ELECTROLUMINESCENT DEVICE

• US 20070069996A1
• Filed: 09/25/2006
• Published: 03/29/2007
• Est. Priority Date: 09/26/2005
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: Kyocera Display Institute Co. Ltd. (Kyocera Corporation)
• Inventors: Abe, Shinichi, Kuba, Yutaka
• Granted Patent: US 7,755,577 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• 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 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair

Abstract

An electroluminescent device includes a first optical output part having a light-emitting layer emitting a light ray of a first color, a second optical output part having a light-emitting layer emitting a light ray of a second color, and a third optical output part having a light-emitting layer emitting a light ray of a third color, the colors being different from one another. Each of the optical output parts also has a resonator structure that resonates the light ray emitted from the light-emitting layer. In each optical output part, a resonant peak wavelength indicating a peak value of a transmission spectrum of light transmitted through the resonator structure in a direction perpendicular to a main surface of the light-emitting layer is on a longer or shorter wavelength side of an emission peak wavelength indicating a peak value of an emission spectrum of the light ray emitted by the light-emitting layer.

Claims

1. An electroluminescent device comprising:

a first optical output part including a light-emitting layer that emits a light ray of a first color and a resonator structure that resonates the light ray of the first color emitted from the light-emitting layer;

a second optical output part including a light-emitting layer that emits a light ray of a second color and a resonator structure that resonates the light ray of the second color emitted from the light-emitting layer; and

a third optical output part including a light-emitting layer that emits a light ray of a third color and a resonator structure that resonates the light ray of the third color emitted from the light-emitting layer,

wherein the first, second, and third colors are different from one another, and

wherein, in each of the first to third optical output parts, when a peak value of a transmission spectrum of light transmitted through the resonator structure in a direction perpendicular to a main surface of the light-emitting layer is defined as a resonant peak wavelength, the resonant peak wavelength is on a longer wavelength side of an emission peak wavelength indicating a peak value of an emission spectrum of the light ray emitted by the light-emitting layer.

2. The electroluminescent device according to claim 1, wherein the resonant peak wavelength of each of the first to third optical output parts is within a visible light range.

3. The electroluminescent device according to claim 1, wherein the first, second, and third colors are red, green, and blue colors, respectively.

4. The electroluminescent device according to claim 3, wherein when differences between the emission peak wavelengths of the light rays emitted by the first to third optical output parts and the corresponding resonant peak wavelengths are represented as Δ

λ

r, Δ

λ

g, Δ

λ

b, the following conditions are satisfied;

0.5≦

Δ

λ

g/Δ

λ

r≦

2, and

0.5≦

Δ

λ

b/Δ

λ

g≦

2.

5. The electroluminescent device according to claim 1, wherein the resonator structure in each of the first to third optical output parts includes one or more layers interposed between a pair of electrodes that are disposed on opposite sides of the corresponding light-emitting layer in a thickness direction thereof.

6. The electroluminescent device according to claim 1, further comprising a substrate on which the first to third optical output parts are disposed;

and a sealing film which covers the first to third optical output parts and transmits the light rays emitted from the first to third optical output parts,

wherein the sealing film is included in the resonator structures of the optical output parts.

7. The electroluminescent device according to claim 1, further comprising a transparent substrate on which the first to third optical output parts are disposed, the transparent substrate transmitting the light rays emitted from the first to third optical output parts,

wherein the transparent substrate is included in the resonator structures of the optical output parts.

8. The electroluminescent device according to claim 1, wherein the resonator structures in the first to third optical output parts include all layers and components through which the light rays emitted from the first to third optical output parts are transmitted before being output outward.

9. The electroluminescent device according to claim 1, wherein absolute values of differences between the emission peak wavelengths of the light rays emitted from the first to third optical output parts and the corresponding resonant peak wavelengths are set to larger values for the optical output parts having the resonator structures with larger thicknesses.

10. An electroluminescent device comprising:

a first optical output part including a light-emitting layer that emits a light ray of a first color and a resonator structure that resonates the light ray of the first color emitted from the light-emitting layer;

a second optical output part including a light-emitting layer that emits a light ray of a second color and a resonator structure that resonates the light ray of the second color emitted from the light-emitting layer; and

a third optical output part including a light-emitting layer that emits a light ray of a third color and a resonator structure that resonates the light ray of the third color emitted from the light-emitting layer,

wherein the first, second, and third colors are different from one another, and

wherein, in each of the first to third optical output parts, when a peak value of a transmission spectrum of light transmitted through the resonator structure in a direction perpendicular to a main surface of the light-emitting layer is defined as a resonant peak wavelength, the resonant peak wavelength is on a shorter wavelength side of an emission peak wavelength indicating a peak value of an emission spectrum of the light ray emitted by the light-emitting layer.

11. The electroluminescent device according to claim 10, wherein the resonant peak wavelength of each of the first to third optical output parts is within a visible light range.

12. The electroluminescent device according to claim 10, wherein the first, second, and third colors are red, green, and blue colors, respectively.

13. The electroluminescent device according to claim 12, wherein when differences between the emission peak wavelengths of the light rays emitted by the first to third optical output parts and the corresponding resonant peak wavelengths are represented as Δ

λ

r, Δ

λ

g, Δ

λ

b, the following conditions are satisfied;

0.5≦

Δ

λ

g/Δ

λ

r≦

2, and

0.5≦

Δ

λ

b/Δ

λ

g≦

2.

14. The electroluminescent device according to claim 10, wherein the resonator structure in each of the first to third optical output parts includes one or more layers interposed between a pair of electrodes that are disposed on opposite sides of the corresponding light-emitting layer in a thickness direction thereof.

15. The electroluminescent device according to claim 10, further comprising a substrate on which the first to third optical output parts are disposed;

and a sealing film which covers the first to third optical output parts and transmits the light rays emitted from the first to third optical output parts,

wherein the sealing film is included in the resonator structures of the optical output parts.

16. The electroluminescent device according to claim 10, further comprising a transparent substrate on which the first to third optical output parts are disposed, the transparent substrate transmitting the light rays emitted from the first to third optical output parts,

wherein the transparent substrate is included in the resonator structures of the optical output parts.

17. The electroluminescent device according to claim 10, wherein the resonator structures in the first to third optical output parts include all layers and components through which the light rays emitted from the first to third optical output parts is transmitted before being output outward.

18. The electroluminescent device according to claim 10, wherein absolute values of differences between the emission peak wavelengths of the light rays emitted from the first to third optical output parts and the corresponding resonant peak wavelengths are set to larger values for the optical output parts having the resonator structures with larger thicknesses.