# US 2014/0151672 A1 · Light-emitting element and organic electroluminescent display device

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- Number: US 2014/0151672 A1
- Document ID: US20140151672A1
- Status: Published application
- Kind: A1
- Application number: 14/173,594
- Filed: 2014-02-05
- Published: 2014-06-05
- Earliest claimed: 2008-07-29
- Assignees: Sony Corporation
- Applicants: Sony Corporation
- Inventors: Jiro Yamada; Eisuke Negishi; Hirofumi Nakamura; Akifumi Nakamura; Tadahiko Yoshinaga
- Web page: https://patentgrep.com/patent/US20140151672A1

## CPC

- H05B 33/24: of metallic reflective layers (H05B33/26 takes precedence)
- H10K 59/876: {comprising a resonant cavity structure, e.g. Bragg reflector pair}
- H10K 59/12: Active-matrix OLED [AMOLED] displays
- H10K 59/131: Interconnections, e.g. wiring lines or terminals
- H10K 59/80524: {Transparent cathodes, e.g. comprising thin metal layers}
- H10K 2102/3026: {Top emission}
- H10K 2102/351: {Thickness}
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

Provided is a light-emitting element in the structure and configuration of causing no possibility of a short circuit between first and second electrodes even if there is any foreign substance or a protrusion on the first electrode. Such a light-emitting element is configured to include, in order, a first electrode 21, an organic layer 23 including a light-emitting layer made of an organic light-emitting material, a semi-transmissive/reflective film 40, a resistance layer 50, and a second electrode 22. The first electrode 21 reflects a light coming from the light-emitting layer, and the second electrode 22 passes through a light coming from the semi-transmissive/reflective film 40 after passing therethrough. The semi-transmissive/reflective film on the organic layer 23 has an average film thickness of 1 nm to 6 nm both inclusive.

## Claims

### Claim 1

A light-emitting element, comprising:
(A) a first electrode;
(B) an organic layer including a light-emitting layer made of an organic light-emitting material;
(C) a semi-transmissive/reflective film;
(D) a resistance layer; and
(E) a second electrode,
wherein,
the first electrode is configured to reflect light coming from the light-emitting layer,
the second electrode is configured to allow light coming from the semi-transmissive/reflective film to be transmitted therethrough,
the semi-transmissive/reflective film on the organic layer has an average film thickness of 1 nm to 6 nm both inclusive,
the light from the light-emitting layer is made to resonate between (i) a first interface between the first electrode and the organic layer, and (ii) a second interface between the semi-transmissive/reflective film and the organic layer, and
a part of the light is emitted from the semi-transmissive/reflective film.

### Claim 2 (depends on 1)

The light-emitting element according to claim 1, wherein
the semi-transmissive/reflective film is made of alloys of magnesium-silver, aluminum, or silver.

### Claim 3 (depends on 1)

The light-emitting element according to claim 1,
wherein,
a material configuring the resistance layer has an electrical resistivity of 1×106 Ωm to 1×1010 Ωm both inclusive, and
the resistance layer above the organic layer has a thickness of 0.1 μm to 2 μm both inclusive.

### Claim 4 (depends on 1)

The light-emitting element according to claim 1,
wherein,
the first electrode includes a foreign substance or a protrusion,
the semi-transmissive/reflective film is not formed to a region proximal to the foreign substance or the protrusion, and
the resistance layer is in a region between (i) a portion of the semi-transmissive/reflective film in the periphery of the foreign substance or the protrusion, and (ii) a portion of the first electrode under the foreign substance or beneath the protrusion.

### Claim 5 (depends on 1)

The light-emitting element according to claim 1,
wherein,
when a distance from the first interface being an interface between the first electrode and the organic layer to a position on the light-emitting layer where a level of light emission is maximum is L1, an optical distance thereof is OL1, a distance from the second interface being an interface between the semi-transmissive/reflective film and the organic layer to the position on the light-emitting layer where a level of light emission is maximum is L2, and an optical distance thereof is OL2, expressions (1-1) and (1-2) below are satisfied,
0.7{−Φ1/(2π)+m1}≦2×OL1/λ≦1.2{−Φ1/(2π)+m1} (1-1)
0.7{−Φ2/(2π)+m2}≦2×OL2/λ≦1.2{−Φ2/(2π)+m2} (1-2)
where λ is a maximum peak wavelength in a spectrum of the light generated in the light-emitting layer,
Φ1 is an amount of phase shift (unit: radian) of a reflected light generated on the first interface (where −2π<Φ1<0)
Φ2 is an amount of phase shift (unit: radian) of a reflected light generated on the second interface (where −2π<Φ2<0, and
a value of (m1, m2) is (0, 0), (1, 0), or (0, 1).

### Claim 6 (depends on 1)

The light-emitting element according to claim 1,
wherein,
when an optical distance between the first interface being an interface between the first electrode and the organic layer and the second interface being an interface between the semi-transmissive/reflective film and the organic layer is L, a sum of phase shift to be observed when the light generated in the light-emitting layer is reflected on the first and second interfaces is Φ radian, and a maximum peak wavelength in a spectrum of the light generated in the light-emitting layer is λ, an expression of
0.7<{(2L)/λ+Φ/(2π)}<1.3
or
−0.3<{(2L)/λ+Φ/(2π)}<0.3
is satisfied.

### Claim 7

A light-emitting element, comprising:
(A) a first electrode;
(B) an organic layer including a light-emitting layer made of an organic light-emitting material;
(C) a semi-transmissive/reflective film;
(D) a resistance layer; and
(E) a second electrode,
wherein,
the first electrode is configured to reflect light coming from the light-emitting layer,
the second electrode is configured to transmit light coming from the semi-transmissive/reflective film after passing through the semi-transmissive/reflective film, and
when a distance from a first interface between the first electrode and the organic layer to a position on the light-emitting layer where a level of light emission is maximum is L1, an optical distance thereof is OL1, a distance from a second interface between the semi-transmissive/reflective film and the organic layer to a position on the light-emitting layer where a level of light emission is maximum is L2, and an optical distance thereof is OL2, expressions (1-1) and (1-2) below are satisfied,
0.7{−Φ1/(2π)+m1}≦2×OL1/λ≦1.2{−Φ1/(2π)+m1} (1-1)
0.7{−Φ2/(2π)+m2}≦2×OL2/λ≦1.2{−Φ2/(2π)+m2} (1-2)
where λ is a maximum peak wavelength in a spectrum of a light generated in the light-emitting layer,
Φ1 is an amount of phase shift (unit: radian) of a reflected light generated on the first interface (where −2π<φ1<0)
Φ2 is an amount of phase shift (unit: radian) of a reflected light generated on the second interface (where −2π<Φ2<0), and
a value of (m1, m2) is (0, 0), (1, 0), or (0, 1).

### Claim 8

A light-emitting element, comprising:
(A) a first electrode;
(B) an organic layer including a light-emitting layer made of an organic light-emitting material;
(C) a semi-transmissive/reflective film;
(D) a resistance layer; and
(E) a second electrode,
wherein,
the first electrode is configured to reflect light coming from the light-emitting layer,
the second electrode is configured to transmit light coming from the semi-transmissive/reflective film after passing through the semi-transmissive/reflective film, and
when an optical distance between a first interface between the first electrode and the organic layer and a second interface between the semi-transmissive/reflective film and the organic layer is L, a sum of phase shift to be observed when a light generated in the light-emitting layer is reflected on the first and second interfaces is 4 radian, and a maximum peak wavelength in a spectrum of the light generated in the light-emitting layer is λ,
an expression of
0.7<{(2L)/λ+Φ/(2π)}<1.3
or
−0.3<{(2L)/λ+Φ/(2π)}<0.3
is satisfied.

### Claim 9

An organic electroluminescent display device, including a plurality of organic electroluminescent elements each comprising:
(a) a first electrode;
(b) an insulation layer including an aperture, and from a bottom portion of the aperture, the first electrode is exposed;
(c) an organic layer disposed from the above of a portion of the first electrode exposed from the bottom portion of the aperture to a portion of the insulation layer around the aperture, and includes a light-emitting layer made of an organic light-emitting material;
(d) a semi-transmissive/reflective film formed at least on the organic layer;
(e) a resistance layer covering the semi-transmissive/reflective film; and
(f) a second electrode formed on the resistance layer,
wherein,
the first electrode reflects a light coming from the light-emitting layer,
the second electrode passes through a light coming from the semi-transmissive/reflective film after passing therethrough, and
a portion of the semi-transmissive/reflective film on the insulation layer is at least partially discontinuous.

### Claim 10 (depends on 9)

The organic electroluminescent display device according to claim 9, wherein
the semi-transmissive/reflective film on the organic layer has an average film thickness of 1 nm to 6 nm both inclusive.

### Claim 11 (depends on 9)

The organic electroluminescent display device according to claim 9, wherein
the semi-transmissive/reflective film is made of alloys of magnesium-silver, aluminum, or silver.

### Claim 12 (depends on 9)

The organic electroluminescent display device according to claim 9,
wherein,
a material configuring the resistance layer has an electrical resistivity of 1×106 Ωm to 1×1010 Ωm both inclusive, and
the resistance layer above the organic layer has a thickness of 0.1 μm to 2 μm both inclusive.

### Claim 13 (depends on 9)

The organic electroluminescent display device according to claim 9,
wherein,
the first electrode includes a foreign substance or a protrusion,
the semi-transmissive/reflective film is not formed to a region proximal to the foreign substance or the protrusion, and
the resistance layer is in a region between (i) a portion of the semi-transmissive/reflective film in the periphery of the foreign substance or the protrusion, and (ii) a portion of the first electrode under the foreign substance or beneath the protrusion.

### Claim 14 (depends on 9)

The organic electroluminescent display device according to claim 9,
wherein,
a light generated in the light-emitting layer is made to resonate between a first interface between the first electrode and the organic layer and a second interface between the semi-transmissive/reflective film and the organic layer, and
a part of the resulting light is emitted from the semi-transmissive/reflective film.

### Claim 15 (depends on 14)

The organic electroluminescent display device according to claim 14,
wherein,
when a distance from the first interface between the first electrode and the organic layer to a position on the light-emitting layer where a level of light emission is maximum is L1, an optical distance thereof is OL1, a distance from the second between the semi-transmissive/reflective film and the organic layer to a position on the light-emitting layer where a level of light emission is maximum is L2, and an optical distance thereof is OL2, expressions (1-1) and (1-2) below are satisfied,
0.7{−Φ1/(2π)+m1}≦2×OL1/λ≦1.2{−Φ1/(2π)+m1} (1-1)
0.7{−Φ2/(2π)+m2}≦2×OL2/λ≦1.2{−Φ2/(2π)+m2} (1-2)
where λ is a maximum peak wavelength in a spectrum of the light generated in the light-emitting layer,
Φ1 is an amount of phase shift (unit: radian) of a reflected light generated on the first interface (where −2π<Φ1<0)
Φ2 is an amount of phase shift (unit: radian) of a reflected light generated on the second interface (where −2π<Φ2<0), and
a value of (m1, m2) is (0, 0), (1, 0), or (0, 1).

### Claim 16 (depends on 14)

The organic electroluminescent display device according to claim 14,
wherein,
when an optical distance between the first interface between the first electrode and the organic layer and the second interface between the semi-transmissive/reflective film and the organic layer is L, a sum of phase shift to be observed when the light generated in the light-emitting layer is reflected on the first and second interfaces is Φ radian, and a maximum peak wavelength in a spectrum of the light generated in the light-emitting layer is λ, an expression of
0.7<{(2L)/λ+Φ/(2π)}<1.3
or
−0.3<{(2L)/λ+Φ/(2π)}<0.3
is satisfied.