JPH0489192A - Laser beam machine - Google Patents

Abstract

PURPOSE:To allow the easy and efficient focusing of laser beams to plural processing points and the simultaneous execution of desired processing at the plural processing points by respectively deflecting the light of the P polarization component of the laser beams and the light of the S polarization component of the beams and focusing the light to a work. CONSTITUTION:The laser beam emitted from a laser device 11 11 is divided to the plural light beams and these light beams are focused to the plural points of the work 14, by which the plural points of the work 14 are subjected to laser beam processing. The progressing direction of the light Lp2 of the P polarization component of the above-mentioned laser beam L0 and the progressing direction of the light Ls2 of the S polarization component are varied by polarizing prisms 16, 17. The light Lp2 of the P polarization component and the light Ls2 of the S polarization component are focused respectively to the work 14 by a condenser lens system 13. The polarizing prisms 16, 17 of the above-mentioned polarized light deflecting means are the prisms which can vary the angle formed by the progressing direction of the light Lp2 of the P polarization component and the progressing direction of the light Ls2 of the S polarization component. Further, The energy ratio of the light of the P polarization component and the S polarization component is preferably varied by interposing a quarter- wave plate 15 between the above-mentioned laser device 11 and the above-mentioned polarizing prisms 16,17 as a phase difference changing means which can change the difference between the phase of the light Lp2 of the P polarization component and the phase of the light Ls2 of the S polarization component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a laser processing device that simultaneously performs welding, drilling, and other laser processing on a plurality of locations on a workpiece.

[Prior Art] For example, the device shown in FIG. 2 is known as a laser processing device that focuses laser light on a plurality of processing points and simultaneously performs desired processing on the plurality of processing points. (See Publication No. 54-39334).

This device uses a laser beam LO emitted from a laser device 1.
The beam diameter is expanded by a beam expander 2 consisting of a concave lens 2a and a convex lens 2b, etc., and then a multi-lens 3 combining two lenses 3a and 3b is used to focus two points AI on the surface of workpiece #@4, It is designed to focus on A2.

[Problems to be Solved by the Invention] Depending on the processing application, the energies of multiple laser beams focused on the surface of the workpiece may be exactly the same, and the energy of the laser beams may be different from that of the workpiece. It may be necessary to apply perpendicular to the surface.

For example, consider a case where this type of laser processing apparatus is used for fixing metal foil to the surface of a thick plate by spot welding. Normally, in this case, it is necessary to spot weld a large number of places, so using this type of laser processing equipment, which can spot weld multiple places at the same time with -1 degree processing, allows for rapid processing and extremely It is valid. However, if there is a difference in the energy of the laser beam applied to multiple processing points that are processed at the same time, or if energy is applied from an oblique direction, the metal foil may be deformed due to an imbalance of thermal strain. This results in the inconvenience that the adhesive may float off the surface of the thick plate and the desired adhesion cannot be achieved.

Focusing on this point, the above-mentioned conventional laser processing equipment
It is extremely difficult to make the energy of the two focal points exactly the same, and energy can only be applied from a direction perpendicular to the surface of the workpiece.

That is, the laser beam LO emitted from the laser device]
is usually a Gaussian beam in which the light intensity distribution in the beam cross section is strong in the center and rapidly weakens toward the periphery, as shown in Figure 3(a). . This Gaussian beam enters the multi-lens 3 as shown in FIG. 3(b). In other words,
The part with the maximum light intensity is the two lenses 3 of the multi-lens 3
It is located on the boundary line 3C between a and 3b. Therefore, even if the position at which the laser beam LO is cut on this boundary line 3c changes slightly, the ratio of the energy of the laser beams focused on A1 and A2 will change greatly, making the energies of the two exactly the same. It is extremely difficult to do so.

Further, the energy of the light focused by the two lenses 3a and 3b of the multi-lens 3 is strong near the boundary line 3c (indicated by the dashed line in Fig. 2), and weak in the periphery (indicated by the dashed line in Fig. 2). ). As a result, energy is applied obliquely to the surface of the workpiece 4 at the processing points A1 and A2.

Furthermore, depending on the application, the focal point (AI, A2 >
There are cases where it is desired to freely set the interval between the focal points, but with the conventional laser processing equipment described above, the only way to change the interval between the focal points is to replace the multi-lens 3, and furthermore, it can only be set within the range of the prepared lenses. .

In addition, in the conventional laser processing apparatus described above,
), there is also a drawback that the entire laser beam LO cannot be made incident on the multi-lens 3, and the negative portion is wasted.

The present invention was made against the above-mentioned background, and it is an object of the present invention to efficiently focus a laser beam on a plurality of processing points without using multiple lenses, and to simultaneously perform desired processing on these plurality of processing points. The object of the present invention is to provide a laser processing apparatus that allows the energy ratio of a plurality of focusing points and the interval between the focusing points to be relatively freely set.

[Means for Solving the Problems] The present invention solves the above problems by having the following configuration.

(1) A laser that simultaneously performs laser processing on multiple locations on the workpiece by dividing the laser light emitted from the laser light generating means into multiple light beams and focusing them on multiple locations on the workpiece. In the processing device, a polarization deflecting means for making the traveling direction of the P-polarized light component of the laser light emitted from the laser light generating means different from the traveling direction of the S-polarized light component light, and the light of the P-polarized light component and S
A structure characterized by having a condensing means for converging each of the polarized light components onto a workpiece.

(2) The laser processing apparatus according to claim 1, wherein the polarization angle means is capable of varying the angle formed by the traveling direction of the P-polarized light component and the traveling direction of the S-polarized light component. The configuration was as follows.

(3) In the laser processing apparatus according to claim 1, there is provided a position between the laser beam generating means and the polarization angle means that can vary the phase difference between the phase of the P-polarized light component and the phase of the S-polarized light component. A configuration characterized in that the energy ratio of P-polarized light component and S-polarized light component is made variable by interposing a phase difference changing means.

[Operation] According to the above configuration (1), if the traveling direction of the P-polarized light component of the laser light emitted from the laser light generating means is different from the traveling direction of the s4 light component by the polarization angle means, It is closed. Therefore, when the P-polarized component light and the S-polarized component light are focused onto the workpiece by the focusing means, they are focused on different locations on the workpiece, and each location is processed simultaneously.

According to this configuration, the laser beam can be focused on a plurality of processing locations on the workpiece without using multiple lenses. In this case, it is possible to make all of the laser light incident on the condensing means, and it is possible to prevent a part of the laser light from being wasted as in the case of using multiple lenses, allowing efficient processing. becomes. Moreover, unlike when using multiple lenses, the intensity distribution of the light that is split into multiple parts does not become biased to one side, so it is possible to prevent light energy from entering the workpiece at an angle. It becomes possible.

Further, according to configuration (2), the polarization angle means allows P
If you change the angle between the traveling direction of the polarized component light and the traveling direction of the S-polarized component light, the distance between the convergence points of the light condensed onto the workpiece by the condensing means will change. It becomes possible to arbitrarily set the distance between locations within a predetermined range.

Furthermore, according to configuration (3), when the phase difference is changed by the phase difference changing means, the energy ratio of the P-polarized light component and the S-polarized light component, which are not separated by the polarization angle means, is changed. This makes it possible to adjust the energy of the light focused on the workpiece at the focus point to be exactly equal.

[Example] Fig. 1 is a diagram showing the configuration of a laser processing device according to an embodiment of the present invention, Fig. 4 is an explanatory diagram of the operation of a unit polarizing prism,
Fig. 5 is an explanatory diagram of the action of the first polarizing prism group, Figs. 6 and 7 are explanatory diagrams of the action of the first and second polarizing prism groups, and Fig. 8 is an illustration of how the focal point interval is changed. FIG. Hereinafter, one embodiment will be described in detail with reference to these drawings.

In FIG. 1, the reference numeral 11 is a laser device as a laser beam generating means, the reference numeral 13 is a condensing lens system constituting a condensing means,
Reference numeral 14 is a workpiece, reference numeral 15 is a 174-wavelength plate constituting a phase difference changing means, and reference numbers 16 and 17 are first and second polarizing prism groups, respectively, constituting a polarization deflection means.

The laser device 1 emits a laser beam LO for processing, and in this embodiment, a YAG laser device that generates a relatively high output pulsed laser beam is used. In this case, this laser light LO is linearly polarized light.

Sharing the optical axis with the laser beam LD emitted from the laser device 11, the 174-wave plate 15, the first polarizing prism group 16, the second polarizing prism group 17, and the concentrator are sequentially arranged toward the right in the figure. An optical lens system 13 is arranged. The workpiece 14 is placed to the right of the condenser lens system 13 in the figure.

The 174-wavelength plate 15 is normally arranged so that its crystal axis is at an angle of 45° to the electric field vector of the linearly polarized laser beam LO, and converts the laser beam LO into circularly polarized light. That is,
In this case, when the laser beam LO is divided into a P-polarized light component and an S-polarized light component by the polarizing prism groups 16 and 17, the energy ratios of the P-polarized light component and the S-polarized light component become equal in principle. Note that when the angle that the crystal axis of this 174-wave plate 15 makes with respect to the laser beam LO is changed from 45 degrees, the laser beam LO becomes elliptically polarized light, and the energy ratio of the P-polarized light component and the S-polarized light component after splitting becomes This allows the energy ratio between the two to be adjusted.

Therefore, in practice, P after branching
The energy ratio of the polarized light component and the S-polarized light component can be set to be exactly equal.

The first and second polarizing prism groups 16 and 17 include unit polarizing prisms 16a and 16b, and 17a and 17.
b, and each of these constitutes a so-called Wollaston polarizing prism.

Next, the specific structure and operation of the first and second polarizing prism groups 16 and 17 will be explained with reference to FIGS. 4 to 7.

FIG. 4 is a sectional view of a unit polarizing prism 16a constituting the first polarizing prism group 16. This unit polarizing prism 16a is made of calcite or other birefringent crystalline optical material, has an apex angle of γ, and has a crystal axis perpendicular to the optical axis O in the plane of the paper, as shown by arrow A in the figure. It is formed to be. Now, let the ordinary ray refractive index of this unit polarizing prism 16a in the direction of arrow A be no, the extraordinary ray refractive index in the direction perpendicular to the plane of the paper and the optical axis 0 be ne, and from the optical axis O direction, a P polarized light component and an Sm light component. Let us consider the case where a laser LO including . Then, the traveling directions of the P-polarized light component and the S-polarized light component of the laser beam LO are changed so that they form different angles with respect to the optical axis in the plane of the drawing.

The angles (arcination angles) of the P-polarized light component light Lpl and the S-polarized light component light Lsl emitted from this unit polarizing prism 16a with the optical axis O are δp1. If δS1, δp1
．． δS1 is approximately expressed by the following equation.

P-polarized light polarization angle; δp1-γ(ne-1)... ■S-polarized light polarization angle: δ51=7 (no-1) -■ FIG. 5 is a cross-sectional view of the first polarizing prism group 16. As shown in FIG. 5, this first polarizing prism group 16 includes a unit polarizing prism 16b having a crystal optical axis 0 in a direction perpendicular to the plane of the paper and the optical axis O, and having an apex angle of γ. polarizing prism 1
The inclined surface of the unit polarizing prism 6b is in contact with the inclined surface of the unit polarizing prism 16a, and the apex angle directions are opposite to each other. Therefore, the polarizing light LO incident on the first polarizing prism group 16 is first changed in its traveling direction by the angle expressed by the above equations (1) and (2) by the unit polarizing prism 16a, and then the unit polarizing light LO is The direction of movement can be changed in the opposite direction by the prism 16b. Therefore, the P-polarized light component light Lp2 and the S-polarized light component light LS2 are emitted from the first polarizing prism group 16.
The angle (declination angle) formed by the optical axis O with respect to the optical axis O is δp2. δS2
Then, δp2. δs12 is approximately expressed by the following equation.

P polarization polarization angle; δI)2=γ(ne-1) γ(no-1
) = γ(ne -nO)...■ S polarization angle; δs2=γ(nσ-1) γ(ne-1) γ(no -ne)...■ Now, in this example, the sixth As shown in the figure, a second polarizing prism group 17 having the same configuration as the first polarizing prism group 16 is placed in front of the first polarizing prism group 16 (on the right side in the figure) with an optical axis O. are arranged in common. The first and second polarizing prism groups 16 and 17 are configured to be relatively rotatable about the optical axis 0 in opposite directions. Now, as shown in FIG. 6, these first polarized lights are based on the case where the crystal axes of the corresponding unit polarizing prisms of the first polarizing prism group 16 and the second polarizing prism group 17 are the same. Prism group 16
Consider a case where the polarizing prism group 17 and the second polarizing prism group 17 are relatively rotated by an angle W. Then, the polarization angles formed by the optical axis O and the P-polarized light component light Lp3 and the S-polarized light component light LS3 emitted from the second polarizing prism group 17 are δp3, respectively.
and δS3, δp3 and δS3 are respectively expressed by the following equations.

P polarization angle; δp3 = 27COs w (ne -no) - ■S
Polarization angle; δs3= 2'7CO3w (no -ne) ・-
As is clear from the equations ■■ and ■, when w = O° (the 6th
In the case shown in the figure), the argument angle is maximum, and as W approaches 90°, the argument decreases, and becomes 0 at w=90'. In Figure 7, W is approximately 90' and the declination is approximately 0.
This shows the case of In this case, both the P-polarized light Ll)3 and the S-polarized light Ls3 travel in a direction substantially parallel to the optical axis, and are not separated but travel as one light beam.

Both the P-polarized light component Lp3 and the S-polarized light component LS3, which are split by passing through the polarizing prism groups 16 and 17 described above, enter the condenser lens system 13, and due to the condensing action of the condenser lens system 13, They are focused on points A3 and A4 on the workpiece 14, respectively. In this case, the distance between A3 and A4 is determined by the angle W formed by the first and second polarizing prism groups 16 and 17, and when w=0, the first
As shown in the figure, when the distance between A3 and A4 is maximum and W is approximately 90°, A3
, A4 becomes almost 0.

Note that this condensing lens system 13 is usually composed of a plurality of lenses to prevent various aberrations and the like from occurring. In this example, lens 13a.

It is composed of four lenses 13b, 13c and 13d.

According to the above embodiment, by relatively rotating the first polarizing prism group 16 and the second polarizing prism group 17, the distance between the focal points A3 and A4 on the workpiece 14 can be increased. It can be set at any time within a predetermined range.

Furthermore, by rotating and adjusting the 174-wavelength plate 15, the energy ratio at the focal points A3 and A4 can be changed, so it is also possible to make the energy ratios at the two points exactly the same. Moreover, since the laser beam LO is split by a group of polarizing prisms, and each of the split polarized lights is focused by a single condensing lens system, the entire laser beam LO can be effectively used as processing energy, and the multi-lens A part of the laser beam LO is not wasted unlike the conventional case where the laser beam LO is used.

In addition, in the above-mentioned embodiment, the laser beam is split into two,
Although an example has been given in which the workpiece is processed at two points at the same time by focusing on two points on the workpiece, the present invention is not limited to this. By branching and focusing, it is also possible to simultaneously machine three or more force points on the workpiece by branching into three or more and focusing on three or more points on the workpiece.

Further, in the above embodiment, a Wollaston polarizing prism (first and second polarizing prism groups) is used as the polarization angle means.
Although an example using this polarization angle means is given, other polarization angle means such as a Senarmont type or a Glanlaser type may be used as the polarization angle means.

In short, the polarization angle means may be any means that can split the laser beam into a P polarization component and an S polarization component. Also,
Although an example using a 174-wavelength plate has been given as the phase difference changing means, for example, an electro-optical element such as a Faraday Rocheetah or other phase difference changing means may also be used. Note that if the laser beam emitted from the laser beam generating means is randomly polarized, the laser beam can be branched without using the phase difference changing means (174 wavelength plate).

[Effects of the Invention] As described above in detail, the present invention uses the polarization deflection means to change the traveling direction of the P-polarized component of laser light and the S
By making the traveling directions of the polarized light components different from each other, the light is branched into a plurality of parts, and each of these is focused on the workpiece by a condensing means, so that multiple parts of the workpiece can be processed at the same time, By using a polarization angle means that can vary the angle formed by the traveling direction of the P-polarized light component and the traveling direction of the S-polarized component light, it is possible to vary the distance between the plurality of processing points, and furthermore By passing the laser beam incident on the polarization angle means through a phase difference changing means that can vary the difference between the phase of the P-polarized light component and the phase of the S-polarized light component, the P-polarized light component and the S-polarized light component are separated. The energy ratio of the laser beam at multiple processing points can be varied by changing the energy ratio of the polarized light component.This allows the laser beam to be efficiently focused on multiple processing points without using multiple lenses. We have developed a laser processing device that makes it possible to perform desired processing on multiple processing points at the same time, and also allows the energy ratio of multiple focusing points and the interval between focusing points to be set relatively freely. That's what you're getting.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a laser processing device according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a conventional laser processing device, and FIG. 3 is an explanatory diagram of the operation of the conventional laser processing device. Fig. 3(a) is a diagram showing the intensity distribution of the Gaussian beam, Fig. 3(b) is a diagram showing the relationship between the multi-lens and the beam shape of the laser beam LO, and Fig. 4 is a diagram showing the relationship between the multi-lens and the beam shape of the laser beam LO. Fig. 5 is an explanatory diagram of the action of the first polarizing prism group, Figs. 6 and 7 are explanatory diagrams of the action of the first and second polarizing prism groups, and Fig. 8 is a diagram of changing the focal point interval. FIG. DESCRIPTION OF SYMBOLS 11... Laser device, 13... Condensing lens system which constitutes a condensing means, 14... Workpiece, 15... 174 wavelength plate which constitutes a phase difference changing means, 16.17... - First and second polarizing prism groups forming the polarization deflection means.

Claims (3)

[Claims] (1) A laser that simultaneously performs laser processing on multiple locations on the workpiece by dividing the laser light emitted from the laser light generating means into multiple light beams and focusing them on multiple locations on the workpiece. In the processing device, a polarization angle means for making the traveling direction of the P-polarized light component of the laser light emitted from the laser light generating means different from the traveling direction of the S-polarized light component light; S
What is claimed is: 1. A laser processing apparatus comprising: condensing means for converging each of the polarized light components onto a workpiece. (2) The laser processing apparatus according to claim 1, wherein the polarization angle means is capable of varying the angle formed by the traveling direction of the P-polarized light component and the traveling direction of the S-polarized light component. Laser processing equipment. (3) In the laser processing apparatus according to claim 1, there is provided a position between the laser beam generating means and the polarization angle means that can vary the phase difference between the phase of the P-polarized light component and the phase of the S-polarized light component. A laser processing apparatus characterized in that the energy ratio of P-polarized light component and S-polarized light component is made variable by interposing a phase difference changing means.