Light guide with decoupling portion and shield collecting the decoupled rays

摘要

A light guide comprising an external surface forming a guiding diopter, the guide being suitable for guiding light rays by reflection on the guiding diopter. The guide comprises at least one decoupling portion, with a refraction decoupling diopter arranged so as to refract light rays to decouple them from the guide, and thus transmit them out of the guide through the refraction decoupling diopter.

主权项

1. A light guide comprising an external surface forming a guiding diopter, said light guide being suitable for guiding light rays by reflection on said guiding diopter;
wherein said light guide comprises a section comprising at least one decoupling portion, with a refraction decoupling diopter arranged so as to refract light rays to cause at least a portion of said light rays to leave said light guide and transmit them out of said light guide through said refraction decoupling diopter; said at least one decoupling portion being arranged in substantial proximity to an input end of said light guide and defining a variable cross-section that generally decreases as it extends from an input face of said light guide to an end of said at least one decoupling portion, wherein said at least a portion of said light rays originating from said input end of said light guide are not reflected by said guiding diopter; said at least one decoupling portion comprising an external surface arranged such that an angle of incidence of said at least a portion of said light rays with said external surface is less than a limiting angle between a refraction and a total reflection so that said at least a portion of said light rays passing through said at least one decoupling portion will be refracted by said at least one decoupling portion out of and away from said light guide; wherein said light guide further comprises at least one shield spaced apart from and generally opposed to said at least one decoupling portion and arranged so as to collect said portion of said light rays leaving said at least one decoupling portion and reflect them back into said light guide.