Add backlight to LCD
If you have an LCD display that does not have a backlight, you can easily modify it to add your own. On the bottom side of the LCD glass you can find polarising and reflecting films. This mod process involves pealing off the reflecting film so that LED light can travel through the glass to enlighten the display.
It is very important not to peal off the polarising film and if that should happen, it should be glued back to the LCD glass. LED light source is made out of LEDs and some sort of light-medium. For that purpose, some kind of diffused plastic can be used.
LCD display structure: LCD
© AP Digital light
Another document that describes this process in detail can be found here.