DE102010063608A1 - Bulb with organic light emitting diode - Google Patents

Abstract

The invention relates to light sources (11; 21; 31; 41; 51; 61) with OLED (12), which have a flat layer structure (14, 15, 16) with at least one emission layer (15) made of organic semiconductor material for generating light emission have, and comprise at least one substrate, in particular a cover substrate (18; 28; 38; 68) and / or a carrier substrate (17; 47), made of translucent material. According to the invention, it is proposed that at least one surface of the substrate directly form an optically effective structure (19; 29; 49; 69) which causes a directional radiation of the light emission by light refraction.

Description

TECHNICAL AREA

The present invention generally relates to bulbs with organic light emitting diode (short: OLED). In particular, the invention relates to such bulbs with planar OLED layer structure with at least one emission layer of organic semiconductor material for generating light emission and with at least one substrate, in particular a cover substrate and / or a carrier substrate of translucent material, which seals the sheet-like layer structure on one side.

In the present case, lighting means are understood to be a device having at least one light source and optionally an optically active structure, such as, for example, a reflector and / or a lens or prism structure.

STATE OF THE ART

OLEDs as planar semiconductor light sources are known. The OLED layer structure is typically applied to a carrier substrate, usually made of glass, and provided with partially transparent electrical conductors (electrodes). A cover substrate, also mostly made of glass, is applied as an outer layer and encloses the actual OLED layer structure in a vacuum-tight manner. Semiconductors made of thin organic material layers are only a few nanometers thin and emit light homogeneously and flatly. OLEDs can radiate unilaterally into a half-space (so-called "opaque OLEDs") or radiate on both sides into both half-spaces separated from the surface of the layer structure. In both cases, the radiation is more or less Lambertian, d. H. undirected (quasi ideal diffuse).

OLEDs are still at the beginning of their development. However, they are expected to make a sustainable contribution to the environment. This is due to their energy efficiency, environmentally friendly materials and low system integration costs.

Currently, OLEDs are already used industrially for backlighting, for example, of small and medium size displays in mobile phones or household appliances. Illuminants with one or more OLEDs are known accordingly. For the lighting industry, however, current OLED lamps are so far only limited. In addition to the costs currently stand in particular the relatively low light output, d. H. The ratio of applied light to electrical power consumed, which includes the EQE (External Quantum Efficiency), and the relatively limited lifetime of the commercial application in the lighting industry. This is especially true for large area applications. However, OLEDs could certainly be used in luminaires. Thus, it is conceivable, for example, to use illuminants with OLEDs in interior lights.

It is now known to use optical films to improve the light output, for example, to counteract the inherent Lambertian radiation. These are microfilm, which can contain different optics. They serve to improve the luminous efficacy and / or to achieve a certain light distribution curve (LVK). For this purpose, such a microfilm with microlenses or microprisms or other micro-optics is mounted on top of the above-mentioned cover substrate. In the case of continuously transparent OLEDs which emit light on both sides, such a foil can also be applied to the carrier substrate. So you can ensure an optimal light extraction on both sides.

However, such applied films obviously reduce the optical efficiency, as they form further transition surfaces (cover substrate / film or carrier substrate / film), which inevitably results in lossy refraction of light. Furthermore, the films absorb some of the usable light.

TECHNICAL PROBLEM / TASK

A technical problem on which the present invention is based is therefore that of improving a generic light source with an OLED in such a way that the luminous efficacy is improved without losses caused by foils or light distribution curve is adapted. In other words, the emitted light should be modified as efficiently as possible in its emission direction.

GENERAL DESCRIPTION OF THE INVENTION

According to the invention, this object is achieved in that, in a luminous means according to the preamble of claim 1, at least one surface of the substrate forms an optically active structure which, by refraction of light, forms a specifically directed d. H. does not cause diffuse radiation of the light emission.

The main feature thus lies in a design in which the optical structure is represented, ie formed, directly by the surface of an already existing substrate. Characterized in that one or both of the existing substrates themselves are provided directly with an optic, unnecessary lossy interfaces are completely avoided.

In one possible embodiment, the optically active structure comprises prisms, preferably linear prisms, which can be relatively easily incorporated into the substrate. In this case, a plurality of asymmetric prisms, preferably parallel linear prisms, are preferred. As a result, a directed emission of the light emission to a specific side across the planar expansion plane of the layer structure can be achieved in each case by the same direction of refraction.

Alternatively or in addition thereto, the surface may represent an optic which comprises one or more lenses, preferably a plurality of lenses, in order to achieve a focusing of the light. Such lenses are formed, for example, by spherical or parabolic sections and cause a directed emission of the light emission towards their respective focal point.

Depending on the requirements, the inner surface, the outer surface or both may be considered as possible surfaces for representing the optical structure of the cover substrate. However, the carrier substrate typically requires a flat inner surface, so that preferably only the outer surface forms an optical structure here. Any combination of these three surfaces are possible, resulting in a variety of design options.

For a double-sided emitting OLED, i. H. If the layer structure is designed to be continuously transparent at least in sections, it is preferred that both the cover substrate and the carrier substrate represent an optically active structure. To reinforce the deflection, the cover substrate on the outer surface as well as on its inner surface can each form an optically active structure, in particular in each case an asymmetric prism structure.

In order to enable a dynamic adaptation of the LVK, an embodiment is preferred in which the layer structure comprises at least one segmented electrode for adjusting the local intensity of the light emission. Accordingly, the at least one surface of the substrate will represent an optically active structure segmented analogously to the electrode, which realizes regions with differently directed radiation of the light emission. As a result, light can be directed through different optics through targeted switching on / off or by changing the intensity.

The proposed bulbs are not exclusively, but especially for use in a lamp, in particular an interior light, and even allow the generation of a desired non-diffuse light distribution curve, d. H. independent of and possibly without appropriate optics on the luminaire housing. A corresponding lamp is the subject of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the invention will be explained with reference to the exemplary and non-limiting embodiments according to the drawings. These show:

1 FIG. 2 shows a schematic cross-section of a first illuminant according to the invention with a single-sidedly emitting (nontransparent) OLED; FIG.

2 FIG. 2: shows a schematic cross-section of a second illuminant according to the invention with a single-side emitting (nontransparent) OLED; FIG.

3 FIG. 2: shows a schematic cross-section of a third illuminant according to the invention with a single-sided emitting (nontransparent) OLED; FIG.

4 FIG. 2: shows a schematic cross-section of a fourth illuminant according to the invention with a (transparent) OLED emitting on both sides; FIG.

5 a schematic cross-section of a fifth illuminant according to the invention with a double-sided emitting (transparent) OLED;

6 FIG. 2: shows a schematic cross section of a further, sixth illuminant with a single-side emitting (nontransparent) OLED, similar to FIG 2 but with a different optically active structure.

In the figures, identical or equivalent components of the various embodiments are provided with identical reference numerals for simplicity.

DETAILED DESCRIPTION ACCORDING TO THE DRAWINGS

1 - 6 show different embodiments of bulbs 11 ; 21 ; 31 ; 41 ; 51 ; 61 in the sense of the invention.

These each comprise an organic light-emitting diode 12 (OLED) in a known manner. The OLED 12 typically includes a flat in a plane across 1 - 6 extensive layer structure with at least one emission layer 15 of organic semiconductor material for generating light emission. So are, for example, OLED 12 With a single layer of polyphenylene vinylene (PPV)) which can be used. The OLED 12 to 1 - 6 However, include a now common multilayer coating structure with the emission layer 15 made of organic semiconductor material and suitable conductor layers 14 . 16 for electrical connection or for creating a pn-diode junction in the intermediate emission layer 15 , The latter is designed in a manner known per se so that in the emission layer 15 light-emitting electron-hole recombination can take place. The structure and mode of action of a single-layer or two-layer (shown) OLED are known per se and in the present case are only relevant in that OLED 12 taken by itself light Lambertian, ie emitting diffuse and non-directional.

The OLEDs 12 include production reasons a carrier substrate 17 ; 47 to which the electrodes or layers 14 . 15 . 16 the OLED 12 applied or applied by suitable methods. Furthermore, the OLEDs include 12 a cover substrate 18 ; 28 ; 38 ; 68 which the layers 14 . 15 . 16 also on the carrier substrate 17 ; 47 sealed vacuum-sealed opposite side. In the case of a one-sided emitting, so-called non-transparent OLED 12 according to the in the 1 - 3 & 6 illustrated embodiments, at least the cover substrate 18 ; 28 ; 38 ; 68 translucent whereas the carrier substrate 17 can be mirrored. For a so-called transparent OLED emitting on both sides 12 to 4 - 5 Both are substrates, ie cover substrate 18 ; 28 ; 38 ; 68 and carrier substrate 47 translucent. To increase the life of the relatively sensitive layers, in particular the emission layer 15 , are carrier substrate 17 ; 47 and cover substrate 18 ; 28 ; 38 ; 68 from a material which the layer structure 14 . 15 . 16 protects against harmful effects, in particular by oxygen and / or water. Currently, mostly rigid glass is used, but there are already suitable flexible materials, especially organic.

In order to achieve a desired light control with minimum losses, is now according to the invention and as from 1 - 6 can be seen, at least one surface of the cover substrate 18 ; 28 ; 38 ; 68 , the carrier substrate 47 or both are formed so that the respective substrate itself is a suitable optically active structure 19 ; 29 ; 49 ; 69 trains or represents. This causes by refraction a directional radiation of light emission. The goal may be, for example, to generate an asymmetrical light distribution curve (LVK) in order to emit the light of the OLED diagonally. This can be z. B. be desired if the lamp or the lamp is not mounted directly on the surface to be illuminated. Suitable optical structures are in particular prisms, as in 1 - 5 shown, or even lenses, as in 6 shown. The cover substrate 18 . 28 . 38 . 68 can work with both internal optical structures 19 , as in 1 , or with external optical structures 29 , as in 2 be provided. The carrier substrate 47 on the other hand, because of production-related reasons, a plane surface for applying the layers 14 . 15 . 16 is required, in principle only outside an optical structure 49 train or represent. The optically active structures 19 ; 29 ; 49 ; 69 Already before making the actual OLED 12 be introduced in the preparation of the respective substrate. This takes place, for example, by the respective surface of the light-permeable substrate 18 . 28 . 38 . 68 ; 17 ; 47 by contrasting processing such as, for example, grinding, or already designed by appropriate shapes in the generation of the substrate is already designed. It should be noted in any case that, in contrast to the prior art, additional lossy transitions are avoided by the substrate or substrates themselves already represent the desired appearance.

The individual embodiments shown are explained in more detail below.

1 shows a light source 11 with non-transparent OLED 12 in which the carrier substrate 17 has conventional design. In the cover substrate 18 however, it is a structure 19 inserted from inside, asymmetric prisms. The prisms of the structure 19 are linear ie extend transversely to the plane of the drawing, preferably in parallel across the width or length of the OLED 12 , Next to the structure 19 has the top substrate 18 not shown flat areas for attachment to the layer structure 14 . 15 . 16 such that in the cavity between optically acting structure 19 and layer structure 14 . 15 . 16 a vacuum is kept. The structure 19 to 1 causes, as illustrated by arrows, by refraction a directional radiation of light emission to one side (left with respect. 1 ) back and forth or obliquely to the flat expansion plane of the layer structure 14 . 15 . 16 , Thus, for example, a substantially uniform emission of the light emission can be achieved. Such an embodiment is particularly suitable when the light source 11 in a lamp horizontally or vertically, for example, wall or close to the ceiling is used, as a result, a specific space area, for example, a workplace can be illuminated.

The light source 21 out 2 differs from 1 in that the cover substrate 28 in 2 an optical structure on the outside, ie of the outer layers 14 . 16 turned away forms. This design simplifies the production of the OLED 12 , however, unlike the bulb offers 11 out 1 no inherent protection of the outside optical structure 29 against mechanical damage.

The light source 31 to 3 essentially represents a combination of the individual optical structures 19 . 29 to 1 - 2 dar. The cover substrate 38 to 3 thus has an optically active structure 29 at its from the layer construction 14 . 15 . 16 remote outer surface and an optically active structure 19 at its for layering 14 . 15 . 16 towards the inner surface. In the illustrated use of equal direction asymmetric prisms in the structures 19 . 29 Overall, a stronger refraction can be achieved at the same angle of the prisms.

At the in 1 - 3 shown opaque OLED 12 can the carrier substrate 17 have conventional structure and, for example, be mirrored to increase the yield. 4 - 5 however, transparent OLEDs show 12 with transverse to the surface extent at least predominantly continuously transparent emission and conduction layers 14 . 15 . 16 and in particular a translucent carrier substrate 47 , In this embodiment, it is also advantageous in the carrier substrate 47 itself as shown an optical structure 49 contribute. Thus, on both sides of the planar OLED 12 The LDCs are designed specifically and as needed to achieve the desired light distribution.

4 shows a light bulb 41 in which exterior in the carrier substrate 47 also linear asymmetric prisms are introduced. The cover substrate 18 corresponds to, for example, the off 1 , In addition to the counter-light direction shown to the left on the deck substrate 18 and to the right on the carrier substrate 47 , Of course, a same direction steering is possible.

Also 5 shows a bulb 41 in which exterior in the carrier substrate 47 linear asymmetric prisms are provided, the top substrate 38 but that one out 3 , ie with a double-sided optical structure 19 . 29 equivalent. Here too, as an alternative to the shown, a directed light direction is possible.

In addition to the combinations shown, of course, other combinations within the meaning of the invention are possible. In particular, the usable optically active structures are not linear asymmetric prisms according to the embodiments in FIGS 1 - 5 limited.

In addition to the above-described embodiments with light deflection targeted to one side, according to the invention, for example, a bundling of the light can be achieved. This may be desirable when illuminating an area under a luminaire or to reduce the luminous intensity at low angles to reduce or avoid unwanted glare effects. In contrast to the above structures 19 . 29 . 49 with asymmetric prisms, symmetrical and preferably linear prisms or a multiplicity of isolated pyramidal prisms are suitable for bundling, for example. Also, one or more lens structures may be provided, which may be formed, for example, by sections having a parabolic or spherical or cylindrical surface.

6 shows in this regard, by way of example, a further embodiment of a lighting means 61 which is basically under construction 1 corresponds and depends only on the type of optical structure used 69 different. In 6 is in the top substrate 68 an optical structure 69 which has a plurality of lenses of spherical surface portions which cause a directed emission of the light emission towards a respective focal point. Alternatively, the convex curvature of the entire surface would be around a single center, ie a single large lens as the optical structure is possible.

The local intensity can, for example, in a conventional manner by suitable matrix structures of in 1 - 6 not shown in detail electrical conductors (electrodes) for the targeted feeding of areas of the emission layer can be controlled. By segmenting the luminous surfaces of the OLED 12 Thus, individual segments can be switched on or off or dimmed. For a transparent and non-transparent OLED 12 it was previously not possible, the light distribution targeted by Lambertian on z. B. asymmetric, or to change from asymmetric to one side in asymmetric to the other side, thereby the LVK of the same bulb 11 ; 21 ; 31 ; 41 ; 51 ; 61 to adapt individually as needed.

In conjunction with analogously to the electrodes suitable segmented optical structures, eg. B. a combination of sections of optically active structure 19 according to 1 and their horizontal mirror image (not shown) can be achieved in a simple way a dynamic adjustment of the LVK of a lamp in operation. So can with respect to 1 z. B. from light extraction to the left side (as in 1 shown) on Lichtauskopplung to the right side (not shown). For this purpose, only an optically active structure segmented analogously to the electrode is concerned 19 ; 29 ; 49 ; 69 required, which has corresponding areas with differently directed light emission. Thus, a desired dynamic adaptability of the LVK can be realized efficiently.

The proposed bulbs significantly increase the applicability of OLEDs in the field of the lighting industry, especially for interior lighting, since now an efficient light source with an inherent, customizable designed LVK is available.

LIST OF REFERENCE NUMBERS

11; 21; 31; 41; 51; 61

Lamp

12

OLED

14

conductive layer

15

emission layer

16

Conduction layer (English electron transport layer, ETL)

17, 47

carrier substrate

18; 28; 38; 68

cover substrate

19; 29; 49; 69

optically effective structure

Claims (10)

Bulbs ( 11 ; 21 ; 31 ; 41 ; 51 ; 61 ) with organic light emitting diode ( 12 ) comprising: a laminar layer structure ( 14 . 15 . 16 ) with at least one emission layer ( 15 ) of organic semiconductor material for generating light emission; at least one substrate, in particular a cover substrate ( 18 ; 28 ; 38 ; 68 ) and / or a carrier substrate ( 17 ; 47 ), of light-permeable material, which seals the laminar layer structure on one side, characterized in that at least one surface of the substrate has an optically active structure ( 19 ; 29 ; 49 ; 69 ), which causes a directed emission of light by refraction of light. Organic light-emitting diode luminous means according to claim 1, characterized in that the surface has an optically active structure ( 19 ; 29 ; 49 ) which comprises prisms, in particular linear prisms. Bulb with organic light-emitting diode according to claim 2, characterized in that the optically active structure ( 19 ; 29 ; 49 ) comprises a multiplicity of asymmetrical prisms, preferably parallel linear prisms, each of which, by refraction of light, directs the emission of light toward one side transversely to the plane of extent of the layer structure ( 14 . 15 . 16 ) cause. Organic light emitting diode according to claim 1 or 2, characterized in that the surface has an optically active structure ( 69 ), which comprises at least one lens, in particular a plurality of lenses, preferably lenses formed by spherical or parabolic sections, which effects a directional emission of the light emission towards a respective focal point. Bulb with organic light-emitting diode according to one of the preceding claims, characterized in that the layer structure ( 14 . 15 . 16 ) on the one side by a carrier substrate ( 17 ; 47 ) and on the opposite side by a cover substrate ( 18 ; 28 ; 38 ; 68 ) and the cover substrate ( 28 ; 38 ; 68 ) forms an optically active structure on its outer surface facing away from the layer structure; and / or the cover substrate ( 18 ; 38 ) forms an optically effective structure on its inner surface facing the layer structure; and / or the carrier substrate ( 47 ) forms an optically effective structure on its outer surface facing away from the layer structure. Bulb with organic light-emitting diode according to claim 5, characterized in that the layer structure is at least partially continuously transparent and both the cover substrate ( 38 ) as well as carrier substrate ( 47 ) an optically active structure ( 19 . 29 . 49 ). Organic light emitting diode according to claim 5 or 6, characterized in that the cover substrate ( 38 ) in each case an optically active structure, in particular in each case an asymmetric prism structure, on its outer surface facing away from the layer structure and on its inner surface facing the layer structure ( 19 . 29 ). Organic light-emitting diode according to one of the preceding claims, wherein the layer structure comprises at least one segmented electrode for changing the local intensity of the light emission, characterized in that the at least one surface of the substrate ( 17 ; 18 ; 28 ; 38 ; 68 ; 47 ) represents an optically active structure segmented analogously to the electrode, which has regions with differently directed radiation of the light emission. Luminaire, in particular interior light, comprising a luminaire housing and at least one luminous means with an organic light-emitting diode according to one of claims 1 to 8. Use of an organic light emitting diode according to one of claims 1 to 8 in a luminaire, in particular an interior light, for producing a desired non-diffuse light distribution curve.

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