Optoelectronic device and method

Abstract

Optoelectronic device (10) for generating electromagnetic radiation, comprising: a substrate (11), a functional layer structure (16), a first electrode (14) arranged on a side of the functional layer structure (16) facing the substrate (11) and a second electrode (15) arranged on a side of the functional layer structure (16) facing away from the substrate (11), wherein the functional layer structure (16) is configured to generate electromagnetic radiation when the functional layer structure (16) is energized by means of the first electrode (14) and the second electrode (15), an insulating layer (13) which electrically insulates at least one of the electrodes (14, 15) from the substrate (11), wherein the at least one electrode which is electrically insulated from the substrate (11) by the insulating layer (13) has a contact (24, 25) for contacting, a planarization (12) to compensate for a roughness of one of the main surfaces (11a) of the substrate (11) facing the first electrode (14) and the second electrode (15), and an encapsulation layer (17) to protect the functional layer structure (16) from moisture, which has a recess that makes the contact (24, 25) accessible for contacting, wherein the insulating layer (13) is set up and arranged to act as a moisture diffusion barrier for moisture diffusion from the contact (24, 25) to the planarization (12), where the planarization (12) as seen from above on the main surface (11a) of the substrate (11) does not overlap with the contact (24, 25), where, viewed from above on the main surface of the substrate (11), the planarization (12) and the recess do not overlap, wherein the planarization (12) is designed and arranged such that at least one of the first and second electrodes (14) has an interface (14a) which has a lower roughness in at least a first region (34a) than in a second region (34b), and wherein the optoelectronic device is configured to display information visible to an external observer by the interaction of the first area (34a) and the second area (34b).

Description

[0001] The invention relates to an optoelectronic device for generating electromagnetic radiation and a method for providing it.

[0002] The following publications concern optoelectronic devices: CH 709 370 A1, DE 11 2004 000 937 B4, DE 10 2012 200 084 A1, US 2011 / 0 250 392 A1, US 2015 / 0 357 598 A1, EP 1 492 387 A1.

[0003] It is known to arrange an insulating layer between the substrate and an electrode in optoelectronic devices for generating electromagnetic radiation, thus isolating the electrode from the substrate. The insulating layer can also have a planarizing effect. Known insulating layers with a high planarizing effect are made of organic materials. Such materials exhibit a high moisture transport capacity, which can reduce the robustness of the optoelectronic device, a disadvantage particularly in automotive applications.

[0004] The object of the invention is to propose an optoelectronic device for generating electromagnetic radiation with a simple yet robust design.

[0005] This problem is solved by the features of claim 1 and claim 10. Advantageous embodiments are specified in dependent claims.

[0006] An optoelectronic device for generating electromagnetic radiation comprises a preferably planar substrate, a functional layer structure, a first electrode arranged on a side of the functional layer structure facing the substrate, and a second electrode arranged on a side of the functional layer structure facing away from the substrate, wherein the functional layer structure is configured to generate electromagnetic radiation when the functional layer structure is energized by means of the first electrode and the second electrode.

[0007] The optoelectronic device also includes an insulating layer that electrically insulates at least one of the two electrodes, i.e., the first electrode or the second electrode, or both the first electrode and the second electrode, from the substrate.

[0008] Furthermore, the optoelectronic device includes a planarization feature to compensate for the roughness of a main surface of the substrate facing the electrodes.

[0009] The at least one electrode, which is electrically insulated from the substrate by the insulating layer, has a contact for contacting. This contact preferably serves for external contacting, i.e., for contacting from outside the optoelectronic device. The contact can be formed by a contactable area on one of the two electrodes.

[0010] The insulation layer is set up and arranged to act as a moisture diffusion barrier to prevent moisture diffusion from the contact to the planar surface.

[0011] This insulating layer, which prevents moisture from reaching the planar surface from contact, consequently allows the use of a planar surface in which moisture easily spreads, while maintaining a robust construction.

[0012] The previously described combination of planarization and insulation layer therefore allows for a very good planarization effect and at the same time very good protection against the penetration of moisture.

[0013] The planarization is preferably arranged between the substrate and the functional layer structure. This allows for a simple design of the optoelectronic device.

[0014] Planarization can refer in particular to a planarization layer.

[0015] The first electrode can comprise or consist of a first electrode layer. The second electrode can comprise or consist of a second electrode layer.

[0016] The planarization is preferably arranged such that at least one region of the functional layer structure is planarized by the planarization. This means that the functional layer structure in this region exhibits a lower roughness than would be the case without the planarization.

[0017] The first electrode, the second electrode, the functional layer structure, the insulating layer, the planarization, and the contact can be arranged at least partially, e.g., at least in certain areas, on the main surface of the substrate. For example, they can be in direct or indirect contact with this surface, at least in certain areas. In particular, they can be coated onto this surface according to a layer sequence.

[0018] The fact that a layer or element is arranged or applied "on"—meaning "over"—another layer or element can mean, here and in the following, that the layer or element is in direct mechanical and / or electrical contact with the other layer or element. It can also mean that the layer or element is arranged indirectly on or over the other layer or element. In this case, further layers and / or elements may be arranged between the layer and the element.

[0019] The fact that a layer or element is arranged "between" two other layers or elements can mean, here and in the following, that the layer or element is in direct mechanical or electrical contact or in indirect contact with one of the other two layers or elements and in direct mechanical and / or electrical contact or indirect contact with the other of the two layers or elements. In the case of indirect contact, further layers and / or elements may be arranged between the layer and at least one of the other two layers, or between the layer and at least one of the other two elements.

[0020] The planarization is preferably arranged such that at least one area of ​​the contact is not planarized. This means that, according to this preferred embodiment, at least one area of ​​the contact has the same roughness as it would have if the planarization were absent. This facilitates the moisture diffusion barrier effect of the insulating layer. It is particularly preferred that the entire contact is not planarized.

[0021] Preferably, when viewed from above on the main surface of the substrate, the planarization does not extend over a region of the contact, or better yet, over the entire contact. In other words, when viewed from above on the main surface of the substrate, the contact and the planarization do not overlap completely, or better yet, not at all. This preferred embodiment enables a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0022] Preferably, when viewed from above on the main surface of the substrate, the insulating layer extends over a region of the contact and, more preferably, over the entire contact. In other words, preferably, when viewed from above on the main surface of the substrate, the insulating layer and the contact overlap, and more preferably, they overlap completely. This allows for a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0023] Preferably, the insulating layer is designed and arranged to act as a moisture diffusion barrier in the lateral direction. This enables a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0024] According to one embodiment, the insulating layer is designed and arranged so that it does not act as a moisture diffusion barrier in a direction perpendicular to the lateral direction of the insulating layer. This allows for a simple design of the optoelectronic device. For example, the insulating layer can be produced particularly easily and cost-effectively. For instance, the insulating layer can have holes, so-called pinholes, which do not significantly impair the electrical insulation but allow moisture diffusion in a direction perpendicular to the lateral direction of the insulating layer.

[0025] A lateral direction of the insulation layer is understood, for example, as a direction running along the interface of a planar insulation layer, neglecting surface roughness, or, for example, as a tangent to an interface of a curved insulation layer, neglecting surface roughness. Similarly, a top view of the main surface of the substrate is understood, for example, as a perpendicular projection onto the main surface of a planar substrate, or, for example, as a projection onto the main surface of a curved planar substrate, which is locally perpendicular to the main surface at every point, neglecting surface roughness.

[0026] Preferably, an interface of the first electrode facing away from the substrate, or an interface of the second electrode facing the substrate, has a reflectivity of at least 50%, preferably at least 80% or even at least 90%, for electromagnetic radiation incident on this interface in a region that is planarized by planarization. The reflectivities are in each case related to the radiant power. Particularly preferably, the interface in the aforementioned region has the aforementioned reflectivity for one or more wavelengths of the visible light spectrum from 380 nm to 780 nm, or as the arithmetic mean over the wavelength range of visible light, or as the arithmetic mean for the entire visible light spectrum.Particularly preferably, the interface in the previously described region exhibits the previously described reflectivity for one or more wavelengths of the electromagnetic radiation generated by the functional layer structure, or relative to the radiant power of the electromagnetic radiation generated by the functional layer structure. This allows for the realization of a mirror-like electromagnetic device. The reflectivity of the aforementioned interface can, in particular, relate to radiation incident perpendicular to the interface. The reflectivity of the aforementioned electrode interface depends, among other things, on the refractive index of the electrode and on the refractive index of the adjacent layer(s).The fact that the aforementioned area of ​​the interface of the first electrode is planarized by planarization means that it has a lower roughness than would be the case if planarization were not present.

[0027] Preferably, the optoelectronic device is configured to emit at least a portion of the generated electromagnetic radiation through the second electrode. It may also be configured to prevent the generated electromagnetic radiation from passing through the substrate.

[0028] Preferably, the optoelectronic device is configured to emit at least a portion of the generated electromagnetic radiation through the first electrode and the substrate. It may also be configured to prevent the generated electromagnetic radiation from being emitted through the second electrode.

[0029] The optoelectronic device also includes an encapsulation layer to protect the functional layer structure from moisture, which has a recess that makes contact accessible for contacting, e.g. for external contacting.

[0030] The encapsulation layer can be a single layer, a stack of layers, or a layered structure. In particular, the encapsulation layer can be a thin-film encapsulation (also known as TFE).

[0031] Preferably, the encapsulation layer is arranged at least partially on a side of the second electrode that is inclined away from the substrate. This allows for good encapsulation of the encapsulation layer.

[0032] The insulating layer and the encapsulating layer are preferably arranged on opposite sides of the at least one electrode, which is insulated from the substrate by the insulating layer. This ensures good encapsulation by the encapsulating layer.

[0033] Viewed from above, the planarization and the recess do not overlap the main surface of the substrate. In other words, preferably, the planarization does not extend into a region of the recess when viewed from above, and more preferably, the planarization does not extend across the entire recess when viewed from above. This allows for a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0034] Preferably, when viewed from above on the main surface of the substrate, the insulating layer and the recess overlap; more preferably, they overlap completely. In other words, when viewed from above on the main surface of the substrate, the insulating layer preferably extends over part of the recess. More preferably, it extends over the entire recess when viewed from above on the main surface of the substrate. This allows for a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0035] Preferably, the insulating layer has a thickness of at least 1 µm. It can also have a thickness that is at least twice the roughness of the substrate, preferably at least twice the maximum roughness of the substrate. This ensures sufficient stability, e.g., against punctures of the insulating layer.

[0036] Preferably, the insulating layer is positioned downstream of the planarization, starting from the substrate. This prevents the diffusion of planarization components into the functional layer structure; that is, the insulating layer can act as a diffusion barrier between the planarization and the functional layer structure. This can be particularly desirable if the planarization comprises or consists of an organic material and, at the same time, the functional layer structure also comprises or consists of an organic material, i.e., the functional layer structure is an organically functional layer structure.

[0037] Ideally, the insulating layer and the substrate work together to completely enclose the planarization. This allows the insulating layer, in conjunction with the substrate, to encapsulate the planarization from moisture on all sides.

[0038] According to an alternative embodiment, the planarization of the insulating layer is a subsequent step, starting from the substrate. The insulating layer can extend across the entire substrate. These alternative embodiments simplify the fabrication of the optoelectronic device; for example, the insulating layer can be applied using a roll-to-roll process before the planarization and fine structuring are carried out.

[0039] Preferably, the electrode, which is electrically insulated from the substrate by the insulating layer, is in direct contact with the insulating layer. This allows for a particularly stable mechanical connection with the electrode, especially when using an insulating layer made of inorganic material.

[0040] The planarization is planarized, i.e., it exhibits a lower roughness on an interface facing away from the substrate than on an interface facing the substrate, preferably by at least a factor of 2, particularly preferably by at least a factor of 5, and most preferably by at least a factor of 20. Preferably, the planarization on an interface facing away from the substrate has a roughness of less than or equal to 500 nm, particularly preferably less than or equal to 200 nm, and most preferably less than or equal to 50 nm.

[0041] The substrate, on the other hand, can have a roughness greater than or equal to 500 nm on the main surface, or greater than or equal to 1000 nm, or even greater than or equal to 5000 nm.

[0042] The average roughness of a reference area, represented by the symbol R a The mean roughness Rm represents the average distance of all points on the interface within the reference area to a mean plane. The mean plane intersects the actual profile such that the mean distance is minimized. a This corresponds to the arithmetic mean of the absolute deviation from the mean plane.

[0043] Preferably, the planarization process incorporates an organic material. This allows for a particularly effective planarization. For example, the organic material could be selected from the following group of materials: epoxy resin, acrylate, polyurethane, polyimide, silicone, organopolysilazane, polysiloxane, styrene, polyester, polyectone.

[0044] Planarization can be planarization processed from the liquid phase, i.e., a liquid was applied to provide the planarization, which forms the planarization.

[0045] Preferably, the insulating layer comprises an inorganic material. This allows for a particularly good moisture diffusion barrier effect. For example, the insulating layer can comprise an inorganic material selected from the following group of materials: oxide, nitride, oxynitride, carbide, metal oxide, metal nitride, metal oxynitride, metal carbide, ceramic, glass. In particular, the inorganic material can be silicon nitride (SiN) or silicon oxide (SiO₂). x ), silicon oxynitride (SiNO₃) x ), silicon oxycarbonitride (SiCNO₃) x ), aluminum oxide (AlO x ), titanium oxide (TiO₂) x ), antimony-tin oxide (ATO) or silicon carbide (SiC).

[0046] The planarization is designed and arranged in such a way that at least one of the first and second electrodes has an interface that has a lower roughness in at least a first area than in a second area.

[0047] Since the first area has a different roughness than the second area, these areas appear different to an observer, which can make the appearance of the optoelectronic device more interesting and thus improve it.

[0048] The planarization can, for example, be designed and arranged such that an interface of the first electrode facing away from the substrate has a lower roughness in the first region than in the second region. The optoelectronic device is preferably configured to emit at least a portion of the generated electromagnetic radiation through the second electrode. It can also be configured to prevent the generated electromagnetic radiation from being emitted through the substrate.

[0049] Alternatively or additionally, the planarization can also be designed and arranged such that an interface of the second electrode facing the substrate has a lower roughness in the first region than in the second region. The optoelectronic device is preferably configured to emit at least a portion of the generated electromagnetic radiation through the first electrode and the substrate. Furthermore, it can be configured to prevent the generated electromagnetic radiation from being emitted through the second electrode.

[0050] The planarization is preferably arranged between the substrate and the first electrode. This allows for a simple design of the optoelectronic device.

[0051] The first electrode can comprise or consist of a first electrode layer. Accordingly, for example, the first electrode layer on an interface facing away from the substrate can exhibit lower roughness in the first region than in the second region.

[0052] The second electrode can comprise or consist of a second electrode layer. Accordingly, for example, the second electrode layer on an interface facing the substrate can exhibit lower roughness in the first region than in the second region.

[0053] According to a preferred embodiment, the planarization is designed and arranged such that the previously discussed interface is planarized throughout the entire first region and not planarized throughout the entire second region. This means that, according to this preferred embodiment, the first electrode has a lower roughness in the first region than it would have without planarization, and the same roughness in the second region as it would have without planarization.

[0054] The planarization can have at least one recess that creates the second area. This recess can be completely surrounded by the planarization.

[0055] Preferably, when viewed from above, i.e., in a perpendicular projection onto the main surface of the substrate, the planarization extends over the entire first area, while the planarization does not extend over the entire second area. In other words, preferably, when viewed from above, the first area and the planarization completely overlap, while the second area and the planarization do not.

[0056] According to a preferred embodiment, the planarization is designed and arranged such that the previously discussed interface is planarized in the first region and in the second region. In particular, it can be designed and arranged such that the previously discussed interface is planarized in the entire first region and in the entire second region. The different roughnesses in the first and second regions can be achieved by planarizing the regions to varying degrees, for example, by varying the thickness of the planarization layer, in particular the thickness of the planarization layer forming the planarization.Accordingly, when viewed from above on the main surface of the substrate, a planarization layer forming the planarization may have a different layer thickness in the entire first area than in the entire second area.

[0057] Preferably, the interface of the at least one electrode discussed above has a reflectivity of at least 50%, preferably at least 80% or even at least 90%, for electromagnetic radiation incident on the interface of the first electrode in the first and / or the second region. The reflectivities are in each case related to the radiant power. Particularly preferably, the interface in the first and / or the second region has the previously described reflectivity for one or more wavelengths of the visible light spectrum from 380 nm to 780 nm, or as the arithmetic mean over the wavelength range of visible light, or as the arithmetic mean for the entire visible light spectrum.Particularly preferably, the interface in the previously described region exhibits the previously described reflectivity for one or more wavelengths of the electromagnetic radiation generated by the functional layer structure, or relative to the total radiant power of the electromagnetic radiation generated by the functional layer structure. This allows for the realization of a highly reflective electromagnetic device, the reflection properties of which differ between the first and second regions, particularly because the first region reflects less dimly, i.e., less diffusely, compared to the second region. The reflectivity of the aforementioned interface can, in particular, relate to radiation incident perpendicular to the interface.The reflectivity of the aforementioned interface of the first electrode depends, among other things, on the refractive index of the first electrode and on the refractive index of the adjacent layer or layers.

[0058] The optoelectronic device is configured to display visible information, i.e., information visible to an external observer, through the interaction of the first and second areas. This information can be visible, for example, in both an operating and an inoperative state. The information can be, for example, at least one pattern or symbol, in particular a character.

[0059] Preferably, the optoelectronic device is configured to emit at least a portion of the generated electromagnetic radiation in one emission direction, wherein both the first region and the second region are visible when viewing the optoelectronic device against the emission direction.

[0060] This ensures that these areas are easily identifiable by an external observer. They can be visualized in an operating state of the optoelectronic device by means of a lateral variation in a property of the emitted electromagnetic radiation, e.g., a brightness distribution and / or a color distribution.

[0061] For example, the optoelectronic device can be configured to emit the portion of the generated electromagnetic radiation in the emission direction through an emission region of the second electrode. Likewise, the optoelectronic device can be configured to emit the portion of the generated electromagnetic radiation in the emission direction through an emission region of the substrate.

[0062] Preferably, the insulating layer and the planarization are in direct contact with each other, which allows for a simple design of the optoelectronic device.

[0063] The functional layer structure can be an organic functional layer structure. Preferably, the optoelectronic device is an organic light-emitting diode.

[0064] According to one embodiment, a method for providing the previously described optoelectronic device for generating electromagnetic radiation comprises the following steps: S1: Providing the substrate, S2: Provision of the insulation layer S3: Providing planarization to compensate for roughness of one of the main surfaces of the substrate facing the first electrode and the second electrode, S4: Providing the functional layer structure, the first electrode and the second electrode, wherein the first electrode is arranged on a side of the functional layer structure facing the substrate and the second electrode is arranged on a side of the functional layer structure facing away from the substrate, such that the functional layer structure is configured to generate electromagnetic radiation when the functional layer structure is energized by means of the first electrode and the second electrode. wherein in steps S2 and S4 the insulating layer and at least one of the electrodes are provided in such a way that the insulating layer electrically insulates this electrode from the substrate, in step S4, at least one electrode, which is electrically insulated from the substrate by the insulating layer, is provided as an electrode with a contact for contacting and in step S2 the insulating layer is set up and arranged to act as a moisture diffusion barrier for moisture diffusion from the contact to the planarization.

[0065] Preferably, in step S3, a liquid is applied that forms the planarization. In particular, the liquid can form a planarization consisting of a solid, for example by evaporating a solvent.

[0066] Preferably, process steps S2 and S3 are carried out after process step S1. Preferably, process steps S2 and S3 are carried out before process step S4.

[0067] Preferably, the process further comprises step S5 of providing the encapsulation layer to protect the functional layer structure from moisture. This can be carried out, for example, after process steps S1 to S4.

[0068] The principle presented here will be explained in more detail below with reference to drawings and examples. Identical reference symbols indicate identical elements in the figures. However, the references are not to scale; rather, individual elements may be exaggerated for clarity.

[0069] They show: Fig. 1A, Fig. 1B, Fig. 1C: An optoelectronic device according to the state of the art, Fig. 2a, Fig. 2b, Fig. 2c: An optoelectronic device according to a first example, Fig. 3a, Fig. 3b, Fig. 3c: An optoelectronic device according to a second example, Fig. 4a, Fig. 4b, Fig. 4c An optoelectronic device according to a first embodiment and Fig. 5a, Fig. 5b, Fig. 5c: An optoelectronic device according to a second embodiment and Fig. 6: A method for producing an optoelectronic device according to one of the embodiments.

[0070] In Fig. 1A is an optoelectronic device 10* shown in top view according to the prior art. Fig. 1B shows a cross-sectional view along line A of Fig. 1A. Fig. 1C shows section B of Fig. 1B enlarged.

[0071] The optoelectronic device 10* comprises an electrically conductive substrate 11 (in Fig. 2A not visible) with a rough surface that forms an interface with other elements of the optoelectronic device 10*. A planarization layer 12 made of an organic material is arranged on this surface, the side of which facing away from the substrate 11 has a lower roughness than the side facing the substrate 11. A first electrode 14 and a second electrode 15 are arranged on the side of the planarization layer 12 facing away from the substrate 11.

[0072] An organically functional layer structure 16 is arranged between the electrodes 14 and 15, which generates electromagnetic radiation when energized by the two electrodes 14 and 15. This radiation is emitted at least partially through the second electrode 15 by the optoelectronic device 10, but not through the substrate 11.

[0073] An encapsulation layer 17 is arranged on the aforementioned layers to protect against moisture. This layer has cutouts so that the corresponding contacts 24, 25 of the two electrodes 14, 15 are accessible. The second electrode 15 has a first section 150 made of aluminum or silver with the contact 25 and a second, translucent section 151 made of indium tin oxide. Instead of an indium tin oxide layer, any conductive transparent layer can be provided, e.g., another thin metal layer or a layer of silver nanowires.

[0074] As in Fig. As shown in Figure 1B, moisture can diffuse along moisture diffusion pathways 30 through these recesses via electrodes 14 and 15 into the organic planarization layer 12. Since the organic planarization layer 12 has a high lateral moisture transport capacity, the moisture can spread laterally via the organic planarization layer 12 towards the first electrode 14 and diffuse through the first electrode 14 into the organically functional layer structure 16, damaging it.

[0075] In Fig. 2A is an optoelectronic device 10 as shown in a first example. Fig. 2B shows a cross-sectional view along line A of Fig. 2A. Fig. 2C shows section B of Fig. 2B in magnification.

[0076] The optoelectronic device 10 comprises a planar substrate 11 (in Fig. 2A not visible), preferably made of aluminium or silver, with a rough surface which forms an interface to other elements of the optoelectronic device 10 and is referred to here and in the following as the main surface 11a.

[0077] On this main surface 11a, a planarization layer 12 made of an organic material is arranged. As will be explained in more detail later, the latter does not extend over the entire substrate 11 when viewed from above on the main surface 11a. On the planarization layer 12 and the areas of the substrate 11 not covered by it, an insulating layer 13 (in Fig. 2A (not visible) is made of an inorganic material. Viewed from above, this layer extends over the entire substrate 11, specifically over the main surface 11a. The planarization layer 12 at least partially compensates for the roughness of the substrate 11. "At least partially" means that congruent irregularities may still be present on the side of the planarization layer 12 facing away from the substrate 11, although they result in a lower degree of roughness. Accordingly, the planarization layer 12 exhibits a lower roughness on its interface 12a facing away from the substrate 11 than on its interface 12b facing the substrate 11.

[0078] On this insulating layer 13, the two electrodes 14, 15 are arranged with an intervening organic functional layer structure 16, such that the organic functional layer structure 16 generates electromagnetic radiation when energized by the two electrodes 14, 15. Finally, an encapsulation layer 17 is arranged on the aforementioned layers for protection against moisture. This layer has recesses so that corresponding contacts 24, 25 of the two electrodes 14, 15 are accessible.

[0079] In contrast to the prior art, the organic planarization layer 12, viewed from above on the main surface 11a of the substrate 11, does not extend in the area of ​​these recesses, but rather the insulating layer 13. Due to this arrangement, virtually no moisture can reach the functional layer structure 16 through the recesses and the electrodes 14, 15 via the organic planarization layer 12, in which moisture easily spreads. The insulating layer 13 acts as a moisture diffusion barrier in a direction R that runs along an interface of the insulating layer 13. However, the planarization layer 12, viewed from above on the main surface 11a of the substrate 11, extends into a region of the functional layer structure 16, so that the two electrodes 14, 15 and the functional layer structure 16 are arranged on a planar interface in this region. Consequently, for example,the first electrode 14 is produced from aluminium or silver and the functional layer structure 16 is designed such that the interface of the first electrode 14 facing away from the substrate 11 has a good reflectivity for electromagnetic radiation striking this interface from the side facing away from the substrate 11.

[0080] The insulating layer 13 consists of or comprises a non-conductive material. A non-conductive material is defined as a material with an electrical conductivity of less than 10 Ω. -8 Ω -1 ·m -1Understood. Since the insulating layer 13 extends over the entire substrate 11, the substrate 11 can still consist of an electrically conductive material without a short circuit occurring between the two electrodes 14, 15. In general, to avoid such a short circuit, it is sufficient if the insulating layer 13 is arranged in such a way that it electrically insulates at least one of the electrodes 14, 15 from the substrate 11.

[0081] The second electrode 15 comprises a first section 150 made of aluminum or silver, which has the contact area 25, and a second section 151 electrically connected to it. This second section consists of an indium tin oxide (ITO) layer that is at least partially transparent to the electromagnetic radiation generated by the functional layer structure 16, so that the generated electromagnetic radiation can be emitted through this layer by the optoelectronic device 10. This prevents damage to the ITO layer from contact. Instead of an indium tin oxide layer, any conductive transparent layer can be provided, e.g., another thin metal layer or a layer of silver nanowires.

[0082] Preferably, the insulating layer has a thickness of at least 1 µm. It can also have a thickness that is at least twice the roughness of the substrate, preferably at least twice the maximum roughness of the substrate.

[0083] In the first example described above, the insulating layer 13 is downstream of the planarization layer 12, starting from the substrate 11. This prevents diffusion of components of the organic planarization layer 12 into the organically functional layer structure 16.

[0084] Furthermore, the insulation layer 13 and the substrate 11 completely enclose the planarization layer 12, so that the planarization layer 12 is encapsulated from moisture on all sides by the insulation layer 13 in conjunction with the substrate 11.

[0085] Electrodes 14 and 15 are in direct contact with the inorganic insulating layer 13, creating a particularly stable mechanical connection. Consequently, the optoelectronic device 10 can be attached to the electrodes 14 and 15, for example by soldering or gluing them to contacts 24 and 25, or by temporarily contacting them with contact pins for measurements.

[0086] In Fig. 3A is an optoelectronic device 10 as shown in a second example. Fig. 3B shows a cross-sectional view along line A of Fig. 3A. Fig. 3C shows section B of Fig. 3B magnified.

[0087] The optoelectronic device 10 according to the second example is constructed analogously to that of the first example, with the difference that, starting from the substrate 11, the planarization layer 12 is downstream of the insulating layer 13. The planarization layer 12 downstream of the insulating layer 13 enables the simple fabrication of the insulating layer extending over the entire substrate, for example by means of a roll-to-roll process.

[0088] Fig. Figure 4A shows a sectional view of an optoelectronic device 10 according to a first embodiment. This is constructed analogously to that of the first example, with the difference that the planarization layer 12, viewed from above on the main surface 11a of the substrate 11, does not extend over the entire functional layer structure 16.

[0089] In Fig. 4C is section B of Fig. Figure 4A is shown enlarged. Since the planarization layer 12 is only present in certain areas and therefore only exerts a planarization effect in certain areas, the first electrode layer 14 on the interface 14a facing away from the substrate 11 exhibits a lower roughness in the planarized areas 34a than in the non-planarized areas 34b. In this embodiment, the metallic electrode layer 14, which in this case consists of aluminum or silver, reflects electromagnetic radiation incident from the side facing away from the substrate 11 onto its interface 14a facing away from the substrate 11 by more than 90% in both areas 34a and 34b, both averaged over the visible spectral range and averaged over the spectral range of the electromagnetic radiation that can be generated by the functional layer structure 16.

[0090] The two areas 34a and 34b generated by means of the only partially provided planarization layer 12 represent information that is visible when viewing the optoelectronic device 10 against the emission direction E in both an operating state and an out-of-service state.

[0091] The following is presented for an external observer, as in Fig. Figure 4B shows that when viewing the optoelectronic device 10 against the emission direction E in a radiation emission area 40, the hatched lettering 41 “TXT” and a hatched symbol 42 consisting of two circles, also referred to as a symbol or logo, are visible. Line AA shows the position of the section of Fig. 1A.

[0092] The planarization layer 12 is present in the entire hatched area of ​​the two circles of symbol 42 and the letters "TXT" 41 when viewed from above on the substrate 11, but not outside these areas. Accordingly, the areas 34a of the interface 14a of the first electrode layer 14, which belong to the letters 41 and the circles 42 and face away from the substrate, are planarized and reflect electromagnetic radiation incident on them in the visible spectral range and electromagnetic radiation generated by the functional layer structure 16, while the remaining area 34b of the interface 14a is dully reflective to such radiation.These different optical properties are visible to an observer looking at the optoelectronic device 10 opposite to the emission direction E, both in an operating state and in an out-of-service state, due to the corresponding different reflection of electromagnetic radiation from outside the optoelectronic device 10 onto the interface 14a and the corresponding different reflection of electromagnetic radiation that can be generated by the optoelectronic device 10.

[0093] As an alternative to signs and symbols, a pattern, i.e. a consistent structure that repeats uniformly, can also be represented using the partially applied planarization layer 12, e.g. parallel lines or a checkerboard pattern.

[0094] The in the Fig. 5A, Fig. 5B and Fig. The optoelectronic device 10 shown in Figure 5C according to a second embodiment is similar in structure to that of the first embodiment. Fig. 5A accordingly indicates a Fig. 4A analog section view, Fig. 5B one to Fig. 4B Analog representation of the characters 41, 42 and visible in the radiation emission range 40 Fig. 5C one to Fig. 4C analog enlargement of section B from Fig. 2A.

[0095] The only difference from the first embodiment is that in the second embodiment, the symbols 41 and 42 are represented by the planarization layer 12 being present in the entire area outside the two circles of symbol 42 and the letters “TXT” 41 when viewed from above on the substrate 11 (hatched area in Fig. 2B) and is not present in the area of ​​these symbols. Accordingly, for the external observer who views the optoelectronic device 10 opposite to the radiation emission direction E, the hatched area of Fig. 2B due to the reflective interface 14a of the first electrode 14, unlike the unhatched area of ​​symbols 41 and 42 due to the matte interface 14a of the first electrode 14.

[0096] In the examples and embodiments described above, the planarization layer 12 on an interface 12a facing away from the substrate 11 can have a roughness of less than or equal to 50 nm.

[0097] In the examples and embodiments described above, the planarization layer 12 consists of a different material than the insulation layer 13.

[0098] In the examples and embodiments described above, the insulating layer 13 consists of or comprises a non-conductive material.

[0099] In the examples and embodiments described above, the encapsulation layer 17 can be configured as a single layer, a stack of layers, or a layered structure. It can comprise or be composed of: aluminum oxide, zinc oxide, zirconium oxide, titanium oxide, hafnium oxide, tantalum oxide, lanthanum oxide, silicon oxide, silicon nitride, silicon oxynitride, indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, poly(p-phenylene terephthalamide), nylon 66, as well as mixtures and alloys thereof, or tetrafluoroethylene (TFE). The encapsulation layer 17 can, in particular, be a thin-film encapsulation (also known as TFE). This can, for example, consist of several individual layers produced by atomic layer deposition (ALD) or molecular layer deposition (MLD).The thin-film encapsulation or its individual layers can also be produced using ink jet printing or plasma enhanced chemical vapor deposition (PECVD) or using the so-called "vacuum polymer technology".

[0100] In the examples and embodiments described above, the planarization layer 12 can comprise an organic material selected from the following group of materials: epoxy resin, acrylate, polyurethane, polyimide, silicone, organopolysilazane, polysiloxane, styrene, polyester, polyectone. It can be printed, for example, using a method selected from the following group of printing processes: screen printing, inkjet printing, gravure printing, or flexographic printing. It can also be coated, for example, by slot-die coating or spray coating, both of which may be combined with subsequent restructuring. It can be applied in liquid form, for example, printed or coated, and subsequently cured, for example, by thermal curing or UV curing.

[0101] In the examples and embodiments described above, the insulating layer 13 can comprise an inorganic material selected from the following group of materials: oxide, nitride, oxynitride, carbide, metal oxide, metal nitride, metal oxynitride, metal carbide, ceramic, glass. In particular, the inorganic material can be silicon nitride (SiN) or silicon oxide (SiO₂). x ), silicon oxynitride (SiNO₃) x ), silicon oxycarbonitride (SiCNO₃) x ), aluminum oxide (AlO x ), titanium oxide (TiO₂) xThe insulating layer 13 can be antimony-tin oxide (ATO) or silicon carbide (SiC). This inorganic insulating layer 13 can be produced by sputtering, chemical vapor deposition, or atomic layer deposition. The insulating layer 13 can be a ceramic coating. The insulating layer 13 can also be an anodized layer, preferably on a substrate 11 containing or consisting of aluminum. It can also be a glass coating, a coating containing glass, or a glass-like coating.

[0102] The optoelectronic devices 10 according to the aforementioned examples and embodiments emit the electromagnetic radiation at least partially through the second electrode 15. Alternatively, corresponding optoelectronic devices 10 can also be provided which emit the generated electromagnetic radiation at least partially through the substrate 11, e.g., with a transparent insulating layer 13 and a transparent planarizing layer 12.

[0103] Fig.Figure 7 shows a method for producing an optoelectronic device according to one of the examples and embodiments. The method comprises the steps of providing S1 the substrate, S2 the insulating layer, S3 the planarization layer, S4 the functional layer structure, the first electrode, and the second electrode. In step S3, a liquid is applied that forms the planarization layer, which consists of a solid, by evaporating a solvent. The method may further include step S5 of providing the encapsulation layer. The method steps are performed in the following sequence: S1, S2, S3, S4, S5 (optional). Alternatively, the following sequence is also possible: S1, S3, S2, S4, S5 (optional). Reference symbol list: 10* Optoelectronic device according to the state of the art 10 Optoelectronic device 11 Substrat 11a Main surface of the substrate 12 Planarization layer 12a Interface of the planarization layer facing away from the substrate 12b Interface of the planarization layer facing the substrate 13 Insulation layer 14 First electrode 14a Interface of the first electrode facing away from the substrate 15 Second electrode 150 First section of the second electrode 151 Second section of the second electrode 16 Functional layer structure 17 Encapsulation layer 24 Contact first electrode 25 Contact second electrode 30 Moisture diffusion pathway 34a First area of ​​the first electrode 34b Second area of ​​the first electrode 40 Emission area 41 characters 42 characters A line B section R direction, which runs in the main surface of the substrate E Emission direction

Claims

[1] Optoelectronic device (10) for generating electromagnetic radiation, comprising: a substrate (11), a functional layer structure (16), a first electrode (14) arranged on a side of the functional layer structure (16) facing the substrate (11) and a second electrode (15) arranged on a side of the functional layer structure (16) facing away from the substrate (11), wherein the functional layer structure (16) is configured to generate electromagnetic radiation when the functional layer structure (16) is energized by means of the first electrode (14) and the second electrode (15), an insulating layer (13) which electrically insulates at least one of the electrodes (14, 15) from the substrate (11), wherein the at least one electrode which is electrically insulated from the substrate (11) by the insulating layer (13) has a contact (24, 25) for contacting, a planarization (12) to compensate for a roughness of one of the main surfaces (11a) of the substrate (11) facing the first electrode (14) and the second electrode (15), and an encapsulation layer (17) to protect the functional layer structure (16) from moisture, which has a recess that makes the contact (24, 25) accessible for contacting, wherein the insulating layer (13) is set up and arranged to act as a moisture diffusion barrier for moisture diffusion from the contact (24, 25) to the planarization (12), where the planarization (12) as seen from above on the main surface (11a) of the substrate (11) does not overlap with the contact (24, 25), where, viewed from above on the main surface of the substrate (11), the planarization (12) and the recess do not overlap, wherein the planarization (12) is designed and arranged such that at least one of the first and second electrodes (14) has an interface (14a) which has a lower roughness in at least a first region (34a) than in a second region (34b), and wherein the optoelectronic device is configured to display information visible to an external observer by the interaction of the first area (34a) and the second area (34b). [2] Optoelectronic device according to claim 1, wherein the first electrode (14), the second electrode (15), the functional layer structure (16), the insulating layer (13), the planarization (12) and the contact (24, 25) are arranged at least partially on the main surface (11a) of the substrate (11). [3] Optoelectronic device according to one of the preceding claims, wherein the insulating layer (13) extends over the entire contact (24, 25) in a top view of the main surface (11a) of the substrate (11). [4] Optoelectronic device (10) according to one of the preceding claims, wherein an interface of the first electrode (14) facing away from the substrate (11) or an interface of the second electrode (15) facing the substrate (11) has a reflectivity of at least 50% for electromagnetic radiation incident on the interface in a region which is planarized by the planarization (12). [5] Optoelectronic device (10) according to one of the preceding claims, wherein the insulating layer (13) and the substrate (11) together completely enclose the planarization (12). [6] Optoelectronic device (10) according to one of the preceding claims, wherein a roughness of an interface (12a) facing away from the substrate (11) of the planarization (12) is less than or equal to 200 nm. [7] Optoelectronic device (10) according to one of the preceding claims, wherein the insulating layer (13) has a thickness of at least 1 µm. [8] Optoelectronic device (10) according to any of the preceding claims, wherein the planarization (12) comprises an organic material. [9] Optoelectronic device (10) according to one of the preceding claims, wherein the insulating layer (13) comprises an inorganic material. [10] Method for providing an optoelectronic device (10) for generating electromagnetic radiation, comprising: Providing (S1) a substrate (11), Providing (S2) an insulating layer (13), Providing (S3) a planarization (12) to compensate for a roughness of one of the main surfaces (11a) of the substrate (11) facing the first electrode (14) and the second electrode (15), Providing (S4) a functional layer structure (16), a first electrode (14) and a second electrode (15), wherein the first electrode (14) is arranged on a side of the functional layer structure (16) facing the substrate (11) and the second electrode is arranged on a side of the functional layer structure (16) facing away from the substrate (11), such that the functional layer structure (16) is configured to generate electromagnetic radiation when the functional layer structure (16) is energized by means of the first electrode (14) and the second electrode (15), wherein the insulating layer (13) and at least one of the electrodes (14, 15) are provided (S2, S4) such that the insulating layer (13) electrically insulates this electrode (14, 15) from the substrate (11), wherein at least one electrode (14, 15) which is electrically insulated from the substrate (11) by the insulating layer (13) is provided as an electrode (14, 15) with a contact (24, 25) for contacting (S4) and wherein when providing (S2) the insulating layer (13) it is set up and arranged to act as a moisture diffusion barrier for moisture diffusion from the contact (24, 25) to the planarization (12), where the planarization (12) as seen from above on the main surface (11a) of the substrate (11) does not overlap with the contact (24, 25), wherein the optoelectronic device (10) comprises an encapsulation layer (17) for protecting the functional layer structure (16) from moisture, which has a recess that makes the contact (24, 25) accessible for contacting, where, viewed from above on the main surface of the substrate (11), the planarization (12) and the recess do not overlap, and wherein the planarization (12) is designed and arranged such that at least one of the first and second electrodes (14) has an interface (14a) which has a lower roughness in at least a first region (34a) than in a second region (34b), and wherein the optoelectronic device is configured to display information visible to an external observer by the interaction of the first area (34a) and the second area (34b). [11] Method according to claim 10, wherein, during the provision (S3) of the planarization (12), a liquid is applied which forms the planarization (12). [12] Method according to claim 10 or 11, wherein an optoelectronic device (10) according to any one of claims 2 to 9 is produced.

Images