Dual mode organic light emitting device and pixel circuit including the same
View Patent ↗A dual mode organic light emitting device and a pixel circuit including the same are disclosed. The dual mode organic light emitting device includes a cathode formed over a substrate, an electron transport layer (ETL) formed over the cathode, an emission layer formed over the electron transport layer (ETL), and an anode formed over the emission layer, wherein the cathode includes a first metal selected from silver (Ag), aluminum (Al), copper (Cu), and gold (Au) and a second metal having a work function of about 4.0 eV or less, and the first metal and the second metal are present at a weight ratio of about 1:1 to about 1:100.
1. A dual mode organic light emitting device, comprising:
a cathode and an anode;
an emission layer interposed between the cathode and the anode; and
an electron transport layer (ETL) interposed between the cathode and the emission layer;
wherein the cathode comprises a first metal selected from silver (Ag), aluminum (Al), copper (Cu), and gold (Au) and a second metal having a work function of about 4.0 eV or less, and
the first metal and the second metal are present at a weight ratio of about 1:10 to about 1:100,
a driving transistor configured to apply a current to the cathode; and
a capacitor configured to apply a voltage corresponding to a data voltage to a gate of the driving transistor,
wherein a first terminal of the driving transistor is electrically connected to the cathode, a first power source is applied to a second terminal of the driving transistor, and a second power source is applied to the anode,
wherein when the dual mode organic light emitting device operates in a normal mode the first power source has a lower voltage level than the second power source, and when the dual mode organic light emitting device operates in a reflective mode, the first power source has a higher voltage level than the second power source.
2. The dual mode organic light emitting device of claim 1 , wherein the second metal comprises at least one of magnesium (Mg), calcium (Ca), ytterbium (Yb), and barium (Ba), or a combination thereof.
3. The dual mode organic light emitting device of claim 1 , wherein the first metal and the second metal are present at a weight ratio of about 1:30.
4. The dual mode organic light emitting device of claim 1 , wherein the first metal and the second metal are present at a weight ratio of about 1:10 to about 1:30.
5. A pixel circuit, comprising:
a dual mode organic light emitting device comprising
a cathode and an anode;
an emission layer interposed between the cathode and the anode; and
an electron transport layer (ETL) interposed between the cathode and the emission layer;
wherein the cathode comprises a first metal selected from silver (Ag), aluminum (Al), copper (Cu), and gold (Au) and a second metal having a work function of about 4.0 eV or less, and the first metal and the second metal are present at a weight ratio between more than about 1:10 and about 1:100 or less;
a P-type driving transistor configured to apply a current to the cathode of the dual mode organic light emitting device; and
a capacitor configured to apply a voltage corresponding to a data voltage to a gate of the driving transistor,
wherein a first terminal of the P-type driving transistor is electrically connected to the cathode of the dual mode organic light emitting device, a first power source is applied to a second terminal of the P-type driving transistor, and a second power source is applied to the anode terminal of the dual mode organic light emitting device,
wherein when the dual mode or organic light emitting device operates in a normal mode, the first power source has a lower voltage level than the second power source, and when the dual mode or organic light emitting device operates in a reflective mode, the first power source has a higher voltage level than the second power source.
6. The pixel circuit of claim 5 , further comprising a first transistor configured to apply the data voltage to the capacitor in response to a scan signal.
7. A pixel circuit, comprising:
a dual mode organic light emitting device comprising:
a cathode and an anode;
an emission layer interposed between the cathode and the anode; and
an electron transport layer (ETL) interposed between the cathode and the emission layer;
wherein the cathode comprises a first metal selected from silver (Ag), aluminum (Al), copper (Cu), and gold (Au) and a second metal having a work function of about 4.0 eV or less, and the first metal and the second metal are present at a weight ratio between more than about 1:10 and about 1:100 or less;
an N-type driving transistor configured to apply a current to an anode of the dual mode organic light emitting device; and
a capacitor configured to apply a voltage corresponding to a data voltage to a gate of the driving transistor,
wherein a first terminal of the N-type driving transistor is electrically connected to the anode of the dual mode or organic light emitting device, a first power source is applied to a second terminal of the N-type driving transistor, and a second power source is applied to a cathode terminal of the dual mode organic light emitting device,
wherein when the dual mode organic light emitting device operates in a normal mode, the first power source has a lower voltage level than the second power source, and when the dual mode organic light emitting device operates in a reflective mode, the first power source has a higher voltage level than the second power source.
8. The pixel circuit of claim 7 , further comprising a first transistor configured to apply the data voltage to the capacitor in response to a scan signal.