LIGHT-EMITTING DEVICE HAVING IMPROVED AMBIENT CONTRAST

• US 20080042146A1
• Filed: 08/18/2006
• Published: 02/21/2008
• Est. Priority Date: 08/18/2006
• Status: Abandoned Application

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Inventors: Cok, Ronald S., Arnold, Andrew D.
• Application Number:
  US11/465,691
• Publication Number:
  US 20080042146A1
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• 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 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

A light emitting device comprising one or more color-change material light-emitting elements, wherein at least one color-change material light-emitting element comprises: a light-emitting layer that emits light including a first frequency range; a light-reflecting layer or surface that reflects light including at least the first frequency range positioned relatively beneath the light-emitting layer; a first color filter positioned relatively above the light-reflecting layer; and a color-change material positioned relatively over the light-emitting layer and over the first color filter; wherein the first color filter passes light having a second frequency range that includes the first frequency range, and not passing a range of visible light having a frequency lower than the first frequency range, and the color-change material converting light of the first frequency range to a third frequency range, the third frequency range including the range of visible light having a frequency lower than the first frequency range not passed by the first color filter. In a preferred embodiment of the invention, the device may comprise a full-color organic light-emitting diode (OLED) device.

Claims

1. A light emitting device comprising one or more color-change material light-emitting elements, wherein at least one color-change material light-emitting element comprises:

a light-emitting layer that emits light including a first frequency range;

a light-reflecting layer or surface that reflects light including at least the first frequency range positioned relatively beneath the light-emitting layer;

a first color filter positioned relatively above the light-reflecting layer; and

a color-change material positioned relatively over the light-emitting layer and over the first color filter;

wherein the first color filter passes light having a second frequency range that includes the first frequency range, and not passing a range of visible light having a frequency lower than the first frequency range, and the color-change material converting light of the first frequency range to a third frequency range, the third frequency range including the range of visible light having a frequency lower than the first frequency range not passed by the first color filter.

2. The device of claim 1 further comprising a second color filter formed over the color-change material, the second color filter passing light including at least a portion of the range of visible light having a frequency lower than the first frequency range not passed by the first color filter, and not passing at least a portion of visible light passed by the first color filter.

3. The device of claim 1 wherein the color-change material light-emitting element comprises an OLED having first and second electrodes, at least one electrode being transparent, wherein the light-emitting layer comprises one or more layers of light-emitting organic material formed between the first and second electrodes.

4. The device of claim 3 wherein one of the electrodes of the OLED comprises the light-reflecting layer or surface positioned relatively beneath the light-emitting layer.

5. The device of claim 1, wherein the first color filter is positioned between the light-reflecting layer or surface and the light-emitting layer.

6. The device of claim 1, wherein the first color filter is positioned relatively above the light-emitting layer.

7. The device of claim 1 wherein the light-emitting layer comprises a backlight unit, and further comprises a transmissive liquid crystal device having two electrodes and a layer of liquid crystal materials located between the electrodes.

8. The device of claim 1 wherein the light-emitting layer comprises a layer of inorganic light-emitting material particles.

9. The device of claim 1 wherein the first frequency range is blue, the second frequency range is blue or cyan, and the third frequency range is green or red.

10. The device of claim 1 wherein the first frequency range is ultra-violet, the second frequency range is ultra-violet or ultra-violet with blue and/or cyan, and the third frequency range is blue, green, or red.

11. The device of claim 1 comprising a plurality of independently-controllable light-emitting elements forming a full-color display device.

12. The display device of claim 11 wherein the independently controllable light-emitting elements are grouped into full-color pixels, each having at least a red, a green, and a blue light emitting element.

13. The device of claim 11 wherein each of the independently-controllable light-emitting elements comprise a common first color filter.

14. The display device of claim 11 wherein the common first color filter is a blue color filter.

15. The display device of claim 11 wherein each of the independently-controllable light-emitting elements comprise a common light-emitting layer.

16. The display device of claim 11 wherein at least one of the independently-controllable light-emitting elements comprises a red color-change light-emitting element, and at least one of the independently-controllable light-emitting elements comprises a green color-change light-emitting element.

17. The display device of claim 16 further comprising a non-color-change light-emitting element that emits blue light.

18. The display device of claim 17 wherein the blue light-emitting element comprises a blue color filter.

19. The device of claim 1 wherein the light-emitting layer emits blue or ultra-violet light.

20. The device of claim 1 wherein the light-emitting layer emits white light.