DE102010038572A1 - Apparatus and method for beam shaping - Google Patents

Abstract

A device is provided for beam shaping (1) with a plurality of light sources (21, 22, 23, 24) arranged next to one another, each of which has a first and a second reflection element (101, 102, 103, 104; 111, 112, 113, 114) are assigned and each emit a ray bundle (51, 52, 53, 54) along an emission direction, the emitted ray bundles (51-54) lying in an emission plane, running parallel to one another and the reflection elements (101-104; 111-114) are arranged in such a way that the emitted beams (51-54) each reflect on the assigned first reflection element (101-104) to the assigned second reflection element (111-114) and are reflected again by the latter and those from the second reflection elements (111-114) coming bundles of rays run parallel to each other and form a common emerging beam (12) that is neither parallel nor perpendicular when viewed in a vertical projection onto the radiation plane to the direction of radiation.

Description

The present invention relates to a device for beam shaping of the beam of several light sources whose emitted radiation beam parallel to each other, and a corresponding method for beam shaping.

Such a device is for example from the DE 197 80 124 B4 known, wherein the top of the heat sink is stepped, so that the juxtaposed light sources (here laser elements) emit their beams each at different heights. These beams are then deflected with deflecting mirrors by 90 ° so that the individual beams lie directly above each other and form a common beam.

A disadvantage of this structure is on the one hand, that due to the stepped design of the heat sink, the heat dissipation is very inhomogeneous. There may be temperature differences of 1 to 4 ° C and more from stage to stage. At a temperature dependence of the wavelength of the laser radiation of about 0.4 nm per ° C and a bandwidth of the emitted laser radiation of 3 to 4 nm, this leads to a significant and undesirable shift in the wavelength of the beam.

On the other hand, the production of such a stepped top of the heat sink is very expensive and only possible with an accuracy of about a few 10 microns.

From the US 6,229,831 B1 a device for beam shaping is known in which the individual light sources (in this case laser elements) are arranged via wedge elements on a planar upper side of a heat dissipation body. The wedge elements are chosen so that the inclination of the upper side is compensated relative to the horizontal, so that the individual laser elements emit their beams in the horizontal direction.

In this embodiment, the adjustment by means of the wedge elements is expensive. Also, the heat dissipation due to the wedge members in each individual laser element is uneven, which is disadvantageous. In addition, the heat dissipation is degraded by the additional joints in the heat transfer path.

Proceeding from this, it is an object of the invention to provide an improved apparatus for beam shaping. Furthermore, a corresponding method for beam shaping is to be provided.

The object is achieved by a device for beam shaping with a plurality of juxtaposed light sources, each of which a first and a second reflection element are assigned and each emit a beam along a radiation direction, the emitted beams lie in a plane of abstraction, parallel to each other and the reflection elements are arranged so that the emitted radiation beams each reflected at the associated first reflection element to the associated second reflection element, are reflected by this again and the coming of the second reflection elements beams parallel to each other and form a common outgoing beam, seen in the vertical projection on the Abstrahlebene neither parallel nor perpendicular to the emission direction.

In the beam shaping apparatus of the present invention, the light sources can be arranged on a planar portion of an upper surface of a heat dissipation body, so that excellent and homogeneous heat dissipation is possible. Furthermore, the size of the planar portion can be kept relatively low, so that the required footprint for a beam shaping device according to the invention can be kept small. Thus, an extremely compact beam shaping device according to the invention can be provided.

Preferably, the beam-shaping device comprises a heat-dissipating body with a top side, which has a planar section, on which the laser elements are arranged (preferably directly).

The planar or planar section of the upper side can be designed in particular as a continuous section. However, it is also possible that, for example, recesses are formed in the upper side between the juxtaposed laser elements, which result in that the planar section between the light sources is interrupted. It is preferable that the portions of the top surface of the heat sink on which the light sources are positioned lie in the same plane and thereby form the planar portion. It is further preferred that the planar portion is formed as a continuous or contiguous portion of the top.

The light sources may in particular be laser elements and / or LED elements. The radiation emitted by the light source can be in the visible range, in the infrared range or in the UV range, so that the light source can also be referred to as a radiation source.

In the beam-forming device according to the invention, the common (according to principle the device) precipitating beam preferably parallel to the plane section. Seen in cross section, the emergent beam may have a rectangular envelope or a parallelogram envelope.

The emergent beam can, viewed in perpendicular projection on the Abstrahlebene, with the emission of the emitting light source include an angle which is between 0 ° and 90 °. This angle can also be referred to as the azimuth angle.

In the beam shaping device according to the invention, neither the first reflection elements nor the second reflection elements are preferably arranged offset to one another in the emission direction. In particular, they are each arranged on a line, wherein the two lines can be parallel to one another. In each case, the reflection points of a central ray of the respective ray bundle can be considered as reference points.

In the beam shaping device according to the invention, the first reflection elements can be arranged so that the beams reflected at the reflection elements extend obliquely to the radiation plane. In particular, in each case the direction of the radiation beam incident on the first reflection element and the direction of the radiation beam reflected by the first reflection element can span a plane which is not perpendicular to the radiation plane.

Further, the second reflection elements can be arranged so that in each case the direction of the beam incident on the second reflection element and the direction of the beam reflected by the second reflection element span a plane which is not perpendicular to the radiation plane.

Furthermore, the second reflection elements, viewed in plan view of the radiation plane, can each be arranged directly above the associated first reflection element. However, it is also an offset possible.

The first reflection elements can cause a deflection of the emitted radiation beams in the range of 60 ° to 120 °. These deflected beams can then be deflected by means of the second reflection elements in the range of 60 ° to 120.

Furthermore, the first and second reflection elements can each cause a deflection about a first or a second axis, wherein both axes include an angle from the range of 60 ° to 120 °, in particular of 90 °.

The first and second reflection elements can be arranged in the beam shaping device according to the invention so that the emergent beam is parallel to the radiation plane. However, it is also possible that the emergent beam does not run parallel to the radiation plane.

In the case of the beam-shaping device according to the invention, at least two of the first reflection elements and / or at least two of the second reflection elements can each be formed as a continuous component. For example, the reflection elements may be formed as individual surfaces of a copper mirror component. Of course, the reflection elements may also be separate elements.

The heat dissipation body may consist of a highly thermally conductive material, in particular copper or a copper alloy or aluminum or a composite material or have this. The reflection elements can be designed as metallic surfaces or as metallic or dielectric layers on a carrier material.

Preferably, the beam-shaping device has an optical focusing element which focuses the beam reflected by the second reflection elements. The focusing element is preferably refractive and may have one or more elements. Thus, for example, the coupling of the laser radiation in an optical fiber with, for example, round or rectangular, especially for example square cross section possible.

For each light source between the light source and the associated first reflection element, the device can have at least one first optical element for collimating the radiation beam (eg in the fast-axis). The first optical element may be formed as a cylindrical lens or as a rotationally symmetrical lens. The lenses may be realized separately or, particularly in the form of cylindrical lenses, as individual segments of a coherent body. A rotationally symmetrical lens is advantageously designed as Kollimationselement for the fast-axis, while in the slow-axis because of the linear nature of the light or radiation source when using z. B. a semiconductor laser element even after the first optical element still a divergence is present.

Furthermore, the device can have at least one second optical element for collimation (for example in the slow axis) for each light source between the light source and the associated second reflection element.

The device may be configured so that the optical path from each light source to the associated second optical element is the same.

In the beam-shaping device, the wavelength of the emitted beam may be in the range of about 190 nm to about 2000 nm, especially in the range of 250 nm-2000 nm and in particular in the range of 600 nm to 1500 nm.

The laser elements are preferably semiconductor laser elements or laser diodes. The laser elements may be formed as separate laser elements and / or as laser bars. The laser elements are preferably designed as broad-band emitters, which emit a single-mode in fast-axis and multimode in slow-axis radiation. The laser resonators of these multimode laser elements are preferably designed as planar waveguides. The light exit surfaces of these laser elements represent linear beam sources.

By "parallel" is meant here in particular that as far as possible a mathematically exact parallelism is present. However, deviations in the single-digit range may be intentional or unintentional, which is still considered to be parallel. The heat-dissipating body can in particular be designed as a substantially plane-parallel plate or at least partially wedge-shaped.

The common outgoing beam has, seen in cross section, preferably an envelope, which is rectangular or square. Two or more of the beam-shaping device according to the invention may be provided such that the common outgoing beam bundles of the individual beam-shaping devices are superimposed to form a larger total beam. This can be realized for example for two beam-shaping devices by means of a partially transparent mirror or by means of a polarization-selective mirror which transmits a polarization direction and reflects a transmission direction orthogonal thereto. For this purpose, the present polarization of the respective common beam can be exploited. Of course, it is also possible to provide polarization-rotating elements, if necessary. Preferably, the polarization direction of the radiation of a beam-forming device is rotated by 90 °, while the polarization direction of the radiation of another beam-shaping device remains unchanged. Then, the beams of these two beam-forming devices can be combined with a polarization-selective mirror by one of the beams in transmission through the mirror passes you the other beam is reflected by an angle of preferably 90 ° to the mirror and the mirror paths of both beam-forming devices are superimposed after the mirror.

In the case of the beam-shaping device according to the invention, the beam or beams between the two reflection elements (ie the beam reflected by the first to the second reflection element) can coincide with the outgoing beam in a perpendicular projection onto the radiation plane.

There is further provided a method of beamforming the beams of a plurality of light sources (eg, laser elements and / or LED elements) each emitting a beam along a direction of radiation, wherein the emitted beams are in an abstraction plane and parallel to each other, wherein the Method of each of the emitted beams once around a first and then once deflected about a second axis so that the deflected beam parallel to each other and form a common outgoing beam, seen in perpendicular projection on the Abstrahlebene neither parallel nor perpendicular to the emission direction.

The inventive method can be further developed in a similar manner as the development of the device according to the invention.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention.

The invention will be explained in more detail for example with reference to the accompanying drawings, which also disclose characteristics essential to the invention. Show it:

1 a schematic side view of a first embodiment of the beam-forming device according to the invention;

2 a top view of the beam-forming device of 1 , where the lenses 9 are hidden;

3 a front view of the beam-forming device of 1 ;

4 a front view of a laser element of the device of 1 to 3 ;

5 a sectional view AA according to 2 ;

6 a schematic side view of a second embodiment of the beam-forming device according to the invention, and

7 a top view of the beam-forming device of 6 , where the lenses 9 are hidden;

In the in the 1 to 3 embodiment shown comprises the beam shaping device according to the invention 1 four light sources, here as semiconductor laser elements 21 . 22 . 23 and 24 are formed and in an x-direction side by side on a flat portion D of an upper side 3 a Wärmeableitkörpers 4 are arranged. In the embodiment described here, the entire top is 3 plan educated. However, this is not mandatory.

The laser elements 21 - 24 each give a laser beam 51 . 52 . 53 and 54 which runs in each case in the z-direction, so that the emission directions (in each case z-direction) of the individual laser elements 21 - 24 are parallel to each other and the emitted beams 51 - 54 lie in a level of abstraction, which is here parallel to the plane section D. The used laser elements 21 - 24 are all equally trained and each include, as in 4 for the laser element 21 shown is a waveguide 7 which has a perpendicular to the plane extending center line M and a rectangular cross-section. The height of the waveguide in the y-direction is approximately 3 μm and the width in the x-direction is approximately 100 μm. The emitted radiation beam here has a wavelength in the range of 630-1100 nm.

The emerging beam 51 typically has an elliptical beam cone (in the far field) in cross-section, with the minor axis extending in the x direction. This direction is often referred to as a slow axis, with the typical divergence angle in this direction often being about 7 to 15 degrees. The divergence angle in y-direction, which is often referred to as "fast axis", is typically 90 ° (the x, y, and z directions span a Cartesian coordinate system).

Since the emitter height along the y-direction of the laser element 21 - 24 is only a few microns, the emitted beam is by means of a first Kollimationslinse 81 . 82 . 83 . 84 with short focal length, which is often between 100 microns and 1,000 microns, very well collimated, so that the residual divergence of the beam after the first collimating lens 81 - 84 in the fast axis is very small. The first collimation lens 81 - 84 is preferred at a very short distance in front of the beam exit surface of the laser element 21 - 24 arranged as in the 2 and 3 is indicated.

Further, for each of the laser elements 21 - 24 another second collimation lens 91 . 92 . 93 and 94 , a first deflecting mirror 101 . 102 . 103 and 104 and a second deflecting mirror 111 . 112 . 113 and 114 intended. To simplify the illustration are in 2 the second collimation lenses 91 - 94 not marked and are in 3 only the laser element 24 with the associated further optical elements ( 84 . 104 . 94 . 114 ). The reflecting surface of the first deflection mirror 101 - 104 is preferably inclined by α = 45 ° with respect to the y-direction, as in 3 for the first deflection mirror 104 is drawn.

The first deflection mirrors 101 - 104 perform a deflection, so that the at the first deflecting mirrors 101 - 104 reflected beams 51 - 54 up ( 1 ). The direction of the tension on the respective deflection mirror 101 - 104 meeting the radiation beam 51 - 54 (ie the direction of radiation) and the direction of the respective deflection mirror 101 - 104 reflecting beam on a plane that is not perpendicular to the Abstrahlebene (xz-plane). One can also say that the reflected bundles of rays run diagonally to the plane of abstraction.

The thus deflected bundles of rays 51 - 54 each pass through the associated second collimator lens 91 - 94 , which performs a collimation of the slow-axis, and then hit the respective second deflection mirror 111 - 114 , which cause a deflection, so that the reflected beams 51 - 54 parallel to each other and parallel to the abstract plane. Together they form a failing bundle of rays 12 , whose cross section (section AA according to 2 ) in 5 is shown. The individual reflected beams 51 - 54 are arranged parallel to each other so that the envelope U1 is a rectangle. In plan view of the plane section D seen, the beam closes 12 with the emission direction (z-direction) an azimuth angle β between 0 ° and 90 ° (here about 80 °).

In the in the 1 to 3 shown embodiment, the second collimating lenses 91 - 94 each the same distance to the top 3 the Wärmeableitkörpers 4 on. After also the distance between laser element 21 - 24 and associated first deflecting mirror 101 - 104 for each laser element 21 - 24 is the same, this causes the optical path length for all beams 51 - 54 from the laser element 21 - 24 to the corresponding second collimator lens 91 - 94 is equal to. This is a very compact beam-forming device 1 provided, which has a very small footprint (size of the planar portion D) and at the outgoing beam 12 has a rectangular envelope.

It may further include a focusing lens 14 (dashed and only in 2 shown) for the beam 12 be provided, which serves to the failing beam 12 to focus, for example, in an optical fiber (not shown) to couple.

The optical fiber may have, for example, a round or rectangular, in particular a square core cross-section.

In 6 and 7 is a second embodiment of the beam-forming device according to the invention 1 shown, wherein like elements are designated by like reference numerals and reference is made to the description of the above statements. Since in the representation of 7 the first deflection mirrors 101 - 104 almost completely through the second deflecting mirrors 111 - 114 and the drawn ray bundles 51 - 54 are hidden, is only the first deflection mirror 101 marked with a reference numeral. In 7 are the lenses 9 not shown.

The embodiment according to 6 and 7 differs from the embodiment according to 1 to 3 in that the first deflecting mirror 101 - 104 are oriented so that they are the incident beams 51 - 54 deflects by 90 ° in the y-direction. Therefore, the second deflecting mirrors 111 - 114 directly above the respective associated deflection mirror 101 - 104 positioned. The second deflection mirror 111 - 114 are oriented so that the reflected beams are parallel to the plane section D, but not directly in the x-direction. Seen in a vertical projection onto the radiation plane, the reflected beam bundles can enclose an angle with the emission direction (z direction), which is preferably between greater than 0 ° and less than 90 °. This angle can be referred to as the azimuth angle β.

In this embodiment, envelope is the beam cross-section of the emergent beam 12 no longer rectangular, but parallelogram-shaped.

The deflection mirror 101 - 104 such as 111 - 114 may for example consist of solid metal material. It is also possible that the reflective surfaces of the deflecting mirror 101 - 104 . 111 - 114 are formed as metallic or dielectric layers on a carrier material.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19780124 B4 [0002]
• US 6229831 B1 [0005]

Claims (19)

Apparatus for beam shaping ( 1 ) with several juxtaposed light sources ( 21 . 22 . 23 . 24 ), each having a first and a second reflection element ( 101 . 102 . 103 . 104 ; 111 . 112 . 113 . 114 ) are assigned and each of a beam ( 51 . 52 . 53 . 54 ) along a radiation direction, wherein the emitted radiation beam ( 51 - 54 ) lie in an abstraction plane, run parallel to one another and the reflection elements ( 101 - 104 ; 111 - 114 ) are arranged so that the emitted radiation beams ( 51 - 54 ) each at the associated first reflection element ( 101 - 104 ) to the associated second reflection element ( 111 - 114 ) are reflected by the latter, which are reflected by the second reflection elements ( 111 - 114 ) coming parallel to each other and a common outgoing beam ( 12 ), which, when viewed perpendicular to the plane of abstraction, is neither parallel nor perpendicular to the emission direction. Apparatus according to claim 1, wherein the emergent beam ( 12 ) viewed in a vertical projection on the abstract plane with the emission direction encloses an angle which lies between 0 ° and 90 °. Device according to Claim 1 or 2, in which neither the first reflection elements ( 101 - 104 ) nor the second reflection elements ( 111 - 114 ) are arranged offset in the emission direction to each other. Device according to one of the preceding claims, in which the first reflection elements ( 101 - 104 ) are arranged so that in each case the direction of the on the first reflection element ( 101 - 104 ) incident beam ( 51 - 54 ) and the direction of the beam reflected by the first reflection element span a plane which is not perpendicular to the plane of abstraction. Device according to one of the preceding claims, in which the second reflection elements ( 111 - 114 ) are arranged so that in each case the direction of the on the second reflection element ( 111 - 114 ) incident beam and the direction of the second reflection element ( 111 - 114 ) reflected beam span a plane that is not perpendicular to the Abstrahlebene. Device according to one of the preceding claims, comprising a heat dissipation body ( 4 ), which has a top ( 3 ) having a planar portion (D), wherein the light sources ( 51 - 54 ) are arranged on the plane section (D). Device according to one of the preceding claims, in which the second reflection elements ( 111 - 114 ), seen in plan view of the Abstrahlebene, each above the associated first reflection element ( 101 - 104 ) are arranged. Device according to one of the preceding claims, in which the first reflection elements ( 101 - 104 ) cause a deflection in the range of 60 to 120 °. Device according to one of the preceding claims, in which the second reflection elements ( 111 - 114 ) cause a deflection in the range of 60 ° to 120 °. Device according to one of the preceding claims, in which the first and second reflection elements ( 101 - 104 . 111 - 114 ) are arranged so that the outgoing beam ( 12 ) runs parallel to the Abstrahlebene. Device according to one of the above claims, wherein at least two of the first reflection elements and / or at least two of the second reflection elements are each formed as a continuous component. Device according to one of the preceding claims, in which a focusing element ( 14 ) is provided which the outgoing beam ( 12 ) focused. Device according to one of the preceding claims, in which for each light source ( 21 - 24 ) between the light source ( 21 - 24 ) and the associated first reflection element ( 101 - 104 ) a first optical element ( 81 . 82 . 83 . 84 ) for collimation of the beam ( 51 - 54 ) is arranged. Device according to one of the preceding claims, in which for each light source ( 21 - 24 ) between the light source ( 21 - 24 ) and the associated second reflection element ( 111 - 114 ) at least one second optical element ( 91 . 92 . 93 . 94 ) for collimation of the beam ( 51 - 54 ) is arranged. Device according to Claim 14, in which the optical path of each beam ( 51 - 54 ) from the light source ( 21 - 24 ) to the associated second optical element ( 91 - 94 ) is equal to. Device according to Claim 14 or 15, in which the second optical element ( 91 - 94 ) between each of the first and second reflection elements ( 101 - 104 ; 111 - 114 ) is arranged. Device according to one of claims 1 to 13, wherein a third optical element in the beam path after the second reflection elements ( 111 - 114 ) is arranged, which in outgoing radiation beam ( 12 ) the radiation of the individual beam collimates. Device according to one of the preceding claims, in which the light sources ( 21 - 24 ) are formed as laser elements. A method of beamforming the beams of a plurality of light sources, each of which emits a beam along a radiation direction, wherein the emitted beams in an abstrahlebene and parallel to each other, wherein the method of each of the emitted beams once deflected by a first and then once around a second axis so is that the deflected bundles of rays parallel to each other and form a common outgoing beam, seen in perpendicular projection on the Abstrahlebene neither parallel nor perpendicular to the emission direction.

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