Patent ID: 7125154

Claim:
Lighting device that comprises: a lightguide comprising a plate ( 1 , 12 ), comprising at least two opposed side edges ( 4 , 6 ), one face ( 3 ) of which has first irregular diffusing patterns ( 8 ) formed in the plate, two light sources ( 13 , 14 ) arranged along two opposed side edges of the plate, at least one third light source arranged along a third side edge of the plate, second irregular diffusing patterns formed in the plate crosscrossing with the first diffusing patterns, each diffusing pattern comprising a groove ( 10 ) bordered by two strips of irregular projections and depressions, each diffusing pattern having irregularities in surface area and depth, the grooves of the first diffusing patterns being spaced apart at varying distances, and the grooves of the second diffusing patterns being spaced apart at varying distances.