Light-emitting device
There is provided a light emitting device which enables a color display with good color balance. A triplet compound is used for a light emitting layer of an EL element that emits red color, and a singlet compound is used for a light emitting layer of an EL element that emits green color and a light emitting layer of an EL element that emits blue color. Thus, an operation voltage of the EL element emitting red color may be made the same as the EL element emitting green color and the EL element emitting blue color. Accordingly, the color display with good color balance can be realized.
1. A display module comprising:
a substrate;
a first light-emitting layer, a second light-emitting layer, and a third light-emitting layer over the substrate;
an electrode over the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer; and
an insulating film over the electrode,
wherein the first light-emitting layer comprises a first triplet compound capable of emitting red light,
wherein the second light-emitting layer comprises a second triplet compound capable of emitting green light, and
wherein the third light-emitting layer comprises a singlet compound capable of emitting blue light.
2. The display module according to claim 1 , wherein the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer do not overlap with one another.
3. The display module according to claim 1 , wherein the electrode has a light transmitting property.
4. The display module according to claim 1 , wherein the first triplet compound and the second triplet compound contain iridium or platinum.
5. The display module according to claim 1 , wherein the insulating film comprises a film selected from a carbon film, a silicon nitride film, and a silicon nitride oxide film.
6. The display module according to claim 1 , wherein light emitting brightness of the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer is the same as one another.
7. A display module comprising:
a substrate;
a first transistor;
a second transistor;
a third transistor;
a first pixel electrode electrically connected to the first transistor;
a second pixel electrode electrically connected to the second transistor;
a third pixel electrode electrically connected to the third transistor;
a bank over the first pixel electrode, the second pixel electrode, and the third pixel electrode;
a first light-emitting layer over the first pixel electrode;
a second light-emitting layer over the second pixel electrode;
a third light-emitting layer over the third pixel electrode;
an electrode over the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer; and
an insulating film over the electrode,
wherein the first light-emitting layer comprises a first triplet compound capable of emitting red light,
wherein the second light-emitting layer comprises a second triplet compound capable of emitting green light, and
wherein the third light-emitting layer comprises a singlet compound capable of emitting blue light.
8. The display module according to claim 7 , wherein the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer do not overlap with one another.
9. The display module according to claim 7 , wherein the electrode has a light transmitting property.
10. The display module according to claim 7 , wherein the first triplet compound and the second triplet compound contain iridium or platinum.
11. The display module according to claim 7 , wherein the insulating film comprises a film selected from a carbon film, a silicon nitride film, and a silicon nitride oxide film.
12. The display module according to claim 7 , wherein light emitting brightness of the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer is the same as one another.