Patent ID: 8042975
Filing Date: 2011-10-25
Classification: G02B,H04M

Abstract:
1. A plano-Fresnel LED (Light emitting diode) lens, applied to a LED assembly having a LED chip, a gel layer and a lens along a central axis from a source side to a forward side, comprising: an optical surface on the forward side and an optical surface on the source side; wherein the optical surface on forward side is a plano-Fresnel optical surface with vertical draft so as to make light from the LED chip pass through the gel layer, the lens and form an elliptic distribution pattern on the forward side, and the lens satisfies conditions of: wherein f s is effective focal length, r n is radius of a last zone of a Fresnel optical surface, d 2 is thickness of the lens on a central axis, and N d2 is refractive index of the lens.