Patent ID: 8430517
Filing Date: 2013-04-30
Classification: G02B

Abstract:
1. A lighting system for a data display device, said lighting system including a light guide into which the light produced by a light source is injected, said lighting system being wherein the light guide includes a plane light injection and collimation zone in the form of a parabola, said parabola including two branches connected to each other via an apex, the light source being arranged opposite the apex, the branches of the parabola which delimit the contour of the plane injection and collimation zone being extended by a plane extraction zone for the light propagating inside the guide, said extraction zone having a rectangular section and being provided with light extractors and in that, if θ i is the angle of acceptance of the parabola and 2a′ the parabola input diameter, then the focal length f of the parabola is: f=a′ (1+sin θ the length L of the parabola is: L=a′ (1+sin θ the parabola output diameter is: a=a′/sin θ