Multi-laser device and housing cover for multi-laser device

Abstract

The present invention relates to a multi-laser device having multiple lasers, a housing cover for such a multi-laser device, and a method for manufacturing the housing cover, wherein the housing cover has an upper wall, a side wall and an opening, the side wall being integrally constructed with the upper wall and ending at a lower edge, the opening being for electromagnetic radiation to pass through, and wherein the side wall has a first thickness measured in a direction perpendicular to its surface, and a second thickness at the lower edge, particularly in the same direction, the second thickness being less than or equal to the first thickness.

Description

Technical Field

[0001] This invention relates to a multi-laser device, and more particularly to an RGB laser module, and a housing cover for such a multi-laser device. Background Technology

[0002] Multi-laser devices are particularly useful in products that reproduce augmented reality (AR) or virtual reality (VR), such as AR glasses or VR glasses. A multi-laser device is a component with multiple lasers that project images onto the user's retina. In this case, three edge-emitting lasers (EELs) are typically used, with one laser emitting in the red wavelength range, one in the green wavelength range, and one in the blue wavelength range.

[0003] To ensure a reliable lifespan, the three lasers are encapsulated, particularly in a hermetically sealed housing to exclude moisture. Crucially, blue laser diodes typically require such a housing to achieve their expected lifespan.

[0004] Users demand AR or VR products, especially AR or VR glasses, that are indistinguishable from traditional products or glasses in appearance, offer the highest possible comfort when worn, and provide high image quality. Therefore, there is a growing expectation for miniaturized, lightweight, and optimized multi-laser devices. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a multi-laser device, particularly an RGB laser module, a housing cover for such a multi-laser device, and a method for manufacturing the housing cover, which achieves miniaturization, weight reduction, and / or image optimization.

[0006] To achieve this objective, the present invention provides a multi-laser device, particularly an RGB laser module, which includes a housing and a plurality of lasers arranged within the housing.

[0007] The housing includes a substrate and a housing cover fixed to the substrate, wherein the housing cover includes at least one opening for electromagnetic radiation to pass through, the opening having a transparent element assigned to the opening.

[0008] These lasers are specifically configured as a first laser emitting in the red spectral range, a second laser emitting in the green spectral range, and a third laser emitting in the blue spectral range.

[0009] The lasers are arranged inside the housing, spaced apart from the bottom surface of the substrate, and preferably arranged on a platform. The lasers are preferably configured as edge-emitting lasers (EELs).

[0010] The housing cover includes an upper wall and a side wall, the side wall being integrally formed with the upper wall and ending at a lower edge fixed to the base plate.

[0011] In addition, the sidewall has a first thickness measured in a direction perpendicular to its surface, and a second thickness at the lower edge, particularly in the same direction, which is less than or equal to the first thickness.

[0012] This allows for smaller structural designs and / or avoidance or minimization of lateral protrusions at the lower edge. In particular, it reduces the metallization width (pad width) on spare parts (especially substrates, such as ceramic substrates), which contributes to component miniaturization or increases the construction space within the housing.

[0013] In a preferred embodiment, the sidewall has an outwardly curved surface at the lower edge inside the housing cover, such that the thickness of the sidewall gradually decreases towards the lowest point of the sidewall.

[0014] The sidewall may be configured to have no protrusion at the lower edge on the outer side, or the sidewall may have a protrusion, which is preferably less than the first thickness, particularly preferably less than half of the first thickness, and even more preferably less than one-quarter of the first thickness.

[0015] Preferably, the lower edge of the sidewall is fixed to the substrate in such a way that a connecting material (e.g., welding material) is introduced between the lower edge of the sidewall and the substrate, preferably in a region that is shorter than the first or second thickness of the sidewall along the direction of the first or second thickness of the sidewall.

[0016] The lower edge of the sidewall is fixed to the substrate in such a way that a connecting material (e.g., welding material) is introduced between the outwardly curved surface inside the housing cover and the substrate, in particular, the connecting material protrudes higher from the substrate inside the housing cover compared to the lower edge of the sidewall and the substrate.

[0017] Alternatively or additionally, the lower edge of the sidewall is fixed to the substrate in such a way that a connecting material is introduced between the outer side of the sidewall and the substrate, for example, between the protrusion and the substrate, and in particular, the connecting material protrudes higher from the substrate at the outer side of the housing cover compared to the lower edge of the sidewall and the substrate.

[0018] The sidewalls can be constructed in such a way that they gradually narrow at the lower edge, especially along the direction from the upper edge to the lower edge.

[0019] Preferably, the second thickness of the sidewall, measured at the lower edge, may be at least 5%, preferably at least 10%, particularly preferably at least 15%, even more preferably at least 20%, or at least 25%, or at least 30% less than the first thickness of the sidewall.

[0020] The second thickness measured at the lower edge can correspond to the thickness of the sidewall at the lowest point of the sidewall.

[0021] The first thickness of the sidewall, measured in a direction perpendicular to the surface of the sidewall, may correspond to the thickness of the sidewall at a location adjacent to the upper wall, and / or to the thickness of the sidewall at a location between the upper and lower edges, particularly at a location within the range of 25% to 75% between the upper and lower edges, and / or to the average thickness of the sidewall.

[0022] The second thickness of the sidewall, measured at the lower edge, is measured in the same direction as the first thickness of the sidewall, or in a direction that deviates from the first thickness of the sidewall by less than 45 degrees, less than 25 degrees, or less than 10 degrees.

[0023] The second thickness of the sidewall, measured at the lower edge, is measured in a direction extending substantially parallel to the surface of the upper wall and / or the bottom surface of the substrate, or in a direction deviating from that direction by less than 45 degrees, less than 25 degrees, or less than 10 degrees.

[0024] In a preferred embodiment, the housing cover is configured in a hat shape such that the sidewalls integrally formed with the upper wall are configured as transverse circumferential walls having, in particular, four planar sidewalls.

[0025] At least one opening of the housing cover is arranged in the side wall or either side wall.

[0026] Preferably, the sidewall or any sidewall has multiple openings, preferably the number of openings corresponds to the number of lasers, and particularly preferably three openings are provided.

[0027] Each of the at least one opening, and in particular each of the plurality of openings, has a greater extent along the direction from the upper wall to the lower edge than along the direction extending perpendicular to that direction in the side wall.

[0028] Each of the at least one opening, or more particularly the plurality of openings, may have a particularly elliptical shape, the major axis of which runs along the direction from the upper wall to the lower edge.

[0029] The housing cover may include a transparent element assigned to at least one opening. This transparent element may, for example, have a bonding material applied to a sidewall including the at least one opening to hermetically seal the at least one opening. Preferably, the transparent element may be an integral component that hermetically seals each of a plurality of openings.

[0030] In a preferred embodiment, the transparent element is fixed to the outside of the housing cover, particularly to the outside of the sidewall or any sidewall, especially the sidewall that includes the at least one opening, and especially the sidewall to which a connecting material (e.g., welding material, such as glass solder) is applied.

[0031] The transparent element is preferably fixed at an angle relative to the surface of the sidewall, especially such that the transparent element has a greater distance from the lower edge of the sidewall to the upper edge of the sidewall than to the upper edge of the sidewall.

[0032] Here, the emitted light that is reflected back to one or more lasers at the transparent element can be suppressed very effectively.

[0033] Preferably, the transparent element can be fixed at its lower edge to a protrusion formed on the outer side of the sidewall, and in particular, can be tilted relative to the surface of the sidewall.

[0034] In a preferred embodiment, the upper wall of the housing cover has a thickness, measured in a direction perpendicular to its surface, that is less than the first thickness of the sidewall, particularly at least 10%, 20%, or 30% less than the first thickness of the sidewall.

[0035] Advantageously, this allows for weight reduction and / or enables lightweight design.

[0036] The upper wall of the housing cover may also have a thickness less than the second thickness of the sidewall, measured in a direction perpendicular to its surface, particularly at least 10%, at least 20%, or at least 30% less than the second thickness of the sidewall.

[0037] The upper wall and the sidewalls integrally formed with the upper wall may be metal or made of metal.

[0038] The substrate may include or be composed of ceramic, or may include or be composed of metal.

[0039] Transparent elements may include, or may be composed of, glass or sapphire, and / or may have an optical protective layer, particularly an anti-reflective coating.

[0040] The present invention also relates to a housing cover for a multi-laser device, particularly for a housing cover for a multi-laser device as described above. The housing cover according to the invention may include, in particular, one or more of the features described above in conjunction with the multi-laser device.

[0041] Furthermore, the present invention relates to a method for manufacturing a housing cover, particularly a method for manufacturing a housing cover as described above, and especially a method for manufacturing a housing cover as described above in conjunction with a multi-laser device.

[0042] The method according to the invention includes: providing a flat raw material, which in particular comprises or is composed of metal; preferably introducing one or more openings, in particular circular openings, into the flat raw material; drawing the flat raw material in such a way as to obtain a housing cover having an upper wall and sidewalls integrally formed with the upper wall, in particular such that one or more openings are arranged in elliptical openings in the sidewalls and / or such that the upper wall has a smaller thickness compared to the sidewalls; trimming the sidewalls at the lower edge in such a way that the sidewalls have a first thickness measured in a direction perpendicular to their surface, and a second thickness at the lower edge, in particular in the same direction, which is less than or equal to the first thickness; and preferably fixing a transparent element, preferably with a connecting material, to the sidewall containing at least one opening in order to hermetically seal the opening, in particular such that the transparent element is inclined relative to the surface of the sidewall.

[0043] Finally, the present invention relates to a device comprising a multi-laser apparatus, particularly an RGB laser module as described above. In particular, the present invention relates to the following devices.

[0044] The present invention relates in particular to head-mounted displays, especially AR glasses or eyeglasses, including a multi-laser device and / or housing cover as described above.

[0045] The present invention also relates to a head-up display comprising a multi-laser device and / or a housing cover as described above.

[0046] The present invention also relates to a motorcycle helmet including a head-up display according to the above description.

[0047] The present invention also relates to a projector comprising a multi-laser device and / or a housing cover as described above.

[0048] Finally, the present invention also relates to a projector for a mobile device, which includes a multi-laser device and / or a housing cover as described above.

[0049] German patent application No. 10 2020 110 658.0 and German utility model application No. 20 2021102 072.5, which have priority, are incorporated herein by reference and are therefore fully included in the disclosure of this application as if they were contained herein. Where a matching reference exists, the features of the patent documents incorporated herein correspond specifically to the features within the scope of this application.

[0050] In particular, a multi-laser device can therefore include:

[0051] The casing has

[0052] housing cover,

[0053] It has at least one opening constructed on it.

[0054] The opening has a transparent element assigned to it.

[0055] For the passage of electromagnetic radiation

[0056] substrate,

[0057] in,

[0058] The first laser emits, particularly in the red spectral range of the visible spectrum.

[0059] The second laser emits, particularly in the green spectral range of the visible spectrum, and

[0060] Preferably, a third laser emits, particularly in the blue spectral range of the visible spectrum.

[0061] Arranged within the housing, wherein,

[0062] The power supply leads pass through the housing and are guided to the corresponding laser, and

[0063] During laser operation, the majority of the emitted light passes through a transparent element.

[0064] Each laser is respectively

[0065] i) Preferably arranged on a platform,

[0066] ii) Arranged at a distance from the bottom surface of the substrate, and

[0067] iii) The lasers are aligned with each other, wherein,

[0068] The main direction of laser emission is basically parallel to the substrate of the shell.

[0069] The platform allows for a very clear arrangement of the lasers within the housing and optimizes the housing geometry, particularly reducing the housing size, while enabling the primary portion of the laser emission to be used as usable light. The primary portion of the laser light is intended to mean that more than 80%, preferably more than 85%, and most preferably more than 90% of the light emitted by each laser is emitted through its end face in the direction of the transparent element.

[0070] In addition, the platform may include materials with heat capacity and specific thermal conductivity that are also limited by its size, which allows individual lasers to be targeted for heat dissipation during their operation, that is, they are targeted for heat absorption while dissipating that heat to the outside of the housing.

[0071] The advantage of this multi-laser device also lies in the independent electronic actuation of each laser, especially in the case of the substrate, where, depending on the color or intensity represented, i.e. the brightness or chromaticity of the image signal that may be represented, not all lasers emit simultaneously; they may even remain completely silent during blank or dark phases. Moreover, there is only slight optical interaction between the individual lasers within the housing, so even with relatively high emission, i.e., one laser emitting at its full electrical range, it will not optically interact with another corresponding laser, especially when the latter emits, for example, at a much lower intensity.

[0072] For example, compared to semiconductor devices that emit light perpendicular to the substrate, RGB laser modules have the advantage of better integrability, especially in applications where only a small space is available, because the substrate can then be configured as a support component, for example, to receive additional optical components, especially those that are tuned to the light emitted by the laser.

[0073] Generally, within the scope of this disclosure, the blue spectral range is defined as a wavelength range from 450 nm to 490 nm, the green spectral range is a wavelength range from greater than 490 nm to 560 nm, and the red spectral range is a wavelength range from 630 nm to 700 nm. Therefore, the multi-laser device disclosed herein can provide a color space that is beneficial for the representation of visual signals.

[0074] Alternatively, more than one laser or all lasers can emit light within the same spectral range, which is advantageous, for example, when a multi-laser device is used for illumination purposes.

[0075] Within the scope of this disclosure, the principal direction of laser emission refers to the optical axis of the laser emitted by each laser, or at least the direction of propagation of the maximum intensity with respect to the maximum value of the transverse intensity distribution of the emitted laser, and thus the axial translation direction of the maximum transverse intensity.

[0076] Within the scope of this disclosure, for the sake of brevity, the term main emission direction will also be used as a synonym for the main direction of laser emission.

[0077] The statement that the main direction of laser emission is substantially parallel to the substrate of the housing means that the main direction of laser emission rises no more than 5° from the plane defined by the lower surface of the substrate or base plate 4, or slopes no more than 5° below it.

[0078] A particularly advantageous arrangement is achieved when the housing cover comprises or is composed of metal, the substrate comprises or is composed of metal, and the housing cover is connected to the substrate by welding.

[0079] In this context, the term "includes metal" is intended to mean, for example, that the metallic body may be partially or completely covered with a non-metallic coating, such as an oxide layer or varnish, especially a highly absorbent matte varnish.

[0080] Attaching the housing cover to the substrate by welding or fusion can provide significant advantages for the long-term operational durability of multi-laser devices, as this allows for a fluid-tight and hermetic-tight connection between the housing cover and the substrate, corresponding to, for example, standard MIL-STD 883, method 1014.

[0081] Typically, when such a housing (e.g., a housing cover) is welded to a preferably metal-coated ceramic substrate, a flux such as formic acid is used in an atmosphere containing nitrogen or hydrogen. The residue of this flux then remains in the housing. Even in trace amounts, these residues can interact with and damage the semiconductor material of a semiconductor laser that emits in the blue spectrum.

[0082] However, this is not the case in the embodiments described herein, where, for example, the transparent element can first be fixed to the housing cover by a soldering process, and the soldering to the substrate can be performed subsequently, especially after cleaning the housing cover. This ensures that the H2O content in the atmosphere within the housing is less than 5000 ppm, and that, due to the airtight configuration of the housing, the permissible moisture pressure will not be exceeded throughout the entire service life of the component, corresponding to standard MIL 883, method 1018.

[0083] If the platform and substrate are constructed as a single unit, this has advantages in terms of manufacturing technology, as a substrate of the appropriate shape can be economically provided through material removal surface treatment or imprinting processes.

[0084] However, if the substrate comprises or is composed of metal, such as cold-rolled steel CRS1010, and the platform is composed of or comprises a material different from that of the substrate, particularly oxygen-free high thermal conductivity copper (OFHC), and the platform is preferably pressed, brazed, or welded to the substrate, then a platform with a defined advantageous specific thermal conductivity can be provided, the heat capacity of which is determined by its design dimensions, its specific heat capacity, and its material selection. This enables efficient temperature management by controlling the heat dissipation of each laser.

[0085] In this case, the above material specifications are given only as examples, and other metals such as aluminum, steel, or stainless steel, as well as austenitic and ferritic stainless steels, can be used instead, provided they remain within a rust-free range when carrying out the invention. Furthermore, titanium and Monel alloys with a high proportion of copper, or sealing alloys including NiFe alloys or NiFeCo alloys, can also be used in principle.

[0086] In other advantageous embodiments, a fast-axis-collimating-linse (FAC) lens is arranged on a platform, preferably spaced apart from the end face of the laser, in order to achieve beam shaping with maximum efficiency and low intensity loss by masking the diverging beam of the emitted laser.

[0087] Particularly preferably, the transparent element may comprise or be composed of glass. In this case, the glass of the transparent element may, for example, comprise quartz glass or borosilicate glass. Furthermore, the transparent element may also be composed of or comprise sapphire, especially in each case as a crystalline material.

[0088] However, in general, when measured in the direction of radiation emitted by the laser, the transmittance of the transparent element in the spectral range of 250 to 2000 nm is greater than 80%, and particularly preferably greater than 90%.

[0089] In the context of this disclosure, the terms “light emitted by a laser” and “radiation emitted by a laser” should be understood in the same sense and used as synonyms.

[0090] In another configuration, the transparent element can be constructed as a FAC lens (fast-axis collimating lens) or may include an FAC lens (fast-axis collimating lens), especially an FAC lens used thereon.

[0091] Alternatively, the transparent element can be constructed as a fiberboard or include a fiberboard.

[0092] In a preferred embodiment, the transparent element is held on the housing cover by glass solder, or held on a frame arranged on the housing cover by glass solder.

[0093] In other preferred embodiments, in order to have a smaller size than the aforementioned embodiments in which the transparent element is attached to the housing cover using glass solder, the transparent element can be held on the housing cover by metal solder, preferably AuSn solder.

[0094] Another configuration includes a transparent element welded to the housing cover.

[0095] If the wall of the housing cover, where at least the transparent element is arranged, is tilted relative to the substrate, and the tilt angle of this wall relative to the normal direction of the bottom surface of the substrate is in the range of 35° to 60°, preferably in the range of 40° to 50°, and particularly preferably in the range of 43° to 48°, this can very effectively suppress the back reflection of light emitted at the transparent element into one or more lasers. These designs generally avoid the need for anti-reflective coatings on the transparent element without adversely affecting the function of multi-laser devices due to reflected or scattered light.

[0096] The aforementioned tilt angle α is preferably selected to intentionally generate a reverse reflection, which is used to measure the laser power by a monitoring photodiode, also referred to herein as a monitoring diode.

[0097] However, in order to suppress light from being directly reflected back into the laser resonators of the individual lasers in the RGB laser module, even smaller angles, such as the typical range of 7° to 15°, are sufficient.

[0098] A significant advantage is that the monitoring diode can also be positioned below the transparent element, and the laser light reflected back from the transparent element can act on the monitoring diode, thereby obtaining a sensing signal of the light intensity emitted by the corresponding laser assigned to the monitoring diode. This allows for fast and efficient feedback signals, enabling precise and controllable driving of multi-laser devices.

[0099] In this context, the following terminology is intended to be understood relative to the substrate and the housing cover. Extending perpendicularly from the substrate, and therefore in the normal direction, and in the direction of the housing cover, should be understood as upward. Thus, in this direction, there may be an object above, below, or at the same height as another object (in this direction). Regarding the Cartesian coordinate system described below, upward also refers to its positive Z direction.

[0100] Alternatively or additionally, monitoring diodes may be arranged after the laser, particularly on the carrier assigned to it, wherein preferably each laser is assigned at least one of its own monitoring diodes, in which case the carrier may have a conductive coating as the power supply lead for its respective monitoring diode.

[0101] In the context of this disclosure, the light-emitting surface of a laser facing the transparent element is defined as the front side, and the propagation direction of the laser passing through this light-emitting surface is defined as "forward direction" emission or "forward direction" transmission. A description of the arrangement behind the laser defines a position in front of another light-emitting surface of the laser, located on a side opposite to the transparent element.

[0102] Preferably, in this case, the monitoring diode can be arranged on a carrier preferably comprising or composed of ceramic, and the normal direction of the surface of the carrier on which the monitoring diode is arranged can be configured to be tilted relative to the main emission direction of at least one laser, the tilt being in the range of 3° to 15°, preferably in the range of 5° to 10°, and particularly preferably in the range of 6° to 8° relative to the main emission direction. In this way, light emitted from the back of the laser is very effectively reflected by the monitoring diode, so that it no longer re-enters one of the lasers, thus preventing undesirable optical interactions, such as mode coupling of the resonator modes of the individual lasers.

[0103] In another preferred embodiment, the normal direction of the wall of the housing cover, where at least the transparent element is arranged, is configured to be inclined relative to the main emission direction of at least one laser, the inclination being within an angle range of 3° to 15°, preferably within an angle range of 5° to 10°, and particularly preferably within an angle range of 6° to 8° relative to the main emission direction. In this way, light emitted from the front side of the laser is very effectively reflected by the surface of the transparent element, so that it no longer re-enters one of the lasers, thus preventing undesirable optical interactions, such as coupling of the resonator modes of the individual lasers.

[0104] In an alternative configuration, the housing cover may include multiple openings, wherein a transparent element is assigned to one of these openings individually, or a single transparent element is assigned to all of these openings for sharing.

[0105] In another advantageous configuration, the housing cover includes a plurality of openings forming transparent elements of beam-forming optics, selected from a group of optics respectively arranged in one of the openings:

[0106] Spherical plano-convex or concave-convex lenses,

[0107] Spherical or hemispherical lenses,

[0108] Aspherical plano-convex or concave-convex lenses.

[0109] In this way, multi-laser devices can be very compact and, due to their precise dimensions, even integrated into external optical systems when optical pre-adjustment is necessary—that is, the axial and lateral positions of the optical elements have already been adjusted. In this manner, the substrate of the multi-laser device can be inserted, if necessary, into a precisely positioned pre-formed recess in another optical system, and accommodated while the substrate has already been adjusted relative to the other optical system through this positioning. Through contact between the substrate and the other optical system, heat can be further dissipated from the multi-laser device in a defined manner, and additional heat dissipation of the lasers in the multi-laser device can be performed by the other optical system.

[0110] Further design freedom is provided if the optical fiber is connected to the housing, especially the housing cover, preferably by means of a fiber connector, especially a releasable fiber connector or a permanently connected fiber connector, because the multi-laser device can be arranged, for example, in such a way that it is spaced apart from another optical system, which will be explained in more detail below by way of the example of another optical system provided by AR glasses.

[0111] When optical fibers are distributed to each laser in a multi-laser device, and the fibers distributed to the lasers are bundled together, in which their respective cores are preferably close to each other and preferably form a common fiber cladding surrounding the cores, this can further contribute to the design compactness of a system consisting of a multi-laser device and other optical systems. When, for example, these optical fibers are arranged adjacent to each other in a plane extending in the row direction of a designated imaging mechanism, for example in the case of another designated optical mechanism having a line-by-line image structure, the superposition of the light components of the first laser emitted in the red spectral range of the visible spectrum, the light components of the second laser emitted in the green spectral range of the visible spectrum, and the light components of the third laser emitted in the blue spectral range of the visible spectrum, occurring in the row direction, may have already conveyed the impression of white to the human eye, provided that these corresponding color components superimpose so rapidly in their respective rows that the human eye can no longer distinguish the color change. In this way, fiber splicing processes that could potentially extend the length can be avoided, and the individual optical fibers of this embodiment can be configured to be very short.

[0112] Within the scope of this disclosure, the terms fiber, optical fiber, and optical guide fiber are used respectively to describe fibers suitable for guiding light from blue, green, and red emitting lasers across the entire spectral range of laser emission and suitable for transmitting it from its inlet to its outlet with low loss. Such fibers are known to those skilled in the art and require no further explanation.

[0113] Advantageously, multi-laser devices may include glass-metal feedthroughs for providing leads to the lasers and / or monitoring diodes.

[0114] If the monitoring diodes each have color filters, especially bandpass filters configured for the emission wavelength of their respective assigned lasers, the light from the other individual lasers can be suppressed, and a better signal-to-interference ratio or a better signal-to-noise ratio can be obtained for the sensing signals of the monitoring diodes.

[0115] When the substrate of the housing is configured to a reference potential and carry current, the electrical wiring of multi-laser devices can be simplified, and a housing with reliable operation can be provided to the user.

[0116] In another advantageous configuration, the substrate can be configured as an optical component carrier, particularly an optical component carrier that structurally protrudes below the housing cover.

[0117] To suppress stray light, the inside of the housing cover can be constructed to be black, especially matte black, where paint or coatings can be used, such as black chrome plating or zinc-nickel coatings, particularly as electrolytic coatings. In this way, 98% or more of the light irradiated onto the surface within the spectral range of the light emitted by the laser can be absorbed by the surface coated in this manner.

[0118] Advantageously, the housing may have a protective mechanism for the glass of the transparent element, which is specifically configured to protrude beyond the portion of the transparent element in the lateral direction.

[0119] For example, if the housing dimensions are: (especially the height in the X direction is 1.0 mm to 3.5 mm and / or the width in the Y direction is 4 mm to 10 mm and / or the length in the Z direction is 4 mm to 10 mm), then a multi-laser device with an attractive design can be used in a variety of applications, especially mobile applications.

[0120] The directions mentioned above, especially the X, Y, and Z directions, will be further explained within the scope of the following detailed descriptions, especially referring to... Figure 1 The Cartesian coordinate system shown will be further explained.

[0121] These mobile applications may, for example, involve AR glasses or eyewear that include such multi-laser devices, or head-up displays used for, for example, helmet goggles, protective helmets such as motorcycle helmets, or helmets used by police or security forces, or for devices or institutions in avionics equipment.

[0122] Projectors can also benefit from the multi-laser devices disclosed here and their very small size, especially when used in mobile devices. Attached Figure Description

[0123] The present invention will now be described in more detail with reference to the accompanying drawings and preferred embodiments.

[0124] In the diagram:

[0125] Figure 1 A perspective view of a multi-laser device for comparison is shown.

[0126] Figure 2 Two perspective views of a housing cover for a multi-laser device according to the present invention are shown.

[0127] Figure 3 Cross-sectional views of the multi-laser devices used for comparison are shown.

[0128] Figure 4 A cross-sectional view of a multi-laser device according to the present invention is shown.

[0129] Figure 5 A cross-sectional view of another multi-laser device according to the present invention is shown.

[0130] Figure 6 A cross-sectional view of the lower edge of the sidewall is shown.

[0131] Figure 7 A cross-sectional view of another multi-laser device according to the present invention is shown.

[0132] Figure 8 A cross-sectional view of the lower edge of the sidewall with connecting material is shown.

[0133] Figure 9 A cross-sectional view of the lower edge of the sidewall with connecting material is shown.

[0134] Figure 10 A cross-sectional view of another multi-laser device according to the present invention is shown.

[0135] Figure 11 A cross-sectional view of another multi-laser device according to the present invention is shown.

[0136] Figure 12 A cross-sectional view of the sidewall, including the opening with a transparent element, is shown.

[0137] Figure 13 A cross-sectional view of another multi-laser device according to the present invention is shown.

[0138] Figure 14 A perspective view of another housing cover for a multi-laser device according to the present invention is shown. Detailed Implementation

[0139] In the following description of preferred embodiments, the same reference numerals denote the same or having the same effect. This also applies to German patent application No. 10 2020 110 658.0 and German utility model application No. 202021 102 072.5.

[0140] For comparison, Figure 1 A multi-laser device 1 with a housing 2 is shown, the housing 2 including a housing cover 3, which is fluidly and hermetically held on a substrate 4.

[0141] Weld S ( Figure 1 (Not shown) Located between the housing cover 3 and the base plate 4, the weld seam substantially spans the lateral protrusion A of the housing cover 3 located between the housing cover 3 and the base plate 4.s Extending over the entire contact area below, this lateral protrusion forms the welding flange.

[0142] In the disclosure of this invention, when He is filled under a pressure difference of 1 bar, the leakage rate of an object, such as the housing of a multi-laser device, is less than 1 × 10⁻⁶ at room temperature. -3 If the value is millibars per second, the object is considered to be either airtight or fluid-tight.

[0143] However, preferably, when He is filled under a pressure difference of 1 bar, 1×10⁻⁶ is achieved. -8 The leakage rate is measured in millibars per second. However, since the required seal value may depend on the internal volume of the housing, the seal achieved in the current case ensures that the partial pressure of water in the housing of the multi-laser unit does not exceed 5000 ppm throughout the entire service life of the component.

[0144] Platform 5 ( Figure 1 (Not shown in the image) is arranged on substrate 4, or is constructed from substrate 4 itself.

[0145] In a preferred embodiment, a first laser 6 (emitted in the red spectral range of the visible spectrum) Figure 1 (Not shown in the image) A second laser 7 emitting in the green spectral range of the visible spectrum. Figure 1 (not shown in the image) and a third laser 8 emitting in the blue spectral range of the visible spectrum. Figure 1 (Not shown) is arranged inside the housing 2.

[0146] Each of the lasers 6, 7, and 8 is arranged and positioned on platform 5 such that each of these lasers 6, 7, and 8 has a defined distance relative to the bottom surface 9 of substrate 4. The bottom surface 9 of the substrate refers to its underside.

[0147] The light emitting surfaces 10, 11, and 12 on the front side of lasers 6, 7, and 8 Figure 1 Before (not shown), an opening 13 is constructed in the housing cover 3, and a transparent element 14 is placed in the opening 13.

[0148] In a preferred embodiment, the transparent element 14 is held on the housing cover 3, for example, by means of glass solder.

[0149] In an alternative configuration, the transparent element 14 is held on the housing cover 3 itself by gold solder, for example by AuSn solder.

[0150] The use of gold solder allows the window 14 to be directly mounted on the housing cover 3, and the design dimensions of the transparent element 14 and the housing cover 3 are not very strict.

[0151] Figure 2Two housing covers 3 according to the invention are shown for a multi-laser device 1. Each housing cover 3 has three separate, particularly circular, openings 13, each for any one of the three lasers 6, 7 and 8.

[0152] The housing cover 3 also includes a transparent element 14, which is hermetically connected to the side wall of the housing cover 3, including the opening 13, by means of a connecting material, particularly glass solder and / or metal solder.

[0153] The housing cover 3 with an integrated optical window is particularly suitable for the hermetic packaging of RGB lasers. Therefore, the housing cover 3 can also be referred to as the RGB cover.

[0154] Figure 2 The embodiment shown on the left is a housing cover 3 (RGB cover) that can be manufactured or produced using turning and milling techniques. This production method may be particularly advantageous considering delivery time, cost, and / or design flexibility.

[0155] Accordingly, the housing cover 3 has a milled metal housing in which concentric openings 13 (emitter openings) are introduced. A transparent element 14 forms an optical window and may be made of sapphire or glass. Furthermore, an anti-reflective coating may be provided to increase transmittance. This minimizes radiation loss. The optical window is hermetically sealed to the metal housing using a welding process (with solder made of, for example, glass solder or metal solder).

[0156] Figure 2 The embodiment shown on the right is a housing cover 3 (RGB cover) that can be produced or manufactured using a deep drawing process. This production method may be advantageous for economic reasons and further provides product benefits, which will be described in more detail below.

[0157] Accordingly, the housing cover 3 has a drawn metal housing in which concentric openings 13 (emitter openings) are introduced. A transparent element 14 forms an optical window and may also be made of sapphire or glass. Similarly, an anti-reflective coating may be provided to increase transmittance, thereby minimizing radiation loss. The optical window is hermetically sealed to the metal housing by means of a welding process (using solder made of, for example, glass solder or metal solder).

[0158] The housing cover 3 in particular has an upper wall 100 and a side wall 200. The side wall 200 is integrally formed with the upper wall 100 and is configured to extend around the z-axis in this example. In this example, the side wall 200 is configured as a wall body extending laterally with four planar side walls. There is a circular edge 101 between the upper wall 100 and the side wall 200. Preferably, there can also be a circular edge 204 between the planar side walls. The circular edge 101 or 204 can be characterized by the outer diameter on the outside of the housing cover 3 and / or the inner diameter on the inside of the housing cover 3. The inner diameter can, for example, correspond to the thickness d1 or be in the range from half of the thickness d1 to twice the thickness d1.

[0159] For comparison, Figure 3 a multi-laser device 1 with a housing 2 is shown, the housing 2 having a housing cover 3 hermetically fixed to a substrate 4, where a platform is arranged on the substrate 4, on which a first laser 6, a second laser 7 and a third laser 8 are arranged ( Figure 3 the second and third lasers are not shown in the figure).

[0160] The shown housing cover 3 has a lateral projection A s or a laterally protruding flange. However, this projection A s or flange will limit the construction space and / or the lateral extent of the housing 2 as well as the position height of the transparent element 14 or the emitter opening 13.

[0161] Figure 4 A multi-laser device 1 is shown, in which the metal body of the housing cover 3 is produced or can be produced by a deep drawing process. An additional process step of trimming any flanges can be provided, which contributes to the desired shaping.

[0162] The housing cover 3 of the multi-laser device 1 advantageously has smaller dimensions than Figure 3 the comparative example shown in the figure: H1 < H2, L1 < L2 and / or P1 < P2, where this advantage has a particularly pronounced and beneficial effect in the case of the smaller dimension L1 < L2. However, trimming the flange can also contribute to reducing the dimensions, H1 < H2 or P1 < P2.

[0163] The housing cover 3 has an upper wall 100 and a side wall 200 integrally constructed with the upper wall 100, the side wall ending at a lower edge 201 fixed to the substrate 4. The lower edge 201 is fixed to the substrate 4 with a connecting material 300.

[0164] The side wall has a first thickness d1 measured in a direction perpendicular to its surface, and a second thickness d2 measured at the lower edge 201, particularly in the same direction, the second thickness d2 being less than or equal to (equal in this case) the first thickness d1.

[0165] As described above, the housing cover 3 may typically have one or more circular edges 101 or 204 (not shown in the cross-sectional view).

[0166] Figure 5 A multi-laser device 1 with a housing cover 3 is shown, wherein the sidewall 200 has an outwardly curved surface 202 at the lower edge 201 inside the housing cover 3, such that the second thickness d2 is less than the first thickness d1, and the thickness of the sidewall gradually decreases toward the lowest position of the sidewall.

[0167] The connecting material 300 extends in a region that is shorter than the first thickness d1 or the second thickness d2 in the direction along the first thickness d1 or corresponding second thickness d2 of the sidewall.

[0168] In particular, because a deep-drawing process is used during production, an outwardly stretched radius is created on the inner side of the bottom of the cover. For subsequent applications (soldering to substrate 4), the gradually thinning wall thickness of the bottom of the cover is especially advantageous, allowing the connecting material to extend along the reduced width (reduced width of spare parts, such as pads or metallization on the substrate). This facilitates component miniaturization or increases the construction space within the housing.

[0169] Figure 6 The lower edge 201 of the sidewall 200 of the housing cover 3 is shown, wherein the surface 202 that curves outward on the inner side of the housing cover 3 is curved according to a radius R. The housing cover 3 also has a second thickness d2 at the lower edge 201, which is less than the first thickness d1.

[0170] Furthermore, the sidewall 200 has a protrusion 203 at its outer lower edge 201, which is smaller than the first thickness d1, and in particular smaller than one-fifth of the first thickness d1. The protrusion 203 is also smaller than the second thickness d2.

[0171] Figure 7 A multi-laser device 1 with a housing cover 3 is shown, wherein the lower edge 201 of the sidewall 200 is fixed to the substrate 4 in such a way that a connecting material 301 is introduced between the outwardly curved surface 202 inside the housing cover and the substrate 4. In this case, the connecting materials 300 and 301 are continuous connecting materials, wherein the connecting material 301 disposed on the curved surface 202 protrudes from the substrate above the connecting material 300 between the lower edge 201 of the sidewall 200 and the substrate 4.

[0172] In particular, because a deep-drawing process is used in the manufacturing process, an outwardly stretched radius can be formed on the inner side of the bottom of the cover. This provides the following advantages for subsequent applications (soldering to the substrate): the radius formed on the inner side of the wall increases the effective welding area of ​​the cover (especially the metal part), and allows the connecting material (especially solder) to form a larger meniscus angle. Furthermore, with equal width of the connecting material (pad width), a larger volume of material (especially solder volume) can be applied. These three points contribute to a more stable connection (especially solder joint), thus making the product more durable.

[0173] Figure 8 The lower edge 201 of the sidewall 200 of the housing cover 3 is shown, having a protrusion 20 less than the first thickness d1, especially less than one-fifth of the first thickness d1, and uniform connecting materials 300, 301 disposed on the lower edge 201, wherein the portion 301 of the connecting material attached to the curved surface 202 protrudes higher.

[0174] Figure 9 Another embodiment is shown, illustrating the lower edge 201 of the sidewall 200 of the housing cover 3, wherein on the substrate 4 ( Figure 9 A connecting material 303 is provided between the sidewall 200 (not shown) and the sidewall, and this connecting material is disposed on the outer side of the sidewall 200, for example on the protrusion. Therefore, the connecting material 300 can form a solder meniscus on the outer side of the housing cover 3. The connecting material 303 adjacent to the outer side of the sidewall 200 is preferably additionally present between the lower edge 201 of the sidewall 200 and the substrate 4, protruding higher from the substrate. Preferably, as described above, the adjacent connecting material 301 can also be disposed on the inner side of the sidewall 200. The connecting material 303 and the connecting material 300 and / or 301, which may be present, are preferably continuous connecting materials. Generally, by means of a smaller thickness d2 at the lower edge compared to the thickness D1, especially by narrowing and / or rounding, it is advantageous to achieve narrower connecting material beads (especially solder beads). Thus, it achieves particular dimensional advantages compared to parts with sharp edges and / or parts with flanges (with or without solder meniscus).

[0175] Figure 10 A multi-laser device 1 with a housing cover 3 is shown, the housing cover 3 having an outwardly curved surface 202 at the lower edge 201 on the inner side of the housing cover 3, such that the second thickness d2 is less than the first thickness d1, and the thickness of the sidewall gradually decreases towards the lowest position of the sidewall.

[0176] In this case, the outwardly curved surface 202 serves as a guiding aid when joining the housing cover 3 to the substrate 4. Correspondingly, the substrate 4 can be at least partially inserted into the housing cover 3, thereby further minimizing the height of the assembly. For this purpose, the substrate 4 can have laterally curved end sides which can be connected by means of a connecting material to the curved surface 202 of the side wall 200 of the housing cover 3 (not shown in Figure 9 ).

[0177] In particular, since a deep-drawing process is used during production, a radius which projects outwards can be formed on the inside of the bottom of the cover. This provides particular advantages for subsequent applications: namely, that the radius formed on the inside of the wall can be used as an improved guiding aid when joining the cover to the substrate. This can additionally reduce the length and width of the overall package, in particular H1 < H2 and L1 < L2.

[0178] Figure 11 The multi-laser device 1 with the housing cover 3 is shown, which housing cover has a projection 203 at the lower edge 201 on the outside of the side wall 200. The transparent element 14, which is fixed on the outside of the housing cover 3 particularly by means of a connecting material 302, is fixed on the projection 203 at the lower edge 201 such that the transparent element 14 is inclined with respect to the surface of the side wall 200.

[0179] In particular, since a deep-drawing process is used during production, in addition to the inner radius, a projection 203 can also be produced on the outside of the housing cover 3 or the metal housing. A particular advantage of such a projection is that the window to which it is fixed (welded) is slightly inclined. Generally speaking, when using lasers (in particular EELs), it is necessary to prevent a part of the emitted laser radiation 400 from being reflected back into the laser cavity. Due to the inclination of the transparent element 14, the part of the reflected light 401 is deflected to a non-critical position inside the housing 2.

[0180] Figure 12 The multi-laser device 1 is shown, in which the transparent element is fixed around the opening 13 by means of a connecting material 302 (in particular solder, such as glass solder and / or metal solder) on the side wall 200 of the housing cover 3.

[0181] Figure 13 The multi-laser device 1 is shown, in which the upper wall 100 of the housing cover 3 has a thickness d3 which is smaller than the first thickness d1 of the side wall. One advantage of this is that the weight is reduced and / or a lightweight design is achieved.

[0182] Different wall thicknesses can be achieved, for example, by pre-embossing the raw material (for example a metal strip) before the deep-drawing process.

[0183] Figure 14A housing cover 3 with an opening 13 is shown, which extends in a direction (z-direction) from the upper wall 100 to the lower edge 201 of the side wall 200 than in a direction (y-direction) extending perpendicular to that direction in the side wall. In a particular example, the opening 13 is elliptical. This has the particular advantage of accommodating elliptical laser beam profiles, thus making its dimension smaller in the y-direction. In particular, the beam profile of an EEL laser typically has elliptical characteristics. Another advantage is improved mechanical stability of the housing cover 3.

[0184] In particular, if raw materials with introductory openings (such as pre-stamped strips) are used in the cap production process, elliptical openings can be formed through subsequent deep drawing processes. Another advantage in this case is less tool wear, or a longer tool life (tool life, less waste during stamping), because less material needs to be removed compared to concentric openings. Furthermore, caps with smaller heights can be produced using pre-stamped strips due to process limitations.

[0185] Those skilled in the art will understand that the above features and / or advantages can be implemented individually or in combination.

Claims

1. A multi-laser device (1), comprising: a housing (2) having a base plate (4) and a housing cover (3) fixed on the base plate (4), wherein the housing cover (3) comprises at least one opening (13) for the passage of electromagnetic radiation, the opening having a transparent element (14) assigned to the opening, a plurality of lasers, each laser being arranged within the housing (2) spaced apart from a bottom face (9) of the base plate (4), wherein the housing cover (3) of the housing (2) comprises an upper wall (100) and a side wall (200) which is integrally configured with the upper wall, the side wall ending in a lower edge (201) which is fixed on the base plate (4), and wherein the side wall (200) has a first thickness (dl) measured in a direction perpendicular to its surface, and a second thickness (d2) measured at the lower edge (201), the second thickness being smaller than the first thickness (dl), wherein the second thickness (d2) measured at the lower edge (201) corresponds to the thickness of the side wall (200) at its lowest position, the housing cover (3) having a drawn metal housing, the side wall (200) being curved according to a radius R on the inside at the lower edge (201). The multi-laser device is an RGB laser module having a first laser (6) emitting in the red spectral range, a second laser (7) emitting in the green spectral range and a third laser (8) emitting in the blue spectral range. Each laser is arranged on a platform (5). wherein 4. The multi-laser device according to any one of the preceding claims 1 to 3, the side wall having an outwardly curved surface (202) at the lower edge on the inside of the housing cover, such that the thickness of the side wall gradually decreases towards the lowest position of the side wall, and / or wherein the side wall is configured without a protrusion at the lower edge on the outside. The side wall has a protrusion (203) which is smaller than the first thickness. The side wall has a protrusion (203) which is smaller than half of the first thickness.

2. The multi-laser apparatus of claim 1, wherein, The side wall has a protrusion (203) which is smaller than a quarter of the first thickness.

3. The multi-laser apparatus of claim 1, wherein, 8. The multi-laser device according to any one of the preceding claims 1 to 3, the lower edge of the side wall being fixed on the base plate in such a way that a connecting material (300) is introduced between the lower edge of the side wall and the base plate in a region which is shorter in the direction of the first thickness or the second thickness of the side wall than the first thickness or the second thickness of the side wall. The lower edge of the side wall is fixed on the base plate in such a way that a connecting material (301) is introduced between the outwardly curved surface (202) on the inside of the housing cover and the base plate, such that the connecting material (301) protrudes higher from the base plate at the inside of the housing cover than between the lower edge of the side wall and the base plate. wherein ​ ​ 5. The multi-laser device according to any of the preceding claims 1 to 3, wherein, ​ 6. The multi-laser apparatus of any one of claims 1-3, wherein, ​ 7. The multi-laser apparatus of any one of claims 1-3, wherein, ​ ​ wherein ​ 9. The multi-laser apparatus of claim 4, wherein, ​ 10. The multi-laser device of any of the preceding claims 1 to 3, wherein, The lower edge of the sidewall is fixed on the base plate in such a way that a connecting material (303) is introduced between the outside of the sidewall and the base plate, so that the connecting material (301) protrudes higher from the base plate at the outside of the housing cover than between the lower edge of the sidewall and the base plate.

11. The multi-laser apparatus of claim 5, wherein, The lower edge of the sidewall is fixed on the base plate in such a way that a connecting material (303) is introduced between the protrusion (203) and the base plate, so that the connecting material (301) protrudes higher from the base plate at the outside of the housing cover than between the lower edge of the sidewall and the base plate.

12. Multi-laser device according to any of the preceding claims 1 to 3, wherein The sidewall is tapered at the lower edge, and / or wherein the second thickness of the sidewall, measured at the lower edge, is at least 5% smaller than the first thickness of the sidewall.

13. The multi-laser device of any of the preceding claims 1 to 3, wherein, The sidewall is tapered along a direction extending from the upper edge to the lower edge.

14. The multi-laser device of any of the preceding claims 1 to 3, wherein, The second thickness of the sidewall, measured at the lower edge, is at least 10% smaller than the first thickness of the sidewall.

15. The multi-laser device of any of the preceding claims 1 to 3, wherein, The second thickness of the sidewall, measured at the lower edge, is at least 15% smaller than the first thickness of the sidewall.

16. The multi-laser device of any of the preceding claims 1 to 3, wherein, The second thickness of the sidewall, measured at the lower edge, is at least 20% smaller than the first thickness of the sidewall.

17. The multi-laser device of any of the preceding claims 1 to 3, wherein, The second thickness of the sidewall, measured at the lower edge, is at least 25% smaller than the first thickness of the sidewall.

18. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The second thickness of the sidewall, measured at the lower edge, is at least 30% smaller than the first thickness of the sidewall.

19. Multi-laser device according to any of the preceding claims 1 to 3, wherein The first thickness of the sidewall, measured in a direction perpendicular to the surface of the sidewall, corresponds to the thickness of the sidewall at a position adjacent to the upper wall, to the thickness of the sidewall at a position between the upper wall and the lower edge, and / or to an average thickness of the sidewall.

20. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The first thickness of the sidewall, measured in a direction perpendicular to the surface of the sidewall, corresponds to the thickness of the sidewall at a position adjacent to the upper wall, to the thickness of the sidewall at a position between the upper wall and the lower edge, and / or to an average thickness of the sidewall.

21. Multi-laser device according to any of the preceding claims 1 to 3, wherein, The second thickness of the sidewall, measured at the lower edge, is measured in the same direction as the first thickness of the sidewall, or in a direction deviating less than 45 degrees, less than 25 degrees or less than 10 degrees from the direction of the first thickness of the sidewall, and / or wherein the second thickness of the sidewall, measured at the lower edge, is measured in a direction extending parallel to the surface of the upper wall and / or to the bottom surface of the base plate, or in a direction deviating less than 45 degrees, less than 25 degrees or less than 10 degrees from said direction.

22. Multi-laser device according to any of the preceding claims 1 to 3, wherein the side wall which is integrally configured with the upper wall is configured as a lateral circumferential wall body having four planar side walls, and / or wherein at least one opening of the housing cover is arranged in the side wall and any side wall, and / or wherein the side wall and any side wall are provided with a plurality of openings.

23. Multi-laser device according to any of the preceding claims 1 to 3, wherein the side wall which is integrally configured with the upper wall is configured as a lateral circumferential wall body having four planar side walls, and / or wherein the side wall and any side wall are provided with a plurality of openings, the number of which corresponds to the number of lasers.

24. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The side wall and any side wall are provided with three openings.

25. Multi-laser device according to any of the preceding claims 1 to 3, wherein each of the at least one opening has a greater extent in a direction from the upper wall to the lower edge than in a direction extending in the side wall perpendicular to this direction, and / or wherein each of the at least one opening has an elliptical shape, the major axis of which is in the direction from the upper wall to the lower edge.

26. Multi-laser device according to claim 22, wherein each of the plurality of openings has a greater extent in a direction from the upper wall to the lower edge than in a direction extending in the side wall perpendicular to this direction, and / or wherein each of the plurality of openings has an elliptical shape, the major axis of which is in the direction from the upper wall to the lower edge.

27. Multi-laser device according to any of the preceding claims 1 to 3, wherein the housing cover comprises the transparent element assigned to the at least one opening.

28. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The transparent element is provided with a connecting material on the side wall comprising the at least one opening in order to hermetically close the at least one opening.

29. The multi-laser apparatus of claim 22, wherein, The transparent element hermetically closes each of the plurality of openings as an integral component.

30. Multi-laser device according to any of the preceding claims 1 to 3, wherein, The transparent element is fixed with a connecting material on the outside of the housing cover.

31. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The transparent element is fixed on the outside of the side wall or any side wall.

32. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The transparent element is fixed on the outside of the side wall comprising the at least one opening.

33. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The transparent element is fixed inclined with respect to the surface of the side wall so that it has a greater distance from the side wall to the lower edge of the side wall.

34. The multi-laser apparatus of any of preceding claims 1 to 3, wherein, The transparent element is fixed at the lower edge on a protrusion configured on the outside of the side wall and thus inclined with respect to the surface of the side wall.

35. Multi-laser device according to any of the preceding claims 1 to 3, wherein the upper wall of the housing cover has a thickness which is less than a first thickness of the side wall measured in a direction perpendicular to its surface, and / or wherein the upper wall of the housing cover has a thickness which is less than a second thickness of the side wall measured in a direction perpendicular to its surface.

36. Multi-laser device according to any of the preceding claims 1 to 3, wherein the upper wall of the housing cover has a thickness, measured in a direction perpendicular to its surface, which is at least 10% less than a first thickness of the side wall, and / or the upper wall of the housing cover has a thickness, measured in a direction perpendicular to its surface, which is at least 10% less than a second thickness of the side wall.

37. The multi-laser device according to any of the preceding claims 1 to 3, wherein the upper wall of the housing cover has a thickness, measured in a direction perpendicular to its surface, which is at least 20% less than a first thickness of the side wall, and / or the upper wall of the housing cover has a thickness, measured in a direction perpendicular to its surface, which is at least 20% less than a second thickness of the side wall.

38. The multi-laser device according to any of the preceding claims 1 to 3, wherein the upper wall of the housing cover has a thickness, measured in a direction perpendicular to its surface, which is at least 30% less than a first thickness of the side wall, and / or the upper wall of the housing cover has a thickness, measured in a direction perpendicular to its surface, which is at least 30% less than a second thickness of the side wall.

39. The multi-laser device according to any of the preceding claims 1 to 3, wherein, the substrate comprises or consists of ceramic, or comprises or consists of metal, and / or the transparent element comprises or consists of glass or sapphire, and / or has an optical protective layer.

40. The multi-laser apparatus of any one of preceding claims 1 to 3, wherein, the transparent element has an anti-reflective coating.

41. A housing cover for a multi-laser device according to any of the preceding claims 1 to 40, the housing cover comprises an upper wall, a side wall which is integrally constructed with the upper wall and ends at a lower edge, and an opening for the passage of electromagnetic radiation, wherein, the side wall has a first thickness, measured in a direction perpendicular to its surface, and a second thickness, measured at the lower edge, which is less than the first thickness, wherein the second thickness, measured at the lower edge (201), corresponds to the thickness of the side wall (200) at its lowest position, the housing cover (3) having a drawn metal housing, the side wall (200) being curved according to a radius R on the inside at the lower edge (201).

42. The housing cover according to claim 41, wherein, the side wall has a surface which is curved outwards at the lower edge on the inside of the housing cover, so that the thickness of the side wall gradually decreases towards its lowest position, and / or wherein the side wall is configured without a protrusion at the outer lower edge.

43. The case cover of claim 41, wherein, the side wall has a protrusion which is less than the first thickness.

44. The case cover of claim 43, wherein, the protrusion is less than half of the first thickness.

45. The case cover of claim 43, wherein, the protrusion is less than a quarter of the first thickness.

46. The housing cover according to any of the preceding claims 41 to 45, wherein the side wall is tapered at the lower edge, and / or wherein the second thickness of the side wall, measured at the lower edge, is at least 5% less than the first thickness of the side wall.

47. The case cover according to any of the preceding claims 41 to 45, wherein, the side wall is tapered along a direction extending from the upper edge to the lower edge.

48. The case cover according to any of the preceding claims 41 to 45, wherein, The second thickness of the sidewall measured at the lower edge is at least 10% less than the first thickness of the sidewall.

49. The case cover according to any of the preceding claims 41 to 45, wherein, The second thickness of the sidewall measured at the lower edge is at least 15% less than the first thickness of the sidewall.

50. The case cover according to any of the preceding claims 41 to 45, wherein, The second thickness of the sidewall measured at the lower edge is at least 20% less than the first thickness of the sidewall.

51. The case cover according to any of the preceding claims 41 to 45, wherein, The second thickness of the sidewall measured at the lower edge is at least 25% less than the first thickness of the sidewall.

52. The case cover according to any of the preceding claims 41 to 45, wherein, The second thickness of the sidewall measured at the lower edge is at least 30% less than the first thickness of the sidewall.

53. The housing cover according to any of the preceding claims 41 to 45, wherein The first thickness of the sidewall measured in a direction perpendicular to the surface of the sidewall corresponds to the thickness of the sidewall at a location adjacent to the upper wall, to the thickness of the sidewall at a location between the upper wall and the lower edge, and / or to an average thickness of the sidewall.

54. The case cover according to any of the preceding claims 41 to 45, wherein, The first thickness of the sidewall measured in a direction perpendicular to the surface of the sidewall corresponds to the thickness of the sidewall at a location adjacent to the upper wall, to the thickness of the sidewall at a location in a range of 25% to 75% between the upper wall and the lower edge.

55. The housing cover according to any of the preceding claims 41 to 45, wherein The second thickness of the sidewall measured at the lower edge is measured in the same direction as the first thickness of the sidewall is measured, or in a direction deviating less than 45 degrees, less than 25 degrees or less than 10 degrees from the direction in which the first thickness of the sidewall is measured, and / or wherein the second thickness of the sidewall measured at the lower edge is measured in a direction extending parallel to the surface of the upper wall, or in a direction deviating less than 45 degrees, less than 25 degrees or less than 10 degrees from the direction.

56. The housing cover according to any of the preceding claims 41 to 45, wherein The housing cover is configured in a shape of a hat such that the sidewall integral with the upper wall is configured as a lateral circumferential wall, and / or wherein at least one opening of the housing cover is arranged in the sidewall and any sidewall, and / or wherein a plurality of openings is provided in the sidewall and any sidewall.

57. The housing cover according to any of the preceding claims 41 to 45, wherein, The housing cover is configured in a shape of a hat such that the sidewall integral with the upper wall is configured as a lateral circumferential wall having four planar sidewalls, and / or wherein three openings are provided in the sidewall and any sidewall.

58. The housing cover according to claim 56, wherein, each of the at least one opening has a greater extent along a direction from the upper wall to the lower edge than along a direction extending in the sidewall perpendicular to the direction, and / or wherein each of the at least one opening has an elliptical shape with a major axis along a direction from the upper wall to the lower edge.

59. The housing cover according to claim 56, wherein, each of the plurality of openings has a greater extent along a direction from the upper wall to the lower edge than along a direction extending in the side wall perpendicular to the direction, and / or wherein each of the plurality of openings has an elliptical shape with a long axis along a direction from the upper wall to the lower edge.

60. The housing cover according to any of the preceding claims 41 to 45, wherein the housing cover comprises a transparent element assigned to the at least one opening.

61. The case cover of claim 60, wherein, the transparent element is provided with a connecting material on the side wall comprising the at least one opening so as to hermetically close the at least one opening.

62. The case cover of claim 60, wherein, the transparent element hermetically closes each of the plurality of openings as an integral part.

63. The housing cover according to claim 60, wherein the transparent element is fixed with a connecting material on the outside of the housing cover.

64. The case cover of claim 60, wherein, the transparent element is fixed on the outside of the side wall or any side wall.

65. The case cover of claim 60, wherein, the transparent element is fixed on the outside of the side wall comprising the at least one opening.

66. The case cover of claim 60, wherein, the transparent element is fixed inclined with respect to the surface of the side wall so that the transparent element has a greater distance from the side wall to the lower edge of the side wall.

67. The case cover of claim 60, wherein, the transparent element is fixed at the lower edge on a protrusion configured on the outside of the side wall and thus inclined with respect to the surface of the side wall.

68. The housing cover according to any of the preceding claims 41 to 45, wherein the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is less than a first thickness of the side wall, and / or wherein the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is less than a second thickness of the side wall.

69. The housing cover according to any of the preceding claims 41 to 45, wherein, the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is at least 10% less than a first thickness of the side wall, and / or wherein the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is at least 10% less than a second thickness of the side wall.

70. The housing cover according to any of the preceding claims 41 to 45, wherein the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is at least 20% less than a first thickness of the side wall, and / or wherein the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is at least 20% less than a second thickness of the side wall.

71. The housing cover according to any of the preceding claims 41 to 45, wherein the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is at least 30% less than a first thickness of the side wall, and / or wherein the upper wall of the housing cover has a thickness measured in a direction perpendicular to its surface which is at least 30% less than a second thickness of the side wall.

72. The housing cover according to claim 60, wherein the transparent element comprises or consists of glass or sapphire, and / or has an optical protective layer.

73. The case cover of claim 60, wherein, the transparent element has an anti-reflective coating.

74. A housing cover according to any of the preceding claims 41 to 73, wherein, The upper wall and the side wall integrally constructed with the upper wall are manufactured or manufacturable by a deep drawing process.

75. A method for producing a housing cover according to any of the preceding claims 41 to 73, comprising: providing a flat starting material, the flat starting material comprising or consisting of metal, introducing one or more openings into the flat starting material, deep drawing the flat starting material in such a way that a housing cover having an upper wall and a side wall integrally constructed with the upper wall is obtained, such that the one or more openings are arranged as elliptical openings in the side wall and / or such that the thickness of the upper wall is smaller than the thickness of the side wall, trimming the side wall at a lower edge in such a way that the side wall has a first thickness measured in a direction perpendicular to its surface and a second thickness measured at the lower edge, the second thickness being smaller than the first thickness, fixing a transparent element on the side wall containing the at least one opening with a connecting material so as to hermetically close the opening, such that the transparent element is inclined with respect to the surface of the side wall.

76. The method of claim 75, wherein, The flat starting material comprises or consists of metal.

77. The method of claim 75, wherein, The openings are circular openings.

78. The method of claim 75, wherein, The first thickness is measured in a direction perpendicular to the surface of the side wall, the second thickness is measured in the same direction at the lower edge.

79. A head-mounted display comprising a multi-laser device according to any of the preceding claims 1 to 40 and / or a housing cover according to any of the preceding claims 41 to 73.

80. The head-mounted display of claim 79, wherein, The head-mounted display is eyewear.

81. The head-mounted display of claim 79, wherein, The head-mounted display is AR eyewear.

82. A head-up display comprising a multi-laser device according to any of the preceding claims 1 to 40 and / or a housing cover according to any of the preceding claims 41 to 73.

83. A motorcycle helmet comprising a head-up display according to claim 82.

84. A projector comprising a multi-laser device according to any of the preceding claims 1 to 40 and / or a housing cover according to any of the preceding claims 41 to 73.

85. A projector of a mobile device comprising a multi-laser device according to any of the preceding claims 1 to 40 and / or a housing cover according to any of the preceding claims 41 to 73.

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