EP2067190A2

EP2067190A2 - Radiation-emitting device

Info

Publication number: EP2067190A2
Application number: EP07817510A
Authority: EP
Inventors: Markus Klein; Florian Schindler; Ian Stephen Millard; Sok Gek Beh
Original assignee: Osram Opto Semiconductors GmbH
Current assignee: Osram Oled GmbH
Priority date: 2006-09-29
Filing date: 2007-09-11
Publication date: 2009-06-10
Also published as: WO2008040288A3; CN101553941A; DE102006055884A1; TWI354389B; CN101553941B; KR101424305B1; WO2008040288A2; DE102006055884B4; US20120176027A1; JP2010505248A; JP5424882B2; US20100007269A1; US8159129B2; TW200816539A; US8749134B2; KR20090057460A

Abstract

The invention relates to a radiation-emitting device comprising a substrate (100) and a series of layers arranged thereon. Said series of layers comprises a first electrode surface (200) having a first contact pad (210) for the application of a voltage, at least one functional layer (300) which emits radiation during the operation of the device, and a second electrode surface (400). The series of layers also comprises a plurality of sections (330) which are modified such that the emission of radiation visible to an outside observer is interrupted from said sections. The distribution density of the sections varies according to the distance of same from the contact pad.

Description

description

Radiation-emitting device

The invention relates to a radiation emitting

Device with at least one functional layer which emits radiation during operation.

This patent application claims the priority of German patent applications 10 2006 055 884.7 and 10 2006 046 234.3, the disclosure of which is hereby incorporated by reference.

Radiation-emitting devices are suitable as large-area, thin light-emitting elements. However, due to their construction, they have a voltage drop along the lateral direction, which affects the luminance and thus the brightness. The emitted light is thus not homogeneous, but has differences in the local luminance.

The object of the invention is to provide a radiation-emitting device, which is characterized by an improved, homogenized luminance and thus reduces the above-mentioned disadvantages.

This object is achieved by a radiation-emitting device according to claim 1. Particularly advantageous embodiments and further radiation-emitting devices are the subject of further claims. In radiation-emitting devices according to an embodiment of the invention, a multiplicity of partial regions are introduced into the layer sequence in which the luminance of the radiation is reduced.

Such a radiation-emitting device preferably comprises a substrate and a layer sequence arranged on the substrate. The layer sequence comprises a first electrode surface on the substrate with a first contact for applying a voltage, at least one functional layer which emits radiation during operation, and a second electrode surface on the at least one functional layer. In this layer sequence, a plurality of sub-areas is present, which is modified so that out of them the emission of visible to an external observer radiation is interrupted. The distribution density of these subregions varies depending on their distance from the contact. The advantage here is that the luminance of the radiation-emitting device varies as a function of the distance from the contacting.

Due to the large number of partial regions whose distribution density depends on the distance to the contacting, the changed luminance can be counteracted. In this case, the modified partial regions are particularly advantageously arranged in the regions of the radiation-emitting device in which, without these partial regions, normally a higher luminance would be present. In this way, the luminance can be reduced in these areas and thus a more uniform distribution of the luminance over the entire luminous area

(Radiation exit surface) of the radiation-emitting device can be achieved. This leads to a Homogenization of the luminance of the illuminated parts.

A further advantageous feature of a further embodiment of the invention is a radiation-emitting device with partial regions which are not recognizable to the naked eye by an external viewer. Furthermore, the radiation-emitting device can also have partial areas that have microscopic dimensions. As a result, the luminous impression is not disturbed by the external observer, but he perceives only the luminance changed or homogenized by the introduced subregions.

Furthermore, the invention may have the advantageous feature that the radiation-emitting device has partial regions which reduce the luminance of the emitted radiation. This has the advantage that areas of the functional layer, which would have a high luminance without the partial areas, can be regulated by introducing the partial areas in their average brightness.

Advantageously, the first contact is present on the side of the first electrode surface. Thus, the first electrode surface can be supplied with voltage.

Advantageously, a third contact is provided laterally of the second electrode surface, whereby the second electrode surface can be supplied with voltage.

The at least one functional layer may conveniently comprise an organic functional layer and preferably also comprise a charge transport layer. The material of Functional layer may include polymers and / or Sraall Molecules. Thus, the radiation-emitting device is an organic, light-emitting diode (OLED), which is particularly well suited as a large-area light-emitting element.

The at least one functional layer can also be an inorganic functional layer, for example based on phosphide or nitride compound semiconductors. Preferably, the materials are those having the general formula Al _n Ga _m In _n- _ra P, where O ≦ _n ≦ l, O ≦ _m ≦ l and n + m <1 or nitride III / V compound semiconductors, preferably general formula Al _n Ga _m In; i _. - _n - _m N, where O ≤ n ≤ l, 0 ≤ m ≤ 1 and n + m <1.

The voltage drop of the radiation-emitting device may be due, inter alia, to the conductivity of one or both of the first and second electrode surfaces. The first and / or second electrode surface may be a semi-transparent or a transparent electrode surface, which include radiation-emitting functional layers. In this case, one of the two electrode surfaces may also be a reflective electrode surface. The conductivity of the transparent electrode surfaces can be limited by two to three or more orders of magnitude compared to the conductivity of a reflective electrode

Be electrode surface. In the case of electrode surfaces of this kind, a voltage drop can occur which increases with increasing distance from the contacts of the first and / or second transparent electrode surfaces and thus can lead to a weakening of the luminance. The emitted light is therefore not homogeneous, but has differences in luminance. Furthermore, the radiation-emitting device can preferably have a first and / or second electrode surface, which is semitransparent or transparent for the radiation emitted by the functional layer. The advantage here is that the generated radiation can be emitted through the first and / or second electrode surface. Opposite electrode surfaces, which consist of pure, thick metal layers and are not transparent, electrode surfaces, which have metals and / or other components and are transparent, have a lower conductivity. The voltage applied to the contacts voltage decreases with increasing distance from the contact and thus leads to a decreasing luminance of the radiation-emitting device.

The material of the first and / or second electrode surface comprises metal oxides in a favorable embodiment. Transparent conductive oxides ("TCO" for short) are transparent, conductive materials, usually metal oxides, such as zinc oxide, tin oxide,

Cadmium oxide, titanium oxide, indium oxide or indium tin oxide (ITO). In addition to binary metal oxygen compounds such as ZnO, SnO ₂ or In ₂ O _{3 also} include ternary metal oxygen compounds such as Zn ₂ SnO ₄ , CdSnO ₃ , ZnSnO ₃ , MgIn ₂ O ₄ , GaInO ₃ , Zn ₂ In ₂ O ₅ or In ₄ Sn ₃ Oi ₂ or

Mixtures of different transparent conductive oxides to the group of TCOs. Furthermore, the TCOs do not necessarily correspond to a stoichiometric composition and may also be p- or n-doped.

Likewise, transparent electrodes may include highly conductive organic materials such as PEDOT, or doped organic layers include metals, such as Ag, or combinations of the above options.

Another advantageous feature of another embodiment of the invention is a

Radiation-emitting device having between the first and the second electrode surface a plurality of insulating and / or non-transparent to the radiation elements in the sub-areas. Their distribution density and / or geometric shape in turn varies depending on the distance of the elements from the first and / or third contact. These elements have the advantage that they can modify the distance from the contacting dependent brightness of the radiation-emitting device. Thus, in this embodiment, the abovementioned partial regions are modified by the insulating and / or non-transparent elements for the radiation in such a way that the coupling out of the radiation from the device is blocked out of them.

Advantageously, the distribution density of the insulating and / or non-transparent elements decreases with increasing distance from the first and / or third contacting. Furthermore, the insulating and / or non-transparent elements present between the first and second electrode surfaces can prevent emission of radiation from the device in these subregions. This has the advantage that the regions of the layer sequence that would have a high luminance without the elements and that are close to the first and / or third contact, a high distribution density of insulating and / or non-transparent elements and the regions which, without the elements, would have a reduced luminance compared to the regions closer to the contacting and which are located farther away from the contacting, have a low distribution density of insulating and / or non-transparent elements. The radiation emission is thus reduced more by the elements in the areas of normally high luminance than in areas of normally low luminance. Thus, the luminance difference across the area is reduced or compensated with a suitable variation of the distribution density.

It is particularly advantageous if the distribution density of the insulating and / or non-transparent elements is chosen so that the difference in the luminance of the radiation emitted by the device between different areas of the device with different distribution densities of the elements is not more than 20%. The advantage of this is that such a

Brightness difference is barely perceptible by an external observer and conveys an improved, more homogeneous luminance.

The insulating and / or non-transparent elements can furthermore be formed in a line shape and arranged in a periodic structure in the functional layer. Such a periodic structure may include, for example, a grid. The grid may have a grid spacing between adjacent line-shaped elements, which increases with increasing distance from the first and / or third contact. Such a grid with varying periodicity can be easily and inexpensively in the Install radiation-emitting device without significantly changing the layer sequence of the device. Also, the manufacturing process does not have to be changed over to install such a grid in the device.

At least between the line-shaped elements, the functional layer can be arranged. The layer thickness of the functional layer between adjacent line-shaped elements can continue to decrease with increasing lattice spacing of the elements. The functional layer can also be arranged in addition over the linear elements. Thus, with the grid spacing, the layer thickness of the functional layer between adjacent line-shaped elements can be controlled, since when the at least one organic functional layer is applied, uncontrolled material transport across the electrode surface is prevented or prevented by the linear insulating and / or non-transparent elements arranged in a grid. is reduced. This may be due to the surface tension of the material of the functional layer between adjacent line-shaped elements.

The material transport can be further prevented by the fact that the insulating and / or non-transparent elements are not or only slightly wetting for the material of the organic functional layer. In the areas delimited by the line-shaped insulating and / or non-transparent elements, the material of the functional layer accumulates independently of one another during the application of the material for the functional layer by means of a wet-chemical method, such as spin coating or doctoring, for example, and dries depending on the grid spacing to a specific one layer thickness. The layer thickness of the functional layer can decrease with increasing lattice spacing of the insulating and / or non-transparent elements, which is due to the surface tension of the solution of the material for the functional layer. In the areas bounded by adjacent insulating and / or non-transparent elements, the functional layer can thus be formed in a uniform layer thickness. In this case, as the distance of the line-shaped elements from the first and / or third contacting increases, the layer thickness of the organic functional layer between adjacent line-shaped elements decreases, since the distance of the adjacent line-shaped elements increases with greater distance from the first and / or third contacting.

Furthermore, the intensity of the emitted radiation can decrease with increasing layer thickness. This means that with increasing distance from the contacting, the lattice spacing between adjacent line-shaped elements becomes larger, and thus the layer thickness of the functional layer present between the linear elements becomes smaller. In the areas near the contact, in which without the linear elements a stronger intensity of

Radiation would be present, thus the intensity is reduced both by the greater layer thickness of the functional layer and by the greater number of line-shaped insulating and / or non-transparent elements and uniform over the entire electrode surface for a viewer. By unifying the emitted radiation, a viewer is less sensitive to any other variances of the emitted radiation or defects and therefore has an improved, more uniform overall impression.

Furthermore, the intensity of the emitted radiation can increase with increasing layer thickness. In this case, furthermore, the lattice spacing can increase with increasing distance from the decrease first and / or third contact to obtain the emitted radiation unified across the surface.

In an advantageous embodiment, the insulating elements comprise electrically insulating elements and, due to their electrically non-conductive properties, interrupt the emission of the radiation in the subregions of the layer sequence in which they are present. This breaks the radiation in the subregions and the radiation loses brightness across the surface.

Furthermore, the material of the electrically insulating elements may be transparent to the emitted radiation and the size of the insulating elements may advantageously comprise a few micrometers, preferably less than 200 microns, preferably less than 100 microns, more preferably less than 20 microns. The advantage here is that the insulating elements, and thus the non-luminous regions of the radiation-emitting device, are generally not resolvable with the naked eye and thus do not disturb the overall image of the luminous area. Due to the varying distribution density, only as many insulating elements are present as necessary, so that only a small area coverage of the first and / or second electrode surface is present through the electrically insulating elements.

For this, the material of the electrically insulating elements may advantageously be selected from a group comprising photoresists, nitrides, ceramics, oxides and organic insulating compounds. In a further advantageous embodiment, the elements in the subregions in the layer sequence are not transparent to the emitted radiation but instead reflect and / or absorb it. Thus, the emission or generation of radiation in the layer sequence is not interrupted, but only their coupling out of the radiation-emitting device out blocked. The brightness differences in the device are thus modified. Advantageously, the material of the non-transparent elements comprises metals.

In a further embodiment, the metals of the non-transparent elements are surrounded by an insulating shell, which may be, for example, a polymer shell.

In a further embodiment, the elements which are not transparent to the radiation may be electrically conductive printed conductors. Advantageously, these conductor tracks extend away from the first and / or third contact via the first and / or second contact

Electrode area. Their distribution density decreases favorably with increasing distance from the first and / or third contact. For this purpose, it is advantageous if adjacent conductor tracks have different lengths and the length distribution of the conductor tracks, starting from the first and / or third contacting, has at least one maximum and one minimum. This embodiment has the advantage that due to the varying distribution density as a function of the distance from the first and / or third contact, the emitted radiation is modified in such a way that the

Luminance differences, which are present without the introduced tracks, can be compensated or reduced. Due to the increasing distance from the first and / or third contacting decreasing distribution density of the conductor tracks, the area coverage of the first and / or second electrode surface is kept as low as possible.

Furthermore, the first and / or third contact can be present on all sides of the first and / or second electrode surface. Thus, the first and / or third electrode surface is enclosed on all sides by the contact. Are the tracks in a periodic

Structure arranged, for example, a grid with a grid spacing between adjacent line-shaped elements, the grid spacing increases with increasing distance from the first and / or third contact and may for example be largest in the middle between opposite first and / or second contacts.

Furthermore, it is advantageous if the width of the interconnects is a few millimeters, preferably less than 200 microns, preferably less than 100 microns, more preferably less than 20 microns. This has the advantage that the tracks can not be perceived by an external observer with the naked eye.

Furthermore, the thickness of the conductor tracks can advantageously have a range of less than 200 μm, preferably a range of 100 nm to 10 μm. Thus, they have the advantage that they can be present on the surface of the first and / or second electrode and also extend through the entire functional layer and can pierce it. In this case, the conductor tracks surround an insulating layer, for example an insulating layer Polymer layer. As a result, short circuits with the (second) respectively different electrode layer are avoided.

In a further advantageous embodiment, the first electrode surface may have a second contact for applying a voltage. Advantageously, the second electrode surface may have a fourth contact. Furthermore, further electrically conductive strip conductors may be present, which extend from the second and / or fourth contacting over the first and / or second electrode surface. This embodiment has the advantage that the radiation coupled out by the radiation exit surface has a luminance which has a minimum brightness in the region between the first and second and / or the third and fourth contacts, which can be compensated for by arranging the conductor tracks according to the invention. It is particularly advantageous if the distribution density of the conductor tracks, which extend from the second and / or fourth contact via the electrode surface decreases with increasing distance and if the outgoing from the first and second and / or third and fourth contact tracks are not overlap and so do not exceed the brightness minimum. Furthermore, it is advantageous if adjacent conductor tracks have different lengths and the

Length distribution of the conductor tracks, starting from the first and second and / or third and fourth contacting each have at least a maximum and a minimum. The advantage here is that the interconnects again have a varying, decreasing distribution density, which depends on the distance to the first and second and / or third and fourth contacts. In a further embodiment, the maxima and minima of the length distribution may be opposite to the printed conductors emanating from the first and second and / or third and fourth contacting. Preferably, the maxima and minima of the length distribution of the outgoing from the first and second and / or third and fourth contact strip conductors are arranged offset from each other. The advantage of mutually shifted maxima and minima is that the brightness modification is symmetrized.

Another advantageous feature of a further embodiment of the invention are printed conductors, which have branches. It is advantageous if with increasing distance from the contact increasingly more branches are arranged. The conductor tracks may, for example, run parallel to the lateral current density. Preferably, the thickness and / or width of the conductor tracks decreases with increasing distance from the contact. This embodiment represents a quasi-fractal distribution of the interconnects. The advantage of this embodiment is that less the brightness is blocked, but rather the conductivity of the first and / or second electrode surface is increased by the attachment of the interconnects according to the invention. Thus, the brightness is increased in areas of low luminance due to the increased conductivity of the first and / or second electrode surface by the conductor tracks. At the same time, the coverage of the luminous area by the interconnects is kept as low as possible, since their width decreases with increasing degree of branching and thus cover the non-transparent to the radiation interconnects less and less of the radiation area. A further advantageous feature of a further embodiment is a radiation-emitting device in which the first and / or second electrode surface has structurings of the electrode material in the partial regions of the layer sequence. Advantageously, the distribution density of these structures decreases with increasing distance from the first contact. Such modifications may also include portions of the electrode that are free of electrode material, that is, have holes in the electrode. The advantage of this embodiment is that the luminance is modified by modifying the conductivity of the electrodes.

A further advantageous feature of a further embodiment is a radiation-emitting device in which the at least one functional layer in the partial regions has a conductivity reduced by lack of doping or an increased injection barrier for charge carriers. Advantageously, the distribution density of the subregions decreases with increasing distance from the contacting. The advantage of this embodiment is the modification of the luminance by the lack of doping, which depends on the distance from the contacting.

The invention further relates to a method for

Production of a radiation-emitting device according to the exemplary embodiments listed above. The method steps include arranging a layer sequence on a substrate, wherein a multiplicity of subregions are introduced in the layer sequence. This variety of

Subareas are modified in such a way that the emission of the radiation visible to an external observer is interrupted out of them. The subareas will be like this generates that their distribution density varies depending on their distance from the contact.

Furthermore, between the first and second electrode surfaces a plurality of insulating and / or non-transparent to the radiation elements in the sub-areas can be introduced with a Aufdampfmaske. The advantage here is that the subregions are introduced into the layer sequence in one process step.

Furthermore, in the method, the first and / or second electrode surface in the partial regions can be structured and / or the functional layer in the partial regions can not be doped.

With reference to the figures and the embodiments, the invention will be explained in more detail:

Figure 1 shows the structure of a radiation-emitting device with a plurality of sub-areas in

Cross-section .

FIG. 2 shows an experimental and a simulated distribution of the luminance distribution in conventional large area OLEDs.

Figure 3 shows a brightness-voltage characteristic connected to a diode characteristic of a conventional light-emitting diode.

FIG. 4 shows the current density of a conventional OLED

Area . FIG. 5 shows the luminance in cross section over a conventional OLED.

FIG. 6 shows a plan view of an exemplary embodiment of a first electrode surface with a first contact and with insulating elements.

FIG. 7 shows a plan view of the first electrode surface with a first and a second contact and with insulating elements, as well as the luminance distribution and element density.

Figure 8 shows the structure of another embodiment of the radiation-emitting device according to the invention with a plurality of sub-regions in cross-section.

FIG. 9 shows a plan view of the first electrode surface with a first and a second contacting arranged on the conductor tracks together with the luminance distribution and surface coverage.

FIG. 10 shows a plan view of a further exemplary embodiment of the first electrode surface with applied conductor tracks.

FIG. 11 shows a plan view of a first electrode surface with branched conductor tracks.

FIG. 12 shows a plan view of the first electrode surface with a first contact and with insulating or non-transparent elements which are formed in a line-shaped manner. W

- 18 -

FIG. 13 shows a schematic cross section to FIG. 12, with the layer thickness between the line-shaped elements.

In Figure 1, the general structure of a

Radiation-emitting device according to an embodiment of the invention. On the substrate 100 there is a first electrode surface 200 with a first 210 and a second contact 220. On the substrate, a functional layer 300 is arranged, which has insulating elements 310, which have a decreasing distribution density D with increasing distance from the contact. The direction in which the distribution density D decreases is indicated in FIG. 1 by an arrow. Finally, a second electrode surface 400 is arranged on the functional layer 300. As a result of the introduced insulating elements 310, the layer sequence of first electrode surface 200, functional layer 300 and second electrode surface 400 has a plurality of partial regions 330, which can extend through the entire layer sequence or the second

Protruding electrode surface 400 and interrupt the emitted radiation. A indicates the sectional area on which the supervision takes place in FIG.

FIG. 2 shows an experimental and simulated measurement of the luminance of a conventional OLED. In the diagram E, the side of the electrode surface for contacting x is plotted against the exposed side y. The luminance R is high in the bright areas and low in the dark areas. Since an OLED with two opposite contacts was measured in the experiment, there is a luminance minimum in the middle range between the contacts. A very similar result comes with a Achieved simulation, which is shown in the diagram S. Here, too, the side of the electrode surface for contacting x is plotted against the exposed side y and the luminance R is indicated across the surface. The luminance is also in the range of the largest here

Distance from both contacts (the top and bottom x-axis) lowest. This is because the conductivity of the electrode surface decreases with increasing distance from the contacts and thus also a lower luminance is achieved.

Figure 3 shows the luminance differences in conventional diodes in the form of a brightness-voltage characteristic connected to a diode characteristic. In this case, the voltage V is plotted on the x-axis, the current density C _d on the left y-axis and the luminance R on the right-hand y-axis. At low voltages, both the current density and the luminance are low. Both curves increase steeply with increasing voltage. This means that both the current density and the luminance with increasing

Voltage rise, or decrease with decreasing voltage.

The consequence of this is shown in FIG. Here, the lateral current density Ca in the electrodes is shown by the area of a conventional OLED surface stretched from the side surface for contacting x and the exposed side surface y. At the contacts, ie at the lower and upper x-axis, the voltage is high and thus the current density is high (long arrows). Takes the distance to the

Contacting the center of the surface, the current density also decreases (short arrows). This creates over the OLED surface a luminance inhomogeneity with a minimum luminance.

A further illustration of the luminance inhomogeneity of a conventional OLED is shown in FIG. The diagram represents the luminance distribution along a cross-section of an OLED along the exposed side surface y from the first to the second contact. The luminance R is applied to the left y-axis. It is high at the lateral edges, ie near the contacts towards the middle. This is evidenced by an experiment E (solid line) and a simulation S (points), both of which give well consistent results.

In Figure 6 is an example of an inventive

Embodiment shown. An electrode surface 200 with insulating elements 310 and a first lateral contact 210 is shown in plan view along the exposed surface. Underneath is the substrate 100. The lateral contacting is connected to the second electrode surface 400 via connections 500 and an electrical conductor 510. For the sake of clarity, the functional layer 300 is not shown, the second electrode surface 400 only indicated. The distribution density D of the insulating elements decreases with increasing distance from the contacting. This direction of distribution density D, in which it decreases, is shown by an arrow. Advantageously, these insulating elements are so small that they are no longer resolvable for an external observer. That is why they are smaller than 200 μm, preferably smaller than 20 μm. They are electrically insulating elements and put in the subregions 330 in which they are located in these Ranges without the elements normally present luminance R of the emitted radiation, that is, they prevent the emission of radiation from the radiation-emitting device out in the areas in which they are located. This is done by interrupting the radiation through the insulating elements that block the radiation due to its non-conductive property. Advantageously, the variation of the distribution density of the insulating elements is chosen such that the difference in the luminance at the different distances from the contacting on the surface of the functional layer is less than 20%. The insulating elements are favorably transparent to the emitted radiation and may consist of photoresists, nitrides, ceramics and oxides. Preferably, the insulating elements are electrically insulating elements. Also possible are electrically insulating encased metals.

FIG. 7 shows a variation of the embodiment shown in FIG. The plan view is to be understood along the surface A of FIG. Here, a second contacting 220 is arranged opposite the first contacting 210, wherein both contacts are connected via electrical conductors 500 and electrical connections 510 to the second electrode surface 400. Underneath is the substrate 100. On the electrode surface 200 are again electrically insulating elements 310. The functional layer 300 is not shown for clarity, the second electrode surface only hinted way. Since their distribution density D, as shown by an arrow, decreases with increasing distance from the contacts, their concentration in the middle of the surface is the lowest. This means in areas without the electrically insulating Elements would have a high luminance R, near the contacts, break the insulating elements in many sections 330, the emitted radiation while in areas which would have a lower luminance without the electrically insulating elements, at a greater distance from the contacts, only to a small extent interrupt the emitted radiation because its distribution density is lower. Thus, they compensate or reduce the luminance differences that would normally occur in conventional radiation-emitting devices, which would be present without the insulating elements. At the same time, the decreasing distribution density can cause the smallest possible area coverage of the radiation-emitting device. The relationship between luminance R and element density D in cross section along the exposed side surface y is shown in the diagram next to the drawing. In regions having a high luminance Ri without the insulating elements, the element density D is also high, in low-luminance regions, the element density is low. The resulting luminance R ₂ with the elements is thus approximately independent of the distance from the contacts (upper and lower axis).

Figure 8 shows the general structure of a

Radiation-emitting device according to an embodiment of the invention. On the substrate 100 is a first electrode surface 200 with a first 210 and second contact 220. On the substrate, a functional layer 300 is arranged, the electrically conductive

Conductor tracks 320 which have a decreasing with increasing distance from the contact distribution density D. The direction in which the distribution density decreases is shown with an arrow. Finally, a second electrode surface 400 with a third 410 and fourth contact 420 is arranged on the functional layer 300. Here, too, conductor tracks 320 are present whose distribution density D increases with increasing distance from the

Contacting decreases. As a result of the introduced interconnects 320, the layer sequence comprising first electrode surface 200, functional layer 300 and second electrode surface 400 has a plurality of partial regions 330 which extend through the entire layer sequence and interrupt the emitted radiation. A indicates the sectional area, the top view of which is shown in the following figures. In the following figures, only the first electrode surface 200 is discussed, but the same applies to the second electrode surface 400, in the case that the second electrode surface 400 is also a semi-transparent or transparent electrode surface.

FIG. 9 shows a further embodiment of the device according to the invention. The top view along the surface A from FIG. 8 onto the first electrode surface 200 arranged on the substrate 100 is shown, with a first 210 and second contacting 220, which lies opposite the first one. The two contacts are connected to the second electrode surface 400 via electrical conductors 500 and electrical connections 510. On the electrode surface conductor tracks 320 are arranged. These may also be present on the second electrode surface 400, but the following description relates only to the first electrode surface 200. The conductor paths each extend away from the contacts over the first electrode surface. In this case, adjacent tracks have different lengths and the length distribution of Conductor tracks has maxima and minima starting from the contacts. This results in that the interconnects have a distribution density D, which decreases laterally with increasing distance from the contacts, which is represented by the arrow. The longest or shortest tracks lie exactly opposite each other, but do not touch. Thus, the area with the lowest luminance is free of traces. The result is that there is no area coverage, while in the area near the contacts, where without the electrical traces a high luminance would prevail, there is a larger area coverage. The width of the tracks is favorably less than 200 microns, preferably less than 20 microns, so that the tracks are no longer perceptible to an external observer. The thickness of the

Conductor tracks may be in a range of less than 200 .mu.m, preferably in a range of 100 nm to 10 .mu.m, that is, the conductor tracks may lie only on the surface of the electrode surface, or extend into the functional layer 300 lying on the electrode surface. In a further embodiment, these can also pierce the second electrode surface. In this case, the individual interconnects are surrounded by an insulating layer. In addition to the plan view of the electrode surface, a diagram is again shown in which the relationship between luminance R and surface coverage SC in cross section along the exposed side surface y is shown. The solid lines represent the ideal curves, the dashed ones the real ones. In areas where there is a large luminance R ₁ without the traces, the surface coverage is high, in areas of low luminance R ₁ , the surface area is low. With the inventive arrangement of the tracks results W

- 25 -

a resulting luminance R2, which is approximately independent of location, ie y.

An alternative embodiment to the example shown in FIG. 9 is shown in FIG. Here, the maxima and minima of the length distribution of the interconnects 330 on the electrode surface 200 are not opposite, but shifted from each other. Thus, the distribution density D, which decreases in the direction of the arrow, although in the farthest range of the contacts 210 and 220 is higher than in the

Example of Figure 8, but the luminance distribution is better symmetrized. The relationship between the luminance R ₁ shown in the diagram next to the plan view of the electrode surface, which is present without the conductor tracks, the surface coverage SC and the resulting luminance R ₂ is approximately equal to that shown in FIG. This example of the arrangement of printed conductors can also apply to the first and second electrode surfaces.

Another embodiment of the invention is shown in FIG

11 is shown. Here, the luminance differences on the honeycomb-shaped electrode surface segments are overcome by introducing branched conductive lines 320. Their degree of branching increases with increasing distance from the contacts, while their thickness and / or width a decreases. Thus, even with many branches 340, the area coverage is kept as low as possible, while the conductivity is increased by the tracks in the areas further away from the contacts. The direction of decreasing distribution density D is one

Arrow shown. This example of the arrangement of printed conductors can also apply to the first and second electrode surfaces. FIG. 12 shows, analogously to FIGS. 7 and 9, a variation of an exemplary embodiment. The plan view is to be understood along the surface A of FIG. 1 and FIG. 8. Here is the first contact 210 on all sides of the

Electrode surface 200, wherein it is connected via an electrical conductor 510 and electrical connections 500 to the second electrode surface 400. Underneath is the substrate 100. On the electrode surface 200 are electrically insulating or non-transparent, linear elements 350, which are arranged in the form of a periodic structure, a grid. The grid has a grid spacing 315 between adjacent line-shaped elements, which increases with increasing distance from the contact 210 and is greatest in the middle between the sides of the electrode area where the contact is located. The functional layer 300 is not shown for the sake of clarity, the second electrode surface 400 only hinted.

That is, in regions close to the contact, which would have a high intensity of the emitted radiation without the line-shaped elements, the insulating line-shaped elements 350 in many sub-regions 330 interrupt the electrical contact between them

Electrode surfaces and the functional layers and prevent so that radiation is emitted from these areas, while in areas at a greater distance from the contact, which would have a lower intensity of the emitted radiation without the electrically insulating, linear elements, the small extent interrupt emitted radiation, since the grid spacing 315 is larger there. The width of the electrically insulating, line-shaped elements is less than 200 microns, preferably less than 20 microns, their thickness may be in a range of less than 200 microns, preferably in a range of 100 nm to 10 microns. Thus, they are no longer perceptible to an outside observer.

If the line-shaped elements 350 are non-transparent electrically conductive printed conductors, these can also be present on the second electrode surface 400, but the following description applies only to the first electrode surface 200. Thus, the region with the least intensity of emitted radiation is large Grid spacing covered to each other, while near the contact the grid is denser. The result is that in the area near the contact, where would exist without the electrical traces a high luminance, there is a larger area coverage with traces. The width of the conductor tracks is less than 200 .mu.m, preferably less than 20 microns, so that the tracks are no longer perceptible to an external observer. The

Thickness of the conductor tracks may be in a range of less than 200 .mu.m, preferably in a range of 100 nm to 10 .mu.m, which means that the conductor tracks may lie only on the surface of the electrode surface or extend into the functional layer 300 lying on the electrode surface. In a further embodiment, these can also pierce the second electrode surface. In this case, the individual interconnects are surrounded by an insulating layer, for example a polymer layer.

In addition, the layer thickness of the functional layer 300 present between the line-shaped elements 350 also varies such that the layer thickness increases with increasing Grid spacing 315 decreases. This can be seen in Figure 13, in which a schematic cross section along the axis B indicated in Figure 12 is shown. Here, the substrate 100 with the first electrode surface 200 and the first contact 210 can be seen. This can be the

Enclose electrode surface 200 from all sides, which is not shown in the perspective shown in Figure 13. On the first electrode surface are the linear elements 350, which are arranged in the form of a grid, wherein in FIG

Orientation are drawn. The line-shaped elements have a grid spacing 315 which increases with increasing distance from the contact 210 and has a maximum approximately in the middle of the electrode area. Between the linear elements 350 is the

Functional layer 300, which has a decreasing layer thickness d with increasing lattice spacing. The second electrode surface, the third contact and the electrical connections are not shown in FIG. 13 for reasons of clarity.

With decreasing layer thickness d of the functional layer 300, ie increasing grid spacing 315 of the linear elements 350, the intensity of the emitted radiation can increase. Thus, in areas further from the contact 210, the radiation is additionally increased. This compensates or reduces the luminance differences which normally occur in conventional radiation-emitting devices, which would be present without the linear elements: The linear elements can be non-transparent conductor tracks, conductor tracks with an insulating layer but also include electrically insulating materials, for example a photoresist.

The invention is not limited by the description with reference to the embodiments. Rather, the invention encompasses any novel feature as well as any combination of features, including in particular any combination of features in the claims, even if this feature or combination itself is not explicitly stated in the patent claims or exemplary embodiments.

Claims

claims

A radiation emitting device comprising

a substrate (100), a layer sequence arranged on the substrate, comprising

a first electrode surface (200) on the substrate with a first contact (210) for applying a voltage, at least one functional layer (300) which emits radiation during operation and,

- a second electrode surface (400) on the at least one functional layer, wherein a plurality of subregions (330) is present in the layer sequence, which is modified so that out of them the emission of visible to an external observer radiation is interrupted, the Distribution density of these subregions varies depending on their distance from the contact.

2. Radiation-emitting device according to the preceding claim, wherein the subregions (330) are not visible to an external observer with the naked eye.

3. Radiation-emitting device according to one of the preceding claims, wherein in the sub-areas

(330) the luminance of the emitted radiation is reduced.

4. Radiation-emitting device according to one of the preceding claims, wherein the subregions (330) have microscopic extensions.

5. Radiation-emitting device according to one of the preceding claims, wherein the first contact

(210) is provided laterally on the first electrode surface (200).

6. Radiation-emitting device according to one of the preceding claims, wherein laterally on the second electrode surface (400), a third contact (410) is present.

7. Radiation-emitting device according to one of the preceding claims, wherein the at least one functional layer (300) comprises an organic functional layer.

8. The radiation-emitting device according to claim 1, wherein the at least one functional layer (300) comprises a charge transport layer.

9. The radiation-emitting device according to claim 1, wherein the first and / or second electrode surface (200, 400) is semitransparent or transparent to the radiation emitted by the functional layer (300).

10. A radiation emitting device according to any one of the preceding claims, wherein the material of the first and / or second electrode surfaces (200) is selected from a group comprising transparent metal oxides, organic conductive materials and doped organic materials.

11. Radiation-emitting device according to one of the preceding claims, wherein between the first (200) and second electrode surface (400) a plurality of insulating (310) and / or non-transparent to the radiation elements (320) in the sub-regions (330) is present, whose distribution density and / or geometric shape varies as a function of the distance of the elements from the first contact (210).

12. Radiation-emitting device according to the preceding claim, wherein the insulating (310) and / or non-transparent to the radiation elements

(320) have a distribution density which decreases with increasing distance from the first contact (210).

13. A radiation emitting device according to any one of the preceding claims 11 or 12, wherein the insulating (310) and / or non-transparent to the radiation elements (320) in areas between the first (200) and second electrode surface (400) are present and in these partial areas (330) prevent emission of radiation from the device.

14. A radiation-emitting device according to one of the preceding claims 11 to 13, wherein the distribution density of the insulating (310) and / or non-transparent to the radiation elements (320) is selected so that the difference in the luminance of the

Device emitted radiation between different areas of the device with different distribution densities of the elements is not more than 20%.

15. A radiation-emitting device according to one of the preceding claims 11 to 14, wherein the insulating elements (310) comprise electrically insulating elements.

16. The radiation-emitting device according to one of the preceding claims 11 to 15, wherein the insulating elements (310) are electrically insulating and interrupt the emission of the radiation in the subregions (330) of the layer sequence in which they are present.

17. A radiation-emitting device according to any one of the preceding claims 15 to 16, wherein the material of the electrically insulating elements (310) is transparent to the emitted radiation.

18. A radiation-emitting device according to one of the preceding claims 11 to 17, wherein the insulating elements (310) have a microscopic size, wherein the size of an insulating element is preferably a few microns, preferably less than 200 microns, preferably less than 100 microns, more preferably less than 20 microns.

The radiation-emitting device according to any one of the preceding claims 11 to 18, wherein the material of the insulating members (310) is selected from a group comprising photoresists, nitrides, ceramics, oxides and organic insulating compounds.

20. Radiation-emitting device according to one of

Claims 15 to 19, wherein the electrically insulating elements (310) are formed linearly.

21. A radiation-emitting device according to the preceding claim, wherein the line-shaped insulating elements (310) are arranged in the form of a periodic structure in the functional layer (300).

22. A radiation-emitting device according to the preceding claim, wherein the periodic structure comprises a grating.

23. A radiation-emitting device according to the preceding claim, wherein the grid has a

Grid spacing (315) between adjacent line-shaped elements, which increases with increasing distance from the first (210) and / or third contact (410).

24. Radiation-emitting device according to the preceding claim, wherein at least between the line-shaped elements (310), the functional layer (300) is arranged, the layer thickness decreases with increasing grid spacing (315) of the elements.

25. Radiation-emitting device according to the preceding claim, wherein the intensity of the emitted radiation decreases with increasing layer thickness of the functional layer (300).

26. A radiation-emitting device according to any one of the preceding claims 11 to 14, wherein the elements are non-transparent to the emitted radiation and reflect and / or absorb the emitted radiation in the subregions (330) of the layer sequence in which they are present.

27. A radiation emitting device according to any one of claims 11 to 14 and 26, wherein the material of the non-transparent elements (320) comprises metals.

28. Radiation-emitting device according to one of the preceding claims 11 to 14 and 26 to 27, wherein the non-transparent to the radiation elements (320) comprise electrically conductive traces.

29. A radiation-emitting device according to the preceding claim, wherein the conductor tracks extend away from the first contact (210) and / or third contact (410) over the first and / or second electrode surface (200, 400).

30. A radiation-emitting device according to one of the preceding claims 28 or 29, wherein the conductor tracks have an electrically insulating layer on the surface to the second electrode surface (400) and to the organic functional layer (300).

31. Radiation-emitting device according to one of the preceding claims 28 or 30, wherein the distribution density of the conductor tracks with increasing distance from the first contact (210) and / or third contact (410) decreases.

32. Radiation-emitting device according to one of the preceding claims 28 to 31, wherein adjacent conductor tracks have different lengths and the length distribution of the conductor tracks starting from the first contact (210) and / or third contact (410) has at least a maximum and a minimum.

33. Radiation-emitting device according to one of the preceding claims 28 to 32, wherein the width of the conductor tracks is a few millimeters, preferably less than 200 microns, preferably less than 100 microns, more preferably less than 20 microns.

34. Radiation-emitting device according to one of the preceding claims 28 to 33, wherein the

Conductor tracks have a thickness in an area less than 200 microns, preferably in a range of 100 nm to 10 microns.

35. Radiation-emitting device according to one of the preceding claims 28 to 34, wherein the conductor tracks pierce the second and / or the first electrode surface (400, 200).

36. The radiation-emitting device according to the preceding claim, wherein the conductor tracks have an insulating layer on the surfaces of the organic functional layer (300) and second or first electrode surface (400, 200).

37. Radiation-emitting device according to one of

Claims 5 to 6, 26 to 31 and 33 to 36, wherein the first and / or third contact (210,410) at all Side of the first and / or second electrode surface (200,400) is present.

38. The radiation-emitting device according to one of claims 26 to 31 and 33 to 37, wherein the conductor tracks are arranged in a periodic structure.

39. A radiation emitting device according to the preceding claim, wherein the periodic structure comprises a grating.

40. A radiation-emitting device according to the preceding claim, wherein the grid has a grid spacing (325) between adjacent conductor tracks, which increases with increasing distance from the first and / or third contact (210, 410).

41. Radiation-emitting device according to the preceding claim, wherein at least between the conductor tracks, the functional layer (300) is present, the layer thickness decreases with increasing grid spacing (325) of the conductor tracks.

42. A radiation-emitting device according to the preceding claim, wherein the intensity of the emitted radiation decreases with increasing layer thickness of the functional layer (300).

43. The radiation-emitting device according to one of claims 1 to 19 and 26 to 36, wherein the first

Electrode surface (200) has a second contact (220) for applying a voltage.

44. The radiation emitting device of claim 1, wherein the second electrode surface has a fourth contact.

45. Device according to one of the preceding claims 43 or 44, are present in the electrically conductive interconnects, which from the second contact (220) and / or fourth contact (420) starting over the first and / or second electrode surface (200, 400 ).

46. The radiation-emitting device according to the preceding claim, wherein the distribution density of the conductor tracks (320) decreases with increasing distance from the first (210) and second contact (220) and / or the third (410) and fourth contact (420) do not overlap the traces originating from the first and second contacts and / or from the third (410) and fourth contacts (420).

47. Radiation-emitting device according to claim 45 or 46, wherein adjacent interconnects have different lengths and the length distribution of the interconnects originates from the first (210) and second contact (220) and / or the third (410) and fourth contact (420). each indicates at least a maximum and a minimum.

48. Radiation-emitting device according to the preceding claim, wherein the maxima and minima of the length distribution of the first (210) and second contact (220) and / or of the third (410) and fourth contact (420) outgoing traces lie opposite.

49. Radiation-emitting device according to claim 47, wherein the maxima and minima of the length distribution of the first (210) and second contact (220) and / or third (410) and fourth contact (420) outgoing conductor tracks are arranged offset from each other.

50. The radiation-emitting device according to claim 28 or 29, wherein the conductor tracks have branches (340).

51. Radiation-emitting device according to the preceding claim, wherein with increasing distance from the first contact (210) and / or from the third contact (410) increasingly more branches (340) are present.

52. Radiation-emitting device according to one of the preceding claims 43, 44, 45, 50 or 51, wherein the thickness and / or width (a) of the conductor tracks with increasing distance from the first contact (210) and / or from the third contact (410 ) decreases.

53. Radiation-emitting device according to one of the preceding claims, wherein in the sub-areas

(330) the electrode material of the first (200) and / or second electrode surface (400) has structuring.

54. The radiation-emitting device according to the preceding claim, wherein the distribution density of the Part areas (330) decreases with increasing distance from the first contact (210).

55. Radiation-emitting device according to one of the preceding claims, wherein in the subregions (330) the at least one functional layer (300) has a reduced conductivity due to lack of doping and / or an increased operating voltage.

56. The radiation-emitting device according to the preceding claim, wherein the distribution density of the partial regions (330) decreases with increasing distance from the first contact (210).

57. Method for producing a radiation-emitting

Device according to one of the preceding claims, comprising the method steps

Arranging a layer sequence on a substrate (100), wherein a plurality of subregions (330) in the

Layer sequence is introduced, which is modified so that the emission of the visible to an external observer radiation is interrupted out of them, wherein the distribution density of these portions varies depending on their distance from the first contact (210).

58. The method according to the preceding claim, wherein between the first (200) and second electrode surface (400) a plurality of insulating (310) and / or radiation-non-transparent elements (320) in the sub-regions (330) with a Aufdampfmaske is produced.

59. The method according to any one of the preceding claims 57 or 58, wherein the first (200) and / or second electrode surface (400) in the subregions (330) is patterned.

60. The method of claim 57, wherein the at least one functional layer (300) is not doped in the subregions (330).