OLED device with improved efficiency and robustness

1. An organic light-emitting diode (OLED) device, comprising:

a substrate;

an OLED formed on the substrate comprising a first electrode formed over the substrate, one or more layers of organic material, one of which emits light, formed over the first electrode, and a transparent second electrode formed over the one or more layers of organic material, the transparent second electrode and layer(s) of organic light-emitting material having a first refractive index range, wherein one of the first or second electrodes is patterned to form a plurality of separated light-emissive areas;

a transparent cover provided over the OLED through which light from the OLED is emitted, the cover having a second refractive index;

separately formed transparent spacer element particles having a first average size distributed above the transparent second electrode in one or more of the separated light-emissive areas, providing spacing between the transparent second electrode and the cover, and forming a transparent gap between the transparent second electrode and the cover, the transparent gap having a third refractive index lower than each of the first refractive index range and second refractive index; and separately formed transparent light-scattering element particles distributed over, and in contact with, the transparent second electrode between the spacer element particles, having a second average size smaller than the first size and for scattering light emitted by the light-emitting layer.

2. The OLED device of claim 1 , wherein the spacer element particles are deposited on the cover or the OLED.

3. The OLED device of claim 1 , wherein the spacer element particles are in contact with the cover or the OLED or with both the cover and the OLED.

4. The OLED device of claim 1 , wherein the spacer element particles are randomly located over the OLED, regularly distributed over the OLED, or are located between light-emitting portions of the OLED.

5. The OLED device of claim 1 , wherein the spacer element particles comprise titanium dioxide, polymer, or barium oxide.

6. The OLED device of claim 1 , wherein the spacer element particles are light-scattering particles.

7. The OLED device of claim 1 , wherein the spacer element particles are affixed to the cover or OLED with an adhesive.

8. The OLED device of claim 7 , wherein the adhesive is patterned.

9. The OLED device of claim 1 , wherein the gap is filled with a low-index material.

10. The OLED device of claim 1 , wherein the gap is filled with an inert gas, air, nitrogen, or argon.

11. The OLED device of claim 1 , wherein the spacer element particles have an average particle size greater than 2 microns.

12. The OLED device of claim 1 , wherein the light-scattering element particles have an average particle size less than 2 microns.

13. The OLED device of claim 1 , wherein the light-scattering element particles have a refractive index greater than the refractive index of any component of the OLED.

14. The OLED device of claim 1 , wherein the light-scattering element particles and the spacer element particles comprise the same material.

15. The OLED device of claim 1 , wherein the light-scattering element particles and the spacer element particles comprise different materials.

16. The OLED device of claim 1 , wherein the light-scattering element particles and the spacer element particles are deposited in a common step.

17. The OLED device of claim 1 , wherein the light-scattering element particles are deposited within a matrix material.