Light-emitting device, method for manufacturing the same, display device, and electronic apparatus

1. A light-emitting device comprising:

a substrate which has

a first edge,

a second edge being opposed to the first edge, and

a plane portion being arranged between the first edge and the second edge; and

a plurality of light-emitting elements which are provided above the plane portion of the substrate in a light-emitting region, each of plurality of the light-emitting elements having:

a cathode;

an anode;

at least one light-emitting layer which is provided between the cathode and the anode and which emits light when a voltage is applied between the cathode and the anode;

a cathode terminal which is electrically coupled between the cathode and a power source applying the voltage, the cathode terminal being provided in a connecting region outside the light-emitting region,

the cathode terminal having a first portion and a second portion,

the first portion being provided between the first edge and the light-emitting region when viewed from a vertical direction to the plane portion of the substrate;

the second portion being provided between the second edge and the light-emitting region when viewed from a vertical direction to the plane portion of the substrate;

a functional layer which extends from the light-emitting region to the connecting region, the functional layer being provided between the cathode and the cathode terminal in the connecting region and between the light-emitting layer and the cathode in the light-emitting region, the functional layer adjusting an amount of electrons; and

an auxiliary cathode that is electrically coupled between the cathode and the cathode terminal and is not overlapped with the light-emitting elements,

the auxiliary cathode having a third portion which is positioned in the connecting region, the third portion overlapping the cathode and the cathode terminal when viewed from a vertical direction to the plane portion of the substrate,

the functional layer contacting at least a part of the cathode and the auxiliary cathode,

an average thickness of the functional layer being 0.2 nm to 10 nm.

2. The light-emitting device according to claim 1 ,

wherein the cathode terminal and the functional layer are at least partially overlapped with each other in a thickness direction of the functional layer.

3. The light-emitting device according to claim 1 ,

the auxiliary cathode including a material having a higher electrical conductivity than that of the cathode.

4. The light-emitting device according to claim 3 ,

wherein the auxiliary cathode is disposed in contact with the cathode.

5. The light-emitting device according to claim 1 ,

further comprising:

an electron injection layer which is provided between the cathode and the light-emitting layer to be overlapped with at least part of the cathode and at least part of the light-emitting layer in a thickness direction of the cathode,

wherein the electron injection layer and the functional layer includes the same material.

6. The light-emitting device according to claim 5 ,

wherein the functional layer is provided to be overlapped in a thickness direction thereof with the light-emitting layer and also functions as the electron injection layer of the light-emitting device.

7. The light-emitting device according to claim 1 ,

further comprising:

a switching element which controls an electrical connection between a power source and the anode,

wherein when the switching element is operated to cut off the electrical connection, the functional layer has certain insulating properties so as to prevent movement of electrons from the cathode terminal to the cathode.

8. The light-emitting device according to claim 1 ,

further comprising:

a switching element which controls an electrical connection between a power source and the anode,

wherein when the switching element is operated to connect the electrical connection, the functional layer has certain insulating properties so as not to prevent movement of electrons from the cathode terminal to the cathode.

9. The light-emitting device according to claim 1 ,

wherein the functional layer includes at least one of a ferroelectric material, an alkali metal oxide, an alkali metal halide, an alkaline earth metal oxide, and an alkaline earth metal halide.

10. The light-emitting device according to claim 1 ,

wherein the functional layer includes a lithium compound.

11. The light-emitting device according to claim 1 ,

wherein the light-emitting layers are provided between the cathode and the anode.

12. The light-emitting device according to claim 1 ,

wherein the light-emitting layers emit different colors from each other.

13. A method for manufacturing a light-emitting device comprising:

forming an anode and a cathode terminal above a substrate, the cathode terminal being provided in a connecting region;

forming an auxiliary cathode above the cathode terminal;

forming a light-emitting layer above the anode which emits light when a voltage is applied;

wherein the cathode terminal and the auxiliary cathode are formed in an area which does not overlap the light-emitting layer;

forming a functional layer which includes a material having insulating properties and which overlaps the light-emitting layer and the auxiliary cathode in plan view; and

forming a cathode above an electron adjust layer,

wherein the cathode terminal is electrically coupled between the cathode and a power source applying the voltage,

wherein the auxiliary cathode is electrically coupled between the cathode and the cathode terminal,

wherein the functional layer contacts at least a part of the cathode and the auxiliary cathode, and

wherein the functional layer is formed with an average thickness of 0.2 nm to 10 nm.

14. A display device comprising the light-emitting device according to claim 1 .

15. An electronic apparatus comprising the display device according to claim 14 .

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

the functional layer being provided between the auxiliary cathode and the cathode terminal.