Light-emitting element and display device

• US 9,349,775 B2
• Filed: 08/06/2015
• Issued: 05/24/2016
• Est. Priority Date: 05/20/2004
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ikeda, Hisao, Ohara, Hiroki, Hosoba, Makoto, Sakata, Junichiro, Ito, Shunichi
• Primary Examiner(s): PRENTY, MARK V
• Application Number:
  US14/819,550
• Publication Number:
  US 20160035796A1
• Time in Patent Office: 292 Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/136222 Colour filters incorporated in the active matrix substrate
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: H10K 2102/00 Constructional details relating to the organic devices covered by this subclass
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 2102/311 Flexible OLED
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/84 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/8428 Vertical spacers, e.g. arranged between the sealing arrangement and the OLED
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 50/865 comprising light absorbing layers, e.g. light-blocking layers
• CPC Class Codes: H10K 59/122 : Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/126 : Shielding, e.g. light-blocking means over the TFTs
• CPC Class Codes: H10K 59/35 : comprising red-green-blue [RGB] subpixels
• CPC Class Codes: H10K 59/38 : comprising colour filters or colour changing media [CCM]

Abstract

There has been a problem that difference in refractive index between an opposite substrate or a moisture barrier layer provided thereover, and air is maintained large, and light extraction efficiency is low. Further, there has been a problem that peeling or cracking due to the moisture barrier layer is easily generated, which leads to deteriorate the reliability and lifetime of a light-emitting element. A light-emitting element comprises a pixel electrode, an electroluminescent layer, a transparent electrode, a passivation film, a stress relieving layer, and a low refractive index layer, all of which are stacked sequentially. The stress relieving layer serves to prevent peeling of the passivation film. The low refractive index layer serves to reduce reflectivity of light generated in the electroluminescent layer in emitting to air. Therefore, a light-emitting element with high reliability and long lifetime and a display device using the light-emitting element can be provided.

Claims

1. A light-emitting device comprising:

a first electrode over a first substrate;

a light-emitting layer over the first electrode;

a second electrode over the light-emitting layer;

a first layer over the second electrode, the first layer comprising at least one of an organic material and an inorganic material;

a second layer over the first layer, the second layer comprising carbon;

a third layer over the second layer, the third layer comprising aluminum;

a fourth layer over the third layer, the fourth layer comprising polymer;

a second substrate over the fourth layer,

wherein the second electrode is capable of transmitting light emitted from the light-emitting layer.

2. The light-emitting device according to claim 1, wherein the light-emitting layer comprises a luminescent center pigment.

3. The light-emitting device according to claim 1, wherein the light-emitting layer emits white light.

4. The light-emitting device according to claim 1, further comprising a color filter between the fourth layer and the second substrate.

5. The light-emitting device according to claim 1, wherein the fourth layer is a liquid layer or a solid layer.

6. The light-emitting device according to claim 1, wherein a refractive index of the fourth layer is larger than a refractive index of air or nitrogen gas.

7. The light-emitting device according to claim 1, wherein a refractive index of the fourth layer is approximately 1.2 to 1.6.

8. The light-emitting device according to claim 1, wherein a refractive index of the second layer is larger than a refractive index of the first layer.

9. An electric appliance comprising a light-emitting device according to claim 1.

10. A lighting device comprising a light-emitting device according to claim 1.

11. A light-emitting device comprising:

a first electrode over a first flexible substrate;

a light-emitting layer over the first electrode;

a second electrode over the light-emitting layer;

a first layer over the second electrode, the first layer comprising at least one of an organic material and an inorganic material;

a second layer over the first layer, the second layer comprising carbon;

a third layer over the second layer, the third layer comprising aluminum;

a fourth layer over the third layer, the fourth layer comprising polymer;

a second flexible substrate over the fourth layer,

wherein the second electrode is capable of transmitting light emitted from the light-emitting layer.

12. The light-emitting device according to claim 11, wherein the light-emitting layer comprises a luminescent center pigment.

13. The light-emitting device according to claim 11, wherein the light-emitting layer emits white light.

14. The light-emitting device according to claim 11, further comprising a color filter between the fourth layer and the second flexible substrate.

15. The light-emitting device according to claim 11, wherein the fourth layer is a liquid layer or a solid layer.

16. The light-emitting device according to claim 11, wherein a refractive index of the fourth layer is larger than a refractive index of air or nitrogen gas.

17. The light-emitting device according to claim 11, wherein a refractive index of the fourth layer is approximately 1.2 to 1.6.

18. The light-emitting device according to claim 11, wherein a refractive index of the second layer is larger than a refractive index of the first layer.

19. An electric appliance comprising a light-emitting device according to claim 11.

20. A lighting device comprising a light-emitting device according to claim 11.