Display device

1. A display device comprising:

a substrate;

a light-emitting element on the substrate;

a planarization layer on the light-emitting element;

a first refractive index layer outside a light emission region of the light-emitting element on the planarization layer and including a total reflection inclination surface totally reflecting light emitted from the light-emitting element in a front direction and a refraction inclination surface refracting light emitted from the light-emitting element in the front direction;

a second refractive index layer outside the light emission region of the light-emitting element, wherein the second refractive index layer is adjacent to and extends over a portion of the first refractive index layer to be in contact with the refraction inclination surface and having a smaller refractive index than a refractive index of the first refractive index layer; and

a third refractive index layer on the first refractive index layer and the second refractive index layer to be in contact with the total reflection inclination surface and having a larger refractive index than the refractive index of the first refractive index layer.

2. The display device of claim 1 , wherein a refractive index difference between the first refractive index layer and the second refractive index layer is 0.05 or more.

3. The display device of claim 1 , wherein a refractive index difference between the first refractive index layer and the third refractive index layer is 0.05 or more.

4. The display device of claim 1 , wherein

a thickness of the second refractive index layer is greater than or equal to a thickness of the first refractive index layer.

5. The display device of claim 1 , wherein a refraction inclination angle formed by the refraction inclination surface with an upper surface of the substrate is less than 90 degrees and 50 degrees or more.

6. The display device of claim 1 , wherein the first refractive index layer has a ring shape surrounding a light-emitting region of the light-emitting element on a plane.

7. The display device of claim 6 , wherein the total reflection inclination surface is an inner side surface of the ring-shaped first refractive index layer.

8. The display device of claim 6 , wherein the refraction inclination surface is an outer side surface of the ring-shaped first refractive index layer.

9. A display device comprising:

a substrate;

a light-emitting element on the substrate;

a planarization layer on the light-emitting element;

a first refractive index layer outside a light emission region of the light-emitting element on the planarization layer and including a refraction inclination surface refracting light emitted from the light-emitting element in a front direction;

a second refractive index layer outside the light emission region of the light-emitting element, wherein the second refractive index layer is adjacent to and extends over a portion of the first refractive index layer to be in contact with the refraction inclination surface and including a total reflection inclination surface totally reflecting light emitted from the light-emitting element in the front direction and having a larger refractive index than a refractive index of the first refractive index layer; and

a third refractive index layer on the second refractive index layer to be in contact with the total reflection inclination surface and having a larger refractive index than the refractive index of the second refractive index layer.

10. The display device of claim 9 , wherein a refractive index difference between the first refractive index layer and the second refractive index layer is 0.05 or more.

11. The display device of claim 9 , wherein a refractive index difference between the second refractive index layer and the third refractive index layer is 0.05 or more.

12. The display device of claim 9 , wherein a refraction inclination angle of the refraction inclination surface formed by an upper surface of the substrate is less than a total reflection inclination angle of the total reflection inclination surface formed by the upper surface of the substrate.

13. The display device of claim 9 , wherein

a thickness of the second refractive index layer is greater than or equal to a thickness of the first refractive index layer.

14. The display device of claim 9 , further comprising:

a first touch electrode between the planarization layer and the first refractive index layer; and

a second touch electrode between the first refractive index layer and the second refractive index layer.

15. The display device of claim 9 , further comprising:

a touch insulating layer between the planarization layer and the first refractive index layer;

a first touch electrode between the planarization layer and the touch insulating layer; and

a second touch electrode between the touch insulating layer and the first refractive index layer.

16. A display device comprising:

a substrate;

a light-emitting element on the substrate;

a first refractive index layer comprising:

a total reflection inclination surface configured to totally reflect light emitted from the light-emitting element in a front direction; and

a refraction inclination surface configured to refract light emitted from the light-emitting element in the front direction and sloping from a top of the refraction inclination surface, that is a furthest point of the refraction inclination surface along a light emission direction of the light-emitting element, to a bottom of the refraction inclination surface, that is a closest point of the refraction inclination surface along the light emission direction, in a direction away from the light-emitting element,

wherein a region wherein a light is emitted in the front direction in one pixel includes a front light region corresponding a light emission region of the light-emitting element, a total reflection light region corresponding to the total reflection inclination surface, and a refraction light region corresponding to the refraction inclination surface, and

wherein the refraction inclination surface is an interface between the first refractive index layer having a first refractive index and a second refractive index layer having a second refractive index that is smaller than the first refractive index.

17. The display device of claim 16 , wherein

the total reflection inclination surface is an interface between the first refractive index layer and a third refractive index layer having a third refractive index that is larger than the first refractive index.

18. The display device of claim 16 , wherein

the first refractive index layer has a ring shape surrounding the light emission region of the light-emitting element on a plane.