Organic light emitting device, display unit including the same, and illuminating device including the same

• US 8,405,098 B2
• Filed: 05/17/2010
• Issued: 03/26/2013
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Matsunami, Shigeyuki, Fukuda, Toshihiro, Yamada, Jiro
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): KUSUMAKAR, KAREN M
• Application Number:
  US12/781,089
• Publication Number:
  US 20100314636A1
• Time in Patent Office: 1,044 Days
• Field of Search: 257/88, 257/89, 438/25, 438/31
• US Class Current: 257/88
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

An organic light emitting device includes a first electrode and second electrode on a substrate. Light emitting units are positioned between the first and second electrodes. A first light emitting unit includes a first light emitting layer, and a second light emitting unit includes a second light emitting layer. The first electrode reflects light from at least one of the light emitting units to generate an interference pattern with light emitted from the first light emitting layer. The interference pattern has a plurality of interference positions such that a first interference position is located within the first light emitting layer, and a second interference position is located within the second light emitting layer.

Claims

1. An organic light emitting device, comprising:

a first electrode on a substrate;

a second electrode on the substrate; and

a plurality of light emitting units between the first electrode and the second electrode, the plurality of light emitting units including a first light emitting unit that includes a first light emitting layer, and a second light emitting unit that includes a second light emitting layer,

wherein,

the first electrode reflects light from at least one of the plurality of light emitting units to generate an interference pattern with light emitted from the first light emitting layer,

the interference pattern includes a plurality of interference positions, the plurality of interference positions being located at peak positions of the resulting interference between the reflected light and the light emitted from the first light emitting layer, and

the plurality of light emitting units are positioned such that a first interference position is located within the first light emitting layer, and a second interference position is located within the second light emitting layer.

2. The device of claim 1, wherein the first interference position is located closer to the first electrode than the second interference position.

3. The device of claim 1, wherein the first light emitting unit is positioned closer to the first electrode than the second light emitting unit.

4. The device of claim 1, wherein,

the first light emitting layer is a blue light emitting layer, and

the second light emitting layer is a different color from the first light emitting layer.

5. The device of claim 4, wherein,

the second light emitting layer is selected from a group consisting of a red light emitting layer and a green light emitting layer.

6. The device of claim 1, wherein the second light emitting layer is a yellow light emitting layer such that white light is obtained by a color mixture of the light from the first light emitting layer and the yellow light emitting layer.

7. The device of claim 1, further comprising:

an electric charge layer positioned between the first light emitting unit and the second light emitting unit.

8. The device of claim 1, wherein,

the first light emitting unit further includes an electron transport layer,

the second light emitting unit further includes an electron hole transport layer, and

a thickness of the electron transport layer is larger than a thickness of the electron hole transport layer.

9. An organic light emitting device, comprising:

a stack that includes an anode, a first light emitting layer, a second light emitting layer, and a cathode, the stack being configured to emit white light and generate interference between light emitted from the first light emitting layer and light reflected from the anode,

wherein,

the resulting interference has an interference pattern that includes a first interference peak position and a second interference peak position,

the first interference peak position is located within the first light emitting layer, and

the second interference peak position is located within the second light emitting layer, the second light emitting layer being selected from a group consisting of a red light emitting layer, a green light emitting layer, and a yellow light emitting layer.

10. The device of claim 9, wherein the first light emitting layer is a blue light emitting layer.

11. The device of claim 9, wherein the anode is a laminated structure that includes a metal film and a transparent electrode film.

12. The device of claim 9, wherein color filters are provided on a side of the cathode that faces away from the anode.

13. The device of claim 9, wherein an optical distance between the first interference peak position and the anode is less than an optical distance between the second interference peak position and the anode.

14. The device of claim 9, wherein an optical distance (L₁) between the first interference position and the anode is set such that L₁=(m₁−

Φ

/2π

)·

λ

₁/2,

wherein,

m₁ represents zero or an integer,

Φ

represents a phase shift that is generated when light generated in the first light emitting layer is reflected by the first electrode, and

λ

₁ represents a peak wavelength of spectrum when light generated in the first light emitting layer is irradiated from a side facing the cathode.

15. The device of claim 14, wherein an optical distance (L₂) between the second interference position and the anode is set such that L₂=(m₂−

Φ

/2π

)λ

₂/2

wherein,

m₂ represents an integer such that m₂>

m₁,

Φ

represents a phase shift that is generated when light generated in the first light emitting layer is reflected by the first electrode, and

λ

₂ represents a peak wavelength of spectrum when light generated in the first light emitting layer is irradiated from a side facing the cathode.

16. The device of claim 9, further comprising:

an electric charge layer positioned in the stack, the electric charge layer being between the first light emitting layer and the second light emitting layer.

17. A method of fabricating an organic light emitting device that emits white light, comprising:

forming an anode of a laminate structure having a metal film and a transparent film;

forming a plurality of light emitting units on one side of the anode, the plurality of light emitting units including (a) a first light emitting unit having a first light emitting layer and (b) a second light emitting unit having a second light emitting layer, wherein the first light emitting unit and the second light emitting unit are separated by an intervening electric charge layer; and

forming a cathode such that the plurality of light emitting units are between the anode and the cathode in a stack structure;

wherein,

an interference pattern is generated between light emitted from the first light emitting layer and light reflected from the anode, the interference pattern includes a first interference peak position and a second interference peak position,

a distance between the anode and the first light emitting layer is formed such that a first interference peak position of the interference pattern is located within the first light emitting layer, and

a distance between the anode and the second light emitting layer is formed such that the second interference peak position of the interference pattern is located within the second light emitting layer.

18. The method of claim 17, wherein,

the first light emitting layer is a blue light emitting layer, and

the second light emitting layer emits a color of light that is different from the first light emitting layer.

19. A display unit, comprising

a display region, and

a plurality of organic light emitting devices within the display region,

wherein each organic light emitting device, comprises:

an anode;

a cathode; and

a plurality of light emitting units between the anode and the cathode, the plurality of light emitting units including a first light emitting unit that includes a first light emitting layer, and a second light emitting unit that includes a second light emitting layer,

wherein,

the anode reflects light from at least one of the plurality of light emitting units to generate an interference pattern with light emitted from the first light emitting layer, the interference pattern including a plurality of interference peaks, and

the plurality of light emitting units being positioned such that the first light emitting layer intercepts a first interference peak, and the second light emitting layer intercepts a second interference peak.

20. An illuminating device, comprising

a lighting section, and

an organic light emitting device that is enabled to emit light from within the lighting section, the organic light emitting device comprises:

an anode;

a cathode; and

a plurality of light emitting units between the anode and the cathode, the plurality of light emitting units including a first light emitting unit that includes a first light emitting layer, and a second light emitting unit that includes a second light emitting layer,

wherein,

the anode reflects light from at least one of the plurality of light emitting units to generate an interference pattern with light emitted from the first light emitting layer, the interference pattern including a plurality of interference peaks, and

the plurality of light emitting units being positioned such that the first light emitting layer intercepts a first interference peak, and the second light emitting layer intercepts a second interference peak.