Example embodiments relate to a display device having first and second substrates arranged opposite to each other, a semiconductor device on the first substrate, an organic light emitting element on the first substrate and an optical unit between the organic light emitting element and the second substrate. The display device may be configured to adjust angle viewing modes, e.g., a narrow angle viewing mode and a wide angle viewing mode, by selectively applying a voltage to the organic light emitting element and the optical unit.
1. A display device, comprising:
first and second substrates arranged opposite to each other;
a semiconductor device on the first substrate;
an organic light emitting element on the first substrate, the organic light emitting element includes a first pixel electrode, an organic light emitting layer, and a second pixel electrode in a stacked configuration, the first pixel electrode, the organic light emitting layer, and the second pixel electrode being configured to be electrically connected to the semiconductor device on the first substrate; and
an optical unit between the organic light emitting element and the second substrate, the optical unit including a liquid crystal layer and at least one sub-electrode on the second substrate, the second pixel electrode of the organic light emitting element and the at least one sub-electrode of the optical unit being configured to drive the liquid crystal layer,
wherein the at least one sub-electrode is in a region of the display device opposite a region of the first substrate not having the organic light emitting element, and
wherein a voltage applied to the second pixel electrode interacts separately with the first pixel electrode and the at least one sub-electrode.
2. The display device as claimed in claim 1 , wherein the organic light emitting element is in a light emitting region of the display device.
3. The display device as claimed in claim 1 , wherein the at least one sub-electrode is transparent or semi-transparent.
4. The display device as claimed in claim 2 , wherein the at least one sub-electrode is made using at least one of an indium tin oxide (ITO), an indium zinc oxide (IZO) and a magnesium-silver (MgAg) alloy.
5. The display device as claimed in claim 1 , wherein the liquid crystal layer is between the second pixel electrode and the second substrate.
6. The display device as claimed in claim 1 , wherein the first pixel electrode includes a reflection layer.
7. The display device as claimed in claim 6 , wherein the first pixel electrode is made using at least one of aluminum (Al), an aluminum-alloy (Al-alloy), silver (Ag), a silver-alloy (Ag-alloy), gold (Au) and a gold-alloy (Au-alloy).
8. The display device as claimed in claim 1 , wherein the second pixel electrode is transparent.
9. The display device as claimed in claim 8 , wherein the second pixel electrode is made using at least one of an indium tin oxide (ITO), an indium zinc oxide (IZO) and a magnesium-silver (MgAg) alloy.
10. The display device as claimed in claim 1 , wherein the optical unit is configured to randomly arrange liquid crystal molecules when a voltage is applied to the second pixel electrode and the at least one sub-electrode.
11. The display device as claimed in claim 10 , wherein the optical unit is configured to substantially identically arrange the liquid crystal molecules when no voltage is applied to the second pixel electrode and the at least one sub-electrode.
12. The display device as claimed in claim 1 , wherein the display device is a self-emissive display device.
13. The display device as claimed in claim 1 , wherein the semiconductor device and the organic light emitting element define a display panel between the first and second substrates, the optical unit being positioned between the display panel and the second substrate.
14. The display device as claimed in claim 1 , wherein:
the organic light emitting element is between the semiconductor device and the optical unit, the organic light emitting element directly facing the liquid crystal layer of the optical unit, and
the semiconductor device is between the first substrate and the organic light emitting element.
15. The display device as claimed in claim 1 , wherein the liquid crystal layer is directly between the at least one sub-electrode and an upper electrode of the organic light emitting element.
16. An organic light emitting display device, comprising:
first and second substrates arranged opposite to each other;
a display panel between the first and second substrates, the display panel including a semiconductor device and an organic light emitting element on the first substrate, the organic light emitting element includes a first pixel electrode, an organic light emitting layer, and a second pixel electrode in a stacked configuration, the first pixel electrode, the organic light emitting layer, and the second pixel electrode are configured to be electrically connected to the semiconductor device on the first substrate; and
an optical unit between the display panel and the second substrate, the optical unit including a liquid crystal layer and at least one sub-electrode between the liquid crystal layer and the second substrate, the second pixel electrode and the at least one sub-electrode of the optical unit being configured to drive the liquid crystal layer,
wherein the at least one sub-electrode is in a region of the display device opposite a region of the first substrate not having the organic light emitting element, and
wherein a voltage applied to the second pixel electrode interacts separately with the first pixel electrode and the at least one sub-electrode.
17. The organic light emitting display device as claimed in claim 16 , wherein the optical unit is configured to selectively limit a viewing angle of an image on the display panel.
18. The organic light emitting display device as claimed in claim 16 , wherein the optical unit is external to the display panel.