JPH04187393A - Laser beam machine - Google Patents

Abstract

PURPOSE:To enable stable and high-quality laser beam machining by changing the relative distance between an optical system and a product to be machined according to the cross section shape of the preset product to be machined and controlling the relative distance so that it is kept constant. CONSTITUTION:When the shape of a sample 6 is known in a Z stage 5 and its shape data is input into the control system 9, the height is controlled by the control system 9 based on its shape data. The optical system 3 can be followed by the control of the height of the control system 9 to this Z stage 5 along the surface shape of the sample 6 in the accuracy range of the shape data. When coarse adjusting follow-up function by the Z stage 5 is combined with fine adjusting follow-up function by an automatic focusing mechanism, since a distance between a condense lens and the data 6 can be kept constant stable and high-quality laser beam machining can be performed though the data 6 is not flat or uneven in height.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a laser processing apparatus, and more particularly to laser processing for processing a sample with a curvature using a laser beam.

BACKGROUND OF THE INVENTION In recent years, laser processing has been applied to various materials, greatly contributing to improved productivity.

As shown in FIG. 4, this type of laser processing apparatus includes a laser light source 1, an optical system 3, a stage 7 on which a sample 6 is placed, and a stage 7 that is arranged in the X-axis direction and the Y-axis direction. XY to move to
It consists of a stage 8 and a control system 9 that controls the laser light source 1 and the XY stage 8.

As the laser light source 1, CO2 laser, YAG laser, A
An r laser, an excimer laser, etc. are used, and are selected depending on the material of the sample 6 and the purpose of processing.

The optical system 3 has the function of shaping the laser beam emitted from the laser light source 1 according to the processing purpose and focusing it on the sample 6. - For boat fishing, as shown in FIG. , a beam expander 32, and a condenser lens 33.

Here, the beam expander 32 is for expanding the beam diameter of the laser beam and collimating it.

The condensing lens 33 is for narrowing down the laser beam collimated by the beam expander 32.

Now, when the focal length of the condensing lens 33 is f and the diameter of the incident beam is D, the beam diameter at the focal point (commonly called spot diameter) do is given by do haze 4λf/πD.

Here, λ is the wavelength of the laser beam.

Therefore, the spot diameter d increases as the diameter of the beam incident on the condenser lens 33 increases. The spot diameter d can be made smaller. In order to make it smaller, the magnification of the beam expander 32 can be changed.

In addition, if it is necessary to observe the surface of sample 6,
As shown in the figure, a lighting device 34, a television camera 35, and a television monitor 36 may be added to the above configuration.

The sample 6 is installed and fixed on a stage 7, and the stage 7 is installed and fixed on an XY stage 8.

A control system 9 controls the laser light source ↓ and the XY stage 8.

In the case of the above-mentioned configuration, the sample 6 is normally flat and the focus position of the laser beam is first fixed on the surface of the sample 6, and the laser beam is moved while the sample 6 is moved by the XY stage 8. A method of irradiation is used.

However, in this case, the height of the sample 6 changes depending on the flatness of the XY stage 8, so the machined surface of the sample 6 deviates from the focal position, changing the processing width and depth, resulting in a decrease in processing quality. there's a possibility that.

Furthermore, when the sample 6 is not flat but has a curved surface, an automatic focusing mechanism is incorporated so that the distance between the sample 6 and the condensing lens 33 is kept constant.

As a general configuration example of this type, as shown in FIG.
, a motor 38 that drives the vertical drive mechanism 37, and a sample 6.
Some devices include an automatic focus signal detection head (hereinafter referred to as Ale' head) 39 that detects the distance between the Ale' and the condensing lens 33, and an automatic focus control circuit (hereinafter referred to as AF controller) 40.

A typical example of this vertical drive mechanism 37 is to attach a gear to the lens mount of the condensing lens 33, and mesh this gear with another gear driven by the motor 38.
There are methods such as driving by

The AF head 39 is composed of a light source such as a laser diode, a photosensor that detects reflected light from the sample 6, and an optical system such as a lens or mirror for irradiating the sample 6 with light from the laser diode. An electrical signal is output depending on the distance between the condenser lens 33 and the sample 6.

The AF controller 40 converts the output signal from the AF head 39, amplifies it, and outputs it to the motor 38.

In other words, when the distance between the condensing lens 33 and the sample 6 increases,
Motor 3 according to the output signal from AF controller 40
8 rotates and is controlled so that the distance between the condenser lens 33 and the sample 6 is always a constant distance.

In this way, even if the sample 6 has a curved surface or if the sample 6 is flat and the XY stage 8 has poor flatness, the distance between the condenser lens 33 and the sample 6 can be maintained at a constant distance. , it is possible to realize stable laser processing.

In such a conventional laser processing apparatus, by incorporating an automatic focusing mechanism, it is theoretically possible to perform laser processing even on a sample having a curved surface.

In recent years, various automatic focusing methods have been developed, including optical methods, capacitance detection methods, and air gap methods, depending on the distance detection method.

However, these methods have problems in that the material of the sample 6 is limited and the sensitivity varies depending on the degree of curvature of the sample 6.

For example, in the case of an optical method, a predetermined light is projected onto the sample 6 and the reflected light from the sample 6 is detected. This method becomes difficult to use if the objects are scattered.

In addition, in the case of the capacitance detection method, it cannot be used unless the sample 6 is conductive, and in the case of the air gap method, an air nozzle is attached to the tip of the condensing lens 33, so the condensing lens 33 There is a problem that the working distance is substantially shortened, making it difficult to use for a sample 6 with a large slope.

Furthermore, in order to increase sensitivity and improve response in a normal autofocus mechanism, it is necessary to move the lightest part up and down as much as possible, so as shown in Figure 7, the condenser lens 3
A method is adopted in which only 3 is driven up and down.

Therefore, the stroke of the vertical drive cannot be very large, and is usually on the order of a few I. Therefore, it is difficult to apply the above laser processing method to the sample 6, which has a curved surface with a height difference of several tens of I. There's a problem.

Purpose of the Invention The present invention has been made in order to eliminate the problems of the conventional products as described above. The object of the present invention is to provide a laser processing device that can maintain constant constant value and realize stable, high-quality laser processing.

Structure of the Invention A laser processing apparatus according to the present invention moves a condensing lens of an optical system in a direction perpendicular to a processing surface of a workpiece, and adjusts the distance between the condenser lens and the workpiece to a predetermined distance. A laser processing apparatus for processing the workpiece with a laser beam focused by the condenser lens while maintaining a relative position between the optical system and the workpiece in a direction perpendicular to the processing surface. A moving means for changing the distance, and a control means for changing the relative distance according to a cross-sectional shape of the workpiece set in advance by the moving means and controlling the relative distance to be maintained at a constant distance. It is characterized by

Example Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, a laser processing apparatus according to an embodiment of the present invention includes a laser light source 1 that emits a laser beam, an optical fiber 2 that guides the laser beam emitted from the laser light source 1 to an optical system 3, and a laser light source 1. an optical system 3 for shaping the laser beam from the laser beam into a desired shape and focusing it on the surface of the sample 6; and an automatic focusing mechanism 4 for keeping the distance between the condensing lens (not shown) and the sample 6 at a constant distance. , a Z stage 5 for vertically moving the optical system 3 with respect to the sample 6, a stage 7 for mounting the sample 6, an XY stage 8 for horizontally moving the sample 6, and a laser light source 1. and a control system 9 that controls the automatic focusing mechanism 4, the two stages 5, and the XY stage 8, respectively.

One embodiment of the present invention is characterized in that the optical system 3 is equipped with an automatic focusing mechanism 4, and the optical system 3 is moved vertically by a Z stage 5, and the surface of the sample 6 is not flat but curved. It has the following.

The operation of one embodiment of the present invention will be described below with reference to FIG.

First, the automatic focusing mechanism 4 may be of a conventional method, that is, an optical method, a capacitance detection method, or an air gap method. Therefore, the stroke of this automatic focusing mechanism 4 is approximately several inches.

On the other hand, the stroke of the Z stage 5 may have a little more margin depending on the height difference of the curved surface of the sample 6. For example, if the height difference of sample 6 is about 501 Im,
The stroke of the Z stage 5 may be about 601.

When the shape of the sample 6 is known, the height of the Z stage 5 is controlled by inputting the shape data to the control system 9 based on the shape data.

Due to the height control of the control system 9 for these two stages 5,
The optical system 3 can be made to follow the surface shape of the sample 6 within the precision range of the shape data.

In this case, since the automatic focusing mechanism 4 performs final tracking of the sample 6 with high precision, the tracking precision of the Z stage 5 is not required so much.

For example, the tracking range of the optical autofocus mechanism 4 is ±50
#I, the Z stage 5 only needs to have a tracking accuracy of ±50 sl.

When controlling the height of the Z stage 5 by the control system 9, the problem is whether or not it is possible to actually obtain the shape data of the sample 6 in the height direction. If there is, there will be no problem since the error between the design data and the actually manufactured shape will be only a few centimeters.

In addition, if the sample 6 is deformed due to the way it is placed on the stage 7, place the -degree sample 6 on the stage 7 and then use the automatic focusing mechanism 4 to track the sample 6 without emitting the laser beam. and move the optical system 3 by the Z stage 5,
What is necessary is to obtain height data of necessary points on the sample 6.

As mentioned above, by combining the coarse movement tracking function of the two stages 5 and the fine movement tracking function of the automatic focusing mechanism 4, even if the sample 6 is not flat or has a difference in height, the converging lens and the sample 6 can be easily aligned. Since it is possible to maintain the distance constant, stable and high-quality laser processing can be achieved, and the range of application of laser processing can be expanded.

FIG. 2 is a block diagram showing another embodiment of the present invention. In the figure, another embodiment of the present invention has an optical system 3 fixed,
Except that the sample 6 is moved by two stages 10 and an XY stage 11, the structure is the same as that of the embodiment of the present invention shown in FIG. 1, and the same components are denoted by the same symbols. be. Further, the operations of these same components are similar to those in one embodiment of the present invention.

In other embodiments of the present invention, the optical system 3 is fixed, so the optical fiber 2 is not required.

Furthermore, since the height of the Z stage 10 and the XY stage 11 is controlled by the control system 9 based on the shape data of the sample 6, the sample 6 is moved up and down according to the shape data, and within the precision range of the shape data. Optical system 3 and sample 6
The distance between them is kept constant.

Therefore, another embodiment of the present invention is applied when the sample 6 is relatively small and light.

FIG. 3 is a block diagram showing another embodiment of the present invention. In the figure, another embodiment of the present invention is similar to the embodiment of the present invention shown in FIG. 1, except that the sample 6 is fixed and the optical system 3 is moved by a Z stage 12 and an XY stage 13. The structure is as follows, and the same components are given the same reference numerals. Furthermore, the operations of these same components are similar to those in one embodiment of the present invention.

In another embodiment of the present invention, the optical system 3 is moved by the Z stage 12 and the XY stage 13, so that the laser beam emitted from the laser light source 1 is guided to the optical system 3 by the optical fiber 2.

In addition, since the height of the second stage 12 and the XY stage 13 is controlled by the control system 9 based on the shape data of the sample 6, the optical system 3 is moved vertically and horizontally according to the shape data, and the shape data is The distance between the optical system 3 and the sample 6 is kept constant within the accuracy range of .

On the other hand, since the sample 6 is placed on the stage 7 and is fixed, another embodiment of the present invention can be used when the sample 6 is large and heavy, or when the sample 6 has a complicated shape. Applicable.

In this way, by performing laser processing by combining the coarse movement tracking function of the Z stage 5.10.12 and the fine movement tracking function of the automatic focusing mechanism 4, it is possible to perform laser processing when the sample 6 is not flat or has height differences. Even in this case, the distance between the condenser lens and the sample 6 can be kept constant.

Therefore, the processing width, processing method, etc. can be kept constant, and stable, high-quality laser processing can be realized.

Further, laser processing can also be applied to the sample 6 whose shape has conventionally been impossible to process.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the relative distance between the optical system and the workpiece is changed according to the preset cross-sectional shape of the workpiece, and the relative distance is maintained at a constant distance. Through control, the distance between the workpiece and the condensing lens can be kept constant even when the workpiece surface is not flat or has a large height difference, achieving stable, high-quality laser processing. It has the effect of being able to.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a block diagram showing another embodiment of the present invention, Fig. 3 is a block diagram showing another embodiment of the present invention, and Fig. 4 is a block diagram showing another embodiment of the present invention. is a configuration diagram showing a conventional example;
Figure 6 is a configuration diagram showing a conventional processing optical system, Figure 6 is a configuration diagram showing an optical system using a conventional monitor, and Figure 7 is a configuration diagram showing a case using a conventional automatic focusing mechanism. be. Explanation of symbols of main parts 1... Laser light source 2... Optical fiber 3... Optical system 4... Automatic focusing mechanism 5.10.12... ...Z stage 6...
Sample 8.11.13...XY stage 9...
・Control system

Claims (1)

[Claims] (1) Move the condenser lens of the optical system in a direction perpendicular to the processing surface of the workpiece, and keep the distance between the condenser lens and the workpiece at a predetermined distance while concentrating the condenser lens. A laser processing device that processes the workpiece using emitted laser light, a moving unit that changes a relative distance between the optical system and the workpiece in a direction perpendicular to the processing surface; A laser processing apparatus comprising: a control means for changing the relative distance according to a cross-sectional shape of the workpiece set in advance by the moving means, and controlling the relative distance to be maintained at a constant distance.