Display device using an organic electroluminescence device having resonant cavity

• US 7,710,025 B2
• Filed: 03/28/2007
• Issued: 05/04/2010
• Est. Priority Date: 11/22/1999
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sasaoka, Tatsuya, Yamada, Jiro, Hirano, Takashi
• Primary Examiner(s): Roy; Sikha
• Application Number:
  US11/692,435
• Publication Number:
  US 20070228943A1
• Time in Patent Office: 1,133 Days
• Field of Search: None
• US Class Current: 313/506
• 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 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

In an organic EL device having a first electrode of a light reflective material, organic layer including an organic light emitting layer, semitransparent reflection layer, and second electrode of a transparent material that are stacked sequentially, and so configured that the organic layer functions as a cavity portion of a cavity structure, light that resonates in a certain spectral width (wavelength λ) is extracted by so configuring that optical path length L becomes minimum in a range satisfying (2L)/λ+Φ((2π)=m (m is an integer) where the phase shift produced in light generated in the organic light emitting layer when reflected by opposite ends of the cavity portion is Φ radians, L is optical path length of the cavity portion, and λ is the peak wavelength of the spectrum of part of light to be extracted.

Claims

1. A color display unit using an organic electroluminescence device comprising:

a semi-transparent reflective layer;

a reflective layer; and

an organic layer including a light emitting layer interposed between the semi-transparent reflective layer and the reflective layer, the semi-transparent reflective layer and the reflective layer forming a resonant cavity,

wherein,

said resonant cavity has an optical path length L determined such that a spectrum peak shift produced by a difference of viewing angles in the 0°

to 60°

range is less than 30 nm,

said optical path length L has a positive minimum value in a range that satisfies the equation (2L)/λ

+Φ

/(2π

)=m, where (a) m is an integer, (b) Φ

in radians is the sum of phase change amounts to reflection of the light emitted from the light emitting layer at both boundaries of the resonant cavity, and (c) λ

is the peak wavelength of the spectrum extracted from the display device, and

the color display unit is a color television apparatus.

2. A color display unit according to claim 1, further comprising

a color filter provided which transmits light resonating in said resonant cavity and extracted through said semi-transparent reflective layer.

3. A color display unit using an organic electroluminescence device comprising:

a first electrode of a light reflecting material;

a second electrode of a semi-transparent reflective layer;

a transplant transparent conductive layer provided on the second electrode; and

an organic layer including a light emitting layer interposed between the semi-transparent reflective layer and the reflective layer, the semi-transparent reflective layer and the reflective layer forming a resonant cavity,

wherein,

said resonant cavity has an optical path length L determined so that a spectrum peak shift produced by a different of viewing angles in the 0°

to the 60°

range is less than 30 nm,

said optical path length L has a positive minimum value in a range that satisfies the equation (2L)/λ

+Φ

/(2π

)=m, where (a) m is an integer, (b) Φ

radians is the sum of phase change amounts to reflection of the light emitted from the light emitting layer at both boundaries of the resonant cavity, and (c) λ

is the peak wavelength of the spectrum extracted from the device, and

the color display unit is a color television apparatus.

4. A color display unit according to claim 3, further comprising a color filter provided which transmits light resonating in said resonant cavity and extracted through said semi-transparent reflective layer.