DE102006039789A1 - Flat luminous element and use of the planar luminous element - Google Patents

Abstract

The invention relates to a planar luminous element, wherein the luminous element is constructed from at least one organic light emitting diode, wherein a plurality of points of the anode (3) are at least approximately at the same potential, wherein the organic light emitting diode consists of a cathode (1) and an anode (3) and at least one organic layer (2) between the cathode (1) and the anode (3), wherein at least one of the at least one organic layers (2) upon application of an electrical voltage to the cathode (1) and the anode (2) light wherein no material of the cathode (1) and the organic layer (2) is present for electrical contacting of the plurality of points (7) of the anode (3) at these points (7), so that the corresponding points (7) of the anode (3) are contactable from the back of the flat luminous element. Moreover, the invention relates to the use of such a lighting element for the illumination of street signs and / or signals.

Description

The The present invention relates to a planar luminous element after The preamble of claim 1 and the use of such a planar luminous element according to claim 3.

Of the Applicant are approaches known, organic light emitting diodes (OLEDs) in the field of lighting and signaling / signage. Such lighting elements are made up of at least one organic light emitting diode, with several Points of the anode at least approximately lie at the same potential, the organic light emitting diode from a conductive Cathode and anode and at least one organic layer between the cathode and the anode, of which at least one layer when a voltage is applied to the cathode and the anode emits light.

One particular advantage results from the fact that the light-emitting diode is thin, be executed over a large area may need only a low voltage and potentially also flexible can be configured.

The However, electrodes of an OLED have due to the materials used and / or the low layer thicknesses a relatively high resistance. This especially applies to that often for the Anode used material Indium Tin Oxide (ITO). Especially at high current densities arises due to this resistance to large emissive Areas Voltage drop, which leads to significant inhomogeneities in the luminance. specially in lighting applications requiring large and homogeneous illuminated areas, this is problematic.

This could for example solved become new, higher more conductive Materials with similar Properties like the previous anodes. Such materials are currently not known. There are currently additional conductive Auxiliary structures (e.g., metal strips) or layers on the anode applied to the conductivity to increase and thus the homogeneity the current and consequently the luminance to improve.

Of the The present invention is based on the object, the homogeneity of the luminance to improve such lighting elements.

These The object is achieved according to the present invention according to claim 1, by for electrically contacting the points of the anode to a plurality Points no material of the cathode and the organic layer present is so that the corresponding points of the anode from the back of the flat Lighting element from contactable are.

Advantageous can be avoided by this embodiment that metallic Connections are mounted on the visible side of the luminous element, to apply a voltage to the corresponding points. Especially there is also the possibility to the middle of the area to provide such points without partially covering this area.

The Production of such flat Lighting elements can be done by means of shadow masks or by means of a material removal of the cathode and the at least one organic Interlayer in a subsequent manufacturing step. Generally let yourself this production under the term "suitable structuring measures" summarize. these can for example, in lithographic steps, printing or consist of other manufacturing processes.

When particularly advantageous over In the prior art it turns out that the production step can be omitted for applying the metallic contact tracks. This Step had to be done consistently in a vacuum and brought problems with impurities and related functional problems.

at The embodiment according to claim 2, the cathode and the at least organic layer produced in a first step over the entire surface, wherein subsequently at the appropriate points a removal of the material of Cathode and the material of at least one organic layer takes place.

These Removal of the layers may, for example, by means of a microstructuring, a laser radiation, by mechanical means or even chemically respectively.

These Procedure proves to be particularly easy in the production feasible.

claim 3 relates to the use of a flat luminous element according to Claim 1 or 2 for the Illumination of street signs and / or signals.

in this connection proves the uniform illumination also larger areas comparatively low energy consumption as particularly advantageous.

The electrical contact can be done by means of spring contacts. The holes at the corresponding points in the cathode and the at least one organic layer can comparatively be made small, so that they are no longer noticeable at a relatively short distance from the light emitting element.

at According to the present invention, the anode is different from the prior art The technique does not overlap laterally powered by wide metallizations, but by many punctual contact points over the entire area are distributed. This will be explained in the following drawing.

The Contact points can be, for example, according to the following procedure produce. The OLED consists for example of the layer sequence glass substrate / ITO anode / organic Layers / metal cathode. Other anode materials and layer sequences as well as substrate materials are also possible. By means of a fine Laser beam of suitable wavelength or by microstructuring become the organic layers and removed the cathode of the OLED. The bare anode remains, at this point (from the non-emitting back the OLED) freely accessible and isolated from the cathode. By suitable contact (e.g., by spring contact pins) may be energized at such location be fed into the anode.

simultaneously the cathode remains from the back accessible. Many such contact points can supply power to the OLED become. The density and position of the contacts on the needed Current density and their required homogeneity matched. You can do that made small be that they are already short on the front of the OLED Distance are no longer perceptible.

To The present invention may be advantageous additional Metal structures or layers omitted on or under the Anode be attached to increase the conductivity. Thereby deleted advantageous a complex Process step, which usually has to take place in a vacuum. Any metal structure on / under the anode reduces the emitting surface of the OLED. This is considerably less in the present invention Dimensions of the case, because the contacts have a punctual character and do not represent lines.

Also finds no interference in the area of the electrically active layers when processing the MONEY instead, which, for example, the burden reduced by particles / residues and thus the reliability, performance and visual appearance the OLED positively influenced.

The For example, ablation of the OLED layers down to the anode with an established laser process quickly and automatically and with it economical respectively.

The The density and position of the contact points can be varied as needed become.

There by the present invention, the lateral feed tracks attributable to the anode on the substrate, the filling factor is increased on the substrate. at same size can a larger proportion of area be used to generate light.

at a structure of several LEDs, the individual tiles packed with less or no gap closer together become. Thus, for example, the homogeneity of a huge Area, which consists of individual elements, significantly improved.

One embodiment the invention is shown in the drawing. The two figures show:

1 a section of a flat luminous element in a lateral section and

2 : the planar luminous element in plan view.

1 shows a flat luminous element in a lateral section. It is the substrate 4 to be seen as a carrier of the flat luminous element.

Attached to it is the anode 3 , which may for example consist of indium tin oxide (ITO). Between this anode 3 and the metallic cathode 1 is an organic layer 2 brought in.

It can also be seen that in the cathode 1 as well as in the organic layer 2 Holes are introduced. In the 1 you can see that through these holes contact pins 6 are plugged, by means of which the anode 3 connected to a voltage source. It can also be seen that the cathode 1 also connected to the voltage source.

The anode 3 is thus contacted by the back of the flat luminous element ago.

With the reference number 5 the light is indicated, which is emitted by the flat luminous element.

Unless the cathode 1 consists of individual surface elements, a contact with the voltage source must be present for each of these surface elements. Unless the cathode 1 is formed as a continuous surface with the holes, it may be sufficient to produce a contact of the cathode with the voltage source in a metal cathode.

2 shows a part of the planar luminous element in plan view. It's the holes 7 to see through the contacting of the anode takes place. Likewise, the emitting surface 8th to see.

Claims (3)

Flat luminous element, wherein the luminous element is constructed from at least one organic light emitting diode, wherein a plurality of points of the anode ( 3 ) are at least approximately at the same potential, wherein the organic light emitting diode from a cathode ( 1 ) and an anode ( 3 ) and at least one organic layer ( 2 ) between the cathode ( 1 ) and the anode ( 3 ), wherein at least one of the at least one organic layers ( 2 ) upon application of a voltage to the cathode ( 1 ) and the anode ( 3 ) Emits light, characterized in that for the electrical contacting of the multiple points ( 7 ) of the anode ( 3 ) at these points ( 7 ) no material of the cathode ( 1 ) and the at least one organic layer ( 2 ), so that the corresponding points ( 7 ) of the anode ( 3 ) are contactable from the back of the flat luminous element. Luminous element according to claim 1, characterized in that the cathode ( 1 ) and the at least one organic layer ( 2 ) are produced over the entire surface in a first step, and then at the corresponding points ( 7 ) a removal of the material of the cathode ( 1 ) as well as the material of the at least one organic layer ( 2 ) he follows. Use of a flat luminous element according to Claim 1 or 2 for the lighting of street signs and / or signals.