Patent Application
20160343971
This disclosure relates to a light-emitting device and a method of producing a light-emitting device.
It could be helpful to provide a light-emitting device that is damaged to the least possible extent in the event of mechanical loading and a method of producing a light-emitting device in which the device is damaged to the least possible extent during the production process.
We provide a light-emitting device including a substrate having a substrate upper side, a layer sequence arranged on the substrate upper side and having at least one active, light-emitting, organic layer, wherein the layer sequence includes a plurality of emission regions that emit light, current-conducting rails which are a part of the layer sequence, wherein, in a plan view of the substrate upper side, the emission regions of the layer sequence are arranged next to the current-conducting rails, an encapsulation glass, wherein the layer sequence is arranged between the substrate and the encapsulation glass, and spacers formed as elevations on an encapsulation glass underside and facing towards the layer sequence of the encapsulation glass, wherein, in a plan view of the substrate upper side, the spacers at least partly overlap with the current-conducting rails, and the spacers prevent direct contact between the encapsulation glass and the layer sequence in the emission regions.
We also provide a light-emitting device including a substrate having a substrate upper side, a layer sequence arranged on the substrate upper side and having at least one active, light-emitting, organic layer, wherein the layer sequence includes a plurality of emission regions that emit light, current-conducting rails which are a part of the layer sequence, wherein, in a plan view of the substrate upper side, the emission regions of the layer sequence are arranged next to the current-conducting rails, and the current-conducting rails intersect at intersection points, an encapsulation glass, wherein the layer sequence is arranged between the substrate and the encapsulation glass, spacers formed as elevations on an encapsulation glass underside and facing towards the layer sequence of the encapsulation glass, wherein the spacers are formed as buffer points, wherein the buffer points are mutually spaced-apart, dome-shaped elevations arranged in a matrix in a regular pattern on the encapsulation glass underside, in a plan view of the substrate upper side, each spacer at least partly overlaps with an intersection point of the current-conducting rails, and the spacers prevent direct contact between the encapsulation glass and the layer sequence in the emission regions.
We further provide a method of producing the light-emitting device including a substrate having a substrate upper side, a layer sequence arranged on the substrate upper side and having at least one active, light-emitting, organic layer, wherein the layer sequence includes a plurality of emission regions that emit light, current-conducting rails which are a part of the layer sequence, wherein, in a plan view of the substrate upper side, the emission regions of the layer sequence are arranged next to the current-conducting rails, an encapsulation glass, wherein the layer sequence is arranged between the substrate and the encapsulation glass, and spacers formed as elevations on an encapsulation glass underside and facing towards the layer sequence of the encapsulation glass, wherein, in a plan view of the substrate upper side, the spacers at least partly overlap with the current-conducting rails, and the spacers prevent direct contact between the encapsulation glass and the layer sequence in the emission regions, including providing a substrate having a substrate upper side, applying a layer sequence to the substrate upper side, wherein an edge region of the substrate upper side is provided at least partly to be free from the layer sequence, providing an encapsulation glass having an encapsulation glass underside, applying an adhesive layer to the encapsulation glass underside, applying spacers to the encapsulation glass underside so that the spacers are bordered by the adhesive layer, and joining the substrate and the encapsulation glass together so that the substrate upper side and the encapsulation glass underside face towards one another and the adhesive layer is arranged in the edge region of the substrate upper side.
Our light-emitting device may comprise a substrate having a substrate upper side. The substrate preferably comprises a radiation-transmissive, in particular transparent or milky-cloudy material, e.g., glass or synthetic materials. Preferably, the substrate consists of such a material. In particular, the substrate can be provided for use in coupling-out light from the light-emitting device. The substrate upper side is, e.g., a major side of the substrate.
The light-emitting device may comprise a layer sequence arranged on the substrate upper side. The layer sequence can comprise, e.g., at least one active, light-emitting, organic layer. The layer sequence further comprises one or a plurality of emission regions that emit light. The emission regions can be understood to be the regions which in a plan view of the device appear to be light-emitting. In particular, the entire active organic layer can be light-emitting, but only from some regions does the light actually travel to the observer. These regions are then, e.g., the emission regions. The different emission regions are preferably operated in parallel or simultaneously. In other words, the different emission regions are preferably driven together, e.g., via a single switch, rather than separately.
The layer sequence has, e.g., a lateral extent in parallel with the substrate upper side of ≧2 cm or ≧5 cm or ≧10 cm. Alternatively or in addition, the lateral extent of the layer sequence is ≦35 cm, e.g., ≦30 cm or ≦20 cm. The emission regions have, e.g., a lateral extent of at least 100 μm or 1 mm or 2 mm. Alternatively or in addition, the lateral extent of the emission regions is ≦5 mm, or ≦4 mm or ≦3 mm.
In addition to the active organic layer, the layer sequence can also comprise further organic layers such as, e.g., electron injection layers or hole injection layers. Furthermore, it is possible for the layer sequence to comprise a plurality of active organic layers all emitting electromagnetic radiation, and comprise, e.g., different emitters emitting in different wavelength ranges. The thicknesses of the individual organic layers is, e.g., at least 10 nm or ≧100 nm or ≧200 nm. Alternatively or in addition, the thicknesses of the individual organic layers are ≦500 nm or ≦200 nm or ≦100 nm.
The light-emitting device may comprise current-conducting rails. The current-conducting rails are a part of the layer sequence. If the light-emitting device is viewed in a plan view of the substrate upper side, the emission regions of the layer sequence are preferably arranged next to or between the current-conducting rails. In a plan view of the substrate upper side, the current-conducting rails can form, e.g., a grid, e.g., a rectangular or hexagonal grid. The current-conducting rails then include rectangular or hexagonal regions of the layer sequence. These regions can be emission regions. In particular, it is possible that no light travels to the observer from the regions of the active organic layer which in a plan view overlap with the current-conducting rails, e.g., because the active organic layer in these regions does not emit any light or because the current-conducting rails act in a light-absorbing manner.
The current-conducting rails preferably comprise a metallic material such as gold or silver or aluminum or platinum, or consist at least of one of such a material. In particular, it is possible for the current-conducting rails to comprise a layer sequence of a plurality of metallic materials, e.g., a chromium-aluminum-chromium layer sequence. However, a molybdenum-aluminum layer sequence is also possible. The current-conducting rails further comprise, e.g., a width of ≧60 μm or ≧70 μm or ≧80 μm. Alternatively or in addition, the width of the current-conducting rails is ≦150 μm or ≦90 μm or ≦95 μm. The thickness of the current-conducting rails is, e.g., at least 3 μm or ≧3.5 μm or ≧4 μm. Alternatively or in addition, the thickness of the current-conducting rails is ≦6 μm or ≦5.5 μm or ≦5 μm. The width or the thickness of the current-conducting rails can be understood to be the average or the maximum or minimum width or thickness.
The light-emitting device may comprise an encapsulation glass. The layer sequence is enclosed between the encapsulation glass and the substrate. In a plan view of the substrate upper side, the encapsulation glass thus partly or completely covers the layer sequence. The encapsulation glass can comprise a light-transmissive, e.g., milky-cloudy or transparent material, e.g., a silicate glass or a synthetic material, or can consist of such a material. Preferably, the encapsulation glass is formed as a platelet comprising two plane-parallel major sides. The major sides then extend, e.g., in parallel to the substrate upper side.
The light-emitting device may comprise spacers. The spacers are formed as elevations on an encapsulation glass underside, e.g., a major side facing towards the layer sequence of the encapsulation glass. In a plan view of the substrate upper side, the spacers preferably partly or completely overlap with the current-conducting rails. In particular, the spacers prevent direct contact between the encapsulation glass and the layer sequence, specifically in the emission regions of the layer sequence.
The spacers can be, e.g., a structuring of the encapsulation glass. However, in particular, the spacers can also be applied directly to the encapsulation glass and can consist of a different material than the material of the encapsulation glass.
The light-emitting device may comprise a substrate having a substrate upper side. Arranged on the substrate upper side is a layer sequence comprising at least one active, light-emitting, organic layer. Moreover, the layer sequence comprises one or a plurality of emission regions that emit light. The layer sequence further comprises current-conducting rails, wherein in a plan view of the substrate upper side the emission regions of the layer sequence are arranged between or next to the current-conducting rails. Furthermore, the light-emitting device comprises an encapsulation glass, wherein the layer sequence is arranged between the substrate and the encapsulation glass. Spacers are applied to the encapsulation glass, wherein the spacers are formed as elevations on an encapsulation glass underside facing towards the layer sequence. In a plan view of the substrate upper side, the spacers at least partly overlap with the current-conducting rails of the layer sequence. The spacers prevent direct contact between the encapsulation glass and the layer sequence in the region of the emission regions.
The layer sequence is preferably not in direct contact with the encapsulation glass. Instead, it is possible that a cavity is formed between the layer sequence and the encapsulation glass in the region of the emission regions, the cavity being filled, e.g., with a gas. Therefore, during production of the light-emitting device foreign particles enclosed between the layer sequence and the encapsulation glass are not pressed into the layer sequence or are pressed therein to a lesser extent. This reduces damage to the light-emitting device during the production process. After the production process, the light-emitting device is also less susceptible to damage. By virtue of the fact that the spacers are preferably provided above or opposite the current-conducting rails, in the event of a mechanical loading on the light-emitting device, the spacers are preferably pressed only onto the regions of the layer sequence in which current-conducting rails are provided. Although in these regions the layer sequence, in particular the active organic layer, can then be adversely affected, these regions are preferably not provided to emit light. Instead, the light-emitting emission regions advantageously lie next to the current-conducting rails. Therefore, in the event of a mechanical loading, the emission regions are not brought into contact with the spacers and are thus also not damaged.
The spacers may be formed as buffer points. The buffer points are mutually spaced-apart dome-like elevations on the encapsulation glass underside.
The buffer points on the encapsulation glass underside have, e.g., a lateral extent along the encapsulation glass underside of at least 50 μm or 100 μm or 150 μm. Alternatively or in addition, the lateral extent of the buffer points is ≦300 μm or ≦250 μm or ≦200 μm. The thickness of the buffer points perpendicular to the encapsulation glass underside is preferably at least 10 μm or 20 μm or 30 μm. Alternatively or in addition, the thickness of the buffer points is ≦50 μm or ≦40 μm or ≦30 μm. The lateral extent of the buffer points is preferably at the most 5% or at the most 2% or at the most 1% or at the most 0.1% of the lateral extent of the encapsulation glass.
The current-conducting rails may intersect at intersection points. At such an intersection point, at least two or three or four or five current-conducting rails intersect. The spacing between two adjacent intersection points of the current-conducting rails is, e.g., at least 1 mm or 2 mm or 3 mm. Alternatively or in addition, the spacing between two adjacent intersection points is ≦5 mm or ≦4 mm or ≦3 mm.
In a plan view of the substrate, upper side the buffer points are arranged on the encapsulation glass underside preferably such that they at least partly or completely overlap with the intersection points of the current-conducting rails. Preferably, each buffer point at least partly or completely overlaps with only one intersection point.
Such a structure is particularly advantageous if the light-emitting device is mechanically loaded. If, e.g., pressure is exerted upon the encapsulation glass or upon the substrate, the spacers in the form of buffer points press preferably only onto regions of the layer sequence in which the current-conducting rails intersect. On the one hand, these intersection points can form mechanically particularly stable regions of the device, on the other hand these regions are generally not provided to emit electromagnetic radiation. Damage to the active organic layer in the region of the intersection points thus preferably continues to have no effect upon the optical properties of the light-emitting device.
The current-conducting rails may be arranged between the active organic layer and the substrate. The current-conducting rails can lie on the substrate upper side, wherein further layers or materials can certainly be located between the current-conducting rails and the substrate. The active organic layer is placed, e.g., onto the current-conducting rails and can conform to the structure of the current-conducting rails. In other words, as seen from the substrate upper side the active organic layer can be located at a higher position in the region of the current-conducting rails than in the regions between the current-conducting rails, e.g., in the emission regions. Alternatively, it is also possible for the current-conducting rails to be countersunk in the substrate so that the current-conducting rails and the substrate terminate flush with one another at the substrate upper side. In this case, the active organic layer can be characterized, e.g., by two major sides extending in a planar manner and in parallel with the substrate upper side.
The layer sequence may comprise a first electrode, e.g., an anode. The first electrode is arranged, e.g., between the current-conducting rails and the substrate. The first electrode can comprise the same material as or a different material from the current-conducting rails. In particular, the first electrode comprises a transparent conductive material, e.g., a transparent oxide material, TCO for short such as, e.g., indium tin oxide, ITO for short.
The layer sequence may comprise a second electrode, e.g., a cathode. The second electrode can be arranged, e.g., downstream of the active organic layer in a direction away from the substrate upper side. In this case, the active organic layer lies between the second electrode and the substrate. The second electrode can comprise, e.g., a metal such as gold or silver or aluminum, or can consist of such a material. In particular, the cathode can comprise a material which is reflective to the light emitted by the active organic layer.
In the two examples above, the light-emitting device is preferably formed as a bottom emitter. In other words, the light from the active organic layer is coupled out of the light-emitting device via the transparent conductive anode and via the substrate which in this case is transparent.
However, it is also possible for the cathode to comprise a conductive transparent material and for the anode to comprise a reflective material. It is further possible for the light-emitting device to be formed as a top emitter, wherein, e.g., an electrode arranged between the active organic layer and the substrate is formed to be reflective and accordingly an electrode arranged downstream of the active organic layer in a direction away from the substrate upper side can be transparent to the light emitted by the active organic layer. In this case, the light from the active organic layer is coupled out from the light-emitting device, e.g., via the encapsulation glass.
The thicknesses of the anode and the cathode are, e.g., at least 50 nm or 100 nm or 200 nm. Alternatively or in addition, the thicknesses of the anode and the cathode are ≦500 nm or ≦300 nm or ≦250 nm.
The buffer points may be arranged matrix-like on the encapsulation glass underside of the encapsulation glass. Such an arrangement proves to be particularly advantageous if the current-conducting rails form a regular grid. To ensure that in a plan view of the substrate upper side the buffer points overlap, e.g., with the intersection points of the current-conducting rails, the buffer points can likewise comprise a regular, in particular matrix-like, arrangement. For example, hexagonal or rectangular matrix patterns are possible.
The spacers on the encapsulation glass may be at least temporarily not in direct contact with the layer sequence. In particular, the light-emitting device can be designed such that a direct contact between the spacers and the layer sequence only occurs when the light-emitting device is loaded mechanically, e.g., under pressure on the encapsulation glass or on the substrate. Furthermore, the light-emitting device can, however, also be designed such that at least in some regions the spacers are permanently in direct contact with the layer sequence even without any mechanical loading on the device.
The substrate upper side may comprise an edge region at least partly free from the layer sequence. The edge region of the substrate upper side can be, e.g., a region which adjoins lateral surfaces of the substrate, wherein the lateral surfaces extend transversely with respect to the substrate upper side and define the substrate in the direction in parallel with the substrate upper side. Preferably, an adhesive layer is applied to the edge region of the substrate upper side. The adhesive layer preferably covers regions of the edge region free from the layer sequence. Furthermore, the adhesive layer contacts, in particular in direct contact, the encapsulation glass underside of the encapsulation glass, and thereby establishes a mechanical connection between the substrate and the encapsulation glass. In a plan view of the substrate upper side, the adhesive layer forms, e.g., a continuous, contiguous path around the layer sequence. The layer sequence is thus defined by the adhesive layer, e.g., in all directions in parallel with the substrate upper side, but does not necessarily have to be in direct contact with the adhesive layer. In particular, the adhesive layer can connect the encapsulation glass and the substrate together such that an air-tight intermediate space is produced between the encapsulation glass and the substrate. For example, the layer sequence is then arranged in the intermediate space.
The adhesive layer comprises, e.g., a resin, in particular the adhesive layer can be a UV-curing adhesive. Moreover, the adhesive layer preferably comprises a thickness perpendicular to the substrate upper side of at least 10 μm or 30 μm or 50 μm. Alternatively or in addition, the thickness of the adhesive layer is ≦80 μm, e.g., ≦70 μm or ≦60 μm. The lateral extent of the adhesive layer in parallel with the substrate upper side, in particular the width of the path from the adhesive layer which extends around the layer sequence is, e.g., at least 1 mm or 5 mm or 1 cm. Alternatively or in addition, the lateral extent of the adhesive layer is ≦2 cm, e.g., ≦1.5 cm or ≦1.2 cm.
An absorption material may be introduced between the layer sequence and the encapsulation glass. The absorption material can be used to capture and absorb water molecules and/or oxygen molecules that could damage the layer sequence, in particular the organic active layer. To this end, the absorption material can comprise an oxidizable material such as, e.g., an alkali metal or an alkaline earth metal. For example, the absorption material can comprise magnesium, calcium, barium, cesium, cobalt, yttrium, lanthanum and/or rare earth metals. In particular, metal oxide compounds such as calcium oxide, barium oxide or magnesium oxide can also be used as the absorption material. The absorption material is preferably a liquid absorption material which is introduced, e.g., in droplet form between the layer sequence and the encapsulation glass. By using such a liquid absorption material, it is possible to prevent the absorption material from being pressed into the layer sequence in the event of a mechanical loading on the light-emitting device.
The adhesive layer and the spacers may be produced from the same material. In particular, the material of the adhesive layer and the spacers differs from the material of the encapsulation glass. By using the same material for the adhesive layer and the spacers, the adhesive layer and the spacers can, for example, be applied to the encapsulation glass in a common step during the production process.
The layer sequence may comprise a thin-film encapsulation. The thin-film encapsulation partly or completely covers all of the sides of the layer sequence not covered by the substrate upper side of the substrate. In particular, the sides of the layer sequence are completely covered with the thin-film encapsulation to such an extent that only the regions of the layer sequence which for contacting purposes must be free remain uncovered by the thin-film encapsulation. As a result, the thin-film encapsulation acts as additional protection for the layer sequence, in particular the active organic layer, against reactions and/or oxidation processes with the surrounding area.
The thin-film encapsulation is, e.g., a layer of silicon oxide or silicon nitride or aluminum nitride deposited onto the layers of the layer sequence preferably by chemical vapor deposition, CVD for short, or physical vapor deposition, PVD for short, or sputtering. In particular, the thin-film encapsulation comprises a layer thickness of at the most 50 nm or 100 nm or 200 nm. Alternatively or in addition, the thickness of the thin-film encapsulation is ≦1000 nm or ≦400 nm or ≦300 nm.
The current-conducting rails may at least be partly covered with an insulating material. In particular, at least 80% or 90% or 95% of the side of each current-conducting rail facing away from the substrate is covered with the insulating material. Furthermore, it is also possible for lateral surfaces of the current-conducting rails extending transversely with respect to the substrate upper side to be at least partly coated with the insulating material. If the spacers are pressed onto the layer sequence, e.g., by reason of a mechanical pressure on the light-emitting device, the metallic cathode could thus be pressed through the active organic layer onto the current-conducting rails. Without the insulating material on the current-conducting rails, the light-emitting device could possibly short-circuit and fail.
The current-conducting rails may be embedded in the substrate so that the current-conducting rails terminate, e.g., flush with the substrate on the substrate upper side. Preferably, the insulating material is then arranged in the form of rails between the active organic layer and the second electrode so that in a plan view of the substrate upper side the current-conducting rails at least partly overlap with the insulating material.
We also provide a method of producing a light-emitting device. The light-emitting device described here can be produced by the method described herein. That is to say that all of the features disclosed in conjunction with the production method are also disclosed for the light-emitting device, and vice versa.
A substrate having a substrate upper side may be provided. In a subsequent step, a layer sequence is applied to the substrate upper side. An edge region of the substrate upper side is to remain at least partly free from the layer sequence. Therefore, no layer sequence is applied in this region or the layer sequence is then removed in a subsequent step.
The application of the layer sequence can include a plurality of intermediate steps. For example, a transparent conductive anode, a grid of current-conducting rails, one or a plurality of active organic layers, a reflective cathode and a thin-film encapsulation are applied consecutively to the substrate upper side.
An encapsulation glass having an encapsulation glass underside may be provided. An adhesive layer can be applied to the encapsulation glass underside. Furthermore, spacers can be applied to the encapsulation glass underside. Subsequently, e.g., the substrate and the encapsulation glass are then joined together, wherein the substrate upper side and the encapsulation glass underside face towards one another. The joining procedure is effected preferably such that the adhesive layer is arranged in the edge region of the substrate upper side.
The spacers are advantageously applied such that after the substrate and the encapsulation glass have been joined together, spacers partly cover the current-conducting rails of the layer sequence in a plan view of the substrate upper side.
The spacers and the adhesive layer may be applied to the encapsulation glass underside in a common screen printing process or ink-jet process or pad printing process. Preferably, the spacers and the adhesive layer comprise the same material. However, it is also possible for the spacers to be introduced directly into the encapsulation glass, e.g., by structuring the encapsulation glass.
A light-emitting device and method described herein to produce a light-emitting device will be explained in greater detail hereinafter with the aid of examples. Like reference numerals designate like elements in the individual figures. However, none of the references are illustrated to scale; rather individual elements can be illustrated excessively large for improved understanding.
Current-conducting rails 210 are arranged downstream of the anode 21 in a direction away from the substrate upper side 11. The current-conducting rails 210 each have a main extension direction TS which in
A layer of an insulating material 25 is arranged downstream of the current-conducting rails 210 in a direction away from the substrate upper side 11. The insulating material 25 covers, e.g., at least 99% of the side of the current-conducting rails 210 facing away from the substrate 11. However, in addition the insulating material 25 can also cover, e.g., at least 95% of lateral surfaces of the current-conducting rails 210 extending transversely with respect to the substrate upper side 11. The insulating material 25 prevents a possible short-circuit between the anode 21 and a further electrode in the event of a mechanical loading on the light-emitting device 100. The insulating material 25 is, e.g., a layer of a photoresist or an epoxy resin. The average or maximum or minimum thickness of the layer of the insulating material 25 is, e.g., 1 μm to 6 μm.
An active organic layer 20 is arranged downstream of the transparent anode 21 and the current-conducting rails 210 in a direction away from the substrate upper side 11. The active organic layer 20 is placed over the current-conducting rails 210 such that the active organic layer 20, as seen from the substrate upper side 11, is located at a higher position in regions of the current-conducting rails 210 than in the regions between the current-conducting rails 210. In
In
Furthermore, the layer sequence 2 in
The layer sequence 2 in
According to the example in
In
The encapsulation glass 3 is formed as a platelet comprising two plane-parallel major sides. The major sides extend in parallel with the substrate upper side 11. In
The spacers 4 can be formed in particular as buffer points 41, wherein a buffer point 41 is a dome-like elevation from the encapsulation glass underside 31.
In
In
In
In
In the example in accordance with
The side views of examples of the device 100 as illustrated in
After applying the adhesive layer 6 and the spacers 4 to the encapsulation glass 3, the encapsulation glass 3 and the substrate 1 connect together as shown in
Our methods and devices described herein are not limited by the description made with reference to the examples. Rather, the disclosure encompasses any new feature and any combination of features, including in particular any combination of features in the appended claims, even if the feature or combination is not itself explicitly indicated in the claims or examples.
This application claims priority of DE 10 2014 100 770.0, the subject matter of which is incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 100 770.0 | Jan 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/050984 | 1/20/2015 | WO | 00 |
