OLED display architecture

1. A device, comprising:

a first sub-pixel comprising a first organic light emitting device that emits light having a peak wavelength in the visible spectrum of 600-700 nm, further comprising a first emissive layer having a first emissive material, wherein the first emissive material is phosphorescent;

a second sub-pixel comprising a second organic light emitting device that emits light having a peak wavelength in the visible spectrum of 500-600 nm, further comprising a second emissive layer having a second emissive material, wherein the second emissive material is phosphorescent;

a third sub-pixel comprising a third organic light emitting device that emits light having a peak wavelength in the visible spectrum of 400-500 nm and a CIE y-coordinate less than 0.25, further comprising a third emissive layer having a third emissive material, wherein the third emissive material is phosphorescent; and

a fourth sub-pixel comprising a fourth organic light emitting device that emits light having a peak wavelength in the visible spectrum of 400 to 500 nm, further comprising a fourth emissive layer having a fourth emissive material, the fourth emissive material being different than the third emissive material;

wherein the fourth emissive material is fluorescent;

wherein the peak wavelength in the visible spectrum of light emitted by the fourth organic light emitting device is at least 4 nm less than the peak wavelength in the visible spectrum of light emitted by the third organic light emitting device; and

wherein the device has only four different types of sub-pixels.

2. The device of claim 1 , wherein

the third organic light emitting device emits light having a peak wavelength in the visible spectrum of 470-500 nm; and

the fourth organic light emitting device emits light having a peak wavelength in the visible spectrum of 400 to 470 nm.

3. The device of claim 2 , wherein:

the third organic light emitting device emits light having a CIE x-coordinate less than 0.2,and

the fourth the organic light emitting device emits light having a CIE y-coordinate less than 0.15.

4. The device of claim 3 , wherein the CIE coordinates of light emitted by the third organic light emitting device and the CIE coordinates of light emitted by the fourth organic light emitting device are sufficiently different that the difference in the CIE x-coordinates plus the difference in the CIE y-coordinates is at least >0.01.

5. The device of claim 2 , wherein each of the first, second, third and fourth organic light emitting devices have the same surface area.

6. The device of claim 2 , wherein at least one of the first, second, third and fourth organic light emitting devices has a surface area different from another of the first, second, third and fourth organic light emitting devices.

7. The device of claim 2 , wherein the device is part of a full color display.

8. The device of claim 2 , wherein the first, second, third and fourth organic light emitting devices are arranged in a quad pattern.

9. The device of claim 2 , wherein the first, second, third and fourth organic light emitting devices are arranged in a row.

10. The device of claim 1 , wherein the device is a consumer product.

11. The device of claim 1 , wherein:

light emitted by the first organic light emitting device has a 1931 CIE coordinate [X 1 , Y 1 ];

light emitted by the third organic light emitting device has a 1931 CIE coordinate [X 3 , Y 3 ];

at CIE X=0.3, the line joining [X 1 , Y 1 ] and [X 3 , Y 3 ] has a Y value less than 0.275.

12. A device, comprising:

a first sub-pixel comprising a first organic light emitting device that emits light having a peak wavelength in the visible spectrum of 600-700 nm, further comprising a first emissive layer having a first emissive material, wherein the first emissive material is phosphorescent;

a second sub-pixel comprising a second organic light emitting device that emits light having a peak wavelength in the visible spectrum of 500-600 nm, further comprising a second emissive layer having a second emissive material, wherein the second emissive material is phosphorescent;

a third sub-pixel comprising a third organic light emitting device that emits light having a CIE y coordinate less than 0.25, further comprising a third emissive layer having a third emissive material, wherein the third emissive material is phosphorescent; and

a fourth sub-pixel comprising a fourth organic light emitting device that emits light having a CIE y coordinate at least 0.02 less than that of light emitted by the third organic light emitting device, further comprising a fourth emissive layer having a fourth emissive material, the fourth emissive material being different than the third emissive material;

wherein the fourth emissive material is fluorescent; and

wherein the device has only four different types of sub-pixels.

13. The device of claim 12 , wherein:

light emitted by the first organic light emitting device has a 1931 CIE coordinate [X 1 , Y 1 ];

light emitted by the third organic light emitting device has a 1931 CIE coordinate [X 3 , Y 3 ];

at CIE X=0.3, the line joining [X 1 , Y 1 ] and [X 3 , Y 3 ] has a Y value less than 0.275.

14. A method of operating a device having first, second, third and fourth organic light emitting devices such that the device emits light having a desired CIE coordinate, wherein

the first sub pixel comprises a first organic light emitting device that emits light having a peak wavelength in the visible spectrum of 600-700 nm, and further comprises a first emissive layer having a first emissive material, wherein the first emissive material is phosphorescent;

the second sub-pixel comprises a second organic light emitting device that emits light having a peak wavelength in the visible spectrum of 500-600 nm, and further comprises a second emissive layer having a second emissive material, wherein the second emissive material is phosphorescent;

the third sub-pixel comprises a third organic light emitting device that emits light having a peak wavelength in the visible spectrum of 400-500 nm and a CIE y-coordinate less than 0.25, and further comprises a third emissive layer having a third emissive material, wherein the third emissive material is phosphorescent;

the fourth sub-pixel comprises a fourth organic light emitting device that emits light having a peak wavelength in the visible spectrum of 400 to 500 nm, and further comprises a fourth emissive layer having a fourth emissive material, the fourth emissive material being different than the third emissive material;

wherein the device has only four different types of sub-pixels;

wherein the fourth emissive material is fluorescent; and

wherein the peak wavelength in the visible spectrum of light emitted by the fourth organic light emitting device is at least 4 nm less than the peak wavelength in the visible spectrum of light emitted by the third organic light emitting device;

the CIE coordinates of light emitted by the first, second and third devices define a first triangle in the CIE space;

the CIE coordinates of light emitted by the first, third and fourth devices define a second triangle in the CIE space;

the CIE coordinates of light emitted by the second, third and fourth devices define a third triangle in the CIE space;

the method comprising:

emitting light from the first, second and third devices, but not the fourth device, to achieve emission of light with the desired CIE coordinates, if the desired CIE coordinates fall within the first triangle;

emitting light from the first, third and fourth devices, but not the second device, to achieve emission of light with the desired CIE coordinates, if the desired CIE coordinates fall within the second triangle; and

emitting light from the second, third and fourth devices, but not the first device, to achieve emission of light with the desired CIE coordinates, if the desired CIE coordinates fall within the third triangle.

15. The method of claim 14 , wherein

the third organic light emitting device emits light having a peak wavelength in the visible spectrum of 470-500 nm; and

the fourth organic light emitting device emits light having a peak wavelength in the visible spectrum of 400 to 470 nm.

16. The method of claim 14 , wherein:

light emitted by the first organic light emitting device has a 1931 CIE coordinate [X 1 , Y 1 ];

light emitted by the third organic light emitting device has a 1931 CIE coordinate [X 3 , Y 3 ];

at CIE X=0.3, the line joining [X 1 , Y 1 ] and [X 3 , Y 3 ] has a Y value less than 0.275.