JP3383876B2 - Laser processing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for processing a work by irradiating the work with a laser beam emitted from a laser oscillator such as an excimer laser. The present invention relates to a laser processing apparatus for processing an object to be processed which has a composition of materials.

[0002]

2. Description of the Related Art A laser processing apparatus is an apparatus for processing a work by irradiating the work with a laser beam emitted from a laser oscillator. The laser processing apparatus is used to process a workpiece, particularly a coating material portion, which is a combination of a base material and a coating material as two or more different materials. For example, when processing a plastic material on which a metal thin film such as copper foil is formed, or a metal wire whose surface is covered with plastic such as polyimide, paper, glass fiber, etc., do not damage the underlying material. , It is often required to process only the surface coating material.

A phenomenon called "ablation" occurs on the surface portion of the work piece irradiated with the laser beam.
Ablation is a phenomenon in which the coating material of the work piece is instantaneously removed, and the mechanism has not been clarified in detail (Laser Society Research Group report, RTM-91-33.
~ 41, October 29, 1991), the workpiece absorbs the energy of the irradiated laser light and the bond is broken, and a spherical plasma-like object called a plume is generated and scatters into pieces. It is thought to go. Therefore, every time the laser light is applied in a pulsed manner, the coating material is gradually scraped from the surface in the depth direction (direction of the base material).

As for the processing work of only the coating material by the laser processing apparatus for such a workpiece made of two or more different materials, a method of performing laser irradiation with small energy (in a short time) many times is adopted. . In this method, a preliminary test is performed in advance to determine the number of times of laser irradiation, and then the actual processing is performed.

However, in the conventional processing method as described above, there is a problem that a preliminary test has to be performed, and substantially the same process has to be performed twice.

Further, considering the output stability (variation between irradiations or deterioration with time) of a laser oscillator, especially an excimer laser oscillator, the number of irradiations must be increased as compared with the result of the preliminary test, and the base material is damaged. There is a problem that there are many things.

Further, it is possible to inspect each time irradiation is performed a predetermined number of times so that the irradiation is completed before the underlying material is damaged, but there is a problem that the processing time becomes long.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in particular, in processing a workpiece composed of a base material and a coating material made of two or more different materials, An object of the present invention is to provide a laser processing apparatus capable of processing a surface coating material without damaging a base material and efficiently performing the processing.

Another object of the present invention is to provide a laser processing apparatus capable of omitting a troublesome step of determining the number of laser irradiations by conducting a preliminary test in advance.

It is another object of the present invention to provide a laser processing apparatus which does not need to be inspected for damage to the underlying material.

[0011]

Means for Solving the Problems That is, according to the present invention, air vibration (sound wave) from a workpiece during laser beam machining
Alternatively, it is focused on the fact that the material of the workpiece can be determined by detecting the change of the vibration wave such as the mechanical vibration or the change due to the strain. The first invention is emitted from the laser oscillator. A laser processing apparatus for processing a workpiece by irradiating the workpiece with a laser beam, wherein a light amount detecting means for detecting a light amount of the laser beam, and a vibration wave during processing from the workpiece A laser processing apparatus comprising: a vibration wave detecting means for detecting; and a control means for controlling the laser oscillator based on output signals from the vibration wave detecting means and the light amount detecting means.

Instead of the vibration wave detecting means, it is possible to provide a frequency component detecting means capable of detecting a frequency component obtained by frequency-converting the height of the vibration wave during processing.

In addition to the vibration wave detecting means, a frequency component detecting means capable of detecting a frequency component obtained by frequency-converting the height of the vibration wave during processing can be provided.

The object to be processed can be composed of at least a base material and a coating material formed on the surface of the base material.

The control means can detect the material of the workpiece based on the output signals from the light amount detection means and the vibration wave detection means.

The output signal from the vibration wave detecting means can be subjected to correction processing according to the level when the output signal from the light amount detection signal is zero.

The output signal from the vibration wave detecting means can be corrected according to the output signal from the light quantity detecting means.

The vibration wave detecting means can be used as a sound volume detecting means.

The vibration wave detecting means may be mechanical vibration wave detecting means.

A second invention is a laser processing apparatus for processing a work by irradiating the work with a laser light emitted from a laser oscillator, and detecting the light quantity of the laser light. Means, a strain detecting means for detecting the strain at the time of processing from the work piece, and a control means for controlling the laser oscillator based on the output signals from the strain detecting means and the light amount detecting means are provided. It is a laser processing apparatus characterized by the above.

[0021]

In the laser processing apparatus according to the present invention, a vibration wave such as a sound wave or a mechanical vibration wave from the work piece, or a distortion of the work piece is detected during processing by the laser beam. Further, since these detection signals differ depending on the amount of light from the laser oscillator, it is possible to detect the material of the workpiece based on the detection signal of the vibration wave or strain and the detection signal of the amount of light.

Based on this detection, the control means judges that the portion to be processed by the laser light has reached the base material from the coating material, and stops the laser oscillator, thereby finishing the processing of the workpiece. . Moreover, since the laser light can be oscillated on the order of several hundreds of pulses per second, there is sufficient time margin for the judgment by the control means, and the laser oscillation can be performed before the deep processing is performed on the base material. It can be stopped and does not damage the underlying material.

Therefore, it is not necessary to carry out a preliminary working process or to check the working depth for each working as in the conventional case, and the laser working can be carried out efficiently and surely.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a laser processing apparatus 1 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view of a laser processing apparatus 1, which is a laser processing apparatus 1.
Is an excimer laser oscillator 2, a partial reflecting mirror 3, a light amount detector 4, and a volume detector 5 as a vibration wave detecting means.
And a calculation means 6.

The workpiece 7 to be processed by the laser processing apparatus 1 has a surface of a base material 8 covered with a coating material 9.

The laser light emitted from the excimer laser oscillator 2 is partially reflected by the partial reflecting mirror 3 and enters the light amount detector 4. The light quantity detector 4 detects the light quantity of the incident light and outputs an output signal according to the light quantity.

On the other hand, the laser light transmitted through the light quantity detector 4 is applied to the workpiece 7 via an optical system (not shown) such as a lens and a mirror.

In the laser processing apparatus 1 having such a structure, the processing speed by the above-mentioned ablation varies depending on the material of the workpiece 7. That is, it is necessary to change the irradiation time and the irradiation frequency of the laser light depending on the material of the workpiece 7. For example, when comparing the processing speeds of a metal material and a plastic material, the plastic material is about 1 to 2 digits faster than the metal material.

Therefore, when the base material 8 is a metal material and the coating material 9 is a plastic material, the base material 8 is not damaged by increasing the irradiation energy once or by increasing the irradiation frequency. The coating material 9 can be completely removed. On the contrary, the base material 8
Is a plastic material and the coating material 9 is a metal material,
Since the plastic material will be rapidly damaged when the metal material is removed, at least when the removal of the metal material is approaching, it is necessary to reduce the irradiation energy for one time so as not to damage the plastic material. There is.

However, in the ablation process, since the ablation does not occur unless the irradiation energy per unit area exceeds the threshold value, it is necessary to be careful in adjusting the laser light amount.

As described above, the laser beam applied to the workpiece 7 will process the workpiece 7. Along with this processing, a part of the energy of the laser light becomes a sound peculiar to the processing and is input to the volume detector 5.

The sound at the time of processing differs depending on the material of the workpiece 7 and the amount of laser light applied. The calculation means 6 detects the material of the workpiece 7 based on the sound volume detection signal from the sound volume detector 5 and the light quantity detection signal from the light quantity detector 4, and the processed portion from the coating material 9 to the base material 8 is processed. The excimer laser oscillator 2 is stopped when it is determined that the excimer laser oscillator 2 has been moved to.

When it is necessary to obtain the frequency component of the sound at the time of processing, the frequency component detecting means 10 is provided in the calculating means 6 and the Fourier transform processing is performed to obtain the frequency. Also in the case of detecting the frequency component, as in the case of detecting the volume, the calculating means 6 determines the material of the workpiece 7 based on this frequency component and the output signal of the light quantity detector 4, and the excimer laser oscillator. Control 2

In an environment with a lot of background noise, in order to detect only the sound at the time of processing, the sound level when the output signal of the light quantity detector 4 is zero, that is, when the laser light is not irradiated, is set. It is effective to perform correction processing which is stored in the calculation means 6 and is subtracted from the sound level at the time of laser processing when the output signal of the light quantity detector 4 shows a certain value. With respect to the frequency component as well, it is possible to perform the same correction processing in the calculating means 6.

Further, it should be noted that the sound during processing changes depending on the amount of laser light from the excimer laser oscillator 2. That is, it is necessary to incorporate a correction table showing how the sound (volume and frequency of sound) changes according to the change of the light amount into the calculation means 6 to perform the correction process.

Although a commercially available microphone can be used as the volume detector 5 to obtain a sufficient output signal, the object to be processed 7 is placed in a soundproof room (not shown in the drawing) particularly when a target with high sensitivity is targeted. It is effective to use a microphone with high directivity in a soundproof room by letting the laser light enter through the opening window. Further, the same judgment as described above can be made by detecting the ultrasonic wave according to the type of the laser oscillator or the work piece.

As a laser oscillator for processing,
Other than the excimer laser, it can be applied as long as it emits sound during processing.

In the present invention, the discrimination between the coating material 9 and the base material 8 is made by detecting the sound which is air vibration, but the vibration of the workpiece 7 portion is directly detected. You may do it.

That is, FIG. 2 is a schematic view of a laser processing apparatus 11 according to a second embodiment of the present invention, in which the laser processing apparatus 1 of FIG.
In the configuration different from the above, the mechanical vibration wave detecting means 12 is directly attached to the workpiece 7 instead of the volume detector 5, and the mechanical vibration state can be detected.

In the laser processing apparatus 11 having such a structure, as in the laser processing apparatus 1 described above, the progress of processing is detected by detecting the difference in the mechanical vibration state between the coating material 9 and the base material 8. It is possible to grasp the situation and control the excimer laser oscillator 2.

In the present invention, instead of detecting the vibration wave by the volume detector 5 such as the microphone or the mechanical vibration wave detecting means 12, the discrimination is made by detecting the strain of the workpiece. Good.

That is, FIG. 3 is a schematic view of a laser processing apparatus 13 according to a third embodiment (second invention) of the present invention, in which the laser processing apparatus 1 and the laser processing apparatus 1 of FIG. 2 is different from the laser processing apparatus 11 shown in FIG.
4 are installed densely, and it is possible to detect the generation state of the distortion due to the processing by the laser light.

In the laser processing apparatus 13 having such a structure, similarly to the laser processing apparatuses 1 and 11 described above, a distortion generation state depending on whether the processing progressing portion is the coating material 9 portion or the base material 8 portion is reached. By detecting the difference, it is possible to grasp the progress of processing and control the excimer laser oscillator 2.

[0044]

As described above, according to the present invention, the amount of laser light from the laser oscillator is detected by detecting the sound volume or mechanical vibration wave at the time of processing from the material to be processed, their frequency components, and distortion. By comparing with, it is possible to detect a change in the material of the workpiece, and it is possible to efficiently remove only the coating material without damaging the underlying material.

[0045]

[Brief description of drawings]

FIG. 1 is a schematic diagram of a laser processing apparatus 1 according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a laser processing apparatus 11 according to a second embodiment of the present invention.

FIG. 3 is a schematic view of a laser processing apparatus 13 according to a third embodiment (second invention) of the present invention.

[Explanation of symbols]

1 laser processing equipment 2 Excimer laser oscillator (laser oscillator) 3 partial reflector 4 Light intensity detector (light intensity detector) 5 Volume detector (volume detection means) (vibration wave detection means) 6 Computing means (control means) 7 Workpiece 8 Base material 9 Coating material 10 Frequency component detecting means 11 Laser processing equipment 12 Mechanical vibration wave detection means (vibration wave detection means) 13 Laser processing equipment 14 Strain gauge (strain detection means)

Claims (7)

(57) [Claims] 1. A laser processing apparatus for processing a workpiece by irradiating the workpiece with a laser beam emitted from a laser oscillator, comprising: a light amount detecting means for detecting a light amount of the laser beam; Rutotomoni provided a vibration wave detecting means for detecting vibration waves during processing from the workpiece, and control means for controlling the laser oscillator based on the output signal from the vibration wave detecting means and said light amount detecting means, the , the output signal from said vibration wave detecting means, said light quantity detecting hands
Correcting this depending on the output signal from the stage
Laser processing apparatus characterized by the. 2. The frequency component detection means capable of detecting a frequency component obtained by frequency-converting the height of the vibration wave during processing is provided in place of the vibration wave detection means. The laser processing device described. 3. The frequency component detection means capable of detecting a frequency component obtained by frequency-converting the height of the vibration wave during processing is provided in addition to the vibration wave detection means. The laser processing device described. 4. The laser processing apparatus according to claim 1, wherein the work piece is composed of at least a base material and a coating material formed on the surface of the base material. 5. The control means detects the material of the workpiece based on output signals from the light quantity detection means and the vibration wave detection means.
The laser processing device described. 6. The laser processing apparatus according to claim 1, wherein the vibration wave detecting means is a volume detecting means. 7. The laser processing apparatus according to claim 1, wherein the vibration wave detecting means is a mechanical vibration wave detecting means.