Lens and light emitting module for surface illumination

1. A light-emitting module, comprising:

a circuit board;

a light-emitting device disposed on the circuit board; and

a lens disposed on the circuit board, the lens configured to distribute light emitted from the light-emitting device,

wherein the lens comprises:

a first surface comprising a concave portion having an incidence surface configured to receive light emitted from the light-emitting device,

a second surface through which the light incident on the incidence surface of the concave portion exits, and

a flange connecting the first surface and the second surface,

wherein the light-emitting device is disposed within the concave portion of the lens,

wherein the first surface of the lens comprises a flat surface surrounding the concave portion, and an inclination surface surrounding the flat surface and extending to the flange,

wherein the lens further comprises leg portions disposed on the inclination surface between the flat surface and the flange, the leg portions of the lens being connected to the circuit board, and

wherein the inclination surface has an inclination angle of less than 10 degrees with respect to the flat surface of the first surface of the lens.

2. The light-emitting module of claim 1 , further comprising:

a reflective sheet disposed on the circuit board.

3. The light-emitting module of claim 1 , wherein light is configured to exit from the flange at an exit angle greater than 70 degrees.

4. The light-emitting module of claim 1 , wherein the light-emitting device comprises a chip-level light-emitting device.

5. The light-emitting module of claim 4 , wherein the chip-level light emitting device is directly mounted on the circuit board.

6. The light-emitting module of claim 4 , wherein the chip-level light-emitting device comprises:

a light-emitting diode (LED) chip; and

a wavelength conversion layer disposed on the LED chip,

wherein the wavelength conversion layer is disposed on at least two surfaces of the LED chip.

7. The light-emitting module of claim 1 , wherein a width of an entrance of the concave portion of the first surface of the lens is greater than a width of the light-emitting device.

8. The light-emitting module of claim 7 , wherein the width of the entrance of the concave portion of the first surface of the lens is no more than two times greater than the width of the light-emitting device.

9. The light-emitting module of claim 7 , wherein the width of the entrance of the concave portion of the first surface of the lens is no more than 3 mm.

10. The light-emitting module of claim 1 , wherein the incidence surface of the lens is an inner surface of the concave portion.

11. The light-emitting module of claim 10 , wherein the incidence surface of the lens comprises an upper end surface and a side surface continuing to an entrance of the concave portion from the upper end surface.

12. The light-emitting module of claim 11 , wherein the concave portion of the first surface of the lens comprises a shape narrowing as the concave portion of the first surface of the lens extends upward from an entrance of the concave portion of the first surface of the lens to the upper end surface.

13. The light-emitting module of claim 12 , wherein the side surface comprises an inclination surface having a constant slope from the entrance to the upper end surface, or the side surface comprises a curved inclination surface decreasing at a slope from the entrance to the upper end surface.

14. The light-emitting module of claim 11 , wherein the upper end surface comprises a flat surface, a concave surface, or a convex surface.

15. The light-emitting module of claim 11 , wherein the upper end surface comprises a light-scattering pattern.

16. The light-emitting module of claim 1 , wherein the second surface of the lens comprises a concave surface disposed near a central axis of the lens, and a convex surface extending from the concave surface.

17. The light-emitting module of claim 1 , wherein the second surface of the lens comprises a flat surface disposed near a central axis of the lens, and a convex surface extending from the flat surface.