Organic electroluminescence element, organic electroluminescence display, and organic electroluminescence display apparatus

• US 8,796,914 B2
• Filed: 01/27/2011
• Issued: 08/05/2014
• Est. Priority Date: 04/07/2010
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Fujita, Yoshimasa, Ogata, Hidenori, Okamoto, Ken, Kobayashi, Yuhki, Yamada, Makoto, Kondoh, Katsumi
• Primary Examiner(s): Bowman, Mary Ellen
• Application Number:
  US13/637,631
• Publication Number:
  US 20130016296A1
• Time in Patent Office: 1,286 Days
• Field of Search: 428/690, 313/501, 313/504, 313/506, 313/507
• US Class Current: 313/501
• CPC Class Codes: H05B 33/02 Details
• CPC Class Codes: H05B 33/24 of metallic reflective layers H05B33/26 takes precedence
• CPC Class Codes: H05B 33/26 characterised by the composition or arrangement of the conductive material used as an electrode
• CPC Class Codes: H05B 33/28 of translucent electrodes
• CPC Class Codes: H10K 50/00 Organic light-emitting devices integrated devices or assemblies of multiple devices H10K59/00, H10K65/00; organic semiconductor lasers H01S5/36
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair

Abstract

The present invention includes: a reflective electrode (2); a translucent electrode (10); an organic EL layer (21) for emitting blue light, the organic EL layer being sandwiched between the reflective electrode and the translucent electrode; a red fluorescent substance layer (13) for converting the light from the organic EL layer (21) into red light; a green fluorescent substance layer (14) for converting the light from the organic EL layer (21) into green light; and a blue pixel including a light-distribution-characteristic adjusting layer (15) for adjusting a light distribution characteristic of the light from the organic EL layer (21), the present invention being structured such that the reflective electrode (2) and the translucent electrode (10) produce a microcavity effect.

Claims

1. An organic EL element comprising:

a reflective electrode and a translucent electrode having a structure producing a microcavity effect;

an organic EL layer for emitting blue light, the organic EL layer being sandwiched between the reflective electrode and the translucent electrode;

a red fluorescent substance layer for converting the light from the organic EL layer into light in a red range;

a green fluorescent substance layer for converting the light from the organic EL layer into light in a green range; and

a blue pixel allowing the light from the organic EL layer to transmit therethrough,

the red fluorescent substance layer and the green fluorescent substance layer including microparticles on a sub-micron order, and

the blue pixel being constituted by a light-distribution-characteristic adjusting layer for adjusting a light distribution characteristic of light from the organic EL layer.

2. The organic EL element according to claim 1,

wherein:

the light-distribution-characteristic adjusting layer adjusts (i) luminance of the light from the organic EL layer so as to cause the luminance of the light from the organic EL layer to be close to luminance of light emitted from the red fluorescent substance layer and to luminance of light emitted from the green fluorescent substance layer and (ii) color purity of the light from the organic EL layer so as to cause the color purity of the light from the organic EL layer to be close to color purity of the light emitted from the red fluorescent substance layer and to color purity of the light emitted from the green fluorescent substance layer.

3. The organic EL element according to claim 1,

wherein:

the light-distribution-characteristic adjusting layer adjusts the light distribution characteristic of the light from the organic EL layer so as to satisfy Formulae (1) and (2) below;

0.8L_60R/L_0R<

L_60B/L_0B<

1.2L_60R/L_0R 

 

(1)

0.8L_60G/L_0G<

L_60B/L_0B<

1.2L_60G/L_0G 

 

(2)

where;

L_0R represents a luminance, in a frontal direction, of light emitted from the red fluorescent substance layer;

L_60R represents a luminance, in a direction inclined at 60 degrees to the frontal direction, of the light emitted from the red fluorescent substance layer;

L_0G represents a luminance, in a frontal direction, of light emitted from the green fluorescent substance layer;

L_60G represents a luminance, in a direction inclined at 60 degrees to the frontal direction, of the light emitted from the green fluorescent substance layer;

L_0B represents a luminance, in a frontal direction, of light emitted from the light-distribution-characteristic adjusting layer; and

L_60B represents a luminance, in a direction inclined at 60 degrees to the frontal direction, of the light emitted from the light-distribution-characteristic adjusting layer.

4. The organic EL element according to claim 1,

wherein:

the light-distribution-characteristic adjusting layer adjusts the light distribution characteristic of the light from the organic EL layer so as to satisfy Formulae (3) through (6) below;

|x_60R−

x_0R|≧

|x_60B−

x_0B| 

 

(3)

|y_60R−

y_0R|≧

|y_60B−

y_0B| 

 

(4)

|x_60G−

x_0g|≧

|x_60B−

x_0B| 

 

(5)

|y_60G−

y_0G|≧

|y_60B−

y_0B| 

 

(6)

where;

(x_0R, y_0R) represents a color purity, in a frontal direction, of light emitted from the red fluorescent substance layer;

(x_60R, y_60R) represents a color purity, in a direction inclined at 60 degrees to the frontal direction, of the light emitted from the red fluorescent substance layer;

(x_0G, y_0G) represents a color purity, in a frontal direction, of light emitted from the green fluorescent substance layer;

(x_60G, y_60G) represents a color purity, in a direction inclined at 60 degrees to the frontal direction, of the light emitted from the green fluorescent substance layer;

(x_0B, y_0B) represents a color purity, in a frontal direction, of light emitted from the light-distribution-characteristic adjusting layer; and

(x_60B, y_60B) represents a color purity, in a direction inclined at 60 degrees to the frontal direction, of the light emitted from the light-distribution-characteristic adjusting layer.

5. The organic EL element according to claim 1,

wherein:

the light emitted by the organic EL layer has an emission intensity having a maximum value corresponding to a wavelength of not less than 400 nm and not greater than 480 nm.

6. The organic EL element according to claim 1,

wherein:

the light-distribution-characteristic adjusting layer includes light-scattering particles for scattering light; and

the organic EL element satisfies Formulae (7) and (8) below;

0.8d_50(B)<

d_50(R)<

1.2d_50(B) 

 

(7)

0.8d_50(B)<

d_50(G)<

1.2d_50(B) 

 

(8)

where;

d_50(R) represents an average particle diameter of a red fluorescent substance included in the red fluorescent substance layer;

d_50(G) represents an average particle diameter of a green fluorescent substance included in the green fluorescent substance layer; and

d_50(B) represents an average particle diameter of the light-scattering particles.

7. The organic EL element according to claim 6,

wherein:

the light-scattering particles include an inorganic material.

8. The organic EL element according to claim 6,

wherein:

the light-scattering particles have an average particle diameter of not less than 1 μ

m and not greater than 50 μ

m.

9. The organic EL element according to claim 1,

wherein:

at least one of a red fluorescent substance included in the red fluorescent substance layer and a green fluorescent substance included in the green fluorescent substance layer includes an inorganic material.

10. The organic EL element according to claim 1,

wherein:

at least one of a red fluorescent substance included in the red fluorescent substance layer and a green fluorescent substance included in the green fluorescent substance layer has an average particle diameter of not less than 0.5 μ

m and not greater than 50 μ

m.

11. The organic EL element according to claim 1,

wherein:

the translucent electrode includes silver.

12. The organic EL element according to claim 1,

wherein:

the translucent electrode has a film thickness of not less than 10 nm and not greater than 30 nm.

13. The organic EL element according to claim 1,

wherein:

the organic EL layer includes a phosphorescent material that emits phosphorescence in a blue range.

14. The organic EL element according to claim 1, further comprising:

a color filter on a surface of each of the red fluorescent substance layer, the green fluorescent substance layer, and the light-distribution-characteristic adjusting layer from which surface light is emitted.

15. The organic EL element according to claim 1, further comprising:

a polarizing plate on a side of the translucent electrode which side is opposite to a side on which the organic EL layer is provided.

16. The organic EL element according to claim 1, further comprising:

a liquid crystal layer for carrying out switching with respect to the red fluorescent substance layer, the green fluorescent substance layer, and the light-distribution-characteristic adjusting layer, the liquid crystal layer being provided between (i) the organic EL layer and (ii) the red fluorescent substance layer, the green fluorescent substance layer, and the light-distribution-characteristic adjusting layer.

17. An organic EL display comprising:

the organic EL element according to claim 1.

18. The organic EL display according to claim 17, further comprising:

an active element for carrying out active-matrix driving of the organic EL element.

19. The organic EL display according to claim 18,

wherein:

the active element is provided on a side of the reflective electrode which side is opposite to a side on which the organic EL layer is provided.

20. An organic EL display apparatus comprising:

the organic EL display according to claim 17.