Light emitting device with an incorporated optical wavelight layer

• US 7,030,556 B2
• Filed: 09/02/2003
• Issued: 04/18/2006
• 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): Santiago, Mariceli
• Application Number:
  US10/653,623
• Publication Number:
  US 20040113550A1
• Time in Patent Office: 959 Days
• Field of Search: 313/498, 313/506, 313/110, 313/111, 257/98
• US Class Current: 313/506
• 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]

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 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 by said tilted reflective surface.

2. A light-emitting element as defined in claim 1, wherein cross sectional width of said optical waveguide layer is wider against distance farther from said flat surface of said light-emitting layer.

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.

4. A display device as defined in claim 3, wherein, said tilted reflective surface is made on the surface of a slope formed by a bank that is made on said substrate, and wherein, cross sectional width of said bank is narrower against distance farther from surface of said substrate.

5. A 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. A display device as defined in claim 5,

wherein one of the electrodes is a reflective electrode, and

wherein a bank that segregates said picture element into a plurality of areas is made on said reflective electrode.

7. A display device as defined in claim 3, wherein, said optical waveguide layer has a cross sectional formation as a cross sectional width of said optical waveguide layer is wider against distance farther from surface of said substrate, and wherein, a height of said tilted reflective surface from said flat surface of said light-emitting layer is larger than the maximum height of said optical waveguide layer.

8. A display device as defined in claim 3, wherein said optical waveguide layer is optically isolated from each picture element.

9. A display device as defined in claim 3, 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.

10. A display device as defined in claim 9, wherein

said tilted reflective surface consists of electrically conductive film that is electrically connected with said transparent electrode.

11. A display device as defined in claim 9, 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.

12. A display device as defined in claim 9, wherein said optical waveguide layer partly consists of a transparent inorganic layer that has gas-barriering characteristics.

13. A display device as defined in claim 9, wherein pigment is mixed and dispersed in said optical waveguide layer.

14. 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 layer having a flat surface at least a portion therein; and

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

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

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

15. 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 layer having a flat surface at least a portion therein; and

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

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

wherein a height of said optical waveguide layer from said flat surface of said light-emitting layer is maximum at the center of area surrounded by said tilted reflective surface.

16. A display device as defined in claim 15, wherein said optical waveguide layer has a color changing medium layer consisting of fluorescent dye that converts blue light to green or red light.

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 layer having a flat surface at least a portion therein;

a transparent electrode; and

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

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

wherein refractive index of said optical waveguide layer is larger than that of air and lower than that said transparent electrode.

18. 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 layer having a flat surface at least a portion therein; and

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

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

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, and

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.