TWI821790B - Device for shaping a laser radiation - Google Patents

Abstract

An apparatus for shaping a laser radiation (7), comprising a first homogenizer (1) having a first array (2) of lenses (3) and a second homogenizer (4) having a second array (5) of lenses (6) through which the laser radiation (7) successively passes, a lens device (8) superimposing the laser radiation (7) passed through the second array (5) of lenses (6) in a working plane and a first prism (9) and a second prism (10) arranged between the second homogenizer (4) and the lens device (8), wherein the laser radiation (7) passed through the second array (5) of lenses (6) passes successively through the first and second prisms (9, 10) before impinging on the lens device (8).

Description

Devices that generate laser radiation

The present invention relates to a device for forming laser radiation, in particular to a linear intensity distribution of laser radiation, as in the general term of claim 1, and to a device for forming a linear intensity distribution of laser radiation as in the general term of claim 13. The intensity distribution of laser radiation is generated in the working plane, specifically a laser device used to generate the linear intensity distribution of laser radiation in the working plane.

In known devices for forming a linear intensity distribution of laser radiation, which comprise two homogenizers with a lens array and a Fourier lens, the length L of the linear intensity distribution results from the following relationship: , where p is the distance (spacing) between the centers of the parallel lenses of the array, f _H is the focal length of the lenses of the second array, and f _F is the effective focal length of the Fourier lens behind the second homogenizer. This amount is freely selectable during manufacturing but is fixed thereafter. Therefore, after fabrication, it is generally no longer possible to influence the line length or field size of the laser radiation in the working plane.

Devices of the above type and laser devices are known from DE 10 2007 026 730 A1. The apparatus described herein includes a first homogenizer stage having a lens array and a second homogenizer stage having two substrates, each of which has a lens array disposed thereon. A lens is further provided for superimposing part of the light beam emitted from the second homogenizer stage in the working plane, so that a linear intensity distribution of the laser radiation is generated there. In order to be able to adjust the line length of the linear intensity distribution, the two substrates of the second homogenizer stage can be moved relative to each other so that different distances in the light propagation direction can be achieved.

Since the two substrates of the second homogenizer stage can move relative to each other, the optical effectiveness of the device and the uniformity of the intensity distribution in the working plane are affected.

From this beginning, the invention is based on the problem of producing a device of the type mentioned at the outset, whereby more optical effectiveness of the device and/or a better uniformity of the intensity distribution in the working plane can be achieved. In addition, a laser device having this device will be described in detail.

According to the invention, this is achieved by a device of the type mentioned at the beginning having the characterizing features of claim 1 and by a laser device of the type mentioned at the beginning having the characterizing features of claim 13 to achieve. The sub-claims relate to preferred embodiments of the present invention.

According to claim 1, the device includes a first lens and a second lens arranged between the second homogenizer and the lens device, the device being adapted such that laser radiation passing through the second array of lenses impinges on the lens. The device passes through the first and second ridges in sequence. The insertion of two lenses between the second homogenizer and the lens arrangement has little or no effect on the optical effectiveness of the arrangement and on the uniformity of the resulting intensity distribution in the operating plane.

In particular, it may be provided that the pixels are arranged to at least partially reduce or increase the cross-section and/or divergence of the laser radiation passing through the pixels in the first direction, in particular wherein by the divergence By increasing, the length of the linear intensity distribution is increased, and by decreasing the divergence, the length of the linear intensity distribution is reduced. In particular, the linear intensity distribution thereby extends in a first direction.

Preferably, the laser beams may be configured to change the divergence of the laser radiation passing through the laser beams at least partially in the first direction by a factor between 0.5 and 2.0, in particular where the linear intensity The length of the distribution is thereby varied by a factor between 0.5 and 2.0. Therefore, the laser beam can be used to influence the shape of the intensity distribution and the length of the laser line generated in the working plane within a relatively large range.

It is possible that the lenses of the first array and the second array are arranged adjacent to each other. Specifically, the direction in which the lenses of the first array and the second array are arranged adjacent to each other corresponds to the first direction. In this regard, the lenses of the first and second arrays may be lenticular lenses having their cylindrical axes aligned parallel to each other, wherein the cylindrical axes extend in a second direction perpendicular to the first direction. In this way, the lens can promote homogenization in the longitudinal direction. It is conceivable to provide further cylindrical lenses in the homogenizer for the direction perpendicular to the transverse line, the cylindrical axes of which extend in the first direction.

Possibly, the first lens is arranged in the device in such a way that partial beams of laser radiation passing through adjacent lenses of the second array do not overlap each other at least in a first direction when entering the first lens, In this way, partial beams that have passed through individual lenses can be separated from each other.

It may be provided that at least one of the handles, preferably both handles, is movable, preferably pivotable about an axis. Thereby, the movement (pivot) of at least one lens changes a factor by which the cross-section of the laser radiation passing through the lens changes. In particular, the axis about which at least one, preferably both, of the handles is pivotable extends in the second direction. This design makes it very easy to affect the field size or line length of laser radiation in the working plane.

It is possible for two pigeons to have the same design, the same size and/or the same shape. Through this design, the manufacturing cost of the device can be reduced.

It may be provided that the distance between the lenses of the first array and the lenses of the second array corresponds to the focal length of at least some, preferably all, lenses of the second array. Furthermore, the lens device may be positioned in the device in a Fourier configuration such that the distribution of laser radiation existing in the angular space between the second array and the lens device is converted by the lens device into an intensity distribution in the three-dimensional space.

As with the device of claim 13, it may be provided that the device for forming the laser beam is a device according to the invention.

It is possible that the laser device comprises a laser beam configured to generate laser beams with mutually different properties, for example two laser light sources with mutually different divergences or beam profiles, wherein the laser device is configured such that the laser beams The irradiation is on devices adjacent to each other, and the lens device superimposes two laser beams in the working plane, specifically in a linear intensity distribution. It proves extremely advantageous if a single lens in a Fourier configuration is arranged in the working plane, in particular two possibly very different laser beams are superposed in a linear intensity distribution in the working plane, while the length of the line can be determined by Corresponding location specified.

For this purpose, it may be provided that the means for forming the laser beam comprise four beams, two of which are provided for each of the laser beams being different from each other.

Alternatively, provision may be made for the means for forming the laser beam to comprise two beams provided for two mutually different laser beams.

In the drawings, identical and functionally identical components are provided with the same reference symbols. In some drawings, a Cartesian coordinate system is drawn for better orientation.

The specific example of the device for forming a laser beam shown in FIG. 1 includes, in a manner known per se, a first homogenizer 1 with a first array 2 of lenses 3 and a second homogenizer 1 with a second array 5 of lenses 6 . Device 4. The device is configured for forming a laser beam 7 to pass through a first array 2 of lenses 3 and a second array 5 of lenses 6 in sequence.

The lenses 3 and 6 are arranged side by side in the first direction x. Lenses 3 and 6 are cylindrical lenses, the cylindrical axis of which extends in the direction y perpendicular to the first direction x, and the second direction y extends beyond the plane of FIG. 1 . The lenses 3, 6 therefore act in the first direction x. The laser beam 7 substantially moves in the third direction z perpendicular to the first direction x and the second direction y.

It is of course possible to provide spherical lenses or lenses of different shapes instead of cylindrical lenses, which act in both the first direction x and the second direction y.

In the figure, the first array 2 is arranged on the outlet surface of the first homogenizer 1 , and the second array 5 is arranged on the inlet surface of the second homogenizer 4 . It is possible to arrange both arrays 2 and 5 on the inlet surface or the outlet surface, or to arrange the first array 2 on the inlet surface of the first homogenizer 1 and the second array 5 on the outlet of the second homogenizer 4 On the surface. Furthermore, it may also be provided that only a single transparent substrate is provided, the first array 2 being arranged on the entrance surface of this substrate and the second array 5 being arranged on the exit surface of the substrate.

For example, other possibilities are that a lens array (not shown in the figure) is arranged on the incident surface of the first homogenizer 1 and/or is arranged on the exit surface of the second homogenizer 4, and these lenses act on the second homogenizer. direction y. For example, these lenses may be cylindrical lenses whose cylindrical axis extends in the first direction x.

All lenses 6 of the second array 5 have the same focal length. The distance between the two arrays 2 and 5 is equal to the focal length of the lens 6 of the second array 5 .

The device illustrated in Figure 1 further comprises, in a manner known per se, a lens arrangement 8, which in the particular example illustrated is formed as a plano-convex lens 8 in a Fourier configuration. The lens arrangement 8 superimposes, in a manner known per se, partial beams of laser radiation 7 emitted from the lenses 6 of the second array 5 in a first direction x in the working plane, not shown in the figure. Thereby, the distribution of laser radiation in the angular space is converted into the distribution in the three-dimensional space in the working plane.

It is of course possible to provide lenses of other shapes, such as lenticular lenses. Additionally, lens systems may be provided instead of individual lenses.

The device illustrated in Figure 1 further comprises two lenses 9, 10 between the second homogenizer 4 and the lens arrangement 8 through which the laser radiation 7 passes in sequence. In the specific example embodiment illustrated, the handles 9, 10 have the same size and the same shape, and the cross-section apparent in Figure 1 continues into the extended plane of Figure 1 .

The first lens 9 on the left side in Figure 1 is such that when the laser radiation 7 is irradiated on the incident surface 11 of the first lens 9, the part of the laser radiation 7 that has passed through the adjacent lens 6 of the second array 5 The beams are configured in such a way that they do not overlap each other in the first direction x.

By suitable alignment of the lenses 9, 10, a change in the cross-section and/or divergence of the partial beams emitted from each of the lenses 6 can be achieved, in particular equally for each of the partial beams. . The following applies to the change: D _in · F _in = D _out · F _out , where D _in is the range of the partial radiation entering the first direction x in the three-dimensional space, and F _in is in the angular space The range of partial radiation entering the first direction x, D _out is the range of the partial radiation leaving the first direction x, 10 in the three-dimensional space, and F _out is the range in the angular space The range of the partial radiation emitted from the radiators 9 and 10 in the first direction x.

Figure 2a shows in the left figure respectively the cross-section 12a and the range Din of the partial radiation entering the holes 9 and 10 in the first direction x in the three-dimensional space. Figure 2a shows in the right figure respectively the divergence 13a and the range Din of the partial radiation entering the radiators 9 and 10 in the first direction x in the angular space.

Figures 2b and 2c illustrate the influence of two different positions of the casings 9 and 10 on the partial radiation emitted from the casings.

2b shows separately in the left figure a cross section 12b of the range D _out of the partial radiation emitted from the lenses 9 and 10 in the first direction x in the three-dimensional space. FIG. 2b shows separately in the right figure the divergence 13b in the angular space in the first direction x in the range outside the partial radiation emitted from the lenses 9, 10. It can be seen that the divergence 13b is smaller than the divergence 13a. The smaller divergence 13b or the smaller expansion in the angular space is converted by the lens device 8 into a distribution in the three-dimensional space in the working plane, resulting in a smaller spreading of the field in the working plane in the first direction x, in particular The smallest length of the linear intensity distribution.

FIG. 2 c shows a cross section 12 c of the range D _{out of} the partial radiation emitted from the detectors 9 , 10 in the first direction x in three-dimensional space in the left figure alone. FIG. 2c shows separately in the right figure the divergence 13c in the angular space in the first direction x in the range outside the partial radiation emitted from the lenses 9, 10. It can be seen that the divergence 13c is greater than the divergence 13a. The lens device 8 converts a large divergence 13c or a large expansion of the angular space into a distribution in the three-dimensional space in the operating plane, thereby resulting in a large expansion of the field in the operating plane in the first direction x, in particular The maximum length of a linear intensity distribution.

In Figures 3a to 4b this is illustrated by a specific example embodiment of a device for forming a linear intensity distribution 14 of laser radiation in the working plane.

Figure 3a shows the device with the handles 9, 10 in a first position. In this first position, the length of the linear intensity distribution 14 is slightly greater than 700 mm, as can be seen from Figure 3b.

Figure 4a shows the same device as in Figure 3a. However, in Figure 4a, the handles 9, 10 are in a second position different from the first position. In this second position, the length of the linear intensity distribution 14 is approximately 500 mm, as can be seen in Figure 4b.

Different positions of the handles 9, 10 can be achieved by pivoting the individual handles 9, 10 about an axis extending in the second direction y. For example, in the position shown in Figures 3a and 4, the first housing 9 in Figure 4a pivots clockwise relative to the housing 9 in Figure 3a about a corresponding axis extending in the second direction y. Furthermore, in the position shown in Figures 3a and 4, the second housing 10 in Figure 4a pivots counterclockwise relative to the housing 9 in Figure 3a about a corresponding axis extending in the second direction y.

Figure 5 shows a specific example of a device according to the invention, which device differs from the device in Figure 1 in that four cams 9a, 9b, 10a, 10b are provided instead of two cams 9, 10. Here, the two first beams 9a and 9b are arranged side by side in the first direction x. In addition, the two second frames 10a and 10b are arranged in close proximity to each other in the first direction x.

For example, two laser beams 7a, 7b that differ from each other by their divergence or beam profile are illuminated on the device. The first laser beam 7a is irradiated on the upper area of the first homogenizer 1 in Figure 5, and the second laser beam 7b is irradiated on the lower area of the first homogenizer 1 in Figure 5.

The means are thereby arranged so that the laser radiation 7a which has passed through the upper first casing 9a in Figure 5 then passes through the upper second casing 10a in Figure 5 and, in addition, has passed through the lower first casing 9a in Figure 5 The laser radiation 7b of the first laser beam 9b then passes through the second lower laser beam 10b in Figure 5. Furthermore, the device is arranged so that the two laser beams 7a, 7b that have passed through the second lens 10a, 10b pass together through the lens device 8 and are superimposed by them in the working plane, in particular in a linear intensity distribution.

It proves extremely advantageous that a single lens arrangement 8 in a Fourier configuration superimposes two possibly very different laser beams 7a, 7b in a linear intensity distribution in the working plane, while the length of the line It can be predetermined by the corresponding positions of the handles 9a, 9b, 10a, and 10b.

It can be provided that the homogenizers 1, 4 have different design areas for different laser beams 7a, 7b which are adjacent or spaced apart from each other in the first direction x.

In other possible systems, the device for forming two different laser beams 7a, 7b does not contain four laser beams, but only two (not shown in the figure) laser beams. In this case, these laser beams are Provision is made for two of the different laser beams 7a, 7b.

Other possibilities are that, in the specific examples illustrated in Figures 1, 3a, 4a and 5, other lenses are provided for focusing the laser radiation or such laser radiation into the working plane and/or for focusing relative to The second direction y forms laser radiation or such laser radiation. Where applicable, these lenses are not shown for reasons of clarity.

1: First homogenizer 2: First array 3: Lens 4: Second homogenizer 5: Second array 6: Lens 7:Laser beam 7a:Laser beam 7b:Laser beam 8: Lens device 9:稜顡 9a:稜顡 9b:稜顡 10:稜顡 10a:稜顡 10b:稜顡 11:Incidence surface 12a: Cross section 12b: Cross section 12c: Cross section 13a: Divergence 13b: Divergence 13c: Divergence 14: Linear intensity distribution

Other features and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Shown in this article: [Fig. 1] is a schematic side view of a first specific example of a device according to the present invention, in which a beam of laser radiation to be formed has been introduced; [Fig. 2a] are two diagrams schematically illustrating the distribution of laser radiation in three-dimensional space and in angular space behind the second homogenizer; [Fig. 2b] are two diagrams schematically illustrating the distribution of laser radiation behind the second lens in the three-dimensional space and in the angular space in the first position of the two lenses; [Fig. 2c] Two diagrams schematically illustrating the distribution of laser radiation behind the second lens in the three-dimensional space and in the angular space in the second position of the two lenses; [Fig. 3a] is a schematic side view of the specific example of Fig. 1 in the first position of the two handles; [Fig. 3b] is a diagram in which the intensity of laser radiation in the operating plane is plotted in arbitrary units with respect to the spatial coordinate in the longitudinal direction of the line of linear intensity distribution in mm, in which the two beams are shown in Fig. 3a Shown in the first position; [Fig. 4a] is a schematic side view of the specific example of Fig. 1 in the second position of the two handles; [Fig. 4b] is a diagram in which the intensity of laser radiation in the operating plane is plotted in arbitrary units with respect to the spatial coordinate in the longitudinal direction of the line of linear intensity distribution in mm, and two pixels are shown in Fig. 4a in the second position; [Fig. 5] is a schematic side view of a second specific example of the device according to the present invention, in which a beam of laser radiation to be formed has been introduced.

1: First homogenizer

2: First array

3: Lens

4: Second homogenizer

5: Second array

6: Lens

7:Laser beam

8: Lens device

9:稜顡

10:稜顡

11:Incidence surface

Claims (16)

A device for forming laser radiation (7, 7a, 7b), comprising: a first homogenizer (1) comprising a first array (2) of lenses (3), said device being configured to use The laser radiation (7, 7a, 7b) to be shaped passes through the lenses (3) of the first array (2), the second homogenizer (4) having the lenses (6) of the second array (5) ), said device being configured for passing laser radiation (7, 7a, 7b) that has passed through the lenses (3) of the first array (2) through the lenses (5) of the second array (5) 6) Lens means (8) configured for passing said laser radiation (7, 7a, 7b) having passed through the lenses (6) of said second array (5) through said Lens arrangement (8) such that at least part of the beams of laser radiation (7, 7a, 7b) that have passed through some of the lenses (6) of the second array (5) are superimposed in the working plane, wherein the The device includes a first lens (9, 9a, 9b) and a second lens (10, 10a, 10b) arranged between the second homogenizer (4) and the lens device (8), so The device is configured such that the laser radiation (7, 7a, 7b) passing through the lenses (6) of the second array (5) passes through the lens assembly (8) in sequence before impinging on the lens device (8). The first frame and the second frame (9, 9a, 9b, 10, 10a, 10b). The device of claim 1, wherein said laser beams (9, 9a, 9b, 10, 10a, 10b) are configured to reduce or increase said laser radiation (7) at least partially passing through said laser beams. , 7a, 7b) cross section (12a) and/or divergence (13a) in the first direction (x). The device of claim 2, wherein the laser beam (9, 10) is configured to direct the laser radiation (7, 7a, 7b) at least partially passing through the laser beam in the first direction. (x) The divergence (13a) above changes by a factor between 0.5 and 2.0. The device according to any one of claims 1 to 3, wherein the lenses (3, 6) of the first array (2) and the second array (5) are respectively arranged adjacent to each other. The device according to any one of claims 1 to 3, wherein the first array (2) and the The lenses (3, 6) of the second array (5) are cylindrical lenses, and the cylindrical axes of the lenses are aligned parallel to each other. The device of claim 2 or 3, wherein the first lens (9, 9a, 9b) is such that the laser radiation that has passed through the adjacent lens (6) of the second array (5) The partial beams of (7, 7a, 7b) are arranged in the device in such a way that they do not overlap each other at least in the first direction (x) when they enter the first beam (9, 9a, 9b). The device of any one of claims 1 to 3, wherein at least one of the handles (9, 9a, 9b, 10, 10a, 10b) is movable. The device of claim 7, wherein the movement of the at least one cam (9, 9a, 9b, 10, 10a, 10b) changes through the cam (9, 9a, 9b, 10, 10a, 10b) The factor by which the cross-section of the laser radiation (7, 7a, 7b) is changed. The device of claim 7, wherein the axis about which at least one of the handles (9, 9a, 9b, 10, 10a, 10b) is pivotable extends in the second direction (y). The device according to any one of claims 1 to 3, wherein the two handles (9, 9a, 9b, 10, 10a, 10b) have the same design. The device according to any one of claims 1 to 3, wherein the distance from the lens (3) of the first array (2) to the lens (6) of the second array (5) corresponds to The focal length of at least some lenses (6) of the second array (5). A device as claimed in any one of claims 1 to 3, wherein said lens means (8) are positioned in said device in a Fourier configuration so as to exist between said second array (5) and said lens means The distribution of the laser radiation (7, 7a, 7b) in the angular space is converted into an intensity distribution in the three-dimensional space by the lens device (8). A laser device for generating intensity distribution of laser radiation (7, 7a, 7b) in a working plane, which includes at least one laser light source and a device for forming laser radiation (7, 7a, 7b) Device, wherein said device for forming laser radiation (7, 7a, 7b) is a device according to any one of claims 1 to 12. The laser device of claim 13, wherein the laser device comprises two laser light sources configured to generate laser radiation (7a, 7b) with mutually different properties, wherein the laser device is configured for After the laser radiation (7a, 7b) is irradiated on the device for forming the laser radiation (7, 7a, 7b), and the lens device (8) is superimposed in the working plane Two laser radiations (7a, 7b). The laser device of claim 14, wherein the device for forming laser radiation (7, 7a, 7b) includes two first laser beams and two second laser beams (9a, 9b). , 10a, 10b), one of the two first laser beams and one of the two second laser beams are in each case provided for mutually different laser radiation (7a , one of 7b). The laser device of claim 14, wherein the device for forming laser radiation (7, 7a, 7b) includes the first laser beam and the second laser beam, and the first laser beam and the second laser beam are The second lens is provided for two of the laser radiations (7a, 7b) that are different from each other.