Light emitting device

1. A light emitting device comprising:

a plurality of organic electroluminescent sections each including a first reflective layer, an organic light emitting layer and a second reflective layer in this order; and

a light extraction surface from which light emitted from each of the organic electroluminescent sections through the second reflective layer is extracted,

wherein the second reflective layer includes a first metal layer, a transparent layer and a second metal layer in this order from the organic light emitting layer side, and

in each of the organic electroluminescent sections, a microcavity structure is formed by a structure that includes a first reflective interface on the organic light emitting layer side of the first reflective layer, a second reflective interface on the organic light emitting layer side of the first metal layer, and a third reflective interface on the organic light emitting layer side of the second metal layer.

2. The light emitting device according to claim 1 ,

wherein an optical path between the second reflective interface and the third reflective interface is not more than a center wavelength of the light emitted from the corresponding organic light emitting layer.

3. The light emitting device according to claim 1 ,

wherein the plurality of organic electroluminescent sections include a plurality of first organic electroluminescent sections, and a plurality of second organic electroluminescent sections, and

in each of the first organic electroluminescent sections and each of the second organic electroluminescent sections,

the microcavity structure is configured in such a manner as to satisfy the following expressions (A) to (F):

2 La 1 /λa 1 +a 1/(2π)= Na   (A)

λ a −150 <λa 1 <λa +80   (B)

2 La 2 /λa 2 +φa 2/(2π)= Ma   (C)

λ a 80 <λa 2 <λa +80   (D)

2 La 3 /λa 3 +a 3/(2π)=Ka+½  (E)

λ a −150 <λa 3 <λa +150   (F)

where

La 1 is an optical path between the first reflective interface and a light emission center of the organic light emitting layer of the first organic electroluminescent section;

La 2 is an optical path between the second reflective interface and the light emission center of the organic light emitting layer of the first organic electroluminescent section;

La 3 is an optical path between the third reflective interface and the light emission center of the organic light emitting layer of the first organic electroluminescent section;

φa1 is a phase change when the light emitted from the organic light emitting layer is reflected by the first reflective interface, in the first organic electroluminescent section;

φa2 is a phase change when the light emitted from the organic light emitting layer is reflected by the second reflective interface, in the first organic electroluminescent section;

φa3 is a phase change when the light emitted from the organic light emitting layer is reflected by the third reflective interface, in the first organic electroluminescent section;

λa is a center wavelength in a light emission spectrum of the organic light emitting layer of the first organic electroluminescent section;

λa1 is a wavelength satisfying the expression (B);

λa2 is a wavelength satisfying the expression (D);

λa3 is a wavelength satisfying the expression (F); and

Na, Ma and Ka are each an integer of not less than 0.

4. The light emitting device according to claim 3 ,

wherein in each of the first organic electroluminescent sections and each of the second organic electroluminescent sections,

the microcavity structure is configured in such a manner as to satisfy the following expressions (G) to (L):

2 Lc 1 /λc 1 +φc 1/(2π)= Nc   (G)

λ c −150 <λc 1 <λc +80   (H)

2 Lc 2 /λc 2 +φc 2/(2π)= Mc   (I)

λ c −80 <λc 2 <λc +80   (J)

2 Lc 3 /λc 3 +φc 3/(2π)= Kc   (K)

λ c −150 <λc 3 <λc +150   (L)

where

Lc 1 is an optical path between the first reflective interface and a light emission center of the organic light emitting layer of the second organic electroluminescent section;

Lc 2 is an optical path between the second reflective interface and the light emission center of the organic light emitting layer of the second organic electroluminescent section;

Lc 3 is an optical path between the third reflective interface and the light emission center of the organic light emitting layer of the second organic electroluminescent section;

φc1 is a phase change when the light emitted from the organic light emitting layer is reflected by the first reflective interface, in the second organic electroluminescent section;

φc2 is a phase change when the light emitted from the organic light emitting layer is reflected by the second reflective interface, in the second organic electroluminescent section;

φc3 is a phase change when the light emitted from the organic light emitting layer is reflected by the third reflective interface, in the second organic electroluminescent section;

λc is a center wavelength in a light emission spectrum of the organic light emitting layer of the second organic electroluminescent section;

λc1 is a wavelength satisfying the expression (H);

λc2 is a wavelength satisfying the expression (J);

λc3 is a wavelength satisfying the expression (L); and

Nc, Mc and Kc are each an integer of not less than 0.

5. The light emitting device according to claim 1 ,

wherein the plurality of organic electroluminescent sections include a plurality of first organic electroluminescent sections that emit light in a first wavelength band and a plurality of second organic electroluminescent sections that emit light in a second wavelength band on a shorter wavelength side than the first wavelength band, and

in each of the first organic electroluminescent sections and each of the second organic electroluminescent sections,

the microcavity structure is configured such that the first reflective interface and the second reflective interface intensify light in the first wavelength band and light in the second wavelength band, and that the third reflective interface weakens the light in the first wavelength band and intensifies the light in the second wavelength band.

6. The light emitting device according to claim 1 ,

wherein the plurality of organic electroluminescent sections include a plurality of first organic electroluminescent sections and a plurality of second organic electroluminescent sections, and

in each of the first organic electroluminescent sections and each of the second organic electroluminescent sections,

the microcavity structure is configured in such a manner as to satisfy the following expressions (M) to (R):

2 La 1 /λa 1 +a 1/(2π)= Na   (M)

λ a −150 <λa 1 <λa +80   (N)

2 La 2 /λa 2 +φa 2/(2π)= Ma   (O)

λ a −80 <λa 2 <λa +80   (P)

2 La 3 /λa 3 +φa 3/(2π)= Ka   (Q)

λ a −150 <λa 3 <λa +150   (R)

where

La 1 is an optical path between the first reflective interface and a light emission center of the organic light emitting layer of the first organic electroluminescent section;

La 2 is an optical path between the second reflective interface and the light emission center of the organic light emitting layer of the first organic electroluminescent section;

La 3 is an optical path between the third reflective interface and the light emission center of the organic light emitting layer of the first organic electroluminescent section;

φa1 is a phase change when the light emitted from the organic light emitting layer is reflected by the first reflective interface, in the first organic electroluminescent section;

φa2 is a phase change when the light emitted from the organic light emitting layer is reflected by the second reflective interface, in the first organic electroluminescent section;

φa3 is a phase change when the light emitted from the organic light emitting layer is reflected by the third reflective interface, in the first organic electroluminescent section;

λa is a center wavelength in a light emission spectrum of the organic light emitting layer of the first organic electroluminescent section;

λa1 is a wavelength satisfying the expression (N);

λa2 is a wavelength satisfying the expression (P);

λa3 is a wavelength satisfying the expression (R); and

Na, Ma and Ka are each an integer of not less than 0.

7. The light emitting device according to claim 6 ,

wherein in each of the first organic electroluminescent sections and each of the second organic electroluminescent sections,

the microcavity structure is configured in such a manner as to satisfy the following expressions (S) to (X):

2 Lc 1 /λc 1 +φc 1/(2π)= Nc   (S)

λ c −150 <λc 1 <λc +80   (T)

2 Lc 2 /λc 2 +φc 2/(2π)= Mc   (U)

λ c −80 <λc 2 <λc +80   (V)

2 Lc 3 /λc 3 +c 3/(2π)= Kc +½  (W)

λ c −150 <λc 3 <λc +150   (X)

where

Lc 1 is an optical path between the first reflective interface and a light emission center of the organic light emitting layer of the second organic electroluminescent section;

Lc 2 is an optical path between the second reflective interface and the light emission center of the organic light emitting layer of the second organic electroluminescent section;

Lc 3 is an optical path between the third reflective interface and the light emission center of the organic light emitting layer of the second organic electroluminescent section;

φc1 is a phase change when the light emitted from the organic light emitting layer is reflected by the first reflective interface, in the second organic electroluminescent section;

φc2 is a phase change when the light emitted from the organic light emitting layer is reflected by the second reflective interface, in the second organic electroluminescent section;

φc3 is a phase change when the light emitted from the organic light emitting layer is reflected by the third reflective interface, in the second organic electroluminescent section;

λc is a center wavelength in a light emission spectrum of the organic light emitting layer of the second organic electroluminescent section;

λc1 is a wavelength satisfying the expression (T);

λc2 is a wavelength satisfying the expression (V);

λc3 is a wavelength satisfying the expression (X); and

Nc, Mc and Kc are each an integer of not less than 0.

8. The light emitting device according to claim 1 ,

wherein the plurality of organic electroluminescent sections include a plurality of first organic electroluminescent sections that emit light in a first wavelength band and a plurality of second organic electroluminescent sections that emit light in a second wavelength band on a shorter wavelength side than the first wavelength band, and

in each of the first organic electroluminescent sections and each of the second organic electroluminescent sections,

the microcavity structure is configured such that the first reflective interface and the second reflective interface intensify light in the first wavelength band and light in the second wavelength band, and that the third reflective interface intensifies the light in the first wavelength band and weakens the light in the second wavelength band.

9. The light emitting device according to claim 1 ,

wherein the first metal layer is thicker than the second metal layer.

10. The light emitting device according to claim 9 ,

wherein a total thickness of the first metal layer and the second metal layer is not less than 15 nm.

11. The light emitting device according to claim 1 , further comprising:

a circuit substrate formed with a driving circuit for driving each of the organic electroluminescent sections, on a side opposite to the light extraction surface, in positional relation with each of the organic electroluminescent sections.

12. The light emitting device according to claim 1 ,

wherein the transparent layer is formed by using a transparent conductive material, and

the first metal layer, the transparent layer and the second metal layer are electrically connected to one another and function as an electrode on the light extraction surface side.

13. The light emitting device according to claim 1 ,

wherein the transparent layer is formed by using a transparent dielectric material,

the first metal layer and the second metal layer are electrically separated from each other through the transparent layer, and

the second metal layer functions as an electrode on the light extraction surface side.

14. The light emitting device according to claim 1 ,

wherein the organic light emitting layer is a printed layer.