Light-emitting element and display device using same

• US 7,812,515 B2
• Filed: 09/07/2007
• Issued: 10/12/2010
• Est. Priority Date: 12/12/2002
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Adachi, Masaya, Nishimura, Etsuko, Murakami, Hajime, Tsuji, Kazutaka
• Primary Examiner(s): Williams; Joseph L
• Application Number:
  US11/852,153
• Publication Number:
  US 20080030132A1
• Time in Patent Office: 1,131 Days
• Field of Search: 313500-512, 257/40, 257/72
• US Class Current: 313/503
• CPC Class Codes: H05B 33/02 Details
• CPC Class Codes: H05B 33/04 Sealing arrangements , e.g. against humidity
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/321 Inverted OLED, i.e. having cathode between substrate and anode
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/82 Cathodes
• 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 50/841 Self-supporting sealing arrangements
• 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 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/122 : Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/123 : Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/124 : Insulating layers formed between TFT elements and OLED elements
• 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]
• CPC Class Codes: H10K 59/8051 : Anodes
• CPC Class Codes: H10K 59/80524 : Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/8722 : Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 59/8723 : Vertical spacers, e.g. arranged between the sealing arrangement and the OLED
• CPC Class Codes: H10K 59/878 : comprising reflective means
• CPC Class Codes: H10K 59/8791 : Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

A self light emitting display device having high level of the external coupling efficiency and high grade image presentation as no optical cross-talk or blur can be obtained by a new light-emitting element. The device is constructed as follows. A plurality of picture elements, each of which picture elements has an organic layer composing light emitting areas, a transparent electrode and a reflective electrodes, are formed on a substrate. Between the picture elements, a bank which has a tilted reflective surface is formed so that the light emitting area is surrounded by the bank wherein the transparent optical waveguide layer is formed as optically isolated for each of the picture elements.

Claims

1. A display device having a plurality of light-emitting elements that construct picture elements aligned on a substrate in a formation of a matrix wherein,

said light-emitting element comprising:

a light-emitting device having a flat surface at least a portion therein;

wherein the light-emitting device includes a light-emitting layer, an electrode functioning as an anode, and an electrode functioning as a cathode; and

a tilted reflective surface is made in a peripheral area surrounding said flat surface of said light-emitting device and has a tilt angle against said flat surface of said light-emitting device,

wherein, an optical waveguide layer is overlaid in an area surrounded by said tilted reflective surface on said light-emitting device, and wherein, said optical waveguide layer is optically isolated from each of said picture element; and

the light-emitting layers of the light-emitting devices comprise light-emitting layers that emit red-color light, light-emitting layers that emit green-color light and light-emitting layers that emit blue-color light.

2. The display device as defined in claim 1, wherein

a height of said optical waveguide layer from said flat surface of said light-emitting device is minimum at the center of area surrounded by said tilted reflective surface and becomes higher as closer to said tilted reflective surface.

4. The display device as defined in claim 1, wherein,

a height of said optical waveguide layer from said flat surface of said light-emitting device is minimum at the center of area surrounded by said tilted reflective surface and becomes higher as closer to said tilted reflective surface.

5. The display device as defined in claim 4, wherein a bank segregates said picture element into a plurality of areas and said tilted reflective surface is made on a surface of a slope of said bank.

6. The display device as defined in claim 5, wherein a bank that segregates said picture element into a plurality of areas is made on said reflective electrode.

7. The display device as defined in claim 1, wherein, a height of said optical waveguide layer from said flat surface of said light-emitting device is minimum at the center of area surrounded by said tilted reflective surface and higher against closer to said tilted reflective surface.

8. The display device as defined in claim 1, wherein a height of said optical waveguide layer from said flat surface of said light-emitting device is maximum at the center of area surrounded by said tilted reflective surface.

9. The display device as defined in claim 8, wherein said optical waveguide layer has a color changing medium layer consisting of fluorescent dye that converts blue light to green or red light.

10. The display device as defined in claim 1, wherein said light-emitting element is an organic light-emitting diode constructed with a reflective electrode that functions as an optical reflector, a light-emitting layer consisting of an organic layer and a transparent electrode stacked in order from said substrate.

11. The display device as defined in claim 10, wherein said tilted reflective surface consists of electrically conductive film that is electrically connected with said transparent electrode.

12. The display device as defined in claim 10, wherein said tilted reflective surface consists of electrically conductive film that is electrically connected with said reflective electrode or has a function of said reflective electrode.

13. The display device as defined in claim 10, wherein a sealing material that is transparent against visible light and has gas-barriering characteristics is set on a side of said light-emitting layer made on said substrate and wherein said substrate and said sealing material are adhesively bonded with a gap between said sealing material and said optical waveguide layer, said gap has substantially same refractive index as air.

14. The display device as defined in claim 10, wherein said Optical waveguide layer partly consists of a transparent inorganic layer that has gas-barriering characteristics.

15. The display device as defined in claim 10, wherein pigment is mixed and dispersed in said optical waveguide layer.

16. The display device as defined in claim 10, wherein refractive index of said optical waveguide layer is larger than that of air and lower than that of said transparent electrode.

3. A display device having a plurality of light-emitting elements that construct picture elements aligned on a substrate in a formation of a matrix wherein,

said light-emitting element comprising:

a light-emitting device having a flat surface at least a portion therein;

wherein

the light-emitting device includes a light-emitting layer, an electrode functioning as an anode, and an electrode functioning as a cathode; and

a tilted reflective surface is made in a peripheral area surrounding said flat surface of light-emitting device and has a tilt angle against said flat surface of said light-emitting device,

wherein,

an optical waveguide layer is overlaid in an area surrounded by said tilted reflective surface on said light-emitting device, and wherein, said optical waveguide layer is optically isolated from each of said picture element; and

every light-emitting layer of the light-emitting devices comprises a light-emitting layer that emits blue-color light; and

the optical waveguide layers of the light-emitting devices comprise color changing medium layers that emit red-color light when receiving the blue-color light emission, and color changing medium layers that emit green-color light when receiving the blue-color light emission.

17. A display device having a plurality of light-emitting elements that construct picture elements aligned on a substrate in a formation of a matrix wherein,

said light-emitting element comprising:

a light-emitting device having a flat surface at least a portion therein;

wherein the light-emitting device includes a light-emitting layer, an electrode functioning as an anode, and an electrode functioning as a cathode; and

a tilted reflective surface is made in a peripheral area surrounding said flat surface of light-emitting device and has a tilt angle against said flat surface of said light-emitting device,

wherein,

an optical waveguide layer is overlaid in an area surrounded by said tilted reflective surface on said light emitting device, and wherein, said optical waveguide layer is optically isolated from each of said picture element; and

every light-emitting layer of the light-emitting devices comprises a light-emitting layer that emits white-color light and

the optical waveguide layers of the light-emitting devices comprise optical waveguide layers including red-color pigment, optical waveguide layers including green-color pigment and optical waveguide layers including blue-color pigment.

18. The display device as defined in claim 17, wherein,

a height of said optical waveguide layer from said flat surface of said light-emitting device is minimum at the center of area surrounded by said tilted reflective surface and becomes higher as closer to said tilted reflective surface.