JP2004354781A - Scanner driving circuit, laser beam machining device and method of adjusting scanner driving circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanner driving circuit or the like in which a high quality drawing is possible even at a higher rotation speed of a scanner. <P>SOLUTION: The scanner driving circuit is provided with: a plurality of mirrors which totally reflects light; a motor which turns mirrors fixed on respective rotation shafts; a scanner driving part 73 for controlling the light to scan a desired direction by driving the motor; a position detection part 75 which detects the turning angle of the mirrors and transmits the angle as positional signals to the scanner driving part 73; a scanner control part 74 for inputting a control signal for controlling the mirrors to a desired turning angle to the scanner driving part 73; and an adjustment mechanism 76 for adjusting the traces of the temporal change of the turning angles of mirrors to be identical for every mirror on the basis of a control signal which is measured on the basis of the control signal outputted from the scanner control part 74 and the positional signals outputted from the position detection part 75. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scanner drive circuit and a method for adjusting the scanner drive circuit. For example, in a laser processing apparatus that performs processing such as printing by irradiating an object to be processed with a laser beam, The present invention relates to a method for adjusting a scanner driving circuit.
[0002]
[Prior art]
The laser processing apparatus scans a laser beam within a predetermined region and irradiates the surface of a processing target (work) such as a component or product with a laser beam to perform processing such as printing or marking. An example of the configuration of the laser processing apparatus is shown in FIG. The laser processing apparatus shown in this figure includes a laser control unit 1, a laser output unit 2, and an input unit 3. The excitation light generated by the laser excitation unit 6 of the laser control unit 1 is irradiated to the laser medium 8 constituting the oscillator by the laser oscillation unit 50 of the laser output unit 2 to cause laser oscillation. The laser oscillation light is emitted from the emission end face of the laser medium 8, the beam diameter is enlarged by the beam expander 53, reflected by the optical member 54, and guided to the scanning unit 9. The scanning unit 9 reflects the laser beam and polarizes it in a desired direction, and the laser beam output from the condensing unit 15 is scanned on the surface of the workpiece W to perform printing or processing.
[0003]
In particular, in recent years, higher speed and higher quality printing capability has been demanded, and the scanning speed of the scanner tends to be increased. The laser processing apparatus includes a scanning unit 9 as shown in FIG. 2 in order to scan the laser output light on the workpiece. The scanning unit 9 includes X / Y-axis scanners 14a and 14b constituting a pair of galvanometer mirrors, and galvano motors 51a and 51b for rotating the galvanometer mirrors fixed to the rotation shafts. The X / Y-axis scanners 14a and 14b are arranged in an orthogonal posture as shown in FIG. 2, and can scan the laser beam by reflecting it in the X and Y directions. Further, a condensing unit 15 is provided below the scanning unit 9. The condensing part 15 is comprised with a condensing lens, and an f (theta) lens is used. As a laser marking device using a galvanometer mirror, there is one as shown in Patent Document 1, for example.
[0004]
A control circuit for driving the scanner configured by such a galvanometer mirror has a configuration as shown in FIG. The circuit shown in this figure includes a scanner 14 including a galvano motor 51 that rotates a galvano mirror, a scanner drive unit 73 that drives the scanner 14, and a scanner control unit 74 that controls the scanner drive unit 73. The scanner control unit 74 includes a power source that sends a control signal to the scanner driving unit 73 and supplies power for driving the scanner driving unit 73. When a control signal is input from the scanner control unit 74, the scanner driving unit 73 drives the scanner 14 based on the control signal. On the other hand, the scanner 14 includes a position detection unit 75 that detects the rotation angle of the rotating galvanometer mirror as a position signal, and feeds back the position signal to the scanner drive unit 73 in real time. The scanner driving unit 73 compares the position signal fed back from the scanner 14 with the control signal input from the scanner control unit 74 and accurately controls the rotation angle of the scanner 14. Each scanner 14 is rotated by such a control circuit.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-8634
[0006]
[Problems to be solved by the invention]
In such a scanner, two galvanometer mirrors are required as shown in FIG. 2 in order to scan the laser light in the X and Y directions. However, the two galvanometer mirrors for the X-axis and the Y-axis cannot be made the same size due to the configuration. For example, when the X-axis scanner 14a receives laser light and reflects it to the Y-axis scanner 14b and the Y-axis scanner 14b outputs laser light, the X-axis scanner 14a always receives the laser light from one direction. And the size of the galvanometer mirror can be small. On the other hand, the Y-axis scanner 14b that receives the light reflected by the X-axis scanner 14a has a wider scanning range of the laser light reflected by the rotation of the X-axis scanner 14a, so a light receiving surface corresponding to the scanning range is prepared. Naturally, the light receiving surface is larger than the X-axis scanner 14a, and the galvanometer mirror is enlarged. On the other hand, if the X-axis scanner 14a is to be enlarged to match the Y-axis scanner 14b, the rotation range of the Y-axis scanner 14b is not separated from the rotation range of the enlarged X-axis scanner 14a. Need to be placed. As a result, the range in which the scanner 14 can be rotated is narrowed, and the range in which the laser beam can be scanned is narrowed. For this reason, the X-axis scanner 14a and the Y-axis scanner 14b cannot be configured as galvano mirrors having the same shape.
[0007]
When the size of the galvanometer mirror of the scanner 14 is different, the moment of inertia (inertia) is also different. When the difference in the moment of inertia of the galvanometer mirror is increased, a difference occurs in the initial response when the scanner 14 is rotated. For example, when a rectangular wave is input as a control signal, a locus in which the rotation angle changes with time when the scanner 14 rises with respect to the control signal is measured as shown in FIG. In the figure, a rectangular wave control signal is indicated by a one-dot chain line, a response locus of the X-axis scanner 14a is indicated by a solid line, and a response locus of the Y-axis scanner 14b is indicated by a broken line. In this way, even when a rectangular wave control signal is input, there is a delay in the stabilization time until both the X-axis scanner 14a and the Y-axis scanner 14b are stabilized at the rotation angle according to the control signal from the trigger input. Here, since the Y-axis scanner 14b has a larger moment of inertia than the X-axis scanner 14a, the locus of rotation is also different.
[0008]
Conventionally, as shown in FIG. 5, the rise time of the X-axis scanner and the Y-axis scanner is adjusted to match the control signal. In order to perform such adjustment, in the circuit shown in FIG. 6, an arbitrary control signal is input to the scanner drive unit 73, and the position signal of the rotation of the scanner 14 corresponding thereto is transmitted from the position detection unit 75 to the scanner drive unit 73. The control signal to the scanner 14, that is, the parameter for controlling the drive current of the galvano motor is adjusted while grasping the rotation of the scanner 14. In this circuit, the parameters of the scanner drive unit 73 are adjusted while checking the waveform with an oscilloscope or the like so that the stabilization time of the X-axis scanner matches that of the Y-axis scanner as shown in FIG. Since conventional scanners have a low rotation speed, that is, drawing is not so fast, such adjustments that match the rise stabilization time maintain the scanner's synchronization, conspicuous in the quality of printed and processed scan results. There was no effect.
[0009]
However, this method has a problem that when the scanner rotates at a high speed, the influence due to the difference in the moment of inertia becomes remarkable, and the scanning is adversely affected. For example, when drawing a circle at high speed with a laser marker, the method of matching the rise time has a large effect due to the difference in the locus of the X-axis scanner and Y-axis scanner with different moments of inertia, and the scanners cannot synchronize and the moment of inertia is reduced. The operation of the Y-axis scanner equipped with a large galvanometer mirror is delayed, and as shown in FIG. 7, the movement distance B of the Y-axis scanner is shorter than the movement distance A of the X-axis scanner, and the circle is drawn as an ellipse. Therefore, the conventional method of adjusting the stabilization time of the rise of the scanner has a problem that the scanning becomes impossible as the rotation speed of the scanner is increased, and the quality of the drawing is deteriorated.
[0010]
The present invention has been made to solve such problems. A main object of the present invention is to provide a scanner driving circuit, a laser processing apparatus, and a method for adjusting a scanner driving circuit that can perform high-quality drawing even when the rotation speed of the scanner is increased.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a scanner drive circuit according to claim 1 of the present invention is a scanner drive circuit that scans a target surface by reflecting light received from outside by rotation of a plurality of mirrors. A plurality of mirrors that totally reflect the light, a motor that rotates the mirrors while being fixed to a rotation shaft, and a scanner drive that controls the motor to drive and scan the light in a desired direction. 73, a position detection unit 75 that detects the rotation angle of the mirror and sends it to the scanner drive unit 73 as a position signal, and a control signal for controlling the mirror to a desired rotation angle is input to the scanner drive unit 73. And a control signal measured based on a control signal output from the scanner control unit 74 and a position signal output from the position detection unit 75. A trajectory which varies the rotational angle of the mirror time against, characterized in that it comprises an adjustment mechanism 76 for adjusting so as to substantially coincide with each mirror each other.
[0012]
With this configuration, synchronization of each mirror is maintained regardless of the scanning speed, that is, the rotational speed of the motor, and high-precision drawing is realized.
[0013]
According to a second aspect of the present invention, there is provided a scanner drive circuit for reflecting a light received from the outside by rotating a pair of mirrors to scan a target surface, and a first mirror for totally reflecting light. A second mirror having a larger moment of inertia than the first mirror, a first motor for rotating the first mirror on a rotating shaft, and a second motor fixed on the rotating shaft. A second motor for rotating the first and second motors, a scanner driving unit 73 for driving the first and second motors to control scanning of light in a desired direction, and the first and second motors. A position detection unit 75 that detects a rotation angle of the mirror and sends it to the scanner drive unit 73 as a position signal, and a control signal for controlling the first and second mirrors to a desired rotation angle are sent to the scanner drive unit 73. Scanner system for input The rotation angle of the first mirror changes with respect to the control signal measured based on the control signal output from the unit 74 and the control signal output from the scanner control unit 74 and the position signal output from the position detection unit 75. And an adjustment mechanism 76 for adjusting the locus so that the rotation angle of the second mirror substantially coincides with the locus of time change with respect to the control signal.
[0014]
With this configuration, even when the scanning speed, that is, the rotational speed of the motor is increased, the first mirror is aligned with the second mirror, and synchronization is maintained, so that highly accurate drawing is realized.
[0015]
Furthermore, the scanner drive circuit according to claim 3 is the scanner drive circuit according to claim 1 or 2, wherein the adjustment mechanism 76 is a variable resistor for adjusting a plurality of parameters for operating the scanner drive unit 73. It is characterized by that.
[0016]
The laser processing apparatus according to claim 4 includes a laser control unit 1 including a laser excitation unit 6 for exciting the laser medium 8 to emit excitation light, and the laser control unit 1 is optically coupled to the laser control unit 1. A laser oscillation unit 50 including a laser medium 8 that is excited by excitation light transmitted from the control unit 1 and emits laser oscillation from an end face, a first mirror that totally reflects light, and a rotation axis of the first mirror. A first motor that is fixed to the first mirror, a second mirror that has a moment of inertia greater than that of the first mirror, and that is arranged with the first mirror and a rotation axis orthogonal to each other, and the second mirror A second motor for rotating the mirror fixed to a rotating shaft, and a scanner driving unit 73 for driving the first and second motors to control scanning in a desired direction, respectively. The first and second mirrors A position detection unit 75 that detects a rotation angle and sends it to the scanner drive unit 73 as a position signal, and a control signal for controlling the first and second mirrors to a desired rotation angle are input to the scanner drive unit 73. And a rotation angle of the first mirror with respect to the control signal measured based on the control signal output from the scanner control unit 74 and the position signal output from the position detection unit 75. And a scanning unit including an adjustment mechanism 76 for adjusting a trajectory in which the rotation angle of the second mirror substantially matches a trajectory in which the rotation angle of the second mirror changes with respect to the control signal, and scanning from the scanning unit 9 And a condensing unit 15 for condensing the light and emitting it as a laser output to the outside.
[0017]
With this configuration, even when the scanning speed of the laser beam, that is, the rotational speed of the motor is increased, the first mirror is aligned with the second mirror, and synchronization is maintained, thereby realizing high-precision drawing.
[0018]
The scanner drive circuit adjustment method according to claim 5 is a scanner drive circuit adjustment method in which light received from the outside is reflected by the rotation of a pair of mirrors to scan the target surface, and the mirror is rotated. A predetermined control signal is input to each motor that rotates while fixing the mirror to the rotation shaft, and is measured by rotating the motor and detecting the rotation angle of the mirror and receiving it as a position signal. A predetermined parameter of the scanner driving unit 73 for driving the motor is set so that a trajectory in which the rotation angle of the mirror with respect to the control signal changes with time is acquired for each mirror, and the measured trajectories substantially coincide with each other. And a step of adjusting.
[0019]
As a result, even when the scanning speed, that is, the rotational speed of the motor is increased, the synchronization of the mirrors is maintained, and high-precision drawing is realized.
[0020]
Further, the scanner drive circuit adjustment method according to claim 6 is the scanner drive circuit adjustment method according to claim 5, wherein the step of adjusting the predetermined parameter of the scanner drive unit 73 is drawn as scanning light. A control signal of a predetermined cycle, which is a trajectory for a trajectory to be reciprocated on a straight line at a predetermined cycle, is input to both motors at the same timing, and a trajectory actually drawn based on this control signal and an original trajectory This is a step of adjusting the parameters so that the difference between the values falls within a predetermined range.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiment exemplifies a scanner drive circuit, a laser processing apparatus, and a scanner drive circuit adjustment method for embodying the technical idea of the present invention. The adjustment method of the laser processing apparatus and the scanner drive circuit is not specified as follows.
[0022]
Further, in this specification, in order to facilitate understanding of the claims, the numbers corresponding to the members shown in the embodiments are referred to as “claim column” and “means for solving the problems”. It is added to the members shown in the column. However, the members shown in the claims are not limited to the members in the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It's just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.
[0023]
A scanner driving circuit according to an embodiment of the present invention is shown in FIG. In this circuit, the scanner 14 includes a galvano mirror which is a total reflection mirror constituting the X-axis scanner 14a and the Y-axis scanner 14b, a galvano motor for rotating with the galvano mirror fixed to the rotation axis, and a rotation axis. Is provided with a position detector 75 for detecting the rotational position of the motor and outputting it as a position signal. The scanner 14 is connected to a scanner driving unit 73 that drives the scanner 14. The scanner driving unit 73 is connected to the scanner control unit 74, receives a control signal for controlling the scanner 14 from the scanner control unit 74, and drives the scanner 14 based on the control signal. For example, the scanner driving unit 73 adjusts the driving current for driving the scanner 14 based on the control signal. Further, the scanner driving unit 73 includes an adjustment mechanism 76 that adjusts a temporal change in the rotation angle of each scanner 14 with respect to the control signal. The adjustment mechanism 76 is composed of a semiconductor component such as a variable resistor that adjusts each parameter of the scanner driving unit 73.
[0024]
The adjustment method of the scanner driving circuit according to the embodiment of the present invention is to adjust the time history of the rotation angle of each scanner with respect to the control signal in the circuit of FIG. In other words, adjustment is performed so that the history of the time when the rotation angle of the X-axis scanner changes with respect to the control signal, that is, the waveform trajectory shown in FIG. 8 matches the waveform trajectory of the Y-axis scanner. That is, it is not an adjustment method that focuses on the rising stabilization time as in the prior art, but is focused on the time change of the rotation angle of each scanner and adjusted so as to match.
[0025]
According to this method, even if the rotation speed of the scanner is increased, the X-axis scanner and the Y-axis scanner change the rotation angle of the scanner along a substantially equal locus, so that synchronization is maintained. For this reason, as in the adjustment method in which only the rise times of the scanners are matched, when the rotation speed of the scanner is increased, the synchronization of the scanner rotation is not maintained, and one rotation is faster or the other rotation is slower. The scan pattern is not distorted. Therefore, even if a circle is drawn by scanning at a high speed, the movement distances in the X-axis direction and the Y-axis direction are maintained substantially equal, and a beautiful circle as shown in FIG. 9 is not distorted into an elliptical shape as shown in FIG. Is drawn. Therefore, according to this method, high-precision drawing can be realized even at high-speed scanning. Such adjustment for matching the locus of the scanner is performed so that the curve of the locus of the X-axis scanner is substantially coincident with that of the Y-axis scanner as shown in FIG. 8 while checking the waveform with an oscilloscope or the like in the circuit of FIG. The parameters are adjusted by the adjusting mechanism 76 of the scanner driving unit 73. In this specification, the X-axis and Y-axis indicate the X-axis and Y-axis at the time of drawing, and it goes without saying that the same effect can be obtained even if these are interchanged.
[0026]
An adjustment method for actually matching the waveform trajectory is performed as follows. First, sine waves synchronized with the X-axis scanner and Y-axis scanner are input, respectively, and the Lissajous waveforms of the position signals of both scanners are observed. Then, as shown in FIG. 10 (a), the image is drawn on the locus of oblique lines that move from the reference point to (1) diagonally up to the right, (2) diagonally down to the left, and (3) diagonally up to the right. In the state where the frequency of the sine wave is low, the image is drawn according to the desired oblique line as described above. However, as the frequency is increased, the waveform gradually collapses and is drawn in a twisted state as shown in FIG. 10B, for example. Is done. Adjustment is performed using the adjustment mechanism 76 of the scanner driving unit 73 so that the broken oblique line falls within a predetermined range. The predetermined range is adjusted so that the actual drawing trajectory falls within this range, for example, with reference to the range of the elliptical width indicated by the broken line in FIG. For example, a sine wave having a frequency of several kHz is input at the maximum rotation speed of the scanner, and the adjustment mechanism 76 is adjusted so that the ratio of the minor axis to the major axis of the ellipse is 1 to 10%.
[0027]
The adjustment work is a procedure in which parameters for determining the operation of the scanner driving unit 73 are adjusted, actual drawing is performed, and the adjustment is further repeated. Parameters for setting such adjustment to adjust the scanner driving unit 73 of each scanner 14, preferably the X-axis scanner to match the Y-axis scanner, include scanner sensor output adjustment, scanner sensor output linearity (left and right) Adjustment), signal input voltage vs. scanner rotation angle, signal input OFF setting (scanner origin adjustment), low frequency damping (speed feedback amount) adjustment, servo gain (addition value of error signal) adjustment There are items such as high-frequency damping (servo acceleration feedback amount) adjustment, high-frequency damping bandwidth adjustment (fine adjustment of servo acceleration feedback amount), center frequency adjustment of notch filter, and attenuation adjustment of notch filter. The adjusting mechanism 76 includes a variable resistor for each of these parameters, and each parameter value is adjusted by changing the value of the variable resistor.
[0028]
As shown in FIG. 8, when adjustment is made so that the waveform trajectories of the X-axis scanner and the Y-axis scanner are matched, for example, even if the scanner is rotated at high speed to draw a circle, the movement distance A and the Y-axis of the X-axis scanner The moving distances B of the scanner are almost equal and drawn as a correct circle. As described above, a desired pattern can be drawn even when the scanner is rotated at high speed, and high-quality printing and processing can be realized.
[0029]
In the example of FIG. 3, the scanner driving unit 73 and the scanner control unit 74 are configured by separate members. However, the configuration is not limited to this configuration. For example, the scanner control unit 74 is integrated with the functions of the scanner control unit 74. It can also be comprised with the member of.
[0030]
[Laser processing equipment]
Next, an example in which the scanner control unit 74 is applied to a laser processing apparatus will be described with reference to FIG. FIG. 1 shows a block diagram of a laser processing apparatus. The laser processing apparatus shown in this figure includes a laser control unit 1, a laser output unit 2, and an input unit 3.
[0031]
Laser processing equipment can be used in general for laser application equipment regardless of its name, such as laser oscillators and various laser processing equipment, laser processing such as drilling, marking, trimming, scribing, surface treatment, and other laser applications as laser light sources. It can be suitably used in the field, for example, a light source for high-density recording / playback of optical discs such as DVD and Blu-ray, a light source for communication, a printing device, a light source for illumination, a light source for a display device such as a display, and a medical device. The following example demonstrates the example applied to a laser marker as an example of a laser processing apparatus. Further, in this specification, “printing” is used in a concept including various kinds of processing described above in addition to marking of characters, symbols, figures and the like.
[0032]
[Input unit 3]
The input unit 3 is connected to the laser control unit 1, inputs necessary settings for operating the laser processing apparatus, and transmits them to the laser control unit 1. The setting contents are operating conditions of the laser processing apparatus, specific printing contents, and the like. The input unit 3 is an input device such as a keyboard, a mouse, or a console. The input unit 3 can also be provided with a display unit for confirming input information and displaying the status of the laser control unit 1 and the like. The display unit is a monitor such as an LCD or a cathode ray tube, and the input unit and the display unit can also be used as a touch panel system. Accordingly, the necessary setting of the laser processing apparatus can be performed at the input unit without externally connecting a computer or the like.
[0033]
[Laser control unit 1]
The laser control unit 1 includes a control unit 4, a memory unit 5, a laser excitation unit 6, and a power source 7. The setting contents input from the input unit 3 are recorded in the memory unit 5. The control unit 4 reads the setting contents from the memory when necessary, and operates the laser excitation unit 6 based on the print signal corresponding to the printing contents to excite the laser medium 8 of the laser output unit 2. The memory unit 5 can use a semiconductor memory such as a RAM or a ROM. The memory unit 5 can be incorporated in the laser control unit 1, or a semiconductor memory card such as a PC card or SD card that can be inserted and removed, or a memory card such as a card-type hard disk. The memory unit 5 composed of a memory card can be easily rewritten by an external device such as a computer. The contents set by the computer are written in the memory card and set in the laser control unit 1 so that the input unit is laser controlled. Settings can be made without connecting to the unit. In particular, a semiconductor memory is fast in reading and writing data and has no mechanical operation part, so it is resistant to vibrations and can prevent data loss accidents due to a crash like a hard disk.
[0034]
Further, the control unit 4 outputs a scanning signal for operating the scanning unit 9 of the laser output unit 2 to the scanning unit 9 in order to scan the workpiece W with the laser light oscillated by the laser medium 8 so as to perform the set printing. To do. The power source 7 applies a predetermined voltage to the laser excitation unit 6 as a constant voltage power source. The printing signal for controlling the printing operation is a PWM signal corresponding to one pulse of the laser beam that is oscillated by switching on / off of the laser beam according to the HIGH / LOW. Although the laser intensity of the PWM signal is determined based on a duty ratio corresponding to the frequency, the laser intensity may be changed depending on the scanning speed based on the frequency.
[0035]
(Laser excitation unit 6)
The laser excitation unit 6 includes a laser excitation light source 10 and a laser excitation light source condensing unit 11 that are optically bonded. An example of the inside of the laser excitation unit 6 is shown in the perspective view of FIG. The laser excitation unit 6 shown in this figure has a laser excitation light source 10 and a laser excitation light source condensing unit 11 fixed in a laser excitation unit casing 12. The laser excitation unit casing is made of a metal such as brass having good thermal conductivity, and efficiently radiates the laser excitation light source 10 to the outside. The laser excitation light source 10 is composed of a semiconductor laser or the like. In the example of FIG. 11, a laser diode array in which a plurality of semiconductor laser diode elements are arranged in a straight line is used, and laser oscillation from each element is output in a line. Laser oscillation enters the incident surface of the laser excitation light source condensing unit 11 and is output as laser excitation light condensed from the emission surface. The laser excitation light source condensing unit 11 is composed of a focusing lens or the like. Laser excitation light from the laser excitation light source condensing unit 11 is incident on the laser medium 8 of the laser output unit 2 through an optical fiber cable 13 or the like. The laser excitation light source 10, the laser excitation light source condensing unit 11, and the optical fiber cable 13 are optically coupled via a space or an optical fiber.
[0036]
[Laser output unit 2]
The laser output unit 2 includes a laser oscillation unit 50. A laser oscillation unit 50 that generates laser light includes a laser medium 8, an output mirror and a total reflection mirror that are arranged to face each other at a predetermined distance along an optical path of stimulated emission light emitted from the laser medium 8, and Apertures, Q switches, etc. are provided between them. The stimulated emission light emitted from the laser medium 8 is amplified by multiple reflection between the output mirror and the total reflection mirror, and the mode is selected by the aperture while being cut off in a short period by the operation of the Q switch, and the output mirror After that, the laser beam is output. The laser output unit 2 illustrated in FIG. 1 includes a laser medium 8 and a scanning unit 9. The laser medium 8 is excited by the laser excitation light incident from the laser excitation unit 6 via the optical fiber cable 13 and is oscillated. The laser medium 8 employs a so-called end pumping excitation system in which laser excitation light is input from one end face of a rod shape and is excited, and laser light is emitted from the other end face.
[0037]
(Laser medium 8)
In the above example, the rod-shaped Nd: YVO is used as the laser medium 8. ₄ The solid laser medium was used. The wavelength of the semiconductor laser for exciting the solid laser medium is Nd: YVO. ₄ The center wavelength of the absorption spectrum of 809 nm was set to 809 nm. However, the present invention is not limited to this example, and other solid-state laser media such as rare earth-doped YAG, LiSrF, LiCaF, YLF, NAB, KNP, LNP, NYAB, NPP, and GGG can also be used. Further, the wavelength conversion element can be converted into an arbitrary wavelength by combining a wavelength conversion element with a solid laser medium.
[0038]
Furthermore, it is also possible to use a wavelength conversion element that does not use a solid laser medium, in other words, does not constitute a resonator that oscillates laser light, and performs only wavelength conversion. In this case, wavelength conversion is performed on the output light of the semiconductor laser. As the wavelength conversion element, for example, KTP (KTiPO ₄ ), Organic nonlinear optical materials and other inorganic nonlinear optical materials such as KN (KNbO) ₃ ), KAP (KAsPO ₄ ), BBO, LBO, and bulk type polarization inversion elements (LiNbO) ₃ (Periodically Pollected Lithium Niobate: PPLN), LiTaO ₃ Etc.) are available. Further, a semiconductor laser for an excitation light source of a laser by up-conversion using a fluoride fiber doped with rare earth such as Ho, Er, Tm, Sm, and Nd can be used. Thus, in this embodiment, various types can be appropriately used as a laser generation source.
[0039]
(Scanning unit 9)
The scanning unit 9 reflects the laser beam and outputs it in a desired direction, scans the laser beam on the surface of the workpiece W, and prints it. As shown in FIG. 2, the scanning unit 9 includes a pair of an X-axis scanner 14a and a Y-axis scanner 14b, and galvano motors 51a and 51b that rotate them. The galvano motors 51 a and 51 b are driven by the scanner drive circuit 52. The scanner driving circuit 52 drives the galvano motors 51a and 51b based on the scanning signal supplied from the control unit 4, thereby causing the X-axis scanner 14a and the Y-axis scanner 14b provided on the output shafts of the galvano motors 51a and 51b. The total reflection mirror is rotated to deflect and scan the laser beam oscillated from the laser medium 8. The laser beam that has been deflected and scanned is irradiated and marked on the surface of the workpiece W through an fθ lens provided substantially in the deflection direction. The fθ lens is provided so that the laser beam deflected in a state where the scanner is in the neutral position is incident on the center as parallel light.
[0040]
[Condenser 15]
The condensing unit 15 uses a condensing lens such as an fθ lens. After the laser beam is reflected by the galvanometer mirror, the laser beam is condensed by the condensing lens and irradiated on the irradiation surface. However, in order to effectively condense the small spot, the galvanometer mirror is used as shown in FIG. A beam expander 53 is provided in front of the laser beam generator 50 so that the beam diameter of the laser beam output from the laser oscillation unit 50 is expanded. The outgoing beam from the beam expander 53 is reflected by an optical member 54 such as a mirror and guided to the galvanometer mirror of the scanning unit 9.
[0041]
As described above, by applying the scanner driving circuit adjustment method to the laser processing apparatus, the printing quality has been improved by about 20 to 30% even with the same configuration as the conventional one. In addition, this adjustment method can be implemented simply by changing the control method while using the existing scanner drive circuit without adding new hardware. There is a merit that a high effect of improving markedly can be obtained.
[0042]
【The invention's effect】
As described above, according to the scanner drive circuit, the laser processing apparatus, and the scanner drive circuit adjustment method of the present invention, it is possible to perform highly accurate drawing without changing the quality even during high-speed scanning only by changing the control method of the scanner. It becomes. The scanner drive circuit, the laser processing apparatus, and the scanner drive circuit adjustment method of the present invention focus on the trajectory of the time change rather than the stable time at the start of the scanner adjustment so that the waveform patterns of the scanners match. Because it is adjusted to. With this method, not only low-speed scanning but also high-speed scanning can suppress the synchronization shift caused by the difference in the moment of inertia of the mirror, and can obtain a scanning pattern with high accuracy, increasing the scanning speed of the scanner. High-quality high-speed printing and high-speed processing can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a laser processing apparatus according to an embodiment of the present invention.
FIG. 2 is a transparent perspective view showing an arrangement state of an X / Y-axis scanner in a scanning unit.
FIG. 3 is a block diagram illustrating an example of a scanner drive circuit.
FIG. 4 is a graph showing a change over time of the rotation angle of the scanner based on a control signal.
FIG. 5 is a graph showing an example in which the stabilization time at the time of startup of the scanner is adjusted to match in FIG. 4;
6 is a block diagram illustrating a method for adjusting the scanner driving circuit of FIG. 3; FIG.
7 is a schematic diagram showing an actual drawing result when the scanner scans at a high speed so as to draw a circle in the adjustment method of FIG. 5;
FIG. 8 is a graph showing an example in which the scanner drive circuit adjustment method according to an embodiment of the present invention is adjusted so that the time-varying trajectory of the scanner rotation angle is matched.
FIG. 9 is a schematic diagram showing an actual drawing result when the scanner is scanned at a high speed so as to draw a circle in the scanner driving circuit adjustment method according to the embodiment of the present invention;
FIG. 10 is a schematic diagram illustrating an example of a method for adjusting a scanner driving circuit according to an embodiment of the present invention.
11 is a perspective view showing an example of the internal structure of the laser excitation unit in FIG. 1. FIG.
[Explanation of symbols]
1 ... Laser controller
2 ... Laser output section
3 ... Input section
4. Control unit
5 ... Memory part
6 ... Laser excitation part
7 ... Power supply
8 ... Laser medium
9 ... Scanning section
10 ... Laser excitation light source
11 ... Laser excitation light source condensing part
12 ... Laser excitation part casing
13 ... Optical fiber cable
14 ... Scanner
14a ... X-axis scanner
14b ... Y-axis scanner
15 ... Condensing part
50 ... Laser oscillator
51, 51a, 51b ... Galvano motor
52. Scanner drive circuit
53 ... Beam expander
54. Optical member
73 ... Scanner drive unit
74 ... Scanner control unit
75 ... Position detector
76 ... Adjustment mechanism

Claims (6)

A scanner driving circuit that reflects light received from outside by rotating a plurality of mirrors and scans a target surface;
A plurality of mirrors that totally reflect light;
A motor for rotating each of the mirrors on a rotation shaft;
A scanner drive unit (73) for driving the motor and controlling the light to scan in a desired direction;
A position detection unit (75) for detecting a rotation angle of the mirror and sending it as a position signal to the scanner drive unit (73);
A scanner control section (74) for inputting a control signal for controlling the mirror to a desired rotation angle to the scanner drive section (73);
A trajectory in which the rotation angle of the mirror changes with respect to the control signal, measured based on the control signal output from the scanner controller (74) and the position signal output from the position detector (75), An adjustment mechanism (76) for adjusting the mirrors to substantially match each other;
A scanner driving circuit comprising: A scanner driving circuit that reflects light received from outside by rotating a pair of mirrors and scans a target surface;
A first mirror that totally reflects light;
A second mirror having a greater moment of inertia than the first mirror;
A first motor for rotating the first mirror fixed to a rotating shaft;
A second motor for rotating the second mirror fixed to a rotating shaft;
A scanner driving unit (73) for controlling the first and second motors to drive the light in a desired direction;
A position detection unit (75) that detects a rotation angle of the first and second mirrors and sends it to the scanner drive unit (73) as a position signal;
A scanner control unit (74) for inputting a control signal for controlling the first and second mirrors to a desired rotation angle to the scanner drive unit (73);
The rotation angle of the first mirror changes with respect to the control signal measured based on the control signal output from the scanner control unit (74) and the position signal output from the position detection unit (75). An adjustment mechanism (76) for adjusting the trajectory so that the rotation angle of the second mirror substantially coincides with the trajectory of the time change with respect to the control signal;
A scanner driving circuit comprising: 3. The scanner driving circuit according to claim 1, wherein the adjusting mechanism (76) is a variable resistor for adjusting a plurality of parameters for operating the scanner driving unit (73). . A laser control unit (1) including a laser excitation unit (6) for exciting the laser medium (8) to emit excitation light;
A laser oscillation unit (50) comprising a laser medium (8) optically coupled to the laser control unit (1), excited by excitation light transmitted from the laser control unit (1), and emitting laser oscillation from an end face. When,
A first mirror that totally reflects light;
A first motor for rotating the first mirror fixed to a rotating shaft;
A second mirror having a moment of inertia greater than that of the first mirror and disposed so that the first mirror and the rotation axis are orthogonal to each other;
A second motor for rotating the second mirror fixed to a rotating shaft;
A scanner driving unit (73) for controlling the first and second motors to drive the light in a desired direction;
A position detection unit (75) that detects a rotation angle of the first and second mirrors and sends it to the scanner drive unit (73) as a position signal;
A scanner control unit (74) for inputting a control signal for controlling the first and second mirrors to a desired rotation angle to the scanner drive unit (73);
The rotation angle of the first mirror changes with respect to the control signal measured based on the control signal output from the scanner control unit (74) and the position signal output from the position detection unit (75). An adjustment mechanism (76) for adjusting the trajectory so that the rotation angle of the second mirror substantially coincides with the trajectory of the time change with respect to the control signal;
A scanning unit (9) comprising:
A condensing part (15) for condensing the scanning light from the scanning part (9) and emitting it as a laser output;
A laser processing apparatus comprising: A method for adjusting a scanner driving circuit that scans a target surface by reflecting light received from the outside by turning a pair of mirrors,
By inputting a predetermined control signal for rotating the mirror to each motor that rotates the mirror while fixing the mirror to the rotation shaft, the motor is rotated, and the rotation angle of the mirror is detected and received as a position signal. Obtaining a trajectory for each mirror, which is measured, and a time-varying change in the rotation angle of the mirror with respect to the control signal;
Adjusting a predetermined parameter of the scanner drive unit (73) for driving the motor so that the measured trajectories substantially coincide with each other between the mirrors;
A method for adjusting a scanner driving circuit, comprising: 6. The method of adjusting a scanner driving circuit according to claim 5, wherein the step of adjusting a predetermined parameter of the scanner driving unit (73) comprises:
A control signal of a predetermined cycle, which is a trajectory to be drawn as scanning light in a predetermined cycle on a straight line, is input to both motors at the same timing, and a trajectory actually drawn based on this control signal, A method for adjusting a scanner driving circuit, characterized in that it is a step of adjusting parameters so that a difference from an original trajectory falls within a predetermined range.

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