Lens and illumination device comprising the lens

1. A lens for an illumination device, the lens comprising:

a bottom wall,

a top wall, and

a circumferential wall, the circumferential wall connecting the bottom wall and the top wall,

wherein a plurality of regions of the bottom wall respectively arch towards the top wall to define at least one first accommodation cavity having an inner wall configured as a first incident surface, and at least one second accommodation cavity having an inner wall configured as a second incident surface, the first incident surface and the second incident surface being configured as different curved surfaces for receiving first incident light and second incident light, respectively,

wherein the second incident surface is a non-rotationally symmetrical curved surface with respect to a line between a vertex of the second incident surface and a midpoint between both end points of a projection of the second incident surface on the bottom wall, the vertex of the second incident surface in a cross section, being located on a side, away from the first incident surface, of a midline of a projection of the second incident surface on a horizontal plane, and

wherein the second incident surface has, in a cross section, a curve profile defined by the formula: y=−1E-08x^6+2E-06x^5−0.0001x^4+0.0032x^3−0.0633x^2+1.4584x+1E-06.

2. The lens according to claim 1 ,

wherein the first incident surface is a symmetrical curved surface, and the second incident surface is an asymmetrical curved surface.

3. The lens according to claim 2 ,

wherein the first incident surface is a rotationally symmetrical curved surface.

4. The lens according to claim 3 ,

wherein the first incident surface is a spherical surface.

5. The lens according to claim 1 ,

wherein the top wall is configured as an emergent surface consisting of a micro-lens array.

6. The lens according to claim 1 ,

wherein the accommodation cavities are arranged to be separated from each other.

7. The lens according to claim 1 ,

wherein the circumferential wall is configured as a total internal reflection surface having a curved surface profile.

8. The lens according to claim 1 ,

wherein the number of the second accommodation cavity is more than one, and the second accommodation cavities are uniformly arranged around the first accommodation cavity.

9. An illumination device comprising:

at least one first light source,

at least one second light source, and

a lens,

the lens comprising:

a bottom wall,

a top wall, and

a circumferential wall, the circumferential wall connecting the bottom wall and the top wall,

wherein a plurality of regions of the bottom wall respectively arch towards the top wall to define at least one first accommodation cavity having an inner wall configured as a first incident surface, and at least one second accommodation cavity having an inner wall configured as a second incident surface, the first incident surface and the second incident surface being configured as different curved surfaces for receiving first incident light and second incident light, respectively,

wherein the second incident surface is a non-rotationally symmetrical curved surface with respect to a line between a vertex of the second incident surface and a midpoint between both end points of a projection of the second incident surface on the bottom wall, the vertex of the second incident surface, in a cross section, being located on a side, away from the first incident surface, of a midline of a projection of the second incident surface on a horizontal plane, and

wherein the second incident surface has, in a cross section, a curve profile defined by the formula: y=−1E-08x^6+2E-06x^5−0.0001x^4+0.0032x^3−0.0633x^2+1.4584x+1E-06.

10. The illumination device according to claim 9 ,

wherein light emitted from the at least one first light source and light emitted from the at least one second light source have different color temperatures.

11. The illumination device according to claim 9 , further comprising:

a circuit board carrying the first and second light sources, and

a heat sink,

wherein the first light source is accommodated in the first accommodation cavity of the lens, and the second light source is accommodated in the second accommodation cavity of the lens.

12. The illumination device according to claim 11 ,

wherein the heat sink comprises an accommodation portion accommodating the lens and the circuit board.

13. The illumination device according to claim 11 ,

wherein the heat sink is configured as a circular structure having heat dissipating ribs on a circumferential wall, and the accommodation portion is arranged in the center of the heat sink.

14. The illumination device according to claim 11 ,

wherein the circuit board comprises control circuits controlling a working state of the first and second light sources, respectively.