Patent ID: 7342728
Filing Date: 2008-03-11
Classification: B29D,G02B,G03B

Abstract:
1. Fresnel lens comprising: a first face lying in a plane; and opposite this face, a second face parallel to the first face; and including circular concentric refractive structures, each refractive structure being defined by: each said structure being intended to be illuminated by a beam making an entrance angle different from zero degrees with the normal to the said plane, the directions of said beam and of said normal being substantially different, wherein the second face has at least two zones of refractive structures distributed between the centre of the concentric refractive structures and the periphery of the Fresnel lens: a first zone close to the centre, in which: a second zone in which: the first angle of each first surface is such that the refractive structures refract the said beam along a direction making a non-zero angle smaller than a maximum value relative to the optical axis and