Backlighting apparatus

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,
• characterized by the fact that said device additionally comprises at least one third light source arranged along a third side edge of the plate, and second irregular diffusing patterns formed in the plate, which crisscross with the first diffusing patterns.

Lightguide comprising a plate (1,12) having two parallel faces (2,3) and at least two opposed side edges (4,6), with a first face (3) having a plurality of first irregular elongate diffusing patterns (8,10), characterized by the fact that said guide comprises second irregular elongate diffusing patterns (9,10) crisscrossing the first diffusing patterns.

Process for manufacturing a lightguide in the form of a plate whose one face (3) comprises a plurality of diffusing patterns (8,10) obtained using a laser beam, wherein said face is exposed to a radiation whose intensity is sufficient (generally lying in a range from 104 to 107 cm2) to form irregularities in surface area and depth, and so that each of said patterns comprises a central depression and peripheral protrusions arranged on both sides of said central depression, characterized by the fact that the material used is chosen from among glass, polycarbonate and methyl polymethacrylate, and wherein a first network of first essentially parallel diffusing patterns (8,10) is formed, followed by a second network of second essentially parallel diffusing patterns (9,10), which extend obliquely, preferably essentially orthogonally, to the first diffusing patterns.