ORGANIC LIGHT-EMITTING ELEMENT

• US 20170033317A1
• Filed: 05/08/2015
• Published: 02/02/2017
• Est. Priority Date: 05/12/2014
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kajimoto, Norifumi
• Granted Patent: US 10,637,004 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G03G 15/043 with means for controlling illumination or exposure G03G15/041 takes precedence
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: H10K 2101/00 Properties of the organic materials covered by group H10K85/00
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/13 comprising stacked EL layers within one EL unit
• CPC Class Codes: H10K 50/131 with spacer layers between the electroluminescent layers
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 50/87 Arrangements for heating or cooling
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/18 Tiled displays
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

Provided is an organic light-emitting element for emitting white light in which an optical distance L₁ between a first emission layer (52) and a reflective electrode (80) satisfies Expression (a), and an optical distance L₂ between a second emission layer (72) and the reflective electrode (80) satisfies Expression (b):

(λ₁/8)×(3−(2φ₁/π))<L₁<(λ₁/8)×(5−(2φ₁/π))  (a); and

(λ₂/8)×(−(2φ₂/π)−1)<L₂<(λ₂/8)×(−(2φ₂/π)+1)  (b), and

in which a refractive index of a first charge transport layer (51) formed between a light extraction electrode (4) and the first emission layer (52) at the wavelength λ₁ is 1.70 or less.

Claims

1. An organic light-emitting element for emitting white light comprising, in the stated order:

a first electrode;

a first emission layer;

a second emission layer; and

a second electrode,

the first electrode being a light extraction electrode,

the second electrode being a reflective electrode,

the first emission layer being an emission layer for emitting blue light,

wherein an optical distance L₁ between the first emission layer and the second electrode satisfies Expression (a), and an optical distance L₂ between the second emission layer and the second electrode satisfies Expression (b);

(λ

₁/8)×

(3−

(2φ

₁/π

))<

L₁<

(λ

₁/8)×

(5−

(2φ

₁/90 )) 

 

(a); and

(λ

₂/8)×

(−

(2φ

₂/π

)−

1)<

L₂<

(λ

₂/8)×

(−

(2φ

₂/π

)+1) 

 

(b),

where λ

₁ is a maximum peak wavelength of light emitted from a light-emitting material included in the first emission layer, λ

₂ is a maximum peak wavelength of light emitted from a light-emitting material included in the second emission layer, φ

₁ is a phase shift upon reflection of the light having the maximum peak wavelength λ

₁ at the second electrode, and φ

₂ is a phase shift upon reflection of the light having the maximum peak wavelength λ

₂ at the second electrode, and

wherein the organic light-emitting element further comprises a first organic compound layer formed between the first electrode and the first emission layer, and a refractive index of the first organic compound layer at the wavelength λ

₁ is 1.70 or less.

2. The organic light-emitting element according to claim 1, further comprising a non-interfering layer formed on a light extraction side of the first electrode,

wherein a refractive index of the non-interfering layer at the wavelength k_i is 1.65 or less.

3. The organic light-emitting element according to claim 1, wherein a refractive index of the first electrode at the wavelength λ

₁ is 2.2 or less.

4. The organic light-emitting element according to claim 1,

wherein the second emission layer comprises two kinds of light-emitting materials, and

wherein the wavelength λ

₂ comprises one of a maximum peak wavelength of light that is emitted from any one of the two kinds of light-emitting materials and a maximum peak wavelength of light formed by mixing light beams that are emitted from the two kinds of light-emitting materials.

5. The organic light-emitting element according to claim 4, wherein the two kinds of light-emitting materials of the second emission layer comprise a light-emitting material for emitting red light and a light-emitting material for emitting green light.

6. The organic light-emitting element according to claim 1, further comprising a second organic compound layer formed between the second electrode and the second emission layer,

wherein a refractive index of the second organic compound layer at the wavelength λ

₁ is 1.70 or less.

7. The organic light-emitting element according to claim 1, further comprising a third organic compound layer formed between the first emission layer and the second emission layer,

wherein a refractive index of the third organic compound layer at the wavelength λ

₁ is 1.70 or less.

8. The organic light-emitting element according to claim 1, wherein a refractive index of the first emission layer at the wavelength λ

₁ is 1.8 to 2.1.

9. The organic light-emitting element according to claim 1, further comprising a charge generation layer formed between the first emission layer and the second emission layer.

10. A display device comprising a plurality of light emission points, the plurality of light emission points comprising the organic light-emitting element according to claim 1.

11. The display device according to claim 10, further comprising an active element connected to the organic light-emitting element,

wherein the active element comprises an oxide semiconductor formed in an active layer thereof.

12. The display device according to claim 10, further comprising a color filter formed on a light extraction side.

13. An image information processing apparatus comprising:

an input unit for inputting image information; and

a display unit for displaying the image information, the display unit comprising the display device according to claim 10.

14. A lighting apparatus comprising:

the organic light-emitting element according to claim 1; and

a circuit for supplying a drive current to the organic light-emitting element.

15. A lighting apparatus comprising:

the organic light-emitting element according to claim 1; and

a heat dissipation member.

16. The lighting apparatus according to claim 14, further comprising an active element connected to the organic light-emitting element,

wherein the active element comprises an oxide semiconductor formed in an active layer thereof.

17. An electrophotographic image forming apparatus comprising:

a photosensitive member;

a charging unit for charging the photosensitive member;

an exposure unit for exposing the photosensitive member; and

a developing unit for developing an electrostatic latent image formed on the photosensitive member,

the exposure unit comprising the organic light-emitting element according to claim 1,

the organic light-emitting element comprising a plurality of organic light-emitting elements disposed in a line along a long axis direction of the photosensitive member.

18. The electrophotographic image forming apparatus according to claim 17, further comprising an active element connected to the organic light-emitting element,

wherein the active element comprises an oxide semiconductor formed in an active layer thereof.

19. An exposure device to be provided in an electrophotographic image forming apparatus comprising:

a photosensitive member;

a charging unit for charging the photosensitive member; and

a developing unit for developing an electrostatic latent image formed on the photosensitive member,

the exposure device being configured to expose the photosensitive member,

the exposure device comprising the organic light-emitting element according to claim 1,

the organic light-emitting element comprising a plurality of organic light-emitting elements disposed in a line along a long axis direction of the photosensitive member.

20. The exposure device according to claim 19, further comprising an active element connected to the organic light-emitting element,

wherein the active element comprises an oxide semiconductor formed in an active layer thereof.