Organic light-emitting diode light source comprising a polyester film and a method of improving light extraction from said light source

Patent metadata

Field	Value
Publication number	US-9711758-B2
Application number	US-201514907717-A
Country	US
Kind code	B2
Filing date	Jul 24, 2015
Priority date	Aug 1, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

An organic light-emitting diode (OLED) light source includes, in order:
(i) a biaxially oriented polyester film substrate including light-scattering particles (P 1 ); (ii) optionally an organic planarising coating layer (OPC 1 ); (iii) optionally a barrier layer (B 1 ); (iv) an organic planarising coating layer (OPC 2 ) including light-scattering particles (P 2 ); (v) optionally a barrier layer (B 2 ); and (vi) a multi-layer light-emitting assembly including a first electrode, a light-emitting organic layer and a second electrode;

wherein the OLED light source includes at least one of barrier layers (B 1 ) and (B 2 ).

First claim

The invention claimed is:

1. An organic light-emitting diode (OLED) light source comprising the following layers, in order:
(i) a biaxially oriented polyester film substrate comprising light-scattering particles (P 1 );
(ii) optionally an organic planarising coating layer (OPC 1 );
(iii) optionally a barrier layer (B 1 );
(iv) an organic planarising coating layer (OPC 2 ) comprising light-scattering particles (P 2 );
(v) optionally a barrier layer (B 2 ); and
(vi) a multi-layer light-emitting assembly comprising a first electrode, a light-emitting organic layer and a second electrode;
wherein said OLED light source comprises at least one of barrier layers (B 1 ) and (B 2 ).

2. The OLED light source according to claim 1 which is a bottom-emitting OLED.

3. The OLED light source according to claim 1 which is flexible.

4. The OLED light source according to claim 1 wherein the thickness of the polyester film substrate is in the range of from about 25 to about 250 μm.

5. The OLED light source according to claim 1 wherein said polyester film substrate is selected from a poly(ethylene terephthalate) film and a poly(ethylene naphthalate) film.

6. The OLED light source according to claim 1 wherein said light-scattering particles (P 1 ) are selected from non-voiding inorganic particles, voiding inorganic particles and incompatible resin filler particles, and mixtures thereof.

7. The OLED light source according to claim 1 wherein said light-scattering particles (P 1 ) are selected from non-voiding inorganic particles.

8. The OLED light source according to claim 1 wherein said polyester film substrate comprises light-scattering particles (P 1 ) in an amount of from about 0.01 to about 1.0 vol %, based on the total volume of a polyester film substrate of thickness of 100 μm, wherein concentration ranges at other film thicknesses are calculated according to the formula:
V T =V 100 (100 /T )
wherein:
V T is the particle concentration at a thickness T
V 100 is said particle concentration in said substrate having a thickness of 100 μm.

9. The OLED light source according to claim 1 wherein said polyester film substrate exhibits a haze of at least about 30% and/or a total light transmittance (TLT) of at least about 60%.

10. The OLED light source according to claim 1 wherein said polyester film substrate exhibits a shrinkage of less than 1% at 150° C. over 30 minutes in both the longitudinal and transverse dimensions.

11. The OLED light source according to claim 1 wherein the internal surface of the polyester film substrate exhibits a surface roughness such that the Roughness Average (Ra) value is at least about 50 nm, and/or such that the Root Mean Square Roughness (Rq) value is at least about 50 nm.

12. The OLED light source according to claim 11 wherein said OLED comprises an organic planarising coating layer (OPC 1 ) on a surface of said polyester film substrate and barrier layer (B 1 ) on the surface of said planarising coating layer (OPC 1 ).

13. The OLED light source according to claim 1 wherein the first barrier layer (B 1 ) and the second barrier layer (B 2 ) are independently selected from inorganic barrier layers selected from the group consisting of metals and the oxides, nitrides and sulphides of Groups IVB, VB, VIB, IIIA, IIB, IVA, VA and VIA of the Periodic Table, and combinations thereof; and preferably from SiO 2 , SiO, GeO, Al 2 O 3 , ZnO, ZrO 2 , HfO 2 , AIN, TiN, Si 3 N 4 , Al, Ag, Au, Pt and Ni.

14. The OLED light source according to claim 1 wherein the first barrier layer (B 1 ) and the second barrier layer (B 2 ) are independently selected to exhibit a thickness in the range of from about 2 nm to about 200 nm.

15. The OLED light source according to claim 1 wherein the assembly comprising (i) the polyester film substrate comprising light-scattering particles (P 1 ); (ii) planarising coating layer (OPC 1 ); (iii) optional barrier layer (B 1 ); (iv) organic planarising coating layer (OPC 2 ) comprising light-scattering particles (P 2 ); and (v) optional barrier layer (B 2 ), wherein at least one of said barrier layers is present, exhibits a water vapour transmission rate of less than 10 −3 g/m 2 /day and/or an oxygen transmission rate of less than 10 −3 /mL/m 2 /day.

16. The OLED light source according to claim 1 wherein said organic planarising coating layer(s) is/are independently derived from compositions comprising polymerisable and cross-linkable monomeric compounds and/or polymerisable and cross-linkable oligomeric compounds.

17. The OLED light source according to claim 1 wherein the light-scattering particles (P 2 ) in the organic planarising coating layer (OPC 2 ) are selected from non-voiding inorganic particles, voiding inorganic particles and incompatible resin filler particles, and mixtures thereof.

18. The OLED light source according to claim 1 wherein said organic planarising layer (OPC 2 ) comprises light-scattering particles (P 2 ) in an amount of from about 0.01 to about 1.0 vol %, based on the total volume of an organic planarising layer (OPC 2 ) of thickness of 20 μm, wherein concentration ranges at other layer thicknesses are calculated according to the formula:
V T =V 20 (20 /T )
wherein:
V T is the particle concentration at a thickness T
V 20 is said particle concentration in said organic planarising layer (OPC 2 ) having a thickness of 20 μm.

19. The OLED light source according to claim 1 wherein the thickness of the organic planarising coating layer (OPC 2 ) is from about 5 to about 50 μm.

20. The OLED light source according to claim 1 wherein said light-scattering particles (P 1 ) and (P 2 ) are independently selected to have a volume distributed median particles diameter in the range of from about 150 nm to 500 nm.

21. The OLED light source according to claim 1 wherein the organic planarising layer (OPC 2 ) and/or where present the organic planarising layer (OPC 1 ) further comprise non-light-scattering particles in amounts of up to about 80 wt %, based on the total weight of the layer.

22. The OLED light source according to claim 1 wherein the refractive indices of the barrier layer(s) and the organic planarising coating layer(s) are independently selected to exhibit an RI of from about 1.75 to about 1.85, and the RI of the polyester film substrate is in the range of from about 1.45 to about 1.55.

23. A method for fabricating an OLED light-source as defined in claim 1 comprising the steps of:
(i) providing a polyester film substrate comprising light-scattering particles (P 1 );
(ii) optionally disposing an organic planarising coating layer (OPC 1 ) on a surface of said polyester film substrate;
(iii) optionally disposing a barrier layer (OPC 2 ) on a surface of said polyester film substrate or, where present, on the surface of the organic planarising coating layer (OPC 1 );
(iv) disposing an organic planarising coating layer (OPC 2 ) comprising light-scattering particles (P 2 ) on a surface of the polyester film substrate or on the surface of the barrier layer (B 1 ) where the barrier layer (B 1 ) is present;
(v) optionally disposing a barrier layer (B 2 ) on the surface of the organic planarising coating layer (OPC 2 ); and
(vi) disposing a multi-layer light-emitting assembly comprising a first electrode, a light-emitting organic layer and a second electrode on a surface of the organic planarising coating layer (OPC 2 ) or on the surface of the barrier layer (B 2 )

Assignees

• Dupont Teijin Films U S Ltd Partnership
• TNO
• Nederlandse Organisatie Voor Toegpast Natuurwetenschappelijk Onderzoek Tno

Inventors

• Mackerron Duncan Henry
• Harkema Stephan
• Alexander Ian Keith

Classifications

• H01L51/5206

  Electricity · mapped topic

• H01L51/5253

  Electricity · mapped topic

• H01L2251/5338

  Electricity · mapped topic

• H01L51/56

  Electricity · mapped topic

• H01L51/5268 Primary

  Electricity · mapped topic