Radiation-emitting device and method for its manufacture

Abstract

Radiation-emitting device (600) comprising: - a substrate (100), - at least one inner optoelectronic component (300) and at least one outer optoelectronic component (200) which at least partially encloses the inner optoelectronic component laterally, wherein each of the optoelectronic components comprises a layer sequence suitable for generating electromagnetic radiation with at least one first electrode surface (211, 311), at least one second electrode surface (212, 312) and at least one functional layer (213, 313) between the first electrode surface and the second electrode surface, wherein the functional layer is suitable for generating electromagnetic radiation in an switched-on operating state, and - a cover element (500) which is arranged on the optoelectronic components (200, 300) and comprises at least one first contact element (521).which comprises the first electrode surface (311) of the inner optoelectronic component, and at least one second contact element (522) which is electrically conductively connected to the second electrode surface (312) of the inner optoelectronic component, wherein each of the contact elements (521, 522) extends to an edge of the radiation-emitting device, wherein the contact elements (521, 522) are each electrically conductively connected to inner contact structures (321, 322) which are arranged at an edge of the inner optoelectronic component and are electrically conductively connected to the electrode surfaces (311, 312) of the inner optoelectronic component, wherein an electrically non-conductive adhesive (16) is applied to the first contact element (521) and to the second contact element (522) except for two areas (531, 532) in which contacting of the inner contact structures takes place.

Description

A radiation emitting device and a method for manufacturing the same are provided.Radiation-emitting devices, in particular those which comprise organic light-emitting diodes (OLEDs), are suitable as large-area, thin light-emitting elements. In many applications it is desirable for electromagnetic radiation to be emitted over two luminous surfaces, one of which laterally encloses the other. In particular, it may be desirable to form the intermediate region between the two luminous surfaces transparent.One solution known from the prior art consists in contacting the inner light-emitting element across the intermediate region at the level of the light-emitting elements. A disadvantage of this solution is that the connection structures required for this purpose are generally not transparent and have a visually disturbing effect in the intermediate region between the luminous surfaces.The document WO 2013 / 061197 A1 discloses an improved masking for light-emitting component structures. The publication WO 2012 / 049580 A1 describes a multi-component OLED. The document DE 11 2012 004 123 T5 relates to a light emission device.At least one object of certain embodiments is to provide a radiation-emitting device which has an inner luminous surface and an outer luminous surface enclosing the inner luminous surface and which does not rely on visually disturbing elements in the region between the two luminous surfaces.This object is achieved by a radiation-emitting device according to the invention according to claim 1 and a method according to the invention according to claim 10.Advantageous embodiments and developments of the subject matter and of the method are characterized in the dependent claims and are furthermore evident from the following description and the drawings.According to at least one embodiment of the radiation-emitting device, a radiation-emitting device comprises a substrate, at least one inner optoelectronic component arranged on the substrate and at least one outer optoelectronic component arranged on the substrate.The fact that a layer or an element is arranged or applied "on" or "over" another layer or another element or else "between" two other layers or elements can mean here and below that the one layer or the one element is arranged directly in direct mechanical and / or electrical contact on the other layer or the other element. Furthermore, it can also mean that the one layer or the one element is arranged indirectly on or above the other layer or the other element. In this case, further layers and / or elements can then be arranged between the one and the other layer or the one and the other element.According to at least one embodiment of the radiation-emitting device, the outer optoelectronic component laterally encloses the inner optoelectronic component at least partially.A lateral (lateral) direction is understood in particular to mean a direction parallel to a main extension plane of the substrate and / or at least one of the light-emitting layers of the radiation-emitting device. Analogously, a vertical direction is understood to mean, in particular, a direction perpendicular to a main plane of extent of the substrate and / or of one of the light-emitting layers.Each of the optoelectronic components comprises a layer sequence suitable for generating electromagnetic radiation, having at least one first electrode surface, at least one second electrode surface and at least one functional layer between the first electrode surface and the second electrode surface. The functional layer is suitable for generating electromagnetic radiation in a switched-on operating state.According to at least one embodiment, the radiation-emitting device comprises a cover element which is arranged on the optoelectronic components. The optoelectronic components are thus arranged between the substrate and the cover element, wherein the substrate and / or the cover element can be configured to protect the optoelectronic components from moisture and / or oxygen. The cover element comprises, for example, a cover carrier, which preferably consists of glass or a polymer or contains one of these materials. Furthermore, an additional thin-film encapsulation layer can be provided between the optoelectronic components and the cover element.According to at least one embodiment, the cover element comprises at least one first contact element which is electrically conductively connected (indirectly or directly) to the first electrode surface of the inner optoelectronic component, and at least one second contact element which is electrically conductively connected (indirectly or directly) to the second electrode surface of the inner optoelectronic component.Due to the fact that the cover element has contact elements, by means of which contact is made with the electrode surfaces of the inner optoelectronic component, it is not necessary to provide visually disturbing connection structures on the plane of the optoelectronic components in an intermediate region between the outer and the inner optoelectronic component. Rather, the inner optoelectronic component is contacted across the plane of the cover element. The contact elements, which are typically transparent, ensure that the intermediate region between the outer and the inner optoelectronic component can also be transparent overall.Here and in the following, "translucent" denotes a layer which is transmissive for visible light. The translucent layer can be transparent, i.e. clearly translucent, or at least partially light-scattering and / or partially light-absorbing, so that the translucent layer can also be diffuse or milky translucent, for example. Particularly preferably, a layer referred to here as translucent is formed as transparent as possible, so that in particular the absorption of light is as low as possible.According to at least one embodiment of the radiation-emitting device, it is provided that the layer sequence of the optoelectronic components each comprises an organic functional layer, in particular an organic electroluminescent layer. The optoelectronic components are thus embodied as OLEDs.The functional layers can comprise, in particular, an organic functional layer stack having an organic electroluminescent layer. The organic functional layer stack can have, for example, a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and / or an electron injection layer, which are suitable for conducting holes or electrons to the organic electroluminescent layer or for blocking the respective transport. Suitable layer structures for the organic functional layer stack are known to the person skilled in the art and are therefore not explained here in any further detail.According to at least one embodiment of the radiation-emitting device, it is provided that a length and / or a width of the inner optoelectronic component is between 1 cm and 10 cm, preferably between 2 cm and 5 cm.According to at least one embodiment of the radiation-emitting device, it is provided that a length and / or a width of the outer optoelectronic component is between 2 cm and 30 cm, preferably between 5 cm and 20 cm.According to at least one embodiment of the radiation-emitting device, it is provided that the first electrode(s) and / or second electrode(s) surface(s) of the inner and / or outer optoelectronic component is(are) formed translucent, in particular transparent. The electrode area(s) of the inner and / or outer optoelectronic component, which is (are) arranged between the functional layers and the substrate, is preferably (are) transparent, such that light emitted from the functional layers can be emitted through the electrode areas and the substrate.The transparently formed electrode surfaces preferably comprise a transparent conductive oxide (TCO). Transparent conductive oxides are transparent conductive materials, generally metal oxides, such as, for example, zinc oxide, tin oxide, cadmium oxide, titanium oxide, indium oxide or indium tin oxide (ITO).The electrode surface(s) of the inner and / or outer optoelectronic component which is (are) arranged between the functional layers and the cover element can likewise be transparent, such that light emitted from the functional layers can be emitted through the electrode surfaces and the cover element. Alternatively, the electrode surface(s) of the inner and / or outer optoelectronic component, which is(are) arranged between the functional layers and the cover element, can (can) be formed to be reflective.According to at least one embodiment of the radiation-emitting device, it is provided that the substrate is formed to be translucent, in particular transparent. In this case, a radiation exit surface of the radiation-emitting device can be formed by the substrate. The substrate preferably consists of glass or a polymer or contains one of these materials.According to at least one embodiment of the radiation-emitting device, it is provided that the cover element is formed to be translucent, in particular transparent. In this case, a radiation exit surface of the radiation-emitting device can be formed by the cover element. The cover element preferably comprises a cover carrier which consists of glass or a polymer or contains one of these materials and on which the translucent contact elements are arranged.According to at least one embodiment of the radiation-emitting device, it is provided that the contact elements comprise a transparent conductive oxide, for example indium tin oxide, or consist of a transparent conductive oxide, for example indium tin oxide. Each of the contact elements extends in each case as far as a lateral edge of the radiation-emitting device.According to at least one embodiment of the radiation-emitting device, it is provided that an intermediate region between the inner optoelectronic component and the outer optoelectronic component is formed to be translucent, in particular transparent.According to at least one embodiment of the radiation-emitting device, it is provided that the contact elements are each electrically conductively connected to contact structures which are arranged on an edge of the inner optoelectronic component and are electrically conductively connected to the electrode surfaces of the inner optoelectronic component.According to at least one embodiment of the radiation-emitting device, it is provided that the contact elements are fastened to the contact structures via a conductive adhesive.According to at least one embodiment of the radiation-emitting device, the contact elements are connected to the contact structures via recesses in a thin-film encapsulation layer which is arranged at least over the layer sequence of the inner optoelectronic component. This protects the layer sequence of the inner optoelectronic component from moisture and atmospheric oxygen. The thin-film encapsulation layer can also cover the layer sequence of the outer optoelectronic component and extend, for example, as a continuous layer over the two optoelectronic components and the intermediate region formed between them.According to at least one embodiment of the radiation-emitting device, it is provided that the outer optoelectronic component completely laterally encloses the inner optoelectronic component. For example, the outer optoelectronic component can be arranged annularly around the inner optoelectronic component. A ring-shaped arrangement is understood here to mean both a circular arrangement and an arrangement having a more general ring shape, for example in rectangles or squares, around the centers of which the optoelectronic components are arranged. The outer optoelectronic component and the inner optoelectronic component are preferably arranged concentrically with respect to one another.According to at least one embodiment of the radiation-emitting device, it is provided that the contact elements are of strip-shaped design.According to at least one embodiment of the radiation-emitting device, it is provided that the cover element protrudes beyond the substrate in the preferred direction. In the region not covered by the substrate, the contact elements of the cover element can easily be contacted from the outside. Preferably, the region of the cover element not covered by the substrate forms a contact strip which can be inserted, for example, into a corresponding separate holder, by means of which the inner optoelectronic component can be supplied with electrical energy. The outer optoelectronic component can be contacted, for example, via a further, spatially spaced contacting strip. The contact strips are preferably formed by severing the production substrate having a multiplicity of radiation-emitting devices produced side by side, for example by scribing and breaking along suitable lines.A further aspect of the invention relates to a method for producing a radiation-emitting device which is constructed as described above.According to at least one embodiment, the method comprises the following method steps:providing a substrate and at least two optoelectronic components arranged on the substrate, wherein an outer optoelectronic component at least partially laterally encloses at least one inner optoelectronic component;providing a cover element, wherein the cover element comprises a cover carrier and at least a first and a second contact element on a main surface of the cover carrier; andfastening the cover element to the optoelectronic components, wherein the first contact element is electrically conductively connected to the first electrode surface of the inner optoelectronic component and the second contact element is electrically conductively connected to the second electrode surface of the inner optoelectronic component. For example, the cover element can be adhesively bonded to the optoelectronic components.According to at least one embodiment of the method, the contact elements are fastened via a conductive adhesive to contact structures which are arranged on an edge of the inner optoelectronic component and are electrically conductively connected to the electrode surfaces of the inner optoelectronic component. Preferably, the contact structures are at least partially exposed using laser ablation. The diameter of the laser beam used for this purpose is preferably between 25 μm and 100 μm, particularly preferably 60 μm or less. The laser may be a diode-pumped solid-state laser. The laser can generate laser radiation in the UV range, for example with a wavelength of 370 nm. The power of the laser can be, for example, between 1 W and 4 W.According to at least one embodiment of the method, the contact elements are structured using laser ablation. Preferably, the contact elements of the cover element are produced by laser structuring a layer of a transparent conductive oxide on one of the main surfaces of the cover carrier.Further advantages, advantageous embodiments and refinements emerge from the exemplary embodiments described below in conjunction with the figures.The following are shown: FIGS. 1 to 9 show a method for producing a radiation-emitting device according to the invention according to a first exemplary embodiment, and FIGS. 10 and 11 show schematic sectional views of the radiation-emitting device.In the exemplary embodiments and figures, identical, identical or identically acting elements can each be provided with the same reference numerals. The elements shown and their size relationships to one another are not to be regarded as being to scale; rather, individual elements, such as layers, components, components and regions, may be represented disproportionately large for better representability and / or for better understanding; this may relate to individual dimensions or to all dimensions of the elements.FIGS. 1 to 9 show a method for producing a radiation-emitting device according to the invention in accordance with a first exemplary embodiment.In a first method step illustrated in FIG. 1, a substrate 100 is provided, which consists, for example, of glass and on which two optoelectronic components 200, 300 in the form of organic light-emitting diodes are arranged. In this case, an outer optoelectronic component 200 has a rectangular shape with a central cutout, in which an inner optoelectronic component 300 is arranged, which is completely surrounded by the outer optoelectronic component 200 in a lateral direction and which likewise has a rectangular shape. The centers of the two optoelectronic components 200, 300 coincide here. An intermediate region 400 between the two optoelectronic components 200, 300 is transparent and free of a layer sequence suitable for generating radiation.FIGS. 2 and 3 show schematic sectional views of the structure shown in FIG. 1, the section in FIG. 2 being taken along the line A-A and the section in FIG. 3 being taken along the line B-B in FIG. 1.As illustrated in FIGS. 2 and 3, the outer optoelectronic component 200 comprises an anode 211, which is transparent and consists of indium tin oxide in the present exemplary embodiment, a cathode 212, which is transparent and consists of a thin silver layer in the present exemplary embodiment, and an organic functional layer 213 arranged therebetween. The outer optoelectronic component 200 has outer contact structures 221, 222 made of metal at its edge, which are electrically conductively connected to the anode 211 and the cathode 212, respectively.Analogously, the inner optoelectronic component 300 comprises an anode 311, which is embodied in a transparent manner and consists of indium tin oxide in the present exemplary embodiment, a cathode 312, which is embodied in a transparent manner and consists of a thin silver layer in the present exemplary embodiment, and an organic functional layer 313 arranged therebetween. The inner optoelectronic component 300 has inner contact structures 321, 322 made of metal at its edge, which are electrically conductively connected to the anode 311 and the cathode 312, respectively.FIGS. 2 and 3 furthermore show resistor elements 10 which isolate electrically nonconnected layers from one another. A continuous thin-film encapsulation layer 12 extends over the layer sequences of the two optoelectronic components 200, 300 and over the intermediate region 400, protecting the layer sequence of the two optoelectronic components 200, 300 from moisture and atmospheric oxygen.In the method steps illustrated in FIGS. 4 and 5, the thin-film encapsulation layer 12 is removed in regions 331, 332 of the inner contact structures 321, 322 using laser ablation and the inner contact structures 321, 322 are thereby exposed at least in regions. FIG. 6 shows the exposed regions 331, 332 in a plan view of the optoelectronic components 200, 300.In a further method step, a cover element 500 having a cover carrier 510 and a first and a second contact element 521, 522 formed in a strip shape is provided (FIG. 7 ). The two contact elements 521, 522 are formed by laser structuring of a layer of a transparent conductive oxide, in particular indium tin oxide, on one of the main surfaces of the cover carrier 510. More specifically, the layer is separated by a laser along a straight line 523 such that the contact elements 521, 522 are electrically separated from each other.As shown in FIG. 8, an (electrically non-conductive) adhesive 16 is subsequently applied over a large area to the two contact elements 521, 522 (for example by screen printing), with the exception of two regions 531, 532 in which contacting of the inner contact structures is intended to take place. A conductive adhesive 14 is applied in these regions. Alternatively, the conductive adhesive can also be applied in the exposed regions 331, 332 on the inner contact structures 321, 322.In a further method step illustrated in FIG. 9, the cover element 500 is bonded, for example laminated, onto the glass substrate 100 with the optoelectronic components 200, 300 arranged thereon under the action of the adhesive 16, such that the contact elements 521, 522 in the two regions 331, 332 in which the inner contact structures 321, 322 are exposed are fastened to the latter via the conductive adhesive 14 and are electrically connected thereto. Subsequently, the structure formed thereby is cured.FIGS. 10 and 11 show the finished radiation-emitting device 600 according to the invention according to the first exemplary embodiment in schematic sectional views corresponding to the sectional planes shown in FIGS. 2 and 3.

Claims

Radiation-emitting device (600), comprising - a substrate (100), - at least one inner optoelectronic component (300) and at least one outer optoelectronic component (200), which at least partially laterally encloses the inner optoelectronic component, wherein each of the optoelectronic components comprises a layer sequence suitable for generating electromagnetic radiation, having at least one first electrode area (211, 311), at least one second electrode area (212, 312) and at least one functional layer (213, 313) between the first electrode area and the second electrode area, wherein the functional layer is suitable for generating electromagnetic radiation in a switched-on operating state, and - a cover element (500), which is arranged on the optoelectronic components (200, 300) and at least one first contact element (521), which is connected to the first electrode area (311) of the inner optoelectronic component, and at least one second contact element (522), which is electrically conductively connected to the second electrode surface (312) of the inner optoelectronic component, wherein each of the contact elements (521, 522) extends in each case as far as an edge of the radiation-emitting device, wherein the contact elements (521, 522) are in each case electrically conductively connected to inner contact structures (321, 322) which are arranged on an edge of the inner optoelectronic component and are electrically conductively connected to the electrode surfaces (311, 312) of the inner optoelectronic component, wherein an electrically non-conductive adhesive (16) is applied to the first contact element (521) and to the second contact element (522), with the exception of two regions (531, 532) in which contact is made with the inner contact structures.The radiation emitting device (600) according to claim 1, wherein the substrate (100) and / or the cover element (500) is formed to be translucent.The radiation emitting device (600) according to any of the preceding claims, wherein the contact elements (521, 522) comprise or consist of a transparent conductive oxide.Radiation-emitting device (600) according to one of the preceding claims, wherein an intermediate region (400) between the inner optoelectronic component (300) and the outer optoelectronic component (200) is formed in a translucent manner.The radiation emitting device (600) according to any of the preceding claims, wherein the contact elements (521, 522) are attached to the contact structures (321, 322) via a conductive adhesive (14).Radiation-emitting device (600) according to one of the preceding claims, wherein the contact elements (521, 522) are connected to the contact structures (321, 322) via recesses (331, 332) in a thin-film encapsulation layer (12) which is arranged at least over the layer sequence of the inner optoelectronic component (300).Radiation-emitting device (600) according to one of the preceding claims, wherein the outer optoelectronic component (200) completely laterally encloses the inner optoelectronic component (300).Radiation emitting device (600) according to one of the preceding claims, wherein the outer optoelectronic component (200) and the inner optoelectronic component (300) are arranged concentrically with respect to one another.Radiation-emitting device (600) according to one of the preceding claims, wherein the contact elements (521, 522) are formed in strip form.Method for producing a radiation-emitting device according to one of the preceding claims, comprising the following method steps: - providing the substrate (100) and at least two optoelectronic components (200, 300) arranged on the substrate, wherein the outer optoelectronic component (200) at least partially laterally encloses at least the one inner optoelectronic component (300); - providing the cover element (500), wherein the cover element comprises a cover carrier (510) and at least the first and the second contact element (521, 522) on a main surface of the cover carrier; and - fastening the cover element (500) to the optoelectronic components (200, 300), wherein the first contact element (521) is electrically conductively connected to the first electrode surface (311) of the inner optoelectronic component and the second contact element (522) is electrically conductively connected to the second electrode surface (312) of the inner optoelectronic component, wherein the contact elements (521, 522) are each electrically conductively connected to the inner contact structures (321, 322), which are arranged at the edge of the inner optoelectronic component and are electrically conductively connected to the electrode surfaces (311, 312) of the inner optoelectronic component, wherein the electrically non-conductive adhesive (16) is applied to the first contact element (521) and to the second contact element (522), with the exception of the two regions (531, 532) in which the contacting of the inner contact structures takes place.Method according to Claim 10, wherein the contact elements (521, 522) are fastened via a conductive adhesive (14) to contact structures (321, 322) which are arranged on an edge of the inner optoelectronic component (300) and are electrically conductively connected to the electrode areas (311, 312) of the inner optoelectronic component.The method of claim 11, wherein the contact structures (321, 322) are exposed using laser ablation.The method of any of claims 10-12, wherein the contact elements (521, 522) are patterned using laser ablation.

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