Light emitting device driving by alternating current in which light emission is always obtained

• US 6,876,007 B2
• Filed: 11/06/2002
• Issued: 04/05/2005
• Est. Priority Date: 11/22/2001
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Seo, Satoshi, Yamazaki, Shunpei
• Primary Examiner(s): Lewis, Monica
• Application Number:
  US10/288,547
• Publication Number:
  US 20030094612A1
• Time in Patent Office: 881 Days
• Field of Search: 257/40, 257/79, 257/88, 257/59, 257/918, 313/503, 313/504, 313/506
• US Class Current: 257/88
• 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 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/17 Passive-matrix OLED displays
• CPC Class Codes: H10K 59/805 Electrodes
• CPC Class Codes: H10K 59/80516 combined with auxiliary electrodes, e.g. ITO layer combined with metal lines
• CPC Class Codes: H10K 59/80522 combined with auxiliary 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 when electrodes comprising the first pixel electrode and the second opposing electrode are anodes, the electrodes comprising the second pixel electrode and the first opposing electrode are cathodes, and

wherein when electrodes comprising the first pixel electrode and the second opposing electrode are cathodes, the electrodes comprising the second pixel electrode and the first opposing electrode are anodes.

2. The light emitting device according to claim 1, wherein the organic compound layer has bipolar characteristics.

3. The 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. The light emitting device according to claim 1, wherein the light emitting device is one 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 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 comprises a first electrode,

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

wherein when electrodes comprising the first pixel electrode and the second opposing electrode are anodes, the electrodes comprising the second pixel electrode and the first opposing electrode are cathodes, and

wherein when electrodes comprising the first pixel electrode and the second opposing electrode are cathodes, the electrodes comprising the second pixel electrode and the first opposing electrode are anodes.

6. The light emitting device according to claim 5, wherein the organic compound layer has bipolar characteristics.

7. The 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. The light emitting device according to claim 5, wherein the light emitting device is one 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. The light emitting device according to claim 5, wherein electrodes comprising the first electrode and the second electrode comprise a material composing an anode or a cathode;

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

10. 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 opposing electrode comprises an auxiliary electrode and a first electrode,

wherein the second opposing electrode comprises a second electrode,

wherein when electrodes comprising the first pixel electrode and the second opposing electrode are anodes, the electrodes comprising the second pixel electrode and the first opposing electrode are cathodes, and

wherein when electrodes comprising the first pixel electrode and the second opposing electrode are cathodes, the electrodes comprising the second pixel electrode and the first opposing electrode are anodes.

11. The light emitting device according to claim 10, wherein the organic compound layer has bipolar characteristics.

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

13. The light emitting device according to claim 10, wherein the light emitting device is one 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.

14. The light emitting device according to claim 10, wherein electrodes comprising the first electrode and the second electrode comprise a material composing an anode or a cathode;

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