DE102007002498A1 - Laser beam generating device for projecting e.g. image, has deflecting mirrors arranged and aligned within laser diode groups such that deflected individual beams are led parallely and close to each other - Google Patents

Abstract

The device has a set of laser diodes (2) for generating individual beams and integrated to a set of laser diodes groups (3). Each laser diode is assigned with a deflecting mirror (5), where the deflecting mirrors are arranged and aligned within the laser diode groups such that the deflected individual beams are led parallely and close to each other. Two partial beams (8, 12) are linearly polarized and have same polarization direction. The polarization direction of the partial beam (12) is rotated around 90 degrees. A terminal die combines the two partial beams to a total beam (16). An independent claim is also included for a method for generating a laser beam.

Description

The The invention relates to a device for generating a laser beam with the multiple power of a semiconductor laser diode, in particular a laser beam used for show purposes. It concerns further a method for producing such a laser beam.

In the prior art so-called DPSS laser are known, which have a high energy consumption. These lasers have a radiation maximum at a wavelength of approximately 671 nanometers. This wavelength is close to the infrared region of the light spectrum, so that visible light to the eye can only be produced with such a laser at a high power. The US Pat. No. 6,687,271 illustrates how to operate such a laser with high power density.

The DE 200 10 309 U1 , the WO 03/098758 A1 and the WO 98/13910 describe diode laser arrangements, with which the laser beams can be coaxially superimposed by a plurality of diode lasers. It is disadvantageous that in the coaxial superimposition of the laser beams by dichroic mirror power is lost, especially when the laser beams are already no longer monochromatic by mixing.

In the US 5,463,534 An optical system for generating a light source is described in which a plurality of laser beams are combined. For this purpose, a relatively complex optics with several anamorphic prisms is used.

task The invention is therefore a technically simple device to provide for the production of laser light, which can be produced inexpensively and operable and also flexible usable and their laser beam especially for Show purposes is suitable.

Furthermore It is another object of the present invention to provide a method to provide a laser beam.

According to the invention this Problem solved with the subject of the independent claims. advantageous Further developments of the invention are the subject of the dependent claims.

A inventive device for generating a laser beam has a plurality of laser diodes, each generate a single beam and to a number of laser diode groups are summarized on. The device comprises at least two such laser diode groups. Each laser diode is associated with a deflection mirror, wherein within a laser diode group the deflection mirrors are arranged and aligned such that the deflected single beams of the laser diode group parallel and so close to each other are that they form a group beam.

There the device according to the invention It also generates at least two laser diode groups two group beams. The group beams can with a designated Combined device to a first and a second partial beam become. If the device comprises only two laser diode groups, the two group beams already correspond to the two partial beams.

There Laser diodes generate light that is largely linear, in parallel to the active zone of the diode, polarized, are the first and the second sub-beam each both horizontally or both vertically polarized.

It is therefore further a device for rotation of the polarization direction of the second partial beam provided by 90 degrees, so that a rotated Partial beam is created. Since the two partial beams, the first partial beam and the second, now rotated in its polarization partial beam have different polarizations, wherein a partial beam for example, vertical and the other is horizontally polarized, is a pole cube to the merge of the first partial beam with the rotated second partial beam to a Overall beam provided.

The Invention goes from consideration from that, a particularly inexpensive to produce and operable and at the same time a particularly flexible device for generating a Laser beam combine the radiation of a plurality of laser diodes should. By combining the radiation of many laser diodes can be Create a laser beam of high performance easily and cheaply. at Failure of one or more laser diodes can replace them quickly and easily become. The device is thus easy to maintain and repair. In addition, by the mixture of laser beams different wavelength Rays with very different color effects for the human Create eye. This is especially for devices for production of laser beams for Show purposes such as in discotheques important where rays or pictures on surfaces or be projected into a room filled with smoke or steam.

The individual components of the device should therefore not be technically complicated and therefore expensive. Laser diodes can be purchased in different colors and performance classes and used in the device according to the invention the.

there comes the combination of their individual beams to a total laser beam one for the beam power of the device is important. There at the use of partially permeable Mirror for coaxial overlay of rays power is lost and such mirrors also expensive are, the invention goes a different way. First, the single rays the laser diodes of a laser diode group placed next to each other and thus at most one another partly superimposed. For this purpose, only deflecting mirrors are required, which are cleverer Be constructed so that the deflected single rays in parallel and lie close together and form a group beam.

Should this may be required but several group beams with the help of a mirror to a first and a second partial beam are combined. This will be then only a small number of such mirrors needed. Are only two laser diode groups present, correspond to the two resulting group beams anyway the two required partial beams.

For overlay of the two partial beams is a polarization cube, also called Polwürfel used, of two cemented together right angle prisms with a dielectric multilayer. He combines two linear polarized partial beams with 90 degrees twisted against each other Polarization directions to an unpolarized total beam. One such pole cubes has the advantage that it is unlike a dichroic mirror broadband can be used, so that the partial beams are not monochromatic and not approximate must be monochromatic.

In order for the pole cube to be used in the device according to the invention, there must first be two linearly polarized partial beams with polarization directions rotated relative to one another by 90 degrees. Since the laser diodes emit all linearly polarized light of the same polarization direction, the polarization of a sub-beam must be 90 degrees before merging into a total beam _. to be turned around. In principle, it would also be conceivable to rotate part of the laser diodes by 90 degrees, that is to tilt them to the side. However, to make such a structure stable, a considerable adjustment effort and installation effort is required.

Therefore the polarization direction of the second sub-beam is rotated prior to merging. For that there are different possibilities: In one embodiment the invention is for this polarization rotation used a λ / 2 plate, the the property has the polarization direction of linearly polarized Turn light 90 degrees.

at an alternative embodiment The invention is a mirror system for rotating the polarization direction intended. This mirror system can for example consist of two Spie rules exist, which are specially aligned with each other, the first Mirror the second partial beam to be rotated, for example, vertically deflects upwards while the second mirror redirects it to the horizontal to Z + 90 °. With such an arrangement leaves to achieve a rotation of the polarization direction by 90 degrees.

The Laser diodes can either emit all the light of the same wavelength, where by "the same wavelength" is meant that their wavelength maximum at the same wavelength lies.

It can However, laser diodes are also used, the light is different wavelength send out.

For example a number of the laser diodes can be designed as laser diodes, whose substrate has the elements P, In, Ga and / or Al and the "red" light with a wavelength from about 652 nm to about 664 nm, preferably from about 654 nm to about 662 nm with a maximum, preferably at 658 nm.

It can Also laser diodes are used, the "blue" light with a wavelength of about 401 nm to about 480 nm with a maximum in the wavelength at preferably produce about 445 nm, or the "green" light with a wavelength from about 505 nm to about 555 nm, preferably from about 520 nm to about 544 nm with a maximum in wavelength, preferably about 532 nm.

typically, It is necessary to use the individual, group and partial beams or at least collimating the entire beam, so collect and its Reduce beam cross-section to achieve a greater power density. For collimation of the first and second sub-beam and / or the Total beam is therefore advantageously provided a collimator.

An inventive method for generating a laser beam has the following steps: First, a plurality of individual beams is generated by a plurality of laser diodes. Subsequently, the individual beams of several laser diodes, which form a laser diode group, merged by means of deflecting mirrors to form a group beam, wherein within a laser diode array, the deflection mirrors are arranged and aligned such that the deflected single rays of the laser diode group are parallel and guided so close to each other that they form a group beam.

Several Group beams then become a first and a second partial beam combined, wherein the first and the second partial beam each both horizontally or both are vertically polarized. Before the first and the second sub-beam using a Polwürfels to a total beam together becomes, the polarization direction of the second sub-beam to Turned 90 degrees.

The inventive device and the method according to the invention have the advantage that they allow it to be very simple and easy inexpensive components to produce a laser beam of relatively high power, whose properties such as color and beam cross section are flexibly changed can and that's why, for example Show purposes is very well suited.

embodiments The invention will be described below with reference to the accompanying drawings explained in more detail.

1 shows an embodiment of the inventive apparatus for generating laser beams;

2 shows beam profiles of the laser beams according to 1 ;

3 shows a mirror system for polarization rotation.

The device 1 for generating laser beams according to 1 has a plurality of laser diodes 2 on. All laser diodes 2 can emit radiation of the same wavelength, but it is also possible to use laser diodes 2 emitting radiation of different wavelength in the device 1 to combine and mix their rays. The best way to see a dichroic color filter before, so as not to degrade the quality of the beam profile.

The laser diodes 2 are to several laser diode groups 3 summarized. In the embodiment according to 1 are in total 16 laser diodes 2 provided, leading to four laser diode groups 3 are summarized. The four laser diode groups 3 turn, form two sub-devices, namely the first sub-device 17 and the second sub-device 18 , However, it is also conceivable, more or fewer laser diodes 2 within a laser diode group 3 vorzuehzu to summarize within a sub-device. It is only expedient in the device according to the invention to provide a total of two sub-devices.

Every laser diode 2 generates a laser beam, the single beam 4 , This single beam is due to the characteristic of the laser diode 2 largely linearly polarized, for example horizontally polarized. The single beam 4 leaves the laser diode and strikes a deflection mirror 5 that redirects him. In the embodiment according to 1 are the deflection mirrors 5 arranged so that they deflect the individual rays just at a right angle. However, it is of course possible, depending on the space available for the device 1 also choose a different arrangement.

In this case, adjacent deflecting mirrors are arranged such that a deflected individual beam 6 just at the edge of the next in the beam direction deflecting mirror 5 sweeps past. In this way it is achieved that all single rays 4 a laser diode group 3 be placed parallel and as close together as possible to a group beam 7 to build. The group beam 7 is therefore not by coaxial combination of the individual beams 4 but created by juxtaposing them.

In the embodiment according to 1 are two laser diode groups per subdevice 3 intended. Thus, there are also two group beams per partial device 7 , To combine these into a partial beam is another deflection mirror 19 provided the one group beam 7 so divert that this with the other group beam 7 for example with the help of a mirror 9 can be combined to a sub-beam. In this way, the first part device generates 17 a first partial beam 8th and the second sub-device 18 a second partial beam 12 ,

The two laser diode groups 3 of the sub-devices 17 . 18 are each offset in height. This has the advantage that the two group beams 7 in a very simple way can be combined with each other to a sub-beam, without the power is lost. Advantageously, the laser diode groups of a sub-device are arranged offset in height to each other, so that the laser beams generated by them are indeed in mutually parallel planes, but offset in height by an offset distance from each other. This makes it very easy to combine the group beams: it is a mirror 9 provided, one of the group beams 7 while the other just turns over the mirror 9 sweeps. The offset distance or the arrangement of the mirror 9 must therefore be chosen so that a brief sweeping away of a group beam on the mirror 9 is possible right now. With this type of combination of the group beams into a sub-beam, no power is lost in contrast to the use of beam splitters.

In most cases, it is desirable to produce a laser beam of high intensity and with a small beam cross-section, and in particular with low divergence. These are collimators 10 intended as collection and bundling units. In this case, either only a single collimator can be arranged so that it the final laser steel 16 collimates, but also the single, group and / or partial beams can be collimated.

In the embodiment according to 1 are two collimators 10 provided in each case for the two partial beams. In this way, the two partial beams are already collimated, so that the use of the pole cube 15 No too much adjustment effort is necessary. On the other hand, however, only two collimators 10 needed and not more, as it would be the case if the single or group beams were already collimated. Thus, a relatively compact construction of the device 1 without superfluous components possible.

This would also be possible with a single collimator following the pole cube 15 located. However, a big pole cube is 15 more expensive than two collimators. The in 1 illustrated cubes 15 can also be much smaller than shown there.

The two collimated partial beams 8th . 12 be with the help of a pole cube 15 to a total beam 16 combined. The pole cube 15 enables a simple coaxial combination of the two partial beams and also produces a total beam with equal proportions of horizontal and vertical polarization at the same intensity partial beams.

However, the properties of the pole cube 15 to be able to use the two partial beams 8th . 12 have different polarization directions. Since all individual beams are horizontally polarized in this embodiment, the partial beams are also 8th . 12 horizontally polarized. It is therefore necessary to polarize one of the sub-beams 8th . 12 before the combination to turn 90 degrees.

This is in the embodiment according to 1 a device 13 intended for polarization rotation. This device 13 may be, for example, a λ / 2 plate. However, it is also possible to make the polarization rotation by a suitable mirror system. The device 13 generated from the second partial beam 12 with horizontal polarization a partial beam 14 with vertical polarization. This can now easily with the first part of the beam 11 in the pole cube 15 to a total beam 16 be combined.

The 2A to 2D show cross sections through beam profiles of the laser beams along the section lines AA, BB, CC and DD 1 in the event that the polarization rotation of the second partial beam, the mirror system according to 3 is used. The beam profiles CC and DD for the case that the polarization direction is made with the aid of a λ / 2-plate, are in the 2E and 2F shown.

2A shows a beam profile of the group beam 7 , This group beam 7 is composed of four individual beams, each due to their generation by the laser diodes 2 have an approximately elliptical cross section and with the help of the deflection mirror 7 parallel and close together.

2 B shows the beam profile of a collimated sub-beam 11 . 2C that of the collimated and through the mirror system 25 rotated second partial beam 14 , The total beam 16 whose beam profile is the 2D shows, arises from the merger of the first and the second partial beam. Its beam profile is therefore essentially an addition of the beam profiles from the 2 B and 2C ,

2E shows the beam profile of the collimated and rotated by a λ / 2-plate second partial beam 14 , The λ / 2 plate rotates in contrast to the mirror system only the polarization direction, but not the beam profile.

The mirror system 25 for polarization rotation according to 3 includes a first mirror 21 and a second mirror 23 , An incoming ray 20 which has a horizontal polarization and is incident horizontally in the x-direction is transmitted through the first mirror 21 distracted at a right angle. The deflected beam 22 falls in the z-direction on the second mirror 23 and in turn is distracted by this, so that the doubly deflected beam 23 oriented in the y-direction.

At the first mirror 21 becomes the polarization direction of the incident beam 20 not turned, at the second mirror 23 however, it is rotated 90 degrees so that the horizontal polarization becomes vertical. The resulting beam 24 points to the incident beam 20 a 90 degree rotated polarization direction. In addition, the beam profile at the second mirror 23 also rotated 90 degrees.

When using this or a similar mirror system 25 in the device 1 according to 1 is it possible the polarization of the second partial beam 12 to turn 90 degrees, so that the combination of both partial beams 8th . 12 the properties of the pole cube 15 can be used. It is also advantageous that the profiles of juxtaposed individual beams 4 , which is ultimately the second partial beam 12 form, also rotated 90 degrees, there in this way a more homogeneous overall jet 16 results.

Overall, the mirror system needed 25 for polarization rotation typically slightly more space than the structure using a λ / 2-plate. It must also be taken into account the fact that the doubly deflected beam 24 according to 3 in a different plane than the output beam, wherein the two planes are mutually parallel offset by the distance a. However, the compensation of this height difference can be done in a simple manner, for example, by the fact that the second sub-device 18 can already be built in a different height than the first sub-device 17 , This also brings with it the advantage that the available space can be better utilized by distributing the entire device on two levels.

To clarify the representations in 2 and in 3 the following is to be emphasized. The representation in 2C and 2D refers to the use of in 3 shown mirror system. If a λ / 2 plate or waveplate is used instead, then the polarization direction is changed, but not the beam profile. The individual beams are then not overlapping each other as in 2D but the individual beams are on top of each other, possibly slightly shifted relative to one another, so that, in spite of a crosswise polarization of the individual beams, a beam shape results which corresponds to that in FIGS 2A . 2 B . 2E or 2F equivalent.

Finally, it should be mentioned that the in 1 shown laser diodes 2 can also be executed in each case with an integrated collimator. Then you can do without a collimator in the further beam path depending on the purpose.

1

contraption for generating a laser beam

2

laser diode

3

laser diode array

4

single beam

5

deflecting

6

diverted single beam

7

group ray

8th

first partial beam

9

mirror

10

collimator

11

collimated first partial beam

12

second partial beam

13

contraption for polarization rotation

14

polarization rotated second partial beam

15

Polwürfel

16

total beam

17

first partial device

18

second partial device

19

Another deflecting

20

incident beam

21

first mirror

22

diverted beam

23

second mirror

24

doubly deflected beam

25

mirror system

a

distance

Claims (32)

Device for generating a laser beam, comprising: a plurality of laser diodes ( 2 ), each having a single jet ( 4 ) and generate a number of laser diode groups ( 3 ), wherein the device comprises at least two laser diode groups ( 3 ) having; A number of deflecting mirrors ( 5 ), wherein at least each laser diode ( 2 ) a deflection mirror ( 5 ) and within a laser diode group ( 3 ) the deflection mirrors ( 5 ) are arranged and aligned such that the deflected individual beams ( 4 ) of the laser diode group ( 3 ) are parallel and so close to each other, that they are a group beam ( 7 ) form; - devices for combining group beams ( 7 ) to a first and a second sub-beam ( 8th . 12 ), wherein the first and the second partial beam ( 8th . 12 ) are linearly polarized and have the same direction of polarization; A device for rotating the polarization direction of the second sub-beam ( 12 ) by 90 degrees; A pole cube for merging the first sub-beam ( 8th ) with the second partial beam ( 12 ) to a total jet ( 16 ). Device according to Claim 1, characterized in that all the laser diodes ( 2 ) Emit light of the same wavelength. Device according to claim 1, characterized in that the laser diodes ( 2 ) Emit light of different wavelengths. Device according to one of claims 1 to 3, characterized in that a number of laser diodes ( 2 ) are formed as laser diodes whose substrate has the elements P, In, Ga and / or Al and which generate light having a wavelength of about 652 nm to about 664 nm. Device according to one of claims 1 to 4, characterized in that a number of laser diodes ( 2 ) Generates light with a wavelength of about 654 nm to about 662 nm. Apparatus according to claim 4 or 5, characterized in that a number of the laser diodes ( 2 ) Generates light with a maximum in wavelength at about 658 nm. Device according to one of claims 1 to 6, characterized in that a number of laser diodes ( 2 ) Generates light with a wavelength of about 401 nm to about 480 nm. Apparatus according to claim 7, characterized in that a number of laser diodes ( 2 ) Generates light with a maximum in wavelength at about 445 nm. Device according to one of claims 1 to 8, characterized in that a number of laser diodes ( 2 ) Generates light with a wavelength of about 505 nm to about 555 nm. Device according to one of claims 1 to 9, characterized in that a number of laser diodes ( 2 ) Generates light with a wavelength of about 520 nm to about 544 nm. Device according to claim 9 or 10, characterized in that a number of the laser diodes ( 2 ) Generates light with a maximum in wavelength at about 532 nm. Device according to one of claims 1 to 11, characterized in that for the combination of the group beams ( 7 ) to the first and / or second partial beam ( 8th . 12 ) a mirror ( 9 ) is provided. Device according to one of claims 1 to 12, characterized in that the laser diode groups ( 3 ) a sub-device ( 17 . 18 ) are arranged offset in height to each other. Device according to one of claims 1 to 13, characterized in that for rotation of the polarization direction of the second partial beam ( 12 ) a λ / 2 plate is provided. Device according to one of claims 1 to 13, characterized in that for rotation of the polarization direction of the second partial beam ( 12 ) a mirror system ( 25 ) is provided. Device according to one of claims 1 to 15, characterized in that for the collimation of the first and second partial beam ( 8th . 12 ) and / or the total beam ( 16 ) a collimator ( 10 ) is provided. Method for producing a laser beam, comprising the following steps: - generating a plurality of individual beams ( 4 ) by a plurality of laser diodes ( 2 ); - merging the individual beams ( 4 ) of several laser diodes ( 2 ) containing a laser diode group ( 3 ), by means of deflecting mirrors ( 5 ) to a group beam ( 7 ), wherein within a laser diode group ( 3 ) the deflecting mirror (5) are arranged and aligned such that the deflected individual beams ( 6 ) of the laser diode group ( 3 ) are parallel and so close to each other, that they are a group beam ( 7 ) form; - if necessary combination of several group beams ( 7 ) to a first and a second sub-beam ( 8th . 12 ), wherein the first and the second partial beam ( 8th . 12 ) are linearly polarized and have the same direction of polarization; Turning the polarization direction of the second sub-beam ( 12 ) by 90 degrees; Merging the first sub-beam ( 8th ) with the second partial beam ( 12 ) to a total jet ( 16 ) with the help of a pole cube ( 15 ). Method according to claim 17, characterized in that all laser diodes ( 2 ) Emit light of the same wavelength. Method according to Claim 1, characterized in that the laser diodes ( 2 ) Emit light of different wavelengths. Method according to one of Claims 17 to 19, characterized in that a number of the laser diodes ( 2 ) are used as laser diodes whose substrate has the elements P, In, Ga and / or Al and which generate light having a wavelength of about 652 nm to about 664 nm. Method according to one of Claims 17 to 20, characterized in that a number of the laser diodes ( 2 ) Generates light with a wavelength of about 654 nm to about 662 nm. Method according to claim 20 or 21, characterized in that a number of the laser diodes ( 2 ) Generates light with a maximum in wavelength at about 658 nm. Method according to one of Claims 17 to 22, characterized in that a number of the laser diodes ( 2 ) Generates light with a wavelength of about 401 nm to about 480 nm. Method according to claim 23, characterized in that a number of the laser diodes ( 2 ) Generates light with a maximum in wavelength at about 445 nm. Method according to one of Claims 17 to 24, characterized in that a number of the laser diodes ( 2 ) Generates light with a wavelength of about 505 nm to about 555 nm. Method according to one of claims 17 to 25, characterized in that a number of Laser diodes generate light with a wavelength of about 520 nm to about 544 nm. Method according to claim 25 or 26, characterized in that a number of the laser diodes ( 2 ) Generates light with a maximum in wavelength at about 532 nm. Method according to one of claims 17 to 27, characterized in that for the combination of the group beams ( 7 ) to the first and / or second partial beam ( 8th . 12 ) a mirror ( 9 ) is used. Method according to one of claims 17 to 28, characterized in that the polarization direction of the second partial beam ( 12 ) is rotated with a λ / 2 plate. Method according to one of claims 17 to 29, characterized in that the polarization direction of the second partial beam ( 12 ) with a mirror system ( 25 ) is rotated. Method according to one of claims 17 to 30, characterized in that the first and second partial beam ( 8th . 12 ) and / or the total jet ( 16 ) with a collimator ( 10 ) is collimated. Use of a device ( 1 ) according to one of claims 1 to 16 for the projection of beams and / or images.