WO2025012379A1 - Laser package, laser device and method for the production thereof - Google Patents

Abstract

The invention relates to a laser package comprising: a base element, which has an arrangement surface on which at least one semiconductor laser element is arranged; a cover element, which is transparent to the laser light emitted from the at least one semiconductor laser element, is connected to the base element, forms a frame that surrounds the at least one semiconductor laser element in a lateral direction, and encapsulates the at least one semiconductor laser element with the base element; an optical element, which is located on the cover element; and at least one deflection element, which is located in the beam path of the at least one semiconductor laser element and is designed to deflect a laser light emitted from the at least one semiconductor laser element in the direction of the at least one optical element. The optical element is fastened to the cover element by means of a connecting material, wherein the connecting material comprises a proportion of at least 30% of silicon and a light-hardening component. In addition, the connecting material is light-activatable and can be hardened at least in part by means of light hardening.

Description

LASER PACKAGE, LASER DEVICE AND METHOD FOR MANUFACTURING

The present application claims the priority of German patent application No . 10 2023 118 459 . 8 of July 12, 2023, the disclosure content of which is hereby incorporated into the present application by reference.

The present invention relates to a laser package and a laser device comprising at least two laser packages, as well as a method for producing a laser package.

BACKGROUND

An encapsulated laser package with deflection mirror is an advanced technology that is widely used in the laser industry. This type of laser module is characterized by its compact design, in which a laser beam is deflected towards an optical element using a deflection mirror to enable precise light extraction from the laser package. The encapsulated design offers many advantages, such as protection of the laser elements from external influences and easy integration into various applications.

Despite the numerous advantages, there are some potential disadvantages, particularly in the manufacture of the laser packages and in particular in the alignment of the optical element with respect to the optical axis of a semiconductor laser arranged in the laser package.

In known laser packages, two different adhesives are used, applied separately, to fix the optical element to a cover element of the laser package in an aligned position. One of the two adhesives is light-activated or light-curable in order to achieve rapid curing of the adhesive and thus to keep the cycle times for assembling the aligned optical element as short as possible. This adhesive is used accordingly in active adjustment process for quickly attaching the optical element. This first adhesive is usually carbon-based, e.g. acrylate or epoxy-based. However, acrylates and epoxies show aging problems, particularly when exposed to light in the shorter wavelength range (this includes both the wavelength range of blue light and the wavelength range of UV light), and are therefore not stable to light aging. For this reason, a second adhesive is used to ensure a long-term stable connection. The second adhesive is silicone-based, but can only be cured thermally. After being briefly fixed in the correct position, the adhesive hardens in a downstream batch process under thermal influence. Such silicone-based adhesives are stable against aging, but due to their long curing time (thermal curing) they are not suitable for processes in which the optical element has to be set and fixed in position until the adhesive has at least partially hardened.

There is therefore a need to provide a laser package and a laser device comprising at least two laser packages, by means of which at least some of the disadvantages mentioned can be overcome. In addition, there is a need to provide an improved method for producing such a laser package.

SUMMARY OF THE INVENTION

This need is taken into account by the subject matter of the independent patent claims. Further developments and embodiments of the proposed principle are specified in the subclaims.

The inventors propose a laser package in which a silicone-based adhesive is used to assemble an optical element. In addition, the adhesive is light-activated and hardens at least partially when exposed to light. The at least partial hardening leads to a dimensionally stable adhesive bond that holds the optical element at least temporarily in a desired target position before the bond is possibly broken by thermal hardening. can be further cured. The adhesive bond is cured either exclusively by light activation or by light activation with parallel or staggered thermal treatment. The first, at least partial curing of the adhesive, on the other hand, is achieved in short or very short process times of in particular a few seconds or less. After the adhesive has completely cured, a permanently dimensionally stable, solid and radiation-stable connection is created between the base of the laser package and the optical element. The big advantage of the adhesive used is that only one adhesive is needed for the bond between the base of the laser package and the optical element and that process steps can be saved compared to known processes.

According to one aspect of the invention, a laser package comprises a base element that has an arrangement surface on which at least one semiconductor laser element is arranged. In addition, the laser package comprises a cover element that is at least partially transparent to the laser light emitted by the at least one semiconductor laser element, which is connected to the base element and forms a frame that surrounds the at least one semiconductor laser element in a lateral direction and encapsulates the at least one semiconductor laser element with the base element. Furthermore, the laser package comprises a cover element that is essentially transparent to the laser light emitted by the at least one semiconductor laser element, which is arranged on the cover surface, and at least one optical element that is arranged on the cover element. In addition, the laser package comprises at least one deflection element that is arranged in the beam path of the at least one semiconductor laser element and that is designed to deflect a laser light emitted by the at least one semiconductor laser element in the direction of the at least one optical element. The optical element is attached to the cover element by means of a connecting material, wherein the connecting material consists of at least 10 percent, at least 20 percent, at least 50 percent, or at least 80 percent silicone and has a light-curing component, and wherein the connecting material is light-activatable. and is at least partially curable by means of light curing. In particular, the optical element is fastened to the cover element by means of a connecting material, wherein the connecting element is an adhesive which consists partly but at least to 30% of silicone or a silicone mixture, and wherein a subsequent polymerization of the connecting material is light-activated or at least partially triggered by means of light curing.

The "light-curing component" acts as a type of "catalyst" whose mechanism of action is activated by light in order to harden or harden the bonding material. The concentration of the light-curing component can, for example, be in the lower single-digit percentage range, such as in the range of 5, 3 or 2 percent, often even well below one percent. However, the term "catalyst" should not be understood to mean that the light-curing component is used up after it has been activated by light, but rather that it is still present in the hardened bonding material after activation. For example, the silicone portion can be directly stimulated to polymerize using high-energy light, or polymerization can occur indirectly via organic end groups attached to the silicone, which are, for example, acrylate-based.

The connecting material can, for example, comprise a base polymer which has a high silicone content, in particular of at least 80 percent, and a light-curing component, wherein the connecting material is light-activated and at least partially curable by means of light-curing. Such a high silicone content can provide a very high thermal stability as well as a very high blue light stability for the connecting material.

In one aspect, the optical element is attached to the cover element only by means of the connecting material. In particular, no further connecting material or adhesive or other fastening component is required for the connection between the optical element and the cover element. This means that process steps and thus costs can be saved compared to known processes in which Connection between optical element and cover element more than one connecting material or adhesive is required.

In one aspect, the cured bonding material has a binding energy of greater than 350 kJ/mol, greater than 400 kJ/mol or greater than 450 kJ/mol. In particular, the binding energy of a -Si-O-Si bond is approximately 450 kJ/mol, which is why predominantly silicone-based bonding materials are particularly suitable for ageing-stable bonds. In contrast, a -C-C bond (e.g. epoxy) only has a binding energy of approximately 350 kJ/mol, so that such bonding materials with a predominantly -C-C bond portion are not or less suitable for ageing-stable bonds or adhesives. In one aspect, the connecting material can be light-activated by light with a wavelength between 315 nm and 470 nm, or between 250 nm and 450 nm, and can be at least partially cured by means of light curing by light with a wavelength between 315 nm and 470 nm, or between 250 nm and 450 nm. In particular, the connecting material is designed to at least begin to harden or fully harden after irradiation with light with a wavelength between 315 nm and 470 nm, or between 250 nm and 450 nm. This can be understood in particular to mean that the connecting material can be hardened by irradiation with light with a wavelength between 315 nm and 470 nm, or between 250 nm and 450 nm, in such a way that it is at least dimensionally stable and holds the optical element in a desired position relative to the cover element, at least temporarily. The bonding material can then be completely cured by means of a further thermal step or may already have been completely cured by irradiation with light.

In one aspect, the bonding material in the cured state has a high stability against light with a wavelength between 315 nm and 700 nm inclusive. In particular, the bonding material in the cured state can have a high blue light stability. This can be understood in particular to mean that the aging behavior of the bonding material under the influence or. is only insignificantly influenced by the long-term influence of light with a wavelength between 315 nm and 700 nm inclusive. Likewise, the bonding material in the cured state can be highly stable against other external influences, such as the effects of moisture, high temperatures or oxygen, and can therefore be very resistant to aging. For example, the bonding material can be designed in such a way that the final product can withstand long-term (>3000h) irradiation with intense blue light (in particular emitting laser spectrum 430-470 nm) with a light output of at least 20W/cm ² at 100 ° C.

In one aspect, the connecting material is arranged in the form of several adhesive dots or individual adhesive beads between the optical element and the cover element. For example, adhesive dots or individual adhesive beads can be arranged in each corner of the cover element or corners of the optical element, which connect the optical element and the cover element to one another. Furthermore, further adhesive dots can also be arranged between adhesive dots or individual adhesive beads in the corners of the optical element or cover element. However, it can be desired that the connecting material is not arranged in the beam path of the laser light emitted by the semiconductor laser element, but in areas that are not directly in the beam path of the laser light emitted by the semiconductor laser element. The arrangement and number of adhesive dots can be freely selected.

In one aspect, the connecting material is arranged in the form of an adhesive bead or an adhesive surface in line form, in particular a circumferential adhesive bead or adhesive surface in line form between the optical element and the cover element. For example, one or more adhesive beads can be arranged along one or more edges of the cover element or the optical element, which connect the optical element and the cover element to one another. The adhesive bead(s) can in particular be circumferential in such a way that an area within the adhesive bead(s) is sealed between the optical element and the cover element. However, the adhesive bead can also be sub- refractions such that an area within the adhesive bead between the optical element and the cover element is not sealed. However, it may be desirable for the connecting material not to be arranged in the beam path of the laser light emitted by the semiconductor laser element, but rather in areas that are not directly in the beam path of the laser light emitted by the semiconductor laser element. The arrangement and number of the adhesive bead(s) can be freely selected.

In one aspect, the connecting material is designed such that it at least partially hardens by light curing within less than 100 seconds, less than 80 seconds, less than 40 seconds, less than 10 seconds, preferably less than 5 seconds, or even less than 2 seconds, in particular such that it is at least dimensionally stable. Dimensionally stable can be understood in particular to mean that the connecting material holds the optical element relative to the cover element at least temporarily in a desired position so that undesired displacement of the optical element relative to the cover element is prevented. The connecting material can then be fully hardened by means of a further thermal step or may already have been fully hardened by irradiation with light.

In one aspect, the connecting material is designed in such a way that a polymerization of the connecting material is started by light irradiation. Depending on the curing mechanism, this can generally lead to the connecting material solidifying either very quickly through so-called radical cross-linking within the connecting material, for example within one minute, or more slowly through addition cross-linking, for example over five minutes, such that the connecting material solidifies in such a way that a stable positioning of the optical element relative to the cover element is created. The polymerization of the connecting material is essentially based on activating the light-curing component in the form of, for example, photoinitiators by means of light. Such photoinitiators can typically be radical or cationic systems. Different systems and combinations are possible. Such a Polymerization initiated by photoinitiators can also be combined with platinum catalyst-based, addition-curing silicones or components. The curing speed of these can also be accelerated by heat treatment or can contribute to the solidification and adhesion build-up of the bonding material, particularly in shadow areas with poor accessibility for light curing.

In one aspect, the connecting material has at least one inorganic, inert filler and in particular one of the following fillers: Al2O3; Si02; ZrO2, CaF, and AIN. In particular, the filler can be glassy, ceramic or metal-based fillers. The fillers can in particular serve to specifically adjust the rheological properties of the connecting material. This can in particular make it possible to set adhesive gaps between the optical element and the cover element in a range from 5pm to 300pm or even up to 500pm, which is necessary for the active adjustment of the optical element in order to correctly adjust the optical axis of the optical element relative to the beam path of the laser light emitted by the semiconductor laser element. In addition, such inert fillers can also contribute to a particularly low curing shrinkage and improve the thermal stability. However, it is also possible for the connecting material to have at least one organic filler. In such a case, however, it should be ensured that no additional ageing effects are triggered in the connecting material.

In one aspect, the silicone-based bonding material is formed by a radically cross-linking system. In particular, the bonding material can be formed by a radically cross-linking system with acrylic functions, wherein the silicone-based bonding material is designed to be activated by means of a photoinitiator, in particular UV initiator, in order to at least partially harden the bonding material. The photoinitiators can be formed by corresponding chemical compounds which decompose in a photolysis reaction after absorption of (UV) light and thus form reactive species which can start (initiate) a reaction (usually a polymerization) in order to at least harden the bonding material.

In one aspect, the bonding material is formulated with at least one binary mixture of photoinitiators (e.g., with a member of the class of o-hydroxy ketones and a member of the class of acyl phosphine oxides) to optimally utilize a (UV) emission spectrum used on the bonding material for curing and to accelerate the activation of the bonding material.

In one aspect, the bonding material comprises a plurality of different photoinitiators. The use of different photoinitiators may, for example, be advantageous over the use of only one photoinitiator, in particular to provide improved blue light stability of the bonding material. In addition, the use of different photoinitiators may reduce the total proportion of photoinitiators compared to the use of only one photoinitiator, while at the same time the properties of the bonding material remain the same. In particular, the total proportion of photoinitiators in the bonding material may be reduced to less than 3% or substantially 3%, which is particularly advantageous for the light stability of the polymerized bonding material.

In one aspect, the connecting material has one or more additional initiators that can be thermally activated for additional thermal hardening of the connecting material. In particular, the connecting material can be formed by a dual-curing system that has photoinitiator(s) on the one hand and initiator(s) that can be thermally activated on the other. With a connecting material designed in this way, the hardening step can be further optimized in such a way that dimensional stability between the optical element and the cover element can be achieved within a very short time or hardening of the connecting material is facilitated.

In one aspect, the bonding material has a high purity with a content of less than or equal to 1% monomeric impurities. This ensures that the connecting material in the final product has a high level of light stability, particularly blue light stability.

In one aspect, the cover element comprises a frame element which has a ceramic as the main material, which is arranged on the base element adjacent to the base element, and which forms a frame which surrounds the at least one semiconductor laser element in a lateral direction. In addition, the cover element has a substantially transparent element or a substantially transparent cover which is arranged on the frame element or a cover surface of the frame element.

In one aspect, the frame element has a circumferential first step extending laterally from a base surface with a connecting surface which is at least partially connected to a part of the arrangement surface, and the frame element has a circumferential second step extending laterally from a cover surface opposite the base surface.

In one aspect, an optical axis of the at least one optical element is tilted relative to a direction perpendicular to the lateral direction and/or the at least one deflection element is designed to deflect the laser light by less than 90° such that at least a portion of the deflected laser light intersects a region between the rotating second stage and the cover element.

Thanks to the circumferential second step, the deflection element for deflecting the beam of light emitted by the semiconductor laser element can deflect the main axis of the laser beam by an angle of less than 90° to the horizontal in order to direct the laser beam further in the direction of the at least one optical element in the area of an outer edge of the laser package without being shaded by the frame element, as would be the case with a frame element without such a step. The optical element placed on the cover element can thus be pushed onto this outer edge of the laser package in the deflected beam path and its optical axis can be tilted in this way. be such that a vertical light emission from the laser package is nevertheless guaranteed. This type of arrangement allows the emission point of the laser package to be moved as close as possible to one of the outer edges of the laser package without being shaded by the frame element.

In one aspect, the optical axis of the at least one optical element is tilted in the direction of a first side surface of the frame element connecting the base surface and the cover surface. In particular, the at least one optical element also borders on a first plane running through the first side surface and is spaced from a second plane running through a second side surface of the frame element opposite the first side surface. The optical element can in particular be arranged off-center above the at least one semiconductor laser element and in particular very close to one of the outer edges of the laser package. In addition, the optical axis of the at least one optical element is tilted in the direction of this outer edge in order to ensure vertical light exit from the laser package despite the deflection of the laser beam by means of the deflection element of less than 90°.

In one aspect, the laser package is designed to emit laser light in a direction substantially perpendicular to the lateral direction. In addition, the laser package has in particular a laser light emission region that is arranged off-center of the laser package. This laser light emission region is in particular arranged adjacent to the first plane or is arranged along or adjacent to an outer edge of the laser package.

In one aspect, the base element does not protrude beyond the base surface, but is essentially flush with the base surface. The frame element has a surrounding frame, particularly in the area of the surrounding first step, into which the base element is inserted with the aim of creating a substantially flush component underside of the laser package. In one aspect, the base element is arranged at a distance in the lateral direction from a third side surface of the frame element, which connects the base surface and the connecting surface to one another. In particular, the base element is not pressed into the frame element, but is arranged at a distance from the frame element on at least opposite side surfaces of the base element. However, the base element is in particular designed and arranged such that the arrangement surface and the connecting surface have a continuous contact area with one another as seen in the circumferential direction. The frame element can be closed accordingly on one side by means of the base element.

In addition to the at least one deflection element, the laser package can also have further optical elements for beam shaping or beam deflection, which are arranged in the beam path between the at least one semiconductor laser element and the at least one optical element. Such a further optical element for beam shaping or beam deflection can be arranged, for example, on the base plate.

In one aspect, the laser package comprises a plurality of semiconductor laser elements which are arranged at a distance from one another on the base element and are surrounded by the cover element in the lateral direction. In particular, one or more semiconductor laser elements can be provided in the laser package in order to emit light of the same or different wavelengths. For example, the laser package can be provided to emit only short-wave laser light in the range of, for example, 450 nm, which is then converted into a desired color. Alternatively, the laser package can be provided to emit light of different wavelengths, for example red, green and blue light, and accordingly form an RGB laser package. However, any other combination of wavelengths/colors which can be emitted by the laser package by means of several semiconductor laser elements is also conceivable.

In one aspect, the semiconductor laser elements of the plurality of semiconductor laser elements may be arranged in a row next to one another. In particular, the semiconductor laser elements can be arranged equidistantly or at different distances from one another on the base plate.

In one aspect, the laser package comprises a plurality of optical elements, each of which, for example, has an optical axis that is tilted with respect to a direction perpendicular to the lateral direction. In particular, the laser package comprises an optical element that is assigned to a semiconductor laser element. In the case of a plurality of semiconductor laser elements, the laser package can have the same number of optical elements as the number of semiconductor laser elements. However, it is also conceivable that the optical element is formed by a lens array that has a plurality of optical axes, with each semiconductor laser element being assigned an optical axis.

In one aspect, the laser package comprises a plurality of deflection elements, each of which is arranged in the beam path of one of the plurality of semiconductor laser elements and is designed to deflect a laser light emitted by the corresponding semiconductor laser element in the direction of the at least one first optical element. In particular, the laser package in each case comprises a deflection element that is assigned to a semiconductor laser element. In the case of a plurality of semiconductor laser elements, the laser package can have the same number of deflection elements as the number of semiconductor laser elements. However, it is also conceivable that the deflection element is formed by a continuous mirror that deflects the light emitted by the semiconductor laser elements in each case by substantially 90 ° or by less than 90 ° in the direction of the at least one optical element.

In one aspect, contact surfaces are arranged on the circumferential second stage, which are electrically coupled to at least one of the plurality of semiconductor laser elements. In particular, the circumferential second stage has contact surfaces on its upper side, which are electrically connected via internal conductor tracks and vias, for example, to the bottom surface of the frame element. The conductor tracks Tracks or through-holes can be formed in particular by contact levels integrated into the frame element, which are electrically connected to the contact surfaces. The frame element can be designed for example as a multilayer ceramic (e.g.: AI2O3, AIN). In particular, the contact surfaces on the circumferential second step can be designed at different heights in order to facilitate contacting of the contact surfaces or arrangement of the contact levels. The contact surfaces at different heights in the circumferential second step are connected, for example, to different connection levels in the frame element.

In one aspect, the plurality of semiconductor laser elements are coupled to one another in series. In particular, the two outer semiconductor laser elements coupled in series can be contacted by means of bonding wires to contact surfaces on the circumferential second stage.

In one aspect, however, at least two of the plurality of semiconductor laser elements are each electrically coupled to at least two contact surfaces on the rotating second stage in such a way that each of the at least two of the plurality of semiconductor laser elements can be operated individually. In particular, with the help of the contact surfaces in or on the rotating second stage in conjunction with corresponding internal wiring in the frame element, it is possible to control several semiconductor laser elements mounted in the laser package independently of one another. In the case of an RGB laser package, for example, this can be particularly advantageous since it enables a desired color mixture of the light emitted by the laser package to be achieved. The rotating second stage offers the advantage that a corresponding surface for providing the contact surfaces is provided adjacent to the respective semiconductor laser elements and wiring between the semiconductor laser element and contact surfaces is possible over a short distance and without contact with other components of the laser package. Contacting of the semiconductor laser elements with the contact surfaces can be achieved, for example, by means of bonding wires to the contact surfaces on the circumferential second stage. In one aspect, the base element has a ceramic as the main material and in particular has a metallic coating at least in some areas and/or electrical vias. The ceramic base element can comprise, for example, AIN or SiC and have a metallic coating at least in some areas and/or electrical vias. Alternatively, the base element can be formed substantially completely from a metallic material such as Cu or a Cu-based alloy.

In one aspect, a submount is arranged between the at least one semiconductor laser element and the base plate. In particular, the at least one semiconductor laser element and the submount can form a sub-assembly that is arranged on the assembly surface. The submount can, on the one hand, enable better heat dissipation from the at least one semiconductor laser element and, on the other hand, can represent an elevation in order to prevent so-called beam clipping of the laser light emitted from a laser facet of the at least one semiconductor laser element. The submount can, for example, be made of metal, or have a ceramic as the main material and in particular have a metallic coating at least in some areas and/or electrical vias. In particular, the laser package comprises a submount that is assigned to a semiconductor laser element. In the case of a large number of semiconductor laser elements, the laser package can have the same number of submounts as the number of semiconductor laser elements. However, it is also conceivable that only one continuous submount is provided on which the semiconductor laser elements are arranged. Furthermore, it is also conceivable that several submounts have different heights, such that the semiconductor laser elements are also arranged at different heights and emit laser light at different heights. This can be particularly advantageous since several deflection elements and optical elements can also be arranged at different heights and can thus be laterally offset from one another in order to enable an even more compact arrangement of the elements in order to further increase the luminance of the LES. In one aspect, the laser package further comprises at least one electrical component which is arranged on the second stage or is integrated into the frame element in the region of the second stage and is electrically coupled to contact surfaces on the circumferential second stage. The circumferential second stage can be designed accordingly for the integration of additional functions. For example, at least one of the following components can be arranged on the second stage or integrated into the frame element in the region of the second stage: ESD protection diode, photodiode with monitoring function, NTC as temperature sensor, capacitor as voltage source, other passive electrical components.

In one aspect, the at least one semiconductor laser element is hermetically encapsulated in the interior between the base element and the cover element. In particular, the cover element and the base element can be hermetically joined together. For this purpose, connecting elements between the components can be formed, for example, by a metallic solder (Cu/Sn; Cu/Sn/Ag) or by a glass. This results in a hermetically encapsulated laser package that prevents rapid aging of the semiconductor laser elements.

A further aspect relates to a laser device comprising a plurality of laser packages according to at least one of the aspects described above. In this case, two laser packages are arranged adjacent to one another in such a way that the optical axes of the optical elements of the two laser packages are arranged adjacent to one another or are mirrored. The laser packages are arranged in particular in a so-called vis-a-vis arrangement in such a way that the individual light points of the laser packages arranged next to one another are arranged as close to one another as possible. In particular, the laser device comprises an even number of laser packages, with two of the laser packages always being arranged in a vis-a-vis arrangement and pairs of laser packages being arranged in rows and/or columns.

Such a laser device can also be referred to as a cluster of laser packages and can be used as a light source for laser projection applications. In one aspect, the plurality of laser packages are arranged on a common carrier substrate, in particular a printed circuit board. For example, the carrier substrate can be formed by a so-called "exposed copper board" on which the laser packages are arranged.

A further aspect relates to a method for producing a laser package comprising the steps:

Providing a:

bottom element having an arrangement surface on which at least one semiconductor laser element is arranged,

Deflection element which is arranged in the beam path of the at least one semiconductor laser element, and cover element which is at least partially transparent for the laser light emitted by the at least one semiconductor laser element, which is connected to the base element and which forms a frame which surrounds the at least one semiconductor laser element in a lateral direction and encapsulates the at least one semiconductor laser element on the base element;

Providing a light-activatable and at least partially light-curable bonding material on the cover element, wherein the bonding material consists of at least 10 percent, at least 20 percent, at least 50 percent, or at least 80 percent silicone or comprises a silicone mixture and comprises a light-curing component;

Arranging an optical element on the connecting material;

Aligning the optical element such that a laser light emitted by the at least one semiconductor laser element and deflected by the deflection element radiates through the optical element; and

Light curing of the connecting material in particular such that it is at least dimensionally stable, in particular by means of light with a wavelength between 315 nm and 470 nm. In one aspect, the light-curing step takes place for less than 100 seconds, in particular less than 80 seconds, in particular less than 40 seconds, in particular less than 20 seconds, in particular less than 20 seconds, preferably less than 5 seconds or even less than 2 seconds. The light-curing step of less than 100 seconds, less than 80 seconds, less than 40 seconds, less than 10 seconds, preferably less than 5 seconds, or even less than 2 seconds at least partially cures the connecting material, in particular in such a way that it is at least dimensionally stable. Dimensionally stable can be understood in particular to mean that the connecting material holds the optical element in a desired position relative to the cover element at least temporarily, so that undesired displacement of the optical element relative to the cover element is prevented. The connecting material can then be fully cured by means of a further thermal step or can already have been fully cured by irradiation with light.

In one aspect, the method further comprises thermally curing the bonding material after the light-curing step. Through the thermal curing step, the already cured and in particular dimensionally stable bonding material can be completely cured with further exposure to light or just heat.

In one aspect, the light-curing step takes place essentially at room temperature. In particular, the light-curing step can take place essentially at room temperature, i.e. around 22°C. However, it can also be advantageous for the light-curing step to take place at a temperature greater than room temperature, i.e. greater than 22°C. For example, depending on the composition of the bonding material, an appropriate ambient temperature for the light-curing step can be selected in order to ensure optimal curing of the bonding material during the light-curing step. For example, the bonding material can comprise in addition to photoinitiators also initiators which, under the influence of elevated temperature, activated so that the light-curing step can be accelerated at a temperature above room temperature.

In one aspect, the bonding material in the cured state has a high blue light stability. In particular, the bonding material in the cured state has a high stability against light with a wavelength between 315nm and 700nm inclusive. This can be understood in particular to mean that the aging behavior of the bonding material is only insignificantly affected by light with a wavelength between 315nm and 700nm inclusive. Likewise, the bonding material in the cured state can have a high stability against other external influences, such as the effects of moisture, high temperatures or oxygen, and can therefore be very stable against aging. For example, the bonding material can be designed in the final product to withstand long-term (>3000h) irradiation with intense blue light (in particular emitting laser spectrum 430-470nm) with a light output of at least 20W/ ^cm2 at 100 °C.

In one aspect, the step of providing the base, deflection and at least one semi-elliptical laser element comprises inserting the base element into a frame element. This can, for example, comprise gluing or bonding the base element into the frame element. In particular, the step of inserting the base element into the frame element can comprise hermetically joining the base element into the frame element.

In one aspect, the step of providing the base, deflection and the at least one semiconductor laser element comprises arranging the at least one semiconductor laser element on the arrangement surface. This can in particular comprise gluing or bonding the at least one semiconductor laser element on the arrangement surface. Furthermore, the step can comprise arranging a submount on the arrangement surface and subsequently arranging the at least one semiconductor laser element on the submount. In addition, the step arranging a subassembly comprising a submount and the at least one semiconductor laser element on the arrangement surface.

In one aspect, the step of providing the ground, deflection and at least one half-elite laser element comprises arranging the at least one deflection element. This may comprise arranging and aligning the deflection element on the arrangement surface.

In one aspect, the step of providing the base, deflection and at least one semiconductor laser element comprises providing the cover element, which is at least partially transparent to the laser light emitted by the at least one semiconductor laser element, in the form of providing a substantially transparent cover on a cover surface of a frame element. In particular, the step can comprise gluing or bonding the substantially transparent cover to the frame element, and in particular hermetically joining the substantially transparent cover to the frame element.

The method for producing a laser package can in particular be a method for producing a laser package according to at least one of the aspects described above, so that the aspects described for the laser package are also applicable to the laser package produced by means of the method.

SHORT DESCRIPTION OF THE DRAWINGS

Further aspects and embodiments according to the proposed principle will become apparent with reference to the various embodiments and examples which are described in detail in connection with the accompanying drawings.

Figures 1A to 1C show a cross-sectional view and two plan views of a laser device; Figures 2A to 2C show a cross-sectional view and two plan views of a laser device comprising two laser packages according to some aspects of the proposed principle;

Figures 3A and 3B show a cross-sectional view and a plan view of another embodiment of a laser device comprising laser packages according to some aspects of the proposed principle;

Figure 4 shows a cross-sectional view of another embodiment of a laser device comprising laser packages according to some aspects of the proposed principle; and

Figure 5 shows a cross-sectional view of another embodiment of a laser device comprising laser packages according to some aspects of the proposed principle.

DETAILED DESCRIPTION

The following embodiments and examples show various aspects and their combinations according to the proposed principle. The embodiments and examples are not always to scale. Likewise, various elements can be shown enlarged or reduced in size in order to emphasize individual aspects. It goes without saying that the individual aspects and features of the embodiments and examples shown in the figures can easily be combined with one another without affecting the inventive principle. Some aspects have a regular structure or shape. It should be noted that in practice, slight deviations from the ideal shape can occur without, however, contradicting the inventive idea.

In addition, the individual figures, features and aspects are not necessarily shown in the correct size, and the proportions between the individual elements need not be fundamentally correct. Some aspects and features are emphasized by showing them in an enlarged manner. However, terms such as "top", "above", "bottom", "below", "larger", "smaller" and the like are correctly shown in relation to the elements in the figures. It is thus possible to derive such relationships between the elements from the illustrations.

Figures 1A, 1B and 1C show a cross-sectional view and two plan views of a laser device comprising two laser packages, each with a base element 2 which has an arrangement surface 3 on which semiconductor laser elements 4 are arranged. The laser packages also each comprise a cover element 11 comprising a frame element 5 which is connected to the base element 2 and which forms a frame which surrounds the semiconductor laser elements 4 in a lateral direction x. The frame element 5 has a circumferential step 7 extending from a base surface 6 in the lateral direction and having a connecting surface 8 which is connected to the arrangement surface 3. Furthermore, the cover elements 11 each comprise a substantially transparent cover 19 which is arranged on a cover surface 9 of the frame element 5 which is opposite the base surface. Furthermore, a deflection element 14 is arranged on the arrangement surface 3 in the beam path of the semiconductor laser elements 4, which deflects a laser light L emitted by the semiconductor laser elements 4 by 90° in the direction of optical elements 12. The optical elements 12 are arranged in such a way that their optical axis 13 runs perpendicularly and along the main axis of the deflected laser light L in order to ensure laser light emission in a direction y of the laser packages that is perpendicular to the lateral direction x.

The optical elements 12 are attached to the cover element 11 or the essentially transparent cover 19 by means of two different adhesives 26a and 26b, which are applied in the form of adhesive dots in the corners of the cover element 11. Figure 1B shows a top view of a state in which the optical elements 12 have not yet been applied to the adhesive dots and Figure 1C shows a state in which the optical elements 12 have been applied to the adhesive dots. have been. A first 26a of the two adhesives is light-activated or hardenable in order to achieve rapid hardening of the adhesive and thus to keep cycle times during assembly of the aligned optical element 12 short. This adhesive is used accordingly in the active adjustment process for quickly attaching the optical element 12. This first adhesive 26a is usually carbon-based, e.g. acrylate or epoxy-based. However, acrylates and epoxies show aging problems, particularly in the shorter wavelength range (this includes both the wavelength range of blue light and the wavelength range of UV light), and are therefore not light-aging stable. For this reason, the second adhesive 26b is used to ensure a long-term stable connection. The second adhesive 26b is silicone-based, but can only be cured thermally. The second adhesive 26b is cured after the optical element 12 has been briefly fixed in the correct position in a subsequent batch process under thermal influence. Such silicone-based adhesives are resistant to aging, but due to their long curing time (thermal curing) they are not suitable for processes in which the optical element 12 has to be set and fixed in its position until the adhesive has at least partially cured.

The inventors therefore propose a laser package 1 in which only a silicone-based connecting material 26 is required for mounting an optical element 12. The connecting material is light-activated and hardens at least partially by irradiation with light. The at least partial hardening leads to a dimensionally stable adhesive bond that holds the optical element 12 at least temporarily in a desired target position before the bond can be further hardened by thermal hardening if necessary. The bond is accordingly hardened either exclusively by light activation or by light activation with parallel or staggered thermal treatment. The first, at least partial hardening of the connecting material 26 is achieved in short or very short process times of in particular a few seconds or less. After the connecting material has completely hardened, The use of the bonding material 26 creates a permanently dimensionally stable, solid and radiation-stable connection between the base package of the laser package 1 and the optical element 12. The great advantage of the bonding material 26 used is that only one bonding material 26 is required for the connection between the base package of the laser package 1 and the optical element 12 and that process steps can be saved compared to the device shown in Figures 1A to 1C.

The laser device 100 proposed by the inventors and shown in Figures 2A to 2C comprises two laser packages 1 each with a cover element 11 comprising a frame element 5, in which the frame element 5 together with a base element 2 forms a cavity for at least one semiconductor laser element 4.

Subassemblies comprising a submount 22 and a semiconductor laser element 4 are arranged on an arrangement surface 3 of the base element 2. The laser packages 1 can each have one or more such subassemblies, i.e. one or more semiconductor laser elements 4, which are arranged on the base element.

The frame elements 5 have a ceramic as the main material and are each connected to the base element 2. Furthermore, the frame elements 5 form a frame that surrounds the semiconductor laser elements 4 in a lateral direction x. The frame element 5 has a circumferential first step 7 extending from a base surface 6 in the lateral direction with a connecting surface 8 that is connected to the arrangement surface 3.

Furthermore, the cover elements 11 each comprise a substantially transparent cover 19, which is arranged on the cover surface 9 of the frame element 5 and, together with the frame element 5 and the base element 2, forms a closed interior space 24 of the laser package 1. An optical element 12 is fastened to the cover element 11 or the substantially transparent cover 19 by means of the connecting material 26. The connecting material 26 is applied in the form of adhesive dots in the corners of the cover element 11. Figure 2B shows a top view of a state in which the optical elements 12 have not yet been applied to the adhesive points and Figure 2C shows a state in which the optical elements 12 have been applied to the adhesive points. The arrangement of the connecting material 26 is, however, only to be understood as an example and can also be in the form of adhesive bead(s) or several adhesive points.

The connecting material 26 is in particular a silicone-based and light-activatable adhesive that hardens at least partially by irradiation with light. The at least partial hardening leads to a dimensionally stable adhesive bond that holds the optical element 12 at least temporarily in a desired target position before the bond can be further hardened by thermal hardening if necessary. The adhesive bond is accordingly hardened either exclusively by light activation or by light activation with parallel or staggered thermal treatment.

In addition, a deflection element 14 is arranged on the arrangement surface 3 in the beam path of the semiconductor laser elements 4, which deflects a laser light L emitted by the semiconductor laser elements 4 in the direction of the optical elements 12. The deflection element 14 is designed such that it deflects the laser light L emitted by the semiconductor laser elements 4 by an angle of essentially 90° in the direction of the optical element 12.

In the embodiments shown, the base element 2 essentially does not protrude beyond the base surface 6 and is essentially flush with the base surface 6. This has the advantage that a flat application to the carrier substrate 25 is possible, so that the mechanical stability of the laser device 100 is increased and electrical contacts can also be provided over the entire contact surface between the laser packages and the carrier substrate 25 for operating the laser packages 1.

In addition to the embodiment shown in Figures 2A to 2C, the embodiment shown in Figures 3A and 3B comprises a frame element 5 in which an inner side wall of the frame element 5 on an upper side of the laser package 1 or starting from a cover surface 9 of the frame element 5 has a circumferential step 10 which has several functions. Firstly, the circumferential step 10 causes the inner side wall of the frame element 5 to be set back in the region of the circumferential step 10, and as a result shading of a laser light L emitted by the at least one semiconductor laser element 4 can be avoided, and secondly, the circumferential step 10 can be used according to developments of the invention to provide further functionalities of the laser package 1 in or on it. Thanks to the circumferential step 10, a deflection mirror 14 for deflecting a laser light L emitted by the semiconductor laser element 4 can deflect the main axis of the laser light L by an angle of less than 90° to the horizontal in order to direct the laser light L further in the direction of an outer edge of the laser package 1 without being shaded by the frame element 5, as would be the case with a frame element according to the embodiments described above. A lens 12 placed on the cover element 11 can then be pushed onto this outer edge of the laser package 1 in the deflected beam path of the laser light L and its optical axis 13 can be tilted in such a way that a vertical light exit from the laser package 1 is ensured. This type of arrangement allows the emission point of the laser package 1 to be pushed as close as possible to one of the outer edges of the laser package 1, so that in the case of a laser device 100 which, similar to that in Figures 2A and 2C, the main axes of the laser light L emitted by the laser packages 1 have a comparatively smaller distance d from one another. In the case of such a laser device 100, in which the laser packages 1 are arranged in such a way that the emission points of the laser packages 1 are arranged directly next to one another and only at a distance d from one another, the luminance within a jointly emitting light emission surface (LES) of the laser device 100 can be significantly increased compared to a laser device as shown in Figures 2A and 2C.

Figures 3A and 3B show a cross-sectional view and a plan view of such a laser device 100 comprising two laser packages 1. The laser device 100 has two laser packages 1, each with a base element 2, which has an arrangement surface 3 on which subassemblies consisting of a submount 22 and a semiconductor laser element 4 are arranged. The laser packages 1 can each have one or more such subassemblies, i.e. one or more semiconductor laser elements 4, which are arranged on the base element.

The cover elements 11 also each comprise a frame element 5 which has a ceramic as the main material, which is connected to the base element 2, and which forms a frame which surrounds the semiconductor laser elements 4 in a lateral direction x. The frame element 5 has a circumferential first step 7 extending from a base surface 6 in the lateral direction with a connecting surface 8 which is connected to the arrangement surface 3, and a circumferential second step 10 extending from a cover surface 9 opposite the base surface 6 in the lateral direction x.

Furthermore, the cover elements 11 each comprise a substantially transparent cover 19, which is arranged on the cover surface 9 of the frame element 5 and, together with the frame element 5 and the base element 2, forms a closed interior space 24 of the laser package 1. An optical element 12 is fastened to the cover element 11 or to the substantially transparent cover 19 by means of the connecting material 26. In addition, a deflection element 14 is arranged on the arrangement surface 3 in the beam path of the semiconductor laser elements 4, which deflects a laser light L emitted by the semiconductor laser elements 4 in the direction of the optical elements 12. The optical elements can in particular be a glass plate with integrated micro-optics(s). Such an embodiment can be particularly advantageous since the joints between the cover element 11 and the optical element 12 are located outside the area through which the laser light shines. Accordingly, the efficiency of the laser packages 1 can be increased.

The deflection element 14 is designed such that it deflects the laser light L emitted by the semiconductor laser elements 4 by an angle a of less than 90° in such a way that at least part of the deflected laser light L intersects a region 15 between the rotating second stage 10 and the essentially transparent cover 19. In addition, the optical elements 12 are arranged and aligned in such a way that their optical axis 13 is tilted with respect to a direction y perpendicular to the lateral direction x in order to ensure laser light emission in a direction y of the laser packages 1 perpendicular to the lateral direction x. The optical elements 12 can accordingly realign the laser light L running "obliquely" through the region 15 so that it exits the laser packages 1 in a direction y perpendicular to the lateral direction x.

By deflecting the laser light by less than 90°, it is possible to guide a light emission closer to an edge region of the laser package 1, and by means of the optical elements 12, the laser light L running "obliquely" through the region 15 can then be realigned. In the illustrated case of two laser packages 1 arranged opposite one another on a carrier substrate 25, the main axes of the laser light L emitted by the laser packages 1 can be pushed together accordingly up to a distance d in the lateral direction x, so that compared to the embodiment of Figures 2A and 2C, the luminance can be increased within a lower LES due to the same light output emitted by the laser packages 1.

In particular, the optical axes 13 of the optical elements 12 are tilted in the direction of a first side surface 16a of the frame element 5, which connects the bottom surface 6 and the cover surface 9, in order to achieve the alignment of the laser light L running "obliquely" through the region 15. In the laser device, the side surfaces 16a of the laser packages 1 are arranged opposite one another in such a way that the desired vis-a-vis arrangement is obtained. In addition, the optical elements 12 border on a first plane 17a running through the first side surface 16a and are spaced from a second plane 17b running through a second side surface 16b of the frame element 5 opposite the first side surface 16a in order to achieve light emission of the Laser packages at their edge. A laser light emission region 18 of the laser packages is thus arranged off-center above the region 15 and in particular adjacent to the first plane 17a.

In the embodiments shown, the base element 2 essentially does not protrude beyond the base surface 6 and is essentially flush with the base surface 6. This has the advantage that a flat application to the carrier substrate 25 is possible, so that the mechanical stability of the laser device 100 is increased and electrical contacts can also be provided over the entire contact surface between the laser packages and the carrier substrate 25 for operating the laser packages 1.

In addition, the base element 2 is arranged at a distance in the lateral direction from a third side surface 16c of the frame element 5, which connects the base surface 6 and the connecting surface 8 to one another. In particular, the base element 2 is glued or bonded to the connecting surface 8 and not pressed into the frame element 5, which causes the distance shown. For example, the base element 2 and the frame element 5 can be hermetically joined.

From the top view 2B it can be seen how the optical element 12 of a laser package 1 and the respective associated underlying semiconductor laser elements 4 are arranged in series along an outer edge of the laser package 1. A laser light emitted from the optical elements 12 of the two laser packages 1 can together form a jointly emitting light emission surface (LES) of the laser device 100.

The embodiment shown in Figure 4 differs from the embodiment shown in Figure 2A in that the cover element 11 or the frame element 5 is arranged on the base element 2, in particular in such a way that the base element 2 forms a support for the frame element and is not arranged in a step of the frame element. In addition, the base element is made of a ceramic as the main material and has through-plating(s) and contact surfaces via which the semiconductor laser element 4 is electrically connected. In addition, the frame element 5 and the base element 5 have bonding surfaces by means of which a connection is created between the base element 2, the frame element 5 and the essentially transparent cover 19. However, this is to be understood as merely an example, and the described features of the base element 2 and the bonding surfaces can also be transferred to the other embodiments of the proposed principle.

The embodiment shown in Figure 5 differs from the embodiment shown in Figure 4 in that the cover element 11 is formed by a one-piece or one-piece essentially transparent cover which is connected to the base element 2 and which forms a frame which surrounds the semiconductor laser element 4 in the lateral direction x and encapsulates the semiconductor laser element 4 with the base element 2. For example, the cover element 11 can be formed from a glass in such a case.

REFERENCE SYMBOL LIST

1 laser package

2 floor elements

3 arrangement area

4 semiconductor laser element

5 frame element

6 floor area

7 circumferential steps

8 connecting surface

9 lid surface

10 circumferential steps

11 cover element

12 optical elements

13 optical axis

14 deflection element

15 area

16a, 16b, 16c side surface

17a, 17b level

18 laser light emission area

19 cover

22 submount

24 interior

25 carrier subs stepped

26 connecting material

26a, 26b Adhesive x direction y direction

L laser light d distance

Claims

PATENT CLAIMS 1. Laser package (1) comprising: a base element (2) which has an arrangement surface (3) on which at least one semiconductor laser element (4) is arranged; a cover element (11) which is at least partially transparent to the laser light (L) emitted by the at least one semiconductor laser element (4), which is connected to the base element (2), which forms a frame which surrounds the at least one semiconductor laser element (4) in a lateral direction (x), and which encapsulates the at least one semiconductor laser element (4) with the base element (2); an optical element (12) which is arranged on the cover element (11); and at least one deflection element (14) which is arranged in the beam path of the at least one semiconductor laser element (4) and is designed to deflect a laser light (L) emitted by the at least one semiconductor laser element (4) in the direction of the at least one optical element (12); wherein the optical element (12) is fastened to the cover element (11) by means of a connecting material (26), wherein the connecting material (26) has: at least 30 percent silicone content; a light-curing component; and wherein the connecting material (26) is light-activatable and at least partially curable by means of light-curing. 2. Laser package according to claim 1, wherein the optical element (12) is attached to the cover element (11) only by means of the connecting material (26). 3. Laser package according to claim 1 or 2, wherein the connecting material (26) has an internal binding energy of greater than 400 kJ/mol. 4. Laser package according to one of claims 1 to 3, wherein the connecting material (26) is irradiated by light having a wavelength between 315 nm and 470nm light-activated and at least partially curable by light curing with light having a wavelength between 315nm and 470nm. 5. Laser package according to one of claims 1 to 4, wherein the connecting material (26) in the cured state has a high stability against light with a wavelength between 315 nm and 700 nm inclusive. 6. Laser package according to one of claims 1 to 5, wherein the connecting material (26) is arranged in the form of several adhesive dots or several non-contiguous adhesive beads between the optical element (12) and the cover element (11). 7. Laser package according to one of claims 1 to 5, wherein the connecting material (26) is arranged in the form of a circumferential adhesive bead between the optical element (12) and the cover element (11), wherein in particular the circumferential adhesive bead has interruptions. 8. Laser package according to one of claims 1 to 7, wherein the connecting material (26) is designed such that it at least partially hardens by light curing within less than 5 seconds, in particular such that it is at least dimensionally stable. 9. Laser package according to one of claims 1 to 8, wherein the connecting material (26) comprises at least one of the following fillers: A12O3; Si02; ZrO2; CaF; and AIN. 10. Laser package according to one of the preceding claims, comprising a plurality of semiconductor laser elements (4) which are arranged at a distance from one another on the base element (2) and are surrounded and encapsulated by the cover element (11) in the lateral direction (x). 11. Laser package according to one of the preceding claims, wherein the cover element (11) has a frame element (5) which has a ceramic as the main material, wherein the frame element (5) is arranged adjacent to the base element (2) and surrounds the at least one semiconductor laser element (4) in a lateral direction (x). 12. Laser package according to claim 11, wherein the frame element (5) has a circumferential first step (7) extending from a bottom surface (6) in the lateral direction with a connecting surface (8) which is at least partially connected to a part of the arrangement surface (3), and wherein the frame element (5) has a circumferential second step (10) extending from a cover surface (9) opposite the bottom surface (6) in the lateral direction (x). 13. Laser package according to claim 12, wherein an optical axis (13) of the at least one optical element (12) is tilted relative to a direction (y) perpendicular to the lateral direction (x), and wherein the at least one deflection element (14) is designed to deflect the laser light (L) by an angle (o) of less than 90° such that at least a portion of the deflected laser light (L) intersects a region (15) between the circumferential second step (10) and a substantially transparent region of the cover element (11). 14. Laser package according to one of claims 11 to 13, comprising a plurality of optical elements (12), each having an optical axis (13) which is tilted with respect to a direction (y) perpendicular to the lateral direction (x). 15. Laser package according to one of claims 11 to 14, comprising a plurality of deflection elements (14), which are each arranged in the beam path of one of the plurality of semiconductor laser elements (4) and are designed to deflect a laser light (L) emitted by the corresponding semiconductor laser element (4) in the direction of the at least one optical element (12). 16. Laser package according to one of the preceding claims, wherein a submount (22) is arranged between the at least one semiconductor laser element (4) and the base plate (2). 17. Laser package according to one of the preceding claims, wherein the at least one semiconductor laser element (4) is hermetically encapsulated in the interior space (24) between the base element (2) and the cover element (11). 18. Laser device (100) comprising a plurality of laser packages (1) according to one of the preceding claims, wherein two laser packages (1) are arranged adjacent to one another in such a way that the optical axes (13) of the optical elements (12) of the two laser packages (1) are arranged adjacent to one another. 19. Laser device according to claim 17, wherein the plurality of laser packages (1) are arranged on a common carrier substrate (25), in particular a printed circuit board. 20. Method for producing a laser package (1) comprising the steps: Providing a: bottom element (2) having an arrangement surface (3) on which at least one semiconductor laser element (4) is arranged, deflection element (14) which is arranged in the beam path of the at least one semiconductor laser element (4), and a cover element (11) which is at least partially transparent for the laser light (L) emitted by the at least one semiconductor laser element (4), which is connected to the base element (2) and which forms a frame which surrounds the at least one semiconductor laser element (4) in a lateral direction (x) and encapsulates the at least one semiconductor laser element (4) on the base element (2); Providing a light-activatable and at least partially light-curable connecting material (26) on the cover element (11), wherein the connecting material (26) comprises at least 30 percent silicone and comprises a light-curing component; Arranging an optical element (12) on the connecting material (26); Aligning the optical element (12) such that a laser light (L) emitted by the at least one semiconductor laser element (4) and deflected by the deflection element radiates through the optical element (12); and Light curing the connecting material (9) such that it is at least dimensionally stable, in particular by means of light with a wavelength between 315 nm and 470 nm. 21. The method of claim 20, wherein the step of light curing is performed for less than 5 seconds. 22. The method of claim 20 or 21, wherein the step of light curing occurs substantially at room temperature. 23. The method of any one of claims 20 to 22, further comprising thermally curing the bonding material (26) after the light curing step. 24. Method according to one of claims 20 to 23, wherein the connecting material (26) has a high blue light stability in the cured state.