LIGHT EMITTING ELEMENT

• US 20110198654A1
• Filed: 10/15/2009
• Published: 08/18/2011
• Est. Priority Date: 10/17/2008
• Status: Active Grant

• Current Assignee: UDC Ireland Limited (Universal Display Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Naya, Masayuki
• Granted Patent: US 9,887,388 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses

Abstract

A light emitting element includes an anode, a light transmitting cathode, and a light emitting layer sandwiched therebetween, formed on a surface of a substrate. Light emitted by the light emitting layer by voltage being applied between the electrodes is output from a surface toward the side of the light transmitting electrode. A light scattering layer for scattering evanescent light generated at the surface is provided on the surface of the light transmitting electrode. The light scattering layer has a first scattering portion having an uneven structure and a lower refractive index than the light emitting layer, and second scattering portions that fill at least the bottoms of recesses of the uneven structure and has a different refractive index from the first scattering portion. The distance between the bottoms of the recesses and the surface of the light transmitting electrode is a seepage depth of the evanescent light or less.

Claims

1-9. -9. (canceled)

10. A light emitting element, comprising:

a substrate;

a pair of electrodes formed on a surface of the substrate;

a light emitting layer sandwiched between the pair of electrodes;

at least one of the pair of electrodes being a light transmitting electrode, light being emitted from the light emitting layer by voltage being applied between the pair of electrodes, and the light being output from a surface toward the side of the light transmitting electrode; and

a light scattering layer provided on the surface of the light transmitting electrode, for scattering evanescent light which is generated at the surface;

the light scattering layer having a first scattering portion having an uneven structure and a refractive index lower than the refractive index of the light emitting layer, and second scattering portions that fill at least the bottoms of the recessed portions of the uneven structure of the first scattering portion and has a refractive index different from the refractive index of the first scattering portion; and

the distance between the bottoms of the recessed portions and the surface of the light transmitting electrode is less than or equal to a seepage depth of the evanescent light.

11. A light emitting element as defined in claim 10, wherein:

the second scattering portions are constituted by filling portions that fill the recessed portions, and a thin film layer which is formed on the filling portions and on protruding portions of the uneven structure.

12. A light emitting element as defined in claim 10, further comprising:

a protective layer provided on the surface of the light scattering layer toward the side of the light transmitting electrode.

13. A light emitting element as defined in claim 12, wherein:

the refractive index of the first scattering portion and the refractive index of the protective layer are approximately the same.

14. A light emitting element as defined in claim 10, wherein:

the second scattering portions are formed by metal.

15. A light emitting element as defined in claim 10, wherein:

the second scattering portions are formed by a dielectric having a higher refractive index than the refractive index of the first scattering portion.

16. A light emitting element as defined in claim 10, further comprising:

a semi transmissive/semi reflective metal film provided between the light transmitting electrode and the light scattering layer.

17. A light emitting element as defined in claim 10, wherein:

the light emitting layer is an organic electroluminescent element that includes an organic compound layer.

18. A light emitting element as defined in claim 10, wherein:

the light emitting layer is an inorganic electroluminescent element that includes an inorganic compound layer.