JP2003329960A - Method and device for controlling galvanoscanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration in positioning precision and a coil burning due to motor coil heat generation of a galvanoscanner while minimizing a decrease in throughput. <P>SOLUTION: Based on the state of variation of a driving signal, a state wherein an error due to the heat generation of a motor coil is about to occur is detected and the driving state is changed to suppress the heat generation of the motor coil. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method and apparatus for a galvano scanner which drives a mirror by a motor to scan a laser irradiation position, and more particularly to a method for irradiating a laser beam to form a plurality of holes in a printed wiring board or the like. Galvano scanner control that is suitable for use in laser drilling machines that perform drilling and that can prevent deterioration of positioning accuracy and burnout of the coil due to heat generation in the motor coil of the galvano scanner while minimizing the decrease in throughput. A method and apparatus.

[0002]

2. Description of the Related Art A method of moving an irradiation position with a galvano scanner when processing with a laser is adopted.
High-speed processing is possible.

FIG. 1 is a structural example of a general laser drill machine. In this configuration example, a first galvanometer including a first mirror 15 for scanning, for example, a pulsed laser beam 11 emitted from a laser oscillator (not shown) in a predetermined direction (a direction perpendicular to the paper surface in FIG. 1). The scanner 14 and the laser beam 12 scanned by the first galvano scanner 14 in the direction perpendicular to the paper surface are scanned in the direction perpendicular to the scanning direction by the first galvano scanner 14 (direction parallel to the paper surface in FIG. 1). Second including a second mirror 17 for
The galvano scanner 16 and the f-θ lens 18 for deflecting the laser beam 13 scanned in two directions by the first and second galvano scanners 14 and 16 in a direction perpendicular to the surface of the object to be processed 10. It has and.

In this galvano scanner, the laser beam 11 output from a laser oscillator (not shown)
After being reflected by the mirror 15 and the second mirror 17, it passes through the f-θ lens 18 and is focused on the object to be processed 10. First
The mirror 15 and the second mirror 17 can be rotated in different directions, and by changing the rotation angle of these mirrors (simply referred to as an angle or a mirror angle), the laser beam can be moved to any position on the processing object 10. It can be processed by irradiating it.

Since a high throughput is required for drilling a substrate or the like, a galvano scanner capable of performing high-speed processing by moving a laser beam is used as compared with the method of moving the object to be processed 10. Often used.

The control device 30 of the galvano scanners 14 and 16 as described above, for example, as shown in FIG. / A converter 40, feedback controller 42, power amplifier 4
4, an in-position determination unit 46, a heat generation amount calculation unit 48, and an error detection unit 50.

Such a galvano scanner controller 30
At the mirror 15 of the Galvano scanners 14 and 16,
The target angle of 17 is input to the command value generator 32 from a host controller (not shown). This command value is D /
The A converter 40 converts the analog command voltage into an analog command voltage, which is input to the feedback controller 42.

On the other hand, the angle of the mirror 15 or 17 is measured by the angle sensor 20 attached to the galvano scanners 14 and 16 and input to the feedback control section 42.

In the feedback control section 42, the D /
A current command is output based on the command voltage input from the A converter 40 and the measurement angle signal input from the angle sensor 20. The power amplifier 44 produces a drive current according to this current command, which drives a motor (not shown) of the galvano scanner 14 or 16 and causes the mirror 15 or 17 to rotate.

The in-position determination section 46 generates an in-position signal indicating whether the angle of the mirror 15 or 17 is within a preset settling range based on the deviation signal from the feedback control section 42. .

Further, the heat generation amount calculation unit 48 calculates the heat generation amount based on the drive current output from the power amplifier 44, and the error detection unit 50 will be described in detail later based on this. The method produces an error signal.

The in-position signal and the error signal are input to the positioning completion judging section 34. In addition,
The error signal is also input to the feedback control unit 42.

The positioning completion judgment unit 34 judges the positioning completion based on the input signal and outputs the positioning completion signal to the host controller.

It should be noted that the applicant has already filed a patent application 20 that the command value generating section 32 and the positioning completion determining section 34 are configured by a digital computer to enable complicated conditional branching.
01-210834 is proposed.

The error detecting section 50 is intended to prevent the temperature of the galvano scanner from rising. That is, when the temperature of the motor coil rises, thermal deformation, temperature drift of the angle sensor 20 and the like occur, the positioning accuracy is deteriorated, and the motor coil may be burned.

The calorific value calculating section 48 calculates the calorific value of the motor coil based on the driving current within a predetermined time, and the calculated calorific value is input to the error detecting section 50. The error detection unit 50 monitors whether or not the calculated heat generation amount exceeds a preset value (hereinafter referred to as a limit value) L, and if it exceeds, outputs an error signal.

Here, conditions under which an error is likely to occur will be examined. First, FIG. 3 shows an example of the relationship between the movement amount and the waveform outline of the drive current for the three movement amounts of small, medium, and large. Here, when the movement amount is small (A), the driving current is small at the time of acceleration, and the vehicle is decelerating with almost no uniform speed. If the amount of movement is medium (B),
At the time of acceleration, the driving current is large, and as in (A), the speed is decelerating without becoming almost constant. Further, when the amount of movement is large (C), the drive current during acceleration / deceleration is large as in the case of (B), but the constant velocity time during which almost no current flows is long. The small, medium, and large movements here are:
For example, the distance on the processed surface is 0.5 mm, 2 mm, 5 mm, or the like.

A summary of these relationships is shown in FIG. The heat generation amount of the motor coil is determined by the magnitude of the drive current and the duty (the ratio of the current flowing during a certain period). Looking at this for one movement, the amount of heat generation is highest when the amount of movement is medium. However, in the calorific value calculation unit 48, a time sufficiently longer than one movement is set as the predetermined time, and the drive current within that time is the target of the calorific value evaluation. Therefore, there is a high possibility that an error will occur when the above conditions continue. For example, as shown in the image of the time change of the calculated heat generation amount as shown in FIG. 5, if the above condition continues for a long time, the calculated heat generation amount reaches the limit value L of the error detection unit 50, which causes an error.

In actual substrate processing, since the movement amount changes discontinuously and there are many small movements, the possibility that the above conditions are continuous is extremely low, but it cannot be said to be zero.

Conventionally, (1) when the error occurs, the feedback control unit 42 turns off the servo, provides a current pause period, and restores (servo ON) after a set time, while the error occurs, the positioning completion signal is generated. (2) The feedback control unit 42 in which the drive power is suppressed to a small value so that an error does not occur even if the above conditions continue.
And the adjustment of the command value were performed.

[0021]

[Problems to be Solved by the Invention] However, (1)
In the case of, as shown in FIG. 5, the mirror operation cannot be guaranteed,
Since the mirror angle becomes indefinite, there is a possibility that the mirrors may be damaged by the collision, particularly in a device in which the two mirrors 15 and 17 may interfere with each other depending on the angle.

Further, in the case of (2), the maximum acceleration is reduced under all conditions, which causes a decrease in throughput.

Incidentally, Japanese Patent Laid-Open No. 2001-228414 discloses that
It is described that the characteristic variation of the position sensor is detected by the variation of the integrated value of the current flowing through the galvanometer, and the signal to warn the necessity of the correction work for the characteristic variation is output. It was not something to take measures against.

The present invention has been made to solve the above-mentioned conventional problems, and it is an object of the present invention to prevent deterioration of positioning accuracy and burnout of a coil due to heat generation of a motor coil of a galvano scanner while minimizing a decrease in throughput. And

[0025]

According to the present invention, in a control method of a galvano scanner in which a mirror is driven by a motor to scan a laser irradiation position, an error caused by heat generation of a motor coil is generated based on a change state of a drive signal. The problem is solved by detecting a close state and changing the driving state to suppress heat generation of the motor coil.

Further, the state in which the error is close to occurrence is detected because the state in which the driving signal is large during acceleration and the vehicle is decelerating with almost no uniform speed continues.

Further, the state in which the error occurs is set to a level at which the error does not occur due to the heat generation of the motor coil even if the next movement is performed.

Further, the next movement is stopped when a state in which the error is about to occur is detected.

Alternatively, the rate of change of the next command value is reduced when a state in which the error is about to occur is detected.

Further, an error occurrence state due to the heat generation of the motor coil is detected and the drive state is changed to prevent the trouble due to the heat generation of the motor coil.

According to the present invention, in a control device for a galvano scanner that drives a mirror by a motor to scan a laser irradiation position, a state in which an error due to heat generation of a motor coil is near is detected based on a change state of a drive signal. The problem is solved by providing a means for controlling and a means for suppressing heat generation by changing the driving state when a state in which the error is close to being detected is detected.

According to the present invention, in a control device of a galvano scanner which drives a mirror by a motor to scan a laser irradiation position, a state in which an error due to heat generation of a motor coil is near based on a change state of a drive signal, and , A means for detecting an error occurrence state, and a means for changing the driving state to suppress heat generation of the motor coil or prevent a failure due to heat generation when a state close to the error occurrence or an error occurrence state is detected. By providing, the said subject was solved.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

In the embodiment of the present invention, in addition to the error detection section (hereinafter referred to as the first error detection section) 50 in the laser control device 30 as shown in FIG. A second error detection unit 5 that generates a warning signal at a second limit value L2 that is lower than the limit value L set by the detection unit 50 (hereinafter referred to as the first limit value L1).
2 is provided so that the command value generated by the command value generation unit 32 is changed when the warning signal is output from the second error detection unit 52.

The other points are the same as those in FIG. 2 including the heat generation amount calculating section 48, and therefore detailed description will be omitted.

When the state is close to the occurrence of an error, the second
When a warning signal is output from the error detection unit 52 of, the following processing is performed.

FIG. 7 shows the time change of the calculated calorific value in the first embodiment of the present invention. The second error detector 5
From 2, a warning signal is output when the calculated heat generation amount reaches the limit value L2. Therefore, in the first embodiment, when the warning signal is output, the calculated heat generation amount is reduced by not performing (delaying) the next movement as shown in FIG. 7.

Specifically, the positioning completion judging section 34
Does not output the positioning completion signal when it detects the warning signal. Further, the command value generation unit 32 does not output the command value when the warning signal is detected. However, when the output is in progress, if the output is stopped midway, the positioning may not be performed promptly, so it is better not to stop the output of the designated value in the middle. Therefore,
The warning signal is monitored before output.

Since a warning signal may be output during the output of the command value as described above, the limit value L2 is set even if the movement is performed about once after the warning signal is output. The value is set so that it does not reach the value L1.

Next, FIG. 8 shows the time change of the calorific value calculated in the second embodiment of the present invention. In the present embodiment, when the calculated calorific value reaches the limit value L2 and the warning signal is output from the second error detection unit 52, the magnitude and duty of the drive current are reduced, so that as shown in FIG. The calculated calorific value is reduced by changing the slope of the command value.

Specifically, the command value generator 32 reduces the rate of change of the command value when the warning signal is detected. However, if the command value is being output, it may not be possible to quickly perform positioning if changed midway, so it is better not to change the command value output midway. Therefore, the warning signal is monitored before output.

Since a warning signal may be output during the output of the command value as described above, the limit value L2 is set even if the normal movement is performed about once after the warning signal is output. , So that the limit value L1 is not reached.

By the method as described above, it is possible to prevent the temperature rise of the motor coil of the galvano scanner while minimizing the decrease in throughput.

In each of the above-described embodiments, the limit value L1 similar to the conventional one based on the output of the calorific value calculation unit 48 is used.
Since the monitoring by the limit value L2 according to the present invention is added to the monitoring by, the configuration is simple and the safety is high. It should be noted that it is possible to omit monitoring by the limit value L1 if it is possible to detect that the state of FIG. 3B is continuous by another method or if sufficient reliability can be obtained by monitoring by the limit value L2. Is.

In the above embodiment, the present invention is applied to the laser drill machine, but the application target of the present invention is not limited to this, and if a galvano scanner is used, for example, a marking machine, etc. It is obvious that the same can be applied to the machine of.

[0046]

According to the present invention, it is possible to prevent deterioration in positioning accuracy and burnout of the coil due to heat generation in the motor coil of the galvano scanner while minimizing the decrease in throughput.

[Brief description of drawings]

FIG. 1 is a front view showing a main configuration of a laser drill machine which is an example of an application target of the present invention.

FIG. 2 is a block diagram showing a configuration example of a conventional control device for a galvano scanner.

FIG. 3 is a diagram showing an example of a relationship between a movement amount and a drive current in a conventional galvano scanner.

FIG. 4 is a diagram showing a relationship between driving time / driving current and heat generation amount of each movement amount in one movement.

FIG. 5 is a diagram similarly showing an example of temporal changes in calculated calorific value.

FIG. 6 is a block diagram showing a configuration of an embodiment of a galvano scanner control device according to the present invention.

FIG. 7 is a diagram showing an example of temporal changes in the calculated heat generation amount according to the first embodiment of the present invention.

FIG. 8 is a diagram showing an example of a temporal change in the calculated heat generation amount according to the second embodiment of the present invention.

[Explanation of symbols]

14, 16 ... Galvano scanner 15, 17 ... Mirror 20 ... Angle sensor 30 ... Control device 32 ... Command value generation unit 34 ... Positioning completion determination unit 40 ... D / A converter 42 ... Feedback control unit 44 ... Power amplifier 46 ... In-position determination unit 48 ... Calorific value calculation unit 50, 52 ... Error detection unit L, L1, L2 ... Limit value

Continued front page    (72) Inventor Yasuyuki Okuhira             Sumitomo Heavy Industries, No. 15-15 Kyoritsutsumi, Hiratsuka City, Kanagawa Prefecture             Machine Industry Co., Ltd. Hiratsuka Office F-term (reference) 2H045 AB03 AB34 AB48 AB54 DA41                 4E068 AF00 CA18 CB01 CD11 CE02                       DA11

Claims (8)

[Claims] 1. A method for controlling a galvano scanner which scans a laser irradiation position by driving a mirror by a motor, detects a state in which an error due to heat generation of a motor coil is near based on a change state of a drive signal, and drives the state. Is controlled to suppress heat generation of the motor coil, a method for controlling a galvano scanner. 2. The galvanometer according to claim 1, wherein the state in which the error is close to occurrence is detected from a state in which the drive signal is large during acceleration and the state of deceleration continues with almost no uniform speed. How to control the scanner. 3. The galvano scanner according to claim 1 or 2, wherein the state in which the error occurs is set to a level at which the error does not occur due to heat generation of the motor coil even when the next movement is performed. Control method. 4. The next movement is stopped when a state near the occurrence of the error is detected.
The method for controlling the galvano scanner according to any one of 1. 5. The control method for a galvano scanner according to claim 1, wherein the rate of change of the next command value is reduced when a state in which the error is about to occur is detected. 6. A method of controlling a galvano scanner according to claim 1, further comprising detecting an error occurrence state due to heat generation of the motor coil and changing a driving state to prevent a trouble due to heat generation of the motor coil. . 7. A control device for a galvano scanner that drives a mirror by a motor to scan a laser irradiation position, and means for detecting a state in which an error due to heat generation of a motor coil is near based on a change state of a drive signal, A control device for a galvano scanner, comprising: a means for changing a driving state to suppress heat generation of a motor coil when a state in which an error is about to occur is detected. 8. A control device for a galvano scanner that drives a mirror by a motor to scan a laser irradiation position, in which an error due to heat generation of a motor coil is close to an error occurrence state based on a change state of a drive signal. And a means for suppressing the heat generation of the motor coil or preventing a failure due to the heat generation by changing the driving state when the state close to the error occurrence or the error occurrence state is detected. Control device for galvano scanner characterized by.