A compact backlight system for illuminating a display device (12) has a light-emitting panel (1) with a front wall (2) and an opposed rear wall (3) and with edge surfaces (4, 5). At least one of the edge surfaces (4) is light-transmitting. The backlight system has a light source (6) comprising a limited number of LEDs. Light from the light source (6) is coupled into the light-emitting panel (1) via the edge surface that is light-transmitting. According to the invention, the light-emitting panel (1) is wedge-shaped, and the surface area S.sub.i of the light-transmitting edge surface (4) and the surface area S.sub.r of the opposite edge surface (5) fulfill the relation: 1<(S.sub.r/S.sub.i)<10, preferably 1.5<(S.sub.r/S.sub.i)<5. Light travelling for the first time from the light-transmitting edge surface through the light-emitting panel (1) towards the opposite edge surface (5) cannot be coupled out of the light emitting panel (1).

A compact backlight system has a light-emitting panel (1) with a front wall (2), a rear wall (3) situated opposite thereto, a first edge surface (4) and, opposite thereto, a second edge surface (5) . A first light source (6) is associated with the first edge surface (4) which is light-transmitting. The light-emitting panel (1) widens over a widening section (100) from the first edge surface (4) in a direction towards the second edge surface (5), and the rear wall (3) is provided over the widening section (100) with a multiplicity of steps (13, 13', . . . ) each having a surface (17) facing the front wall (2) which is substantially parallel to the front wall (2).

A plurality of first light reflection parts 20a in the form of a first V-shaped groove, for reflecting light entering from a first light source 12a and a plurality of light reflection parts 20b in the form of a second V-shaped groove, for reflecting light entering from a second light source 12b are formed, an intersection angle .theta..sub.P of the planes of the first V-shaped groove and an intersection angle .theta..sub.P of the planes of the second V-shaped grooves are substantially equal to each other, the planes of said plurality of first light reflection parts and the planes of said plurality of second light reflection parts are tilted at respective angles at which the light exits in the direction substantially perpendicular to the longitudinal direction of the linear light conductor 14, said plurality of first light reflection parts are formed in at least a region near the end of the linear light conductor, opposite to the end thereof near which the first light source is disposed, and said plurality of second reflection parts are formed in at least a region near the end of the linear light conductor opposite to the end thereof near which the second light source is disposed.

In a front light, an intermediate light guide protrudes from a light guide plate toward a light emitting element in the direction along a light incident face of the light guide plate. A side face of the intermediate light guide opposing the light incident face serves as an emergent face from which light from the light emitting element is emitted to the light guide plate, and an outer side face remote from the emergent face serves as a reflecting face for reflecting light propagating inside the intermediate light guide. The outer side face of the intermediate light guide is provided with a prism face having a plurality of grooves of wedge-shaped cross section, and a reflective film formed thereon. The prism face is provided distant from an end face of the intermediate light guide close to the light emitting element.

A white light emitting device by using off-white light emitting diodes (LED's). Rather than using just pure white LEDs, the white light emitting device arranges those LEDs which exhibit off-white colors in a manner such that the combination of light emanating from these off-white LEDs produces a radiation which appears substantially pure white to the human eye.