JPH0623577A - Detector for converged position of converging optical system in laser beam machine - Google Patents

Abstract

PURPOSE:To automatically measure a converged position by detecting the output of a photodetector composing a positional sensor and discriminating the converged position to calculate the deviation of a converged position on an X-Y table. CONSTITUTION:Positional sensors are set to tables 2, 5, the tables 2, 5 are moved to a prescribed position and the positional sensors are irradiated with laser beam so that the coordinate axes in the X, Y direction of X-Y tables 2, 5 on a base 1 coincides with the coordinate axes in the X, Y directions of the positional sensor. The output of each photodetector composing the positional sensor is detected to discriminate which photodetector is irradiated with laser beam. The converged position of the laser beam is calculated by asking for the coordinate position of the positional sensor of the photodetector receiving the laser beam from the origin. In this way, the converged position can be detected in a short time and at a high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensing position detecting device for a condensing optical system in a laser processing machine for processing a workpiece by placing it on an XY table.

[0002]

2. Description of the Related Art In a printed circuit board, wiring is becoming finer and multilayered, and the thickness of copper foil used in the printed circuit board is becoming thinner. Therefore, to process the blind hole for connecting the inner layer and the outer layer, after removing the copper foil of the outer layer with a drill in advance to form a window hole, irradiate laser light through this window hole, the insulating substrate of the printed circuit board The use of a carbon dioxide laser has been proposed for the purpose of selectively removing carbon dioxide. When a carbon dioxide gas laser irradiates a laser beam on the copper material, the copper material can hardly be processed, leaving only an irradiation mark on the copper foil. Therefore, the insulating base material of the printed circuit board is selectively processed. Suitable for forming blind holes.

The diameter of the hole to be machined is also made smaller as the wiring of the printed circuit board is made finer, and in the case of the blind hole, the diameter is 0.2 mm or less. In order to accurately machine such a small-diameter hole, the irradiation position of the laser light must be accurately positioned in the window hole machined with the drill.

[0004]

Therefore, after irradiating a laser beam to a printed circuit board having a window hole formed by a drill, the deviation amount between the center of the irradiation mark and the center of the window hole is measured with a microscope. Based on the result, the correction amount is registered in the control device of the laser processing machine, and the laser processing machine performs the processing while correcting the irradiation position. In setting the correction amount, laser light irradiation and measurement are repeated many times to obtain an appropriate value. However, not only is it time-consuming and poor in workability, but also the accuracy is insufficient.

In view of the above situation, an object of the present invention is to provide a condensing position detecting device of a condensing optical system in a laser processing machine which enables highly accurate measurement in a short time.

[0006]

In order to achieve the above object, according to the present invention, a plurality of light receiving elements are arranged in a matrix, and a position sensor is detachably arranged at a predetermined position on an XY table. When the laser light is irradiated toward the position sensor, the output of each light-receiving element that constitutes the position sensor is detected, and a discriminating device that discriminates the condensing position of the laser light, and based on the discrimination result, An arithmetic unit for calculating the shift amount of the light-condensing position with respect to the coordinate axes of the XY table is provided.

[0007]

The position sensor is attached to the XY table so that the XY coordinate axis of the XY table and the XY coordinate axis of the position sensor coincide with each other, and the XY table is placed at a predetermined position (eg, The origin position of the XY table is moved to a position where it should be opposed to the condensing optical system), and the position sensor is condensed and irradiated with laser light. Then, the output of each light receiving element forming the position sensor is detected to determine which light receiving element receives the laser beam. The focus position of the laser light is obtained by finding the coordinate position from the origin of the position sensor of the light receiving element receiving the laser light.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
It will be described based on. In the figure, 1 is the base of the laser processing apparatus. An X table 2 is supported on the base 1 so as to be movable in the X direction. A motor 3 is supported by the base 1 and moves the X table 2 via the screw feed mechanism 4. A Y table 5 is supported by the X table 2 so as to be movable in the Y direction. A motor 6 is supported by the X table 2 and moves the Y table 5 via the screw feed mechanism 7. 8 is a light collecting plate made of bricks,
It is attached to the base 1 via a bracket 9.

A laser oscillator 10 is supported by a column (not shown) of the laser processing apparatus. A laser beam 11 is emitted from the laser oscillator 11. An optical conduit 12 has one end connected to the laser oscillator 10 and the other end supported by a structural member 13 of the laser processing apparatus. Reference numeral 14 denotes a reflecting mirror, which is arranged in the light pipe 12. A condensing optical system 15 is supported by the column so as to be movable in the Z direction. Reference numeral 16 denotes an objective lens, which is arranged in the condensing optical system 15. A motor 17 is supported by the column and moves the condensing optical system 15 via a screw feed mechanism 18.

Reference numeral 20 denotes a beam splitter, which is a focusing optical system 1.
5 is detachably arranged. 21 is a position sensor in which a plurality of light receiving elements are arranged in a matrix. This position sensor 2
1, the light receiving element in the center is the X table 2 and the Y
It is removably arranged on the Y table 5 so that it coincides with the origin position of the table 5 and the coordinate axis of the position sensor coincides with the coordinate axes of the X table 2 and the Y table 5. Reference numeral 22 denotes a focus position determination device, which is connected to the position sensor 21. Two
Reference numeral 3 denotes a control device, which calculates a shift amount of the focus position based on the determination result applied from the focus position determination device 22 and a movement amount of the X table 2 and the Y table 5 based on the calculation result. A control unit for correction is provided. With the above configuration, after attaching the beam splitter 20 to the condensing optical system 15 and attaching the position sensor 21 to the Y table 5,
Based on a command from the control device 23, the X table 2 and the Y table 5 are moved, and the origin position thereof is moved to the focusing position of the focusing optical system 15 designed in the laser processing apparatus. In this state, the laser oscillator 10 is operated to oscillate the laser light 11. Then, the laser beam 11 passes through the inside of the optical conduit 12, is reflected by the reflecting mirror 13, enters the condensing optical system 15, is focused by the objective lens 16, and is irradiated onto the position sensor 21. At this time, a part of the laser light 11 is reflected by the beam splitter 20 and is irradiated and absorbed by the light collecting plate 8.

The focus position discriminating device 22 includes a position sensor 21.
The output of the light receiving element that constitutes the above is scanned and confirmed according to the arrangement order of the light receiving elements, and the position of the light receiving element receiving the laser beam 11 is determined. Then, this position is set to the control device 23.
Is applied to the calculation unit of. The arithmetic unit of the control device 23 obtains a difference from the origin position of the position sensor 21 from the position of the applied light receiving element, and registers the difference as a correction amount in the control unit.

In the discrimination device 22, for example,
As shown in FIG. 2, when the number of the light receiving elements 21mn receiving the spot 11a of the laser beam 11 is one, the position is applied to the arithmetic unit of the control device 23, and as shown in FIG. When there are two light receiving elements 21 mm and 21 mn receiving the 11 spots 11 a, the respective positions are applied to the arithmetic unit of the control device 23.

When two or more light receiving elements 21 mm and 21 mn are applied, the arithmetic unit of the control unit 23:
The values are divided into positions in the X direction and the Y direction, and the average value of a plurality of positions is calculated as the correction amount.

[0014]

As described above, according to the present invention, a plurality of light receiving elements are arranged in a matrix, and the position sensor is detachably arranged at a predetermined position on the XY table.
When a laser beam is emitted toward this position sensor, the output of each light receiving element that constitutes the position sensor is detected, and a discriminating device for discriminating the converging position of the laser beam, and the X- Since the calculation device for calculating the shift amount of the light collecting position with respect to the coordinate axis of the Y table is provided, the light collecting position of the light collecting optical system can be automatically measured, and the workability can be improved. Further, it is possible to improve the measurement accuracy and perform more accurate alignment in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a condensing position detecting device of a condensing optical system according to the present invention.

FIG. 2 is an enlarged view showing a detection state with a single light receiving element.

FIG. 3 is an enlarged view showing a detection state of a plurality of light receiving elements.

[Explanation of symbols]

 2 X table 5 Y table 11 Laser light 15 Condensing optical system 21 Position sensor 21ij Light receiving element 22 Discriminating device 23 Control device

Claims (1)

[Claims] 1. An XY table on which a workpiece is placed, and a Z table.
A condensing position detecting device of a condensing optical system in a laser processing machine having a condensing optical system movable in any direction, wherein a plurality of light receiving elements are arranged in a matrix form, and a predetermined position of the XY table. A position sensor that is detachably arranged in the
When a laser beam is emitted toward this position sensor, the output of each light receiving element that constitutes the position sensor is detected, and a discriminating device for discriminating the converging position of the laser beam, and the X- A condensing position detecting device of a condensing optical system in a laser processing machine, which is provided with an arithmetic device for calculating a deviation amount of a condensing position with respect to a coordinate axis of the Y table.