A laser processing device that processes a workpiece by irradiating the workpiece with laser light based on processing data, a laser oscillator that oscillates the laser light based on an input control signal; a scanning unit that irradiates the oscillated laser light onto the workpiece along a scanning line that advances in a predetermined direction; an output unit that outputs the control signal; a setting unit capable of setting an operation mode; a control unit that controls operations of the scanning unit and the output unit based on the operation mode set by the setting unit; Equipped with The control unit When the first mode is set as the operation mode, the output unit is controlled so that output timings of the control signals are made different between adjacent scanning lines. A laser processing device characterized by:

2. The control unit When the first mode is set, the output unit is controlled so that the output timing of the control signal is made to differ by half a period between adjacent scanning lines.

2. The laser processing device according to claim 1.

3. an analysis unit that analyzes the processing data and determines whether the processing data includes data for performing fill processing on the workpiece; a notification unit that notifies the user to set the first mode when the analysis unit determines that the processing data includes data for filling the workpiece; and 2. The laser processing device according to claim 1, further comprising:

4. an analysis unit that acquires a duty ratio of the control signal; a notification unit that issues a notification to prompt the user to set the first mode when the acquired duty ratio is within a range of 45% to 55%; 2. The laser processing device according to claim 1, further comprising:

5. an analysis unit that acquires a drive frequency of the control signal; a notification unit that issues a notification to prompt the user to set the first mode when the acquired drive frequency is 25 kHz or less; 2. The laser processing device according to claim 1, further comprising:

6. an analysis unit that acquires the linear velocity of the laser light irradiated by the scanning unit on the workpiece; a notification unit that issues a notification to prompt the user to set the first mode when the acquired linear velocity is greater than a predetermined threshold value; 2. The laser processing device according to claim 1, further comprising:

7. an analysis unit that acquires the printing speed set in the processing data; a notification unit that issues a notification to prompt the user to set the first mode when the acquired printing speed is greater than a predetermined threshold value; 2. The laser processing device according to claim 1, further comprising:

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