Light emitting device and manufacturing method thereof

• US 20030094612A1
• Filed: 11/06/2002
• Published: 05/22/2003
• Est. Priority Date: 11/22/2001
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Corp Semiconductor Energy Lab
• Inventors: Seo, Satoshi, Yamazaki, Shunpei
• Granted Patent: US 6,876,007 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/80 Constructional details
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/814 combined with auxiliary electrodes, e.g. ITO layer combined with metal lines
• CPC Class Codes: H10K 50/824 combined with auxiliary electrodes
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/17 Passive-matrix OLED displays
• CPC Class Codes: H10K 59/805 Electrodes
• CPC Class Codes: H10K 71/841 Applying alternating current [AC] during manufacturing or treatment

Abstract

A light emitting device is provided, which uses alternating current drive as a method of driving the light emitting device, and in which light emission is always obtained when voltages having different polarities are alternately applied, and a method of manufacturing the light emitting device is also provided. A first light emitting element made from an anode, an organic compound layer, and a cathode, and a second electrode made from an anode, an organic compound layer, and a cathode are formed. The light emitting elements are formed sandwiching the same organic compound layer. The anode of the first light emitting element and the anode of the second light emitting element, and the cathode of the first light emitting element and the cathode of the second light emitting element, are formed on opposite sides of the organic compound layer, respectively, thus sandwiching the organic compound layer. Note that voltages having an inverse polarity are applied alternately by the alternating current drive, and therefore light can always be emitted by any one of the first light emitting element or the second light emitting element.

Claims

1. A light emitting device comprising:

a first light emitting element having a first pixel electrode, an organic compound layer and a first opposing electrode; and

a second light emitting element having a second pixel electrode, the organic compound layer and a second opposing electrode,

wherein the first pixel electrode and the second pixel electrode are formed on a first surface,

wherein the first opposing electrode and the second opposing electrode are formed on a second surface;

wherein the first pixel electrode and the second opposing electrode are any one of anodes and cathodes, and

wherein the second pixel electrode and the first opposing electrode are the other of the anodes and the cathodes.

2. A light emitting device according to claim 1, wherein the organic compound layer comprises a bipolar material having hole transporting characteristics and electron transporting characteristics.

3. A light emitting device according to claim 1, wherein the organic compound layer comprises a material having hole transporting characteristics and a material having electron transporting characteristics.

4. A light emitting device according to claim 1, wherein the light emitting device is selected from the group consisting of a display device, a digital still camera, a notebook personal computer, a mobile computer, a portable image playback device provided with a recording medium, a goggle display, a video camera and a portable telephone.

5. A light emitting device comprising:

a first TFT formed on an insulating surface;

a second TFT formed on the insulating surface;

a first insulating film formed over the first TFT and the second TFT;

a first pixel electrode formed on the first insulating film;

a second pixel electrode formed on the first insulating film;

a second insulating film formed covering a connection portion between the first pixel electrode and the first TFT, and a connection portion between the second pixel electrode and the second TFT;

an organic compound layer formed on the first pixel electrode and the second pixel electrode;

a first opposing electrode formed on the organic compound layer; and

a second opposing electrode formed on the organic compound layer,

wherein the first pixel electrode and the second opposing electrode are any one of anodes and cathodes,

wherein the second pixel electrode and the first opposing electrode are the other of the anodes and the cathodes.

6. A light emitting device according to claim 5, wherein the organic compound layer comprises a bipolar material having hole transporting characteristics and electron transporting characteristics.

7. A light emitting device according to claim 5, wherein the organic compound layer comprises a material having hole transporting characteristics and a material having electron transporting characteristics.

8. A light emitting device according to claim 5, wherein the light emitting device is selected from the group consisting of a display device, a digital still camera, a notebook personal computer, a mobile computer, a portable image playback device provided with a recording medium, a goggle display, a video camera and a portable telephone.

9. A light emitting device comprising:

a first TFT formed on an insulating surface;

a second TFT formed on the insulating surface;

a first insulating film formed over the first TFT and the second TFT;

a first pixel electrode and a second pixel electrode formed on the first insulating film;

an second insulating film formed covering a connection portion between the first pixel electrode and the first TFT, and a connection portion between the second pixel electrode and the second TFT;

an organic compound layer formed on the first pixel electrode and the second pixel electrode;

a first opposing electrode formed on the organic compound layer; and

a second opposing electrode formed on the organic compound layer,

wherein the first TFT and the second TFT each have a source region and a drain region,

wherein the first pixel electrode comprises a first electrode,

wherein the second pixel electrode comprises a second electrode and a first auxiliary electrode,

wherein the first electrode and the second electrode are electrically connected to one of the source region or the drain region, in an opening portion formed in the first insulating film,

wherein the first pixel electrode and the second opposing electrode are any one of anodes and cathodes, and

wherein the second pixel electrode and the first opposing electrode are the other of the anodes and the cathodes.

10. A light emitting device according to claim 9, wherein the organic compound layer comprises a bipolar material having hole transporting characteristics and electron transporting characteristics.

11. A light emitting device according to claim 9, wherein the organic compound layer comprises a material having hole transporting characteristics and a material having electron transporting characteristics.

12. A light emitting device according to claim 9, wherein the light emitting device is selected from the group consisting of a display device, a digital still camera, a notebook personal computer, a mobile computer, a portable image playback device provided with a recording medium, a goggle display, a video camera and a portable telephone.

13. A light emitting device according to claim 9, wherein the first electrode and the second electrode comprise a material composing any one of an anode and a cathode;

and the first auxiliary electrode comprises a material composing the other of the anode and the cathode.

14. A light emitting device comprising:

a first TFT formed on an insulating surface;

a second TFT formed on the insulating surface;

a first insulating film formed over the first TFT and the second TFT;

a first pixel electrode formed on the first insulating film;

a second pixel electrode formed on the first insulating film;

a second insulating film formed covering a connection portion between the first pixel electrode and the first TFT, and a connection portion between the second pixel electrode and the second TFT;

an organic compound layer formed on the first pixel electrode and the second pixel electrode;

a first opposing electrode formed on the organic compound layer; and

a second opposing electrode formed on the organic compound layer,

wherein the first opposing electrode comprises a second auxiliary electrode and a third electrode,

wherein the second opposing electrode comprises the third electrode,

wherein the first pixel electrode and the second opposing electrode are any one of anodes and cathodes, and

wherein the second pixel electrode and the first opposing electrode are the other of the anodes and the cathodes.

15. A light emitting device according to claim 14, wherein the organic compound layer comprises a bipolar material having hole transporting characteristics and electron transporting characteristics.

16. A light emitting device according to claim 14, wherein the organic compound layer comprises a material having hole transporting characteristics and a material having electron transporting characteristics.

17. A light emitting device according to claim 14, wherein the light emitting device is selected from the group consisting of a display device, a digital still camera, a notebook personal computer, a mobile computer, a portable image playback device provided with a recording medium, a goggle display, a video camera and a portable telephone.

18. A method of manufacturing a light emitting device having a first light emitting element and a second light emitting element, the method comprising the steps of:

forming a first electrode and a second electrode on an insulating surface;

forming a first auxiliary electrode on the second electrode;

forming an organic compound layer over the first electrode, the second electrode, and the first auxiliary electrode;

forming a second auxiliary electrode over the organic compound layer and in a position overlapping with the first electrode; and

forming a third electrode over the organic compound layer and the second auxiliary electrode,

wherein the first light emitting element comprises;

a first pixel electrode comprising the first electrode;

the organic compound layer; and

a first opposing electrode comprising the second auxiliary electrode and the third electrode, and

wherein the second light emitting element comprises;

a second pixel electrode comprising the second electrode and the first auxiliary electrode;

the organic compound layer; and

a second opposing electrode comprising the third electrode.

19. A method of manufacturing a light emitting device according to claims 18, wherein the first pixel electrode and the second opposing electrode are any one of anodes and cathodes;

and the second pixel electrode and the first opposing electrode are the other of the anodes and the cathodes.

20. A method of manufacturing a light emitting device having a first light emitting element and a second light emitting element, the method comprising:

forming a first TFT and a second TFT on an insulating surface;

forming a first insulating layer over the first TFT and the second TFT;

forming a first electrode and a second electrode on the first insulating layer;

forming a first auxiliary electrode on the second electrode;

forming a second insulating layer covering a connection portion between the first electrode and the first TFT and a connection portion between the second electrode and the second TFT;

forming an organic compound layer over the first electrode, the second electrode, and the first auxiliary electrode;

forming a second auxiliary electrode over the organic compound layer and in a position overlapping with the first electrode; and

forming a third electrode on the organic compound layer and the second auxiliary electrode,

wherein the first light emitting element comprises;

a first pixel electrode comprising the first electrode;

the organic compound layer; and

a first opposing electrode comprising the second auxiliary electrode and the third electrode, and

wherein the second light emitting element comprises;

a second pixel electrode comprising the second electrode and the first auxiliary electrode;

the organic compound layer; and

a second opposing electrode comprising the third electrode.

21. A method of manufacturing a light emitting device according to claim 20, wherein the first TFT and the second TFT each have a source region and a drain region;

and the first electrode and the second electrode are electrically connected to any one of the source region and the drain region, in an opening portion formed in the interlayer insulating film.

22. A method of manufacturing a light emitting device according to claim 20, wherein the first pixel electrode and the second opposing electrode are any one of anodes and cathodes;

and the second pixel electrode and the first opposing electrode are the other of the anodes and the cathodes.