Organic light emitting device

• US 9,692,013 B2
• Filed: 11/26/2014
• Issued: 06/27/2017
• Est. Priority Date: 11/26/2013
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Hwang, Joo Hwan, Lee, Se Hee, Moon, Sang Kyoung
• Primary Examiner(s): Patel, Reema
• Assistant Examiner(s): GHEYAS, SYED I
• Application Number:
  US14/554,314
• Publication Number:
  US 20150144926A1
• Time in Patent Office: 944 Days
• CPC Class Codes: H10K 50/131 with spacer layers between the electroluminescent layers
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/16 Electron transporting layers
• 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 59/35 comprising red-green-blue [RGB] subpixels
• CPC Class Codes: H10K 59/80518 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair

Abstract

Disclosed is an organic light emitting device. The organic light emitting device includes a first emission unit configured to include a common blue emission material layer which is included in common in a plurality of pixels emitting lights having different wavelength ranges, a second emission unit configured to include a red emission material layer, a green emission material layer, and a blue emission material layer which respectively emit lights having different wavelength ranges, a charge generation layer disposed between the first emission unit and the second emission unit, a first electrode formed as a reflective electrode, and configured to supply an electric charge having a first polarity to the first emission unit and the second emission unit, and a second electrode formed as a semi-transmissive electrode, and configured to supply an electric charge having a second polarity to the first emission unit and the second emission unit.

Claims

1. An organic light emitting device including red, green, and blue pixels, the organic light emitting device comprising:

a first emission unit configured to include a first hole transport layer, a first electron transport layer on the first hole transport layer, and a common blue emission layer disposed between the first hole transport layer and the first electron transport layer, the common blue emission layer disposed in a plane common to the red, green and blue pixels;

a second emission unit configured to include a red emission material layer in the red pixel, a green emission material layer in the green pixel, and a blue emission material layer in the blue pixel, each of the red, green, and blue emission material layers being respectively configured to emit light having a different wavelength range;

a charge generation layer disposed between the first emission unit and the second emission unit;

a common first electrode including a reflective material disposed in another plane such that the common first electrode is common to the red, green and blue pixels, the common first electrode being configured to supply electric charges having a first polarity to the first emission unit and the second emission unit; and

a plurality of second electrodes each including a semi-transmissive electrode and respectively disposed in the red, green and blue pixels, the second electrodes configured to supply electric charges having a second polarity to the first emission unit and the second emission unit,

wherein respective micro cavities are defined in each of the red, green and blue pixels between the common first electrode and the respective second electrodes,

wherein the second emission unit further comprises a second hole transport layer and at least one of a red hole transport layer directly on the second hole transport layer in the red pixel and a green hole transport layer directly on the second hole transport layer in the green pixel, and

wherein the red hole transport layer is separate from the a green hole transport layer.

2. The organic light emitting device of claim 1, wherein the first emission unit further comprises a hole injection layer disposed on the common first electrode, wherein the first hole transport layer is disposed on the hole injection layer.

3. The organic light emitting device of claim 1, wherein an optical distance of a micro cavity is satisfied by using a thickness of the first hole transport layer.

4. The organic light emitting device of claim 1, wherein the second emission unit comprises:

a second electron transport layer disposed on the red emission material layer, the green emission material layer, and the blue emission material layer.

5. The organic light emitting device of claim 4, wherein an optical distance of each micro cavity includes a thickness of a respective one of the red emission material layer, the green emission material layer, and the blue emission material layer.

6. The organic light emitting device of claim 5, wherein the red emission material layer, the green emission material layer, and the blue emission material layer are disposed between the second hole transport layer and the second electron transport layer.

7. The organic light emitting device of claim 1, wherein the charge generation layer is included in the red pixel, the green pixel, and the blue pixel in common.

8. The organic light emitting device of claim 1, wherein the common blue emission layer is included in the red pixel, the green pixel, and the blue pixel in common.

9. The organic light emitting device of claim 1, wherein:

a thickness of the blue pixel is 1,500 Å

to 2,000 Å

,

a thickness of the green pixel is 2,000 Å

to 2,700 Å

, and

a thickness of the red pixel is 2,500 Å

to 3,100 Å

.

10. The organic light emitting device of claim 1, wherein,

the common blue emission layer and the red emission material layer have different thicknesses, and

the green emission material layer and the blue emission material layer have different thicknesses.

11. The organic light emitting device of claim 10, wherein the common blue emission layer has a thickness of 19 nm to 31 nm.

12. The organic light emitting device of claim 11, wherein the red emission material layer has a thickness of 93.6 nm to 115.6 nm.

13. The organic light emitting device of claim 12, further comprising a red hole transport layer disposed under the red emission material layer.

14. The organic light emitting device of claim 12, wherein the green emission material layer has a thickness of 41 nm to 53 nm.

15. The organic light emitting device of claim 14, further comprising a green hole transport layer disposed under the green emission material layer.

16. The organic light emitting device of claim 14, wherein the blue emission material layer has a thickness of 7 nm to 19 nm.

17. The organic light emitting device of claim 1, wherein the common blue emission layer includes one of a fluorescent material and a phosphor material, and wherein the red emission material layer, the green emission material layer, and the blue emission material layer each include materials of the other one of the fluorescent material and the phosphor material.

18. An organic light emitting device including red, green, and blue pixels each of which defines a respective micro cavity, the organic light emitting device comprising:

a first emission unit including a common blue emission layer which is disposed in common to the red, green and blue pixels;

a second emission unit including a red emission material layer in the red pixel, a green emission material layer in the green pixel, and a blue emission material layer in the blue pixel, each of the red, green, and blue emission material layers being respectively configured to emit light having a different wavelength range;

a charge generation layer disposed between the first emission unit and the second emission unit;

a first electrode including a reflective material and configured to supply electric charges having a first polarity to the first emission unit and the second emission unit; and

a plurality of second electrodes each including a semi-transmissive electrode and respectively disposed in the red, green and blue pixels, the second electrodes configured to supply electric charges having a second polarity to the first emission unit and the second emission unit,

wherein the first emission unit comprises;

a hole injection layer disposed on the first electrode;

a first hole transport layer disposed on the hole injection layer;

a first electron transport layer disposed on the common blue emission layer; and

the common blue emission layer disposed between the first hole transport layer

and the first electron transport layer;

wherein the second emission unit comprises;

a second hole transport layer on the charge generation layer;

the red emission material layer, the green emission material layer, and the blue emission material layer on the second hole transport layer; and

a second electron transport layer on the red emission material layer, the green emission material layer, and the blue emission material layer,

wherein the second emission unit further comprises at least one of a red hole transport layer directly on the second hole transport layer in the red pixel and a green hole transport layer directly on the second hole transport layer in the green pixel, and

wherein the red hole transport layer is separate from the a green hole transport layer.

19. The organic light emitting device of claim 18, wherein the common blue emission layer has a thickness of 19 nm to 31 nm, the red emission material layer has a thickness of 93.6 nm to 115.6 nm, the green emission material layer has a thickness of 41 nm to 53 nm, and the blue emission material layer has a thickness of 7 nm to 19 nm.