OLED device having improved output and contrast with light-scattering layer and contrast-enhancement layer
View Patent ↗An organic light-emitting diode (OLED) device, with an OLED formed on a substrate having a first and second electrodes and one or more light-emitting organic material layers formed between the electrodes, the organic material layer(s) having a first optical index and at least one of the electrodes patterned to define light-emitting areas; a cover formed over the OLED. The cover or substrate is transparent and has a second optical index and the light is emitted through the transparent cover or substrate; a light-scattering layer formed between the cover and substrate for scattering light; a low-index element having an optical index lower than the first and second optical indices formed between the scattering layer and the transparent cover or substrate; and a contrast-enhancement layer having a plurality of alternating light-absorbing portions and light-transmissive portions formed in the layer located between the light-scattering layer and the transparent substrate or cover through which light is emitted, wherein a plurality of light-absorbing portions and light-transmissive portions are located in each light-emitting area.
1. An organic light-emitting diode (OLED) device, comprising:
an OLED formed on a substrate having a first electrode formed over the substrate, a second electrode formed over the first electrode, and one or more light-emitting organic material layers formed between the electrodes, wherein at least one of the first or second electrodes is transparent, the organic material layer(s) having a first optical index, and wherein at least one of the first or second electrodes is patterned to define independently controllable light-emitting areas;
a cover formed over the OLED and wherein the cover or substrate is transparent and has a second optical index and the light is emitted through the transparent cover or substrate;
a light-scattering layer formed between the cover and substrate for scattering light;
a low-index element having an optical index lower than the first and second optical indices formed between the scattering layer and the transparent cover or substrate; and
a contrast-enhancement layer comprising a plurality of alternating light-absorbing portions and light-transmissive portions formed in the layer located between the light-scattering layer and the transparent substrate or cover through which light is emitted, wherein a plurality of light-absorbing portions and light-transmissive portions are located in each light-emitting area.
2. The organic light-emitting diode (OLED) device of claim 1 wherein the height of the light-absorbing portions in a vertical dimension orthogonal to the substrate is greater than the minimum width of the light-absorbing portions in a horizontal dimension parallel to the substrate.
3. The organic light-emitting diode (OLED) device of claim 1 wherein the low-index element comprises the light-transmissive portions of the contrast-enhancement layer.
4. The organic light-emitting diode (OLED) device of claim 1 wherein the first electrode is patterned and the first electrode and substrate are transparent.
5. The organic light-emitting diode (OLED) device of claim 4 wherein the contrast-enhancement layer is formed between the transparent substrate and the light-emitting layer(s).
6. The organic light-emitting diode (OLED) device of claim 4 wherein the scattering layer is a transparent scattering layer formed between the transparent substrate and the light-emitting layer(s).
7. The organic light-emitting diode (OLED) device of claim 4 wherein the scattering layer is a reflective scattering layer formed between the cover and the light-emitting layer(s).
8. The organic light-emitting diode (OLED) device of claim 1 wherein the second electrode and the cover are transparent.
9. The organic light-emitting diode (OLED) device of claim 8 wherein the contrast-enhancement layer is formed on the inside of the cover.
10. The organic light-emitting diode (OLED) device of claim 8 wherein the contrast-enhancement layer is formed as a self-supporting film.
11. The organic light-emitting diode (OLED) device of claim 8 wherein the contrast-enhancement layer is formed on or over the transparent electrode.
12. The organic light-emitting diode (OLED) device of claim 8 wherein the scattering layer is a transparent scattering layer formed between the transparent cover and the light-emitting layer(s).
13. The organic light-emitting diode (OLED) device of claim 8 wherein the scattering layer is a reflective scattering layer formed between the substrate and the light-emitting layer(s).
14. The organic light-emitting diode (OLED) device of claim 1 wherein the light-absorbing portions comprise carbon black.
15. The organic light-emitting diode (OLED) device of claim 1 wherein the contrast-enhancement layer comprises a polymer or curable resin.
16. The organic light-emitting diode (OLED) device of claim 1 wherein the contrast-enhancement layer is formed photolithographically.
17. The organic light-emitting diode (OLED) device of claim 1 wherein the contrast-enhancement layer is less than 1 mm thick.
18. The organic light-emitting diode (OLED) device of claim 1 wherein the contrast-enhancement layer is less than 0.5 mm thick.
19. The organic light-emitting diode (OLED) device of claim 1 wherein the height of the light-absorbing portions in a vertical dimension orthogonal to the substrate is greater than the minimum width of the light-transmissive portions in a horizontal dimension parallel to the substrate.
20. The organic light-emitting diode (OLED) device of claim 1 wherein the height of the light-absorbing portions in a vertical dimension orthogonal to the substrate is greater than the minimum width of the light-absorbing portions in a horizontal dimension parallel to the substrate and greater than the minimum width of the light-transmissive portions in a horizontal dimension parallel to the substrate.