G PHYSICS
G02 OPTICS
G02B OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
G02B6/0001 specially adapted for lighting devices or systems
G02B6/0011 the light guides being planar or of plate-like form
G02B6/0013 Means for improving the coupling-in of light from the light source into the light guide
G02B6/0015 provided on the surface of the light guide or in the bulk of it