Power-efficient RGBW OLED display

• US 9,123,667 B2
• Filed: 10/04/2011
• Issued: 09/01/2015
• Est. Priority Date: 10/04/2011
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: So, Woo-Young, Weaver, Michael
• Primary Examiner(s): Guharay, Karabi
• Application Number:
  US13/252,491
• Publication Number:
  US 20130082589A1
• Time in Patent Office: 1,428 Days
• Field of Search: 313/504, 313/506
• US Class Current: 1/1
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

Embodiments described herein may provide for devices comprising a power efficient RGBW display. In some embodiments, a first device may be provided. The first device may include at least one pixel. The pixel may include a first sub-pixel, a second sub-pixel, a third sub-pixel, and a fourth sub-pixel. The first sub-pixel may include a first color filter in optical communication with a first organic light emitting device. The second sub-pixel may include a second color filter in optical communication with a second organic light emitting device. The third sub-pixel may include a third color filter in optical communication with a third organic light emitting device. The fourth sub-pixel may include a fourth organic light emitting device and emits near white light. At least one of the first sub-pixel or the second sub-pixel may include a color conversion layer in optical communication with the first or second organic light emitting device.

Claims

1. A first device comprising:

at least one pixel, wherein the pixel comprises a first sub-pixel, a second subpixel, a third sub-pixel, and a fourth sub-pixel, wherein;

the first sub-pixel comprises;

a first organic light emitting device;

a first color filter in optical communication with the first organic light emitting device, wherein the first color filter is adapted to preferentially pass light from the first organic light emitting device having a peak wavelength in the visible spectrum between 580 and 700 nm; and

a first color conversion layer, wherein;

the first color conversion layer is in optical communication with the first organic light emitting device and is disposed between the first organic light emitting device and the first color filter; and

the first color conversion layer comprises a material having an absorption spectrum having a peak wavelength that is less than 600 nm and an emission spectrum having a peak wavelength that is between 580 and 700 nm;

the second sub-pixel comprises;

a second organic light emitting device;

a second color filter in optical communication with the second organic light emitting device, wherein the second color filter is adapted to preferentially pass light from the second organic light emitting device having a peak wavelength in the visible spectrum between 500 and 580 nm; and

a second color conversion layer, wherein;

the second color conversion layer is in optical communication with the second organic light emitting device and is disposed between the second organic light emitting device and the second color filter; and

the second color conversion layer comprises a material having an absorption spectrum having a peak wavelength that is less than 500 nm and an emission spectrum having a peak wavelength that is between 500 and 580 nm;

the third sub-pixel comprises;

a third organic light emitting device; and

a third color filter in optical communication with the third organic light emitting device, wherein the third color filter is adapted to preferentially pass light from the third organic light emitting device having a peak wavelength in the visible spectrum between 400 and 500 nm;

the fourth sub-pixel comprises a fourth organic light emitting device and emits near white light having a point on the CIE 1976 UCS (L′

, u′

, v′

) color space chromaticity diagram that lies within a duv distance of 0.010 from the Planckian locus,

wherein the first, the second, the third, and the fourth organic light emitting device each comprise exactly two organic emitting materials, a first organic emitting material and a second organic emitting material;

wherein the first organic emitting material has an emissive spectrum having a peak wavelength between 500 and 630 nm;

wherein the second organic emitting material has an emissive spectrum having a peak wavelength between 400 and 500 nm; and

wherein the first color conversion layer and the second conversion layer have a photoluminescence quantum yield (PLQY) of at least 40%.

2. The first device of claim 1, wherein the chromaticity of the fourth organic light emitting device is substantially the same as the chromaticity of the light emitted by the fourth sub-pixel.

3. The first device of claim 1,

wherein the first device is a display having a white balance;

wherein the white balance has a first point on the CIE 1976 UCS (L′

, u′

, v′

) color space chromaticity diagram;

wherein the fourth sub-pixel emits light having a second point on the CIE 1976 UCS (L′

, u′

, v′

) color space chromaticity diagram; and

wherein the difference between the first point and the second point has a duv value less than 0.10.

4. The first device of claim 1,

wherein the first organic emitting material has an emissive spectrum having a peak wavelength between 520 and 630 nm;

wherein the second organic emitting material has an emissive spectrum having a peak wavelength between 400 and 500 nm.

5. The first device of claim 4, wherein the first organic emitting material has an emissive spectrum having a full width at half maximum (FWHM) of less than 100 nm.

6. The first device of claim 4, wherein the first color conversion layer has an absorption spectrum such that at least approximately 10% of the light emitted by the first emitting material is absorbed.

7. The first device of claim 4, wherein the first color conversion layer has an absorption spectrum such that at least approximately 30% of the light emitted by the first emitting material is absorbed.

8. The first device of claim 4, wherein the second color conversion layer has an absorption spectrum such that at least approximately 10% of the light emitted by the second emitting material is absorbed.

9. The first device of claim 8, wherein the second color conversion layer has an absorption spectrum such that at least approximately 30% of the light emitted by the second emitting material is absorbed.

10. The first device of claim 1,

wherein the first organic emitting material has an emission spectrum such that it emits yellow light that has a first point on the CIE 1931 XYZ color space chromaticity diagram within a first area defined by CIE_x=0.400 to 0.600, CIE_y=0.400 to 0.600;

wherein the second organic emitting material has an emission spectrum such that it emits blue light that has a second point on the CIE 1931 XYZ color space chromaticity diagram within a second area defined by CIE_x=0.100 to 0.200, CIE_y=0.050 to 0.300, such that when a line is drawn between the first point and the second point, it passes through a desired white area defined on the CIE 1931 XYZ color space chromaticity diagram to be within CIE_x=0.25 to 0.4, CIE_y=0.25 to 0.4; and

wherein a concentration of the first and second organic emitting materials is such that the light produced by the first, the second, the third, and the fourth organic light emitting devices is at a third point on the CIE 1931 XYZ color space chromaticity diagram that is within the desired white area.

11. The first device of claim 1, wherein:

the first sub-pixel further comprises a third color conversion layer, wherein;

the third color conversion layer is in optical communication with the first organic light emitting device and is disposed between the first organic light emitting device and the first color filter; and

the third color conversion layer comprises a material having an absorption spectrum having a peak wavelength that is less than 500 nm and an emission spectrum having a peak wavelength between 500 and 580 nm.

12. A first device comprising:

at least one pixel, wherein the pixel comprises a first sub-pixel, a second subpixel, a third sub-pixel, and a fourth sub-pixel, wherein;

the first sub-pixel comprises;

a first organic light emitting device; and

a first color filter in optical communication with the first organic light emitting device, wherein the first color filter is adapted to preferentially pass light from the first organic light emitting device having a peak wavelength in the visible spectrum between 580 and 700 nm;

the first sub-pixel comprises a first color conversion layer, wherein;

the first color conversion layer is in optical communication with the first organic light emitting device and is disposed between the first organic light emitting device and the first color filter; and

the first color conversion layer comprises a material having an absorption spectrum having a peak wavelength that is less than 600 nm and an emission spectrum having a peak wavelength that is between 580 and 700 nm;

the second sub-pixel comprises;

a second organic light emitting device; and

a second color filter in optical communication with the second organic light emitting device, wherein the second color filter is adapted to preferentially pass light from the second organic light emitting device having a peak wavelength in the visible spectrum between 500 and 580 nm;

a second color conversion laver, wherein;

the second color conversion layer is in optical communication with the second organic light emitting device and is disposed between the second organic light emitting device and the second color filter; and

the second color conversion layer comprises a material having an absorption spectrum having a peak wavelength that is less than 500 nm and an emission spectrum having a peak wavelength that is between 500 and 580 nm

the third sub-pixel comprises;

a third organic light emitting device; and

a third color filter in optical communication with the third organic light emitting device, wherein the third color filter is adapted to preferentially pass light from the first organic light emitting device having a peak wavelength in the visible spectrum between 400 and 500 nm;

the fourth sub-pixel comprises a fourth organic light emitting device and emits near white light having a point on the CIE 1976 UCS (L′

, u′

, v′

) color space chromaticity diagram that lies within a duv distance of 0.010 from the Planckian locus,

wherein the first, the second, the third, and the fourth organic light emitting devices each comprise exactly two organic emitting materials, a first organic emitting material and a second organic emitting material;

wherein the first organic emitting material has an emission spectrum such that it emits yellow light that has a first point on the CIE 1931 XYZ color space chromaticity diagram within a first area defined by CIE_x=0.400 to 0.600, CIE_y=0.400 to 0.600;

wherein the second organic emitting material has an emission spectrum such that it emits blue light that has a second point on the CIE 1931 XYZ color space chromaticity diagram within a second area defined by CIE_x=0.100 to 0.200, CIE_y=0.050 to 0.300, such that when a line is drawn between the first point and the second point, it passes through a desired white area defined on the CIE 1931 XYZ color space chromaticity diagram to be within CIE_x=0.25 to 0.4, CIE_y=0.25 to 0.4; and

wherein a concentration of the first and second organic emitting materials is such that the light produced by the first, the second, the third, and the fourth organic light emitting devices is at a third point on the CIE 1931 XYZ color space chromaticity diagram that is within the desired white area.