Patent ID: 7625102

Claim:
A lighting device comprising: at least one light source having an optical axis; and a projection lens having an optical axis and a source-side focal position, the projection lens located adjacent said light source so that the source-side focal position is located substantially at said light source and the optical axis of the projection lens substantially coincides with the optical axis of said light source, said projection lens being a distribution control lens of convex form having an exit surface that is aspherically shaped so that a direction of emission light is continuously refracted into a certain direction with respect to an angle of incidence θ1 of light originating from the focal position, the aspherically shaped exit surface of the distribution control lens including a concave surface portion located between a first convex surface and a second convex surface, the optical axis of the projection lens intersecting the concave surface portion; wherein the aspherically shaped exit surface of the distribution control lens is configured such that an angle of emission θ2 is related to the angle of incidence θ1 in accordance with the formula θ2=0.2θ1.