Laser diode and method for manufacturing a laser diode

Abstract

A laser diode and a method for manufacturing a laser diode are disclosed. In an embodiment a laser diode includes a surface emitting semiconductor laser configured to emit electromagnetic radiation and an optical element arranged downstream of the semiconductor laser in a radiation direction, wherein the optical element includes a diffractive structure or a meta-optical structure or a lens structure, and wherein the optical element and the semiconductor laser are cohesively connected to each other.

Claims

1. A laser diode comprising: a surface emitting semiconductor laser configured to emit electromagnetic radiation; and an optical element arranged downstream of the semiconductor laser in a radiation direction, wherein the optical element comprises a diffractive structure or a meta-optical structure or a lens structure, wherein the optical element and the semiconductor laser are cohesively connected to each other by a connector, and wherein the connector surrounds the semiconductor laser and the optical element in lateral directions.

2. The laser diode according to claim 1, wherein the optical element is in direct contact with a radiation exit surface of the surface emitting semiconductor laser facing the optical element.

3. The laser diode according to claim 1, wherein the optical element is formed with a material having the same refractive index as the connector.

4. The laser diode according to claim 1, wherein a region between the optical element and the semiconductor laser is filled with non-gaseous material.

5. The laser diode according to claim 1, wherein the optical element does not completely cover a radiation exit surface of the semiconductor laser facing the optical element.

6. The laser diode according to claim 1, wherein the optical element terminates flush with the semiconductor laser in the lateral directions.

7. The laser diode according to claim 1, wherein the diffractive structure or the meta-optical structure or the lens structure is arranged at a distance from a radiation exit surface of the semiconductor laser facing the optical element.

8. The laser diode according to claim 1, further comprising an anti-reflection layer arranged exclusively on an outwardly exposed surface of the optical element.

9. The laser diode according to claim 1, further comprising an electrical contact surface arranged on a surface of the semiconductor laser facing the optical element, wherein the contact surface is not covered by the optical element.

10. The laser diode according to claim 1, wherein the semiconductor laser comprises electrical contact surfaces exclusively on a side facing away from the optical element.

11. The laser diode according to claim 1, further comprising: a mask, wherein the mask is formed in a vertical direction between the optical element and the semiconductor laser, and wherein the mask is configured to generate a pictogram.

12. The laser diode according to claim 11, further comprising: a spacer, wherein the spacer is arranged in the vertical direction between the optical element and the semiconductor laser, wherein the spacer is transparent for the radiation emitted by the semiconductor laser, wherein the spacer is set at a predetermined distance between the mask and the semiconductor laser, and wherein the semiconductor laser, the spacer and the optical element are cohesively connected to each other.

13. The laser diode according to claim 1, wherein the semiconductor laser and the optical element are laterally enclosed by a cladding, wherein the semiconductor laser and the optical element remain uncovered from the cladding in plan view, and wherein the cladding is configured to reflect or absorb the electromagnetic radiation.

14. The laser diode according to claim 13, wherein the cladding comprises a material which is radiation-absorbing at least for visible light or for light in an infrared spectral range, wherein the cladding completely laterally encloses the semiconductor laser and the optical element, and wherein the cladding partially covers side surfaces of the optical element such that the side surfaces of the optical element remain uncovered by the cladding at least from a vertical height or at least from an upper edge of the diffractive structure, the meta-optical structure or the lens structure.

15. The laser diode according to claim 13, wherein the cladding completely covers side surfaces of the semiconductor laser, wherein the cladding at least partially covers side surfaces of the optical element, wherein the semiconductor laser and the optical element are covered in plan view by a cover layer transmissive for radiation, and wherein the cover layer adjoins the cladding.

16. The laser diode according to claim 15, wherein a material of the cladding is not transmissive for radiation and the cladding is not transmissive for light in an infrared spectral range, and wherein a material and a layer thickness of the cover layer are selected such that the cover layer is not transmissive for light in a visible spectral range and transmissive for light in the infrared spectral range.

17. A method of manufacturing a laser diode, the method comprising: providing a plurality of surface emitting semiconductor lasers in a first composite; providing a plurality of optical elements in a second composite; cohesively connecting the plurality of optical elements in the second composite and the plurality of semiconductor lasers in the first composite, wherein the optical element and the semiconductor laser are at least partially encapsulated or injected in a cladding body formed by a connector; and singulating the optical elements and the semiconductor laser, wherein after singulating exactly one optical element is assigned to each semiconductor laser.

18. A laser diode comprising: a surface emitting semiconductor laser configured to emit electromagnetic radiation; an optical element arranged downstream of the semiconductor laser in a radiation direction; and a mask, wherein the optical element comprises a diffractive structure or a meta-optical structure or a lens structure, wherein the optical element and the semiconductor laser are cohesively connected to each other, wherein the mask is arranged in a vertical direction between the optical element and the semiconductor laser, and wherein the mask is configured to generate a pictogram.

19. The laser diode according to claim 18, further comprising: a spacer, wherein the spacer is arranged in the vertical direction between the optical element and the semiconductor laser, wherein the spacer is transparent for the radiation emitted by the semiconductor laser, wherein the spacer is set at a predetermined distance between the mask and the semiconductor laser, and wherein the semiconductor laser, the spacer and the optical element are cohesively connected to each other.

20. The laser diode according to claim 18, wherein the semiconductor laser, the mask and the optical element are laterally enclosed by a cladding, wherein the semiconductor laser and the optical element remain uncovered from the cladding in plan view, and wherein the cladding is configured to reflect or absorb the electromagnetic radiation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Advantageous embodiments and developments of the laser diode and the method of manufacturing a laser diode will become apparent from the exemplary embodiments described below in association with the figures:

(2) FIGS. 1, 2, 3 and 5D show different exemplary embodiments of a laser diode;

(3) FIGS. 4, 5A, 5B, 5C and 5D show different methods steps of the method of manufacturing a laser diode;

(4) FIGS. 6, 7, 8 and 9 show further exemplary embodiments of a laser diode or a method of manufacturing a laser diode; and

(5) FIGS. 10A, 10B, 10C, 11A and 11B show further exemplary embodiments of a laser diode or a method of manufacturing a laser diode.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(6) In the exemplary embodiments and figures, similar and similarly acting constituent parts are provided with the same reference symbols. The elements illustrated in the figures and their size relationship among one another should not be regarded as true to scale. Rather, individual elements may be represented with an exaggerated size for the sake of better representability and/or for the sake of better understanding.

(7) FIG. 1 shows a schematic sectional view of a laser diode 1 described here according to a first exemplary embodiment. The laser diode comprises a surface-emitting semiconductor laser 10, which is configured to emit electromagnetic radiation E. In particular, the semiconductor laser 10 is configured to emit electromagnetic radiation E perpendicular to its main extension plane. In particular, the semiconductor laser 10 is a VCSEL. For example, the semiconductor laser 10 is formed with a layer stack comprising several semiconductor layers. During normal operation, the semiconductor laser emits electromagnetic radiation E from the semiconductor layers in a radiation direction L that is parallel to the stacking direction, for example.

(8) Further, the laser diode 1 comprises a carrier 30 arranged on a major surface of the semiconductor laser 10. For example, the carrier 30 is a substrate on which the semiconductor laser 10 is manufactured. In particular, the semiconductor laser 10 is manufactured by means of an epitaxial process on the carrier 30. An optical element 20 is arranged on one side of the semiconductor laser 10 facing away from the carrier 30. The optical element 20 is arranged downstream of the semiconductor laser 10 in the radiation direction L. The optical element 20 comprises a diffractive structure 200 or a meta-optical structure 200 or a lens structure 200 which is configured to influence electromagnetic radiation E emitted by the semiconductor laser 10. For example, the diffractive structure 200 comprises elements 205 arranged periodically along the main plane of extension of the optical element 20, which in at least one spatial direction transverse to the emission direction L have a magnitude in the order of the wavelength range of the emitted electromagnetic radiation E. For example, the optical elements 205 are formed as recesses in a first layer 201 of the optical element 20. In particular, the recesses with which the elements 205 are formed may be filled with a gaseous material. The elements 205, which are shown schematically in FIG. 2, form substructures of the diffractive structure 200 or the meta-optical structure 200 or the lens structure 200.

(9) The semiconductor laser 10 and the optical element 20 are mechanically fixed to each other by means of a connection means 50. For example, the connection means 50 is an adhesive, in particular an epoxy resin or a silicone. The connection means 50 is arranged on a radiation exit surface 10a of the laser diode 10. The connection means 50 forms in particular a connecting layer 50. The connecting layer 50 is arranged in a vertical direction, for example, between the optical element 20 and the semiconductor laser 10. For example, a region between the optical element 20 and the semiconductor laser 10 is filled with non-gaseous material. In particular, the connection means 50 completely covers the radiation exit surface 10a. The optical element 20, in particular the first layer 201, is formed, for example, with a material having the same refractive index as the connection means 50.

(10) A first contact surface 41 and a second contact surface 42 are arranged on the carrier 30. By means of the first contact surface 41 and the second contact surface 42, the laser diode 1 can be electrically contacted and operated. The first contact surface 41 is located on a side of the carrier 30 facing away from the semiconductor laser 10. For example, the side of the carrier 30 facing away from the semiconductor laser 10 is completely covered by the first contact surface 41. The laser diode 1 can be mounted with the first contact surface 41 on an electrically conductive surface, which can also serve as a heat sink for the laser diode 1. The second contact surface 42 is arranged on one side of the carrier 30, facing away from the first contact surface 41, laterally next to the semiconductor laser 10. For example, the second contact surface 42 can be electrically contacted by means of a bonding wire 43.

(11) FIG. 2 shows a schematic sectional view of a laser diode 1 described here according to another exemplary embodiment. In contrast to the exemplary embodiment shown in FIG. 1, the semiconductor laser 10 is not arranged on a carrier 30. In particular, the semiconductor laser 10 comprises electrical contact surfaces 4 exclusively on a side facing away from the optical element 20. The semiconductor laser 10 and the optical element 20 are cohesively connected to each other by a connection means 50. For example, the optical element 20 is formed with a material which has the same refractive index as the connection means 50. In particular, the electromagnetic radiation E emitted by the semiconductor laser 10 is not refracted at the interface between the connection means 50 and the optical element 20.

(12) The optical element 20 terminates flush with the semiconductor laser 10 in lateral directions R which are perpendicular to the radiation direction L of the semiconductor laser 10. In particular, the optical element 20 does not project beyond the semiconductor laser 10 in lateral directions R. The optical element 20 is formed by a first layer 201 and a second layer 202. The second layer 202 is not contiguous and is arranged in recesses of the first layer 201. For example, the second layer 202 is completely surrounded on all sides by the first layer 201. The first 201 and the second 202 layer form elements 205 which act as a diffractive structure 200 for the electromagnetic radiation E emitted by the semiconductor laser 10.

(13) It is possible that the elements 205 are formed by substructures of the meta-optical structure 200 or the lens structure 200. The substructures of the meta-optic structure 200 or the lens structure 200 can be completely surrounded on all sides by the first layer 201. Especially in this sense the diffractive structure 200 or the meta-optic structure 200 or the lens structure 200 is embedded in the optical element 20, especially in the first layer 201. The first layer 201 serves in particular as a planarization layer and/or as an encapsulation layer of the optical element 20. Deviating from FIG. 2, it is possible that several or all elements 205, which are formed in particular by substructures of the meta-optical structure 200 or the lens structure 200, are formed contiguously. For example, the elements 205 form a lens row, a lens matrix from several lens rows of the lens structure 200 or a meta lens, in particular from nanosubstructures of the meta-optic structure 200.

(14) The diffractive structure 200, the meta-optical structure 200 or the lens structure 200 is arranged at a distance from the side 10a of the semiconductor laser 10 facing the optical element. In particular, the distance D between the diffractive structure 200, the meta-optical structure 200 or the lens structure 200 and the radiation exit surface 10a can be adapted via the thickness of the connection means 50 and/or the thickness of the optical element 20, in particular the first layer 201.

(15) If the optical element 20 comprises a lens structure 200, the element 205 can be formed as a lens. In particular, element 205 forms an optical substructure of the lens structure 200. The majority of elements 205 may form one or more rows of lenses. The elements 205 can be embedded in the first layer 201. The elements 205 may have a higher or lower refractive index than a material of the first layer 201. For example the refractive indices of the elements 205 and the material of the first layer 201 differ by at least 0.1, 0.2, 0.5 or by at least 0.5, for example between 0.1 and 1 inclusive or between 0.1 and 2 inclusive. The first layer 201 may be formed as a planarization layer or as an encapsulation layer of the diffractive structure 200, the meta-optical structure 200, the lens structure 200 or the optical element 20.

(16) Furthermore, an anti-reflection layer 8 is arranged on a surface of the optical element 20 facing away from the semiconductor laser 10. In particular, the anti-reflection layer 8 is arranged exclusively on an outwardly exposed surface 1a of the optical element 20.

(17) FIG. 3 shows a schematic sectional view of a laser diode 1 described here according to another exemplary embodiment. In this exemplary embodiment, the optical element 20 and the semiconductor laser 10 are cohesively connected to each other by means of the connection means 50. Furthermore, the connection means 50 surrounds the semiconductor laser 10 and the optical element 20 in lateral directions R. In particular, all surfaces of the optical element 20 and the semiconductor laser 10 which run transversely to the radiation direction L of the semiconductor laser 10 are completely covered by the connection means 50. In particular, the connection means 50 also completely covers the surface of the optical element 20 facing away from the semiconductor laser 10. For example, the connection means 50 is a capsulation means which is transparent to the electromagnetic radiation E emitted by the semiconductor laser 10.

(18) The semiconductor laser 10 is cohesively connected to a housing 60 on a side facing away from the optical element 20 by means of the second contact surface 42. For example, the housing 60 is at least partially electrically conductive and serves as a heat sink and for electrical contacting of the semiconductor laser 10. The first contact surface 41 is arranged on the radiation exit surface 10a of the semiconductor laser 10. The first contact surface 41 is electrically conductively connected to the housing 60 by means of a bonding wire 43. In particular, the bonding wire 43 and the second contact surface 42 are not electrically conductively connected to each other via the housing 60. The first electrical contact surface 41 is arranged on the radiation exit surface boa of the semiconductor laser 10 facing the optical element 20. The optical element 20 does not completely cover the radiation exit surface boa of the semiconductor laser 10. In particular, the first contact surface 41 is not covered by the optical element 20.

(19) The optical element 20 is formed by a first layer 201 and a second layer 202. The first layer 201 has a plurality of recesses which are completely filled with the material of the second layer 202. The first 201 and the second 202 differ in at least one optical property, such as their refractive index, their reflectivity and/or their absorption for electromagnetic radiation E emitted by the semiconductor laser 10. The first 201 and the second 202 form a diffractive structure 200 comprising a plurality of elements 205 configured to influence electromagnetic radiation E emitted by the semiconductor laser 10.

(20) According to FIG. 3, the semiconductor laser 10 projects beyond the optical element 20 in a lateral direction. The semiconductor laser 10 can be partially free of a covering by the optical element 20 so that it can be electrically contacted, in particular on its side facing the optical element 20. In plan view, the optical element 20 covers the semiconductor laser 10 only partially. For example, the semiconductor laser 10 has a surface facing the optical element 20 with a free region which is free of a covering by the optical element 20. One or more contact surfaces 41 and/or 42 may be formed on the free region.

(21) Deviating from FIG. 3, it is possible that the optical element 20 shown in FIG. 3 is constructed analogously to the optical element 20 shown in FIG. 2. Deviating from FIG. 3, it is also possible that both the first contact surface 41 and the second contact surface 42 are arranged analogously to the exemplary embodiment of a laser diode 1 shown in FIG. 2 on a rear side of the semiconductor laser 10 facing away from the optical element 20. The semiconductor laser 10 is configured in particular as a surface-mountable component and can only be electrically contacted externally via its rear side. The first contact surface 41 and the second contact surface 42 are particularly assigned to different electrical polarities of the semiconductor laser 10 and the laser diode 1, respectively. For example, the semiconductor laser 10 has the form of a flip chip.

(22) FIG. 4 shows part of a method of manufacturing a plurality of laser diodes 1. In this method step, the semiconductor lasers 10 are cohesively connected to a housing 60 with their second contact surface 42. The semiconductor lasers 10 are electrically conductively connected to the housing 60 by means of a bonding wire 43 at their first contact surface 41. The connection means 50, which serves as a capsulation means, is arranged in the housing 60.

(23) The connection means 50 is arranged at least on the radiation exit surface 10a of the semiconductor laser 10. In addition, the connection means 50 is arranged in the housing 60 such that side surfaces of the semiconductor laser 10, which connect the side of the semiconductor laser 10 facing away from the optical element 20 and the side of the semiconductor laser 10 facing away from the optical element 10a, are covered. The connection means 50, for example, can be arranged in a method step in the housing 60 such that all radiation exit surface 10a of the semiconductor laser 10 are covered with a predetermined thickness of the connection means 50. In a further method step, optical elements 20 can be arranged on the semiconductor lasers 10, so that the optical elements 20 are arranged downstream of the semiconductor lasers 10 in a radiation direction L. In a subsequent method step, additional connection means 50 is arranged in the housing 60 so that the optical elements 20 are completely covered by the connection means 50. In a subsequent method step, the laser diodes 1 are singulated along the separation lines 7. For example, the laser diodes 1 are singulated along the separation lines 7 by means of a sawing or laser cutting process.

(24) FIG. 5A shows a method described here for the manufacturing of a laser diode 1 after method steps A and B. In method step A, a plurality of surface emitting semiconductor lasers 10 were provided in a first composite 110. For example, the semiconductor lasers 10 are arranged on a common carrier 30. In particular, the semiconductor lasers 10 on the common carrier 30 are manufactured in a common manufacturing process. Contact surfaces 4 are arranged on a side of the carrier 30 facing away from the semiconductor lasers 10.

(25) Furthermore, in a method step B, a plurality of optical elements 20 with diffractive structures 200, meta-optical structures 200 or with lens structures 200 are provided in a second composite 120. The plurality of optical elements 20 is cohesively connected to each other. In particular, the optical elements 20 are manufactured in a common process. The diffractive structures 200, the meta-optical structures 200 or the lens structures 200 are formed with elements 205 which are arranged, for example, on a surface of a first layer 201 of the optical element 20 facing away from the laser diode 10. Alternatively, the diffractive structures 200, the meta-optical structures 200 or the lens structures 200 can be completely surrounded by the material of the first layer 201 of the optical element 20. For example, the diffractive structures 200 or the lens structures 200 can be formed by varying the thickness of the optical element 20.

(26) FIG. 5B shows a schematic sectional view of a method described here for the manufacturing of a laser diode after method step C. In method step C, the plurality of optical elements in a composite and the plurality of semiconductor lasers in a composite were cohesively connected to each other. For example, the first composite 110 and the second composite 120 were cohesively connected to each other via bonding. Alternatively, the first bond 110 and the second bond 120 can be cohesively connected to each other by means of a connection means 50.

(27) FIG. 5C shows a method step D of a method described here for manufacturing a laser diode 1. In a method step D, the first composite 110 and the second composite 120 are singulated. The optical elements 20 and the semiconductor lasers 10 are cut perpendicular to their main extension plane along the separation line 7. For example, the first composite 110 and the second composite 120 are cut using a laser cutting process, a sawing process or an etching process. After singulation, each semiconductor laser 10 is assigned exactly one optical element 20.

(28) FIG. 5D shows the laser diodes 1 after carrying out method steps A to D according to the method described here for manufacturing a laser diode 1. In particular, the laser diode 1 described here has electrical contact surfaces 4 exclusively on one side facing away from the optical element 20. The semiconductor lasers 10, the contact surfaces 4, the carriers 30 and the optical elements 20 are cut in a common method step. The optical elements 20, the semiconductor lasers 10 and the carriers 30 terminate flush with each other in lateral directions.

(29) The exemplary embodiment shown in FIG. 6 of a laser diode 1 corresponds essentially to the exemplary embodiment shown in FIG. 3. In contrast to this, the connection means 50 is arranged exclusively between the semiconductor laser 10 and the optical element 20. The semiconductor laser 10 and the optical element 20 are completely enclosed in the lateral direction by a cladding 90. For example, the side surfaces of the semiconductor laser 10 and/or the connection means 50 are completely covered by a material of the cladding 90. According to FIG. 6, the side surfaces of the optical element 10 are only partially covered by the cladding material 90, in particular substantially up to the vertical height of the elements 205. However, it is possible that the side faces of the optical element 10 are completely covered by the cladding material 90. In plan view of the optical element, the semiconductor laser 10 or the optical element 10 is preferably free of a covering by the cladding 90.

(30) For the electromagnetic radiation emitted by the semiconductor laser 10, the material of the cladding 90 may be chosen to be not transmissive. For example, the cladding material 90 acts radiation-absorbing or radiation-reflecting. In particular, the cladding is not transmissive for electromagnetic waves with a peak wavelength of the light emitted by the semiconductor laser 10. By covering the side surfaces of the semiconductor chip 10 and/or the optical element 20, it can be prevented that the electromagnetic radiation emitted by the semiconductor laser 10 is emitted laterally from the semiconductor laser 10 or from the optical element 20, before it hits the diffractive structures 200, the meta-optical structures 200 or the lens structures 200.

(31) A layer, such as the cladding 90 or the cover layer 91, is transmissive for radiation if preferably at least 50%, 60%, 70%, 80% or at least 90% of the radiation emitted by the semiconductor laser can be transmitted through this layer. On the other hand, a layer is not transmissive if it transmits not more than 50%, 40%, 30%, 20%, 10% or not more than 5% of the radiation emitted by the semiconductor laser.

(32) According to FIG. 6, the laser diode 1 comprises a cover layer 91. In particular, the cover layer 91 directly adjoins the cladding 90 and/or a surface of the optical element 20 facing away from the semiconductor laser 10 or the anti-reflection layer 8. In plan view, the cover layer 91 can cover the optical element 20, the semiconductor laser 10 and/or the cladding 90, in particular completely. For the electromagnetic radiation emitted by the semiconductor laser 10, the material of the cladding 91 may be transmissive. It is possible that the cover layer 91 is not transmissive to visible light and transmissive to electromagnetic radiation in the infrared range, or vice versa.

(33) In FIG. 6, the housing 60 comprises a cavity in which the cover layer 91, the cladding 90, the optical element 20 and/or the semiconductor laser 10 is/are arranged. Deviating from FIG. 6, it is possible that the housing 60 comprises only a laterally extending region and no vertically extending regions. In this case, the housing 60 does not have a cavity with inner walls from the vertically extending regions, but only a laterally extending region on which the semiconductor laser 10 is arranged. In particular, the laterally extending region is in the form of a carrier, in particular in the form of a printed circuit board, to which the semiconductor laser is electrically conductively connected. Such a laser diode 1 is shown, for example, in FIG. 7. Such a laser diode 1 comprises outer side surfaces which are formed by surfaces of the cladding 90 and/or the cover layer 91. In particular, laser diode 1 is formed as a chip-scale package (CSP) whose lateral and/or vertical expansion is approximately in the same order of magnitude as the lateral and/or vertical expansion of the semiconductor laser 10.

(34) The exemplary embodiment shown in FIG. 7 for a part of a method of manufacturing a plurality of laser diodes 1 essentially corresponds to the exemplary embodiment shown in FIG. 4. In contrast to this, the cladding body or the cladding 90 is made of a material different from a material of the connection means 5, analogous to the exemplary embodiment shown in FIG. 6. For example, the cladding is molded or formed by filling a cavity in which the semiconductor laser 10 or a plurality of semiconductor lasers 10 are arranged. The arrangement of the claddings 90 and/or the cover layer 91 in FIGS. 6 and 7 may be identical. In contrast to FIGS. 6 and 7, the optical element 10 may take other forms described here.

(35) The exemplary embodiment shown in FIG. 8 for a laser diode 1 is essentially the same as the exemplary embodiment shown in FIG. 6 for a laser diode 1. In contrast to this, the semiconductor laser 10 comprises a first contact surface 41 and a second contact surface 42 on a rear side of the semiconductor laser 10 facing away from the optical element 20. The semiconductor laser 10 can therefore only be electrically contacted externally via its rear side.

(36) The exemplary embodiment shown in FIG. 9 for a method step of manufacturing a plurality of laser diodes 1 essentially corresponds to the exemplary embodiment shown in FIG. 7. In contrast to this, the semiconductor laser 10 or the semiconductor lasers 10 can be electrically contacted externally, analogous to FIG. 8, exclusively via its rear side(s).

(37) The exemplary embodiment shown in FIG. 10A for a laser diode 1 corresponds essentially to the exemplary embodiment shown in FIG. 6 for a laser diode 1. In contrast to this, the laser diode 1 comprises a mask 25. The mask 25 is arranged in vertical direction between the optical element 20 and the semiconductor laser 10. In FIG. 10A, the mask 25 is arranged between the optical element 20 and the connection means 50. In particular, mask 25 is located on the back of optical element 20, i.e., on a surface of optical element 20 facing the semiconductor laser 10. It is possible that mask 25 is applied directly to the optical element 20. The mask 25 can be applied to the optical element by means of a coating or a deposition method, for example by vapor deposition or sputtering.

(38) In particular, the mask 25 is a shadow mask. The mask 25 may comprise patterns which, in particular, form a predefined pictogram. The mask 25 is preferably a mask 25 that forms a pictogram. The mask 25 may comprise regions transmissive for radiation that define the shape of the pictogram to be displayed. Regions that are not transmissive for radiation may be formed by a radiation-absorbing and/or a radiation-reflecting material. For example, the regions not transmissive for radiation of the mask 25 may be formed by a metal or metal alloy.

(39) The mask 25 may comprise regions transmissive for radiation that allow the radiation emitted by the semiconductor laser 10 to pass the mask 25 unhindered or essentially unhindered. The regions transmissive for radiation may be openings or free regions of the mask 25. It is also possible that the regions transmissive for radiation of the mask 25 are formed by a material transmissive for radiation. Due to the regions transmissive for radiation and the regions not transmissive for radiation, the mask can form an arbitrary pattern and thus an arbitrary pictogram. During operation, the particularly compact laser diode 1 with the semiconductor laser 10, the mask 25 and the optical element 20 can project a pictogram onto a target surface without any additional aids.

(40) The exemplary embodiment shown in FIG. 10B for a laser diode 1 corresponds essentially to the exemplary embodiment shown in FIG. 8 for a laser diode 1. In contrast to this, the laser diode 1 comprises a mask 25 analogous to the exemplary embodiment shown in FIG. 10A. In contrast to the exemplary embodiment shown in FIG. 10A, the laser diode 1 comprises a spacer 51 as shown in FIG. 10B. The spacer 51 is arranged along a vertical direction between the semiconductor laser 10 and the mask 25. The spacer 51 is preferably transmissive for radiation. For example, the spacer 51 is formed of glass, quartz glass or a glass-like material. The spacer 25 can be used to adjust an ideal distance between the semiconductor laser 10 and the mask 25, so that the mask 25 is optimally, approximately homogeneously, illuminated. According to FIG. 10B, the spacer 25 is arranged between two connecting layers 50 and, in particular, adjoins directly to these connecting layers 50. The semiconductor laser 10 and the mask 25 can each be directly adjacent to one of the two connection layers 50.

(41) The exemplary embodiment shown in FIG. 10C for a laser diode 1 is essentially the same as the exemplary embodiment shown in FIG. 10B for a laser diode 1. In contrast, the mask 25 is not arranged on the back of the optical element 20 but on a surface of the spacer 51. In this sense the mask 25 is not part of the optical element 20 but part of the spacer 51. While the mask 25 is arranged according to FIG. 10B on the optical element 20 and only mechanically connected to the spacer 51 via the connecting layer 50, the mask 25 according to FIG. 10C is arranged on the spacer 51 and only mechanically connected to the optical element 20 via the connecting layer 50.

(42) The mask 25 is arranged in particular on a surface of the spacer 51 facing away from the semiconductor laser 10. It is possible that the mask 25 is applied directly to the spacer 51. The mask 25 can be applied to the spacer 51 by means of a coating or a deposition process, for example by vapor deposition or sputtering.

(43) The exemplary embodiments shown in FIGS. 11A and 11B for a part of a method of manufacturing a plurality of laser diodes 1 essentially correspond to the exemplary embodiments shown in FIGS. 7 and 9.

(44) In contrast, the laser diodes 1 each comprise a mask 25, a spacer 51 and, in particular, an anti-reflection layer 8. The laser diode 1 described in connection with FIGS. 1 to 9 may also comprise such a mask 25 and/or such a spacer 51, wherein the mask 25 and the spacer 51 are described in more detail in particular in connection with FIGS. 10A to 10C. According to FIGS. 11A and 11B, the cladding 90 completely covers the side surfaces of the semiconductor laser 10, the mask 25 and/or the spacer 51 as well as the connection layer 50 or the connection layers 50. The antireflection layer 8 is free of a covering by the cladding 90. Apart from one side facing the optical element 20, the antireflection layer 8 in particular is completely covered by the cover layer 91.

(45) Deviating from the FIGS. 8, 9, 10B, 10C and 11B, it is possible that the finished laser diode 1 is free of a housing 60, as shown in these figures. For example, the housing 60 can be completely removed from the laser diode 1 or from the laser diodes 1. Such a laser diode 1 has a rear side, which is formed in particular by the rear side of the semiconductor laser 10 and/or by the rear surface of the cladding 90. In particular, the contact surfaces 41 and 42 on the rear side of the laser diode 1 are freely accessible. In particular, such a laser diode 1 is formed as a surface-mountable component. A vertical overall height of the laser diode 1 is given in particular exclusively by the sum of the vertical heights of the cladding 90 and the cover layer 91. A mechanically stable and flat CSP component (Chip-scale package) with a particularly low overall height can thus be achieved.

(46) The patent application claims the priority of German patent application DE 10 2017 112 235.4, the disclosure content of which is hereby incorporated by reference.

(47) The invention is not restricted to the exemplary embodiments by the description on the basis of said exemplary embodiments. Rather, the invention encompasses any new feature and also any combination of features, which in particular comprises any combination of features in the patent claims and any combination of features on the exemplary embodiments, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.