Laser diode device and method for manufacturing a laser diode device

Abstract

The present invention provides a laser diode device (10) comprising a substrate (1) with a first base element (2a), which rises as an elevation from a top side of the substrate (1) and comprises a first mounting surface (3a) for at least one first laser diode (4a), and a second base element (2b), which also rises as an elevation from the top side of the substrate (1) and comprises a second mounting surface (3b) for at least one second laser diode (4b), wherein the first base element (2a) and the second base element (2b) are separate from one another; at least one first laser diode (4a) which is arranged on the first mounting surface (3a) and at least one second laser diode (4b) which is arranged on the second mounting surface (3b);a cover cap element (5) which is placed on the upper side of the substrate (1) and fastened to the substrate (1), wherein the cover cap element (5) comprises an outer wall (6) which laterally surrounds the first base element (2a) and the second base element (2b), and wherein the cover cap element (5) covers the first base element (2a) and the second base element (2b), wherein the cover cap element (5) comprises a partition wall (TW) in its inner region (IB), which partition wall is placed on the upper side of the substrate (1) and which separates the first base element (2a) from the second base element (2b) in the inner region (IB), wherein an air access (LZ) from an outside is provided through the outer wall (6) or below the outer wall (6) to the inner region (IB) with the second base element (2b);

Description

The present invention relates to a laser diode device and a method for manufacturing a laser diode device.Prior ArtIn the production of laser diodes, these can be hermetically sealed under a nitrogen atmosphere. However, it may be more advantageous for some types of laser diodes that it may be very advantageous with regard to the lifetime, for example for a red diode, to operate them in industrial air with an oxygen content of 20% (80% nitrogen). In particular, the life of the red laser diode can be extended considerably when it is operated in an oxygen-rich atmosphere.By "industrial air" it can be understood that this can consist of 20% oxygen and 80% nitrogen and thus can have substantially the same composition as ambient air, wherein this gas mixture can however be very pure and low in particles.Disclosure of the InventionThe present invention provides a laser diode device according to claim 1 and a method of manufacturing a laser diode device according to claim 8.Preferred refinements are the subject matter of the dependent claims.Advantages of the InventionThe idea underlying the present invention is to specify a laser diode device and a method for producing a laser diode device, wherein one region of a housing can be closed by laser diodes and the other can be exposed separately therefrom to a different gas atmosphere.It is advantageously possible to provide a possibility for technical realization both for a hermetic package and for an oxygen atmosphere for the relevant diodes, and a possibility for avoiding other, expensive approaches for enclosing air.The invention advantageously makes it possible to achieve and achieve virtually or completely hermetic and / or organic-free sealing of, for example, a green and blue laser diode under nitrogen, and to achieve / achieve open (dust-proof, non-hermetic) operation of, for example, a red laser diode under ambient air.According to the invention, the laser diode device comprises a substrate having a first base element which rises as an elevation from an upper side of the substrate and comprises a first mounting surface for at least one first laser diode and a second base element which likewise rises as an elevation from the upper side of the substrate and comprises a second mounting surface for at least one second laser diode, wherein the first base element and the second base element are separated from one another; at least one first laser diode which is arranged on the first mounting surface and at least one second laser diode which is arranged on the second mounting surface; a cap member which is fitted on the top surface of the substrate and is fixed on the substrate, wherein the cap member comprises an outer wall which laterally surrounds the first base member and the second base member, and wherein the cap member covers the first base member and the second base member, wherein the cap member comprises a partition wall in the inner region thereof which is fitted on the top surface of the substrate and which in the inner region separates the first base member from the second base member, wherein an air access from an outer side is provided through the outer wall or below the outer wall to the inner region with the second base member.It may be true, for example, for a green and a blue laser diode that they may be very sensitive to organics and consequently should be operated in a hermetic package to largely keep organic contaminants away from the outside world. These diodes do not require technically oxygen in the environment and can be operated under a pure nitrogen atmosphere or industrial air.The substrate can be a coherent or multipart substrate on which the base elements can be arranged or formed.The base element may be a ceramic element. All joining materials mentioned below can be selected such that renewed melting in subsequent method steps is unlikely and these can be largely free of organic matter. The laser diodes can be mounted, for example, by curing a low outgassing silver sinter paste (e.g., comprising silver) and wire bonding. The cover cap element can have windows for emitting the diode radiation, for example with a glass window, which can have a metallization for connection to the cover cap element and can be connected, for example, to an AuSn (gold-tin) connection. A soldering mold for connecting the covering cap element to the substrate can comprise SnSb, for example, and can take place approximately in the temperature range 240 to 260° C.A red laser diode may be immune to organicity and such diodes may be open and operate without a hermetic package. These can also be used on an industrial scale, such as in a CD player, and requires an oxygen-rich atmosphere (e.g., 20% oxygen, 80% nitrogen) for stable operation over the lifetime thereof. Usually, a hermetic sealing of all three laser diodes can usually take place without organic components by means of a soldering process (soldering of the cap to the substrate), wherein flux materials should not be applied on account of the organic component. Consequently, brazing is actually possible exclusively under pure nitrogen. The hermetic, organic-free enclosure of industrial air by means of soldering is very cumbersome or possible without any measures under certain circumstances.In other words, the cover cap element and the interior space for the laser diodes (and also the base as a laser module) can be divided into two parts, wherein a nearly or completely hermetically sealed part can be present for the blue and green laser diodes and a non-hermetic part can be present for the red laser diode.According to a preferred embodiment of the laser diode device, the first laser diode is provided for operation under nitrogen and with isolation of oxygen and the second laser diode is provided for operation with ambient air.According to a preferred embodiment of the laser diode device, the partition wall and the outer wall, with the exception of the air access, are all around fixed on the upper side of the substrate with a solder.According to a preferred embodiment of the laser diode device, the air access represents an opening in the solder with a predetermined width.According to a preferred embodiment of the laser diode device, the second laser diode comprises a red laser diode.According to a preferred embodiment of the laser diode device, the first laser diode comprises a green or blue laser diode or the laser diode device comprises a third laser diode which is arranged on the first mounting surface and wherein the first laser diode comprises a green laser diode and the third laser diode comprises a blue laser diode.According to a preferred embodiment of the laser diode device, the cover cap element has in each case one emission opening for the first laser diode and / or for the second laser diode in the outer wall and / or in a cover wall.According to the invention, in the method for producing a laser diode device, a substrate is provided having a first base element which rises as an elevation from an upper side of the substrate and comprises a first mounting surface for at least one first laser diode and a second base element which likewise rises as an elevation from the upper side of the substrate and comprises a second mounting surface for at least one second laser diode, wherein the first base element and the second base element are separated from one another; arranging at least one first laser diode on the first mounting surface and arranging at least one second laser diode on the second mounting surface; arranging a cover cap element which is placed on the top side of the substrate and is fastened on the substrate, wherein the cover cap element comprises an outer wall which laterally surrounds the first base element and the second base element, and wherein the cover cap element covers the first base element and the second base element, wherein the cover cap element comprises a dividing wall in the inner region thereof, which dividing wall is placed on the top side of the substrate and which separates the first base element from the second base element in the inner region, wherein an air access from an outer side is introduced through the outer wall or below the outer wall to the inner region with the second base element.According to a preferred embodiment of the method, a nitrogen atmosphere is provided and the cover cap element is placed on the upper side of the substrate and soldered to the substrate under the nitrogen atmosphere.According to a preferred embodiment of the method, a solder mask is used which has a recess for the air access and, after the soldering process, the air access remains as a recess in the solder and between the substrate and the outer wall.According to a preferred embodiment of the method, a predetermined amount of industrial air is introduced into the interior region with the second base element through the air inlet. Gas exchange with the ambient air during the lifetime is not disadvantageous since-as already mentioned above-red laser diodes can be operated under normal ambient air (for example in a CD player).The method can also be distinguished by the features and advantages already mentioned in the context of the laser device, and vice versa.The present invention describes a cost-effective method (and structure) with which the first laser diode can be hermetically packaged without organic components in a nitrogen atmosphere and at the same time the operation of the second laser diode is made possible in a dust-proof manner under ambient air-in particular in an oxygen-containing atmosphere.Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the attached drawings.Brief Description of the DrawingsThe present invention is explained in more detail below with reference to the exemplary embodiments indicated in the schematic figures of the drawing.The following are shown: FIG. 1 shows a schematic sectional illustration of a laser diode device according to an exemplary embodiment of the present invention in a lateral section and in a horizontal section and a comparison with a known laser diode device; FIG. 2 shows a block diagram of method steps of the method for producing a laser diode device according to an exemplary embodiment of the present invention.In the figures, identical reference numerals designate identical or functionally identical elements.FIG. 1 shows a schematic sectional illustration of a laser diode device according to an exemplary embodiment of the present invention in a lateral section and in a horizontal section and a comparison with a known laser diode device.The left-hand representations of FIG. a show a lateral section (upper image) and a horizontal section (lower image) of an already known embodiment.The right hand representations of Figure b show a lateral section (top image) and a horizontal section (bottom image) of an embodiment of the present invention.According to the left-hand embodiment, all three laser diodes 4 are arranged within a cap 5 and on a base 2 and under the same atmosphere. The lower image shows the radiation through a lateral window.According to the right-hand embodiment of the invention, a substrate 1 is present, having a first base element 2 awhich rises as a protrusion from a top side of the substrate 1 and comprises a first mounting surface 3 afor at least one first laser diode 4 aand a second base element 2 bwhich likewise rises as a protrusion from the top side of the substrate 1 and comprises a second mounting surface 3 bfor at least one second laser diode 4 b, wherein the first base element 2 aand the second base element 2 bare separated from one another. Furthermore, a first laser diode 4 ais present, which is arranged on the first mounting surface 3 aand at least one second laser diode 4 bis present, which is arranged on the second mounting surface 3 b. Furthermore, a cover cap element 5 is present, which is placed on the upper side of the substrate 1 and is fastened on the substrate 1, wherein the cover cap element 5 comprises an outer wall 6, which laterally surrounds the first base element 2 aand the second base element 2 b, and wherein the cover cap element 5 covers the first base element 2 aand the second base element 2 b, wherein the cover cap element 5 comprises a separating wall TW in its inner region IB, which is placed on the upper side of the substrate 1 and which separates the first base element 2 afrom the second base element 2 bin the inner region IB, wherein an air access LZ from an outer side is present through the outer wall 6 or below the outer wall 6 to the inner region IB with the second base element 2 b.The partition wall TW and the outer wall 6, with the exception of the air access LZ, can advantageously be fixed all around on the top side of the substrate 1 with a solder, wherein the air access can represent an opening in the solder with a predetermined width. The second laser diode 4 bmay advantageously comprise a red laser diode. In this case, the first laser diode 4 acan comprise a green laser diode and a third laser diode 4 con the first mounting surface 3 acan comprise a blue laser diode. Furthermore, the cover cap element 5 can have in each case one emission opening AO for the first laser diode 4 aand for the second laser diode 4 band for the third laser diode 4 cin the outer wall 6 and / or in a cover wall 7. The partial region of the inner region IB, which comprises and covers the first base element 2 a, can remain with a nitrogen atmosphere (maximum 1000 ppm oxygen) resulting from the soldering process and largely free of organic matter, whereas the further partial region of the inner region IB with the second base element can be actively exposed to an air atmosphere through the air access after the soldering. The second laser diode 4 bmay be contacted to the substrate 1 by one or more bonding wires DB, advantageously within the inner region IB.In other words, the cover cap element 5 can be designed accordingly and comprise the partition wall TW as an additional wall as a boundary between the hermetic (~1*10 -8 mbar l / s) and the non-hermetic part. The covering cap element can be closed almost without organic means by means of soldering and the soldering can take place under nitrogen. Oxidation of the solder can thus be ruled out or the probability thereof can be reduced, whereby consistent wetting can be ensured. The solder preform ("solder") can be designed such that it can have a small slot (air access LZ) in the non-hermetic region. This slot can be designed such that it does not flow in during soldering. Consequently, a small slit may be left open in the non-hermetic portion. The red laser diode can thus still be protected against dust, but is no longer located in a hermetic region and ambient air can enter this region, which can bring the required oxygen with it. The platform (island / base element) on which the laser diodes are positioned elevated can be shortened somewhat in width and then only has the width required for the green and blue laser diodes. For the red laser diode, a separate small island may be placed before setting the laser diode to place the red laser diode at the same height. The laser diode device 10 can be formed as a laser module, wherein operation of all three laser diodes can be made possible without or with little degradation over the service life.FIG. 2 shows a block diagram of method steps of the method for producing a laser diode device according to an exemplary embodiment of the present invention.In the method for producing a laser diode device, a substrate is provided S 1 having a first base element which rises as a protrusion from a top side of the substrate and comprises a first mounting surface for at least one first laser diode and a second base element which likewise rises as a protrusion from the top side of the substrate and comprises a second mounting surface for at least one second laser diode, wherein the first base element and the second base element are separated from one another; arranging S 2 at least one first laser diode on the first mounting surface and arranging S 3 at least one second laser diode on the second mounting surface; arranging S 4 a cover cap element which is placed on the upper side of the substrate and is fastened on the substrate, wherein the cover cap element comprises an outer wall which laterally surrounds the first base element and the second base element, and wherein the cover cap element covers the first base element and the second base element, wherein the cover cap element comprises a dividing wall in the inner region thereof, which dividing wall is placed on the upper side of the substrate and which in the inner region separates the first base element from the second base element, wherein an air access from an outer side is introduced through the outer wall or below the outer wall to the inner region.Although the present invention has been fully described above with reference to preferred exemplary embodiments, it is not restricted thereto, but can be modified in a variety of ways.

Claims

Laser diode device (10) comprising - a substrate (1) having a first base element (2a) which rises as a protrusion from a top side of the substrate (1) and comprises a first mounting surface (3a) for at least one first laser diode (4a) and a second base element (2b) which likewise rises as a protrusion from the top side of the substrate (1) and comprises a second mounting surface (3b) for at least one second laser diode (4b), wherein the first base element (2a) and the second base element (2b) are separated from one another; - at least one first laser diode (4a) which is arranged on the first mounting surface (3a) and at least one second laser diode (4b) which is arranged on the second mounting surface (3b); - a cover cap element (5), which is placed on the top side of the substrate (1) and is fastened on the substrate (1), wherein the covering cap element (5) comprises an outer wall (6) which laterally surrounds the first base element (2a) and the second base element (2b), and wherein the covering cap element (5) covers the first base element (2a) and the second base element (2b), wherein the covering cap element (5) comprises a dividing wall (TW) in its inner region (IB), which is placed on the top side of the substrate (1) and which separates the first base element (2a) from the second base element (2b) in the inner region (IB), wherein an air access (LZ) from an outer side is provided through the outer wall (6) or below the outer wall (6) to the inner region (IB) with the second base element (2b).A laser diode device (10) as claimed in claim 1, wherein the first laser diode (4a) is for operation under nitrogen and with isolation of oxygen and the second laser diode (4b) is for operation with ambient air.The laser diode device (10) according to claim 1 or 2, wherein the partition wall (TW) and the outer wall (6) except for the air access (LZ) are all fixed with a solder on the upper surface of the substrate (1).The laser diode device (10) of claim 3, wherein the air port provides an opening in the solder having a predetermined width.Laser diode device (10) according to one of claims 1 to 4, wherein the second laser diode (4b) comprises a red laser diode.Laser diode device (10) according to one of claims 1 to 5, wherein the first laser diode (4a) comprises a green or blue laser diode or the laser diode device (10) comprises a third laser diode (4c) which is arranged on the first mounting surface (3a) and wherein the first laser diode (4a) comprises a green laser diode and the third laser diode (4c) comprises a blue laser diode.Laser diode device (10) according to one of Claims 1 to 6, in which the covering cap element (5) has in each case one emission opening (AO) for the first laser diode (4a) and / or for the second laser diode (4b) in the outer wall (6) and / or in a cover wall (7).Method for producing a laser diode device (10), comprising the steps of: - providing (S1) a substrate (1) having a first base element (2a) which rises as a protrusion from a top side of the substrate (1) and comprises a first mounting surface (3a) for at least one first laser diode (4a), and a second base element (2b) which likewise rises as a protrusion from the top side of the substrate (1) and comprises a second mounting surface (3b) for at least one second laser diode (4b), wherein the first base element (2a) and the second base element (2b) are separated from one another; - arranging (S2) at least one first laser diode (4a) on the first mounting surface (3a) and arranging (S3) at least one second laser diode (4b) on the second mounting surface (3b); arranging (S4) a cover cap element (5) which is placed on the top side of the substrate (1) and is fastened on the substrate (1), wherein the cover cap element (5) comprises an outer wall (6) which laterally surrounds the first base element (2a) and the second base element (2b), and wherein the cover cap element (5) covers the first base element (2a) and the second base element (2b), wherein the cover cap element (5) comprises a separating wall (TW) in its inner region (IB), which separating wall is placed on the top side of the substrate (1) and which separating the first base element (2a) from the second base element (2b) in the inner region (IB), wherein an air access (LZ) is introduced from an outer side through the outer wall (6) or below the outer wall (6) to the inner region (IB) with the second base element (2b).Method according to claim 8, in which a nitrogen atmosphere is provided and the covering cap element (5) is placed on the upper side of the substrate (1) and soldered to the substrate under the nitrogen atmosphere.Method according to claim 9, wherein a solder mask is used which has a recess for the air access (LZ) and, after the soldering operation, the air access (LZ) remains as a recess in the solder and between the substrate (1) and the outer wall (6).Method according to claim 10, wherein a predetermined amount of industrial air is introduced into the interior region (IB) with the second base element (2b) through the air access (LZ).

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