Patent ID: 7373273

Claim:
Method for determining a distribution (W(x)) along a main direction (x) of diffusing points on a useful surface, elsewhere reflecting, of a light extractor intended to be coupled to an emission surface, transparent for rays propagating with a smaller angle than a predetermined critical angle (θ max ) and internally reflecting for rays propagating with a greater angle than the critical angle (θ max ), in a diffuser for a light guide lamp having a first illumination system suitable to project the light of a light source in the diffuser with smaller angles than the critical angle (θ max ), the method comprising the steps of: (a) setting a first point (A, x 1 ) of the distribution (W(x)) as the point of final incidence on the extractor closest to the illumination system of a light ray propagating according to a preselected type of trajectory, (b) setting a second point (B, x 2 ) of the distribution (W(x)) as the point of final incidence on the extractor farthest from the illumination system of a light ray propagating according to the preselected type of trajectory, (c) recursively determining, for each point (x i ) of the distribution of points, a new point (X, x) of the distribution as the point of the extractor equally illuminated by a first point source arranged at the preselected point (x i ) of the distribution, and by a second point source arranged at a next adjacent point (x i+1 ) of the distribution, intensities (I(x)) of the point sources being a function of an intensity (K) of the light source and of a characteristic distance of the preselected type of trajectory, wherein a determined distribution of diffusing points is established as including the first point, the second point, and the recursively determined points, and constructing a light extractor based upon the determined distribution of diffusing points.