DE10254566B4 - Laser diode arrangement with bridging units - Google Patents

Abstract

Laser diode arrangement having a plurality of laser bars (3) connected in series, one laser bar (3) each having a plurality of diodes or emitters and each laser bar (3) being assigned a bridging unit (7, 7d) which then bridges the laser bar (3) assigned to it when the voltage applied to this laser carcass (3) exceeds a predetermined threshold value (U _Ref ) at which each laser bar (3) together with the associated bridging unit (7, 7d) is provided on a common support (2) formed as a heat sink, and in which the carriers (2) are arranged stacked next to one another in such a way that the bridging units (7, 7d) are provided between the carriers (2) adjoining each other in a stack, characterized in that the bridging units (7, 7d) are considered to be clean electromechanical units are formed, by means of which the defective laser bar (3) is permanently bridged.

Description

The The invention relates to a laser diode arrangement according to the preamble Claim 1.

The laser diode of this kind are known and usually consist of several, each on a heat sink provided laser bars, which in turn a variety of laser devices or diodes, for example, up to 200 such devices. The provided with the laser bar heat sinks are stacked (stack or laser diode stack), wherein such a Stack, for example, four or more than four such heat sinks having laser bars.

The Arrangement is made such that the laser bars with the planes their active layers are arranged parallel to each other. By a corresponding optics are the individual beams of the laser diodes summarized to a total beam.

The individual laser devices or diodes are in each laser bar provided parallel to each other between two outer terminals, with those of the laser bars on the one hand to an electrically conductive surface of a Side of the heat sink, for example by soldering contacted and on the other hand with a relation to the heat sink insulated contact element connected is. The operating voltage of such laser bars (hereinafter also more generally referred to as a laser diode group) is on the order of magnitude from about 1.6 to 1.8 volts, but may age with the laser bar also increase a bit.

Out establish a simplification of the power and voltage supply are the Laser bar in the respective laser diode assembly electrically in Provided series connected, between the outer electrical connections this arrangement.

Especially in direct diode lasers with high power, for example with a power of a few kW, are several such laser diode arrays or stacks present, the laser beams of these arrangements then combined by an appropriate optics to a total laser beam become.

One Disadvantage of this technique is that it can be damaged by aging or also overload to failures first single laser diodes of a laser bar and then finally too to the failure of the entire laser bar of a laser diode array can come. This means in the series connection of the laser bars in the relevant laser diode arrangement, the latter being complete fails.

adversely is also that, for example, in an aging-related increase the operating voltage of a laser bar, the supply voltage for the relevant Diode laser arrangement u. U. increased must be to make a change the power and / or the spectrum of the laser light in the other laser bars to avoid the laser diode arrangement. Even such a voltage control can be expensive, especially if a diode laser several Having laser diode arrays or Staks.

Failures of Laser diodes of a laser bar or of the whole laser bar can appear very suddenly and are not or rarely predictable. You are u. a. conditioned due to severe local damage in the respective laser bar or by mechanical "detachment" of connections z. On the p or n side of the active layer. Especially too such a detachment process can increase like an avalanche and finally lead to a complete failure of the entire laser bar, because the effective cross section for reduces the current with increasing "peeling" and thereby the power loss caused by the current flow increasingly concentrated becomes. Practice has shown that, for example, a local failure of emitters in a laser bar within a period of 10 to 100 hours to such a severe damage to the laser bar leads that finally through the occurring local overcurrents a burnup the laser bar or the laser chip and thus the complete failure this laser chip done.

It although it is possible In the case of a defective laser bar, the entire laser bar has these Disable laser diode array (stack). But this leads then to a significant power loss of a diode laser. It's this one Diode lasers, for example, 80 laser devices or diodes in eight Laser diode arrays, so are in case of a defect of a laser bar in a laser diode arrangement a total of ten components switched off, d. H. There is a power reduction of 12.5%.

A laser diode arrangement ( GB 2 278 717 A ), in which a plurality of laser diodes are operated in series with a common power source. Parallel to each laser diode, a shutdown or bridging unit is provided which shorts or shunts the respective laser diode in the event of a defect so that the laser diode arrangement can continue to be operated. The switching criterion used here is the light emitted by the respective laser diode, ie in the absence of this laser light, the short-circuiting of the be meeting the laser diode. The disadvantage here is not only a relatively large circuit complexity for the respective Abschalt- and bridging unit, but in particular, that the respective unit must be arranged with a light detector in the light path of the associated laser diode, which in particular the freedom of design of a laser diode array is severely limited.

A series arrangement of light-emitting diodes ( JP 59103565 A , Abstract) in which the individual diodes each control a photothyristor via optical fibers.

Everyone light emitting diode is another diode connected in parallel via the in the case of a defect of a light-emitting diode, the current flow through the series connection is maintained.

Also known is a laser diode arrangement which consists of several successive heat sinks and one laser bar at each heat sink ( WO 00/59086 A1 ).

It is also known ( US 2002/0150139 A1 to monitor in series and operated with a constant current source laser diodes by measuring the voltage applied to these diodes voltage on a possible malfunction out.

From the DE 102 09 374 A1 is a diode laser array having a plurality of electrically connected in series diode lasers, each containing a arranged on a cooling and contact element diode laser bars, and each of which a bypass arrangement is electrically connected in parallel. The bypass arrangement is high-impedance during normal operation and bridges the diode laser connected in parallel in the event of a high-impedance defect of the diode laser. For this purpose, the bypass arrangement is arranged on the cooling and contact element of the diode laser connected in parallel thereto. The bypass arrangement switches in particular when the voltage across the diode laser exceeds a threshold value.

task The invention is to show a laser diode array, the avoids these disadvantages and in particular also with age-related precipitate individual laser bars continue operation of a diode laser with only imperceptibly reduced power allows.

to solution This object is a laser diode arrangement according to the patent claim 1 educated. The invention will be described below with reference to FIGS to various embodiments explained in more detail. It demonstrate:

1 in a simplified representation and in side view and partially cut a laser diode assembly (laser stack) consisting of several stacked superposed and adjoining heat sinks each having at least one laser bar and a Laserbarrenabschalt- or bridging unit with a bridging element formed by an electro-mechanical contact;

2 a representation like 1 in a modified embodiment;

3 a representation like 2 but in another possible embodiment with a laser bar shutdown or bridging unit having an uncontrolled semiconductor device or circuit as a bridging element;

4 the voltage-current characteristic of the respective bridging element of the Laserbarrenabschalt- or bridging unit of 3 ;

5 in various positions a-c possible designs for the bridging element in the execution of 3 ;

6 similar in a presentation 1 a further possible embodiment with Laserbarrenabschalt- or bridging units, each with a controlled by an electronic control switching element;

7 a circuit for the control electronics and the switching element of 6 ;

8th similar in a presentation 1 another possible embodiment with each provided on an additional substrate Laserbarrenabschalt- or bridging units;

9 in side view and in disassembled state, the substrate with the laser bar shutdown and bridging unit together with the associated carrier.

In the 1 is with 1 In general, a laser diode arrangement is referred to, inter alia, of a plurality of stacked superimposed, by a cooling medium, for example, flowed through water and formed as a rectangular plates or blocks heat sinks 2 consists. At the top 2.1 and along a peripheral side 2.2 For example, a narrower peripheral side is on each heat sink 2 for example, by soldering at least one laser bar 3 of semiconductor material (eg semiconductor chip), which with its longitudinal extension perpendicular to the plane of the drawing 1 is located on the longitudinal direction in the direction of this longitudinal extension and spaced apart a plurality of laser devices or diodes ge are formed, for example, up to 200 laser devices or diodes. All laser diodes of the laser bar are provided electrically parallel to each other, between two contacts or terminals of the laser bar 3 , with this one hand, with the top of his heat sink 2 connected and on the other hand in the for the 1 selected representation above with a tongue-like contact element 4 , This is by means of an insulator 5 opposite to the existing of the electrically conductive material, such as copper heat sink 2 isolated and extends from the laser bar 3 towards the peripheral side opposite this laser bar 2.3 the heat sink 2 ,

Inside the stack is the contact tongue 4 especially where it comes from the insulator 5 is supported, with their top against the bottom 2.4 the overlying heat sink 2 at. The top contact tongue in the stack 4 and the underside of the bottom heat sink in the stack 2 are each about external contact elements 6 and associated connection lines 6.1 connected to a DC voltage or current source for the supply voltage U1, so that the laser bars 3 with respect to this supply voltage or the corresponding supply current in series between the outer terminals 6 are provided.

When in the 1 illustrated embodiment are a total of four laser bars 3 intended. Also deviating designs with more than four, z. For example, ten laser bars 3 or with less than four laser bars 3 are conceivable. Furthermore, a direct diode laser and in particular a laser with high power, in which the laser diode of the laser bars 3 generated laser light is used directly, several such laser diode arrays 1 or stacks whose laser beams are then combined in a suitable optical system to form a common output beam.

In particular by aging or else by overload, individual laser diodes or components of a laser bar 3 fail, so that continues to over this laser bar 3 flowing current concentrated on a reduced number of laser diodes, which may then fail due to overload also, and so it to an avalanche-like destruction of all laser diodes on a laser bar 3 comes, this completely fails and thus the flow of current through the remaining, still intact laser bars 3 is interrupted. This leads to failure of an entire stack or the entire laser diode arrangement in the case of a high-power diode laser and, in the case of several such stacks, to a corresponding loss of power.

To avoid this or in case of failure of a laser bar 3 the current flow through the remaining, undamaged laser bars 3 is fully maintained in the 1 illustrated laser diode arrangement for each laser bar 3 a separate general with 7 designated laser bar bridging unit provided on the top 2.1 the heat sink 2 of the laser bar 3 provided and formed in this embodiment as a purely electromechanical unit.

The operation of the bridging unit 7 based on the fact that in case of failure of a laser bar 3 the voltage applied to this bar then voltage U1 corresponds, that is much higher than the normal operating voltage of 1.6 to 1.8 volts of a properly operating laser bar 3 , By this in case of failure of the laser bar 3 detectable voltage increase at the terminals of the laser bar 3 or between the heat sink 2 and the associated contact tongue 4 becomes the laser bar bridging unit 7 for bridging or short-circuiting the defective laser bar 3 activated and triggered.

For this purpose, the laser bar bridging unit 7 a heating element 8th which is electrically parallel to the associated laser bar 3 lies and for this over a connection 9 directly with the associated heat sink 2 and also with the resilient contact forming end 4.1 the contact tongue 4 is connected, via a melting body in the form of a platelet 10 from an electrically conductive, but melting on exposure to heat, for example, a solder.

Due to the support on the plate 10 is the contact spring 4.1 or a contact area generated by bending on this contact spring 4.2 from the electrically conductive surface of the associated heat sink 2 spaced. The heating element 8th and the material for the slide 10 are selected so that the normal operating voltage of a laser bar 3 not for warming or significant heating of the plate 10 sufficient. But as soon as a laser bar 3 fails and thereby on the heating element 8th the associated bridging element 7 the higher voltage U1 is applied, there is a heating of the platelet 10 through the heating element 8th in such a way that this platelet melts and the contact spring 4.1 with her contact area 4.2 against the conductive surface of the heat sink 2 comes to the plant, bringing the broken laser bar 3 permanently through the contact spring 4.1 is bridged.

The 2 shows as a modification of 1 a laser diode arrangement 1a that differ from the laser diode arrangement 1 and their function differs essentially only in that each La serbarrenüberbrückungselement 7a which in turn is for every laser bar 3 is provided separately, a heating element 8th controlling control electronics 11 having. This control electronics 11 Measures during operation of the laser diode array 1a at the associated laser bar 3 voltage applied. If the measured voltage exceeds a limiting voltage lying above the usual operating voltage, for example a limiting voltage of 2 to 3 volts, the control electronics are used 11 the heating element 8th for heating and melting the respective fusible or platelet 10 activated, which in turn via the contact spring 4.1 and the contact 4.2 electromechanically the respective laser bar 3 short-circuited or bridged. The laser bar bridging unit 7a It also allows aging-induced voltage increases on a laser bar 3 to capture and use as a shutdown criterion, ie the corresponding laser bar 3 to switch off already at an age-related increase in its operating voltage before a final failure of all components or laser diodes of this laser bar enters. In this way, in particular, it is also avoided that due to an aging-induced increase in voltage at a laser bar, the remaining voltage drops across the remaining laser bars and therefore no longer deliver the desired power and / or the desired laser light spectrum.

An essential advantage of the laser bar bridging unit 7 and 7a is that after activation of the respective bridging unit of the respective laser bar 3 permanently bridged, without that after bridging in the laser bar bridging unit 7 respectively. 7a a power loss arises.

The 3 shows as a further possible embodiment, a laser diode assembly 1b in which the for each laser bar 3 separately provided laser bar bridging units 7b is formed by a non-controlled electronic component or by a combination of such components.

The operation of the laser diode array 1b or their bridging units 7b is that in case of failure of a laser bar 3 or with an increase in the voltage across a laser bar 3 over a predetermined threshold or threshold voltage, for example, a voltage greater than 2 to 3 volts, the current flow over the respective laser bar 3 associated laser bar bridging unit 7b he follows. For this purpose, this laser bar bridging unit or its bridging element in the 4 represented voltage-current characteristic in which the current flowing through the laser bar bridging element current I up to the voltage limit U _{K is} practically negligible and only from the voltage U _K, a current flow is possible to a considerable extent.

In the 5 are shown in the positions a-c different possibilities for the formation of the laser bar bridging element. Corresponding to the position a, the laser bar bridging element is, for example, a mosfet 12 formed with a bridge between the drain and gate, wherein for the threshold voltage U _K results in a voltage value between about 3 and 5 volts. Corresponding to the position b, there is the bridging element of the laser bar bridging unit 7b from a zener diode 13 , Wherein the Zener voltage and thus the threshold voltage U _{K can be set} in this embodiment by appropriate doping of the semiconductor material to a value which is very close to the usual operating voltage of the laser bar 3 lies.

The position 3c shows the combination 14 two silicon diodes parallel to the respective laser bar 3 lie where then a threshold voltage U _K results, which corresponds to twice the threshold voltage in silicon diodes, for example in the range between 1.6 to 2.2 volts. If a lower limit voltage is desired, then a series connection of a silicon Schottky diode with a silicon diode with PN junction or the series connection of a silicon diode and a germanium diode is conceivable.

The laser bar bridging unit 7b has the advantage of a simple and robust design, but also the disadvantage that after switching off a laser bar 3 a significant voltage then at the laser bar bridging element 7b is applied, taking into account by the laser diode array 1b flowing current means a significant power loss, which on the relevant heat sink 2 must be removed.

The 6 shows in a presentation like 1 as a further embodiment, a laser diode arrangement 1c with laser bar bridging units 7c , of which in turn each a laser bar 3 assigned and at the top 2.1 the heat sink 2 this laser bar is provided.

Each laser bar bypass unit 7c consists of an electronic control system 16 and from a controlled by this control electronics switching element 17 , which in the switched or activated state, the bridging of the associated laser bar 3 causes. The switching element 17 lies for this purpose with its switching path between the contact tongue 4 corresponding contact tongue 4c and the conductive surface of the respective heat sink 2 , For the individual laser bar bridging units 7c is at the in the 6 illustrated embodiment, a separate power supply source provided, which supplies the DC supply voltage U2. This supply voltage U2 is slightly larger than the supply voltage U1 for the series connection of the laser bars 3 , in fact U2 = U1 + U X . where U _{X is} the voltage that the respective laser bar bridging unit 7c or their control electronics 16 and switching element 17 for the way of working. The voltage U _X is for example in the range between 10 and 15 volts.

The general operation of each control electronics 16 corresponds to the operation of the control electronics 11 ie the control electronics 16 compares those at the associated laser bar 3 or between the reed 4c and the heat sink 2 applied voltage with a threshold value or a reference voltage U _Ref . Exceeds that on the laser bar 3 voltage applied to the threshold, then the switching element 17 controlled such that it the respective laser bars 3 bridged.

The 7 shows the circuit of a possible embodiment of the laser bar bridging unit 7c , The switching element 17 is formed in this embodiment by a power transistor T2 (Mosfet), which is locked in the normal operating state and with its drain-source path parallel to the respective laser bar 3 or parallel to the terminals LD (+) and LD (-) of the Laerbarrens is located.

The control electronics 16 includes, inter alia, one of the transistor T1, the resistor R1, the zener diode D1 and the capacitor C1 formed voltage regulation. Furthermore, the control electronics comprises a comparator CP to which the voltage applied between the terminals LD (+) and LD (-) and the reference voltage U _Ref formed by the voltage divider consisting of the resistor R2 and the zener diode D2 are supplied. The output of the comparator CP controls a memory element FF whose output drives the gate of the transistor T2 via a voltage or emitter follower formed by the two transistors T3 and T4.

For the control electronics 16 are power-saving components used, so that the power consumption in the μA range and also the power loss at the voltage regulator transistor T1 is low. Currents needed for fast switching operations can be taken from capacitor C1.

Parallel to the gate and drain of the transistor T2, a diode D3 is arranged, which accelerates the switching of the transistor T2 into the conducting state, namely, when the voltage between the terminals LD (+) and LD (-) exceeds the threshold.

The way of working in the 7 shown embodiment of the laser bar bridging unit 7c results from this representation, ie in the normal state is at the output of the comparator CP and thus also at the output of the memory FF, the voltage value zero, so that the transistor T2 is blocked. Increase in case of laser barring failure 3 the voltage above the threshold U _Ref , then go the outputs of the comparator and the memory FF in the high state and the transistor T2 in the conductive state, bringing the corresponding laser bar 3 is bridged or shorted. In order to maintain this state, the memory element FF is, for example, a non-volatile memory, for example an EE-PROM or a microprocessor with an EE-PROM.

Basically, there is the described embodiment of the laser bar bridging element 7c also the possibility of the supply voltage for the control electronics 16 and the switching element 17 in each case by DC / DC conversion from the laser diode bar 3 to generate applied voltage. The advantage of this solution would be that it is possible to dispense with the external additional supply voltage U2. A problem, however, is that bridged by the transistor T2 (Mosfet) laser bar 3 the then applied voltage is very small and also dependent on the current (for example of the order of 0.5 volts). In this case, it is then expedient, before the actual commissioning of the laser diode array 1c to apply these with a small current.

It would also be advantageous in this embodiment, as a switching element to use a normally conducting MOSFET (depletion MOSFET), as this is already in a conducting state at zero gate voltage and thereby the problem of missing or too low supply voltage at bridged laser diode bar 3 is defused.

The 8th and 9 show as a further possible embodiment, a laser diode arrangement 1d that differ from the laser diode arrangement 1c essentially differs in that the laser bar bridging unit 7d or the elements forming this bridging unit, namely the control electronics 16 and the switching element 17 at the bottom of an additional flat, plate-shaped carrier or substrate 18 (Contact carrier) are arranged. The switching element 17 is with a contact spring 19 Mistake. In the assembled state is (except the topmost substrate 18 ) the respective substrate 18 in the heat sinks 2 formed stack with a portion between the top of one of the contact tongue 4c corresponding contact tongue 4d and the bottom 2.4 an adjacent heat sink 2 arranged and held by clamping or in any other suitable manner. The topmost substrate 18 is between in the 8th not shown outer terminal contact 6 and the adjacent contact tongue 4d held. The contact spring 19 lies resiliently against the top 1.2 the electrically conductive heat sink 2 and thereby makes contact without soldering or bonding between the switching element 17 and the heat sink and connected to this heat sink terminal of the laser bar 3 ago.

The substrate 18 For example, it consists of a layer of an insulating material, which is provided on both sides with a metal layer. By a corresponding structuring and via is achieved that on the substrate 18 on the one hand, an electrical connection between the switching element 17 and the associated contact tongue 4d on the other hand, over the substrate 18 also an electrical connection between each contact tongue 4d and the adjacent heat sink 2 or the adjacent outer terminal contact 6 is made.

As shown, the substrate stands 18 with a subarea 18.1 over the laser bar 3 opposite side 2.3 the relevant heat sink 2 path. At this subarea 18.1 are the control electronics 16 and the switching element 17 provided so that the height of the heat sink 2 as a space for the accommodation of these elements can be used. The control electronics 16 the laser bar bridging units 7d For example, in connection with the 6 described manner supplied with the DC supply voltage U2. Also another, related to the 6 described supply of the respective control electronics 16 z. B. by DC / DC conversion of the laser diode bar 3 voltage applied, etc. is possible.

Furthermore, it is possible in the execution of 8th instead of the control electronics 16 and the controllable switching element, which z. As a transistor, Mosfet, thyristor, etc., an electromechanical switching or bridging element is provided, for example, one of the contact spring 4.1 corresponding resilient contact together with a heating element 8th and a fusible spacer 10 ,

The The invention has been described above in various embodiments described. It is understood that numerous other modifications and Modifications possible are, without thereby the The invention underlying the invention is abandoned. For example, it is possible a laser bar bridging unit or its bridging element to integrate in the laser bars, and in particular even if this bridging unit or its bridging element is formed by one or more semiconductor devices and / or of structures made in semiconductor technology can.

Furthermore, there is also the possibility of the individual laser bar bridging units 7 - 7c For example, to connect to a data or control bus over which then the state of each laser bar or laser diode arrays (stacks) of a laser can be displayed and / or read. Furthermore, such a data or control bus could also be used to selectively shut down individual laser bars 3 from outside to initiate or initiate.

In the described embodiments, in particular the 1 . 2 and 6 Furthermore, it is also possible, via the voltage applied to the series connection of the laser bar voltage, the number of defective and disconnected laser bars 3 to investigate.

1, 1a, 1b, 1c, 1d

The laser diode

2

heat sink

2.1

top

2.2 2.3

peripheral side

2.4

bottom

3

laser bars

4, 4b, 4c

contact tongue

4.1

contact spring

4.2

contact area

5

insulator

6

connection contact

6.1

lead

7, 7a, 7b, 7c, 7d

Laser bar bridging unit

8th

heating element

9

Connection

10

spacer made of electrically conductive but meltable material

11

control electronics

12

Mosfet

13

Zener diode

14

diode array

16

control electronics

17

switching element

18

substratum

18.1

section

19

contact spring

Claims (14)

Laser diode arrangement with a plurality of laser bars connected in series ( 3 ), whereby a laser bar ( 3 ) each have a plurality of diodes or emitters and each laser bar ( 3 ) a bridging unit ( 7 . 7d ) associated with the laser bar associated therewith ( 3 ) then bridged when the on this laser car ( 3 ) voltage exceeds a predetermined threshold (U _Ref ) at which each laser bar ( 3 ) together with the associated bridging unit ( 7 . 7d ) on a common heat sink formed carrier ( 2 ) and where the carriers ( 2 ) are arranged next to one another in a stack, in such a way that the bridging units ( 7 . 7d ) between the stack-like carriers ( 2 ), characterized in that the bridging units ( 7 . 7d ) are formed as purely electromechanical units, by means of which the defective laser bar ( 3 ) is permanently bridged. Laser diode arrangement according to Claim 1, characterized in that the supports ( 2 ) are each at least partially made of an electrically conductive material, for example of metal and thereby by each support ( 2 ) through an electrical connection between an electrically conductive region on a first carrier side ( 2.1 ), with a first connection of its laser bar ( 3 ), and an electrically conductive region of a second, opposite carrier side ( 2.4 ) is that on the first carrier side ( 2.1 ) electrically isolated a contact element ( 4 ) for contacting a second terminal of the laser bar ( 3 ) and that the beams ( 2 ) in which the laser diode array forming stack are arranged such that, with the exception of the bottom carrier ( 2 ) each carrier for electrical connection to the electrically conductive region of its second carrier side ( 2.4 ) against the contact element ( 4 . 4d ) of an adjacent carrier ( 2 ) is present. Laser diode arrangement according to Claim 2, characterized in that the contact elements have contact tongues ( 4 ) are, Laser diode arrangement according to one of the preceding claims, characterized in that the bridging unit ( 7 . 7d ) a bridging element ( 4.1 . 17 ), which parallel to the associated laser bar ( 3 ) lies. Laser diode arrangement according to one of the preceding claims, characterized in that the respective bridging unit ( 7d ) on one with the carrier ( 2 ) at least mechanically connected substrate ( 18 ) is provided. Laser diode arrangement according to claim 5, characterized in that the substrate ( 18 ) on the side ( 2.1 ) of the carrier, on which also the at least one laser bar ( 3 ) is provided. Laser diode arrangement according to claim 5 or 6, characterized in that the substrate ( 18 ) at least partially over the at least one laser bar ( 3 ) remote page ( 2.3 ) of the carrier. Laser diode arrangement according to one of the preceding claims, characterized by control electronics ( 11 . 16 ), which determines the operating voltage at the respective laser bar ( 3 ) and compared with the threshold value (U _Ref ) and, when the threshold value (U _Ref ) is exceeded, a signal for activating the bridging unit (FIG. 7 . 7d ) or the bridging element ( 4.1 . 17 ). Laser diode arrangement according to one of claims 4 to 8, characterized in that the bridging element is a mechanical contact ( 4.1 ), and that control means ( 8th . 10 ) are provided to the mechanical contact ( 4.1 ) when the threshold value (U _Ref ) is exceeded from a normally open state into an associated laser bar ( 3 ) Bridging to bring. Laser diode arrangement according to claim 9, characterized in that the mechanical contact ( 4.1 ) is resiliently biased in the closed position and that the means for triggering or controlling the contact of a melting body ( 10 ) as well as a heating element heating this melting body ( 8th ) are formed. Laser diode arrangement according to claim 10, characterized in that the melting body ( 10 ) a mechanical contact ( 4.1 ) is in the open position holding spacer. Laser diode arrangement according to claim 10 or 11, characterized in that the opened contact ( 4.1 ) and the heating element ( 8th ) one parallel to the associated laser bar ( 3 ) form a series circuit. Laser diode arrangement according to one of Claims 10 to 12, characterized in that the heating element ( 8th ) by the control electronics ( 11 ) is driven. Laser diode arrangement according to one of Claims 9 to 13, characterized in that the mechanical contact ( 4.1 ) of the bridging element of a partial length of a contact tongue ( 4 ) is formed, which is also the contact element to the Kon clocking the respective laser bars ( 3 ).