EP1969653A1

EP1969653A1 - Oleds with increased light yield

Info

Publication number: EP1969653A1
Application number: EP06829325A
Authority: EP
Inventors: Bernd Fiebranz
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2006-01-05
Filing date: 2006-12-06
Publication date: 2008-09-17
Also published as: WO2007076913A1; US20090001883A1; DE102006000993B4; US8125145B2; DE102006000993A1; KR20080087026A; JP2009522737A

Abstract

The invention relates to relates to OLEDs which comprise at least one substrate, a first electrode, at least one organic light-emitting layer and a second electrode, either the substrate and the first electrode, the second electrode or the substrate, the first and the second electrode being transparent. The invention is characterized in that at least one transparent layer is arranged on the substrate and/or the transparent second electrode. Said layer contains transparent, preferably spherical particles which protrude at least partially from the at least one layer. The invention also relates to a method for producing the OLEDs and to their use, especially in lighting devices and displays.

Description

OLED s with increased light output

description

The present invention relates to ^OLEDs (Organic Light-Emitting Devices) with increased light-outcoupling, processes for their preparation and their use.

^OLEDs have taken in recent years, rapid development. They are displacing more and more the currently used liquid crystal displays (LCD ^' s). Compared to ^LCD's have the ^OLEDs several advantages: They are characterized firstly by a simpler structure as well as lower power consumption. In addition, they have a lower viewing angle dependence.

The disadvantage ^'s are their too short lifetimes, specifically for durable applications, such as backlighting of ^LCD' to the currently available OLED s and general room lighting, necessary.

On this issue, however, currently being studied intensively, both through development of new light-emitting materials with higher stability and on the other hand by improving the encapsulation of ^OLEDs. Both lead to an increase in the lifetime of ^OLEDs.

Another approach to increase the service life, is to ^'increase s, for example, by increasing the light output of ^OLEDs, the efficiency of OLED's. In this way it is possible to decrease at a constant light output, the current consumption of the ^OLED's (and thus save energy) or to increase the light output for the same electrical power. It is well known that about 40% of the light generated in the emitter layer is already lost in the inner layer systems, ie only 60% of the generated light can leave the inner layer system at all (so-called "internal decoupling") % of the generated light is lost at the boundary substrate / air due to total reflection, so that only about 20 to a maximum of 30% of the total, generated light emerges from the OLED at all (so-called "external decoupling"). The present invention relates to increasing the external output at the substrate / air interface.

In Fig. 1, the internal and external coupling is shown schematically.

There are different approaches for increasing the external coupling-out efficiency. For example, surface structures can be obtained by means of photolithographic structuring, such as e.g. Micro lens systems and pyramidal structures are applied.

Thus, an array of microlenses on ^OLEDs is described for example in US 2003/0020399 A1 having a planar head structure, to improve the light outcoupling. A disadvantage of the planar microlenses, however, is that they do not lead to an improvement in the output in the vertical.

Also, a roughening of the surface can be performed. Furthermore, the use of a substrate glass with a higher refractive index (n ~ 1, 85) is described in US 2004/0007969 A1. The coating of the substrate surface with a diffuser layer to improve the external Auskoppeleffizienz.

The disadvantage to increase the options described, the lifetime of the ^OLEDs and thus their efficiency by reducing the radiation loss, however, is associated with the structuring Effort, eg in the lithographic structuring, and the associated high cost factor and the lack of efficiency improvement, eg when roughening the surface. Even though possible replication methods represent a relatively inexpensive alternative to the photolithographic structuring, no measures to increase the external coupling-out efficiency are currently being implemented for the existing OLED products.

Yamasaki et al. describe in Applied Physics Letters, Vol. 76, no. 10 (2000) ^OLEDs in which on the substrate a monolayer of silica

Microparticles is arranged to increase the decoupling. The particles have a diameter of 550 nm. A disadvantage of the structure described, however, is that due to the small particle size diffraction occurs. Also, the particles are only on the glass and are therefore optically not coupled to the substrate. Thus, this structure only affects the light scattering. The total reflection of the light at the substrate surface remains largely unaffected.

^OLED's having a polymer layer, are embedded in the microparticles are described in WO 03/061028 A2. The polymer layer containing the microparticles is arranged between the substrate and the anode layer, that is, within the ^OLED. The microparticles have a high refractive index of at least 1.7, so as to couple the light generated in the emitter layer into the glass substrate at a steeper angle. Apart from the fact that the described arrangement relates to the "internal release" may cause the insertion of the particle-containing polymer layer to a higher roughness of the anode surface, the properties of the OLED may adversely affect ^s'.

An illumination system comprising a substrate and an active layer containing an electroluminescent material, wherein said active layer is provided between a first, optically transparent electrode layer and a second electrode layer, wherein a light-scattering layer having a medium having light diffusing properties is provided on a side of the transparent electrode layer facing away from the active layer, characterized in that the properties of the light-scattering layer are such that the non-scattering fraction of a light beam as it passes through the light-scattering layer is in the range between 0.005 and 0.8, is disclosed in EP 0 867 104 B1 disclosed.

Starting from the above mentioned closest prior art, it can be used as object of the present invention are considered, ^OLEDs provide s, on the one hand have an increased external light outcoupling, the other hand, are also distinguished by a simple surface modification that is relatively easily manufactured can be. Simple production in this context means both cost-effective production and technically simple production.

The subject of the present invention is thus an OLED ₁ which at least

a substrate,

a 1st electrode,

at least one organic light-emitting layer, and a second electrode, wherein at least either

the substrate and the first electrode,

- the 2nd electrode or

- The substrate, the first and the second electrode are transparent, which is characterized in that on the transparent substrate and / or the transparent second electrode at least one transparent layer, preferably a transparent layer and particularly preferably a transparent film is arranged, which contains transparent, preferably spherical, particles which at least partially protrude from the at least one layer.

On the transparent substrate and on the transparent second electrode means in the present application on the respective outer side, i. the opposite side of the light-emitting layer, the transparent substrate and the transparent second electrode.

In a first preferred embodiment ("bottom emission" OLED), the OLED has the following structure:

a transparent substrate,

a transparent 1st electrode,

at least one organic light-emitting layer, and a second electrode, which is characterized in that on the transparent substrate at least one transparent layer, preferably a transparent layer and particularly preferably a transparent film, is arranged, the transparent, preferably spherical Contains particles which at least partially protrude from the at least one layer.

In a second preferred embodiment ("top emission" OLED), the OLED has the following structure:

a substrate, a first electrode,

at least one organic light-emitting layer, and

a transparent second electrode, which is characterized in that on the transparent second electrode at least one transparent layer, preferably a transparent layer and particularly preferably a transparent film, is arranged, which contains transparent, preferably spherical, particles which are at least partially stand out of the at least one layer. The substrate may be transparent, semi-transparent and non-transparent in this embodiment.

In a third preferred embodiment ("transparent" OLED), the OLED has the following structure:

a transparent substrate,

a transparent 1st electrode,

at least one organic light-emitting layer, and

a transparent second electrode, which is characterized in that on the transparent substrate and / or the transparent second electrode at least one transparent layer, preferably a transparent layer and particularly preferably a transparent film, is arranged, the transparent, preferably spherical, Contains particles that at least partially protrude from the at least one layer. Particularly preferred is in this

Embodiment both on the transparent substrate and on the transparent second electrode in each case at least one transparent layer, preferably in each case a transparent layer and particularly preferably in each case a transparent film, arranged, the transparent, preferably spherical, particles containing at least partially from the respective stand out at least one layer.

In the above embodiments, either the first electrode may be formed as an anode and the second electrode as a cathode, or vice versa, the first alternative being the preferred embodiment.

In the above-mentioned embodiments, an encapsulation is additionally preferably additionally arranged on the second electrode, specifically on the side opposite the light-emitting layer. In the first preferred embodiment (bottom emission OLED), the encapsulation may be transparent, semi-transparent and non-transparent. In the second and third preferred embodiments, the encapsulation is transparent or semitransparent, preferably transparent. With regard to the second and third preferred embodiment, it is particularly preferred if the at least one, preferably one, layer of the encapsulation simultaneously forms the transparent layer containing the transparent, preferably spherical, particles which at least partially protrude from the one layer.

The at least one transparent layer according to the invention must essentially meet a requirement. It must have the necessary transparency. Thus, the choice of available materials is very large. Accordingly, as materials for the at least one transparent layer, all known and commercially available materials, such as e.g. Glass, glassy materials (eg sol-gel systems) and plastics (eg polymer systems) are used, provided they have the appropriate transparency. Preference is given to plastics. The plastics include in particular paints and adhesives.

As lacquers, it is possible to use all lacquers which are suitable for the use according to the invention and which are suitable for the use according to the invention, such as, for example, lacquers which contain the organic binder dissolved in organic solvents and / or water and also powder lacquers. Paints can be labeled according to different criteria. A corresponding overview can be found in the Römpp Chemie Lexikon, volume: Lacke and

Printing Inks, 1998. Preference is given to thermally and UV-curing lacquers. Further preferred are clearcoats.

As adhesives, it is also possible to use all adhesives suitable for the use according to the invention, such as, for example, physically and / or chemically setting adhesives. An overview of physically and chemically setting adhesives can be found in Römpp Chemie Lexikon, Volume 3, 9th edition, 1990. Preference is given to thermally and UV-curing adhesives.

The above-mentioned materials for the at least one transparent layer can be used optimally for the particular type of application (for example spin coating, screen and flexographic printing).

The at least one transparent layer preferably has a layer thickness of 1 μm to 1000 μm. Layer thicknesses in the range from 2 μm to 200 μm are particularly preferred.

As materials for the transparent, preferably spherical particles, it is possible to use all known and commercially available particles, provided that they have the appropriate shape, size and transparency. Preferred materials for the transparent particles are glass, plastic and inorganic oxide particles. Thus, for example, glass or plastic particles which are used as spacers (so-called "spacers") in LCD production can be used, Particular preference is given to silica particles, such as the particles described, for example, in the exemplary embodiments.

The at least one transparent layer, which contains the transparent, preferably spherical particles, can be either full-surface or structured.

Furthermore, the material for the at least one layer and / or the transparent, preferably spherical particles may also be colored. The provision of materials for coloring the at least one transparent layer and the transparent particles is known to the person skilled in the art. In this way it is possible to obtain a colored coupling-out layer. By structuring, it is also possible to provide certain areas of the OLED with a colored decoupling layer. Also, several, different color ranges can be displayed on an OLED, for example by repeated application of differently colored decoupling layers. This makes it possible to combine the increase in light extraction with a colored representation on the OLED.

Transparent in the sense of the present invention means that the material has a light transmittance of> 60 to 100% at least in partial areas, but preferably in the entire area of visible light, semi-transparent means that the light transmittance is in the range of 20 to 60% and non-transparent means that the light transmittance is in the range of 0 to <20%.

The term "at least partially" with respect to the protrusion of the transparent particles from the one layer means in the present invention that at least 10%, preferably 50% and more preferably 90% of the particles partially protrude from the at least one layer.

The transparent particles arranged in the at least one transparent layer are preferably spherical, ie essentially spherical. The transparent, preferably spherical, particles preferably have an average diameter of 1 to 100 .mu.m, particularly preferred are average diameters of 2 to 10 microns. Also mixtures of particles of different size distribution are possible. The refractive index n of the preferably spherical particles varies from 1.3 to 2.0, depending on the nature of the particles. Spherical, ie essentially spherical, in the present invention means that the largest diameter of a particle is at most twice as large as the average diameter and the smallest diameter is at least half as large is like the mean diameter. The surface roughness of the particles is in no way limited, it can range from very smooth to very rough.

Preferably, the transparent particles are from 25 to 75% of their

Diameter, more preferably 40 to 60% of its diameter, and more preferably about 50% of its diameter, out of the at least one transparent layer, i. In particular, they are incorporated approximately halfway into the at least one transparent layer, preferably into the one transparent layer and particularly preferably into the one transparent film.

It has surprisingly been found that it is possible by the inventive arrangement which includes at least one transparent layer, the transparent, preferably spherical particles, which at least partially protrude from the at least one layer of significantly increasing the external extraction of the ^OLEDs.

By the targeted selection of the size of the particles, the surface roughness of the particles and the refractive indices of the particles and the at least one transparent layer, it is also possible, the desired properties such. B. spectral properties to influence.

As substrates, all materials suitable for this purpose can be used. However, preferred substrate materials are glass and plastics, glass being particularly preferred. As glass all kinds of glass can be used, such as typical window glass. Preferably, however, flat glasses are used, as they are used in the display industry (eg soda-lime glass or alkali-free glass). As plastics, all thermoplastics can be used, but preferred are polymers such as polycarbonate (PC), Polymethylmethacrylate (PMMA), polyvinylcarbazole (PVK), polybutadienes, polyethylene (PE), polyethylene terephthalate (PET) and polyesters. For "top emission" ^OLEDs and metallic substrates, such. As metallic foils can be used. The thickness of the substrate is not limited, but is preferably in the range of 0.05 mm to 3, more preferably in Range from 0.2 to 1, 1 mm.

As materials for the preferably, transparent anode are preferably indium tin oxide (ITO, indium tin oxides) or other metal oxides, such as. As indium-zinc oxide (IZO) or aluminum-zinc oxide

(AIZnO), but also doped versions of said oxides (for example, fluorine-doped ITO) used. In addition, a semi-transparent, thin metal layer as an anode or in the case of the "top emission" OLED also a non-transparent anode is conceivable.

The organic light-emitting layer can comprise as light-emitting materials either so-called "small molecules" or polymers.As materials, all materials known and suitable for this purpose by a person skilled in the art can also be used when using a plurality of light-emitting materials, these are arranged in one or more organic light-emitting layers (so-called "multi-layers").

In addition, the ^OLEDs' have further functional layers which can vary according to application can. For example, hole conductor, electron conductor, injection and / or barrier layers are conceivable. These may preferably be present, but are not mandatory.

As materials for the non-transparent or semi-transparent cathode are preferably metallic materials, such as. As Al ₁ Ag, Au or Cr used. In a particularly preferred embodiment, two-way Layer systems (bi-layer) of a thin layer of Ba, Li, LiF, Ca or Mg and a layer of a metal vapor-deposited. As materials for transparent or semi-transparent cathode, for example, for "top emission" ^OLEDs or transparent ^OLEDs, are preferably transparent or semi-transparent cathode materials such as ITO, is used.

As encapsulation, all materials suitable for this purpose can be used. However, preferred encapsulating materials are glass and plastics, with glass being particularly preferred. As glass all kinds of glass can be used, such as typical window glass. Preferably, however, flat glasses are used, as they are used in the display industry (eg soda-lime glass or alkali-free glass). Particular preference is given to using so-called vapor-deposition glasses, as disclosed, for example, in WO 03/088370 A1. As plastics, all thermoplastics can be used, but preferred are polymers such as polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinylcarbazole (PVK), polybutadienes, polyethylene (PE) ₁ polyethylene terephthalate (PET) and polyester. However, it is also possible to use metallic foils as encapsulation. The encapsulation may consist of a single encapsulation layer in the simplest case, but it is also possible to build the encapsulation of several layers. The total thickness of the encapsulation is not limited, but it is preferably in the range of 1 .mu.m to 3 mm, more preferably in the range of 5 .mu.m to 1, 1 mm.

In order to increase the light outcoupling, a modification of the substrate surface and / or the surface of the second electrode or the encapsulation is necessary in the external coupling-out efficiency (substrate-air boundary) in order to reduce the total reflection at the boundary layer. For this purpose, in the present invention, a film in which transparent, preferably spherical particles are incorporated, applied to the substrate and / or the surface of the second electrode or the encapsulation.

In addition to the transparent, preferably spherical particles, non-transparent and / or reflective, preferably spherical particles may also be proportionately embedded in the at least one layer. However, the proportion of non-transparent and / or reflective, preferably spherical particles should not exceed 50%, preferably 25% and particularly preferably 10%. In addition, in addition to the transparent, preferably spherical particles also partially transparent and non-spherical particles such. However, the proportion of transparent, non-spherical particles should not exceed 50%, preferably 25% and particularly preferably 10%.

It is also possible for at least some of the transparent, preferably spherical particles to be aggregated. The aggregation of the particles makes it possible to form a more diffuse surface. As a result, the external light extraction is additionally increased.

The present invention also provides a process for the preparation of an ^OLED, which is characterized in that one of the substrate and / or the second electrode and the encapsulation of the ^OLED at least one, preferably a transparent layer, especially preferably applies a transparent film in which preferably spherical particles are embedded, which at least partially protrude from the at least one layer.

In this case, the preferably a transparent layer containing the transparent, preferably spherical particles, as a film either before the OLED production or thereafter on the substrate and / or the second electrode or the encapsulation used for OLED production. It is possible to apply the film in a first step and then apply the transparent, preferably spherical particles or the film and the transparent, preferably spherical particles together in one step. In two further embodiments, it is possible to introduce either the preferably spherical particles directly into a film or to coat a film with a transparent layer and preferably spherical particles, the film then being laminated to the OLED. Furthermore, it is also possible to treat the substrate and / or the second electrode or the encapsulation directly with the preferably spherical particles during its production.

If a thin-layer encapsulation is used in a "top emission" OLED or a transparent OLED, this encapsulation can simultaneously serve as a carrier layer for the preferably spherical particles, but preferably a transparent protective layer is applied to the thin-layer encapsulation, which mechanically stabilizes the thin-layer encapsulation The transparent protective layer can also serve as a carrier layer for the preferably spherical particles and both properties are combined in one layer system, but it is also possible for the at least one transparent layer, which contains the transparent, preferably spherical particles, additionally on the to arrange transparent protective layer.

The inventive ^OLED's can be for all the skilled person known processes. Such processes include spin, slit, spray and roller coating processes, as well as printing processes such as screen, offset and web printing. In this case, either in a first step, the at least one layer can be applied and then the transparent, preferably spherical particles or the at least one layer and the transparent, preferably spherical particles are applied together in one step. If the preferably spherical particles are applied only after the thin-film coating, dry or wet spray methods can be used. An embedding of the transparent, preferably spherical particles by means of ultrasound is also possible. Further methods for introducing the transparent, preferably spherical particles are known to the person skilled in the art.

If the at least one transparent layer is applied by printing (such as screen, offset and web printing), it may be applied directly to the substrate and / or the second electrode in a structured manner. However, it is also conceivable, by using a UV-curing system, which is applied over the entire surface of the substrate and / or the second electrode (for example by means of spin coating), this by

Maskenbelichtung hardened structured and wash off the non-crosslinked areas (typical lithography process). In this way, structuring of the coupling-out layer is possible. Thus, e.g. certain surfaces, structures and / or characters are applied to the OLED, which then in the on state by the higher

Lichtauskopplung appear brighter than the at least one remaining, darker luminous surface, which have no increased Lichtauskopplung. However, certain areas, structures and / or characters may also be omitted as well, which then appear darker than the at least one remaining luminous area. The structuring can be obtained by first applying the at least one transparent layer and then incorporating the transparent, preferably spherical particles into the at least one layer, the particles being applied at the points at which the at least one at least a layer is located, can be easily removed later. But it is also possible, the particles together with the at least one layer structured in a process step to apply.

After application, the curing of the at least one layer, which contains the transparent, preferably spherical particles, preferably takes place. Curing can be carried out according to all methods known and suitable to the person skilled in the art. However, UV curing and thermal curing are preferred.

A preferred manufacturing method is described below:

After applying a thin layer of polymer or adhesive, the particles are sprayed onto the layer in a dry spray process. The particles not embedded in the layer can then be removed by rinsing with water or by blowing off with compressed air.

Another object of the present invention relates to the use of ^OLEDs according to the invention in lighting devices. The term lighting devices includes, for example, general lighting and backlighting of LCD ^' s.

Another object of the present invention relates to the use of ^OLEDs in display according to the invention.

The invention will be described in more detail below with reference to embodiments, without, however, being limited thereby. Examples

Structure of an OLED

On a glass substrate (thickness: 0.7 mm) with a refractive index of n [589 nm] -1.5, an approximately 130 nm thick ITO layer is sputtered on as anode (n = 1, 8). An approximately 50 nm thick PEDOT (poly (3,4-ethylenedioxythiophene)) layer (Baytron P AL4083) is placed thereon as a hole injection layer. An approximately 80 nm thick emitter layer ("Super Yellow", Merck OLED Materials GmbH) is applied to this layer by spin coating.As a cathode, a thin barium layer and then a thicker (approximately 100 nm) aluminum layer are vapor-deposited in vacuo. Finally, the OLED is encapsulated by sticking a glass plate over its entire area in order to minimize the effects of oxygen and humidity on the OLED.

Fig. 2 shows the typical schematic structure of such ^OLEDs.

Example 1: In order to improve the light output from the OLED substrate, glass spacer spheres (diameter about 5 μm), which are used as spacers for the construction of liquid crystal displays (LCD ^'s ), are introduced into a transparent plastic adhesive film. The balls are thereby introduced into the adhesive layer of the plastic adhesive film that they protrude about half of the approximately 20 microns thick adhesive layer. This film is laminated to the OLED with the beads projecting upwards by means of an immersion oil (n = 1, 52). The oil prevents from forming an air layer between the glass substrate of the ^OLED and the film, which then may cause a total reflection of the light within the substrate again. Thus, it is guaranteed that all

Light beams can be coupled into the plastic adhesive film. In this way direct coating of the ^OLED is made possible by a simple method.

Figure 3 shows a scanning electron micrograph of the adhesive film of Example 1 with the introduced balls. It can clearly be seen how the balls introduced into the adhesive film are approximately half out of the film.

The angle-dependent, relative light intensity is measured by the OLED produced, once without and once with the layer according to the invention which contains transparent, spherical particles which at least partially protrude from the at least one layer.

In FIG. 4, the improvement of the external out-coupling from the measurement of the angle-dependent, the relative light intensity of a reference OLED ^'s (without the inventive layer) and an ^OLED' s, which is coated with the inventive film of Example 1 (coupled with immersion Oil).

The angle of 0 ° corresponds to the normal (vertical) to the OLED substrate. In this vertical observation, a 20% increase in the light intensity is obtained compared with the OLED without the coating according to the invention. This effect is even stronger and increases to over 40%, with a measuring angle in the range of 60 to 80 °.

The spacer beads used in this example have a very narrow diameter distribution and are therefore relatively expensive. Therefore, in the following example SiO ₂ spheres are used with a much wider distribution, but they are much cheaper. Example 2:

There are SiO ₂ balls (d ~ 4 to 7 // m) with a larger diameter distribution, which are manufactured and sold under the name Ronasphere ^® LDP by Merck KGaA, used. These particles are used, for example, as a filler for the cosmetics industry (eg for

Creams) produced on a large scale and are therefore relatively inexpensive. The refractive index of these spheres is about 1, 6. These balls are introduced analogously to Example 1, in the adhesive layer of an adhesive film and measured as described in Example 1 on the OLED.

Figure 5 shows a scanning electron micrograph of the adhesive film of Example 2 with the introduced balls.

In FIG. 6, the improvement of the external out-coupling from the measurement of the angle-dependent, the relative light intensity of a reference OLED ^'s (without the inventive layer) and an ^OLED' s, which is coated with the inventive film of Example 2 (coupled with immersion Oil).

It is, as shown in Figure 6, a significant increase in the light output of about 30 to 40% found.

Example 3: A transparent polymer layer (LCD topcoat) is applied by spin-coating to a glass pane, which constitutes the OLED support. This material is manufactured by Japan Synthetic Rubber (JSR), Japan, and serves as a planarizing layer in LCD color filter production. The solution is prepared by mixing two components (JSR JSS-273A and Optmer JSS-273B) in a weight ratio of 6: 1 (273A: 273B) before use and applying it to the glass plate at 800 rpm. On the still wetted with solvent film in the dried state is about 2 to 3 microns thick, the SiO ₂ balls of Example 2 are distributed by means of a dry spray on the wet film. Thereafter, a 10 minute annealing step at about 120 ⁰ C followed on the hot plate to evaporate the solvent and to polymerize the top coat material. The balls are stored in the film and fixed. Ideally, the spheres dip to half the diameter in the polymer film.

Figure 7 shows a scanning electron micrograph of the adhesive film of Example 3 with the introduced balls.

In FIG. 8, the improvement of the external out-coupling from the measurement of the angle-dependent, the relative light intensity of a reference OLED ^'s (without the inventive layer) and an ^OLED' s, which is coated with the inventive film of Example 3 (coupled with immersion Oil).

As can be seen from the scanning electron micrograph in FIG. 7, part of the transparent, spherical particles is aggregated. As shown in FIG. 8, this aggregation leads to a further improvement of the external light extraction compared to the non-aggregated particles of Examples 1 and 2.

Example 4:

The Ronasphere particles described in Example 2, in an amount of 40 to 50% by weight, based on the paint, are introduced into a screen-printing lacquer MZ paint 093 from Pröll and homogeneously distributed in the paint. This mixture is by means of a screen printing unit patterned on the substrate outside of the ^OLED's printed. The layer, the one

Total thickness (transparent layer and particles) of about 8 to 10 microns, is cured in an oven at about 60 ° C. By the appropriate Concentration of particles in the paint system is achieved a distribution in which the transparent particles protrude from the paint layer. Since the structured part of the layer increases the light output of the ^OLED, this coated region in the on state appears brighter than the rest of the uncoated area, while also light, but not so bright.

9 shows a correspondingly produced OLED with a structured coupling-out layer in the switched-on state.

By coloring the paint and / or the particles, it is also possible to design the structured areas also colored.

In addition, in this case, the lettering can be recognized even in the non-switched-state by the diffuse appearance, which gives the component an additional positive property. In this way it is possible, for. For example, visualizations can be visualized in bright surroundings, which can still be recognized in the dark by the OLED in the switched-on state.

Claims

claims

An OLED comprising at least one substrate, a first electrode, at least one organic light-emitting layer and a second electrode, wherein at least one of the substrate and the first electrode, the second electrode or the substrate, the first electrode. and the second electrode are transparent, characterized in that on the transparent substrate and / or the transparent second electrode at least one transparent layer is arranged, which contains transparent particles which at least partially protrude from the at least one layer.

2. OLED according to claim 1, which has at least one transparent substrate, a transparent first electrode, at least one organic light-emitting layer and a second electrode, characterized in that on the transparent substrate at least one transparent layer is arranged, the transparent Contains particles that at least partially protrude from the at least one layer.

3. OLED according to claim 1, which has at least one substrate, a first electrode, at least one organic light-emitting layer and a transparent second electrode, characterized in that on the transparent second electrode at least one transparent layer is arranged, the transparent

Contains particles that at least partially protrude from the at least one layer.

4. OLED according to claim 1, which has at least one transparent substrate, a transparent first electrode, at least one organic light-emitting layer and a transparent second electrode, characterized in that on the transparent substrate and / or the transparent second electrode at least one transparent layer is arranged, which contains transparent particles which at least partially protrude from the at least one layer.

5. OLED according to one or more of claims 1 to 4, characterized in that a transparent layer is arranged on the substrate and / or the second electrode.

6. OLED according to one or more of claims 1 to 5, characterized in that a transparent film is arranged on the substrate and / or the second electrode.

7. OLED according to one or more of claims 1 to 6, characterized in that the first electrode is formed as an anode and the second electrode as a cathode.

8. OLED according to one or more of claims 1 to 7, characterized in that on the opposite side of the light-emitting layer of the second electrode also has a

Encapsulation is arranged.

9. OLED according to one or more of claims 1 to 8, characterized in that the particles are spherical.

10. OLED according to one or more of claims 1 to 9, characterized in that the transparent particles have an average diameter of 1 to 100 microns.

11. OLED according to one or more of claims 1 to 10, characterized in that the transparent particles protrude with 25 to 75% of their diameter from the at least one layer.

12. OLED according to one or more of claims 1 to 11, characterized in that the substrate consists of glass.

13. OLED according to one or more of claims 1 to 12, characterized in that the at least one layer and / or the transparent particles are colored.

14. OLED according to one or more of claims 1 to 13, characterized in that the at least one layer is structured.

15. A method for the production of OLED ^'s according to one or more of claims 1 to 14, characterized in that the substrate and / or the second electrode of ^OLED' s applying a transparent film in which transparent, preferably spherical particles at least partially stored.

16. Use of ^OLEDs according to one or more of claims 1 to 14 in lighting devices.

17. Use of ^OLEDs according to one or more of claims 1 to 14 in displays.