DISPLAY DEVICE

• US 20060175966A1
• Filed: 04/19/2006
• Published: 08/10/2006
• Est. Priority Date: 11/22/1999
• Status: Active Grant

• Current Assignee: Jiro Yamada, Takashi Hirano, Tatsuya Sasaoka
• Original Assignee: Jiro Yamada, Takashi Hirano, Tatsuya Sasaoka
• Inventors: Yamada, Jiro, Hirano, Takashi, Sasaoka, Tatsuya
• Granted Patent: US 7,218,049 B2
• Time in Patent Office: Days
• 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 display 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 an optical path length L of said cavity has a positive minimum value in a range that satisfies the equation;

(2L)/λ

+Φ

/(2π

)=m (m is an integer)

where 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 cavity and λ

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

wherein a spectrum peak shift produced by the difference of the view angles in the 0°

to 60°

range is less than 30 nm.

2. A display device of claim 1, further comprising

a color filter provided for transmitting light resonating in said cavity and extracted through said semi-transparent reflective layer.

3. A display device comprising:

a first electrode of a light reflecting material;

a transparent conductive layer provided on the first electrode;

a second electrode of a semi-transparent material; and

an organic layer including a light emitting layer interposed between the transparent conductive layer and the second electrode, the first electrode and the second electrode forming a resonant cavity,

wherein an optical path length L of said cavity has a positive minimum value in a range that satisfies the equation;

(2L)/λ

+Φ

/(2π

)=m (m is an integer)

where 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 cavity and λ

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

wherein a spectrum peak shift produced by the difference of the view angles in the 0°

to 60°

range is less than 30 nm.

4. A display device of claim 3, further comprising

a color filter provided for transmitting light resonating in said cavity and extracted through said second electrode.