JP3513489B2 - Galvano scanner control method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling a galvano scanner for moving the irradiation position of a laser beam, and more particularly to a laser for irradiating a laser beam to make a plurality of holes in a printed circuit board wiring or the like. The present invention relates to a galvano scanner control method and apparatus suitable for use in a drill machine.

[0002]

2. Description of the Related Art When a laser beam is used for machining, a galvano scanner is used to move the irradiation position.
High-speed processing is possible.

FIG. 1 is a structural example of a general laser drill machine. This configuration example is, for example, a pulsed laser beam 12 emitted from a laser oscillator (not shown).
The first galvanometer scanner 14 including a mirror 15 for scanning in a predetermined direction (a direction perpendicular to the paper surface in FIG. 1).
In order to scan the laser beam 12 scanned by the first galvano scanner 14 in the direction perpendicular to the paper surface in a direction perpendicular to the scanning direction by the first galvano scanner 14 (direction parallel to the paper surface in FIG. 1). Second galvano-scanner 16 including the mirror 17 and f for polarizing the laser beam scanned in two directions by the first and second galvano-scanners 14 and 16 in a direction perpendicular to the surface of the workpiece 10. And a -θ lens 18.

In this galvano scanner, the laser beam 1 is generated by the first and second galvano scanners 14 and 16.
2 can be moved to any position on the surface of the object to be processed 10. When the laser beam deflected by the mirrors 15 and 17 passes through the f-θ lens 18, the workpiece 1 is processed.
Focus on the 0 surface. Therefore, by controlling the two galvano scanners 14 and 16, it is possible to perform laser processing on an arbitrary portion of the surface of the processing object 10.

Since a high throughput is required for drilling a substrate or the like, a galvano scanner capable of high-speed processing by moving a laser beam is used as compared with the method of moving the object to be processed 10. Often. In this case, since the positioning speed of the galvano scanner directly affects the throughput, increasing the speed is an important issue.

When performing high-speed control, the control device is generally realized by an analog circuit. Since the control of the galvano scanner is also high speed, the conventional control device has been realized by an analog circuit.

[0007]

However, while the analog circuit is capable of high-speed processing, it is not suitable for processing such as complicated arithmetic operations, conditional branching, and parameter switching.
It has a problem that only simple control can be realized. Therefore, although the control method for improving the driving characteristics of the galvano scanner is known, it may not be realized because it includes complicated processing that cannot be configured by an analog circuit.

For example, in the conventional method, when a small angle is designed to be driven with a large current at a high speed, when driving a large angle, deterioration of characteristics due to current saturation or failure due to overcurrent may occur. On the other hand, if the design is such that the current is suppressed even when driving a large angle, driving at a small angle will not be able to exert sufficient force, and it will take time to settle the mirror.

When a computer is used as the host system, the angle command to the galvano scanner may be issued by a digital signal. In this case, simply D
The signal is A / A-converted and input to the analog circuit, and no digital calculation was performed to improve controllability.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to realize complicated processing at high speed.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a method of controlling a galvano scanner for moving the irradiation position of a laser beam, wherein a constant acceleration of
The above problem is solved by generating a command value of a waveform in which a triangular wave is superimposed on an acceleration / deceleration pattern and performing feedback control for the command value by an analog circuit. The present invention also changes the irradiation position of the laser beam.
In the control method of the galvano scanner for
It is commonly used to generate a command value waveform with a digital calculator.
In addition, set the initial value that determines the magnitude of the current for starting
Feedback control for the command value
The above problem is solved by using an analog circuit.
And improved the acceleration characteristics at the start of driving,
This enables high speed driving.

The present invention also provides a control device for a galvano scanner for moving a laser beam irradiation position,
Triangular wave is superimposed on the acceleration / deceleration pattern of constant acceleration
The above problem is also solved by providing a digital calculator for generating a command value of a waveform and an analog circuit for performing feedback control with respect to the command value.

[0013]

[0014]

The triangular wave is a waveform that once increases and then decreases, thereby compensating for the delay with respect to the command value and applying the current more efficiently to enable higher speed driving.

Further, the triangular wave has a waveform that monotonically decreases from the initial value to improve the acceleration characteristic at the start of driving and enable higher speed driving.

The present invention also sets the irradiation position of the laser beam.
In the control device of the galvano scanner for moving,
Generates the waveform of the command value, and at the same time
The initial value that determines the
Digital calculator and feedback control for the command value
By providing an analog circuit for controlling
In addition to solving the above problem , the acceleration characteristic at the start of driving is improved, and higher speed driving is possible. Also, the digital
Waveform that accelerates and decelerates at a constant acceleration by a calculator
By generating the command value of
The mirror can be driven efficiently.

[0018]

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 present embodiment, as shown in FIG. 2, a digital calculator 30 which calculates a command value according to a target angle of the mirror 20 input from a higher-order system (not shown) and generates a waveform of the command value. And a D / A for converting the command value output from the digital calculator 30 into an analog command voltage
Measured angle of the mirror input from the converter 32, the analog command voltage input from the D / A converter 32, and the angle sensor 24 for detecting the rotation angle of the mirror 20 driven by the motor 22. An analog circuit 34 that outputs a current command from a signal, and a power amplifier 36 that drives a motor 22 by generating a drive current according to the current command input from the analog circuit 34 are configured.

The target rotation angle of the mirror 20 is input to the digital calculator 30 from a higher-level system (not shown). The digital calculator 30 calculates a command value according to the target angle. The calculation result is the D / A converter 32.
Is input to the analog circuit 34 as an analog command voltage.

On the other hand, the angle of the mirror 20 is determined by the angle sensor 2
4 and is input to the analog circuit 34.

The analog circuit 34 outputs a current command from the command voltage and the measurement angle signal. The power amplifier 36 creates a current according to the current command, which drives the motor 22 and rotates the mirror 20.

In this way, by combining the digital calculator 30 and the analog circuit 34, it is possible to realize high-speed and high-level control. That is, high-level processing can be realized by performing feedback control that requires high-speed processing in the analog circuit 34 and generating a command value that does not matter at a relatively low speed in the digital calculator 30.

[0024]

EXAMPLES First, the simulation results of the conventional method will be described. FIG. 3 is a simulation result when the galvano scanner is controlled by the conventional method. The target angle (dotted line A), the actual mirror angle (solid line B), and the drive current (solid line D) are plotted. is there. As is clear from FIG. 3, a large output D1 is found in the drive current, but this problem could not be solved by the conventional method.

Next, the simulation result of the method according to the present invention will be described. FIG. 4 shows a digital calculator 30.
The target angle A, the command value C, and the mirror angle in the first example of the present invention in which the command value (broken line C) of the S-shaped pattern for accelerating and decelerating at a certain speed is calculated by B and drive current D are plotted respectively. At this time, the feedback loop is a controller such as a PID composed of an analog circuit, and although it is a simple control method, high-speed processing is realized.

From FIG. 4, it is understood that by giving a command value with a constant acceleration, it is possible to efficiently move the mirror while keeping the maximum current constant. Therefore, if the limitation on the current is the same, the driving speed is improved.

It is difficult to generate such a pattern by an analog circuit, but if a digital calculator is used,
It can be calculated easily. Also, from this result, if the feedback loop is processed at high speed by the analog circuit,
It can be seen that the galvano scanner can be driven at high speed even if the command value generation cycle is relatively low.

Next, as a command value, as in the first example,
As shown in the middle part of FIG. 5, a waveform C ′ is added to a S-shaped waveform C that accelerates and decelerates at a constant speed, and a triangular wave E that monotonically increases during the acceleration and monotonically decreases during the deceleration. FIG. 5 shows the target angle A, the command value C ′, the mirror angle B, and the drive current D in the second example of the invention.

In this way, when a triangular wave that monotonically increases during acceleration and monotonically decreases during deceleration is added, D in FIG.
As shown in FIG. 3, compared with D2 of FIG. 4, it becomes possible to compensate for the delay with respect to the command value and to speed up the settling of the galvano scanner, so that the current is applied more efficiently, and higher speed driving is possible. Become. An example of adding a triangle wave is
This is effective when the analog circuit is an I-PD controller.

In addition to the second example, as shown in the middle part of FIG. 6, a waveform C is obtained by adding a waveform F that takes a certain initial value from the start of the command and decreases monotonically during acceleration and becomes 0. ″
FIG. 6 shows the relationship among the target angle A, the command value C ″, the mirror angle B, and the drive current D in the third example of the present invention in which is given as the command value.

In this way, by taking a certain initial value from the start of the command and adding a waveform F that monotonically decreases during acceleration and becomes 0 during acceleration, driving with a sufficient current becomes possible at the same time as the start of the command, and galvano This has the effect of speeding up the start-up of the scanner and improving the acceleration characteristics at the start of driving, thus enabling faster driving. However, since the current waveform is disturbed, the magnitude of the initial value at the start of the command is set so that the current is not saturated.

In the example of FIG. 6, the triangular waves E and F are added together, but as in the fourth example shown in FIG. 7, the waveform G obtained by adding the waveform E and the waveform F from the beginning is
It is also possible to directly generate the command value waveform C ″ in addition to the command value C.

If the current applied at the same time as the start of the command can be made sufficiently high, for example, as shown in FIG. Alternatively, as shown in FIG. 9, it is possible to first give a maximum value and add the waveform I, J, or K that monotonically decreases as it is to the command value waveform C.

Although the present invention has been applied to the laser drill machine in the above-described embodiments, the object of application of the present invention is not limited to this, and if a galvano scanner is used, for example, a marking machine. It is obvious that other machines can be similarly applied.

[0035]

According to the present invention, the feedback control that requires high-speed processing is performed by the analog circuit, and the command value that does not matter at a relatively low speed is generated by the digital calculator. It can be realized at high speed.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration example of a galvano scanner control device according to the present invention.

FIG. 3 is a diagram showing an example of a relationship between a target angle of a mirror, a mirror angle, and a drive current in a conventional control method.

FIG. 4 is a target angle of the mirror in the first example of the present invention,
Diagram showing an example of the relationship between command value, mirror angle, and drive current

FIG. 5 is a diagram showing an example of a relationship among a target angle of a mirror, a command value, a mirror angle, and a drive current in the second example.

FIG. 6 is a diagram showing an example of a relationship among a target angle of a mirror, a command value, a mirror angle, and a drive current in the third example.

FIG. 7 is a diagram showing an example of a relationship among a target angle of a mirror, a command value, a mirror angle and a drive current in the fourth example.

FIG. 8 is a diagram showing an example of a waveform added to a command value in another modification of the present invention.

FIG. 9 is a diagram showing an example of a waveform added to a command value in the still another example of the present invention.

[Explanation of symbols]

10 ... Object to be processed 12 ... Laser beam 14, 16 ... Galvano scanner 15, 17, 20 ... Mirror 22 ... Motor 24 ... Angle sensor 30 ... Digital calculator 32 ... D / A converter 34 ... Analog circuit 36 ... Power amplifier

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 26/10

Claims (7)

(57) [Claims] 1. A method of controlling a galvano scanner for moving an irradiation position of a laser beam, wherein an acceleration / deceleration pattern of constant acceleration is applied by a digital computer.
A method for controlling a galvano scanner, characterized in that a command value having a waveform in which a triangular wave is superposed on a command signal is generated and feedback control for the command value is performed by an analog circuit. 2. For moving the irradiation position of a laser beam
In the control method of the galvano scanner, It is commonly used to generate a command value waveform with a digital calculator.
In addition, set the initial value that determines the magnitude of the current for starting
Occurs with the beginning, Feedback control for the command value to an analog circuit
Galvano scanner control method characterized by
Law. 3. A control device of a galvano scanner for moving an irradiation position of a laser beam, wherein a triangular wave is superimposed on an acceleration / deceleration pattern of constant acceleration.
A control device for a galvano scanner, comprising: a digital calculator for generating a command value of a waveform; and an analog circuit for performing feedback control on the command value. 4. The control device for a galvano scanner according to claim 3 , wherein the triangular wave has a waveform that once increases and then decreases. 5. The control device for a galvano scanner according to claim 3 , wherein the triangular wave has a waveform that monotonically decreases from an initial value. 6. For moving the irradiation position of a laser beam
In the control device of the galvano scanner, Generates the waveform of the command value, and at the same time
The initial value that determines the
A digital calculator, Analog that performs feedback control for the command value
Circuit, Control device for galvano scanner characterized by having
Place 7. The control device for a galvano scanner according to claim 6 , wherein the digital calculator generates a command value of a waveform for accelerating and decelerating at a constant acceleration.