WO2010046815A1

WO2010046815A1 - Light emitting tile

Info

Publication number: WO2010046815A1
Application number: PCT/IB2009/054539
Authority: WO
Inventors: Joseph H. A. M. Jacobs; Dirk Hente
Original assignee: Philips Intellectual Property & Standards Gmbh; Koninklijke Philips Electronics N. V.
Priority date: 2008-10-23
Filing date: 2009-10-15
Publication date: 2010-04-29

Abstract

The invention relates to a light emitting tile (1), comprising a transparent carrier body (2), whereas at least one organic light emitting diode (OLED) (3) is arranged on at least one surface (2a, 2b) of the carrier body (2), in order to emit light with a first colour via at least one of the surfaces (2a, 2b), whereas at least one light emitting diode (4a, 4b) is attached to the carrier body (2), irradiating light into the carrier body (2) and which subsequently emits via at least one of the surfaces (2a, 2b) with a colour differing from the colour emitted by said organic light emitting diode (OLED) (3).

Description

LIGHT EMITTING TILE

FIELD OF THE INVENTION

The present invention relates to a light emitting tile, comprising a transparent carrier body, whereas at least one organic light emitting diode is arranged on at least one surface of the carrier body, in order to emit light with a first colour via at least one of the surfaces. Moreover the present invention is directed to a lighting wall comprising a plurality of light emitting tiles.

BACKGROUND OF THE INVENTION

Organic light emitting diodes (OLEDs) are high potential future light sources, in particular for decorative or atmospheric applications. They are expected to become a high efficiency light source on a large area for a cost effective manufacturing. OLEDs can be applied on walls, furniture, bottoms or on the ceiling of rooms and buildings in general. Moreover, OLEDs can be integrated in windows.

During the day, sunlight may enter the room through the OLED window and at night one may touch the switch turning-on the OLED and illuminate the room artificially. When the OLED is applied for decorative or atmospheric applications, it is desirable, to generate coloured patterns on the light emitting surface. For these applications OLEDs are available with structured photo resist devices or the utilization of a current distribution phenomenon may be applied.

The application of OLEDs for atmospheric or decorative elements faces some problems, when being applied in creative lighting atmosphere and animation applications. Techniques to create a colour variable OLEDs exist, but these are still in a very early research stage and most techniques are limited to small areas. Colour variable OLEDs have a very short lifetime and are unreliable and cost intensive. Normal OLEDs can only emit a light comprising a single colour and an atmospheric pattern can not be generated. SUMMARY OF THE INVENTION

Thus, the invention has the objective to eliminate the above mentioned disadvantages. In particular it is an objective of the present invention to provide a light emitting tile, featuring an increased degree of colouring combined with a high reliability and low cost in production.

This objective is achieved by a light emitting tile as taught by claim 1, by a lighting wall comprising a plurality of light emitting tiles as taught by claim 13 and a lighting ile system as taught by claim 14. Preferred embodiments of the invention are defined by the subclaims.

The invention discloses that at least one light emitting diode is attached to the carrier body for irradiating light into the carrier body, which subsequently emits via at least one of the surfaces with a colour differing from the colour emitted by said organic light emitting diode. By combining at least one OLED with at least one light emitting diode

(LED), both irradiating into one single carrier body, a light emitting tile can be provided with a two-coloured or multi-coloured pattern for atmospheric or decorative applications. OLEDs and LEDs feature a different irradiating characteristic, and in its result the light emitting tile provides an inhomogeneous appearance of light. In particular the inhomogeneous appearance of the emitted light is caused by the different light sources irradiating light into the carrier body along different axis as to create a colour mixture.

It is proposed to use a thin OLED in combination with light emitting diodes, even though 2D and 3D formed tile bodies are possible in the sense of the present invention. Advantageously the LEDs are arranged at least one edge of the carrier body to irradiate light into the carrier body. Thus, light is irradiated into the carrier body by the OLED as well as by the at least one LED.

The light irradiated into the carrier body by the LED subsequently emits via at least one of the surfaces of the carrier body, whereas the emitted light via the at least one surface of the carrier body is superimposed by the light, generated by the OLED, which is as well as the light of the LED irradiated into the carrier body. In its result a light emitting tile with an atmospheric pattern can be applied for decorative applications emitting a composite of light.

Advantageously said carrier body features a flat extension and/or a free shaped 2D- or 3D form and preferred a rectangular flat form, whereas a plurality of said light emitting diodes are preferred arranged on opposite edges of the carrier body. As well as an arrangement of the LEDs on two opposite edges, the carrier body can be performed with LEDs on its whole circumference. The shape of said tile is not limited to a rectangular form, but the tile may be performed as a quadrate or it features an orbital, a triangular or any different shape in 2D or 3D formation.

The tile can be preformed as a 3D- volume body, and the arrangement of the at least one OLED and the at least one LED is not limited to one side of the volume body. But preferred said tile comprises a flat and planar form with a flexible or rigid body like a tile, applied on a wall. According to another embodiment said carrier body forms a glass ball or cube body or a free shaped body, which is free shaped or which is geometrically defined. Yet another embodiment of the present invention provides a plurality of light emitting diodes, which preferably are arranged equally spaced to each other on at least one and preferred on two edges of said carrier body. Next to an equally spaced arrangement of the LEDs said LEDs may be arranged in groups on the edges or inside any surface of said carrier body According to yet another embodiment said LEDs may be arranged only at the corners of the body, depending on the desired pattern to be generated and which has to be provided by the light emitting tile.

In order to generate a multi-coloured light emitting tile, the LEDs arranged on a first edge of the carrier body may emit a light with a first colour, which is different to the colour of the light, emitted by the LEDs arranged on the opposite edge of the carrier body. Combined with a third colour emitted by the OLED, an atmospheric light is provided by the tile. Said three colours can result in a colour mixture, whereas by applying an additive mixture of colours a plurality of different colours can be generated. In its preferred embodiment on at least one edge of the carrier body are arranged light emitting diodes providing at least two different colours. The light emitting tile according to the present invention is not limited to a colour separation with a first edge of the carrier body, which is provided with LEDs emitting light with only a first colour and a second edge with LEDs emitting light with only a second colour.

According to the invention the LEDs can be mixed in colour at each separate edge of the carrier body. This means that the arrangement of the LEDs on only one edge may comprise LEDs with a first and with a second colour which are arranged in an alternating manner. For example yellow and blue LEDs may be arranged in one line at one edge of the carrier body. When only the yellow LEDs are switched on, the emitted light is a yellow light, whereas when the blue LEDs are switched on, the emitted light is blue light. But when said yellow LEDs and said blue LEDs are simultaneously switched on, the light appears in a third colour. The present invention is also embodied in light emitting diodes, which are performed as multicolour- LEDs, each suited to emit at least two different colours. So called multicolour- LEDs can emit light with at least two different colours. These multicolour- LEDs can be arranged on each edge of the carrier body or said LEDs are arranged within one surface of the carrier body in order to generate light points or light areas, preferred suited for emitting different colours.

Depending on the way, how said multicolour- LEDs are controlled, said LEDs may emit light with multiple colours, in order to provide a multiple coloured pattern of the light emitting tile. Depending on the control of said LEDs a wave structure, moved patterns and shifting colour areas and shifting brightness can be performed by the light emitting tile.

Combined with the OLED on one surface of the carrier body a multi colour mixture can be performed, whereas on the surface of the carrier body can be applied more than one OLED, whereas said OLEDs may be operated by a special control unit simultaneously or individual. According to yet another embodiment of the invention the LEDs can be arranged to the carrier body as single LEDs or as LED arrays, emitting a single colour or a composition of different colours.

According to yet another embodiment of the present invention a cover substrate is arranged on the top side of the organic light emitting diode (OLED). The cover substrate can be performed as a reflecting substrate to perform the tile as a single- side light emitting tile or the cover substrate is performed as a transparent substrate to perform the tile as a double side emitting tile, when the layer system and in particular the electrodes of the OLEDs, namely the anode and the cathode, are performed transparently. This kind of OLEDs are known as transparent OLEDs.

Moreover the cover substrate may comprise a material, which is deposited onto the at least one OLED as a protecting layer or cover element is performed as a cover element which covers the carrier body and the deposited OLEDs like a closure cap in an offset mounted manner.

The entire tile can be rigid or flexible, whereas when the tile is flexible, it can be used like a "lighting curtain". When the carrier body is performed as a rigid material, a lighting room-partition is created. The organic light emitting diode (OLED) comprises at least one cathode layer and at least one anode layer and at least one organic layer system sandwiched between said cathode layer and said anode layer. The OLED itself is sandwiched between the carrier body and the cover substrate, whereas the cover substrate protects the OLED against moisture and damaging. Said anode layer can be performed as an ITO-electrode and the cathode layer can be performed as an aluminium- layer.

The organic layer system may comprise at least a hole injection layer, an electron blocking layer, an emitting layer, a hole blocking layer and/or an electron transporting layer. The light emitting tile can comprise one single OLED or more than one OLED on each side of the carrier body. In particular the OLED can be performed as an OLED system, which system may comprise an anode layer and a cathode layer, and in between said anode layer and cathode layer may be sandwiched a plurality of emitting layers for emitting light with different colours, e.g. a blue, a green and a red light emitting layer.

The anode layer may be made of an ITO-layer (Indium Tin Oxide- layer) and can be arranged next to the cover substrate, whereas the cathode layer may be made of an aluminium layer, which can be arranged adjacent to the carrier body. When the electrodes are supplied with current, the emitted light is a composition of the single emissions of light within the layer compound.

A different structure of the emitting layers can be patterned layers, e.g. comprising stripe structured layers. The stripes may be arranged parallel to each other in an alternating manner, and can emit e.g. a blue and a yellow light, whereas the layers can emit the light simultaneously or separately. According to yet another layer system of the OLED two or more OLEDs can be stacked onto each other with or without glass substrates in between the layer systems. Thus, the OLEDs can be driven in a series connection or in a parallel connection. According to yet another embodiment an electrode layer of a first OLED can be simultaneously used as an electrode layer of a neighbouring OLED. Thus, one single electrode layer can simultaneously be an anode layer and a cathode layer. In this case, the intermediate layers of electrodes are performed as charging layers. These intermediate electrodes can be connected to different voltage potentials, in order to provide discrete voltages to the different OLEDs.

In order to improve the outcoupling of the light in the carrier body, on the outcoupling surface of the carrier body can be applied at least one outcoupling foil. Next to an outcoupling foil, the carrier body and/or the cover substrate may comprise an outcoupling surface, which is structured by sand blasting or by etching in at least one outcoupling area.

The structuring or the application of an outcoupling foil can improve the outcoupling of the light and in particular the areas can be defined, in which the light couples out of the carrier body. In continuation of the outcoupling effect by applying an outcoupling foil or by structuring the surface of said carrier body or said cover substrate, the light outcoupling area can represent letters, graphics or symbols, which appear in a lighting manner. Next to a local structuring or local foil application, the entire surface may feature the structuring and/or the foil.

Advantageously the tile comprises a thickness of less than 10 mm, preferred less than 5 mm and most preferred less or equal 2 mm. Within the carrier body can be arranged scattering centres for scattering the irradiated light, in order to influence the light appearance of the lighting tile. The scattering centres may be positioned in local areas or within the entire carrier body with a homogenous or carrying density.

The present invention is also directed on a lighting wall comprising a plurality of light emitting tiles. In order to operate the lighting wall comprising said light emitting tiles, a lighting tile system may be provided comprising at least one light emitting tile with an electrical control unit, whereas said electrical control unit is performed to control the at least one organic light emitting diode (OLED) and the at least one light emitting diode (LED), either separately or in a common mode.

In continuation of controlling multiple light emitting tiles, the electrical control unit may be performed to create lighting patterns by controlling the colour and/or the brightness of the at least one organic light emitting diode (OLED) and/or the at least one light emitting diode (LED). Next to a simple illumination of a room, a lighting wall with a plurality of light emitting tiles emitting light in different colours may lead to a special mood and atmosphere within a room.

Additional details, characteristics and advantages of the objective of the invention are disclosed in the depending claims and the following description of the respective figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures - which are only shown in an exemplary fashion - show preferred embodiments of the invention, which will be described in conjunction with the accompanying figures, in which:

Figure 1 shows an embodiment of the inventive light emitting tile in a cross sectional view,

Figure 2 shows a top view of the embodiment of a light emitting tile according to figure 1 with a colour-separated arrangement of LEDs at the opposite edges of the carrier body,

Figure 3 shows another embodiment of arranging coloured LEDs on the edges of the carrier body in an alternating manner with different colours on each edge, whereas scattering centres are shown, Figure 4 shows a cross sectional view of the light emitting tile comprising an outcoupling area in the outcoupling surface of the carrier body and Figure 5 shows another embodiment of the outcoupling surface of the carrier body with an applied outcoupling foil. DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 shows an embodiment of a light emitting tile 1 according to the present invention. The light emitting tile 1 is depicted in a cross section and comprises a transparent carrier body 2, which features a flat extension and can be made of glass or alternatively a flexible synthetic material. Said carrier body 2 is shaped rectangular and features an upper surface 2a and a lower surface 2b. On the upper surface 2a is applied an organic light emitting diode (OLED) 3, which comprises a layer system, deposited on said upper surface 2a of the carrier body 2. The layer system of said OLED 3 comprises at least a cathode layer 7 and an anode layer 6, whereas an organic layer system 8 is sandwiched between said cathode layer 7 and said anode layer 6. When a voltage is applied between the cathode layer 7 and the anode layer 6, the organic layer system 8 can emit light across the entire surface of the OLED 3. The light generated by the OLED 3 irradiates into the carrier body 2 and can be coupled out by passing the lower surface 2b of the carrier body 2 working as an illuminating surface 2b. On the top of the OLED 3 is arranged a cover substrate 5, in order to protect the OLED 3 against oxidation, damaging and moisture.

The two-dimensional carrier body 2 is bordered by edges, whereas a left and a right edge is shown in the cross sectional view. On the edges are arranged light emitting diodes (LED), whereas on the left edge is applied a light emitting diode 4a and on the right edge is applied a light emitting diode 4b. The LEDs 4a and 4b are enclosed within a case 11, whereas within one case 11 the plurality of LEDs 4a and 4b may be enclosed. The LEDs 4a and 4b irradiate light into the carrier body 2, which is indicated by arrows.

In its result the light irradiated by the OLED 3 and the light, irradiated by the LEDs 4a and 4b superimpose within said carrier body 2 and can be coupled out via the outcoupling surface 2b on the bottom side of the carrier body 2. This leads to a light emitting tile 1 which enables coloured patterns across the entire surface of the carrier body 2. These kind of light emitting tiles 1 can be applied in rooms on walls or ceilings, and lead to an impressive atmosphere next to an illumination of the room.

Figure 2 shows a top view of the embodiment of the light emitting tile 1 according to figure 1. The light emitting tile 1 is formed by a carrier body 2, whereas on the top surface of the carrier body 2 an OLED 3 is applied. As shown, on the left and on the right edge of the carrier body is applied a plurality of light emitting diodes (LEDs) 4a and 4b. According to this embodiment on the left side light emitting diodes 4a emitting a light with a first colour are applied. On the right edge are applied a plurality of light emitting diodes 4b, emitting light with a second colour differing from the first colour emitted by the LEDs 4a on the left edge. Combined with the light, emitted by the OLED 3 the light emitting tile 1 generates a smooth colour transition from the left side to the right side. As an example, the left side arranged LEDs 4a may emit blue light whereas the LEDs 4b on the right side can emit red light and across the entire surface of the carrier body 2 a smooth transition between blue and red light appears.

Figure 3 shows another embodiment of the arrangement of the light emitting diodes 4a and 4b at the edges of the carrier body 2. On the left edge as well as on the right edge light emitting diodes 4a and 4b are arranged in an alternating manner. As long as the LEDs 4a emit light with a colour differing from the colour of the light emitted by the LEDs 4b, the colour transition happens between the LEDs 4a and 4b independent from the edge of the carrier body 2. This leads to a varying appearance of the light emitting tile 1 compared to the tile 1 shown in figure 2. In the surface of the tile 1 are shown scattering areas, in which scattering centres 12 are arranged.

The light, irradiated into the carrier body, features a scattering, caused by said scattering centres 12, applied within the material of the carrier body 2. This leads to another emitting distribution of the light, emitting via the outcoupling surface 2b. Preferably the light couples out of the carrier body 2 in these areas. In its result these scattering centres increases the inhomogeneous outcoupling behaviour of the light.

Figure 4 shows a cross section of a light emitting tile 1 with a carrier body 2, whereas on the lower surface 2b of the carrier body 2 is shown an outcoupling area 9. The outcoupling area 9 is generated by a partially structured surface 2b, whereas the structuring can e.g. be performed by sand blasting or etching. When the light is irradiated into the carrier body 2 by the OLED 3 and the LEDs 4a and 4b the light within the carrier body 2 passes the outcoupling surface 2b preferably within the area 9, and letters, symbols or graphics can be generated across the entire surface 2b of the carrier body 2. As well as an irradiation of the light of the OLED 3 into the carrier body 2, the cover substrate 5 can be transilluminated to. Thus, when the cover substrate 5 is transparent next to transparent electrodes, the light emitting tile 1 can be performed as a double side light emitting tile 1. That means that the outcoupling area 9 can also be applied on the cover substrate 5.

Figure 5 shows a light emitting tile 1 with another outcoupling arrangement of the lower outcoupling surface 2b of the carrier body 2. The light generated by the OLED 3 and the light emitting diodes 4a and 4b can be coupled out via the outcoupling surface 2b on which an outcoupling foil 10 is applied. The foil is e.g. glued onto the outcoupling surface 2b and can represent graphics, symbols and/or letters.

The present invention is not limited by the embodiment described above, which is represented as an example only and can be modified in various ways within the scope of protection defined by the depending patent claims. Thus, the invention is also applicable to different embodiments in particular of the design of the carrier body 2 and the arrangement of the LEDs 4a and 4b.

The LEDs 4a and 4b can be arranged in separated manner and are not arranged closed to the of the carrier body 2, e. g. the light can be guided to the edges of the carrier body 2 via light fibres. The fibres may couple out a light into the carrier body 2, whereas the outcoupling may be performed by a prism- structure within the light fibre to generate a line-outcoupling effect along the edge.

LIST OF NUMERALS:

1 light emitting tile

2 carrier body 2a upper surface

2b lower surface, outcoupling surface

3 organic light emitting diode (OLED)

4a light emitting diode (LED)

4b light emitting diode (LED) 5 cover substrate

6 anode layer

7 cathode layer

8 organic layer system

9 outcoupling area 10 outcoupling foil

11 case

12 scattering centre

Claims

CLAIMS:

1. 1. A light emitting tile (1), comprising: a transparent carrier body (2), whereas at least one organic light emitting diode (OLED) (3) is arranged on at least one surface (2a, 2b) of the carrier body (2), in order to emit light with a first colour via at least one of the surfaces (2a, 2b), whereas at least one light emitting diode (4a, 4b) is attached to the carrier body (2), irradiating light into the carrier body (2) and which subsequently emits via at least one of the surfaces (2a, 2b) with a colour differing from the colour emitted by said organic light emitting diode (OLED) (3).

2. A light emitting tile (1) according to claim 1, characterised in that the carrier body (2) features at least one edge, whereas said light emitting diodes (4a, 4b) are arranged on the at least one edge.

3. A light emitting tile (1) according to claim 2, characterised in that said carrier body (2) features a flat extension and/or a free shaped 2D- or 3D form and preferred a rectangular flat form, whereas a plurality of said light emitting diodes (4a, 4b) are preferred arranged on opposite edges of the carrier body (2).

4. A light emitting tile (1) according to one of the previous claims, characterised in that the colour emitted by said light emitting diodes (4a) arranged on a first edge of the carrier body (2) is different to the colour emitted by the light emitting diodes (4b) arranged on a second edge in the carrier body

(2).

5. A light emitting tile (1) according to one of the previous claims, characterised in that a plurality of light emitting diodes (4a, 4b) are arranged equally spaced to each other on at least one edge of the carrier body (2).

6. A light emitting tile (1) according to one of the previous claims, characterised in that on at least one edge of the carrier body (2) are arranged light emitting diodes (4a, 4b) providing at least two different colours.

7. A light emitting tile (1) according to one of the previous claims, characterised in that a cover substrate (5) is arranged on the top side of the organic light emitting diode (OLED) (3), whereas the cover substrate (5) is performed as a reflecting substrate (5) to perform the tile (1) as a single side light emitting tile (1) or said cover substrate (5) is performed as a transparent substrate (5) to perform the tile (1) as a double side light emitting tile (1).

8. A light emitting tile (1) according to one of the previous claims, characterised in that the organic light emitting diode (OLED) (3) comprises at least one anode layer (6), at least one cathode layer (7) and at least one organic layer system (8), sandwiched between said anode layer (6) and said cathode layer (7), whereas different organic layer systems (8) may comprise different emitting colours represented by different colour layers.

9. A light emitting tile (1) according to one of the previous claims, characterised in that said carrier body (2) and/or said cover substrate (5) comprise a glass substrate, whereas said carrier body (2) comprises an outcoupling surface (2b), which is structured by sand blasting or by etching in at least one outcoupling area (9).

10. A light emitting tile (1) according to one of the previous claims, characterised in that on the outcoupling surface (2b) is applied at least one outcoupling foil (10).

11. A light emitting tile (1) according to one of the previous claims, characterised in that the carrier body (2) comprises at least one scattering centre (12) for scattering the irradiated light.

12. A light emitting tile (1) according to one of the previous claims, characterised in that the tile (1) comprises a thickness of less than 10mm, preferred less than 5mm and most preferred less or equal 2mm.

13. A lighting wall comprising a plurality of light emitting tiles (1) according to one of the previous claims 1 to 12.

14. A lighting tile system comprising at least one light emitting tile (1) comprising an electrical control unit, whereas said electrical control unit is performed to control the at least one organic light emitting diode (OLED) (3) and the at least one light emitting diode (4a, 4b) dependent or independent to each other.

15. A lighting tile system according to claim 14, characterised in that the electrical control unit is performed to create lighting patterns by controlling the colour and/or the brightness of the at least one organic light emitting diode (OLED) (3) and/or the at least one light emitting diode (4a, 4b).