# US 10,483,480 B2 · Display device

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- Number: US 10,483,480 B2
- Document ID: US10483480B2
- Status: Granted
- Kind: B2
- Application number: 16/047,076
- Filed: 2018-07-27
- Published: 2019-02-14
- Granted: 2019-11-19
- Earliest claimed: 2017-08-14
- Assignees: Japan Display Inc.
- Applicants: Japan Display Inc.
- Inventors: Koji Yasukawa
- Web page: https://patentgrep.com/patent/US10483480B2

## CPC

- H10K 50/15: Hole transporting layers
- H10K 50/17: Carrier injection layers
- H10K 59/8051: {Anodes}
- H10K 59/871: {Self-supporting sealing arrangements}
- H10K 77/111: {Flexible substrates}
- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 59/12: Active-matrix OLED [AMOLED] displays
- H10K 59/8052: {Cathodes}
- H10K 59/872: {Containers}
- H10K 59/8791: {Arrangements for improving contrast, e.g. preventing reflection of ambient light}
- H10K 2101/30: Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
- H10K 2102/00: Constructional details relating to the organic devices covered by this subclass
- H10K 2102/103: {comprising indium oxides, e.g. ITO}
- H10K 2102/311: {Flexible OLED}
- H10K 2102/351: {Thickness}
- Y02E 10/549: Organic PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A display device including a pixel electrode, a counter electrode, and an organic layer arranged between the pixel electrode and the counter electrode, wherein the organic layer includes a hole injection layer in contact with the pixel electrode, a hole transport layer above the hole injection layer, a light emitting layer and an electron transport layer, the hole injection layer includes an inorganic material, and the inorganic material has a work function of 4.4 eV or less and includes one element or a plurality of elements selected from Na, Mg, K, Rb, Sr, Cs, Ba, Fr, Ca, Yb, Li, Al, Sm, Er and Ho, or a fluoride or an oxide of the elements.

## Claims

### Claim 1

A display device comprising:
a pixel electrode, a counter electrode, and an organic layer arranged between the pixel electrode and the counter electrode,
wherein
the organic layer includes a hole injection layer in contact with the pixel electrode, a hole transport layer above the hole injection layer, a light emitting layer and an electron transport layer;
the hole injection layer includes an inorganic material;
the inorganic material has a work function of 4.4 eV or less,
a surface roughness of the pixel electrode is 20 nm or more, and a gap length between a projection and a depression of the surface of the pixel electrode is 40 nm or more, and
a thickness of the hole injection layer is smaller than the surface roughness of the pixel electrode.

### Claim 2 (depends on 1)

The display device according to claim 1, wherein the surface of the pixel electrode is indium tin oxide or indium zinc oxide.

### Claim 3 (depends on 1)

The display device according to claim 1, wherein the hole injection layer includes the inorganic material and an organic material.

### Claim 4 (depends on 3)

The display device according to claim 3, wherein the organic material is an amine-based organic material.

### Claim 5 (depends on 4)

The display device according to claim 4, wherein the inorganic material is magnesium fluoride.

### Claim 6 (depends on 1)

The display device according to claim 1, further comprising an electron blocking layer arranged between the hole transport layer and the light emitting layer, and a hole blocking layer arranged between the light emitting layer and the electron transport layer.

### Claim 7 (depends on 1)

The display device according to claim 1, wherein the pixel electrode is arranged above a first substrate and the first substrate has flexibility.

### Claim 8 (depends on 7)

The display device according to claim 7, further comprising a second substrate facing the first substrate and covering the counter electrode;
wherein the second substrate has flexibility.

### Claim 9 (depends on 8)

The display device according to claim 8, further comprising a sealing member is arranged between the first substrate and the second substrate.

### Claim 10 (depends on 1)

The display device according to claim 1, wherein the inorganic material includes one element or a plurality of elements selected from Na, Mg, K, Sr, Cs, Ba, Fr, Ca, Rb, Yb, Li, Al, Sm, Er and Ho, or a fluoride or an oxide of these elements.

### Claim 11 (depends on 1)

The display device according to claim 1, wherein the thickness of the hole injection layer is 5 nm or less.