Electroluminescent panels are nearly as thin as paper, can be twisted and give off light without producing any kind of heat.
The luminance is around 10 and 100 cd/m2.
For comparison only: a CCFL has a 200- up to 2000-fold stronger luminance.
Electroluminescent panels, or in short: EL-panels, are favoured for backlight applications in twilight and darkness.