Organic electroluminescence element and lighting device using same

Patent metadata

Field	Value
Publication number	US-9577206-B2
Application number	US-201414772548-A
Country	US
Kind code	B2
Filing date	Mar 3, 2014
Priority date	Mar 13, 2013
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

The present disclosure relates to an organic electroluminescence element including: a substrate having a light transmissive property; a light diffusion layer; a light transmissive electrode; a light reflective electrode; and multiple light emitting layers spaced from each other. With regard to the m-th light emitting layer being the m-th closest light emitting layer to the light reflective electrode, relations defined by following expressions (2) and (3) are satisfied. In the following expressions, λ m represents the weighted average emission wavelength, Ø(λ m ) represents the phase shift, n m (λ m ) represents the average refractive index of a medium filling a space between the light reflective electrode and the m-th light emitting layer, and d m represents the distance from the light reflective electrode to the m-th light emitting layer. l is an integer equal to or more than 0.

⁢

[

FORMULA
⁢

⁢
1

]

ϕ
⁡

(

λ
m

)

×

λ
m

4
⁢

⁢
π

+

l
+
0.1

2

⁢

λ
m

≤

n
m

⁡

(

λ
m

)

×

d
m

≤

ϕ
⁡

(

λ
m

)

×

λ
m

4
⁢

⁢
π

+

l
+
0.6

2

⁢

λ
m

(
2
)

⁢

n
m

⁡

(

λ
m

)

×

d
m

≥

0.6
⁢

λ
m

(
3
)

First claim

The invention claimed is:

1. An organic electroluminescence element, comprising:
a substrate having a light transmissive property;
a light diffusion layer on a surface of the substrate;
a light transmissive electrode on a surface of the light diffusion layer;
a light reflective electrode paired with the light transmissive electrode; and
multiple light emitting layers which are spaced from each other and are between the light transmissive electrode and the light reflective electrode,
the multiple light emitting layers including an m-th light emitting layer which is an m-th closest light emitting layer to the light reflective electrode, where m is an integer equal to or more than 1;
λ m representing a weighted average emission wavelength of the m-th light emitting layer;
Ø(λ m ) Ø m representing a phase shift of light produced by the m-th light emitting layer caused by the light reflective electrode which is defined by a following expression (1):

[

FORMULA
⁢

⁢
1

]

ϕ
⁡

(

λ
m

)

=

tan

-
1

⁢

{

2
⁢

(

n
s

⁢

k
r

-

n
r

⁢

k
s

)

n
s
2

-

n
r
2

+

k
s
2

-

k
r
2

}

(
1
)

wherein n s and k s represent a refractive index and an extinction coefficient of a layer in contact with the light reflective electrode, respectively, and n r and k r represent a refractive index and an extinction coefficient of the light reflective electrode, respectively, and n s , n r , k s , and k r are functions of λ m ;
an average refractive index of a medium filling a space between the light reflective electrode and the m-th light emitting layer being represented by n m (λ m );
a distance from the light reflective electrode to the m-th light emitting layer being represented by d m ; and
each of at least two of the multiple light emitting layers satisfying relations defined by following expressions (2) and (3):

⁢

[

FORMULA
⁢

⁢
2

]

ϕ
⁡

(

λ
m

)

×

λ
m

4
⁢
π

+

l
-
0.1

2

⁢

λ
m

≤

n
m

⁡

(

λ
m

)

×

d
m

≤

Assignees

• Panasonic Corp

Inventors

• Yamae Kazuyuki
• Ide Nobuhiro
• Takano Hitomichi

Classifications

• H10K59/8791

  Arrangements for improving contrast, e.g. preventing reflection of ambient light · CPC title

• H10K59/878

  comprising reflective means · CPC title

• H10K59/877

  comprising scattering means · CPC title

• H10K59/875

  Arrangements for extracting light from the devices · CPC title

• H10K50/13

  comprising stacked EL layers within one EL unit · CPC title