Optoelectronic device

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), and 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), wherein the planarization (12) is designed and arranged such that at least one of the first and second electrodes (14, 15) has an interface (14a, 15b) which has a lower roughness in at least a first region (34a, 35a) than in a second region (34b, 35b).

Description

[0001] The invention relates to an optoelectronic device for generating electromagnetic radiation.

[0002] The following publications describe optoelectronic devices: US 9 231 154 B2, CH 709 370 A1, DE 10 2012 200 084 A1, DE 10 2013 111 785 A1, US 2011 / 0 250 392 A1.

[0003] It is known to arrange a planarization between the substrate and an electrode in optoelectronic devices for generating electromagnetic radiation, thereby compensating for a roughness of the substrate.

[0004] The object of the present invention is to improve the appearance of such an optoelectronic device.

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

[0006] The 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, a second electrode arranged on a side of the functional layer structure facing away from the substrate, and a planarization system for compensating for roughness on a main surface of the substrate facing the electrodes. The functional layer structure is configured to generate electromagnetic radiation when the functional layer structure is energized by means of the first and second electrodes. The planarization system is designed and arranged such that at least one of the first and second electrodes has an interface that exhibits lower roughness in at least a first region than in a second region.

[0007] Planarization can refer in particular to a planarization layer.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] The planarization is preferably arranged between the substrate and the first electrode. This allows for a simple design of the optoelectronic device.

[0012] 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.

[0013] 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.

[0014] In a preferred embodiment, the first electrode, the second electrode, the functional layer structure, and the planarization are 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.

[0015] 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.

[0016] 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.

[0017] According to a preferred embodiment, the planarization is designed and arranged such that the previously discussed interface is planarized by the planarization in the entire first region and not planarized by the planarization in 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 the planarization, and the same roughness in the second region as it would have without the planarization. The planarization can include at least one recess that creates the second region. This recess can be completely surrounded by the planarization.

[0018] 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.

[0019] 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.

[0020] The planarization results in 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.

[0021] The average roughness of a reference area, represented by the symbol R a The mean roughness (R) represents the average distance of all points on the surface or interface within the reference area to a mean plane. The mean plane intersects the actual profile such that the mean distance is minimized. aThis corresponds to the arithmetic mean of the absolute deviation from the mean plane.

[0022] 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.

[0023] 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.

[0024] 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 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.The interface in the previously described area also preferably exhibits the previously described reflectivity for one or more wavelengths of the electromagnetic radiation that can be generated by the functional layer structure, or in relation to the total radiant power for the electromagnetic radiation that can be generated by the functional layer structure.

[0025] This allows for the realization of a highly reflective electromagnetic device, where the reflection properties 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 relate specifically 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 the refractive index of the adjacent layer(s).

[0026] Preferably, 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 regions. This information can be visible, for example, in both an operating and an out-of-service state. The information can be, for example, at least one pattern or one character, in particular a character.

[0027] 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.

[0028] Planarization can be planarization processed from the liquid phase, i.e., a liquid was applied to provide the planarization, which forms the planarization.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] According to one embodiment, the planarization electrically isolates 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.

[0033] Preferably, in addition to the planarization, the optoelectronic device comprises 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.

[0034] Preferably, the first electrode, the second electrode, the functional layer structure, the planarization and the insulating layer are arranged at least partially on the main surface of the substrate.

[0035] According to a preferred embodiment, the electrode, which is electrically insulated from the substrate by the insulating layer, comprises a contact for contacting, wherein the insulating layer is designed and arranged to act as a moisture diffusion barrier to prevent moisture diffusion from the contact to the planar surface. The contact preferably serves for external contacting, i.e., contacting from outside the optoelectronic device. The contact can be formed by a contactable area on one of the two electrodes.

[0036] This allows the use of a planar structure, in which moisture spreads easily, while maintaining a robust design. For example, moisture can spread easily in an organic planar structure.

[0037] Preferably, the first electrode, the second electrode, the functional layer structure, the planarization, the insulating layer and the contact are arranged at least partially on the main surface of the substrate.

[0038] 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.

[0039] Ideally, the insulation layer and the substrate together completely enclose the planarization. This allows the insulation layer, in conjunction with the substrate, to completely encapsulate the planarization from moisture on all sides.

[0040] According to an alternative embodiment, the planarization of the insulating layer is a subsequent step, starting from the substrate. The insulating layer can extend over 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 is applied and finely structured. The planarization is preferably arranged such that at least a portion of the contact is not planarized. This facilitates the moisture diffusion barrier effect of the insulating layer. It is particularly preferred that the entire contact is not planarized.

[0041] 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, preferably, 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 allows for a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0042] 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.

[0043] Preferably, the insulating layer is designed and arranged to act as a moisture diffusion barrier in the lateral direction. This allows for a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0044] 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.

[0045] A lateral direction of the insulation layer is understood, for example, to be a direction running in an interface of a planar insulation layer neglecting surface roughness, or, for example, a tangent to an interface of a curved insulation layer neglecting surface roughness.

[0046] Accordingly, a top view of the main surface of the substrate is understood to mean, for example, a perpendicular projection onto the main surface of a flat substrate or, for example, 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.

[0047] Preferably, the optoelectronic device also comprises an encapsulation layer to protect the functional layer structure from moisture, which has a recess that makes the contact accessible for contacting, e.g. for external contacting.

[0048] 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).

[0049] 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.

[0050] 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.

[0051] Preferably, when viewed from above on the main surface of the substrate, the planarization and the recess overlap only partially or, even better, not at all. In other words, preferably, when viewed from above on the main surface of the substrate, the planarization does not extend over a certain area of ​​the recess, and particularly preferably, when viewed from above on the main surface of the substrate, the planarization does not extend over the entire recess. This allows for a simple design of the optoelectronic device with good moisture diffusion barrier properties of the insulating layer.

[0052] 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.

[0053] 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.

[0054] 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. Consequently, it is possible to attach the optoelectronic device 10 to the electrodes 14, 15.

[0055] 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), silicon carbide (SiC).

[0056] Preferably, the insulating layer and the planarization are in direct contact with each other, which allows for a simple design of the optoelectronic device.

[0057] The layer structure can be an organically functional layer structure. Preferably, the optoelectronic device is an organic light-emitting diode.

[0058] According to one embodiment, a method for providing the previously described optoelectronic device for generating electromagnetic radiation comprises the steps: S1: Providing the substrate, 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 a functional layer structure, a first electrode and a 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 step S3 the planarization is designed and arranged such that in step S4 at least one of the first and second electrodes forms an interface which has a lower roughness in at least a first region than in a second region.

[0059] 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.

[0060] Preferably, process step S3 is performed after process step S1. Preferably, process step S3 is performed before process step S4.

[0061] Preferably, the method further comprises step S2 of providing the insulating layer, wherein in steps S2 and S4 the insulating layer and at least one of the electrodes are provided such that the insulating layer electrically insulates this electrode from the substrate, wherein in step S4 the 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 wherein 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] They show: Fig. 1A, Fig. 1B and Fig. 1C: An optoelectronic device according to a first embodiment, Fig. 2A, Fig. 2B and Fig. 2C: An optoelectronic device according to a second embodiment, Fig. 3A and Fig. 3B: An optoelectronic device according to a third embodiment, Fig. 4A and Fig. 4B: An optoelectronic device according to a fourth embodiment, Fig. 5A and Fig. 5B: An optoelectronic device according to a fifth embodiment, Fig. 6A and Fig. 6B: An optoelectronic device according to a sixth embodiment, Fig. 7: a method for producing an optoelectronic device according to one of the embodiments, and Fig. 8A and Fig. 8B: An optoelectronic device in accordance with the state of the art.

[0066] Fig. Figure 1A shows a sectional view of an optoelectronic device 10 according to a first embodiment. This device comprises an electrically non-conductive substrate 11 with a rough surface, which forms an interface with other elements of the optoelectronic device 10 and is referred to here and in the following as the main surface 11a. A planarization layer 12 made of an organic material is arranged on this surface in certain areas. The planarization layer 12 at least partially compensates for roughness in 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 roughness. Accordingly, the planarization layer 12 has a lower roughness on its interface 12a facing away from the substrate 11 than on its interface 12b facing the substrate 11.Above the planarization layer 12, a first electrode 14, consisting of a first electrode layer, is arranged, followed by an organic functional layer structure 16 and a second electrode layer, which forms a second section 151 of a second electrode 15. When energized by the two electrodes 14 and 15, the organic functional layer structure 16 generates electromagnetic radiation and emits it through the transparent second electrode layer (second section 151 of the second electrode 15) made of indium tin oxide in an emission direction E. Instead of an indium tin oxide layer, any conductive transparent layer can be used, e.g., another thin metal layer or a layer of Ag nanowires. The first electrode 14 is made of aluminum, which can be directly contacted without potentially damaging it.The second electrode layer (second section 151 of the second electrode 15) made of indium tin oxide is electrically connected to another electrode element made of aluminum, which represents a first section 150 of the second electrode 15, which can be contacted without possibly damaging it, in order to indirectly contact the sensitive second electrode layer (second section 151 of the second electrode 15) made of indium tin oxide.

[0067] In Fig. 1C is section B of Fig. Figure 1A 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. The metallic electrode layer 14, which in this case consists of aluminum, reflects electromagnetic radiation incident from the side facing away from the substrate 11 onto its interface 14a facing away from the substrate 11 by over 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.

[0068] 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.

[0069] The following is presented for an external observer, as in Fig. Figure 1B 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 indicates the position of the section of Fig. 1A.

[0070] 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 in the opposite direction of emission 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 and the corresponding different reflection of electromagnetic radiation generated by the optoelectronic device 10.

[0071] 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.

[0072] The in the Fig. 2A, Fig. 2B and Fig. The optoelectronic device 10 shown in Figure 2C according to a second embodiment is similar in structure to that of the first embodiment. Fig. 2A accordingly shows a Fig. 1A analog section view, Fig. 2B one to Fig. 1B Analog representation of the characters 41, 42 and visible in the radiation emission range 40 Fig. 2C one to Fig. 1C analog enlargement of section B from Fig. 2A.

[0073] 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.

[0074] The in the Fig. 3A, Fig. 3B and Fig. The optoelectronic device 10 shown in Figure 3C according to a third embodiment is similar in structure to that of the first embodiment. Fig. 3A accordingly shows a Fig. 1A analog section view, Fig. 3B one to Fig. 1B Analog representation of the characters 41, 42 and visible in the radiation emission range 40 Fig. 3C one to Fig. 3C analog magnification of section B of Fig. 2A.

[0075] The difference from the first embodiment is that, in the optoelectronic device 10 according to the third embodiment, the generated electromagnetic radiation is emitted in an emission direction E through the first electrode 14, the planarization layer 12, and the substrate 11. The transparent first electrode 14 can, for example, consist of indium tin oxide, and the substrate 11 can be a plastic film. A thin-film encapsulation (not shown) can be arranged over the substrate 11 and the planarization layer 12, on which the first electrode 14 is again arranged.

[0076] As in Fig. As can be seen in Figure 3C, the planarization layer 12 only exerts a planarization effect in certain areas, so that the second electrode layer 15 on an interface 15b facing the substrate 11 exhibits a lower roughness in the planarized areas 35a than in the non-planarized areas 35b. The metallic electrode layer 15, which in this case consists of aluminum, reflects electromagnetic radiation incident on its interface 14a facing the substrate 11 in both areas 35a and 35b by over 90%, 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.

[0077] Analogous to the first embodiment, the two areas 35a and 35b 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 both in an operating state and in an out-of-service state.

[0078] The in the Fig. 4A and Fig. The optoelectronic device 10 shown in Figure 4B according to a fourth embodiment is similar in structure to that of the first embodiment. Fig. 4A shows one to Fig. 1A analog section view and Fig. 4B one to Fig. 1C analog enlargement of section B from Fig. 4A.

[0079] The only difference from the first embodiment is that in the fourth embodiment, the substrate 11 is electrically conductive. For example, it can be made of aluminum or silver. Accordingly, an inorganic insulating layer 13 is arranged directly over the substrate 11, extending over the entire main surface 11a of the substrate 11 and thus electrically insulating the substrate 11 from the two electrodes 14 and 15. The insulating layer 13 consists of an inorganic material and has only a very low planarizing effect. 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.

[0080] The electrodes 14, 15 are in direct contact with the inorganic insulating layer 13, thereby creating a particularly stable mechanical connection with the electrodes 14, 15. Consequently, it is possible to attach the optoelectronic device 10 to the electrodes 14, 15, e.g. by soldering or gluing them on, or by temporarily contacting them with contact pins for measurements.

[0081] 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.

[0082] The in the Fig. 5A and Fig. The optoelectronic device 10 shown in Figure 5B according to a fifth embodiment is similar in structure to that of the fourth embodiment. Fig. 5A shows a Fig. 4A analog section view and Fig. 5B one to Fig. 4B analog enlargement of section B of Fig. 5A.

[0083] The only difference from the fourth embodiment is that in the fifth embodiment, the partial planarization layer 12 is arranged directly on the substrate 11, and the insulating layer 13 extends over it. This prevents diffusion of components of the organic planarization layer 12 into the organically functional layer structure 16.

[0084] 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] In contrast, the planarization layer 12 downstream of the insulating layer 13 in the optoelectronic device 10 according to the fourth embodiment enables a simple production of the insulating layer extending over the entire substrate, for example by means of a roll-to-roll process.

[0086] The in the Fig. 6A and Fig. The optoelectronic device 10 shown in Figure 6B according to a sixth embodiment is similar in structure to that of the fifth embodiment. Fig. 6B shows a top view and Fig. 6A shows a Fig. 5A analog section view along line AA of Fig. 6A.

[0087] In contrast to the fifth embodiment, the sixth embodiment also includes an encapsulation layer 17 for protection against moisture. This layer has recesses so that the corresponding contacts 24, 25 of the two electrodes 14, 15 are accessible.

[0088] In this arrangement, the organic planarization layer 12, viewed from above on the main surface 11a of the substrate 11, does not extend into the area of ​​these recesses, but only 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, viewed from above on the main surface 11a of the substrate 11, the planarization layer 12 extends in the same manner as in the first, fourth, and fifth embodiments into a region of the functional layer structure 16, thus representing figures 41 and 42.

[0089] As an alternative to the insulation layer 13 being subordinate to the planarization layer 12, the planarization layer 12 can also be subordinate to the insulation layer 13 (analogous to the fourth embodiment).

[0090] The optoelectronic devices 10 according to the fourth, fifth, and sixth embodiments emit the electromagnetic radiation at least partially through the second electrode 15. Alternatively, corresponding optoelectronic devices 10 can also be provided which, analogous to the third embodiment, emit the generated electromagnetic radiation at least partially through the substrate 11, e.g., with a transparent planarization layer 12 and a transparent insulating layer 13.

[0091] In the 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.

[0092] In the embodiments described above, the planarization layer 12 consists of a different material than the insulation layer 13.

[0093] In the embodiments described above, the insulating layer 13 (if present) consists of or comprises a non-conductive material.

[0094] In the embodiments described above, the encapsulation layer 17 (if present) 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 referred to 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".

[0095] In the embodiments described above, the planarization layer 12 (if present) 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 optionally in combination 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.

[0096] In the 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.

[0097] Fig. Figure 7 shows a method for producing an optoelectronic device according to one of the embodiments. The method comprises the steps of providing S1 the substrate, 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, which consists of a solid, by evaporating a solvent. The method may further include step S2 of providing the insulating layer. Additionally, the method may include step S5 of providing the encapsulation layer. The method steps are performed in the following sequence: S1, S2 (optional), S3, S4, S5 (optional). Alternatively, the following sequence is also possible: S1, S3, S2 (optional), S4, S5 (optional).

[0098] In Fig. 8A is an optoelectronic device 10* shown in top view according to the prior art. Fig. Figure 8B shows a cross-sectional view along line A of Fig. 8A.

[0099] The optoelectronic device 10* comprises an electrically conductive substrate 11 (in Fig. 8A 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.

[0100] 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.

[0101] An encapsulation layer 17 is arranged on the aforementioned layers to protect against moisture. This layer has recesses 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 with the contact 25 and a second, translucent section 151 made of indium tin oxide.

[0102] As in Fig.As shown in Figure 8B, 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 towards the first electrode 14 and diffuse through the first electrode 14 into the organic functional layer structure 16, damaging it. Reference symbol list: 10 Optoelectronic device 10* Optoelectronic device according to the state of the art 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 15b Interface of the second electrode facing the substrate 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 35a First area of ​​the second electrode 35b Second area of ​​the second electrode 40 emission range 41 characters 42 characters A line B section R direction, which runs in the main area 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), and 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), wherein the planarization (12) is designed and arranged such that at least one of the first and second electrodes (14, 15) has an interface (14a, 15b) which has a lower roughness in at least a first region (34a, 35a) than in a second region (34b, 35b). [2] Optoelectronic device (10) according to claim 1, wherein the interface (14a, 15b) of the electrode (14, 15) is planarized by the planarization (12) in the entire first region (34a) and is not planarized by the planarization (12) in the entire second region (34b). [3] 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 500 nm. [4] Optoelectronic device (10) according to one of the preceding claims, wherein the roughness of the main surface (11a) of the substrate (11) is greater than or equal to 500 nm. [5] Optoelectronic device (10) according to one of the preceding claims, wherein an interface (12a) of the planarization (12) facing away from the substrate (11) has a roughness that is 5 times lower than an interface (12b) of the planarization (12) facing the substrate (11). [6] Optoelectronic device (10) according to one of the preceding claims, wherein the interface (14a, 15b) of the electrode (14, 15) has a reflectivity of at least 50% for electromagnetic radiation incident on the interface (14a, 15b) in the first region (34a, 35a) or in the second region (34b, 35b) or both in the first region (34a, 35a) and in the second region (34b, 35b). [7] Optoelectronic device (10) according to one of the preceding claims, wherein the optoelectronic device (10) is configured to display visible information in an operating state and in an out-of-service state by the interaction of the first area (34a) and the second area (34b). [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 claim 8, wherein the planarization (12) comprises an organic material selected from the following group of materials: Epoxy resin, acrylate, polyurethane, polyimide, silicone, organopolysilazane, polysiloxane, styrene, polyester, polyectone. [10] Optoelectronic device (10) according to one of the preceding claims, wherein the optoelectronic device (10) is configured to emit at least a part of the generated electromagnetic radiation in an emission direction (E), wherein both the first region (34a, 35a) and the second region (34b, 35b) are visible when viewing the optoelectronic device (10) against the emission direction (E). [11] Optoelectronic device (10) according to one of the preceding claims, comprising an insulating layer (13) which electrically insulates at least one of the first and second electrodes (14, 15) from the substrate (11). [12] Optoelectronic device according to claim 11, wherein the electrode, which is electrically insulated from the substrate (11) by the insulating layer (13), has a contact (24, 25) for contacting and 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). [13] Method for manufacturing an optoelectronic device (10) for generating electromagnetic radiation, comprising: Providing (S1) a substrate (11), 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 (15) 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, when providing (S3) the planarization (12), it is designed and arranged such that, when providing (S4) the first and second electrodes (14, 15), at least one of the first and second electrodes (14, 15) forms an interface (14a, 15b) which has a lower roughness in at least a first region (34a, 35a) than in a second region (34b, 35b). [14] Method according to claim 13, wherein in the step (S3) of providing the planarization (12) a liquid is applied which forms the planarization (12). [15] Method according to claim 13 or 14, wherein an optoelectronic device (10) according to any one of claims 2 to 12 is produced.

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