OLED device having improved contrast

• US 7,402,951 B2
• Filed: 09/27/2005
• Issued: 07/22/2008
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Cok, Ronald S.
• Primary Examiner(s): Patel; Vip
• Application Number:
  US11/235,832
• Publication Number:
  US 20070069635A1
• Time in Patent Office: 1,029 Days
• Field of Search: 313504-506, 313/512
• US Class Current: 313/506
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: H10K 50/865 comprising light absorbing layers, e.g. light-blocking layers
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 59/877 comprising scattering means
• CPC Class Codes: H10K 59/8792 comprising light absorbing layers, e.g. black layers

Abstract

An organic light-emitting diode (OLED) device, comprises: a first electrode and a second transparent electrode having one or more organic layers formed there-between, at least one organic layer being light-emitting; and a contrast enhancement element formed on a side of the second transparent electrode opposite the organic layers, wherein the contrast enhancement element comprises a patterned reflective layer for reflecting emitted light and a corresponding light-absorbing layer for absorbing ambient light, wherein the reflective layer is located between the light-absorbing layer and the second transparent electrode and wherein the corresponding layers form one or more transparent openings through the reflective and light-absorbing layers so that light emitted by the light-emitting organic layer passes through the transparent openings.

Claims

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

a first electrode and a second transparent electrode having one or more organic layers formed there-between, at least one organic layer being light-emitting; and

a contrast enhancement element formed on a side of the second transparent electrode opposite the organic layers, wherein the contrast enhancement element comprises a patterned reflective layer for reflecting emitted light and a corresponding lift-absorbing layer for absorbing ambient light, wherein the patterned reflective layer is located between the light-absorbing layer and the second transparent electrode and wherein the corresponding layers form one or more transparent openings though the reflective and light-absorbing layers so that light emitted by the light-emitting organic layer passes through the transparent openings, and wherein the one or more transparent openings through the reflective and light-absorbing patterned layers include holes.

2. The organic light-emitting diode (OLED) device of claim 1, further comprising a substrate wherein the first and second electrodes and organic layers are located between the substrate and the contrast enhancement element.

3. The organic light-emitting diode (OLED) device of claim 1, further comprising a substrate wherein the contrast enhancement element is located between the substrate and the second electrode.

4. The organic light-emitting diode (OLED) device of claim 1, further comprising a scattering layer located between the contrast enhancement element and the second electrode.

5. The organic light-emitting diode (OLED) device of claim 1, further comprising a scattering layer and wherein the first and second electrodes and organic layers are located between the contrast enhancement element and the scattering layer.

6. The organic light-emitting diode (OLED) device of claim 1, further comprising one or more color filters located on either side of the contrast enhancement element or in at least one of the openings.

7. The organic light-emitting diode (OLED) device of claim 1, further comprising a layer of color filters located between the second electrode and the contrast enhancement element.

8. The organic light-emitting diode (OLED) device of claim 1, further comprising a scattering layer and a layer of color filters and wherein the layer of color filters are located between the scattering layer and the contrast enhancement element.

9. The organic light-emitting diode (OLED) device of claim 1, wherein the first electrode is reflective.

10. The organic light-emitting diode (OLED) device of claim 1, wherein the first electrode comprises multiple layers including a transparent layer and a reflective layer, and wherein the reflective layer comprises a scattering surface or wherein the first electrode further comprises a scattering layer between the transparent and reflective layers.

11. The organic light-emitting diode (OLED) device of claim 1, wherein the contrast enhancement element comprising a transparent film on or in which the light-absorbing layer and the reflective layers are patterned.

12. The organic light-emitting diode (OLED) device of claim 1, wherein the sides of the holes are reflective and/or coated with a reflective material.

13. The organic light-emitting diode (OLED) device of claim 1, wherein the contrast enhancement element is formed on or adjacent to the transparent electrode or a protective layer formed on the transparent electrode.

14. The organic light-emitting diode (OLED) device of claim 1, wherein the light absorbing layer comprises carbon black or a circular polarizer.

16. The organic light-emitting diode (OLED) device of claim 1, wherein the reflective layer forms a planar reflective surface, an angled segmented reflective surface, or a curved reflective surface.

17. The organic light-emitting diode (OLED) device of claim 1, wherein the first or second electrode is patterned to form multiple light-emitting areas each having first and second distances in at least two dimensions and wherein the openings in the contrast enhancement element are spaced apart by a distance equal to or smaller than the distance in each dimension.

18. The organic light-emitting diode (OLED) device of claim 1, wherein the first or second electrode is patterned to form multiple light-emitting areas and wherein one or more openings in the contrast enhancement element are located over each light-emitting area.

19. The organic light-emitting diode (OLED) device of claim 1, wherein the first and second electrodes form one or more light-emitting areas and wherein a plurality of openings in the contrast enhancement element are located over each light-emitting area.

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

a first electrode and a second transparent electrode having one or more organic layers formed there-between, at least one organic layer being light-emitting;

a contrast enhancement element formed on a side of the second transparent electrode opposite the organic layers, wherein the contrast enhancement element comprises a patterned reflective layer for reflecting emitted light and a corresponding light-absorbing layer for absorbing ambient light, wherein the patterned reflective layer is located between the light-absorbing layer and the second transparent electrode and wherein the corresponding layers form one or more transparent openings through the reflective and light-absorbing layers so that light emitted by the light-emitting organic layer passes through the transparent openings; and

a substrate or a cover through which light is emitted and a scattering layer, wherein the openings in the contrast enhancement element form a low-index element having a refractive index lower than the refractive index range of the organic layers and of the substrate or cover through which light is emitted, and wherein the low-index element is between the scattering layer and the substrate or cover through which light is emitted.