A light-guiding device having a coupling-in surface (46) for coupling-in light radiation substantially in a first main direction (41) perpendicular to said coupling-in surface (26;46), and having a coupling-out surface (47,48,49) for coupling-out light radiation substantially in a second main direction (42) perpendicular to said coupling-out surface. The coupling-out surface has other dimensions than the coupling-in surface (46). The device comprises a number of plate-like light-guiding members (43,44,45), each having a substantially rectangular lateral coupling-in surface and a substantially rectangular lateral coupling-out surface (47,48,49). A number of the plate-like light-guiding members are stacked together to create the coupling-in surface (46) formed by said lateral coupling-in surfaces abutting each other at their long sides. The coupling-out surface (47,48,49) is created by said lateral coupling-out surfaces abutting each other at their short sides.