Patent ID: 7922367

Claim:
An optical element, comprising: a bottom surface; at least one side refractive surface, for refracting one part of a light beam incident from the bottom surface; and an upper refractive surface, for refracting the other part of the light beam incident from the bottom surface, wherein the upper refractive surface comprises a smooth aspherical concave surface and the cross section of the upper refractive surface comprises a concave curve and two convex curves at both sides of the concave curve; wherein a maximum included angle formed between the light beam incident from the bottom surface and to be irradiated onto the side refractive surface and the bottom surface is a first angle (α), and an included angle formed between a light beam coming out from at least one side refractive surface and the bottom surface is smaller than or equal to the first angle; and a maximum included angle formed between the light beam incident from the bottom surface and to be irradiated onto the upper refractive surface and a central axis of the optical element is a second angle (β), and an included angle formed between the light beam coming out from the upper refractive surface and a central axis of the optical element is greater than or equal to the second angle, and wherein said optical element enables the energy of the emitted light to uniformly-distribute at an angle of 0˜90 with respect to the central axis.