Patent ID: 6962429

Claim:
A backlight device comprising: a light guide plate having a light incident face and a light emission face; a rotary member adapted to be rotated along a rotary shaft thereof and disposed opposite to the light incident face of the light guide plate; a rotary drive mechanism for rotating the rotary member; a plurality of mercury-free fluorescent lamps, each comprising an arc tube mounted on the rotary member so as to extend substantially parallel to the rotary shaft, a mercury-free discharge medium consisting essentially of a rare gas sealed within the arc tube, and first and second electrodes for exciting the discharge medium, the mercury-free fluorescent lamps being capable of emitting light of respectively different colors, and the emitted light entering the light guide plate through the light incident face and emerging from the light emission face; and a power feed control mechanism for applying a voltage to the first and second electrodes of each of the mercury-free fluorescent lamps, wherein the first electrode is arranged within the arc tube, and wherein the second electrode comprises a plurality of segmented electrodes arranged on an outer surface of the rotary member so as to be spaced apart from each other in an extending direction of the rotary shaft, and contacting with an outer peripheral surface of the arc tube.