Patent ID: 8684585

Claim:
An illumination device comprising: a lens comprising: a surrounding sidewall comprising two planar portions and two arc-surface portions to surround a reference axis, the two planar portions being opposite to each other, the two arc-surface portions being opposite to each other; a light-incident surface located at one side of the surrounding sidewall to receive a light emitted from a point light source; a light-incident structure located on the light-incident surface and comprising a plurality of first bar-shaped protrusions, each of the first bar-shaped protrusions having at least one first light-diffusing surface not parallel to the light-incident surface; and a light-emitting surface located at the other side of the surrounding sidewall and being opposite to the light-incident surface, the light-emitting surface being substantially circular, a cross-section area of the lens gradually increasing from the light-incident surface to the light-emitting surface; a light guide cylinder configured at a side of the lens away from the point light source and substantially aligned to the reference axis; and a reflective layer configured at a side of the light guide cylinder and exposing an opposite side of the light guide cylinder, the reflective layer and one of the two planar portions being located at a same side of the reference axis, wherein the planar portions correspond to the reflective layer of the illumination device.