Display device, backlight unit, light emitting module and lens

1. A lens, comprising:

a light entering part having a concave shape in a lower region of the lens, and on which light emitted from a light emitting device is to be incident;

a light exiting part through which the incident light is emitted to the outside; and

a flange connecting the light exiting part and a lower surface of the lens and having a side surface substantially perpendicular to the lower surface of the lens, the flange having a planar shape different from a planar shape of the light exiting part and protruding outwardly from the light exiting part in plan view along a circumference of the light exiting part,

wherein the lower surface comprises a protruding part with a predetermined curvature to surround the light entering part, and

wherein each of the light entering part and the light exiting part has a major axis and a minor axis in plan view, and the major axis of the light entering part is orthogonal to the major axis of the light exiting part.

2. The lens of claim 1 , wherein an inner surface of the light entering part comprises a light incident vertical surface extending from the protruding part, and a light incident inclined surface extending from the light incident vertical surface.

3. The lens of claim 1 , wherein the lens further comprises a plurality of legs coupled to the lower surface of the lens, and the plurality of legs is disposed outside of the protruding part.

4. The lens of claim 1 , wherein the thickness of the flange is greater at a major axis of the light exiting part than at a minor axis of the light exiting part.

5. The lens of claim 4 , wherein a shortest distance from one end of the light exiting part of the lens at the major axis thereof to one end of the flange at the major axis of the flange is different from a shortest distance from one end of the light exiting part of the lens at the minor axis thereof to one end of the flange at the minor axis of the flange.

6. The lens of claim 1 , wherein the light exiting part has a substantially elliptical planar shape and the flange has a substantially circular planar shape.

7. The lens of claim 6 , wherein the thickness of the flange gradually decreases from the major axis of the light exiting part to the minor axis of the light exiting part along the circumference.

8. The lens of claim 7 , wherein:

the light entering part comprises a light incident vertical surface extending from the lower surface of the lens and a light incident inclined surface extending upward from the light incident vertical surface; and

a height of the light incident vertical surface from the lower surface of the lens is less than the thickness of the flange at the minor axis of the light exiting part.

9. The lens of claim 1 , wherein the flange protrudes outwardly along the entire circumference of the light exiting part in plan view.

10. A light emitting module, comprising:

a substrate;

a plurality of light emitting devices disposed on the substrate; and

a lens disposed over at least one of the plurality of light emitting devices to spread light emitted from the light emitting devices,

wherein the lens comprises:

a light entering part on which light emitted from the light emitting device is incident;

a light exiting part through which the incident light is emitted to the outside; and

a flange connecting the light exiting part and a lower surface of the lens and having a side surface substantially perpendicular to the lower surface of the lens, the flange having a planar shape different from a planar shape of the light exiting part and protruding outwardly from the light exiting part in plan view along a circumference of the light exiting part,

wherein each of the light entering part and the light exiting part has a major axis and a minor axis in plan view, and the major axis of the light entering part is orthogonal to the major axis of the light exiting part, and

wherein the thickness of the flange is greater at the major axis of the light exiting part than that at the minor axis of the light exiting part.

11. The light emitting module of claim 10 , wherein:

the substrate has a predetermined length; and

the lens is arranged so that the major axis of the light exiting part is perpendicular to the longitudinal direction of the substrate.

12. The light emitting module of claim 10 , wherein:

the substrate has a predetermined length; and

a width of the light entering part in the minor axis direction is less than a width of the substrate.

13. The light emitting module of claim 10 , wherein the lens further comprises a plurality of legs arranged in the major axis direction of the light exiting part.

14. The light emitting module of claim 10 , wherein a shortest distance from one end of the light exiting part of the lens at the major axis thereof to one end of the flange at the major axis of the flange is different from a shortest distance from one end of the light exiting part of the lens at the minor axis thereof to one end of the flange at the minor axis of the flange.

15. The light emitting module of claim 10 , wherein the light exiting part has a substantially elliptical planar shape and the flange has a substantially circular planar shape.

16. The light emitting module of claim 15 , wherein the thickness of the flange gradually decreases from the major axis of the light exiting part to the minor axis of the light exiting part along the circumference.

17. The light emitting module of claim 10 , wherein:

the light entering part comprises a light incident vertical surface extending from the lower surface of the lens and a light incident inclined surface extending upward from the light incident vertical surface; and

a height of the light incident vertical surface from the lower surface of the lens is less than the thickness of the flange at the minor axis of the light exiting part.

18. The light emitting module of claim 10 , wherein the lower surface of the lens is substantially parallel to an upper surface of the substrate.