UV-protected component for OLEDs

Abstract

The present invention relates to an organic radiation-emitting component with an active organic layer constituted to generate radiation and one or two radiation-output sides, characterised in that, on at least one radiation-output side of the component, a UV protective film is arranged and connected to the component, wherein the UV protective film contains at least one first layer (A) and a second layer (B), wherein the first layer (A) contains 0.01 to 20% by weight, with reference to the total weight of the first layer (A), of a UV absorber, and wherein the second layer (B) contains polycarbonate. Furthermore, the invention relates to the use of a component according to the invention as an organic light-emitting diode, and for lighting, especially for general lighting.

Claims

1. An organic radiation-emitting component comprising an active organic layer constituted to generate radiation and one or two radiation-output sides, wherein, on at least one radiation-output side of the component, a UV protective film is arranged and connected to the component, wherein the UV protective film contains at least one first layer (A) and a second layer (B), wherein the first layer (A) contains 1 to 7.5% by weight, with reference to the total weight of the first layer (A), of (6-[4,6-bis(4-phenylphenyl)-1H-1,3,5-triazin-2-ylidene]-3-(2-ethylhexoxy)cyclohexa-2,4-dien-1-one)-, and wherein the second layer (B) contains polycarbonate, and wherein the first layer (A) comprises polymethacrylate and has a thickness of from ≥10 μm to ≤200 μm, wherein the UV protective film is arranged relative to the active organic layer (2) in such a manner that its first layer (A) faces away from the active organic layer (2) and its second layer (B) faces towards the active organic layer (2) and wherein a gloss level for an angle of 60° from a surface, determined according to EN ISO 2813, of the first layer facing away from the active organic layer (2) is greater than or equal to 70.

2. The component according to claim 1, wherein the UV protective film is free from particles or substances with scattering properties.

3. The component according to claim 1, wherein the UV protective film is free from regions with scattering properties for visible light.

4. The component according to claim 1, wherein the first layer comprises a layer surface extending, on a side of the first layer facing away from the active organic layer (2), over the entire first layer, which is free from regularly arranged geometric structural elements.

5. The component according to claim 1, wherein the first layer (A) and the second layer (B) are constituted as co-extruded.

6. The component according to claim 1, wherein the UV protective film (7) has a thickness of ≥35 μm and ≤1000 μm.

7. The component according to claim 1, wherein the first layer (A) of the UV protective film (7) comprises a coating.

8. The component according to claim 1, wherein the UV protective film (7) is attached to the component (1) by means of an adhesive agent (8), or the UV protective film is laminated onto the component.

9. A method comprising utilizing the component according to claim 1 as an organic light-emitting diode.

Description

(1) Further features, advantages and expediency of the invention are specified in the following description of the exemplary embodiments in conjunction with the FIGS.

(2) FIGS. 1a and 1b show an exemplary embodiment of a radiation-emitting component according to the invention with reference to a simplified schematic cross-sectional view of a “top-emitter”.

(3) FIGS. 2a and 2b show a further exemplary embodiment of a radiation-emitting component according to the invention with reference to a simplified schematic cross-sectional view of a “bottom-emitter”.

(4) FIGS. 3a and 3b show a further exemplary embodiment of a radiation-emitting component according to the invention with reference to a simplified schematic cross-sectional view of a component transparent on both sides.

(5) FIG. 4 shows the lighting picture of an OLED after 5h ageing.

(6) FIG. 5 shows the lighting fixture of an LED after 5 hours ageing test under a xenon lamp (distance 0.5 m).

(7) FIG. 6, shows an embodiment of the radiation emitting component according to the invention.

(8) Identical, similar and similarly operating elements are provided with the same reference numbers in the FIGS.

(9) FIGS. 1a and 1b show an exemplary embodiment of a radiation-emitting component according to the invention with reference to a simplified schematic cross-sectional view of a “top-emitter” and will be explained in greater detail in the following.

(10) The radiation emitting component 1 in FIGS. 1a and 1b is constituted in each case as an OLED. The component 1 comprises an active organic layer 2 embodied to generate radiation. The organic layer 2 is arranged on a substrate 3 of the radiation-emitting component and connected to the latter.

(11) For the charge-carrier injection into the active organic layer 2, the latter can be connected in an electrically conducting manner to a first transparent electrode 4 and a second reflecting electrode 5. Via these electrodes 4, 5, charge carriers—electrons or respectively holes—can be supplied to the organic layer for the generation of radiation through recombination within the organic layer 2. The electrodes 4 and 5 are constituted as layers, and the organic layer is arranged between the electrodes. The electrodes and the organic layer 2 are applied to the substrate 3. By preference, the second electrode 5 is constituted as a reflecting electrode and accordingly at the same time as a reflecting layer. For this purpose, the electrode 5 is preferably constituted to be metallic or alloy based, typically as an aluminium or silver alloy. A separate reflecting layer is not shown explicitly in the FIGS. The second electrode 5 is preferably arranged between the substrate 3 and the organic layer 2. To allow the passage of radiation, the first electrode 4 is expediently constituted to be radiation permeable. For this purpose, the electrode contains, for example, an indium tin oxide (ITO Indium Tin Oxide).

(12) In the case of “top-emitter”, the substrate 3 can be constituted to be radiation permeable or radiation impermeable. The substrate 3 can be manufactured from glass, for example, from Borofloat glass, a metallic film or a metal sheet, for example, made of aluminium or copper, or a polymer material, such as polyethylene terephthalate (PET).

(13) Light passing through the side of the component 1 disposed opposite to the substrate can be output from the component 1, the latter is therefore designated as the radiation-output side 6.

(14) A UV protective film 7 is attached on the radiation-output side 6 of the component 1.

(15) For reasons of visual clarity, the presentation of an encapsulation for the organic layer 2 and the electrodes 4 and 5, which is preferably applied between the UV protective film 7 and the first electrode 4, has not been provided.

(16) An explicit presentation of the electrical contacting of the component has also not been provided. A control circuit of the component can therefore be arranged on the substrate, for example,—optionally inside the encapsulation.

(17) In the exemplary embodiment according to FIG. 1a, the UV protective film 7 is laminated onto the encapsulation disposed over the first electrode 4 and optionally also directly onto the substrate, whereas, in the exemplary embodiment according to FIG. 1b, a separate adhesive-agent layer 8, for example, a glue layer through which the UV protective film 7 is attached, is provided. An Optically Clear Adhesive OCA 8212 manufactured by 3M is used as the adhesive agent 8.

(18) To facilitate the radiation transfer from the component into the UV protective film 7, the material of the second layer (B) of the UV protective film is matched in refractive index to the material of the encapsulation, which is disposed over the first electrode 4. For the second layer (B), a polycarbonate with a refractive index of approximately 1.59 is used. This material is well matched in refractive index for the case that the uppermost layer of the encapsulation represents a protective varnish based on epoxide systems with a refractive index of approximately 1.55 to 1.63.

(19) FIGS. 2a and 2b each show an exemplary embodiment of a radiation-emitting component according to the invention with reference to a simplified schematic cross-sectional view of a “bottom-emitter”.

(20) The radiation emitting component 1 in FIGS. 2a and 2b is constituted in each case as an OLED. The component 1 comprises an active organic layer 2 embodied to generate radiation. The organic layer 2 is arranged on a substrate 3 of the radiation-emitting component and connected to the latter.

(21) For the charge-carrier injection into the active organic layer 2, the latter can be connected in an electrically conducting manner to a first transparent electrode 4 and a second reflecting electrode 5. Via these electrodes 4 and 5, charge carriers—electrons or respectively holes—can be supplied to the organic layer for the generation of radiation through recombination within the organic layer 2. The electrodes 4 and 5 are constituted as layers, and the organic layer is arranged between the electrodes. The electrodes and the organic layer 2 are applied to the substrate 3. By preference, the second electrode 5 is constituted as a reflecting electrode and accordingly at the same time as a reflecting layer. For this purpose, the electrode 5 is preferably constituted to be metallic or as an aluminium or silver alloy. A separate reflecting layer is not shown explicitly in the FIGS. The first electrode 4 is preferably arranged between the substrate 4 and the organic layer 2. To allow the passage of radiation, the first electrode 4 is expediently constituted to be radiation permeable. For this purpose, the electrode contains, for example, an indium tin oxide (ITO Indium Tin Oxide).

(22) The substrate 3 is constituted to be radiation permeable for the radiation generated in the organic layer 2. Visible light is generated by means of the active organic layer 2. For example, a glass substrate made of Borofloat glass can be used as the radiation-permeable substrate.

(23) Light passing through the face of the substrate 3 facing away from to the organic layer 2 can be output from the component 1, the latter is therefore designated as the radiation-output side 6. A UV protective film 7 is attached on the radiation output side 6 of the component 1. The latter is connected to the substrate 3.

(24) For reasons of visual clarity, the presentation of an encapsulation for the organic layer 2, which is preferably arranged on the side of the substrate 4 facing away from the UV protective film 7, has not been provided.

(25) An explicit presentation of the electrical contacting of the component has also not been provided. A control circuit of the component can therefore be arranged on the substrate, for example,—optionally inside the encapsulation.

(26) In the exemplary embodiment according to FIG. 2a, the UV protective film 7 is laminated onto the substrate 3, whereas, in the exemplary embodiment according to FIG. 2b, a separate adhesive-agent layer 8, for example, a glue layer through which the UV protective film 7 is attached, is provided. An Optically Clear Adhesive OCA 8212 manufactured by 3M is used as the adhesive agent 8.

(27) To facilitate the radiation transfer from the substrate 4 into the UV protective film 7, the material of the second layer (B) of the UV protective film is matched in refractive index. For the second layer (B), a polycarbonate with a refractive index of approximately 1.59 is used. This material is well matched in refractive index to a glass substrate, especially a Borofloat glass substrate with a refractive index of approximately 1.54.

(28) FIGS. 3a and 3b each show an exemplary embodiment of a radiation-emitting component according to the invention with reference to a simplified schematic cross-sectional view of an emitter transparent on both sides.

(29) The radiation emitting component 1 is constituted in each case as an OLED. The component 1 comprises an active organic layer 2 embodied to generate radiation. The organic layer 2 is arranged on a substrate 3 of the radiation emitting component and connected to the latter.

(30) For the charge-carrier injection into the active organic layer 2, the latter can be connected in an electrically conducting manner to a first transparent electrode 4 and a further transparent: electrode 402. Via these electrodes 4, 402, charge carriers—electrons or respectively holes—can be supplied to the organic layer for the generation of radiation through recombination within the organic layer 2. The electrodes 4 and 402 are constituted as layers, and the organic layer is arranged between the electrodes. The electrodes and the organic layer 2 are applied to the substrate 3. By preference one of the transparent electrodes 4 or 402 is constituted as a thin metallic film, especially made of silver. The other transparent electrode 4 or 402 preferably contains an indium tin oxide (ITO Indium Tin Oxide).

(31) The substrate 3 is constituted to b radiation permeable for the radiation generated in the organic layer 2. Visible light is generated by means of the active organic layer 2. A glass substrate made of Borofloat glass is used as the radiation permeable substrate.

(32) Light passing through the face of the substrate 3 facing away from to the organic layer 2 and through the side of the component disposed opposite to the substrate can be output from the component 1, these two sides are therefore designated as the radiation-output sides 6 and 602.

(33) According to FIGS. 3a and 3b, UV protective films 7 are attached on both radiation-output sides 6 and 602 of the component 1. Alternatively, a UV protective film 7 can be attached only on one of the two radiation-output sides.

(34) For reasons of visual clarity, the presentation of an encapsulation for the organic layer 2 and the electrodes 4 and 402, which is preferably applied between the UV protective film 7 and the one electrode 4, has not been provided.

(35) An explicit presentation of the electrical contacting of the component has also not been provided. A control circuit of the component can therefore be arranged on the substrate, for example,—optionally inside the encapsulation.

(36) In the exemplary embodiment according to FIG. 3a, the UV protective film 7 is laminated onto the encapsulation disposed over the one electrode 4 and optionally also directly onto the substrate, whereas, in the exemplary embodiment according to FIG. 3b, a separate adhesive-agent layer 8, for example, a glue layer through which the UV protective film 7 is attached, is provided. An Optically Clear Adhesive OCA 8212 manufactured by 3M is used as the adhesive agent 8.

(37) To facilitate the radiation transfer from the substrate 3 into the UV protective film 7 on the radiation output side 6, the material of the second layer (B) of the UV protective film is matched in refractive index to the substrate. For the second layer (B), a polycarbonate with a refractive index of approximately 1.59 is used. This material is well matched in refractive index to a glass substrate, especially a Borofloat glass substrate with a refractive index of approximately 1.54. A glass cover or an encapsulation with a protective varnish based on an epoxide system is preferably disposed on the radiation output side 602 as the uppermost layer. To facilitate the radiation transfer from the component, also on this radiation-output side 602, into the UV protective film 7, the material of the second layer (B) of the UV protective film is matched in refractive index to glass or the epoxide system. For the second layer (B), a polycarbonate with a refractive index of approximately 1.59 is used. This material is well matched in refractive index to the epoxide systems with a refractive index of approximately 1.55 to 1.63 or to the glass cover which behaves in a similar manner to the substrate glass.

(38) In the following, films and their manufacture, which are particularly well-suited for a component according to the invention, especially a component emitting visible light, are described by way of example.

(39) Materials Used:

(40) Makrolon 3108 550115:

(41) High viscosity Bisphenol A Polycarbonate with an MVR of 6.0 cm.sup.3/10 min (according to ISO 1133 at 300° C. and 1.2 kg)

(42) Makrolon 2600 000000:

(43) Medium-viscosity high-viscosity Bisphenol A Polycarbonate with an MVR of 12.5 cm.sup.3/10 min (according to ISO 1133 at 300° C. and 1.2 kg)

(44) Tinuvin 1600:

(45) UV-protective agent manufactured by BASF, Ludwigshafen (formerly Ciba Specialty Chemicals) (biphenyl substituted triazine of the formula I with X═OCH.sub.2CH(CH.sub.2CH.sub.3)C.sub.4H.sub.9)

(46) Tinuvin 360 (2,2′-methylene-bis(6-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl))-phenol):

(47) Low volatility commercial UV protective agent manufactured by BASF, Ludwigshafen, from the group of hydroxyphenyl benzotriazoles.

(48) Plexiglas 8N:

(49) PMMA with an MVR of 3 cm.sup.3/10 min (according to ISO 1133 at 230° C. and 3.8 kg) and a weight-average molecular weight M.sub.w of 124 kg/mol (determined by gel permeation chromatography in tetrahydrofurane at 23° C.; calibration to polystyrene standards of Röhm GmbH & Co. KG).

Example 1

(50) Manufacture of the Tinuvin 1600-UV-Protective-Compounds:

(51) The manufacture of the Tinuvin 1600 UV protective compounds (granulate) was implemented with conventional twin-screw compound extruder with processing temperatures from 230 to 285° C. conventional for polymethylmethacrylate.

(52) A master batch was prepared with the following composition: Plexiglas 8N manufactured by Evonik with a content of 95% by weight. Tinuvin 1600 as a colourless powder with a content of 5% by weight.

(53) 15 kg of powder compound consisting of 10 kg Plexiglas 8N-oversize (mean particle diameter approximately 0.8 mm) and 5 kg Tinuvin 1600, equivalent to 5% by weight) were added to 85 kg Plexiglas 8N in a twin-screw extruder (ZSK 32) with a rotational speed of 190 min.sup.−1 and a throughput of 50 kg/h. The mass temperature was 278° C. and the granulate obtained was clear and transparent.

Example 2

(54) Manufacture of the Compounds Containing Tinuvin® 360 as UV Absorber:

(55) The manufacture of the compound (granulate) containing Tinuvin® 360 as UV absorber was implemented with a conventional twin-screw compounding extruder with processing temperatures from 275 to 300° C. conventional for polycarbonates.

(56) A master batch was prepared with the following composition: 95% by weight polycarbonate Makrolon® 3108 550115 manufactured by Bayer MaterialScience AG 5% by weight Tinuvin® 360 as colourless powder

(57) 10 kg of powder compound consisting of 5 kg Makrolan® 3108-oversize (obtained by milling from the granulate) (mean particle diameter approximately 0.8 mm, measured according to ISO 13320-1 (laser diffraction method)) and 5 kg Tinuvin 360, equivalent to 5% by weight) were added to 90 kg Makrolon® in a twin-screw extruder (ZSK 32) with a rotational speed of 175 min.sup.−1 and a throughput of 50 kg/h. The mass temperature was 306° C. and the granulate obtained was clear and transparent.

(58) Manufacture of a Co-Extruded UV Protective Film:

(59) Film Co-Extrusion:

(60) The plant used comprises an extruder with a screw of 105 mm diameter (D) and a length of 41×D. The screw comprises a degassing zone; a co-extruder for the application of a cover layer with a screw of length 41 D and a diameter of 35 mm to a deflection head a special co-extrusion broad-slot nozzle with 1500 mm width; a triple-roller smoothing calender with horizontal roller arrangement, wherein the third roller can be pivoted by +/−45° relative to the horizontal; a roller track; a device for two-sided application of protective film; an extractor device; a winding station.

(61) The granulate of the base material was supplied to the filling hopper of the main extruder. The melting and conveying of the respective material was implemented in each case in the plastification system cylinder/screw. Both material melts were combined in the co-extrusion nozzle. From the nozzle, the melt passes to the smoothing calender, of which the rollers comprise the temperature named in Table 1. The final forming and cooling of the material takes place on the smoothing calender. For the smoothing of the surfaces, polished chromium rollers were used. Following this, the film is transported through an extractor, the protective film is applied on both sides, after this, the winding of the film is implemented.

(62) The following process parameters were selected:

(63) TABLE-US-00001 TABLE 1 Temperature of the main extruder 295° C. +/− 5° C.   Temperature of the co-extruder 270° C. +/− −5° C. Temperature of the deflection head 285° C. +/− −5° C. Temperature of the nozzle 300° C. +/− −5° C. Rotational speed of the main extruder 60 min.sup.−1 Rotational speed of the co-extruder 31 min.sup.−1 Temperature of roller 1 76° C. Temperature of roller 2 73° C. Temperature of roller 3 140° C. Pull-off rate 14.6 m/min

Example 3

(64) Main Extruder:

(65) A compound with the following composition was mixed: Tinuvin 360-UV-protection-master batch from Example 2 and polycarbonate Makrolon 3108 550115 manufactured by Bayer MaterialScience AG with a content as shown in column 2 “main extruder” in Table 2.

(66) Co-Extruder:

(67) A compound with the following composition was mixed: 100% by weight Tintivin 1600 UV protection master batch from Example 1

(68) From this, a film was extruded with smooth sides on both sides on the transparent polycarbonate layer and the transparent PMMA layer and a total layer thickness of 250 μm.

(69) The thickness of the transparent coating obtained in this manner was determined by means of an Eta SD 30 manufactured by Eta Optik GmbH.

Example 4

(70) Main Extruder:

(71) For the main layer, the following material was used: Polycarbonate Makrolon 3108 550115 manufactured by Bayer MaterialScience AG with a content as shown in column 2 “main extruder” in Table 2

(72) Co-Extruder:

(73) A compound with the following composition was mixed: 100% by weight Tinuvin 360 UV protection master batch from Example 2

(74) From this, a film was extruded with smooth sides on both sides on the transparent polycarbonate layer and the transparent UV-protected polycarbonate layer and a total layer thickness of 250 μm.

(75) TABLE-US-00002 TABLE 2 Main extruder Co-extruder Example 3 235 μm 15 μm 6% Compound from Example 3 + 100% Compound from  94% M. 3108 550115 Example 1 Example 4 220 μm 30 μm 100% M. 3108 550115 100% Compound from Example 3

Example 5

(76) The OLED is a 47.5 mm×125 mm (exterior dimensions) large white-emitting “bottom” emitter according to exemplary embodiment 2b. The active lighting area is 39.4 cm.sup.2. The component has an inorganic thin-layer encapsulation as diffusion barrier. The substrate carrying the thin-layer system was laminated onto a corresponding covering glass. The UV film was glued onto a part of the lighting area (approximately 8 cm.sup.2).

(77) For this purpose, the liner was removed from an adhesive agent (OCA 8212 manufactured by 3M), and the adhesive agent was placed onto the UV protective film. The side from which the liner was removed faced towards the second layer (B) of the UV protective film, which contained polycarbonate. The adhesive agent was laminated onto the UV protective film with a hand roller. A correspondingly large sample was cut out of the UV protective film, and the liner was removed on the side of the adhesive agent facing away from the UV protective film. The UV-protective-film-adhesive-agent composite was aligned with the exposed adhesive-agent side towards the OLED substrate, positioned and laminated onto the OLED with a hand roller.

(78) The lighting picture of this OLED after 5 h ageing test under a xenon lamp (distance 0.5 m) was investigated.

(79) FIG. 4 shows the lighting picture of an OLED after 5 h ageing test under a xenon lamp (distance 0.5 m). Left side provided with a UV protective film according to the invention as shown in Example 3 (A), and right side without film (O). The luminance of the OLED declines significantly in the unprotected region of the active face.

(80) FIG. 5 shows the lighting fixture of an LED after 5 hours ageing test under a xenon lamp (distance 0.5 m). The left upper side (B) is provided with a UV protective film according to Example 4 and the right upper side (O) carries no UV protective film. The right lower side is provided with a UV protective film according to the invention as shown in Example 3 (A) and the left lower side carries no UV protective film (O). The luminance of the OLED declines significantly in the unprotected region of the active face.

(81) Further exemplary embodiments are structured analogously to any one of the previously named exemplary embodiments, wherein the UV protective film (7) is arranged relative to the active organic layer (2) in such a manner that its first layer (A) faces away from the active organic layer (2) and its second layer (B) faces towards the active organic layer (2). The first layer can here comprise a layer surface extending, on a side of the first layer facing away from the active organic layer (2), over the entire first layer, which is free from regularly arranged geometric structural elements. Alternatively or additionally, the first layer can comprise a layer surface extending on a side of the first layer facing away from the active organic layer over the entire first layer, which is free from projections on the layer surface and/or indentations in the layer surface with a height or respectively depth of more than 2 μm, by particular preference more than 1 μm.

(82) FIG. 6, in this respect, shows a further exemplary embodiment of the radiation emitting component according to the invention. This is structured in a similar manner to the exemplary embodiment of FIG. 1a, and comprises all of the features described previously with regard to FIG. 1.

(83) The UV protective film (7) in the present exemplary embodiment is arranged relative to the active organic layer (2) in such a manner that its first layer (A) faces away from the active organic layer (2) and its second layer (B) faces towards the active organic layer. The first layer can here comprise a layer surface extending, on a side of the first layer facing away from the active organic layer (2), over the entire first layer, which is free from regularly arranged geometric structural elements. By preference, a layer surface of the first layer extending on a side facing away from the active layer over the entire first layer is free from projections on the layer surface and/or indentations in the layer surface with a height or respectively depth of more than 2 μm, by particular preference more than 1 μm.

(84) Further exemplary embodiments are structured analogously to any one of the previously named exemplary embodiments, wherein a roughness of a surface of the first layer (A) facing away from the active organic layer (2) is smaller than or equal to 2 μm and/or a gloss level for an angle of 60° of a surface of the first layer facing away from the organic layer (2) is greater than or equal to 70 and/or the UV protective film is free from particles or substances with scattering properties and/or the UV protective film is free from regions with scattering properties.