To ensure even in poor lighting situations a good readability of displays, they are depending on the application often supplemented with backlights.
For illuminating transmissive- and transflective displays, LED backlights are used. In dark places, they improve brightness and contrast.
An alternative to LED backlights represents an EL-Foil (electroluminescent foil). Due to their extremely thin structure, they are often used for critical installation situations.
Displays whose construction does not allow a backlight, such as E-Paper, can be illuminated alternatively by a front light.
The following pages do contain detailed information about the addressed lighting types for you.